US4408311A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical tracking apparatus
Assignee: Sony Corp
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Filing: 1981-05-07
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Granted: 1983-10-04
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Expires: 2001-05-07
Abstract
Abstract An optical tracking apparatus for tracing a spiral track on a recording disk includes an optical pickup device having a semiconductor laser and a photoelectric conversion element; an arm device pivotally mounted to an arm shaft with the pickup device being mounted to the free end thereof to thereby move substantially along the radial direction of the recording disk; sectorial arm drive coil attached to a rear end portion of the arm device and having a current path loop in parallel with the rotational plane of the arm device; and a pair of stationary magnetic field forming devices, each formed of a respective yoke and permanent magnet assembly, the yokes having respective air gaps in which magnetic fields in opposite directions to each other are formed, the arm drive coil being arranged to move in the air gaps and being supplied with an arm drive signal and a tracking error correction signal for causing the pickup device to trace the track.
Inventors
- 👤 Junichi Suzuki
- 👤 Kenji Shintani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:23
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/085; G11B7/0857; G11B7/08576; G11B7/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
240 words
An optical tracking apparatus for tracing at least one track on a recording disk to reproduce an information signal recorded in said at least one track, comprising: optical pickup means having light-emitting means for projecting a light beam onto said recording disk to modulate said light beam with said information signal and photoelectric conversion means for producing said information signal in response to said modulated light beam; arm means pivotally mounted to an arm shaft so as to be adapted to rotate in a first plane and having a first and a second end, said pickup means being mounted to said first end so as to be adapted to move substantially along the radial direction of said recording disk; arm drive coil means attached to said second end of said arm means and having a current path loop in parallel with the first rotational plane of said arm means; means for producing an arm drive signal; means for producing a tracking error correction signal in response to said modulated light beam; and stationary magnetic field forming means having at least one pair of air gaps in which magnetic fields in opposite directions to each other are formed, said arm drive coil means being arranged to move in said at least one pair of air gaps and being supplied with said arm drive signal and said tracking error correction signal for causing said pickup means to trace at least one track.
Claim 2
Dependent Claim
240 words
An optical tracking apparatus for tracing at least one track on a recording disk to reproduce an information signal recorded in said at least one track, comprising: optical pickup means having light-emitting means for projecting a light beam onto said recording disk to modulate said light beam with said information signal and photoelectric conversion means for producing said information signal in response to said modulated light beam; arm means pivotally mounted to an arm shaft so as to be adapted to rotate in a first plane and having a first and a second end, said pickup means being mounted to said first end so as to be adapted to move substantially along the radial direction of said recording disk; arm drive coil means attached to said second end of said arm means and having a current path loop in parallel with the first rotational plane of said arm means; means for producing an arm drive signal; means for producing a tracking error correction signal in response to said modulated light beam; and stationary magnetic field forming means having at least one pair of air gaps in which magnetic fields in opposite directions to each other are formed, said arm drive coil means being arranged to move in said at least one pair of air gaps and being supplied with said arm drive signal and said tracking error correction signal for causing said pickup means to trace at least one track.
Claim 3
Dependent Claim
39 words
An optical tracking apparatus according to claim 1, in which said arm drive coil means is in the form of a sector including a pair of radial side portions arranged in said at least one pair of air gaps.
Claim 4
Dependent Claim
21 words
An optical tracking apparatus according to claim 2, in which said pair of radial side portions face toward said arm shaft.
Claim 5
Dependent Claim
47 words
An optical tracking apparatus according to claim 1, in which said magnetic field forming means has magnetic flux path loops interlinked with the current path loop of said arm drive coil means, and said magnetic flux path loops include said at least one pair of air gaps.
Claim 6
Dependent Claim
51 words
An optical tracking apparatus according to claim 1, in which said magnetic field forming means includes at least one yoke of a generally C-shaped cross section and at least one permanent magnet fixed to said at least one yoke, said at least one permanent magnet facing said arm drive coil means.
Claim 7
Dependent Claim
43 words
An optical tracking apparatus according to claim 1, in which said magnetic field forming means includes two yoke members and a permanent magnet connecting said two yoke members, said arm drive coil means being arranged between pole faces of said two yoke members.
Claim 8
Dependent Claim
26 words
An optical tracking apparatus according to claim 2, in which said arm drive coil means includes plural piled printed boards separating a plurality of drive coils.
Claim 9
Dependent Claim
17 words
An optical tracking apparatus according to claim 1, in which said light-emitting means includes a semi-conductor laser.
References Cited (Backward Citations)
US4004081A
Cited
US4214757A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-03 | 1987-04-04 | 1987-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-03 | 1991-04-04 | 1991-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-03 | 1995-04-04 | 1995-10-04 | $7700.00 | Window Closed / Lapsed |