Patent US2679442A successfully refreshed from Google Patents.
EP0057070A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical information reading apparatus
Assignee: Sony Corp
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Filing: 1982-01-15
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Granted: —
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Expires: 2002-01-15
Abstract
Abstract In an optical disc player or other apparatus in which a light beam (L) is directed through an objective lens (10) to be focused thereby at a record medium surface for optically reading information recorded in a track on the surface, the objective lens (10) has its central axis offset with respect to the longitudinal axis of a cylindrical body (16) forming part of a movable assembly (A) and through which the light beam (L) passes axially, and the cylindrical body (16) is both angularly displaceable about its longitudinal axis and axially displaceable relative to a guide bearing (21) forming part of a fixed assembly (B) to correct for tracking errors and for focusing errors, respectively. The fixed assembly (B) further includes a magnetic circuit (19) generating a magnetic field which intersects coils (14, 15a to 15d) included in the movable assembly (A) to receive focusing error and tracking error signals, respectively.
Inventors
- 👤 Katsuaki Tsurushima
- 👤 Kenji Shintani
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 20:42
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0925; G11B7/093
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
219 words
Apparatus for directing a light beam (L) onto a record medium surface for optically reading information recorded in a track on said surface, the apparatus comprising: a movable assembly (A) including a lens (10) interposed in the path of said light beam (L) and having a central axis parallel with the direction of the passage of the light beam therethrough, a lens support (11, 12, 13) extending outwardly from said lens (10), coil means (15, 15a to 15d) attached to said lens support (11, 12, 13), and a cylindrical body (16) fixed to said lens support (11, 12, 13) and having said path of the light beam (L) extending longitudinally therethrough, with the longitudinal axis of said cylindrical body (16) being offset laterally with respect to said central axis of said lens (10); and a fixed assembly (B) including a bearing (21) engaging around said cylindrical body (16) and guiding said cylindrical body (16) for at least angular displacements of said movable assembly (A) about said longitudinal axis of said cylindrical body (16), and magnetic circuit means (19) for generating a magnetic field intersecting said coil means (15, 15a to 15d) so that said angular displacements of said movable assembly (A) are effected in response to supplying of a driving current to said coil means (15, 15a to 15d).
Claim 2
Dependent Claim
219 words
Apparatus for directing a light beam (L) onto a record medium surface for optically reading information recorded in a track on said surface, the apparatus comprising: a movable assembly (A) including a lens (10) interposed in the path of said light beam (L) and having a central axis parallel with the direction of the passage of the light beam therethrough, a lens support (11, 12, 13) extending outwardly from said lens (10), coil means (15, 15a to 15d) attached to said lens support (11, 12, 13), and a cylindrical body (16) fixed to said lens support (11, 12, 13) and having said path of the light beam (L) extending longitudinally therethrough, with the longitudinal axis of said cylindrical body (16) being offset laterally with respect to said central axis of said lens (10); and a fixed assembly (B) including a bearing (21) engaging around said cylindrical body (16) and guiding said cylindrical body (16) for at least angular displacements of said movable assembly (A) about said longitudinal axis of said cylindrical body (16), and magnetic circuit means (19) for generating a magnetic field intersecting said coil means (15, 15a to 15d) so that said angular displacements of said movable assembly (A) are effected in response to supplying of a driving current to said coil means (15, 15a to 15d).
Claim 3
Dependent Claim
56 words
Apparatus according to claim 1 wherein said offset of said longitudinal axis of said cylindrical body (16) with respect to said central axis of said lens (10) is in a direction which corresponds to a direction along said track on the record medium surface so that said angular displacements are effective to correct for tracking errors.
Claim 4
Dependent Claim
104 words
Apparatus according to claim 2 wherein said lens (10) is operative to focus said light beam (L) substantially at said record medium surface, and said bearing (21) further guides said cylindrical body (16) for displacements of said movable assembly (A) in the direction of said longitudinal axis; and further comprising second coil means (14) also attached to said lens support (11, 12, 13) and located within said magnetic field so that supplying of a driving current to said second coil means (14) is effective to cause said displacements of said movable assembly (A) in said direction of the longitudinal axis for correcting focusing errors.
Claim 5
Dependent Claim
83 words
Apparatus according to claim 1 wherein said bearing (21) further guides said cylindrical body (16) for displacements of said movable assembly (A) in the direction of said longitudinal axis; and further comprising second coil means (14) also attached to said lens support (11, 12, 13) and located within said magnetic field so that displacements of said movable assembly (A) in said direction of said longitudinal axis are effected in response to the supplying of a driving current to said second coil means (14).
Claim 6
Dependent Claim
111 words
Apparatus according to claim 4 wherein said magnetic circuit means includes a ring-shaped magnet (19), an outer annular yoke (18a) extending from said magnet (19) and an inner annular yoke (18b) extending from said magnet (19) and being spaced radially inward from said outer yoke (18a) to define a gap (20) therebetween, one of said outer and inner yokes (18a, 18b) - has a cut-out (18'c) therein, an effective portion of the first-mentioned coil means (15a to 15d) is disposed on said lens support (11, 12, 13) in said gap (20), and said second coil means (14) is also disposed on said lens support (11, 12, 13) in said gap (20).
Claim 7
Dependent Claim
88 words
Apparatus according to claim 1 wherein said magnetic circuit means includes a ring-shaped magnet (19), an outer annular yoke (18a) extending from said magnet (19) and an inner annular yoke (18b) extending from said magnet (19) and being spaced radially from said outer yoke (18a) to define a gap (20) therebetween, one of said outer and inner yokes (18a, 18b) has a cut-out (18'a) therein, and said coil means (15a to 15d) has an effective portion thereof disposed on said lens support (11, 12, 13) in said gap.
Claim 8
Dependent Claim
21 words
Apparatus according to claim 6 wherein said bearing (21) is disposed against an inner surface of said inner annular yoke (18b).
Claim 9
Dependent Claim
46 words
Apparatus according to claim 7 wherein said gap (20) opens axially at one end, and said lens support (11, 12, 13) includes a cylindrical bobbin (13) extending axially into said gap (20) at said one end and having said coil means (15a to 15d) mounted thereon.
Claim 10
Dependent Claim
71 words
Apparatus according to claim 8 wherein said cut-out (18'a) includes diametrically opposed portions, and said coil means (15a to 15d) includes rectangular-shaped coils (15a to 15d) arranged around said bobbin (13) with end portions of said coils (15a to 15d) extending axially with respect to said bobbin (13) and with one of said end portions of each coil (15a to 15b) being adjacent to a respective one of said cut-outs (18'a).
Claim 11
Dependent Claim
18 words
Apparatus according to claim 9 wherein said ring-shaped magnet (19) has opposite poles facing axially in opposite directions.
Claim 12
Dependent Claim
72 words
Apparatus according to claim 10 wherein said bearing (21) further guides said cylindrical body (16) for displacements of said movable assembly (A) in the direction of said longitudinal axis; and further comprising an additional coil (14) wound around said bobbin (13) so that displacements of said movable assembly (A) in said direction of said longitudinal axis are effected in response to the supplying of a driving current to said additional coil (14).
Claim 13
Dependent Claim
110 words
Apparatus according to claim 11 wherein said record medium is in the form of a disc (R) which is rotated about the centre thereof, said track is substantially circular and concentric with said disc (R), said lens (10) has said centre axis thereof substantially normal to said surface so that said displacements in the direction of said longitudinal axis vary the focus of said light beam (L) at said surface, and said offset is in a direction tangential to said circular track so that said angular displacements are effective to vary the point of impingement of the light beam on said surface substantially in the direction transverse to said track.
References Cited (Backward Citations)
No citation records indexed.
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