The new technology of backlight is the key to the evolution of LCD TV

LCD TV to improve picture quality, reduce power consumption in the process of LCD, backlight play an increasingly important role. In the "FPDInternational2006 forum" D-5 seminar "back light (1)", from Holland PHILPS lighting, South Korea's Samsung advanced technology research institute (SAIT) and OSRAM's speakers introduced the latest developments in the field.

Improved full HD image quality by 120Hz driver and scan backlight

PHILPS lighting WandaKruijt details the relationship between image moving speed and resolution. In theory, it is shown that the frame rate can be improved from 60Hz to 120Hz. However, in order to play regular TV image display with full use of the resolution requires a very high frame rate, SD (standard definition), HD (hd) and full HD to 120Hz, 200Hz and 325Hz respectively.

As an alternative, WandaKruijt also introduces a scanning backlight. In full HD, for example, in the case of frame rate of 120Hz, the backlight needs to be reduced to 40% frames per frame time. The company achieved the goal by using a hot cathode tube (HCFL), which is capable of obtaining high light output power. HCFL prolongs the service life by controlling the temperature of the electrode.

Development of CNT backlight

SAIT YongwanJin discloses the development of carbon nanotube (CNT) backlight. The CNT backlight improves the service life by improving the driving mode, improves the brightness, luminous efficiency and NTSC ratio by improving the phosphor, and the luminous efficiency of the small test lamp is 46lm/W when the brightness is 10 thousand cd/m2.

YongwanJin pointed out that the CNT backlight has the characteristics of fast response and wide dimming range. And the scanning backlight, area control (local timing) and other image quality improvement technology is also very strong adaptability. The goal is to overcome the life, reliability and luminous efficiency and other issues, in 2 ~ 3 years into use.

LED way more power than CCFL

OSRAM's CWittmannChristian introduces a system that combines the use of high-power chip LED and optical lenses. From the 32 inch LCD TV power consumption, the backlight system using 135 LED is 138W (511cd/m2), when using the 180 LED is 105W (532cd/m2). The use of cold cathode tube (CCFL) is 110W (450cd/m2).

It may also be used by multiple low power LED (in) a back light structure, but compared with the use of high power LED, the less number of LED, easy to choose, and the circuit is very simple, so high reliability "(CWittmannChristian).

Source: Yesky