Patent EP0313818A2 successfully refreshed from Google Patents.
EP0313818A2
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EP
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Optical information reading apparatus
Assignee: Pioneer Corp
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Filing: 1988-09-22
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Granted: —
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Expires: 2008-09-22
Abstract
Abstract Reduction of a number of parts required for servo control in an optical disk reproducing apparatus is achieved by deriving information relating to errors caused by warp or tilt of an optical disk from other error signals produced by other servo devices within the apparatus. A beam spot used to irradiate a disk surface is oscillated, and a frequency and amplitude component arising from this oscillation is extracted from the output of a light detector. The information provided by the frequency and amplitude may be used to compensate for tilt and warp, even though the detected signals are used for tracking and focusing servo devices in the optical disk apparatus. The technique is applicable to various types of discrete producing approaches, including a push-pull, a heterodyne system, and a three-beam system.
Inventors
- 👤 Satoshi Pioneer Electronic Corporation Sugiura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 19:47
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/095; G11B7/0956
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
194 words
An optical information reading apparatus comprising: an optical system for radiating a light beam in the form of a beam spot on an information recording surface of a disk-like recording medium; a light detector for receiving said light beam from said information recording surface; tracking error signal generating means for generating a tracking error signal corresponding to an amount of deviation of said beam spot from a recording track of said recording medium in accordance with an output of said light detector; tracking servo means for controlling a relative position of said beam spot relative to said recording track in accordance with said tracking error signal to minimize said amount of deviation; means for superimposing a driving signal of a predetermined frequency on said tracking error signal; extraction means for extracting a signal component of said predetermined frequency from the output of said light detector and providing an output signal accordingly; and detection means for detecting an amplitude and a phase of said extraction means output signal relative to said driving signal and providing an output signal accordingly, said tracking servo means adjusting said relative position in accordance with said detection means output signal.
Claim 2
Dependent Claim
194 words
An optical information reading apparatus comprising: an optical system for radiating a light beam in the form of a beam spot on an information recording surface of a disk-like recording medium; a light detector for receiving said light beam from said information recording surface; tracking error signal generating means for generating a tracking error signal corresponding to an amount of deviation of said beam spot from a recording track of said recording medium in accordance with an output of said light detector; tracking servo means for controlling a relative position of said beam spot relative to said recording track in accordance with said tracking error signal to minimize said amount of deviation; means for superimposing a driving signal of a predetermined frequency on said tracking error signal; extraction means for extracting a signal component of said predetermined frequency from the output of said light detector and providing an output signal accordingly; and detection means for detecting an amplitude and a phase of said extraction means output signal relative to said driving signal and providing an output signal accordingly, said tracking servo means adjusting said relative position in accordance with said detection means output signal.
Claim 3
Dependent Claim
216 words
An optical information reading apparatus comprising: an optical system for radiating a light beam in the form of a beam spot on an information recording surface of a disk-like recording medium; a light detector for receiving said light beam from said information recording surface; tracking error signal generating means for generating a tracking error signal corresponding to an amount of deviation of said beam spot from a recording track of said recording medium in accordance with an output of said light detector; tracking servo means for controlling a relative position of said beam spot relative to said recording track in accordance with said tracking error signal to minimize said amount of deviation; adjustment means for adjusting a tilt of an optical axis of the light beam relative to said information recording surface; means for superimposing a driving signal of a predetermined frequency on said tracking error signal; extraction means for extracting a signal component of said predetermined frequency from the output of said light detector and providing an output signal accordingly; and detection means for detecting an amplitude and a phase of said extraction means output signal relative to said driving signal and providing an output signal accordingly, said adjustment means adjusting said tilt of the optical axis in accordance with said detection means output signal.
Claim 4
Dependent Claim
216 words
An optical information reading apparatus comprising: an optical system for radiating a light beam in the form of a beam spot on an information recording surface of a disk-like recording medium; a light detector for receiving said light beam from said information recording surface; tracking error signal generating means for generating a tracking error signal corresponding to an amount of deviation of said beam spot from a recording track of said recording medium in accordance with an output of said light detector; tracking servo means for controlling a relative position of said beam spot relative to said recording track in accordance with said tracking error signal to minimize said amount of deviation; adjustment means for adjusting a tilt of an optical axis of the light beam relative to said information recording surface; means for superimposing a driving signal of a predetermined frequency on said tracking error signal; extraction means for extracting a signal component of said predetermined frequency from the output of said light detector and providing an output signal accordingly; and detection means for detecting an amplitude and a phase of said extraction means output signal relative to said driving signal and providing an output signal accordingly, said adjustment means adjusting said tilt of the optical axis in accordance with said detection means output signal.
Claim 5
Dependent Claim
233 words
An optical information reading apparatus comprising: an optical system for radiating a light beam in the form of a beam spot on an information recording surface of a disk-like recording medium; a light detector for receiving said light beam from said information recording surface; tracking error signal generating means for generating a tracking error signal corresponding to an amount of deviation of said beam spot from a recording track of said recording medium in accordance with an output of said light detector; tracking servo means for controlling a relative position of said beam spot relative to said recording track in accordance with said tracking error signal to minimize said amount of deviation; adjustment means for adjusting a tilt of an optical axis of the light beam relative to said information recording surface; means for superimposing a driving signal of a predetermined frequency on said tracking error signal; extraction means for extracting a signal component of said predetermined frequency from the output of said light detector and providing an output signal accordingly; and detection means for detecting an amplitude and a phase of said extraction means output signal relative to said driving signal and providing an output signal accordingly, said tracking servo means adjusting said relative position in accordance with said detection means output signal, and said adjustment means adjusting said tilt of the optical axis in accordance with said detection means output signal.
Claim 6
Dependent Claim
233 words
An optical information reading apparatus comprising: an optical system for radiating a light beam in the form of a beam spot on an information recording surface of a disk-like recording medium; a light detector for receiving said light beam from said information recording surface; tracking error signal generating means for generating a tracking error signal corresponding to an amount of deviation of said beam spot from a recording track of said recording medium in accordance with an output of said light detector; tracking servo means for controlling a relative position of said beam spot relative to said recording track in accordance with said tracking error signal to minimize said amount of deviation; adjustment means for adjusting a tilt of an optical axis of the light beam relative to said information recording surface; means for superimposing a driving signal of a predetermined frequency on said tracking error signal; extraction means for extracting a signal component of said predetermined frequency from the output of said light detector and providing an output signal accordingly; and detection means for detecting an amplitude and a phase of said extraction means output signal relative to said driving signal and providing an output signal accordingly, said tracking servo means adjusting said relative position in accordance with said detection means output signal, and said adjustment means adjusting said tilt of the optical axis in accordance with said detection means output signal.
Claim 7
Dependent Claim
57 words
An optical information reading apparatus as claimed in claim 3, in which when said detection means output signal includes a relatively low frequency component, then said adjustment means adjusts said tilt of the optical axis, and when said detection means output signal includes a relatively high frequency component, then said tracking servo means adjusts said relative position.
Claim 8
Dependent Claim
33 words
An optical information reading apparatus as claimed in claim 5, further comprising: supply means for alternatively supplying said detection means output signal to one of said tracking servo means and said adjustment means.
Claim 9
Dependent Claim
55 words
An optical information reading apparatus as claimed in claim 5, in which if recorded information is analog information, then said supply means supplies said detection means output signal to said adjustment means, and if the recorded information is digital information, then said supply means supplies said detection means output signal to said tracking servo means.
References Cited (Backward Citations)
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