Glass substrate for flat panel display

Abstract

A flat panel display glass substrate includes a glass comprising, in mol %, 55-80% SiO2, 3-20% Al2O3, 3-15% B2O3, and 3-25% RO (the total amount of MgO, CaO, SrO, and BaO). The contents in mol % of SiO2, Al2O3, and B2O3 satisfy a relationship (SiO2+Al2O3) / (B2O3)=7.5-17. The strain point of the glass is 665° C. or more. The devitrification temperature of the glass is 1250° 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° C. / min and at 550° 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}×106.

Description

[0001] This application is a Divisional of U.S. application Ser. No. 13 / 537,615, filed Jun. 29, 2012, which claims priority to Provisional U.S. Application No. 61 / 513,205 filed Jul. 29, 2011; which claims priority to Japanese Application No. 2011-147758, filed Jul. 1, 2011 and JP 2012-059132 filed Mar. 15, 2012, the disclosure of each is incorporated herein by reference.BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to glass substrates for flat panel displays and methods for manufacturing the glass substrates.

[0004] 2. Related Background Art

[0005] Flat panel displays with small thickness and low power consumption, such as a thin film transistor (TFT) liquid crystal display and an organic electroluminescence (EL) display, have in recent years been employed as displays for mobile devices and the like. These displays typically include a glass substrate.

[0006] There are the following types of TFTs: an amorphous silicon (α-Si) TFT; and a polysil...