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:
May. 19, 1992
Filed:
Jan. 06, 1989
Ricoh Company, Ltd., Tokyo, JP;
Abstract
An optomagnetic information recording and reproducing apparatus includes an optomagnetic optical pick-up for recording or reproducing information on or from an optomagnetic information recording disc. An optomagnetic optical pick-up includes a first diffraction grating for receiving light reflected from the disc and separating the light into a first transmitting light which transmits through the first diffraction grating beam and a first diffracted light beam which is diffracted by the first diffraction grating. A second diffraction grating is disposed to receive the first transmitting and diffracted light beams and discharges a second transmitting light beam and a second diffracted light beam. A tracking error detector is provided to receive the second transmitting light beam and a focusing error detector is disposed to receive the second diffracted light beam. An optomagnetic signal is obtained as a difference between outputs from the tracking and focusing error detectors.