Inkjet-Printed GRIN Microlenses on CMOS Imager Wafers for Synthetic Apertures

After defining the application requirements, light-field modeling and simulation tools will be used to develop candidate compact synthetic apertures sensor designs, enabled by CMOS imagers with integrated microlenses. Additive manufacturing will be used to fabricate a series of microlens arrays, that vary in shape (e.g., round, square, hexagonal), pitch (e.g., 0.25-mm, 0.5-mm, 1-mm, etc.) and format (2x2, 4x4, 10x10, 40x40, 240x240, etc.) on glass and silicon substrates. Uniform, anamorphic, and chirped microlens arrays will be fabricated and characterized. Two types of microlenses will be additive-manufactured: 1) homogeneous-composition spherical microlenses; and 2) freeform gradient-index microlenses. The ability to planarize CMOS image sensor wafers and to fabricate highly planar tuned-index spacer layers will also be demonstrated. A working functional imager will be demonstrated that integrates the custom lenslet arrays. In Phase II, the process will be optimized and printed sub-aperture image sensors will be designed that are optimized for configuration in a compact synthetic aperture array. A prototype synthetic aperture imaging system will be fabricated and demonstrated using commercial software.