Matthew Zavracky

Miniature 1280 by 1024 active matrix liquid crystal displays

A miniature 1280 by 1024 transmissive active matrix liquid crystal display (AMLCD) was developed for the RAH-66 Comanche helicopter head-mounted displays and other military applications. The display has an active area of 15.4 mm by 12.3 mm with a diagonal of 19.7 mm (0.77 inches). The display has a 12 micrometer pixel pitch, yet a clear optical aperture of over 30% was achieved by using a 0.8 micrometer CMOS design rule for the active-matrix circuit fabrication. The fabrication process used was similar to that of Kopins commercial CyberDisplay AMLCDs, which produces high performance, high reliability devices. To achieve low temperature operation to -40 C, the display was designed with an integrated thermal sensor to allow control of a heater. Display test results include contrast ratios over 100, continuous gray scale, fast response times for 60 Hz operation, and the ability to show both gray-scale images and symbology at display luminescence levels over 2,000 foot- Lamberts brightness. This latter result will enable this display to be used in systems with full sunlight readability requirements. The design, fabrication, and characterization of this display are discussed.