Patent EP0338864A2 successfully refreshed from Google Patents.
EP0338864A2
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Magneto-optical playback heads
Assignee: Sony Corp
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Filing: 1989-04-21
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Granted: —
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Expires: 2009-04-21
Abstract
Abstract A magnetic-optical playback head comprises a first optical waveguide (38) facing a light source (36) at one end thereof and facing a magneto-optical recording medium (31) at other end thereof for guiding an incident light beam to the recording medium (31), a second optical waveguide (40) for guiding a light beam reflected from the recording medium (31) to a photodetector (37) provided at one end thereof, a polarizer (46) for the first optical waveguide (38), and an analyzer (47) for the second optical waveguide (40), the polarizer (46) and the analyzer (47) being formed by providing first and second conductive layers (50, 51) on the first and second optical waveguides (38, 40), with first and second insulating buffer layers (48, 49) interposed therebetween.
Inventors
- 👤 Teiichi C/O Patents Division Miyauchi
- 👤 Yutaka C/O Patents Division Soda
- 👤 Tetsuo C/O Patents Division Sekiya
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 20:24
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11B11/10541; G11B11/10543; G11B11/10545; G11B11/1055; G11B11/10552; G11B11/10554; G11B11/1058; G11B5/00; G11B5/127; G11B5/31; G11B5/3109; G11B5/313; G11B5/3163; G11B5/48; G11B5/58; G11B5/60; G11B5/6005; G11B7/00; G11B7/12; G11B7/122; G11B7/123; G11B7/124
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
124 words
A magneto-optical playback head comprising: a first optical waveguide (38) facing a light source (36) at one end thereof and facing a magneto-optical recording medium (31) at another end thereof for guiding an incident light beam to said recording medium (31); a second optical waveguide (40) for guiding a light beam reflected from said recording medium (31) to a photodetector (33) provided at one end thereof; a polarizer (46) for said first optical waveguide (38); and an analyzer (47) for said second optical waveguide (40), said polarizer (46) and said analyzer (47) being formed by providing first and second conductive layers (50, 51) on said first and second optical waveguides (38, 40), with first and second insulating buffer layers (48, 49) interposed therebetween, respectively.
Claim 2
Dependent Claim
124 words
A magneto-optical playback head comprising: a first optical waveguide (38) facing a light source (36) at one end thereof and facing a magneto-optical recording medium (31) at another end thereof for guiding an incident light beam to said recording medium (31); a second optical waveguide (40) for guiding a light beam reflected from said recording medium (31) to a photodetector (33) provided at one end thereof; a polarizer (46) for said first optical waveguide (38); and an analyzer (47) for said second optical waveguide (40), said polarizer (46) and said analyzer (47) being formed by providing first and second conductive layers (50, 51) on said first and second optical waveguides (38, 40), with first and second insulating buffer layers (48, 49) interposed therebetween, respectively.
Claim 3
Dependent Claim
27 words
A magneto-optical playback head according to claim 1 wherein said first and said second conductive layers (50, 51) are arranged at a predetermined angle with each other.
Claim 4
Dependent Claim
15 words
A magneto-optical playback head according to claim 2 wherein said predetermined angle is substantially 45°.
Claim 5
Dependent Claim
49 words
A magneto-optical playback head according to claim 1 wherein said second optical waveguide (40) is arranged to face said recording medium (31) at the other end thereof, aligned to substantially the same portion of said recording medium (31) as that to which said first optical waveguide (38) is aligned.
Claim 6
Dependent Claim
37 words
A magneto-optical playback head according to claim 4 wherein said second optical waveguide (40) has an opening at said other end which is larger than an opening at said other end of said first optical waveguide (38).
Claim 7
Dependent Claim
32 words
A magneto-optical playback head according to claim 1 wherein said first and second optical waveguides (38, 40) are formed into a common structure at said other ends facing said recording medium (31).
Claim 8
Dependent Claim
19 words
A magneto-optical playback head according to claim 1 wherein said conductive layers (50, 51 ) are formed of aluminium.
Claim 9
Dependent Claim
20 words
A magneto-optical playback head according to claim 1 wherein said conductive layers (50, 51 ) are formed of amorphous silicon.
Claim 10
Dependent Claim
25 words
A magneto-optical playback head according to claim 1 wherein said first and second optical waveguides (38, 40) are coupled optically by a directional coupler (39).
Claim 11
Dependent Claim
166 words
A magneto-optical playback head comprising: a first optical waveguide (121A) coupled to a light source (118) at one end thereof and facing a magneto-optical recording medium (31) at another end thereof for guiding an incident light beam to said recording medium (31); a second optical waveguide (121 B) for guiding a reflected light beam from said recording medium (31), said second optical waveguide (121 B) being formed of a first waveguide portion (121B1) and a second waveguide portion (121B2), and one end of each of said first and second waveguide portions (121B1, 121 B2) being provided with respective first and second photodetectors (119, 120), respectively; a polarizer (123) for said first optical waveguide (121A); and first and second analyzers (124, 125) for said first and second waveguide portions (121B1, 121B2) formed by providing first, second, and third conductive layers (129, 130, 131) on said first optical waveguide (121A) and said first and second waveguide portions (121B1, 121B2), respectively, with insulating buffer layers (126, 127,128) interposed therebetween.
Claim 12
Dependent Claim
166 words
A magneto-optical playback head comprising: a first optical waveguide (121A) coupled to a light source (118) at one end thereof and facing a magneto-optical recording medium (31) at another end thereof for guiding an incident light beam to said recording medium (31); a second optical waveguide (121 B) for guiding a reflected light beam from said recording medium (31), said second optical waveguide (121 B) being formed of a first waveguide portion (121B1) and a second waveguide portion (121B2), and one end of each of said first and second waveguide portions (121B1, 121 B2) being provided with respective first and second photodetectors (119, 120), respectively; a polarizer (123) for said first optical waveguide (121A); and first and second analyzers (124, 125) for said first and second waveguide portions (121B1, 121B2) formed by providing first, second, and third conductive layers (129, 130, 131) on said first optical waveguide (121A) and said first and second waveguide portions (121B1, 121B2), respectively, with insulating buffer layers (126, 127,128) interposed therebetween.
Claim 13
Dependent Claim
23 words
A magneto-optical playback head according to claim 10 wherein an output signal is derived from said first and second photodetectors (119, 120) differentially.
Claim 14
Dependent Claim
55 words
A magneto-optical playback head according to claim 10 wherein said second conductive layer (130) of said first analyzer (124) and said third conductive layer (131) of said second analyzer (125) are inclined at first and second angles, respectively, with respect to a reference plane defined by said first conductive layer (129) of said polarizer (123).
Claim 15
Dependent Claim
31 words
A magneto-optical playback head according to claim 10 wherein said polarizer (123), and said analyzers (124, 125) each operate as a TE mode pass filter or a TM mode pass filter.
Claim 16
Dependent Claim
22 words
A magneto-optical playback head according to claim 13 wherein said first and second analyzers (124, 125) operate as TE mode pass filters.
Claim 17
Dependent Claim
53 words
A magneto-optical playback head according to claim 14 wherein optical outputs of light beams to be detected at said first and second photodetectors (119, 120) change oppositely to each other when light beams having the same change in the rotation angle of polarization are passed through said first and second analyzers (124, 125).
Claim 18
Dependent Claim
53 words
A magnetic recording and magneto-optical playback head comprising: a magneto-optical playback head according to any one of claims 1 to 15; and a thin-film magnetic recording head (222) disposed adjacent to said magneto-optical playback head, said thin-film magnetic recording head (222) and said magneto-optical playback head being provided on a common substrate (221).
Claim 19
Dependent Claim
21 words
A magnetic recording and magnetic-optical playback head according to claim 16 wherein said heads are formed on a common slider (276).
Claim 20
Dependent Claim
50 words
A magnetic-optical playback head according to claim 1 or claim 10 wherein said first optical waveguide (38, 121A) forms an elliptical spot on said recording medium (31) such that the larger diameter of said elliptical spot is aligned with the width of a recording track on said recording medium (31).
Claim 21
Dependent Claim
31 words
A magneto-optical playback head according to claim 10 wherein said first and second waveguide portions (l2lBl, 121B2) are arranged to be partially parallel to a surface of said recording medium (31).
Claim 22
Dependent Claim
37 words
A magneto-optical playback head according to claim 10 wherein said first and second waveguide portions (121 B1,121 B2) are bent to bring said waveguide portions (121B1, 121B2) substantially parallel to a surface of said recording medium (31).
References Cited (Backward Citations)
No citation records indexed.
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