Hisanori Yamaguchi

A reflective color STN‐LCD with a single polarizer and double retardation films

— A reflective color STN-LCD with a single polarizer and double retardation films has been investigated. The double retardation films arranged in front of the LC layer enabled the LCD to contain reflective electrodes inside the panel. This configuration achieves a bright image with no parallax. A new construction of a reflective STN-LCD with a single polarizer has been developed by means of our own method in which the color difference ΔE* as the optimizing parameter has been used. Further, RGB color filters have been newly designed for our reflective LCD, and an aluminum (Al) layer has been introduced as a reflective electrode. As a result, we have realized a 7.8-in.-diagonal reflective color STN-LCD (640 × 480) which has 15% reflectance, 14:1 contrast ratio, 4096-color capability, and sufficient color gamut. It has been confirmed that the single-polarizer reflective color STN-LCD has sufficient performance for mobile business tools. We believe that it will be a key device for this application.

Reflective color STN-LCD technologies

Reflective color STN-LCDs should be one of the most promising devices for mobile business tools (MBT), because the demand such as low cost, low power consumption, light weight and compact size is especially strong for this application. A reflective color STN-LCD with a single polarizer and double retardation films has been investigated. The double retardation films arranged in front of LC-layer enabled the LCD to contain reflective electrodes inside the panel. This configuration achieves the bright image with no parallax. A new construction of a reflective STN-LCD with a single polarizer has been decided by means of our own method in which the color difference (Delta) E* as the optimizing parameter has been used. Further, RGB color filters has been newly designed for our reflective LCD, and the aluminum (Al) layer has been introduced as reflective electrodes. As a result, we have realized 7.8-in.-diagonal refractive color STN-LCD(640 by 480) which has 15% reflectance, 1:14 contrast ratio, 4096 color capability and the sufficient color gamut. It has been confirmed that the single polarizer reflective color STN-LCD has sufficient enough performance for MBT use. We believe that it will be a key device for this application.