The digital camera in your home shares a family tree with the James Webb Space Telescope. Webb's instruments use "detectors," similar to the sensors in digital cameras, to convert images into a digital signal.
The detectors being tested at the Jet Propulsion Laboratory in Pasadena, Calif., are part of the Mid-Infrared Instrument (MIRI). The detectors, which will be housed in insulated, brick-like structures called focal plane modules, go through intensive temperature and vibration testing to ensure they survive the ride into orbit. The detectors have to be perfectly aligned within these brick structures, so they don't move out of position when the chill of space causes materials to shrink. MIRI will be the most sensitive mid-infrared instrument ever flown in space, helping us see deeper into the universe than ever before.
Techonology Overview: Instruments
NASA's Webb instruments page
Images of Webb's detectors
NASA news feature: James Webb Space Telescope Testing to Find Infrared Light for Christmas
NASA news feature: Shake, Rattle and Roll: James Webb Telescope Components Pass Tests