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Optical memory medium and its information recording and erasing method and apparatus
| Details |
Inventors: Sato, Yoshio; Watanabe, Atsumi; Shimada, Satoshi; Sasaki, Hiroshi; Tsuboi, Nobuyoshi; Nihei, Hideki; Miyamoto, Norifumi; Koyanagi, Hiroaki; Minemura, Hiroyuki;
Assignee: Hitachi, Ltd. (Tokyo, JP)
Primary Examiner: Nguyen; Hoa
Assistant Examiner:
Attorney, Agent or Firm: Antonelli, Terry, Stout & Kraus
An information recording and erasing method and apparatus of an optical memory medium including a substrate, a guard film, and an intermediate layer portion so disposed between said substrate and said guard film as to include at least a recording material layer having a phase changing with temperature and include at least one good conductor layer, comprising the steps of supplying magnetic flux varying relatively to said good conductor layer to generate eddy currents within said good conductor layer, and heating said recording material layer with heat generated in said good conductor due to the eddy current loss to effect information recording and erasing with respect to said recording material layer. |
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DETAILED DESCRIPTION An object of the present invention is to provide such an optical memory medium that it is heated from the inside to prevent the substrate from being heated and the contents of the memory can be rewritten at high speed.
Another object of the present invention is to provide an information erasing method and its apparatus capable of rewriting data onto a memory at high speed without hampering the thermal stability.
In according with the conventional information recording and erasing method of a rewritable optical disk, the laser light is applied to the disk to supply the memory medium with thermal energy.
This method is based upon the principle that the energy of the light enters the memory medium and vibrates molecules within the medium to heat it.
The present inventors perceived that a change in the magnetic flux supplied to a conductor causes an eddy current and heat is generated by this eddy current loss.
By utilizing this fact, it is attempted to record and erase the information.
That is to say, at least one layer of an optical memory medium is made as a good conductor layer, and a change in the magnetic flux is supplied from the outside to the good conductor layer to generate heat.
A recording material layer is thus heated to record and erase the information.
That is to say, a change in the magnetic flux is supplied to the medium for attaining the erasing operation.
As compared with the conventional erasing operation using laser light, a wider region of the optical memory medium can be heated.
As a result, a wider region can be erased at a time and erasing can be effected at high speed.
In the recording operation, a change in magnetic flux is supplied to preheat the recording material and thereafter laser light is applied thereto to produce a phase change in the recording material, the data being recorded.
As compared with the case where only the laser light is supplied to the recording material, therefore, the recording speed can be increased.
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Active Solid-state 
