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:
Feb. 24, 2015
Filed:
Jan. 29, 2013
Hoya Corporation, Tokyo, JP;
Tatsuya Sasaki, Tokyo, JP;
Takahiro Miyazaki, Tokyo, JP;
Hoya Corporation, Tokyo, JP;
Abstract
In a mask blank substrate having two main surfaces and four end faces, a central point is set on the main surface, a first axis of symmetry that passes through the central point and that is parallel to one of the end faces and a second axis of symmetry that passes through the central point and that is perpendicular to the first axis are respectively set, measurement points are set in the form of a grid with respect to the first and the second axes so as to measure heights of the main surface from a reference plane at the measurement points, respectively, differences each between measured height values at those measurement points located at positions axisymmetric with respect to the first axis are calculated. Those differences corresponding to at least 95% of the total number of the calculated differences between the measured height values are within a predetermined value.