| 摘要 |
A scanning device has an optical scanning system (1, 5, 6, 7) for repeatedly scanning a recording surface of a record carrier (9) in the form of a tape by means of a first (3) and a second (2) radiation beam. The first (3) and the second (2) radiation beam form a first (11) and a second (12) scanning spot on the recording surface of the record carrier (9). The scanning spots (11, 12) perform synchronous movements along a first (16) and a second (18) scanning path having different given scanning directions, as a result of which the distance, viewed in a direction y transverse to the scanning paths (16 and 19), between the first (11) and the second (12) scanning spot changes during scanning. The scanning device can be used in an optical recording and/or read apparatus. The recording and/or read apparatus further comprises a transport roller (14) for moving the record carrier tape (9) in the direction (y) transverse to the tracks. A detection system (70) converts radiation emanating from the second scanning spot (12) into a corresponding detection signal (S1). A measurement circuit (72) derives a position measurement signal (Sp) based on a deviation in a relationship between the detection signal (S1) and a reference signal (S3) which is indicative of the position of the first scanning spot (11) on the first scanning path (16). The detection signal can further be used for deriving a speed measurement signal (Sv) which is indicative of the speed of the scanning spot in the direction (y) transverse to the scanning path (16) and for deriving a quality measurement signal (Sa) which is indicative of the quality of an information pattern at the location of tracks (75) traversed by the scanning spot (12). If during reading a third scanning spot (4) produces a third scanning spot (13) in such a manner that the second (12) and the third (13) scanning spot are always disposed symmetrically relative to the first scanning spot (11) the corresponding detection signals (S1, S2) can be used for deriving an inclination measurement signal (Ss). This inclination measurement signal (Ss) is indicative of the angle between the tracks (75) on the recording surface and the scanning path (16). <IMAGE> |
