JPH0954005A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten the mechanical strength of a pressure sensor, lessen the number of parts, and simplify the manufacturing process of the sensor by unitedly composing a rotating substrate, a pressure introducing port, and a sensor chip. SOLUTION: A positioning pin 15 formed in a pressure introducing port 11 is inserted to a positioning hole 7 of a rotating substrate 3a from the lower part and while a chip fixing part 17 of the pressure introducing port 11 being positioned at almost the center lower part of a hole part 5a of the rotating substrate 3a, the circuit substrate 3a and the pressure introducing port 11 are fixed mutually with an adhesive or by an another method. Further, a sensor chip 67 is fixed with an epoxy type adhesive and an electrode 75 formed on the sensor chip 67 and a substrate electrode 9 formed in the circuit substrate 3a are electrically connected by a wire bonding method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor that detects pressure by the piezoresistive effect.

[0002]

2. Description of the Related Art Conventionally, there has been a pressure sensor as shown in FIGS.

The conventional pressure sensor will be described in detail with reference to FIGS. 19 to 20. In the conventional pressure sensor, an amplifier circuit (not shown) for amplifying the signal of the sensor chip 67 and a temperature compensation circuit (not shown) are used. ), And further, a circuit board 53 having a variable resistor (hereinafter referred to as a trimmer) 85 for setting a pressure value in order to obtain a digital signal such as on / off with an arbitrary pressure value, and the pressure is detected. The pressure detection module 55 to which the pressure sensor module 57 is attached is connected by a flexible board 81 or a flat cable or the like (not shown). In the use state, the pressure detection board 55 to which the pressure sensor module 57 is attached as shown in FIG. 21 is arranged and housed in a case (not shown) so as to be substantially perpendicular to the circuit board 53. Has been done. At this time, since the flexible board 81 is bent, the electrical connection between the pressure detection board 55 and the circuit board 53 is maintained even in such a state. Here, the pressure sensor module 57
This will be described in detail with reference to FIGS. 22 to 23. In the module housing 61, various terminals 63 are insert-molded and a pressure introducing port 59 is integrally provided. At the other end of the pressure introducing port 59, the chip fixing portion 64 that is inside the module housing 61.
A sensor chip 67 to which a glass pedestal 69 is joined
Are fixed by an adhesive or the like, and are configured so that the gas to be measured connected to the pressure inlet 59 is received by the pressure receiving surface 77 of the diaphragm 73 formed on the silicon chip 71. In addition, the pressure receiving surface 77 of the sensor chip 67
A pressure sensor element (not shown) is formed on the diaphragm 73 on the opposite side to the diaphragm 73. When the diaphragm 73 is bent by the pressure of the gas to be measured and the pressure sensor element is distorted, a pressure is applied according to the applied pressure. Since the resistance value of the sensor element changes, the pressure to be measured can be detected by utilizing this change in resistance value. The signal of the sensor chip 67 is supplied to the chip electrode 75 formed on the sensor chip 67,
The sensor chip 67 and various terminals 63 are electrically connected by wire bonding the terminal electrodes 76 of the terminals 63 that are insert-molded in the module housing 61. Further, after the wire bonding is performed, the sensor chip 67 and the terminal electrode 7 are
The pressure sensor module 57 is configured by performing processing such as potting on 6 and the like as needed, and mounting the module cover 65 on the bottom of the module housing 61.

[0004]

However, the conventional pressure sensor has the following drawbacks.

A sensor chip 67 for detecting pressure is housed in the pressure sensor module 57, and the sensor chip 6
Since the temperature compensating circuit (not shown) provided to perform temperature compensation of No. 7 is formed on the circuit board 53, the sensor chip 67 and the circuit board 53 have different operating environment temperatures, and the circuit board 53 is different. The temperature compensating circuit (not shown) formed in the above does not function properly, resulting in low reliability. Further, not only the assembly of the pressure sensor 51 but also the assembly of the pressure sensor module 57 is separately required, so that the number of manufacturing processes and the number of parts are increased, and many assembly failures occur.

In order to obtain a digital output according to an arbitrary set pressure, it is necessary to provide a variable resistor (trimmer) 85 for setting a pressure value on the circuit board 53, but the pressure sensor module 57 is attached. Pressure detection board 55
And the circuit board 53 to which the trimmer 85 is attached are separately configured via the flexible board 81, so that when the pressure sensor 51 is housed in a case or the like (not shown), Pressure inlet 59,
Since the relative position with respect to the trimmer 85 attached to the circuit board 53 is not fixed, the storage work is difficult and the miniaturization is difficult. Further, during the storage work, an excessive force acts on the connection portion (A) 83 and the connection portion (B) 84 of the flexible substrate 81, the pressure detection substrate 55, and the circuit board 53, so that the connection portion (A) 83, The electrical connection and the mechanical connection of the connection portion (B) 84 are likely to have a problem, the durability is poor, and the automation of the assembly is difficult.

The present invention has been made in view of the above-mentioned conventional drawbacks.
It is an object of the present invention to provide a compact, lightweight, highly reliable and durable pressure sensor having high mechanical strength, a small number of parts, a simplified manufacturing process, easy automation.

[0008]

In order to achieve the above object, the present invention provides a pressure sensor for detecting pressure by a piezoresistive effect, wherein a circuit board having a hole or a notch and the hole or the notch are provided. A chip fixing portion is provided at a corresponding position, a sensor chip is fixed to the chip fixing portion, a pressure introducing port is fixed to the circuit board, electrodes formed on the sensor chip and the circuit board are formed. The pressure sensor is configured by being electrically connected to the electrodes by wire bonding. Further, a pressure sensor is constructed by providing a zero point adjusting circuit or a span adjusting circuit and a temperature compensating circuit of the sensor chip on the circuit board. Furthermore, a large number of electric circuits are formed on the circuit board, and by laser cutting the circuit selection pattern formed on the circuit board according to the application,
A circuit board is provided with circuit selection means for selecting various electric circuits, and a chip cover that covers the sensor chip and blocks external light is provided in the hole or notch of the circuit board, and the circuit board and the pressure introduction port are fixed to each other. The pressure sensor is configured by caulking and welding the fixing pin provided in the pressure introducing port.

[0009]

In the pressure sensor constructed as described above, since the pressure introduction port and the sensor chip are integrally formed on the circuit board, the number of parts can be reduced and the mechanical strength can be improved. Since the sensor chip and the temperature compensation circuit have the same operating environment temperature, appropriate temperature compensation can be performed and the reliability of the pressure sensor is improved. Even if a variable resistor (trimmer) for setting the pressure value is provided to obtain a digital signal for an arbitrary set pressure, the relative position between the pressure introduction port and the trimmer will be stable, so move to a case etc. The storage work of can be simplified and automation can be facilitated.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments of the invention shown in the drawings.

In the first embodiment of the present invention shown in FIGS. 1 and 2, 1a is a pressure sensor of the present invention, and 3a is a hole 5.
It is a circuit board provided with an amplifier circuit (not shown) and a temperature compensating circuit (not shown) which are provided with a and a positioning hole 7 and are composed of circuit components (not shown) such as various chip resistors. From the lower part of the positioning hole 7 of the circuit board 3a,
The positioning pin 15 formed in the pressure introducing port 11 is inserted, and the chip fixing portion 17 of the pressure introducing port 11 is arranged in the lower central portion of the hole 5a of the circuit board 3a. The port 11 is fixed by a method such as adhesion. The circuit board 3a and the pressure introducing port 11 may be fixed to each other by caulking and welding the positioning pin 15 without using a method such as adhesion. Further, the sensor chip 67 is fixed on the chip fixing portion 17 of the pressure introducing port 11 by an epoxy adhesive or the like, and the chip electrode 75 formed on the sensor chip 67.
And the board electrode 9 formed on the circuit board 3a are electrically connected by wire bonding. Although the sensor chip 67 to which the glass pedestal 69 is bonded is used in FIG. 2, the sensor chip 67 is not limited to this, and the sensor chip 67 and the chip electrode 7 are not limited thereto.
5, processing such as potting may be performed on the substrate electrode 9 and the like.

In the pressure sensor 1a having the above structure, since the circuit board 3a, the pressure introducing port 11 and the sensor chip 67 are integrally formed, the mechanical strength is high and the durability is excellent, and the number of parts is small. Simplification of the manufacturing process can be achieved. Further, this facilitates the automation of the assembly and reduces the cost.

Since the sensor chip 67 and the circuit board 3a on which the temperature compensating circuit is formed are arranged in substantially the same portion, the use environment temperature becomes the same, and highly accurate temperature compensation can be performed, so that reliability is high. A highly reliable pressure sensor can be obtained.

[0014]

Different Embodiments of the Present Invention Next, different embodiments of the present invention shown in FIGS. 3 to 18 will be described. In addition,
In describing these different embodiments of the present invention,
The same components as those in the first embodiment of the present invention are designated by the same reference numerals, and duplicate description will be omitted.

The second embodiment of the present invention shown in FIGS. 3 to 4 is mainly different from the first embodiment of the present invention in that the hole 5a of the circuit board 3a is replaced by a notch. 5b
Has been formed.

In FIG. 3, reference numeral 3b is a circuit board composed of a printed circuit board (hereinafter referred to as PCB), in which an amplifier circuit and a temperature compensation circuit are formed as in the first embodiment of the present invention. The notch 5b and the positioning hole 7 are provided. From the lower part of the positioning hole 7 of the circuit board 3b, the positioning pin 15 formed in the pressure introducing port 11 is formed.
Is inserted, and the tip of the positioning pin 15 of the pressure introducing port 11 is caulked and welded in a state where the chip fixing portion 17 of the pressure introducing port 11 is arranged substantially in the lower center of the cutout portion 5b of the circuit board 3b. The circuit board 3b and the pressure introduction port 11 are fixed to each other. The circuit board 3b
As for the fixation between the pressure introduction port 11 and the pressure introduction port 11, a method such as adhesion can be used as in the first embodiment of the present invention.

The third embodiment of the present invention shown in FIGS. 5 to 18 is mainly different from the first embodiment of the present invention in that a zero point adjusting circuit (not shown) is provided on the circuit board 3a. ), A span adjusting circuit (not shown) is formed, a plurality of electric circuits (not shown) are formed, and circuit selection means for selecting various electric circuits according to the application is provided. The chip cover 31 is mounted on the circuit board 3a.

In FIG. 5, reference numeral 3a is a circuit board made of PCB. The pressure introducing port 11 is positioned by the positioning hole 7 and the positioning pin 15 as in the first embodiment of the present invention, and the positioning pin 15 is positioned. They are fixed by caulking and welding. Similar to the first embodiment of the present invention, after the sensor chip 67 is fixed to a predetermined position and the sensor chip 67, the chip electrode 75, the substrate electrode 9 and the like are subjected to processing such as potting as necessary, , The chip cover 31 covers the circuit board 3 so as to cover the sensor chip 67.
a. Reference numeral 85 denotes a variable resistor (trimmer) that sets an arbitrary pressure value when the pressure sensor of the present invention is operated as a pressure switch, and is connected to a predetermined circuit provided on the circuit board 3a. This trimmer 85
It can be unnecessary. Here, the mounting of the tip cover 31 will be described in detail with reference to FIGS. 10 to 13. The tip cover 31 is projected by inserting the guide portion 35 of the tip cover 31 into the tip cover insertion portion 8 of the hole 5a and pushing it in as it is. The locking piece 33 engages with the chip cover locking portion 6 located in the hole 5a on the lower surface of the circuit board 3a, and the chip cover 31 is mounted and held on the circuit board 3a. At this time, the guide portion 35 and the like of the chip cover 31 are not
14 to 15, the locking groove 1 is provided at a predetermined position of the pressure introducing port 11 so as to project from the lower surface of the locking groove 1.
9 or a recess (not shown) is formed. FIG.
Is a diagram for explaining the trimming (resistance value adjustment) of the trimming chip resistor 23 that constitutes the zero point adjusting circuit and the span adjusting circuit (not shown), and shows the trimming chip resistor 23 formed on the base 27. , (X1, Y1) to (X
1 ', Y1'), (X2, Y2) to (X2 ', Y
By performing laser cutting from 2 '), (X3, Y3) to (X3', Y3 '), a desired resistance value is obtained and zero point adjustment and span adjustment are performed. FIG. 17 is a front view thereof. FIG. 18 is a diagram for explaining a circuit selection pattern 29 (circuit selection means) that selects variously formed electric circuits (not shown) according to the purpose of use.
A circuit selection pattern 29 formed on the circuit board 3a as shown in FIG.
Various electric circuits are selected by forming the pattern as shown in FIG. In addition, in the third embodiment of the present invention, the method of laser cutting is adopted as the circuit selecting means, but in addition to this, various methods such as constituting the circuit selecting means by a rotary switch may be used. You can

Since the zero point adjusting circuit and the span adjusting circuit are formed on the circuit board 3a, the number of parts can be reduced and the size can be reduced. In addition, since the plurality of electric circuits and the circuit selecting means are provided on the circuit board 3a, it can be used for various purposes and the cost can be reduced.

By mounting the chip cover 31 on the circuit board 3a so as to cover the sensor chip 67, the sensor chip 67 is irradiated with light even when the pressure sensor 1c is not housed in a case (not shown) or the like. This can be prevented and a stable sensor output can be obtained. Moreover, since it is possible to prevent foreign matter from adhering to the sensor chip 67, a pressure sensor having excellent reliability and durability can be obtained.

When the circuit board 3a is provided with the trimmer 85, the pressure introducing port 13 of the pressure introducing port 11 and the trimmer 85 are provided.
Since the relative position with respect to is accurate, storage work in a case or the like is facilitated and automation is facilitated.

[0022]

As is apparent from the above description, the following effects can be obtained in the present invention.

(1) In a pressure sensor for detecting pressure by a piezoresistive effect, a circuit board having a hole or a notch and a chip fixing portion at a position corresponding to the hole or the notch, and the chip fixing The sensor chip is fixed to the portion, and the pressure introduction port fixed to the circuit board and the electrode formed on the sensor chip and the electrode formed on the circuit board are electrically connected by wire bonding. Since the pressure sensor is configured, the mechanical strength and the durability are improved as compared with the conventional circuit board and the pressure detection board having different configurations.
Further, automation of assembly becomes easy to measure. (2) According to the above (1), since the pressure sensor module is not required separately, the number of parts can be reduced and the manufacturing process can be simplified. In addition, manufacturing defects can be reduced,
The cost can be reduced. (3) In a pressure sensor that detects pressure by the piezoresistive effect, a circuit board having a hole or a notch,
The circuit board is provided with a zero-point adjusting circuit or a span adjusting circuit, and a chip fixing portion is provided at a position corresponding to a hole or a cutout portion of the circuit board, and a sensor chip is fixed to the chip fixing portion. Since the pressure sensor is configured by electrically connecting the pressure introduction port fixed to the electrode, the electrode formed on the sensor chip and the electrode formed on the circuit board by wire bonding, Can be reduced and the size can be reduced. (4) In a pressure sensor that detects pressure by the piezoresistive effect, a circuit board having a hole or a notch,
The circuit board is provided with a zero-point adjusting circuit or span adjusting circuit and a temperature compensating circuit for the sensor chip, and a chip fixing portion is provided at a position corresponding to a hole or notch in the circuit board, and the chip fixing portion has a sensor chip. And a pressure introduction port fixed to the circuit board, and an electrode formed on the sensor chip and an electrode formed on the circuit board are electrically connected by wire bonding to form a pressure sensor. Therefore, the operating temperature environment of the sensor chip and the temperature compensating circuit become substantially the same, and the optimum temperature compensation can be performed, so that the reliability can be improved. (5) In a pressure sensor that detects pressure by a piezoresistive effect, a circuit board having a hole or a notch,
The circuit board is provided with a zero point adjusting circuit or a span adjusting circuit and a temperature compensating circuit for the sensor chip, and a plurality of electric circuits are formed on the circuit board. The sensor chip has a chip fixing portion at a position corresponding to the hole or notch of the circuit board, the sensor chip is fixed to the chip fixing portion, and the pressure introducing port is fixed to the circuit board, and the sensor chip is attached to the sensor chip. Since the pressure sensor is configured by electrically connecting the formed electrode and the electrode formed on the circuit board by wire bonding, one pressure sensor can be used for various purposes and mass production is possible. It is possible and the cost can be reduced. (6) In a pressure sensor that detects pressure by a piezoresistive effect, a circuit board having a hole or a notch,
The circuit board is provided with a zero-point adjusting circuit or a span adjusting circuit and a temperature compensating circuit for the sensor chip, and a plurality of electric circuits are formed on the circuit board, and a circuit selection pattern formed on the circuit board according to the application. A circuit selecting means for variously selecting the electric circuit by laser cutting is provided, and a chip fixing portion is provided at a portion corresponding to a hole or notch of the circuit board, and the sensor chip is fixed to the chip fixing portion. The pressure introduction port fixed to the circuit board, the electrode formed on the sensor chip and the electrode formed on the circuit board are electrically connected by wire bonding, and the light from the outside that covers the sensor chip is exposed. Since the pressure sensor is configured by providing the chip cover for blocking the above in the hole or notch of the circuit board, the pressure sensor is affected by light. In without change occurs characteristic of the sensor, since the adhesion of foreign materials to the sensor chip can be prevented, thereby improving the reliability. In addition, since a separate case that blocks light is not required, cost can be reduced, and a transparent (light-transmitting) case can also be used. It is also possible to construct playful products. (7) According to claim 6, the same effects as the above (1) to (6) can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a plan view showing a second embodiment of the present invention.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a plan view showing a third embodiment of the present invention.

FIG. 6 is a front view showing a third embodiment of the present invention.

7 is a sectional view taken along line VII-VII in FIG.

FIG. 8 is a plan view showing the circuit board according to the first embodiment of the present invention.

9 is a sectional view taken along line IX-IX in FIG.

10 is a sectional view taken along line XX of FIG.

FIG. 11 is a plan view showing a chip cover according to a third embodiment of the present invention.

FIG. 12 is a front view showing a tip cover according to a third embodiment of the present invention.

FIG. 13 is a side view showing a tip cover according to a third embodiment of the present invention.

FIG. 14 is a plan view showing a pressure introducing port according to the first embodiment of this invention.

FIG. 15 is a bottom view showing the pressure introducing port according to the first embodiment of this invention.

FIG. 16 is a plan view showing a trimming chip resistor according to a third embodiment of the present invention.

FIG. 17 is a front view showing a trimming chip resistor according to a third embodiment of the invention.

FIG. 18 is an explanatory diagram showing a circuit selection pattern according to the third embodiment of this invention.

FIG. 19 is a plan view showing a conventional pressure sensor.

FIG. 20 is a front view showing a conventional pressure sensor.

FIG. 21 is a front view showing an assembled state of a conventional pressure sensor.

FIG. 22 is a cross-sectional view showing a pressure sensor module of a conventional pressure sensor.

FIG. 23 is a bottom view showing the pressure sensor module as seen through the module cover of the conventional pressure sensor.

[Explanation of symbols]

1a, 1b, 1c: pressure sensor, 3a, 3b: circuit board, 5a: hole, 5b:
Notch part, 6: Tip cover locking part, 7: Positioning hole, 8: Chip cover insertion part, 9:
Substrate electrode, 11: pressure introduction port, 1
3: pressure inlet, 15: positioning pin,
17: chip fixing portion, 19: locking groove,
21: fixed groove, 23: chip resistor for trimming, 25: pattern cut portion, 27: base,
29: Circuit selection pattern, 31:
Chip cover, 33: Locking piece, 35:
Guide part, 36: Notch part, 51:
Pressure sensor, 53: circuit board, 5
5: Pressure detection board, 57: Pressure sensor module, 59: Pressure inlet, 6
1: module housing, 63: terminal,
64: Chip fixing part, 65: Module cover, 67: Sensor chip, 69: Glass pedestal, 71: Silicon chip, 7
3: Diaphragm, 75: Chip electrode, 76: Terminal electrode, 77: Pressure receiving surface, 79: Wire, 81: Flexible substrate, 83: Connection part (A),
84: connection part (B), 85: variable resistor (trimmer).

Claims (6)

[Claims] 1. A pressure sensor for detecting pressure by a piezoresistive effect, comprising a circuit board having a hole or a notch, and a chip fixing portion at a position corresponding to the hole or the notch, and the chip fixing portion. The sensor chip is fixed to the pressure sensor, and the pressure introduction port fixed to the circuit board and the electrode formed on the sensor chip and the electrode formed on the circuit board are electrically connected by wire bonding. And pressure sensor. 2. A pressure sensor for detecting pressure by a piezoresistive effect, comprising: a circuit board having a hole or notch; and a zero point adjusting circuit or a span adjusting circuit on the circuit board. The chip fixing portion is provided at a position corresponding to the cutout portion, the sensor chip is fixed to the chip fixing portion, and the pressure introducing port is fixed to the circuit board, the electrode formed on the sensor chip and the circuit board. A pressure sensor characterized in that the formed electrode is electrically connected by wire bonding. 3. A pressure sensor for detecting pressure by a piezoresistive effect, comprising a circuit board having holes or notches, and a zero point adjusting circuit or span adjusting circuit and a temperature compensating circuit of a sensor chip on the circuit board, A chip fixing portion is provided at a position corresponding to a hole or a cutout portion of the circuit board, a sensor chip is fixed to the chip fixing portion, and a pressure introduction port fixed to the circuit board and formed on the sensor chip. The pressure sensor is characterized in that the electrode and the electrode formed on the circuit board are electrically connected by wire bonding. 4. A pressure sensor for detecting pressure by a piezoresistive effect, comprising a circuit board having holes or notches, and a zero point adjusting circuit or span adjusting circuit and a temperature compensating circuit for a sensor chip on the circuit board, In addition, a large number of electric circuits are formed on the circuit board, circuit selection means for variously selecting the electric circuits according to the application is provided, and a chip fixing portion is provided at a position corresponding to a hole or a cutout of the circuit board. , A sensor chip is fixed to the chip fixing portion, and a pressure introduction port fixed to the circuit board is electrically connected to an electrode formed on the sensor chip and an electrode formed on the circuit board by wire bonding. A pressure sensor characterized in that 5. A pressure sensor for detecting pressure by a piezoresistive effect, comprising a circuit board having holes or notches, a zero point adjusting circuit or span adjusting circuit, and a temperature compensating circuit of a sensor chip on the circuit board, In addition, a large number of electric circuits are formed on the circuit board, and a circuit selection unit for selecting various electric circuits by laser cutting the circuit selection pattern formed on the circuit board according to the application is provided. A chip fixing portion is provided at a position corresponding to a hole or a cutout portion of a substrate, a sensor chip is fixed to the chip fixing portion, a pressure introducing port fixed to the circuit board, and an electrode formed on the sensor chip. The electrodes formed on the circuit board are electrically connected by wire bonding to cover the sensor chip and block the external light. A pressure sensor characterized in that a cover is provided in a hole or a cutout of the circuit board. 6. A pressure sensor for detecting pressure by a piezoresistive effect, comprising a circuit board having holes or notches, and a zero point adjusting circuit or span adjusting circuit and a temperature compensating circuit of a sensor chip on the circuit board, In addition, a large number of electric circuits are formed on the circuit board, and a circuit selection unit for selecting various electric circuits by laser cutting the circuit selection pattern formed on the circuit board according to the application is provided. A chip fixing portion is provided at a position corresponding to a hole or a cutout portion of a substrate, a sensor chip is fixed to the chip fixing portion, a pressure introducing port fixed to the circuit board, and an electrode formed on the sensor chip. The electrodes formed on the circuit board are electrically connected by wire bonding to cover the sensor chip and block the external light. A pressure sensor, wherein a cover is provided in a hole or notch in the circuit board, and the circuit board and the pressure introducing port are fixed by caulking and welding a fixing pin provided in the pressure introducing port. .