Digital Light Processing
For large-screen displays, there is Texas Instruments Inc.’s Digital Light Processing (DLP).
The core of this technology is a chip containing 1.3 million minute mirrors. A light shines on this chip and each mirror goes to either an on or off position to create the image — either directing a pixel of light at the screen, or leaving it black.
If it is on all the time, it is fully bright. But the mirror can switch between on and off several thousands of times per second. By varying the amount of time it spends in the on and off positions, it creates up to 1,024 levels of brightness. The technology is available as either a standalone projector or in a digital television format. A 60″ to 70″ diagonal screen is little more that a foot deep.
Bistable displays are useful for situations where the data doesn’t change very often. A primary drawback is that they can only display two colors, which is where the “bi” part of the name comes in. The “stable” part of the name describes the primary advantage.
Unlike other types of displays which constantly require a source of power, bistable displays only require energy to change the content. The image remains visible even after power is cut off. Bistable displays are useful for things like eBooks or in store signage, but not for anything with rapidly changing information.
Field Emission Displays (FED)
CRTs offer a bright image, but they are big and clunky. If you want a big screen, it uses all your desk space because of the distance the cathodes inside the picture tube need to be from the screen. The bigger the screen, the further back the cathodes.
LCDs solve the space problem, but are not as bright and have a limited viewing angle.
FEDs offer the best of both. Instead of having a single set of cathodes to paint the entire screen, they contain an array of cathodes each covering just a portion. This lets manufacturers create large CRT displays that are as thin as LCD monitors.