| 摘要 |
PURPOSE:To prevent an error of precision even if the speed of sweep is irregular by measuring the pulse width corresponding to the size of the outside diameter of an object to be measured with the alternating signal formed of the light reflected by a half mirror provided in the optical path for the ray which sweeps the object to be measured. CONSTITUTION:The ray from a light source 1 is made into a parallel sweep ray with a projecting lens 13 according to the rotation of a rotary mirror 12. The parallel sweep ray is condensed by a condenser lens 15 to the 1st sensor 16, from which the pulse signal I having the pulse Tw proportional to the size of the outside diameter D of an object to be measured 14 is generated as an output. The ray split by a half mirror 17 is made incident to a grating 18 and is condensed to the 2nd photosensor 20 by the 2nd condenser lens 19. The alternating signal P corresponding to the slit interval of the grating 18 is outputted. The signal P is multiplied N-fold by a frequency multiplier 21 and is supplied with an AND gate 22 to a counter 24. The count value of the counter 24 is proportional to the size of the outside diameter D of the object 14. |
