Patent ID: 6292001
Filing Date: 2001-09-18
Classification: G01B,G01D

Abstract:
A capacitance-type displacement measuring apparatus, comprising:a first scale and a second scale arranged opposing to each other and being relatively movable in a measurement axis direction;a transmitting electrode array, formed on said first scale, consisting of a plurality of transmitting electrode units arranged in a basic period in said measurement axis direction, each transmitting electrode unit consisting of n transmitting electrodes arranged in said measurement axis direction for receiving respective phase signals of n-phase transmission signals (where n denotes an integer of 2 or more);at least one receiving electrode disposed on said first scale adjacent to said transmitting electrode array in the direction perpendicular to said measurement axis; anda plurality of coupling electrodes arranged on said second scale in the same period as said basic period in said measurement axis direction so as to capacitively couple with said transmitting electrode units and receiving electrode on said first scale; whereinsaid receiving electrode has in said measurement axis direction a width equal to an integral multiple of said basic period and smaller than a width of said transmitting electrode array, both ends in the width direction of said receiving electrode being located inwardly relative to both ends of said transmitting electrode array, at least parts of said both ends of said receiving electrode close to said transmitting electrode array being cut off.