JPH0694555A - Pressure sensor - Google Patents

Abstract

PURPOSE:To obtain a pressure sensor applying accurate gas pressure to a silicon membrane for a long period of time and enhanced in reliability by preventing the deformation and deterioration of a material directly coming into contact with gas to be measured due to the swelling and shrinkage thereof to prevent the leakage of the gas to the outside of the sensor and also preventing the deterioration of the characteristics of the sensor due to the adhesion of dust in the gas to be measured. CONSTITUTION:A pressure detection part 7 detecting the difference pressure of both of gas to be measured and a reference fluid is provided between the fluid-to-be-measured introducing part 2 for receiving the pressure of the gas to be measured and the reference fluid introducing part 5 for receiving the pressure of the reference fluid and a partition wall part 13 making the gas to be measured not coming into direct contact with the pressure detection part 7 is provided between the pressure detection part 7 and the gas-to-be-measured introducing part 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor incorporated in a gas meter for measuring gas flow rate and for monitoring whether or not gas supply is normal.

[0002]

2. Description of the Related Art It is considered to use a semiconductor pressure sensor as a small pressure sensor provided in this type of gas meter. A conventional semiconductor pressure sensor will be described by showing a cross section in FIG.

In FIG. 10, reference numeral 1 denotes an outer frame of the pressure sensor, which has a gas introducing portion 2. In the outer frame 2, a sensor case 3 is adhered with an adhesive 4 corresponding to the gas introduction part 2. The sensor case 3 has an air introduction part 5 and a pressure detection part inside. The pressure detecting portion is composed of a silicon substrate 6, a silicon film 7 having a thickness of several microns provided on the silicon substrate 6 by etching, and a semiconductor resistor which is formed on the silicon film 7 and whose resistance value changes due to mechanical strain. It is configured. The silicon film 7 is coated with a gel 8 so as not to come into direct contact with dust and water contained in the gas. A printed circuit board 9 having an electric circuit such as an amplifier circuit formed in the outer frame 1
Are provided and molded with the plastic resin 10. The printed circuit board 9 has an input / output terminal 11. Reference numeral 12 in the figure denotes the tip of the gas introducing portion 2.

In the above structure, the silicon film 7 is mechanically distorted by the pressure difference between the gas pressure applied from the gas inlet 2 and the atmospheric pressure applied from the atmosphere inlet 5. The strain is proportional to the pressure difference between the gas pressure and the atmospheric pressure. When the silicon film 7 is distorted, the resistance value of the semiconductor resistor formed on the silicon film 7 changes in proportion to the magnitude of the strain. Therefore, the differential pressure between the gas pressure and the atmospheric pressure can be measured by detecting, amplifying and outputting the change in the resistance value. The electric circuit formed on the printed board 9 has a function of amplifying the change in the resistance value. The input / output terminals 11 are a power supply terminal for supplying power to the electric circuit on the printed board 9 and the resistance on the silicon film 7, an output terminal for amplifying and outputting a change in resistance value, and a ground terminal.

[0005]

However, in the above-mentioned conventional structure, since the silicon film 7 is structured to receive the pressure of the gas through the gel 8, the direct contact with the gas is
The gel 8, the adhesive 4, and the sensor case 3. Of these, the gel 8 and the adhesive 4 are mainly composed of a polymer material, but are easily touched by the gas because they are directly in contact with the gas, swell and permeate the gas. In the worst case, the molding agent is used. There is a problem that gas leaks to the atmosphere side through a certain plastic resin 10. Also, due to temperature fluctuations,
While the gas is repeatedly liquefied and vaporized, the gel 8, the adhesive 4, the plastic resin 10 and the like are deformed and deteriorated due to swelling and shrinkage, or dust in the gas is attached, resulting in the gas pressure and There was a problem that the pressure difference from the atmospheric pressure could not be measured accurately.

The present invention solves the above problems and prevents deformation and deterioration of the material that is in direct contact with the gas to be measured due to swelling, contraction, etc., to prevent gas leakage to the outside of the sensor, and to prevent gas in the gas to be measured. It is an object of the present invention to realize a highly reliable pressure sensor in which accurate gas pressure is applied to a silicon film for a long period of time by preventing deterioration of sensor characteristics due to dust adhesion.

[0007]

The present invention has the following constitution in order to achieve the above object. As a first solution means, a measured fluid introducing portion, which is provided to measure the differential pressure between the pressure of the measured fluid and the reference pressure, and which introduces the measured fluid, and a reference fluid serving as the reference pressure are introduced. A reference fluid introducing section, a pressure detecting section for detecting the differential pressure provided between the measured fluid introducing section and the reference fluid introducing section,
The pressure detecting portion and the partition wall portion that does not directly contact the fluid to be measured are configured.

As a second means for solving the problems, it is provided for measuring the pressure difference between the pressure of the fluid to be measured and the reference pressure,
The reference fluid is introduced between the fluid to be measured introducing the fluid to be measured, the reference fluid introducing portion to introduce the reference fluid serving as the reference pressure, and the fluid to be measured introducing portion and the reference fluid introducing portion. The pressure detecting section for detecting the differential pressure and the liquid partition section filled between the pressure detecting section and the fluid to be measured introducing section are configured.

As a third means for solving the problems, a measured fluid introducing portion for measuring the differential pressure between the pressure of the measured fluid and the reference pressure, which introduces the measured fluid, and the reference pressure are provided. A reference fluid introducing section for introducing a reference fluid, a pressure detecting section for detecting the differential pressure provided between the measured fluid introducing section and the reference fluid introducing section, the pressure detecting section and the measured fluid. A partition formed of a metal material, a resin, and a polymer material, which is formed between the introducing portion and receives the fluid to be measured and transmits the pressure to the pressure detecting portion, is adopted.

Further, as a fourth solution means, a measured fluid introducing portion, which is provided for measuring the differential pressure between the pressure of the measured fluid and the reference pressure, and which introduces the measured fluid, and the reference pressure. A reference fluid introducing section for introducing a reference fluid, a pressure detecting section for detecting the differential pressure provided between the measured fluid introducing section and the reference fluid introducing section, the pressure detecting section and the measured fluid. Between the pressure detecting part and the partition part, which is formed between the introducing part, receives the fluid to be measured, and transmits the pressure to the pressure detecting part, the metal material or the resin, the partition part of the polymer material, and the pressure detecting part and the partition part. It is configured to include a filled liquid partition wall.

Further, as a fifth solution means, a semiconductor pressure sensor element, an accommodating member having a pressure introducing portion for accommodating the pressure sensor element and introducing the measured pressure, and a pressure introducing portion of the accommodating member. An expandable and contractable diaphragm is formed so as to be airtightly isolated by interposing air between the sensor element and the sensor element.

[0012]

The present invention has the following functions due to the above-mentioned structure. According to the first problem solving means, only the pressure of the fluid to be measured (gas) is accurately transmitted to the pressure detecting portion via the partition wall portion, and the gel of the pressure detecting portion, the adhesive for adhering the sensor case, etc. The molecular material is not touched by the gas and is not attacked by the gas. Therefore, the polymer material does not swell, and the sensor characteristics are not deteriorated due to adhesion of dust in the gas.

According to the second means for solving the problems, only the gas pressure is uniformly and accurately transmitted to the pressure detecting portion through the liquid partition wall portion having a small volume compression ratio, and the polymer material such as gel and adhesive is Since it does not touch the gas directly, it is not attacked by the gas,
Therefore, polymer materials such as gels and adhesives do not swell, and sensor characteristics do not deteriorate due to adhesion of dust in gas.

According to the third means for solving the problems, only the gas pressure is accurately transmitted to the pressure detecting section by the partition section so that the gas pressure is accurately transmitted, and the partition section regulates the opening ratio of the fluid to be measured introduction section. There is a high degree of freedom in design and manufacturing. Further, the polymer material such as gel and adhesive is not directly touched by the gas and is not attacked by the gas. Therefore, the polymer material does not swell and the sensor characteristics are not deteriorated due to the adhesion of dust in the gas.

According to the fourth means for solving the problems, the pressure detecting section is blocked from the gas passage by the partition section and the liquid partition section, only the gas pressure is accurately transmitted, and the polymer material such as gel and adhesive is Since the polymer material is not directly touched by the gas, the polymer material is not swollen, and the sensor characteristics are not deteriorated due to the adhesion of dust in the gas. Further, even when the partition portion is broken, the polymer material is constituted so as not to come into direct contact with the gas by the filled liquid partition wall portion, so that it is not attacked by the gas, and therefore the polymer material does not swell, and Deterioration of sensor characteristics due to the attachment of dust in the gas does not occur.

According to the fifth means for solving the problems, the pressure of the pressure medium to be measured is applied to the sensor element via the diaphragm and the internal air, so that the influence of the pressure medium to be measured on the sensor element is eliminated.

[0017]

Embodiments of the present invention will be described below with reference to FIGS. It should be noted that the same reference numerals are given to the same components as those of the above-mentioned conventional example. Example 1 FIG. 1 is a sectional view of a semiconductor type pressure sensor of Example 1.
The feature of this configuration is that a partition 13 is formed in the sensor case 3 between the gas inlet 2 and the pressure detector. Since the partition wall portion 13 has gas resistance and chemical resistance, it does not cause the swelling phenomenon peculiar to the polymer material, and therefore the volume change,
Since no alteration or the like occurs, the gas does not permeate and no gas leak occurs. The pressure detection unit is composed of the silicon substrate 6, the silicon film 7, the gel 8 and the like. Second Embodiment FIG. 2 is a sectional view of a semiconductor type pressure sensor according to a second embodiment.
The feature of this configuration is that a liquid partition wall portion 14 made of fluorine-based oil is filled between the gas introduction portion 2 portion, that is, the tip 12 of the gas introduction portion and the gel 8 in the pressure detection portion. The tip 12 of the gas introduction portion is formed with a hole diameter that prevents the liquid partition wall (fluorine-based oil) 14 from spilling due to surface tension. The fluorine-based oil has gas resistance and chemical resistance, and has a small volume compression rate, so that the gas pressure can be accurately transmitted to the pressure detection unit. Further, the polymer material of the gel 8 and the adhesive 4 does not cause a swelling phenomenon, and therefore does not cause a volume change, deterioration, etc., and therefore does not cause gas leakage and gas leakage. Third Embodiment FIG. 3 is a sectional view of a semiconductor type pressure sensor of a third embodiment, and FIG. 4 is a detailed sectional view of a gas introducing portion portion of FIG. This structure is characterized in that a metal film (stainless steel 316: thickness 20) is provided between the gas introduction portion 2, that is, the tip 12 of the gas introduction portion and the space having the silicon film 7 which is the pressure sensitive portion of the pressure sensor.
There is a partition 15 made of a diaphragm of about 30 microns. The partition 15 is attached by fixing the partition 15 made of a metal film at the joint 16 between the tip 12 of the gas introduction portion and the outer frame 1 with a rubber packing 17 interposed. The partition 15 of the metal film blocks the gas passage (the tip 12 of the gas introduction part) from the space having the silicon film 7 which is the pressure sensitive part of the pressure sensor, and only the gas pressure is applied to the silicon film 7. Accurately transmitted. The gel 8 and the adhesive 4 are not directly touched by the gas and are not attacked by the gas. Therefore, the gel 8 and the adhesive 4 do not swell, and the deterioration of the sensor characteristics due to the adhesion of dust in the gas does not occur. Further, the partition portion 15 has no restriction on the aperture ratio of the fluid to be measured introduction portion, and has a high degree of freedom in designing and manufacturing.

In this embodiment, the tip 12 of the gas introduction part is
The case where the partition portion 15 for blocking the pressure sensor and the space having the silicon film 7 which is the pressure sensitive portion of the pressure sensor is made of a metal film has been described. However, a resin film partition portion having gas resistance such as polyester resin film is used. May be. Embodiment 4 FIG. 5 is a sectional view of a semiconductor type pressure sensor of Embodiment 4, and FIG. 6 is a detailed sectional view of a gas introducing portion portion of FIG. The feature of this configuration is that the liquid partition (fluorine-based oil) 14 and the partition 15 made of a metal film are provided together. The liquid partition 14 is the same as that of the second embodiment and the partition 15 is the same as that of the third embodiment, and therefore the description thereof is omitted. The tip 12 part of the gas introduction part is formed with a hole diameter that prevents the fluid partition wall part 14 made of fluorine-based oil from spilling out due to surface tension should the partition part 15 of the metal film be damaged or fallen off. ing. The partition 15 of the metal film allows the gas passage (the tip 12 of the gas inlet), the silicon film 7 and the gel 8 to be separated.
It is cut off from the liquid partition wall portion 14 made of fluorine-based oil on the front surface of, and only the gas pressure is accurately transmitted to the silicon film 7. The gel 8 and the adhesive 4 are not directly touched by the gas and are not attacked by the gas. Therefore, the gel 8 and the adhesive 4 do not swell, and the sensor characteristics are not deteriorated due to adhesion of dust in the gas.

Even when the partition 15 made of a metal film is broken, the polymer partition material such as the gel 8 and the adhesive 4 is prevented from coming into direct contact with the gas by the liquid partition wall 14 made of the fluorinated oil. Since it is configured as described above, it is not invaded by the gas, and therefore the same effect as described above can be obtained.

In this embodiment, the tip 12 of the gas introduction part is
Although the case where the partition part for blocking the space having the silicon film 7 which is the pressure sensitive part of the pressure sensor is made of the metal film has been described, the gas resistance of the polyester resin film or the like can be improved similarly to the third embodiment. You may make it the resin film partition part which it has. Fifth Embodiment FIG. 7 is a sectional view of a semiconductor type pressure sensor of a fifth embodiment.
The feature of this configuration is that dangerous gas such as corrosive gas is prevented from directly contacting the sensor element. In particular,
A sensor element 19 made of a silicon semiconductor is provided in the sensor case 18, and the sensor element 19 is bonded to a glass base 20 by an anodic bonding portion 21. The glass base 20 is fixed in the sensor case 18 with an adhesive 25 made of a silicone resin.
The sensor case 18 is made of heat-resistant resin such as PPS resin, the lead frame 30 is insert-molded, and the gold wire 28 is bonded between the lead frame 30 and the sensor element 19. The sensor case 18 is integrally formed with an atmospheric pressure introducing cylinder 18a, and the surface of the sensor element 19 opposite to the atmospheric pressure introducing cylinder 18a is filled with a potting agent 24 so that the sensor element 19 is embedded. There is.

A printed circuit board 27 is attached to the sensor case 18 via a lead frame 30.
The terminal 31 is fixed to. The sensor case 18 is fixed to the center of a housing 29 made of PBT resin or the like, which is a housing member, with an epoxy adhesive 26, and the surface of the sensor element 19 covered with the potting agent 24 faces the pressure introducing cylinder 29a side of the housing 29. It is installed facing. In the housing 29, the sensor case 18 and the filler 23 of silicon resin,
Further, a filler of a soft epoxy resin filled thereon
22 and the atmospheric pressure introducing cylinder 18a and the terminal 31 are formed in a protruding state.

A bellows 32, which is a diaphragm that separates the outside of the atmospheric pressure introducing cylinder 18a from the inside of the housing 29, is fixed to the pressure introducing cylinder 29a of the housing 29. Bellows 32
Is a flexible thin film made of rubber or synthetic resin, and is formed in a cylindrical shape with a bottom. The side surface of the bellows 32 is formed in a wavy shape, and is flexible and deformable. The base end peripheral edge portion 32a of the bellows 32 is fitted into the mounting groove 29b of the inner wall of the pressure introducing cylinder 29a, and is mounted in an airtight state over the entire circumference. Further, as the material of the bellows 32, a material having durability and high safety against toxic gas such as corrosive gas is selected. Air is hermetically housed in the space sandwiched by the bellows 32 and the sensor element 19.

In the operation of the pressure sensor of this embodiment, the pressure introducing cylinder 29a is connected so that the gas pressure to be measured is applied, and the atmospheric pressure introducing cylinder 18a is connected with a rubber pipe or the like so that the atmospheric pressure is applied. Then, when the gas pressure to be measured is applied to the pressure introducing tube 29a, the bellows 32 expands by the pressure, and the bellows is expanded until the pressure of the air in the space between the sensor element 19 and the bellows 32 becomes equal to the gas pressure. 32 transforms. As a result, the measured gas pressure is transmitted to the sensor element 19 via the bellows 32 and the pressure of the air inside thereof, and the pressure of the measured gas is detected.

According to the pressure sensor of this embodiment, dangerous gas such as corrosive gas does not come into direct contact with the sensor element 19, and the number of places where gas leakage may occur in the sensor can be reduced. It can be done and is highly safe. Sixth Embodiment A sixth embodiment will be described with reference to FIG. The characteristic construction of this embodiment is that the peripheral portion of the bellows 32 is fixed by being sandwiched between the pressure introducing cylinders 29a and 29c divided into two parts in the construction of the fifth embodiment. Reference numeral 33 in the drawing denotes a joint portion of the pressure introducing cylinders 29a and 29c divided into two parts.

As a result, the base peripheral edge portion 32 of the bellows 32 is
a is more reliably attached to the pressure introducing tube 29 in an airtight state, the airtightness of the space between the bellows 32 and the sensor element 19 is higher, and the safety can be improved. Seventh Embodiment A seventh embodiment will be described with reference to FIG. The characteristic configuration of this embodiment is that the base end peripheral edge portion 32a of the bellows 32 is sandwiched and fixed by the connecting portion between the sensor case 18 and the housing 29.

As a result, the bellows 32 can be more securely fixed and the number of mounting steps can be reduced.

[0027]

The pressure sensor of the present invention described above has the following effects. (1) The partition that does not directly contact the fluid to be measured with the pressure detection part prevents deformation and deterioration due to swelling and shrinkage of polymer materials such as gels and adhesives, and sensor characteristics due to the adhesion of dust in gas. It is possible to prevent deterioration and realize a highly reliable pressure sensor in which an accurate gas pressure is applied to the silicon film for a long period of time.

(2) The liquid partition wall, which does not directly contact the pressure detection portion and the fluid to be measured, prevents deformation and alteration of the polymer material such as gel and adhesive due to swelling and shrinking, and prevents dust in the gas. It is possible to prevent deterioration of sensor characteristics due to adhesion, and to realize a highly reliable pressure sensor in which accurate gas pressure is applied to the silicon film for a long period of time.

Further, when fluorine-based oil is used for the liquid partition wall, it has gas resistance and chemical resistance, and has a small volume compression rate, so that the gas pressure can be accurately transmitted to the pressure detection section. (3) Since the partition that blocks the space between the pressure detection part and the fluid to be measured introduction part blocks the polymeric material such as gel and adhesive from gas, it prevents deformation and deterioration due to swelling and contraction. In addition, it is possible to prevent deterioration of sensor characteristics due to adhesion of dust in the gas, and it is possible to realize a highly reliable pressure sensor in which an accurate gas pressure is applied to the silicon film for a long period of time. Further, the partition part has no restriction on the opening ratio of the fluid to be measured introduction part, and has a high degree of freedom in design and manufacturing.

(4) Since the liquid partition wall and the partition that block the space between the pressure detection part and the fluid to be measured part block the polymer material such as gel and adhesive from gas, the gel, It can prevent deformation and deterioration due to swelling and shrinkage of polymer materials such as adhesives, and also prevent deterioration of sensor characteristics due to adhesion of dust in gas, and accurate gas pressure is applied to the silicon film for a long period of time. It is possible to realize a highly reliable pressure sensor. In addition, even when the partition is destroyed, the polymer material such as gel and adhesive is protected by the fluorinated oil that forms the filled liquid partition wall, and it is constructed so as not to come into direct contact with the gas, so it is not attacked by the gas. Therefore, there is an effect that the fluid pressure can be accurately detected continuously.

(5) Since the diaphragm is interposed between the sensor element and the pressure introducing portion, the pressure medium to be measured does not directly touch the sensor element, and the gas due to corrosion due to the gas to be measured or cracks due to aging, etc. It is possible to reliably prevent the occurrence of leaks and the like, and it is possible to improve safety and reliability.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a pressure sensor according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a structure of a pressure sensor according to a second embodiment of the invention.

FIG. 3 is a sectional view showing a structure of a pressure sensor according to a third embodiment of the invention.

FIG. 4 is a cross-sectional view showing details of the vicinity of a gas introducing portion of the pressure sensor of the third embodiment.

FIG. 5 is a sectional view showing a structure of a pressure sensor according to a fourth embodiment of the invention.

FIG. 6 is a sectional view showing details of the vicinity of a gas introducing portion of the pressure sensor of the fourth embodiment.

FIG. 7 is a sectional view showing a structure of a pressure sensor according to a fifth embodiment of the invention.

FIG. 8 is a sectional view showing the structure of a pressure sensor according to a sixth embodiment of the present invention.

FIG. 9 is a sectional view showing the structure of a pressure sensor according to a seventh embodiment of the present invention.

FIG. 10 is a sectional view showing the structure of a conventional pressure sensor.

[Explanation of symbols]

 1 Outer Frame 2 Gas Introducing Section (Measured Fluid Introducing Section) 3 Sensor Case 4 Adhesive 5 Air Introducing Section (Reference Fluid Introducing Section) 6 Silicon Substrate 7 Silicon Film (Pressure Detection Section) 8 Gel 13 Partition Section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tokuyoshi Ohashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Toshinori Arai, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Kosaku Kubo 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Takashi Uno 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshiyuki Nakamizo Toyama Prefecture 3158 Shimookubo, Osawano-cho, Kamishinagawa-gun Within Hokuriku Electric Industry Co., Ltd. (72) Inventor Koji Fukuku, 3158 Shimo-Okubo, Osawanocho, Kamishinagawa-gun, Toyama Prefecture In-house Hokuriku Electric Industry Co., Ltd. (72) Kiyoyuki Tanaka, Kamishinagawa-gun, Toyama Prefecture 3158 Okubo Shimo-Osawanocho Hokuriku Electric Industry Co., Ltd. (72) Inventor Hiroyuki Ishiwari Toyama Prefecture Kawagun Osawano Shimookubo 3158 address Hokuriku Electric Industry Co., Ltd. in

Claims (5)

[Claims] 1. A measured fluid introducing portion, which is provided to measure the differential pressure between the pressure of the measured fluid and the reference pressure, and which introduces the measured fluid, and a reference which introduces the reference fluid serving as the reference pressure. A fluid introduction part, a pressure detection part provided between the measured fluid introduction part and the reference fluid introduction part for detecting the differential pressure, and a partition wall part that does not directly contact the pressure detection part and the measured fluid. A pressure sensor composed of. 2. A measured fluid introducing portion, which is provided to measure the differential pressure between the pressure of the measured fluid and the reference pressure, and which introduces the measured fluid, and a reference which introduces the reference fluid serving as the reference pressure. Filling between a fluid introduction part, a pressure detection part provided between the measured fluid introduction part and the reference fluid introduction part for detecting the differential pressure, and between the pressure detection part and the measured fluid introduction part Pressure sensor composed of a liquid partition part. 3. A measured fluid introducing portion, which is provided to measure the differential pressure between the pressure of the measured fluid and the reference pressure, and which introduces the measured fluid, and a reference which introduces the reference fluid serving as the reference pressure. A fluid introducing part, a pressure detecting part provided between the measuring fluid introducing part and the reference fluid introducing part for detecting the differential pressure, and formed between the pressure detecting part and the measured fluid introducing part. A pressure sensor including a partition of a metal material, a resin, or a polymer material that receives the fluid to be measured and transmits the pressure to the pressure detection unit. 4. A measured fluid introducing portion, which is provided for measuring the differential pressure between the pressure of the measured fluid and the reference pressure, and which introduces the measured fluid, and a reference which introduces the reference fluid serving as the reference pressure. A fluid introducing part, a pressure detecting part provided between the measured fluid introducing part and the reference fluid introducing part, for detecting the differential pressure, and formed between the pressure detecting part and the measured fluid introducing part. The pressure-receiving fluid to be measured, a metal material or resin for transmitting pressure to the pressure detection portion, a partition portion of a polymeric material, and a liquid partition wall portion filled between the pressure detection portion and the partition portion. A pressure sensor composed of. 5. A semiconductor pressure sensor element, an accommodating member that accommodates the pressure sensor element and has a pressure introducing portion that introduces a measured pressure, and between the pressure introducing portion of the accommodating member and the sensor element. A pressure sensor having an expandable and contractible diaphragm which is airtightly isolated by interposing air.