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. 07, 1981
Filed:
Feb. 17, 1978
Applicant:
Inventors:
David E Birt, Hanwell, GB;
Lyn Holt, Maidenhead, GB;
Assignee:
E M I Limited, Hayes, GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 84 ; 264107 ; 369272 ;
Abstract
A record having an information track cut into the surface and a visible pattern formed on surface 'lands' bordering the track. The pattern is shallower than the track depth, typically 0.7 micron for a 25 micron sound microgroove record track. A method of providing the marking by applying solvent to a lacquer before cutting a master is described.