JPH06102222A - Odor sensor - Google Patents

Abstract

PURPOSE:To obtain an odor sensor which is easy to manufacture and loses less heat at a heater. CONSTITUTION:A sensor part S is constituted of an element substrate 2, a sensor element 3 on the element substrate 2, a heating part 10 for heating the sensor element and two or more electrodes 4 on the element substrate 2. The sensor part S is supported in the air and fixed by conductive wires 7, 7' within an opening part 6 of a base 5. Moreover, the base 5 is arranged in touch with lead pins 8a, 8b and secured by a conductive member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an odor sensor, and more particularly to an odor sensor which is easy to manufacture and has a small heat loss of a heater.

[0002]

2. Description of the Related Art In recent years, as a method for early detection of a fire, a method of detecting a burning odor generated before smoke in a fire by an odor sensor has attracted attention. In a conventional odor sensor, as shown in FIG. 4, a plurality of terminals 14 (lead pins) are provided at intervals on a circuit board 13 such as a glass board on which a main electric circuit is mounted. The lead wire 15 for the sensor electrode 4 and the heater electrode (not shown) was spot-welded and attached to the portion. Further, in the sensor section S in which the sensor element 3 (for example, stannic oxide) and the heating section (heater) are provided on the element substrate made of alumina, the sensor element 3
A heater that was printed and fired was provided on the opposite surface through the element substrate, and the heater was heated to 200 to 500 ° C. or higher for the sensor element 3 to sense and detect odor. The purpose of this heating is (1) to improve the sensitivity to the odor and gas for the purpose of detection by the sensor element; (2) to make the response speed sensitive; (3) to avoid the influence of water vapor in the atmosphere. That is.

[0003]

However, in such a conventional odor sensor, the lead wires 15 are attached to the element substrate in advance, and the lead wires 15 are carefully arranged in the nail of the terminal 14. It was necessary to perform spot welding in the unstable state of hanging in the air, which was very troublesome. Further, it is difficult to drop the element substrate between the terminals 14 and suspend it in the air when welding the lead wires 15. Further, the lead wire 15 is made thin in order to reduce heat radiation to the terminal 14, and therefore, the lead wire 15 is easily broken due to the weight of the substrate or applied vibration, which is disadvantageous in terms of strength. The present invention solves the above-mentioned conventional problems, does not require time-consuming spot welding, is easy to manufacture, and is unlikely to cause breakage of the lead wire, and further, the sensor portion and other portions on the substrate It is an object of the present invention to provide an odor sensor with less heat loss in a heater that is efficiently thermally insulated.

[0004]

As a result of earnest studies, the present inventors were able to solve the above-mentioned conventional problems. That is, according to the present invention, an element substrate, a sensor element on the element substrate, a heating unit for heating the sensor element, and a sensor unit including two or more electrodes provided on the element substrate are provided on a base. The odor sensor is characterized in that the pedestal is suspended and fixed by an electrically conductive wire in the opening, and the base is abutted on a lead pin and fixed by a conductive member.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is an odor sensor of the present invention, 2
Is an element substrate made of alumina or the like, 3 is a sensor element, 4 is a sensor electrode, 5 is a base, 6 is an opening of the base 5, 7 and 7'are conductive wires (for example, gold wires), 8a and 8b. Are lead pins for sensor output and lead pins for heater, respectively, which support the base 5 and energize the sensor output and the heater. Reference numerals 9 and 9 ′ are conductor patterns fired by screen-printing gold pastes for sensors and heaters, respectively.
Reference numeral 11 denotes an abutment arrangement portion where the base 5 and the lead pins 8a and 8b abut. As shown in FIG. 2, on the opposite surface of the sensor element 3 through the element substrate 2, a heating portion, for example, a heater 10 made of ruthenium oxide formed by a paste and a heater electrode 4 ′ are provided. It constitutes part S. The conductive wires 7 and 7 ′ are connected to the conductor patterns 9 and 9 ′ printed on the base 5.

As shown in FIG. 1, in the sensor unit S, the sensor electrode 4'on the front side is connected to the base 5 by the conductive wire 7 in the opening 6 of the base 5, and further the conductive property is obtained. The base 5 and the heater electrode 4 on the back side of the sensor section S are connected by a wire 7 '. Here, the conductive wires 7 and 7 ′ are combined in different directions and connected to the element substrate 2. Therefore, the sensor unit S is a conductive wire 7,
It is well fixed by 7 '. By suspending and fixing the sensor unit S in the opening 6 of the base 5 as described above, heat emitted from the heater 10 is not transferred to the base 5 and the lead pins 8a and 8b,
The adverse effect of heat on other circuits is prevented.
In the odor sensor of the present invention, the element substrate 2 and the base 5
It is preferable that the conductive wires 7 and 7 ′ do not rub against the element substrate 2 and the durability is improved when the thicknesses of the two are the same. Further, bonding (welding of the wires 7 and 7 ') is also easy. The size of the opening 6 is not particularly limited as long as the sensor S can be housed therein, the heat of the sensor element 3 is retained, and the heat is not easily transferred to the base 5. In the present invention, the shape of the opening 6 as shown in FIG. 1, the number of electrically conductive wires 7 and 7 ′, and the connecting direction are not particularly limited and can be freely selected.

In the odor sensor 1 of the present invention, the base 5 as described above is further provided with an abutting arrangement portion 1 for the lead pins 8a and 8b.
1 is abuttingly arranged and fixed. As a result, it is not necessary to hang the element substrate 2 in the air, which is required in the conventional technique, to perform the spot welding of the lead wire, which is troublesome, and the manufacturing is facilitated. The wiring provided on the base 5 and the lead pins 8a and 8b can be connected by a conductive member, such as welding (bonding) or soldering. Since the connection can be made by soldering as described above, it is not necessary to perform spot welding. If the conductor patterns 9 and 9 ′ are printed not only on the front surface and the back surface of the base 5 but also on the side surfaces, they can be easily fixed by soldering. In the present invention, the conventional lead pins 8a and 8b can be used, but it is preferable to use a nail pin having a thick tip as shown in FIG. 1 because the element substrate 2 can be easily arranged. The contact placement portion 11 of the lead pins 8a and 8b in FIG.
If it is / 4 or less, heat dissipation from the base 5 is reduced, which is preferable.

As a mode different from the above, as shown in FIG. 3, by providing a stepped contact arrangement portion 12 above the lead pins 8a and 8b, the base 5 can be further fixed well. It is possible and preferable. In this case, the size, shape, etc. of the stepped contact placement portion 12 are not particularly limited, and can be appropriately determined depending on the shape of the base 5.

In this embodiment, the heater is provided on the back surface of the sensor element 3, but the sensor element 3 may be provided on the upper side of the heater via an insulating layer. Further, although this structure is shown for the case of one element, for example, it is a structure of two or more elements in which three or more electrodes are provided and the elements of the sensor element 3 having different components are arranged in parallel. Well, by doing so, the odor can be better identified, and false alarms can be eliminated when determining a fire.

[0010]

According to the odor sensor of the present invention, as described in the above embodiment, the sensor portion is stably suspended and fixed well, so that the heat generated in the sensor element is held without being transmitted through the element substrate. Therefore, the power consumption can be further reduced without adversely affecting other circuits. Further, since the element substrate is placed on the lead pin without being suspended by the lead wire, it is easy to manufacture, and the lead wire is less likely to be broken due to the weight of the substrate or applied vibration.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an odor sensor of the present invention.

FIG. 2 is a cross-sectional view showing the sensor unit of FIG.

FIG. 3 is a perspective view showing another embodiment of the odor sensor of the present invention.

FIG. 4 is a perspective view showing an outline of a conventional odor sensor.

[Explanation of symbols]

 1 Odor Sensor 2 Element Substrate 3 Sensor Element 4 Sensor Electrode 5 Base 6 Opening 7,7 'Conductive Wire 8a Sensor Lead Pin 8b Heater Lead Pin 9 Conductor Pattern 10 Heating Section 11 Contact Arrangement Section 12 Step Form Contact placement section S sensor section

Claims (1)

[Claims] 1. An element substrate, a sensor element on the element substrate,
A heating section for heating the sensor element and a sensor section including two or more electrodes provided on the element substrate are suspended and fixed by an electrically conductive wire in an opening provided in a base, and An odor sensor, characterized in that the base is disposed in contact with a lead pin and is fixed by a conductive member.