Talk:Video camera tube

Orthicon & tube sizes

One item that has not been discussed is the relative size of the various camera tubes. This is not much of an issue for studio cameras, but can be of considerable concern for portable cameras.

Typical Image Orthicons are rather long (approximately 18 inches), while Vidicons are typically only a few inches long. Additionally, Image Orthicons are typically many inches in diameter (3-4.5 inches), while Vidicons may be less than an inch in diameter. The result is that cameras using Image Orthicons are typically rather huge boxes, while cameras using Vidicons may be held in the palm of a hand.

Another issue that has not been addressed is the ruggedness of the various tubes. Image Orthicons can be quite fragile. The target plate in an Image Orthicon is made from glass and is quite thin, which results in it being rather fragile. The target must be of an insulating material, and thin enough that electric charges deposited on the front of the tube by the photoemitted electrons can migrate through the thin layer to the back of the target, where they will be scanned by the electron beam. One of the cautionary notes about the operation of Image Orthicon tubes states that they should never be pointed with the face below about a 30 degree angle. This is to prevent any debris, which may be present at the back of the tube as a result of the manufacturing process, from sliding forward along the neck of the tube and impacting the target, since such an impact, even by a tiny bit of debris, is likely to shatter the target.

Another cautionary note involves the operating temperature of Image Orthicons. The photoemissive layer at the front of the tube is somewhat volatile. Thus, the tube should never be subjected to operation in temperatures at which the photoemissive material could evaporate, since it would likely be deposited on the target, which would ruin the charge storage mechanism that the target operates on. A similar effect can be produced by excessive illumination. Thus, an Image Orthicon should never be aimed, even momentarily, such that its view images the sun or a bright light, since the energy focused on the photoemissive surface may be intense enough to cause evaporation of the photoemissive material.

A counter-effect is that the characteristics of the photoemissive material are somewhat temperature sensitive, which means that Image Orthicons may lose some sensitivity in cold temperatures. Thus, some camera equipment which used Image Orthicons would provide a heater to warm the front of the tube in cold weather.

---

Dave

Iconoscope's sensitivity

• The iconoscope section needs some work. Larger "lux" values indicate less sensitivity. "75,000 lux" is a terrible sensitivity. Tropical noon sunlight is around 100,000 lux.

That number can't be right. It's all over the web, but it has to be wrong. The source of this misinformation seems to be http://www.akh.se/tubes/camera.htm . Iconoscopes were insensitive, but not that insensitive, at least in their later forms.

• It should be mentioned that the image orthicon combines the advantages of the image dissector and the iconoscope. The orthicon was the first tube that had decent sensitivity.

--Nagle 18:50, 11 March 2006 (UTC)

• In re this question, it seems possible that what is meant is that a light source of about 75klx intensity is required for a decent image. Having taken photographs of stage-lit events I can confirm that the light intensity is usually comparable with cloudy daylight, and stronger lighting is certainly possible. It does seem unlikely that what is meant is that the tube could only register--as a minimum--signals of 75klx.

• It is also possible that the article refers to the first tubes only.

• The datasheet for the RCA 5820 Image Orthicon, states "Commercially acceptable pictures can be obtained at incident light levels greater than about 10 foot-candles". So unless I am wrong, that means: 10fc = 107.64 lux is pretty near the 200lx as described generally in [1]. While the RCA 1848 iconoscope says "Good operation can be obtained with a highlight illumination level on the mosaic in the order of 7 foot-candles", so roughly 75lx, NOT 75Klx (perhaps there was a typo or a conversion error). However, this appreciations are subjective, because that would mean that the iconoscope was more sensitive than the IO, which is completely impossible. My best guess is that simply what was considered good in 1940 was not in 1950s. According to Terman in Radio Engineering, IO should be between 100 and 1000 times more sensitive than the iconoscope. Alchaemist (talk) 04:34, 13 March 2009 (UTC)

Alchaemist -- do not confuse SCENE illumination, the light falling on the subject and TARGET illumination, the light collected by the lenses and delivered to the tube's target.

I am looking at the original paper data sheet from the published and readily available RCA HB-3 Handbook, for the 5820 Image Orthicon dated Sept 15 1949, Its states "...illumination on photocathode for maximum signal Output: 0.01 ft-c" You can find a sheet from Philips for their 5820 at http://tubedata.milbert.com/sheets/030/5/5820.pdf stating similar values.

The data sheet, same source, for the RCA 1850-A Iconoscope states that the required illumination on the target should be between 4 and 20 ft-c.

The Iconoscope is about a thousand times less sensitive than an Image Orthicon. To convert foot-candle to lux multiply by 10.8 OldZeb (talk) 05:39, 15 March 2009 (UTC)

Excellent! Thanks for noticing it, what I looked didn't specify so. The PDF I have for 1848 iconoscope, didn't have any values, neither a curve. I'll correct these values in the article with the ones you mention. Regards! Alchaemist (talk) 03:35, 16 March 2009 (UTC)

Orthicon or Image Orthicon

My recollections of camera tube types are that there is a difference between the "Orthicon" and the "Image Orthicon" tubes. The Image Orthicon was developed out of the Orthicon tube which was invented by Arthur Rose in 1937/38. The Orthicon had no what we used to call "Image Amplifier" located in the larger section at the front of the Image Orthicon tube. So, for the article to be correct, the heading “Orthicon” should really be changed to “Image Orthicon”, the words "or simply orthicon tube" removed and another heading and description for its ancestor the “Orthicon”. I’m having a problem locating technical information about the Orthicon (sans Image) tube but I found a diagram and a bit more information at: http://members.chello.nl/~h.dijkstra19/page4.html and an IEEE reference at: http://www.ieee.org/organizations/history_center/legacies/rose.html. In Australia we were using Image Orthicon cameras at least into the 1970's. Fernseh brought out the only solid state Image orthicon camera I know of in about 1968. We referred to the tubes as "IO's". Peter Resch 06:39, 28 April 2006 (UTC)

Elaboration on above comment and 'emmy' correction

The nickname 'emmy' came from another tube from the same family, the Emitron (or CPS Emitron). (for more, see http://www.burle.com/cgi-bin/byteserver.pl/pdf/pctdhbook.pdf which is based from original source material, see its footnotes) The Image Orthicon, or IO, and the emitron, or CPS Emitron, both used a mosaic type photoemitter.

Regarding the comment above, I believe he's talking about the earlier Multiplier Orthicon. The MO tube had an electron multiplier in it that amplified the signal prior to sending it to the video amp so as to produce a stronger but still relatively clean input signal. But the IO tube also had a multiplier built in for the same purpose, but also had a two-sided target. And both were sent to a video amplifier. The multipliers were to boost the weak source signal. On principle I agree with the notion of making the heading just 'Orthicon', but generally when people talk about orthicon tubes, they're talking about IO tubes as they were the more advanced and in more widespread use.

140.247.121.204 (talk) 15:18, 20 March 2008 (UTC)

A not so tiny detail

I'd like to see this article explain how it's possible to have a beam going from electron gun to target and then have a return beam. If high voltage is what accelerates the beam one way then I'm confused how a beam can then go the other way. That's the sort of thing that's glossed over and I'd be very curious about. Steve / filmteknik

Steve,

The electrons will land on the target only as long as the target potential is higher than the cathode potential. All remaining electrons are either reflected or scattered depending on their arrival energy and return towards the cathode. Most will be captured, however, by the aperture electrode, which is beloe cathode potential. It is at this point that electron multiplier structures can be inserted to read out the return beam as is done in image orthicons (read the reflected beam) and isocons (read the scattered beam.

Dave Gilblom

Vladimir Zworykin vs Philo Farnsworth

This article gives primary credit to Vladimir Zworykin and minimizes the contribution of Philo Farnsworth in the invention of the television camera. Farnsworth is responsible for the key idea of using a 2 dimensional matrix of photosensitive material to create the electronic signal. Zworykin, backed with the resources of RCA, improved on Farnsworth's ideas and created the iconoscope. Although Zworykin/RCA attempted to claim the entire invention, the US patent office found in favor of Farnsworth and RCA was required to pay royalties to Farnsworth for his patents. Farnsworth version of the story can be found here http://www.farnovision.com/chronicles/tfc-who_invented_what.html http://www.farnovision.com/chronicles/tfc-intro.html Zworykin/RCA version of the story can be found here http://www.acmi.net.au/AIC/ZWORYKIN_BIO.html

Kharkless

I am sorry to say this but the idea of using a 2 dimensional matrix of photosensitive material goes back to Alan Archibald Campbell Swinton who presented this idea in the paper Distant Electric Vision printed in the journal Nature 78, 151 (18 June 1908), several years before Farnsworth. You can find a copy of this paper in the web page:

http://www.nature.com/nature/journal/v78/n2016/pdf/078151a0.pdf.

Even in Farnsworth's wikipedia file it is textually said: [In 1930, after a visit to Farnsworth's laboratory, Vladimir Zworykin copied this apparatus for RCA, though he found it impractical and returned to his work on the iconoscope. The U.S. Patent Office rendered a decision in 1935 that the "electrical image" of Farnsworth's image dissector was not in Zworykin's inventions, and priority of that invention was awarded to Farnsworth].

RCA indeed paid in 1939 one million dollars for Farnsworth's patent on the "Electrical Image" concept because they needed the patent rights to produce their Image Orthicons (built by Rose, Law, and Weimer in 1944-1945). The image part (photocatode and target) in the Image-Orthicon is indeed a Farnsworth's Image-Dissector, but Zworykin's Iconoscope does not use any "Electric Image" as the U.S. Patent Office dictaminated. Zworykin used Tihanyi's ideas, but not Farnsworth's ones. —Preceding unsigned comment added by 189.216.171.103 (talk) 05:08, 10 March 2009 (UTC)

Plumbicon Tubes

In the TV series Monty Python's Flying Circus, they used EMI 2001's with Plumbicons. In one episode, Episode 17, a model of a building exploded and caused the camera to show a glowing red and green halo and then it faded away. Was this a malfunction? Curvebill 18:48, 9 September 2007 (UTC) by abhinav —Preceding unsigned comment added by 59.93.70.119 (talk) 16:51, 19 October 2008 (UTC)

Plumbicon based cameras were the mainstay of earlier BBC colour broadcasts (and of most other broadcasters of the time). The effect you describe was a characteristic of the plumbicon tubes. It was obserevable on many other programmes where bright lights or light reflections were included in shot. The colour change came about because the decay of the image on the target of the tube was different in the three tubes with the green having the longest delay. This was because the composition of the targets differed between the tubes to optimise the response to the colour it saw (red, green or blue). 86.134.120.174 (talk) 14:58, 3 February 2010 (UTC)

Image Orthicon copy-edit

• I rewrote the subsection Operation of the Image Orthicon to be more precise and accurate. I based myself in Radio Engineering by Frederick Terman from 1947. I would like to cite it as a source, however it applies to the whole subsection, rather than a part of it, so I don't know where to put it. Finally, I don't think the copy-edit note should stay for the Image Orthicon section, what do you think? Should we remove it? Regards! Alchaemist (talk) 03:57, 13 March 2009 (UTC)

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 [[2]]

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 [[3]]

--134.153.204.160 (talk) 15:47, 24 July 2009 (UTC)

Image Dissector

Starting around 27 July, an anon editor has been rewriting the image dissector section, and the image dissector article, too, to give credit for that device to others besides Farnsworth. I have no problem crediting the others for what they did, but it was my impression that "image dissector" was a specific reference to Farnsworth's device. Is there evidence that the inventions of the others are referred to by the same term? Or shouldn't they have their own section(s)? I introduced an "Early steps" section to separate those from the Farnsworth tube. Dicklyon (talk) 06:39, 31 July 2009 (UTC)

Note that Dieckmann and Hell did indeed call their primitive (and unworkable) electronic imaging device "Image Dissector". The title of their 1925 patent application, "Lichtelektrische Bildzerlegerröhre", literally translates to "Photoelectric Image Dissector Tube".

licht = photo; elektrisch = electric; bild = image; zerlegen = dissect; röhre = tube.

Source: Follett Vest-Pocket Dictionary: German, (German-English / English-German), Follett, 1970.

Cheers, Rico402 (talk) 15:24, 31 July 2009 (UTC)

Right, I had already verified that translation, though my translation sources suggested "break" and "burst" rather than "dissect"; I just wanted to know if "dissector" was sourced in this context, as I always thought that was a uniquely Farnsworth term; turns out it is sourcable for the Dieckmanna/Hell device, too, so I added a bit about that. I think this section still suffers from too much editor interpretation of primary sources, which is really unnecessary, since there is a huge secondary literature, easy to find, on this topic. Dicklyon (talk) 16:32, 31 July 2009 (UTC)

Mr. Anon, thanks for all your info. Why don't you make yourself an account and help us get the article improved? My objections before were based on my inability to verify some of your assertions, and what I thought was improper structuring of the contributions of others inside the section on the image dissector, which I had thought was a specific reference to the Farnsworth device. Now that I know there are sources that apply that term to the Dieckmann and Hell device, I've gone ahead and cited those sources. What's important in getting your contributions to stick in Wikipedia is simply good sourcing, to clearly indicate whose information or interpretation is being summarized. Your own interpretations of primary sources (e.g. patents) will not usually survive in a topic like that one, where there is a deep secondary literature that should be relied on.

I'm also willing to ask for a removal of the semi-protect if you say that you're willing to cooperate but don't want to make an account for some reason. Dicklyon (talk) 04:41, 1 August 2009 (UTC)

Dicklyon, you're being too forgiving. This is the same unregistered user who altered the text to read:

"The first practical all-electronic camera tube was the Image Dissector filed for patent by Dieckmann and Hell in 1925 (patent issued in 1927) and filed again for patent and demostrated (sic) by Philo Farnsworth in 1927 (patent issued in 1930)." (Emphasis added.)

He's arguing that Dieckmann and Hell produced the fist "practical" design, and that Farnsworth just coincidentally duplicated their work. It's an utter falsehood, considering that Dieckmann and Hell's design bears little resemblance to Farnsworth's, they could never get it to work, and they didn't even have an approach to understanding how to make it work. What's the point of being the "first" to patent a gadget if one doesn't know what he's doing and his gadget doesn't work and his research goes nowhere.

This is just another in a long series of attempts to undermine Farnsworth's contributions to the field with specious claims of priority.

Btw, the "semi-protect" stays until 07:41, 6 August 2009 (UTC). Cheers, Rico402 (talk) 09:58, 1 August 2009 (UTC)

I agree that we need to push back on such "attempts to undermine Farnsworth's contributions to the field with specious claims of priority." But it shouldn't require admin intervention like semi-protection to do so (and it's only a temporary help anyway). I think it's better to have a dialog, explain the rules of WP:V, etc., and then if he won't go along with the rules we can ask for a more specific remedy. But like I said, I'm not so familiar with your history with him; maybe you've already tried that? Dicklyon (talk) 21:03, 1 August 2009 (UTC)

Rico and anon, I presume you guys have a history that's making you act this way toward each other; let's try to break out of it. Rico, don't fall for his bait. There's no need to discuss his interpretation of original patents and other primary sources. Let's just focus on the right stuff, namely summarizes what other historians have already concluded and published, then we can avoid having to argue over all that other stuff. Dicklyon (talk) 17:21, 1 August 2009 (UTC)

No, no, no... Anon is just a not-so-innocent bystander. ;)

For my part, it's primarily Celebration1981's many destructive edits (also under various IP's) and inflammatory comments on the Talk pages that has my knickers in a twist, and has lowered my tolerance for un- or poorly-sourced claims and specious arguments. I dealt with that clown for nearly a year on History of television and related articles (and more recently, Transformer) — as you say, "dialog, explain the rules" — wasting huge amounts of valuable time reverting his edits, re-phrasing his plagiarisms, and futilely rebutting his arguments on the Talk pages. I'm just unwilling to waste any more time, and want to move forward with actually improving the articles, primarily by fine-tuning the phrasing and inserting proper references for existing content.

My position now is this: If someone — especially an anon — makes a significant edit without first discussing it on Talk, it should be reverted unless it cam be easily vetted by a regular contributor to the article. And if someone — especially an anon — keeps making essentially the same edit (rather than waiting for a resolution to a dispute), and repeating the same claims on Talk, then "protection" is warranted.

I would add that I'm adamantly opposed to Wiki's policy of permitting unregistered users' to edit content. It's THE fundamentally flaw in the whole Wiki project: it provides the means for rampant vandalism, wastes immeasurable quantities of registered users time, and severely undermines Wiki's value as a source of reliable information (thus the torrents of derision commonly hurled our way). Cheers, Rico402 (talk) 12:57, 2 August 2009 (UTC)

I'm more resigned to it, and don't find that semi-protection is much of a useful strategy; in fact, I generally have more troubles with registered user than with anons. At least with them you can sometimes feel like you're addressing someone real. Dicklyon (talk) 22:25, 2 August 2009 (UTC)

On the other hand the image dissector designed, invented, or whatever by whoever is the first stage in and a main part of the image orthicon and the image isocon, which were later replaced by the vidicon and similar tubes around 1950 or 1960. But the magnetic focusing for video camera tubes invented by Farnsworth in 1928 --via a long focusing coil placed along the tube-- survived the image orthicon era and it was a main ingredient in the vidicon and similar tubes; see the vidicon's diagram in the article. Thus Farnsworth's magnetic focusing was extensively used from the famous press conference in 1928 until 1990 or so. I suppose that Farnsworth did not earn royalties for the whole 70 years, but the fact is that Farnsworth was the first one in patenting a video camera tube with magnetic focusing. I will send an explicit reference as soon as I can find the book where I read this. --189.216.206.234 (talk) 18:05, 1 August 2009 (UTC)

Yes, that's worth a mention, if you find it in sources. Dicklyon (talk) 20:59, 1 August 2009 (UTC)

As I noted above, I'm willing to admit the error of my ways — mistakenly relying on Farnsworth's later patent re electron beam focusing in his image dissector. Shame on me. :(

But I'm not willing to give credit to Dieckmann and Hell (and apparently now Campbell-Swinton) for inventing the first practical imaging tube.

Re "what other historians have already concluded", you have to be very cautious here, because some authors may have an agenda, however subtle, and much source material (i.e., popular magazines) is simply not reliable. We must rely on "authoritative" reference material lacking in biased interpretation. Even so, with a couple dozen solid references you're still bound to find conflicting accounts, interpretations and opinions. So we must suss out the unbiased "consensus view". (Is the entire earth warming at a rate sufficient to cause global calamity by the end of the century, with anthropogenic forcing as a primary cause, as is the "consensus view" of the world's climate scientists? Or is George Will correct that the scientists are just a bunch of "global warming alarmists" advocating a mess of unwarranted and economically detrimental environmental policies. You see the problem inherent in selective research.)

Cheers, Rico402 (talk) 21:52, 2 August 2009 (UTC)

Sure, but to talk about how reliable a source is, or what points of view we should represent, you need to first get some sources cited. And primary sources pretty much don't count in situations like this. So far, we don't have much in the way of sourced alternative points of view to discuss, so it should be easy to just take out unsourced junk and move forward with sourced stuff. And I don't think our goal can be to suss out a consensus view, in a field like this where there may not be one; rather, we need to fairly represent all POVs when we encounter conflicts between them. I certainly agree that nobody had a "practical" view tube before Farnsworth's image dissector, and haven't seen any source suggest otherwise. Dicklyon (talk) 22:25, 2 August 2009 (UTC)

I assume you're talking about POVs in reliable source material. Even so, not all such POVs are worthy of inclusion. There is consensus on many of the major issues: Baird demonstrated the first working system, Farnsworth the first fully electronic system, Zworykin had a lot of help with the iconoscope, etc. But then an anonymous editor inserts, "The image dissector was nevertheless the first practical all-electronic video camera tube filed for patent by Dieckmann and Hell in 1925", citing the patent, then trying to back it up with refs citing Farnsworth's design as "identical". Dieckmann & Hell's 1925 design never produced an image, much less was "practical". But here we are wasting time reverting edits and hashing through this because an anonymous editor wants to undermine Farnsworth's work and give priority to Campbell-Swinton and Dieckmann & Hell. There's a biased agenda at work here, and the first indication was a major edit to the article. That's unacceptable. Such edits should be discussed here, before they show up in the article. Cheers, Rico402 (talk) 17:16, 3 August 2009 (UTC)

Proposed text again

It would probably be best to just omite the primary sources (patent links) altogether, and focus on the historical analysis. I don't see that your sources support the statement "Some authors consider that the same idea had been previously conceived by Max Dieckmann and Rudolf Hell." What the sources show is that they filed a bit earlier for a patent on a related idea; but not quite the same idea, apparently, as they didn't make it work, while Farnsworth did. So that sentence should be at least revised accordingly.

If you'd make an account or otherwise alert us when you're using different IP addresses, I wouldn't be reverted so many of your changes to talk page comments. Dicklyon (talk) 06:43, 4 August 2009 (UTC)

Sorry, I should have write that they conceived the same idea. Indeed there is no point to say that Dieckmann and Hell ever had a practical working device, Hell himself said so in 1951, he could not get any tube working properly. Nevertheless one can have and idea without being able to develop it into a working device. --148.247.186.142 (talk) 17:03, 4 August 2009 (UTC)

First of all, as this is the English version of Wikipedia, aside from the occasional friendly "quip", all comments should appear in English. Secondly, anyone who closes his comments with, "Good Night, You Deceitful People" ("Gute Nacht, Du falsche Welt") doesn't deserve a response. (As this remark is credited to "Papageno", it may not have been courtesy of 189.217.12.126, but that appears unlikely -- there's no bot signing comment attributing it to anyone else.) This is the kind of abusive behavior I was commenting on earlier; it's unconstructive and violates Wiki guidelines.

Rico, do you know that you are really special? You are the first person that I know who can get offended by an opera. "Gute Nacht, Du falsche Welt" is the phrase that Papageno says before trying to hang himself up in Mozart Opera the Magic Flute. And it is a very good way to say: Good Night... you deceitful world. Notice that I never said: "Ihr falsche Leute", which is indeed offensive. --148.247.186.142 (talk) 17:03, 4 August 2009 (UTC)

Aside from that, it seems we're getting into a more expansive history of the ID which perhaps would be better explored on the Image Dissector page. And I don't think there's much debate that Dieckmann and Hell "conceived" the idea of an "electron image" (as plenty of others did), but "previously" doesn't hold up; remember Farnsworth "conceived" of a fully electronic transmitting tube in 1920, just shy of age 14 (and drew a sketch of a well thought out design for his chemistry teacher 2 years later). It just doesn't appear that Dieckmann and Hell added anything substantive to the ultimate development of a working system. Maybe I'm wrong; but if so, then what specifically did they contribute to the work of others who would eventually find success? In what successful designs is there work cited?

Rico, answering your question. The journal Popular Radio published in May 1928 (volume 13) two photos and a diagram of Dieckmann and Hell's Image Dissector. So that Farnsworth surely increased his research efforts knowing that he had another competitor besides Zworykin.--148.247.186.142 (talk) 19:56, 4 August 2009 (UTC)

Btw, I see we're missing a key Farnsworth patent in the refs, the one that actually bears the title "Image Dissector": Farnsworth , Philo T., "Image Dissector", No. 2087683, U.S. Patent Office, filed 1933-04-26, issued 1937-07-20. I guess I'll insert it later, unless someone beats me to it.

So what do ya think, Dicklyon, would this much history be better left to the "History" section of the Image Dissector page? Cheers, Rico402 (talk) 09:31, 4 August 2009 (UTC)

PS: I agree that's it's best to "focus on the historical analysis" rather on patents; they exist after all to establish legal priority, and thus "property rights", not a historical account. (I'm sure we agree that the patent record often doesn't conform to who really invented what, and when he did so.) But should not at least a few be cited in addition to sources providing "the historical analysis"? For instance, the D&H 1925 patent seems to represent the first use of the term "image dissector", and Farnsworth's 1937 patent may represent the first fully realized version of such a device. I guess what I'm saying is, if we cite it (the patent) in the text (and of course if we quote from it), then it should be referenced in an in-line citation, but not as the primary source materiel for history, operational details, useful applications, etc. (I've been guilty of that myself.) Does this comport with you view? Cheers, Rico402 (talk) 12:11, 4 August 2009 (UTC)

Yes, it's OK to mention and cite patents that have been judged to be historically important (which is probably all of them in this case), but not to use those citations as direct support for historical statements about priority and invention except where backed up by secondary sources. Probably it would be best as you say to get the detailed history right at image dissector first, then summarize here. Dicklyon (talk) 15:22, 4 August 2009 (UTC)

OK -- seems we're pretty much in agreement. I'll support whatever you think is best. Cheers, Rico402 (talk) 05:41, 5 August 2009 (UTC)

Vidicon not a RCA invention - captured German technology

"A vidicon tube (sometimes called a hivicon 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"

Totally wrong! What you call a Vidicon tube was invented and built (perfectly working!) during WWII by German scientist Walter Heimann and others. Since this new kind of camera made use of the "inner photo effect" or electric resistance of a photo-sensitive semi-conductor material instead of the until then used "outter photo effect", the new type of camera was called Resistron in Germany. Cameras of this type were also used in prototypes of a "fire and forget" version of the Ruhrstahl-Kramer X-7 anti-tank missile, which was guided by a simplified electronic contrast method onboard the missile.

Captured by US troops at the end of the war, the Resistron camera eventually had been kind of "re-invented" under the name Vidicon at RCA.

That is why Walter Heimann, who is mentioned in the article under the topic "Pasecon", among others lost all his rights in "his" camera. He almost starved to death under US occupation, which took place until 1948!

Later, he further developed and improved his former camera to a the new type of camera, called Pasecon (as mentioned in the article).

The Pasecon camera (as far as I know it) improved the quality of (fast) motion in the television picture. This has been (and propably still is?) an old problem of Vidicon cameras, which therefore had been (and still are?) mainly used for industrial and surveillance purposes.

Unfortunately, I can't give you any citations or links for my remarks, since all documents - like so many other documents of German WWII technology - had been captured and taken away by allied troops by the end and after the war. That's propably the reason, why the whole resistron issue has almost been forgotten in Germany until recently.

Dissector tube: Diekmann and Hell vs. Farnsworth

Max Diekmann and his assistant Rudolf Hell patented their dissector tube in 1925 (recognized and confirmed by the German patent office in 1927).

Here is the link to a online source of the patent:

http://v3.espacenet.com/publicationDetails/originalDocument?CC=DE&NR=450187C&KC=C&FT=D&date=19271003&DB=EPODOC&locale=en_V3

Please copy and paste in your browser's adress line!

Diekmann and Hell also patented a CRT flying-spot scanner the year before (1924).

They also built a working dissector tube camera in 1925 and were able to receive low quality moving "shadow pictures" on a CRT display.

So, this has definitely been the world's first all-electronic television demonstration, no matter how you judge the picture quality!!

As mentioned, the quality was not very good. According to a interview with Rudolf Hell from the 1950s, the reason for this bad quality had been a lack of knowledge of how to focus the electron flow within the video tube by magnetic means. That's why Diekmann and Hell stopped working on their dissector tube and kept on using mechanical cameras for their further public television demonstrations in 1925. As far as I know, they both completely finished working on the field of television by the end of that year and both went different ways: Hell became the "Edison of the graphical (print) industry" and professor Diekmann a pioneer in radio communication and navigation, radio weather measuring and radar for the young aviation industry. He even tested prototypes of magnetron based short-wave radar devices as early as 1929 at his research facility in Oberpfaffenhofen near Munich.

Now it is getting interesting: The reason why Diekmann and Hell failed to build better dissector tubes in 1925 (due to problems with magnetic focusing), which would later be achieved by Farnsworth, is due to just one fact: the technological field of electron optics was yet unknown in 1925. This was to change the following year (when Diekmann and Hell had already separated from the field of television and from each other) when German scientist Hans Busch constituted the new field of electron optics (magnetic lenses, etc.) in 1926. So it was Busch, who paved the way for efficient video camera tubes and night vision devices. Technologies that were already being thought about up to this date, but were inefficient and, if at all, could only provide poor quality until Busch's discoveries and inventions. (electron microscopy is also based on Busch's electron optics) So it is no wonder that Farnsworth's developments on dissector tubes - allegedly from 1927 on - progressed while Diekmann's and Hell's didn't so in 1925!

A final word on the Farnsworth controversy: I have read some years ago that the US university and responsible professor, which/who administrates, archives and analyses Farnsworth's voluminous allowance, denies that Farnsworth was working on video camera tubes as early as 1927. He argues that Farnsworth did not begin work on that kind of technology before 1929. Could this be confirmed by anyone? If this would be true, all those people who claim the year 1927 for Farnsworth's all-electronic television would propably be wrong and maybe being taken in by a patriotic US hype. A message that is being repeated so often that it turns into truth (George Orwell)

Anyhow, the dissector/video camera tube will always be tightly linked to his name - but propably not exclusively.

Greetings! —Preceding unsigned comment added by 84.157.119.203 (talk) 23:41, 5 August 2009 (UTC)

The 1925 patent is old news, discussed above and in the article (with a link). But what source says Dieckmann and Hell transmitted "low quality moving 'shadow pictures'" in 1925?

Re: "... denies that Farnsworth was working on video camera tubes as early as 1927. Could this be confirmed by anyone?"

It can certainly be refuted. Between Jan. 1927 and April 28, Farnsworth filed 3 separate US patent applications relating to electronic imaging tubes for television: no. 1773980 filed 1927-01-07 (issued 1930-04-26), no. 1970036 filed 1928-0109 (issued 1934-0814) and no. 1986330 1928-04-17 (issued 1935-0-101). And there's plenty of other documentation re the experiments and demonstrations.

But the Busch stuff might shed some new light if it can sourced. Cheers, Rico402 (talk) 09:45, 6 August 2009 (UTC)

Vidicon reorganization?

Reading through a couple times, it seems like everything after the "Vidicon" section should probably be part of the "Vidicon" section. The plumbicons and saticons and whatnot are all just types of vidicons, right? 24.174.30.146 (talk) 03:56, 16 August 2009 (UTC)

Yup. They differ only in the chemical composition of the photosensitive layer. 76.27.195.28 (talk) 05:30, 16 August 2009 (UTC)

Dissector Tubes, Goebel's books.

The following reference to the image dissector tube built by Dieckmann and Hell can be found in page 279 of Gerhart Goebel's book: Das Fernsehen in Deutschland bis zum Jahre 1945" [[4]] [[5]],

Mit einer von R. Hell hergestellten Musterröhre ließ sich zwar der Effekt grundsätzlich nachweisen; leider waren aber damals die Mittel der Elektronenoptik nur in der Grundzügen bekannt, so daß die erwünschte scharfe Abbildung des Kathodenbildes auf der Anode praktisch nicht erzielt werden konnte [148].

Textual translation:

With a model-tube built by R. Hell the effect did allow itself to be proved in principle; unfortunately at that time the field (means) of electron-optics was only known in its outlines, so that the desired sharp projection (illustration) of the cathodic-image in the anode could not be obtained in a practical case [148].

A copy of Goebel's book can be bought from Radio-Book-shop [[6]].

It is quite interesting to read how Rudolf Hell could not obtain the desired sharp projection of the cathodic-image in the anode, and to compare this fact against the description of the first images transmitted by Farnsworth before introducing the magnetic focusing [[7]] [[8]]:

A fuzzy, blurry, but wholly recognizable image of the black triangle instantly filled the center of the picture field. This was our first television picture! Phil and I gazed spell-bound for a while and then with a deep sense of satisfaction shook hands silently.

Could somebody please explain to me then why it is said in the main article that Farnsworth's device was first tested successfully in 1927, while Dieckmann and Hell's device never performed as claimed. Should it not be said the same for Dieckmann, Farnsworth and Hell (in alphabetic order) considering the fact that none of them could obtain a sharp image until Farnsworth introduced the magnetic focusing in 1928, and so he gave a press conference then?

--148.247.186.142 (talk) 21:25, 19 August 2009 (UTC)

Additions to the discussion page should appear as separate comments -- signed and dated as such, not merely appended to previous comments.

Re "please explain":

"Hell claimed in 1951 that he had made a tube but could not get it to function because of the inadequate knowledge of (in 1925) electron optics." (Burns, R. W., Television: An International History of the Formative Years, 1998, P. 360.)

The phrase "fuzzy, blurry, but wholly recognizable image" is quoted directly from George Everson's The story of Television: The Life of Philo T. Farnsworth (1949, p. 91). Everson's account is at odds with Elma Farnsworth's in Distant Vision: Romance and Discovery on an Invisible Frontier (1989, pp. 90-91). Everson was a financial backer, not part of the team at Farnsworth's lab, and was not present for the initial successful demonstration, which was conducted using a glass slide with a single black line, not a triangle as Everson claims. (Perhaps he was recalling a previous or subsequent demonstration.)

E.F. describes the demonstration thus (p. 90):

An unmistakable line appeared across the bluish square of light on the end of the Oscillite tube. It was fuzzy at first, but Phil adjusted the focusing the coil, and the line became well defined.

"Turn the slide a quarter turn, Cliff," Phil instructed. Sure enough, the received line followed suit, turning 90 degrees.

According to E.F., George Everson arrived a short time later, and the demonstration was repeated (p. 91). This accounts for Paul Schatzkin's description of Everson witnessing the demonstration in The Boy Who Invented Television (2002, p. 54), where he notes:

Earlier that evening, Cliff Gardener dropped the glass slide between the Image Dissector and the hot, bright, carbon arc lamp. In the adjacent room, Phil, Pem and George watched the face of the receiver as it flickered and bounced for a moment. When the system settled down, all present could see the straight-line image shimmering boldly in an eerie electronic hue on the bottom of Farnsworth's magic tubes. When Cliff rotated the slide, everybody could see the image on the receiver rotate as well.

Everson had viewed the second successful demonstration that day.

The overriding import of the accounts is that on 7 Sept. 1927, a clear moving image was for the first time transmitted and received in real time by fully electronic means. Dieckmann and Hell had no such success. Rico402 (talk) 10:41, 21 August 2009 (UTC)

Addendum: According to Burns (pp. 360-361), "The principal difference between the operation of the camera tubes concerned the method of scanning: Farnsworth used electric fields, Dieckmann and Hell employed Magnetic fields." Therefore, the designs could hardly have been "identical", as was previously inserted into the article. It's also important to note that, again according to Burns, "nether tube had any means of focusing the electron image." (p. 360, emphasis added.) Thus any claim that D&H's tube employed "magnet focusing" appears false. Rico402 (talk) 11:18, 21 August 2009 (UTC)

Just some questions:

1) Does that means that an adjustable focusing coil was used by Farnsworth in his experiment of September 7, 2007?

No. (And being familiar with the 1927 design, you you darn well it doesn't.) I would surmise she's referring to one or more of the coils in the oscillator circuits. Remember she was not an expert on the technical aspects of Farnsworth's designs. Rico402 (talk) 12:03, 24 August 2009 (UTC)

2) Who is claiming that Dieckmann and Hell's device employed "magnetic focusing"?, the main point is whether Dieckmann and Hell transmitted any image at all.

As far as I know, no one. Why would you ask? Rico402 (talk) 12:03, 24 August 2009 (UTC)

OK, I see it my previous comment. I think "magnetic focusing" in D&H's device had been inserted a while ago by an anon other than yourself, confusing it with "magnetic scanning". (Or perhaps I just imagined it.) Rico402 (talk) 12:33, 24 August 2009 (UTC)

3) Can you sustain with an independent reference your affirmation that Dieckmann and Hell did not have such a success?

The available documentation shows no record of any significant measure of success. The project was abandoned. The burden of proof is on others to prove they did successfully demonstrate their device. Rico402 (talk) 12:03, 24 August 2009 (UTC)

Because R.W. Burns sustains his affirmations with the reference number 37, which is a work of Abramson [[9]] [[10]]. Tracing back the references one learns that Abramson sustains his affirmations with the text written in page 279 of Goebel's book [[11]] [[12]], and which I have included above. Finally the reference number [148] mentioned in Goebel's book is an interview [[13]]. Therefore Burns and Abramson's affirmations are just interpretations of what was really said in the interview [148], and as it was mentioned before with very wise words: authors tend to be tendentious.

--148.247.186.142 (talk) 15:36, 21 August 2009 (UTC)

You will agree that the life of an historian would be much more easier, had we had all the primary sources. However, you would also agree that a lot of documentation was destroyed or stolen in and after the war, so that we must work with what we have. Having said that let us state which are the naked facts on which Dieckmann and Hell's case is based.

We have Dieckmann and Hell's German patent 450187 of 1925, and we also have Farnsworth U.S. patent 1773980 of 1927. Some authors would say that the previous patent are different, and some authors would say that they are the same; that is the personal opinion of every author. However the naked fact is that we have two patents, and that is it.

By the way it seems to be that Burns did not read Dieckmann and Hell's patent, because in the second page of the patent --between the lines 15 and 25-- it is said that two perpendicular electric or magnetic fields can be used for scanning the "Kathodenstrahlenbündel" across the anode: Durch zwei elektrische oder magnetische senkrecht zueinander orientierte Wechselfelder mit verschiedenen Frequenzen kann das Kathodenstrahlenbündels periodisch so bewegt werden, dass während einer Halbperiode des langsamen Wechselfeldes jeder Querschnittsteil des Kathodenstrahlenbündels einmal die Anode...

On the other hand we have an extract of the interview [148] in page 127 of Goebel's book. Some authors interpret this extract in one way, some authors do so in a different form; that is the personal opinion of each author. However the naked fact is that we have the original words in German, and so we can know what the original author wanted to say.

Maybe a new document will be found in the future that will give the final answer, but to me in this moment the seven lines of the interview [148] say a lot.

--148.247.186.142 (talk) 18:11, 21 August 2009 (UTC)

Authors who would say that the devices are "the same" are in error, considering that there's a fundamental difference in the method of manipulating the electron image; "similar" may be a correct assessment. And no one should be persuaded that the excerpt from Goebel proves that D&H successfully demonstrated their device; "proved in principle" makes no claim to a successful demonstration. That the desired effect "could not be obtained in a practical case" is very significant. (In tech circles there's a fundamental difference between "in principle" and "in practice".)

Btw, my admittedly crude translation of the first half of the Goebel quote differs somewhat significantly from yours:

"Mit einer von R. Hell hergestellten Musterröhre ließ sich zwar der Effekt grundsätzlich nachweisen;"

Your trans: "With a model-tube built by R. Hell the effect did allow itself to be proved in principle;"

My trans: "With a model-tube produced and presented by R. Hell the effect although is fundamentally demonstrated;"

Where do you see, "itself to be proved"? Does not "grundsätzlich nachweisen" translate to "fundamentally demonstrate"? That seems pretty straightforward. The effect was "fundamentally demonstrated"; there apparently was no successful transmission of an image, otherwise it would have been noted. Cheers, Rico402 (talk) 08:05, 22 August 2009 (UTC)

Re "Phil adjusted the focusing the coil..." on page 90 of Farnsworth, Distant Vision ...: This refers to adjustments made to the receiving tube, the "Oscillite", not the dissector tube. The Farnsworths were stationed at the receiving tube during the first successful transmission, while Cliff Gardner was at the dissector tube. Whether the Oscillite used "magnetic focusing" I don't know nor can I say whether the receiving device described in Television System (Jan. 1927, US1773980) and further described in Television Receiver (Nov. 1927, US1773981) is the Oscillite. In any case, the two patents specify no focusing magnets. Rico402 (talk) 11:37, 23 August 2009 (UTC)

Translation of Goebel book's paragraph

Dear Rico402

Thanks a lot for the information about the adjustments made to the receiving tube, it has been quite interesting. In reference to the German translation, here there are some observations:

1) "Mit einer von R. Hell hergestellten Musterröhre" means: With a model-tube built (or constructed) by R. Hell.

2) "ließ sich zwar ... nachweisen" means: did allow (or let) itself ... to prove (and the action is true). Ließ is the past tense of the auxiliary verb "lassen"; sich is the reflexive pronoun: himself, herself, or itself; nachweisen is the main verb in infinitive; and zwar is a particle used to indicate that the action is true, like if I say: I do eat it (Ich esse es zwar)

3) "Grundsätzlich" means: in principle. The main verb is in infinitive and at the end because there is an auxiliary verb, and the auxiliary verb "ließ" is before the main subject "der Effect" because the statement begins with a pronominal part. Like if I say: Tomorrow will I an apple eat; maybe you would want to take a look to German sentence structure or German verbs.

I just make some observations, so that everyone is open to analyse them. But then again, I am insisting that the right translation is: "... the effect did allow (indeed allowed) itself to be proved in principle". The use of the first person (I or we) in formal German is considered quite arrogant, not even the diplomatic "we" is accepted, so that a passive or indirect form is used instead. That is the reason why it is said: With a model-tube built by R. Hell the effect did allow itself to be proved in principle; (Mit einer von R. Hell hergestellten Musterröhre ließ sich zwar der Effekt grundsätzlich nachweisen;).

Instead of: We did prove the effect in principle with a model-tube built by R. Hell ("Wir wußte der Effect zwar grundsätzlich mit einer Musterröhre hergestellten von R. Hell nach). This expression sounds really arrogant in formal German; and well "nachwußte" is a separable verb, so that "nach" goes to the end.

On the other hand I am not going to discuse whether the right adjetive for denoting Dieckmann-Hell and Farnsworth inventions should be "the same" or "similar", I am just going to point out again that Dieckmann and Hell's DE 450187 patent says in the second page --between the lines 15 and 25-- that two perpendicular electric or magnetic fields can be used for scanning the "Kathodenstrahlenbündel" across the anode, while Farnsworth's US patent 1773980 says in the first page --between lines 85 and 95-- that: there is then imposed upon the electrical discharge a plurality of electrical potentials of different frequencies for causing the electrical discharge to bend in-two directions, whereby the electrons from each elementary portion of the sensitive plate are successively directed through said shutter.

Sincerely yours:

"The Germans have an inhuman way of cutting up their verbs. Now a verb has a hard time enough of it in this world when it's all together. It's downright inhuman to split it up. But that's just what those Germans do. They take part of a verb and put it down here, like a stake, and they take the other part of it and put it away over yonder like another stake, and between these two limits they just shovel in German."

-- Mark Twain, from "Disappearance of Literature".

Postdate: Rico426 and Dicklyon. Should we not clean some of the paragraph above in order to make a bettee presentation of the on-going discution?

--148.247.186.142 (talk) 18:26, 24 August 2009 (UTC)

OK, but as I mentioned above, according to your translation -- "the effect did allow itself to be proved in principle" but "could not be obtained in a practical case" -- argues against a successful demonstration, i.e., the transmission of a moving image. As an aside, by highlighting the fact that D&H's design could employ "electric or magnetic fields" for scanning while Farnsworth's specified "electrical potentials", are you not indeed asserting that the two designs were fundamentally different (in manner of operation, if not in basic function)?

Btw, I think Twain had backwards, for in the German language is it not common to merge existing words to create new ones, which are in themselves essentially self-defined. (Then I suppose slicing them up again, per Twain's comment.) Rico402 (talk) 09:18, 26 August 2009 (UTC)

Dear Rico402.

It has been quite a pleasure to have this conversation with you, but unfortunately I have to leave and be away for one month. Believe it or not, I agree with you that Dieckmann and Hell did not build an image dissector tube that could be use in a practical case; and that is openly said in page 279 of Goebel's book:

Mit einer von R. Hell hergestellten Musterröhre ließ sich zwar der Effekt grundsätzlich nachweisen; leider waren aber damals die Mittel der Elektronenoptik nur in der Grundzügen bekannt, so daß die erwünschte scharfe Abbildung des Kathodenbildes auf der Anode praktisch nicht erzielt werden konnte [148].

It would be a mistake to try to comprehend the exact meaning of the words "grundsaetzlch" and "praktisch" according to modern American English, for the interview was done more than fifty years ago, and language has evolved a lot in the last years. Nevertheless we can be sure from the interview that a Model-tube was built by R. Hell, that at least one image was transmitted so that "Der Effekt" was proved in principle, but the quality of what it was transmitted was so bad in comparison to the images produced by the mechanical devices of that time that Hell's model-tube could not be use in any practical case. Whether Dieckmann and Hell transmitted a moving image or not, we cannot say, for even a moving image whose quality was inferior to those transmitted by a mechanical device could not be consider practical.

Therefore none can take away from Farnsworth the glory of being the first person in transmitting an image by all-electronic means whose quality was superior to those being transmitted by the mechanical devices of his time. It is clear that the image transmitted by Dieckmann and Hell was of inferior quality, otherwise they would have continued developing the image dissector tube instead of going back to work with the mechanical devices. The same could be said about the image supposedly transmitted by Zworykin in 1925. Let us assume for some moments that Zworykin did transmit an image in 1925, had this image been of good quality, he would have continued developing that tube.

Finally I do not really think it is a good idea to say in the main article that an image dissector tube must have deflection plates, for that implies that these tubes must use scanning by electric fields, and this fact excludes almost all the dissector tubes invented by Farnsworth, like that in the U.S. patent 1986330. I do not know whether you would want to mention the scanning by electric fields in order to state that there is a difference between Farnsworth and Dieckmann-Hell's image dissector tubes, but I think this is a dead-end-alley, for Dieckmann and Hell called for scanning via electric or magnetic fields.

Then again, it has been a pleasure to have this conversation with you, but I have to leave.

Tschuss: --148.247.186.142 (talk) 18:14, 26 August 2009 (UTC)

The bit about "deflection plates" comes from Horowitz (p. 1000, "deflection electrodes"), but this is in the context of a discussion of current (or "modern") imaging devices, and the ID as a "variation" of the "image intensifier" (which uses an electrostatic lens) positioned ahead of a vidicon or CCD. But there's no mention of electrostatics or "deflection electrodes" in the definition in Jack & Tsatsulin, and the use of "magnetic fields" to "keep the electron image in focus" is specifically mentioned. I think it's safe to conclude that both definitions are limiting, and a broader definition would be more appropriate. And yeah, the bit about "deflection plates" in the opening paragraph should be deleted (too specific), and perhaps a discussion of the methods of focusing and deflecting the electron image added to the final paragraph. I'll do the former now, and the later as time and resources permit. Cheers!, Rico402 (talk) 09:49, 28 August 2009 (UTC)

Guillermo González Camarena system

I added a small mention to a color system that is more simple to the NTSC. There is a link to the patent of that system in the article Guillermo González Camarena.

I am not an electrical engineer capable understand and describe the whole system. I knew about it in a TV program about this invention I saw it in a B&W TV set. That program included a small demonstration of the system it was saw in color in my B&W TV set. They explained it is an optical illusion that allow us to see colors in a B&W TV by varying the frequency of light. I understood it as something similar to the mpeg sound compression system, but I am not sure, so I did not mentioned that in wikipedia.

If someone can understand that patent and extend the explanation it could improve this article. More over it maybe deserves a new article about this not widely known interesting system. —Preceding unsigned comment added by Elias (talk • contribs) 15:06, 16 February 2010 (UTC)

Camarena received a patent for a color-wheel television system in 1942, which allowed viewing of a color image on a B&W CRT. I have revised the section to reflect this, and to improve the technical explanation of the method. I haven't found any references indicating that Camarena developed any kind of TV system which would allow viewing a color image on a B&W CRT without a color wheel. If you have seen a color image demonstrated on a B&W TV without a color wheel, it probably wasn't Camarena who invented the method. Wildbear (talk) 08:35, 29 March 2010 (UTC)

Years ago, I read of an optical illusion (the Pulfrich effect? Not at all sure) in which white light when pulsed at some tens of Hz (as I recall), and probably in a (time) pattern, can create a perception of color. I think it was the basis of a novelty spinning top with a disc "rotor". The top surface carried concentric black and white bands of varying arc lengths, and iirc at certain speeds (enough to blur) the bands appeared colored; however, the colors were quite unsaturated. Regards, Nikevich (talk) 15:08, 31 March 2010 (UTC)

Low-velocity electron scanning beams

One of the authors has written that Farnsworth indeed built the device described in the US patent number 2,087,683 filed in 1933 [[14]], apparently the first one to employ a "low-velocity" electron scanning beam. However he is not presenting hard evidence of his affirmations.

The devices using a low-velocity electron scanning beam are so sensible that they can be used for outside broadcasting [[15]]. If Farnsworth ever built a fully functional model of his US patent 2,087,683 before 1937, why did he never announce that he was the first one in doing an outside broadcasting? The British invented the super-emitron [[16]] and the cps-emitron [[17]] [[18]] in 1934. 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 [[19]]. On the other hand Farnsworth invented the low-velocity electron scanning beam in April 1933, but he was never able to directly broadcast anything from an exterior location, anything outside a well illuminated television studio.

The devices using a low velocity electron scanning beam produce images which are well focused in the center but blurry in the borders [[20]]. 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? The solution to this problem was found by the EMI engineer Lubszynski, who discovered in 1936 that a clear image could be produced if the trajectory of the low-velocity scanning beam was nearly perpendicular in a neighbourhood of the target [[21]] [[22]].

The 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 [[23]][[24]]. If Farnsworth ever built a fully functional model of his US patent 2,087,683, why did he never mention this kind of instability in his notes?

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 multipactor and electron multiplier image dissector? Search at google-patents [[25]] in order to discover that Farnsworth produced instead five patents for an image dissector with a miniature multipactor on March 12, 1935: Amplifier, Means for Electron Multiplication, Cathode Ray Tube, Detector, and Oscillator; and two patent for an image dissector with a multistage electron multiplier in 1937: Two-stage Electron Multiplier and Image Analizing and Dissecting Tube(signed by Gardner).

--148.247.186.142 (talk) 19:31, 4 March 2010 (UTC)

I agree with you, it seems to be that it is the same author who intentionally confuses the multipactor invented by Farnsworth in 1933 [[26]] [[27]] with the electron multiplier invented by Slepian in 1919 [[28]], and developed by Kubetsky [[29]], so as to be able to say that Farnsworth also invented the "electron multiplier". This author made the same affirmations in the wikipedia pages: history of television and image dissector. You and Rico402 have been doing an excellent job editing this page, and this new author is just trying to sex up Farnsworth work. The authors who sex up Tihanyi and Zworykin work are as nasty as those who sex up Farnsworth one. By the way, I hope you are not offended, but I made a pair of orthographic corrections; it is written devices and engineer. Take care.--189.216.228.103 (talk) 23:05, 4 March 2010 (UTC)

No, no, no... It's not devious at all. The editor was just trying to emphasis the improvement in sensitivity that the Farnsworth image dissector achieved by addition of what F called an "electron multiplier", and later a "multipactor". The confusion arises from that fact that F used "electron multiplier" to describe a device very different from the modern "continuous dynode" electron multiplier.

Please don't behave so harshly. This appears to be a rookie editor still learning the ropes; cut him some slack. I've given him a polite rebuke and just now some additional advice (see below). Let's keep it civil guys. Cheers, Rico402 (talk) 01:20, 14 March 2010 (UTC)

Recent edits erroneous, poorly sourced or POV

Several recent edits by Playerpage include material which is erroneous, poorly sourced or POV. There is simply too much wrong here to do selective editing. Indeed, I believe some of this material had previously been deleted, i.e., "second-generation Image Dissector in 1933" — this is erroneous and misleading; the 1933 patent entitled "Image Dissector" was not an ID as the the term is now defined, but a charge-storage CRT. Accordingly, the last 6 edits have been reverted.

I would suggest that Playerpage please make his case here on the Talk page before making any further edits. Cheers, Rico402 (talk) 14:47, 9 March 2010 (UTC)

---

This is Playerpage. As to my edits: I have done my best to stay to the history. As for POV, I am Farnsworth's sister's grandson, so, yeah, maybe there is some of that. But there is also some true knowledge of the first-hand intent of the inventions. The highly disputed "second generation image dissector" edit I made, which has been removed, I guess, referenced Philo's own intentions in creating it, whether or not they were fully realized.

As a couple of side notes: 1) Whenever I am forced to use Abramson as a reference I am very careful--because he always claims impartiality while quietly tearing down everyone but Zworykin. (Though I must ask: why were so many of my references removed, even when they used Abramson to back them up?) 2) With these many international patent disputes between Farnsworth and others, it should be noted that the U.S. is the only country that requires reduction to practice in order to issue a priority patent.

Farnsworth was the only inventor in all of those--even the American ones--who filed his patent AND made it work a few months thereafter. That was why he won priority.

Looking forward to the back and forth. playerpage (talk) 14:24, 13 March 2010 (UTC)

Hiya Playerpage... Thanks so much for the courteous response (not always the case around here). Please be advised that "original research" and "POV" are strictly prohibited on Wiki, so being Farnsworth's sister's grandson -- for which, by the way, you have every valid reason to be quite proud indeed (in the very best sense) -- puts you in a very difficult position. I respect that entirely, but unfortunately it makes you less than a totally objective critic, and may cast your views in a sometimes questionable light. The same is true for Kálmán Tihanyi's daughter, Katalin Tihanyi Glass, who has done exemplary work bringing her father's ground-breaking but often overlooked work to a wide audience. Unfortunately, an objective researcher can readily detect her over zealousness, often arguing positions which don't hold up under scrutiny (eg., essentially arguing that her father was the "real" inventor of the iconoscope; there's no evidence he ever actually built the television system and relevant devices described in his 1926 and 1928 patent applications, unlike Farnsworth and Zworykin's team at RCA.)

I don't believe I've ever disputed Farnsworth's priority when it was assured, although a couple others seem to be leaning very much that way. I'm onto them, and hope to shore up F's priority on a few contributions (eg., low-velocity scanning), but there's only so much time in a day or week I have to attend to this stuff. The whole subject can get very contentious; I had to have an editor "indefinitely banned" because he wouldn't stop aggressively (and abusively) asserting that Tihanyi was the undisputed "sole inventor" of electronic television, which is just patent nonsense. In the current situation, I believe we have a couple UK editors using anonymous IPs to undermine F's accomplishments and fundamental contributions to the field; I sincerely hope we can come to an amicable accommodation acceptable to all. (And I don't resent their many constructive edits, especially re the contributions of EMI and others.)

I have Abramson (1987) in hard copy and have examined all of your references, and quite frankly some of them just didn't hold up. That is, they didn't support the preceding content in the text. I believe I also have nearly all of Farnsworth's most relevant patents on hand as .pdf files for quick references (and ready access to those I don't via FreePatentsOnline, a much better archive than Google Patents as you can download the entire .pdf file), so I may have disputed a few things that referenced F's patents. There's perhaps a few other refs I found lacking, but I don't recall the specifics. I'm fairly certain the stuff I couldn't refute I left as is. Re the "second generation image dissector", it just isn't so; the accepted modern definition of "image dissector" doesn't apply to CRT-type designs.

Please keep in mind that, while I'm trying not to sound arrogant or "uppity", I'm a practiced researcher and technical writer with many years experience authoring and editing technical papers, so I can be brutal when the "facts" don't add up; quite often my reputation and that of my employers or clients was on the line, with often tens of thousands and even millions of dollars at stake based on my professional assessment of the relevant data.

Also, please be advised that I'm a Farnsworth champion. I've been an electronics buff since I was about 12 years old (1967), and had a fascination with television long before that, all my life really. (I hasten to add, however, that I am not an electronics engineer by degree or training. I'm a geologist, electrician, and sound reinforcement and recording engineer.) But I don't let my advocacy get in the way of what I can't authenticate.

I think if you just post you arguments here before hastening to edit the article, we'll get along just fine. Very good to here from you!

All the best, Rico402 (talk) 03:36, 14 March 2010 (UTC)

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Thanks Rico402, for the response. I too have the Abramson book in hard copy, but the difference is that my copy is all marked up in the margins--several chapters worth if it were to be written out, I suspect--by Grandma Laura (Philo's sis) with commentary on what is/isn't accurate and what is/isn't relevant. From there as well, I have gone through it myself and found many places where he seems to give credit or contradict or just plain ignore this or that contribution (and not just from Farnsworth) because of what I perceive to be his unconscious (or conscious) Zworykin-boosting.

I will use books like Abramson's for a reference, but I am constantly going back to personal memories of my interviews with family, or the written interviews my mother did before Agnes and Laura died a few years ago, as a higher authority. That may be why you thought my references "didn't hold up." I would see, for instance, Abramson's assertion that the low-velocity CRT "wasn't really an Image Dissector," but hey, that's what Uncle Philo called it, and the family-collected documents had nothing to assert that it was meant to be anything like Abramson claimed, so, especially knowing Abramson's penchant for extrapolation, I used him as an independent reference that the dissector EXISTED, and then asserted only that it was what it claimed: an Image Dissector. (This is also, incidentally, why I prefer "Distant Vision," though it is a bit sappy in its writing style.)

And Abramson is a historian (the only historian, I have found) who says there is "no proof" that that specal low velocity dissector was ever built--based on the fact that Philo didn't scream it from the rooftops, as it were. But he DID patent it, and it was never in Philo's pattern to patent things he did not reduce to practice.

So while so many other inventors are known only to have patents to their name, and yet we are told to believe that was good enough, in this one instance a man with hundreds of patents to his name--all of which were reduced to practice--is written off in the case of ONE patent that a historian who is not disposed to be on his side in the Zworykin/Farnsworth debate says he couldn't possibly have built, because he doesn't see any evidence that it was built. But the historical evidence shows that Farnsworth Builds What He Patents.

Great discussion. Send me a private message. I'd love to talk to you further. playerpage (talk) 15:24, 16 March 2010 (UTC)

Audio ("microphonic") sensitivity of vidicons

I didn't know about this, and don't doubt that it happened. However, the photoconductive film in a vidicon is deposited on the inside surface of the faceplate, and the faceplate is typically thick enough not to respond to any sounds that wouldn't cause instant deafness, I'd estimate. It does, after all, need to be more than rugged enough to withstand atmospheric pressure. Moreover, the lowest resonant frequency of the faceplate is very likely to be well into the ultrasonic range, because it's so stiff. There must be a different explanation, perhaps the electron gun?

I didn't want to just jump in and trash that paragraph, though! Regards, Nikevich (talk) 15:18, 31 March 2010 (UTC)

Image dissectors were made until comparatively recently

Unfortunately, I don't recall the name of the company; its primary business was probably fossil-fueled boilers (I don't think even their control systems, but, perhaps, burners?). (Foster-Wheeler? Babcock and Wilcox?) In any event, they were surely not what one would think of as an electronics manufacturer. However, the image dissector tube worked so remarkably well for monitoring the fire in a large industrial boiler that when such tubes were no longer made, they set up their own i.d. tube manufacturing operation just for making such tubes. They made them as late as perhaps 1975, and possibly even into the early 1980s! (Unfortunately, I don't recall when they finally quit, and have long forgotten where I read of this, but I'm sure of my essential information.)

Regards, Nikevich (talk) 15:29, 31 March 2010 (UTC)

http://www.earlytelevision.org/diamond_camera.html