Optical head with semiconductor laser

Claim 1

An optical head comprising: a semiconductor substrate having a surface; a semiconductor laser arranged on said surface of the semiconductor substrate for emitting a laser beam; a light receiving means including a plurality of photodetectors formed in said surface of the semiconductor substrate; a collimator lens for converting said laser beam emitted by said semiconductor laser into a substantially parallel laser beam; an objective lens for converging said substantially parallel laser beam onto a magneto-optical record medium; a beam dividing means arranged between said collimator lens and said objective lens for dividing a laser beam reflected by said magneto-optical record medium into first and second return beams; and a polarization beam splitting means arranged between said semiconductor laser and said collimator lens such that an integral unit is formed together with said semiconductor substrate, and including gratings for diving the laser beam emitted by said semiconductor laser into a main beam which is used to write or read information on or from said magneto-optical record medium and sub-beams which are used to derive a tracking error signal, a first hologram pattern for diffracting said first return beam, a second hologram pattern for diffracting said second return beam, and a polarization beam splitting plane arranged substantially in parallel with an optical axis of a zero order beam emanating from said second hologram pattern for splitting +1-order and/or -1-order diffracted beam emanating from said second hologram pattern in accordance with a polarizing direction of the beam; whereby +1-order and -1-order diffracted beams emanating from said first hologram pattern and beams emanating from said polarization beam splitting plane are separately received by said plurality of photodetectors of said light receiving means.