| 摘要 |
PURPOSE:To detect exactly a reference point by providing a reference point detecting circuit for outputting a prescribed signal by detecting the maximum peak of the intensity of a light beam which is made incident on an optical intensity measuring means from a signal from the optical intensity measuring means of a reference point sensor. CONSTITUTION:A titled device is provided with reference point detecting circuits such as an amplifying circuit 23, a filter 25, a waveform shaping circuit 26, etc. for outputting a prescribed signal of a square wave pulse, etc. by detecting the maximum peak of the intensity of a light beam 31 which is made incident to an optical intensity measuring means 21 from a signal S1 from the optical intensity measuring means 21 of a reference point sensor 7. In such a way, the light beam which is emitted to an object to be detected from the reference point sensor 7 is reflected by a dog 2b so that a position where the sensor 7 has detected a fringe becomes a reference point of an origin, etc. Accordingly, all the detecting operation of the reference point can be executed by an optical action. Therefore, the reference point can be detected very exactly. |
