Capacitance-type displacement measuring device with electrodes having spiral patterns
AssigneeMitutoya Corporation
InventorKouji Sasaki
Life of this patent
Estimating the term…
Abstract
A rotary encoder 10 is composed of a halfway cylindrical stator 11 and a cylindrical rotor 12. The rotor 12 is disposed coaxial with the stator 11 with a predetermined gap. Plural transmitting electrodes 13 with spiral patterns and receiving electrode 14 with a rectangular pattern are formed on the inner surface of the stator 12. The transmitting electrodes 13 and receiving electrode 14 are formed of a FPC substrate 17 with lead lines 15, 16. On the outer surface of the rotor 12, coupling electrode 18 are formed with a spiral pattern so as to be capacitively coupled to the transmitting electrodes 13 and receiving electrode 14. FIG. 4C
Claims11
A capacitance-type measuring device for measuring relative position between first and second elements which are arranged to be relatively movable with a predetermined gap, comprising:
- an array of transmitting electrodes disposed on said first element, alternating signals having different phases from each other being supplied to each transmitting electrode;
- a receiving electrode disposed on said first element such as to be isolated from said array of transmitting electrodes;
- and a coupling electrode disposed on said second element to be capacitively coupled to plural electrodes in said array of transmitting electrodes and said receiving electrode, said receiving electrode being adapted to output an electric signal corresponding to a relative position between said first and second elements, the electric signal being supplied to a measuring circuit, wherein
- one of said first and second elements is an inner member having a cylindrical outer surface, the other is an outer member having an incomplete cylindrical inner surface which is opposed to said outer surface with a predetermined gap, said first and second elements being held to be relatively movable in either axial direction or angular direction, and
- said array of transmitting electrodes and said receiving electrode are disposed on one of said outer surface of said inner member and said inner surface of said outer member, and said coupling electrode is disposed on the other.
A capacitance-type measuring device for measuring relative position between first and second elements which are arranged to be relatively movable with a predetermined gap, comprising:
- an array of transmitting electrodes disposed on said first element, alternating signals having different phases from each other being supplied to each transmitting electrode;
- a receiving electrode disposed on said first element such as to be isolated from said array of transmitting electrodes;
- and a coupling electrode disposed on said second element to be capacitively coupled to plural electrodes in said array of transmitting electrodes and said receiving electrode, said receiving electrode being adapted to output an electric signal corresponding to a relative position between said first and second elements, the electric signal being supplied to a measuring circuit, wherein
- one of said first and second elements is an inner member having a cylindrical outer surface, the other is an outer member having a cylindrical inner surface which is opposed to said outer surface with a predetermined gap, said first and second elements being held to be relatively movable in either axial direction or angular direction,
- said array of transmitting electrodes and said receiving electrode are disposed on one of said outer surface of said inner member and said inner surface of said outer member, and said coupling electrode is disposed on the other, and
- both of said array of transmitting electrodes and said coupling electrode have spiral patterns with the same lead angle.
Dependencies are inferred from the claim text.