US4512004A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for optically reproducing an information signal recorded on a record disc
Assignee: Sony Corp
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Filing: 1983-01-24
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Granted: 1985-04-16
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Expires: 2003-01-24
Abstract
Abstract An optical reproducing apparatus includes an optical pickup device which projects a laser beam onto a record disc having an information signal recorded in a plurality of record tracks thereon and which reproduces the information signal from the modulated laser beam reflected from the record disc, the optical pickup device including an objective lens movable in directions toward and away from the record disc to focus the projected laser beam onto the record disc; a focus servo control arrangement which moves the objective lens in the directions toward and away from the record disc in response to a focusing error signal which, in turn, is produced in response to the modulated laser beam, so as to focus the projected laser beam onto the record disc; a laser beam tracking device which rapidly moves the laser beam projected onto the record disc, during a search mode of operation, in a direction transverse to the record tracks to a desired position with respect to the record disc; a track jump signal generating circuit which produces a track jump signal in response to a track jump command signal to control the laser beam tracking device to rapidly move the projected laser beam to the desired position; and a current divider circuit which reduces the level of the focusing error signal, at least during the duration of the track jump signal, in response to the track jump command signal.
Inventors
- 👤 Chiaki Nonaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:47
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/085; G11B7/09; G11B7/0901; G11B7/095
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
169 words
Apparatus for reproducing an information signal recorded in at least one record track on a record disc, comprising: optical pickup means for projecting a light beam onto said record disc to be modulated by said information signal recorded therein and for reproducing said information signal in response to said modulated light beam, said optical pickup means including lens means for focusing said projected light beam onto said record disc; focus control means for moving said lens means in response to a focusing error signal produced in response to said modulated light beam so as to focus said projected light beam onto said record disc; light beam tracking means for rapidly moving said light beam projected onto said record disc in a direction transverse to said at least one record track to a desired position with respect to said record disc, in response to a track jump command signal; and gain control means for reducing the level of said focusing error signal in response to said track jump command signal.
Claim 2
Dependent Claim
169 words
Apparatus for reproducing an information signal recorded in at least one record track on a record disc, comprising: optical pickup means for projecting a light beam onto said record disc to be modulated by said information signal recorded therein and for reproducing said information signal in response to said modulated light beam, said optical pickup means including lens means for focusing said projected light beam onto said record disc; focus control means for moving said lens means in response to a focusing error signal produced in response to said modulated light beam so as to focus said projected light beam onto said record disc; light beam tracking means for rapidly moving said light beam projected onto said record disc in a direction transverse to said at least one record track to a desired position with respect to said record disc, in response to a track jump command signal; and gain control means for reducing the level of said focusing error signal in response to said track jump command signal.
Claim 3
Dependent Claim
86 words
Apparatus according to claim 1; in which said light beam tracking means includes optical reflecting means for moving said light beam projected onto said record disc in said direction transverse to said at least one record track and driving means for controlling said optical reflecting means to rapidly move said light beam projected onto said record disc in said direction transverse to said at least one record track to said desired position with respect to said record disc, in response to said track jump command signal.
Claim 4
Dependent Claim
62 words
Apparatus according to claim 1; further including track jump signal generating means for producing a track jump signal, comprising a drive pulse signal followed by a brake pulse signal, in response to said track jump command signal; and in which said gain control means reduces the level of said focusing error signal at least during the duration of said track jump signal.
Claim 5
Dependent Claim
80 words
Apparatus according to claim 3; in which said track jump signal generating means includes first multivibrator means for producing said drive pulse signal having a first polarity, in response to said track jump command signal, second multivibrator means for producing said brake pulse signal having a second polarity opposite to said first polarity in response to said drive signal signal, and combining means for combining said drive pulse signal and said brake pulse signal to form said track jump signal.
Claim 6
Dependent Claim
95 words
Apparatus according to claim 4; in which said second multivibrator means further produces a third pulse signal following said drive pulse signal, said third pulse signal having a duration at least equal to the duration of said brake pulse signal and having said first polarity, and in which said gain control means includes gain reduction means for reducing the level of said focusing error signal and control means for controlling said gain reduction means to reduce the level of said focusing error signal in response to said drive pulse signal and said third pulse signal.
Claim 7
Dependent Claim
95 words
Apparatus according to claim 5; in which said gain reduction means includes current divider means adapted to be connected to said focus control means for reducing the gain of said focusing error signal supplied thereto, and said gain control means further includes switch control means for producing a switch control signal in response to said drive pulse signal and said third pulse signal and switch means for connecting said current divider means to said focus control means in response to said switch control signal so as to reduce the level of said focusing error signal.
Claim 8
Dependent Claim
38 words
Apparatus according to claim 6; in which said switch control means includes OR gate means having first and second inputs supplied with said drive pulse signal and said third pulse signal, respectively, to produce said switch control signal.
Claim 9
Dependent Claim
79 words
Apparatus according to claim 1; in which said gain control means includes first multivibrator means for producing a first pulse signal having a first polarity, in response to said track jump command signal, second multivibrator means for producing a second pulse signal following said first pulse signal and having said first polarity, in response to said drive pulse signal, and combining means for combining said first pulse signal and said second pulse signal to form a switch control signal.
Claim 10
Dependent Claim
49 words
Apparatus according to claim 8; in which said gain control means includes gain reduction means for reducing the level of said focusing error signal and control means for controlling said gain reduction means to reduce the level of said focusing error signal in response to said switch control signal.
Claim 11
Dependent Claim
71 words
Apparatus according to claim 9; in which said gain reduction means includes current divider means adapted to be connected to said focus control means for reducing the level of said focusing error signal supplied thereto, and said gain control means further includes switch means for connecting said current divider means to said focus control means in response to said switch control signal to reduce the level of said focusing error signal.
Claim 12
Dependent Claim
37 words
Apparatus according to claim 8; in which said combining means includes OR gate means having first and second inputs supplied with said first pulse signal and said second pulse signal, respectively, to produce said switch control signal.
References Cited (Backward Citations)
US4163149A
Cited
US4243848A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-04-15 | 1988-10-15 | 1989-04-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-15 | 1992-10-15 | 1993-04-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-15 | 1996-10-15 | 1997-04-16 | $7700.00 | Window Closed / Lapsed |