Lens With Offset Optical Axis And Multiple Seating Surfaces
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Solution Overview
Problem
Existing optical devices face alignment issues due to component height variations, requiring large inventories of lenses ground to specific heights for precise optical alignment, which is inefficient and temperature-dependent.
Innovation Solution
A lens with two or more seating surfaces and an offset optical axis, allowing for orientation to provide multiple optical axis heights, eliminating the need for separate bins of lenses and enabling compensation for glue thickness and optical path height variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple bins of lenses ground to particular heights are used to achieve precise optical alignment, then optical alignment precision is improved, but device complexity and inventory requirements increase
Solution Approach 1:
The lens is designed with multiple seating surfaces (at least two, typically four) that allow the same lens to be positioned at different heights by selecting different seating surfaces. The optical axis is offset from the center of the lens, enabling each seating surface to provide a different optical axis height. This multi-functional design eliminates the need for multiple bins of lenses with different ground heights, as a single lens can satisfy multiple optical height requirements.
Solution Approach 2:
The lens is segmented into multiple seating surfaces, each providing a different reference plane for positioning. By dividing the bottom surface of the lens into multiple discrete seating surfaces at different heights, the lens can be oriented to provide precise optical alignment for different optical paths without requiring separate lenses for each height requirement.
2Measurement precision
If glue thickness is varied to adjust lens height for optical alignment, then optical alignment is improved, but temperature stability deteriorates due to higher CTE of glue
Solution Approach 1:
The required height adjustment is performed in advance during lens manufacturing by providing multiple seating surfaces at predetermined heights, rather than adjusting glue thickness during assembly. This preliminary structuring of height variations eliminates the need to rely on glue thickness variations, thereby avoiding the temperature dependence introduced by the glue's higher CTE.
3Device complexity
If a single lens with offset optical axis and multiple seating surfaces is used, then inventory requirements are reduced, but manufacturing precision requirements increase
Solution Approach 1:
Different regions of the lens bottom surface are given different local properties through the creation of multiple seating surfaces at different heights. Each seating surface is precisely formed with the required flatness and orientation, while the optical axis is deliberately offset from the lens center to enable the height variation. This localized differentiation of surface properties allows a single lens to provide multiple precise optical heights.
Data Source
AI summary
The invention relates to a lens comprising two or more seating surfaces and an optical axis offset from the center of the lens such that the optical axis is spaced by a first distance from a first seating surface and by a second distance from a second seating surface. The first and second distances are different so that the lens can be orientated to provide at least two different optical axis heights depending upon which seating surface is chosen to seat the lens.