| 摘要 |
PROBLEM TO BE SOLVED: To provide a high NA objective lens, wherein a lens is constituted of three lens groups, and the curvature of the lens surface is mitigated by dispersing the power of the lens surface with reference to a high NA luminous flux, the eccentricity allowance between the lens groups, a viewing angle allowance and an operating distance are satisfactorily secured and to provide an optical pickup device and a recording/ reproducing device. SOLUTION: The objective lens is used for recording/reproducing optical information on/from an optical information recording medium, and the lens is constituted of three groups of a first lens group, a second lens group and a third lens group arranged in order from a light source side, and the numerical aperture NA on the optical information recording medium side satisfies 0.60<NA<0.99. Besides, the lens is constituted of three groups of the first lens group having a positive refractive power, the second lens group having a positive refractive power and the third lens group having a positive refractive power. Alternatively, the lens is constituted of three groups of the first lens group having a negative refractive power, the second lens group having the positive refractive power and the third lens group having the positive refractive power. |
