Patent ID: 8869558

Claim:
A process for producing a glass substrate, comprising: chemically tempering a glass substrate in a molten salt comprising at least KNO 3 to provide a chemically tempered glass substrate, cleaning the chemically tempered glass substrate to provide a cleaned glass substrate, forming a silver film on the surface of the cleaned glass substrate to provide a glass substrate having a silver film formed thereon, subjecting the glass substrate having the silver film formed thereon to heat treatment to diffuse silver ions from the glass substrate surface to the inside, and after said heat treatment washing and removing silver remaining on the glass substrate surface which was not diffused in the inside of the glass substrate, wherein the glass substrate produced has a silver amount of from 0.2 to 100 μg/cm 2 at a depth of 40 μm from the glass substrate surface, and wherein the glass substrate produced comprises a surface compressive stress layer, and has a ratio (T1/T2) of the transmittance T1 at a wavelength of 428 nm to the transmittance T2 at a wavelength of 650 nm of at least 0.95, and a transmittance at a wavelength of 428 nm of at least 86% when the thickness of the glass substrate is from 0.1 to 3.0 mm.