US5146442A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for effecting at least one of tracking and servo control when an error signal passes a zero-cross point and reaches a predetermined non-zero value
Assignee: Canon Inc
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Filing: 1990-01-23
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Granted: 1992-09-08
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Expires: 2010-01-23
Abstract
Abstract In an optical information recording and/or reproducing apparatus, tracking and/or focusing error signals from relected light which are caused when a light spot is irradiated onto an optical recording medium are detected. Tracking and/or focusing servo circuits in the apparatus cause an objective lens to follow the medium on the basis of the result of the detection of the tracking and/or focusing error signals. When it is detected that the tracking and/or focusing error signals have reached a target value which is previously set to exceed a zero-cross point or a zero-cross level at the signal level, the tracking and/or focusing servo circuit is closed and the tracking and/or focusing servo is pulled in.
Inventors
- 👤 Satoshi Shikichi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:30
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0946; G11B7/002; G11B7/0033; G11B7/085; G11B7/08505; G11B7/08523; G11B7/0945
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
176 words
An optical information recording/reproducing apparatus in which a light beam from a light source is converged into a spot-like shape by an objective lens onto a recording medium to thereby effect at least one of recording of information on and reproducing of information from the recording medium by using the spot, said apparatus comprising: detecting means for detecting a tracking error signal indicative of positional deviation between the light spot and a track on the recording medium by using light reflected from the medium caused when the light spot irradiates the medium; an actuator for driving the objective lens to move the light spot relative to the track; a tracking servo circuit for controlling said actuator on the basis of the tracking error signal detected by said detecting means so as to correct the positional deviation; and a tracking servo pull-in circuit for causing said actuator to be driven while opening said tracking servo circuit and closing said tracking servo circuit when the tracking error signal passes a zero cross-point and reaches a predetermined, non-zero value.
Claim 2
Dependent Claim
176 words
An optical information recording/reproducing apparatus in which a light beam from a light source is converged into a spot-like shape by an objective lens onto a recording medium to thereby effect at least one of recording of information on and reproducing of information from the recording medium by using the spot, said apparatus comprising: detecting means for detecting a tracking error signal indicative of positional deviation between the light spot and a track on the recording medium by using light reflected from the medium caused when the light spot irradiates the medium; an actuator for driving the objective lens to move the light spot relative to the track; a tracking servo circuit for controlling said actuator on the basis of the tracking error signal detected by said detecting means so as to correct the positional deviation; and a tracking servo pull-in circuit for causing said actuator to be driven while opening said tracking servo circuit and closing said tracking servo circuit when the tracking error signal passes a zero cross-point and reaches a predetermined, non-zero value.
Claim 3
Dependent Claim
27 words
An apparatus according to claim 1, wherein the predetermined value is set to be a value between zero and a peak value of the tracking error signal.
Claim 4
Dependent Claim
24 words
An apparatus according to claim 1, wherein the predetermined value is set to be greater than an offset value of the tracking error signal.
Claim 5
Dependent Claim
178 words
An optical information recording/reproducing apparatus in which a light beam from a light source is converged into a spot-like shape by an objective lens onto a recording medium to thereby effect at least one of recording of information on and reproducing of information from the recording medium by using the light spot, said apparatus comprising: detecting means for detecting a focusing error signal indicative of focus deviation of the light spot on a recording surface of the recording medium by using light reflected from the medium when the light spot irradiates the medium; an actuator for driving the objective lens to move the light spot relative to the recording surface; a focusing servo circuit for controlling said actuator on the basis of the focusing error signal detected by said detecting means so as to correct the focus deviation; and a focusing servo pull-in circuit for causing said actuator to be driven while opening said focusing servo circuit and closing said focusing servo circuit when the focusing error signal passes a zero-cross point and reaches a predetermined, non-zero value.
Claim 6
Dependent Claim
178 words
An optical information recording/reproducing apparatus in which a light beam from a light source is converged into a spot-like shape by an objective lens onto a recording medium to thereby effect at least one of recording of information on and reproducing of information from the recording medium by using the light spot, said apparatus comprising: detecting means for detecting a focusing error signal indicative of focus deviation of the light spot on a recording surface of the recording medium by using light reflected from the medium when the light spot irradiates the medium; an actuator for driving the objective lens to move the light spot relative to the recording surface; a focusing servo circuit for controlling said actuator on the basis of the focusing error signal detected by said detecting means so as to correct the focus deviation; and a focusing servo pull-in circuit for causing said actuator to be driven while opening said focusing servo circuit and closing said focusing servo circuit when the focusing error signal passes a zero-cross point and reaches a predetermined, non-zero value.
Claim 7
Dependent Claim
27 words
An apparatus according to claim 4, wherein the predetermined value is set to be a value between zero and a peak value of the focusing error signal.
Claim 8
Dependent Claim
24 words
An apparatus according to claim 4, wherein the predetermined value is set to be greater than an offset value of the focusing error signal.
Claim 9
Independent Claim
156 words
A method of effecting at least one of optically recording information on and optically reproducing information from a recording medium by using a light spot obtained by converging a light beam from a light source by an objective lens, said method comprising: detecting a tracking error signal indicative of positional deviation between the light spot and a track on the recording medium by using light reflected from the recording medium caused when the light spot irradiates the medium; providing a tracking servo circuit for causing the light spot to follow the track on the basis of the tracking error signal detected in said detecting step; and performing tracking servo pull-in to cause the objective lens to move in a direction perpendicular to an optical axis of the objective lens while opening the tracking servo circuit and closing the tracking servo circuit when the tracking error signal passes a zero-cross point and reaches a predetermined, non-zero value.
Claim 10
Independent Claim
156 words
A method of effecting at least one of optically recording information on and optically reproducing information from a recording medium by using a light spot obtained by converging a light beam from a light source by an objective lens, said method comprising: detecting a tracking error signal indicative of positional deviation between the light spot and a track on the recording medium by using light reflected from the recording medium caused when the light spot irradiates the medium; providing a tracking servo circuit for causing the light spot to follow the track on the basis of the tracking error signal detected in said detecting step; and performing tracking servo pull-in to cause the objective lens to move in a direction perpendicular to an optical axis of the objective lens while opening the tracking servo circuit and closing the tracking servo circuit when the tracking error signal passes a zero-cross point and reaches a predetermined, non-zero value.
Claim 11
Independent Claim
164 words
A method of effecting at least one of optically recording information on and optically reproducing information from a recording medium by using a light spot obtained by converging a light beam from a light source by an objective lens, said method comprising: detecting a focusing error signal indicative of focus deviation of the light spot relative to a recording surface of the recording medium by using light reflected from the recording medium when the light spot irradiates the medium; providing a tracking servo circuit for causing the light spot to be in an in-focus state relative to the recording surface on the basis of the focusing error signal detected in said detecting step; and performing focusing servo pull-in to cause the objective lens to move in a direction parallel to an optical axis of the objective lens while opening the focusing servo circuit and closing the focusing servo circuit when the focusing error signal passes a zero-cross point and reaches a predetermined non-zero, value.
Claim 12
Independent Claim
164 words
A method of effecting at least one of optically recording information on and optically reproducing information from a recording medium by using a light spot obtained by converging a light beam from a light source by an objective lens, said method comprising: detecting a focusing error signal indicative of focus deviation of the light spot relative to a recording surface of the recording medium by using light reflected from the recording medium when the light spot irradiates the medium; providing a tracking servo circuit for causing the light spot to be in an in-focus state relative to the recording surface on the basis of the focusing error signal detected in said detecting step; and performing focusing servo pull-in to cause the objective lens to move in a direction parallel to an optical axis of the objective lens while opening the focusing servo circuit and closing the focusing servo circuit when the focusing error signal passes a zero-cross point and reaches a predetermined non-zero, value.
References Cited (Backward Citations)
US4817069A
Cited
US4975895A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-08 | 1996-03-09 | 1996-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-08 | 2000-03-09 | 2000-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-08 | 2004-03-09 | 2004-09-08 | $7700.00 | Window Closed / Lapsed |