Development of carbon nanotube field emitters in the backlight for liquid crystal display

Abstract

The carbon nanotube (CNT) field emitter based backlight unit (BLU) is highlighted as a device to improve video images for future television (TV) of liquid crystal display (LCD), especially in terms of contrast ratio and moving picture response time (MPRT). Recently, Samsung demonstrated [1,2] an LCD TV lit by a CNT-BLU with contrast over 1,000,000:1 and 4 ms MPRT. Also, its excellent dynamic controllability and low power consumption can be merits over other competing BLUs using conventional cold cathode fluorescent lamps (CCFLs) or recent light emitting diodes (LEDs). Due to the fact that the CNT emitters can be integrated even into an extremely fine gate structure [3], this new device using nano-emitters is supposed to make it possible to construct a future color-filterless LCD through so-called color field sequential technology. A color sequential driven LCD is expected fully to open up different display technologies including high luminance with low power consumption and improved color gamut, accompanied by total redesign of LCD panels. Moreover, we expect that LCD TV technology will be shifted from current high definition (HD, ~1000 pixels × 2000 pixels) to ultra definition (UD, ~2000 pixels × 4000 pixels). Under a UD environment, the aperture ratio in the LCD is estimated to be less than 25% of that of an HD panel, which limits the overall brightness and power consumption. The formation of CNT field emitters in BLU system is core technology in reducing production cost and improving the luminance performance.