Bipod Flexure Mounts for Wavefront Error Reduction

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Solution Overview

Problem

Reflective optics are sensitive to deformations caused by interface imperfections between structures, leading to increased wavefront error due to mounting imperfections between optics and their bases or other components.

Innovation Solution

The use of bipod flexure mounts, which are designed to secure optical elements like mirrors to a base while isolating them from localized moment strain, formed by chemical etching and tangentially bonded at equally spaced locations, providing a slender aspect ratio and multiple spokes for low torsional and linear stiffness, thereby minimizing distortion and maintaining reflection characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If traditional rigid mounting methods are used to secure optics to base, then structural stability is improved, but interface imperfections cause optic deformations and increase wavefront error

Engineering Contradiction:

Improvestructural stabilityVSAvoidwavefront error

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent employs a thin-film flexible mount structure that can elastically deform to accommodate interface imperfections between the optic and base, preventing stress concentration and optic deformation while maintaining structural stability

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent modifies the mechanical parameters of the mounting structure by using flexible materials and designs with specific stiffness characteristics, allowing the mount to adapt to interface variations without transmitting harmful stresses to the optic

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If flexible mount design is used to reduce stress on optics, then wavefront error is reduced, but mounting precision and position accuracy may deteriorate

Engineering Contradiction:

Improvewavefront errorVSAvoidmounting precision

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The flexible mount is segmented into multiple functional zones with different stiffness characteristics, allowing selective flexibility in certain areas while maintaining precision in critical mounting regions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flexible mount acts as an intermediary element between the rigid base and optic, absorbing interface imperfections while maintaining precise optical alignment through its controlled flexibility

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If rigid mounting structure is used to ensure precise positioning, then position accuracy is improved, but localized moment strain distorts the optic and increases wavefront error

Engineering Contradiction:

Improveposition accuracyVSAvoidlocalized moment strain

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The thin-film flexible mount distributes mounting forces over a larger area and prevents localized moment strain by accommodating interface variations through elastic deformation, protecting the optic from distortion

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS11579403B22D bi-pod flexure design, mount technique and process for implementation

Publication Date: 2023.02.14 RAYTHEON CO

AI summary

A bipod flexure mount couples an optic to a base while isolating the optic from strain to resist wavefront error. The bipod flexure mount has a distal attachment pad to be coupled to the optic and a proximal attachment pad to be coupled to the base. A pair of beams extend between and couple the distal and proximal attachment pads. The distal attachment pad, the proximal attachment pad and the pair of beams are disposed in and define a planar layer with opposite planar surfaces that are substantially parallel. The bipod flexure mount is relatively flexible about four degrees of freedom and is relatively stiff about two degrees of freedom.