Abstract
LED backlights for LCD have many advantages against CCFL backlights. For example, better color reproducibility, longer life, higher efficiency, less power consumption, and Hg-free green product. Here we present the "hollow cavity" side-lit LED backlight unit. It is categorized as the third type of LED backlights. The hollow-cavity structure consists of a pair of LED/collimator units, a white bottom reflector and a top diffuser. We can provide a lightweight LED backlight unit because it does not have any light-guiding plates inside. A simple design-rule of the hollow-cavity backlight is formulated for the first time. The performance of 21" LED backlight unit fabricated based on this formulation is also presented.
