비구면 광학계를 적용한 LED 조명의 광학성능 향상에 관한 연구

Abstract

Recently, light-emitting diodes (LEDs) have attracted much attention due to their superior characteristics to other conventional light sources e.g., low power consumption, long lifetime, less environmental pollution, and so on. The use of LEDs has been rapidly increasing and this trend is expected to continue in the future. Currently, spherical lenes are commonly employed for LED-lightning, which gives rise to many problems, that include low illuminance, unpleasant feelings in human eyes due to a yellow belt phenomenon, etc., inherent to spherical nature of the lens. In this thesis, improvement of LED-lightning performance by adopting an aspherical lens is reported. A commercially available lens design software Code VTM (Optical Research Associates) was used to design an aspherical lens for an LED-lightning system and the performance of the system before and after adopting the aspherical lens was analyzed using an illumination design software LightToolsTM (Optical Research Associates). The yellow belt phenomenon was confirmed and improvement of the optical performance of the LED-lightning system adopting the aspherical lens was predicted through the simulations. The aspherical lens was fabricated using a diamond turning machine and the performances of the LED-lightning system before and after adopting the aspherical lens were measured. It was experimentally observed that the yellow belt phenomenon was noticeably eliminated and the illuminance was increased by adopting the aspherical lens to the LED-lightning system.