| 摘要 |
PURPOSE:To improve the accuracy of measurement without affected by the variance in used sensors by detecting the angle of parallel rays from the position of the spot light on a photodetecting plate detected with a spot light detecting means converting the parallel rays to spot light. CONSTITUTION:When the reflected rays from a heliostat are made incident in a correct direction, part of reflected rays 7 penetrates through a pinhole 34 provided at the center of a mask plate 32 and makes spot light 36 at the central position of a photodetection plate 33 and therefore, said position is used as a reference. When the angle of the rays 7 deviates from the correct direction, the center of the spot light 36 created by penetrating through the pinhole 34 deviates from the central position. From the rate of the deviation, the angle of parallel rays is detected. |
