EP0393885A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical recording and reproducing apparatus
Assignee: Mitsubishi Electric Corp
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Filing: 1990-04-05
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Granted: —
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Expires: 2010-04-05
Abstract
Abstract An optical disk recording and reproducing apparatus comprises: a light source 2, 3 for generating a parallel beam; a radially movable optical system 34 to condense the parallel beam from the light source on the disk 8, to split the beam reflected by the disk into a first and a second beam, and to spatially invert the second beam; a first split-beam detecting device 15 having two light receiving surfaces 15a, 15b which respectively receive the first beam; a second split-beam detecting device 105 having two light receiving surfaces 105a, 105b which respectively receive the second beam inverted in the movable optical system; and a control device 16, 106, 108 adapted to effect tracking control by moving the movable optical system in the radial direction of the disk in accordance with respective detection signals output from the first and second split-beam detecting devices.
Inventors
- 👤 Michihiro Itami Seisakusho Mitsubishi Tadokoro
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 20:20
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/094; G11B7/12; G11B7/13; G11B7/135; G11B7/1356; G11B7/1372
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
200 words
An optical recording and reproducing apparatus for optically recording and reproducing information on and from a disk (8), comprising: a light source (2, 3) for generating a parallel beam; a movable optical system (34) adapted to condense the parallel beam from said light source means on the disk, to receive the beam reflected by said disk, and to move in the radial direction of said disk; a split-beam detecting means (15) having two light-receiving surfaces (15a, 15b) which receive said reflected beam; and a control means (16, 106) adapted to effect tracking control by moving said movable optical system in the radial direction of said disk in accordance with detection signals output from said split-beam detecting means; characterised in that the movable optical system (34) splits the reflected beam into first and second beams, and spacially inverts the second beam; a second split-beam detecting means (105) is provided, having two light-receiving surfaces (105a, 105b) which receive the inverted second beam, the first reflected beam being received by the first split-beam detecting means (15); and the control means (16, 106) effects tracking control in accordance with the respective detection signals from the first and the second split-beam detecting means (15, 105).
Claim 2
Dependent Claim
200 words
An optical recording and reproducing apparatus for optically recording and reproducing information on and from a disk (8), comprising: a light source (2, 3) for generating a parallel beam; a movable optical system (34) adapted to condense the parallel beam from said light source means on the disk, to receive the beam reflected by said disk, and to move in the radial direction of said disk; a split-beam detecting means (15) having two light-receiving surfaces (15a, 15b) which receive said reflected beam; and a control means (16, 106) adapted to effect tracking control by moving said movable optical system in the radial direction of said disk in accordance with detection signals output from said split-beam detecting means; characterised in that the movable optical system (34) splits the reflected beam into first and second beams, and spacially inverts the second beam; a second split-beam detecting means (105) is provided, having two light-receiving surfaces (105a, 105b) which receive the inverted second beam, the first reflected beam being received by the first split-beam detecting means (15); and the control means (16, 106) effects tracking control in accordance with the respective detection signals from the first and the second split-beam detecting means (15, 105).
Claim 3
Dependent Claim
111 words
An apparatus as claimed in Claim 1, wherein said movable optical system includes a stationary rail (23), a carriage (31) which is movable along said rail, an objective lens (7) which is provided on said carriage and which faces said disk, a splitting means (100; 200) which is provided on said carriage and which is adapted to direct the parallel beam from said light source means to said objective lens, to receive the reflected light from said disk through said objective lens, and to split the reflected light into a first and a second beam, and an inverting means adapted to spatially invert said second beam obtained by said splitting means.
Claim 4
Dependent Claim
33 words
An apparatus as claimed in Claim 2, wherein said splitting means includes a prism (100) which is equipped with a beam splitting surface (101) adapted to receive the reflected light from said disk.
Claim 5
Dependent Claim
27 words
An apparatus as claimed in Claim 2 or 3, wherein said inverting means includes an inverting lens (103) arranged on the optical axis of said second beam.
Claim 6
Dependent Claim
58 words
An apparatus as claimed in Claim 2, wherein said inverting means includes a prism (200) equipped with a beam splitting surface (202) to receive said second beam and a reflecting surface or mirror (203) adapted to reflect the beam transmitted through this beam splitting surface and to cause it to impinge upon said beam splitting surface (202) again.
Claim 7
Dependent Claim
105 words
An apparatus as claimed in Claim 2, wherein said splitting means and said inverting means include a prism (200) which is equipped with a first beam splitting surface (201) adapted to receive the reflected light from said disk, a second beam splitting surface (202) arranged substantially at right angles to said first beam splitting surface and adapted to receive the light reflected by said disk and transmitted through said first beam splitting surface, and a reflecting surface or mirror (203) adapted to reflect the beam transmitted through said second beam splitting surface and to cause it to impinge upon said second beam splitting surface again.
Claim 8
Independent Claim
36 words
An apparatus as claimed in any preceding Claim, wherein said light source includes a semiconductor laser (2) and a collimating lens (3) adapted to convert a divergent beam from said semiconductor laser to a parallel beam.
Claim 9
Independent Claim
112 words
An apparatus as claimed in any preceding Claim, wherein said control means includes a first differential circuit (16) adapted to pick up the difference between the respective detection signals from the two light receiving surfaces (15a, 15b) of said first split-beam detecting means (15), a second differential circuit (106) adapted to pick up the difference between the respective detection signals from the two light receiving surfaces (105a, 105b) of said second split-beam detecting means (105), an adder (108) adapted to add together the outputs of said first and second differential circuits, and an electromagnetic driving means (22) adapted to move said movable optical system in accordanoe with the output of said adder.
Claim 10
Independent Claim
33 words
An apparatus as claimed in any preceding Claim, further comprising a focal-deviation detecting means (40) adapted to receive either said first beam or said second beam so as to detect any focal deviation.
Claim 11
Dependent Claim
22 words
Optical recording and reproducing apparatus, substantially as herein described with reference to any of figures 1 to 8d of the accompanying drawings.
Claim 12
Dependent Claim
22 words
Optical recording and reproducing apparatus, substantially as herein described with reference to any of figures 1 to 8d of the accompanying drawings.
References Cited (Backward Citations)
No citation records indexed.
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