JP2001059790A - Gage for pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gage for a pressure sensor which does not require any correction to the balance among electric resistance values of a Wheatstone bridge even if there are relative varieties in the locations of formation of resistor pattern films and electrode pattern films. SOLUTION: A gage for a pressure sensor is formed by bringing four resistor pattern films 2a-2d into adhesion onto a diaphragm 1 in such a way as to form a Wheatstone bridge and electrode pattern films 3a-3d for external connection into adhesion in such a way as to cover the connection parts of the resistor pattern films 2a-2d. The electrode pattern films 3a-3d located at both ends of the resistor pattern films 2a-2d are each provided with sides parallel with each other to the sides facing each other, and the resistor pattern films 2a-2d with the same width at their both end parts are connected to the sides. Even if there are varieties in the locations of formation of the resistor pattern films 2a-2d and electrode pattern films 3a-3d, as the lengths and areas of the resistor pattern films 2a-2d each exposed between the electrode pattern films 3a-3d are constant at all times, the balance among electric resistance values of the Wheatstone bridge does not collapse.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gauge for a pressure sensor for measuring pressure by converting deflection of a diaphragm into an electric signal.

[0002]

2. Description of the Related Art Conventionally, as a pressure sensor gauge, a Wheatstone bridge is formed on a main surface of a disk-shaped diaphragm 21 made of an electrically insulating material such as zirconia ceramics as shown in a plan view of FIG. Like 4
The resistive pattern films 22a, 22b, 22c, and 22d are attached by a thin film method, and each of the resistive pattern films 22a
It is known that electrode pattern films 23a, 23b, 23c, and 23d for external connection are similarly adhered by a thin film method so as to cover a connection portion between 22b, 22c, and 22d.

In this pressure sensor gauge, when pressure is applied to one main surface of the diaphragm 21, the diaphragm 21 bends in accordance with the pressure, thereby causing the resistor pattern films 22a, 22b, 22c, and 22d to move. Distortion occurs and the electrical resistance of each of the resistor pattern films 22a, 22b, 22c, and 22d changes. Then, such resistor pattern films 22a and 22
b, 22c, 22d, the change in the electric resistance value
The pressure is detected by measuring via a, 23b, 23c and 23d.

In this conventional pressure sensor gauge, each electrode pattern film 23a, 23b, 23c, 23d
Each had a square shape, and were arranged so that the four sides were parallel and perpendicular to each other. Further, each of the resistor pattern films 22a, 22b, 22c, and 22d were connected to mutually perpendicular sides of the electrode pattern films 23a, 23b, 23c, and 23d located at both ends thereof, facing each other.

The conventional pressure sensor gauge includes a resistor pattern film 22a, 22a on the main surface of the diaphragm 11.
After b.22c.22d is formed in a predetermined pattern, the electrode pattern films 23a.23b.23c.23d are formed thereon in a predetermined pattern.

[0006]

However, in this conventional pressure sensor gauge, a resistor pattern film is used.
22a / 22b / 22c / 22d and electrode pattern films 23a / 23b /
Since 23c and 23d are formed separately, the resistor pattern films 22a, 22b, 22c and 22d and the electrode pattern films 23a and 23d are formed separately.
Relative variations occur due to manufacturing errors in the formation positions of 23b, 23c and 23d.

In a conventional pressure sensor gauge,
Each of the resistor pattern films 22a, 22b, 22c, and 22d has electrode pattern films 23a, 23b, 23c,
Because they are connected to mutually perpendicular sides of the opposing sides of 23d, the electrode pattern films 23a, 23b, 23c, and 23d are originally formed as shown by a two-dot chain line, for example, as shown in a plan view in FIG. X to the right of the figure
However, when the resistor pattern film 22a is shifted upward by y, the exposed length of the resistor pattern film 22a becomes longer by x and y, and the exposed length of the resistor pattern film 22b becomes longer by x. Together with the length of the resistor pattern film 22
The exposed length of c becomes shorter by x and y, and the exposed length of the resistor pattern film 22d becomes shorter by x and longer by y. As a result, the electric resistance of the Wheatstone bridge is reduced. The resistance value balance is broken from the original balance.

Therefore, in the conventional pressure sensor gauge, it is necessary to correct the electric resistance value balance of the Wheatstone bridge for each individual pressure sensor gauge, and there is a problem that this correction is complicated. Was.

The present invention has been made in view of the above-described drawbacks of the conventional pressure sensor gauge, and has as its object the relative variation in the formation positions of the resistor pattern film and the electrode pattern film. Another object of the present invention is to provide a gauge for a pressure sensor which does not need to correct the electric resistance value balance of a Wheatstone bridge.

[0010]

According to a pressure sensor gauge of the present invention, four resistor pattern films are attached to a diaphragm so as to form a Wheatstone bridge, and each of the resistor pattern films is connected to each other. A pressure sensor gauge formed by attaching an electrode pattern film for external connection so as to cover the connection portion of the resistor pattern film, wherein the electrode pattern films located at both ends of each of the resistor pattern films are parallel to each other on opposite sides. And each of the resistor pattern films is connected to these sides at the same width at both ends thereof.

According to the pressure sensor gauge of the present invention, the electrode pattern films located at both ends of each resistor pattern film have sides parallel to each other on opposite sides.
Since each resistor pattern film is connected to these sides at the same width at both ends, there is a relative variation between the formation position of the resistor pattern film and the formation position of the electrode pattern film. Even if this is done, the length and area of the resistor pattern film between the electrode pattern films, that is, the resistance value will not vary.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a plan view showing an embodiment of a pressure sensor gauge according to the present invention, wherein 1 is a diaphragm, 2a, 2b, 2c and 2d are resistor pattern films, 3a
3b, 3c, 3d are electrode pattern films.

The diaphragm 1 is a substantially circular plate made of, for example, zirconia ceramics, and when a pressure is applied to a main surface thereof, a bending according to the pressure is generated.

Such a diaphragm 1 is manufactured by punching a green sheet of zirconia ceramics into a circular shape and firing it at a high temperature.

On one main surface of the diaphragm 1, four resistor pattern films 2a, 2b, 2c and 2d are attached so as to form a Wheatstone bridge.

Resistor pattern films 2a, 2b, 2c, 2d
Is made of, for example, NiCrSi, and is distorted by bending of the diaphragm, so that each electric resistance value changes.

The resistor pattern films 2a and 2b.
2c and 2d are Ni over the entire one main surface of the diaphragm 1.
A thin film of CrSi is deposited by using a thin film forming technique of a sputtering method, and then formed by etching into a predetermined pattern by using a photolithography technique.

The resistor pattern films 2a, 2b, 2c
2d tends to be easily broken in the resistor pattern films 2a, 2b, 2c and 2d when its thickness is less than 50 angstroms, and on the other hand, when it exceeds 50000 angstroms, the NiCrSi film The generated internal stress becomes large and the resistor pattern film 2
a, 2b, 2c, and 2d tend to easily peel. Therefore, the resistor pattern films 2a and 2b
2c and 2d preferably have a thickness in the range of 50 to 50,000 angstroms.

The main surface of the diaphragm 1 covers the connection between the resistor pattern films 2a, 2b, 2c, and 2d so as to cover the electrode pattern films 3a for external connection.
3b, 3c and 3d are attached.

The electrode pattern films 3a, 3b,
3c and 3d are the resistor pattern films 2a, 2b, 2c and 2
The electrode for connecting the Wheatstone bridge formed by d to an external measuring device, for example, a multilayer film of a titanium film, a platinum film, and a gold film. Then, these electrode pattern films 3a, 3b, 3c, 3d are connected to an external measuring device to connect the respective resistor pattern films 2a, 2b, 2c.
The pressure applied to the diaphragm 1 can be detected by measuring the change in the electric resistance value of 2d.

Such electrode pattern films 3a, 3b, 3
c and 3d are the respective electrode pattern films 3a, 3b, 3c and 3d.
A mask having an opening corresponding to the resistor pattern film 2a
2b, 2c and 2d are superimposed on the main surface of the diaphragm 1 and a titanium film, a platinum film and a gold film are sequentially deposited thereon by using a thin film technique such as a sputtering method, so that each resistor is formed. Body pattern films 2a, 2b
It is attached so as to cover the connection portions 2c and 2d.

The electrode pattern films 3a, 3b, 3c,
The titanium film constituting 3d is a metal layer that adheres to the diaphragm 1. If the thickness is less than 100 angstroms, it tends to be difficult to firmly adhere to the diaphragm 1, while if it exceeds 2000 angstroms, Separation tends to occur easily due to internal stress generated in the titanium film during film formation. Therefore, it is preferable that the thickness of the titanium film constituting the electrode pattern films 3a, 3b, 3c, 3d be in the range of 100 to 2,000 angstroms.

The electrode pattern films 3a, 3b, 3c,
The platinum film constituting 3d is a barrier layer for preventing titanium in the titanium film from diffusing into the gold film. If the thickness is less than 500 angstroms, the diffusion of titanium can be sufficiently prevented. Tend to be impossible, while 10
If it exceeds 000 angstroms, peeling tends to occur easily due to internal stress generated in the platinum film during film formation. Therefore, the electrode pattern films 3a, 3b,
The thickness of the platinum film constituting 3c and 3d is 500 to 1000.
It is preferable to keep 0 angstrom.

Further, the electrode pattern films 3a, 3b, 3c
The gold film constituting 3d is composed of the electrode pattern films 3a, 3b.
This is a surface layer for improving the connectivity between 3c and 3d and the outside. If the thickness is less than 1000 angstroms, sufficient connectivity tends not to be obtained.
If it exceeds 000 angstroms, peeling tends to occur easily due to internal stress generated in the gold film during film formation. Therefore, the electrode pattern films 3a, 3b, 3c
-It is preferable that the thickness of the gold film constituting 3d is set to 1,000 to 50,000 angstroms.

In this example, the electrode pattern films 3a, 3b, 3c, 3d for external connection are substantially square, and are arranged such that four sides are parallel and perpendicular to each other.

Each of the resistor pattern films 2a, 2b,
2c and 2d are electrode pattern films 3a located at both ends thereof.
3b, 3c and 3d are connected to the mutually parallel sides on the side facing each other at the same width at both ends.

As described above, each of the resistor pattern films 2a and 2a
b, 2c, 2d are connected to the mutually parallel sides of the electrode pattern films 3a, 3b, 3c, 3d located at both ends on the side facing each other with the same width at both ends, for example, As shown in the plan view of FIG. 2, it is assumed that each of the electrode pattern films 3a, 3b, 3c, and 3d is shifted by x in the right direction of the figure and by y in the upward direction of the figure from the position where it should be formed by the broken line. Also, each of the resistor patterns 2a and 2
The exposed lengths and areas of b, 2c, and 2d decrease at the other end by an amount that increases at one end and are always constant. As a result, the balance of the electric resistance value of the Wheatstone bridge is originally reduced. There's nothing out of balance. Therefore, according to the pressure sensor gauge of the present invention, it is not necessary to correct the electric resistance balance of the Wheatstone bridge for each gauge.

Each resistor pattern film 2a, 2b, 2
c · 2d are the electrode pattern films 3a ·
When both ends are connected with different widths to mutually parallel sides of the sides 3b, 3c, 3d facing each other, the resistor pattern films 2a, 2b, 2c, 2d and the electrode pattern films 3a, 3b, 3d. The increase or decrease in the exposed area of each of the resistor patterns 2a, 2b, 2c and 2d due to the variation in the formation position with respect to 3c and 3d is caused by each of the resistor patterns 2a, 2b and 2c
-The balance of the electric resistance value of the Wheatstone bridge is broken from the original balance without being complemented at both ends of the 2d. Therefore, each of the resistor pattern films 2a, 2b, 2c, 2d has the same width at both ends with respect to the mutually parallel sides of the electrode pattern films 3a, 3b, 3c, 3d located at both ends facing each other. Must be connected by

Thus, according to the pressure sensor gage of the present invention, it is possible to provide a pressure sensor gage which does not need to correct the electric resistance value balance of the Wheatstone bridge in each pressure sensor gage.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention. Such an example is shown below.

FIG. 3 is a plan view showing another example of the embodiment of the present invention. The pressure sensor gauge of this example has four resistor pattern films on the main surface of a substantially disk-shaped diaphragm 11.
12a, 12b, 12c, and 12d are attached so as to form a Wheatstone bridge.
External connection electrode pattern films 13a, 13b, 13c and 13d are attached so as to cover the connection portions between 12a, 12b, 12c and 12d.

In this example, each electrode pattern film 13a
The arrangement of 13b, 13c and 13d is different from the example of the above-described embodiment.

In one example of the above-described embodiment, the electrode pattern films 3a, 3b, 3c, and 3d are parallel to each other at opposite ends of each of the resistor pattern films 2a, 2b, 2c, and 2d. However, in this example, the electrode pattern films 13a, 13b, 13c, and 13d are located at both ends of each of the resistor pattern films 12a, 12b, 12c, and 12d. The objects are arranged such that mutually parallel sides facing each other are directly opposite. In this manner, the electrode pattern films 13a, 13b, 13c, 13d located at both ends of each of the resistor pattern films 12a, 12b, 12c, 12d are arranged so that the mutually parallel sides facing each other are directly facing each other. Is also good.

[0035]

According to the pressure sensor gauge of the present invention,
The electrode pattern films located at both ends of each resistor pattern film have sides parallel to each other on the side facing each other, and each resistor pattern film is connected to these sides at the same width at both ends. Therefore, even if a relative variation occurs between the formation position of the resistor pattern film and the formation position of the electrode pattern film, the length and area of the resistor pattern film between the electrode pattern films, that is, the resistance value There is no variation. Therefore, it is not necessary to correct the resistance balance of the Wheatstone bridge for each gauge.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a pressure sensor gauge according to an embodiment of the present invention.

FIG. 2 is a plan view for explaining displacement of a pattern film in the pressure sensor gauge shown in FIG.

FIG. 3 is a plan view showing another example of the embodiment of the pressure sensor gauge of the present invention.

FIG. 4 is a plan view showing a conventional pressure sensor gauge.

5 is a plan view for explaining displacement of a pattern film of the pressure sensor gauge shown in FIG. 4;

[Explanation of symbols]

 1, 11 ... diaphragm 2a-2d, 12a-12d ... resistor pattern film 3a-3d, 13a-13d ... electrode pattern film

Claims (1)

[Claims] An electrode for external connection is formed by attaching four resistor pattern films so as to form a Wheatstone bridge on a diaphragm and covering a connection portion between the resistor pattern films. A pressure sensor gauge formed by adhering a pattern film, wherein the electrode pattern films located at both ends of each of the resistor pattern films have sides parallel to each other on opposite sides. Wherein each of the resistor pattern films is connected at the same width to both ends thereof.