Talk:Image dissector

Where Farnsworth was born

he was born in utah. Arc88 19:10, 10 April 2007 (UTC)[reply]

But he was a teenage farmboy from Idaho. That is, Idaho is where he was a teenage farm boy. Is there a better way to say it? Putting his place of birth here is at least as misleading as the original. Dicklyon 19:58, 10 April 2007 (UTC)[reply]

How it worked

discussion copied to here from User talk:Dicklyon#Image Dissector for continuation, by User:Dicklyon:

You recently reverted my edit of the description of the Farnsworth Image Dissector saying that it sounded like the operation of Zworykin's design; it does, because they are fairly similar. Please consult the patent application referenced at the bottom of the page which clearly states that the primary method of scansion is detection of the surplus electrons deflected back to the electron gun. Gordon —Preceding unsigned comment added by 130.159.248.36 (talk) 13:11, 15 December 2008 (UTC)[reply]

But you didn't cite a source. It would be best to cite a secondary source that explains it, rather than give your own interpretation of the patent. Dicklyon (talk) 16:00, 15 December 2008 (UTC)[reply]

I agree, sources should be cited. I wasn't however trying to improve the article, I was trying to correct factual inaccuracies I had noticed in my research. I would write a better article if I had the time. "Interpretation" aside, the account I gave was a summary of the description contained in the patent, the current revision as reverted by you is wrong. I fail to see why citing a secondary source as you suggest would be beneficial; I would then be giving my interpretation of someone else's interpretation of the patent. I agree that my revision is not necessarily any better in terms of an acceptable article for Wikipedia, but it was at least true. Arbitrary reversion by you to a false description is bewildering. Gordon 78.105.184.134 (talk) 21:37, 15 December 2008 (UTC)[reply]

Don't be bewildered. See WP:BRD; you were bold, I reverted because I doubted the correctness based on the lack of sourcing, now we're discussing it. My revert was to get your attention to the problem of making your change verifiable, so that if it is it will stick. Now that you say it's pretty much straight from the patent, it should be easy to simply cite that. But also see Wikipedia:RS#Primary.2C_secondary.2C_and_tertiary_sources about why secondary sources are preferred. Dicklyon (talk) 23:03, 15 December 2008 (UTC)[reply]

So I've been looking in Farnsworth's patent filed in 1927, and can't find where you got this stuff. The one you were looking at was the 1933 filing, by which time he had incorporated a storage feature like Zworykin's apparently. So it is my impression that your description does not apply to the original image dissector. If we had a secondary source to help put all this into perspective, that could be very useful. Dicklyon (talk) 01:41, 16 December 2008 (UTC)[reply]

Hey there. As to the Image Dissector. I've done a lot of editing on it recently. It was being described badly, based upon the 1933 patent for a "second generation" dissector that really wasn't a dissector at all, but a storage camera (like the iconoscope) with a new feature--low velocity electrons. Nobody else, not even Zworykin, had come up with that yet. I reworked the major descriptions, added links to the original patents, and pointed out the features of this newer dissector. Playerpage (talk) 14:48, 19 November 2009 (UTC)[reply]

And what you have wrote down is wrong. You firstly wrote that the second generation image dissectors included an "electron multiplier", and then you also stated that this second generation uses a low velocity electron scanning beam. So which is the real version?, is it the "electron multiplier" version or the low velocity electron scanning beam one?

On the other hand, Farnsworth's US patent 2,087,683 is a very representative case. It is very difficult to control a low velocity electron scanning beam, because the electrons in the beam tend to "spread" when the image's borders and corners are scanned, so that one gets an image that is very well focused in the center but blurry in the borders. Iams and Rose were the first ones in solving this problem by using special scanning plates and coils. So that Farnsworth filed a patent for the low velocity electron scanning beam in 1933, but Rose designed and build the first working version of a tube that uses a low velocity electron scanning beam in 1941-1942. And this is not the first time that this situation appears: Dieckmann a Hell filed a patent for the image dissector in 1925, but Farnsworth designed and build the first image dissector in 1927-1928. --189.216.104.69 (talk) 21:24, 16 January 2010 (UTC)[reply]

Two Historical Notes

One of the first all-electronic video camera tubes was invented in France by Edvard-Gustav Schoultz in 1921. He filed the French patent FR-539-613 on August 23, 1921. The patent was accepted on April 5, 1922, and published on June 28, 1922. You can find a copy of the original document in the web page [[1]]

The Image Dissector was also invented in Germany by Max Diekmann and Rudolf Hell in 1925. They filed the German patent DE-450-187 on April 5, 1925. The patent was accepted on September 15, 1927, and published on October 3, 1927. You can find a copy of the original document in the web page [[2]]

--134.153.204.160 (talk) 15:50, 24 July 2009 (UTC)[reply]

And nether bore more than a passing resemblance (if that) to Farnsworth's design, which actually produced an image. (Imagine that! A device that not only bore a patent, but did what it claimed to do.) Wasn't it Hell himself who said they couldn't get the thing to work because the didn't understand how to focus electron beams ("electron optics")? Cheers, Rico402 (talk) 06:57, 31 July 2009 (UTC)[reply]

Indeed, there's a lot to be said for getting one's invention to work. In wikipedia, it's a losing game to engage in invention priority disputes based on primary sources like patents. I think we just shouldn't allow that. It's OK to report the existence of these early patents, but statements about exactly what was invented, or who should get credit for what, definitely need to be backed up by secondary sources. Even then, there will be disagreements, in which case we should simply report who takes what sides, and avoid taking sides ourselves. Dicklyon (talk) 07:05, 31 July 2009 (UTC)[reply]

So would you support routine reverts (judiciously applied) when someone inserts a specious claim into an article based solely on a patent, without first doing a song and dance on the Talk page? (Cause I've been seeing, and doing, a lot of that. :) Cheers, Rico402 (talk) 07:35, 31 July 2009 (UTC)[reply]

Personally, I'm big on the "R" step in WP:BRD; the "D" can follow if the reverted editor wants to make a case. Especially on issues of priority and invention, we have no business making claims based on primary sources. One can say "X filed a patent application on similar device in Y year", but not "X gets credit for inventing...". But even there, if "similar device" is subject to dispute, and not verifiable in secondary sources, that should be taken out. Dicklyon (talk) 16:36, 31 July 2009 (UTC)[reply]

I think it should be noted, as well, that we at Wikipedia do not represent the sum total of all Wisdom. We may be trying to pool all knowledge, but that is a different thing. An example can be found in the Farnsworth debate. During the heady days of invention, he grabbed as many headlines as his colleagues. After the world settled into the drive to buy TV's, he was lost in the corporate siren of RCA's marketing dept. It is only in the last 25 years that he has emerged from the shadows to be taken more seriously for the contributions he made. A single thought, from a single individual, should never be the end-all of the debate. That was what happened to Farnsworth. Careful documentation, many verifiable sources, and what is the community at large--both inside and outside Wikipedia, inside and outside whatever discipline is being covered even--saying on the subject? Playerpage (talk) 15:00, 19 November 2009 (UTC)[reply]

And you should rename this web page as: Farnsworth's work, the image dissector and other inventions that never worked. --189.216.74.201 (talk) 03:36, 2 February 2010 (UTC)[reply]

Topic of this article

The topic is Farnsworth's image dissector, not the history of television. It would be OK to have a brief section on other inventions around the same time, but to hijack the lead to give credit for his invention to others seems inappropriate here. Agree? Dicklyon (talk) 02:58, 31 July 2009 (UTC)[reply]

I asked admin VirtualSteve to protect the article -- protection template in place til 7 Aug. Cheers, Rico402 (talk) 05:46, 31 July 2009 (UTC)[reply]

Seems like overkill at this point, but still, the anons can make their case here on the talk page if they wish. Dicklyon (talk) 06:20, 31 July 2009 (UTC)[reply]

I wouldn't call it overkill -- every article re television has been under attack; one can hardly keep up. The same specious crap has been popping up like weeds all over the place. All the time wasted on reverts could have been spent actually improving the articles.

And 134.153.204.160 posted his "Two Historical Notes" on nearly every Talk page having anything to do with television. The list of "twelve patents for an all-electronic video camera tube filed or issued before Farnsworth's" was posted nearly everywhere as well. But I don't think these guys mucked up the actual articles. Cheers, Rico402 (talk) 07:22, 31 July 2009 (UTC)[reply]

Someone has to clean this article

Someone has to clean the redaction of this article because it is horrible. It is firstly said that: second generation dissectors equipped with Electron Multipliers, as they came to be known, were in demand by RCA for their unique technology. RCA leased the technology from Farnsworth in 1939 and incorporated it into their future television systems.

As far as I know, the electron multiplier was invented by Joseph Slepian in April 1919 [[3]]; and the multi-stage electron multiplier was developed by Kubetsky in 1933 [[4]]. Thus could anyone please explain me why RCA would lease the electron multiplier technology from Farnsworth, instead of leasing it from Slepian? I wonder the author is not trying to say that Farnsworth also invented the electron multiplier.

It is later said that: Farnsworth submitted a patent application for a second-generation Image Dissector in 1933, based on what he learned working with his original designs and the multipactor. The new Image Dissector — actually a cathode-ray tube (CRT), and the first to use a low velocity electron scanning beam — would become the ancestor of the Image Orthicon tube, ...

What? Farnsworth invented the low velocity electron scanning beam in April 1933 [[5]], introduced (but did not invent) the one-stage electron multiplier in January 1928 [[6]] [[7]], invented the multicaptor multiplier in October 1933 [[8]], and used a two-stage electron multiplier (2 dynodes) in April 1937 [[9]]. A multi-stage electron multiplier (5 dynodes) was then introduced in August 1937 [[10]]. Thus what makes a second generation image dissector?, is it the electron multiplier or the low velocity electron scanning beam?, please make your mind.

Even the ITT image dissectors with modern electron multipliers (12 dynodes) were not as sensible so as to be used in outside broadcasting, they were reserved for industrial applications [[11]], [[12]], and [[13]]. The real solution for the inefficiency problem was not the electron multiplier, but the charge storage principle. By the way, Farnsworth's US patent 2,087,683 was based in Tihanyi's work from 1928 [[14]], [[15]], and [[16]]. Yes indeed, Farnsworth did have access to Tihanyi's british patents published in 1930. Finally the first practical and all-functional iconoscope was build in November 1931 and presented to the general public in June 1933, the year 1934 is just wrong.

--148.247.186.142 (talk) 01:27, 15 January 2010 (UTC)[reply]

I believe these concerns have been adequately addressed, but I can't guaranty they won't crop up again. I'm reasonably certain I removed the whole "second generation image dissector" bit a while ago, but it recently resurfaced.

The confusion over Farnsworth's 1930 "electron multiplier" and contemporary dynode electron multiplier has also been addressed. I believe this confusion is why another editor referred to Farnsworth's "electron multiplier" as a "multipactor", a term he apparently didn't employ until his 1935 patent application Multipactor Phase Control, Patent No. 2,071,517. As I'm sure you know, the devices are quite dissimilar. Cheers, Rico402 (talk) 23:57, 12 March 2010 (UTC)[reply]

This article is an example of hypocrisy

Dieckman and Hell's German patent number 450,187 is dismissed as an ancestor of the image dissector because they never constructed a fully functional device. However, Farnsworth's US patent number 2,087,683 filed in 1933 is presented as the ancestor of the image orthicon even when he never built a fully functional device.

The devises using a low velocity electron scanning beam are so sensible that they can be used for outside broadcasting [[17]]. If Farnsworth ever built a fully functional model of his US patent 2,087,683 before 1938, why did he never announce that he was doing outside broadcasting, while Zworykin could not do so? The first outside broadcasting was done by the British in November 1937, before that Zworykin could do the same in the USA.

The devises using a low velocity electron scanning beam produce images which are well focused in the center but blurry in the borders [[18]]. If Farnsworth ever built a fully functional model of his US patent 2,087,683 filed in 1933, why did he never patent a solution to this focusing problem? One only needs to search at google-patents [[19]] in order to discover that Farnsworth only produced three related patents: US 2087683, US 2237334, and US 2107778, none of the them solving the focusing problem.

The orthicon and image orthicon were once upon a time the American industrial standard for broadcasting. If Farnsworth ever built a fully functional model of his US patent 2,087,683 before 1935, why did he abandon this device and worked instead on the "electron multiplier" (multicaptor) image dissector that can only be used in industrial applications [[20]])? Search at google-patents [[21]] in order to discover that Farnsworth produced five patents for an image dissector with a miniature multicaptor in 1935: US 2221473, US 2143262, US 2149045, US 2153918, and US 2235477; and two patent for an image dissector with a multistage "electron multiplier in 1937: US 2161620 and US 2200166 (signed by Gardner).

In conclusion, Farnsworth never built a fully functional model of his US patent 2,087,683 and this article is an example of hypocrisy. Dieckman and Hell's German patent number 450,187 is dismissed as an ancestor of the image dissector because they never constructed a fully functional device. Nevertheless, Farnsworth's US patent 2,087,683 is presented as the ancestor of the image orthicon even when he never built a fully functional device. --148.247.186.142 (talk) 21:52, 18 January 2010 (UTC)[reply]

Yes, you are completely right. Just imagine the work done by the British team. Lubszynski and Rodda invented the super-emitron for EMI on May 12, 1934 [[22]], and 83 days later Blumlein and McGee also invented the cps-emitron (a low velocity electron scanning beam tube) for EMI on August 3, 1934 [[23]] [[24]]. They only needed three years for constructing a fully functional camera and to directly broadcasting the King laying a wreath at the Cenotaph in November 1937, a broadcasting from an exterior location [[25]].

On the other hand, Farnsworth invented the low velocity electron scanning beam in April 1933 (US patent number 2,087,683), but he was never able to directly broadcast anything from an exterior location, anything outside a well illuminated television studio. Farnsworth had to film the scenes from an exterior location and to project the film onto an image dissector in order to broadcast them.

--189.216.128.152 (talk) 03:22, 20 January 2010 (UTC)[reply]

Moreover, orthicon and cps-emitron low-velocity scanning tubes have an instability problem. Whenever sudden flashes of bright light entered the scene, they produced the appearance of a large drop of water slowly evaporating over part of the scene [[26]][[27]]. Farnsworth never mentioned this kind of instability in his notes, because he never constructed any functional version of the device described in his US patent 2,087,683. It is also obvious that the authors of this wikipedia-article are sexing up Farnsworth's work, they only need to say that Farnsworth also discovered the penicillin and constructed the Saturn V American rocket, but the Scottish Alexander Fleming and the evil German Wernher von Braun took out the ideas and honor away from him.

--189.217.113.51 (talk) 02:26, 10 February 2010 (UTC)[reply]

I would rather say that one does not know whether the authors are driven by ignorance or bad intentions. For example, they say that the multipactors came to be known as electron multipliers. That is wrong, for the multipactor is a special type of the electron multiplier invented by Slepian in 1919 [[28]]. The multipactor has two anodes connected to an alternating voltage so that the electrons keep bouncing back and forth between the anodes, and several secondary electrons are produced every time the electrons strike each one of the anodes [[29]]. The authors also say that the U.S. patent number 1,969,399 [[30]] is a multipactor, and that is wrong, the device is a multi-stage electron multiplier. The first U.S. patent for a multicaptor is the 2,071,515 [[31]].

The authors say as well that the U.S. patent number 1,773,980 [[32]] (filed 1927, issued August 1930) is the first one issued in the U.S. for a television system. This is also wrong, Farnsworth was the first person on earth in giving a public demonstration of a fully-working electronic television camera, but he neither filed nor was honored with the first patent for an electronic television camera in the U.S. There are several other patents before, just look at the patent numbers that are assigned according to the issuing date: U.S. 1,691,324 [[33]] (filed 1925, issued 1928), U.S. 1,694,982 [[34]] (filed 1925, issued 1928), U.S. 1,706,185 [[35]] (filed 1925, issued 1929), U.S. 1,745,029 [[36]] (filed 1927, issued January 1930).

The authors finally say that the U.S. patent 2,087,683 (filed 1933, issued 1937) is a precursor of the iconoscope built by Essig in 1931 [[37]] [[38]]. Do I need to say something else?, It is obvious that the authors try to sex up Farnsworth's work, but they are doing such a sloppy (and laughable) research that one cannot be mad at them. One must preserve this wikipedia-article as an example of obviously biased work.

--148.247.186.142 (talk) 18:32, 10 February 2010 (UTC)[reply]

Every time that I read this wikipedia-article, I find a lie. The author says that there is a bibliographic reference for Farnsworth's multipactor in page 148 of (1987) Albert Abramson's book: The History of Television, 1880 to 1941. Nevertheless, I just look for the word "multipactor" in the copy of Abramson book located in google-books, and I found nothing; please read the link [[39]]. On the other hand, I also look for the words "electron multiplier" in the same copy of Abramson book and I found three references in pages 148, 244, and 245; please read the link [[40]]. How is possible that someone who cannot distinguish between a multipactor and an electron multiplier dares to write down anything in a wikipedia-article?

--189.217.95.212 (talk) 03:52, 21 February 2010 (UTC)[reply]

Your commentaries have been taken in consideration. --148.204.17.158 (talk) 03:08, 12 March 2010 (UTC)[reply]

I would request that others please not write "the authors" say this, "the authors" say that. As best I can tell, most of the baloney in this article has been sliced up and tossed around by a single editor, who had also corrupted the Video camera tube article. I've given him/her a bit of a rebuke here: "Recent edits erroneous, poorly sourced or POV". I have devoted a considerable amount of time researching, editing and maintaining the integrity of this article, as have had others, but I can't be expected to be continuously protecting it against destructive edits. The recent errors I suspect were well-meaning, but terribly misguided.

Re Dieckman and Hell's 1925 German patent: This was not an ancestor of Farnsworth's 1927 patent. The two teams worked independently with no knowledge of the others achievements. Moreover, Farnsworth had conceived the design in 1920. No reputable source disputes this. And Farnsworth's 1933 patent is presented as the ancestor of the image orthicon just as Kalman Tihanyi's 1928 patent is presented as the ancestor to the iconoscope. In both cases the essential elements where in their respective patent applications. There exists no known evidence, even anecdotal, to suggest that Tihanyi ever built a camera or display tube based on the designs he submitted in 1928. As for Farnsworth's 1933 CRT camera tube, he could not market a tube based on this design because RCA held the patent rights for much of the technology, with the notable exception of "low-velocity scanning", although his design included other unique features. With his limited resources, he likely couldn't spare the money and manpower to construct a device he (or Philco, for whom I believe he was working at the time) couldn't sell. Had he built the device, it seems likely he would have discovered and resolved the "blurry image" problem.

Farnsworth did indeed design dissector tubes that worked adequately in direct sunlight, when equipped with his "electron multipliers". Such tubes were used in his 1934 demonstrations in Philadelphia.[Abramson, Albert (1987), The History of Television, 1880 to 1941. McFarland & Co., Inc., p. 209-210. ISBN 9780899502847.] They worked indoors as well, although the heat from the required lighting reportedly created some problems.

Indeed you will not find "multipactor" on page 148 of Abramson's The History of Television, 1880 to 1941. This is the name Farnsworth gives his "electron multipliers" (not to be confused with dynode electron multipliers) beginning with Patent No. 2,071,517, Multipactor Phase Control in 1935. The reference cited for Farnsworth's "multipactor" would better be described as an "error", rather than a "lie". (In either case, it's not mine.) The citation refers to "electron multiplier", which is indeed found on p. 148 of Abramson: "The final electron flow was a function of the potential ... and the number of impacts." (The device amplifies an electrical signal by harvesting a very large number of secondary electrons emitted as a result of multiple electron impacts; hence the term "multipactor".)

Finally, I would politely suggest contributors familiarize themselves with the meaning of such incendiary words as "hypocrisy before they use them to attack others, if even indirectly by attacking the article. Indeed I believe it best to refrain entirely from such pejorative and inflammatory language,

Let us please not cast insults nor hold hard feelings toward one another. Cheers, Rico402 (talk) 23:26, 12 March 2010 (UTC)[reply]

PS: Cheers to anon 148.247.186.142 for clarifying the description of "multipactor". (But you're still not quite off the hook for the "hypocrisy" remark. ;-) Rico402 (talk) 00:06, 13 March 2010 (UTC)[reply]

Let me see. Do you really want us to believe that outside broadcasting means filming at close range in a really sunny street [[41]]? Maybe you would want to take a close look at the pictures presented in the book [[42]], you can see there how the BBC installed television cameras in the roofs of several buildings in order to film the King laying a wreath at the Cenotaph in November 1937. I assume you know that the teleo-objective diminishes the amount of light available to the video camera tube; and I prefer avoid talking about the Olympic Games of 1936 because I have not found yet a documented picture of a real Superikonoskop camera filming the games.

Moreover, do you have any hard proof that Albert Rose and H. Iams inspired themselves in Farnsworth U.S. patent number 2,087,683 [[43]] in order to design and build their orthicon? Can you prove that Rose and Iams did not inspire themselves in the work rather done by Blumlein, McGee and Lubszynski between 1934 and 1936 [[44]] [[45]] [[46]], considering the fact that EMI and RCA were friend companies by then? It is obvious that RCA had to buy Farnsworth patent (for one million?) in order to be able to sell the image orthicons, but that does not mean that Rose and Iams inspired themselves in Farnsworth patent. Notice that I am not saying that the c.p.s. emitron is the ancestor of the image orthicon, for Blumlein, McGee and Lubszynski can shine by their own achievements, they do not need us to place fake wreaths in their graves.

It is quite offensive to hear how fans complain about RCA dismissing Farnsworth work, when at the same time they dismiss the work done by everyone else. For example, considering just one cometary done by Playerplage, Farnsworth introduced the magnetic focusing into his image dissector in 1928 [[47]], does that make him the father of the magnetic focusing in general? Obviously not, because Swinton discovered in 1896 that the magnetic field generated by an axial coil can focus an electron beam [[48]], Fleming corroborated this discovery in 1897 [[49]], Dauvillier used the magnetic focusing in a (CRT) picture tube in 1924 [[50]], and Busch gave a complete theoretical explanation in 1926 of how the magnetic focusing phenomenon works in [[51]]. Indeed, Farnsworth was the first one to introduce the magnetic focusing into his image dissectors (thing that neither Dieckmann nor Hell did), but that does not make him his father.

Just to conclude, someone should write down about the fact that the image orthicon was a financial failure for RCA. They had to keep the television laboratories working for approximately 20 years, they had to buy Farnsworth patents for one million, and at the end they have to compete against the European image iconoscope (which was cheaper, I suppose). And, Rico402, are you really talking seriously when you say that I am still not quite off the hook?, are you really trying to advice me?, do you really want me to get good notes and to justify myself so that I can be off the hook? You are seriously kidding. Actually, maybe you would want to be so kind so as to explain us which is the right adjective we ought to use for describing those fans who complain about RCA dismissing Farnsworth work, when at the same time they dismiss the work done by everyone else.

--148.247.186.142 (talk) 20:03, 15 March 2010 (UTC)[reply]

The "off the hook" remark was offered in jest, which should have been obvious, as it closed with a "wink" emoticon. And I would advise you to tone down rhetoric. There's nothing to be gained by constantly insulting your fellow editors. And if you must persist in being so abrasive and condescending, then yes, I do "really want [you] to get good notes and to justify [yourself] so that [you] can be off the hook?" Rico402 (talk) 06:29, 16 March 2010 (UTC)[reply]

Contemporary image dissectors

Image dissectors are still being used in specialized applications, particularly for astronomical observations. I've found a few NASA papers and research articles, but nothing more general so far. If anyone has something to contribute on this, please feel free to add your remarks below. Cheers, Rico402 (talk) 00:19, 13 March 2010 (UTC)[reply]

Yes ideed, the image dissectors were used in astronomy and spectrometry well into the 1980, but not the common industrial type [[52]] [[53]] [[54]] [[55]] [[56]]. By the way, I am not devoted to undermine Farnswoth's accomplishments, I am rather devoted to stop the advances of those who think that television was only developed by Farnsworth and RCA, and so they will happily dismiss the work done by everybody else. Believe or not, by my own experience, Farnsworth fans are those who are more prone to dismiss the work done by anyone but Farnsworth himself.--189.217.5.125 (talk) 02:15, 16 March 2010 (UTC)[reply]

You would also be interested to know that Farnsworth multipactors also have recent applications. They are used as electron guns, for they can produce intense narrow pulses (bunches) of electrons [[57]] [[58]] [[59]] [[60]] [[61]] [[62]] [[63]]. You see, Rico402 and Playerpage, it is perfectly possible to find a lot of places where Farnsworth work has had quite important implications, and so you do not have to dismiss the work done by other people.--189.216.100.98 (talk) 07:13, 16 March 2010 (UTC)[reply]

Actually I was talking with one of the old professor in the department of Astronomy, and in his own words: his generation completely felt in love with the image dissector (ils sont absolument tombé follement amoureux du dissector d'image). They had to count the spectrum lines by hand (or by eye) before the image dissector arrived, and they loved it because its response was essentially linear over a broad illumination-range, unlike other video cameras. Here are some references: [[64]] [[65]] [[66]] [[67]] [[68]]. I obviously asked him how did they deal with the sensibility problem, for the star light is not very strong at all, and here is the answer: There was a three stage image intensifier placed in front of the image dissector, so that the incoming image was amplified before being transform into an electronic image, and the scanned electric image was then amplified with a 12-dynode electron multiplier. He called this device a intensified image dissector [[69]].

He also told to me about another pair of video tubes. One was the image isocon. It seems to be that the returning beam in an image orthicon has two components, some electrons are reflected by the glass target, while other are scattered by it, so that the scattered electrons are separated, amplified, and used as the video signal [[70]]. The resulting image isocon was approximately between five to ten times more sensible than the image orthicon, but it was never a real commercial success, because it was more complicated and fragile than the already complicated image orthicon. The other tube is much more interesting and robust. The scene image is transformed into an electronic image by a semitransparent photo-cathode, the resulting electronic image is then accelerated and focused into a target composed by a myriad of silicon diodes. The accelerated electrons increase the conductivity of the diode target when they land on it (due to the avalanche effect), so that this target can be scanned as in the plumbicon case. The resulting video camera tube is more sensible, simple, and cheaper than the image orticon, but less sensible than the image isocon. It had a very good welcome in the physics community. I feel writting about it in the future, well if I can find which was its real name. --148.247.186.142 (talk) 18:27, 16 March 2010 (UTC)[reply]

Oh, I forgot to say that the physics community also loved the (intensified) image dissector because you can access any pixel at any time (at random) [[71]] [[72]] [[73]], while you have to wait until the rasterisation is completed in the charge storage cameras in order to access a given pixel, for otherwise the charge storage process cannot be done properly.--148.247.186.142 (talk) 20:08, 16 March 2010 (UTC)[reply]

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Nandoss

mapotu

Bem

Manwayela

41.121.102.165 (talk) 17:47, 18 October 2023 (UTC)[reply]

History

This incomplete sentence should be edited for spelling and grammar.

Though RCA had paid royalties though in 1939, legal cost associated with RCA's patent disput, war time manufactuing pressure, Farnsworths patnet expiring just eight years later, and his understandable disilutionment his company would be dissolved shortly after world war two. Khoitsma (talk) 18:16, 20 February 2024 (UTC)[reply]