An optical head device and an optical recording and reproducing apparatus
using this optical head device, which can record information and
reproduce the recorded information at any of optical recording media,
such as a next generation optical recording medium, in which the
wavelength of the light source is made to be shorter, the numerical
aperture of the objective lens is made to be higher, and the thickness of
the recording medium is made to be thinner, and conventional recording
media of DVD and CD standards, are provided. A light having wavelength of
405 nm, emitted from one of optics, is inputted to an objective lens as a
collimated light, and is focused on a disk having thickness of 0.1 mm. A
light having wavelength of 650 nm, emitted from the other of optics, is
inputted to the objective lens as a diverged light, and is focused on a
disk having thickness of 0.6 nm. A spherical aberration, which remains
for the light having wavelength of 650 nm, is decreased by the change of
the magnification of the objective lens, further the decreased spherical
aberration is debased by using a wavelength selective filter.