title: Thin autofocus camera module by a large-stroke micromachined deformable mirror.
abstract: The conventional auto-focus and zoom image systems were made by a set of motor-moved lenses. Because of mechanical moving parts, it is not easy to miniaturize their sizes. In this paper, we propose a thin autofocus system using a large stroke MEMS (micro-electro-mechanical systems) deformable mirror which has the potential to downscale the size and to minimize chromatic aberration. The large stroke MEMS deformable mirror is made by a polyimide membrane that has a maximum 12 microm displacement over a 3 mm aperture. The module size is 5.4 mm thick in optical design layout and 6.7 mm after packaging. This autofocus system is designed with the f-number=4.13, on-axis MTF=0.28 at full frequency of 230 cycles/mm, and incident light within+/-26 degree. The position of clear image can vary from 4 cm to 50 cm achieved by controlling the surface curvature of the MEMS deformable mirror.
authors.affiliation: Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617 Taiwan.
authors.forename: Hsin-Ta
authors.initials: HT
authors.lastname: Hsieh
authors.forename: Hsiang-Chun
authors.initials: HC
authors.lastname: Wei
authors.forename: Meng-Hsuan
authors.initials: MH
authors.lastname: Lin
authors.forename: Wei-Yao
authors.initials: WY
authors.lastname: Hsu
authors.forename: Yuan-Chieh
authors.initials: YC
authors.lastname: Cheng
authors.forename: Guo-Dung John
authors.initials: GD
authors.lastname: Su
mesh_terms: D017076:Computer-Aided Design; D055119:Elastic Modulus; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D007909:Lenses; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D008904:Miniaturization; D010781:Photography / Q000295:instrumentation*