| 摘要 |
PROBLEM TO BE SOLVED: To provide an objective lens that suppresses degradation of an optical characteristic of an objective lens due to a temperature change, and to provide an optical pickup device that uses the objective lens.SOLUTION: An objective lens R comprises: lens surfaces R1 and R2 that converge BD light, DVD light and CD light to a spot shape at a prescribed numerical aperture; and an anti-reflection film R1a that is formed on the lens surface R1. The lens surface R1 is configured to include a BD exclusive area A1, and in a two-wavelength common area A2, a three-wavelength common area A3, and the BD exclusive area A1, the two-wavelength common area A2 and the three-wavelength common area A3, diffraction structures P1, P2 and P3 are formed, respectively. The anti-reflection film R1a is designed so that within a range of the two-wavelength common area A2, transmittance with respect to the BD light is maximum. |
