JP4072973B2 - Pressure transducer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure transducer having a sensor element for detecting pressure, and more particularly to a pressure transducer in which a housing and a substrate are integrally formed.
[0002]
[Prior art]
A conventional pressure transducer will be described with reference to FIGS.
[0003]
FIG. 7 is a cross-sectional view of a conventional pressure transducer, and FIG. 8 is a cross-sectional view of another conventional pressure transducer.
A sensor element 65a detects the pressure by converting the displacement of the strain generating portion into an electrical signal, and is fixed to the chip mounting surface 59 provided at the substantially central portion of the housing 55 by a method such as adhesion. A pressure introduction path 53a for introducing a medium to be measured such as air into the strain generating portion of the sensor element 65a and a tube or the like (not shown) to be measured are connected to a substantially central lower portion of the chip mounting surface 59. A connection port 67c is provided, and the pressure chamber 61 is configured by closing the opening of the housing 55 on the opposite side of the connection port 67c with a cover 57a having a pressure introduction path 53b communicating with the atmosphere. ing.
A plurality of terminals 75, 75 are insert-molded on both sides of the housing 55, and the ends of the terminals 75, 75 are arranged so as to be substantially the same height as the surface height of the sensor element 65 a in the pressure chamber 61. The part is exposed and is electrically connected to each terminal (not shown) provided on the sensor element 65a by a method such as wire bonding.
On the other hand, the end portions of the terminals 75 and 75 extending from the side of the housing 55 are fixed to a substrate 63b having a through portion 69c and having various circuit patterns (not shown) formed thereon by a method such as soldering. Thus, the substrate 63b and the housing 55 on which the sensor element 65a is mounted are electrically and mechanically connected.
Here, the pressure transducer 51a of FIG. 7 is suitable for measuring one pressure (hereinafter, referred to as a general measurement), and includes only one connection port 67c, whereas FIG. The pressure transducer 51b of FIG. 8 includes another connection port 67d at the upper part of the housing 55 (more precisely, the cover 57b), and the pressure difference between the two measured media connected to the connection ports 67c and 67d is obtained. There is a difference that it is suitable for measurement (hereinafter referred to as differential pressure measurement).
[0004]
[Problems to be solved by the invention]
However, in such a conventional pressure transducer, since the housing is fixed by soldering the substrate and the terminal, the fixing strength of the soldered portion of the terminal is high when the tube or the like is inserted into or removed from the connection port. In addition to the problem that the fixing portion is peeled off, two steps of connection between the sensor element and the terminal and connection between the terminal and the substrate are necessary, and the assembly process becomes complicated.
Further, in the case of a pressure transducer for measuring differential pressure, since there is a connection port above the housing, an extra installation space is required and it is difficult to reduce the size, and the drawing of a tube or the like becomes complicated. There was a problem.
[0005]
The present invention has been made in order to eliminate these drawbacks in view of the above-described conventional drawbacks. The assembly process is simplified, the installation space is not so much required, the miniaturization is easy, and the use is free. The purpose is to obtain a high pressure transducer.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in a pressure transducer equipped with a sensor element for detecting pressure, a housing having at least two pressure introduction paths in the same direction and having an opening on the other side is provided with several through portions. The chip mounting surface is formed on the end surface of one of the pressure introduction paths in the housing, and the surface height of the sensor element mounted on the chip mounting surface is substantially the same as the substrate surface height. The end face of the other pressure introduction path in the housing is higher than the substrate surface height, and is formed with a step so that the substrate is not exposed, and is surrounded by the step and the inner wall of the housing. By uniformly applying a potting agent to the area where the sensor chip is mounted, the gap between the substrate and the housing is closed, and the opening of the housing is covered. Constitute a pressure transducer by forming a pressure chamber airtight inside the housing by covering with.
Further, in a pressure transducer equipped with a sensor element for detecting pressure, a housing having at least two pressure introduction paths in the same direction and having an opening on the other side is integrally formed on a substrate having several through portions, A chip mounting surface is formed on the end surface of one of the pressure introduction paths in the housing, and an adhesive escape portion is formed on the outer periphery of the chip mounting surface, and the surface height when the sensor element is mounted on the chip mounting surface. Is formed with a step so that the end surface of the other pressure introduction path in the housing is higher than the substrate surface height and the substrate is not exposed. The gap between the substrate and the housing is closed by uniformly applying a potting agent to the region where the sensor chip surrounded by the step and the inner wall of the housing is mounted. Constitute a pressure transducer by forming a pressure chamber airtight inside the housing by covering with a cover the opening of Ujingu.
Furthermore, a pressure converter is configured by providing a protective wall for restricting the flow of the potting agent in the vicinity of the pressure introduction path formed with the step.
[0007]
Embodiment
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0008]
FIG. 1 is a cross-sectional view of a pressure transducer according to a first embodiment of the present invention, and FIG. 2 is a plan view of the pressure transducer with a cover removed.
Reference numeral 63a denotes a substrate having at least two through portions 69a and 69b. The substrate 63a and a housing 5a described later are integrally formed by insert molding or an equivalent method.
Two pressure introduction paths 3a and 3b are provided in the housing 5a toward the lower end of the housing 5a, and connection ports 67a and 67b are provided at the lower ends of the pressure introduction paths 3a and 3b, respectively. It has been. On the other hand, the upper part of the housing 5a has a large opening.
A chip mounting surface 9 for mounting a sensor element 65a for detecting pressure is formed on the upper end surface of the pressure introduction path 3a provided at a position corresponding to the through portion 69a of the substrate 63a. The surface height of the mounted state is configured to be substantially the same as the surface height of the substrate 63a.
In addition, the pressure introduction path end face 15a, which is the upper end face of the pressure introduction path 3b provided at a position corresponding to the other through portion 69b of the board 63a, is a surface of the board 63a so that the board 63a is not exposed. It is higher than the height and formed with a step.
Then, the sensor element 65a is mounted on the chip mounting surface 9, wire bonding is performed with an electrode or the like (not shown) formed on the substrate 63a, the housing inner side walls 13a, 13b, 13c, and the pressure introduction path end surface 15a. By uniformly applying the potting agent 19 to the region where the sensor element 65a surrounded by the side wall due to the step is mounted, the gap between the substrate 63a and the housing 5a is closed, and the upper opening of the housing 5a is opened. By covering with the cover 7, an airtight pressure chamber 21 is formed inside the housing 5a.
[0009]
Since the pressure transducer is configured as described above, the electrical connection between the substrate and the sensor element is sufficient in one wire bonding process, so that the assembly process can be simplified. Further, since the substrate and the housing are integrally formed, the bonding strength is very high, and there is no concern about the insertion and removal of the tube and the like. Furthermore, since the pressure introduction path and the connection port are provided in the same direction in the lower part of the housing, an extra installation space can be eliminated and the tube and the like can be easily routed. In addition, one connection port 67a can be used for general measurement and two connection ports 67a and 67b can be used for differential pressure measurement. Can be increased. Further, since the potting agent also serves as a seal member, it is not necessary to separately perform potting and sealing of the pressure chamber, and an airtight pressure chamber can be easily formed.
[0010]
In addition, as the sensor element 65a, a sensor element using a piezoresistance effect or a sensor using a change in capacitance is generally known, and here, for explanation, a sensor element provided with a glass pedestal 71a is used. The present invention is not limited to this as long as the displacement of the strain generating portion is converted into an electrical signal.
Further, since the potting agent 19 is also filled in the side surface of the sensor element 65a, it is desirable to use a low viscosity, but there is no particular problem as long as it does not adversely affect the characteristics of the sensor element 65a.
The substrate 63a is not limited to this shape, and various amplifier circuits, control units, display units, and the like can be arbitrarily formed on the substrate 63a as well as an arbitrary shape. .
[0011]
Next, another embodiment of the present invention will be described with reference to FIGS.
In addition, about the structure same as the pressure converter of the 1st Embodiment of this invention, the description is abbreviate | omitted by providing the same code | symbol.
[0012]
FIG. 3 is a cross-sectional view of the pressure transducer according to the second embodiment of the present invention, and FIG. 4 is a plan view of the pressure transducer with the cover removed.
The main difference from the pressure transducer according to the first embodiment of the present invention is that the adhesive escape portion 11 is formed on the outer periphery of the chip mounting surface 9 and that the potting agent 19 is formed on a part of the pressure introduction path end surface 15b. The protective wall 17 that restricts the inflow of the liquid is formed, and excess adhesive when the sensor element 65a is fixed to the chip mounting surface 9 flows into the adhesive escape portion 11, and the side surface of the sensor element 65a (accurately) Is not adhered to the side surface of the pedestal 71a, the characteristics of the sensor element 65a are not deteriorated, and the flow of the potting agent 19 can be reliably prevented by the protective wall 17, and the potting agent 19 is prevented. Does not accidentally block the pressure introduction path 3b.
Here, the height of the pressure introduction path end face 15b is formed so low as not to expose the substrate 63a. If there is, there is no problem even if it is formed at the same height as the pressure introduction path end face 15a of the pressure transducer of the first embodiment.
[0013]
FIG. 5 is a cross-sectional view of a pressure transducer according to a third embodiment of the present invention.
The main difference from the pressure transducer of the first embodiment of the present invention is that the connection port 67b (see FIG. 1) is not provided, and the connection port is clearly used only for general measurement. It is shown that such a configuration may be used when unnecessary.
[0014]
FIG. 6 is a cross-sectional view of a pressure transducer according to a fourth embodiment of the present invention.
The main difference from the pressure transducer according to the first embodiment of the present invention is that a sensor element for absolute pressure in which a base 71b does not have a through hole and is joined to a strain generating portion in a vacuum state. It shows that the pressure transducer dedicated to the measurement of absolute pressure can be obtained without changing the configuration of the housing 5d only by using the connection port 67b because the connection port 67b is used.
As described in the pressure transducer according to the third embodiment of the present invention, the connection port 67a can be eliminated.
【The invention's effect】
As described above in detail, in the present invention, the following effects can be obtained.
[0015]
(1) In a pressure transducer equipped with a sensor element for detecting pressure, a housing having at least two pressure introduction paths in the same direction and having an opening on the other side is integrally formed on a substrate having several through portions. The chip mounting surface is formed on the end surface of one of the pressure introduction paths in the housing, and the surface height in the state where the sensor element is mounted on the chip mounting surface is configured to be substantially the same as the substrate surface height, An end face of the other pressure introduction path in the housing is higher than the substrate surface height, and a step is formed so that the substrate is not exposed, and a sensor chip surrounded by the step and the inner wall of the housing is mounted. By uniformly applying a potting agent to the region, the gap between the substrate and the housing is closed, and the housing opening is covered with a cover. Since the pressure transducer is formed by forming an airtight pressure chamber in the part, the electrical connection between the substrate and the sensor element is sufficient in one step of wire bonding, so that the assembly process can be simplified. . Further, since the substrate and the housing are integrally formed, the bonding strength is very high, and there is no concern about the insertion and removal of the tube and the like. Furthermore, since the pressure introduction path and the connection port are provided in the same direction in the lower part of the housing, an extra installation space can be eliminated and the tube and the like can be easily routed. In addition, one connection port can be used for general measurement and two connection ports can be used for differential pressure measurement. it can. Further, since the potting agent also serves as a seal member, it is not necessary to separately perform potting and sealing of the pressure chamber, and an airtight pressure chamber can be easily formed. Furthermore, if necessary, the connection port can be eliminated, and only by mounting a sensor element for measuring absolute pressure, a pressure transducer dedicated to absolute pressure can be obtained, and the degree of freedom in use can be further increased.
[0016]
(2) In a pressure transducer equipped with a sensor element for detecting pressure, a housing having at least two pressure introduction paths in the same direction and having an opening in the other is integrally formed on a substrate having several through portions. The chip mounting surface is formed on the end surface of one pressure introduction path in the housing, and the adhesive escape portion is formed on the outer periphery of the chip mounting surface, and the surface height in a state where the sensor element is mounted on the chip mounting surface. Is formed so that the end face of the other pressure introduction path in the housing is higher than the substrate surface height and the substrate is not exposed, The gap between the substrate and the housing is closed by uniformly applying a potting agent to the region where the sensor chip surrounded by the step and the inner wall of the housing is mounted. Since the pressure transducer is configured by forming an airtight pressure chamber inside the housing by covering the opening of the hood with the cover, the same effect as in (1) can be obtained, and the sensor element can be mounted on the chip. Excessive adhesive when adhering to the mounting surface flows into the adhesive escape area and does not adhere to the side surface of the sensor element (more precisely, the side surface of the pedestal), preventing the characteristics of the sensor element from deteriorating. can do.
[0017]
(3) Since the pressure transducer is configured by providing a protective wall that restricts the flow of the potting agent in the vicinity of the pressure introduction path formed with the step, the flow of the potting agent can be reliably prevented, It is possible to prevent the potting agent from accidentally blocking the pressure introduction path.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a pressure transducer according to a first embodiment of the present invention.
FIG. 2 is a plan view of a state in which the cover of FIG. 1 is removed.
FIG. 3 is a cross-sectional view of a pressure transducer according to a second embodiment of the present invention.
4 is a plan view showing a state in which the cover of FIG. 3 is removed. FIG.
FIG. 5 is a cross-sectional view of a pressure transducer according to a third embodiment of the present invention.
FIG. 6 is a cross-sectional view of a pressure transducer according to a fourth embodiment of the present invention.
FIG. 7 is a cross-sectional view of a conventional pressure transducer.
FIG. 8 is a cross-sectional view of another conventional pressure transducer.
[Explanation of symbols]
1a, 1b, 1c, 1d, 51a, 51b: pressure transducer,
3a, 3b, 53a, 53b: pressure introduction path,
5a, 5b, 5c, 5d, 55: housing,
7, 57a, 57b: cover,
9, 59: chip mounting surface, 11: adhesive escape portion,
13a, 13b, 13c: housing inner side wall,
15a, 15b: pressure introduction path end face,
17: Protective wall, 19: Potting agent,
21a, 21b, 61: pressure chamber; 63a, 63b: substrate;
65a, 65b: sensor elements,
67a, 67b, 67c, 67d: connection port,
69a, 69b, 69c: penetration part,
71a, 71b: pedestal, 75: terminal.

Claims (3)

In a pressure transducer equipped with a sensor element for detecting pressure, a housing having at least two pressure introduction paths in the same direction and having an opening on the other is integrally formed on a substrate having several through portions, and the housing A chip mounting surface is formed on the end surface of one of the pressure introduction paths, and the surface height in a state where the sensor element is mounted on the chip mounting surface is substantially the same as the substrate surface height, The end face of the other pressure introduction path is higher than the substrate surface height, and a step is formed so that the substrate is not exposed, and potting is performed in a region where the sensor chip surrounded by the step and the inner wall of the housing is mounted. By uniformly applying the agent, the gap between the substrate and the housing is closed, and the opening of the housing is covered with a cover. Pressure transducer, characterized in that the formation of the pressure chamber of the fine. In a pressure transducer equipped with a sensor element for detecting pressure, a housing having at least two pressure introduction paths in the same direction and having an opening on the other is integrally formed on a substrate having several through portions, and the housing A chip mounting surface is formed on the end face of one of the pressure introduction paths, an adhesive escape portion is formed on the outer periphery of the chip mounting surface, and the surface height in a state where the sensor element is mounted on the chip mounting surface is the substrate. It is configured to be substantially the same as the surface height, and the end surface of the other pressure introduction path in the housing is higher than the substrate surface height and is formed with a step so that the substrate is not exposed. The potting agent is uniformly applied to the area where the sensor chip surrounded by the inner wall of the housing is mounted, thereby closing the gap between the substrate and the housing. Pressure transducer, characterized in that the formation of the pressure chamber of the airtight inner housing by covering an opening of the grayed with a cover. The pressure transducer according to claim 1 or 2, wherein a protective wall for restricting the flow of the potting agent is provided in the vicinity of the pressure introduction path formed with the step.

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