Patents Assigned to Hoya Glass Disk (thailand) Ltd.
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Publication number: 20170270956Abstract: A magnetic disk substrate having a flat main surface, an end face, and a chamfered face formed between the main surface and the end face. The substrate has an offset portion, present on the main surface within a range of 92.0 to 97.0% in a radial direction from a center of the substrate. A distance from the center of the substrate to the end face of the substrate in a radial direction is 100%, the offset portion being raised or lowered with respect to a virtual straight line connecting two points on the main surface, set at positions of 92.0% and 97.0%. A maximum distance from the virtual straight line to the offset portion in a direction perpendicular to the virtual straight line is a “maximum offset value.Type: ApplicationFiled: June 1, 2017Publication date: September 21, 2017Applicants: HOYA CORPORATION, HOYA GLASS DISK (Thailand) LTD.Inventors: Toshio TAKIZAWA, Kraisorn PHANDON, Kenichi NISHIMORI
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Patent number: 9704526Abstract: With regard to a glass substrate 1 according to the present invention, a value of an amendment concentricity AC that has taken into consideration Sk and/or Ku calculated from a shape profile over the whole circumference of an inside hole, or the skewness is within a predetermined range. The glass substrate for a magnetic recording medium can stably read servo information including track information stored on a magnetic disk when the glass substrate is used for an HDD.Type: GrantFiled: June 8, 2015Date of Patent: July 11, 2017Assignees: HOYA CORPORATION, HOYA GLASS DISK (Thailand) LTD.Inventor: Kenichi Nishimori
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Patent number: 9697861Abstract: A magnetic disk substrate having a flat main surface, an end face, and a chamfered face formed between the main surface and the end face. The substrate has an offset portion, present on the main surface within a range of 92.0 to 97.0% in a radial direction from a center of the substrate. A distance from the center of the substrate to the end face of the substrate in a radial direction is 100%, the offset portion being raised or lowered with respect to a virtual straight line connecting two points on the main surface, set at positions of 92.0% and 97.0%. A maximum distance from the virtual straight line to the offset portion in a direction perpendicular to the virtual straight line is a “maximum offset value.Type: GrantFiled: August 5, 2015Date of Patent: July 4, 2017Assignees: HOYA CORPORATION, HOYA GLASS DISK (Thailand) LTD.Inventors: Toshio Takizawa, Kraisorn Phandon, Kenichi Nishimori
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Patent number: 9685185Abstract: With regard to a glass substrate 1 according to the present invention, a value of an amendment concentricity AC that has taken into consideration Sk and/or Ku calculated from a shape profile over the whole circumference of an inside hole, or the skewness is within a predetermined range. The glass substrate for a magnetic recording medium can stably read servo information including track information stored on a magnetic disk when the glass substrate is used for an HDD.Type: GrantFiled: June 8, 2015Date of Patent: June 20, 2017Assignees: HOYA CORPORATION, HOYA GLASS DISK (Thailand) LTD.Inventor: Kenichi Nishimori
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Publication number: 20150340054Abstract: A magnetic disk substrate having a flat main surface, an end face, and a chamfered face formed between the main surface and the end face. The substrate has an offset portion, present on the main surface within a range of 92.0 to 97.0% in a radial direction from a center of the substrate. A distance from the center of the substrate to the end face of the substrate in a radial direction is 100%, the offset portion being raised or lowered with respect to a virtual straight line connecting two points on the main surface, set at positions of 92.0% and 97.0%. A maximum distance from the virtual straight line to the offset portion in a direction perpendicular to the virtual straight line is a “maximum offset value.Type: ApplicationFiled: August 5, 2015Publication date: November 26, 2015Applicants: HOYA CORPORATION, HOYA GLASS DISK (Thailand) LTD.Inventors: Toshio TAKIZAWA, Kraisorn PHANDON, Kenichi NISHIMORI
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Patent number: 9183866Abstract: A magnetic disk substrate having a flat main surface, an end face, and a chamfered face formed between the main surface and the end face. The substrate has an offset portion, present on the main surface within a range of 92.0 to 97.0% in a radial direction from a center of the substrate. A distance from the center of the substrate to the end face of the substrate in a radial direction is 100%, the offset portion being raised or lowered with respect to a virtual straight line connecting two points on the main surface, set at positions of 92.0% and 97.0%. A maximum distance from the virtual straight line to the offset portion in a direction perpendicular to the virtual straight line is a “maximum offset value.Type: GrantFiled: November 24, 2014Date of Patent: November 10, 2015Assignees: HOYA CORPORATION, HOYA GLASS DISK (Thailand) LTD.Inventors: Toshio Takizawa, Kraisorn Phandon, Kenichi Nishimori
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Publication number: 20150269960Abstract: With regard to a glass substrate 1 according to the present invention, a value of an amendment concentricity AC that has taken into consideration Sk and/or Ku calculated from a shape profile over the whole circumference of an inside hole, or the skewness is within a predetermined range. The glass substrate for a magnetic recording medium can stably read servo information including track information stored on a magnetic disk when the glass substrate is used for an HDD.Type: ApplicationFiled: June 8, 2015Publication date: September 24, 2015Applicants: HOYA GLASS DISK (THAILAND) LTD., HOYA CORPORATIONInventor: Kenichi NISHIMORI
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Publication number: 20150269961Abstract: With regard to a glass substrate 1 according to the present invention, a value of an amendment concentricity AC that has taken into consideration Sk and/or Ku calculated from a shape profile over the whole circumference of an inside hole, or the skewness is within a predetermined range. The glass substrate for a magnetic recording medium can stably read servo information including track information stored on a magnetic disk when the glass substrate is used for an HDD.Type: ApplicationFiled: June 8, 2015Publication date: September 24, 2015Applicants: HOYA GLASS DISK (THAILAND) LTD., HOYA CORPORATIONInventor: Kenichi NISHIMORI
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Publication number: 20150109703Abstract: A magnetic disk substrate highly reliable to prevent the occurrence of crash failure even if a magnetic disk is rotated at high speed, and suitable for a hard disk that starts and stops by the load/unload method, and a magnetic disk using such a substrate. The representative structure of the magnetic disk substrate is a disk-shaped glass substrate 10 having a generally flat main surface 11, an end face 12, a chamfered face 13 formed between the main surface 11 and the end face 12, and an offset portion, at the periphery of the main surface 11, raised or lowered with respect to a flat surface, other than the periphery, of the main surface 11, and characterized in that the magnitude of the offset portion is approximately uniform over the entire circumference of the glass substrate 10.Type: ApplicationFiled: November 24, 2014Publication date: April 23, 2015Applicants: HOYA GLASS DISK (Thailand) LTD., HOYA CORPORATIONInventors: Toshio TAKIZAWA, Kraisorn PHANDON, Kenichi NISHIMORE
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Patent number: 8986859Abstract: It is an object to provide a magnetic disk substrate highly reliable to prevent the occurrence of crash failure even if a magnetic disk is rotated at high speed, and suitable for a hard disk that starts and stops by the load/unload method, and a magnetic disk using such a substrate. The representative structure of a magnetic disk substrate is a disk-shaped glass substrate 10 having a generally flat main surface 11, an end face 12, a chamfered face 13 formed between the main surface 11 and the end face 12, and an offset portion, at the periphery of the main surface 11, raised or lowered with respect to a flat surface, other than the periphery, of the main surface 11, and characterized in that the magnitude of the offset portion is approximately uniform over the entire circumference of the glass substrate 10.Type: GrantFiled: July 9, 2012Date of Patent: March 24, 2015Assignees: Hoya Corporation, Hoya Glass Disk (Thailand) Ltd.Inventors: Toshio Takizawa, Kraisorn Phandon, Kenichi Nishimori
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Patent number: 8895165Abstract: Provided is a method of manufacturing a magnetic disk glass substrate, wherein, in a main surface polishing process, main surface polishing is applied to one of main surfaces of a glass substrate so that the one main surface has a predetermined arithmetic mean roughness, and main surface polishing is applied to the other main surface of the glass substrate so that the other main surface has a roughness which is higher than the arithmetic mean roughness (Ra) of the one main surface and which is low enough to prevent a component forming the magnetic disk glass substrate from being eluted from the other main surface.Type: GrantFiled: September 2, 2009Date of Patent: November 25, 2014Assignees: Hoya Corporation, Hoya Glass Disk (Thailand) Ltd.Inventors: Kenichi Nishimori, Tadashi Tomonaga
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Patent number: 8640497Abstract: To provide a magnetic-disk glass substrate manufacturing method that can reduce the inner diameter dimensional error.Type: GrantFiled: January 24, 2008Date of Patent: February 4, 2014Assignees: Hoya Corporation, Hoya Glass Disk (thailand) Ltd.Inventors: Ryuuichi Kashima, Hideki Isono, Shinji Eda, Tomotaka Yokoyama, Tadashi Tomonaga, Kraisorn Phandon, Weeraphan Yayod
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Patent number: 8567044Abstract: A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.Type: GrantFiled: August 31, 2011Date of Patent: October 29, 2013Assignees: Hoya Corporation, Hoya Glass Disk (thailand) Ltd.Inventors: Hiroshi Takeda, Ken-ichi Nishimori, Tomotaka Yokoyama, Tadashi Tomonaga
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Publication number: 20130089754Abstract: With regard to a glass substrate 1 according to the present invention, a value of an amendment concentricity AC that has taken into consideration Sk and/or Ku calculated from a shape profile over the whole circumference of an inside hole, or the skewness is within a predetermined range. The glass substrate for a magnetic recording medium can stably read servo information including track information stored on a magnetic disk when the glass substrate is used for an HDD.Type: ApplicationFiled: October 4, 2012Publication date: April 11, 2013Applicants: HOYA GLASS DISK (THAILAND) LTD., HOYA CORPORATIONInventors: Hoya Corporation, Hoya Glass Disk (Thailand) Ltd.
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Publication number: 20120276416Abstract: It is an object to provide a magnetic disk substrate highly reliable to prevent the occurrence of crash failure even if a magnetic disk is rotated at high speed, and suitable for a hard disk that starts and stops by the load/unload method, and a magnetic disk using such a substrate. The representative structure of a magnetic disk substrate according to this invention is a disk-shaped glass substrate 10 having a generally flat main surface 11, an end face 12, a chamfered face 13 formed between the main surface 11 and the end face 12, and an offset portion, at the periphery of the main surface 11, raised or lowered with respect to a flat surface, other than the periphery, of the main surface 11, and characterized in that the magnitude of the offset portion is approximately uniform over the entire circumference of the glass substrate 10.Type: ApplicationFiled: July 9, 2012Publication date: November 1, 2012Applicants: HOYA GLASS DISK (THAILAND) LTD., HOYA CORPORATIONInventors: Toshio TAKIZAWA, Kraisorn PHANDON, Kenichi NISHIMORI
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Patent number: 8241768Abstract: It is an object to provide a magnetic disk substrate highly reliable to prevent the occurrence of crash failure even if a magnetic disk is rotated at high speed, and suitable for a hard disk that starts and stops by the load/unload method, and a magnetic disk using such a substrate. The representative structure of a magnetic disk substrate according to this invention is a disk-shaped glass substrate 10 having a generally flat main surface 11, an end face 12, a chamfered face 13 formed between the main surface 11 and the end face 12, and an offset portion, at the periphery of the main surface 11, raised or lowered with respect to a flat surface, other than the periphery, of the main surface 11, and characterized in that the magnitude of the offset portion is approximately uniform over the entire circumference of the glass substrate 10.Type: GrantFiled: February 19, 2008Date of Patent: August 14, 2012Assignees: Hoya Corporation, Hoya Glass Disk (thailand) Ltd.Inventors: Toshio Takizawa, Kraisom Phandon, Kenichi Nishimori
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Publication number: 20110308073Abstract: A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.Type: ApplicationFiled: August 31, 2011Publication date: December 22, 2011Applicants: HOYA GLASS DISK (thailand) LTD., HOYA CORPORATIONInventors: Hiroshi TAKEDA, Ken-ichi Nishimori, Tomotaka Yokoyama, Tadashi Tomonaga
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Patent number: 8033008Abstract: A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.Type: GrantFiled: January 15, 2008Date of Patent: October 11, 2011Assignees: Hoya Corporation, Hoya Glass Disk (thailand) Ltd.Inventors: Hiroshi Takeda, Ken-ichi Nishimori, Tomotaka Yokoyama, Tadashi Tomonaga
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Publication number: 20110165439Abstract: Provided is a method of manufacturing a magnetic disk glass substrate, wherein, in a main surface polishing process, main surface polishing is applied to one of main surfaces of a glass substrate so that the one main surface has a predetermined arithmetic mean roughness, and main surface polishing is applied to the other main surface of the glass substrate so that the other main surface has a roughness which is higher than the arithmetic mean roughness (Ra) of the one main surface and which is low enough to prevent a component forming the magnetic disk glass substrate from being eluted from the other main surface.Type: ApplicationFiled: September 2, 2009Publication date: July 7, 2011Applicants: HOYA CORPORATION, HOYA GLASS DISK (THAILAND) LTD.Inventors: Kenichi Nishimori, Tadashi Tomonaga
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Publication number: 20100226042Abstract: NG surface information obtained in a defect inspecting step of a magnetic disk substrate is depicted on the magnetic disc substrate, so that the information can be discriminated at a succeeding film depositing step.Type: ApplicationFiled: September 1, 2008Publication date: September 9, 2010Applicants: HOYA CORPORATION, HOYA GLASS DISK (Thailand ) LTD.Inventors: Kenichi Nishimori, Tadashi Tomonaga