A Study of the Applications for Holographic Optical Elements on Optical Pickup Heads

• Main Authors: HSI-FU SHIH, 施錫富
• Other Authors: MING-WEN CHANG
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/27411801807403951297

博士 === 國立中央大學 === 光電科學研究所 === 87 === The early pickup heads are composed of conventional optical elements, therefore they have large volume and heavy weight. Recently, some of the conventional optical elements have been replaced with diffractive optical elements (DOEs) and holographic optical elements (HOEs) gradually. That makes the optical head system design toward minimizing and being modularized. Under this situation, HOEs are used gradually in the design of optical pickup heads to make it toward multifunction as well. Based on the optical pickup head techniques haven, this thesis studies the applications of HOEs on optical pickup heads: to study their good and bad points, to propose and establish some new concept, novel ideas and designs through theoretical deduction, computer simulation and experimental verification. They cover fundamental principles, HOE design methods, diffraction efficiency improvement, readout signal enhancement, laser feedback noise immunity, tolerance analysis and two wavelength applications. Especially for digital versatile disc (DVD) pickup heads, there are many useful designs been proposed. There are nine chapters. Chapter 1 and 2 are the fundamentals of optical head. Chapter 3 is the basis of holographic optical head design. Chapter 4 proposes a method for improving the diffraction efficiency of a holographic optical head. Chapter 5 and 6 are the HOE designs with robust focusing and tracking detection and high assembly tolerance. Chapter 7 proposes an easy method for laser feedback noise immunity. Chapter 8 is the holographic laser module design with dual wavelengths. The last Chapter is the conclusion. All the designs have been proved with computer simulations and experiments to show their practical feasiabilities.