US5452272A
Expired / Lapsed
US
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Magneto-optical recording and reproducing device having light interrupting forming main robe and side robe light beam portions
Assignee: Sharp Corp
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Filing: 1993-12-30
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Granted: 1995-09-19
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Expires: 2013-12-30
Abstract
Abstract A magneto-optical recording and reproducing device is provided with a magneto-optical disk for reproducing recorded information using light, a semiconductor laser, an objective lens for converging a light beam emitted from the semiconductor laser onto the magneto-optical disk and a light interrupting member for interrupting a portion of a light beam before it is incident on the objective lens. The magneto-optical disk is composed of a readout layer which is predominant in in-plane magnetization, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised and a recording layer for recording thereon information using a perpendicular magnetization. In this arrangement, since the light interrupting member is provided, a light spot can be made smaller, thereby improving a recording density. Moreover, even when temperature of the readout layer is raised due to a side robe generated by the light interrupting member, in-plane magnetization is maintained in the readout layer. Thus, interference by unwanted reproducing signals due to the side robe can be prevented, thereby improving a reproducing signal quality.
Inventors
- 👤 Yoshiteru Murakami
- 👤 Junsaku Nakajima
- 👤 Akira Takahashi
- 👤 Kenji Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:22
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10502; G11B11/10515; G11B11/10532; G11B11/10541; G11B11/10543; G11B7/00; G11B7/24; G11B7/241; G11B7/242; G11B7/243
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
150 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for producing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens so as to divide the light beam into a main robe whose light intensity distribution is made narrower and side robes formed on both sides of the main robe, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised above a predetermined temperature; and a recording layer for recording thereon information using a perpendicular magnetization.
Claim 2
Dependent Claim
150 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for producing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens so as to divide the light beam into a main robe whose light intensity distribution is made narrower and side robes formed on both sides of the main robe, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised above a predetermined temperature; and a recording layer for recording thereon information using a perpendicular magnetization.
Claim 3
Dependent Claim
29 words
The magneto-optical recording and reproducing device as set forth in claim 1, wherein said readout layer and said recording layer of said magneto-optical recording medium are laminated each other.
Claim 4
Dependent Claim
66 words
The magneto-optical recording and reproducing device as set forth in claim 2, wherein said magneto-optical recording medium further includes a substrate which has a property that light can be transmitted therethrough; and a transition occurs from in-plane magnetization to perpendicular magnetization in said readout layer formed on said substrate as temperature of said readout layer is raised by projecting a light beam from said light source.
Claim 5
Dependent Claim
94 words
The magneto-optical recording and reproducing device as set forth in claim 1, wherein said magneto-optical recording medium is a magneto-optical disk, said light interrupting member which is substantially formed in a rectangular shape interrupts a central portion of the light beam, and a lengthwise direction thereof is set along a radial direction of said magneto-optical disk, and in-plane magnetization in said readout layer is maintained in said readout layer even when temperature thereof is raised due to a side robe generated in a track direction of said magneto-optical disk by said light interrupting member.
Claim 6
Dependent Claim
31 words
The magneto-optical recording and reproducing device as set forth in claim 1, wherein said readout layer of said magneto-optical recording medium is a rare-earth transition metal alloy film made of GdFeCo.
Claim 7
Dependent Claim
168 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for producing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised; and a recording layer for recording thereon information using a perpendicular magnetization; wherein said readout layer of said magneto-optical recording medium is a rare-earth transition metal alloy film made of GdFeCo, wherein said readout layer of said magneto-optical recording medium is made of Gd X (FE 0 .82 Co 0 .18) 1 -X, where a composition rate X satisfies the following inequality: 0.19<X<0.29.
Claim 8
Dependent Claim
168 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for producing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised; and a recording layer for recording thereon information using a perpendicular magnetization; wherein said readout layer of said magneto-optical recording medium is a rare-earth transition metal alloy film made of GdFeCo, wherein said readout layer of said magneto-optical recording medium is made of Gd X (FE 0 .82 Co 0 .18) 1 -X, where a composition rate X satisfies the following inequality: 0.19<X<0.29.
Claim 9
Dependent Claim
19 words
The magneto-optical recording and reproducing device as set forth in claim 6, wherein the composition rate X is 0.26.
Claim 10
Dependent Claim
32 words
The magneto-optical recording and reproducing device as set forth in claim 1, wherein said recording layer of said magneto-optical recording medium is a rare-earth transition metal alloy thin film made of DyFeCo.
Claim 11
Dependent Claim
169 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for reproducing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised; and a recording layer for recording thereon information using a perpendicular magnetization; wherein said recording layer of said magneto-optical recording medium is a rare-earth transition metal alloy thin film made of DyFeCo, wherein DyFeCo has a composition from DYX(Fe Y Co 1 -Y) 1 -X, where a composition rate X satisfies the following inequality: 0.24<X<0.33, and a composition rate Y is selected at random.
Claim 12
Dependent Claim
169 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for reproducing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised; and a recording layer for recording thereon information using a perpendicular magnetization; wherein said recording layer of said magneto-optical recording medium is a rare-earth transition metal alloy thin film made of DyFeCo, wherein DyFeCo has a composition from DYX(Fe Y Co 1 -Y) 1 -X, where a composition rate X satisfies the following inequality: 0.24<X<0.33, and a composition rate Y is selected at random.
Claim 13
Dependent Claim
165 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for producing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised; and a recording layer for recording thereon information using a perpendicular magnetization; wherein said recording layer of said magneto-optical recording medium is a rare-earth transition metal alloy thin film made of DyFeCo, wherein said recording layer is made of Dy o .23 (FE 0 .78 Co 0 .22) 0 .77 whose Curie temperature is in a vicinity of 200° C.
Claim 14
Dependent Claim
165 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for producing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised; and a recording layer for recording thereon information using a perpendicular magnetization; wherein said recording layer of said magneto-optical recording medium is a rare-earth transition metal alloy thin film made of DyFeCo, wherein said recording layer is made of Dy o .23 (FE 0 .78 Co 0 .22) 0 .77 whose Curie temperature is in a vicinity of 200° C.
Claim 15
Dependent Claim
157 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for producing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised; and a recording layer for recording thereon information using a perpendicular magnetization; wherein said readout layer of said magneto-optical recording medium is made of Ho X (Fe Y Co 1- Y) 1- X, where a composition rate X satisfies the following inequality: 0.25<X<0.45, and a composition rate Y is selected at random.
Claim 16
Dependent Claim
157 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for producing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised; and a recording layer for recording thereon information using a perpendicular magnetization; wherein said readout layer of said magneto-optical recording medium is made of Ho X (Fe Y Co 1- Y) 1- X, where a composition rate X satisfies the following inequality: 0.25<X<0.45, and a composition rate Y is selected at random.
Claim 17
Dependent Claim
218 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for producing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised; and a recording layer for recording thereon information using a perpendicular magnetization; wherein said magneto-optical recording medium is a magneto-optical disk, said light interrupting member which is substantially formed in a rectangular shape interrupts a central portion of the light beam, and a lengthwise direction thereof is set along a radial direction of said magneto-optical disk, and in-plane magnetization in said readout layer is maintained in said readout layer even when temperature thereof is raised due to a side robe generated in a track direction of said magneto-optical disk by said light interrupting member; wherein a width of said light interrupting member is set within 0.15-0.25 times a diameter of the light beam.
Claim 18
Dependent Claim
218 words
A magneto-optical recording and reproducing device comprising: a magneto-optical recording medium for reproducing therefrom recorded information using light; a light source for producing a light beam; an objective lens for converging a light beam emitted from said light source onto said magneto-optical recording medium; and a light interrupting member for interrupting a portion of the light beam emitted from said light source before it is incident onto said objective lens, wherein said magneto-optical recording medium includes: a readout layer which is predominant in in-plane magnetization at room temperature, and in which a transition occurs to be predominant in perpendicular magnetization as temperature thereof is raised; and a recording layer for recording thereon information using a perpendicular magnetization; wherein said magneto-optical recording medium is a magneto-optical disk, said light interrupting member which is substantially formed in a rectangular shape interrupts a central portion of the light beam, and a lengthwise direction thereof is set along a radial direction of said magneto-optical disk, and in-plane magnetization in said readout layer is maintained in said readout layer even when temperature thereof is raised due to a side robe generated in a track direction of said magneto-optical disk by said light interrupting member; wherein a width of said light interrupting member is set within 0.15-0.25 times a diameter of the light beam.
Claim 19
Dependent Claim
25 words
The magneto-optical recording and reproducing device as set forth in claim 12, wherein the width is set 0.2 times the diameter of the light beam.
Claim 20
Dependent Claim
37 words
The magneto-optical recording and reproducing device as set forth in claim 1, wherein said magneto-optical recording medium is a magneto-optical disk whereon grooves for recording thereon information are formed in a peripheral direction of said magneto-optical disk.
Claim 21
Dependent Claim
37 words
The magneto-optical recording and reproducing device as set forth in claim 1, wherein said magneto-optical recording medium is a magneto-optical disk whereon lands for recording thereon information are formed in a peripheral direction of said magneto-optical disk.
Claim 22
Dependent Claim
38 words
The magneto-optical recording and reproducing device as set forth in claim 3, wherein said magneto-optical recording medium further includes a radiating film formed on said recording layer so as to confront said readout layer via said recording layer.
Claim 23
Dependent Claim
25 words
The magneto-optical recording and reproducing device as set forth in claim 16, wherein said radiating film of said magneto-optical recording medium is made of aluminum.
Claim 24
Dependent Claim
54 words
The magneto-optical recording and reproducing device as set forth in claim 1, wherein said magneto-optical recording medium is a magneto-optical disk whereon grooves are formed in a peripheral direction and lands are respectively formed between the grooves; and said readout layer and said recording layer are formed both on the grooves and the lands.
Claim 25
Dependent Claim
32 words
The magneto-optical recording and reproducing device as set forth in claim 18, wherein the grooves and the lands of said magneto-optical recording medium are formed so as to have a same width.
Claim 26
Dependent Claim
38 words
The magneto-optical recording and reproducing device as set forth in claim 18, wherein the grooves and the lands of said magneto-optical recording medium are formed in a radial direction at a pitch of 0.8 μm to 1.6 μm.
References Cited (Backward Citations)
US5278810A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-09-18 | 1999-03-20 | 1999-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-18 | 2003-03-20 | 2003-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-18 | 2007-03-20 | 2007-09-19 | $7700.00 | Window Closed / Lapsed |