Patents by Inventor Kouji Kitsunai
Kouji Kitsunai 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).
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Patent number: 9105293Abstract: A glass substrate for a magnetic disk, wherein, in regions with respect to two places arbitrarily selected on a surface of the glass substrate on its central portion side relative to its outer peripheral end, a surface shape with a shape wavelength in a band of 60 to 500 ?m is extracted from surface shapes in each of the regions and, assuming that a root mean square roughness Rq of the surface shape is given as a microwaviness Rq, the difference between the microwavinesses Rq of the regions is 0.02 nm or less or the difference between standard deviations of the microwavinesses Rq of the regions is 0.04 nm or less.Type: GrantFiled: December 3, 2013Date of Patent: August 11, 2015Assignee: HOYA CORPORATIONInventors: Kouji Kitsunai, Takashi Maeda
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Patent number: 9012047Abstract: The shape and number of surface defects are controlled so that the occurrence of failure is suppressed in an HDD device in which a magnetic head with a very small flying height, such as a DFH head, is mounted. A magnetic disk substrate is characterized in that when laser light with a wavelength of 405 nm and a laser power of 25 mW is irradiated with a spot size of 5 ?m and scattered light from the substrate is detected, the number of defects detected to have a size of 0.1 ?m to not more than 0.3 ?m is less than 50 per 24 cm2 and, with respect to the defects, there is no defect in which, in a bearing curve obtained by a bearing curve plot method using an atomic force microscope, a portion from an apex of the defect to 45% thereof is located in an area of defect height higher than a virtual line connecting from the apex of the defect to 45% thereof.Type: GrantFiled: April 7, 2014Date of Patent: April 21, 2015Assignee: Hoya CorporationInventors: Kouji Kitsunai, Hiroshi Takeda, Yukari Senda
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Publication number: 20140220386Abstract: The shape and number of surface defects are controlled so that the occurrence of failure is suppressed in an HDD device in which a magnetic head with a very small flying height, such as a DFH head, is mounted. A magnetic disk substrate is characterized in that when laser light with a wavelength of 405 nm and a laser power of 25 mW is irradiated with a spot size of 5 ?m and scattered light from the substrate is detected, the number of defects detected to have a size of 0.1 ?m to not more than 0.3 ?m is less than 50 per 24 cm2 and, with respect to the defects, there is no defect in which, in a bearing curve obtained by a bearing curve plot method using an atomic force microscope, a portion from an apex of the defect to 45% thereof is located in an area of defect height higher than a virtual line connecting from the apex of the defect to 45% thereof.Type: ApplicationFiled: April 7, 2014Publication date: August 7, 2014Applicant: HOYA CORPORATIONInventors: Kouji KITSUNAI, Hiroshi Takeda, Yukari Senda
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Patent number: 8734967Abstract: The shape and number of surface defects are controlled so that the occurrence of failure is suppressed in an HDD device in which a magnetic head with a very small flying height, such as a DFH head, is mounted. A magnetic disk substrate is characterized in that when laser light with a wavelength of 405 nm and a laser power of 25 mW is irradiated with a spot size of 5 ?m and scattered light from the substrate is detected, the number of defects detected to have a size of 0.1 ?m to not more than 0.3 ?m is less than 50 per 24 cm2 and, with respect to the defects, there is no defect in which, in a bearing curve obtained by a bearing curve plot method using an atomic force microscope, a portion from an apex of the defect to 45% thereof is located in an area of defect height higher than a virtual line connecting from the apex of the defect to 45% thereof.Type: GrantFiled: June 29, 2009Date of Patent: May 27, 2014Assignee: Hoya CorporationInventors: Kouji Kitsunai, Hiroshi Takeda, Yukari Senda
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Publication number: 20140085750Abstract: A glass substrate for a magnetic disk, wherein, in regions with respect to two places arbitrarily selected on a surface of the glass substrate on its central portion side relative to its outer peripheral end, a surface shape with a shape wavelength in a band of 60 to 500 ?m is extracted from surface shapes in each of the regions and, assuming that a root mean square roughness Rq of the surface shape is given as a microwaviness Rq, the difference between the microwavinesses Rq of the regions is 0.02 nm or less or the difference between standard deviations of the microwavinesses Rq of the regions is 0.04 nm or less.Type: ApplicationFiled: December 3, 2013Publication date: March 27, 2014Applicant: HOYA CORPORATIONInventors: Kouji KITSUNAI, Takashi MAEDA
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Patent number: 8623530Abstract: A glass substrate for a magnetic disk, wherein, in regions with respect to two places arbitrarily selected on a surface of the glass substrate on its central portion side relative to its outer peripheral end, a surface shape with a shape wavelength in a band of 60 to 500 ?m is extracted from surface shapes in each of the regions and, assuming that a root mean square roughness Rq of the surface shape is given as a microwaviness Rq, the difference between the microwavinesses Rq of the regions is 0.02 nm or less or the difference between standard deviations of the microwavinesses Rq of the regions is 0.04 nm or less.Type: GrantFiled: July 6, 2012Date of Patent: January 7, 2014Assignee: Hoya CorporationInventors: Kouji Kitsunai, Takashi Maeda
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Publication number: 20120282493Abstract: A glass substrate for a magnetic disk, wherein, in regions with respect to two places arbitrarily selected on a surface of the glass substrate on its central portion side relative to its outer peripheral end, a surface shape with a shape wavelength in a band of 60 to 500 ?m is extracted from surface shapes in each of the regions and, assuming that a root mean square roughness Rq of the surface shape is given as a microwaviness Rq, the difference between the microwavinesses Rq of the regions is 0.02 nm or less or the difference between standard deviations of the microwavinesses Rq of the regions is 0.04 nm or less.Type: ApplicationFiled: July 6, 2012Publication date: November 8, 2012Applicant: HOYA CORPORATIONInventors: Kouji KITSUNAI, Takashi MAEDA
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Patent number: 8241769Abstract: A glass substrate for a magnetic disk, wherein, in regions with respect to two places arbitrarily selected on a surface of the glass substrate on its central portion side relative to its outer peripheral end, a surface shape with a shape wavelength in a band of 60 to 500 ?m is extracted from surface shapes in each of the regions and, assuming that a root mean square roughness Rq of the surface shape is given as a microwaviness Rq, the difference between the microwavinesses Rq of the regions is 0.02 nm or less or the difference between standard deviations of the microwavinesses Rq of the regions is 0.04 nm or less.Type: GrantFiled: December 24, 2008Date of Patent: August 14, 2012Assignee: Hoya CorporationInventors: Kouji Kitsunai, Takashi Maeda
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Publication number: 20110109994Abstract: The shape and number of surface defects are controlled so that the occurrence of failure is suppressed in an HDD device in which a magnetic head with a very small flying height, such as a DFH head, is mounted. A magnetic disk substrate is characterized in that when laser light with a wavelength of 405 nm and a laser power of 25 mW is irradiated with a spot size of 5 ?m and scattered light from the substrate is detected, the number of defects detected to have a size of 0.1 ?m to not more than 0.3 ?m is less than 50 per 24 cm2 and, with respect to the defects, there is no defect in which, in a bearing curve obtained by a bearing curve plot method using an atomic force microscope, a portion from an apex of the defect to 45% thereof is located in an area of defect height higher than a virtual line connecting from the apex of the defect to 45% thereof.Type: ApplicationFiled: June 29, 2009Publication date: May 12, 2011Applicant: HOYA CORPORATIONInventors: Kouji Kitsunai, Hiroshi Takeda, Yukari Senda
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Publication number: 20100273030Abstract: A glass substrate for a magnetic disk, wherein, in regions with respect to two places arbitrarily selected on a surface of the glass substrate on its central portion side relative to its outer peripheral end, a surface shape with a shape wavelength in a band of 60 to 500 ?m is extracted from surface shapes in each of the regions and, assuming that a root mean square roughness Rq of the surface shape is given as a microwaviness Rq, the difference between the microwavinesses Rq of the regions is 0.02 nm or less or the difference between standard deviations of the microwavinesses Rq of the regions is 0.04 nm or less.Type: ApplicationFiled: December 24, 2008Publication date: October 28, 2010Applicant: HOYA CORPORATIONInventors: Kouji KITSUNAI, Takashi MAEDA