Patent ID: 7813251

Claim:
An optical head device, comprising: a first laser light source for emitting a first light beam of a first wavelength λ 1 (400 nm to 415 nm); a second laser light source for emitting a second light beam of a second wavelength λ 2 (650 nm to 680 nm); a focusing optical system for focusing the first and second light beams that are emitted from the first and second laser light sources respectively, and forming minute spots on information recording surfaces of first and second optical information media; and a photodetector for receiving the first and second light beams reflected respectively by the information recording surfaces of the first and second optical information media to output an electric signal in accordance with light amounts of the first and second light beams; wherein a spherical aberration correction element has a first convex lens and a second convex lens, the second convex lens being positioned nearer to the focusing optical system than the first convex lens, and the second convex lens is disposed in light paths of the first and second light beams, and spherical aberrations of the minute spots are controlled by moving the second convex lens along the light paths of the first and second light beams.