Advancements in backlighting technologies for LCDs

摘要

Developments in backlighting technologies for LCDs based upon fluorescent lamps have substantially reduced the display module thickness and power consumption over the last 4 years. The present state-of-the-art in fluorescent backlighting is reviewed. Currently, there are two major categories of backlighting system design used extensively in graphic type LCD modules. These are back-lamped backlights and edge-lit or light-pipe backlights. Much of the recent design effort has focused on edge-lit backlights because of their superior lighting uniformity and reduced thickness as compared to the back-lamped type of system. In the past, edge-lit backlights suffered reduced lighting efficiency when compared to the back-lamped type. Also, edge-lit backlights tended to produce a lower total luminous output than back-lamped designs. Therefore, back-lamped backlights are often found in LCD modules requiring high brightness such as avionics/military applications and especially in color LCD modules. Edge-lit backlights predominate in commercial monochrome applications such as present day laptop computers. However, recent improvements in the design of edge-lit backlights have opened the way for this approach to be used in commercial color applications as well.