Seiji Sakai

41.1: A Thin LED Backlight System with High Efficiency for Backlighting 22-in. TFT-LCDs

A TFT-LCD with RGB LED-Backlight has become well-known as wider color reproduction. By matching the transmissive spectra of color-filter to high-power red, green and blue (RGB) LEDs radiation, wider color reproduction and higher brightness have been achieved. But it has been difficult to mix the RGB light of high-power LEDs without a loss of light until the light is introduced into the LC-panel. We have developed a new LED-Backlight system that provides an optical efficiency of 72%. This efficiency is 1.4 times the previous LED-Backlight with a light guide. We applied this new LED-Backlight to a 22-in. XGA-Wide TFT-LCD and achieved a brightness of 540cd/m2 and color reproduction of 105%.

40.5L: Late-News Paper: 18.1-inch XGA TFT-LCD with Wide Color Reproduction using High Power LED-Backlighting

We develop 18.1-inch XGA TFT-LCD using high power Light Emitting Diodes (LEDs) as light sources for backlighting. By matching the transmissive spectra of color-filter to LEDs radiation, the higher brightness and the wider color reproduction of 95%-NTSC are achieved on the front-of-screen.

53.2: A Novel Optical System LED-Backlight with Excellent Brightness Uniformity for TFT-LCD

We have developed a new LED-backlight structure. By applying this new structure to a 12.1-inch SVGA TFT-LCD, the number of LEDs can be reduced approximately 60% compared with the conventional structure while keeping the same level of brightness uniformity.