Abstract The delivered quantity of TFT-LCD of Taiwan is more than that of Japan in the first quarter 2002. It pushes Taiwan to the position of NO2 in the world, only next to Korea. Hence Taiwan government has included the TFT-LCD industries as the strategic industries to develop. In the near future, we can forecast that TFT-LCD will succeed the semi-con- ductor industry to stand for the star industry of Taiwan. It is expectable that the TFT-LCD industry will help developing our electronic industry and contribute to the national economy. Back Light Modules are the most important key components in this industry. Especially after the newly risen TFT-LCD causing the CRT substitution effect which will bring in considerable business opportunity. Aparently, to be a key component of TFT-LCD, the Back Light Modules industry will possess limitless opportunity. This thesis trying to take ¡§K¡¨ company as an example for exploring that how the traditional CRT components factory stride across to the TFT-LCD components---Back Light Modules industry. How to create the synergy and competitive advantages by using the current visible and invisible resources of the CRT components. By way of the benchmark enterprise to establish the challenge target and point out the superiority & inferiority of both parties clearly and also to analyse the opportunity and threat of ¡§K¡¨ company. Eventually, this thesis also trying to analyse what necks will be met and the strategies to break through on challenging the benchmark enterprise. Hoping it will be valuable to those enterprises that intended to invovle in these similar industries. The focus conclusions of this study will be as below: 1. Hi-tech industry will lose their competitiveness easily. Enterprise can¡¦t make their original industry a last-ditch defense. They should strid across to the newly industry actively and steadily to look for the hope of future in the newly industry. 2. Although the traditional industry have played an important role on the economic miracles in Taiwan, but we also have faced the keen competition from Main Land China as well as the newly risen industrialized countries. In addition to speculating on how to strengthen our competitiveness advantage to meet head on the local competition, we also need to conceive of the necessary stategies and overall arrangement to defeat Main Land China. 3. ¡§K¡¨ company has the sustained competitive advantages. Perhaps the prices offered maybe not the cheapest but combined with the excellent product and superior service quality that should make customers feel cheap and fine. 4. The labor¡¦s technical capability will be the key competitive weapon in the 21 century.

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.

This thesis proposes a novel driving circuit of the RGB light emitting diodes (LEDs) for the back-light source of the liquid crystal display. In stead of employing three dc-to-dc converters, a fly-back converter with three secondary windings is used to drive RGB-LED light bars. By adjusting the duty-ratio, the fly-back converter provides compromised voltages to RGB-LEDs in accordance with the operating modes of dimming control, so as to retain current magnitudes within the acceptable values. LEDs of three colors are dimmed by regulating the duty-ratios of three active power switches individually. By changing the ratio of the average currents of the three primary color LEDs, the color temperature range of driving can reach the requests of dimming control. As compared with a consumer product using the conventional driving circuit, the proposed circuit is obviously much simpler with less components and a higher efficiency.

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.

This thesis proposes a dimming approach with Double Pulse Width Modulation for equalizing the light output of the back light with light emitted diodes (LEDs) for large scale outdoor liquid crystal displays (LCDs). The approach compensates the difference among the LED light bars by adjusting the power outputs of converters according to the feedback of light strength from light sensors. With the proposed Double Pulse Width Modulation method, local brightness adjustment on the light bars can be made to provide a uniform light output and the dimming function for LCD can be retained. Experiments results made on a 46¡¨ LCD with four LED light bars demonstrate that the double pulse-width- modulation can provide uniformly in the light bar output. The experimental results show the proposed Double Pulse Width Modulation (DPWM) method can alleviate the problem from divergence of the light bars and thus can generate more uniform light output on LCDs.

There were three poly-Si TFT made by ELA, SLS, and HREC. The HREC TFT had better reliability than ELA TFT and SLS TFT under AC and hot carrier stress. And the effect of bending in SLS TFT was more obvious then ELA TFT, it provide us a better choose to develop a flexible TFT LCD. In poly-Si TFT, the photon current would decrease if there was a grain boundary in the channel. In all parameters include both manufacture and measurement the HREC TFT had better behaviors than ELA TFT and SLS TFT. But there also some shortcomings we must overcome include we muse growth a heat-retaining layer extra and must etch it and the poly-Si/heat-retaining etch rate and so on.

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.