Patent EP0331476A1 successfully refreshed from Google Patents.
EP0331476A1
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EP
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Magneto-optical information reproducing apparatus having a polarizing beam splitter disposed with an inclination of 45
Assignee: Canon Inc
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Filing: 1989-03-01
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Granted: —
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Expires: 2009-03-01
Abstract
Abstract A magneto-optical information reproducing apparatus comprises means (27, 24, 25) for applying a light beam polarized in a predetermined direction to a recording medium (26) on which information is magnetically recorded, first dividing means(21) for dividing the reflected or transmitted light beam from the medium modulated into a polarized state in conformity with the information by the magneto-optical effect into two light beam polarized in directions orthogonal to each other the first dividing means being disposed so that the directions of polarization of the divided two light beams form an angle of 45° with respect to the predetermined direction of polarization of the applied light beam, and detecting means (29, 30) for detecting the divided two light beams.
Inventors
- 👤 Kenichi Sasaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 06:36
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11B11/10541
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
112 words
A magneto-optical information reproducing apparatus comprising: means for applying a light beam polarized in a predetermined direction to a recording medium on which information is magnetically recorded; first dividing means for dividing the reflected or transmitted light beam from said medium modulated into a polarized state in conformity with said information by the magneto-optical effect into two light beams polarized in directions orthogonal to each other, said first dividing means being disposed so that the directions of polarization of said divided two light beams form an angle of 45° with respect to the predetermined direction of polarization of said applied light beam; and detecting means for detecting said divided two light beams.
Claim 2
Dependent Claim
112 words
A magneto-optical information reproducing apparatus comprising: means for applying a light beam polarized in a predetermined direction to a recording medium on which information is magnetically recorded; first dividing means for dividing the reflected or transmitted light beam from said medium modulated into a polarized state in conformity with said information by the magneto-optical effect into two light beams polarized in directions orthogonal to each other, said first dividing means being disposed so that the directions of polarization of said divided two light beams form an angle of 45° with respect to the predetermined direction of polarization of said applied light beam; and detecting means for detecting said divided two light beams.
Claim 3
Dependent Claim
27 words
A magneto-optical information reproducing apparatus according to Claim 1, further comprising means for differentiating the detection outputs of said divided light beams output from said detecting means.
Claim 4
Dependent Claim
19 words
A magneto-optical information reproducing apparatus according to Claim 1, wherein said first dividing means comprises a polarizing beam splitter.
Claim 5
Dependent Claim
24 words
A magneto-optical information reproducing apparatus according to Claim 3, wherein said polarizing beam splitter comprises prisms joined together and is of a cube-like shape.
Claim 6
Dependent Claim
51 words
A magneto-optical information reproducing apparatus according to Claim 4, further comprising an optical head carriage provided with at least one of two surfaces including the directions of polarization of said divided light beams and wherein said polarizing beam splitter has its outer surface held so as to bear against said surface.
Claim 7
Dependent Claim
28 words
A magneto-optical information reproducing apparatus according to Claim 5, wherein said carriage has a V-shaped mount surface bearing against the orthogonal outer surface of said polarizing beam splitter.
Claim 8
Dependent Claim
27 words
A magneto-optical information reproducing apparatus according to Claim 1, further comprising second dividing means for dividing part of the light beam before entering said first dividing means.
Claim 9
Dependent Claim
22 words
A magneto-optical information reproducing apparatus according to Claim 7, wherein said first dividing means is formed integrally with said second dividing means.
Claim 10
Dependent Claim
50 words
A magneto-optical information reproducing apparatus according to Claim 8, wherein said first and second dividing means comprise cube-shaped first and second beam splitters, respectively, said first beam splitter being rotated by 45° about the optic axis of the light beam from said medium and joined to said second beam splitter.
Claim 11
Dependent Claim
66 words
A magneto-optical information reproducing apparatus according to Claim 7, wherein said second dividing means comprises a polarizing beam splitter for increasing a polarized component in a direction orthogonal to the component of the light beam entering said second dividing means in the direction of polarization of the applied light beam to said medium, relative to the latter component, and directing it to said first dividing means.
Claim 12
Dependent Claim
36 words
A magneto-optical information reproducing apparatus according to Claim 1, further comprising second dividing means for separating the light beam reflected by said medium from said applied light beam and directing it to said first dividing means.
Claim 13
Dependent Claim
65 words
A magneto-optical information reproducing apparatus according to Claim 11, wherein said second dividing means comprises a polarizing beam splitter for increasing a polarized component in a direction orthogonal to the component of the light beam entering said second dividing means in the direction of polarization of the applied beam to said medium, relative to the latter component, and directing it to said first dividing means.
Claim 14
Dependent Claim
33 words
A magneto-optical information reproducing apparatus according to Claim 1, wherein said applying means comprises a light source and an optical system for condensing the light emitted from said light source on said medium.
Claim 15
Dependent Claim
121 words
A magneto-optical information reproducing apparatus comprising: a light source; an optical system for condensing the light beam emitted from said light source on a recording medium on which informaiton is magnetically recorded; a first polarizing beam splitter for dividing the reflected or transmitted light beam from said medium modulated into a polarized state in conformity with said information by the magneto-optical effect into two light beams polarized in directions orthogonal to each other, said first polarizing beam splitter being disposed so that the directions of polarization of said divided two light beams form an angle of 45° with respect to the predetermined direction of polarization of said applied light beam; and a detecting circuit for detecting said divided two light beams.
Claim 16
Dependent Claim
121 words
A magneto-optical information reproducing apparatus comprising: a light source; an optical system for condensing the light beam emitted from said light source on a recording medium on which informaiton is magnetically recorded; a first polarizing beam splitter for dividing the reflected or transmitted light beam from said medium modulated into a polarized state in conformity with said information by the magneto-optical effect into two light beams polarized in directions orthogonal to each other, said first polarizing beam splitter being disposed so that the directions of polarization of said divided two light beams form an angle of 45° with respect to the predetermined direction of polarization of said applied light beam; and a detecting circuit for detecting said divided two light beams.
Claim 17
Dependent Claim
28 words
A magneto-optical information reproducing apparatus according to Claim 14, further comprising a circuit for differentiating the detection outputs of said divided light beams output from said detecting circuit.
Claim 18
Dependent Claim
25 words
A magneto-optical information reproducing apparatus according to Claim 14, wherein said first polarizing beam splitter comprises prisms joined together and is of a cube-like shape.
Claim 19
Dependent Claim
52 words
A magneto-optical information reproducing apparatus according to Claim 16, further comprising an optical head carriage provided with at least one of two surfaces including the directions of polarization of said divided light beams and wherein said first polarizing beam splitter has its outer surface held so as to bear against said surface.
Claim 20
Dependent Claim
29 words
A magneto-optical information reproducing apparatus according to Claim 17, wherein said carriage has a V-shaped mount surface bearing against the orthogonal outer surface of said first polarizing beam splitter.
Claim 21
Dependent Claim
28 words
A magneto-optical information reproducing apparatus according to Claim 14, further comprising a beam splitter for dividing part of the light beam before entering said first polarizing beam splitter.
Claim 22
Dependent Claim
22 words
A magneto-optical information reproducing apparatus according to Claim 19, wherein said first polarizing beam splitter is joined integrally to said beam splitter.
Claim 23
Dependent Claim
65 words
A magneto-optical information reproducing apparatus according to Claim 19, wherein said beam splitter comprises a second polarizing beam splitter for increasing a polarized component in a direction orthogonal to the component of the light beam entering said beam splitter in the direction of polarization of the applied beam to said medium, relative to the latter component, and directing it to said first polarizing beam splitter.
Claim 24
Dependent Claim
37 words
A magneto-optical information reproducing apparatus according to Claim 14, further comprising a beam splitter for separating the light beam reflected by said medium from said applied light beam and directing it to said first polarizing beam splitter.
Claim 25
Dependent Claim
65 words
A magneto-optical information reproducing apparatus according to Claim 22, wherein said beam splitter comprises a second polarizing beam splitter for increasing a polarized component in a direction orthogonal to the component of the light beam entering said beam splitter in the direction of polarization of the applied beam to said medium, relative to the latter component, and directing it to said first polarizing beam splitter.
References Cited (Backward Citations)
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