JP3089512B2 - Infrared detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared detecting element used for detecting a human body by detecting infrared rays radiated from a human body.

[0002]

2. Description of the Related Art Conventionally, as this kind of infrared detecting element, for example, those shown in FIGS. 8 and 9 have been proposed (FIG. 9 is a plan view of FIG. 8). This conventional device has, for example, four infrared receiving surfaces 40 (40a to 40a).
A substrate 27e having d) formed on the front side is supported on a predetermined support plate 25 having terminals 24 and the like by support portions 26 having a small cross-sectional area so as to be provided with a gap 28 therebetween. It is. With such a structure, infrared detection can be performed on each of the four independent infrared receiving surfaces 40a to 40d. Further, since the gap 28 is formed between both the substrate 27e and the support plate 25, the apparent heat capacity of the substrate 27e can be reduced, and the responsiveness of infrared detection by infrared reception can be enhanced. Conventionally, the four infrared receiving surfaces 40a to 40d are configured so that the positive and negative polarities are alternately different from each other.
There has also been proposed a configuration in which a negative detection signal is output when infrared light is received at 0d, and a positive detection signal is output at the other two infrared light receiving surfaces 40b and 40d.

[0003]

SUMMARY OF THE INVENTION In the above prior art,
For example, in a state in which four independent detection areas are formed by the four infrared receiving surfaces 40a to 40d, for example, when a small animal that emits infrared light is detected only by the negative-polarity infrared receiving surfaces 40a and 40c, the For example, as shown by the solid line in FIG. 10, only the detection signal exceeding the negative threshold twice must be output from the infrared detection element. However, actually, the incident heat when infrared light is received by the infrared light receiving surface 40a is transmitted to the substrate 27e and is also transmitted to the positive infrared light receiving surface 40b to increase the temperature. May perform substantially the same operation as when infrared light is received, that is, crosstalk may occur. In such a case, as indicated by the dashed line in FIG.
A detection signal N (voltage signal) that largely swings toward the positive electrode side from the infrared light receiving surface 40b is output. As a result, in the related art, because a detection signal different from the original output waveform is output, erroneous judgments such as the detection of a small animal, which is judged as a human body detection, etc. Had difficulties.

The present invention has been proposed in view of the above points, and eliminates crosstalk between a plurality of infrared light receiving surfaces so as not to cause an error in infrared detection processing. The aim is to provide an infrared sensing element that can be used.

[0005]

According to the first aspect of the present invention, there is provided an infrared detecting element according to the present invention, wherein a substrate having a plurality of infrared light receiving surfaces formed on a surface thereof includes: An infrared sensing element provided on a support plate with a gap therebetween, wherein a position between the plurality of infrared receiving surfaces is such that the heat of the substrate is released to the support plate side. Is provided with one or more connecting parts .
This connection is made of a material with relatively good thermal conductivity.
Has been established . The connecting portion may be configured as a supporting portion for supporting the substrate on a supporting plate, as described in claim 2. Further, as a specific arrangement mode of the infrared receiving surface, as described in claim 3, it is possible to adopt a mode in which a total of four cross lattices are provided on the substrate. It may be provided at the center or near the center between the infrared receiving surfaces. Further, the plurality of infrared light receiving surfaces may be configured so that their polarities are alternately different, as described in claim 4.

[0006]

[0007]

According to the first aspect of the present invention, there is provided an infrared detecting element according to the present invention, wherein infrared light is received at any one of a plurality of infrared receiving surfaces, and the incident heat at that time is transmitted to the substrate. Is generated, the heat is dissipated to the support plate side via the connection portion provided between the infrared receiving surfaces. Therefore, unreasonable heat conduction from the infrared receiving surface that has received infrared light to another infrared receiving surface is suppressed, and crosstalk between the two is appropriately prevented. on the other hand,
The connection part for releasing heat from the substrate to the support plate is only partially provided at a position between the infrared receiving surfaces, and the apparent heat capacity of the substrate is integrated with the support plate. Therefore, there is no problem that the response of infrared detection is reduced.

[0008]

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a main part of an infrared detecting element 2 according to the present invention, and FIG. 2 is a plan view of the main part. The infrared detecting element 2 includes a shield case 21, a shield case 21
The optical filter 23 disposed to close the opening window 22 on the tip (upper end) side of the case body 21a, and the terminal 2 provided through the base 21b of the shield case 21.
4, a FET mounted below the support plate 25, a substrate 27 mounted above the support plate 25 through a plurality of small-area support portions 26,. Infrared receiving surfaces 20 provided on the surface of
And so on.

[0010] Of the above components, the optical filter 23 passes only infrared rays in a wavelength range radiated from a human body and blocks electromagnetic waves in other wavelength ranges. The substrate 27 is made of, for example, ceramic or the like, and is formed in a plane rectangular shape as shown in FIG. 2, and four infrared receiving surfaces 20 (20a to 20d) are provided on the surface thereof in a cross lattice shape. Have been. These four infrared receiving surfaces 20a to 20d
For example, a pyroelectric element type in which the voltage value of the output voltage changes based on a temperature rise due to the reception of infrared rays is applied, but these are configured so that each can independently output an individual infrared detection signal. I have. The four infrared receiving surfaces 20a to 20d are provided so that their positive and negative polarities are alternately different. For example, the two infrared receiving surfaces 20a and 20c output a negative voltage signal as an infrared detection signal. , The other two infrared receiving surfaces 20b, 20d
Outputs a positive voltage signal as an infrared detection signal.

The support portions 26 are composed of a substrate 27 and a support plate 25.
The support 27 is for supporting the substrate 27 so as to form a gap 28 between them, and as shown in FIG. The other support portion 26 is disposed at the center
A is provided at the center or substantially at the center between the four infrared receiving surfaces 20a to 20d. This support 26
A corresponds to the connecting portion according to the present invention, and is made of a material having relatively good thermal conductivity.

The infrared detecting element 2 having the above-described configuration is incorporated in, for example, an infrared type human body detector K having a configuration shown in FIG. 3 and then used in a mode as shown in FIG. That is, as shown in FIG. 4, the infrared type human body detector K forms four detection areas Aa to Ad arranged in a vertical and horizontal lattice as shown in FIG. It is configured to The detection areas Aa to Ad correspond to the four infrared receiving surfaces 20a to 20d of the infrared detecting element 2, respectively. The detection areas Aa and Ac correspond to the infrared receiving surfaces 20a and 20c in FIG. Correspond to the infrared receiving surfaces 20b and 20d, respectively.

An infrared human body detector K shown in FIG. 3 includes an amplifier 3 for amplifying an infrared detection signal output from the infrared detection element 2 and a band-pass filter for removing unnecessary frequency components from the amplified detection signal. 4, a window comparator circuit 5, a timer circuit 6, a pulse count circuit 7, an output circuit 8, and the like. The window comparator circuit 5 generates a detection pulse when an infrared detection signal output from the bandpass filter 4 has an output level exceeding a predetermined threshold value. The timer circuit 6 starts counting time when the first detection pulse is transmitted from the window comparator circuit 5, and when a predetermined time period is reached, a predetermined time-up signal is sent to the pulse counting circuit. 7, the timer is reset at the same time.
The pulse count circuit 7 counts the number of detection pulses generated by the window comparator circuit 5 while the timer circuit 6 is counting time. When a time-up signal is received from the timer circuit 6, the count is counted. Although the number is canceled, for example, when the generation of three detection pulses is counted before the time-up signal is received, a human body detection determination signal is output to the output circuit 8 at that time. The output circuit 8 outputs a desired signal such as a relay signal for turning on the luminaire R as an example of a control target when the human body detection determination signal is received.

The infrared human body detector K configured as described above is provided so that the detection beam b is substantially parallel to the floor F as shown in FIG. Then, at a position separated by a desired distance L for performing human body detection, of the four detection areas Aa to Ad, the lowest detection area Ad is located below the floor surface F, and the other three detection areas are different. Aa ~
It is set and used so that Ac is located above the floor surface F. In this setting state, as shown in FIG. 5A, when a tall human body moves on the floor F, the human body enters each of the three detection areas Aa to Ac in this order. Therefore, in such a case, the three infrared receiving surfaces 20a of the infrared detecting element 2 shown in FIG.
5 through 20c, the infrared rays are received.
A detection signal as shown in FIG. As a result, an infrared detection signal exceeding the threshold value is output three times in total, so that the infrared human body detector K determines this infrared detection as detection of a human body and turns on the lighting apparatus R. Outputs a relay signal.

On the other hand, as shown in FIG. 6A, when a small animal such as a short dog or cat moves on the floor F, the small animal sequentially enters only the two detection areas Aa and Ac. . In such a case, infrared light is received only on the two infrared light receiving surfaces 20a and 20c of the infrared detecting element 2 shown in FIG. Thus, when infrared light radiated from a small animal is received by one infrared light receiving surface 20a, heat due to the infrared light is transmitted through the substrate 27, and a part of this heat is provided in the center of the substrate 27. It escapes to the support plate 25 side via the provided support part 26A. Therefore, the infrared receiving surface 20
a, the amount of heat conducted to the other infrared receiving surface 20b side is reduced, and the other infrared receiving surface 20b not receiving infrared light
Output of an infrared detection signal from the device. As a result, as shown in FIG. 6B, the detection signal of the infrared ray due to the passage of the small animal becomes a signal exceeding the threshold value only twice, and is clearly distinguished from the case of FIG. 5B in the case of the human body detection. In addition, the detection of a small animal can be appropriately prevented from being erroneously determined as the human body detection.

In the above embodiment, the case where the supporting portion 26A for supporting and providing the substrate 27 on the supporting plate 25 is made to function as the connecting portion is described. However, there is no need for such a configuration. In short, any means may be used as long as it connects the substrate 27 and the support plate 25 so that the heat of the substrate 27 can be released to the support plate 25. The specific number of the connection portions (support portions) 26A is not limited to one, and a plurality of connection portions (support portions) may be provided .

FIG. 7 shows another configuration of the infrared detecting element . In the configuration shown in the figure, instead of the support portion (connection portion) 26A described in FIG. 1 and FIG. 2 and the like, the substrate 27 is provided at the center or substantially the center between the four infrared receiving surfaces 20a to 20d. An opening 30 is provided. Even with such a configuration, for example, when the infrared light receiving surface 20a receives infrared light, heat conduction from this infrared light receiving surface 20a to another infrared light receiving surface 20b or the like is suppressed, and as shown in FIGS. The same effect of preventing crosstalk as in the embodiment can be obtained.

[0018]

As understood from the foregoing description, according to the infrared detector element according to the present invention described in claims 1 to 4, by eliminating the crosstalk caused between the plurality of infrared ray receiving surface, infrared There is an effect that the detection process can be appropriately used for a human body detection application without causing an error in the detection process. In particular, the present invention, since it is intended to be prevented by forming the connecting portion for connecting the cross talk between the substrate and the support plate part, with respect to heat insulation between the substrate and the support plate almost no difference with the conventional In addition, since the heat capacity of the substrate can be reduced, there is an advantage that a problem such as a decrease in responsiveness of infrared detection does not occur.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an infrared detecting element according to the present invention.

FIG. 2 is a plan view of a main part of the infrared detecting element shown in FIG. 1;

FIG. 3 is a block diagram showing an example of a hardware configuration of an infrared human body detector using the infrared detection element according to the present invention.

FIG. 4 is an explanatory view showing an example of a use state of the infrared human body detector shown in FIG. 3;

FIG. 5A is an explanatory diagram showing a state in which a human body is detected, and FIG. 5B is an explanatory diagram of a detection signal output at that time.

6A is an explanatory diagram illustrating a state in which a small animal is detected, and FIG. 6B is an explanatory diagram of a detection signal output at that time.

FIG. 7 is a main part plan view showing another example of the infrared detection element .

FIG. 8 is a sectional view of an essential part showing an example of a conventional infrared detecting element.

FIG. 9 is a plan view of a main part of the infrared detecting element shown in FIG. 8;

FIG. 10 is an explanatory diagram showing an example of a detection signal obtained by a conventional infrared detection element.

[Explanation of symbols]

 2 Infrared detecting element 20 (20a to 20d) Infrared light receiving surface 21 Housing case 23 Optical filter 25 Support plate 26 Support portion 26A Support portion (connection portion) 27 Substrate 28 Gap portion 30 Opening

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Claims (4)

(57) [Claims] A substrate having a plurality of infrared receiving surfaces formed on a surface thereof is an infrared detecting element provided on a support plate with a gap therebetween, wherein the plurality of infrared receiving surfaces are mutually connected. the between positions, the connecting portion for connecting the substrate so as to release the heat of the substrate on the support plate side and the support plate is provided with one or more, the connection portion is thermally
An infrared detecting element comprising a material having relatively good conductivity . 2. An infrared detecting element according to claim 1, wherein said one or more connecting portions are constituted as supporting portions for supporting the substrate on a supporting plate. 3. The infrared receiving surface according to claim 1, wherein the infrared receiving surface is provided on the substrate in a cross grid pattern at a total of four places, and the one or more connecting portions are provided between the four infrared receiving surfaces. An infrared detecting element provided at the center or substantially at the center. 4. An infrared detecting element according to claim 1, wherein said plurality of infrared receiving surfaces are configured so that their polarities are alternately different.