WO2024011757A1

WO2024011757A1 - Temperature and pressure sensor

Info

Publication number: WO2024011757A1
Application number: PCT/CN2022/121860
Authority: WO
Inventors: 王小平; 曹万; 吴林; 梁世豪; 吴培宝; 任增强; 王浩
Original assignee: 武汉飞恩微电子有限公司
Priority date: 2022-07-14
Filing date: 2022-09-27
Publication date: 2024-01-18
Also published as: CN115468686A

Abstract

A temperature and pressure sensor, comprising: a housing in which a closed working cavity is provided; a base plate (3), provided in the housing and dividing the working cavity into an upper cavity on the top side and a lower cavity on the bottom side, a pressure guide hole (30a) being formed on the base plate (3); a joint pipe (14), fixed to one end of the bottom of the housing and communicated with the lower cavity; a circuit board (5), provided on the top surface of the base plate (3); a pressure sensitive element (6), provided on the top surface of the base plate (3) and electrically connected to the circuit board (5), and having a pressure sensitive surface communicated to the lower cavity by means of the pressure guide hole (30a); a temperature sensitive element (7), provided in the joint pipe (14) or extending out from the joint pipe (14) towards one side of the bottom; and a plurality of conductors (8) of which bottoms are connected to connecting terminals (701) of the temperature sensitive element (7) in a one-to-one correspondence manner and top ends respectively penetrate through the base plate (3) and are then electrically connected to the circuit board (5).

Description

temperature pressure sensor

This application claims priority to the Chinese patent application with application number 202210824476.1 filed on July 14, 2022.

Technical field

This application relates to the field of sensor technology, specifically to a temperature and pressure sensor.

Background technique

The statements in this section merely provide background information relevant to the present application and may not constitute prior art.

The temperature and pressure sensor is a sensor that integrates a temperature sensitive element and a pressure sensitive element. Among them, a joint pipe is provided on the sensor to introduce the medium to be measured into the cavity, and the medium to be measured is measured through the temperature sensing element and the pressure sensing element. Due to the existence of temperature gradients, the medium to be measured in the pressure sensor is not the same everywhere; and due to the connector principle, as long as the pressure sensing element is connected to the medium to be measured, accurate pressure can be measured. Therefore, in order to accurately measure the temperature of the medium to be measured, the temperature sensing element needs to be arranged as close as possible to the outer end of the connecting pipe.

In addition, silicon piezoresistive pressure sensors have been widely used due to some recognized excellent properties. Silicon piezoresistive pressure sensors are usually set up as back pressure type, that is, the resistance of the pressure chip is set on the opposite side of the medium to be measured, and the pressure chip is set on the substrate. At the same time, in order to protect the pressure chip, the substrate needs to seal and isolate the inner cavity of the sensor.

The above requirements mean that for a temperature pressure sensor using a silicon piezoresistive pressure sensor, the pressure sensing element and the temperature sensing element must be located on opposite sides of the substrate. In order to process the signals measured by the two, the processing circuit needs to be connected to both respectively. Generally, in order to protect the processing circuit, the processing circuit is usually disposed on a side of the substrate close to the pressure chip. This makes the electrical connection between the temperature sensing element and the processing circuit a problem.

There are two main existing methods to deal with the above problems. One of the methods, such as the integrated pressure and temperature sensors disclosed in CN102980714A and CN107817015A, isolates the temperature sensing element from the medium to be measured through a metal shell with good thermal conductivity, thereby separating the temperature sensing element and the pressure sensing element. There is no need to separate them, but thermally conductive material must be filled between the metal housing and the temperature sensor element. Due to the existence of temperature gradient, the measured temperature data has low accuracy, long response time, and complicates the process.

Another method is as disclosed in CN112611504A, in which the temperature-sensitive element is placed on an insulating seat and electrically connected to the circuit board through conductive elastic pieces and conductive elements (such as metal probes). However, when actually manufacturing the above temperature and pressure sensor, there are the following difficulties: First, the upper end of the conductive elastic piece faces upward and elastically contacts the lower end of the conductive element. The connection between the two can easily lead to failure when used for a long time. This is especially true under conditions; secondly, when sealing conductive components that pass through the substrate, a complex via metallization process needs to be used, that is, first plating with Mo-Mn alloy, then plating with a layer of metallic Ni, and using Au- Cu alloy solder is brazed to achieve transition and adaptation of coefficient of thermal expansion (CTE) to avoid adverse effects of temperature on measurement accuracy.

technical problem

In view of the shortcomings of the existing technology, this application provides a temperature and pressure sensor to reduce the risk of its failure.

Technical solutions

In order to achieve the above purpose, this application provides the following technical solutions:

A temperature and pressure sensor, which includes:

The shell has a sealed working cavity inside;

A base plate, which is arranged in the housing and divides the working cavity into an upper cavity on the top side and a lower cavity on the bottom side; a pressure guide hole is provided on the base plate;

A joint pipe, which is fixed at one end of the bottom of the housing and communicates with the lower chamber;

a circuit board, which is arranged on the top surface of the substrate;

A pressure-sensitive element, which is arranged on the top surface of the substrate and is electrically connected to the circuit board, and its pressure-sensitive surface is connected to the lower cavity through the pressure guide hole;

A temperature-sensitive element, which is arranged in the joint tube or protrudes from the joint tube toward the bottom side;

and a plurality of conductors whose bottoms are connected in one-to-one correspondence with the connection terminals of the temperature-sensitive components. Their top ends are respectively penetrated through the substrate and electrically connected to the circuit board.

In one embodiment, the substrate is made of ceramic.

In one embodiment, the top end of the conductor passes through the via hole opened on the substrate, and is sealed with the via hole by a sealing body, and the sealing body is sintered glass.

In one embodiment, the conductor includes a top section, a transition section and a bottom section integrally connected from the top to the bottom. The top section is located radially outside the joint tube relative to the bottom section; the top section extends from the base plate It passes through the opened via hole, and is sealed with the via hole by a sealing body, and the sealing body is sintered glass.

In one embodiment, both the top section and the bottom section are arranged parallel to the axis of the joint pipe, and the portion of the bottom section close to the bottom end forms a plate body.

In one embodiment, the above-mentioned plurality of conductors are evenly spaced around the axis of the joint tube and are arranged on the meridian plane of the joint tube.

In one embodiment, it also includes a protective sleeve set inside the joint pipe. The protective sleeve includes a pipe body and a disk body vertically fixed on the top of the disk body; the temperature sensitive element is arranged in the protective sleeve or Extend from the protective sleeve toward the bottom side.

In one embodiment, a third step is formed on the inner wall of the housing, and the third step abuts against the bottom end surface of the disk toward the top; the top edge of the disk abuts against the base plate on the bottom.

In one embodiment, the top end of the tube hole of the tube body is expanded to form a buffer cavity.

In one embodiment, the conductor includes a top section, a transition section and a bottom section integrally connected from the top to the bottom. The top section is located radially outside the joint tube relative to the bottom section; the top section extends from the base plate It passes through the opened via hole and is sealed with the via hole by a sealing body. The sealing body is made of sintered glass; the top of the disk body is recessed inward to form a plurality of accommodation cavities; the transition section is provided in in the containing cavity.

In one embodiment, a plurality of clamping feet is provided at the top outer edge of the plate body; the clamping feet are clamped toward the top in a clamping groove provided at the bottom of the base plate.

In one embodiment, a plurality of notches radially facing the temperature-sensitive element are opened on the bottom wall of the protective sleeve.

In one embodiment, the central wall of the protective sleeve is provided with a plurality of ribs distributed at intervals along the circumferential direction of the protective sleeve.

In one embodiment, the protective sleeve is made of elastic material.

In one embodiment, the housing includes an outer shell and a top cover, the bottom end of the outer shell is fixed to the joint tube, the top end of the outer shell forms an edge inward, and the edge presses toward the bottom side of the On the periphery of the housing, a plurality of conductive pins are electrically connected to the circuit board, and the conductive pins pass through the top cover in a sealing manner toward the outside of the housing.

beneficial effects

The functions of this application are mainly reflected in the following aspects:

1. The temperature-sensitive element is directly connected to the circuit board through the conductor through the substrate, eliminating the elastic piece and the insulating seat used to protect the elastic piece, avoiding the risk of contact failure and reducing the difficulty of assembly;

2. In one embodiment, by setting the substrate as a ceramic plate, the temperature drift of the pressure-sensitive element is reduced, the sealing performance between the temperature-sensitive element and the substrate is improved, and the risk of sealing failure is reduced;

3. In one embodiment, by arranging a disk on the top of the protective sleeve, the protective sleeve can be further positioned, and the temperature-sensitive element can be maintained to improve its rigidity and sealing performance.

Description of drawings

Figure 1 is a perspective view of the temperature and pressure sensor of the present application;

Figure 2 is a side view of the temperature and pressure sensor of the present application;

Figure 3 is a plane cross-sectional view along A-A shown in Figure 2 of the temperature and pressure sensor of the present application;

Figure 4 is a perspective cross-sectional view along A-A shown in Figure 2 of the temperature and pressure sensor of the present application;

Figure 5 is a front view of the temperature and pressure sensor of the present application;

Figure 6 is a plane cross-sectional view along B-B shown in Figure 5 of the temperature and pressure sensor of the present application;

Figure 7 is a top view of the temperature and pressure sensor of the present application;

Figure 8 is a three-dimensional cross-sectional view along C-C shown in Figure 7 of the temperature and pressure sensor of the present application;

Figure 9 is a perspective view of a partial structure of the temperature and pressure sensor of the present application;

Figure 10 is a perspective view of the protective sleeve and conductor of the present application;

Embodiments of the invention

The technical solution of the present application will be clearly and completely described below with reference to the accompanying drawings. The following examples are illustrative and are only used to explain the present application and cannot be construed as limiting the present application. In the following description, the same reference signs are used to represent the same or equivalent elements, and repeated descriptions are omitted.

It will be further understood that, as used in this specification and the corresponding claims, the term "and/or" refers to any and all possible combinations of one or more of the listed items.

As shown in Figures 1 to 6, the temperature and pressure sensor of the present application mainly includes a housing (not marked), a joint tube 14, a substrate 3, a circuit board 5, a pressure sensitive element 6, and a temperature sensitive element 7. Among them, a sealed working cavity is provided in the casing. The base plate 3 is arranged in the housing and divides the working cavity into an upper cavity (not labeled) on the top side and a lower cavity (not labeled) on the bottom side.

The housing may be integrated, but it may also be separated for convenience in manufacturing. For example, the housing may include a housing 1 and a top cover 2 with a plurality of conductive pins 9 electrically connected to the circuit board 5 . The conductive pins 9 pass through the top cover 2 sealingly toward the top side, thereby electrically connecting with external electronic equipment. Among them, the housing 1, the top cover 2, the substrate 3, and the circuit board 5 are preferably arranged in a circular shape, but may also be arranged in a rectangular or other suitable shape.

In some optional embodiments, the top cover 2 may include a cover plate 201 and a support tube 202 formed by an edge of the cover plate 201 extending downward. The bottom end of the support tube 202 is supported on the second step 10b formed on the inner wall of the housing 1. The top end of the housing 1 is correspondingly formed with a wrapping 101 facing inward, and the wrapping 101 presses against the periphery of the housing 1 toward the bottom side. In this way, the housing 1, the top cover 2 and the base plate 3 are connected and accurately positioned. Among them, an upward first step 10a is formed on the inner wall of the housing 1, and the bottom surface of the substrate 3 presses the first step 10a against the first step 10a, thereby forming a seal. In one embodiment, a positioning step 203 is formed on the top edge of the top cover 2 , and the edge 101 presses against the positioning step 203 toward the bottom side.

In some other embodiments, the top cover 2 is made of insulating material, and the conductive pins 9 are embedded in the top cover 2 . In one embodiment, the proximal end of the bottom of the conductive needle 9 is enlarged to form an enlarged diameter portion 901, which can prevent the conductive needle 9 from protruding. Wherein, the conductive needle 9 may be a spring probe. It is easy to understand that when measuring the relative pressure, a reference pressure can also be introduced in the upper chamber. For example, the upper chamber can be connected to the atmosphere through a vent hole or a breathable membrane to measure the relative pressure in the lower chamber relative to the reference pressure.

In other alternative embodiments, the connection method of the housing 1 and the top cover 2 can also be other known methods. For example, the housing 1 and the top cover 2 can be detachably connected by snapping.

The joint tube 14 is fixed on the bottom end of the housing and communicates with the lower chamber. When in use, the joint pipe 14 is generally connected to a test container such as a pipe filled with the medium to be measured. Therefore, the outer diameter of the joint pipe 14 perpendicular to its own axis is preferably smaller than the corresponding external size of the shell 1. For example, when the shell When 1 is circular, the outer diameter of the joint tube 14 is smaller than the outer diameter of the bottom of the housing 1 . An annular groove 10d may be provided on the outer wall of the joint pipe 14 close to the housing 1, and a first sealing ring 12 may be provided in the annular groove 10d.

The temperature sensitive element 7 is arranged in the joint pipe 14 to measure the temperature of the medium to be measured in the joint pipe 14 . In some other alternative embodiments, the temperature sensitive element 7 can also be extended from the joint tube 14 toward the bottom side to be exposed to the medium to be measured, so that the temperature of the medium to be measured can be measured more accurately. However, in order to avoid damage to the temperature sensitive element 7, the temperature sensitive element 7 can be slightly protruded outward from the joint tube 14, or slightly retracted inward.

The circuit board 5 and the pressure-sensitive element 6 are fixed to the pressure-sensitive element 6 which is disposed on the top surface of the substrate 3 . The pressure-sensitive element 6 is electrically connected to the circuit board 5 . The pressure-sensitive surface of the pressure-sensitive element 6 is disposed toward the bottom side and faces a pressure guide hole 30a opened on the substrate 3, so that the medium to be measured in the lower chamber can be guided from the pressure guide hole 30a to the pressure-sensitive element 6 Pressure sensitive surface. In one embodiment, the bottom end of the pressure guide hole 30a is expanded to form a bell mouth 30c.

The pressure sensitive element 6 can be a silicon piezoresistive pressure sensitive element, which is usually formed by spreading or sputtering a thin film resistor with a piezoresistive effect on the top surface of a silicon chip, and the thin film resistors are connected to form a Wheatstone bridge; the silicon chip is bonded to on the circuit board, and output electrical signals to the circuit board 5. A processing circuit can be provided on the circuit board 5 to process the above-mentioned electrical signals, and output the measurement results to the outside through the conductive pins 9 . In one embodiment, a corresponding window 50a is opened on the circuit board 5 at the position of the pressure sensitive element 6 to make way for the pressure sensitive element 6 . The circuit board 5 may be provided with a first pad 502 electrically connected to the lower end of the conductive pin 9 . An enclosing frame 501 can be fixed on the top surface of the circuit board 5 to enclose the pressure-sensitive element 6 inside, and a protective gel can be poured into the enclosing frame 501 to protect the pressure-sensitive element 6 .

The temperature sensitive element 7 is electrically connected to the circuit board 5 on the other side of the substrate 3 through a plurality of conductors 8 . The number of conductors 8 is the same as the number of connection terminals 701 of the temperature sensitive element 7 , which is generally two. The top end of the conductor 8 penetrates the substrate 3 and is electrically connected to the circuit board 5 , and the bottom end of the conductor 8 is electrically connected to the connection terminal 701 of the temperature sensitive element 7 accordingly. The temperature sensitive element 7 may have an elongated shape.

Compared with the prior art, the temperature and pressure sensor of the above embodiment avoids the elastic contact of the spring piece, and the conductor directly passes through the substrate and is connected to the circuit board. Therefore, the risk of failure is reduced; at the same time, there is no need to use an insulating seat. The spring tabs are fixed and therefore also easy to manufacture and assemble.

In some other embodiments, the substrate 3 may be made of ceramic. Since silicon materials and ceramic materials have very close CTE, the silicon piezoresistive pressure sensitive element 6 can reduce the temperature-induced drift of measurement results when measuring the pressure of the medium to be measured.

In one embodiment, the top end of the conductor 8 can pass through the via hole 30 b opened on the substrate 3 , and is sealed with the via hole 30 b by the sealing body 11 . The sealing body 11 can be made of sintered glass. Since glass and ceramic materials are both inorganic materials composed of metal oxides, they have a relatively close CTE or can be easily adjusted to a suitable CTE, thereby reducing the damage caused by temperature stress. For example, multiple temperature cycles may cause cracks or even cracking in the glass, thereby affecting the sealing performance; more importantly, it can avoid the complicated process of sealing the via holes of the metal and ceramic substrates in the existing technology. Hole metallization process greatly reduces cost and process complexity.

Please refer to FIGS. 9 and 10 . In the above embodiments, the conductor 8 optionally includes a top section 801 , a transition section 802 and a bottom section 803 that are integrally connected from the top to the bottom. The top section 801 is located radially outside the joint tube 14 relative to the bottom section 803 . The top section 801 passes through the via hole 30b opened in the substrate 3, and is sealed with the via hole 30b by the sealing body 11. The sealing body 11 may be glass sintered from glass powder. Through the multi-stage design, the conductor 8 can have high structural rigidity. In one embodiment, the above-mentioned plurality of conductors 8 are evenly spaced around the axis of the joint tube 14 and are arranged on the meridian plane of the joint tube 14 .

In one embodiment, both the top section 801 and the bottom section 803 can be disposed parallel to the axis of the joint tube 14 . The portion of the bottom section 803 close to the bottom end also forms a plate body 804 to facilitate welding to the connection terminal 701 of the temperature sensitive element 7 .

In each of the above embodiments, the temperature and pressure sensor may also include a protective sleeve 4 set in the joint pipe 14 . The protective sleeve 4 includes a tube body 401 and a disk body 402 vertically fixed on the top of the disk body 402. The temperature sensitive element 7 is arranged in the protective sleeve 4 or protrudes from the protective sleeve 4 toward the bottom side.

Please refer to FIG. 4 . In some other embodiments, a third step 10c is formed on the inner wall of the housing 1 . The third step 10c sealingly abuts against the bottom end surface of the tray 402 toward the top side. The top edge of the disk 402 is sealingly contacted with the bottom surface of the substrate 3 . In this way, while positioning the protective sleeve 4, a better seal can be formed at the outer edge between the lower chamber and the upper chamber.

Please refer to FIG. 3 . In some other embodiments, the top end of the tube hole of the tube body 401 is expanded to form a buffer cavity 40a.

Please refer to FIGS. 7 to 10 . In some other embodiments, the conductor 8 includes a top section 801 , a transition section 802 and a bottom section 803 that are integrally connected from top to bottom. The top section 801 is located radially outside the joint tube 14 relative to the bottom section 803 . The top section 801 passes through the via hole 30b opened in the substrate 3 . The sealing body 11 is sealed with the via hole 30b, and the sealing body 11 is made of sintered glass. The top end of the plate body 402 is recessed inward to form a plurality of accommodation cavities 40b, and the transition sections 802 are disposed in the accommodation cavities 40b. In one embodiment, the transition section 802 is disposed closely in the accommodation cavity 40b, so that the accommodation cavity 40b limits the transition section 802, further improving the stiffness of the conductor 8, and in particular, preventing the conductor 8 from falling on the horizontal plane. Deformation. When the buffer chamber 40 a and the accommodation chamber 40 b are provided at the same time, the pressure fluctuation of the medium to be measured can be further buffered, so as to reduce the damage caused by the pressure fluctuation to the pressure sensitive element 6 .

Please refer to FIG. 6 . In some other embodiments, a plurality of clamping feet 403 are provided at the top outer edge of the tray body 402 . The clipping feet 403 are clipped toward the top into the clipping slot 30d provided at the bottom of the base plate 3 . In one embodiment, both circumferential ends of the clamping groove 30d are circumferentially abutted on one of the above-mentioned clamping legs 403, thereby limiting the circumferential rotation of the clamping legs 403 to position the above-mentioned protective sleeve 4 in the circumferential direction. In one embodiment, the clamping feet 403 can be arranged into two groups, two in each group. There are two slots 30d at the bottom of the base plate 3, and the two clamping feet 403 in each group are connected to one of the above-mentioned slots 30d. middle.

Please refer to FIG. 9 . In some other embodiments, the bottom wall of the protective sleeve 4 is provided with a plurality of notches 404 radially facing the temperature-sensitive element 7 , so that the temperature-sensitive element 7 can even Retracting the inside of the tube body 401 also allows the temperature sensitive element 7 to directly contact the medium to be measured for heat exchange.

In one embodiment, the central wall of the protective sleeve 4 is provided with a plurality of clamping ribs 405 spaced apart along the circumferential direction of the protective sleeve 4. The clamping ribs 405 can be radially close to the inner wall of the joint pipe 14, or It forms an interference fit.

In the above embodiments, the protective sleeve 4 can be further made of elastic material, which can form a better connection between the top end of the disk body 402 and the base plate 3, as well as between the bottom end of the disk body 402 and the third step 10c. The sealing can also partially offset the expansion of the medium to be measured when measuring some specific properties of the medium to be measured, such as partially offset the volume expansion of the urea solution when it freezes, thereby protecting the pressure sensitive element 6 from being too large. Failure under volume stress.

The scope of the disclosure is defined not by the detailed description but by the claims and their equivalents, and all modifications within the scope of the claims and their equivalents are to be construed as being included in the disclosure.

Claims

A temperature and pressure sensor including:

The shell has a sealed working cavity inside;

The base plate (3) is arranged in the housing and divides the working cavity into an upper cavity on the top side and a lower cavity on the bottom side; the base plate (3) is provided with a pressure guide hole (30a);

A joint pipe (14), which is fixed at one end of the bottom of the housing and communicates with the lower chamber;

A circuit board (5), which is arranged on the top surface of the substrate (3);

The pressure-sensitive element (6) is arranged on the top surface of the substrate (3) and is electrically connected to the circuit board (5), and its pressure-sensitive surface is connected to the lower cavity through the pressure guide hole (30a);

The temperature sensitive element (7) is arranged in the joint pipe (14) or protrudes from the joint pipe (14) toward the bottom side;

and a plurality of conductors (8) whose bottoms are connected in one-to-one correspondence with the connection terminals (701) of the temperature-sensitive element (7). The tops of the conductors (8) are respectively passed through the substrate (3) and are electrically connected to the circuit board (5). .
The temperature pressure sensor according to claim 1, wherein the substrate (3) is made of ceramic.
The temperature and pressure sensor according to claim 2, wherein the top end of the conductor (8) passes through the via hole (30b) opened on the substrate (3) and is connected with the via hole (30b). The spaces are sealed by sintered glass.
The temperature and pressure sensor according to claim 2, wherein the conductor (8) includes a top section (801), a transition section (802) and a bottom section (803) integrally connected from top to bottom, the top section (801 ) is located radially outside the joint tube (14) relative to the bottom section (803); the top section (801) passes through the through hole (30b) opened on the base plate (3) and is connected with the through hole (30b). The holes (30b) are sealed by sintered glass.
The temperature and pressure sensor according to claim 4, wherein the top section (801) and the bottom section (803) are both arranged parallel to the axis of the joint tube (14), and the bottom section (803) is close to the bottom section. The end portion forms the plate body (804).
The temperature and pressure sensor according to claim 4, wherein the plurality of conductors (8) are evenly spaced around the axis of the joint tube (14) and are arranged on the meridian plane of the joint tube (14).
The temperature and pressure sensor according to claim 1, further comprising a protective sleeve (4) set in the joint pipe (14), the protective sleeve (4) including a pipe body (401) and a vertical The plate body (402) is fixed on the top of the plate body (402); the temperature sensitive element (7) is arranged in the protective sleeve (4) or extends from the protective sleeve (4) toward the bottom side.
The temperature and pressure sensor according to claim 7, wherein a third step (10c) is formed on the inner wall of the housing, and the third step (10c) abuts against the plate (402) toward the top side. The bottom end surface of the plate body (402) is in contact with the bottom surface of the base plate (3).
The temperature and pressure sensor according to claim 7, wherein the conductor (8) includes a top section (801), a transition section (802) and a bottom section (803) integrally connected from top to bottom, the top section (801 ) is located radially outside the joint tube (14) relative to the bottom section (803); the top section (801) passes through the through hole (30b) opened on the base plate (3) and is connected with the through hole (30b). The holes (30b) are sealed by a sealing body (11), which is made of sintered glass; the top of the plate (402) is recessed inward to form a plurality of accommodation cavities (40b); the transition section (802) is provided in the accommodation cavity (40b).
The temperature pressure sensor according to any one of claims 7 to 9, wherein the protective sleeve (4) is made of elastic material.