Alkali-free glass and liquid crystal display panel

Abstract

The invention provides alkali-free glass which has a strain point no less than 640 DEG C, a thermal expansion coefficient less than 40*10<-7> / DEG C, a density less than 2.60, no white turbidity caused by the buffering of hydrofluoric acid and excellent acid resistance, and provides a liquid crystal display panel. The alkali-free glass comprises, by weight percentage, 58.4 to 66.0% of SiO2, 15.3 to 22.0% of Al2O3, 5.0 to 12.0% of B2O3, 0 to 6.5% of MgO, 0 to 7.0% of CaO, 4.0 to 12.5% of SrO, less than 2.0% of BaO and 9.0 to 18.0% of MgO+CaO+SrO.

Description

technical field [0001] The present invention relates to a float-formable alkali-free glass that does not substantially contain alkali metal oxides and is suitable as a substrate glass for various displays and photomasks, and a liquid crystal display panel using the alkali-free glass. Background technique [0002] Conventionally, various substrate glasses for displays, especially substrate glasses having a metal or oxide thin film formed on the surface, have required the following characteristics. [0003] (1) When an alkali metal oxide is contained, the alkali metal ions diffuse into the thin film and the film properties are deteriorated, so the alkali metal ions are not substantially contained. [0004] (2) Since the glass is exposed to high temperature in the film forming process, it has a high strain point in order to minimize the deformation of the glass and the shrinkage accompanying the stabilization of the structure of the glass. [0005] (3) It has sufficient chemic...

AI Technical Summary

Problems solved by technology

[0009] (2) There is a large amount of elution in hydrochloric acid, etc. used to etch metal electrodes or transparent conductive films (ITO, etc.), and in the display manufacturing process, the eluted matter will recrystallize, etc., so there are difficulties in display manufacturing

[0013] About B 2 o 3 , disclosed in Japanese Patent Laid-Open No. 1-160844 containing B 2 o 3 20-23 cationic % glass, but B 2 o 3 The quantity is too much, the strain point is not high enough

In Japanese Patent Application Laid-Open No. 61-281041, it is disclosed that B 2 o 3 0.1 to 4% by weight of glass disclosed in Japanese Patent Laid-Open No. 4-175242 containing B 2 o 3 0.1 to 5 mol% of glass, disclosed in Japanese Patent Laid-Open No. 4-325435 containing B 2 o 3 0-3% by weight of glass, but B 2 o 3 The amount is small, and the durability against BHF is insufficient

[0014] Regarding BaO, Japanese Patent Application No. 4-325434 discloses glass containing 10-20% by weight of BaO, Japanese Patent Application No. 63-74935 discloses glass containing BaO 10-22% by weight, and Japanese Patent Application No. 59 -169953 discloses glass containing 15 to 40% by weight of BaO, but the amount of BaO is large, the coefficient of thermal expansion is large, and the density is also high

[0015] Regarding MgO, in JP-A 61-132536, a glass containing 6.5-12% by weight of MgO is disclosed; in JP-A-59-116147, a glass containing 5-15% by weight of MgO is disclosed; 60-71540 discloses a glass containing 5 to 17% by weight of MgO, and JP 60-42246 discloses a glass containing 10 to 25 mol% of MgO. However, glass with a large MgO content is prone to phase separation.

[0016] Regarding CaO, Japanese Patent Laying-Open 63-176332 discloses glass containing 11 to 25% by weight of CaO, Japanese Patent Laying-Open 58-32038 discloses glass containing 7 to 20 mol % of CaO, and Japanese Patent Laying-Open Hei 2 -133334 discloses a glass containing 8 to 15% by weight of CaO, JP 3-174336 discloses a glass containing 7 to 12% by weight of CaO, and JP 6-40739 discloses a glass containing 10 to 12% of CaO % by weight of glass, Japanese Patent Laid-Open No. 5-201744 discloses glass containing more than 18 cationic % of CaO, but if a large amount of CaO is contained, the coefficient of thermal expansion tends to increase

[0017] About Al 2 o 3 , disclosed in Japanese Patent Laid-Open No. 61-236631 containing Al 2 o 3 22.5-35 wt% glass, but Al 2 o 3 The amount is large, so the dissolution in chemicals such as hydrochloric acid is large

[0018] About P 2 o 5 , disclosed in JP-A 61-261232 and JP-A 63-11543 containing P 2 o 5 glass, but it deteriorates the semiconducting properties of the film, so it is not preferred

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