A high-brightness GaP green LED flat-panel device for character and TV display

High brightness green LED flat-panel display devices for character and TV displays have been developed by utilizing our automatic fabrication techniques. The picture elements of these devices are highly efficient GaP green LED's having an average external efficiency of 0.23 percent at 12.5 A/cm
²
with encapsulation. There are 6144 (96 × 64, matrix) picture elements mounted on the alumina substrate for a type I device, 17 920 (160 × 112, matrix) for a type II, and 38 400 (320 × 240, zigzag) for a type III. A reflective glass sheet, which has holes into which the LED's are fixed, is mounted on the alumina substrate in order to collect the light emitted from the LED's and reflect it efficiently for type I and II devices, but not for a type III device. Brightness (luminance) is 70 ft . L (240 cd) at 0.5 mA/dot for a type I device, 40 ft . L (137 cd) at 0.3 mA/dot for a type II, and 40 ft . L (137 cd) at 0.5 mA/dot for a type III. In this paper, fabrication techniques, and structures and characteristics of flat-panel devices for character and TV displays are reported.