Miniature Lens Assembly with Movable Element for Active Alignment
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Solution Overview
Problem
The manufacturing of miniature lens assemblies for cameras and projectors faces challenges in aligning tiny lenses accurately, leading to reduced image quality and increased yield loss due to alignment errors, especially as the number of lenses increases and lens assemblies become smaller, with existing passive alignment methods being inadequate and active alignment being too costly for high-volume production.
Innovation Solution
A lens assembly design that includes a movable lens with one or more degrees of freedom to allow for active alignment, compensating for alignment errors and imperfections, while other lenses are passively aligned and mechanically constrained, using a 'rattle' space for the movable lens to adjust its position and secure it with epoxy or adhesive after alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If passive alignment methods are used to align lenses, then manufacturing cost is reduced, but alignment precision deteriorates leading to increased yield loss
Solution Approach 1:
The lens assembly is divided into two groups: passively aligned lenses (fixed in position) and actively aligned lenses (movable with adjustment capability). This segmentation allows different alignment methods to be applied to different parts of the system, optimizing both cost and precision.
Solution Approach 2:
The invention introduces movable lenses with adjustment mechanisms that allow dynamic positioning during assembly. These lenses can be actively aligned to compensate for errors in the passively aligned lenses, transforming a static alignment system into a dynamic one that can correct misalignments.
2Reliability
If the number of lenses in the assembly is increased to improve image quality, then optical performance is improved, but alignment errors are magnified leading to increased yield loss
Solution Approach 1:
The movable lenses act as feedback mechanisms that detect and compensate for alignment errors accumulated from multiple passively aligned lenses. By allowing adjustment of specific lenses, the system can sense misalignments and correct them, maintaining image quality even as the number of lenses increases.
3Volume of moving object
If lens assemblies are made smaller to reduce device size, then compactness is improved, but alignment sensitivity increases leading to higher rejection rates
Solution Approach 1:
In smaller lens assemblies, certain lenses are made movable to provide dynamic alignment compensation. This allows the compact design to maintain alignment tolerance by enabling active adjustment of critical lenses, reducing rejection rates despite increased sensitivity from miniaturization.
Data Source
AI summary
A lens assembly includes at least a pair of lenses fixed in a lens barrel and an additional lens initially having at least one degree of freedom of movement with respect to the other lenses. The additional lens can be fixed in a desired alignment position with respect to the other lenses.