本文研究的架構分成兩大部份，一部份是微型音圈馬達自動對焦致動器的設計，另一部份是鏡頭模組的光學特性分析。
自動對焦致動器在相機系統中是基本配備，主要功能在於調整焦距，改善成像品質；應用在手機相機中則要求微型、高性能的自動對焦致動器。因此，本文研究的架構首先發表用於手機相機之小型電磁式自動對焦致動器，它包含一音圈馬達及一閉迴路定位控制系統。該閉迴路控制系統是藉由一霍爾元件的輸出訊號（電壓）當回饋訊號，來調整移動件的位置，以達到自動對焦的功能。實驗結果顯示，跟已知的開迴路音圈馬達致動器比較起來，本文之致動器的體積較小、定位重複精度較高且能耗較低。
影響手機相機成像品質的另一個因素是鏡頭模組本身的光學特性；點擴散函數和調制轉換函數是基本的衡量指標。點擴散函數在成像理論中扮演一個重要的角色，因為它代表一個光學系統對一點光源的反應能力。調制轉換函數代表一個光學系統對測試物的對比度反應能力，它可以藉由亮度分佈函數與線擴散函數的迴旋運算來得到。然而，推導點擴散函數與線擴散函數計算方法的文獻非常少，因此本文接著利用光能量守恆的概念，透過光線追蹤，推導出一套新的點擴散函數計算方法與不需線擴散函數的調制轉換函數計算方法，並用自動對焦致動器的鏡頭模組來評估此方法的效能。結果顯示，跟已知的計算光線方法比較起來，本文之計算方法能得到較高的精度與較佳的效率。

This study includes two parts: Part I proposes miniaturized auto-focusing actuators for cell phone camera modules; and Part II presents the analysis of the optical performance of lens modules for cell phone camera modules.
Focus adjustment is one of the most basic functionalities in all imaging systems, and can be used to improve image quality. In particular, a requirement exists for compact, high-performance auto-focusing actuators for the camera modules deployed in cell phones. Therefore, this study presents novel miniaturized electromagnetic-based actuators comprised of a voice coil motor (VCM) and a closed-loop position control system in which 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 for auto-focusing cell phone camera modules. The results show that the proposed actuators are not only smaller than conventional VCM actuators with an open-loop positioning system, but also have improved positioning repeatability and lower power consumption.
Another factor that affects the image quality of cell phone camera modules is the performance of the lens module, in which the geometrical point spread function (PSF) and the modulation transfer function (MTF) are two basic concerns. The PSF plays an important role in the image formation theory, since it describes the impulse response of an optical system to a source point. The MTF is a measurement of an optical system’s ability to transfer contrast from the specimen to the image plane at a specific resolution. The MTF can be computed by convolution of the object brightness distribution function with the line spread function (LPS). However, very few techniques for deriving the PSF of optical systems and real LPSs are rarely (if ever) represented in the literature. In order to overcome these difficulties, this study then presents a new method based on an irradiance model for computing the geometrical PSF of an optical system by considering the energy conservation along a single light ray and a new MTF computation method of an optical system from ray-tracing data without its LPS.

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