OPTICAL ELEMENT FOR CORRECTION OF CHROMATIC ABERRATION, OPTICAL PICK-UP DEVICE HAVING OPTICAL ELEMENT FOR CORRECTION OF CHROMATIC ABERRATION, OPTICAL REPRODUCING DEVICE HAVING OPTICAL PICK-UP DEVICE AND OPTICAL RECORDING AND REPRODUCING DEVICE

摘要

This invention provides an optical element for correcting a chromatic aberration corresponding to a short wavelength of a light source and further provides an optical pick-up device having the optical element for correcting a chromatic aberration and adapting for a further higher recording density and larger capacity of the optical recording medium, the optical reproducing device and the optical recording and reproducing device. The optical element for correcting a chromatic aberration arranged between a light source such as a semiconductor laser or the like with a wavelength being 440 nm or less and an objective with numerical aperture NA being 0.55 or more, a focal distance being 1.8 mm or more and an Abbe number at the d-line (587.6 nm) being 95.0 or less has a convex lens with at least an Abbe number at the d-line being 55 or more and a concave lens with an Abbe number at the d-line being 35 or less.