Patent 7795165 was granted and assigned to E.I. Du Pont De Nemours And Company on September, 2010 by the United States Patent and Trademark Office.
An object of the present invention is to provide a lead-free bismuth glass wherein decrease of the degree of accuracy of the patterning is prevented. Specifically, the present invention provides a lead-free bismuth glass characterized in that said lead-free bismuth glass is used for an optical patterning glass material which is patterned by light irradiation and the optical-absorption coefficient to light with a wavelength of 365 nm is 300 to 3000 cm−1.