CN211602261U

CN211602261U - Ceramic pressure sensor

Info

Publication number: CN211602261U
Application number: CN201922438342.2U
Authority: CN
Inventors: 陈君杰; 吴芳莉; 蒋意
Original assignee: Suzhou Transient Semiconductor Technology Co ltd
Current assignee: Suzhou Transient Semiconductor Technology Co ltd
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-09-29
Anticipated expiration: 2029-12-30

Abstract

The utility model discloses a ceramic pressure sensor, this ceramic pressure sensor includes the upper substrate, infrabasal plate and wheatstone bridge, the infrabasal plate is provided with four piezo-resistor along the central line direction, four piezo-resistor form wheatstone bridge through the printing lead wire, and be connected to four diagonal pads, the center of upper substrate is provided with cylindrical cavity, the back printing of upper substrate has the printed circuit layer that links to each other with the metallization through-hole, the infrabasal plate is provided with the metallization through-hole on four angles along diagonal, the conducting resin through pouring into metallization through-hole bottom is connected to together with four metal pads of lower ceramic substrate, realize the electrical connection between wheatstone bridge and the printed circuit layer. The technical scheme solves the problems that the existing pressure sensor cannot realize absolute pressure measurement, the process is complex and the price of a calibration chip is high, has a simple structure and convenient operation, greatly reduces the product cost, and is suitable for industrial popularization and use.

Description

Ceramic pressure sensor

Technical Field

The utility model relates to a pottery pressure sensor can be used to pressure sensor technical field.

Background

A Pressure Transducer is a device or apparatus that senses a Pressure signal and converts the Pressure signal into a usable output electrical signal according to a certain rule. Which is generally composed of a pressure sensitive element and a signal processing unit. Pressure sensors are largely classified into capacitive and piezoresistive types according to their operating principle. Currently, pressure sensors are widely used in various industrial automation control projects as the sensors with the greatest demand in the world. The three main types used by the industry are ceramic pressure sensors, stainless steel pressure sensors and MEMS pressure sensors.

The ceramic has excellent characteristics of high elasticity, corrosion resistance, impact resistance and the like, and the pressure sensor used for manufacturing has better stability and corrosion resistance. However, the existing ceramic pressure sensor has the disadvantages of low cost, incapability of measuring absolute pressure, complex process for measuring absolute pressure, high cost, incapability of measuring polar medium, large packaging volume and complex assembly flow, and limits the application range and industrialization. Therefore, the research on a ceramic pressure sensor with simple structure, exquisite volume and high precision becomes a problem to be solved urgently.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the above problems existing in the prior art and providing a ceramic pressure sensor.

The purpose of the utility model can be realized through the following technical scheme: the utility model provides a ceramic pressure sensor, includes upper substrate, infrabasal plate and wheatstone bridge, the infrabasal plate is provided with four piezo-resistor along the central line direction, four piezo-resistor form wheatstone bridge through the printing lead wire, wheatstone bridge is connected to metal pad through the printing lead wire, the infrabasal plate is provided with four metallization through-holes along diagonal four angles, the center of upper substrate is provided with cylindrical cavity, the back printing of upper substrate has the printed circuit layer that links to each other with the metallization through-hole, be connected to together through the conducting resin who pours into metallization through-hole bottom and four metal pads, realize the electrical connection between wheatstone bridge and the printed circuit layer.

Preferably, each varistor is arranged at a distance from each other.

Preferably, the cylindrical cavity is a cylindrical groove structure.

Preferably, conductive adhesive is injected into each metalized through hole, signals are transmitted to the printed circuit layer through the conductive adhesive, and the conductive adhesive is conductive silver paste.

Preferably, the material of the upper substrate and the material of the lower substrate are both ceramic.

Preferably, the wheatstone bridge is connected with the electronic component through gold wires, the wheatstone bridge comprises a piezoresistor R1, a piezoresistor R2, a piezoresistor R3 and a piezoresistor R4, the piezoresistor R1 and the piezoresistor R4 deform and lengthen under the action of pressure difference, and the resistances increase and become R1+ respectively

And R4+

(ii) a The piezoresistor R2 and the piezoresistor R3 deform but shorten under the action of pressure difference, the resistance is reduced and changed into R2-

And R3-

The negative output voltage terminal and the positive output voltage terminal have a voltage difference.

Preferably, the piezoresistor R1 and the piezoresistor R2 are connected in series to form the left half of the bridge, and the negative end of the output voltage of the bridge is positioned between the piezoresistor R1 and the piezoresistor R2.

Preferably, the piezoresistor R3 and the piezoresistor R4 are connected in series to form a right half bridge of the bridge, an output voltage positive terminal of the bridge is located between the piezoresistor R3 and the piezoresistor R4, the left half bridge and the right half bridge of the bridge are simultaneously connected to ground, and a voltage difference between the output voltage positive terminal and the output voltage negative terminal is a conversion amount of the applied pressure.

The utility model discloses technical scheme's advantage mainly embodies: the pressure sensor structure consists of a ceramic substrate and a Wheatstone bridge, can measure gauge pressure and absolute pressure in the use process, and has the advantages of simple production process, integrated calibration of a chip, small overall packaging volume, low cost and wide application range. The precision of the pressure sensor can reach 0.25 percent, on the basis of the traditional ceramic pressure sensor, the originally adopted capacitor structure is replaced by a Wheatstone bridge, so that the structure can be ensured to have better anti-interference performance on polar media, and meanwhile, the connection of a welding circuit is replaced by through hole metallization and conductive adhesive bonding, so that the reliability and the applicability of the structure are greatly improved.

The technical scheme solves the problems that the existing pressure sensor cannot realize absolute pressure measurement, the process is complex and the price of a calibration chip is high, has a simple structure and convenient operation, greatly reduces the product cost, and is suitable for industrial popularization and use.

Drawings

Fig. 1 is a schematic structural diagram of the ceramic pressure sensor of the present invention.

Fig. 2 is a working schematic diagram of the ceramic pressure sensor of the present invention.

Detailed Description

Objects, advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments. These embodiments are merely exemplary embodiments for applying the technical solutions of the present invention, and all technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the scope of the present invention.

The utility model discloses a pottery pressure sensor, specifically speaking are one kind through the ceramic resistance foil gage of glass bonding realization, a pressure sensor that infrabasal plate and upper substrate are connected promptly. As shown in fig. 1 and 2, a ceramic pressure sensor includes an upper substrate 9, a lower substrate 1 and a wheatstone bridge 100, wherein the lower substrate 1 is printed with four piezoresistors 6 along the central line direction of the lower substrate by using a thick film process, and each piezoresistor is arranged with a gap therebetween.

The four piezoresistors 6 form a wheatstone bridge by means of printed leads 5 which connect the wheatstone bridge also to the metal pads 4 on the diagonals of the lower substrate, on which pads are arranged.

The center of upper substrate 9 is provided with cylindrical cavity 10, cylindrical cavity 10 is cylindrical recess, and the upper substrate is provided with four metallization through-hole 2 on four angles along the upper substrate diagonal, the inside equal metallization of every metallization through-hole 2. Conductive adhesive is injected into each metalized through hole, and signals are transmitted to the printed circuit layer through the conductive adhesive. In the technical scheme, the conductive adhesive is conductive silver paste. The electrical connection between the wheatstone bridge 100 and the printed circuit layer 7 is achieved by the conductive glue 3 injected at the bottom of the metallized via being connected to the four metal pads 4 of the lower substrate.

The back of the upper substrate 9 is printed with a printed circuit layer 7 connected to the metallized through holes 2. The upper substrate 9 and the lower substrate 1 are sintered at high temperature through glass powder to form a glass sealing layer 8, the upper substrate and the lower substrate are bonded together to form a sealing cavity, and the Wheatstone bridge is connected with the through hole through conductive adhesive injected into the bottom of the through hole and is connected with a back circuit board.

In the technical scheme, the upper substrate 9 and the lower substrate 1 are made of ceramic, the thickness range of the upper substrate 9 is 2 mm-3 mm, and the thickness range of the lower substrate 1 is 0.2 mm-0.8 mm. The selection of the ceramic material and the thickness of the upper substrate 9 and the lower substrate 1 enables the ceramic sensor to have rich measuring range and corrosion resistance.

The four piezoresistors 6 can deform the four piezoresistors 6 through the strain transmitted by the lower substrate 9, so that the resistance changes, and then the four piezoresistors are converted into voltage output under the action of a Wheatstone bridge 100 consisting of the four piezoresistors 6.

The Wheatstone bridge 100 is connected with the printed circuit layer 7 through the printed wire 5, the conductive adhesive 3, the metalized through hole 2, and the Wheatstone bridge 100 comprises a piezoresistor R1, a piezoresistor R2 and a piezoresistorThe voltage-sensitive resistor comprises a sensitive resistor R3 and a voltage-sensitive resistor R4, wherein the voltage-sensitive resistor R1 is 10, the voltage-sensitive resistor R2 is 11, the voltage-sensitive resistor R3 is 12, and the voltage-sensitive resistor R4 is 13. The piezoresistor R1 and the piezoresistor R4 deform and lengthen under the action of pressure difference, the resistance increases and becomes R1 +respectively

And R4+

And R3-

The output voltage negative terminal 14 and the output voltage positive terminal 15 are at a voltage difference. When the stress of the lower ceramic substrate 1 changes, the four piezoresistors 6 are driven to deform together, so that the resistance value of the resistor changes, and the voltage applied to the resistor changes.

The piezoresistor R1 and the piezoresistor R2 are connected in series to form a left half bridge, namely a left half bridge, and the output voltage negative terminal 14 of the bridge is positioned between the piezoresistor R1 and the piezoresistor R2. The piezoresistor R3 and the piezoresistor R4 are connected in series to form a right half bridge of the bridge, the right half bridge is also called as a right half bridge, the output voltage positive end 15 of the bridge is positioned between the piezoresistor R3 and the piezoresistor R4, the left half bridge and the right half bridge of the bridge are connected with the ground end 16 together, and the voltage difference between the output voltage positive end 15 and the output voltage negative end 14 is the conversion quantity of the applied pressure.

The pressure sensor adopts ceramic technology, adopts a sealing structure, a Wheatstone bridge and a printed circuit, can well solve the limitation of the traditional pressure sensor on the pressure range and the measuring medium, and has high integration level, simple assembly structure and lower cost, so that the pressure sensor is popular in the market.

The ceramic pressure sensor can adapt to high-pressure overload, can effectively resist instant pressure impact, has no oil filling and no isolation diaphragm, and can measure fluid media with a small amount of impurities. The pressure sensor is of a vacuum sealing structure, the low pressure type can measure absolute pressure, the high pressure type can measure 10MPa, and the high precision type of the product can reach 0.5%. Compared with the conventional ceramic pressure sensor, the sensor has the advantages of compact and small structure, simple process, capability of measuring absolute pressure, strong overload resistance, addition of a signal processing circuit, wide application range, economic cost and high reliability.

The utility model has a plurality of implementation modes, and all technical schemes formed by adopting equivalent transformation or equivalent transformation all fall within the protection scope of the utility model.

Claims

1. A ceramic pressure sensor, characterized by: comprises an upper substrate (9), a lower substrate (1) and a Wheatstone bridge (100), wherein the lower substrate (1) is provided with four piezoresistors (6) along the central line direction, the four piezoresistors (6) form the Wheatstone bridge through printed leads (5), the Wheatstone bridge is connected to a metal pad (4) through the printed leads,

four metallization through holes (2) are arranged at four corners of the lower substrate along the diagonal line, a cylindrical cavity (10) is arranged at the center of the upper substrate (9), a printed circuit layer (7) connected with the metallization through holes (2) is printed on the back of the upper substrate (9), and the conductive adhesive (3) injected into the bottom of each metallization through hole is connected with four metal pads together, so that the Wheatstone bridge (100) is electrically connected with the printed circuit layer (7).

2. The ceramic pressure sensor of claim 1, wherein: every piezo-resistor is all the clearance setting each other.

3. The ceramic pressure sensor of claim 1, wherein: the cylindrical cavity (10) is of a cylindrical groove structure.

4. The ceramic pressure sensor of claim 1, wherein: conductive adhesive is injected into each metalized through hole, signals are transmitted to the printed circuit layer through the conductive adhesive, and the conductive adhesive is conductive silver paste.

5. The ceramic pressure sensor of claim 1, wherein: the upper substrate (9) and the lower substrate (1) are made of ceramics.

6. The ceramic pressure sensor of claim 1, wherein: the Wheatstone bridge is connected with the electronic element through gold wires and comprises a piezoresistor R1, a piezoresistor R2, a piezoresistor R3 and a piezoresistor R4, wherein the piezoresistor R1 and the piezoresistor R4 are deformed and lengthened under the action of pressure difference, and the resistances are increased and respectively changed into R1+

And R4+

And R3-

7. The ceramic pressure sensor of claim 6, wherein: the piezoresistor R1 and the piezoresistor R2 are connected in series to form the left half branch of the bridge, and the negative end of the output voltage of the bridge is positioned between the piezoresistor R1 and the piezoresistor R2.

8. The ceramic pressure sensor of claim 6, wherein: the piezoresistor R3 and the piezoresistor R4 are connected in series to form a right half bridge of the bridge, the positive end of the output voltage of the bridge is positioned between the piezoresistor R3 and the piezoresistor R4, the left half bridge and the right half bridge of the bridge are simultaneously connected with the ground end, and the voltage difference between the positive end of the output voltage and the negative end of the output voltage is the conversion quantity of the applied pressure.