Patents by Inventor Kara Yoshida
Kara Yoshida 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: 8007877Abstract: To provide a liquid crystal optical modulation element which is excellent in durability against blue laser and which can maintain the characteristics for a long period of time. A liquid crystal optical modulation element to modulate a laser beam having a wavelength of at most 500 nm, which comprises a layer of a polymer liquid crystal composition sandwiched between a pair of transparent substrates facing each other, characterized in that each of the pair of transparent substrates has an alignment film on the surface which faces the other transparent substrate, and the polymer liquid crystal composition is a polymer liquid crystal containing a hindered amine compound and a hindered phenol compound.Type: GrantFiled: October 22, 2010Date of Patent: August 30, 2011Assignee: Asahi Glass Company, LimitedInventors: Kara Yoshida, Yuriko Kaida, Hiromichi Nagayama, Hiroshi Kumai
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Patent number: 7986606Abstract: An optical head device having a broadband phase plate of transforming at least three linearly polarized light beams having different wavelengths into circularly polarized light beams, is obtained. A broadband phase plate comprising two phase plates 9A and 9B laminated with e.g. an adhesive agent so that their optical axes are crossed, wherein provided that wavelengths of linearly polarized incident light beams are ?1, ?2 and ?3 (?1<?2<?3), at least one or both of the two phase plates has such a phase difference characteristics that a ratio R(?1)/R(?3) and a ratio R(?2)/R(?3) between retardation values of the wavelengths are smaller than 1 and R(?1)/R(?3) is smaller than R(?2)/R(?3), is integrated in the optical head device.Type: GrantFiled: March 14, 2007Date of Patent: July 26, 2011Assignee: Asahi Glass Company, LimitedInventors: Nobuhiko Takeshita, Tomoki Gunjima, Kara Yoshida
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Patent number: 7927186Abstract: In the production of a glass substrate for magnetic disk, the present invention provides a method for producing a glass substrate for magnetic disk including a step of polishing a main surface of a circular glass substrate using a polishing pad made of a foamed resin while feeding a polishing liquid containing an abrasive, in which a polishing pad made of a foamed resin having an international rubber hardness of 45 IRHD or less, the hardness being measured at a dry state before contact with a slurry by the M method defined in JIS K6253, is used as a starting polishing pad and polishing is started after a polishing surface of the starting polishing pad is subjected to a dressing treatment to adjust the pad so that an open pore area ratio is 8% or more and an average circle equivalent diameter of open pores is 10 ?m or more, in order to suppress an increase in roll-off in the polishing step of the main surface of the circular glass plate.Type: GrantFiled: July 16, 2009Date of Patent: April 19, 2011Assignee: Asahi Glass Company, LimitedInventors: Mizuho Ishida, Kara Yoshida
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Publication number: 20110037910Abstract: To provide a liquid crystal optical modulation element which is excellent in durability against blue laser and which can maintain the characteristics for a long period of time. A liquid crystal optical modulation element to modulate a laser beam having a wavelength of at most 500 nm, which comprises a layer of a polymer liquid crystal composition sandwiched between a pair of transparent substrates facing each other, characterized in that each of the pair of transparent substrates has an alignment film on the surface which faces the other transparent substrate, and the polymer liquid crystal composition is a polymer liquid crystal containing a hindered amine compound and a hindered phenol compound.Type: ApplicationFiled: October 22, 2010Publication date: February 17, 2011Applicant: Asahi Glass Company, LimitedInventors: Kara YOSHIDA, Yuriko Kaida, Hiromichi Nagayama, Hiroshi Kumai
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Patent number: 7846515Abstract: To provide a liquid crystal optical modulation element which is excellent in durability against blue laser and which can maintain the characteristics for a long period of time. A liquid crystal optical modulation element to modulate a laser beam having a wavelength of at most 500 nm, which comprises a layer of a polymer liquid crystal composition sandwiched between a pair of transparent substrates facing each other, characterized in that each of the pair of transparent substrates has an alignment film on the surface which faces the other transparent substrate, and the polymer liquid crystal composition is a polymer liquid crystal containing a hindered amine compound and a hindered phenol compound.Type: GrantFiled: February 26, 2010Date of Patent: December 7, 2010Assignee: Asahi Glass Company, LimitedInventors: Kara Yoshida, Yuriko Kaida, Hiromichi Nagayama, Hiroshi Kumai
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Patent number: 7820250Abstract: To provide a liquid crystal optical modulation element which is excellent in durability against blue laser and which can maintain the characteristics for a long period of time. A liquid crystal optical modulation element to modulate a laser beam having a wavelength of at most 500 nm, which comprises a layer of a polymer liquid crystal composition sandwiched between a pair of transparent substrates facing each other, characterized in that each of the pair of transparent substrates has an alignment film on the surface which faces the other transparent substrate, and the polymer liquid crystal composition is a polymer liquid crystal containing a hindered amine compound and a hindered phenol compound.Type: GrantFiled: April 18, 2008Date of Patent: October 26, 2010Assignee: Asahi Glass Company, LimitedInventors: Kara Yoshida, Yuriko Kaida, Hiromichi Nagayama, Hiroshi Kumai
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Publication number: 20100149950Abstract: To provide a liquid crystal optical modulation element which is excellent in durability against blue laser and which can maintain the characteristics for a long period of time. A liquid crystal optical modulation element to modulate a laser beam having a wavelength of at most 500 nm, which comprises a layer of a polymer liquid crystal composition sandwiched between a pair of transparent substrates facing each other, characterized in that each of the pair of transparent substrates has an alignment film on the surface which faces the other transparent substrate, and the polymer liquid crystal composition is a polymer liquid crystal containing a hindered amine compound and a hindered phenol compound.Type: ApplicationFiled: February 26, 2010Publication date: June 17, 2010Applicant: Asahi Glass Company, LimitedInventors: Kara Yoshida, Yuriko Kaida, Hiromichi Nagayama, Hiroshi Kumai
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Patent number: 7618690Abstract: A liquid crystal compound represented by the formula CH2?CR1—COO-(L)k-E1-E2-E3-E4-R2 wherein R1: a hydrogen atom or a methyl group; R2: a C1-8 alkyl group; k: 0 or 1; L: —(CH2)pO— or —(CH2)q— (wherein each of p and q which are independent of each other, is an integer of from 2 to 8); E1: a 1,4-phenylene group; E2, E3, E4: each independently a 1,4-phenylene group or a trans-1,4-cyclohexylene group and at least one of E2 and E3 is a trans-1,4-cyclohexylene group, provided that the 1,4-phenylene group and trans-1,4-cyclohexylene group in E1 to E4, may be such that a hydrogen atom bonded to a carbon atom in each group may be substituted by a fluorine atom, a chlorine atom or a methyl group. To provide a novel liquid crystal compound for preparing an optical element which can exhibit a proper Rd value depending upon usable wavelength and application and which is excellent in durability against a blue laser beam.Type: GrantFiled: April 17, 2008Date of Patent: November 17, 2009Assignee: Asahi Glass Company, LimitedInventors: Hiromichi Nagayama, Yuriko Kaida, Kara Yoshida
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Publication number: 20090275268Abstract: In the production of a glass substrate for magnetic disk, the present invention provides a method for producing a glass substrate for magnetic disk including a step of polishing a main surface of a circular glass substrate using a polishing pad made of a foamed resin while feeding a polishing liquid containing an abrasive, in which a polishing pad made of a foamed resin having an international rubber hardness of 45 IRHD or less, the hardness being measured at a dry state before contact with a slurry by the M method defined in JIS K6253, is used as a starting polishing pad and polishing is started after a polishing surface of the starting polishing pad is subjected to a dressing treatment to adjust the pad so that an open pore area ratio is 8% or more and an average circle equivalent diameter of open pores is 10 ?m or more, in order to suppress an increase in roll-off in the polishing step of the main surface of the circular glass plate.Type: ApplicationFiled: July 16, 2009Publication date: November 5, 2009Applicant: Asahi Glass Company, LimitedInventors: Mizuho Ishida, Kara Yoshida
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Publication number: 20090239450Abstract: In the production of a glass substrate for magnetic disks, in a step of polishing a main surface of a circular glass plate, roll-off is reduced without reducing the polishing rate. The process comprises a step of polishing a main surface of a circular glass plate by using an acidic polishing fluid containing colloidal silica or fumed silica, and a water-soluble polymer having at least one member selected from a group consisting of a carboxylic acid group, a carboxylate group, a sulfonic acid group and a sulfonate group, bonded to its main chain, or an acidic polishing fluid containing 100 parts by mass of colloidal silica or fumed silica, and from 0.02 to 0.1 part by mass of a surfactant having a sulfonic acid group.Type: ApplicationFiled: June 3, 2009Publication date: September 24, 2009Applicant: ASAHI GLASS COMPANY LIMITEDInventors: Mizuho ISHIDA, Kara Yoshida, Hiroshi Usui
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Patent number: 7534370Abstract: To provide optical elements such as a phase plate suitably used in a broadband range and a polarizing diffraction element excellent in diffraction efficiency, a polymerizable liquid crystal composition to be used for them, and an optical head device using them.Type: GrantFiled: October 15, 2007Date of Patent: May 19, 2009Assignee: Asahi Glass Company, LimitedInventors: Kara Yoshida, Tomoki Gunjima, Nobuhiko Takeshita, Yuzuru Tanabe, Hiroki Hotaka, Hiromasa Sato
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Publication number: 20080231788Abstract: To provide a liquid crystal optical modulation element which is excellent in durability against blue laser and which can maintain the characteristics for a long period of time. A liquid crystal optical modulation element to modulate a laser beam having a wavelength of at most 500 nm, which comprises a layer of a polymer liquid crystal composition sandwiched between a pair of transparent substrates facing each other, characterized in that each of the pair of transparent substrates has an alignment film on the surface which faces the other transparent substrate, and the polymer liquid crystal composition is a polymer liquid crystal containing a hindered amine compound and a hindered phenol compound.Type: ApplicationFiled: April 18, 2008Publication date: September 25, 2008Applicant: Asahi Glass Company, LimitedInventors: Kara YOSHIDA, Hiromichi Nagayama
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Publication number: 20080204650Abstract: To provide a novel liquid crystal compound for preparing, for example, an optical element which can exhibit a proper Rd value depending upon usable wavelength and application and which is excellent in durability against a blue laser beam. A liquid crystal compound represented by the formula CH2?CR1—COO-(L)k-E1-E2-E3-E4-R2 wherein R1: a hydrogen atom or a methyl group; R2: a C1-8 alkyl group; k:0 or 1; L: —(CH2)pO— or —(CH2)q— (wherein each of p and q which are independent of each other, is an integer of from 2 to 8); E1: a 1,4-phenylene group; E2, E3, E4: each independently a 1,4-pheneylene group or a trans-1,4-cyclohexylene group and at least one of E2 and E3 is a trans-1,4-cyclohexylene group, provided that the 1,4-phenylene group and trans-1,4-cyclohexylene group in E1 to E4, may be such that a hydrogen atom bonded to a carbon atom in each group may be substituted by a fluorine atom, a chlorine atom or a methyl group.Type: ApplicationFiled: April 17, 2008Publication date: August 28, 2008Applicant: ASAHI GLASS COMPANY LIMITEDInventors: Hiromichi Nagayama, Yuriko Kaida, Kara Yoshida
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Publication number: 20080048149Abstract: To provide optical elements such as a phase plate suitably used in a broadband range and a polarizing diffraction element excellent in diffraction efficiency, a polymerizable liquid crystal composition to be used for them, and an optical head device using them.Type: ApplicationFiled: October 15, 2007Publication date: February 28, 2008Applicant: ASAHI GLASS COMPANY, LIMITEDInventors: Kara YOSHIDA, Tomoki GUNJIMA, Nobuhiko TAKESHITA, Yuzuru TANABE, Hiroki HOTAKA, Hiromasa SATO
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Publication number: 20070159932Abstract: An optical head device having a broadband phase plate of transforming at least three linearly polarized light beams having different wavelengths into circularly polarized light beams, is obtained. A broadband phase plate comprising two phase plates 9A and 9B laminated with e.g. an adhesive agent so that their optical axes are crossed, wherein provided that wavelengths of linearly polarized incident light beams are ?1, ?2 and ?3 (?1<?2<?3), at least one or both of the two phase plates has such a phase difference characteristics that a ratio R(?1)/R(?3) and a ratio R(?2)/R(?3) between retardation values of the wavelengths are smaller than 1 and R(?1)/R(?3) is smaller than R(?2)/R(?3), is integrated in the optical head device.Type: ApplicationFiled: March 14, 2007Publication date: July 12, 2007Applicant: ASAHI GLASS COMPANY, LIMITEDInventors: Nobuhiko Takeshita, Tomoki Gunjima, Kara Yoshida