Deformable Mirror Rigid Plate Decouples Parasitic Torques

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Solution Overview

Problem

Modern telescopes with active deformable optics face integration defects, misalignment, and parasitic torques due to the connection between the mirror and actuators, which affect optical performance and are exacerbated by gravitational and launch-related forces.

Innovation Solution

A deformable mirror design featuring a deformable membrane with a supporting structure, an actuator, and a rigid planar plate decoupling parasitic torques, using elastic elements to absorb forces and moments, and allowing free movement to optimize deformation precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a floating head mounted on springs is used to divide actuator movement, then the resolution is improved, but parasitic torques and misalignment are introduced

Engineering Contradiction:
ImproveresolutionVSAvoidparasitic torques
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

A rigid planar plate is introduced as an intermediary element between the actuator and the deformable membrane. This plate serves as a mediator that transmits only axial forces while blocking parasitic torques and moments from reaching the membrane, thus resolving the contradiction between achieving high resolution through floating heads and eliminating parasitic torques

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If a rigid connection between mirror and actuators is used during launch, then structural stability is improved, but additional forces and moments are generated on the mirror

Engineering Contradiction:
Improvestructural stabilityVSAvoidforces and moments on mirror
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The harmful forces and moments are extracted from the force transmission path by the rigid planar plate. The plate is configured to take up and isolate parasitic forces, moments, and torques generated during launch, preventing them from being transmitted to the deformable membrane while maintaining the rigid connection needed for structural stability

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If actuators are fixed directly to the rear of the mirror, then integration is simplified, but uncorrectable deformations occur

Engineering Contradiction:
Improveintegration complexityVSAvoidmirror deformation precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The connection system is segmented into distinct functional elements: the actuator, the rigid planar plate, and the deformable membrane. This segmentation allows each component to perform its specific function - the actuator provides force, the plate transmits only axial forces and blocks parasitic torques, and the membrane deforms precisely - thereby resolving the contradiction between simple integration and precise deformation control

Inventive Principle:
Principle #1Segmentation

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 effectively reduces parasitic deformations, misalignment, and torque injection, enhancing optical performance and stability under gravitational and launch conditions by decoupling forces and moments, thereby improving the mirror's deformation precision and reducing stress.

Implementation Method 1

an elastic element positioned between the plate and the deformable membrane

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the second end being able to move relative to the first end along a first axis substantially perpendicular to the first plane to exert on the rear face an axial force according to the first axis, so as to locally deform the deformable membrane

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3203299B1Deformable mirror
Publication Date: 2018.11.14 THALES SA
  • EP3203299B1 patent drawingFigure 1~2
  • EP3203299B1 patent drawingFigure 3~4
  • EP3203299B1 patent drawingFigure 5~6

AI summary

The invention relates to a deformable mirror (10) comprising a deformable membrane (11) extending at rest in a first plane (13) and having a reflective front face and a rear face (12) opposite to the front face, a carrier structure (14), an actuator (15) having a first (16) and a second end (17), the first end (16) being fixed on the carrier structure (14), the second end (17) being able to move relative to the first end (16) along a first axis (Z) substantially perpendicular to the first plane (13) to exert on the rear face (12) an axial force along the first axis (Z), so as to locally deform the deformable membrane (11).According to the invention, the mirror comprises a plate (18) substantially flat in a second plane (19) substantially parallel to the first plane (13), positioned between the actuator (15) and the deformable membrane (11), linked to the rear face (12) and capable of deforming when the actuator (15) exerts the axial force, and the plate (18) is rigid in the second plane (19) so as to absorb forces applied to the mirror in the second plane (19).