Patent ID: 8199623

Claim:
An optical pickup comprising: a semiconductor laser configured to emit a light beam; a beam splitter arranged relative to the semiconductor laser to split the light beam emitted by the semiconductor laser into transmitted light and reflected light; a collimating lens arranged to parallelize the reflected light from the beam splitter; an objective lens arranged to converge the reflected light being parallelized by the collimating lens on an optical disk; an aperture arranged to limit the reflected light incident on the objective lens; and a front monitor arranged to receive the transmitted light and detect luminous energy of the transmitted light to detect luminous energy of the reflected light emitted from the objective lens, with the front monitor being disposed near an optical axis of the transmitted light so that the following is satisfied: 1≦( S×L )/( s×f )≦6.8 where S is a total area of an entrance pupil of the objective lens, f is an optical distance from an emission portion of the semiconductor laser to the collimating lens, s is a total effective receiving area of the front monitor, and L is an optical distance from the emission portion of the semiconductor laser to the front monitor, the front monitor including a receiver that is arranged to receive the transmitted light, the total effective receiving area of the front monitor corresponding to a total area of the receiver, and the optical distance from the emission portion of the semiconductor laser to the front monitor corresponding to a distance from the emission portion of the semiconductor laser to the receiver.