LENGTH MEASURING DEVICE AND ARTICLE MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To provide a length measuring device that is advantageous in measuring the length of a moving object.SOLUTION: A length measuring device measuring the length of an object moving in a measurement area in a measurement direction comprises: a detection part 100 that detects light modulated by the Doppler effect of the object; and a processing part 101 that obtains a measured value of the speed of the object on the basis of a signal from the detection part and obtains the length of the object on the basis of the measured value. The processing part specifies a time point corresponding to an end of the object on the basis of the amplitude of the signal, obtains a measured value on the basis of the signal regarding a period determined by the time point, and obtains the length on the basis of the measured value.SELECTED DRAWING: Figure 4 【課題】移動物体の測長を行うのに有利な測長装置を提供する。【解決手段】計測領域を移動する物体の測長を計測方向において行う測長装置は、物体によりドップラ効果で変調された光を検出する検出部１００と、検出部からの信号に基づいて物体の速度の計測値を得、当該計測値に基づいて物体の長さを得る処理部１０１と、を有する。処理部は、当該信号の振幅に基づいて物体の端に対応する時点を特定し、当該時点により定められる期間に関して、当該信号に基づいて計測値を得、当該計測値に基づいて当該長さを得る。【選択図】図４