| 摘要 |
PURPOSE:To enable prompt setting of the primary angle of incidence by moving an arm toward the primary angle of incidence at a speed related to the phase difference between a reference signal and a detector output after setting a specimen at the primary angle of incidence thereby obtaining an angle of amplitude reflectance. CONSTITUTION:The arm 10 in an arbitrary starting positiok thetax is, in the first stage X, turned at a certain speed toward the position of the primary angle of incidence independently of the phase difference beta between a reference signal from a reference signal generator 8 and an output from a light detecting device 9. At this time, the arm 10 starts at a low speed and is then moved at the maximum speed FMAX. When the arm 10 reaches the position theta, it slows down and stops at the position x1 slightly distant from the position theta. In the second stage Y, the arm 10 is moved toward the position theta in the opposite direction at a speed related to the phase difference beta. When the arm 10 is moved to the position x2 close to the theta, it goes into the third stage Z so that it is further moved to theta satisfactorily compensating for the jitter. Since the arm is operatively connected with the specimen table 6, the specimen 5 is set at the angle of incidence theta. |
