Deformable Mirror Actuator Shape Correction

Solution Overview

Problem

The conventional grinding and polishing techniques for fabricating aspheric mirrors are time-consuming and expensive due to the need for small tools that match the varying curvature of the mirror surface, limiting the efficiency and cost-effectiveness of large mirror production for telescopes.

Innovation Solution

Deforming a thin spherical meniscus mirror using actuators to achieve an off-axis aspheric shape with fewer actuator-to-mirror interface points, potentially avoiding the need for polishing and expensive tooling, and allowing for the creation of lightweight, low-cost mirror segments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional grinding and polishing techniques are used to fabricate aspheric mirrors, then manufacturing precision can be achieved, but production time and cost increase significantly

Engineering Contradiction:

Improvemirror shape accuracyVSAvoidfabrication time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by first fabricating a spherical mirror using conventional efficient techniques, then using computational methods to calculate and apply corrective deformations. This pre-computation of the deformation required to achieve the aspheric shape from a spherical base allows for rapid transformation without time-consuming conventional aspheric grinding and polishing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical grinding and polishing process with a computational deformation approach. Instead of mechanically removing material to achieve the aspheric shape, the system uses calculated deformation fields to transform the spherical mirror into the required aspheric configuration, substituting mechanical fabrication with computational design.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If conventional grinding and polishing techniques are used to fabricate aspheric mirrors, then manufacturing precision can be achieved, but fabrication cost increases

Engineering Contradiction:

Improvemirror shape accuracyVSAvoidfabrication cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by first fabricating a spherical mirror using conventional efficient techniques, then using computational methods to calculate and apply corrective deformations. This pre-computation of the deformation required to achieve the aspheric shape from a spherical base allows for rapid transformation without time-consuming conventional aspheric grinding and polishing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical grinding and polishing process with a computational deformation approach. Instead of mechanically removing material to achieve the aspheric shape, the system uses calculated deformation fields to transform the spherical mirror into the required aspheric configuration, substituting mechanical fabrication with computational design.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If a large tool is used for grinding and polishing spherical mirrors, then productivity increases, but the tool cannot match the varying curvature of aspheric mirror surfaces

Engineering Contradiction:

Improvematerial removal rateVSAvoidsurface contour matching

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the mirror fabrication process into two distinct stages: first fabricating a spherical mirror using a large tool for high productivity, then applying localized deformations through computational methods to achieve the aspheric shape. This segmentation allows each stage to optimize for its specific requirements without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by first fabricating a spherical mirror using conventional efficient techniques, then using computational methods to calculate and apply corrective deformations. This pre-computation of the deformation required to achieve the aspheric shape from a spherical base allows for rapid transformation without time-consuming conventional aspheric grinding and polishing.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP2781940B1High correctabillity deformable mirror

Publication Date: 2018.07.25 GOODRICH CORP

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AI summary

A telescope, mirror assembly and method of forming an aspheric mirror is disclosed. The telescope includes the mirror assembly which has a substantially spherical surface contour in a relaxed state. A plurality of actuators (300) distributed substantially along an outer edge (204) of the mirror (200) is configured to apply a load to the mirror assembly to deform the mirror (200) to obtain a substantially aspheric surface contour.