EP0393652A2 — Magneto-optical recording and reproducing method,…

Claim 1

Independent Claim 81 words

An information recording and reproducing method comprising the steps of: applying a magnetic field (Fig. 2C) of a polarity corresponding to information (Fig. 2A) to be recorded while a recording spot (SP2; SP2′) of a high energy is irradiated to a magneto-optical recording medium (1) to record domains (106) representing the information along a track; and reading out the domains by a reproducing spot (SP1) having a lower energy than the recording spot and a high resolution power along the track.

Claim 2

Dependent Claim 81 words

An information recording and reproducing method comprising the steps of: applying a magnetic field (Fig. 2C) of a polarity corresponding to information (Fig. 2A) to be recorded while a recording spot (SP2; SP2′) of a high energy is irradiated to a magneto-optical recording medium (1) to record domains (106) representing the information along a track; and reading out the domains by a reproducing spot (SP1) having a lower energy than the recording spot and a high resolution power along the track.

Claim 3

Dependent Claim 90 words

An information recording and reproducing method comprising the steps of: applying a magnetic field (Fig. 2C) while a recording spot (SP2; SP2′; SP1) having a high energy is irradiated to a magneto-optical recording media (1) and switching a polarity of the magnetic field in accordance with information (Fig. 2A) to be recorded to record domains (106) representing the information along a track; and reading out the domains by a reproducing spot (SP1) having a low energy emitted from a laser beam having a wavelength of not greater than 600 nm.

Claim 4

Dependent Claim 90 words

An information recording and reproducing method comprising the steps of: applying a magnetic field (Fig. 2C) while a recording spot (SP2; SP2′; SP1) having a high energy is irradiated to a magneto-optical recording media (1) and switching a polarity of the magnetic field in accordance with information (Fig. 2A) to be recorded to record domains (106) representing the information along a track; and reading out the domains by a reproducing spot (SP1) having a low energy emitted from a laser beam having a wavelength of not greater than 600 nm.

Claim 5

Dependent Claim 30 words

An information recording and reproducing method according to Claim 1 wherein the reproducing spot (SP1) is formed by a laser beam having a wavelength of not longer than 600 nm.

Claim 6

Dependent Claim 32 words

An information recording and reproducing method according to Claims 2 or 3 wherein the recording spot (SP2) is formed by a laser beam having a wavelength of not shorter than 600 nm.

Claim 7

Dependent Claim 40 words

An information recording and reproducing method according to any one of Claims 2 and 4 wherein the reproducing spot (SP1) is formed by a second harmonics emitted from a semiconductor laser having a wavelength of 830 nm. (See Fig. 15)

Claim 8

Dependent Claim 45 words

An information recording and reproducing method according to any one of Claims 1 to 4 wherein a shape of at least one of the recording spot (SP2; SP2′) and the reproducing spot (SP1) extends perpendicularly to the track. (See Figs. 16A, 20, 21 and 24)

Claim 9

Dependent Claim 56 words

An information recording and reproducing method according to any one of Claims 1 to 6 wherein the recording spot (SP2; SP2′) and the reproducing spot (SP1) are irradiated through one objective lens (5), and a focusing signal and a tracking signal are detected from a reflected light of the recording spot (SP2; SP2′). (See Fig. 12A)

Claim 10

Dependent Claim 61 words

An information recording and reproducing method according to any one of Claims 1 to 7 wherein the recording spot (SP2; SP2′) and the reproducing spot (SP1) are irradiated through separate objective lenses (29, 57), and a focusing signal and a tracking signal are detected from reflected lights of the recording spot and the reproducing spot, respectively. (See Figs. 14 and 15)

Claim 11

Dependent Claim 91 words

An information recording and reproducing method according to Claim 8 wherein a shape of the reproducing spot (SP1) extends perpendicularly to the track, an optical depth of a guide groove (110) formed in the magneto-optical recording medium (1) is selected such that an amplitude of a tracking signal by the recording spot (SP2) and an amplitude of a tracking signal by the reproducing spot (SP1) are substantially equal to permit the following of the guide groove by the recording spot (SP2) and the reproducing spot (SP1). (See Figs. 16A and 17)

Claim 12

Dependent Claim 89 words

An information recording and reproducing method according to Claim 8 wherein the three spots (SP1, SUB SP) are irradiated through as objective lens (57) for irradiating the reproducing spot, a middle spot (SP1) is used as the reproducing spot and the end spots (SUB SP) are used to detect a tracking signal, and an optical depth of a guide groove (110) formed in the magneto-optical recording medium (1) is set such that an amplitude of the tracking signal by the recording spot (SP2) is substantially maximum. (See Fig. 16B)

Claim 13

Dependent Claim 62 words

An information recording and reproducing method according to any one of Claims 8 to 10 wherein an optical depth of pits (112) formed in the magneto-optical recording medium (1) is set such that an amplitude of a reproduced signal by the recording spot (SP2) and an amplitude of a reproduced signal by the reproducing spot (SP1) are substantially equal. (See Fig. 18)

Claim 14

Dependent Claim 47 words

An information recording and reproducing method according to any one of Claims 1 to 11 wherein a multi-layer recording film having a number of metal layers (502, 503; 508, 509; 511) and dielectric layers (504; 510; 512) alternately laminated is used. (See Figs. 25, 28, and 30)

Claim 15

Dependent Claim 48 words

An information recording and reproducing method according to Claim 12 wherein said metal layer consists of at least one material layer (502; 508) selected from Pt, Pd, Rh and Au and at least one material layer (503; 509) selected from Co and Fe. (See Figs. 25 and 28)

Claim 16

Dependent Claim 45 words

An information recording and reproducing method according to Claim 12 wherein said metal layer is an alloy layer (511) of at least one element selected from Pt, Pd, Rh, Ca and Au and at least one element selected from Co and Fe. (See Fig. 30)

Claim 17

Dependent Claim 38 words

An information recording and reproducing method according to any one of Claims 12 to 14 wherein a light reflection layer (505) is formed on a lowermost or uppermost layer of the multi-layer structure. (See Figs. 25, 28, 30)

Claim 18

Dependent Claim 157 words

A magneto-optical memory apparatus comprising: a motor (18) for movably carrying a magneto-optical recording medium (1); a recording head (11, 12; 200, 12) having an optical system (5; 29) for irradiating a recording spot (SP2; SP2′) having a high energy to said magneto-optical recording medium (1) and a magnetic head (12) for applying a magnetic field (Fig. 2C) of a polarity corresponding to information (Fig. 2A) to be recorded to an irradiation area of said recording spot, for recording domains (106) representing the information along a track; and a reproducing head (11; 300) having an optical system (5; 57) for irradiating a reproducing spot (SP1) having a lower energy than said recording spot and a high resolution power along the track to said magneto-optical recording medium (1) and a magneto-optical signal detection system (8) for detecting a displacement of a polarization plane of a reflected light of the reproducing spot (SP1) to read out the recorded domains(106).

Claim 19

Dependent Claim 157 words

A magneto-optical memory apparatus comprising: a motor (18) for movably carrying a magneto-optical recording medium (1); a recording head (11, 12; 200, 12) having an optical system (5; 29) for irradiating a recording spot (SP2; SP2′) having a high energy to said magneto-optical recording medium (1) and a magnetic head (12) for applying a magnetic field (Fig. 2C) of a polarity corresponding to information (Fig. 2A) to be recorded to an irradiation area of said recording spot, for recording domains (106) representing the information along a track; and a reproducing head (11; 300) having an optical system (5; 57) for irradiating a reproducing spot (SP1) having a lower energy than said recording spot and a high resolution power along the track to said magneto-optical recording medium (1) and a magneto-optical signal detection system (8) for detecting a displacement of a polarization plane of a reflected light of the reproducing spot (SP1) to read out the recorded domains(106).

Claim 20

Dependent Claim 161 words

A magneto-optical memory apparatus comprising: a motor (18) for movably carrying a magneto-optical recording medium (1); a recording head (11, 12; 200, 12) having an optical system (5; 29) for irradiating a recording spot (SP2; SP2′) having a high energy to said magneto-optical recording medium (1) and a magnetic head (12) for applying magnetic field (Fig. 2C) having a polarity thereof switched in accordance with information (Fig. 12A) to be recorded, to an irradiation area of the recording spot for recording domains (106) representing the information along a track; and a reproducing head (11; 300) having an optical system (5; 57) for irradiating a reproducing spot (SP1) having a low energy emitted by a laser beam having a wavelength of not larger than 600 nm to said magneto-optical recording medium and a magneto-optical signal detection system (8) for detecting a displacement of a polarization plane of a reflected light of the reproducing spot (SP1) to read out to recorded domains (106).

Claim 21

Dependent Claim 161 words

A magneto-optical memory apparatus comprising: a motor (18) for movably carrying a magneto-optical recording medium (1); a recording head (11, 12; 200, 12) having an optical system (5; 29) for irradiating a recording spot (SP2; SP2′) having a high energy to said magneto-optical recording medium (1) and a magnetic head (12) for applying magnetic field (Fig. 2C) having a polarity thereof switched in accordance with information (Fig. 12A) to be recorded, to an irradiation area of the recording spot for recording domains (106) representing the information along a track; and a reproducing head (11; 300) having an optical system (5; 57) for irradiating a reproducing spot (SP1) having a low energy emitted by a laser beam having a wavelength of not larger than 600 nm to said magneto-optical recording medium and a magneto-optical signal detection system (8) for detecting a displacement of a polarization plane of a reflected light of the reproducing spot (SP1) to read out to recorded domains (106).

Claim 22

Dependent Claim 29 words

A magneto-optical memory apparatus according to Claim 16 wherein said reproducing head forms the reproducing spot by a laser beam having a wavelength of not longer than 600 nm.

Claim 23

Dependent Claim 31 words

A magneto-optical memory apparatus according to Claims 17 or 18 wherein said recording head forms the recording spot by a laser beam having a wavelength of not shorter than 600 nm.

Claim 24

Dependent Claim 36 words

A magneto-optical memory apparatus according to any one of Claims 16 to 19 wherein said reproducing head forms the reproducing spot by a second harmonics generated by a second harmonics generating element from a laser source.

Claim 25

Dependent Claim 33 words

A magneto-optical memory apparatus according to any one of Claims 16 to 20 wherein a shape of at least one of the recording spot and the reproducing spot extends perpendicularly to the track.

Claim 26

Dependent Claim 66 words

A magneto-optical memory apparatus according to any one of Claims 16 to 21 wherein an optical system is shared by said recording head and said reproducing head, the recording spot and the reproducing spot are irradiated through said optical system, and said recording head includes a control signal detector for detecting a focusing signal and a tracking signal from a reflected light of the recording spot.

Claim 27

Dependent Claim 55 words

A magneto-optical memory apparatus according to Claims 16 to 21 wherein the recording spot and the reproducing spot are irradiated through separate optical system, and said recording head and said reproducing head have detectors for detecting a focusing signal and a tracking signal from reflected lights of the recording spot and the reproducing spot, respectively.

Claim 28

Dependent Claim 77 words

A magneto-optical memory apparatus according to Claim 23 wherein a shape of the reproducing spot extends perpendicularly to the track, an optical depth of a guide groove formed in the magneto-optical recording medium is selected such that an amplitude of a tracking signal by the recording spot and an amplitude of a tracking signal by the reproducing spot are substantially equal to permit the tracing of the guide groove by the recording spot and the reproducing spot.

Claim 29

Dependent Claim 74 words

A magneto-optical memory apparatus according to Claim 23 wherein the three spots are irradiated through the optical system for irradiating the reproducing spot, a middle spot is used as the reproducing spot and the end spots are used to detect a tracking signal, and an optical depth of a guide groove formed in the magneto-optical recording medium is set such that an amplitude of the tracking signal by the recording spot is substantially maximum.

Claim 30

Dependent Claim 54 words

A magneto-optical memory apparatus according to any one of Claims 23 to 25 wherein an optical depth of pits formed in the magneto-optical recording medium is set such that an amplitude of a reproduced signal by the re cording spot and an amplitude of a reproduced signal by the reproducing spot are substantially equal.

Claim 31

Dependent Claim 31 words

A magneto-optical memory apparatus according to any one of Claims 16 to 26 wherein a multi-layer recording film having a number of metal layers and dielectric layers alternately laminated is used.

Claim 32

Dependent Claim 37 words

A magneto-optical memory apparatus according to Claim 27 wherein said metal layer consists of at least one material layer selected from Pt, Pd, Rh and Au and at least one material layer selected from Co and Fe.

Claim 33

Dependent Claim 39 words

A magneto-optical memory apparatus according to Claim 27 wherein said metal layer is an alloy layer of at least one element selected from Pt, Pd, Rh, Ca and Au and at least one element selected from Co and Fe.

Claim 34

Dependent Claim 30 words

A magneto-optical memory apparatus according to any one of Claims 27 to 29 wherein a light reflection layer is formed on a lowermost or uppermost layer of the multi-layer structure.

Claim 35

Dependent Claim 33 words

A magneto-optical recording medium comprising: a recording film (513) having a multi-layer structure of alternate lamination of a number of metal layers (502, 503; 508, 509; 511) and dielectric layers (504; 510; 512).

Claim 36

Dependent Claim 33 words

A magneto-optical recording medium comprising: a recording film (513) having a multi-layer structure of alternate lamination of a number of metal layers (502, 503; 508, 509; 511) and dielectric layers (504; 510; 512).

Claim 37

Dependent Claim 41 words

A magneto-optical recording medium according to Claim 31 wherein said metal layer consists of at least one material layer (502; 508) selected from Pt, Pd, Rh and Au and at least one material layer (503; 509) selected from Co and Fe.

Claim 38

Dependent Claim 40 words

A magneto-optical recording medium according to Claim 31 wherein said metal layer is an alloy layer (511) of at least one element selected from Pt, Pd, Rh, Ca and Au and at least one element selected from Co and Fe.

Claim 39

Dependent Claim 30 words

A magneto-optical recording medium according to any one of Claims 31 to 33 wherein a light reflection layer is formed on a lowermost or uppermost layer of the multi-layer structure.

Claim 40

Dependent Claim 47 words

A magneto-optical recording medium according to any one of Claims 31 to 33 wherein the layers are laminated such that a total film thickness of the metal layers is not larger than 50 nm, and a light reflection layer is formed on a lowermost or uppermost layer.

Claim 41

Dependent Claim 51 words

A magneto-optical recording medium according to any one of Claims 31 to 35 wherein the dielectric layer is made of oxide, nitride, fluoride or calcogenite of a metal, and more preferably the compound is selected from the least one of SiNx, SiOx, AlNx, ZnS, AlF₃, TiO₂, BN, Al₂O₃, CrOx and Ta₂O₅.

Claim 42

Dependent Claim 59 words

A magneto-optical recording medium according to any one of Claims 31 to 36 wherein the film thickness of the metal layer or one or both of the film thickness and a refractive coefficient of the dielectric layer is controlled to maximize an output of a reproduced signal at the wavelength of the light used for recording, reproducing or erasing.

Claim 43

Dependent Claim 33 words

A magneto-optical recording medium according to Claim 34 or 35 wherein the uppermost or lowermost metal reflection film has a light reflection function, and a temperature distribution of the recording film is controlled.

Claim 44

Dependent Claim 68 words

A magneto-optical recording medium according to Claim 38 wherein the film for controlling the temperature distribution of the recording film is made of a material primarily consisting of an element selected from Al, Au, Ag, Cu, Pt, Pd and Rh with addition of at least one element selected from Ti, Ta, Cr, Nb, Ni and the metal elements other than mother metal listed in the above element group.

Claim 45

Dependent Claim 60 words

A magneto-optical recording medium having a multi-layer recording film of Claims 31 to 39 formed on a disk substrate having a guide groove, the metal reflection film formed, the multi-layer recording film formed again, and the substrate formed thereon, wherein lights are simultaneously directed from both sides or light is directed from one side to record, reproduce or erase information.

Magneto-optical recording and reproducing method, magnetooptical memory apparatus

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag