Abstract: An optical scanning device for scanning an information plane (2) having tracks is described, which device comprises a radiation source (4) supplying a scanning beam (3) and an objective system (5) for focusing the scanning beam to a scanning spot on the information plane (2). To obtain two tracking spots, two grating parts located at both sides of the scanning beam and capturing border rays from the radiation source are used.

Abstract: A reading apparatus including a plurality of photodiodes each provided with a storage capacitor, the photodiodes adapted to store electric charge in the storage capacitor upon receiving light, a plurality of analog switches each connected in series with one end of each of the photodiodes, an element for leading out an amount of electric charge as a signal when the amount of electric charge is stored in the storage capacitor, a shift register for rendering the plurality of analog switches conductive successively in time sequence, wherein capacitance of the storage capacitor is larger than parasitic capacitance of the analog switch.