Design and fabrication of a large-stroke deformable mirror using a gear-shape ionic-conductive polymer metal composite.

Wei HC, Su GD - Sensors (Basel) (2012)

Related In: Results  -  Collection

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f4-sensors-12-11100: The schematic diagram of the geometry parameters of a cantilever beam shaped IPMC and the tip displacement.
Mentions: From the simulation of the FEM by varying the length and width of IPMC and the half thickness of Nafion®, as shown in Figure 3, with surface stress equal to 100 Pa, we could derive the relation of surface stress to tip displacement. According to this Figure, we try to determine the effects of the geometry on the tip displacement. This result leads to Equation (1):(1)sansys∝L2h−1⋅Pwhere Sansys is the simulated max tip displacement, L is the length, h is the half thickness of Nafion®, and P is the surface stress on each element. We also simplified the Nasser's analytical solution [11],(2)Me=˙k0keϕ0ahwfrom the relations:(3)Mk=1ρEI[12](4)andI=wh6(4h2+w2)≅2wh33[12](5)s=ρ(1−cosLρ)(6)tos=EImeϕ0hw2sin2(meϕ0hwL2EI)where k0, ke and α are material constant, m0 = k0keα, w is width, Mk and Me are the bending moment, ρ is radius of curvature, E is Young's modulus, I is moment of inertia, and s is max tip displacement as shown in Figure 4. From Equations (2) and (3), we let . Then after taking it into Equation (5) and simplifying it by the triangle formula, Equation (6) can be finally derived. Equation (6) is approximately linear with low applied voltage. Voltages of less than 10 V make this approximation valid. The voltage is limited by the electrolysis of water, so we didn't apply any voltage larger than 5 V:(7)s≅meϕ0hwL2EI=32meϕ0L2Eh2∝L2h2ϕ0

Bottom Line: Finally, a gear shaped IPMC actuator was designed and tested.Optical power of the IPMC deformable mirror is experimentally demonstrated to be 17 diopters with two volts.The needed voltage was about two orders lower than conventional silicon deformable mirrors and about one order lower than the liquid lens.

View Article: PubMed Central - PubMed

Affiliation: Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Roosevelt Road, Section 4, Taipei 10617, Taiwan. d96941017@ntu.edu.tw

ABSTRACT
Conventional camera modules with image sensors manipulate the focus or zoom by moving lenses. Although motors, such as voice-coil motors, can move the lens sets precisely, large volume, high power consumption, and long moving time are critical issues for motor-type camera modules. A deformable mirror (DM) provides a good opportunity to improve these issues. The DM is a reflective type optical component which can alter the optical power to focus the lights on the two dimensional optical image sensors. It can make the camera system operate rapidly. Ionic polymer metal composite (IPMC) is a promising electro-actuated polymer material that can be used in micromachining devices because of its large deformation with low actuation voltage. We developed a convenient simulation model based on Young's modulus and Poisson's ratio. We divided an ion exchange polymer, also known as Nafion(®), into two virtual layers in the simulation model: one was expansive and the other was contractive, caused by opposite constant surface forces on each surface of the elements. Therefore, the deformation for different IPMC shapes can be described more easily. A standard experiment of voltage vs. tip displacement was used to verify the proposed modeling. Finally, a gear shaped IPMC actuator was designed and tested. Optical power of the IPMC deformable mirror is experimentally demonstrated to be 17 diopters with two volts. The needed voltage was about two orders lower than conventional silicon deformable mirrors and about one order lower than the liquid lens.

No MeSH data available.