Patent EP0415449A2 successfully refreshed from Google Patents.
EP0415449A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Playback method for magnetooptical recording
Assignee: Sony Corp
•
Filing: 1990-08-31
•
Granted: —
•
Expires: 2010-08-31
Abstract
Abstract A high density magnetooptical recording and playback method is disclosed. The magnetooptical recording medium (3) comprises a recording hold magnetic layer (2) and a playback magnetic layer (1) magnetically coupled with each other. Prior to the playback operation, the playback magnetic layer is initialized by an external magnetic field. A laser light is irradiated to locally heat the medium and cause transfer of magnetization in the recording hold magnetic layer to the playback magnetic layer. The signal is read out by the interaction of the laser light and the transferred magnetization.
Inventors
- 👤 Katsuhisa Aratani
- 👤 Atsushi Fukumoto
- 👤 Masumi Ohta
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 04:31
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10517; G11B11/10515; G11B11/10582; G11B11/10586
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
128 words
A method for playback signal from a magnetooptical recording medium comprising the steps of, a) preparing a magnetic recording medium having a recording hold magnetic layer and a playback magnetic layer magnetically coupled with each other, said recording hold magnetic layer having recording information in said layer as the direction of magnetization, b) applying an initializing external magnetic field to arrange magnetization of said playback magnetic layer in one direction without affecting to the magnetization in said recording hold magnetic layer. c) irradiating' a laser light to said magnetooptical recording medium to locally heat the medium to cause transfer of the magnetization in said recording hold magnetic layer to said playback magnetic layer, to read out information by the interaction of said laser light and said transferred magnetization.
Claim 2
Independent Claim
128 words
A method for playback signal from a magnetooptical recording medium comprising the steps of, a) preparing a magnetic recording medium having a recording hold magnetic layer and a playback magnetic layer magnetically coupled with each other, said recording hold magnetic layer having recording information in said layer as the direction of magnetization, b) applying an initializing external magnetic field to arrange magnetization of said playback magnetic layer in one direction without affecting to the magnetization in said recording hold magnetic layer. c) irradiating' a laser light to said magnetooptical recording medium to locally heat the medium to cause transfer of the magnetization in said recording hold magnetic layer to said playback magnetic layer, to read out information by the interaction of said laser light and said transferred magnetization.
Claim 3
Dependent Claim
20 words
A method according to claim 1, said recording hold magnetic layer and said playback magnetic layer is magneto stablically coupled.
Claim 4
Dependent Claim
24 words
A method according to claim 1, said recording hold magnetic layer and said playback magnetic layer is exchange coupled through an intermediate magnetic layer.
Claim 5
Dependent Claim
31 words
A method according to claim 1, said magnetooptical recording medium is recorded by applying magnetic field modulated according to information signal to be recorded while being irradiated by a laser light.
Claim 6
Dependent Claim
64 words
A method according to claim 1, said magnetooptical recording medium further comprises a perpendicular magnetization magnetic recording layer adjacently provided to said recording hold magnetic layer to which signal is recorded by use of a magnetic head and recorded signal on said perpendicular magnetization magnetic recording layer is magnetically transferred to said recording hold magnetic layer by irradiating a laser light to said medium.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.