I'm researching the active infrared viewing telescopes used by U.S. forces from 1944-1960. Their light assemblies used incandescent lamps with tungsten filaments. They used a glass filter coated with material that blocked visible light and allowed IR light to pass through the filter. The IR imaging tubes view IR at 800nm-1000nm. The filter's we are using were manufactured by American Optical in the mid 1950's and have worked with various different IR light sources.
The exception are the LED's that emit IR light in this spectrum.
If someone could explain why the LED generated IR will not pass through the filters we'd be very grateful.
Thanks
Jim
The exception are the LED's that emit IR light in this spectrum.
If someone could explain why the LED generated IR will not pass through the filters we'd be very grateful.
Thanks
Jim