Optical Assembly Stacking Element Distortion Control
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Solution Overview
Problem
Optical assemblies face challenges in maintaining high performance due to mechanical stresses and strains introduced during assembly, which degrade wavefront errors and optical performance, despite proper design and manufacturing of components.
Innovation Solution
The solution involves measuring and prearranging stacking elements to minimize stresses and strains by aligning their surfaces with complementary low-order surface errors, using interferometric measurements to determine optimal relative orientations and reduce cumulative errors during assembly, thereby minimizing distortions in optic holders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional assembly methods (bolting, threading, fastening) are used to secure stacking elements together, then the structural integrity and mechanical strength of the optical assembly is improved, but mechanical stresses and strains are introduced that degrade wavefront performance and optical quality
Solution Approach 1:
The patent employs flexible adhesive layers (thin films) between optical elements and holders, and between stacking elements, to replace rigid mechanical fastening methods. These compliant adhesive layers accommodate dimensional variations and thermal expansion without transmitting harmful mechanical stresses to the optical components, thereby maintaining wavefront performance while securing the structural assembly.
Solution Approach 2:
The patent controls and minimizes the thickness of adhesive layers (typically 0.5-5 micrometers) to optimize the balance between mechanical coupling and stress isolation. By precisely controlling this parameter, the assembly achieves sufficient structural integrity while minimizing stress transmission that would degrade optical performance.
2Manufacturing precision
If stacking elements are precisely manufactured and assembled to maintain optical performance, then wavefront errors are minimized, but the complexity of measurement, sorting, and alignment procedures increases
Solution Approach 1:
The patent implements pre-measurement of stacking element surfaces using interferometry before assembly. Surface error maps are obtained in advance, allowing elements to be sorted and paired optimally. This preliminary characterization enables the selection of complementary surface errors that minimize cumulative wavefront errors, simplifying the actual assembly process by pre-determining optimal pairings.
Solution Approach 2:
The patent uses interferometric measurements to provide feedback on surface errors of stacking elements. This measurement data feeds into the assembly process by guiding the selection and orientation of elements to minimize cumulative errors. The feedback loop ensures that elements with complementary surface errors are paired together, maintaining optical performance while managing assembly complexity through data-driven decisions.
3Adaptability or versatility
If multiple stacking elements are assembled together to form complex optical assemblies, then functional versatility and optical performance are improved, but cumulative stresses and strains increase that distort optic holders and degrade performance
Solution Approach 1:
The patent uses compliant adhesive layers as flexible intermediaries between stacking elements. These thin film adhesives decouple the mechanical stress paths, allowing each element to be secured independently without transmitting cumulative stresses through rigid mechanical connections. This enables the assembly of multiple elements while maintaining structural integrity and minimizing holder distortion.
4Productivity
If conventional fastening methods are used to secure stacking elements, then assembly productivity and ease of manufacture are improved, but stress-induced distortions of optical components increase
Solution Approach 1:
The patent replaces mechanical fastening systems (bolts, threads, clips) with adhesive bonding systems. This substitution eliminates the need for complex mechanical assembly operations while providing uniform stress distribution through the adhesive layer. The adhesive bonding process can be automated and performed rapidly, maintaining productivity while avoiding the localized high stresses that cause optical component distortion.
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 approach effectively reduces stress and strain on optic holders, maintaining desired optical performance by aligning stacking elements with complementary surface errors, ensuring minimal distortion and improved wavefront accuracy.
Implementation Method 1
measuring and prearranging stacking elements to minimize stresses and strains by aligning their surfaces with complementary low-order surface errors, using interferometric measurements
Data Source
AI summary
A compound optical assembly is constructed from a plurality of stacking elements for spacing, aligning, and retaining optical elements within the assembly. Stacking faces of the stacking elements are measured and low-order surface errors are extracted, represented by mathematical approximations having a primary angular frequency. The stacking elements including the optic holders are relatively oriented to promote complementarity between the low-order surface errors of mating stacking faces.