Optical design of a single freeform lens for both counter-beam and pro-beam in LED tunnel lighting

A luminaire designed for tunnel lighting is proposed, featuring the ability to adjust the ratio between counter-beam and pro-beam lighting based on different contexts. This allows the luminaire to achieve the optimal lighting mode for the conditions within the tunnel at that time. When both side LEDs are activated, it operates in symmetric lighting mode. When a single-side LED is activated, it switches to either counter-beam or pro-beam lighting mode. The advantage of this luminaire lies in the use of a single freeform secondary lens and LEDs, making installation simpler. It ensures driver safety and is more energy-efficient than traditional tunnel lights.