Originally Posted by Crescent
I'm a hobbyist, not a pro like a lot of you. I was trying to explain a CRT projector to a buddy at work who did teach science at some point in his life. I was trying to tell him that the projector works the same way as a CRT TV only three times. He told me that there had to be a "lamp" in order to project an image. I said it was just an electron beam scanning back and forth in a tube for each color. Honestly, and it should be fairly obvious by how, I don't know exactly how it works. Is the tube lamp-like? I rejected this notion based on my knowledge of how black is produced.
How is the image projected? Politely now, what do I tell my buddy?
Layman's terms for me please.
There is no lamp. The best way to explain is with the silly fresnel scam things you see on ebay. There, you can purchase plans to "Trurn your TV into a giant screen!!!111eleventy!" Okay, now stay with me here.
All that scam is, is basically how to take a large lens (say from an overhead projector one of those things your teachers/professors used when you were falling asleep in lecture) and put it in front of your television. If you remember way back to high school physics and playing around with lenses, if you have a lens like this you can focus a plane onto another plane. Your television screen is just such a plane, and it's lit up. Put a giant lens in front of it, and you can focus it onto a wall. Now, the thing with a regular television is that it isn't very bright. If you actually do this, you are basically making your own DIY CRT projector: you have a CRT that makes an image, a lens, and you're projecting it onto something. Thing is, the image is going to suck, because the TV is way too dim, the lens is terrible, etc.
A CRT works basically exactly the same way. You have a CRT tube, and you have a lens, and it gets focused onto the screen. Except that you have three tubes instead of one, and they're quite bright. But there are no lightbulbs involved. There are just three very tiny monochrome televisions in there, basically. That is probably the best way to explain it to someone. If they don't understand, then you could explain about the magic gnomes...