Solid state light tube with periodic units of lateral-emitting LEDs

In this paper, the design and analysis of a novel solid state light tube is presented. The tube is constructed with periodic units of lateral-emitting LEDs. In each unit, two LEDs are mounted on two metal plates, respectively, which are installed at the two ends of a light guide, facing inward to each other. The light emitted from the LEDs firstly transmits in the light guide and then gets outside after reflection and refraction. This light tube structure can provide a more uniform optical field distribution and eliminate the “spotty effect” of commercial LED light tubes. In order to optimize the design, different dimensions of the light guide were studied. A prototype of LED desk lamp using the developed light tube was manufactured. The illumination performance of the lamp was investigated. In addition, an analytical model was developed to facilitate the design of the light guide. Analytical modeling results and experimental data showed reasonable agreement.