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:
Oct. 03, 1989
Filed:
Apr. 08, 1988
Applicant:
Inventors:
Hiromi Seo, Odawara, JP;
Osami Kushizaki, Hiratsuka, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 44 ; 369 46 ;
Abstract
The peak value of upper envelope of an optical disk read signal is detected, and a signal indicative of the detected peak value or upper envelope is used to correct the total reflected light amount signal. That is to say, two output signals delivered from a pair of horizontally symmetrical photo detectors, which detect the reflected light of a light spot, added together, and furthermore a signal indicative of the result of this addition is added to the signal indicative of the peak value or upper envelope to produce a total reflected light amount signal which is not influenced by the pits on the optical disk.