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:
Jan. 11, 1983
Filed:
Mar. 30, 1981
Harald Ahrens, Hanover, DE;
Dieter Schulz, Hanover, DE;
Polygram GmbH, , DE;
Abstract
A centering device for the manufacture of a center hole in disks, particularly metallized video disks with spiral information tracks and an information-free center, employs a measuring head for the emission of a light beam onto the disk surface. The light beam is precisely situated at a boundary between the information portion and the information-free portion of the disk during a full disk revolution (a transition criterion) and that said criterion is evaluated for the identification of the center. An electronic control circuit is provided for the control of the displacements required for the measuring head and of the disk centered in planes which are parallel relative to one another.