由於光儲存資訊系統已邁入高容量世代，為了增加儲存密度，讀取頭(Pickup-head)設計時可選用光源波長較短之雷射二極體或增加該讀取頭物鏡的數值孔徑，進而可達成縮小雷射光點。然而由於雷射二極體之共振腔結構使得出光光束呈現橢圓形光點，並且產生像散間距(astigmatism)，所以其光學系統之雷射二極體準直鏡的品質優劣會影響雷射光點大小甚鉅。因此，本文選用ROHM公司所生產型號為RLD65MPT7之雷射二極體作為光源，並搭配US Patent 6995929光碟讀取頭物鏡之孔徑大小進行單一鏡片之準直鏡的模擬設計，此準直鏡可將雷射二極體之雷射光修整為圓形平行光束並同時補償其像散間距。其圓形平行光束半徑預設計為2.2875 mm，而軟體計算之結果為2.29042 mm，其誤差值僅有0.13%。

Since Optical Information Storage System has advanced into a high volume era, in order to increase the storage density, during the design process of the Pickup-head we can either choose to use a laser diode which has shorter wavelength; or, we can increase the numerical aperture of the Objective lens. Both options allow us to decrease the spot size of the laser. However, owing to the special structure of the resonator in the laser diodes, the output beams of the laser diode are usually elliptically diverging with a certain amount of astigmatism. Therefore the collimator within the system has a major impact on the quality of the spot size. In conclusion, the purpose of this article is to design a single asymmetrical aspherical collimator with the laser diode of ROHM RLD65MPT7 and with the lens aperture of objective lens in US Patent 6995929. The expected value of diameter of circular-parallel output beam is 2.2875mm, and the value is 2.2904mm after computing. Hence, the error has only 0.13%.

目 錄
中文摘要
英文摘要
致謝
目錄
圖目錄
表目錄
第一章　緒論
第二章　雷射二極體
　2.1　雷射二極體之特性
2.2　雷射二極體之光學系統
2.2.1　讀取頭系統架構
　 2.2.2 雷射光斑
第三章　準直鏡設計理論
第四章　準直鏡設計
　4.1　雷射二極體設計
　4.2　準直鏡設計
第五章　結論
參考文獻

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