Optical pick-up for use with an opto-magnetic signal

U.S. Patent Number: 5278817

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 transmitging 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.

Inventors: Maeda; Hideo (Tokyo, JP), Ohuchida; Shigeru (Zama, JP), Kitabayashi; Junichi (Kawasaki, JP)

Assignee: Ricoh Company, Ltd. (Tokyo, JP)

Application Number: 07/833,012

Issued: 1994-01-11

Expired: 2006-01-11

Classes: 369/112.12 ; 369/112.14; 369/112.15; 369/44.14

Field of search: 369/44.11,44.14,44.12,112,109,111,44.37,44.38,103 359/15,569,558

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