| 摘要 |
PURPOSE:To perform accurate measurement of the distance by modulating electromagnetic waves whose wavelengths are 0.5mum or more and 5mum or less by frequencies of 100kHz or more and 50MHz or less and detecting the phase delays caused in correspondence with the time length during which the electromagnetic waves go to and return from the object to be measured. CONSTITUTION:The electromagnetic waves, whose wavelengths are 0.5mum or more and 5mum or less, are generated by light emitting diode 2, and modulated by frequencies of 100kHz or more and 5MHz or less from an oscillator 1. Reference luminous flux 4a and reflected luminous flux 4c are recieved by light receiving elements 6 and 7. The phase is delayed in correspondence with the time length during which the electromagnetic waves go to and return from the object to be measured. The electric signal from the light receiving element 7, which has the phase delay, is compared with the electric signal from the light receiving element 6, which has almost no phase delay. The phase difference is converted into a distance signal in a signal detecting means 11 and displayed by a display 12. Therefore the accurate measurement of the distance can be performed. |
