Patent ID: 6876209

Claim:
A sensor assembly for sensing angular position of one object relative to another object, said sensor assembly comprising: a transmitter capacitor plate defining a transmitter surface area, said transmitter surface area comprising at least one transmitter electrode; a receiver capacitor plate disposed in stationary, juxtaposed relation to said transmitter capacitor plate, said receiver capacitor plate defining a receiver surface area facing said transmitter surface area, said receiver surface area generally corresponding in size to said transmitter surface area, said receiver surface area comprising at least two receiver electrodes forming at least one receiver electrode pair; a rotor composed of a dielectric material disposed within an air gap between the transmitter and receiver surface areas, said rotor comprising three wedge shaped segments having a common rotor center, wherein a first segment subtends substantially 67.5 degrees about said rotor center, a second segment subtends substantially 67.5 degrees about said rotor center and a third segment subtends substantially 45 degrees about said rotor center, and wherein the first segment is separated from the second segment by a vacancy subtending substantially 45 degrees about said rotor center and wherein the third segment is disposed, relative to said rotor center, diametrically opposite said vacancy in substantially equidistant disposition between to said first and second segments, wherein rotation of said rotor relative to said transmitter and receiver capacitor plates varies capacitance between said at least one transmitter electrode and said at least two receiver electrodes; and means for measuring net charge induced on said at least one receiver electrode pair, wherein the charges indicate the angular position of said rotor relative to said transmitter and receiver capacitor plates.