The color enhancement and collimation features of the multi-colored LEDs with different periodic microstructure on the top surface of TIR lens

Abstract

Due to the advantages, such as high efficiency, power consumption reduction, no mercury, pure saturated color, high reliability and long lifetime, the solid-state lighting based on light-emitting diodes (LEDs) has become very popular at this stage. In the lighting applications such as spot lighting, downlighting, architectural and show lighting, the colortunable properties with collimating beam of LEDs are highly demanded. The color–tunable lighting is easily achieved using multi-colored LEDs instead of inefficient color filters. However, the applications of multi-colored LEDs usually appear the undesirable light patterns such as color separation or color fringes. At the meantime, the use of TIR (total internal reflection) lens for multi-colored LEDs to collimate the light from the LEDs with different color will introduce seriously undesirable artifacts. Thus, a periodic microstructure surface on the top surface of the TIR lens would be used to reshape the light from the different colored LED chips in the multi-colored LEDs, and then decrease the color separation and color nonuniformity. In this study, the TIR lens with periodic microstructure surface on the top surface would be used to collimate the light from multi-colored LEDs with low color separation or color fringes. The analysis of color enhancement and collimation features of the multi-colored LEDs with different periodic microstructure on the top surface of the TIR lens is presented.