| 摘要 |
Method for the contact-free measurement of the relative motion of an object (14) with respect to a scannable pattern (12), wherein there is produced a scanning beam (31) which scans a pattern segment moving with the object along a scanning path on the pattern in order to generate a scanning signal. In order to easily determine the angle between a fixed reference direction on the object and the displacement direction of the pattern with respect to the object, the present invention proposes to sweep and/or displace in parallel the scanning beam along a guiding curve fixed to the object, the displacement of the scanning beam taking place as a function of the guiding angle so that, in addition to the scanning signal, a line density signal is derived which gives the temporary flow of the reciprocal value of the time interval between the instant scanning pulse and the preceding, optionally defaired scanning pulse, and that the phase location of the line density signal is determined with respect to the guiding angle function. Said phase location corresponds to the searched angle.
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