Polysilicon Active-Matrix Liquid Crystal Displays For Cockpit Applications

Abstract

Virtual image and cockpit applications require high resolution, high brightness, high contrast, full color displays with grayscale and which are also lightweight, small in size and have low power consumption. These requirements are well matched to active-matrix liquid-crystal flat-panel displays. In particular, polysilicon active-matrix displays with their high performance and capability for integrated scanners are ideal candidates to satisfy cockpit display requirements. A design analysis is presented for two types of avionic display, a 1-in x 1-in, 1000 x 1000 pixel helmet-mounted display, and a 8-in x 8-in, 1024 x 1024 sub-pixel color cockpit display. The analysis will show that the performance requirements for the display can be met with existing polysilicon device performance and current photolithography equipment. A screen brightness of 75 ft-L can be obtained for the cockpit display, using fluorescent lamp backlighting. Grayscale is obtained through on-plate digital circuitry. The feasibility of many of these concepts has been demonstrated in the design of a 192 x 192 active-matrix array with integrated data and select scanners. The design features of this array, as well as its performance will be presented. The display is capable of showing real-time color NTSC TV signals, with limited grayscale capability. The display operates with a 180 frame/sec refresh rate, while the shift registers operate at speeds up to 2 MHz.