JPH04370754A - Gas sensor and manufacture thereof - Google Patents

Abstract

PURPOSE:To enable massproducibility to be improved. CONSTITUTION:One ceramic substrate 5 (11) is sectioned into a plurality of same regions, a platinum thin-film electrode consisting of a platinum thin-film pattern 6 (12) and a wiring terminal portion 7 (13) is formed within each region, and a ceramic member 9 (15) is placed on an upper portion of the platinum thin-film pattern portion 6 (12) before sintering. Masking is performed to half of a ceramic substrate for obtaining a temperature compensation element assembly portion 28, a platinum member 26 is coated on an upper portion of the remaining half ceramic member for obtaining a detection element assembly portion 27, and then the ceramic substrate is cut for each region for forming a temperature-compensation element 4 by a temperature-compensation element assembly portion and a detection element 3 by the detection element assembly portion, respectively. A pair of the temperature-compensation element 4 and the detection element 3 with a close temperature coefficient are selected for forming a gas sensor.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas sensor and a method of manufacturing the same, and more particularly to a gas sensor and a method of manufacturing the same that can be mass-produced.

0002

[Prior Art and Problems to be Solved] Gas sensors shown in FIGS. 13 and 14 are generally known as gas sensors used to detect or quantify specific combustible gases contained in atmospheric gas. . That is, as shown in FIG. 14, this gas sensor includes 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 temperature compensation, which are incorporated into a bridge circuit. . As shown in FIG. 13, the detection element 43 consists of a spherical alumina carrier 41 that holds the catalyst 42, and a platinum wire 40 that is buried in the alumina carrier 41 and has a coiled portion. There is.

[0003] When the flammable gas acts on the catalyst 42 held on the alumina carrier 41 and reacts, the temperature of the platinum wire 40 rises. Furthermore, since the electrical resistance of the platinum wire 40 changes with temperature changes, combustible gas can be detected or quantified by measuring the change in electrical resistance.

However, the detection element 43 is very small, with the platinum wire 40 having a diameter of about 40 μm and the alumina carrier 41 having a diameter of about 0.9 mm, making mass production difficult. The problem is that it is difficult to manufacture a temperature compensation element 44 having a temperature coefficient close to that of .

The present invention solves the problems of the conventional devices as described above, and makes it possible to mass produce detection elements and temperature compensation elements. It is an object of the present invention to provide a gas sensor in which the compensating element can be easily manufactured and a method for manufacturing the same.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a gas sensor including a detection element and a temperature compensation element as a pair, wherein the detection element is formed of a platinum metal plate on the top of a ceramic substrate. A platinum thin film electrode consisting of a thin film pattern part and a wiring terminal part is formed, a ceramic member is placed and sintered on the top of the platinum thin film pattern part, and the top of the ceramic member is coated with a platinum group member. The temperature compensating element is obtained by forming a platinum thin film electrode consisting of a platinum thin film pattern part and a wiring terminal part on the upper part of a ceramic substrate, and sintering the ceramic member arranged on the upper part of the platinum thin film pattern part. and
This method employs a method of detecting combustible gas by measuring changes in the electrical resistance value of the detection element. Also, 1
A sheet of ceramic substrate is divided into a plurality of identical regions, a platinum thin film electrode consisting of a platinum thin film pattern portion and a wiring terminal portion is formed in each region, and a ceramic member is disposed above the platinum thin film pattern portion. The ceramic substrate is sintered, and half of the ceramic substrate is masked to form a temperature compensation element assembly part, and the remaining half of the ceramic member is coated with a platinum group member to form a detection element assembly part, and the ceramic substrate is used for each region. A temperature compensating element is formed from the temperature compensating element gathering part, and a detecting element is formed from the detecting element gathering part, respectively, and a pair of a temperature compensating element and a detecting element having approximate temperature coefficients is selected. This method adopts the method of forming a gas sensor.

[0007]

[Operation] By adopting the above-mentioned means, this invention
Detection elements and temperature compensation elements can be mass-produced, and 1
The detection element and the temperature compensation element can be manufactured using a single ceramic substrate, and the detection element and the temperature compensation element having similar temperature coefficients can be easily manufactured.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention shown in the drawings will be described below. FIG. 1 shows an embodiment of a gas sensor according to the present invention, in which a detection element 3 and a temperature compensation element 4 are disposed facing each other on the upper surface of a case 2, and both of the elements 3 and 4 are covered. In this way, an explosion-proof mesh 16 is provided on the upper part of the case 2. The detection element 3 and temperature compensation element 4 are connected to a bridge circuit as shown in FIG.

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

Further, as shown in FIG. 4, the temperature compensating element 4 is formed by forming a platinum thin film electrode 14 consisting of a platinum thin film pattern part 12 and a wiring terminal part 13 on the top of a ceramic substrate 11 by sputtering or vapor deposition. A ceramic member 15 made of alumina, silica alumina, etc. is printed on the platinum thin film pattern portion 12 and sintered.

In the gas sensor 1 constructed as described above, the combustible gas acts and reacts with the platinum group member 10 disposed on 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 section 6 rises, the electrical resistance of the platinum thin film electrode 8 changes, and by measuring the amount of change, the combustible gas can be detected or quantified.

Furthermore, by configuring the detection element 3 and the temperature compensation element 4 as described above, the detection element 3
And mass production of the temperature compensation element 4 becomes easy, and by manufacturing the detection element 3 and the temperature compensation element 4 from one ceramic substrate, it becomes easy to make the temperature coefficients the same.

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

The manufacturing method of this gas sensor is as follows: First, one ceramic substrate 21 is divided into a plurality of identical regions as shown in FIG.
As shown in FIG. 2, a platinum thin film electrode 24 consisting of a platinum thin film pattern portion 22 and a wiring terminal portion 23 is formed by a sputtering method, a vapor deposition method, or the like.

Next, the wiring terminal portion 23 of each platinum thin film electrode 24 of the ceramic substrate 21 on which the platinum thin film electrode 24 is formed is masked, and as shown in FIG.
A ceramic member 25 made of alumina, silica alumina, etc. is printed on the platinum thin film pattern portion 22 of each of the platinum thin film electrodes 24 and sintered.

Furthermore, half of the ceramic substrate 21 on which the ceramic member 25 is sintered on top of the platinum thin film electrode 24 is masked, and the masked part is used as the temperature compensating element gathering part 28, and the masking is performed. A platinum group member 26 made of a platinum group member such as Pt, Pd, Rh, etc. is coated on the top of the remaining half of the ceramic member 25 by sputtering or vapor deposition to form a detection element gathering portion 27, as shown in FIG. As shown in FIG. 9, a ceramic substrate 21 is formed, one half of which is a temperature compensation element assembly section 28 and the other half of which is a detection element assembly section 27.

As shown in FIG. 10, the ceramic substrate 21 having half the temperature compensation element assembly section 28 and the other half the detection element assembly section 27 configured as described above is attached to the upper part of the heater section 31. The platinum thin film electrodes 24 are arranged with the platinum thin film electrodes 24 facing upward, and the measurement terminals 29 are brought into contact with the wiring terminal portions 23 of the platinum thin film electrodes 24 in each region from above the ceramic substrate 21.
The wirings are gathered together with a connector 30 and connected to a multimeter so that the electrical resistance value of the platinum thin film electrode 24 can be measured. Then, the temperature of the heater section 31 is changed and the temperature coefficient of each platinum thin film electrode 24 in each region is measured.

Next, the ceramic substrate 21, half of which is the temperature compensating element gathering part 28 and the other half being the detecting element gathering part 27, is cut into each region, and from the temperature compensating element gathering part 28, as shown in FIG. The temperature compensating element 34 shown in FIG. 11 is formed, and the sensing element 33 shown in FIG.

Then, the detection element 33 and the temperature compensation element 34 having similar temperature coefficients are combined and assembled into a bridge circuit to manufacture a gas sensor.

In the method for manufacturing the gas sensor configured as described above, the detection element 33 and the temperature compensation element 34 are
can be mass-produced. In addition, the detection element 33 and the temperature compensation element 34 can be manufactured simultaneously from one ceramic substrate, and the detection element 33 and the temperature compensation element 34 have similar temperature coefficients.
3 and temperature compensation element 34 can be easily manufactured.

[0021]

According to the present invention configured as described above, detection elements and temperature compensation elements can be mass-produced. In addition, it is possible to simultaneously manufacture a detection element and a temperature compensation element from one ceramic substrate, and
This has the excellent effect that detecting elements and temperature compensating elements with similar temperature coefficients can be easily manufactured.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of a gas sensor according to the present invention.

FIG. 2 is a schematic diagram showing a bridge circuit in an embodiment of the gas sensor according to the invention.

FIG. 3 is a schematic diagram showing a detection element in an embodiment of the gas sensor according to the present invention.

FIG. 4 is a schematic diagram showing a temperature compensation element in an embodiment of the gas sensor according to the invention.

FIG. 5 is a schematic diagram showing a state in which platinum thin film electrodes are provided in each region of a ceramic substrate in an embodiment of the method for manufacturing a gas sensor according to the present invention.

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

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

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

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

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

FIG. 11 is a schematic diagram 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 diagram 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. 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 portion 7, 13 , 23
... Wiring terminal parts 8, 14, 24 ... Platinum thin film electrodes 9, 15, 25 ... Ceramic members 10, 26 ... Platinum group members 16 ... Explosion-proof mesh 27 ... Detection element assembly section 28 ... Temperature compensation Element gathering section 29...Measuring terminal 30...Connector 31...Heater section 40...Platinum wire 41...Alumina carrier 42...Catalyst

Claims (2)

[Claims] [Claim 1] Detection element (3) and temperature compensation element (4)
is a pair of gas sensors, wherein the detection element (
3) forms a platinum thin film electrode (8) consisting of a platinum thin film pattern part (6) and a wiring terminal part (7) on the top of the ceramic substrate (5);
A ceramic member (9) is disposed and sintered on the upper part of the temperature compensating element (4), and the upper part of the ceramic member (9) is coated with a platinum group member (10).
A platinum thin film electrode (14) consisting of a platinum thin film pattern part (12) and a wiring terminal part (13) is formed on the top of a ceramic substrate (11), and the platinum thin film pattern part (
A ceramic member (15) is arranged and sintered on the upper part of the sensor 12), and the combustible gas is detected by measuring the change in the electrical resistance value of the detection element (3). gas sensor. 2. One ceramic substrate (21) is divided into a plurality of identical regions, and a platinum thin film pattern portion (
A platinum thin film electrode (24) consisting of a wiring terminal part (22) and a wiring terminal part (23) is formed, and each of the platinum thin film pattern parts (22) and a wiring terminal part (23) are formed.
22), a ceramic member (25) is disposed on top of the ceramic substrate (22) and sintered, half of the ceramic substrate (21) is masked to form a temperature compensation element assembly part (28), and the remaining half of each of the ceramic members A platinum group member (
26) to form a detection element assembly part (27), and cut the ceramic substrate (21) into each region to form a temperature compensation element (34) from the temperature compensation element assembly part (28).
), and detecting elements (33) are respectively formed from the detecting element assembly part (27), and a pair of temperature compensating element (34) and detecting element (33) with approximate temperature coefficients is selected to form a gas sensor. A method of manufacturing a gas sensor, characterized by forming a gas sensor.