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:
Nov. 12, 1985
Filed:
Mar. 07, 1983
Thomson-CSF, Paris, FR;
Abstract
A mobile pre-etched data carrier is provided in which the pre-etching is formed by a succession of discrete non continuous elements materializing the mean axis of the tracks. The spatial distribution of these discrete elements may be uniform or not. In a first embodiment, each discrete element is formed by a smooth track section. In a second embodiment, each discrete element comprises several sections defining a particular code. In other preferred variations of the invention, each element comprises, besides a portion centered on the mean axis of the tracks, one or more portions offset with respect to the axis. Finally, each of the pre-etchings may itself be preceded by an additional pre-etching element used for the purpose of synchronization. The tracking device comprises photodetector means, measuring circuits comprising sampler-inhibitors or storage integrator circuits and sampling circuits. A radial tracking error is formed from the evolution of the signals detected during successive passages.