capacitive displacement sensor

• Main Authors: LOACH, ANDREW, THOMAS, DAVID, KENNETH, FERGUSON, GRAHAM, RICHARD
• Format: Patent
• Language: English; French; German
• Published: 27.08.2014
• Subjects: ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVEREDIN A SINGLE OTHER SUBCLASS; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER,MECHANICAL EFFICIENCY, OR FLUID PRESSURE; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR; PHYSICS; TARIFF METERING APPARATUS; TESTING

A displacement responsive device e.g. a measurement probe 110 is disclosed. Displacement of a stylus 130 causes resilient movement of a carriage 134 supported by planar springs 112 and 114. This movement is detected by a capacitance sensor 160, formed from two substantially coaxial tubes. The tubes move in at least three degrees of freedom and changes in their capacitance during the said movement can be determined by a circuit (e.g. Fig 5). Movement in x,y and z directions can be sensed.