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US 6,634,186 B2Granted
Process for cutting a glass sheet and a glass disk for a recording medium
AssigneeNippon Sheet Glass Co., Ltd.
InventorKoichi Abe
Life of this patent
Estimating the term…
Abstract
A U-shaped groove is formed in a glass sheet along a cutting line and the sheet is cut by breaking along the groove. The groove is formed by heating a sheet portion including the cutting line by a laser beam, cooling it to lower its density, and etching that portion to dissolve it. Every surface exposed by cutting the sheet has a pair of edges which are properly beveled and rounded.
Claims15
A process for cutting a glass sheet, comprising the steps of:
- heat treating a glass sheet to be cut by first applying at least one laser beam onto a surface of the glass sheet and scanning the laser beam along a cutting line along which the glass sheet is to be cut, so that a sheet portion including said cutting line may be heated to a temperature equal to, or above a glass transition point of the glass sheet, and then cooling the sheet portion to thereby cause the sheet portion to protrude from the remaining portion of the glass sheet, protruding sheet portion having a larger specific volume and a lower density than the remaining portion of the glass sheet;
- etching the heat-treated sheet to form a groove in and along the sheet portion including said cutting line;
- and
- breaking the glass sheet along said groove.
1 more element
Dependencies are inferred from the claim text.