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. 08, 2005
Filed:
Jan. 16, 2003
Kouji Takahashi, Tokyo, JP;
Takemi Miyamoto, Tokyo, JP;
Hiroshi Tomiyasu, Tokyo, JP;
Genshichi Hata, Tokyo, JP;
Tomotaka Yokoyama, Tokyo, JP;
Kouji Takahashi, Tokyo, JP;
Takemi Miyamoto, Tokyo, JP;
Hiroshi Tomiyasu, Tokyo, JP;
Genshichi Hata, Tokyo, JP;
Tomotaka Yokoyama, Tokyo, JP;
Hoya Corporation, Tokyo, JP;
Abstract
A substrate for an information recording medium has a microwaviness average height Ra' not greater than 0.05 microinch as measured by a contactless laser interference technique for measurement points within a measurement region of 50 μm□-4 mm□ on a surface of the substrate. The microwaviness average height Ra′ is given by:where xi represents a measurement point value of each measurement point, {overscore (x)} representing an average value of the measurement point values, n representing the number of said measurement points. Alternatively, the substrate has a waviness period between 300 μm and 5 mm and a waviness average height Wa of 1.0 nm or less as measured by the contactless laser interference technique for measurement points in a measurement region surrounded by two concentric circles which is spaced from a center of a surface of the substrate by a predetermined distance. The waviness average height Wa is given by:where Xi represents a measurement point value of each measurement point, {overscore (X)} representing an average value of the measurement point values, n representing the number of said measurement points.