Miniaturized auto-focusing VCM actuator with zero holding current.
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.
Liu
Chien-Sheng
CS
Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan. chienshengliu@itri.org.tw
Lin
Psang Dain
PD
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