JPH05332826A - Infrared ray detector - Google Patents

Abstract

PURPOSE:To enhance heat transfer efficiency from a heat-collecting plate to a heat-sensing resistor for improving detection sensitivity and reliability of an infrared ray detector and for reducing cost. CONSTITUTION:A temperature-sensing part 31 is formed by covering a heat- sensing resistor 2 with a covering layer 22, on the other hand a recessed part 5a where the heat-sensing part 31 is engaged is formed at the heat-collecting plate 15, and then the temperature-sensing part 31 is press-contacted and fixed to the recessed part 5a by caulking. Therefore, heat which is collected at the heat-collecting plate 15 is directly transferred to the heat-sensing part 31 via the press-contacted part, thus enhancing heat transfer efficiency and improving infrared ray detection sensitivity and response.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared detector using a resistor.

[0002]

2. Description of the Related Art Conventionally, infrared detectors are well known.
It is widely used as a temperature control sensor for air conditioning equipment. The structure of an infrared detector of this kind is shown in FIG. 3 in an exploded perspective view.

A heat insulating material 6 is provided on an inner wall of a box-shaped case 10 having an infrared ray incident surface in an opening, and a closed space is formed in the opening by being closed by an infrared transmitting filter 4.
A heat collecting plate 15 is provided inside the infrared transmission filter 4, and a thermistor element 3 serving as an infrared detecting element is fixed to the backside of the heat collecting plate 15 substantially in the center thereof, and a lead wire 11 is pulled out from the thermistor element 3. , The board 19 below the case 10
It is connected to the. The heat collecting plate 15 includes an infrared absorbing layer 51 that absorbs the heat of the infrared rays 12 and an infrared light receiving plate 5 that collects the heat, and the heat collected by the heat collecting plate 15 is transferred to the thermistor element 3.

FIG. 4 shows the structure for fixing the heat collecting plate 15 and the thermistor element 3 in contact with each other. The thermistor element 3 is formed by covering the thermistor chip 2 as a temperature sensitive resistor with a hard coating layer 22 made of a thermosetting resin material such as epoxy resin or a glass material. The thermistor element 3 is adhesively fixed to the heat collecting plate 15 with an adhesive.

In this type of infrared detector, when infrared rays 12 emitted from, for example, the floor or wall of a room enter and are collected by a heat collecting plate 15, the heat is covered by the adhesive layer 25 and the thermistor element 3. The heat is transferred to the thermistor chip 2 through the layer 22. Due to this heat, the resistance value of the thermistor chip 2 changes according to the temperature change, and the change of the resistance value is transmitted to the circuit on the substrate 19 by the lead wire 11, and the infrared detection signal is output as a voltage change. It

[0006]

However, according to this structure, a work step of adhering the heat collecting plate 15 and the thermistor element 3 is required, and it takes a long time for the adhesive layer 25 to dry. However, the manufacturing cost is high. Also, the adhesive layer
Since 25 is interposed between the heat collecting plate 15 and the thermistor element 3, the heat transfer to the thermistor element 3 is delayed because the adhesive layer 25 has a heat capacity when the infrared ray 12 enters. The thermal efficiency was poor. In addition, the coating layer 22 of the thermistor element 3 has a ridged shape on the upper side of the thermistor chip 2, and since the adhesive layer 25 is also interposed between the heat collecting plate 15 and the thermistor chip 2, the distance becomes long. The heat transfer function was further deteriorated, and the detection sensitivity and responsiveness were deteriorated.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide an inexpensive infrared detector having high infrared detection sensitivity, high reliability, and high reliability.

[0008]

In order to achieve the above object, the present invention is configured as follows. That is,
The present invention comprises a heat collecting plate for collecting heat of infrared rays incident from the outside, in an infrared detector in which an infrared detecting element is fixed in contact with the heat collecting plate, the infrared detecting element is a temperature-sensitive resistor, A temperature sensitive portion is formed by including a coating layer that coats the temperature sensitive resistor, and a concave portion into which the temperature sensitive portion of the infrared detecting element is fitted is formed in the heat collecting plate, and the concave portion is formed in the concave portion. It is characterized in that the temperature-sensitive portion of the infrared detection element is fixed to the concave portion by caulking while being fitted in the temperature-sensitive portion.

[0009]

In the present invention having the above construction, the temperature sensing portion of the infrared detecting element is fitted into the concave portion formed on the heat collecting plate, and then the temperature sensing portion is fixed to the heat collecting plate by caulking. Therefore,
Infrared rays enter from the outside, and the heat collected in the heat collecting plate is directly transmitted to the temperature sensing portion through the caulking pressure contact portion, so that the heat transfer efficiency is increased and the sensitivity and responsiveness of infrared ray detection are enhanced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the same members as those in the conventional example are designated by the same reference numerals, and the duplicate description will be omitted. FIG. 1 shows a sectional view of an embodiment of an infrared detector according to the present invention.
FIG. 2 shows a detailed cross-sectional view of an essential part of this infrared detector.

Thermistor element 3 as an infrared detecting element
Is the thermistor chip 2 as a temperature sensitive resistor as in the past.
However, in this embodiment, the material of the coating layer 22 is an epoxy resin or the like having elasticity. By coating the thermistor chip 2 with the coating layer 22, the temperature sensitive portion 31 of the thermistor element 3 is formed. The thermistor chip 2 has lead wires to connect to the circuit of the substrate 19.
The end of 11 is fixed by soldering. On the other hand, as the infrared light receiving plate 5 constituting the heat collecting plate 15, in the present embodiment, a metal plate whose main component is aluminum is used. The infrared light receiving plate 5 is formed with a recess 5a into which the temperature sensitive portion 31 is fitted, and the temperature sensitive portion 31 is caulked and fixed in pressure contact with the recess 5a. The heat collecting plate 15 is formed by providing the infrared absorbing layer 51 on the upper surface of the infrared receiving plate 5. The infrared absorbing layer 51 is preferably provided after caulking the temperature sensing part 31 in the recess 5a of the infrared receiving plate 5. desirable.

With the above structure, in the present embodiment, the infrared ray receiving plate 5 constituting the heat collecting plate 15 and the temperature sensing portion 31 of the thermistor element 3 are arranged.
Since at least one part is in direct contact with the heat collecting plate
The heat collected in 15 is quickly conducted to the temperature sensing section 31 to improve the heat transfer efficiency, so that the detection sensitivity of the infrared rays 12 is improved. Compared to the conventional case where the adhesive layer 25 is interposed between the heat collecting plate 15 and the thermistor element 3, the detection sensitivity is 8
It was confirmed by the experiment that the cost was improved. Further, the thermistor element 3 is crimped and fixed to the concave portion 5a of the heat collecting plate 15, and since the coating layer 22 in the temperature sensing portion 31 is elastically deformed and held by the heat collecting plate 15, the pressure fixing is not performed. It can be done reliably.

In comparison with the conventional method which required about 1 hour to dry the adhesive, in the present embodiment, the infrared ray receiving plate 5 is caulked with a jig or the like to press the temperature sensitive portion 31 of the thermistor element 3 into pressure contact. Since the manufacturing efficiency is improved and the manufacturing cost is reduced by fixing in a short time, it is possible to provide an infrared detector which is inexpensive and has a high detection sensitivity.

The present invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted. For example, the infrared light receiving plate 5 is made of a metal containing aluminum as a main component, but any other material having a high thermal conductivity can be substituted.

Further, although the resistor having a negative temperature coefficient of resistance such as a thermistor chip is used as the temperature sensitive resistor 2 in the present embodiment, another resistor having a negative temperature coefficient of resistance may be used. Alternatively, nickel or platinum having a positive temperature coefficient of resistance may be used.

Further, although epoxy resin is used as the material of the coating layer 22 of the temperature sensitive resistor 2, other resins,
For example, a silicone resin or the like can be used instead. Coating layer 22
May be made of glass material, but in the case of glass material, the heat collecting plate 15
Since the thermistor element 3 may be damaged when the temperature sensitive portion 31 is caulked and fixed under pressure, it is more preferable to use the resin material as the material of the coating layer 22 as described above.

[0017]

According to the present invention, since the temperature sensitive portion of the infrared detecting element is crimped and fixed to the concave portion of the heat collecting plate, the heat collected in the heat collecting plate is directly contacted from the crimping pressure contact portion. Since it is conducted to the temperature-sensitive part, the heat transfer efficiency is increased, and the infrared detection sensitivity and response are improved.

Since the step of adhering can be omitted in the manufacturing process as well, the manufacturing efficiency is improved and the manufacturing cost is reduced, so that it is possible to provide an infrared detector which is inexpensive and has high performance.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of an infrared detector according to the present invention.

FIG. 2 is a detailed cross-sectional view of a main part of the infrared detector according to the embodiment.

FIG. 3 is an exploded perspective view of a conventional infrared detector.

FIG. 4 is a detailed cross-sectional view of a main part of a conventional infrared detector.

[Explanation of symbols]

 1 infrared detector 2 thermistor chip (temperature sensitive resistor) 3 thermistor element (infrared detecting element) 5 infrared receiving plate 5a recess 15 heat collecting plate 22 coating layer 31 temperature sensing part

Claims (1)

[Claims] 1. An infrared detector comprising a heat collecting plate for collecting heat of infrared rays incident from the outside, wherein the infrared detecting element is in contact with and fixed to the heat collecting plate, wherein the infrared detecting element is a temperature sensitive resistor. And a coating layer that covers the temperature-sensitive resistor to form a temperature-sensitive portion, and the heat collecting plate is formed with a recess into which the temperature-sensitive portion of the infrared detection element is fitted. An infrared detector characterized in that a temperature-sensitive portion of an infrared detection element is fitted into the concave portion, and the temperature-sensitive portion is press-contacted and fixed to the concave portion by caulking.