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.

Date of Patent:
Jul. 30, 2013

Filed:

Mar. 05, 2012
Applicants:

Jiro Yoshinari, Tokyo, JP;

Naoki Hayashida, Tokyo, JP;

Shohei Fujii, Tokyo, JP;

Kazushi Tanaka, Tokyo, JP;

Inventors:

Jiro Yoshinari, Tokyo, JP;

Naoki Hayashida, Tokyo, JP;

Shohei Fujii, Tokyo, JP;

Kazushi Tanaka, Tokyo, JP;

Assignee:

TDK Corporation, Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03H 1/00 (2006.01); G03H 1/26 (2006.01);
U.S. Cl.
CPC ...
Abstract

An optimal recording exposure is determined by varying in the first to nth stages the recording exposure with a write laser beam to record a bright pattern image and a dark pattern image in each stage as the first to nth bright pattern images and the first to nth dark pattern images, respectively; irradiating the respective pattern images with a read beam to detect the intensity of a diffracted beam from the central portion of each image of the bright and dark patterns; calculating Sa/Sb=SNR, . . . , and Sa/Sb=SNR, where Sato Saare the intensity of a diffracted beam from the first to nth bright pattern images and Sbto Sb, are the intensity of s diffracted beam from the first to nth dark pattern images; and determining a recording exposure which is given at the SNRbeing the maximum value of the resulting SNRto SNR.


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