An Optical Design Of Interior LED Spotlights Used By A Fresnel Lens

Since the late 19th century, electrical energy was widely used in lighting, the technology of electric illumination had undergone several technological revolution. The incandescent lamps, fluorescent lamps and high intensity discharge lamps had been invented and produced, and light-emitting diode(LED) which developed recently is called the fourth revolution of electrical energy because of the advantages of high photoelectric conversion efficiency, color temperature stability, small size, long life, energy saving and environmental protection. Now LED is widely used in large-full-color graphic display, status-display, logo lighting, backlight-display and so on.A Fresnel lens, removing the material layers between the two-side surfaces of a spherical len and maintain the curvature character, is obtained. Fresnel lens has a wide range of applications, especially on magnifying lens, collimators and solar concentrators, due to the advantages of small size, light weight, high transparency, easy processing, cheap and so on.A kind of LED spotlight with 3W total output power, which is based on a Fresnel lens, was designed. The focal distance independence zone of Fresnel lens's was mainly used in the second optical design, and aimed at optimizing and improving the uniformity of the viewing area. The lights passing through the lens was refracted into the target circle area with 1m diameter and 3m distance to the lamp, and is met the design requirements. A numerical optical simulation for the LED spotlight was carried out in Tracepro, the illuminating effect, the safety and the manufactory errors were investigated, and the result shows that our design is safe, reliable and executable.