| 摘要 |
PURPOSE:To obtain a measured value similar to the result when a light beam having a small angle of radiation is used, by modulating a signal from a projection part and placing only a corresponding part in a photodetecting state. CONSTITUTION:A control signal is supplied from a control part CT to a light emission part OSG under a measurement start command from a keyboard KB and a modulated light emission driving signal is set out. Further, a synchronous scanning part SC is controlled by the output of the control part CT to supply the light emission driving signal to light emitting element groups A1-An of the projection part PA in order, and photodetecting element groups B1-Bn of the photodetection part PB are put in operation successively. If some of photodetecting elements detects a light beam, its reception signal is detected by a photodetection part DET. The height of an oject C of measurement is calculated by the control part CT according to whether the detection signal is present or not, and the measurement data is displayed on a display part DSP. |
