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Wikipedia

Video camera tube

Video camera tubes were devices based on the cathode ray tube that were used in television cameras to capture television images prior to the introduction of charge-coupled device (CCD) image sensors in the 1980s. Several different types of tubes were in use from the early 1930s, and as late as the 1990s.

vidicon tube (23 inch (17 mm) in diameter)
A display of a variety of early experimental video camera tubes from 1954, with Vladimir K. Zworykin who invented the iconoscope

In these tubes, the cathode ray was scanned across an image of the scene to be broadcast. The resultant current was dependent on the brightness of the image on the target. The size of the striking ray was tiny compared to the size of the target, allowing 483 horizontal scan lines per image in the NTSC format, 576 lines in PAL, and as many as 1035 lines in HiVision.

Contents

Main article: Cathode ray tube

Any vacuum tube which operates using a focused beam of electrons, originally called cathode rays, is known as a cathode ray tube (CRT). These are usually seen as display devices as used in older (i.e., non-flat panel) television receivers and computer displays. The camera pickup tubes described in this article are also CRTs, but they display no image.

In June 1908, the scientific journal Nature published a letter in which Alan Archibald Campbell-Swinton, fellow of the Royal Society (UK), discussed how a fully electronic television system could be realized by using cathode ray tubes (or "Braun" tubes, after their inventor, Karl Braun) as both imaging and display devices. He noted that the "real difficulties lie in devising an efficient transmitter", and that it was possible that "no photoelectric phenomenon at present known will provide what is required". A cathode ray tube was successfully demonstrated as a displaying device by the German Professor Max Dieckmann in 1906, his experimental results were published by the journal Scientific American in 1909. Campbell-Swinton later expanded on his vision in a presidential address given to the Röntgen Society in November 1911. The photoelectric screen in the proposed transmitting device was a mosaic of isolated rubidium cubes. His concept for a fully electronic television system was later popularized by Hugo Gernsback as the "Campbell-Swinton Electronic Scanning System" in the August 1915 issue of the popular magazine Electrical Experimenter.

In a letter to Nature published in October 1926, Campbell-Swinton also announced the results of some "not very successful experiments" he had conducted with G. M. Minchin and J. C. M. Stanton. They had attempted to generate an electrical signal by projecting an image onto a selenium-coated metal plate that was simultaneously scanned by a cathode ray beam. These experiments were conducted before March 1914, when Minchin died, but they were later repeated by two different teams in 1937, by H. Miller and J. W. Strange from EMI, and by H. Iams and A. Rose from RCA. Both teams succeeded in transmitting "very faint" images with the original Campbell-Swinton's selenium-coated plate, but much better images were obtained when the metal plate was covered with zinc sulphide or selenide, or with aluminum or zirconium oxide treated with caesium. These experiments would form the base of the future vidicon. A description of a CRT imaging device also appeared in a patent application filed by Edvard-Gustav Schoultz in France in August 1921, and published in 1922, although a working device was not demonstrated until some years later.

Farnsworth image dissector tube from 1931
Main article: Image dissector

An image dissector is a camera tube that creates an "electron image" of a scene from photocathode emissions (electrons) which pass through a scanning aperture to an anode, which serves as an electron detector. Among the first to design such a device were German inventors Max Dieckmann and Rudolf Hell, who had titled their 1925 patent application Lichtelektrische Bildzerlegerröhre für Fernseher (Photoelectric Image Dissector Tube for Television). The term may apply specifically to a dissector tube employing magnetic fields to keep the electron image in focus, an element lacking in Dieckmann and Hell's design, and in the early dissector tubes built by American inventor Philo Farnsworth.

Dieckmann and Hell submitted their application to the German patent office in April 1925, and a patent was issued in October 1927. Their experiments on the image dissector were announced in the volume 8 (September 1927) of the popular magazine Discovery and in the May 1928 issue of the magazine Popular Radio. However, they never transmitted a clear and well focused image with such a tube.[citation needed]

In January 1927, American inventor and television pioneer Philo T. Farnsworth applied for a patent for his Television System that included a device for "the conversion and dissecting of light". Its first moving image was successfully transmitted on September 7 of 1927, and a patent was issued in 1930. Farnsworth quickly made improvements to the device, among them introducing an electron multiplier made of nickel and using a "longitudinal magnetic field" in order to sharply focus the electron image. The improved device was demonstrated to the press in early September 1928. The introduction of a multipactor in October 1933 and a multi-dynode "electron multiplier" in 1937 made Farnsworth's image dissector the first practical version of a fully electronic imaging device for television. Unfortunately, it had very poor light sensitivity, and was therefore primarily useful only where illumination was exceptionally high (typically over 685 cd/m2). However, it was ideal for industrial applications, such as monitoring the bright interior of an industrial furnace. Due to their poor light sensitivity, image dissectors were rarely used in television broadcasting, except to scan film and other transparencies.[citation needed]

In April 1933, Farnsworth submitted a patent application also entitled Image Dissector, but which actually detailed a CRT-type camera tube. This is among the first patents to propose the use of a "low-velocity" scanning beam and RCA had to buy it in order to sell image orthicon tubes to the general public. However, Farnsworth never transmitted a clear and well focused image with such a tube.

Operation

The optical system of the image dissector focuses an image onto a photocathode mounted inside a high vacuum. As light strikes the photocathode, electrons are emitted in proportion to the intensity of the light (see photoelectric effect). The entire electron image is deflected and a scanning aperture permits only those electrons emanating from a very small area of the photocathode to be captured by the detector at any given time. The output from the detector is an electric current whose magnitude is a measure of the brightness of the corresponding area of the image. The electron image is periodically deflected horizontally and vertically ("raster scanning") such that the entire image is read by the detector many times per second, producing an electrical signal that can be conveyed to a display device, such as a CRT monitor, to reproduce the image.

The image dissector has no "charge storage" characteristic; the vast majority of electrons emitted by the photocathode are excluded by the scanning aperture, and thus wasted rather than being stored on a photo-sensitive target, as in the iconoscope or image orthicon (see below), which largely accounts for its low light sensitivity.

Zworykin holding an iconoscope tube
Diagram of the iconoscope, from Zworykin's 1931 patent
Main article: Iconoscope

An iconoscope is a camera tube that projects an image on a special charge storage plate containing a mosaic of electrically isolated photosensitive granules separated from a common plate by a thin layer of isolating material, somewhat analogous to the human eye's retina and its arrangement of photoreceptors. Each photosensitive granule constitutes a tiny capacitor that accumulates and stores electrical charge in response to the light striking it. An electron beam periodically sweeps across the plate, effectively scanning the stored image and discharging each capacitor in turn such that the electrical output from each capacitor is proportional to the average intensity of the light striking it between each discharge event.

After Hungarian engineer Kálmán Tihanyi studied Maxwell's equations, he discovered a new hitherto unknown physical phenomenon, which led to a break-through in the development of electronic imaging devices. He named the new phenomenon as charge-storage principle. (further information: Charge-storage principle) The problem of low sensitivity to light resulting in low electrical output from transmitting or camera tubes would be solved with the introduction of charge-storage technology by the Hungarian engineer Kálmán Tihanyi in the beginning of 1925. His solution was a camera tube that accumulated and stored electrical charges (photoelectrons) within the tube throughout each scanning cycle. The device was first described in a patent application he filed in Hungary in March 1926 for a television system he dubbed Radioskop. After further refinements included in a 1928 patent application, Tihanyi's patent was declared void in Great Britain in 1930, and so he applied for patents in the United States. Tihanyi's charge storage idea remains a basic principle in the design of imaging devices for television to the present day.

In 1923, while employed by the Westinghouse Electric Corporation in Pittsburgh, Pennsylvania, Russian-born American engineer Vladimir Zworykin presented a project for a totally electronic television system to the company's general manager. In July 1925, Zworykin submitted a patent application titled Television System that included a charge storage plate constructed of a thin layer of isolating material (aluminum oxide) sandwiched between a screen (300 mesh) and a colloidal deposit of photoelectric material (potassium hydride) consisting of isolated globules. The following description can be read between lines 1 and 9 in page 2: "The photoelectric material, such as potassium hydride, is evaporated on the aluminum oxide, or other insulating medium, and treated so as to form a colloidal deposit of potassium hydride consisting of minute globules. Each globule is very active photoelectrically and constitutes, to all intents and purposes, a minute individual photoelectric cell". Its first image was transmitted in late summer of 1925, and a patent was issued in 1928. However the quality of the transmitted image failed to impress H.P. Davis, the general manager of Westinghouse, and Zworykin was asked "to work on something useful". A patent for a television system was also filed by Zworykin in 1923, but this filing is not a definitive reference because extensive revisions were done before a patent was issued fifteen years later and the file itself was divided into two patents in 1931.


The first practical iconoscope was constructed in 1931 by Sanford Essig, when he accidentally left a silvered mica sheet in the oven too long. Upon examination with a microscope, he noticed that the silver layer had broken up into a myriad of tiny isolated silver globules. He also noticed that, "the tiny dimension of the silver droplets would enhance the image resolution of the iconoscope by a quantum leap". As head of television development at Radio Corporation of America (RCA), Zworykin submitted a patent application in November 1931, and it was issued in 1935. Nevertheless, Zworykin's team was not the only engineering group working on devices that used a charge storage plate. In 1932, the EMI engineers Tedham and McGee under the supervision of Isaac Shoenberg applied for a patent for a new device they dubbed the "Emitron". A 405-line broadcasting service employing the Emitron began at studios in Alexandra Palace in 1936, and patents were issued in the United Kingdom in 1934 and in the US in 1937.

The iconoscope was presented to the general public at a press conference in June 1933, and two detailed technical papers were published in September and October of the same year. Unlike the Farnsworth image dissector, the Zworykin iconoscope was much more sensitive, useful with an illumination on the target between 4ft-c (43lx) and 20ft-c (215lx). It was also easier to manufacture and produced a very clear image.[citation needed] The iconoscope was the primary camera tube used by RCA broadcasting from 1936 until 1946, when it was replaced by the image orthicon tube.

The original iconoscope was noisy, had a high ratio of interference to signal, and ultimately gave disappointing results, especially when compared to the high definition mechanical scanning systems then becoming available. The EMI team under the supervision of Isaac Shoenberg analyzed how the Emitron (or iconoscope) produces an electronic signal and concluded that its real efficiency was only about 5% of the theoretical maximum. This is because secondary electrons released from the mosaic of the charge storage plate when the scanning beam sweeps across it may be attracted back to the positively charged mosaic, thus neutralizing many of the stored charges. Lubszynski, Rodda, and McGee realized that the best solution was to separate the photo-emission function from the charge storage one, and so communicated their results to Zworykin.

The new video camera tube developed by Lubszynski, Rodda and McGee in 1934 was dubbed "the super-Emitron". This tube is a combination of the image dissector and the Emitron. It has an efficient photocathode that transforms the scene light into an electron image; the latter is then accelerated towards a target specially prepared for the emission of secondary electrons. Each individual electron from the electron image produces several secondary electrons after reaching the target, so that an amplification effect is produced. The target is constructed of a mosaic of electrically isolated metallic granules separated from a common plate by a thin layer of isolating material, so that the positive charge resulting from the secondary emission is stored in the granules. Finally, an electron beam periodically sweeps across the target, effectively scanning the stored image, discharging each granule, and producing an electronic signal like in the iconoscope.

The super-Emitron was between ten and fifteen times more sensitive than the original Emitron and iconoscope tubes and, in some cases, this ratio was considerably greater. It was used for an outside broadcast by the BBC, for the first time, on Armistice Day 1937, when the general public could watch in a television set how the King laid a wreath at the Cenotaph. This was the first time that anyone could broadcast a live street scene from cameras installed on the roof of neighboring buildings.

On the other hand, in 1934, Zworykin shared some patent rights with the German licensee company Telefunken. The image iconoscope (Superikonoskop in Germany) was produced as a result of the collaboration. This tube is essentially identical to the super-Emitron, but the target is constructed of a thin layer of isolating material placed on top of a conductive base, the mosaic of metallic granules is missing. The production and commercialization of the super-Emitron and image iconoscope in Europe were not affected by the patent war between Zworykin and Farnsworth, because Dieckmann and Hell had priority in Germany for the invention of the image dissector, having submitted a patent application for their Lichtelektrische Bildzerlegerröhre für Fernseher (Photoelectric Image Dissector Tube for Television) in Germany in 1925, two years before Farnsworth did the same in the United States.

The image iconoscope (Superikonoskop) became the industrial standard for public broadcasting in Europe from 1936 until 1960, when it was replaced by the vidicon and plumbicon tubes. Indeed, it was the representative of the European tradition in electronic tubes competing against the American tradition represented by the image orthicon. The German company Heimann produced the Superikonoskop for the 1936 Berlin Olympic Games, later Heimann also produced and commercialized it from 1940 to 1955, finally the Dutch company Philips produced and commercialized the image iconoscope and multicon from 1952 to 1958.

Operation

The super-Emitron is a combination of the image dissector and the Emitron. The scene image is projected onto an efficient continuous-film semitransparent photocathode that transforms the scene light into a light-emitted electron image, the latter is then accelerated (and focused) via electromagnetic fields towards a target specially prepared for the emission of secondary electrons. Each individual electron from the electron image produces several secondary electrons after reaching the target, so that an amplification effect is produced, and the resulting positive charge is proportional to the integrated intensity of the scene light. The target is constructed of a mosaic of electrically isolated metallic granules separated from a common plate by a thin layer of isolating material, so that the positive charge resulting from the secondary emission is stored in the capacitor formed by the metallic granule and the common plate. Finally, an electron beam periodically sweeps across the target, effectively scanning the stored image and discharging each capacitor in turn such that the electrical output from each capacitor is proportional to the average intensity of the scene light between each discharge event (as in the iconoscope).

The image iconoscope is essentially identical to the super-Emitron, but the target is constructed of a thin layer of isolating material placed on top of a conductive base, the mosaic of metallic granules is missing. Therefore, secondary electrons are emitted from the surface of the isolating material when the electron image reaches the target, and the resulting positive charges are stored directly onto the surface of the isolated material.

The original iconoscope was very noisy due to the secondary electrons released from the photoelectric mosaic of the charge storage plate when the scanning beam swept it across. An obvious solution was to scan the mosaic with a low-velocity electron beam which produced less energy in the neighborhood of the plate such that no secondary electrons were emitted at all. That is, an image is projected onto the photoelectric mosaic of a charge storage plate, so that positive charges are produced and stored there due to photo-emission and capacitance, respectively. These stored charges are then gently discharged by a low-velocity electron scanning beam, preventing the emission of secondary electrons. Not all the electrons in the scanning beam may be absorbed in the mosaic, because the stored positive charges are proportional to the integrated intensity of the scene light. The remaining electrons are then deflected back into the anode, captured by a special grid, or deflected back into an electron multiplier.

Low-velocity scanning beam tubes have several advantages; there are low levels of spurious signals and high efficiency of conversion of light into signal, so that the signal output is maximum. However, there are serious problems as well, because the electron beam spreads and accelerates in a direction parallel to the target when it scans the image's borders and corners, so that it produces secondary electrons and one gets an image that is well focused in the center but blurry in the borders. Henroteau was among the first inventors to propose in 1929 the use of low-velocity electrons for stabilizing the potential of a charge storage plate, but Lubszynski and the EMI team were the first engineers in transmitting a clear and well focused image with such a tube. Another improvement is the use of a semitransparent charge storage plate. The scene image is then projected onto the back side of the plate, while the low-velocity electron beam scans the photoelectric mosaic at the front side. This configurations allows the use of a straight camera tube, because the scene to be transmitted, the charge storage plate, and the electron gun can be aligned one after the other.

CPS Emitron television camera

The first fully functional low-velocity scanning beam tube, the CPS Emitron, was invented and demonstrated by the EMI team under the supervision of Sir Isaac Shoenberg. In 1934, the EMI engineers Blumlein and McGee filed for patents for television transmitting systems where a charge storage plate was shielded by a pair of special grids, a negative (or slightly positive) grid lay very close to the plate, and a positive one was placed further away. The velocity and energy of the electrons in the scanning beam were reduced to zero by the decelerating electric field generated by this pair of grids, and so a low-velocity scanning beam tube was obtained. The EMI team kept working on these devices, and Lubszynski discovered in 1936 that a clear image could be produced if the trajectory of the low-velocity scanning beam was nearly perpendicular (orthogonal) to the charge storage plate in a neighborhood of it. The resulting device was dubbed the cathode potential stabilized Emitron, or CPS Emitron. The industrial production and commercialization of the CPS Emitron had to wait until the end of the second world war.

On the other side of the Atlantic, the RCA team led by Albert Rose began working in 1937 on a low-velocity scanning beam device they dubbed the orthicon. Iams and Rose solved the problem of guiding the beam and keeping it in focus by installing specially designed deflection plates and deflection coils near the charge storage plate to provide a uniform axial magnetic field. The orthicon was the tube used in RCA's television demonstration at the 1939 New York World's Fair, its performance was similar to the image iconoscope's one, but it was also unstable under sudden flashes of bright light, producing "the appearance of a large drop of water evaporating slowly over part of the scene".

Schematic of image orthicon tube
A 1960s-era RCA Radiotron Image Orthicon TV Camera Tube

The image orthicon (sometimes abbreviated IO), was common in American broadcasting from 1946 until 1968. A combination of the image dissector and the orthicon technologies, it replaced the iconoscope in the United States, which required a great deal of light to work adequately.

The image orthicon tube was developed at RCA by Albert Rose, Paul K. Weimer, and Harold B. Law. It represented a considerable advance in the television field, and after further development work, RCA created original models between 1939 and 1940. The National Defense Research Committee entered into a contract with RCA where the NDRC paid for its further development. Upon RCA's development of the more sensitive image orthicon tube in 1943, RCA entered into a production contract with the U.S. Navy, the first tubes being delivered in January 1944. RCA began production of image orthicons for civilian use in the second quarter of 1946.

While the iconoscope and the intermediate orthicon used capacitance between a multitude of small but discrete light sensitive collectors and an isolated signal plate for reading video information, the image orthicon employed direct charge readings from a continuous electronically charged collector. The resultant signal was immune to most extraneous signal crosstalk from other parts of the target, and could yield extremely detailed images. For instance, image orthicon cameras were still being used by NASA for capturing Apollo/Saturn rockets nearing orbit, although the television networks had phased the cameras out. Only they could provide sufficient detail.

An image orthicon camera can take television pictures by candlelight because of the more ordered light-sensitive area and the presence of an electron multiplier at the base of the tube, which operated as a high-efficiency amplifier. It also has a logarithmic light sensitivity curve similar to the human eye. However, it tends to flare in bright light, causing a dark halo to be seen around the object; this anomaly was referred to as blooming in the broadcast industry when image orthicon tubes were in operation. Image orthicons were used extensively in the early color television cameras, where the increased sensitivity of the tube was essential to overcome the very inefficient optical system of the camera.

The image orthocon tube was at one point colloquially referred to as an Immy. Harry Lubcke, the then-President of the Academy of Television Arts & Sciences, decided to have their award named after this nickname. Since the statuette was female, it was feminized into Emmy.

Operation

An image orthicon consists of three parts: a photocathode with an image store (target), a scanner that reads this image (an electron gun), and a multistage electron multiplier.

In the image store, light falls upon the photocathode which is a photosensitive plate at a very negative potential (approx. -600 V), and is converted into an electron image (a principle borrowed from the image dissector). This electron rain is then accelerated towards the target (a very thin glass plate acting as a semi-isolator) at ground potential (0 V), and passes through a very fine wire mesh (nearly 200 wires per cm), very near (a few hundredths of a cm) and parallel to the target, acting as a screen grid at a slightly positive voltage (approx +2 V). Once the image electrons reach the target, they cause a splash of electrons by the effect of secondary emission. On average, each image electron ejects several splash electrons (thus adding amplification by secondary emission), and these excess electrons are soaked up by the positive mesh effectively removing electrons from the target and causing a positive charge on it in relation to the incident light in the photocathode. The result is an image painted in positive charge, with the brightest portions having the largest positive charge.

A sharply focused beam of electrons (a cathode ray) is generated by the electron gun at ground potential and accelerated by the anode (the first dynode of the electron multiplier) around the gun at a high positive voltage (approx. +1500 V). Once it exits the electron gun, its inertia makes the beam move away from the dynode towards the back side of the target. At this point the electrons lose speed and get deflected by the horizontal and vertical deflection coils, effectively scanning the target. Thanks to the axial magnetic field of the focusing coil, this deflection is not in a straight line, thus when the electrons reach the target they do so perpendicularly avoiding a sideways component. The target is nearly at ground potential with a small positive charge, thus when the electrons reach the target at low speed they are absorbed without ejecting more electrons. This adds negative charge to the positive charge until the region being scanned reaches some threshold negative charge, at which point the scanning electrons are reflected by the negative potential rather than absorbed (in this process the target recovers the electrons needed for the next scan). These reflected electrons return down the cathode ray tube toward the first dynode of the electron multiplier surrounding the electron gun which is at high potential. The number of reflected electrons is a linear measure of the target's original positive charge, which, in turn, is a measure of brightness.

Dark halo

Dark halo around bright rocket flame in television of John Glenn's liftoff of Mercury-Atlas 6 in 1962

The mysterious dark "orthicon halo" around bright objects in an orthicon-captured image is based on the fact that the IO relies on the emission of photoelectrons, but very bright illumination can produce more of them locally than the device can successfully deal with. At a very bright point on a captured image, a great preponderance of electrons is ejected from the photosensitive plate. So many may be ejected that the corresponding point on the collection mesh can no longer soak them up, and thus they fall back to nearby spots on the target instead, much as water splashes in a ring when a rock is thrown into it. Since the resultant splashed electrons do not contain sufficient energy to eject further electrons where they land, they will instead neutralize any positive charge that has been built-up in that region. Since darker images produce less positive charge on the target, the excess electrons deposited by the splash will be read as a dark region by the scanning electron beam.[citation needed]

This effect was actually cultivated by tube manufacturers to a certain extent, as a small, carefully controlled amount of the dark halo has the effect of crispening the visual image due to the contrast effect. (That is, giving the illusion of being more sharply focused than it actually is). The later vidicon tube and its descendants (see below) do not exhibit this effect, and so could not be used for broadcast purposes until special detail correction circuitry could be developed.

A vidicon tube is a video camera tube design in which the target material is a photoconductor. The vidicon was developed in the 1950s at RCA by P. K. Weimer, S. V. Forgue and R. R. Goodrich as a simple alternative to the structurally and electrically complex image orthicon.[citation needed] While the initial photoconductor used was selenium, other targets—including silicon diode arrays—have been used.

Schematic of vidicon tube.

The vidicon is a storage-type camera tube in which a charge-density pattern is formed by the imaged scene radiation on a photoconductive surface which is then scanned by a beam of low-velocity electrons. The fluctuating voltage coupled out to a video amplifier can be used to reproduce the scene being imaged. The electrical charge produced by an image will remain in the face plate until it is scanned or until the charge dissipates. By using a pyroelectric material such as triglycine sulfate (TGS) as the target, a vidicon sensitive over a broad portion of the infrared spectrum is possible. This technology was a precursor to modern microbolometer technology, and mainly used in firefighting thermal cameras.

Prior to the design and construction of the Galileo probe to Jupiter in the late 1970s to early 1980s, NASA used vidicon cameras on nearly all the unmanned deep space probes equipped with the remote sensing ability. Vidicon tubes were also used aboard the first three Landsat earth imaging satellites launched in 1972, as part of each spacecraft's Return Beam Vidicon (RBV) imaging system. The Uvicon, a UV-variant Vidicon was also used by NASA for UV duties.

Vidicon tubes were popular in 1970s and 1980s, after which they were rendered obsolete by solid-state image sensors, with the charge-coupled device (CCD) and then the CMOS sensor.

All vidicon and similar tubes are prone to image lag, better known as ghosting, smearing, burn-in, comet tails, luma trails and luminance blooming. Image lag is visible as noticeable (usually white or colored) trails that appear after a bright object (such as a light or reflection) has moved, leaving a trail that eventually fades into the image. The trail itself does not move, rather it progressively fades as time passes, so areas that were exposed first fade before areas that were later exposed fade. It cannot be avoided or eliminated, as it is inherent to the technology. To what degree the image generated by the vidicon is affected will depend on the properties of the target material used on the vidicon, and the capacitance of the target material (known as the storage effect) as well as the resistance of the electron beam used to scan the target. The higher the capacitance of the target, the higher the charge it can hold and the longer it will take for the trail to disappear. The remmanant charges on the target eventually dissipate making the trail disappear.

The electron gun from an RCA Vidicon camera tube.

Plumbicon (1963)

Plumbicon is a registered trademark of Philips from 1963, for its lead(II) oxide (PbO) target vidicons. Used frequently in broadcast camera applications, these tubes have low output, but a high signal-to-noise ratio. They have excellent resolution compared to image orthicons, but lack the artificially sharp edges of IO tubes, which cause some of the viewing audience to perceive them as softer. CBS Labs invented the first outboard edge enhancement circuits to sharpen the edges of Plumbicon generated images. Philips received the 1966 Technology & Engineering Emmy Award for the Plumbicon.

Schematic of a Plumbicon tube. (This image is schematic, not to scale; a Plumbicon has the same shape as a vidicon.)

Compared to Saticons, Plumbicons have much higher resistance to burn-in, and comet and trailing artifacts from bright lights in the shot. Saticons though, usually have slightly higher resolution. After 1980, and the introduction of the diode-gun Plumbicon tube, the resolution of both types was so high, compared to the maximum limits of the broadcasting standard, that the Saticon's resolution advantage became moot. While broadcast cameras migrated to solid-state charge-coupled devices, Plumbicon tubes remained a staple imaging device in the medical field. High resolution Plumbicons were made for the HD-MAC standard.

Until 2016, Narragansett Imaging was the last company making Plumbicons, using factories Philips built in Rhode Island, USA. While still a part of Philips, the company purchased EEV's (English Electric Valve) lead oxide camera tube business, and gained a monopoly in lead-oxide tube production.

Saticon (1973)

Saticon is a registered trademark of Hitachi from 1973, also produced by Thomson and Sony. It was developed in a joint effort by Hitachi and NHK Science & Technology Research Laboratories (NHK is The Japan Broadcasting Corporation). Its surface consists of selenium with trace amounts of arsenic and tellurium added (SeAsTe) to make the signal more stable. SAT in the name is derived from (SeAsTe). Saticon tubes have an average light sensitivity equivalent to that of 64 ASA film. A high-gain avalanche rushing amorphous photoconductor (HARP) can be used to increase light sensitivity to up to 10 times that of conventional saticons. Saticons were made for the Sony HDVS system, used to produce early analog high-definition television using Multiple sub-Nyquist sampling encoding.

Pasecon (1972)

Originally developed by Toshiba in 1972 as chalnicon, Pasecon is a registered trademark of Heimann GmbH from 1977. Its surface consists of cadmium selenide trioxide (CdSeO3). Due to its wide spectral response, it is labelled as panchromatic selenium vidicon, hence the acronym 'pasecon'.

Newvicon (1973)

Newvicon is a registered trademark of Matsushita from 1973. The Newvicon tubes were characterized by high light sensitivity. Its surface consists of a combination of zinc selenide (ZnSe) and zinc cadmium Telluride (ZnCdTe).

Trinicon (1971)

Trinicon is a registered trademark of Sony from 1971. It uses a vertically striped RGB color filter over the faceplate of an otherwise standard vidicon imaging tube to segment the scan into corresponding red, green and blue segments. Only one tube was used in the camera, instead of a tube for each color, as was standard for color cameras used in television broadcasting. It is used mostly in low-end consumer cameras, such as the HVC-2200 and HVC-2400 models, though Sony also used it in some moderate cost professional cameras in the 1980s, such as the DXC-1800 and BVP-1 models.

Although the idea of using color stripe filters over the target was not new, the Trinicon was the only tube to use the primary RGB colors. This necessitated an additional electrode buried in the target to detect where the scanning electron beam was relative to the stripe filter. Previous color stripe systems had used colors where the color circuitry was able to separate the colors purely from the relative amplitudes of the signals. As a result, the Trinicon featured a larger dynamic range of operation.

Sony later combined the Saticon tube with the Trinicon's RGB color filter, providing low-light sensitivity and superior color. This type of tube was known as the SMF Trinicon tube, or Saticon Mixed Field. SMF Trinicon tubes were used in the HVC-2800 and HVC-2500 consumer cameras, as well as the first Betamovie camcorders.

Light biasing

All the vidicon type tubes except the vidicon itself were able to use a light biasing technique to improve the sensitivity and contrast. The photosensitive target in these tubes suffered from the limitation that the light level had to rise to a particular level before any video output resulted. Light biasing was a method whereby the photosensitive target was illuminated from a light source just enough that no appreciable output was obtained, but such that a slight increase in light level from the scene was enough to provide discernible output. The light came from either an illuminator mounted around the target, or in more professional cameras from a light source on the base of the tube and guided to the target by light piping. The technique would not work with the baseline vidicon tube because it suffered from the limitation that as the target was fundamentally an insulator, the constant low light level built up a charge which would manifest itself as a form of fogging. The other types had semiconducting targets which did not have this problem.

Early color cameras used the obvious technique of using separate red, green and blue image tubes in conjunction with a color separator, a technique still in use with 3CCD solid state cameras today. It was also possible to construct a color camera that used a single image tube. One technique has already been described (Trinicon above). A more common technique and a simpler one from the tube construction standpoint was to overlay the photosensitive target with a color striped filter having a fine pattern of vertical stripes of green, cyan and clear filters (i.e. green; green and blue; and green, blue and red) repeating across the target. The advantage of this arrangement was that for virtually every color, the video level of the green component was always less than the cyan, and similarly the cyan was always less than the white. Thus the contributing images could be separated without any reference electrodes in the tube. If the three levels were the same, then that part of the scene was green. This method suffered from the disadvantage that the light levels under the three filters were almost certain to be different, with the green filter passing not more than one third of the available light.

Variations on this scheme exist, the principal one being to use two filters with color stripes overlaid such that the colors form vertically oriented lozenge shapes overlaying the target. The method of extracting the color is similar however.

Field-sequential color system

During the 1930s and 1940s, field-sequential color systems were developed which used synchronized motor-driven color-filter disks at the camera's image tube and at the television receiver. Each disk consisted of red, blue, and green transparent color filters. In the camera, the disk was in the optical path, and in the receiver, it was in front of the CRT. Disk rotation was synchronized with vertical scanning so that each vertical scan in sequence was for a different primary color. This method allowed regular black-and-white image tubes and CRTs to generate and display color images. A field-sequential system developed by Peter Goldmark for CBS was demonstrated to the press on September 4, 1940, and was first shown to the general public on January 12, 1950. Guillermo González Camarena independently developed a field-sequential color disk system in Mexico in the early 1940s, for which he requested a patent in Mexico on August 19 of 1940 and in the US in 1941. Gonzalez Camarena produced his color television system in his laboratory Gon-Cam for the Mexican market and exported it to the Columbia College of Chicago, who regarded it as the best system in the world.

The phenomenon known as magnetic focusing was discovered by A. A. Campbell-Swinton in 1896, he found that a longitudinal magnetic field generated by an axial coil can focus an electron beam. This phenomenon was immediately corroborated by J. A. Fleming, and Hans Busch gave a complete mathematical interpretation in 1926.

Diagrams in this article show that the focus coil surrounds the camera tube; it is much longer than the focus coils for earlier TV CRTs. Camera-tube focus coils, by themselves, have essentially parallel lines of force, very different from the localized semi-toroidal magnetic field geometry inside a TV receiver CRT focus coil. The latter is essentially a magnetic lens; it focuses the "crossover" (between the CRT's cathode and G1 electrode, where the electrons pinch together and diverge again) onto the screen.

The electron optics of camera tubes differ considerably. Electrons inside these long focus coils take helical paths as they travel along the length of the tube. The center (think local axis) of one of those helices is like a line of force of the magnetic field. While the electrons are traveling, the helices essentially don't matter. Assuming that they start from a point, the electrons will focus to a point again at a distance determined by the strength of the field. Focusing a tube with this kind of coil is simply a matter of trimming the coil's current. In effect, the electrons travel along the lines of force, although helically, in detail.

These focus coils are essentially as long as the tubes themselves, and surround the deflection yoke (coils). Deflection fields bend the lines of force (with negligible defocusing), and the electrons follow the lines of force.

In a conventional magnetically deflected CRT, such as in a TV receiver or computer monitor, basically the vertical deflection coils are equivalent to coils wound around an horizontal axis. That axis is perpendicular to the neck of the tube; lines of force are basically horizontal. (In detail, coils in a deflection yoke extend some distance beyond the neck of the tube, and lie close to the flare of the bulb; they have a truly distinctive appearance.)

In a magnetically focused camera tube (there are electrostatically focused vidicons), the vertical deflection coils are above and below the tube, instead of being on both sides of it. One might say that this sort of deflection starts to create S-bends in the lines of force, but doesn't become anywhere near to that extreme.

The size of video camera tubes is simply the overall outside diameter of the glass envelope. This differs from the size of the sensitive area of the target which is typically two thirds of the size of the overall diameter. Tube sizes are always expressed in inches for historical reasons. A one-inch camera tube has a sensitive area of approximately two thirds of an inch on the diagonal or about 16 mm.

Although the video camera tube is now technologically obsolete, the size of solid-state image sensors is still expressed as the equivalent size of a camera tube. For this purpose a new term was coined and it is known as the optical format. The optical format is approximately the true diagonal of the sensor multiplied by 3/2. The result is expressed in inches and is usually (though not always) rounded to a convenient fraction - hence the approximation. For instance, a 6.4 mm × 4.8 mm(0.25 in × 0.19 in) sensor has a diagonal of 8.0 mm (0.31 in) and therefore an optical format of 8.0*3/2=12 mm (0.47 in), which is rounded to the convenient imperial fraction of 12 inch (1.3 cm). The parameter is also the source of the "Four Thirds" in the Four Thirds system and its Micro Four Thirds extension—the imaging area of the sensor in these cameras is approximately that of a 43-inch (3.4 cm) video-camera tube at approximately 22 millimetres (0.87 in).

Although the optical format size bears no relationship to any physical parameter of the sensor, its use means that a lens that would have been used with (say) a four thirds inch camera tube will give roughly the same angle of view when used with a solid-state sensor with an optical format of four thirds of an inch.

The lifespan of videotube technology reached as far as the 90s, when high definition, 1035-line videotubes were used in the early MUSE HD broadcasting system. While CCDs were tested for this application, as of 1993 broadcasters still found them inadequate due to issues achieving the necessary high resolution without compromising image quality with undesirable side-effects.

Modern charge-coupled device (CCD) and CMOS-based sensors offer many advantages over their tube counterparts. These include a lack of image lag, high overall picture quality, high light sensitivity and dynamic range, a better signal-to-noise ratio and significantly higher reliability and ruggedness. Other advantages include the elimination of the respective high and low-voltage power supplies required for the electron beam and heater filament, elimination of the drive circuitry for the focusing coils, no warm-up time and a significantly lower overall power consumption. Despite these advantages, acceptance and incorporation of solid-state sensors into television and video cameras was not immediate. Early sensors were of lower resolution and performance than picture tubes, and were initially relegated to consumer-grade video recording equipment.

Also, video tubes had progressed to a high standard of quality and were standard issue equipment to networks and production entities. Those entities had a substantial investment in not only tube cameras, but also in the ancillary equipment needed to correctly process tube-derived video. A switch-over to solid-state image sensors rendered much of that equipment (and the investments behind it) obsolete and required new equipment optimized to work well with solid-state sensors, just as the old equipment was optimized for tube-sourced video.

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Video camera tube
Video camera tube Language Watch Edit 160 160 Redirected from Vidicon Video camera tubes were devices based on the cathode ray tube that were used in television cameras to capture television images prior to the introduction of charge coupled device CCD image sensors in the 1980s 1 2 3 Several different types of tubes were in use from the early 1930s and as late as the 1990s vidicon tube 2 3 inch 17 mm in diameter A display of a variety of early experimental video camera tubes from 1954 with Vladimir K Zworykin who invented the iconoscope In these tubes the cathode ray was scanned across an image of the scene to be broadcast The resultant current was dependent on the brightness of the image on the target The size of the striking ray was tiny compared to the size of the target allowing 483 horizontal scan lines per image in the NTSC format 576 lines in PAL 4 and as many as 1035 lines in HiVision Contents 1 Cathode ray tube 2 Early research 3 Image dissector 3 1 Operation 4 Iconoscope 5 Super Emitron and image iconoscope 5 1 Operation 6 Orthicon and CPS Emitron 7 Image orthicon 7 1 Operation 7 2 Dark halo 8 Vidicon 8 1 Plumbicon 1963 8 2 Saticon 1973 8 3 Pasecon 1972 8 4 Newvicon 1973 8 5 Trinicon 1971 8 6 Light biasing 9 Color cameras 9 1 Field sequential color system 10 Magnetic focusing in typical camera tubes 11 Size 12 Late use and decline 13 See also 14 References 15 External linksCathode ray tube EditMain article Cathode ray tube Any vacuum tube which operates using a focused beam of electrons originally called cathode rays is known as a cathode ray tube CRT These are usually seen as display devices as used in older i e non flat panel television receivers and computer displays The camera pickup tubes described in this article are also CRTs but they display no image 5 Early research EditIn June 1908 the scientific journal Nature published a letter in which Alan Archibald Campbell Swinton fellow of the Royal Society UK discussed how a fully electronic television system could be realized by using cathode ray tubes or Braun tubes after their inventor Karl Braun as both imaging and display devices 6 He noted that the real difficulties lie in devising an efficient transmitter and that it was possible that no photoelectric phenomenon at present known will provide what is required 7 A cathode ray tube was successfully demonstrated as a displaying device by the German Professor Max Dieckmann in 1906 his experimental results were published by the journal Scientific American in 1909 8 Campbell Swinton later expanded on his vision in a presidential address given to the Rontgen Society in November 1911 The photoelectric screen in the proposed transmitting device was a mosaic of isolated rubidium cubes 9 10 His concept for a fully electronic television system was later popularized by Hugo Gernsback as the Campbell Swinton Electronic Scanning System in the August 1915 issue of the popular magazine Electrical Experimenter 11 12 13 In a letter to Nature published in October 1926 Campbell Swinton also announced the results of some not very successful experiments he had conducted with G M Minchin and J C M Stanton They had attempted to generate an electrical signal by projecting an image onto a selenium coated metal plate that was simultaneously scanned by a cathode ray beam 14 15 These experiments were conducted before March 1914 when Minchin died 16 but they were later repeated by two different teams in 1937 by H Miller and J W Strange from EMI 17 and by H Iams and A Rose from RCA 18 Both teams succeeded in transmitting very faint images with the original Campbell Swinton s selenium coated plate but much better images were obtained when the metal plate was covered with zinc sulphide or selenide 17 or with aluminum or zirconium oxide treated with caesium 18 These experiments would form the base of the future vidicon A description of a CRT imaging device also appeared in a patent application filed by Edvard Gustav Schoultz in France in August 1921 and published in 1922 19 although a working device was not demonstrated until some years later 18 Image dissector Edit Farnsworth image dissector tube from 1931 Main article Image dissector An image dissector is a camera tube that creates an electron image of a scene from photocathode emissions electrons which pass through a scanning aperture to an anode which serves as an electron detector 20 21 Among the first to design such a device were German inventors Max Dieckmann and Rudolf Hell 22 23 who had titled their 1925 patent application Lichtelektrische Bildzerlegerrohre fur Fernseher Photoelectric Image Dissector Tube for Television 24 The term may apply specifically to a dissector tube employing magnetic fields to keep the electron image in focus 21 an element lacking in Dieckmann and Hell s design and in the early dissector tubes built by American inventor Philo Farnsworth 22 25 Dieckmann and Hell submitted their application to the German patent office in April 1925 and a patent was issued in October 1927 24 Their experiments on the image dissector were announced in the volume 8 September 1927 of the popular magazine Discovery 26 27 and in the May 1928 issue of the magazine Popular Radio 28 However they never transmitted a clear and well focused image with such a tube citation needed In January 1927 American inventor and television pioneer Philo T Farnsworth applied for a patent for his Television System that included a device for the conversion and dissecting of light 25 Its first moving image was successfully transmitted on September 7 of 1927 29 and a patent was issued in 1930 25 Farnsworth quickly made improvements to the device among them introducing an electron multiplier made of nickel 30 31 and using a longitudinal magnetic field in order to sharply focus the electron image 32 The improved device was demonstrated to the press in early September 1928 22 33 34 The introduction of a multipactor in October 1933 35 36 and a multi dynode electron multiplier in 1937 37 38 made Farnsworth s image dissector the first practical version of a fully electronic imaging device for television 39 Unfortunately it had very poor light sensitivity and was therefore primarily useful only where illumination was exceptionally high typically over 685 cd m2 40 41 42 However it was ideal for industrial applications such as monitoring the bright interior of an industrial furnace Due to their poor light sensitivity image dissectors were rarely used in television broadcasting except to scan film and other transparencies citation needed In April 1933 Farnsworth submitted a patent application also entitled Image Dissector but which actually detailed a CRT type camera tube 43 This is among the first patents to propose the use of a low velocity scanning beam and RCA had to buy it in order to sell image orthicon tubes to the general public 44 However Farnsworth never transmitted a clear and well focused image with such a tube 45 46 Operation Edit The optical system of the image dissector focuses an image onto a photocathode mounted inside a high vacuum As light strikes the photocathode electrons are emitted in proportion to the intensity of the light see photoelectric effect The entire electron image is deflected and a scanning aperture permits only those electrons emanating from a very small area of the photocathode to be captured by the detector at any given time The output from the detector is an electric current whose magnitude is a measure of the brightness of the corresponding area of the image The electron image is periodically deflected horizontally and vertically raster scanning such that the entire image is read by the detector many times per second producing an electrical signal that can be conveyed to a display device such as a CRT monitor to reproduce the image 20 21 The image dissector has no charge storage characteristic the vast majority of electrons emitted by the photocathode are excluded by the scanning aperture 23 and thus wasted rather than being stored on a photo sensitive target as in the iconoscope or image orthicon see below which largely accounts for its low light sensitivity Iconoscope Edit Zworykin holding an iconoscope tube Diagram of the iconoscope from Zworykin s 1931 patent Main article Iconoscope An iconoscope is a camera tube that projects an image on a special charge storage plate containing a mosaic of electrically isolated photosensitive granules separated from a common plate by a thin layer of isolating material somewhat analogous to the human eye s retina and its arrangement of photoreceptors Each photosensitive granule constitutes a tiny capacitor that accumulates and stores electrical charge in response to the light striking it An electron beam periodically sweeps across the plate effectively scanning the stored image and discharging each capacitor in turn such that the electrical output from each capacitor is proportional to the average intensity of the light striking it between each discharge event 47 48 After Hungarian engineer Kalman Tihanyi studied Maxwell s equations he discovered a new hitherto unknown physical phenomenon which led to a break through in the development of electronic imaging devices He named the new phenomenon as charge storage principle further information Charge storage principle The problem of low sensitivity to light resulting in low electrical output from transmitting or camera tubes would be solved with the introduction of charge storage technology by the Hungarian engineer Kalman Tihanyi in the beginning of 1925 49 His solution was a camera tube that accumulated and stored electrical charges photoelectrons within the tube throughout each scanning cycle The device was first described in a patent application he filed in Hungary in March 1926 for a television system he dubbed Radioskop 50 After further refinements included in a 1928 patent application 49 Tihanyi s patent was declared void in Great Britain in 1930 51 and so he applied for patents in the United States Tihanyi s charge storage idea remains a basic principle in the design of imaging devices for television to the present day In 1923 while employed by the Westinghouse Electric Corporation in Pittsburgh Pennsylvania Russian born American engineer Vladimir Zworykin presented a project for a totally electronic television system to the company s general manager 52 53 In July 1925 Zworykin submitted a patent application titled Television System that included a charge storage plate constructed of a thin layer of isolating material aluminum oxide sandwiched between a screen 300 mesh and a colloidal deposit of photoelectric material potassium hydride consisting of isolated globules 54 The following description can be read between lines 1 and 9 in page 2 The photoelectric material such as potassium hydride is evaporated on the aluminum oxide or other insulating medium and treated so as to form a colloidal deposit of potassium hydride consisting of minute globules Each globule is very active photoelectrically and constitutes to all intents and purposes a minute individual photoelectric cell Its first image was transmitted in late summer of 1925 55 and a patent was issued in 1928 54 However the quality of the transmitted image failed to impress H P Davis the general manager of Westinghouse and Zworykin was asked to work on something useful 55 A patent for a television system was also filed by Zworykin in 1923 but this filing is not a definitive reference because extensive revisions were done before a patent was issued fifteen years later 44 and the file itself was divided into two patents in 1931 56 57 The first practical iconoscope was constructed in 1931 by Sanford Essig when he accidentally left a silvered mica sheet in the oven too long Upon examination with a microscope he noticed that the silver layer had broken up into a myriad of tiny isolated silver globules 58 He also noticed that the tiny dimension of the silver droplets would enhance the image resolution of the iconoscope by a quantum leap 59 As head of television development at Radio Corporation of America RCA Zworykin submitted a patent application in November 1931 and it was issued in 1935 48 Nevertheless Zworykin s team was not the only engineering group working on devices that used a charge storage plate In 1932 the EMI engineers Tedham and McGee under the supervision of Isaac Shoenberg applied for a patent for a new device they dubbed the Emitron 60 A 405 line broadcasting service employing the Emitron began at studios in Alexandra Palace in 1936 and patents were issued in the United Kingdom in 1934 and in the US in 1937 61 The iconoscope was presented to the general public at a press conference in June 1933 62 and two detailed technical papers were published in September and October of the same year 63 64 Unlike the Farnsworth image dissector the Zworykin iconoscope was much more sensitive useful with an illumination on the target between 4ft c 43lx and 20ft c 215lx It was also easier to manufacture and produced a very clear image citation needed The iconoscope was the primary camera tube used by RCA broadcasting from 1936 until 1946 when it was replaced by the image orthicon tube 65 66 Super Emitron and image iconoscope EditThe original iconoscope was noisy had a high ratio of interference to signal and ultimately gave disappointing results especially when compared to the high definition mechanical scanning systems then becoming available 67 68 The EMI team under the supervision of Isaac Shoenberg analyzed how the Emitron or iconoscope produces an electronic signal and concluded that its real efficiency was only about 5 of the theoretical maximum This is because secondary electrons released from the mosaic of the charge storage plate when the scanning beam sweeps across it may be attracted back to the positively charged mosaic thus neutralizing many of the stored charges 69 Lubszynski Rodda and McGee realized that the best solution was to separate the photo emission function from the charge storage one and so communicated their results to Zworykin 68 69 The new video camera tube developed by Lubszynski Rodda and McGee in 1934 was dubbed the super Emitron This tube is a combination of the image dissector and the Emitron It has an efficient photocathode that transforms the scene light into an electron image the latter is then accelerated towards a target specially prepared for the emission of secondary electrons Each individual electron from the electron image produces several secondary electrons after reaching the target so that an amplification effect is produced The target is constructed of a mosaic of electrically isolated metallic granules separated from a common plate by a thin layer of isolating material so that the positive charge resulting from the secondary emission is stored in the granules Finally an electron beam periodically sweeps across the target effectively scanning the stored image discharging each granule and producing an electronic signal like in the iconoscope 70 71 72 The super Emitron was between ten and fifteen times more sensitive than the original Emitron and iconoscope tubes and in some cases this ratio was considerably greater 69 It was used for an outside broadcast by the BBC for the first time on Armistice Day 1937 when the general public could watch in a television set how the King laid a wreath at the Cenotaph This was the first time that anyone could broadcast a live street scene from cameras installed on the roof of neighboring buildings 73 On the other hand in 1934 Zworykin shared some patent rights with the German licensee company Telefunken 74 The image iconoscope Superikonoskop in Germany was produced as a result of the collaboration This tube is essentially identical to the super Emitron but the target is constructed of a thin layer of isolating material placed on top of a conductive base the mosaic of metallic granules is missing The production and commercialization of the super Emitron and image iconoscope in Europe were not affected by the patent war between Zworykin and Farnsworth because Dieckmann and Hell had priority in Germany for the invention of the image dissector having submitted a patent application for their Lichtelektrische Bildzerlegerrohre fur Fernseher Photoelectric Image Dissector Tube for Television in Germany in 1925 24 two years before Farnsworth did the same in the United States 25 The image iconoscope Superikonoskop became the industrial standard for public broadcasting in Europe from 1936 until 1960 when it was replaced by the vidicon and plumbicon tubes Indeed it was the representative of the European tradition in electronic tubes competing against the American tradition represented by the image orthicon 75 76 The German company Heimann produced the Superikonoskop for the 1936 Berlin Olympic Games 77 78 later Heimann also produced and commercialized it from 1940 to 1955 79 finally the Dutch company Philips produced and commercialized the image iconoscope and multicon from 1952 to 1958 76 80 Operation Edit The super Emitron is a combination of the image dissector and the Emitron The scene image is projected onto an efficient continuous film semitransparent photocathode that transforms the scene light into a light emitted electron image the latter is then accelerated and focused via electromagnetic fields towards a target specially prepared for the emission of secondary electrons Each individual electron from the electron image produces several secondary electrons after reaching the target so that an amplification effect is produced and the resulting positive charge is proportional to the integrated intensity of the scene light The target is constructed of a mosaic of electrically isolated metallic granules separated from a common plate by a thin layer of isolating material so that the positive charge resulting from the secondary emission is stored in the capacitor formed by the metallic granule and the common plate Finally an electron beam periodically sweeps across the target effectively scanning the stored image and discharging each capacitor in turn such that the electrical output from each capacitor is proportional to the average intensity of the scene light between each discharge event as in the iconoscope 70 71 72 The image iconoscope is essentially identical to the super Emitron but the target is constructed of a thin layer of isolating material placed on top of a conductive base the mosaic of metallic granules is missing Therefore secondary electrons are emitted from the surface of the isolating material when the electron image reaches the target and the resulting positive charges are stored directly onto the surface of the isolated material 75 Orthicon and CPS Emitron EditThe original iconoscope was very noisy 67 due to the secondary electrons released from the photoelectric mosaic of the charge storage plate when the scanning beam swept it across 69 An obvious solution was to scan the mosaic with a low velocity electron beam which produced less energy in the neighborhood of the plate such that no secondary electrons were emitted at all That is an image is projected onto the photoelectric mosaic of a charge storage plate so that positive charges are produced and stored there due to photo emission and capacitance respectively These stored charges are then gently discharged by a low velocity electron scanning beam preventing the emission of secondary electrons 81 82 Not all the electrons in the scanning beam may be absorbed in the mosaic because the stored positive charges are proportional to the integrated intensity of the scene light The remaining electrons are then deflected back into the anode 43 47 captured by a special grid 83 84 85 or deflected back into an electron multiplier 86 Low velocity scanning beam tubes have several advantages there are low levels of spurious signals and high efficiency of conversion of light into signal so that the signal output is maximum However there are serious problems as well because the electron beam spreads and accelerates in a direction parallel to the target when it scans the image s borders and corners so that it produces secondary electrons and one gets an image that is well focused in the center but blurry in the borders 46 87 Henroteau was among the first inventors to propose in 1929 the use of low velocity electrons for stabilizing the potential of a charge storage plate 88 but Lubszynski and the EMI team were the first engineers in transmitting a clear and well focused image with such a tube 45 Another improvement is the use of a semitransparent charge storage plate The scene image is then projected onto the back side of the plate while the low velocity electron beam scans the photoelectric mosaic at the front side This configurations allows the use of a straight camera tube because the scene to be transmitted the charge storage plate and the electron gun can be aligned one after the other 82 CPS Emitron television camera The first fully functional low velocity scanning beam tube the CPS Emitron was invented and demonstrated by the EMI team under the supervision of Sir Isaac Shoenberg 89 In 1934 the EMI engineers Blumlein and McGee filed for patents for television transmitting systems where a charge storage plate was shielded by a pair of special grids a negative or slightly positive grid lay very close to the plate and a positive one was placed further away 83 84 85 The velocity and energy of the electrons in the scanning beam were reduced to zero by the decelerating electric field generated by this pair of grids and so a low velocity scanning beam tube was obtained 81 90 The EMI team kept working on these devices and Lubszynski discovered in 1936 that a clear image could be produced if the trajectory of the low velocity scanning beam was nearly perpendicular orthogonal to the charge storage plate in a neighborhood of it 45 91 The resulting device was dubbed the cathode potential stabilized Emitron or CPS Emitron 81 92 The industrial production and commercialization of the CPS Emitron had to wait until the end of the second world war 90 93 On the other side of the Atlantic the RCA team led by Albert Rose began working in 1937 on a low velocity scanning beam device they dubbed the orthicon 94 Iams and Rose solved the problem of guiding the beam and keeping it in focus by installing specially designed deflection plates and deflection coils near the charge storage plate to provide a uniform axial magnetic field 46 86 95 The orthicon was the tube used in RCA s television demonstration at the 1939 New York World s Fair 94 its performance was similar to the image iconoscope s one 96 but it was also unstable under sudden flashes of bright light producing the appearance of a large drop of water evaporating slowly over part of the scene 82 Image orthicon Edit Schematic of image orthicon tube A 1960s era RCA Radiotron Image Orthicon TV Camera Tube The image orthicon sometimes abbreviated IO was common in American broadcasting from 1946 until 1968 97 A combination of the image dissector and the orthicon technologies it replaced the iconoscope in the United States which required a great deal of light to work adequately 98 The image orthicon tube was developed at RCA by Albert Rose Paul K Weimer and Harold B Law It represented a considerable advance in the television field and after further development work RCA created original models between 1939 and 1940 99 The National Defense Research Committee entered into a contract with RCA where the NDRC paid for its further development Upon RCA s development of the more sensitive image orthicon tube in 1943 RCA entered into a production contract with the U S Navy the first tubes being delivered in January 1944 100 RCA began production of image orthicons for civilian use in the second quarter of 1946 66 101 While the iconoscope and the intermediate orthicon used capacitance between a multitude of small but discrete light sensitive collectors and an isolated signal plate for reading video information the image orthicon employed direct charge readings from a continuous electronically charged collector The resultant signal was immune to most extraneous signal crosstalk from other parts of the target and could yield extremely detailed images For instance image orthicon cameras were still being used by NASA for capturing Apollo Saturn rockets nearing orbit although the television networks had phased the cameras out Only they could provide sufficient detail 102 An image orthicon camera can take television pictures by candlelight because of the more ordered light sensitive area and the presence of an electron multiplier at the base of the tube which operated as a high efficiency amplifier It also has a logarithmic light sensitivity curve similar to the human eye However it tends to flare in bright light causing a dark halo to be seen around the object this anomaly was referred to as blooming in the broadcast industry when image orthicon tubes were in operation 103 Image orthicons were used extensively in the early color television cameras where the increased sensitivity of the tube was essential to overcome the very inefficient optical system of the camera 103 104 The image orthocon tube was at one point colloquially referred to as an Immy Harry Lubcke the then President of the Academy of Television Arts amp Sciences decided to have their award named after this nickname Since the statuette was female it was feminized into Emmy 105 Operation Edit An image orthicon consists of three parts a photocathode with an image store target a scanner that reads this image an electron gun and a multistage electron multiplier 106 In the image store light falls upon the photocathode which is a photosensitive plate at a very negative potential approx 600 V and is converted into an electron image a principle borrowed from the image dissector This electron rain is then accelerated towards the target a very thin glass plate acting as a semi isolator at ground potential 0 V and passes through a very fine wire mesh nearly 200 wires per cm very near a few hundredths of a cm and parallel to the target acting as a screen grid at a slightly positive voltage approx 2 V Once the image electrons reach the target they cause a splash of electrons by the effect of secondary emission On average each image electron ejects several splash electrons thus adding amplification by secondary emission and these excess electrons are soaked up by the positive mesh effectively removing electrons from the target and causing a positive charge on it in relation to the incident light in the photocathode The result is an image painted in positive charge with the brightest portions having the largest positive charge 107 A sharply focused beam of electrons a cathode ray is generated by the electron gun at ground potential and accelerated by the anode the first dynode of the electron multiplier around the gun at a high positive voltage approx 1500 V Once it exits the electron gun its inertia makes the beam move away from the dynode towards the back side of the target At this point the electrons lose speed and get deflected by the horizontal and vertical deflection coils effectively scanning the target Thanks to the axial magnetic field of the focusing coil this deflection is not in a straight line thus when the electrons reach the target they do so perpendicularly avoiding a sideways component The target is nearly at ground potential with a small positive charge thus when the electrons reach the target at low speed they are absorbed without ejecting more electrons This adds negative charge to the positive charge until the region being scanned reaches some threshold negative charge at which point the scanning electrons are reflected by the negative potential rather than absorbed in this process the target recovers the electrons needed for the next scan These reflected electrons return down the cathode ray tube toward the first dynode of the electron multiplier surrounding the electron gun which is at high potential The number of reflected electrons is a linear measure of the target s original positive charge which in turn is a measure of brightness 108 Dark halo Edit Dark halo around bright rocket flame in television of John Glenn s liftoff of Mercury Atlas 6 in 1962 The mysterious dark orthicon halo around bright objects in an orthicon captured image is based on the fact that the IO relies on the emission of photoelectrons but very bright illumination can produce more of them locally than the device can successfully deal with At a very bright point on a captured image a great preponderance of electrons is ejected from the photosensitive plate So many may be ejected that the corresponding point on the collection mesh can no longer soak them up and thus they fall back to nearby spots on the target instead much as water splashes in a ring when a rock is thrown into it Since the resultant splashed electrons do not contain sufficient energy to eject further electrons where they land they will instead neutralize any positive charge that has been built up in that region Since darker images produce less positive charge on the target the excess electrons deposited by the splash will be read as a dark region by the scanning electron beam citation needed This effect was actually cultivated by tube manufacturers to a certain extent as a small carefully controlled amount of the dark halo has the effect of crispening the visual image due to the contrast effect That is giving the illusion of being more sharply focused than it actually is The later vidicon tube and its descendants see below do not exhibit this effect and so could not be used for broadcast purposes until special detail correction circuitry could be developed 109 Vidicon EditA vidicon tube is a video camera tube design in which the target material is a photoconductor The vidicon was developed in the 1950s at RCA by P K Weimer S V Forgue and R R Goodrich as a simple alternative to the structurally and electrically complex image orthicon citation needed While the initial photoconductor used was selenium other targets including silicon diode arrays have been used 110 Schematic of vidicon tube The vidicon is a storage type camera tube in which a charge density pattern is formed by the imaged scene radiation on a photoconductive surface which is then scanned by a beam of low velocity electrons The fluctuating voltage coupled out to a video amplifier can be used to reproduce the scene being imaged The electrical charge produced by an image will remain in the face plate until it is scanned or until the charge dissipates By using a pyroelectric material such as triglycine sulfate TGS as the target a vidicon sensitive over a broad portion of the infrared spectrum 111 is possible This technology was a precursor to modern microbolometer technology and mainly used in firefighting thermal cameras 112 Prior to the design and construction of the Galileo probe to Jupiter in the late 1970s to early 1980s NASA used vidicon cameras on nearly all the unmanned deep space probes equipped with the remote sensing ability 113 Vidicon tubes were also used aboard the first three Landsat earth imaging satellites launched in 1972 as part of each spacecraft s Return Beam Vidicon RBV imaging system 114 115 116 The Uvicon a UV variant Vidicon was also used by NASA for UV duties 117 Vidicon tubes were popular in 1970s and 1980s after which they were rendered obsolete by solid state image sensors with the charge coupled device CCD and then the CMOS sensor All vidicon and similar tubes are prone to image lag better known as ghosting smearing burn in comet tails luma trails and luminance blooming Image lag is visible as noticeable usually white or colored trails that appear after a bright object such as a light or reflection has moved leaving a trail that eventually fades into the image The trail itself does not move rather it progressively fades as time passes so areas that were exposed first fade before areas that were later exposed fade It cannot be avoided or eliminated as it is inherent to the technology To what degree the image generated by the vidicon is affected will depend on the properties of the target material used on the vidicon and the capacitance of the target material known as the storage effect as well as the resistance of the electron beam used to scan the target The higher the capacitance of the target the higher the charge it can hold and the longer it will take for the trail to disappear The remmanant charges on the target eventually dissipate making the trail disappear 118 The electron gun from an RCA Vidicon camera tube Plumbicon 1963 Edit Plumbicon is a registered trademark of Philips from 1963 for its lead II oxide PbO target vidicons 119 Used frequently in broadcast camera applications these tubes have low output but a high signal to noise ratio They have excellent resolution compared to image orthicons but lack the artificially sharp edges of IO tubes which cause some of the viewing audience to perceive them as softer CBS Labs invented the first outboard edge enhancement circuits to sharpen the edges of Plumbicon generated images 120 121 122 Philips received the 1966 Technology amp Engineering Emmy Award for the Plumbicon 123 Schematic of a Plumbicon tube This image is schematic not to scale a Plumbicon has the same shape as a vidicon Compared to Saticons Plumbicons have much higher resistance to burn in and comet and trailing artifacts from bright lights in the shot Saticons though usually have slightly higher resolution After 1980 and the introduction of the diode gun Plumbicon tube the resolution of both types was so high compared to the maximum limits of the broadcasting standard that the Saticon s resolution advantage became moot While broadcast cameras migrated to solid state charge coupled devices Plumbicon tubes remained a staple imaging device in the medical field 120 121 122 High resolution Plumbicons were made for the HD MAC standard 124 Until 2016 Narragansett Imaging was the last company making Plumbicons using factories Philips built in Rhode Island USA While still a part of Philips the company purchased EEV s English Electric Valve lead oxide camera tube business and gained a monopoly in lead oxide tube production 120 121 122 Saticon 1973 Edit Saticon is a registered trademark of Hitachi from 1973 also produced by Thomson and Sony It was developed in a joint effort by Hitachi and NHK Science amp Technology Research Laboratories NHK is The Japan Broadcasting Corporation Its surface consists of selenium with trace amounts of arsenic and tellurium added SeAsTe to make the signal more stable SAT in the name is derived from SeAsTe 125 Saticon tubes have an average light sensitivity equivalent to that of 64 ASA film 126 A high gain avalanche rushing amorphous photoconductor HARP can be used to increase light sensitivity to up to 10 times that of conventional saticons 127 Saticons were made for the Sony HDVS system used to produce early analog high definition television using Multiple sub Nyquist sampling encoding 126 Pasecon 1972 Edit Originally developed by Toshiba in 1972 as chalnicon Pasecon is a registered trademark of Heimann GmbH from 1977 Its surface consists of cadmium selenide trioxide CdSeO3 Due to its wide spectral response it is labelled as panchromatic selenium vidicon hence the acronym pasecon 125 128 129 Newvicon 1973 Edit Newvicon is a registered trademark of Matsushita from 1973 130 The Newvicon tubes were characterized by high light sensitivity Its surface consists of a combination of zinc selenide ZnSe and zinc cadmium Telluride ZnCdTe 125 Trinicon 1971 Edit Trinicon is a registered trademark of Sony from 1971 131 It uses a vertically striped RGB color filter over the faceplate of an otherwise standard vidicon imaging tube to segment the scan into corresponding red green and blue segments Only one tube was used in the camera instead of a tube for each color as was standard for color cameras used in television broadcasting It is used mostly in low end consumer cameras such as the HVC 2200 and HVC 2400 models though Sony also used it in some moderate cost professional cameras in the 1980s such as the DXC 1800 and BVP 1 models 132 Although the idea of using color stripe filters over the target was not new the Trinicon was the only tube to use the primary RGB colors This necessitated an additional electrode buried in the target to detect where the scanning electron beam was relative to the stripe filter Previous color stripe systems had used colors where the color circuitry was able to separate the colors purely from the relative amplitudes of the signals As a result the Trinicon featured a larger dynamic range of operation Sony later combined the Saticon tube with the Trinicon s RGB color filter providing low light sensitivity and superior color This type of tube was known as the SMF Trinicon tube or Saticon Mixed Field SMF Trinicon tubes were used in the HVC 2800 and HVC 2500 consumer cameras as well as the first Betamovie camcorders Light biasing Edit All the vidicon type tubes except the vidicon itself were able to use a light biasing technique to improve the sensitivity and contrast The photosensitive target in these tubes suffered from the limitation that the light level had to rise to a particular level before any video output resulted Light biasing was a method whereby the photosensitive target was illuminated from a light source just enough that no appreciable output was obtained but such that a slight increase in light level from the scene was enough to provide discernible output The light came from either an illuminator mounted around the target or in more professional cameras from a light source on the base of the tube and guided to the target by light piping The technique would not work with the baseline vidicon tube because it suffered from the limitation that as the target was fundamentally an insulator the constant low light level built up a charge which would manifest itself as a form of fogging The other types had semiconducting targets which did not have this problem Color cameras EditEarly color cameras used the obvious technique of using separate red green and blue image tubes in conjunction with a color separator a technique still in use with 3CCD solid state cameras today It was also possible to construct a color camera that used a single image tube One technique has already been described Trinicon above A more common technique and a simpler one from the tube construction standpoint was to overlay the photosensitive target with a color striped filter having a fine pattern of vertical stripes of green cyan and clear filters i e green green and blue and green blue and red repeating across the target The advantage of this arrangement was that for virtually every color the video level of the green component was always less than the cyan and similarly the cyan was always less than the white Thus the contributing images could be separated without any reference electrodes in the tube If the three levels were the same then that part of the scene was green This method suffered from the disadvantage that the light levels under the three filters were almost certain to be different with the green filter passing not more than one third of the available light Variations on this scheme exist the principal one being to use two filters with color stripes overlaid such that the colors form vertically oriented lozenge shapes overlaying the target The method of extracting the color is similar however Field sequential color system Edit During the 1930s and 1940s field sequential color systems were developed which used synchronized motor driven color filter disks at the camera s image tube and at the television receiver Each disk consisted of red blue and green transparent color filters In the camera the disk was in the optical path and in the receiver it was in front of the CRT Disk rotation was synchronized with vertical scanning so that each vertical scan in sequence was for a different primary color This method allowed regular black and white image tubes and CRTs to generate and display color images A field sequential system developed by Peter Goldmark for CBS was demonstrated to the press on September 4 1940 133 and was first shown to the general public on January 12 1950 134 Guillermo Gonzalez Camarena independently developed a field sequential color disk system in Mexico in the early 1940s for which he requested a patent in Mexico on August 19 of 1940 and in the US in 1941 135 Gonzalez Camarena produced his color television system in his laboratory Gon Cam for the Mexican market and exported it to the Columbia College of Chicago who regarded it as the best system in the world 136 137 Magnetic focusing in typical camera tubes EditThe phenomenon known as magnetic focusing was discovered by A A Campbell Swinton in 1896 he found that a longitudinal magnetic field generated by an axial coil can focus an electron beam 138 This phenomenon was immediately corroborated by J A Fleming and Hans Busch gave a complete mathematical interpretation in 1926 139 Diagrams in this article show that the focus coil surrounds the camera tube it is much longer than the focus coils for earlier TV CRTs Camera tube focus coils by themselves have essentially parallel lines of force very different from the localized semi toroidal magnetic field geometry inside a TV receiver CRT focus coil The latter is essentially a magnetic lens it focuses the crossover between the CRT s cathode and G1 electrode where the electrons pinch together and diverge again onto the screen The electron optics of camera tubes differ considerably Electrons inside these long focus coils take helical paths as they travel along the length of the tube The center think local axis of one of those helices is like a line of force of the magnetic field While the electrons are traveling the helices essentially don t matter Assuming that they start from a point the electrons will focus to a point again at a distance determined by the strength of the field Focusing a tube with this kind of coil is simply a matter of trimming the coil s current In effect the electrons travel along the lines of force although helically in detail These focus coils are essentially as long as the tubes themselves and surround the deflection yoke coils Deflection fields bend the lines of force with negligible defocusing and the electrons follow the lines of force In a conventional magnetically deflected CRT such as in a TV receiver or computer monitor basically the vertical deflection coils are equivalent to coils wound around an horizontal axis That axis is perpendicular to the neck of the tube lines of force are basically horizontal In detail coils in a deflection yoke extend some distance beyond the neck of the tube and lie close to the flare of the bulb they have a truly distinctive appearance In a magnetically focused camera tube there are electrostatically focused vidicons the vertical deflection coils are above and below the tube instead of being on both sides of it One might say that this sort of deflection starts to create S bends in the lines of force but doesn t become anywhere near to that extreme Size EditThe size of video camera tubes is simply the overall outside diameter of the glass envelope This differs from the size of the sensitive area of the target which is typically two thirds of the size of the overall diameter Tube sizes are always expressed in inches for historical reasons A one inch camera tube has a sensitive area of approximately two thirds of an inch on the diagonal or about 16 mm Although the video camera tube is now technologically obsolete the size of solid state image sensors is still expressed as the equivalent size of a camera tube For this purpose a new term was coined and it is known as the optical format The optical format is approximately the true diagonal of the sensor multiplied by 3 2 The result is expressed in inches and is usually though not always rounded to a convenient fraction hence the approximation For instance a 6 4 mm 4 8 mm 0 25 in 0 19 in sensor has a diagonal of 8 0 mm 0 31 in and therefore an optical format of 8 0 3 2 12 mm 0 47 in which is rounded to the convenient imperial fraction of 1 2 inch 1 3 cm The parameter is also the source of the Four Thirds in the Four Thirds system and its Micro Four Thirds extension the imaging area of the sensor in these cameras is approximately that of a 4 3 inch 3 4 cm video camera tube at approximately 22 millimetres 0 87 in 140 Although the optical format size bears no relationship to any physical parameter of the sensor its use means that a lens that would have been used with say a four thirds inch camera tube will give roughly the same angle of view when used with a solid state sensor with an optical format of four thirds of an inch Late use and decline EditThe lifespan of videotube technology reached as far as the 90s when high definition 1035 line videotubes were used in the early MUSE HD broadcasting system While CCDs were tested for this application as of 1993 broadcasters still found them inadequate due to issues achieving the necessary high resolution without compromising image quality with undesirable side effects 141 Modern charge coupled device CCD and CMOS based sensors offer many advantages over their tube counterparts These include a lack of image lag high overall picture quality high light sensitivity and dynamic range a better signal to noise ratio and significantly higher reliability and ruggedness Other advantages include the elimination of the respective high and low voltage power supplies required for the electron beam and heater filament elimination of the drive circuitry for the focusing coils no warm up time and a significantly lower overall power consumption Despite these advantages acceptance and incorporation of solid state sensors into television and video cameras was not immediate Early sensors were of lower resolution and performance than picture tubes and were initially relegated to consumer grade video recording equipment 141 Also video tubes had progressed to a high standard of quality and were standard issue equipment to networks and production entities Those entities had a substantial investment in not only tube cameras but also in the ancillary equipment needed to correctly process tube derived video A switch over to solid state image sensors rendered much of that equipment and the investments behind it obsolete and required new equipment optimized to work well with solid state sensors just as the old equipment was optimized for tube sourced video See also EditMonoscope Professional video cameraReferences Edit 1980s www digicamhistory com 1984 1985 www digicamhistory com RCA TV Equipment Archive www oldradio com NTSC Lines and refresh rate Cathode ray tube McGraw Hill Concise Encyclopedia of Science amp Technology Third Ed Sybil P Parker ed McGraw Hill Inc 1992 pp 332 333 Campbell Swinton A A 1908 06 18 Distant Electric Vision first paragraph Nature 78 2016 151 Bibcode 1908Natur 78 151S doi 10 1038 078151a0 S2CID 3956737 Campbell Swinton A A 1908 06 18 Distant Electric Vision Nature 78 2016 151 Bibcode 1908Natur 78 151S doi 10 1038 078151a0 S2CID 3956737 Max Dieckmann 1909 07 24 The problem of television a partial solution Scientific American Supplement 68 61 62 doi 10 1038 scientificamerican07241909 61supp Albert Abramson 1955 Electronic Motion Pictures University of California Press p 31 Alexander B Magoun 2007 Television the life story of a technology Greenwood Publishing Group p 12 ISBN 978 0 313 33128 2 rubidium cubes Jr Raymond C Watson 2009 Radar Origins Worldwide History of Its Evolution in 13 Nations Through World War II Trafford Publishing p 26 ISBN 978 1 4269 2110 0 David Sarnoff Collection Television David Sarnoff Library Biography Retrieved 2011 07 20 Bairdtelevision Alan Archivald Campbell Swinton 1863 1930 Biography Retrieved 2010 05 10 Campbell Swinton A A 1926 10 23 Electric Television abstract Nature 118 2973 590 Bibcode 1926Natur 118 590S doi 10 1038 118590a0 S2CID 4081053 Burns R W 1998 Television An International History of the Formative Years The Institute of Electrical Engineers in association with The Science Museum p 123 ISBN 978 0 85296 914 4 News 1914 04 02 Prof G M Minchin F R S Nature 93 2318 115 116 Bibcode 1914Natur 93 115R doi 10 1038 093115a0 a b Miller H amp Strange J W 1938 05 02 The electrical reproduction of images by the photoconductive effect Proceedings of the Physical Society 50 3 374 384 Bibcode 1938PPS 50 374M doi 10 1088 0959 5309 50 3 307 a b c Iams H amp Rose A August 1937 Television Pickup Tubes with Cathode Ray Beam Scanning Proceedings of the Institute of Radio Engineers 25 8 1048 1070 doi 10 1109 JRPROC 1937 228423 S2CID 51668505 Schoultz Edvard Gustav filed 1921 patented 1922 Procede et appareillage pour la transmission des images mobiles a distance Patent No FR 539 613 Office National de la Propriete industrielle Retrieved 2009 07 28 a b Horowitz Paul and Winfield Hill The Art of Electronics Second Edition Cambridge University Press 1989 pp 1000 1001 ISBN 0 521 37095 7 a b c Jack Keith amp Vladimir Tsatsulin 2002 Dictionary of Video and Television Technology Gulf Professional Publishing p 148 ISBN 978 1 878707 99 4 a b c Burns R W 1998 Television An International History of the Formative Years The Institute of Electrical Engineers in association with The Science Museum pp 358 361 ISBN 978 0 85296 914 4 a b Webb Richard C 2005 Tele visionaries the People Behind the Invention of Television John Wiley and Sons p 30 ISBN 978 0 471 71156 8 a b c Dieckmann Max amp Rudolf Hell filed 1925 patented 1927 Lichtelektrische Bildzerlegerroehre fur Fernseher Patent No DE 450 187 Deutsches Reich Reichspatentamt Retrieved 2009 07 28 Check date values in date help a b c d Farnsworth Philo T filed 1927 patented 1930 Television System Patent No 1 773 980 United States Patent Office Retrieved 2009 07 28 Check date values in date help Brittain B J September 1928 Television on the Continent Discovery A Monthly Popular Journal of Knowledge John Murray 8 September 283 285 Hartley John 1999 Uses of television Routledge p 72 ISBN 978 0 415 08509 0 Dieckmann Max May 1928 Cathode Ray Television Popular Radio 1928 May 397 and 406 Postman Neil 1999 03 29 Philo Farnsworth The TIME 100 Scientists amp Thinkers TIME com Archived from the original on May 31 2000 Retrieved 2009 07 28 Farnsworth Philo T filed 1928 patented 1934 Photoelectric Apparatus Patent No 1 970 036 United States Patent Office Retrieved 2010 01 15 Check date values in date help Farnsworth Philo T filed 1928 patented 1939 Television Method Patent No 2 168 768 United States Patent Office Retrieved 2010 01 15 Check date values in date help Farnsworth Philo T filed 1928 patented 1935 Electrical Discharge Apparatus Patent No 1 986 330 United States Patent Office Retrieved 2009 07 29 Check date values in date help Farnsworth Elma Distant Vision Romance and Discovery on an Invisible Frontier Salt Lake City PemberlyKent 1989 pp 108 109 Philo Taylor Farnsworth 1906 1971 The Virtual Museum of the City of San Francisco Archived from the original on June 22 2011 Retrieved 2009 07 15 Farnsworth Philo T filed 1933 patented 1937 Electron Multiplying Device Patent No 2 071 515 United States Patent Office Retrieved 2010 02 22 Farnsworth Philo T filed 1935 patented 1937 Multipactor Phase Control Patent No 2 071 517 United States Patent Office Retrieved 2010 02 22 Farnsworth Philo T filed 1937 patented 1939 Two stage Electron Multiplier Patent No 2 161 620 United States Patent Office Retrieved 2010 02 22 Gardner Bernard C filed 1937 patented 1940 Image Analyzing and Dissecting Tube Patent No 2 200 166 United States Patent Office Retrieved 2010 02 22 Abramson Albert 1987 The History of Television 1880 to 1941 Jefferson NC Albert Abramson p 159 ISBN 0 89950 284 9 ITT Industrial Laboratories December 1964 Vidissector Image Dissector page 1 Tentative Data sheet ITT Archived from the original on 2010 09 15 Retrieved 2010 02 22 ITT Industrial Laboratories December 1964 Vidissector Image Dissector page 2 Tentative Data sheet ITT Archived from the original on 2010 09 15 Retrieved 2010 02 22 ITT Industrial Laboratories December 1964 Vidissector Image Dissector page 3 Tentative Data sheet ITT Archived from the original on 2010 09 15 Retrieved 2010 02 22 a b Farnsworth Philo T filed 1933 patented 1937 reissued 1940 Image Dissector Patent No 2 087 683 United States Patent Office Archived from the original on 2011 07 22 Retrieved 2010 01 10 CS1 maint multiple names authors list link a b Schatzkin Paul The Farnsworth Chronicles Who Invented What and When Retrieved 2010 01 10 a b c Abramson Albert 1995 Zworykin pioneer of television University of Illinois Press p 282 ISBN 978 0 252 02104 6 Retrieved 2010 01 18 a b c Rose Albert amp Iams Harley A September 1939 Television Pickup Tubes Using Low Velocity Electron Beam Scanning Proceedings of the IRE Proceedings of the IRE volume 27 issue 9 27 9 547 555 doi 10 1109 JRPROC 1939 228710 S2CID 51670303 a b Tihanyi Kalman filed in Germany 1928 filed in USA 1929 patented 1939 Television Apparatus Patent No 2 158 259 United States Patent Office Archived from the original on 2011 07 22 Retrieved 2010 01 10 CS1 maint multiple names authors list link a b Zworykin V K filed 1931 patented 1935 Method of and Apparatus for Producing Images of Objects Patent No 2 021 907 United States Patent Office Retrieved 2010 01 10 a b Kalman Tihanyi 1897 1947 IEC Techline permanent dead link International Electrotechnical Commission IEC 2009 07 15 Kalman Tihanyi s 1926 Patent Application Radioskop Memory of the World United Nations Educational Scientific and Cultural Organization UNESCO 2005 retrieved 2009 01 29 Tihanyi Koloman Improvements in television apparatus European Patent Office Patent No GB313456 Convention date UK application 1928 06 11 declared void and published 1930 11 11 retrieved 2013 04 25 Magoun Alexander B Cody George 2006 Vladimir Kosma Zworykin The National Academies Press Retrieved January 25 2018 The Editors of Encyclopaedia Britannica Vladimir Zworykin American Engineer and Inventor Retrieved January 25 2018 a b Zworykin V K filed 1925 patented 1928 Television System Patent No 1 691 324 United States Patent Office Retrieved 2010 01 10 Check date values in date help a b Burns R W 1998 Television An International History of the Formative Years The Institute of Electrical Engineers in association with The Science Museum p 383 ISBN 978 0 85296 914 4 Retrieved 2010 01 10 Zworykin Vladimir K filed 1923 issued 1935 Television System Patent No 2 022 450 United States Patent Office Retrieved 2010 01 10 Check date values in date help Zworykin Vladimir K filed 1923 issued 1938 Television System Patent No 2 141 059 United States Patent Office Retrieved 2010 01 10 Check date values in date help Burns R W 2004 Communications an international history of the formative years The Institute of Electrical Engineers p 534 ISBN 978 0 86341 327 8 Webb Richard C 2005 Tele visionaries the People Behind the Invention of Television John Wiley and Sons p 34 ISBN 978 0 471 71156 8 EMI LTD Tedham William F amp McGee James D filed May 1932 patented 1934 Improvements in or relating to cathode ray tubes and the like Patent No GB 406 353 United Kingdom Intellectual Property Office Retrieved 2010 02 22 Check date values in date help Tedham William F amp McGee James D filed in Great Britain 1932 filed in USA 1933 patented 1937 Cathode Ray Tube Patent No 2 077 422 United States Patent Office Retrieved 2010 01 10 Check date values in date help Lawrence Williams L June 27 1933 Human like eye made by engineers to televise images Iconoscope converts scenes into electrical energy for radio transmission Fast as a movie camera Three million tiny photo cells memorize then pass out pictures Step to home television Developed in ten years work by Dr V K Zworykin who describes it at Chicago New York Times article ISBN 978 0 8240 7782 2 Retrieved 2010 01 10 Zworykin V K September 1933 The Iconoscope America s latest television favourite Wireless World number 33 p 197 ISBN 978 0 8240 7782 2 Retrieved 2010 01 12 Zworykin V K October 1933 Television with cathode ray tubes Journal of the IEE number 73 pp 437 451 ISBN 978 0 8240 7782 2 R C A Officials Continue to Be Vague Concerning Future of Television The Washington Post 1936 11 15 p B2 Missing or empty url help a b Abramson Albert 2003 The history of television 1942 to 2000 McFarland p 18 ISBN 978 0 7864 1220 4 Retrieved 2010 01 10 a b Winston Brian 1986 Misunderstanding media Harvard University Press pp 60 61 ISBN 978 0 674 57663 6 Retrieved 2010 03 09 a b Winston Brian 1998 Media technology and society A history from the telegraph to the Internet Routledge p 105 ISBN 978 0 415 14230 4 Retrieved 2013 02 09 a b c d Alexander Robert Charles 2000 The inventor of stereo the life and works of Alan Dower Blumlein Focal Press pp 217 219 ISBN 978 0 240 51628 8 Retrieved 2010 01 10 a b Lubszynski Hans Gerhard amp Rodda Sydney filed May 1934 patented February 1936 Improvements in or relating to television Patent No GB 442 666 United Kingdom Intellectual Property Office Retrieved 2010 01 15 Check date values in date help a b Lubszynski Hans Gerhard amp Rodda Sydney filed February 1935 patented October 1936 Improvements in and relating to television Patent No GB 455 085 United Kingdom Intellectual Property Office Retrieved 2010 01 15 Check date values in date help a b EMI LTD and Lubszynski Hans Gerhard filed May 1936 patented November 1937 Improvements in or relating to television Patent No GB 475 928 United Kingdom Intellectual Property Office Retrieved 2010 01 15 Check date values in date help Howett Dicky 2006 Television Innovations 50 Technological Developments Kelly Publications p 114 ISBN 978 1 903 05322 5 Retrieved 2013 10 10 Inglis Andrew F 1990 Behind the tube a history of broadcasting technology and business Focal Press p 172 ISBN 978 0 240 80043 1 Retrieved 2010 01 15 a b de Vries M J de Vries Marc Cross Nigel amp Grant Donald P 1993 Design methodology and relationships with science Numero 71 de NATO ASI series Springer p 222 ISBN 978 0 7923 2191 0 Retrieved 2010 01 15 a b Smith Harry July 1953 Multicon A new TV camera tube PDF newspaper article Early Television Foundation and Museum Retrieved 2013 03 12 Gittel Joachim 2008 10 11 Spezialrohren photographic album Jogis Rohrenbude Retrieved 2010 01 15 Early Television Museum TV Camera Tubes German Super Iconoscope 1936 photographic album Early Television Foundation and Museum Archived from the original on 2011 06 17 Retrieved 2010 01 15 Gittel Joachim 2008 10 11 FAR Rohren der Firma Heimann photographic album Jogis Rohrenbude Retrieved 2010 01 15 Philips 1952 to 1958 5854 Image Iconoscope Philips PDF electronic tube handbook Philips Retrieved 2010 01 15 Check date values in date help a b c Burns R W 2000 The life and times of A D Blumlein IET p 181 ISBN 978 0 85296 773 7 Retrieved 2010 03 05 a b c Webb Richard C 2005 Tele visionaries the People Behind the Invention of Television John Wiley and Sons p 65 ISBN 978 0 471 71156 8 a b Blumlein Alan Dower amp McGee James Dwyer filed August 1934 patented May 1936 Improvements in or relating to television transmitting systems Patent No GB 446 661 United Kingdom Intellectual Property Office Retrieved 2010 03 09 Check date values in date help a b McGee James Dwyer filed September 1934 patented May 1936 Improvements in or relating to television transmitting systems Patent No GB 446 664 United Kingdom Intellectual Property Office Retrieved 2010 03 09 Check date values in date help a b Blumlein Alan Dower amp McGee James Dwyer filed in Great Britain August 1934 filed in USA August 1935 patented December 1939 Television Transmitting System Patent No 2 182 578 United States Patent Office Retrieved 2010 03 09 Check date values in date help a b Iams Harley A filed January 1941 patented June 1942 Television Transmitting Tube Patent No 2 288 402 United States Patent Office Retrieved 2010 03 09 Check date values in date help McGee J D November 1950 A review of some television pick up tubes Proceedings of the IEE Part III Radio and Communication Engineering Proceedings of the IEE Part III Radio and Communication Engineering volume 97 issue 50 97 50 380 381 doi 10 1049 pi 3 1950 0073 Retrieved 2013 02 21 Henroteau Francois Charles Pierre filed 1929 patented 1933 Television Patent No 1 903 112 A United States Patent Office Retrieved 2013 01 15 Check date values in date help Sir Isaac Shoenberg British inventor Encyclopaedia Britannica Retrieved 22 July 2020 principal inventor of the first high definition television system a b Edited by McGee J D and Wilcock W L 1960 Advances in Electronics and Electron Physics Volume XII Academic Press p 204 ISBN 978 0 12 014512 6 CS1 maint extra text authors list link Lubszynski Hans Gerhard filed January 1936 patented July 1937 Improvements in and relating to television and like systems Patent No GB 468 965 United Kingdom Intellectual Property Office Retrieved 2010 03 09 Check date values in date help McLean T P amp Schagen P 1979 Electronic imaging Academic Press p 46 and 53 ISBN 978 0 12 485050 7 Retrieved 2010 03 10 EMI 1947 CPS Emitron tube type 5954 Museum of the Broadcast Television Camera Retrieved 2013 03 27 a b Albert Rose Biography IEEE Global History Center Rose Albert filed 1942 patented 1946 Television Transmitting Apparatus and Method of Operation Patent No 2 407 905 United States Patent Office Retrieved 2010 01 15 Check date values in date help Edited by Marton L 1948 Advances in Electronics and Electron Physics Volume 1 Academic Press p 153 ISBN 978 0 12 014501 0 CS1 maint extra text authors list link Abramson Albert The History of Television 1942 to 2000 McFarland 2003 p 124 ISBN 0 7864 1220 8 Staff 1997 2000 Television Microsoft Encarta Online Encyclopedia 2000 Microsoft Corporation Archived from the original on October 4 2009 Retrieved 29 June 2012 Abramson Albert The History of Television 1942 to 2000 McFarland 2003 pp 7 8 ISBN 0 7864 1220 8 Remington Rand Inc v U S 120 F Supp 912 913 1944 aade com Archived January 29 2012 at the Wayback Machine RCA 2P23 One of the earliest image orthicons The University of Alabama Telescopic Tracking of the Apollo Lunar Missions a b dtic mil Westinghouse Non blooming Image Orthicon oai dtic mil Archived 2015 02 20 at the Wayback Machine Non blooming Image Orthicon Parker Sandra August 12 2013 History of the Emmy Statuette Emmys Academy of Television Arts and Sciences Retrieved March 14 2017 roysvintagevideo 741 com 3 image orthicon camera project acmi net au Archived April 4 2004 at the Wayback Machine The Image Orthicon Television Camera Tube c 1940 1960 fazano pro br The Image Converter morpheustechnology com Morpheus Technology 4 5 1 Camera Tubes The RCA Ultricon PDF RCA Retrieved 9 April 2021 Goss A J Nixon R D Watton R Wreathall W M September 2018 Mollicone Richard A Spiro Irving J eds Progress In IR Television Using The Pyroelectric Vidicon Proceedings of the Society of Photo Optical Instrumentation Engineers Infrared Technology X 510 Infrared Technology X 154 doi 10 1117 12 945018 S2CID 111164581 http www fire tics co uk 4428 htm Spacecraft Imaging III First Voyage into the PDS The Planetary Society Retrieved 23 November 2011 Landsat 3 Return Beam Vidicon RBV NASA Space Science Data Coordinated Archive Retrieved July 9 2017 Irons James R Taylor Michael P Rocchio Laura Landsat1 Landsat Science NASA Retrieved March 25 2016 United States Geological Survey August 9 2006 Landsat 2 History Archived from the original on April 28 2016 Retrieved January 16 2007 National Air and Space Museum Detector Uvicon Celescope Smithsonian Institution http www avartifactatlas com artifacts image lag html PLUMBICON Trademark Registration Number 0770662 Serial Number 72173123 a b c History of Narragansett Imaging Narragansett Imaging Narragansett Imaging 2004 Archived from the original on 17 August 2016 Retrieved 29 June 2012 a b c Camera Tubes Narragansett Imaging 2004 Archived from the original on 31 May 2016 Retrieved 29 June 2012 a b c Plumbicon Broadcast Tubes Narragansett Imaging 2004 Archived from the original on 15 July 2016 Retrieved 29 June 2012 Emmy 1966 Technology amp Engineering Emmy Award PDF https tech ebu ch docs techreview trev 254 tejerina pdf a b c Dhake A M 1999 05 01 TV and Video Engineering Tata McGraw Hill Education ISBN 9780074601051 a b Cianci Philip J January 10 2014 High Definition Television The Creation Development and Implementation of HDTV Technology McFarland ISBN 9780786487974 via Google Books Cianci Philip J 10 January 2014 High Definition Television The Creation Development and Implementation of HDTV Technology ISBN 9780786487974 Official Gazette of the United States Patent and Trademark Office Patents U S Department of Commerce Patent and Trademark Office 1977 Csorba Illes P 1985 Image tubes H W Sams ISBN 9780672220234 NEWVICON Trademark Registration Number 1079721 Serial Number 73005338 TRINICON Trademark Registration Number 0940875 Serial Number 72384234 Sony DXC 1600 LabGuysWorld com Color Television Achieves Realism New York Times September 5 1940 p 18 A color 16 mm film was shown live pick ups were first demonstrated to the press in 1941 Columbia Broadcasting Exhibits Color Television Wall Street Journal January 10 1941 p 4 CBS Makes Live Pick up in Color Television Archived October 14 2007 at the Wayback Machine Radio amp Television April 1941 Washington Chosen for First Color Showing From Ages 4 to 90 Audience Amazed The Washington Post January 13 1950 p B2 Gonzalez Camarena Guillermo filed in Mexico August 19 1940 filed in USA 1941 patented 1942 Chromoscopic adapter for television equipment Patent No US 2 296 019 United States Patent Office Retrieved 2017 04 22 Check date values in date help Newcomb Horace 2004 Encyclopedia of Television second edition 1 A C Fitzroy Dearborn p 1484 ISBN 1 57958 411 X Historia de la television en Mexico Boletin de la Sociedad Mexicana de Geografia y Estadistica Sociedad Mexicana de Geografia y Estadistica 97 99 287 1964 Campbell Swinton A A 1896 06 18 The Effects of a Strong Magnetic Field upon Electric Discharges in Vacuo Proceedings of the Royal Society of London 60 359 367 179 182 doi 10 1098 rspl 1896 0032 JSTOR 115833 Hans Busch 1926 10 18 Berechnung der Bahn von Kathodenstrahlen im axialsymmetrischen elektromagnetischen Felde Calculation of the paths of cathode rays in axial symmetric electromagnetic fields Annalen der Physik 386 25 974 993 Bibcode 1926AnP 386 974B doi 10 1002 andp 19263862507 Archived from the original on 2013 01 05 Staff 7 October 2002 Making some sense out of sensor sizes Digital Photography Review Digital Photography Review Retrieved 29 June 2012 a b Nihon Hōsō Kyōkai Hōsō Gijutsu Kenkyujo 1993 High Definition Television Hi Vision Technology Boston MA Springer US pp 55 60 ISBN 978 1 4684 6538 9 OCLC 852789572 External links EditOrthicon Brief history description and diagram The Cathode Ray Tube site CCD Technology A Brief History The German TV museum with a lot of knowledge in German Most of the TV tubes were shown and carefully explained in German Retrieved from https en wikipedia org w index php title Video camera tube amp oldid 1052592697 Vidicon, wikipedia, wiki, book,

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