著者

Sun Wen-Shing Lin Yan-Nan Chang Jenq-Yang

出版者

Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physics

雑誌

Jpn J Appl Phys (ISSN:00214922)

巻号頁・発行日

vol.50, no.9, pp.09MA03-09MA03-9, 2011-09-25

被引用文献数

1

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An optical design is developed for a Blu-ray pickup head with a laser expander that can synchronously detect the linear displacement and two-dimensional angular tilts at the test plane. To improve the signal accuracy of the photo detector, a laser expander is used to transform the shape of the laser beam from elliptical to circular. A quadrant detector as used to detect the relative relationship between the $V_{\text{A}}$, $V_{\text{B}}$, $V_{\text{C}}$, $V_{\text{D}}$ signals, can be used to measure the tilt angle and displacement at the test plane. Measurement detection and analysis is based on one normalized focus error signal (NFES) and two angular signals. The optical efficiency of the Blu-ray pickup head with laser expander is 59.29%. The optical efficiency of the currently used commercial pickup head is only 8.08%. Tolerance analysis is also considered in the performance requirements.