US4888756A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical information recording and reproducing apparatus
Assignee: Canon Inc
•
Filing: 1988-12-30
•
Granted: 1989-12-19
•
Expires: 2008-12-30
Abstract
Abstract An optical information recording and reproducing apparatus for an optical information record medium on which a plurality of tracks are arranged substantially in parallel, comprises a light source, a first optical system for guiding a light beam from the light source, onto the record medium, a second optical system for obtaining the light beam from the record medium, a detecting device for receiving the light beam obtained by the second optical system to output at least one of a focusing signal and a tracking signal, an adjusting device for adjusting at least one of focusing and tracking operation in accordance with at least one of the focusing and tracking signals, a reciprocating device for causing the record medium to reciprocate, a control device for controlling the reciprocating device, and a change device for changing at least a servo gain of the adjusting device in accordance with at least a signal from the control device.
Inventors
- 👤 Satoshi Shikichi
- 👤 Hideki Hosoya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:50
CPC Classifications
G; G11; G11B; G11B19/00; G11B19/20; G11B7/00; G11B7/002; G11B7/0033; G11B7/08; G11B7/09; G11B7/0946
Claims Analysis
Total Claims: 51
Claim 1
Independent Claim
167 words
An optical information recording and reproducing apparatus for an optical record medium on which a plurality of tracks are arranged substantially in parallel, comprising: a light source for providing a light beam; first optical means for guiding the light beam from said light source onto the record medium; second optical means for acting on the light beam from the record medium; detecting means for receiving the light beam acted on by said second optical means for output at least one of a focussing signal and a tracking signal; adjusting means for adjusting at least one of focussing and tracking operations in accordance with at least one of the focussing and tracking signals; reciprocating means for providing relative reciprocatory motion between the record medium and the light beam; control means for controlling the reciprocating means; and switching means for switching at least a servo gain of said adjusting means from a first value to a second value in accordance with at least a signal from said control means.
Claim 2
Dependent Claim
167 words
An optical information recording and reproducing apparatus for an optical record medium on which a plurality of tracks are arranged substantially in parallel, comprising: a light source for providing a light beam; first optical means for guiding the light beam from said light source onto the record medium; second optical means for acting on the light beam from the record medium; detecting means for receiving the light beam acted on by said second optical means for output at least one of a focussing signal and a tracking signal; adjusting means for adjusting at least one of focussing and tracking operations in accordance with at least one of the focussing and tracking signals; reciprocating means for providing relative reciprocatory motion between the record medium and the light beam; control means for controlling the reciprocating means; and switching means for switching at least a servo gain of said adjusting means from a first value to a second value in accordance with at least a signal from said control means.
Claim 3
Dependent Claim
63 words
An apparatus according to claim 1, wherein said switching means includes first switch means for switching the servo gain of said adjusting means from the first value to the second value in accordance with a first signal from said control means and second switching means for switching the direction of the reciprocatory motion in accordance with a second signal from said control means.
Claim 4
Dependent Claim
63 words
An apparatus according to claim 1, wherein said switching means includes first switching means for switching the servo gain of said adjusting means from the first value to the second value in accordance with a first signal from said control means and second switching means for switching the speed of the reciprocatory motion in accordance with a second signal from said control means.
Claim 5
Dependent Claim
26 words
An apparatus according to claim 3, wherein the second value is less than the first value and the second speed is less than the first speed.
Claim 6
Dependent Claim
26 words
An apparatus according to claim 3, wherein the second value is greater than the first value and the second speed is greater than the first speed.
Claim 7
Dependent Claim
48 words
An apparatus according to claim 1, wherein said switching means switches said servo gain from the first value to the second value to be imparted to a servo mechanism at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
Claim 8
Dependent Claim
43 words
An apparatus according to claim 1, wherein said switching means switches said servo gain from the first value to the second value to be imparted to a servo mechanism with the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 9
Dependent Claim
178 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output at least one of a focussing signal and a tracking signal; a servo mechanism for adjusting at least one of focussing and tracking operations in accordance with at least one of the focussing and tracking signals output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for imparting a different servo gain to said servo mechanism for a predetermined time when a direction of the reciprocatory motion is changed.
Claim 10
Dependent Claim
178 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output at least one of a focussing signal and a tracking signal; a servo mechanism for adjusting at least one of focussing and tracking operations in accordance with at least one of the focussing and tracking signals output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for imparting a different servo gain to said servo mechanism for a predetermined time when a direction of the reciprocatory motion is changed.
Claim 11
Dependent Claim
34 words
An apparatus according to claim 8, wherein said circuit switches the servo gain of said servo mechanism from a first value to a second value in response to a signal from said control mechanism.
Claim 12
Dependent Claim
64 words
An apparatus according to claim 9, wherein said circuit includes a first switch system for switching the servo gain of said servo mechanism from the first value to the second value in response to a first signal from said control mechanism and a second switch system for switching the direction of the reciprocatory motion in response to a second signal from said control mechanism.
Claim 13
Dependent Claim
72 words
An apparatus according to claim 9, wherein said circuit includes a first switch system for switching the servo gain of said servo mechanism from the first value to the second value in response to a first signal from said control mechanism and a second switch system for switching the speed of the reciprocatory motion from a first speed to a second speed in response to a second signal from said control mechanism.
Claim 14
Dependent Claim
26 words
An apparatus according to claim 11, wherein the second value is less than said first value and the second speed is greater than the first speed.
Claim 15
Dependent Claim
157 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output a focussing signal; a servo mechanism for adjusting focussing operation in accordance with the focussing signal output by said photodetector; driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; control mechanism for controlling the driving means; and a circuit for imparting a different servo gain to said servo mechanism when the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 16
Dependent Claim
157 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output a focussing signal; a servo mechanism for adjusting focussing operation in accordance with the focussing signal output by said photodetector; driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; control mechanism for controlling the driving means; and a circuit for imparting a different servo gain to said servo mechanism when the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 17
Dependent Claim
34 words
An apparatus according to claim 13, wherein said circuit switches the servo gain of said servo mechanism from a first value to a second value in response to a signal from said control mechanism.
Claim 18
Dependent Claim
64 words
An apparatus according to claim 14, wherein said circuit includes a first switch system for switching the servo gain of said servo mechanism from the first value to the second value in response to a first signal from said control mechanism and a second switch system for switching the direction of the reciprocatory motion in response to a second signal from said control mechanism.
Claim 19
Dependent Claim
69 words
An apparatus according to claim 14, wherein said circuit includes a first switch system for switching the servo gain of said servo mechanism from the first value to the second value in response t a first signal from said control mechanism and a second switch system for switching the reciprocatory motion from a first speed to a second speed in response to a second signal from said control mechanism.
Claim 20
Dependent Claim
26 words
An apparatus according to claim 16, wherein the second value is less than the first value and the second speed is less than the first speed.
Claim 21
Dependent Claim
26 words
An apparatus according to claim 16, wherein the second value is greater than the first value and the second speed is greater than the first speed.
Claim 22
Dependent Claim
162 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output a focussing signal; a servo mechanism for adjusting focussing operation in accordance with the focussing signal output by said photodetector; driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; control mechanism for controlling the driving mechanism; and a circuit for imparting a different servo gain to said servo mechanism at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
Claim 23
Dependent Claim
162 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output a focussing signal; a servo mechanism for adjusting focussing operation in accordance with the focussing signal output by said photodetector; driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; control mechanism for controlling the driving mechanism; and a circuit for imparting a different servo gain to said servo mechanism at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
Claim 24
Dependent Claim
157 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output a focussing signal; a servo mechanism for adjusting focussing operation in accordance with the focussing signal output by said photodetector; driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; control mechanism for controlling the driving mechanism; and a circuit for imparting a different servo gain to said servo mechanism when the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 25
Dependent Claim
157 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output a focussing signal; a servo mechanism for adjusting focussing operation in accordance with the focussing signal output by said photodetector; driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; control mechanism for controlling the driving mechanism; and a circuit for imparting a different servo gain to said servo mechanism when the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 26
Dependent Claim
164 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output a tracking signal; a servo mechanism for adjusting tracking operation in accordance with the tracking signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for imparting a different servo gain to said servo mechanism at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
Claim 27
Dependent Claim
164 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output a tracking signal; a servo mechanism for adjusting tracking operation in accordance with the tracking signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for imparting a different servo gain to said servo mechanism at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
Claim 28
Dependent Claim
154 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output a tracking signal; a servo mechanism for adjusting tracking operation in accordance with the tracking signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for imparting a different servo gain to said servo mechanism when the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 29
Dependent Claim
154 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system to output a tracking signal; a servo mechanism for adjusting tracking operation in accordance with the tracking signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for imparting a different servo gain to said servo mechanism when the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 30
Dependent Claim
170 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system; a servo mechanism for controlling an operation of said first optical system in accordance with a signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for switching a servo gain of said servo mechanism from a first value to a second value at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
Claim 31
Dependent Claim
170 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system; a servo mechanism for controlling an operation of said first optical system in accordance with a signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for switching a servo gain of said servo mechanism from a first value to a second value at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
Claim 32
Dependent Claim
34 words
An apparatus according to claim 23, wherein said circuit switches the servo gain of said servo mechanism from the first value to the second value in response to a signal from said control mechanism.
Claim 33
Dependent Claim
64 words
An apparatus according to claim 23, wherein said circuit includes a first switch system for switching the servo gain of said servo mechanism from the first value to the second value in response to a first signal from said control mechanism and a second switch system for switching a direction of the reciprocatory motion in response to a second signal from said control mechanism.
Claim 34
Dependent Claim
68 words
An apparatus according to claim 23, wherein said circuit includes a first switch for switching the servo gain of said servo mechanism from the first value to the second value in response to a first signal from said control mechanism and a second switch system for switching the reciprocatory motion from a first speed to a second speed in response to a second signal from said control mechanism.
Claim 35
Dependent Claim
26 words
An apparatus according to claim 26, wherein the second value is less than the first value and the second speed is less than the first speed.
Claim 36
Dependent Claim
26 words
An apparatus according to claim 26, wherein the second value is greater than the first value and the second speed is greater than the first speed.
Claim 37
Dependent Claim
165 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system; a servo mechanism for controlling an operation of said first optical system in accordance with a signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for switching a servo gain of said servo mechanism from a first value to a second value when the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 38
Dependent Claim
165 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system; a servo mechanism for controlling an operation of said first optical system in accordance with a signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for switching a servo gain of said servo mechanism from a first value to a second value when the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 39
Dependent Claim
34 words
An apparatus according to claim 29, wherein said circuit switches the servo gain of said servo mechanism from the first value to the second value in response to a signal from said control mechanism.
Claim 40
Dependent Claim
64 words
An apparatus according to claim 29, wherein said circuit includes a first switch system for switching the servo gain of said servo mechanism from the first value to the second value in response to a first signal from said control mechanism and a second switch system for switching a direction of the reciprocatory motion in response to a second signal from said control mechanism.
Claim 41
Dependent Claim
69 words
An apparatus according to claim 29, wherein said circuit includes a first switch system for switching the servo gain of said servo mechanism from the first value to the second value in response to a first signal from said control mechanism and a second switch system for switching the reciprocatory motion from a first speed to a second speed in response to a second signal from said control mechanism.
Claim 42
Dependent Claim
26 words
An apparatus according to claim 32, wherein the second value is less than the first value and the second speed is less than the first speed.
Claim 43
Dependent Claim
26 words
An apparatus according to claim 32, wherein the second value is greater than the first value and the second speed is greater than the first speed.
Claim 44
Dependent Claim
181 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system; a servo mechanism for controlling an operation of said first optical system in accordance with a signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a circuit for switching a servo gain to be imparted to said servo mechanism from a first value to a second value at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
Claim 45
Dependent Claim
181 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system; a servo mechanism for controlling an operation of said first optical system in accordance with a signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a circuit for switching a servo gain to be imparted to said servo mechanism from a first value to a second value at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
Claim 46
Dependent Claim
168 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system; a servo mechanism for controlling an operation of said first optical system in accordance with a signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for switching a servo gain to be imparted to said servo mechanism from a first value to a second value when the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 47
Dependent Claim
168 words
An optical information recording and/or reproducing apparatus for an optical information record medium on which a plurality of linear tracks are arranged substantially in parallel, comprising: a laser light source for providing a laser light beam; a first optical system for guiding the laser light beam from said laser light source onto the record medium; a second optical system for acting on the laser light beam from the record medium; a photodetector for receiving the laser light beam acted on by said second optical system; a servo mechanism for controlling an operation of said first optical system in accordance with a signal output by said photodetector; a driving mechanism for providing relative reciprocatory motion between the record medium and the laser light beam; a control mechanism for controlling the driving mechanism; and a circuit for switching a servo gain to be imparted to said servo mechanism from a first value to a second value when the reciprocatory motion is switched from a constant speed to a variable speed.
Claim 48
Independent Claim
122 words
A method for recording and/or reproducing information by use of an optical information recording and/or reproducing apparatus for reciprocating an optical information record medium on which a plurality of tracks are arranged substantially in parallel, comprising the steps of: converging a light beam from a laser light source for forming a minute spot on the record medium; receiving the laser light beam from the record medium for use in controlling tracking and/or focussing of the spot; and switching a servo gain of a servo mechanism used for controlling the tracking and/or focussing of the spot from a first value to a second value at a predetermined time, the predetermined time occurring during a period for changing a velocity of the reciprocatory motion.
Claim 49
Independent Claim
122 words
A method for recording and/or reproducing information by use of an optical information recording and/or reproducing apparatus for reciprocating an optical information record medium on which a plurality of tracks are arranged substantially in parallel, comprising the steps of: converging a light beam from a laser light source for forming a minute spot on the record medium; receiving the laser light beam from the record medium for use in controlling tracking and/or focussing of the spot; and switching a servo gain of a servo mechanism used for controlling the tracking and/or focussing of the spot from a first value to a second value at a predetermined time, the predetermined time occurring during a period for changing a velocity of the reciprocatory motion.
Claim 50
Independent Claim
121 words
A method for recording and/or reproducing information by use of an optical information recording and/or reproducing apparatus for reciprocating an optical information record medium on which a plurality of tracks are arranged substantially in parallel, comprising the steps of: converging a light beam from a laser light source for forming a minute spot on the record medium; receiving the laser light beam from the record medium for use in controlling and/or focussing of the spot; and switching a servo gain of a servo mechanism used for controlling the tracking and/or focussing of the spot from a first value to a second value at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
Claim 51
Independent Claim
121 words
A method for recording and/or reproducing information by use of an optical information recording and/or reproducing apparatus for reciprocating an optical information record medium on which a plurality of tracks are arranged substantially in parallel, comprising the steps of: converging a light beam from a laser light source for forming a minute spot on the record medium; receiving the laser light beam from the record medium for use in controlling and/or focussing of the spot; and switching a servo gain of a servo mechanism used for controlling the tracking and/or focussing of the spot from a first value to a second value at a predetermined time, the predetermined time occurring during a period for changing a direction of the reciprocatory motion.
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