US5384762A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Focusing servo in an optical disk drive
Assignee: International Business Machines Corp
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Filing: 1994-02-04
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Granted: 1995-01-24
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Expires: 2014-02-04
Abstract
Abstract An optical disk drive includes a gain control for controlling the gain of a focus servo loop in response to the seek velocity of an optical head. At a low seek velocity, the focus servo gain is reduced to minimize the influence of beam scattering on the groove of an optical disk onto a focusing error signal (FES) and a tracking error signal (TES).
Inventors
- 👤 Naoyuki Kagami
- 👤 Hiroaki Kubo
- 👤 Keiichi Okada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:16
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/085; G11B7/08505; G11B7/08529; G11B7/08511; G11B7/09; G11B7/0941
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
179 words
An optical disk drive for recovering data recorded on tracks on an optical disk, the optical disk drive comprising: a laser capable of emitting an optical beam projecting onto the optical disk; means coupled to the laser for controlling a projected position of the optical beam to follow a track on the optical disk and to seek across tracks of the optical disk; means for monitoring a seek velocity of the optical beam; means for counting the number of tracks remaining to be crossed during a seek across tracks of an optical disk; and focusing means coupled to the laser for controlling the projection of the optical beam to be in a focus condition on a recording surface of the optical disk, the focusing means including a focus servo and means for adjusting a gain of the focus servo loop in response to a reduction in a seek velocity of the optical beam detected by said velocity monitoring means only when an end portion of the seek across tracks of the optical disk is detected by said counting means.
Claim 2
Dependent Claim
179 words
An optical disk drive for recovering data recorded on tracks on an optical disk, the optical disk drive comprising: a laser capable of emitting an optical beam projecting onto the optical disk; means coupled to the laser for controlling a projected position of the optical beam to follow a track on the optical disk and to seek across tracks of the optical disk; means for monitoring a seek velocity of the optical beam; means for counting the number of tracks remaining to be crossed during a seek across tracks of an optical disk; and focusing means coupled to the laser for controlling the projection of the optical beam to be in a focus condition on a recording surface of the optical disk, the focusing means including a focus servo and means for adjusting a gain of the focus servo loop in response to a reduction in a seek velocity of the optical beam detected by said velocity monitoring means only when an end portion of the seek across tracks of the optical disk is detected by said counting means.
Claim 3
Dependent Claim
44 words
The optical disk drive of claim 1 wherein the focusing means decreases the gain of the focus servo loop in response to a reduction below a predetermined value of the seek velocity of the optical beam in seeking across tracks of the optical disk.
Claim 4
Dependent Claim
194 words
An optical disk drive for recovering data recorded on tracks on an optical disk, the optical disk drive comprising: a laser capable of emitting an optical beam projecting onto the optical disk; means coupled to the laser for controlling a projected position of the optical beam to follow a track on the optical disk and to seek across tracks to a target track of the optical disk; means for counting the number of tracks remaining to be crossed during a seek across tracks of the optical disk and for comparing the track count with a predetermined track count indicative of an end portion of the seek; and focusing means coupled to the laser for controlling the projection of the optical beam to be in a focus condition on a recording surface of the optical disk, the focusing means including a focus servo and means for adjusting a gain of the focus servo loop only in response to reading the predetermined track count from said counting means indicating that the projected position of the optical beam relative to the target track has reached the end portion of the seek across tracks of the optical disk.
Claim 5
Dependent Claim
194 words
An optical disk drive for recovering data recorded on tracks on an optical disk, the optical disk drive comprising: a laser capable of emitting an optical beam projecting onto the optical disk; means coupled to the laser for controlling a projected position of the optical beam to follow a track on the optical disk and to seek across tracks to a target track of the optical disk; means for counting the number of tracks remaining to be crossed during a seek across tracks of the optical disk and for comparing the track count with a predetermined track count indicative of an end portion of the seek; and focusing means coupled to the laser for controlling the projection of the optical beam to be in a focus condition on a recording surface of the optical disk, the focusing means including a focus servo and means for adjusting a gain of the focus servo loop only in response to reading the predetermined track count from said counting means indicating that the projected position of the optical beam relative to the target track has reached the end portion of the seek across tracks of the optical disk.
Claim 6
Independent Claim
134 words
A method for focusing an optical beam on a track of an optical disk in an optical disk drive, the optical disk drive including means for emitting the optical beam projecting onto the optical disk, a focus servo and means for adjusting a gain of the focus servo loop, the method comprising: seeking across tracks of the optical disk to position the optical beam over the track; counting the number of tracks remaining to be crossed during the seek; comparing the track count with a predetermined track count indicative of an end portion of the seek; monitoring a seek velocity of the optical beam; and adjusting a gain of the focus servo loop in response to a reduction in the seek velocity of the optical beam only when the predetermined track count is reached.
Claim 7
Independent Claim
134 words
A method for focusing an optical beam on a track of an optical disk in an optical disk drive, the optical disk drive including means for emitting the optical beam projecting onto the optical disk, a focus servo and means for adjusting a gain of the focus servo loop, the method comprising: seeking across tracks of the optical disk to position the optical beam over the track; counting the number of tracks remaining to be crossed during the seek; comparing the track count with a predetermined track count indicative of an end portion of the seek; monitoring a seek velocity of the optical beam; and adjusting a gain of the focus servo loop in response to a reduction in the seek velocity of the optical beam only when the predetermined track count is reached.
Claim 8
Dependent Claim
35 words
The method of claim 4 wherein the adjusting step includes decreasing the gain of the focus servo loop in response to a reduction below a predetermined value of the seek velocity of the optical beam.
Claim 9
Independent Claim
139 words
A method for focusing an optical beam on a track of an optical disk in an optical disk drive, the optical disk drive including means for emitting the optical beam projecting onto the optical disk, a focus servo and means for adjusting a gain of the focus servo loop, the method comprising: seeking across tracks of the optical disk to position the optical beam over the target track; counting the number of tracks remaining to be crossed during the seek; comparing the track count with a predetermined track count indicating that the position of the optical beam relative to the target track has reached of an end portion of the seek across tracks; monitoring a seek velocity of the optical beam; and adjusting a gain of the focus servo loop only in response to reading the predetermined track count.
Claim 10
Independent Claim
139 words
A method for focusing an optical beam on a track of an optical disk in an optical disk drive, the optical disk drive including means for emitting the optical beam projecting onto the optical disk, a focus servo and means for adjusting a gain of the focus servo loop, the method comprising: seeking across tracks of the optical disk to position the optical beam over the target track; counting the number of tracks remaining to be crossed during the seek; comparing the track count with a predetermined track count indicating that the position of the optical beam relative to the target track has reached of an end portion of the seek across tracks; monitoring a seek velocity of the optical beam; and adjusting a gain of the focus servo loop only in response to reading the predetermined track count.
References Cited (Backward Citations)
JPS5641533A
Cited
US4497047A
Cited
JPS58128031A
Cited
US4512004A
Cited
JPS60261035A
Cited
JPS6129424A
Cited
US4890273A
Cited
US4890274A
Cited
JPS61260429A
Cited
US4701603A
Cited
US5023854A
Cited
US4888756A
Cited
JPS63119578A
Cited
JPS63241732A
Cited
JPS63298822A
Cited
US4982392A
Cited
US5121370A
Cited
JPH01290130A
Cited
US5020045A
Cited
US5038333A
Cited
JPH03118480A
Cited
US5140576A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-01-23 | 1998-07-25 | 1999-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-23 | 2002-07-25 | 2003-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-23 | 2006-07-25 | 2007-01-24 | $7700.00 | Window Closed / Lapsed |