| 摘要 |
PROBLEM TO BE SOLVED: To provide a measuring method of a double refraction characteristic capable of measuring the double refraction characteristic of a protection layer of an optical recording medium in the classified state into in-plane double refraction and vertical double refraction. SOLUTION: When a measuring object disk 6 is irradiated with light from a semiconductor laser 1, four kinds of optical systems, namely, a polarization optical system including an objective lens 5 having a high numerical aperture, a polarization optical system including an objective lens 5 having a low numerical aperture, a non-polarization optical system including an objective lens 5 having a high numerical aperture, and a non-polarization optical system including an objective lens 5 having a low numerical aperture, are switched and used, and the in-plane double refraction characteristic and the vertical double refraction characteristic of the measuring object disk 6 are determined separately based on a received light quantity of reflected light by the measuring object disk 6, measured by a photodetector 9. COPYRIGHT: (C)2007,JPO&INPIT
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