# US 7,613,091 B2 · Method for identifying double-layer disc and optical disc apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,613,091 B2 - Document ID: US7613091B2 - Status: Granted - Kind: B2 - Application number: 11/336,911 - Filed: 2006-01-23 - Published: 2006-07-27 - Granted: 2009-11-03 - Earliest claimed: 2003-07-23 - Assignees: Ricoh Company, Ltd. - Inventors: Michiaki Shinotsuka; Hiroyuki Iwasa; Masaru Shinkai - Web page: https://patentgrep.com/patent/US7613091B2 ## CPC - G11B 19/127: {involving detection of the number of sides, e.g. single or double, or layers, e.g. for multiple recording or reproducing layers} - G11B 7/004: Recording, reproducing or erasing methods; Read, write or erase circuits therefor {(magneto-optical systems G11B11/105)} - G11B 7/24: Record carriers characterised by shape, structure or physical properties, or by the selection of the material (characterised by the arrangement of information on the carrier G11B7/007) - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract The object of the present invention is to enable the identification of double-layer disc type (recordable double-layer disc, rewritable double-layer disc and ROM-type double-layer disc) to be easily and accurately performed. The method for identifying double-layer disc contains obtaining a reflectance of each light by irradiating light of different wavelengths under focused state to each layer of a double-layer disc loaded in an optical apparatus, and identifying if the double-layer disc is a recordable double-layer disc, a rewritable double-layer disc or a ROM-type double-layer disc corresponding to the combination of reflectance of each obtained light. It is preferable that the wavelength of one light is a wavelength for DVD-based disc and the wavelength of the other light is a wavelength for CD-based disc. ## Claims ### Claim 1 A method for identifying a double-layer disc comprising: obtaining a reflectance of each light by irradiating light of different wavelengths under focused state to each layer of a double-layer disc loaded in an optical apparatus, and identifying if the double-layer disc is a recordable double-layer disc, a rewritable double-layer disc or a ROM-type double-layer disc corresponding to the combination of reflectance of each obtained light, wherein when the combination of reflectance of each obtained light is 15% or more for both lights, it is identified as a ROM-type double-layer disc, when the reflectance of one light is 15% or more and the reflectance of the other light is 4% or more and less than 15%, it is identified as a recordable double-layer disc, and when the reflectance of both lights is 4% or more and less than 15%, it is identified as a rewritable double-layer disc. ### Claim 2 (depends on 1) The method for identifying double-layer disc according to claim 1, wherein when the combination of reflectance of each obtained light is less than 4% for both lights, it is identified as a nonstandard disc. ### Claim 3 (depends on 2) The method for identifying double-layer disc according to claim 2, wherein when the reflectance of the light of DVD wavelength is 15% or more and the reflectance of the light of CD wavelength is 4% or more and less than 15%, it is identified as a recordable double-layer disc. ### Claim 4 An optical disc apparatus comprising: an optical pickup which contains two light sources of different wavelengths and selectively irradiates each light to a loaded disc, a number identification unit for recording layer which identifies if the loaded disc is a double-layer disc in a disc type identification mode, a reflectance calculating unit in which a reflectance of each light is obtained by irradiating light of different wavelengths under focused state to each layer of a double-layer disc using the optical pickup when the loaded disc is a double-layer disc, and a double-layer disc identification unit which identifies if the double-layer disc is a recordable double-layer disc, a rewritable double-layer disc or a ROM-type double-layer disc corresponding to the combination of reflectance of each obtained light. ### Claim 5 (depends on 4) The optical disc apparatus according to claim 4, wherein the wavelength of the light irradiated from one light source is a wavelength for DVD-based disc and the wavelength of the light irradiated from the other light source is a wavelength for CD-based disc. ### Claim 6 (depends on 4) The optical disc apparatus according to claim 4, wherein the double-layer identification unit identifies it as a ROM-type double-layer disc when the combination of reflectance of each obtained light is 15% or more for both lights, as a recordable double-layer disc when the reflectance of one light is 15% or more and the reflectance of the other light is 4% or more and less than 15%, and as a rewritable double-layer disc when the reflectance of both lights is 4% or more and less than 15%. ### Claim 7 (depends on 6) The optical disc apparatus according to claim 6, wherein the double-layer disc identification unit identifies it as a nonstandard disc when the combination of reflectance of each obtained light is less than 4% for both lights. ### Claim 8 (depends on 5) The optical disc apparatus according to claim 5, wherein when the reflectance of the light of DVD wavelength is 15% or more and the reflectance of the light of CD wavelength is 4% or more and less than 15%, it is identified as a recordable double-layer disc.