To provide an optical head device and an optical information recording and reproducing apparatus 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.
A light having a wavelength of 405 nm, emitted from optics 1a, is input to an objective lens 4a as a collimated light, and is focused on a disk 5a having a thickness of 0.1 mm. A light having a wavelength of 650 nm, emitted from optics 1b, is input to the objective lens 4a as a diverged light, and is focused on a disk 5b having a thickness of 0.6 mm. A light having a wavelength of 780 nm, emitted from optics 1c, is input to the objective lens 4a as a diverged light, and is focused on a disk 5c having a thickness of 1.2 mm. A spherical aberration, which remains for the light having a wavelength of 650 nm or 780 nm, is decreased by the change of the magnification of the objective lens 4a, further the decreased spherical aberration is decreased by using a wavelength selective filter 3a.
| JP2000187870A | 2000-07-04 | |||
| JP2001067700A | 2001-03-16 | |||
| JPH10334504A | 1998-12-18 |
| WO2002021520A1 | 2002-03-14 |
Akitaka Kimura
Toshio Asai