JP2984095B2 - Gas sensor manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a gas sensor, and more particularly, to a method for manufacturing a gas sensor which can be mass- produced.
It is about the law .

[0002]

2. Description of the Related Art Generally, gas sensors as shown in FIGS. 13 and 14 are known as gas sensors used for detecting or quantifying a specific combustible gas contained in an atmospheric gas. . That is, in this gas sensor, as shown in FIG. 14, a detection element 43 and a temperature compensation element 44 having a temperature coefficient close to the temperature coefficient of the detection element 43 for performing temperature compensation are incorporated in a bridge circuit. . As shown in FIG. 13, the detection element 43 is a spherical alumina carrier 41 holding a catalyst 42.
And the embedded platinum wire 40 buried in the alumina carrier 41 and buried.

When the combustible gas acts on and reacts with the catalyst 42 held on the alumina carrier 41, the temperature of the platinum wire 40 rises. In addition, since the electrical resistance of the platinum wire 40 changes due to a change in temperature, the detection or quantification of the flammable gas can be performed by measuring the change in the electrical resistance.

However, since the diameter of the platinum wire 40 is about 40 μm and the diameter of the alumina carrier 41 is about 0.9 mm, which is very small, mass production is difficult. Has a problem that it is difficult to manufacture the temperature compensating element 44 having a temperature coefficient close to the above temperature coefficient.

The present invention solves the above-mentioned problems of the prior art, which enables mass production of the detecting element and the temperature compensating element, and has a temperature coefficient close to the temperature coefficient of the detecting element. It is an object of the present invention to provide a method for manufacturing a gas sensor in which the manufacturing of a compensating element is facilitated.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for manufacturing a single ceramic substrate by using a plurality of identical areas.
And a platinum thin film pattern and wiring in each area
Form a platinum thin-film electrode consisting of terminals
A ceramic member is placed above the gold thin film pattern.
Sintered and masked on half of the ceramic substrate
Temperature compensating element assemblage
Coating a platinum group member on top of
And the ceramic substrate is cut into each
The temperature compensation element from the temperature compensation element assembly,
Detecting elements are respectively formed from the detecting element assembly, and
Select a pair of temperature compensation element and detection element with similar degree coefficients
In this case, a gas sensor is formed .

[0007]

According to the present invention, the above means are adopted.
The detection element and the temperature compensation element can be mass-produced.
The detecting element and the temperature compensating element can be manufactured using a single ceramic substrate, and the detecting element and the temperature compensating element having close temperature coefficients can be easily manufactured.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in the drawings will be described below. FIG. 1 shows the production of a gas sensor according to the present invention.
One embodiment of a gas sensor manufactured by the method is shown. This gas sensor 1 has a detection element 3
And the temperature compensating element 4 is arranged to face, so as to cover the both elements 3 and 4, explosion-proof mesh 16 is provided in an upper portion of the casing 2 and. And the detection element 3
The temperature compensating element 4 is connected to a bridge circuit as shown in FIG.

As shown in FIG. 3, the detecting element 3 is formed by forming a platinum thin film electrode 8 comprising a platinum thin film pattern portion 6 and a wiring terminal portion 7 on a ceramic substrate 5 by a sputtering method or a vapor deposition method. A ceramic-based member 9 made of alumina, silica-alumina, or the like is printed and sintered on the upper portion of the thin-film pattern portion 6, and a platinum-group member 10 made of platinum-group Pt, Pd, Rh, or the like is placed on the ceramic-based member 9 It is coated by a sputtering method or a vapor deposition method.

As shown in FIG. 4, the temperature compensating element 4 has a platinum thin film electrode 14 comprising a platinum thin film pattern portion 12 and a wiring terminal portion 13 formed on a ceramic substrate 11 by a sputtering method or a vapor deposition method. A ceramic member 15 made of alumina, silica-alumina, or the like is printed on the platinum thin film pattern portion 12 and sintered.

In the gas sensor 1 constructed as described above, the combustible gas reacts with the platinum group member 10 disposed above the platinum thin film electrode 8 of the detection element 3 via the ceramic member 9. Then, the temperature of the platinum thin film pattern portion 6 of the platinum thin film electrode 8 is increased. When the temperature of the platinum thin film pattern portion 6 rises, the electrical resistance of the platinum thin film electrode 8 changes. By measuring the amount of change, the flammable gas can be detected or quantified.

Further, since the detecting element 3 and the temperature compensating element 4 are configured as described above, the detecting element 3
In addition, mass production of the temperature compensating element 4 becomes easy, and by manufacturing the detecting element 3 and the temperature compensating element 4 from one ceramic substrate, it becomes easy to make the temperature coefficients uniform.

FIGS. 5 to 10 show an embodiment of a method of manufacturing a gas sensor according to the present invention, and FIGS.
1 shows a detecting element and a temperature compensating element manufactured by the method for manufacturing a gas sensor according to the present invention.

In this method of manufacturing a gas sensor, first, as shown in FIG. 5, one ceramic substrate 21 is divided into a plurality of identical regions, and each region of the ceramic substrate 21 is divided into a plurality of regions as shown in FIG.
As shown in FIG. 5, a platinum thin film electrode 24 composed of a platinum thin film pattern portion 22 and a wiring terminal portion 23 is formed by a sputtering method or a vapor deposition method.

Next, masking is applied to the wiring terminal portions 23 of the platinum thin film electrodes 24 on the ceramic substrate 21 on which the platinum thin film electrodes 24 are formed, as shown in FIG.
A ceramic member 25 made of alumina, silica-alumina or the like is printed and sintered on the platinum thin film pattern portion 22 of each platinum thin film electrode 24.

Further, half of the ceramic substrate 21 on which the ceramic-based member 25 is sintered is masked on the platinum thin-film electrode 24, and the masked portion is used as a temperature compensation element assembly 28 to perform masking. A platinum group member 26 made of platinum group Pt, Pd, Rh, or the like is coated on the other half of the ceramic-based member 25 by a sputtering method or a vapor deposition method to form a detection element assembly 27, as shown in FIG. As shown in FIG. 9, a ceramic substrate 21 is formed in which half is the temperature compensation element assembly 28 and the other half is the detection element assembly 27.

The ceramic substrate 21 having the temperature compensating element assemblage half and the other half as the detecting element assemblage 27 is placed on the upper part of the heater 31 as shown in FIG. The measuring terminals 29 are brought into contact with the wiring terminals 23 of the platinum thin film electrodes 24 in the respective regions from above the ceramic substrate 21 so that the platinum thin film electrodes 24 face upward.
Are connected together by a connector 30 and connected to a multimeter so that the electric resistance value of the platinum thin film electrode 24 can be measured. Then, the temperature coefficient of each platinum thin-film electrode 24 in each region is measured by changing the temperature of the heater section 31.

Next, the ceramic substrate 21 in which one half is the temperature compensation element assembly part 28 and the other half is the detection element assembly part 27 is cut into each region. A temperature compensating element 34 shown in FIG. 11 is formed, and the detecting element 33 shown in FIG.
To form

[0019] Then, a combination of the detecting element 33 and the temperature compensating element 34 close temperature coefficient, write set to the bridge circuit no
As a result, the gas sensor 1 having the above-described configuration is manufactured.
Is done.

In the manufacturing method of the gas sensor configured as described above, the detecting element 33 and the temperature compensating element 34
Can be mass-produced. In addition, the detecting element 33 and the temperature compensating element 34 can be manufactured simultaneously from one ceramic substrate, and the detecting elements 3 having similar temperature coefficients can be manufactured.
3 and the temperature compensation element 34 can be easily manufactured.

[0021]

According to the present invention, as described above, the detecting element and the temperature compensating element can be mass-produced. In addition, the detection element and the temperature compensation element can be manufactured simultaneously from one ceramic substrate,
This has an excellent effect that the detecting element and the temperature compensating element having close temperature coefficients can be easily manufactured.

[Brief description of the drawings]

FIG. 1 shows a method for manufacturing a gas sensor according to the present invention.
It is the schematic which shows the Example of the manufactured gas sensor.

FIG. 2 is a schematic diagram showing a bridge circuit of the one shown in FIG.

FIG. 3 is a schematic diagram showing a detection element of the one shown in FIG.

FIG. 4 is a schematic diagram showing a temperature compensating element of FIG.

FIG. 5 is a schematic view showing a state in which a platinum thin-film electrode is provided in each region of a ceramic substrate in the embodiment of the gas sensor manufacturing method according to the present invention.

FIG. 6 is a partially enlarged schematic view of FIG. 5;

FIG. 7 is a partially enlarged schematic view showing a state in which a ceramic-based member is provided on a platinum thin-film electrode provided in each region of a ceramic substrate in the embodiment of the gas sensor manufacturing method according to the present invention.

FIG. 8 is a schematic diagram showing a detection element assembly and a temperature compensation element assembly of a ceramic substrate in an embodiment of the gas sensor manufacturing method according to the present invention.

FIG. 9 is a partially enlarged schematic view showing a boundary portion between a detection element assembly and a temperature compensation element assembly of a ceramic substrate in the embodiment of the gas sensor manufacturing method according to the present invention.

FIG. 10 is a schematic diagram showing an apparatus for measuring a temperature coefficient between a detection element assembly and a temperature compensation element assembly of a ceramic substrate in an embodiment of the gas sensor manufacturing method according to the present invention.

FIG. 11 is a schematic view showing a detection element manufactured in an embodiment of the method for manufacturing a gas sensor according to the present invention.

FIG. 12 is a schematic view showing a temperature compensation element manufactured in an embodiment of the method for manufacturing a gas sensor according to the present invention.

FIG. 13 is a schematic diagram showing a detection element in a conventional gas sensor.

FIG. 14 is a schematic diagram showing a bridge circuit in a conventional gas sensor. DESCRIPTION OF SYMBOLS 1 ... Gas sensor 2 ... Case 3, 33, 43 ... Detection element 4, 34, 44 ... Temperature compensation element 5, 11, 21 ... Ceramic substrate 6, 12, 22 ... Platinum thin film pattern part 7, 13 , 23 wiring terminal part 8, 14, 24 ... platinum thin film electrode 9, 15, 25 ... ceramic member 10, 26 ... platinum group member 16 ... explosion-proof mesh 27 ... detection element collecting part 28 ... Temperature compensating element assembly part 29 Measurement terminal 30 Connector 31 Heater part 40 Platinum wire 41 Alumina carrier 42 Catalyst

Claims (1)

(57) [Claims] 1. A single ceramic substrate is divided into a plurality of same regions.
And the platinum thin film pattern and wiring
Forming a platinum thin film electrode comprising a
A ceramic member is placed on top of the thin film pattern and fired.
And masking half of the ceramic substrate
Temperature compensating element assembly, and the other half of each ceramic
Detector with platinum group member coated on top of system member
As an assembly, cut the ceramic substrate for each region
The temperature compensating element is arranged at a position
Detecting elements are formed from the detecting element assembly,
Select a pair of temperature compensation element and detection element whose coefficients are similar.
A gas sensor characterized by forming
Production method.