JPS58193431A - Absolute pressure transmitting device - Google Patents

Abstract

PURPOSE:To prevent degradation in a vacuum state, by providing a unitary body of a pressure sensor and a fixing table made of borosilicate glass or the like in a high temperature, high vacuum atmosphere by an anodic bonding method. CONSTITUTION:A fixed table 52 comprises a material, which has the similar thermal expansion coefficient as that of Si which forms a pressure sensor 51, e.g. borosilicate glass, and forms a unitary body together with the pressure sensor 51 by an anodic bonding method by which bonding can be performed in a high temperature vacuum. A gap, in which deflection in the measuring range of the pressure sensor 51 can be accommodated, is provided between the central rigid body of the pressure sensor 51 and the fixed table 52. It is desirable that a material, which has approximately the same thermal expansion coefficient and also approximately the same Young's modulus, is used for the pressure sensor 51, a fixed table 52, and a supporting body 53. The anodic bonding characterized by less bonding strain is effective for each bonding. As a result, the degradation in the vacuum state can be prevented, and the device becomes component, light weight, and stable for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absolute pressure transmitter that converts absolute pressure into an electrical signal using a semiconductor pressure sensor, and more particularly to a liquid ring type absolute pressure transmitter used for industrial measurements.

Absolute pressure transmitters measure the differential pressure between the measured pressure and a vacuum, and conventionally, a pressure or differential pressure transmitter is equipped with a 7-hole diaphragm to form a space on one side of the pressure-receiving diaphragm. It is known that the vacuum is sealed in a vacuum and the vacuum is used as a standard. In such an absolute pressure transmitter, the enclosed soybean is pre-filled. , because it is arranged with FPC etc. made of Kuyurei material, high temperature baking is performed when sealing it in a vacuum. Therefore, there is a drawback that vacuum deterioration occurs due to at-gas, and as a result, zero point drift of an absolute pressure transmitter particularly in a low pressure measurement range is likely to occur.

It is an object of the present invention to provide an absolute pressure transmitter that eliminates the above-mentioned drawbacks and is also smaller and easier to manufacture.

In order to achieve the above object, the present invention integrates a fixed base made of borosilicate glass or the like with a conductor diaphragm pressure sensor having a rigid body part in the center by anodic bonding in a high temperature, high vacuum atmosphere. It is something.

Therefore, since there is no 7N object in the vacuum reference chamber formed by the senna and the fixing table, no outgas is generated near room temperature, and deterioration of the vacuum can be prevented. Furthermore, in the present invention, the amplifying section and the joint fitting for mounting the amplifying section are mounted on the side opposite to the seal diaphragm surface of the pressure receiving section main body in a direction perpendicular to the seal diaphragm, thereby producing an absolute pressure transmitter with good stability. I'm trying to get it.

Hereinafter, one embodiment of the present invention will be described based on the drawings. The sensor s50 includes a clean diaphragm type pressure sensor 51 with a single crystal central rigid body portion, which has a thick peripheral edge portion and a central portion on the opposite side to the surface on which the gauge resistance is diffused and formed, and the peripheral edge of the pressure sensor 51. The sensor s50 is welded to the main body 1. The sensor s50 is made up of a fixing base 52 that supports the pressure sensor 51 through a portion thereof, and a seal fitting 54 having a hermetically sealed member that takes out the signal of the pressure sensor 51 to the outside. The fixed base 5
2 is made of a material with a thermal tensile coefficient of 1 similar to that of the silicon forming the pressure sensor +j51, such as borosilicate cR salt glass, and is integrated with the pressure sensor +j51 by an anodic bonding method if it is possible to use it at high temperatures. There is. Further, there is a gap tm between the central rigid body part of the pressure center t51 and the fixed base 52, which allows the pressure center 51 to flex within the measurement pressure range. This makes it possible to achieve long-term stability and small size as described above. A support 53 made of %Fe-N1 alloy or PE-Ni-CO alloy is bonded to the surface of the fixing base 52 opposite to the surface to which the pressure sensor 51 is bonded, and the pressure sensor 51 is bonded through this support 53. The seal is gold, and is dipped in 54#. Pressure sensor +j51. Fixed stand 52. The supporting body 53 should be made of a material that has a coefficient of thermal expansion that is almost the same and a Young's modulus that is approximately equal to 1! It is desirable that each bond be bonded by anodic bonding, which causes less bonding strain.

The main body IK is in contact with the corrugated flexible seal diaphragm 2 so as to form a corner i11 chamber 3t- with the pressure 7+j51 mounting direction of the cool gold 454. This compartment 3 is filled with an insulating but incompressible liquid such as silicone oil.

Pressure sensor of seal fitting 54? The hermetic lead 58 is visible on the side opposite to the side where 51 is attached.
A flexible printed board with a temperature compensation resistor and a connector 6 to the printed board soldered thereto is soldered. A joint fitting for attaching an extension case 11 is connected to the surface of the main body 1 opposite to the seal diaphragm 2, and a cover 5 for holding the connector 6 is connected to the end thereof.

The above structure is made possible by using a long-term stable pressure cassette with a large withstand pressure.In addition, the amplifying section and the joint fittings for mounting it are placed perpendicular to the seal diaphragm of the main body. The structure in which it is installed has the following advantages.

1. The circumferential welded part during assembly can be made into a coaxial circle.

2. Electrical connections are arranged on m-top.

In other words, there is no need to remove the core of parts, IJIII work, or surface surveying,9 and the combined stacking of the parts during assembly is improved, making it more productive and inexpensive. Sru. In addition, the elimination of hermetic glass firing allows the body layer cover of the sealing tool, which has low corrosion resistance, to be used at the same time as the joint fitting for fixing the am, making it even more productive. , you can also try to make it smaller.

Also, the cumulative component cost is the same, pressure cassette 51 and fixed loan 52.
Po = (2
730To)XωXQ−ttXK (1)Qp
= (2730To) XωXQatt
An absolute pressure transmitter that satisfies the relationship (2) can also be used. Here, To is the reference g& (for example, 27C),
Po is the standard! ! The absolute pressure of the reference foot at Ijt, ω is the coefficient of thermal expansion of the filled liquid, and K is the volume of the seal diaphragm -
The pressure coefficient, '-1att, is the total filled liquid state at the standard temperature, Qp is the pressed liquid wax at the standard temperature, and Qatt''Qp+Q.

There is a relationship. where Qo is the volume of the enclosed offering when the seal diaphragm is free. (1) and (2)
If the formula is satisfied, the zero point T due to fIA11 tension of the incoming liquid
MJf, shadow function and zero point offset f:MA can be eliminated mechanically, and therefore a small absolute pressure transmitter with a warm fit can be obtained even with a diaphragm with a large volume-pressure coefficient, that is, a diaphragm with a small diameter. 6. Also, it can be made smaller @ lid.

According to the present invention, as in the above a5i light, the fertile period is stable.

It is possible to obtain an absolute pressure transmitter that is small and highly productive.

[Brief explanation of drawings]

The figure is a -r plane view of the absolute pressure transmission X8-, which is one embodiment of the present invention. l...Pressure receiving part main body, 2...Seal diaphragm, 3
...Separate 1lIII chamber (enclosed g-Arashi), 4.Work joint fittings, 5..Cover, 6..Connector, 11..
jll decorative part case 51... Silicon diaphragm type sensor with center rigid body, 52... Fixing base, 53... Support body, 54... Seal fitting, 55... Vacuum reference chamber, 10
0...Pressure or differential pressure transmitter, 101...7 lunges. Agent patent attorney? i4 wrathful. (:5.,,,,,,-r

Claims (1)

[Claims] 1. A semiconductor diaphragm pressure sensor with a rigid body in the center, a fixing base for fixing this pressure sensor T, a sealing fitting for attaching this duck fixed base, and a pressure sensor for extracting the electric signal obtained by the pressure sensor to an external path. A hermetic lead wrap formed so as to pass through the seal fitting in the screen direction against the diaphragm surface of the sensor/l, a pressure receiving part main body to which the seal fitting is attached, and a KIR attached to the pressure receiving part main body parallel to the diaphragm surface of the pressure sensor. A good seal diaphragm, consisting of an amplifying part that amplifies the electric signal and converts it into a normal signal, seals the space between the pressure sensor and the fixed base in a vacuum to make it a reference plan, and also connects the central rigid body part and the one. A gap is provided between the fixing base and the measuring range of the pressure sensor, and the seal fitting is attached so as to pass through from one surface of the pressure receiving part main body to the other surface, and the amplifying comb is An absolute pressure transmitter in which the pressure sensor is provided on the side opposite to the pressure sensor with respect to the pressure receiving part main body.