Abstract
The purpose of this research is to design a first-order（without other medium between lens and light source）lens of a high power light emitting diode(LED) for illumination. The manufacturing process of designed lens is also studied. The lens is designed to make the lights distributed on the objective surface as uniform as possible. The optical character of the light emitted from LED chip is lambertian emitting. The design algorithm of the light uniformity is obtained by means of reflection, total reflection and refraction. By using the optical mechanisms described above, we divided the light ray into small-angle ( light between optical axis ) light zone, and large-angle light zone. The computer is used to do the precise calculation to design the profile of the lens. To prove the design results is practical, several experiment are completed. In addition,, the production method is also considered. Considering the design of injection mold, the geometry and profile of the lens is modified and the optical performance of the modified lens is almost same as the original design. After the real lens fabricated, optical experiment is also proceeded. It is noted that due to the light of LED is not a point light source, therefore, the designed lens cannot reflect and refract every light ray in optimized way. It is necessary to use the optimum method to find the best lens profile.