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. 30, 2013
Filed:
Feb. 07, 2012
Masaaki Takata, Tokyo, JP;
Long Shao, Tokyo, JP;
Kei Iwata, Tokyo, JP;
Tomonori Ogawa, Tokyo, JP;
Asahi Glass Company, Limited, Tokyo, JP;
Abstract
The present invention provides a synthetic silica glass for an optical member in which not only a fast axis direction in an optical axis direction is controlled, and a birefringence in an off-axis direction is reduced, but a magnitude of a birefringence in the optical axis direction is controlled to an arbitrary value, such that an average value of a value BR cos2θdefined from a birefringence BR and a fast axis direction θas measured from a parallel direction to the principal optical axis direction is defined as an average birefringence AveBR cos2θ, and when a maximum value of a birefringence measured from a vertical direction to the principal optical axis direction of the optical member is defined as a maximum birefringence BRin an off-axis direction, the following expression (1-1) and expression (2-1) are established:−1.0≦AveBR cos2θ<0.0  (1-1)0.0≦BR≦1.0  (2-1).