Capacitive sensor

• US 6,425,289 B1
• Filed: 04/16/1999
• Issued: 07/30/2002
• Est. Priority Date: 04/17/1998
• Status: Expired due to Fees

• Current Assignee: Micronas Gmbh (TDK Corporation)
• Original Assignee: Micronas Gmbh (TDK Corporation)
• Inventors: Sieben, Ulrich, Giehl, Juergen, Igel, Guenter
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): AW MUSSE, ABDULLAHI H
• Application Number:
  US09/293,067
• Time in Patent Office: 1,201 Days
• Field of Search: 737/15, 737/16, 737/17, 737/18, 737/19, 737/20, 737/21, 737/22, 737/23, 737/24.R, 737/25--28, 361/283.4, 361/283.1, 361/283.2, 361/283.3
• US Class Current: 73/715
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: G01L 9/0075 using a ceramic diaphragm, e.g. alumina, fused quartz, glass

Abstract

A capacitive sensor is described which includes a first electrode remote from a second electrode, wherein the first electrode and the second electrode form a measurement capacitance. The first electrode is arranged on a first substrate member and the second electrode is arranged on a second substrate member. At least one of the electrodes has a spatially resolved structure which allows a spatially resolved measurement of the capacitance. The spatial structure of the electrode may be implemented in form of several mutually parallel stripe-shaped elements or in form of a plurality of spaced-apart elements that are arranged in a two-dimensional pattern. Associated with the electrodes are electronic processing units integrated in the substrate members.

Claims

1. Capacitive sensor comprising:

a first electrode; and

a second electrode remote from the first electrode and facing the first electrode, the first and second electrode forming a measurement capacitance;

the first electrode comprising at least three spaced-apart electrode elements arranged in a two-dimensional pattern to form an electrode structure having a spatial resolution,

a plurality of pre-processors, each pre-processor associated with a respective one of the at least three spaced-apart electrode elements;

a signal of each electrode element being pre-processed by a respective one of the plurality of pre-processors according to a spatial characteristic of the respective electrode element; and

a common processor receiving the pre-processed signals from the pre-processor;

wherein each of the electrode elements cooperates with the second electrode to form a respective measurement dependent capacitor.

2. Capacitive sensor according to claim 1, further comprising:

a first substrate member supporting the first electrode;

a second substrate member supporting the second electrode.

3. Capacitive sensor according to claim 2, further comprising:

a plurality of first electronic circuits disposed on the first substrate member, each first electronic circuit associated with a respective one of the electrode elements,

wherein each first electronic circuit separately pre-processes the signal of the associated electrode element.

4. Capacitive sensor according to claim 3,

wherein a region of the second electrode the second substrate member is formed as a deformable membrane.

5. Capacitive sensor according to claim 4, wherein at least one of the substrate members is made of silicon.

6. Capacitive sensor according to claim 3, further comprising a second electronic circuit integrated in the first substrate member,

wherein the second electronic circuit receives the pre-processed signals from the first electronic circuits and processes the pre-processed signals to supply a spatially resolved output signal.

7. Capacitive sensor according to claim 3, wherein at least one of the electrodes is formed of a conductor section of the electronic circuit.

8. Capacitive sensor according to claim 3, wherein the electronic circuit is arranged underneath the electrode of the substrate member on which the electrode is disposed.

9. Capacitive sensor according to claim 3, wherein the electronic circuit comprises circuit elements capable of producing a measurement signal having a spatial resolution.

10. Capacitive sensor according to claim 9, wherein the circuit elements are associated with respective spaced-apart electrode elements.

11. Capacitive sensor according to claim 2, wherein the second substrate member in the region of the second electrode comprises a deformable membrane.

12. Capacitive sensor according to claim 11, wherein the membrane is equipped with reinforcements or ribs preventing the membrane from oscillating.

13. Capacitive sensor according to claim 11, wherein the membrane is provided with a permanent magnet, wherein an external magnetic field acting on the magnet may counteract a deflection of the membrane caused by an oscillation.

14. Capacitive sensor according to claim 11, wherein the sensor further comprises a damping system capable of preventing the membrane from oscillating.

15. Capacitive sensor according to claim 2, wherein said pre-processor is disposed in said substrate member.

16. Capacitive sensor according to claim 1, wherein the spaced-apart elements of the electrode structure are formed as mutually parallel stripes.

17. Capacitive sensor according to claim 1, wherein the spaced-apart elements are arranged in the form of a checkerboard.

18. Capacitive sensor according to claim 1, wherein the spaced-apart elements comprise circular elements.

19. Capacitive sensor according to claim 1, wherein the spaced-apart elements comprise rectangular elements.

20. Capacitive sensor according to claim 1, wherein the spaced-apart elements comprise polygons.

21. Use of the sensor of claim 1 for sensing at least one of a pressure, a force, an acceleration, a magnetic field and a flow rate.

22. Capacitive sensor according to claim 1, wherein the common processor provides a spatially resolved output signal according to values of the pre-processed signals.

23. Capacitive sensor system comprising:

a substrate member

a first electrode disposed on the substrate member;

a second electrode remote from the first electrode and facing the first electrode,

the first electrode comprising at least three spaced-apart electrode elements arranged in a two-dimensional pattern to form an electrode structure having a spatial resolution, each of the electrode elements cooperating with the second electrode to form a respective measurement-dependent capacitor;

a plurality of pre-processors, each pre-processor located inside the substrate member and associated with a respective one of the at least three spaced-apart electrode elements; and

a common processor receiving pre-processed measurement signals from the plurality of pre-processors and providing a spatially resolved output signal according to values of the pre-processed measurement signals.

24. Capacitive sensor comprising:

a plurality of spaced-apart circuit elements adapted to process independent input signals into separate output signals;

a plurality of first electrodes formed on said circuit elements and providing the input signals;

a plurality of pre-processors, each pre-processor associated with a respective one of the plurality of spaced-apart circuit elements;

a common processor receiving pre-processed signals from the plurality of pre-processors and providing a spatially resolved output signal according to values of the pre-processed signals; and

at least one second electrode disposed on a second sudstrate, said second electrode in cooperation with a first electrode forming a respective capacitor,

wherein said capacitors produce output signals having a spatial resolution.

25. Capacitive sensor comprising:

a housing having at least one opening connected to a reservoir providing at least one of a flow and pressure;

a first electrode;

a second electrode remote from the first electrode and facing the first electrode, the first and second electrode forming a measurement capacitance,

wherein at least one of the first and second electrode comprises a plurality of spaced-apart electrode elements which are arranged in a two-dimensional pattern to form an electrode structure to spatially resolve at least one of the flow and the pressure;

a plurality of pre-processors, each pre-processor associated with a respective one of the plurality of spaced-apart circuit elements; and

a common processor receiving pre-processed signals from the plurality of pre-processors and providing a spatially resolved output signal according to values of the pre-processed signals.