| 摘要 |
1,138,997. Magneto-optical recording &c. apparatus. INTERNATIONAL BUSINESS MACHINES CORP. 10 March, 1967 [8 April, 1966], No. 11272/67. Heading G5R. A magnetic data storage medium comprises a glass substrate 2 bearing a transparent magnetizable film 6 having a high Verdet constant such as europous chalcogenides or garnets so that information stored in film 6 as magnetized areas can be detected by the rotation of the plane of polarized light passing through the film. A thin dielectric layer 8, e.g. silicon monoxide, is formed on the film 6. A dichroic mirror 4 is provided between the glass substrate 2 and the film 6. A conventional magnetic write head 1 records bits of information as localized fields M in film 6. The record may be played back by the Faraday effect, a laser source or any other form of polarized light 10 being directed at a moving film 6 and analysed, after traversing film 6 and repeated reflection from surfaces 4, 8 by an analyser 14 which transmits light having a predetermined plane of polarization. A photo-cell 16 senses this transmitted light and a recording instrument 18 indicates its presence. |
