Apparatus and method for recording, reproducing and erasing on optical recording discs
First Claim
Patent Images
1. A method of erasing information optically recorded in a thin recording film in the form of a distribution of thermally denatured regions therein comprising the steps of:
- producing at least two light beams,focusing said at least two light beams to form at least two focused light beams on said thin recording film,sweeping said at least two focused light beams successively along one track of recording on said thin recording film, andapplying said at least two focused light beams on said thin recording film so as to successively result in a higher heated part and later a less heated part along said one track.
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Abstract
An apparatus for recording, reproducing and erasing for an optical recording disc capable of recording information data with a high density, and capable of recording new information data and simultaneously erasing the previously recorded information data.
39 Citations
12 Claims
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1. A method of erasing information optically recorded in a thin recording film in the form of a distribution of thermally denatured regions therein comprising the steps of:
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producing at least two light beams, focusing said at least two light beams to form at least two focused light beams on said thin recording film, sweeping said at least two focused light beams successively along one track of recording on said thin recording film, and applying said at least two focused light beams on said thin recording film so as to successively result in a higher heated part and later a less heated part along said one track. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for recording, reproducing and erasing for an optical recording disc, at least the surface of which changes its structure from a first state to a second state which is optically different from said first state by heating followed by quick cooling, and restores to said first state by heating followed by slow cooling, the apparatus comprising:
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at least two light sources for producing light beams including a first light beam and irradiating selected localized parts on a single recording track on said recording disc, at least one light detecting means for detecting a light beam from said recording disc by reflection or transmission due to said first light beam, an optical means for focusing and sweeping said light beams along said recording track, based upon output signals of the light detecting means, a controlling means for selectively switching the operation of the apparatus among the following operations; (i) for recording information data on said recording disc, a selected light beam from said light sources and modulated by information is irradiated on said recording disc, (ii) for reproducing information data from said recording disc, said first light beam having a lower intensity level and a shorter wavelength than that for said recording is irradiated onto said recording disc, and (iii) for erasing information data from said recording disc, at least two of said light beams, one of them having a higher intensity level than that for said reproducing, are successively irradiated onto said recording disc. - View Dependent Claims (10, 11, 12)
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7. An apparatus for recording, reproducing and erasing for an optical recording disc, at least the surface of which changes its structure from a first state to a second state which is optically different from said first state by heating followed by quick cooling for recording, and restores to said first state by heating followed by slow cooling for erasing, the apparatus comprising:
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at least two light sources for producing light beams including a first light beam and irradiating selected localized parts on a single recording track on said recording disc, at least one light detecting means for detecting a light beam from said recording disc by reflection or transmission due to said first light beam, an optical means for focusing and sweeping said light beams along said recording track, based upon output signals of the light detecting means, a controlling means for selectively switching the operation of the apparatus among the following operations; (i) for recording information data on said recording disc, a selected light beam from said light sources and modulated by information is irradiated on said recording disc, (ii) for reproducing information data from said recording disc, said first light beam having a lower intensity level than that for said recording is irradiated onto said recording disc, and (iii) for erasing information data from said recording disc, at least two of said light beams, one of them having a higher intensity level than that for said reproducing, are successively irradiated along said single recording track on said recording disc. - View Dependent Claims (8, 9)
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Specification