Compliant Multi-Lenslet Refocusing to Minimize Wavefront Errors
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Solution Overview
Problem
Existing refocusable lens systems introduce undesired optical wavefront errors during the transition between near-focus and far-focus states due to the formation of multiple foci and varying optical powers in constituent lenslets, leading to diffraction-limited performance only at the extremes of the transition.
Innovation Solution
The lens system is configured with multiple pairs of neighboring lenslets, each with aspheric surfaces, and employs bending and radially-directed loads to minimize wavefront errors by altering the degree of applanation between lens surfaces, using structural supports to apply forces along the optical axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the lens system transitions from non-applanated to fully-applanated state to change focal length, then the focal length changes from short to long, but wavefront errors are introduced due to multiple foci formation
Solution Approach 1:
The patent applies different surface curvatures to different regions of the lenslet surfaces. Specifically, the optical portions of the lenslet surfaces have different curvatures than the non-optical portions, creating localized optical zones that maintain consistent focal properties. This local differentiation allows the lens system to transition between focal lengths while minimizing wavefront errors by ensuring that only the optimized optical portions contribute to image formation.
Solution Approach 2:
The lens system is divided into multiple discrete lenslets arranged in an array, with each lenslet having distinct optical and non-optical surface portions. This segmentation allows independent optimization of each lenslet's optical performance while collectively achieving variable focal length capability through controlled applanation of specific lenslet interfaces.
2Adaptability or versatility
If the degree of applanation is increased to achieve longer focal length, then the optical power changes, but multiple foci are formed causing image quality degradation
Solution Approach 1:
By creating localized optical portions on lenslet surfaces with specific curvature characteristics, the patent ensures that light rays are focused consistently regardless of the overall applanation state. The non-optical portions with different curvature do not contribute to image formation, thereby preventing multiple focus formation and maintaining reliable image quality across the full range of optical power variation.
3Adaptability or versatility
If the lens system operates at intermediate applanation states during transition, then continuous focal length adjustment is achieved, but wavefront errors increase reducing diffraction-limited performance
Solution Approach 1:
The patent maintains diffraction-limited performance at all intermediate applanation states by ensuring that the optical portions of lenslet surfaces consistently provide the desired focal properties. The localized optical zones are designed such that their curvature and optical power remain optimal regardless of the overall compression state, while non-optical portions are excluded from the optical path, preventing aberration introduction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces wavefront errors across the focal length transition, improving image quality and maintaining diffraction-limited performance throughout the focus range.
Implementation Method 1
a group of elastically deformable lenslets (e.g., made of silicone or other compliant materials) that are configured to change their focal length by altering the curvature of their surfaces
Implementation Method 2
A re-focusable lens system configured to operate by having its optical power changed as a result of forming and/or altering the applanated (flattened or even flat) surface areas of contact between the surfaces of the individual elastically deformable constituent lenslets
Data Source
AI summary
Methods for reducing wavefront errors, manifesting during the process of refocusing of an accommodating (re-focusable) lens system that includes an elastically-deformable lenslet disposed along an optical axis and that has an optical power that is varied by changing the degree of applanation of an area of contact of such elastically-deformable lenslet with a neighboring lenslet in response to variation of force applied to the lenslet axially (in one case—by an external element connected with or forming a part of the lens system housing and/or lenslet support element). Associated accommodating lens systems.