WinkOsmosis
Banned
My friend found this site. I don't believe him or the site about Germans having nightvision during WWII.
Mirrored link
Original geocities URL (that won't stay up if you go to it): http://www.geocities.com/desertfox1891/nightfightingpanthers/nightfightingpanthers.htm
Is that for real? Did they have video cameras back then? The site says something about a convertor to change IR to visible light...
Edit: He found something... http://www.wonderquest.com/InfraredVision.htm
Mirrored link
Original geocities URL (that won't stay up if you go to it): http://www.geocities.com/desertfox1891/nightfightingpanthers/nightfightingpanthers.htm
Is that for real? Did they have video cameras back then? The site says something about a convertor to change IR to visible light...
Edit: He found something... http://www.wonderquest.com/InfraredVision.htm
An infrared night vision system senses heat radiated by things and produces a video picture of the heat scene. See figure. The gadget that senses the heat is a photocathode, similar to the one in a video camera, except it is sensitive to infrared radiation instead of visible light.
To understand photocathodes, consider how light and metals interact. When a photon (a small particle of light) hits a metal surface, it might kick out an electron. I say "might" because each metal needs a certain minimum amount of energy before it emits an electron. Infrared photons, however, have such puny energies they can only knock an electron out of special metals.
A heat-sensitive photocathode contains a very thin layer of such a metal coated on an optically flat piece of glass. A lens focuses heat from the scene you want to "see" onto the photocathode glass. The metal layer on the glass is so thin that when heat photons strike its front surface, they propel electrons from its back surface. It turns a pattern of heat into a corresponding pattern of electrons.
A high voltage flings the electrons at accelerating speeds against a phosphor-coated anode layer located very close. The electrons pick up so much energy in flight that they make the phosphor glow when they hit. This turns the pattern of electrons into a pattern of light. That's the picture you see.