Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Patent
1997-06-18
1999-01-26
Young, W. R.
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
369 4441, G11B 7095
Patent
active
058645250
ABSTRACT:
In an optical disk device for recording or playing back information on or from an optical information recording medium having land parts forming information tracks and groove parts interposed between adjacent land parts, the land part is illuminated with a first light spot, and the groove part is illuminated a second light spot, a first focus error signal is produced in accordance with the reflected light beam of the first light spot, and a second focus error signal is produced in accordance with the reflected light beam of the second light spot, and focus control is performed in accordance with the first and second focus error signals. In another aspect of the invention, each of the light receiving sections of a photodetector used for receiving the reflected light has an array of tapered projections along in a region between main parts the light receiving sections, and the tapered projections of the light receiving sections are interdigitated with each other. Improved devices for tilting the objective lens is also provided.
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Fujita Teruo
Takeshita Nobuo
Mitsubishi Denki & Kabushiki Kaisha
Young W. R.
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