Deformable Mirror With Segmented Stiffness and Magnetic Actuators
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Solution Overview
Problem
Deformable mirrors with force actuators face challenges in distributing stiffness effectively, leading to low resonance frequency and complexity in construction, as well as issues with thermal expansion and repairability.
Innovation Solution
A two-stage structure incorporating force actuators with rigid and flexible link means, where mini secondary membranes are created to distribute stiffness and transmit deformation to the reflective membrane, while keeping elements away from the membrane to prevent dust accumulation and thermal issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the membrane is suspended over the edges to reduce complexity, then the construction is simpler, but the stiffness is low and resonance frequency decreases
Solution Approach 1:
The support structure is segmented into multiple discrete support points distributed across the membrane背面, rather than continuous edge support. This segmentation allows localized stiffness enhancement while maintaining overall structural simplicity and reducing the number of complex boundary conditions.
Solution Approach 2:
Stiffness is not uniformly distributed but locally enhanced at specific support points where actuators are positioned. The membrane has varying stiffness characteristics: high stiffness at support points for actuator effectiveness, and lower stiffness in between for deformability. This local quality differentiation resolves the contradiction between overall stiffness and construction simplicity.
2Area of stationary object
If the membrane diameter is increased to improve performance, then the mirror performance improves, but the resonance frequency decreases due to low stiffness
Solution Approach 1:
By implementing localized stiffness enhancement at distributed support points across the membrane, larger diameter membranes can maintain high resonance frequencies. The local stiffness at support points counteracts the natural frequency reduction that would otherwise occur with increased membrane area, enabling large mirrors with high-speed response.
Solution Approach 2:
The support structure provides dynamic stiffness through the actuator-membrane interaction. The actuators can actively adjust the local stiffness and tension at support points, allowing the membrane to maintain optimal dynamic characteristics across a range of operating conditions and frequencies, even at large diameters.
3Measurement precision
If force actuators are placed close to the membrane to improve control, then the control precision improves, but thermal expansion and dust accumulation become problems
Solution Approach 1:
A magnetic field is introduced as an intermediary between the actuator and the membrane. The actuator generates a magnetic field that interacts with a magnetized layer on the membrane背面, transmitting force without physical contact. This intermediary field allows precise control while maintaining spatial separation, thereby eliminating thermal expansion issues and dust accumulation problems associated with close physical placement.
4Speed
If the stiffness of the membrane is increased to improve frequency response, then the resonance frequency increases, but the capacity for deformation is reduced
Solution Approach 1:
The membrane exhibits spatially varying stiffness: high local stiffness at support points for frequency response, and lower stiffness in deformable zones for shape control capacity. This local quality differentiation allows the membrane to simultaneously achieve high resonance frequencies and sufficient deformation capacity by optimizing stiffness distribution rather than uniform stiffness increase.
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 solution enhances the stiffness distribution and resonance frequency of deformable mirrors, simplifies construction, and allows for easier maintenance and reduced thermal expansion, improving the overall performance and durability of the mirrors.
Implementation Method 1
An actuator made up of an electromagnet and of a permanent magnet is referred to as a 'force actuator' whenever it is control of the generated magnetic force that controls the amplitude of the displacement of the magnet for deforming the membrane
Data Source
AI summary
The present invention relates to a deformable mirror (1) comprising a deformable membrane (2) with a reflective outer face (3) and an opposite face (4), a rigid support plate (7), and at least one force actuator (5, 6). Each actuator (5, 6) comprises at least two elements (5, 6) suitable for interacting with each other remotely so as to generate a force in a direction that is substantially perpendicular to the surface of the initially non-deformed membrane (2), and suitable for being displaced relative to each other in the direction of said generated force so as to cause said membrane (2) to be deformed locally. One of the two elements (5, 6) is incorporated into the support plate (7) and the other element is coupled to the membrane (2). One of said two elements (5, 6) is suitable for controlling the intensity of said generated force. According to the invention, the mirror (1) further comprises reference means (7, 8) coupled to the membrane (2) via at least one rigid link means (10) and via at least one flexible link means (11). Each rigid link means (10) is secured to said membrane (2), and each flexible link means (11) is secured at least in part to the reference means (7, 8).