Nippon Electric Glass Co., Ltd.

Hisatoshi Aiba

Takahide Fujii

Tsuyoshi Okuno

Katsutoshi Fujiwara

Takahiro Kawaguchi

Yoshinari Kato

A method of manufacturing a glass sheet includes: an initial crack forming step of forming an initial crack on a mother glass sheet (MG); and a cleaving step of causing a crack (CR) to propagate in a direction along a preset cleaving line (CL) and in a thickness direction of the mother glass sheet (MG), the crack starting from the initial crack, through use of a thermal stress generated by heating of an irradiation region (SP) of laser light (L) and cooling of a cooling region (CP). The cleaving step includes heating a surface layer (SL) and an inner portion (IL) of the mother glass sheet (MG) with the laser light (L) in the irradiation region (SP) and setting a difference ΔT between a highest temperature in the irradiation region (SP) and a lowest temperature in the cooling region to 575° C. or more.

Glass plate and method for manufacturing glass plate

This method includes: an initial crack forming step of forming an initial crack (CR) on a first surface (MG) of a mother glass sheet (MG); and a laser irradiation step of irradiating the mother glass sheet (MG) with laser light (L) to cause a crack (CR) to propagate along a preset cleaving line (CL) through use of the initial crack (CR) as a starting point. The laser irradiation step includes irradiating a second surface (MG) of the mother glass sheet (MG) with the laser light (L) to heat a surface layer (SL) and an inner portion (IL) of the second surface (MG), to thereby cause, through a thermal shock caused by the heating, the crack (CR) to propagate in an entire thickness direction of the mother glass sheet (MG) while propagating along the preset cleaving line (CL).

Method for manufacturing glass sheet

This method includes a laser irradiation step of radiating, in at least a part of a preset cleaving line (CL) of a mother glass sheet (MG), laser light (L) to a position (OSP) separated from the preset cleaving line (CL) so that a crack (CR) propagates along the preset cleaving line (CL).

Glass plate manufacturing method

The present invention is aimed to provide a method for producing a glass substrate with a thickness of not more than 200 &#x3bc;m, which is satisfied with the quality required for a substrate on which a thin-film electric circuit is formed, and a sheet glass substrate obtained according to this method. The present invention is concerned with a method for producing a glass substrate having a sheet thickness of from 10 to 200 &#x3bc;m, including a forming step of forming a molten glass into a ribbon shape in accordance with a down draw method, an annealing step of annealing the glass ribbon, and a cutting step of cutting the glass ribbon to give a glass substrate, wherein an average cooling rate in a temperature range of from the (annealing point+200&#xb0; C.) to the (annealing point+50&#xb0; C.) is controlled to the range of from 300 to 2,500&#xb0; C./min.

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Shiga, Japan

Hisatoshi Aiba