The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 11, 2006
Filed:
Mar. 05, 2003
Hirokazu Takeuchi, Otsu, JP;
Nagaharu Nakajima, Otsu, JP;
Tadashi Seto, Otsu, JP;
Mitsutaka Nakae, Otsu, JP;
Hirokazu Takeuchi, Otsu, JP;
Nagaharu Nakajima, Otsu, JP;
Tadashi Seto, Otsu, JP;
Mitsutaka Nakae, Otsu, JP;
Nippon Electric Glass Co., Ltd., Shiga, JP;
Abstract
A prism is produced by the steps of feeding a glass base material into a heating furnace, the glass base material having surfaces to be prism surfaces after forming, the Ra value of the surface roughness of the surface being less than the Ra value corresponding to #170, the glass base material having a predetermined dimensional ratio, grasping the glass base material with feeding means, and feeding the glass base material into a heating furnace to heat the glass base material to a temperature so that a minimum viscosity of the glass base material becomes equal to or more than 10Pa·s and less than 10Pa·s, drawing and forming the lower portion of the glass base material, and then cutting the glass base material to obtain a longer body having a desired dimension and prism surfaces with the Ra value of the surface roughness equal to or less than a quarter of the wavelength of incident light, and cutting the longer body into desired length.