Patent ID: 7415841
Filing Date: 2008-08-26
Classification: C03C,G11B

Abstract:
1. A method for producing a glass substrate for information recording medium, the method comprising the steps of: (a) processing a plate-like glass substrate in a doughnut shape; (b) grinding the doughnut-shaped glass substrate to smoothen a surface thereof; (c) oxidizing metal-containing particles adhered to a surface of the glass substrate by heating in an oxidation atmosphere; (d) adding an oxidizing agent to a potassium-containing chemical strengthening treating solution and heating the potassium-containing chemical strengthening treating solution including the oxidizing agent; (e) oxidizing iron particles in the potassium-containing chemical strengthening treating solution by pre-heating the chemical strengthening treating solution before immersing the glass substrate in the chemical strengthening treating solution; and (f) contacting the glass substrate with the potassium-containing chemical strengthening treating solution.