Optical element stack assemblies

Abstract

Optical stack assemblies and fabrication techniques thereof. The optical stack assembly includes first and second sub-assemblies, each of which include a substrate and a sub-structure fixed to the respective substrate. Each sub-structures includes a respective first edge feature and a respective second edge feature that project away from the substrate of that sub-structure, each second edge feature being disposed laterally closer to an outer periphery of the respective sub-structure than the first edge feature of the same sub-structure. The first edge feature of the first sub-structure is in direct contact with the first edge feature of the second sub¬structure, while the second edge feature of the first sub-structure and the second edge feature of the second sub-structure are attached to one another by adhesive. At least one of the first or second sub-structures includes an optical element on a same side of the sub-structure as the first and second edge features of that sub-structure. The optical element stack assembly further includes a spacer laterally surrounding, and moulded to, the first and second sub-assemblies.