发明名称 MANUFACTURE OF PHOTOMAGNETIC DISC
摘要 PURPOSE:To uniform distribution of coercive force of an photomagnetic disc by forming a diffusion layer having a film thickness corresponding to the distribution of coercive force of a magnetic layer onto the magnetic layer so as to apply proper amount of oxygen to the magnetic layer through the diffusion layer. CONSTITUTION:The magnetic layer 15 is formed on the base by sputtering while the base 16 is turned so as to measure the distribution of coercive force of the magnetic layer 15 in radial direction. A correcting plate 12 is used and the film thickness of a part having a large coercive force is formed thinly on the magnetic layer 15 while turning the base 16 so as to form the diffusion layer 14 having the film thickness corrresponding to the distribution of coercive force. In leaving a disc 11 in an oxygen atmosphere, the oxygen transmits through the diffusion layer 14 so as to cause demagnetization of the rare-earth metal in the magnetic layer 15. The distribution of coercive force is measured repetitively and after the coercive force is arranged uniformly, the reflecting layer is formed on the diffusion layer by using the correcting plate so that the sum of the film thickness of the diffusion layer and the film thickness of the reflecting layer is made constant. Since the same type of material is used for the diffusion layer as that of the reflecting layer, the diffusion layer acts like the reflecting layer.
申请公布号 JPS60103538(A) 申请公布日期 1985.06.07
申请号 JP19830210155 申请日期 1983.11.09
申请人 MATSUSHITA DENKI SANGYO KK 发明人 UCHIDA KIYOSHI
分类号 G11B11/10;G11B11/105 主分类号 G11B11/10
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