JPH11160268A - Humidity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a humidity sensor which can be miniaturized, whose performance can be increased and whose productivity is improved. SOLUTION: Hollow containers which are nearly rectangular parallopiped- shaped are used as a cap 7 in which a temperature transducer 8 for a humidity sensing device 2 is housed and as a cap 7 in which a temperature transducer 8 for a temperature compensator 3 is housed, and the caps 7 are arranged on a holder 1 so as to be close to each other. As a result, also the temperature transducers 8 inside the caps 7 are brought close to each other, and their installation environment becomes identical. In addition, when lead wires 10 of the temperature transducers 8 are connected to external interconnections 15, a lead frame is interposed between them so as to automate their connection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a humidity sensor for measuring temperature, humidity, gas concentration, and the like using a pair of thermosensitive elements such as a thermistor.

[0002]

2. Description of the Related Art A humidity sensor using a heat-sensitive element such as a thermistor as a sensor element is widely used as a humidity sensor for measuring humidity in a microwave oven. This humidity sensor self-generates heat in a thermosensitive element in the outside air atmosphere and in a sealed atmosphere cut off from the outside air, and detects a change in the resistance value of both thermosensitive elements to detect the amount of water vapor in the air atmosphere (absolute humidity).
Is measured.

Various types of humidity sensors using a heat-sensitive element have been conventionally proposed. In short, the heat-sensitive element is incorporated in two cases, and a small hole is formed in one of the cases to open the outside air. The other case is hermetically sealed, and the former is combined as a humidity detector and the latter as a temperature compensator.

FIG. 6 shows an example of a humidity sensor. In this example, the thermal element 2 attached to the stem 21 as shown in FIG.
2 is covered with a metal cap 23, a hole 24 is made in a part of the cap 23, and this is used as a moisture detector 25.
A temperature compensator 26 having no holes is prepared, and the humidity sensor 25 and the temperature compensator 26 are housed in a metal case 27. According to this example, the metal case 27 has a tubular shape covered with a metal plate having a flange 28 at one end and a hole 29 at the other end as shown in FIG. A metal tube 31 having a metal plate 30 fixed at one end is press-fitted, the humidity sensor 25 and the temperature compensator 26 are fixed thereto, and the metal cover 32 is fixed to the flange 28 so as to cover the upper surface of the metal case 27. (See Japanese Utility Model Publication No. 4-35806).

[0005] The conventional structure of the humidity sensor is not necessarily the same as that shown in FIG.
Although the humidity sensor and the temperature compensator are separately manufactured as in the above, and this is not limited to an example in which this is incorporated in a metal case, most conventional sensors include a cap, a case, and other parts for covering the heat-sensitive element. Metal components were used for the constituent members of the sensor including the above, and the stem and the metal cap were welded and sealed with a hermetic seal.

[0006]

FIGS. 6 and 7 show an embodiment of the present invention.
As shown in the structure shown in FIG.
When cylindrical caps are used for the caps, the distance between the thermosensitive elements accommodated in each cap increases, and the environmental conditions at the time of measurement do not always match for both thermosensitive elements, which is a cause. Thus, there is a problem that the measurement accuracy is affected.

[0007] Furthermore, recently, the demands from users regarding humidity sensors have become severe, and in addition to downsizing and high performance, there has been a strong demand for low price, and manufacturers have been pressing for improvement for high productivity. That is the fact. In the structure shown in FIG. 6, attaching the humidity sensor 25 and the temperature compensator 26 to the heat equalizing metal plate 30 and connecting external wires to the lead wires of the heat sensitive elements of the humidity sensor 25 and the temperature compensator 26. Seems to be difficult to automate.

[0008] It is an object of the present invention to provide a humidity sensor which has been reduced in size and performance, improved in measurement accuracy, and further improved in productivity.

[0009]

In order to achieve the above object, a humidity sensor according to the present invention comprises a humidity sensor and a temperature compensator on a holder. The container has a thermo-sensitive element housed in a cap attached to a holder, one of the caps is hermetically sealed, and the other cap has a small hole that communicates with the outside air. The heat-sensitive element is housed in a cap that communicates with the outside air, the lead wire of the heat-sensitive element is drawn out through a holder, and the temperature compensator houses the heat-sensitive element in a hermetically sealed cap. The lead wire of the heat-sensitive element is drawn out through the holder, and the caps of the humidity sensor and the temperature compensator are substantially rectangular parallelepiped hollow containers. Arrangement It is those that have been.

[0010] The cap is welded to the holder.

The cap has a base for sealing the inside of the cap, and the lead wire of the thermosensitive element is housed in the cap while being held by the base, and the lead wire is drawn out of the cap through the base. The base is welded to the plate surface of the holder.

Further, each lead wire of the humidity sensor and the temperature compensator drawn out through the holder is connected to an external wiring via a lead frame.

Each lead wire serving as a common terminal of the humidity sensor and the temperature compensator is commonly connected to one lead frame.

A lead frame which is an output terminal of the humidity sensor, two leads which are a common terminal of the humidity sensor and the temperature compensator, and a lead wire which is an output terminal of the temperature compensator are a lead frame. Are fixed to three parallel segments, respectively.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a humidity sensor according to the present invention is provided with a humidity sensor 2 and a temperature compensator 3 in a holder 1, and the hood 4
In addition, a cover 5 is attached to the back surface of the holder 1, and the external wiring 6 is electrically connected to the humidity detector 2 and the temperature compensator 3 in the cover 5.

In the present invention, as shown in FIG. 2, the humidity sensor 2 and the temperature compensator 3
The cap 7 is locked by a base 9, and a pair of lead wires 10, 10 is attached to the base 9. In the present embodiment, a glass-sealed microchip thermistor is used for the thermal element 8. The heat-sensitive element 8 has a pair of platinum wires as the terminal wires 11, and the platinum wires are drawn out from both ends of the heat-sensitive element 8 in opposite directions, and each terminal wire 11 is held at both ends in the longitudinal direction of the base 9. Are connected to the pair of lead wires 10, 10, respectively.

The cap 7 is a substantially rectangular parallelepiped hollow container having curved edges at both ends, and has an opening on the lower surface. The opening edge is engaged with the base 9 so that the thermosensitive element 8 is placed in the cap 7. It is sealed.

Although a small hole 12 is opened in a part of the cap 7 used as the humidity sensor 2 to communicate the inside of the cap 7 with the outside air, the cap 7 used for the temperature compensator has no small hole. , The base 9 is hermetically sealed. Although it is convenient for the holder 1 to be welded to the cap, it is desirable to use a metal plate having excellent thermal conductivity as much as possible.
A pair of insertion holes 13 into which the lead wires 10 and 10 of the humidity sensor 2 and the temperature compensator 3 are to be inserted are opened close to each other on the plate surface of the holder 1. Reference numerals 3 denote respective lead wires inserted into the insertion holes 13 and arranged close to each other, and are fixed to the plate surface of the holder 1 by welding.

In the humidity sensor 2 and the temperature compensator 3, the lower surface of each base 9 is welded to the plate surface of the holder 1, and the weldability between the base 9 and the plate surface of the holder 1 is welded. If it is not good, a part of the plate surface of the holder to which the base is to be welded is hit with a punch or the like, and a projection 14 due to the dent is attached to increase the joining strength by welding. Spot welding is sufficient, but if the entire circumference of the base 9 is seam-welded, it can be more reliably fixed.

FIG. 3 shows the lead wires 10, 10,... Of the humidity sensor 2 and the temperature compensator 3 drawn out from the lower surface of the holder 1.
And how to connect to the external wiring 15 having an output line and a common line.

In the present invention, each lead wire 1 of the humidity sensor 2 and the temperature compensator 3 is interposed with a lead frame 16 interposed therebetween.
0 and the external wiring 15. FIG.
2A, two lead wires 10 (hereinafter referred to as 10a, 10b, 10c, and 10d) are drawn out of the back surface of the holder 1 to the humidity detector 2 and the temperature compensator 3, respectively. , One is an output terminal and the other is a common terminal.

When the holder 1 on which the humidity sensor 2 and the temperature compensator 3 are mounted is carried into the conveyance line of the lead frame 16, the humidity sensor 2 and the temperature compensator 3 are moved in the conveyance direction of the line indicated by the arrow. Is inclined by about 45 °, one lead wire 10a, two lead wires 10b, 10c, and one lead wire 10d correspond to the three segments 16a to 16c of the lead frame 16, respectively. Become like

In FIG. 3B, each of the lead wires 10a to 10a
The terminal of 10d is bent at a right angle in the direction of the segments 16a to 16c, and the bent portion is welded to the corresponding segment, and each segment 16a to 16c is separated from the tie bar 17 at its base as shown in FIG. And then external wiring 1
The crimping elements of the fifth output terminal wires 15a and 15b and the common terminal wire 15c are fixed to the respective segments 16a to 16c by welding or ultrasonic bonding.

That is, in FIG. 3C, three segments 16a, 16b and 16c are sequentially arranged in the first and second stages.
In the third and third stages, for example, the first output terminal line 15 of the external wiring 15 is connected to the first stage seg cement 16a to which one lead wire 10a serving as the output terminal of the humidity sensor 2 is attached.
a to the second stage segment 16b to which the two leads 10b and 10c serving as a common terminal of the humidity sensor 2 and the temperature compensator 3 are attached.
5b and a third stage segment 16 to which one lead wire 10d serving as an output terminal of the temperature compensator 3 is attached.
The second output terminal line 15c of the external wiring 15 is connected to c.

Next, as shown in FIG. 4, a cover 5 is provided on the back side so as to cover the connection between the lead wire 10 and the external wiring 15.
Is attached to complete the humidity sensor. However, as shown in FIG. 5, a hood 4 may be attached to the upper surface side of the holder 1 so as to cover the humidity sensor 2 and the temperature compensator 3. On the upper surface of the hood 4, a number of small holes 18, 18,... Are opened to maintain air permeability inside and outside the hood.

According to the present invention, since the cap 7 having a substantially rectangular parallelepiped shape is used as a container for accommodating the heat-sensitive element 8, when the combination of the humidity sensor 2 and the temperature compensator 3 is installed on the holder 1, the humidity sensor is used. 2 and the thermosensitive element 8 of the temperature compensator 3 can be arranged very close to each other, and the installation environment of the thermosensitive elements 8 and 8 can be matched, thereby improving the measurement accuracy. it can. In addition, since the humidity sensor 2 and the temperature compensator 3 are separate bodies, the combination of the two devices can be freely selected to match the characteristics of the thermosensitive elements 8.

Table 1 shows the relationship between the material of the holder and the sensor characteristics. Table 1 shows the balance stability time of the sensor when the base of the cap is attached to the holder by welding or "caulking", the stable state of zero balance, and the results of the mounting test. The material of the base of the cap is nickel-plated iron.

[0028]

[Table 1] Zero balance: Output stable state when environmental temperature is changed Balance stabilization time: Output voltage stabilization time

As is clear from Table 1, it was found that a nickel-plated Bs plate which was selected as the material of the holder and which was welded to the cap was the most excellent. Regarding the relationship between the material of the holder and the superiority of the sensor characteristics, there is a correlation between the sensor characteristics and the thermal conductivity of the metal used for the holder, and the better the thermal conductivity of the metal plate, the better the sensor characteristics. .

When connecting the lead wires of each thermosensitive element 8 to external wiring, a lead frame segment is attached to each lead wire and external wiring is connected to this segment. It is possible to automate the connection of each lead wire, output wire, and ground wire as well as the connection between the lead wires that are the terminals, and the work from assembly of the parts to the wiring process is automatically performed on the line be able to.

[0031]

Therefore, according to the present invention, there is an effect that a small, high-performance humidity sensor can be manufactured with high productivity and can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention.

FIG. 2 is a configuration diagram of a humidity detector and a temperature compensator.

FIG. 3 is a diagram showing a procedure for connecting a lead wire to an external wiring.

FIG. 4A is a sectional side view showing an embodiment of the present invention, and FIG. 4B is a plan view thereof.

FIG. 5 is a cross-sectional side view showing another embodiment.

FIG. 6 is a sectional view of a conventional humidity sensor.

FIG. 7 is a diagram showing a main part of a conventional humidity sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Holder 2 Humidity detector 3 Temperature compensator 4 Hood 5 Cover 6 External wiring 7 Cap 8 Heat sensitive element 9 Base 10, 10a-10d Lead wire 11 Terminal wire 12 Small hole 13 Insertion hole 14 Projection 15 External wiring 16 Lead frame 16a- 16c segment 17 tie bar

Claims (6)

[Claims] 1. A humidity sensor having a humidity sensor and a temperature compensator on a holder, wherein the humidity sensor and the temperature compensator each contain a heat-sensitive element in a cap attached to the holder. The inside of one of the caps is hermetically sealed, the other cap has a small hole that communicates with the outside air, and the humidifier has a thermosensitive element housed in the cap that communicates with the outside air. The lead wire of the element is drawn out through the holder, the temperature compensator contains the thermosensitive element in a hermetically sealed cap, and the lead wire of the thermosensitive element is drawn out through the holder, A humidity sensor characterized in that the caps of the humidity sensor and the temperature compensator are hollow containers having a substantially rectangular parallelepiped shape, and are arranged in parallel so that one long side is close to each other. 2. The humidity sensor according to claim 1, wherein the cap is welded to the holder. 3. The cap has a base for sealing the inside of the cap, and a lead wire of the thermal element is held in the cap while being held by the base, and the lead wire is drawn out of the cap through the base. The humidity sensor according to claim 1 or 2, wherein the base is welded to a plate surface of the holder. 4. The humidity sensing device and the temperature compensator lead wires drawn out to the outside through the holder are connected to external wiring via a lead frame, respectively. A humidity sensor according to claim 1. 5. The humidity sensor according to claim 4, wherein each lead wire serving as a common terminal of the humidity sensor and the temperature compensator is commonly connected to one lead frame. . 6. A lead wire which is an output terminal of the humidity sensor, a common terminal of the humidity sensor and the temperature compensator, and two lead wires and a lead wire which is an output terminal of the temperature compensator are leads. The humidity sensor according to claim 4, wherein the humidity sensor is fixed to each of three parallel segments of the frame.