First prototypes of a new adaptive deformable mirror (DM) are presented. The DM consists of a thin membrane which acts as the correcting element. A grid of low voltage electro-magnetical push-pull actuators, - located in an actuator plate -, impose out-of-plane displacements in the mirror’s membrane. To provide a stable and stiff reference plane for the actuators, a mechanically stable and thermally decoupled honeycomb support structure is added.One of the key elements in the design is the actuator grid. Each actuator consists of a closed magnetic circuit in which a strong permanent magnet (PM) attracts a magnetic permeable membrane. By applying a current through the coil which is situated around this magnet, this magnetic force can be influenced. Both the PM and the coil are connected to the fixed world and only the magnetic membrane’s deflection will increase or decrease. The movement of each membrane is in a piston-free manner transferred to the reflective mirror surface. The design allows for a long total stroke and inter actuator stroke. The actuators can be produced in arrays which make the design extendable.Besides the presented prototype, this paper describes how relevant properties of the actuator, such as stiffness and efficiency, can be controlled. In a test-setup the actuators are tested and relevant parameters are measured. The power dissipation in the actuator grid is in the order of milliwatts per actuator. Because of this low power dissipation active cooling is not required.
|Title of host publication
|SPIE Optics & Photonics 2005; Advanced Wavefront Control: Methods, Devices, and Applications III
|Place of Publication
|United States, San Diego
|Published - 2005