| 摘要 |
PURPOSE:To make measurement of variation of optical characteristics during manufacture so as to obtain a recording medium having the optimum readout efficiency, by monitoring the reflectivity or Kerr hysteresis of a sample through a received laser beam with a photodetector. CONSTITUTION:A laser beam from a light source is introduced to a vacuum tank 1 through a mirror 2, polarizing plate 3, and window 4 and made incident to a sample 7 through mirrors 5 and 6. An electromagnet 8 which impresses a magnetic field upon the sample 7 in the vertical direction is provided above the sample 7 and the magnetic field is swept at a prescribed value when the Kerr hysteresis is measured. An amorphous film is supplied to the sample 7 from two ingots prepared in electron beam evaporators 9 and 10 and each ingot is separated from each other by a plate 11 and each evaporating material is measured by sensors 12 and 13. Reflected lights from the sample 7 are splitted by a mirror 18 after passing through mirrors 14 and 15 and window 16 and supplied to photodetectors 21 and 22 through analyzers 19 and 20. Each output of the photodetectors 21 and 22 is supplied to a monitor device through a differential amplifier 23 and the light quantity and change in light quantity resulting from the rotation of the plane of polarization are measured. |
