Micro lens array (MLA) is an optical element used in various purposes. For MLA industrial lighting device, such as uniform illumination diffuser or super wide-angle diffuser, it is required to achieve high quality illumination control. When we process MLA mold by ordinary diamond milling, error factors including tool wear, cause the same distribution of shape errors in each micro lens. The MLA lighting device produced using this mold will have an illuminance irregularity on the light distribution corresponding to the shape error distribution. In this study, we have investigated a processing method to vary the distribution of the shape error of each micro lens comprising the MLA for improve illumination quality. This method can be applied to various MLA design, for example, MLA consisting of aspheric micro lens with a maximum tangent angle of more than 60° or non-rotationally symmetric micro lens such as polynomial freeform surface.
|