Optical head for recording and reproducing information on and/or from optical record medium

Abstract

In an optical head for recording and reproducing information on and from an optical record medium such as optical disk and optical card including a semiconductor laser diode for emitting a laser beam having an elliptical cross sectional configuration, a collimator lens for converting the laser beam emitted from the laser diode into a parallel laser beam, a beam shaping prism for converting the laser beam emanating from the collimator lens into a laser beam having a circular cross sectional configuration, a transmissive diffraction grating for dividing the laser beam emanating from the beam shaping prism into a plurality of laser beams and an objective lens for projecting the laser beams emanating from the transmissive diffraction grating onto the optical record medium, in order to avoid the influence of a laser beam which is reflected by the transmissive diffraction grating and is made incident upon a laser emitting point of the laser diode, the transmissive diffraction grating is inclined with respect to an optical axis to such an extent that the laser beam reflected by the transmissive diffraction grating is not made incident upon the laser emitting point. Then, the semiconductor laser diode can generate the laser beam stably, and thus the recording and reproducing can be performed accurately.

Dependencies are inferred from the claim text.