Patents by Inventor Hirofumi TOKUNAGA

Hirofumi TOKUNAGA 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).

  • Publication number: 20210024403
    Abstract: An alkali-free glass has a strain point of 650° C. or more, an average coefficient of thermal expansion at 50 to 350° C. of from 30×10?7 to 45×10?7/° C., and a temperature T2 at which a glass viscosity reaches 102 dPa·s of from 1,500 to 1,800° C. The alkali-free glass contains, as represented by mol % based on oxides, SiO2: from 62 to 70%, Al2O3: from 9 to 16% B2O3: from 0 to 12%, MgO: from 3 to 10%, CaO: from 4 to 12%, SrO: from 0 to 6%, and Fe2O3: from 0.001 to 0.04%, provided that MgO+CaO+SrO+BaO is from 12 to 25%. The alkali-free glass has a ?-OH value of from 0.35 to 0.85/mm.
    Type: Application
    Filed: October 14, 2020
    Publication date: January 28, 2021
    Applicant: AGC Inc.
    Inventors: Hirofumi TOKUNAGA, Kazutaka ONO, Motoyuki HIROSE
  • Publication number: 20200407265
    Abstract: An alkali free glass has an average coefficient of thermal expansion at 50 to 350° C. of 30×10?7 to 43×10?7/° C., a Young's modulus of 88 GPa or more, a strain point of 650 to 725° C., a temperature T4 at which a viscosity reaches 104 dPa·s of 1,290° C. or lower, a glass surface devitrification temperature (Tc) of T4+20° C. or lower, and a temperature T2 at which the viscosity reaches 102 dPa·s of 1,680° C. or lower. The alkali free glass contains, as represented by mol % based on oxides, 62 to 67% of SiO2, 12.5 to 16.5% of Al2O3, 0 to 3% of B2O3, 8 to 13% of MgO, 6 to 12% of CaO, 0.5 to 4% of SrO, and 0 to 0.5% of BaO. MgO+CaO+SrO+BaO is 18 to 22%, and MgO/CaO is 0.8 to 1.33.
    Type: Application
    Filed: September 11, 2020
    Publication date: December 31, 2020
    Applicant: AGC Inc.
    Inventors: Hirofumi TOKUNAGA, Kazutaka ONO
  • Publication number: 20200407264
    Abstract: A glass has a density of 2.60 g/cm3 or lower, a Young's modulus of 88 GPa or more, a strain point of 650 to 720° C., a temperature T4 at which a glass viscosity reaches 104 dPa·s of 1,320° C. or lower, a glass surface devitrification temperature (Tc) of T4+20° C. or lower, and an average coefficient of thermal expansion of 30×10?7 to 43×10?7/° C. at 50 to 350° C. The glass contains, as represented by mol % based on oxides, 50 to 80% of SiO2, 8 to 20% of Al2O3, 0 to 0.5% in total of at least one kind of alkali metal oxide selected from the group consisting of Li2O, Na2O and K2O, and 0 to 1% of P2O5.
    Type: Application
    Filed: September 10, 2020
    Publication date: December 31, 2020
    Applicant: AGC INC.
    Inventors: Hirofumi TOKUNAGA, Kazutaka ONO
  • Patent number: 10822264
    Abstract: The present invention relates to an alkali-free glass substrate, in which when two arbitrary sites in one main surface thereof are selected, an absolute value of a difference between a thermal shrinkage ratio in an arbitrary direction at one site and a thermal shrinkage ratio in a direction orthogonal to the arbitrary direction at another site is 2 ppm or less, provided that the thermal shrinkage ratio is calculated by measuring a deformation amount in a measuring direction of the glass substrate between before and after a heat treatment of raising a temperature from normal temperature to 600° C. at 100° C./hour, holding the glass substrate at 600° C. for 80 minutes, and lowering the temperature from 600° C. to normal temperature at 100° C./hour.
    Type: Grant
    Filed: March 14, 2017
    Date of Patent: November 3, 2020
    Assignee: AGC INC.
    Inventors: Tetsushi Takiguchi, Shunji Inoue, Kazutaka Ono, Hirofumi Tokunaga, Jun Akiyama, Yasumasa Kato, Taketoshi Taniguchi
  • Patent number: 10730786
    Abstract: The present invention relates to an alkali-free glass and a method for producing the same. More specifically, the present invention relates to an alkali-free glass suitable as a glass for substrates of various displays such as liquid crystal display, and a method for producing the same. According to the present invention, an alkali-free glass suitable as a glass for display substrates, in which inclusion of bubbles is greatly reduced by virtue of containing a refining agent and suppressing the stirring reboil, is obtained.
    Type: Grant
    Filed: April 24, 2019
    Date of Patent: August 4, 2020
    Assignee: AGC INC.
    Inventors: Hirofumi Tokunaga, Kazutaka Ono, Motoyuki Hirose
  • Publication number: 20190248697
    Abstract: The present invention relates to an alkali-free glass and a method for producing the same. More specifically, the present invention relates to an alkali-free glass suitable as a glass for substrates of various displays such as liquid crystal display, and a method for producing the same. According to the present invention, an alkali-free glass suitable as a glass for display substrates, in which inclusion of bubbles is greatly reduced by virtue of containing a refining agent and suppressing the stirring reboil, is obtained.
    Type: Application
    Filed: April 24, 2019
    Publication date: August 15, 2019
    Applicant: AGC Inc.
    Inventors: Hirofumi TOKUNAGA, Kazutaka Ono, Motoyuki Hirose
  • Publication number: 20190185368
    Abstract: To provide an alkali-free glass, of which the compaction is low, the strain point is high, and the ultraviolet transmittance is high, and which is easy to melt. An alkali-free glass, which comprises, as represented by mol % based on oxides, SiO2 from 65 to 75, Al2O3 from 9 to 15, B2O3 from 0 to 3, MgO from 0 to 12, CaO from 0 to 8, SrO from 0 to 6, and BaO from 0 to 5, wherein MgO+CaO+SrO+BaO is from 12 to 22, and 4.84[Fe2O3]+5.65[Na2O]+4.03[K2O]+4.55[SnO2] is at most 0.55, and of which the compaction is at most 80 ppm.
    Type: Application
    Filed: February 22, 2019
    Publication date: June 20, 2019
    Applicant: AGC Inc.
    Inventors: Hirofumi TOKUNAGA, Kazutaka ONO, Motoyuki HIROSE
  • Publication number: 20190047899
    Abstract: To provide an alkali-free glass having a high specific elastic modulus, a suitable strain point, a low density, a not too low thermal expansion coefficient, a good clarity and a good solubility. An alkali-free glass, which comprises, as represented by mol % based on oxides, SiO2: 62 to 70%, Al2O3: 11 to 14%, B2O3: 3 to 6%, MgO: 7 to 10%, CaO: 3 to 9%, SrO: 1 to 5% and BaO: 0 to 1%, wherein [SiO2]+0.7[Al2O3]+1.2[B2O3]+0.5[MgO]+0.4[CaO]?0.25[SrO]?0.88[BaO] is at least 85, [SiO2]+0.45[Al2O3]+0.21[B2O3]?0.042[MgO]+0.042[CaO]+0.15[SrO]+0.38[BaO] is from 72 to 75, 0.4[SiO2]+0.4[Al2O3]+0.25[B2O3]?0.7[MgO]?0.88[CaO]?1.4[SrO]?1.7[BaO] is at most 19, the specific modulus is at least 32 MN·m/kg, the strain point is from 690 to 710° C., the density is at most 2.54 g/cm3, the average thermal expansion coefficient at from 50 to 350° C. is at least 35×10?7/° C., and the temperature T2 at which the glass viscosity reaches 102 dPa·s is from 1,610 to 1,680° C.
    Type: Application
    Filed: October 16, 2018
    Publication date: February 14, 2019
    Applicant: AGC Inc.
    Inventors: Hirofumi TOKUNAGA, Kazutaka ONO
  • Patent number: 9963379
    Abstract: The present invention relates to an alkali-free glass substrate, having a strain point of 680° C. or higher, a Young's modulus of 78 GPa or greater, an UV transmittance at a wavelength of 300 nm of from 40% to 85% in terms of 0.5 mm thickness, an in-plane distribution of the UV transmittance at a wavelength of 300 nm in a G6-sized substrate of 1% or less in terms of 0.5 mm thickness, an average cooling rate around the glass transition point obtained according to a rate cooling method of 400° C./min or lower, and an in-plane distribution of the average cooling rate of 40° C./min or less.
    Type: Grant
    Filed: May 25, 2017
    Date of Patent: May 8, 2018
    Assignee: ASAHI GLASS COMPANY, LIMITED
    Inventors: Hirofumi Tokunaga, Akio Koike, Masaya Kunigita
  • Patent number: 9902645
    Abstract: Provided is a non-alkali glass having a strain point of 680° C. or higher, having an average thermal expansion coefficient of from 30×10?7/° C. to 45×10?7/° C. at from 50° C. to 350° C., containing, indicated by mass % on the basis of oxides: SiO2: 54% to 66%, Al2O3: 10% to 27%, B2O3: 0.2% to 5.5%, MgO: 0% to 10%, CaO: 0% to 15%, SrO: 0% to 15%, BaO: 0% to 15%, and MgO+CaO+SrO+BaO: 8% to 25%, containing 600 mass ppm or less of Na2O, and satisfying a mass ratio (Na2O/B2O3) between Na2O and B2O3 being from 0.001 to 0.3.
    Type: Grant
    Filed: April 18, 2017
    Date of Patent: February 27, 2018
    Assignee: ASAHI GLASS COMPANY, LIMITED
    Inventors: Kazutaka Ono, Hirofumi Tokunaga, Jun Akiyama
  • Publication number: 20170267572
    Abstract: The present invention relates to an alkali-free glass substrate, in which when two arbitrary sites in one main surface thereof are selected, an absolute value of a difference between a thermal shrinkage ratio in an arbitrary direction at one site and a thermal shrinkage ratio in a direction orthogonal to the arbitrary direction at another site is 2 ppm or less, provided that the thermal shrinkage ratio is calculated by measuring a deformation amount in a measuring direction of the glass substrate between before and after a heat treatment of raising a temperature from normal temperature to 600° C. at 100° C./hour, holding the glass substrate at 600° C. for 80 minutes, and lowering the temperature from 600° C. to normal temperature at 100° C./hour.
    Type: Application
    Filed: March 14, 2017
    Publication date: September 21, 2017
    Applicant: ASAHI GLASS COMPANY, LIMITED
    Inventors: Tetsushi TAKIGUCHI, Shunji INOUE, Kazutaka ONO, Hirofumi TOKUNAGA, Jun AKIYAMA, Yasumasa KATO, Taketoshi TANIGUCHI
  • Publication number: 20170260085
    Abstract: The present invention relates to an alkali-free glass substrate, having a strain point of 680° C. or higher, a Young's modulus of 78 GPa or greater, an UV transmittance at a wavelength of 300 nm of from 40% to 85% in terms of 0.5 mm thickness, an in-plane distribution of the UV transmittance at a wavelength of 300 nm in a G6-sized substrate of 1% or less in terms of 0.5 mm thickness, an average cooling rate around the glass transition point obtained according to a rate cooling method of 400° C./min or lower, and an in-plane distribution of the average cooling rate of 40° C./min or less.
    Type: Application
    Filed: May 25, 2017
    Publication date: September 14, 2017
    Applicant: ASAHI GLASS COMPANY, LIMITED
    Inventors: Hirofumi TOKUNAGA, Akio KOIKE, Masaya KUNIGITA
  • Publication number: 20170217826
    Abstract: Provided is a non-alkali glass having a strain point of 680° C. or higher, having an average thermal expansion coefficient of from 30×10?7/° C. to 45×10?7/° C. at from 50° C. to 350° C., containing, indicated by mass % on the basis of oxides: SiO2: 54% to 66%, Al2O3: 10% to 27%, B2O3: 0.2% to 5.5%, MgO: 0% to 10%, CaO: 0% to 15%, SrO: 0% to 15%, BaO: 0% to 15%, and MgO+CaO+SrO+BaO: 8% to 25%, containing 600 mass ppm or less of Na2O, and satisfying a mass ratio (Na2O/B2O3) between Na2O and B2O3 being from 0.001 to 0.3.
    Type: Application
    Filed: April 18, 2017
    Publication date: August 3, 2017
    Applicant: ASAHI GLASS COMPANY, LIMITED
    Inventors: Kazutaka ONO, Hirofumi Tokunaga, Jun Akiyama
  • Patent number: 9708211
    Abstract: The present invention relates to an alkali-free glass substrate, having a strain point of 680° C. or higher, a Young's modulus of 78 GPa or greater, an UV transmittance at a wavelength of 300 nm of from 40% to 85% in terms of 0.5 mm thickness, an in-plane distribution of the UV transmittance at a wavelength of 300 nm in a G6-sized substrate of 1% or less in terms of 0.5 mm thickness, an average cooling rate around the glass transition point obtained according to a rate cooling method of 400° C./min or lower, and an in-plane distribution of the average cooling rate of 40° C./min or less.
    Type: Grant
    Filed: October 22, 2015
    Date of Patent: July 18, 2017
    Assignee: ASAHI GLASS COMPANY, LIMITED
    Inventors: Hirofumi Tokunaga, Akio Koike, Masaya Kunigita
  • Patent number: 9663395
    Abstract: The present invention relates to an alkali-free glass having a strain point of from 680 to 735° C., an average thermal expansion coefficient at from 50 to 350° C. of from 30×10?7 to 43×10?7/° C., and a specific gravity of 2.60 or less, and containing, indicated by mol % on the basis of oxides, SiO2 65 to 69%, Al2O3 11.5 to 14%, B2O3 3 to 6.5%, MgO 1 to 5%, CaO 7.5 to 12%, SrO 0 to 1%, BaO 0.5 to 6%, and ZrO2 0 to 2%.
    Type: Grant
    Filed: December 8, 2014
    Date of Patent: May 30, 2017
    Assignee: ASAHI GLASS COMPANY, LIMITED
    Inventors: Hirofumi Tokunaga, Manabu Nishizawa, Akio Koike
  • Publication number: 20170066682
    Abstract: The present invention relates to an alkali-free float sheet glass having a glass transition point of from 730 to 850° C. and a temperature T4 of from 1220 to 1350° C., and containing, indicated by mass % on the basis of oxides: SiO2: 57 to 65%, Al2O3: 14 to 23%, B2O3: 0 to 5.5%, MgO: 1 to 8.5%, CaO: 3 to 12%, SrO: 0 to 10%, and BaO: 0 to 5%, satisfying MgO+CaO+SrO+BaO of from 12 to 23%, containing F in an amount of from 0.1 to 0.35 mass %, containing Cu in an amount of from 0.3 to 3 mass ppm, containing Cl in an amount of from 0 to 0.05 mass %, and satisfying a ratio f1/f2 of from 0.05 to 0.5.
    Type: Application
    Filed: November 21, 2016
    Publication date: March 9, 2017
    Applicant: ASAHI GLASS COMPANY, LIMITED
    Inventors: Shiro TANII, Kazutaka ONO, Hirofumi TOKUNAGA, Yosuke INAI, Daisuke KOBAYASHI
  • Patent number: 9540273
    Abstract: The present invention relates to a non-alkali glass having a strain point of from 710° C. to lower than 725° C., an average thermal expansion coefficient at from 50 to 300° C. of from 30×10?7 to 43×10?7/° C., a temperature T2 at which glass viscosity reaches 102 dPa·s of 1710° C. or lower, a temperature T4 at which the glass viscosity reaches 104 dPa·s of 1320° C. or lower, and containing, indicated by mol % on the basis of oxides, SiO2 66 to 70, Al2O3 12 to 14, B2O3 exceeding 0 to 1.5, MgO exceeding 9.5 to 13 (or 5 to 9.5), CaO 4 to 9 (or 4 to 11), SrO 0.5 to 4.5, BaO 0 to 0.5 and ZrO 0 to 2.
    Type: Grant
    Filed: November 17, 2015
    Date of Patent: January 10, 2017
    Assignee: ASAHI GLASS COMPANY, LIMITED
    Inventors: Hirofumi Tokunaga, Tomoyuki Tsujimura, Manabu Nishizawa, Akio Koike
  • Patent number: 9505650
    Abstract: The present invention relates to a non-alkali glass substrate, having a strain point of 685° C. or higher and 750° C. or lower, an average thermal expansion coefficient at 50 to 350° C. of from 35×10?7 to 43×10?7/° C., a specific gravity of from 2.50 to 2.80, a photoelastic constant of 25 nm/MPa/cm or more and less than 29 nm/MPa/cm, and a temperature (T4) at which viscosity reaches 104 dPa·s of 1,250° C. or higher and lower than 1,350° C., and having a prescribed composition.
    Type: Grant
    Filed: December 2, 2013
    Date of Patent: November 29, 2016
    Assignee: ASAHI GLASS COMPANY, LIMITED
    Inventors: Manabu Nishizawa, Akio Koike, Hirofumi Tokunaga
  • Patent number: 9382152
    Abstract: The present invention relates to a non-alkali glass having a strain point of from 710° C. to lower than 725° C., an average thermal expansion coefficient at from 50 to 300° C. of from 30×10?7 to 43×10?7/° C., a temperature T2 at which glass viscosity reaches 102 dPa·s of 1710° C. or lower, a temperature T4 at which the glass viscosity reaches 104 dPd·s of 1320° C. or lower, and containing, indicated by mol % on the basis of oxides, SiO2 66 to 70, Al2O3 12 to 14, B2O3 exceeding 0 to 1.5, MgO exceeding 9.5 to 13 (or 5 to 9.5), CaO 4 to 9 (or 4 to 11), SrO 0.5 to 4.5, BaO 0 to 0.5 and ZrO 0 to 2.
    Type: Grant
    Filed: October 27, 2014
    Date of Patent: July 5, 2016
    Assignee: ASAHI GLASS COMPANY, LIMITED
    Inventors: Hirofumi Tokunaga, Tomoyuki Tsujimura, Manabu Nishizawa, Akio Koike
  • Publication number: 20160068427
    Abstract: The present invention relates to a non-alkali glass having a strain point of from 710° C. to lower than 725° C., an average thermal expansion coefficient at from 50 to 300° C. of from 30×10?7 to 43×10?7/° C., a temperature T2 at which glass viscosity reaches 102 dPa·s of 1710° C. or lower, a temperature T4 at which the glass viscosity reaches 104 dPa·s of 1320° C. or lower, and containing, indicated by mol % on the basis of oxides, SiO2 66 to 70, Al2O3 12 to 14, B2O3 exceeding 0 to 1.5, MgO exceeding 9.5 to 13 (or 5 to 9.5), CaO 4 to 9 (or 4 to 11), SrO 0.5 to 4.5, BaO 0 to 0.5 and ZrO 0 to 2.
    Type: Application
    Filed: November 17, 2015
    Publication date: March 10, 2016
    Applicant: ASAHI GLASS COMPANY, LIMITED
    Inventors: Hirofumi TOKUNAGA, Tomoyuki TSUJIMURA, Manabu NISHIZAWA, Akio KOIKE