Patents by Inventor Shigeki Takagawa
Shigeki Takagawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Patent number: 8846173Abstract: There is provided an optical recording medium including a substrate, an information recording layer that is formed on the substrate and has a single film structure formed by an oxide including W and Ru, and a light transmissive layer that is formed on the information recording layer.Type: GrantFiled: June 10, 2013Date of Patent: September 30, 2014Assignee: Sony CorporationInventors: Yo Ota, Shigeki Takagawa, Hiroshi Uchiyama
-
Publication number: 20140011039Abstract: There is provided an optical recording medium including a substrate, an information recording layer that is formed on the substrate and has a single film structure formed by an oxide including W and Ru, and a light transmissive layer that is formed on the information recording layer.Type: ApplicationFiled: June 10, 2013Publication date: January 9, 2014Inventors: Yo Ota, Shigeki Takagawa, Hiroshi Uchiyama
-
Patent number: 8470429Abstract: An optical recording medium includes a support substrate, and a semi-transmissive recording layer including a first dielectric layer, a semi-transmissive semi-reflective layer, a second dielectric layer, a phase-change recording material layer, and a third dielectric layer which are laminated in that order from the support substrate side. The semi-transmissive semi-reflective layer is composed of silver, and the first dielectric layer includes a composite oxide layer using niobium oxide.Type: GrantFiled: July 18, 2011Date of Patent: June 25, 2013Assignee: Sony CorporationInventors: Kotaro Kurokawa, Shigeki Takagawa
-
Patent number: 8465822Abstract: An optical recording medium includes a support substrate and a semi-transmissive recording layer. The semi-transmissive recording layer includes a first dielectric layer, a semi-transmissive semi-reflective layer, a second dielectric layer, a phase change recording material layer, and a third dielectric layer that are sequentially stacked in that order on the support substrate. The semi-transmissive semi-reflective layer contains silver. The second dielectric layer has a stack structure including a lower layer disposed at the interface on the semi-transmissive semi-reflective layer side and an upper layer disposed on the phase change recording material layer side of the lower layer. The lower layer is composed of indium oxide or a composite oxide of indium oxide and tin oxide. The upper layer is composed of tantalum oxide, gallium oxide, zirconium oxide, or niobium oxide.Type: GrantFiled: July 15, 2011Date of Patent: June 18, 2013Assignee: Sony CorporationInventors: Kotaro Kurokawa, Shigeki Takagawa
-
Patent number: 8409686Abstract: An optical recording medium having three or more information recording layers reduces crosstalk caused by multi-reflected beams and improves signal quality. In the optical recording medium having three or more information recording layers, the refractive index of a plurality of intermediate layers disposed between adjacent information recording layers is greater than the refractive index of a cover layer disposed between a light incident surface and an information recording layer being the closest from the light incident surface.Type: GrantFiled: September 15, 2010Date of Patent: April 2, 2013Assignees: TDK Corporation, Panasonic Corporation, Sony CorporationInventors: Hiroyasu Inoue, Takashi Kikukawa, Koji Mishima, Yoshiaki Komma, Joji Anzai, Jun Nakano, Manami Miyawaki, Shigeki Takagawa
-
Patent number: 8241834Abstract: An optical recording medium includes a substrate having features that define track regions, an optical recording layer disposed on the substrate, and a light-transmitting layer disposed on the optical recording layer. The optical recording layer has a composition of (Sb2Se3)wTexOyPdz, where w, x, y, and z each represent a molar percent and satisfy 10 (mol %)?w?60 (mol %), 0 (mol %)<x?60 (mol %), 30 (mol %)?y?60 (mol %), 10 (mol %)?z?30 (mol %), and w+x+y+z=100.Type: GrantFiled: April 14, 2009Date of Patent: August 14, 2012Assignee: Sony CorporationInventors: Kouichi Yasuda, Shigeki Takagawa
-
Patent number: 8206805Abstract: An object of the invention is to provide an optical recording medium and a method for producing an optical recording medium that enable to improve the quality of a servo signal and a reproduction signal. The optical recording medium satisfies: t3?t4?1 ?m, t4?t2?1 ?m, t2?10 ?m, and t1?(t2+t3+t4)?1 ?m, where t1 is a thickness between a surface of the optical recording medium, and the first information recording surface, t2 is a thickness between the first optical recording surface and the second information recording surface, t3 is a thickness between the second optical recording surface and the third information recording surface, and t4 is a thickness between the third optical recording surface and the fourth information recording surface.Type: GrantFiled: October 16, 2009Date of Patent: June 26, 2012Assignees: Panasonic Corporation, TDK Corporation, Sony CorporationInventors: Yoshiaki Komma, Joji Anzai, Hiroyasu Inoue, Takashi Kikukawa, Koji Mishima, Jun Nakano, Manami Miyawaki, Shigeki Takagawa
-
Publication number: 20120027979Abstract: An optical recording medium includes a support substrate, and a semi-transmissive recording layer including a first dielectric layer, a semi-transmissive semi-reflective layer, a second dielectric layer, a phase-change recording material layer, and a third dielectric layer which are laminated in that order from the support substrate side. The semi-transmissive semi-reflective layer is composed of silver, and the first dielectric layer includes a composite oxide layer using niobium oxide.Type: ApplicationFiled: July 18, 2011Publication date: February 2, 2012Applicant: SONY CORPORATIONInventors: Kotaro Kurokawa, Shigeki Takagawa
-
Publication number: 20120027980Abstract: An optical recording medium includes a support substrate and a semi-transmissive recording layer. The semi-transmissive recording layer includes a first dielectric layer, a semi-transmissive semi-reflective layer, a second dielectric layer, a phase change recording material layer, and a third dielectric layer that are sequentially stacked in that order on the support substrate. The semi-transmissive semi-reflective layer contains silver. The second dielectric layer has a stack structure including a lower layer disposed at the interface on the semi-transmissive semi-reflective layer side and an upper layer disposed on the phase change recording material layer side of the lower layer. The lower layer is composed of indium oxide or a composite oxide of indium oxide and tin oxide. The upper layer is composed of tantalum oxide, gallium oxide, zirconium oxide, or niobium oxide.Type: ApplicationFiled: July 15, 2011Publication date: February 2, 2012Applicant: SONY CORPORATIONInventors: Kotaro Kurokawa, Shigeki Takagawa
-
Patent number: 7972673Abstract: An optical recording medium is provided. The optical recording medium includes at least a reflective film and a cover layer on a substrate; main data by a combination of pit and land are recorded on the substrate; a write-once recording is made to be possible on the reflective film by irradiating a laser light; sub-data are recorded by a mark that is formed by the irradiation of laser light for the write-once recording with respect to the reflective film; a reproducing signal level at portion where said mark is formed increases for the land of specified length; the mark by which the reproduced level decreases at the portion where the mark is formed is formed for an optical disc recording medium manufactured by physical copy; the reflective film is composed of an Ag-alloy film of Ag100-xXx(0<x<100); and the X is selected from Ti, W, Ta, V, Mo, Nb and Zr.Type: GrantFiled: October 25, 2006Date of Patent: July 5, 2011Assignee: Sony CorporationInventors: Tetsuhiro Sakamoto, Takashi Shimouma, Shigeki Takagawa, Jun Nakano, Goro Fujita
-
Patent number: 7924672Abstract: In an optical disk, a substrate has main data recorded in the form of a combination of pits and lands on one side thereof, and at least a reflective layer and cover layer are stacked on the substrate to cover the pits and lands on the substrate. To the optical disk, sub data is recorded in the form of marks formed by irradiating writing-power laser light to the reflective layer. The marks are formed so that reading signal level will be raised where the marks are formed while it will be lowered where the marks are formed in a counterfeit disk produced based on an authenticated disk, namely, the reading signal level where the marks are formed is different in polarity between in the authenticated and counterfeit disks. Further, in a player for the optical disk, discrimination is made between the authenticated and counterfeit disks by detecting the sub data recorded in the optical disk and judging whether the value of the detected sub data has been read at a correct polarity.Type: GrantFiled: February 7, 2006Date of Patent: April 12, 2011Assignee: Sony CorporationInventors: Goro Fujita, Takashi Shimouma, Jun Nakano, Shigeki Takagawa, Kimihiro Saito
-
Publication number: 20110076436Abstract: An optical recording medium having three or more information recording layers reduces crosstalk caused by multi-reflected beams and improves signal quality. In the optical recording medium having three or more information recording layers, the refractive index of a plurality of intermediate layers disposed between adjacent information recording layers is greater than the refractive index of a cover layer disposed between a light incident surface and an information recording layer being the closest from the light incident surface.Type: ApplicationFiled: September 15, 2010Publication date: March 31, 2011Inventors: Hiroyasu INOUE, Takashi KIKUKAWA, Koji MISHIMA, Yoshiaki KOMMA, Joji ANZAI, Jun NAKANO, Manami MIYAWAKI, Shigeki TAKAGAWA
-
Publication number: 20100143637Abstract: An object of the invention is to provide an optical recording medium and a method for producing an optical recording medium that enable to improve the quality of a servo signal and a reproduction signal. The optical recording medium satisfies: t3?t4?1 ?m, t4?t2?1 ?m, t2?10 ?m, and t1?(t2+t3+t4)?1 ?m, where t1 is a thickness between a surface of the optical recording medium, and the first information recording surface, t2 is a thickness between the first optical recording surface and the second information recording surface, t3 is a thickness between the second optical recording surface and the third information recording surface, and t4 is a thickness between the third optical recording surface and the fourth information recording surface.Type: ApplicationFiled: October 16, 2009Publication date: June 10, 2010Inventors: Yoshiaki KOMMA, Joji Anzai, Hiroyasu Inoue, Takashi Kikukawa, Koji Mishima, Jun Nakano, Manami Miyawaki, Shigeki Takagawa
-
Publication number: 20090274033Abstract: An optical recording medium includes a substrate having features that define track regions, an optical recording layer disposed on the substrate, and a light-transmitting layer disposed on the optical recording layer. The optical recording layer has a composition of (Sb2Se3)wTexOyPdz, where w, x, y, and z each represent a molar percent and satisfy 10 (mol %)?w?60 (mol %), 0 (mol %)<x?60 (mol %), 30 (mol %)?y?60 (mol %), 10 (mol %)?z?30 (mol %), and w+x+y+z=100.Type: ApplicationFiled: April 14, 2009Publication date: November 5, 2009Applicant: SONY CORPORATIONInventors: Kouichi Yasuda, Shigeki Takagawa
-
Publication number: 20090262640Abstract: An optical-disc manufacturing method including the steps of: fabricating a pre-exposure disc master by forming, on a substrate, a heat accumulation layer having a thickness of 17% or less of a recording-laser wavelength and forming an inorganic resist layer; performing exposure of a recording-signal pattern having pits and spaces with respect to the inorganic resist layer of the disc master, by performing recording-laser light irradiation; fabricating a disc master having a pit-array shape having pits and spaces, by performing development processing after the exposure; manufacturing a stamper to which the pit-array shape is transferred, by using the disc master having the pit-array shape; and manufacturing an optical disc having a predetermined layer structure including a recording layer to which the pit-array shape of the stamper is transferred and in which a silver or silver-alloy reflective film is formed on the pit-array shape.Type: ApplicationFiled: March 3, 2009Publication date: October 22, 2009Applicant: Sony CorporationInventors: Kensaku TAKAHASHI, Jun NAKANO, Shin MASUHARA, Tetsuhiro SAKAMOTO, Shigeki TAKAGAWA
-
Publication number: 20090010115Abstract: In an optical disk, a substrate has main data recorded in the form of a combination of pits and lands on one side thereof, and at least a reflective layer and cover layer are stacked on the substrate to cover the pits and lands on the substrate. To the optical disk, sub data is recorded in the form of marks formed by irradiating writing-power laser light to the reflective layer. The marks are formed so that reading signal level will be raised where the marks are formed while it will be lowered where the marks are formed in a counterfeit disk produced based on an authenticated disk, namely, the reading signal level where the marks are formed is different in polarity between in the authenticated and counterfeit disks. Further, in a player for the optical disk, discrimination is made between the authenticated and counterfeit disks by detecting the sub data recorded in the optical disk and judging whether the value of the detected sub data has been read at a correct polarity.Type: ApplicationFiled: February 7, 2006Publication date: January 8, 2009Applicant: SONY CORPORATIONInventors: Goro Fujita, Takashi Shimouma, Jun Nakano, Shigeki Takagawa, Kimihiro Saito
-
Publication number: 20070097849Abstract: An optical recording medium is provided. The optical recording medium includes at least a reflective film and a cover layer on a substrate; main data by a combination of pit and land are recorded on the substrate; a write-once recording is made to be possible on the reflective film by irradiating a laser light; sub-data are recorded by a mark that is formed by the irradiation of laser light for the write-once recording with respect to the reflective film; a reproducing signal level at portion where said mark is formed increases for the land of specified length; the mark by which the reproduced level decreases at the portion where the mark is formed is formed for an optical disc recording medium manufactured by physical copy; the reflective film is composed of an Ag-alloy film of Ag100?xXx(0<x<100); and the X is selected from Ti, W, Ta, V, Mo, Nb and Zr.Type: ApplicationFiled: October 25, 2006Publication date: May 3, 2007Applicant: SONY CORPORATIONInventors: Tetsuhiro Sakamoto, Takashi Shimouma, Shigeki Takagawa, Jun Nakano, Goro Fujita
-
Patent number: 6999396Abstract: An initialization method of an optical recording medium having a plurality of optical recording layers capable of reducing initialization unevenness due to light interference caused at the time of initialization without deteriorating information recording/reproducing signal characteristics of the optical recording layers is provided.Type: GrantFiled: February 7, 2003Date of Patent: February 14, 2006Assignee: Sony CorporationInventors: Kotaro Kurokawa, Takeshi Yamasaki, Daisuke Ueda, Shigeki Takagawa, Masanobu Yamamoto
-
Publication number: 20040145999Abstract: An initialization method of an optical recording medium having a plurality of optical recording layers capable of reducing initialization unevenness due to light interference caused at the time of initialization without deteriorating information recording/reproducing signal characteristics of the optical recording layers is provided.Type: ApplicationFiled: March 15, 2004Publication date: July 29, 2004Inventors: Kotaro Kurokawa, Takeshi Yamasaki, Daisuke Ueda, Shigeki Takagawa, Masanobu Yamamoto
-
Patent number: 5768221Abstract: A multiple-recording-layer optical recording medium has a plurality of recording layers to be initialized by exposure to light, with a transparent layer interposed between the recording layers. Light is applied simultaneously to the to the recording layers to initialize the recording layers simultaneously.Type: GrantFiled: September 19, 1996Date of Patent: June 16, 1998Assignee: Sony CorporationInventors: Yutaka Kasami, Koichi Yasuda, Atsushi Fukumoto, Shigeki Takagawa