Optical scanning device using a plurality of scanning spots

A device for simultaneously optically scanning a plurality of the information tracks in an information plane of an optical record carrier, said device comprising:

• a radiation source for supplying a series of scanning beams;
• an objective system for focusing the scanning beams to form a corresponding series of scanning spots focussed on the information plane, each positioned on a respective information track to scan such track;
• a series of photodetectors for respectively receiving radiation produced from the respective tracks by the scanning spots and converting such radiation into corresponding respective detection signals;
• a plurality of error signal generating circuits respectively coupled to respective ones of said photodetectors for deriving respective error signals from the detection signals produced by the respective photodetectors, each error signal being either (i) a focus error signal indicative of focus error of the associated scanning spot with respect to the track being scanned thereby, or (ii) a tracking error signal indicative of tracking error of the associated scanning spot with respect to the track being scanned thereby;
• the respective error signals relating to respective ones of said tracks;
• and
• signal combining means coupled to at least two of the error signal generating circuits for combining the error signals produced thereby so as to derive a control signal for control of at least one of (1) focus of each of the scanning beams, (2) tracking of each of the scanning beams, and (3) tilt of the record carrier relative to the scanning beams.