音圈馬達應用於手機數位相機致動器之研究

Abstract

近年來，數位相機普遍安裝在手機中。數位相機之對焦功能是藉致動器移動鏡頭以達成。常用的鏡頭致動器包括音圈馬達、步進馬達和壓電馬達。相較於其他兩種致動器，音圈馬達具有價格最低、重現度最好及使用功率電晶體最少的優點。使用音圈馬達於手機數位相機中，因為手機中空間有限，音圈馬達的設計會面臨到有限空間的機構設計挑戰。機構設計不良會導致音圈馬達在做鏡頭的定位控制時，會有鏡頭搖晃的現象發生。鏡頭搖晃會導致影像成像不清晰。本研究探討音圈馬達的設計與控制。在設計方面，本研究提出一個音圈馬達設計，以有限元素方法分析此音圈馬達之磁場，並且製作了此設計的實體。此音圈馬達具有磁場遮蔽良好，功率損耗較低的優點。在定位控制方面，本研究以模糊控制方法，抑制鏡頭搖晃的現象，並使鏡頭的定位控制可以用較少的時間達成。

Recently, it is popular that a digital camera is installed in a mobile phone. In a digital camera, an actuator moves a lens to carry out focusing. Common lens actuators include stepper motor, voice coil motor, and piezo motor. Compared to actuators of the other two types, voice coil motors have advantages of lowest price, good repeatability and the least amount of usage of power transistors. For the design of voice coil motors in a digital camera, the researcher faces with the challenge because of limited space in a mobile phone. A bad design of voice coil motor causes the lens to shake when the lens is positioned. Shake of lens makes image vague. This study investigates design and positioning control of voice coil motors. Concerning design, this study designs a voice coil motor, uses finite element method to analyze its magnetic field, and fabricates the design. This design has advantages of good shield of magnetic field and low power consumption. In addition, concerning positioning control, this study uses fuzzy control to suppress shake of the lens, and spends less time to complete positioning control of the lens.