Deformable Mirror Protrusions for Thermal Expansion Control

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Solution Overview

Problem

Existing controllably deformable mirrors suffer from undesired deformations due to the attachment of moving parts, which can lead to uncontrolled detrimental effects on wave front adjustments, particularly due to thermal expansion and misalignment.

Innovation Solution

The use of protrusions made of the same material as the flexible layer, or with substantially the same thermal expansion coefficient, between the back surface of the flexible layer and the moving part of the actuator, reduces the distortion effect of thermal expansion and facilitates assembly by self-alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If moving parts are attached to the flexible layer using adhesive or bonding methods, then the actuators can effectively deform the mirror surface, but local deformations and thermal expansion effects occur that degrade wave front quality

Engineering Contradiction:

Improvewave front adjustment qualityVSAvoidlocal deformation and thermal expansion

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

A protrusion made of material with matched thermal expansion properties is introduced as an intermediary between the moving part and the flexible layer. This protrusion acts as a mediator that transmits actuator forces while isolating the flexible layer from thermal expansion effects and localized stress concentrations that would otherwise degrade wave front quality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protrusion is made of material with substantially the same thermal expansion coefficient as the flexible layer, creating thermal homogeneity at the interface. This ensures that temperature changes do not generate differential expansion or contraction forces that would cause local deformations of the mirror surface.

Inventive Principle:

Principle #33Homogeneity

2Ease of manufacture

If moving parts are directly bonded to the flexible layer, then assembly is simplified, but misalignment and attachment-induced deformations occur

Engineering Contradiction:

Improveassembly simplicityVSAvoidattachment alignment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The protrusion serves as a positioning intermediary that provides a well-defined mechanical interface between the moving part and the flexible layer. Its geometry and material properties facilitate precise alignment during assembly while distributing attachment forces over a larger area, reducing misalignment-induced deformations.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If actuators are used to deform the mirror surface, then wave front phase patterns can be adjusted, but attachment points create regions of reduced flexibility with higher spatial frequency deformations

Engineering Contradiction:

Improvewave front adjustment capabilityVSAvoidmirror surface flexibility

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The protrusion acts as a force transmission intermediary that decouples the actuator attachment point from the flexible layer. This allows actuators to apply forces without creating localized stiffness variations or high spatial frequency deformations on the mirror surface, preserving the flexibility and smoothness of the wave front adjustments.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 significantly reduces local distortions and thermal expansion effects on the flexible layer, improving the quality of wave front adjustments by minimizing unwanted deformations and ensuring precise control over the mirror's deformation.

Implementation Method 1

the use of protrusions made of the same material as the flexible layer, or with substantially the same thermal expansion coefficient, between the back surface of the flexible layer and the moving part of the actuator, reduces the distortion effect of thermal expansion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12242050B2Controllably deformable mirror device

Publication Date: 2025.03.04 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO

AI summary

A deformable mirror device has a flexible layer with a front surface that forms a mirror surface or to which a mirror layer forming mirror surface is attached. The flexible layer consists homogeneously of a first material. Protrusions extend from the back surface of the flexible layer. The protrusions consist homogeneously of the first material or a material with substantially the same thermal expansion coefficient. A plurality actuators are coupled to the protrusions and via the protrusions to the flexible layer, to deform the flexible layer. The flexible layer and the protrusions may be part of an integral body of the first material, or bonded to the flexible layer. The distal end of each protrusion has a curved surface that at least partly has a spherical shape.