Photomagnetic disc device

Abstract

Abstract PURPOSE:To execute erasing, recording and reproducing simultaneously by mutual connection of two optical systems by using two optical systems provided with bias magnetic field applying devices respectively and to be used for erasing and recording/reproducing laser light beams. CONSTITUTION:A bias magnetic field is applied to a magnetic disc 14 by an electromagnet 51. Light from a semiconductor laser 31 is condensed to a photomagnetic medium layer 2 through a colimating lens 32, a beam splitteer (BS)33, a lambda/4 plate 34 and an objective lens 35 and erased. The reflected light is reflected by the BS33 as a tracking and focusing control signal for the objective lens 35. Light from a semiconductor laser 37 is recorded on the surface of the photomagnetic medium layer 2 through a colimating lens 38, a filter 39, a polarizer 40, a BS41, and an objective lens 42. Light from a semiconductor laser 43 is condensed on the surface of the medium layer 2 through a colimating lens 44, a polarizer 40 and the objective lens 42 and the reflected light is reflected by the BS41, made incident to a photodetector through an analyzer 47 and then reproduced.

Inventors

• 👤 Akio Nimata
• 👤 彰男 二俣
• 👤 Shinji Okada
• 👤 真次 岡田
• 👤 Yasuyuki Ozawa
• 👤 靖之 小沢
• 👤 Toshitaka Iwamoto
• 👤 岩本　敏孝
• 👤 Koichi Ogawa
• 👤 小川　紘一

Bibliographic Details