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:
Jun. 16, 1987
Filed:
Aug. 08, 1985
Osamu Tajima, Ibaraki, JP;
Shigehiro Ito, Toride, JP;
Victor Company of Japan, Ltd., Yokohama, JP;
Abstract
An optical type disc is recorded with information signals on each sloping surface of a spiral or concentric V-shaped grooves formed on a recording surface thereof, wherein the information signals are recorded as rows of geometrical depressions or projections on each sloping surface of the V-shaped groove and the inclination angle of the bottom surface of the depression or the top surface of the projection is greater than the inclination angle of the sloping surface of the V-shaped groove. An optical type reproducing apparatus reproduces the signals from the disc by relatively scanning the sloping surface of the V-shaped groove by a reproducing spot having a diameter smaller than the width of the V-shaped groove. The reproducing apparatus comprises tracking spot forming system for forming a tracking spot across two mutually adjacent sloping surfaces of the V-shaped grooves at a position deviated with respect to the reproducing spot in a width direction of the V-shaped groove by a distance of 1/4 the width of the V-shaped groove, a photoelectric transducer for independently receiving light reflected from the two mutually adjacent sloping surfaces of the V-shaped grooves, and a moving mechanism for moving an optical system in the width direction of the V-shaped groove responsive to an output of the photoelectric transducer so that the reproducing spot is formed along a predetermined sloping surface of the V-shaped groove.