In this study, it was investigated about optical simulation in high brightness and high uniformity direct-type backlight design for medical application. Direct-type backlight has been used high-brightness backlight such as Medical LCD application. The key parameter in designing direct-type backlight was consists of three geometrical dimension such as the distance of two lamps, the gap of lamp and reflection plate and the number of lamps. It has many of variations in optical design and it causes the different properties in backlight system. It shows the best values of above parameters; 26mm of the distance of two lamps, 4.5mm of the gap of lamp and reflection plate and 16 lamps. And we produced the specimen as above condition, and acquired good result in backlight such as the value of the brightness is 6423 nit in center of emission area and less than 5% in brightness uniformity. It shows the effective ways of designing backlight system using optical simulation method for medical LCD application.

In this study, We studied design method to reduce scattering reflection by adding a three - dimensional structure to light guide plate of LED backlight widely used in small and portable devices. In order to improve the efficiency of the light-incident part, a three-dimensional structure is used in which a repetitive structure of a prism shape and a semi-cylindrical shape is repeatedly added to the light-entering face in light-guide plate. As a result of the study, it was found that uniform luminance values were obtained in the light-incident portion and the backlight when a repetitive pattern of a semi-cylindrical shape was added as compared with a case in which a prism shape was added. Particularly, when a rectangular lens with a semi-cylindrical shape is added, the average value of the total luminance is increased by about 15% from 7278 lm to 8324 lm as compared with a general light guide plate.

주위의 빛을 감지하는 CDS 광센서가 포함된 LED 백라이트 시스템을 이용하여 주위조명이 밝을 때는 꺼지고 어두울 때 켜지는 빛 감지형 액자를 개발하였다. LED 백라티으 회로를 삽입할 수 있도록 액자 내부에 충분한 공간을 두었으며 액자의 테두리는 LED 백라이트의 조명외 불필요한 사이드 빛을 가릴 수 있도록 액자를 제작하였다. LED 백라이트 시스템의 경우, 이상적인 경우 밝을 때는 0의 저항값을 가지고 어두울 때는 무한대의 저항값을 가지는 특성을 갖고 있는 CDS 광센서를 고속 스위칭 트랜지스터 베이스 단자에 연결하여 on / off 동작을 할 수 있도록 설계하였다. 직렬 및 병렬로 3×3의 배열로 연결된 9개의 LED들은 3개의 anodesms 전원에, 3개의 cathode는 트랜지스터의 컬렉터에 연결하여 on시에는 cathode가 접지와 연결되어 LED가 동작하였고, off시에는 floating상태가 LED가 동작하지 않았다. 밝은 조명하에서는 센서에 의해 LED 백라이트가 동작하지 않았고 어두울 때는 정상적으로 동작함을 확인하였다.

TFT-LCD is the most popular type of flat display panel in the information technology field. The back light unit is a main part of the structure of a TFT-LCD panel. Occasionally, studies have shown that failures of the CCFL of the BLU occur due to the poor weld characteristics of these materials. The aim of this study was to prepare some technical data and to characterize a microjoined electrode for the CCFL. Microstructure examinations, microhardness measurements, resistance measurements and microtensile tests of the microjoined electrode were carried out. The result indicates that a large amount of grain coarsening exists in the heat-affected zone (HAZ) of the weld between the cup and the pin. This grain coarsening of the HAZ between the cup and pin is caused by the welding cycle, which may have an influence on the lowest microhardness values. Fracturing of the microjoined electrode also occurred at the HAZ close to the cup between the weld holding the cup and the pin. Additionally, no specific changes of the electrical resistance among the cup, pin, and lead wire themselves or in the microjoined electrode were observed.