Membrane-Suspended Optical Elements for Wafer-Scale Alignment
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Solution Overview
Problem
Current methods for fabricating wafer-scale miniature camera systems face challenges in accurately positioning and layering optical elements, leading to misalignment and inefficiencies in the formation of complex optical structures.
Innovation Solution
The use of a structured substrate with membrane-suspended optical elements, where each optical element is formed within apertures and supported by a membrane, allowing for precise alignment and layering through a multi-step process using fabrication pedestals that shape and harden optical materials, reducing the need for spacer wafers and enabling adjustable positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical elements are formed directly on a substrate using precision-machined fabrication masters, then manufacturing precision can be achieved, but device complexity increases due to the need for multiple fabrication masters and sequential layering processes
Solution Approach 1:
The optical element is segmented into a suspended optical element portion and a membrane portion, with the membrane serving as both structural support and alignment reference. This segmentation allows the optical element to be formed in a single step without requiring sequential layering of multiple fabrication masters.
Solution Approach 2:
The membrane serves multiple functions: it suspends the optical element, provides mechanical support, and acts as an alignment reference feature for subsequent processing steps. This multi-functionality eliminates the need for separate alignment structures and reduces the number of fabrication masters required.
2Device complexity
If multiple fabrication masters are used sequentially to form layered optical elements, then complex optical structures can be created, but productivity decreases due to the time-consuming sequential process
Solution Approach 1:
The membrane is pre-formed on the substrate with integrated alignment features before the optical element is deposited. This preliminary action establishes the alignment reference in advance, eliminating the need for sequential alignment operations with multiple fabrication masters and significantly reducing fabrication time.
Solution Approach 2:
The fabrication process merges the formation of the membrane, the optical element, and the alignment features into a single integrated process step. This combining of operations that would traditionally require multiple sequential steps dramatically improves productivity while maintaining the ability to create complex optical structures.
3Device complexity
If traditional substrate mounting is used without membrane suspension, then structural simplicity is maintained, but alignment accuracy deteriorates due to the need for additional spacer wafers and coverglass
Solution Approach 1:
A thin membrane film is used to suspend the optical element above the substrate. This membrane provides a stable, flat reference plane for precise alignment while eliminating the need for thick spacer wafers and coverglass. The membrane's flexibility allows for precise positioning control, and its thin profile maintains structural simplicity.
Data Source
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AI summary
Membrane suspended optical elements include a structured substrate including a plurality of apertmes defined therein and an array of optical elements, each of the optical elements being suspended by membiane within one of the apertures.