OPTICAL PICKUP DEVICE

摘要

In a conventional optical pickup device using a two-wavelength semiconductor laser, an optical beam from an inferior optical information recording medium transmits a 1/4 wavelength plate and becomes a p-polarized light instead of an s-polarized light. Accordingly, it is impossible to control a focus tracking error signal. Provided is an optical pickup device including: a first semiconductor laser (103) for emitting an optical beam (102) having a first wavelength corresponding to recording/reproduction to/from a first optical information recording medium (101); a second semiconductor laser (106) for emitting an optical beam (105) having a second wavelength longer than the first semiconductor laser corresponding to a second optical information recording medium (104); a diffraction grating (107) for diffracting an optical beam of the first and the second wavelength into 0 degree diffracted light and plus and minus 1 degree diffracted light; a wavelength plate (108); a polarization hologram element (109) for diffracting a reflected light from the first and the second optical information recording medium; a collimator lens (114); an objective lens (115); and a first light receiving element group (110) to a third light receiving element group (112) for receiving diffracted light from a hologram element.