dc.description.abstract | This thesis is mainly to study on a dual-reflector-type LED surgical task lighting with switchable color temperature. The shadowless surgical lamp to be developed belongs to a multi-module lamp, which is composed of a plurality of module units and each module unit is designed by several different LED chips. We adjust power to goal of switchable color temperature. Optical design goal: switch colour temperature range 3750K-5250K; central illuminance ? 176,000 lx; light field diameter D50 ? 200 mm and D50 ? 0.5 × D10; color rendering index Ra value ? 95; single mask and double masks of shadow dilution ?85% and 55%; depth of illumination ?100cm. The optical part of the lamp adopts the dual-reflector, and the preliminary outline got by the ray-trace method. Using the optical simulation software verified and optimized. In the surgical light module part, we first selected three kinds of LED chips, such as 3 blue LED chips, 4 green LED chips and 14 white LED chips, from Nichia Corporation′s 219B series. Then, we wrote a set of 21 LED array program. The program obtains a better arrangement of several kinds of light mixing effects; and then through the light mixing optimization system-mixing cavity and diffusing plate, the light mixing effect of the overall surgical lamp is improved, and the overall color uniformity is significantly improved. The multi-module surgical lamp is configured as a multi-module shadowless surgical luminaire of five module units according to the better result of the module unit mixing light, plus the central illuminance and the shadowless requirement of the surgical lamp specification, through the module unit Tilting 15 degrees to achieve shadow dilution and meeting the goal of illumination depth, and the entire fixture size is about 66.6cm.
Keywords: Surgical lamp, Switchable color temperature, High Color Rendering Index, Shadow dilution, LED chip, reflector | en_US |