Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Patent
1991-06-11
1993-06-08
Psitos, Aristotelis
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
369 4429, 369 4432, 2502015, G11B 709
Patent
active
052185885
ABSTRACT:
A focus offset correction method for optical information read/write device, the device comprising: a first amplitude detection circuit for detecting amplitude of a tracking error signal obtained from a record medium; a second amplitude detection circuit for detecting amplitude of an information reading signal; a tracking servo circuit for moving a laser beam to follow fluctuation of a track on the record medium; a focus servo circuit for controlling the laser beam so that a beam waist thereof is positioned on the record medium; and an offset adder for applying an offset to the focus servo circuit. The focus offset correction method comprises a first process for determining a range of the offset in which range an output from the first amplitude detection circuit always exceeds a predetermined value; and a second process for determining the offset which makes an output from the second amplitude detection circuit almost maximum.
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U.S. Serial No. 07/624,885, filed on Dec. 3, 1990.
U.S. Ser. No. 07/644,948, filed on Jan. 23, 1991.
Edun Muhammad N.
Psitos Aristotelis
Ricoh & Company, Ltd.
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