Affiliations: Department of Mechanical Engineering and Advanced Institute of Manufacturing with High-tech Innovations, National Chung Cheng University, Chiayi, Taiwan
Correspondence:
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Corresponding author: Chien-Sheng Liu, Department of Mechanical Engineering and Advanced Institute of Manufacturing with High-tech Innovations, National Chung Cheng University, No. 168, University Road, Minhsiung Township, Chiayi County 62102, Taiwan. Tel.: +886 5 2729306; Fax: +886 5 2720589; E-mail:imecsl@ccu.edu.tw
Abstract: The smart cell phone market has rapid growth in recent years and cell phone
camera modules have strong requirement for capturing images and
communication in our daily use. Accordingly, in the present study, a novel
compact voice coil motor (VCM) actuator is proposed for auto-focusing (AF)
of cell phone camera modules. Compared to conventional VCM actuators with
open-loop position control mechanism, the proposed VCM actuator is featured
with absence of spring plates. In the proposed approach, the magnetic
restoring force is used to replace the restoring force of the spring plates
in the open-loop control VCM actuators. The motivation of this study is to
characterize the performance of the proposed VCM actuator using simulation
methods and then evaluate experimentally this device using a
laboratory-built prototype. The results show that the proposed VCM actuator
has the sizes of 8.5 mm × 8.5 mm × 7.5 mm, the maximal input
current of 40 mA, the maximal response time of 10 ms, and the average
measured Lorentz force of 2200 mgw for the input current of 40 mA in its
whole displacement (stroke of 0.4 mm), and it operates the AF function well.
Keywords: Auto-focusing, voice coil motor, actuator, linear motors, phone cameras, open-loop control
