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. 03, 1979
Filed:
May. 27, 1977
U.S. Philips Corporation, New York, NY (US);
Abstract
Apparatus for reading a record carrier provided with a spiral structure in which sound and/or image information is stored in the form of frequency modulated or phase modulated signals is disclosed. The carrier structure is composed of coplanar regions of variable length separated by coplanar areas of variable length. Where the regions and areas are all in the same plane the regions and areas have different coefficients of reflection or transmission. Where the regions and areas are not coplanar they are spaced by a distance sufficient to produce in response to impinging radiation a one-half wave length difference in the radiation exiting the regions and areas. The apparatus provides a light beam with a frequency that facilitates diffraction of the beam by the areas and regions, and also provides a radiation sensitive detection system for converting the light beam modulations caused by the record carrier into a corresponding electrical signal.