# US 2014/0152325 A1 · Displacement amount monitoring electrode structure

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- Number: US 2014/0152325 A1
- Document ID: US20140152325A1
- Status: Published application
- Kind: A1
- Application number: 14/236,966
- Filed: 2011-08-09
- Published: 2014-06-05
- Earliest claimed: 2011-08-09
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Inventors: Katsutoshi Narita
- Web page: https://patentgrep.com/patent/US20140152325A1

## CPC

- G01B 7/14: for measuring distance or clearance between spaced objects or spaced apertures (G01B7/30 takes precedence)
- B81B 3/0086: {Electrical characteristics, e.g. reducing driving voltage, improving resistance to peak voltage}
- G01C 19/5733: Structural details or topology
- B81B 2201/033: Comb drives
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00)
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)

## Abstract

The displacement amount monitoring electrode structure includes a fixed electrode and a movable electrode each having a comb-teeth shape including a base part and electrode fingers extending from the base part in a direction parallel to a substrate. The fixed electrode and the movable electrode face each other such that the electrode fingers are meshed together. The fixed electrode is fixed to the substrate and the movable electrode can be displaced in the direction. The displacement amount monitoring electrode structure monitors a displacement amount of a detection mass to be driven at a target amplitude based on a change amount of a capacitance between the fixed electrode and the movable electrode. A change sensitivity of the change amount of the capacitance with respect to a displacement amount of the movable electrode, becomes larger after the displacement of the movable electrode reaches a target amount corresponding to the target amplitude.

## Claims

### Claim 1

A displacement amount monitoring electrode structure comprising a fixed electrode and a movable electrode each having a comb-teeth shape including a base part and electrode fingers extending from the base part in a predetermined axis direction parallel to a substrate, the fixed electrode and the movable electrode facing each other such that the electrode fingers of the fixed electrode and the electrode fingers of the movable electrode are meshed together, the fixed electrode being fixed to the substrate and the movable electrode being able to be displaced in the predetermined axis direction, wherein the displacement amount monitoring electrode structure monitors a displacement amount of a detection mass to be driven at a target amplitude based on a change amount of a capacitance between the fixed electrode and the movable electrode, wherein
a change sensitivity of the change amount of the capacitance with respect to a displacement amount of the movable electrode in the predetermined axis direction, has a characteristic of increasing after the displacement of the movable electrode in the predetermined axis direction reaches a target displacement amount corresponding to the target amplitude, compared to before the displacement of the movable electrode reaches the target displacement amount.

### Claim 2 (depends on 1)

The displacement amount monitoring electrode structure according to claim 1, wherein
the change sensitivity of the change amount of the capacitance with respect to the displacement amount of the movable electrode from a neutral position in one way of the predetermined axis direction, and the change sensitivity of the change amount of the capacitance with respect to the displacement amount of the movable electrode from the neutral position in another way of the predetermined axis direction, both have the characteristic.

### Claim 3 (depends on 1)

The displacement amount monitoring electrode structure according to claim 1, wherein
at least one of the fixed electrode and the movable electrode is formed such that a change sensitivity of a total area of areas where the electrode fingers of the fixed electrode and the electrode fingers of the movable electrode face each other at a predetermined distance, becomes larger after the displacement of the movable electrode in the predetermined axis direction reaches the target displacement amount compared to before the displacement of the movable electrode reaches the target displacement amount.

### Claim 4 (depends on 3)

The displacement amount monitoring electrode structure according to claim 3, wherein
the fixed electrode and the movable electrode are formed such that a number of parts where the electrode fingers of the fixed electrode and the electrode fingers of the movable electrode face each other at a predetermined distance, increases after the displacement of the movable electrode in the predetermined axis direction reaches the target displacement amount compared to before the displacement of the movable electrode reaches the target displacement amount.

### Claim 5 (depends on 3)

The displacement amount monitoring electrode structure according to claim 3, wherein
at least one of the fixed electrode and the movable electrode is formed such that a length, in a direction perpendicular to the substrate, of areas where the electrode fingers of the fixed electrode and the electrode fingers of the movable electrode face each other at a predetermined distance, becomes longer after the displacement of the movable electrode in the predetermined axis direction reaches the target displacement amount compared to before the displacement of the movable electrode reaches the target displacement amount.

### Claim 6 (depends on 1)

The displacement amount monitoring electrode structure according to claim 1, wherein
at least one of the fixed electrode and the movable electrode is formed such that a gap where the electrode fingers of the fixed electrode and the electrode fingers of the movable electrode face each other, becomes smaller after the displacement of the movable electrode in the predetermined axis direction reaches the target displacement amount compared to before the displacement of the movable electrode reaches the target displacement amount.

### Claim 7 (depends on 1)

The displacement amount monitoring electrode structure according to claim 1, wherein
at least one of the fixed electrode and the movable electrode is formed such that a dielectric constant between the electrode fingers of the fixed electrode and the electrode fingers of the movable electrode facing each other at a predetermined distance, becomes larger after the displacement of the movable electrode in the predetermined axis direction reaches the target displacement amount compared to before the displacement of the movable electrode reaches the target displacement amount.