METHOD AND APPARATUS FOR MEASUREMENT OF FILM THICKNESS AS WELL AS METHOD AND APPARATUS FOR FORMATION OF MAGNETIC RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a film-thickness measuring apparatus by which the film thickness of two layers on the whole face and in the whole length of a magnetic recording medium can be measured and by which the film thickness during a coating process can be measured in real time. SOLUTION: The film-thickness measuring apparatus comprises a light emitting part 60 as a light source by which first polarized light and second polarized light having different polarization directions can be output toward the magnetic recording medium, a light receiving part 65 which detects quantities of light of the first polarized light and the second polarized light transmitted through the recording medium, and a controller 80 as a film-thickness calculation means which calculates the film thickness of a first layer and that of a second layer on the basis of a quantity of light to be output from the part 60 and on the basis of the quantities of light received by the part 65.