Optical Element Support Structure with Radial Thickness for Stress Relief
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Solution Overview
Problem
Existing optical elements, such as lens assemblies, face challenges in achieving impact resistance while maintaining good optical and mechanical properties, particularly in designs with adjustable focal length and complex movable parts.
Innovation Solution
An optical element with a bendable cover member and supporting structure, featuring a gradual or stepped increase in thickness and Young's modulus, is designed to mitigate stress singularities, allowing for improved impact resistance without compromising optical and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the supporting structure has abrupt changes in thickness or Young's modulus at the interface with the bendable cover member, then the manufacturing is simpler, but stress singularities occur leading to poor impact resistance
Solution Approach 1:
The supporting structure implements local quality by having different thickness values at different radial positions. Specifically, the thickness increases from the optical axis toward the periphery, creating a gradient that locally distributes stress more evenly. This prevents stress singularities at abrupt interfaces while maintaining manufacturing feasibility through controlled thickness variation.
Solution Approach 2:
The patent applies parameter changes by varying the thickness parameter of the supporting structure as a function of radial distance from the optical axis. This continuous or stepped change in thickness parameter creates a gradual transition in mechanical properties, eliminating abrupt stress concentrations while remaining manufacturable.
2Strength
If the supporting structure is made thicker to improve impact resistance, then the strength increases, but the optical properties and mechanical flexibility deteriorate
Solution Approach 1:
The supporting structure implements local quality by having different thickness values at different radial positions. Specifically, the thickness increases from the optical axis toward the periphery, creating a gradient that locally distributes stress more evenly. This prevents stress singularities at abrupt interfaces while maintaining manufacturing feasibility through controlled thickness variation.
Solution Approach 2:
The patent introduces a radial dimension to the thickness variation, transitioning from uniform thickness to radially dependent thickness. This dimensional change allows the structure to be thin near the optical axis (preserving optical quality) and thicker at the periphery (providing impact resistance), thus resolving the contradiction between strength and optical properties.
3Ease of manufacture
If the supporting structure has uniform thickness, then the manufacturing is simpler, but stress concentrations occur at the interface edges leading to reduced durability
Solution Approach 1:
The supporting structure implements local quality by having different thickness values at different radial positions. Specifically, the thickness increases from the optical axis toward the periphery, creating a gradient that locally distributes stress more evenly. This prevents stress singularities at abrupt interfaces while maintaining manufacturing feasibility through controlled thickness variation.
Solution Approach 2:
The patent employs curvature by creating a radially symmetric thickness distribution that is thicker at the periphery and thinner near the optical axis. This curved, non-uniform thickness profile smoothly transitions the structural properties, eliminating abrupt stress concentrations at interfaces while remaining manufacturable.
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
The solution provides enhanced impact resistance and maintains optical quality, enabling the optical element to endure significant accelerations and decelerations without significant degradation in focal length adjustment capabilities.
Implementation Method 1
one or more actuators, such as one or more piezoelectric actuators, arranged for shaping said bendable cover member into a desired shape
Data Source
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AI summary
There is presented an optical element 100, such as a tuneable lens, wherein there is provided means 128 to mitigate problems with stress concentration in a bendable cover member 102 at a border of a supporting structure 101, which in the absence of said means would entail a stress singularity issue due to an abrupt change in mechanical properties around the bendable cover member 102.