Optical head with semiconductor laser

Details Optical head with semiconductor laser Optical head with semiconductor laser

1994-04-06

1995-04-11

LaRoche, Eugene R.

Dynamic information storage or retrieval

Specific detail of information handling portion of system

Radiation beam modification of or by storage medium

369122, 369103, 369109, 257 84, 257 85, 250551, G11B 700, H01L 3116

Patent

active

054065437

ABSTRACT:
An optical head for writing and/or reading information on and/or from an optical record medium such as a magneto-optical record medium including a semiconductor substrate, a semiconductor laser mounted on a surface of the semiconductor substrate for emitting a laser beam, an objective lens for projecting the laser beam onto the optical record medium as a fine spot, a plurality of photodetectors firmed in the surface of the semiconductor substrate, and an optical block arranged on said semiconductor substrate to form an integral unit together with said semiconductor substrate. The optical block includes a hologram for diffracting a return beam reflected by said magneto-optical record medium and a polarization beam splitting plane arranged in substantially parallel with an optical axis of a zero order beam emanating from the hologram for splitting a pupil of the hologram. The return beams diffracted by the hologram and split by the polarization beam splitting plane are separately received by the plurality of photodetectors. By processing outputs of the photodetectors, information signal, focusing error signal and tracking error signal can be derived in a reliable and stable manner, while the optical head can be simple in construction, small in size and cheap in cost.

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patent: 4967241 (1990-10-01), Kinoshita et al.
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H. Kosaka, et al, "A Single Vertical-Cavity Surface Emitting Laser and a Double Vertical-cavity Photo Transistor," Extended Abstracts (The 40th Spring Meeting, 1993); The Japan Society of Applied Physics and Related Societies, No. 3, JSAP Catalog Number: AP 931107-03.

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