Patent ID: 6654128
Filing Date: 2003-11-25
Classification: G01D

Abstract:
A displacement information detecting apparatus comprising:a displaceable scale member including (i) a first area movable in the displacement direction, provided with a grating portion having a diffraction function as a first light beam dividing function and arranged in the displacement direction, and (ii) a second area, movable in the same direction as the first area, arranged at a position located in a direction perpendicular to the displacement direction relative to the first area and provided with a refracting and splitting function as a second light beam dividing function; a light beam illuminating system for making a light beam enter the first area of said scale member; a reflective member for reflecting the light beam having emerged from the first area to enter the second area; and a plurality of light receiving portions for receiving a plurality of light beams created by the second light beam dividing function in the second area, a signal corresponding to a displacement of the scale member provided by the light received by each of said light receiving portions.