Patent ID: 6791699
Filing Date: 2004-09-14
Classification: G01D

Abstract:
An optical displacement-measuring apparatus, comprising a scale on which optical gratings formed along a first axis and a second axis crossing said first axis, and a sensor head arranged opposite to said scale and relatively movable along said first and second axes, said sensor head including a photosensitive unit for optically detecting a relative movement to provide a displacement signal, wherein said photosensitive unit comprises:a substrate; and a first to fourth photosensitive device arrays formed with a semiconductor film deposited on said substrate and arranged along said first and second axes, said first and second photosensitive device arrays are arrayed along the first axis at a certain pitch to provide displacement signals corresponding to a displacement along said firstaxis, said third and fourth photosensitive device arrays are arrayed along the second axis at a certain pitch to provide displacement signals corresponding to a displacement along said second axis, said first and second photosensitive device arrays and said third and fourth photosensitive device arrays are diagonally arranged, respectively.