Optical recording medium, method of manufacturing optical recording medium, recording method and reproducing method
AssigneeSony Corporation
InventorsGoro Fujita, Kimihiro Saito
Life of this patent
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Abstract
An optical recording medium includes recording layers and intermediate layers. The recording layers include a diffraction grating that has a predetermined grating pitch and is obtained by alternately laminating first layers and second layers being transparent and having slightly different refractive indexes. The intermediate layers are transparent and have a larger thickness than that of the recording layers. In the optical recording medium, the recording layers and the intermediate layers are alternately laminated.
Claims7
An optical recording medium, comprising:
- recording layers including a diffraction grating having a predetermined grating pitch, the diffraction grating being obtained by alternately laminating first layers and second layers being transparent and having slightly different refractive indexes;
- and
- intermediate layers being transparent and having a larger thickness than that of the recording layers, the recording layers and the intermediate layers being alternately laminated.
A method of manufacturing an optical recording medium in which recording layers and intermediate layers are alternately laminated, the method comprising:
- generating the recording layers including a diffraction grating, the diffraction grating being provided with a predetermined grating pitch by alternately laminating a first material and a second material that are transparent and have slightly different refractive indexes, into predetermined thicknesses at a several number of times;
- and
- generating the intermediate layers that are transparent and have a thickness larger than that of the recording layers.
A recording method of recording a deletion mark on an optical recording medium according to recording information, comprising
- emitting a laser beam according to the recording information with a focus position of the laser beam matching with a recording layer of the optical recording medium as a target for recording, and planarizing a refractive index distribution on the recording layer as the target for the recording, the optical recording medium being configured by alternately laminating the recording layers and intermediate layers, the recording layers including a diffraction grating provided with a predetermined grating pitch by alternately laminating first layers and second layers that are transparent and have refractive indexes being slightly different from each other, the intermediate layers being transparent and having a larger thickness than that of the recording layers.
A reproducing method for an optical recording medium, comprising:
- emitting a laser beam to the optical recording medium where a deletion mark corresponding to recording information is formed on recording layers of the optical recording medium with the laser beam being focused on the recording layer as a target for reproduction, the optical recording medium being configured by alternately laminating the recording layers and intermediate layers, the recording layers including a diffraction grating provided with a predetermined grating pitch by alternately laminating first layers and second layers that are transparent and have refractive indexes being slightly different from each other, the intermediate layers being transparent and having a larger thickness than that of the recording layers;
- detecting reflected light of the laser beam emitted at the emitting a laser beam;
- and
- reproducing the information recorded on the recording layer as the target for reproduction based on a detected result of the reflected light at the detecting reflected light.
Dependencies are inferred from the claim text.