• Title/Summary/Keyword: Compact camera module

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Development of Compact Auto Focus Actuator for Camera Phone by Applying New Electromagnetic Configuration

  • Chung, Myung-Jin;Son, Sung-Yong
    • Journal of Mechanical Science and Technology
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    • v.20 no.12
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    • pp.2087-2093
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    • 2006
  • In this paper, auto focus actuator, which is used to move a lens module in the mobile phone having a camera module, is developed. Camera module containing auto focus actuator requires to minimize total size because of characteristics of the application area such as mobile phone, digital camera, and personal digital assistant. There are stepping motor, voice coil motor, and piezoelectric motor as auto focus actuator. In this paper, voice coil motor having new electromagnetic configuration is proposed. And actuator using proposed voice coil motor is developed by optimal design method using magnetic circuit analysis. The sectional area of the developed actuator is reduced to 32.4% compared with actuator using general electromagnetic configuration. From the performance test, the developed actuator has moving stroke of 0.64 mm for 2.1 volt, hysteresis of 40 $\mu$m, full stroke current of 54 mA, and unit step motion of 3 $\mu$m.

Fabrication of the Imaging Lens for Mobile Camera using Embossing Method (엠보싱 공법에 의한 카메라 모듈용 광학렌즈 성형기법에 대한 연구)

  • Lee, C.H.;Jin, Y.S.;Noh, J.E.;Kim, S.H.;Jang, I.C.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.05a
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    • pp.79-83
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    • 2007
  • We have developed a compact and cost-effective camera module on the basis of wafer-scale replication technology. A multiple-layered structure of several aspheric lenses in a mobile camera module is first assembled by bonding multiple glass-wafers on which 2-dimensional replica arrays of identical aspheric lenses are UV-embossed, followed by dicing the stacked wafers and packaging them with image sensor chips. We have demonstrated a VGA camera module fabricated by the wafer-scale replication processing with various UV-curable polymers having refractive indices between 1.4 and 1.6, and with three different glass-wafers of which both surfaces are embossed as aspheric lenses having 200 um sag-height and aspheric-coefficients of lens polynomials up to tenth-order. We have found that precise compensation in material shrinkage of the polymer materials is one of the most technical challenges, in order to achieve a higher resolution in wafer-scaled lenses for mobile camera modules.

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Improvement of Dynamic Characteristics of OIS System using Improved Band Notch and Analysis of Images (노치 대역을 개선한 이미지 흔들림 보정 장치의 동특성 향상과 이미지 분석)

  • Son, Dong-Hun;Park, No-Cheol;Park, Young-Pil;Park, Kyoung-Su
    • Transactions of the Society of Information Storage Systems
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    • v.7 no.2
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    • pp.70-74
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    • 2011
  • The mobile camera module is a device to be inserted in the digital device for camera feature. The mobile camera module is being shaken by vibrations such as handshake during the exposure time. The clarity is compromised by these vibrations, thus the vibration is considered as an external disturbance. Moreover the use of mobile camera module has been being expanded for automotive vibration should be considered. These external disturbances can cause image blurring, thus optical image stabilization should be applied for image compensation. The compensator is fulfilled mechanically by movable lens group or image sensor that adjusts the optical path to the camera movement. Open loop control is useful for well-defined systems like compliant mechanism. Notch filter and lead compensator are designed and applied to improve the stability and bandwidth. The final level of image compensating is confirmed by image processing with MATLAB and CODE V to verify the better performance.

A Fuzzy Search Method for Auto Focusing of CCM Test Handlers (CCM 테스트 핸들러의 자동초점조절을 위한 퍼지탐색 방법)

  • Kwon, Hyuk-Joong;Yoon, Hee-Sang;Park, Tae-Hyoung
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.11
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    • pp.1112-1118
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    • 2007
  • We propose a new-focusing method for test handlers of compact camera module (CCM), The MMD (max-min difference) method is applied to calculate the focus value quickly considering the noisy output of CCM. Also, the fuzzy search method is applied to find the maximum focus value effectively. We design a fuzzy processor to control the lens position by focus values and brightness values, which improves the focusing performance in the sense of speed and processor memory. The proposed method is implemented by computer program and installed at the CCM test handler machines. The simulation results are presented to verify the usefulness of the proposed method.

An Auto-Focusing Method for CCM Test Handlers (소형 카메라 모듈용 테스트 핸들러의 자동 초점 조절 방법)

  • Yoon Ree-Sang;Park Tae-Ryoung
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.2
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    • pp.168-173
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    • 2006
  • This paper proposes an auto-focusing method for production of compact camera module (CCM). The CCM test handlers are mainly used in the final CCM production stage to test and adjust the lens focus of CCMs. To improve the productivity of CCM test handlers, we propose the auto-focusing method adjusting the lens focus efficiently. The max-min-difference (MMD) method is newly developed to compute the focus value efficiently, and two-stage searching method is also developed to find the best focus position quickly. Experimental results are presented to verify the usefulness of proposed method.

A Study on the Assembly Process and Reliability of COF (Chip-On-Flex) Using ACFs (Anisotropic Conductive Films) for CCM (Compact Camera Module) (ACF를 이용한 CCM (Compact Camera Module)용 COF(Chip-On-Flex) 실장 기술 및 신뢰성 연구)

  • Chung, Chang-Kyu;Paik, Kyung-Wook
    • Journal of the Microelectronics and Packaging Society
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    • v.15 no.2
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    • pp.7-15
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    • 2008
  • In this paper, the Chip-On-Flex (COF) assembly process using anisotropic conductive films (ACFs) was investigated and the reliability of COF assemblies using ACFs was evaluated. Thermo-mechanical properties of ACFs such as coefficient of thermal expansion (CTE), storage modulus (E'), and glass transition temperature $(T_g)$ were measured to investigate the effects of ACF material properties on the reliability of COF assemblies using ACFs. In addition, the bonding conditions for COF assemblies using ACFs such as time, temperature, and pressure were optimized. After the COF assemblies using ACFs were fabricated with optimized bonding conditions, reliability tests were then carried out. According to the reliability test results, COF assemblies using the ACF which had lower CTE and higher $T_g$ showed better thermal cycling reliability. Consequently, thermo-mechanical properties of ACFs, especially $T_g$, should be improved for high thermal cycling reliability of COF assemblies using ACFs for compact camera module (CCM) applications.

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Compact Zoom Lens Design for a 5x Mobile Camera Using Prism

  • Park, Sung-Chan;Lee, Sang-Hun;Kim, Jong-Gyu
    • Journal of the Optical Society of Korea
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    • v.13 no.2
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    • pp.206-212
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    • 2009
  • This study presents the compact zoom lens with a zoom ratio of 5x for a mobile camera by using a prism. The lens modules and aberrations are applied to the initial design for a four-group inner-focus zoom system. An initial design with a focal length range of 4.4 to 22.0 mm is derived by assigning the first-order quantities and third-order aberrations to each module along with the constraints required for optimum solutions. We separately designed a real lens for each group and then combined them to establish an actual zoom system. The combination of the separately designed groups results in a system that satisfies the basic properties of the zoom system consisting of the original lens modules. In order to have a slim system, we directly inserted the right-angle prism in front of the first group. This configuration resulted in a more compact zoom system with a depth of 8 mm. The finally designed zoom lens has an f-number of 3.5 to 4.5 and is expected to fulfill the requirements for a slim mobile zoom camera having high zoom ratio of 5x.

Improvement of Dynamic Characteristics of an Optical Image Stabilizer in a Compact Camera (초소형 카메라 흔들림 보정장치의 동특성 개선)

  • Song, Myeong-Gyu;Son, Dong-Hun;Park, No-Cheol;Park, Kyoung-Su;Park, Young-Pil
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.2
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    • pp.178-185
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    • 2011
  • Optical image stabilization is a device to compensate the camera movement in the exposure time. The compensation is implemented by movable lens or image sensor that adjusts the optical path to the camera movement. Generally, the camera is moved by a handshake, thus the handshake is considered as an external disturbance. However, there are many other vibrations such as car and train vibration. In this paper, the optical image stabilization system in high frequency region is presented. Notch filter and lead compensator are designed and applied to improve the stability without changing the actuator. To verify the performance of the optical image stabilization system in high frequency region, the experiment equipment with moving object is established. It is confirmed that the opticalimage stabilization system does not diverge at the resonance frequency.