Pressure sensor

• US 9,983,081 B2
• Filed: 02/27/2015
• Issued: 05/29/2018
• Est. Priority Date: 03/03/2014
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Oono, Kazuyuki
• Primary Examiner(s): Ha, Nguyen
• Application Number:
  US15/111,494
• Publication Number:
  US 20160334292A1
• Time in Patent Office: 1,187 Days
• CPC Class Codes: G01L 13/026 involving double diaphragm
• CPC Class Codes: G01L 19/14 Housings G01L19/0007, G01L19/0084, G01L19/0092, G01L19/04, G01L19/06 take precedence
• CPC Class Codes: G01L 9/00 Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements G01L11/004 takes precedence; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means measuring differences of two or more pressure values G01L13/00; measuring two or more pressure values simultaneously G01L15/00
• CPC Class Codes: G01L 9/0041 Transmitting or indicating the displacement of flexible diaphragms
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm
• CPC Class Codes: H01L 29/84 controllable by variation of applied mechanical force, e.g. of pressure

Abstract

A pressure sensor includes: a first substrate having first and second diaphragms on one surface provided by first and second recesses on another surface; first and second detecting elements on the first and second diaphragms; a second substrate providing a first reference pressure chamber with the one surface of the first substrate; a third substrate providing a second reference pressure chamber sealing the second recess; and a calculator calculating an offset value by a difference between a reference signal and an inspection signal and detecting a pressure of a measurement medium by a difference between a detection signal and the offset value. The first detecting element outputs the detection signal or the inspection signal according to a pressure difference between a first reference pressure or a reference medium pressure and a measurement medium pressure in the first recess. The second detecting element outputs the reference signal according to a difference between the first reference pressure and and a second reference pressure.

Claims

1. A pressure sensor comprising:

a first substrate having one surface and an other surface opposite to the one surface, and including a first diaphragm on the one surface provided by a first recess on the other surface;

a first detecting element arranged in the first diaphragm on the one surface; and

a second substrate arranged on the one surface of the first substrate, and providing a first reference pressure chamber that is arranged between the first substrate and the second substrate and applies first reference pressure to the one surface of the first diaphragm, wherein;

the first detection element outputs a detection signal according to pressure difference between pressure of a measurement medium introduced to the first recess and the first reference pressure in the first reference pressure chamber;

the first substrate includes a second diaphragm on the one surface provided by a second recess on the other surface; and

the first reference pressure chamber applies the first reference pressure to the one surface of the second diaphragm together with the one surface of the first diaphragm;

the pressure sensor further comprising;

a third substrate attached to the other surface of the first substrate, and including a second reference pressure chamber that seals the second recess and applies second reference pressure to the other surface of the second diaphragm;

a second detecting element arranged in the second diaphragm on the one surface, and outputs a reference signal according to pressure difference between the first reference pressure in the first reference pressure chamber and the second reference pressure in the second reference pressure chamber; and

a calculator calculating an offset value by calculating a differential value between the reference signal and an inspection signal outputted from the first detecting element in accordance with pressure difference between the first reference pressure in the first reference pressure chamber and pressure of a reference medium different from the pressure of the measurement medium to be introduced to the first recess, and detecting the pressure of the measurement medium in accordance with a differential value between the detection signal and the offset value, wherein;

when the first substrate has one direction as a longitudinal direction, the first substrate has one end in the longitudinal direction as a fixed end sealed by mold resin, and an other end in the longitudinal direction as a free end; and

the first diaphragm is arranged closer to the free end than the second diaphragm.

2. The pressure sensor according to claim 1, wherein:

the third substrate is arranged around an opening of the second recess on the other surface of the first substrate.

3. The pressure sensor according to claim 1, wherein:

the first substrate is a semiconductor substrate including a support substrate, an insulating film, and a semiconductor layer, which are stacked in an order thereof; and

the semiconductor layer is arranged on the one surface of the first substrate, and the support substrate is arranged on the other surface of the first substrate.