JPH0252248A - Moisture sensitive element - Google Patents

Abstract

PURPOSE:To assure the secure connection between electrode terminals and lead wires for drawing out to the outside so that highly reliable connection is enabled by crimping an insulating substrate by means of U-shaped clip pieces of the lead wires and fixing the clip pieces on the front and rear surfaces by adhesive agent parts. CONSTITUTION:The approximately U-shaped clip pieces 9a, 9b are provided to the tips of the lead wires 9 for drawing out to the outside connected to the electrode terminals 2a, 5a of a lower electrode 2 and an upper electrode 5 formed on the insulating substrate 1. These U-shaped clip pieces 9a, 9b are inserted to the electrode terminals 2a, 5a by crimping the substrate 1. The contact parts on one side of the terminals 2a, 5a and the clip pieces 9a, 9b are fixed by the conductive adhesive agent part 11. The rear surface of the substrate 1 and the other contact parts of the clip pieces 9a, 9b are secured by the adhesive agent part 12 for fixing, by which the element is constituted. The generation of a contact defect in the connecting parts of the substrate 1 or the lead wires 9 is obviated even if a mechanical stress, oscillation, etc., are exerted to the substrate or the lead wires. The connection which is highly electrically and mechanically reliable is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a humidity sensing element, and particularly to a connection structure for lead wires for external circuit connection.

[Conventional technology]

Figure 4 is a diagram showing the configuration of a conventional moisture-sensitive element.
, ) is a plan view, and FIG.

In the figure, 1 is an insulating substrate made of, for example, alumina, glass, or thermally oxidized silicon plate, 2 is a lower electrode made of, for example, an Au thin film formed on the main surface of this insulating substrate 1, and 2a is the electrode. Terminal 3 is an auxiliary electrode made of, for example, an Au thin film formed on the end of the insulating substrate 1; The humidity sensitive film 5 is an upper electrode formed on the humidity sensitive film 4 and the auxiliary electrode 3 and is made of, for example, an Au thin film, and the upper electrode 5 is electrically connected to the auxiliary electrode 3. 6 is a sensor chip,
Reference numeral 7 designates external lead wires which are connected and fixed on the lower electrode terminal 2a and the upper electrode terminal 3a with solder 8.

In the humidity-sensitive element constructed in this way, the humidity-sensitive film 4 is sandwiched between the lower electrode 2 and the upper electrode 5, and the humidity-sensitive film 4 has an electric current with respect to the relative temperature. The change in capacitance value is caused by the change in the capacitance value between these electrode terminals 2a and 3.
It is taken out from the external lead wire 7 electrically connected to the top a.

[Problem to be solved by the invention]

However, in the moisture sensing element configured in this way, the external lead wires T are thermally connected to the electrode terminals 2a and 3m by soldering 8 and are mechanically fixed, so that there is no possibility of contact from the outside. Deterioration due to mechanical stress or vibration applied to the lead wire 7, repeated moisture absorption and drying,
There was a problem in that the deterioration due to temperature cycles caused poor contact. In addition, electrode terminals 2a, 3a
In a moisture-sensitive element that uses conductive rubber, for example, as a substitute for the external lead wire 7 connected to the outside, electrical connection is made by pressing the conductive rubber, but with such a configuration, Fatigue of conductive rubber.

There is a problem in that poor contact due to permanent deformation or poor connection due to vibration occurs. In addition, electrode terminals 2a, 3a
In a moisture-sensitive element that uses a conductive adhesive instead of solder 8 to connect the lead wire 7 to the external lead wire 7, if external mechanical stress or vibration is applied to the lead wire 7, the weak conductivity There are problems such as the fact that force is not directly applied to the adhesive part, which tends to cause peeling or contact failure during handling or actual use, poor no-undling properties, and lack of reliability.

Therefore, the present invention was made in view of the above-mentioned conventional problems, and its purpose is to strengthen the connection between the electrode terminal and the lead wire for external extraction, and to realize a highly reliable connection. An object of the present invention is to provide a moisture-sensitive element with a high temperature.

[Means to solve the problem]

The moisture sensing element according to the present invention is provided with a substantially U-shaped clip piece at the tip of an external lead wire formed on an insulating substrate and connected to at least one electrode terminal of the upper and lower electrodes. A shaped clip piece is inserted into the electrode terminal while holding the insulating substrate, and the contact part between the electrode terminal and one of the clip pieces is fixed to the conductive adhesive part, and the back side of the insulating substrate and the other clip piece are fixed. The contact part is fixed with a fixing adhesive part.

[Effect]

In the present invention, the insulating substrate is held between the U-shaped clip pieces of the lead wires and fixed to the adhesive portions on the front and back surfaces, so that the electrical connection and mechanical fixation are more reliable.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a moisture-sensitive element according to the present invention. FIG. 1(a) is a plan view of the main part, FIG. It is a cross-sectional view taken along line BB', and the same parts as in the previous figure are given the same reference numerals. In the same figure,
The external lead wire 9 has clip pieces 9a and 9b each having an opening approximately U-shaped in cross section at its tip, and its support portion 9C is provided with an insulating pad 10 as shown in FIG. is fixedly placed. These lead wires 9 are inserted into the lower electrode terminal 2a and the upper electrode terminal 5a with their U-shaped clip pieces 9m+9b holding the insulating substrate 1 between them.

In this case, the clip pieces 9m of these lead wires 9.

The dimensional tolerance of the opening 9b is set to such a size that the insulating substrate 1 can be inserted smoothly and pre-fixed.Thus, these lead wires 9 are formed by etching a thin stainless steel plate, for example. . Further, at the contact portion between the upper and lower electrode terminals 2m and 5a on the insulating substrate 1 and the clip piece 9a on one (front side) of each lead wire S, for example, a dispenser is used to make diacrylic, polyester, phenol, etc. Apply an appropriate amount of a conductive adhesive paste such as adhesive, rubber, silicone, or epoxy to the contact area between the back of the insulating substrate 1 and the clip piece 9b on the other (back side) of the lead wire 9. For example, apply an appropriate amount of epoxy adhesive paste with a dispenser and heat it to a temperature of 80°C.
Heat treatment is performed at -150°C for 5 minutes to 5 hours to cure the conductive adhesive part 11 and the fixing adhesive part 1, respectively.
2 is formed. Next, each of the lead wires 9 is inserted into the header 10, which is fixed to an insulator 13 made of glass or plastic, and is then covered with a cap 14 having an opening 14& as shown in FIG. 3, and then welded. Okay, complete the moisture sensing element.

According to such a configuration, on the front side of the insulating substrate 1,
One clip piece 9a of each lead wire 9 is thermally connected to the conductive adhesive part 11 on the upper and lower electrode terminals 2a and Sa, and the back side of the insulating substrate 1 is provided with a clip piece 9a of each lead wire 9. Since the other clip piece 9b is mechanically fixed to the fixing adhesive part 12, the sensor chip 6 and each lead wire 9 are mechanically firmly held and fixed, and electrically connected reliably. That will happen. Also, each lead wire 9 is
0, the terminal end 9d of the lead wire 9
Even if mechanical stress or vibration is applied to the header 10, it will be absorbed by the header 10, so that it will not be easily transmitted to the connection between the sensor chip 6 and the clip pieces 9a and 9b of each lead wire 9.
Therefore, the connection part is reliably protected. In addition, the cap 14 can prevent human hands and fingers from touching the surface of the sensor chip 60 and contaminating it when handling the sensor chip 6, resulting in a moisture-sensitive element that is stable over a long period of time.

〔Effect of the invention〕

As explained above, according to the present invention, at least one of the electrode terminals formed on the insulating substrate is connected to the insulating substrate through the U-shaped clip piece provided at the tip of the external lead wire. The contact part between the electrode terminal and one of the clip pieces is fixed by the conductive adhesive, and the contact part between the back surface of the insulating substrate and the other clip piece is fixed by the fixing adhesive. In particular, since the insulating board and the external lead wire are firmly connected and fixed, even if mechanical stress, vibration, etc. are applied to the insulating board or the external lead wire, the connection part will not be damaged. This eliminates the occurrence of contact failures and provides highly reliable electrical and mechanical connections. Also, insert a U-shaped clip piece into the insulating board,
Since the front and back surfaces are fixed to each other with adhesive, there is no heat shock caused by heating during conventional soldering and the influence of fluff residual liquid, so stable output can be obtained over a long period of time, and the manufacturing process It is possible to obtain extremely excellent effects such as shortening the time period and being able to provide a moisture-sensitive element at low cost.

[Brief explanation of the drawing]

FIGS. 1(a), (b), and (e) are plan views of essential parts showing the structure of a moisture-sensitive element according to an embodiment of the present invention, and FIG.
A' line sectional view, its B-B' line sectional view, Figure 2 (,)
, (b) is a plan view of the humidity sensing element in Figure 1, a plan view seen from the side, Figure 3 is a perspective view showing the assembly structure of the humidity sensing element in Figure 1, Figure 4 (a), ( b) and (e) are a plan view of main parts showing the structure of a conventional moisture-sensitive element, a sectional view taken along the line AA', and a sectional view taken along the line BB'. 1... Insulating substrate, 2... Lower electrode, 2a ・
... Electrode terminal, 4 ... Moisture sensitive membrane, 5 ... Upper electrode, 5a ... Electrode terminal, 6 ... Sensor chip,
9... External lead wire, 91119b++e
e*Clip piece, 96 #11 @ Support part, 9
d...Terminal part, 10...Header, 11...
Conductive adhesive part, 12...Fixing adhesive part, 13.
...Insulator, 14...Cap, 14a...
Aperture. (b) Figure 2 Figure 3

Claims (1)

[Claims] a lower electrode formed on an insulating substrate, a moisture-sensitive film formed on the lower electrode, an upper electrode formed on the moisture-sensitive film, and upper and lower electrodes formed on the insulating substrate. electrode. An external lead wire having a substantially U-shaped clip piece that holds at least one electrode terminal together with the insulating substrate, and a conductive adhesive bonded and solidified to the contact portion between the electrode terminal and one of the clip pieces. and a fixing adhesive portion bonded and solidified to a contact portion between the back surface of the insulating substrate and the other clip piece.