My Vintage Iconoscope TV Camera Tube.
Вставка
- Опубліковано 17 бер 2022
- This 1940s Iconoscope tube is a real gem in my collection of vintage electronics and scientific instruments. The Iconoscope was the first real TV camera tube featuring charge storage. That is, between video scans, each microscopic dot on the image area was accumulating and and saving charge created by light falling on it, so an entire 1/30th of a second of light energy was used in the image capture rather than just sensing the light's energy during the microsecond instant while the electron beam was reading that point. It's unprecedented light sensitivity really made TV broadcasting practical, and was the beginning of a long line of TV camera storage tubes that lasted will into the 1990s when semiconductors replaced them. Its also an amazing piece of glass blowing and is one of the few tubes where you can easily see everything inside.
- Наука та технологія
Enjoyable and clear.
Thanks! That was one of my first videos - always thrilled when someone one looks at one of them!
That's a beautiful example of vacuum tube technology. I'm jealous.
It sure is! I was thrilled to get it. Imagine the glassblowing skills that it must have taken!
Thanks for explaining this so clearly! I finally understand those weird highlight artifacts that I was so curious about. Great video
Thanks! This was one of my first videos. Sometime I will have to redo it with my "newer" camera tubes (image orthicons, vidicons etc).
What a beautiful piece to have in your collection! I’ve seen the light trails from bright spots on a lot of video recorded in the 70’s and 80’s and now I understand the cause. Thanks!
Thanks! That one one of my earlier video and I should redo as I get better at it! Yes - a magnificinet piece of glasswork - and it would have been as hi-tech as it gets 70 or 80 years ago. I'm always amazed they ever got TV camera tubes like that working back then - the output signals so unbelievably low.
By the 1950s the Iconoscope tube was no longer used for television cameras. Although it was still used in some film chains (that convert slides and movie images from film to television signals)
In the 1960s a television pick up tube called a Vidicon, which operates on a very different principle, was improved enough for broadcast television cameras. The new tube used lead oxide as the light sensor and was called a Plumbicon.
The comet tails you saw are caused by a defect in the early Plumbicon tubes, and later versions greatly reduced this artifact by redesign of the electron gun for larger beam current needed to recharge the areas of the image that were overloaded by bight light.
In the modern world vacuum tube technology has given way to solid state imagers (CCD or MOS types) as the prior art would not have made tiny cellphone and dashcam camera sensors possible.
@@pstonard I wonder how many people today remember the "comet trails" as you so nicely described them. I'm an old TV show buff and you see that on some of the videotaped shows of the 70s.
I also have an Image Orthicon and a Vidicon (and a few of its variants in my collection). Its amazing how accessible the solid state sensors have made video and photography, but it somehow lacks the magic the old tube stuff had when capturing video was really special and not an everyday thing.
This was one of my first videos - I'm always glad when someone sees it who appreciates the old video camera tubes. Thanks for commenting!
@@ElectromagneticVideos Your Iconoscope tube is the smaller of the two produced in volume (roughly 4.5 inch, called 1848, the other was 6inch, called 1850) The smaller one was developed by RCA for military use, notable in the remote controlled bomber and the flying bomb, both ideas a bit ahead of their time and not a great success.
There were some serious technical problems; notably the output signal is from a capacitor coupling (the mica substrate) as you correctly stated, and therefore lacking a DC reference, which is very important in video signals that are inherently unipolar.
Also as the electron gun is off-axis to the scanned area, which has significant keystone distortion. This requires the horizontal scan (15,625kHz) size to be changed from top to bottom at frame rate (60Hz) as the beam scans.
Later use of the 1850 in film chains benefitted from a backlight behind the tube to lift the video signal up by allowing a small dark current. Typically, a type 47 bulb was fitted to shine into the rear glass.
I have seen specimens of late production 1850s with mask paint on the exterior. GE also made the 1850 (under RCA license?)
Your specimen is an "air tube" - the Getter flash is white (exhausted all the Barium metal) so it has/had a leak.
The two "wings" near the face plate with separate terminals are "Givers" that release the cesium vapor by electrical heating after the tube is pumped, sealed, and the "Getter" flashed. The metal wings direct the vapor towards the target.
Manufacture of the mosaic target, as you correctly said, is composed of tiny silver beads on mica. It was a closely guarded secret at RCA. Today we would call those "PIXELS", I suppose?
Which Britannica volume is that one in- the iconoscope and telescopes?
It was Vol 21 of the 1961 edition. My dad had bought it before I was born, so it was already outdated when I was old enough to read it. But without the internet or Wikipedia, it was a wonderful thing to have. My brother and I probably read every technical article in it - or at least as much of the articles that we could understand. In general the types of articles werent written to be as understandable as we are used to today.
@@ElectromagneticVideos Terrific! Thank you for the info and great video!
@@kelleyburney5143 Thanks so much - this was one of my first videos and I'm always pleased when someone watches it.
If you looking for that that particular Britannica with those photos, I would guess that any of the Britannicas published +/- 5 years of that one probably have much the same article. The technology did change too much in that time period and I dont thing they did frequent revisions either.