Manufacturing method of glass substrate

Abstract

The invention provides a making method of a glass substrate, can reproduce designed temperature distribution in a high precision, and can improve flatness (warpage) and strain of the glass substrate. In the glass substrate making method based on overflow down-drawing method, in order to reduce the warpage and strain of the glass substrate, on one hand, a roller is employed to pull a thin glass flowing from a formation body towards a lower direction, and on the other hand, temperature distribution of the width direction of the thin glass formed in annealing is controlled to be under presetting. Furthermore, the roller is cooled so the straightness of the roller can be kept in a preset standard value, and the temperature of the roller is controlled so as to prevent generation of influence to the temperature distribution.

Description

technical field [0001] This invention relates to the manufacturing method of the glass substrate which manufactures a glass substrate. Background technique [0002] A thin glass plate with a thickness of, for example, 0.5 to 0.7 mm is used as a glass substrate used in a flat panel display (hereinafter referred to as “FPD”) such as a liquid crystal display or a plasma display. This glass substrate for FPD has a size of 300×400 mm in the first generation, for example, but becomes 2850×3050 mm in the tenth generation. [0003] In order to manufacture such a large-sized glass substrate for FPDs, an overflow down-draw method is often used. The overflow down-draw method includes: a process of forming thin plate glass (sheet glass) under the forming body by overflowing (overflowing) molten glass from the upper part of the forming body in a forming furnace; and annealing the thin plate glass in an annealing furnace cooling process. In the annealing furnace, the sheet glass is dra...

AI Technical Summary

Problems solved by technology

However, in the annealing process, if the front end of the roller shaft 21 of the roller 20 that conveys the sheet glass is excessively cooled as described above, since the front end surface of the roller shaft 21 is not particularly insulated from the inside of the furnace, the front end surface of the roller shaft 21 is not insulated from the inside of the furnace. The thin plate glass near the front end of 21 is excessively cooled, or, even if the front end surface of the roller shaft 21 has a certain degree of thermal insulation performance, the low temperature roller shaft will take away more than 100% of the glass that passes through the roller material and contacts the surface of the roller. necessary heat, therefore, the equilibrium of the above-mentioned temperature distribution is disrupted, making it impossible to reproduce the pre-designed temperature distribution

As a result, the warpage and strain of the manufactured glass substrate tend to increase

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