OBJECTIVE FOR OPTICAL RECORDING MEDIUM AND OPTICAL PICKUP DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain an objective for an optical recording medium coping with short wavelength light and having a large NA which can make aberration such as chromatic aberration good even by the wavelength fluctuation associated with the mode hop phenomenon of a laser diode by constituting the objective of two lenses and making the two lenses have at least one diffraction optical surface and one aspherical surface, and an optical pickup device. SOLUTION: In this objective for the optical recording medium constituted of two lenses L1 and L2 having positive refractive power, the two lenses L1 and L2 have at least one diffraction optical element surface (DOE surface) and at least one aspherical surface, and the objective is set so that NA is >=0.7 as a whole.