Design optimization of large-size format edge-lit light guide units

In this paper, we present an original method of dot-pattern generation dedicated to design optimization of large-size format ELBUs (Edge-Lit Light Guide Unit), where the number of dots greatly exceeds the maximum allowable number of optical objects supported by most common ray-tracing software. In the proposed method, in order to simplify the computational problem, an original optical system is replaced by an equivalent one. Accordingly, the original dot pattern is splitted into multiple small sections. Then, these sections are replaced by equivalent cells with continuous diffusing film. After that, we adjust the TIS (Total Integrated Scatter) two-dimensional distribution over the grid of equivalent cells, using an iterative optimization procedure. Finally, the obtained optimal TIS distribution is converted into the dot size distribution by applying an appropriate conversion rule. An original semi-empirical equation dedicated to rectangular large-size LGPs (Light Guide Plate) is proposed for the initial guess of the TIS distribution. It allows significantly reducing the time needed to dot pattern optimization.