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:
Feb. 07, 1989
Filed:
Jun. 12, 1986
Hirohisa Yamaguchi, Tokyo, JP;
Horoshi Usami, Tokyo, JP;
Tadao Nagai, Sagamiko, JP;
Akira Mashimo, Tokorozawa, JP;
TEAC Corporation, Tokyo, JP;
Abstract
A disc comprises a recording surface which is divided into a plurality of equiangular sectoral regions and a guide track formed on the recording surface. Each track turn of the guide track is constituted by a row of pits formed in every other equiangular sectoral regions, and the pit is only formed in one of two mutually adjacent track turns of the guide track in each equiangular sectoral region so that the pits are formed in every other track turns in a radial direction of the disc in each equiangular sectoral region. An apparatus for playing the disc comprises a circuit for producing a switching pulse signal having a period dependent on a period of the pits of the guide track based on signals which are reproduced from the two mutually adjacent track turns by sub light beams, a circuit for alternately inverting a polarity of signals which are reproduced from the two mutually adjacent track turns by a main light beam for every one half period of the switching pulse signal and for generating a tracking error signal, a tracking device, and a device for recording and reproducing an information signal on and from an intermediate part of the disc between the two mutually adjacent track turns.