Microlens array expander with an improved light intensity distribution throughperiodic submicro-scale filling for near-eye displays.

ABSTRACT

A type of microlens array (MLA) expander with an improved light intensity distribution (LID) is designed and fabricated through submicro-scale filling, which could be applied to near-eye displays. Through the reflection of a 0.8-µm-wide metal filling, the light field is split and superimposed only through the microlens. The bright spot at the center of the LID is effectively eliminated. The results demonstrate that the expanded numerical aperture (NA) and focal length are about 0.38 and 19 µm, respectively, and the error in the radius of curvature is within 5% between the experimental and designed values. An improved image quality with an 80% brightness uniformity for an area of 22×22 mm2 is realized through the MLA. Compared with the MLA based on thermal reflow, the largest NA is obtained with the smallest focal length and gap. The experimental LID is consistent with that obtained by a theoretical simulation.