Rod lenses (light guide rods)

OEM Optics

Rod Lenses

Rod lenses are optical components typically used to increase the uniformity of a light source. Light guides are also called homogenizing rods, light guides, homogenizers, or light funnels.

Similar to optical fibers, light guide homogenizing rods use total internal reflection (TIR) to transmit light from the input to the output of the light guide. The refractive index of the substrate is the only factor that affects the critical angle of the light guide, which defines the acceptance angle.

Because light rays enter a light guide at different angles of incidence, the number of reflections within the light guide varies from ray to ray. The smallest angle of incidence, equal to θc, exhibits more reflections than light entering at an angle of incidence many times greater than θc.