關鍵字 : LEDs，二階光學設計，車後燈，導光條，擴散片。 ;In this thesis, we provide a secondary optical design of cavity light guide with LEDs, and apply to a line-structured vehicle tail lamp which is uniform on the light-emitting surface and stereoscopic. The analysis includes the light leakage issue with different light guide structures and the unifomity depending on the transmittance of the diffuser. Finally, this optical design is utilized in the tail lamp of bicycle to meet the K-mark regulation of Germany.
