Patent ID: 7116612

Claim:
An optical pickup device driven by an error signal comprising: a grating element for receiving a light beam to create zero order diffracted light, ±first order diffracted light and ±second order diffracted light when the light beam passes through the grating element; an optical system for focusing the zero order, ±first order and ±second order diffracted light on a recording surface of an optical recording medium so as to form a spot of the zero order diffracted light on a first track extending on the recording surface, spots of the ±second order diffracted light on tracks adjacent to the first track, and spots of the ±first order diffracted light between the spot of the zero order diffracted light and the spots of the ±second order diffracted light; and an optical detector having first to fifth independent light-receiving elements, the first light-receiving element being adapted to receive returning light from the spot of the zero order diffracted light, the second and third light-receiving elements being adapted to receive returning light from the spots of the ±first order diffracted light, and the fourth and fifth light-receiving elements being adapted to receive returning light from the spots of the ±second order diffracted light, to produce output signals used to create an error signal.