Freeform illumination design model for multiple light sources simultaneously.

In this paper, we have proposed an innovative model of freeform illumination design, which differs from the current model that covers almost all of the existing freeform illumination systems. In our model, a freeform illumination system is designed for multiple light sources simultaneously, rather than just for one certain source like the current model. All the sources have the same size, shape, intensity distribution, and other photometric characteristics, but are located at different positions or directions. Each source can individually achieve an illumination pattern on the target plane. All the patterns are expected to have the same size, shape, and illuminance distribution, but the position of each pattern has a linear relationship with the position or direction of the corresponding source. Two new (to our knowledge) illumination functions can be realized in our model, as the light sources are non-single and movable. The first one is the continuous scanning of the illumination pattern on the target plane, and the second one achieves a flexible, diverse, and controllable array of illumination patterns on the target plane. As an example, a coaxial freeform illumination system has been designed under the framework of this model, in which multiple collimated light sources are introduced simultaneously. The design method and process of the system are presented. The system is further promoted, and the two new illumination functions are explained in detail based on the design example.