Avanstrate Inc.

Hoya Corporation

Satoshi Ami

Akihiro Koyama

Manabu Ichikawa

Kazuaki Hashimoto

Tetsuo Takano

Mikiko Morishita

A substrate for p-Si TFT flat panel displays made of a glass having a high low-temperature-viscosity characteristic temperature and manufactured while avoiding erosion/wear of a melting tank during melting through direct electrical heating. The glass substrate comprises 52-78 mass % of SiO, 3-25 mass % of AlO, 3-15 mass % of BO, 3-20 mass % of RO, wherein RO is total amount of MgO, CaO, SrO, and BaO, 0.01-0.8 mass % of RO, wherein RO is total amount of LiO, NaO, and KO, and 0-0.3 mass % of SbO, and substantially does not comprise AsO, wherein the mass ratio CaO/RO is equal to or greater than 0.65, the mass ratio (SiO+AlO)/BOis in a range of 7-30, and the mass ratio (SiO+AlO)/RO is equal to or greater than 5. A related method involves melting glass raw materials blended to provide the glass composition; a forming step of forming the molten glass into a flat-plate glass; and an annealing step of annealing the flat-plate glass.

Glass substrate for flat panel display and method for manufacturing same

A flat panel display glass substrate according to the present invention includes a glass comprising, as expressed in mol %, 55-80% SiO, 3-20% AlO, 3-15% BO, 3-25% RO (the total amount of MgO, CaO, SrO, and BaO), and substantially no AsO, and SbO. The devitrification temperature of the glass is 1250&#xb0; C. or less. The glass substrate has a heat shrinkage rate of 75 ppm or less. The heat shrinkage rate is calculated from the amount of shrinkage of the glass substrate measured after a heat treatment which is performed at a temperature rising and falling rate of 10&#xb0; C./min and at 550&#xb0; C. for 2 hours by the heat shrinkage rate (ppm)={the amount of shrinkage of the glass substrate after the heat treatment/the length of the glass substrate before the heat treatment}&#xd7;10.

Glass substrate for flat panel display and manufacturing method thereof

The disclosed cover glass is produced by etching a glass substrate that has been formed by a down-drawing process, and chemically strengthening the glass substrate to provide the glass substrate with a compressive-stress layer on the principal surfaces thereof. The glass substrate contains, as components thereof, 50% to 70% by mass of SiO, 5% to 20% by mass of AlO, 6% to 30% by mass of NaO, and 0% to less than 8% by mass of LiO. The glass substrate may also contain 0% to 2.6% by mass of CaO, if necessary. The glass substrate has an etching characteristic in which the etching rate is at least 3.7 &#x3bc;m/minute in an etching environment having a temperature of 22&#xb0; C. and containing hydrogen fluoride with a concentration of 10% by mass.

Cover glass and method for producing cover glass

A glass substrate for p-Si TFT flat panel displays that is composed of a glass comprising 52-78 mass % of SiO, 3-25 mass % of AlO, 3-15 mass % of BO, 3-25 mass % of RO, wherein RO is total amount of MgO, CaO, SrO, and BaO, 0.01-1 mass % of FeO, and 0-0.3 mass % of SbO, and substantially not comprising AsO, the glass having a mass ratio (SiO+AlO)/BOin a range of 7-30 and a mass ratio (SiO+AlO)/RO equal to or greater than 6. A method for manufacturing a glass substrate involves: a melting step of obtaining a molten glass by melting, by employing at least direct electrical heating, glass raw materials blended so as to provide the aforementioned glass composition; a forming step of forming the molten glass into a flat-plate glass; and an annealing step of annealing the flat-plate glass.

A flat panel display glass substrate includes a glass comprising, in mol %, 55-80% SiO, 3-20% AlO, 3-15% BO, and 3-25% RO (the total amount of MgO, CaO, SrO, and BaO). The contents in mol % of SiO, AlO, and BOsatisfy a relationship (SiO+AlO)/(BO)=7.5-17. The strain point of the glass is 665&#xb0; C. or more. The devitrification temperature of the glass is 1250&#xb0; C. or less. The substrate has a heat shrinkage rate of 75 ppm or less. The rate of heat shrinkage is calculated from the amount of shrinkage of the substrate measured after a heat treatment which is performed at a rising and falling temperature rate of 10&#xb0; C./min and at 550&#xb0; C. for 2 hours by the rate of heat shrinkage (ppm)={the amount of shrinkage of the substrate after the heat treatment/the length of the substrate before the heat treatment}&#xd7;10.

Provided are: a glass substrate for p-Si TFT flat panel displays that is composed of a glass having high characteristic temperatures in the low-temperature viscosity range, typified by the strain point and glass transition point, having a small heat shrinkage rate, and being capable of avoiding the occurrence of the problem regarding the erosion/wear of a melting tank at the time of melting through direct electrical heating; and a method for manufacturing same. The present glass substrate is composed of a glass comprising 52-78 mass % of SiO, 3-25 mass % of AlO, 3-15 mass % of BO, 3-25 mass % of RO, wherein RO is total amount of MgO, CaO, SrO, and BaO, 0.01-1 mass % of FeO, and 0-0.3 mass % of SbO, and substantially not comprising AsO, the glass having a mass ratio (SiO+AlO)/BOin a range of 7-30 and a mass ratio (SiO+AlO)/RO equal to or greater than 6. The present method for manufacturing a glass substrate involves: a melting step of obtaining a molten glass by melting, by employing at least direct electrical heating, glass raw materials blended so as to provide the aforementioned glass composition; a forming step of forming the molten glass into a flat-plate glass; and an annealing step of annealing the flat-plate glass.

A flat panel display glass substrate according to the present invention includes a glass comprising, as expressed in mol %, 55-80% SiO, 3-20% AlO, 3-15% BO, 3-25% RO (the total amount of MgO, CaO, SrO, and BaO), and substantially no AsOand SbO. The devitrification temperature of the glass is 1250&#xb0; C. or less. The glass substrate has a heat shrinkage rate of 75 ppm or less. The heat shrinkage rate is calculated from the amount of shrinkage of the glass substrate measured after a heat treatment which is performed at a temperature rising and falling rate of 10&#xb0; C./min and at 550&#xb0; C. for 2 hours by the heat shrinkage rate (ppm)={the amount of shrinkage of the glass substrate after the heat treatment/the length of the glass substrate before the heat treatment}&#xd7;10.

A cover glass having a compressive-stress layer on the principal surfaces thereof, and having a glass composition containing 50% to 70% by mole of SiO, 3% to 20% by mole of AlO, 5% to 25% by mole of NaO, more than 0% by mole and less than or equal to 2.5% by mole of LiO, 0% to 5.5% by mole of KO, and 0% to less than 3% by mole of BO. Also disclosed is a method for producing a cover glass which includes: (i) preparing molten glass by melting a glass raw material; (ii) forming the prepared molten glass into a plate-like shape by a down-draw process and thereby obtaining a glass substrate; and (iii) forming a compressive-stress layer on the surface of the glass substrate.

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Yokkaichi, Japan

Satoshi Ami