| 摘要 |
An object lens of an optical pickup apparatus, an object lens unit for the same, and an optical pickup apparatus using the object lens unit are provided to implement a compact optical pickup apparatus by using a single object lens, and optimize thickness on an axis of a lens and a focal distance of the lens. An object lens(OL) of an optical pickup apparatus records and reproduces information by concentrating a beam with wavelength lambda1 emitted from a light source on an information recording surface(RL). The wavelength lambda1 is larger than 380nm and smaller than 420nm. The object lens is a single lens which has at least one non-spherical surface. The object lens satisfies following formulas: 2.0<=Phi<=4.0, 1.5<n<1.8, 0.7<d/f<1.2, 0.8<NA<0.9, -1.17+2.8<d/f<-0.59n+2.0, wherein the Phi is a valid diameter of the light source, the d is thickness on an optical axis, the f is a focal distance, the n is a refraction index in the wavelength lambda1, a unit of the Phi is nm, a unit of the d is nm and a unit of the f is nm.
|
