Optical pickup device, optical information recording and reproducing apparatus and objective lens

An objective lens for use in an optical pickup device, comprising:

• at least two plastic lenses of a first plastic lens having positive refractive power and a second plastic lens having positive refractive power, wherein the first plastic lens and the second plastic lens are arranged in this order from the light source side;
• wherein the following expression (2-1) is satisfied:
• 0.6<d1/f<1.2 (2-1)
• where f (mm) represents a focal length of the objective lens for the light flux having wavelength λ, and d1 (mm) represents a distance between a light source-side optical surface of the first plastic lens and an optical information recording medium-side optical surface the first plastic lens on the optical axis.

An objective lens for use in an optical pickup device, comprising:

• at least two plastic lenses of a first plastic lens having positive refractive power and a second plastic lens having positive refractive power, wherein the first plastic lens and the second plastic lens are arranged in this order from the light source side;
• wherein the following expression (2-2) is satisfied:
• 2.2<f1·(1−β1)/(f2·(1−β2))<4.2 (2-2)
• where f1 (mm) represents a focal length of the first plastic lens for the light flux having wavelength λ, β1 represents a magnification of the first plastic lens, f2 (mm) represents a focal length of the second plastic lens for the light flux having wavelength λ and β2 represents a magnification of the second plastic lens.