Optical Element Deformation With Spring-Mediated Actuator Coupling

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Solution Overview

Problem

Mounting and maintaining optical elements with a large aspect ratio, such as mirrors or gratings, is challenging due to their low flexural rigidity, which leads to deformation from forces and mechanical stresses during manufacturing, mounting, gravity, and thermal effects, necessitating improved force transmission and actuator replacement mechanisms.

Innovation Solution

A device comprising a spring element, actuator, and coupling element where the actuator is not rigidly connected to the spring element, allowing force transmission via a coupling element to the optical element, enabling easy actuator replacement and decoupling of lateral forces, with a preload mechanism to adjust force direction and transmission ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the actuator is rigidly connected to the optical element, then the force transmission is direct and stable, but the actuator replacement becomes difficult and lateral forces cause unwanted deformations

Engineering Contradiction:
Improveforce transmission stabilityVSAvoidactuator replacement ease
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The rigid connection between actuator and optical element is divided into two separate connections: actuator to spring element, and spring element to optical element. This segmentation allows the actuator to be replaced independently while maintaining stable force transmission through the spring element connection to the optical element.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring element serves as an intermediary component between the actuator and the optical element. It mediates the force transmission, providing both mechanical coupling for stability and decoupling for easy replacement, while also filtering lateral forces through its elastic properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If the actuator is rigidly connected to the optical element, then the force transmission is direct, but lateral forces cause unwanted deformations of the optical element

Engineering Contradiction:
Improveactuating force transmissionVSAvoidlateral force deformations
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The spring element acts as a mediator that transmits the actuating force from the actuator to the optical element while filtering out lateral forces. The elastic properties of the spring element allow it to absorb and dampen lateral force components, preventing them from causing unwanted deformations of the optical element.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The spring constant of the spring element is specifically designed to allow transmission of vertical actuating forces while resisting lateral force transmission. By adjusting the spring constant parameter, the system optimizes force transmission in the desired direction while minimizing harmful lateral force effects on the optical element.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple actuators are used to correct optical surface deformation, then the correction precision is improved, but the complexity of the device increases

Engineering Contradiction:
Improvesurface correction precisionVSAvoidactuator array complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system divides the correction function into multiple independent actuator units, each capable of being replaced individually. This segmentation allows for high precision correction through multiple actuators while simplifying maintenance, as each actuator can be replaced independently without affecting the others, thereby managing device complexity.

Inventive Principle:
Principle #1Segmentation

4Shape

If the actuator stroke is large, then the deformation range of the optical element is increased, but the precision of small deformations is reduced

Engineering Contradiction:
Improveoptical element deformation rangeVSAvoidsmall deformation precision
Core Design Contradiction:
ShapeVSMeasurement precision

Solution Approach 1:

The spring constant of the spring element is optimized to provide appropriate mechanical advantage, transforming the actuator stroke into precise optical element deformations. This parameter optimization allows the system to achieve both large deformation range and high precision by tuning the spring element's mechanical properties.

Inventive Principle:
Principle #35Parameter changes

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

Facilitates easy actuator replacement, reduces unwanted deformations, and enhances long-term stability and precision in optical element deformation, particularly suitable for active and adaptive optics applications.

Implementation Method 1

The force application point and the connection point are advantageously connected to one another by a part of the spring element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3214479B1Apparatus for deforming an optical element and optical element comprising said apparatus
Publication Date: 2025.09.17 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3214479B1 patent drawingFigure 1~2
  • EP3214479B1 patent drawingFigure 3~4
  • EP3214479B1 patent drawingFigure 5~6

AI summary

A device for deforming an optical element (1) is described, comprising a spring element (3) and an actuator (4), wherein the actuator (4) is not rigidly connected to the spring element (4) and is configured to exert an actuating force on at least one point of force application (5) of the spring element (3). The device further comprises a coupling element (2) which is rigidly connected to the spring element (3) at at least one connection point (6) and is configured to transmit the actuating force exerted by the actuator (4) on the spring element (3) to at least one point of the optical element (1). An optical element (1) is also specified in conjunction with the device.