Grayscale projection design method based on micro lens array

Due to its thinness and large focal depth range, micro lens array (MLA) based projectors possess high potential in automotive lighting, traffic signs, and short-distance projection. Recently, researchers have paid extensive attention to projectors that employ micro lens arrays as projection lenses and transmissive chromium layers as masks. In order to expand the application scope of such projectors, we have developed a projection device capable of projecting grayscale images. By specially designing the mask pattern for each micro lens, the projected image from each sub-aperture is different, resulting in varying illuminance levels in different parts of the overlaid image on the image plane. This design method enables the projector to project fine grayscale images without requiring high-precision lithography equipment.