Electrostatic pressure sensor

Patent metadata

Field	Value
Publication number	US-9228913-B2
Application number	US-201314141654-A
Country	US
Kind code	B2
Filing date	Dec 27, 2013
Priority date	Dec 27, 2012
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

An electrostatic pressure sensor has a supporting diaphragm bonded to be held between first and second pedestal plates, a sensor chip supported on a top face of a center portion of the second pedestal plate. The supporting diaphragm has in the center portion thereof a large-diameter hole that forms a slit-shaped space between the first and second pedestal plates. The first pedestal plate has at least one inlet hole, for the fluid being measured, connecting to the slit-shaped space. The second pedestal plate has at least an outlet hole, connecting to the slit-shaped space, for directing the fluid being measured to the pressure-sensitive diaphragm of the sensor chip. The pedestal plate has an inlet hole of the first pedestal plate and an outlet hole of the second pedestal plate do not overlap each other in the direction of thickness of the first and second pedestal plates.

First claim

The invention claimed is:

1. An electrostatic pressure sensor comprising:
a sensor chip that detects, as a change in electrostatic capacitance, a change in a pressure-sensitive diaphragm that flexes by bearing a pressure of the fluid being measured;
a pedestal plate that supports the sensor chip; and
a supporting diaphragm that supports the pedestal plate, wherein
the pedestal plate is made from a first pedestal plate and a second pedestal plate,
the supporting diaphragm is bonded in a state wherein it is held between the first pedestal plate and the second pedestal plate,
the sensor chip is supported on the top face of the center portion of the second pedestal plate,
the supporting diaphragm has,
in the center portion thereof, a large-diameter hole that forms a slit-shaped space between the first pedestal plate and the second pedestal plate,

the first pedestal plate has,
a single inlet hole, for the fluid being measured, connecting to the slit-shaped space, and provided in a center portion of the first pedestal plate,

the second pedestal plate has
a plurality of outlet holes, connecting to the slit-shaped space, directing the fluid being measured to the pressure-sensitive diaphragm of the sensor chip, and provided in the peripheral portion thereof at equal distances in the radial direction from the center thereof and with equal spacing in the peripheral direction, and
wherein the inlet hole of the first pedestal plate and the outlet holes of the second pedestal plate do not overlap in the direction of thickness of the first and second pedestal plates.

Assignees

• Azbil Corp

Inventors

• Ishihara Takuya
• Tochigi Hidenobu

Classifications

• G01L19/0627

  Protection against aggressive medium in general · CPC title

• G01L9/0073 Primary

  using a semiconductive diaphragm · CPC title

• G01L19/06

  Means for preventing overload or deleterious influence of the measured medium on the measuring device or vice versa · CPC title

• G01L19/00

  Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges · CPC title

• G01L9/12 Primary

  by making use of variations in capacitance {, i.e. electric circuits therefor} · CPC title