Abstract

In keeping with consumer preferences for ever smaller electronic products, a requirement exists for compact, high-performance auto-focusing actuators for the camera modules deployed in cell phones. Accordingly, the present study proposes a miniaturized electromagnetic-based actuator comprising a voice coil motor (VCM) and a closed-loop position control system in which an auto-focusing capability is achieved by using a position feedback signal generated by a Hall element to dynamically adjust the position of the lens module. The experimental results show that the holding current required to maintain a lens module weighing 200 mgw in the vertical position is 17 mA ±2 mA. Compared to conventional VCM actuators deployed in cell phone camera applications, the actuator presented in this study has a smaller size (6.5 mm×6.5 mm×4 mm) and an improved power efficiency. In particular, the miniaturized actuator reduces the holding current required to maintain the lens module in the focusing position by around 75% of that required in a traditional actuator.

© 2008 Optical Society of America

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  1. H. Ren, D. Fox, P. A. Anderson, B. Wu, and S. T. Wu, "Tunable-focus liquid lens controlled using a servo motor," Opt. Express 14, 8031-8036 (2006).
    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]
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    [CrossRef]
  5. S. W. Lee, and S. S. Lee, "Focal tunable liquid lens integrated with an electromagnetic actuator," Appl. Phys. Lett. 90, 121129 (2007).
    [CrossRef]
  6. S. M. Sohn, S. H. Yang, S. W. Kim, K. H. Baek and W. H. Paik, "SoC design of an auto-focus driving image signal processor for mobile camera applications," IEEE Trans. on Consumer Electronics 52, 10-16(2006).
    [CrossRef]
  7. C. W. Chiu, P. C. P. Chao, and D. Y. Wu, "Optimal design of magnetically actuated optical image stabilizer mechanism for cameras in mobile phones via genetic algorithm," IEEE Trans. Magn. 43, 2582-2584 (2007).
    [CrossRef]
  8. S. Manabu, and Y. Morimasa, "Lens drive device," PAJ2002-365514 (2002).
  9. S. M. Jang, J. Y. Choi, S. H. Lee, H. W. Cho, and W. B. Jang, "Analysis and experimental verification of moving-magnet linear actuator with cylindrical Halbach array," IEEE Trans. Mag. 40, 2068-2070 (2004).
    [CrossRef]
  10. Y. Hirano and J. Naurse, "Dynamic characteristics of a voice coil motor for a high performance disk drive," IEEE Trans. Mag. 25, 3073-3075 (1989).
    [CrossRef]
  11. H. C. Yu, T. Y. Lee, S. J. Wang, M. L. Lai, J. J. Ju, D. R. Huang, and S. K. Lin, "Design of a voice coil motor used in the focusing system of a digital video camera," IEEE Trans. Mag.  41, 3979-3981 (2005).
    [CrossRef]
  12. H. C. Yu, T. Y. Lee, S. K. Lin, L.T. Kuo, S. J. Wang, J. J. Ju, and D. R. Huang, "Low power consumption focusing actuator for a mini video camera," J. Appl. Phys., 99, 08R901 (2006).
    [CrossRef]
  13. M. J. Chung, "Development of compact auto focus actuator for camera phone by applying new electromagnetic configuration," Proc. SPIE  6048, 60480J (2005).
    [CrossRef]
  14. http://www.shicoh.com/e/index.ht.
  15. Standard Mobile Imaging Architecture, http://www.smia-forum.org/.

2007

K. Campbell, Y. Fainman, and A. Groisman, "Pneumatically actuated adaptive lenses with millisecond response time," Appl. Phys. Lett. 91, 171111 (2007).
[CrossRef]

S. W. Lee, and S. S. Lee, "Focal tunable liquid lens integrated with an electromagnetic actuator," Appl. Phys. Lett. 90, 121129 (2007).
[CrossRef]

C. W. Chiu, P. C. P. Chao, and D. Y. Wu, "Optimal design of magnetically actuated optical image stabilizer mechanism for cameras in mobile phones via genetic algorithm," IEEE Trans. Magn. 43, 2582-2584 (2007).
[CrossRef]

H. Ren and S. T. Wu, "Variable-focus liquid lens," Opt. Express 15, 5931-5936 (2007).
[CrossRef] [PubMed]

2006

2005

H. C. Yu, T. Y. Lee, S. J. Wang, M. L. Lai, J. J. Ju, D. R. Huang, and S. K. Lin, "Design of a voice coil motor used in the focusing system of a digital video camera," IEEE Trans. Mag.  41, 3979-3981 (2005).
[CrossRef]

M. J. Chung, "Development of compact auto focus actuator for camera phone by applying new electromagnetic configuration," Proc. SPIE  6048, 60480J (2005).
[CrossRef]

2004

S. M. Jang, J. Y. Choi, S. H. Lee, H. W. Cho, and W. B. Jang, "Analysis and experimental verification of moving-magnet linear actuator with cylindrical Halbach array," IEEE Trans. Mag. 40, 2068-2070 (2004).
[CrossRef]

2002

S. Manabu, and Y. Morimasa, "Lens drive device," PAJ2002-365514 (2002).

1989

Y. Hirano and J. Naurse, "Dynamic characteristics of a voice coil motor for a high performance disk drive," IEEE Trans. Mag. 25, 3073-3075 (1989).
[CrossRef]

Anderson, P. A.

Baek, K. H.

S. M. Sohn, S. H. Yang, S. W. Kim, K. H. Baek and W. H. Paik, "SoC design of an auto-focus driving image signal processor for mobile camera applications," IEEE Trans. on Consumer Electronics 52, 10-16(2006).
[CrossRef]

Campbell, K.

K. Campbell, Y. Fainman, and A. Groisman, "Pneumatically actuated adaptive lenses with millisecond response time," Appl. Phys. Lett. 91, 171111 (2007).
[CrossRef]

Chang, C. A.

Chao, P. C. P.

C. W. Chiu, P. C. P. Chao, and D. Y. Wu, "Optimal design of magnetically actuated optical image stabilizer mechanism for cameras in mobile phones via genetic algorithm," IEEE Trans. Magn. 43, 2582-2584 (2007).
[CrossRef]

Cheng, C. C.

Chiu, C. W.

C. W. Chiu, P. C. P. Chao, and D. Y. Wu, "Optimal design of magnetically actuated optical image stabilizer mechanism for cameras in mobile phones via genetic algorithm," IEEE Trans. Magn. 43, 2582-2584 (2007).
[CrossRef]

Cho, H. W.

S. M. Jang, J. Y. Choi, S. H. Lee, H. W. Cho, and W. B. Jang, "Analysis and experimental verification of moving-magnet linear actuator with cylindrical Halbach array," IEEE Trans. Mag. 40, 2068-2070 (2004).
[CrossRef]

Choi, J. Y.

S. M. Jang, J. Y. Choi, S. H. Lee, H. W. Cho, and W. B. Jang, "Analysis and experimental verification of moving-magnet linear actuator with cylindrical Halbach array," IEEE Trans. Mag. 40, 2068-2070 (2004).
[CrossRef]

Chung, M. J.

M. J. Chung, "Development of compact auto focus actuator for camera phone by applying new electromagnetic configuration," Proc. SPIE  6048, 60480J (2005).
[CrossRef]

Fainman, Y.

K. Campbell, Y. Fainman, and A. Groisman, "Pneumatically actuated adaptive lenses with millisecond response time," Appl. Phys. Lett. 91, 171111 (2007).
[CrossRef]

Fox, D.

Groisman, A.

K. Campbell, Y. Fainman, and A. Groisman, "Pneumatically actuated adaptive lenses with millisecond response time," Appl. Phys. Lett. 91, 171111 (2007).
[CrossRef]

Hirano, Y.

Y. Hirano and J. Naurse, "Dynamic characteristics of a voice coil motor for a high performance disk drive," IEEE Trans. Mag. 25, 3073-3075 (1989).
[CrossRef]

Huang, D. R.

H. C. Yu, T. Y. Lee, S. J. Wang, M. L. Lai, J. J. Ju, D. R. Huang, and S. K. Lin, "Design of a voice coil motor used in the focusing system of a digital video camera," IEEE Trans. Mag.  41, 3979-3981 (2005).
[CrossRef]

H. C. Yu, T. Y. Lee, S. K. Lin, L.T. Kuo, S. J. Wang, J. J. Ju, and D. R. Huang, "Low power consumption focusing actuator for a mini video camera," J. Appl. Phys., 99, 08R901 (2006).
[CrossRef]

Jang, S. M.

S. M. Jang, J. Y. Choi, S. H. Lee, H. W. Cho, and W. B. Jang, "Analysis and experimental verification of moving-magnet linear actuator with cylindrical Halbach array," IEEE Trans. Mag. 40, 2068-2070 (2004).
[CrossRef]

Jang, W. B.

S. M. Jang, J. Y. Choi, S. H. Lee, H. W. Cho, and W. B. Jang, "Analysis and experimental verification of moving-magnet linear actuator with cylindrical Halbach array," IEEE Trans. Mag. 40, 2068-2070 (2004).
[CrossRef]

Ju, J. J.

H. C. Yu, T. Y. Lee, S. J. Wang, M. L. Lai, J. J. Ju, D. R. Huang, and S. K. Lin, "Design of a voice coil motor used in the focusing system of a digital video camera," IEEE Trans. Mag.  41, 3979-3981 (2005).
[CrossRef]

H. C. Yu, T. Y. Lee, S. K. Lin, L.T. Kuo, S. J. Wang, J. J. Ju, and D. R. Huang, "Low power consumption focusing actuator for a mini video camera," J. Appl. Phys., 99, 08R901 (2006).
[CrossRef]

Kim, S. W.

S. M. Sohn, S. H. Yang, S. W. Kim, K. H. Baek and W. H. Paik, "SoC design of an auto-focus driving image signal processor for mobile camera applications," IEEE Trans. on Consumer Electronics 52, 10-16(2006).
[CrossRef]

Kuo, L. T.

H. C. Yu, T. Y. Lee, S. K. Lin, L.T. Kuo, S. J. Wang, J. J. Ju, and D. R. Huang, "Low power consumption focusing actuator for a mini video camera," J. Appl. Phys., 99, 08R901 (2006).
[CrossRef]

Lai, M. L.

H. C. Yu, T. Y. Lee, S. J. Wang, M. L. Lai, J. J. Ju, D. R. Huang, and S. K. Lin, "Design of a voice coil motor used in the focusing system of a digital video camera," IEEE Trans. Mag.  41, 3979-3981 (2005).
[CrossRef]

Lee, S. H.

S. M. Jang, J. Y. Choi, S. H. Lee, H. W. Cho, and W. B. Jang, "Analysis and experimental verification of moving-magnet linear actuator with cylindrical Halbach array," IEEE Trans. Mag. 40, 2068-2070 (2004).
[CrossRef]

Lee, Seok Woo

S. W. Lee, and S. S. Lee, "Focal tunable liquid lens integrated with an electromagnetic actuator," Appl. Phys. Lett. 90, 121129 (2007).
[CrossRef]

Lee, Seung S.

S. W. Lee, and S. S. Lee, "Focal tunable liquid lens integrated with an electromagnetic actuator," Appl. Phys. Lett. 90, 121129 (2007).
[CrossRef]

Lee, T. Y.

H. C. Yu, T. Y. Lee, S. J. Wang, M. L. Lai, J. J. Ju, D. R. Huang, and S. K. Lin, "Design of a voice coil motor used in the focusing system of a digital video camera," IEEE Trans. Mag.  41, 3979-3981 (2005).
[CrossRef]

H. C. Yu, T. Y. Lee, S. K. Lin, L.T. Kuo, S. J. Wang, J. J. Ju, and D. R. Huang, "Low power consumption focusing actuator for a mini video camera," J. Appl. Phys., 99, 08R901 (2006).
[CrossRef]

Lin, S. K.

H. C. Yu, T. Y. Lee, S. J. Wang, M. L. Lai, J. J. Ju, D. R. Huang, and S. K. Lin, "Design of a voice coil motor used in the focusing system of a digital video camera," IEEE Trans. Mag.  41, 3979-3981 (2005).
[CrossRef]

H. C. Yu, T. Y. Lee, S. K. Lin, L.T. Kuo, S. J. Wang, J. J. Ju, and D. R. Huang, "Low power consumption focusing actuator for a mini video camera," J. Appl. Phys., 99, 08R901 (2006).
[CrossRef]

Manabu, S.

S. Manabu, and Y. Morimasa, "Lens drive device," PAJ2002-365514 (2002).

Morimasa, Y.

S. Manabu, and Y. Morimasa, "Lens drive device," PAJ2002-365514 (2002).

Naurse, J.

Y. Hirano and J. Naurse, "Dynamic characteristics of a voice coil motor for a high performance disk drive," IEEE Trans. Mag. 25, 3073-3075 (1989).
[CrossRef]

Paik, W. H.

S. M. Sohn, S. H. Yang, S. W. Kim, K. H. Baek and W. H. Paik, "SoC design of an auto-focus driving image signal processor for mobile camera applications," IEEE Trans. on Consumer Electronics 52, 10-16(2006).
[CrossRef]

Ren, H.

Sohn, S. M.

S. M. Sohn, S. H. Yang, S. W. Kim, K. H. Baek and W. H. Paik, "SoC design of an auto-focus driving image signal processor for mobile camera applications," IEEE Trans. on Consumer Electronics 52, 10-16(2006).
[CrossRef]

Wang, S. J.

H. C. Yu, T. Y. Lee, S. J. Wang, M. L. Lai, J. J. Ju, D. R. Huang, and S. K. Lin, "Design of a voice coil motor used in the focusing system of a digital video camera," IEEE Trans. Mag.  41, 3979-3981 (2005).
[CrossRef]

H. C. Yu, T. Y. Lee, S. K. Lin, L.T. Kuo, S. J. Wang, J. J. Ju, and D. R. Huang, "Low power consumption focusing actuator for a mini video camera," J. Appl. Phys., 99, 08R901 (2006).
[CrossRef]

Wu, B.

Wu, D.Y.

C. W. Chiu, P. C. P. Chao, and D. Y. Wu, "Optimal design of magnetically actuated optical image stabilizer mechanism for cameras in mobile phones via genetic algorithm," IEEE Trans. Magn. 43, 2582-2584 (2007).
[CrossRef]

Wu, S. T.

Yang, S. H.

S. M. Sohn, S. H. Yang, S. W. Kim, K. H. Baek and W. H. Paik, "SoC design of an auto-focus driving image signal processor for mobile camera applications," IEEE Trans. on Consumer Electronics 52, 10-16(2006).
[CrossRef]

Yeh, J. A.

Yu, H. C.

H. C. Yu, T. Y. Lee, S. J. Wang, M. L. Lai, J. J. Ju, D. R. Huang, and S. K. Lin, "Design of a voice coil motor used in the focusing system of a digital video camera," IEEE Trans. Mag.  41, 3979-3981 (2005).
[CrossRef]

H. C. Yu, T. Y. Lee, S. K. Lin, L.T. Kuo, S. J. Wang, J. J. Ju, and D. R. Huang, "Low power consumption focusing actuator for a mini video camera," J. Appl. Phys., 99, 08R901 (2006).
[CrossRef]

Appl. Phys. Lett.

K. Campbell, Y. Fainman, and A. Groisman, "Pneumatically actuated adaptive lenses with millisecond response time," Appl. Phys. Lett. 91, 171111 (2007).
[CrossRef]

S. W. Lee, and S. S. Lee, "Focal tunable liquid lens integrated with an electromagnetic actuator," Appl. Phys. Lett. 90, 121129 (2007).
[CrossRef]

IEEE Trans. Mag.

S. M. Jang, J. Y. Choi, S. H. Lee, H. W. Cho, and W. B. Jang, "Analysis and experimental verification of moving-magnet linear actuator with cylindrical Halbach array," IEEE Trans. Mag. 40, 2068-2070 (2004).
[CrossRef]

H. C. Yu, T. Y. Lee, S. J. Wang, M. L. Lai, J. J. Ju, D. R. Huang, and S. K. Lin, "Design of a voice coil motor used in the focusing system of a digital video camera," IEEE Trans. Mag.  41, 3979-3981 (2005).
[CrossRef]

IEEE Trans. Magn.

Y. Hirano and J. Naurse, "Dynamic characteristics of a voice coil motor for a high performance disk drive," IEEE Trans. Mag. 25, 3073-3075 (1989).
[CrossRef]

C. W. Chiu, P. C. P. Chao, and D. Y. Wu, "Optimal design of magnetically actuated optical image stabilizer mechanism for cameras in mobile phones via genetic algorithm," IEEE Trans. Magn. 43, 2582-2584 (2007).
[CrossRef]

IEEE Trans. on Consumer Electronics

S. M. Sohn, S. H. Yang, S. W. Kim, K. H. Baek and W. H. Paik, "SoC design of an auto-focus driving image signal processor for mobile camera applications," IEEE Trans. on Consumer Electronics 52, 10-16(2006).
[CrossRef]

Opt. Express

PAJ

S. Manabu, and Y. Morimasa, "Lens drive device," PAJ2002-365514 (2002).

Proc. SPIE

M. J. Chung, "Development of compact auto focus actuator for camera phone by applying new electromagnetic configuration," Proc. SPIE  6048, 60480J (2005).
[CrossRef]

Other

http://www.shicoh.com/e/index.ht.

Standard Mobile Imaging Architecture, http://www.smia-forum.org/.

H. C. Yu, T. Y. Lee, S. K. Lin, L.T. Kuo, S. J. Wang, J. J. Ju, and D. R. Huang, "Low power consumption focusing actuator for a mini video camera," J. Appl. Phys., 99, 08R901 (2006).
[CrossRef]

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Figures (9)

Fig. 1.
Fig. 1.

(a) Structure of conventional VCM actuator; (b) forces acting on conventional VCM actuator in vertical posture.

Fig. 2.
Fig. 2.

(a) Structure of proposed VCM actuator; (b) moving part; (c) fixed part.

Fig. 3.
Fig. 3.

Simulation results obtained for magnetic flux distribution in proposed VCM actuator.

Fig. 4.
Fig. 4.

Simulation results obtained for variation of Lorentz force FVCM with actuator displacement as function of holding current.

Fig. 5.
Fig. 5.

Electromagnetic design of proposed VCM actuator: (a) two permanent magnets and coils; (b) cross-sectional view.

Fig. 6.
Fig. 6.

Photograph of VCM Actuator.

Fig. 7.
Fig. 7.

Block diagram showing experiment setup used in characterization trials.

Fig. 8.
Fig. 8.

Experimental results obtained for variation of measured holding current with actuator displacement.

Fig. 9.
Fig. 9.

(a) Experimental setup used for testing auto-focusing performance of proposed VCM actuator; (b) experimental results obtained without (upper) and with (lower) auto-focusing function enabled, respectively.

Tables (1)

Tables Icon

Table 1. Design parameters of proposed VCM actuator.

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