Patent ID: 7339877

Claim:
An optical head device comprising: a light emission source configured to emit a plurality of laser beams with different wavelengths; a light receiving device configured to detect a signal in said beams with said wavelengths; and an optical system including an objective lens and collimator, said optical system being used in common for first and second optical recording media of different kinds, said optical system configured to transmit the laser beams emitted by the light emission source and detected by the light receiving device, wherein the RIM intensity pertaining to said optical system is not less than 0.1, a first divergence angle (full angle at half maximum) of a first laser beam in the plurality of laser beams to the first optical recording medium at a time of recording or reproducing information is not less than 7.5 degrees, a second divergence angle (full angle at half maximum) of a second laser beam in the plurality of laser beams to the second optical recording medium at a time of recording or reproducing information is in the range of 5 to 8 degrees, the magnification of said optical system is in the range of 4 to 6, and a light emission part of the first laser beam and a light emission part of the second laser beam are arranged with an interval of about 30 to 500 μm.