# US 2014/0150559 A1 · Electrostatic pressure sensor

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- Number: US 2014/0150559 A1
- Document ID: US20140150559A1
- Status: Published application
- Kind: A1
- Application number: 14/092,065
- Filed: 2013-11-27
- Published: 2014-06-05
- Earliest claimed: 2012-11-30
- Assignees: Azbil Corporation
- Applicants: Azbil Corporation
- Inventors: Takuya ISHIHARA; Hidenobu TOCHIGI
- Web page: https://patentgrep.com/patent/US20140150559A1

## CPC

- G01L 9/0075: {using a ceramic diaphragm, e.g. alumina, fused quartz, glass}
- G01L 19/02: Arrangements for preventing, or for compensating for, effects of inclination or acceleration of the measuring device; Zero-setting means (for aneroid barometers G01L7/14)
- G01L 19/147: {Details about the mounting of the sensor to support or covering means}
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)

## Abstract

An electrostatic pressure sensor includes a diaphragm, a sensor pedestal, a cover plate, a stationary electrode, and a movable electrode. The cover plate is bonded to an outer peripheral portion of the diaphragm on the opposite side from the sensor pedestal to form a pressure introduction chamber in cooperation with the diaphragm. The cover plate has a pressure introducing hole that introduces a medium to be measured into the pressure introduction chamber from a direction that is perpendicular to a surface of the diaphragm. The pressure introducing hole is arranged so as to be positioned in a range of between 50.0% and 70.0% from the center of the diaphragm along a direction of the surface of the diaphragm, when the radius of the diaphragm is defined as 100%.

## Claims

### Claim 1

An electrostatic pressure sensor comprising:
a diaphragm having a center portion that dislocates in accordance with a pressure of a medium to be measured;
a sensor pedestal that secures a peripheral edge portion of the diaphragm, to form a reference vacuum chamber in cooperation with the diaphragm;
a cover plate, bonded to an outer peripheral portion of the diaphragm on the opposite side from the sensor pedestal, to form a pressure introduction chamber in cooperation with the diaphragm;
a stationary electrode that is formed on a surface of the sensor pedestal on the reference vacuum chamber side; and
a movable electrode that is formed on a surface of the diaphragm on the reference vacuum chamber side, facing the stationary electrode, wherein
the cover plate has a pressure introducing hole that introduces the medium to be measured into the pressure introduction chamber from a direction that is perpendicular to the surface of the diaphragm, and
the pressure introducing hole is arranged so as to be positioned in a range of between 50.0% and 70.0% from the center of the diaphragm along a direction of the surface of the diaphragm, when the radius of the diaphragm is defined as 100%.

### Claim 2 (depends on 1)

The electrostatic pressure sensor as set forth in claim 1, wherein
the pressure introducing hole is arranged in a plurality of holes in positions on a circle that encompass the center of the diaphragm.

### Claim 3 (depends on 1)

The electrostatic pressure sensor as set forth in claim 1, wherein
the movable electrode comprises
a pressure sensing side movable electrode that is formed so that the center thereof is coincident with the center of the diaphragm, and
a reference side movable electrode that is formed so as to be to the outside of the pressure sensing side movable electrode, and
the stationary electrode comprises
a pressure sensing side stationary electrode that is formed so as to face the pressure sensing side movable electrode, and
a reference side stationary electrode that is formed so as to face the reference side movable electrode.