| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a diffraction element, by which even after the direction of the diffraction element is controlled so as to correctly guide the reflected light from a disk by the diffraction pattern to a detecting part, the angle between the optical axis of a 1/4 wavelength plate included in the diffraction element an the polarization plane of the light from a laser light source is stably approximately 45 deg.. SOLUTION: The diffraction element 3 consists of a 1/4 wavelength plate 6, an upper transparent substrate 11a and a lower transparent substrate 11b stacked to interpose the 1/4 wavelength plate, and a UV-curing polymer member 13a as a diffraction pattern forming plate which has a diffraction pattern on its surface and which is staked on the upper side of the upper transparent substrate 11a. The angle between the optical axis of the diffraction pattern possessed by the diffraction pattern forming plate and the optical axis of the 1/4 wavelength plate 6 is approximately 45 deg.. |
