Chapter 2

Abstract

Principles of LCD Illumination Systems As the expansion of TFT color LCDs, the LCD illumination systems of light weight, thin design, high luminance, and lower power consumption are required for more appealing applications. Conventionally, LCD illumination systems, i.e. LCD backlights, are composed of light source (Cold Cathode Fluorescent Lamp (CCFL) or Light Emitted Diode (LEDs)), reflector, lightguide, prism sheets, and diffuser sheets. In this chapter, we describe the principles of key components in LCD illumination embodiment. First, the working principle and the design of lightguide plate, shape and optical patterns, are discussed. Followed by characterizing the function of optical films, such as prism sheets, diffuser sheets, and polarizing sheets. Then, some concerned issues while designing the backlight systems are studied. Additionally, the simulated procedures are introduced to confirm that the proposed designs can meet the required properties of LCD illumination systems. Finally, a briefly summary will be given.