Patent US4538254A successfully refreshed from Google Patents.
US4538254A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pickup device
Assignee: Hitachi Ltd
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Filing: 1982-09-15
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Granted: 1985-08-27
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Expires: 2002-09-15
Abstract
Abstract A pickup device for compensating for jitter by driving a scanning needle in the direction of a record track on a disc comprises a resiliently held support which supports a cantilever having the scanning needle mounted thereon and a permanent magnet mounted at an end thereof, and a driver to which a drive current is supplied to generate a magnetic field to be acted on the permanent magnet. A drive force created by the action of the magnetic field is in parallel to a surface of the disc so that the scanning needle is driven in parallel to the surface of the disc.
Inventors
- 👤 Osamu Hattori
- 👤 Shingo Tamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:33
CPC Classifications
G; G11; G11B; G11B21/00; G11B21/02; G11B21/03; G11B3/00; G11B3/02; G11B3/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
124 words
A pickup device comprising: a scanning needle having a signal detecting electrode; a cantilever having said scanning needle mounted at one end thereof and a permanent magnet mounted at the other end thereof; a support for resiliently supporting said cantilever; a jitter compensation drive coil for generating a magnetic field to be acted on said permanent magnet; a current flowing in said drive coil being varied to drive said scanning needle in the direction of a record track of a disc to compensate for jitter; said support and said permanent magnet being arranged relative to each other such that a line connecting a support point of said support and a center of said permanent magnet is in parallel to a surface of said disc.
Claim 2
Dependent Claim
124 words
A pickup device comprising: a scanning needle having a signal detecting electrode; a cantilever having said scanning needle mounted at one end thereof and a permanent magnet mounted at the other end thereof; a support for resiliently supporting said cantilever; a jitter compensation drive coil for generating a magnetic field to be acted on said permanent magnet; a current flowing in said drive coil being varied to drive said scanning needle in the direction of a record track of a disc to compensate for jitter; said support and said permanent magnet being arranged relative to each other such that a line connecting a support point of said support and a center of said permanent magnet is in parallel to a surface of said disc.
Claim 3
Dependent Claim
135 words
A pickup device comprising: a scanning needle having a signal detecting electrode; a cantilever having said scanning needle mounted at one end thereof and a permanent magnet mounted at the other end thereof; a support for resiliently supporting said cantilever; a jitter compensation drive coil for generating a magnetic field to be acted on said permanent magnet; a current flowing in said drive coil being varied to drive said scanning needle in the direction of a record track of a disc to compensate for jitter; and means for supplying a constant D.C. current to said drive coil, said support and said permanent magnet being arranged relative to each other such that a line connecting a support point of said support and a center of said permanent magnet is parallel to a surface of said disc.
Claim 4
Dependent Claim
135 words
A pickup device comprising: a scanning needle having a signal detecting electrode; a cantilever having said scanning needle mounted at one end thereof and a permanent magnet mounted at the other end thereof; a support for resiliently supporting said cantilever; a jitter compensation drive coil for generating a magnetic field to be acted on said permanent magnet; a current flowing in said drive coil being varied to drive said scanning needle in the direction of a record track of a disc to compensate for jitter; and means for supplying a constant D.C. current to said drive coil, said support and said permanent magnet being arranged relative to each other such that a line connecting a support point of said support and a center of said permanent magnet is parallel to a surface of said disc.
Claim 5
Dependent Claim
176 words
A pickup device comprising: a scanning needle having a signal detecting electrode; a cantilever having said scanning needle mounted at one end thereof and a permanent magnet mounted at the other end thereof; a support for resiliently supporting said cantilever; jitter compensation means including a jitter compensation drive coil for generating a magnetic field for acting on said permanent magnet when supplied with a drive current, and means for supplying a varying current to said drive coil to drive said scanning needle in the direction of a record track of said disc to compensate for jitter; and means for reducing a variation of pressure of said scanning needle with respect to said disc in a direction normal to a surface of said disc when the jitter compensation is applied to said scanning needle, said pressure variation reducing means including arranging said support and permanent magnet relative to each other such that a line connecting a support point of said support and a center of said permanent magnet is in parallel to the surface of said disc.
Claim 6
Dependent Claim
176 words
A pickup device comprising: a scanning needle having a signal detecting electrode; a cantilever having said scanning needle mounted at one end thereof and a permanent magnet mounted at the other end thereof; a support for resiliently supporting said cantilever; jitter compensation means including a jitter compensation drive coil for generating a magnetic field for acting on said permanent magnet when supplied with a drive current, and means for supplying a varying current to said drive coil to drive said scanning needle in the direction of a record track of said disc to compensate for jitter; and means for reducing a variation of pressure of said scanning needle with respect to said disc in a direction normal to a surface of said disc when the jitter compensation is applied to said scanning needle, said pressure variation reducing means including arranging said support and permanent magnet relative to each other such that a line connecting a support point of said support and a center of said permanent magnet is in parallel to the surface of said disc.
Claim 7
Dependent Claim
26 words
A pickup device according to claim 3, wherein said pressure variation reducing means further includes means for supplying a constant D.C. current to said drive coil.
Claim 8
Dependent Claim
42 words
A pickup device according to claim 4, wherein said drive coil is responsive to said constant D.C. current for generating a magnetic field having an attractive force acting on said permanent magnet in a direction parallel to the surface of said disc.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-08-26 | 1989-02-25 | 1989-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-26 | 1993-02-25 | 1993-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-26 | 1997-02-25 | 1997-08-27 | $7700.00 | Window Closed / Lapsed |