title: Miniaturized auto-focusing VCM actuator with zero holding current.
abstract: In keeping with consumers' preferences for electronic products of ever smaller size and enhanced functionality, it is necessary to reduce the profile of the auto-focusing actuators used in camera phones without sacrificing their performance. Accordingly, this study modifies the Voice Coil Motor (VCM) actuator proposed by the current group in a previous study (C. S. Liu and P. D. Lin, Opt. Express, 16, 2533-2540, 2008) to accomplish a miniaturized auto-focusing actuator for cell phone camera modules with minimal power consumption. The proposed device comprises a VCM, a closed-loop position control system, a magnetoconductive plate, and a lens support structure to drive the lens to the optimal focusing position. The experimental results show that the actuator has a zero holding current when maintaining the lens in the specified focusing position. Overall, it is shown that compared to existing VCM actuators, the proposed actuator has bo a higher power efficiency and an improved positioning repeatability.
authors.affiliation: Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan. chienshengliu@itri.org.tw
authors.forename: Chien-Sheng
authors.initials: CS
authors.lastname: Liu
authors.forename: Psang Dain
authors.initials: PD
authors.lastname: Lin
mesh_terms: D017076:Computer-Aided Design; D011211:Electric Power Supplies; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D007909:Lenses; D008280:Magnetics / Q000295:instrumentation*; D008904:Miniaturization; D010781:Photography / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers