Recently liquid-crystal display (LCD) has the highest output value and most popular usage of flat panel display in monitor. The advantage of LCD is low electric quantity consumption, light quantity and thin thickness. LCD has substituted for the traditional screen monitor. The back light module, color filter and actuation IC are three major cost structures in LCD. The optical film is the most used structure in back light module, which is used to increase brightness, luminate evenly the panel and prove illuminant efficiency. The liquid crystal does not irradiate, therefore, the back light module is accessory of liquid crystal display, especially the LCD has advanced the size over 60 inches dimensions. When the panel enhances its size, the cost of back light module correspondently increase, even achieve to 50%. The importance of back light module in LCD can be understood. This study is to develop an innovation of gapless compound polygonal micro-lens. The manufacturing process includes lithography, reflow, electroforming and hot embossing technologies. Also the TracePro software is applied to facilitate the design. LED is used as the illuminant without diaphragm simulation. It enables the optical film to achieve an optimum condition. Using the gap optical film, we need to apply 3~4 pieces in the back light module. When we use the gapless optical film to make film to increase largely the light efficiency, we expect to use 1~2 pieces in the back light module. In this case it can reduce the cost and promote the competition of the domestic manufacturer.

LGP( Light Guide Plate) is the important part of the BLM(Back Light Modulus). It makes the BLM high illuminance and uniformity with leading light direction. LED(Light Emitting Diode) is the light source of the BLM. In this study there are V-Cut of the micro-structure applying on the LGP to discuss and research with optical simulation software TracePro. A 2.5 inch BLM with LED is building to analysis. First, the beginning side of the LGP has been studied with V-Cut. The purpose is making the distribution angel larger and upgrading brightness. Then, with the V-Cut micro-structure on the out-light surface and optical sheets get the largest light availability ratio. Finally, the reflect surface divides to five parts with different pitches design. The results show the good benefit by more uniformly light distribution and illuminance.

The research direction is to apply the precision machining and the micro-electroform technology on LCD back light module (BLM). The goal is to strengthen the BLM energy utility, increase the BLM brightness, and save the material cost. In experiments we adopted the ultra precise machining and the micro-electroform technology in the LGP mold processing in order to enhance the BLM brightness. Since both technologies are different from the commonly used etching processing way, therefore, this study will be aimed at the analysis on three different processing technology in LGP. Consider the general LGP reflecting surface as the etching way is the base-line data for BLM average brightness, the change of reflecting surface is the V-cut processing way. After injection the reflecting surface of LGP is convex V-cut that may increase 6% brightness in comparison with the etching way. However, the application of the micro-electroform way of injection the concave V-cut LGP may again promote 6% brightness in its optics performance. Therefore, the increase of micro-electroform processing, the BLM brightness promotes approximately 12% compared to the etching way. That may reduce the lens use of the BLM and achieve the economic efficiency in cost redution.

For a back-light module with multiple cold cathode fluorescent lamps (CCFLs) in mid-size or large size liquid crystal displays, a balance scheme must be included to have approximately equal currents among the lamps and hence to output equal brightness. In this thesis, a half-bridge inverter is adopted to drive multiple step-up transformers with the same turn ratio, in which the primary windings of the transformers are connected in series whereas the second windings drive CCFLs in parallel. Due to the series connection of the transformer sets, the current going through the primary windings is identical, so that the lamp currents from second windings tend to be equal. A driver circuit with the proposed scheme is designed for 8 U-type cold cathode fluorescent lamps in a 32-inch backlight module. The simulation and experimental results demonstrate the effectiveness of the balance scheme, even for the lamps operating at low current.