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)

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)

Best wishes from the Anonymous Author, please find attached below some transcriptions taken from three books and two articles on the history of television talking about the works of Dr. Max Dieckmann, Dipl.-Ing. Rudolf Hell, and Inventor Philo Farnsworth. I hope you may take the best decision of your own after having this piece of information.

1) R.W. Burns, Television: an international history of the formative years [[4]], The Institution of Electrical Engineers, Science Museum (Great Britain), page 358 and 360.

---Unknown to Farnsworth when he filed his patent, two German workers, Dr M Dieckmann and Dipl Ing Hell had patented a similar camera tube on 5 April 1925. The patent was made public on 15 September 1927, about eight months after Farnsworth's application, and so the two patents were independent of each other. 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. Generally, camera and display tubes have a simpler internal electrode configuration when magnetic deflection is utilised since the coils are necessarily external to the tube. The photoemissive cathode surfaces of both tubes consisted of a coating of potassium, or rubidium, or sodium. Hell claimed in 1951 that he made a tube but could not get it to function because of the inadecuate knowledge (in 1925) of electron optics.

The same utterly irrelevant crap: "Unknown to Farnsworth"; "could not get it to function". So the significance is what? That someone filed a patent for a fundamentally unworkable device?

From Early Television: A Bibliographic Guide to 1940, George Shiers and May Shiers, ed. New York: Garland, 1996, p. 80.:

"An indication of the upsurge in the interest in television is seen in the number of patents listed: thirty-seven for 1925, thirty-one for 1926, more than four-fold the annual rate of disclosures for the previous six years." (Emphasis added.)

My goodness, we gotta get all these in the article right away! One can never have enough useless information (in an article about video camera tubes that actually work). Rico402 (talk) 08:27, 1 August 2009 (UTC)

2) Albert Abramson, The history of television, 1880 to 1941[[5]], page 97.

---The camera tube (which was later to be called an Image Dissector) was essentially the same as that of Max Dieckmann and Rudolff Hell. However, their patent had not yet been issued and, as often happens in the field of invention, was almost identical. Still, where Dieckmann failed to get his tube to operate, Farnsworth was to success...

Rubbish, regardless of what Abramson says: "essentially the same"; "almost identical". How curious that they could never get it to work. Have you seen the schematic of this silly thing? Rico402 (talk) 08:27, 1 August 2009 (UTC)

3) Albert Abramson, Zworykin, pioneer of television[[6]], page 54.

---In April 1925, Dr. Max Dieckmann and Rudolf Hell applied for a German patent on a unique camera tube which electrically converted the entire optical picture into an "electron image" instead of using a single electron beam to scan the target. It was a cold-cathode tube that used high voltage to free the electrons from the photoelectric plate. The electrical image thus produce would be moved sequentially by means of coils or plates across a single anode in an aperture. The current from this anode would be led to an amplifier and become the picture signal. This form of scanning of the image inspired the name "image dissector". While Dieckmann and Hell claimed to have built several tubes of this type, they had to admit later that they could never get any of them to work.

Precisely my point: they could never get any of them to work. Rico402 (talk) 08:27, 1 August 2009 (UTC)

4) J.D. McGee, The Contribution of A. A. Campbell Swinton, F.R.S., to Television, Notes Rec. R. Soc. Lond., 1977, 32[[7]], pp. 97.

---It is certainly true that without charge storage as now used in almost all television camera tubes it would be impossible to transmit television pictures except at unacceptably high levels of illumination. The image dissector tube, due to Dieckmann and Hell and later developed by Farnsworth, is the only alternative and it is inherently about four orders of magnitude less efficient.

"[D]ue to Dieckmann and Hell"?! The development of a working tube had little if anything to do with Dieckmann and Hell's little unsuccessful experiment. McGee just doesn't know what he's talking about. Rico402 (talk) 08:27, 1 August 2009 (UTC)

5) Malcolm Gladwell, The Televisionary, The Newyorker. [[8]]

--But this was Farnsworth's mistake, because television wasn't at all like the safety razor. It didn't belong to one person. May and Smith stumbled across photoconductivity, and inspired LeBlanc, who, in turn, inspired Swinton, and Swinton's idea inspired inventors around the world. Then there was Zworykin, of course, and his mentor Boris Rosing, and the team of Max Dieckmann and Rudolf Hell, in Germany, who tried to patent something in the mid-twenties that was virtually identical to the image dissector.

This "virtually identical" crap really gets around. (I.e., where do suppose Gladwell got phrase?) And who doesn't rely on The Newyorker for the most accurate and comprehensive account of developments in science and technology? :) Rico402 (talk) 08:27, 1 August 2009 (UTC)

Best wishes: Non vox, non votum, sed actum.--148.247.186.142 (talk) 19:06, 4 August 2009 (UTC)

And you can drop the faux polite routine. Rico402 (talk) 08:27, 1 August 2009 (UTC)

Logica falsa tuam philosophiam totam suffodiant. Thus I'm not persuaded by your arguments to credit Dieckmann and Hell with anything other than possibly coming up with a clever name for the device that every serious researcher in the field knew was needed for the realization of a fully electronic television system. Cheers, Rico402 (talk) 08:27, 1 August 2009 (UTC)

Magnetic Focusing

It is quite arrogant to say that the Farsnworth "Television system" included a much more advanced device for "the conversion and dissecting of light". Who says that?, advanced with respect to what?, where is the reference?

Let me point out George Everson book The story of television: the life of Philo T. Farnsworth[[9]] where it is textually said in page 91 that: We again went into the receiving room. Things were turned on again. The bluish field lighted up. Cliff put the slide in again. 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!

The real breakout come with the magnetic focusing, and Farnsworth knew that. Let me point out the following references.

No need; I'm willing to accept that this was my error — relying on the later patent. Shame on me. Cheers, Rico402 (talk) 11:17, 2 August 2009 (UTC)

1) The same George Everson book as two paragraphs above, in page 24 he says that: In thinking the matter through, Farnsworth concluded that unless he prevented it the electron image would unquestionably become blurred. His knowledge of optics told him that light beams could be focused; therefore, why could he not provide a magnetic lens, or solenoid, to control the electrons and keep the unseen electron image sharply focused? This magnetic fo-cusing was the second essential in the development of his tele-vision camera.

2) The same George Everson book again, in page 81 he says that: In his original conception of the magnetic lens Phil thought that as the current increased the focus would become sharper, but early experiments showed this was not the case. The focus sharpened to a certain strength, but then if more current was applied the image again became blurred.

This magnetic lens was another original contribution to electronics. It provided Farnsworth with an important patent in television scanning[[10]].

The design and placement of the magnetic coils around the dissector tube became an essential factor in the production of a clear, undistorted image.

3) R.W. Burns, Television: an international history of the formative years, in pages 360--361 says that: In April 1928 Farnsworth applied for a patent for an improved image dissector. The new device incorporated a long solenoid, in which the tube was placed, so as to establish a uniform logitudinal magnetic field along the axis of the image dissector. It is easy to show that an appropriate magnetic field enables the electronic image formed in the plane of the cathode to be focused in the plane of the aperture. Although the magnetic field configuration does not constitute an electron lens--- since it can neither focus a parallel beam of electrons nor produce a magnified or diminished image of an extended source of electrons---it does lead to a sharper images.[[11]]

Best wishes: Non vox, non votum, sed actum.

--148.247.186.142 (talk) 22:15, 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

Gentlemen, please find below a proposed text. I have not seen too many references to Burns book, but Abramson works are widely commented in other wikipedia pages.

In January 1927, Philo Farnsworth submitted an application to the U.S. patent office for a "Television System" based on the idea of electrically converting the entire optical picture into an "electron image" and scanning it sequentially by means of coils or plates across a single anode in an aperture.[[12]] Its first image was transmitted on September 7 of 1927, and a patent was issued in 1930.[[13]] Some authors consider that the same idea was also conceived by Max Dieckmann and Rudolf Hell, who submitted an application to the German patent office for a electronic imaging device they dubbed "Lichtelektrische Bildzerlegerroehre" ("photoelectric image dissector tube"), and for which a patent was issued in October 1927.[[14]][[15]] Hell said that he had made a tube, but could not get it to function properly due to an inadequate knowledge of electron optics.[[16]][[17]]

One of the first images transmitted by Farnsworth was: A fuzzy, blurry, but wholly recognizable image of [a] black triangle.[[18]][[19]] He had already analysed which effects could generate a blurry image, and immediately conceived a solution by deploying a "longitudinal magnetic field" in order to sharply focus the so-called "electron image".[[20]][[21]] The improved device was demonstrated to the press in 1928.[[22]][[23]] The introduction of an "electron multiplier" in 1930 made Farnsworth's "Dissector Tube"[[24]] the first practical version of a fully electronic imaging device (or "rasterizer") for television. Unfortunately, it had very poor light sensitivity, and was therefore primarily useful only where illumination was exceptionally high (typically over 685 cd/m²).[[25]]

--189.217.12.126 ([[User talk:189.217.12.126|talk]]) 06:09, 4 August 2009 (UTC)

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)

I like the idea, we might have two pages: Video camera tubes (working devices) with a purely technical description of only the practical devices listed by the date when a working model was announced in a press conference: Farnsworth's image dissector, Zworykin's iconoscope, McGee's emitron, image emitron, orthicon, image orthicon, image isocon, vidicon, plumbicon, et cetera, et cetera, et cetera. It would be a page about how the devices work, so no history about how the devices were conceived is included here, that means no 1923-1925's Zworykin patents, no Dieckmann, no Hell, no Tihanyi, no U.S. patent interference cases.

Since history is intricate, we could have a second page on History of the video camera tubes, with all the rest of the information about Campbell-Swinton, Schoultz, Dieckmann, Hell, Tihanyi, et cetera, et cetera, et cetera... Indeed we must include here Farnsworth patent [[26]], for it is perhaps the first patent where Farnsworth and Lippincott use the term "image dissector", they also give credit to Campbell-Swinton and Schoultz, and much more important, Farnsworth invents here the low-velocity electron-beam scanning.--148.247.186.142 (talk) 17:03, 4 August 2009 (UTC)

I think that's going too far. We have History of television already. It shouldn't be hard to incorporate some relevant history in this article. Dicklyon (talk) 17:17, 4 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)