US5077718A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical information processing method and apparatus in which malfunctioning during tracking servo pull-in is prevented
Assignee: Canon Inc
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Filing: 1989-10-11
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Granted: 1991-12-31
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Expires: 2009-10-11
Abstract
Abstract An optical information processing apparatus includes a device for scanning tracks formed on an optical recording medium by a light beam, a device for moving the applied position of the light beam in a direction across the tracks, a device for detecting a tracking error signal indicative of the deviation between the applied position of the light beam and the tracks, a tracking servo device for feeding the tracking error signal back to the moving means, a switching device for selectively rendering the tracking servo device operative or inoperative, and a control device for measuring the time for which the tracking error signal exceeds a predetermined level, and switching the tracking servo device from its inoperative state to its operative state by the switching device after the aforementioned time exceeds a predetermined time.
Inventors
- 👤 Machiko Matsushita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:28
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/1055; G11B11/10556; G11B7/00; G11B7/002; G11B7/0025; G11B7/08; G11B7/085; G11B7/08505; G11B7/08517
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
127 words
An optical information processing apparatus comprising: means for scanning tracks formed on an optical recording medium by a light beam; moving for moving the applied position of said light beam in a direction across said tracks; means for detecting a tracking error signal indicative of the deviation between the applied position of said light beam and said tracks; tracking servo means for feeding said tracking error signal back to said moving means; switching means for selectively rendering said tracking servo means operative or inoperative; and control means for measuring the time for which said tracking error signal exceeds a predetermined level, and for switching said tracking servo means from its inoperative state to its operative state by said switching means after said time exceeds a predetermined time.
Claim 2
Dependent Claim
127 words
An optical information processing apparatus comprising: means for scanning tracks formed on an optical recording medium by a light beam; moving for moving the applied position of said light beam in a direction across said tracks; means for detecting a tracking error signal indicative of the deviation between the applied position of said light beam and said tracks; tracking servo means for feeding said tracking error signal back to said moving means; switching means for selectively rendering said tracking servo means operative or inoperative; and control means for measuring the time for which said tracking error signal exceeds a predetermined level, and for switching said tracking servo means from its inoperative state to its operative state by said switching means after said time exceeds a predetermined time.
Claim 3
Dependent Claim
43 words
An optical information processing apparatus according to claim 1, wherein said control means effects switching when the tracking error signal decreases to near the zero level after the time for which said tracking error signal exceeds a predetermined level exceeds the predetermined time.
Claim 4
Dependent Claim
45 words
An optical information processing apparatus according to claim 1, wherein said control means comprises comparing means for comparing said tracking error signal with said predetermined level, and time counting means for starting and stopping time counting in conformity with the output of said comparing means.
Claim 5
Dependent Claim
31 words
An optical information processing apparatus according to claim 1, further comprising means for causing a drive signal to be input to said moving means when said tracking servo means is inoperative.
Claim 6
Dependent Claim
163 words
An optical information processing apparatus comprising: a light source for emitting a light beam; an optical system for converging the light beam emitted from said light source on an optical recording medium having tracks to form a light spot; a motor for moving said light spot and said optical recording medium relative to each other along said tracks; an actuator for moving said light spot in a direction across the tracks; a detecting circuit for detecting a tracking error signal indicative of the positional relation between said light spot and said tracks; a tracking servo circuit for feeding back said tracking error signal back to said actuator; a switching circuit for selectively rendering said tracking servo circuit operative or inoperative; a control circuit for measuring the time for which said tracking error signal exceeds a predetermined level, and for switching said tracking servo circuit from its inoperative state to its operative state by said switching circuit after said time exceeds a predetermined time.
Claim 7
Dependent Claim
163 words
An optical information processing apparatus comprising: a light source for emitting a light beam; an optical system for converging the light beam emitted from said light source on an optical recording medium having tracks to form a light spot; a motor for moving said light spot and said optical recording medium relative to each other along said tracks; an actuator for moving said light spot in a direction across the tracks; a detecting circuit for detecting a tracking error signal indicative of the positional relation between said light spot and said tracks; a tracking servo circuit for feeding back said tracking error signal back to said actuator; a switching circuit for selectively rendering said tracking servo circuit operative or inoperative; a control circuit for measuring the time for which said tracking error signal exceeds a predetermined level, and for switching said tracking servo circuit from its inoperative state to its operative state by said switching circuit after said time exceeds a predetermined time.
Claim 8
Dependent Claim
43 words
An optical information processing apparatus according to claim 5, wherein said control circuit effects switching when the tracking error signal decreases to near the zero level after the time for which said tracking error signal exceeds a predetermined level exceeds the predetermined time.
Claim 9
Dependent Claim
43 words
An optical information processing apparatus according to claim 5, wherein said control circuit comprises a comparator for comparing said tracking error signal with said predetermined level, and a counter adapted to be set and reset in conformity with the output of said comparator.
Claim 10
Dependent Claim
31 words
An optical information processing apparatus according to claim 7, wherein said control circuit further comprises a second comparator for comparing said tracking error signal with a second level approximately to zero.
Claim 11
Dependent Claim
49 words
An optical information processing apparatus according to claim 8, wherein said control circuit further comprises a flip-flop for holding the high level output of said counter, and an AND gate for outputting the logic product signal of the output of said flip-flop and the output of said second comparator.
Claim 12
Dependent Claim
30 words
An optical information processing apparatus according to claim 5, further comprising a drive signal source for inputting a drive signal to said actuator during non-operation of said tracking servo circuit.
Claim 13
Dependent Claim
136 words
In an apparatus provided with means for detecting a tracking error signal and in which tracks formed on an optical recording medium are scanned by a light beam while tracking servo is effected on the basis of the signal, thereby recording and/or reproducing information, a method of switching the tracking servo from its inoperative state to its operative state comprising the steps of: moving the applied position of the light beam in a direction across the tracks; judging whether the tracking error signal exceeds a predetermined level; measuring the time for which the tracking error signal exceeds the predetermined level; judging whether the measured time has exceeded a predetermined time; and rendering the tracking servo operative when the tracking error signal decreases to near the zero level after the measured time has exceeded the predetermined time.
Claim 14
Dependent Claim
136 words
In an apparatus provided with means for detecting a tracking error signal and in which tracks formed on an optical recording medium are scanned by a light beam while tracking servo is effected on the basis of the signal, thereby recording and/or reproducing information, a method of switching the tracking servo from its inoperative state to its operative state comprising the steps of: moving the applied position of the light beam in a direction across the tracks; judging whether the tracking error signal exceeds a predetermined level; measuring the time for which the tracking error signal exceeds the predetermined level; judging whether the measured time has exceeded a predetermined time; and rendering the tracking servo operative when the tracking error signal decreases to near the zero level after the measured time has exceeded the predetermined time.
References Cited (Backward Citations)
US4912697A
Cited
US5010534A
Cited
US4730290A
Cited
US4764860A
Cited
EP0244665A2
Cited
EP0258043A2
Cited
EP0261918A2
Cited
US4982393A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-30 | 1995-07-01 | 1995-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-30 | 1999-07-01 | 1999-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-30 | 2003-07-01 | 2003-12-31 | $7700.00 | Window Closed / Lapsed |