JPH0827337B2 - Directional detector for heat source - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat source direction detecting device, and more specifically, to detect the directionality of a heat source based on output signals from a plurality of pyroelectric elements. To a new device that does.

<Prior Art> Conventionally, as a device for detecting the presence or absence of a heat source, a pyroelectric element that generates an electric signal in response to a change in heat rays has been provided. More specifically, the pyroelectric element is mainly composed of a pyroelectric body made of a LiTaO ₃ single crystal, etc., and the magnitude of spontaneous polarization changes in response to temperature changes, and the rate of change of surface electrification is The electrification can be observed for a comparatively short time because it is smaller than the rate of change of spontaneous polarization. The temperature change of the pyroelectric body is caused by a change in the incident infrared ray amount, and moreover, the heat source such as the human body and the stove emits a considerable amount of infrared rays. As the total amount of infrared radiation emitted from the heat source within the field of view of the body changes, the pyroelectric body produces an electrical signal corresponding to the amount of infrared change.

Therefore, if the field of view of the pyroelectric body is made quite narrow, it is possible to generate an electrical signal associated with the movement of the heat source between the inside and the outside of the field of view.
The range in which the presence or absence of the heat source can be detected becomes narrow. On the contrary, if the field of view of the pyroelectric body is widened, the possibility that the heat source moves between the inside and the outside of the field of view decreases, and the detection accuracy of the presence or absence of the heat source decreases.

In order to solve such a problem, conventionally, a split mirror having a plurality of mirror surfaces is arranged at a position relatively close to the pyroelectric body, and the focus of each mirror surface is aligned with the incident surface of the pyroelectric body. In addition, there is provided a heat source presence / absence detection device in which the relative positional relationship between the split mirror and the pyroelectric body is set so that the field of view when viewed from the pyroelectric body through each mirror surface becomes discontinuous.

<Problems to be Solved by the Invention> In the heat-source presence / absence detection device having the above-described configuration, it is possible to detect the presence / absence of a heat source in a wide range as a whole, and the inside and outside of the field of view seen through each mirror surface. Increase the possibility of heat source movement between
The heat source presence / absence detection sensitivity can be improved.

However, in the pyroelectric body, since infrared rays guided from all mirror surfaces are incident and an electric signal is generated only when the total amount of incident infrared rays changes, it is based on the fact that the electric signal is generated. It is only possible to detect the presence of the heat source, and it is impossible to detect in which part of the total range that can be seen through the split mirror the heat source is present.

In order to solve such a problem, while narrowing the range in which the presence or absence of a heat source is detected by the pyroelectric body,
It is conceivable to increase the number of pyroelectric bodies so that the existence region of the heat source can be identified by monitoring which pyroelectric body generated the heat source detection signal.

However, if such a configuration is adopted, the number of pyroelectric bodies must be increased as the range in which the presence or absence of a heat source is to be detected becomes wider, and the configuration of the heat source detection device as a whole becomes complicated. There is a problem that it will end up.

More specifically, there is a strong demand for energy saving in recent years, and it is possible to illuminate only a truly necessary place in a large factory, office, or the like, or to perform conditioned air blowing of an air conditioner. The system is being considered. In such a system, as information for performing the above control, it is necessary not only whether or not a heat source such as a human body is present, but in which area the heat source is present, A heat source direction detecting device is essential as a device for obtaining such information.

However, as such a heat source direction detection device, only the one whose configuration is significantly complicated as described above is provided, and the configuration of the entire system incorporating the heat source direction detection device is also significantly complicated. There is a problem that it ends up.

<Object of the Invention> The present invention has been made in view of the above problems, and an object of the present invention is to provide a device for detecting the directionality of a heat source, the structure of which can be significantly simplified.

<Means for Solving Problems> A heat source direction detecting device of the present invention for achieving the above-mentioned object receives three heat rays radiated from a heat source and generates three heat source detection signals. However, they are displaced from each other by a predetermined distance in a predetermined direction, have a common field of view, and are arranged so that the irradiation state of the heat ray changes with different characteristics corresponding to the position of the heat source. In addition, it has a signal generating means for generating a heat source direction detection signal using the heat source detection signal output from each pyroelectric element as an input.

However, if three pyroelectric elements are arranged on a predetermined plane with respect to the splitting mirror for concentrating heat rays, and the arrangement positions of each pyroelectric element with respect to the focal point of each mirror surface of the split mirror for concentrating heat rays are different from each other. It may be provided, or has a slit member for restricting the field of view of each pyroelectric element, and is incident on each pyroelectric element in correspondence with the heat ray incident direction on each pyroelectric element. It may have a filter for changing the attenuation of heat rays, or the pyroelectric elements are arranged so that the heat ray incident surfaces of the pyroelectric elements are at different angles with respect to the heat source. It may be

<Operation> In the heat source direction detecting device having the above configuration, the three pyroelectric elements that receive the heat rays emitted from the heat source and generate the heat source detection signal have substantially the same field of view, and Since the irradiation state of the heat ray changes with different characteristics depending on the position of the heat source, the influence of the heat ray emitted from the heat source on each pyroelectric element is the same. The heat source detection signals generated by each pyroelectric element are the same when the heat sources move between the inside and the outside of the field of view of the pyroelectric element having substantially the same field of view. Or they will be different from each other.

Therefore, if the heat source detection signals output from the pyroelectric elements are supplied to the signal generating means, whether the heat source detection signals output from the pyroelectric elements are the same or different from each other (all are mutually different). It is possible to determine whether they are different or partially different), and it is possible to generate the direction detection signal of the heat source based on the determination result.

Then, three pyroelectric elements are arranged on a predetermined plane with respect to the splitting mirror for concentrating heat rays, and the arrangement positions of each pyroelectric element with respect to the focal point of each mirror surface of the split mirror for concentrating heat rays are different from each other. Even if it is provided, or it has a slit member for restricting the field of view by each pyroelectric element, and the heat ray incident on each pyroelectric element in correspondence with the heat ray incident direction on each pyroelectric element. Even if the pyroelectric element has a filter for changing the attenuation amount, the pyroelectric elements are arranged such that the heat ray incident surfaces of the pyroelectric elements have different angles with respect to the heat source. Even in such a case, the same effect as described above can be achieved.

<Example> Hereinafter, an example will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic view showing an embodiment of a heat source directionality detecting device of the present invention, and three pyroelectric elements (11) (12) (13)
Are arranged in close proximity to each other, a split mirror (2) for concentrating heat rays is arranged at a predetermined position, and further heat source detection from each pyroelectric element (11) (12) (13) It has a signal generator (3) which receives a signal and generates a directionality detection signal.

More specifically, each of the pyroelectric elements is made of LiTaO ₃ , and the split mirror (2) for concentrating heat rays is formed by integrating a plurality of mirror surfaces (21) (22) ... (2n). In this configuration, the focal points of the respective mirror surfaces coincide with each other, and the fields of view seen from the focal points through the respective mirror surfaces become discontinuous, which is a conventionally known configuration. Then, as shown in FIG. 2, the relative positions of the focal points with respect to the pyroelectric elements (11), (12) and (13) are set to be different from each other.

FIG. 3 is a block diagram showing an electrical configuration of the signal generating device (3), which includes amplification circuits (31a) (31b) (31c) for amplifying output signals from the pyroelectric elements and the amplification circuits. Waveform shaping circuit (32a) (32b) (32c) that generates a pulse signal with the width corresponding to the peak height by using the output signal of
And the pulse width detection circuits (33a) (33b) (33c) that generate the pulse width detection signal corresponding to the pulse width by inputting the output signal from each waveform shaping circuit and the output signal from each pulse width detection circuit. Level signal generation circuits (34a) (34b) (34c) that generate digital signals corresponding to three types of levels by comparing with two types of threshold values as inputs, and output signals from each level signal generation circuit as inputs The directivity detection signal generating section (35) including a microcomputer or the like, which identifies the combination state of the three types of level signals and generates the directionality detection signal corresponding to the identified combination state.

The operation of the heat source direction detecting device having the above configuration is as follows.

In the monitoring area (4) shown in FIG. 1, the heat source moves in an area centered on the line indicated by C, and among the mirror surfaces constituting the split mirror (2) for concentrating heat rays, the mirror surface corresponding to the above area. If the heat source moves between the inside and the outside of the visual field due to, the intensity of heat ray incident on each pyroelectric element (11) (12) (13) changes, so that each pyroelectric element (11) (12) (1)
From 3), a signal having a peak height corresponding to the change in the heat ray incident intensity is output (see FIG. 4A). In this case, each pyroelectric element (11) with respect to the focal position of the mirror surface
Since (12) and (13) are set as shown in FIG. 2, as shown by C in FIG. 2, the change amount of the heat ray incident intensity on the pyroelectric element (13) becomes small and other The change amount of the heat ray incident intensity with respect to the pyroelectric elements (11) and (12) becomes large.

Therefore, the output signals from each of the pyroelectric elements (11) (12) (13) are amplified by the amplifier circuits (31a) (31b) (31c) and supplied to the waveform shaping circuits (32a) (32b) (32c). By doing so, it is possible to obtain a pulse signal having the width corresponding to the peak height (the pulse heights are the same) (see FIG. 4B). That is, the pulse width corresponds to the magnitude of the change amount of the heat ray incident intensity.

Then, the pulse width detection circuit (33
By supplying a) (33b) and (33c), it is possible to obtain a pulse width detection signal corresponding to the pulse width, that is, the amount of change in the heat ray incident intensity, and each pulse width detection signal is supplied to the level signal generation circuit. By supplying the signals to (34a), (34b) and (34c), it is possible to obtain a digital signal corresponding to any of the three levels.

Further, by supplying each digital signal to the directionality detection signal generation section (35), the combination state of the digital signals is identified, and the directionality detection signal (the area (4) shown in FIG. 1) corresponding to the combination state is identified. Of these, a directionality detection signal indicating that the heat source is moving in a region centered on the line indicated by C can be output.

Therefore, based on this directionality detection signal, the direction in which the heat source is present can be identified, and lighting control, conditioned air blowing control of the air conditioner, etc. are performed based on the identification result, thereby saving energy. Can be achieved.

In the above description, only the case where the heat source exists in the area indicated by C in the area (4) in FIG. 1 has been described. However, when the heat source exists in the area indicated by A in the area (4) described above, As shown by A in FIG. 2, the change amount of the heat ray incident intensity on the pyroelectric element (11) becomes large and the change amount of the heat ray incident intensity on the other pyroelectric elements (12) (13) becomes moderate. Further, when the heat source exists in the area indicated by B in the area (4), as shown by B in FIG. 2, the change amount of the heat ray incident intensity with respect to the pyroelectric element (11) becomes large, Since the change amount of the heat ray incident intensity to the pyroelectric element (12) becomes medium and the change amount of the heat ray incident intensity to the pyroelectric element (13) becomes small, based on the combination of the level of the change amount of each heat ray incident intensity. It is possible to identify in which direction the heat source is present.

Further, the focal position of the mirror surface corresponding to the above areas A, B, C,
Since they coincide with each other on a predetermined circle (see the broken line in FIG. 2), in the case of a region different from the above-mentioned regions A, B, C, they have different focus positions. Then, since the change amount of the heat ray incident intensity with respect to each pyroelectric element (11) (12) (13) changes with the change of the focal position, the direction of the heat source is identified in the same manner as above. be able to.

FIG. 5 is a schematic view showing another embodiment. The difference from the above embodiment is that instead of the splitting mirror (2) for concentrating heat rays,
A filter (6) for attenuating heat rays is provided so as to be located between a point where a slit member (5) that divides the monitoring region discontinuously is provided and between each pyroelectric element (11) (12) (13). Only the points are different, and the configurations of other parts are the same.

More specifically, as the heat ray attenuation filter (6), as shown in FIG. 6, a three-pronged filter whose thickness is changed so that the heat ray attenuation amount increases toward the center is used. ing.

Therefore, also in the case of this embodiment, when the heat source moves between the inside and the outside of the field of view obtained by the slit member (5), the pyroelectric elements (11) (12) (13) receive the heat rays. Since the intensity change amount will be determined corresponding to the direction of the heat source, it is possible to detect the directionality of the heat source by identifying the combined state of the heat ray incident intensity change amount in the same manner as in the above embodiment. it can. Specifically, in the direction shown by arrow A in FIG. 6, the pyroelectric element (11)
Of the other pyroelectric elements (12) and (13) are low.
In the case of the direction indicated by arrow B, the pyroelectric element (1
1) The change level of the heat ray incident intensity is high and the pyroelectric element (1
The change amount level of the heat ray incident intensity of 2) is moderate, and the change amount level of the heat ray incident intensity of the pyroelectric element (13) becomes low. Further, when the direction is indicated by the arrow C, the pyroelectric element (1
1) The change level of the heat ray incident intensity is high and the pyroelectric element (1
2) The heat ray incident intensity change level of 2) is low, and the pyroelectric element (1
The heat ray incident intensity change level of 3) becomes medium. Further, even when the directions change with respect to the pyroelectric elements (12) and (13), the directivity of the heat source can be detected in the same manner.

FIG. 7 is a schematic view of a main part showing still another embodiment,
The difference from the embodiment of FIG. 6 is that each pyroelectric element (11) (12)
It is only the point that (13) is tilted in the priority monitoring direction and the heat ray incident angle with respect to each pyroelectric element (11) (12) (13) is changed according to the direction of the heat source. The structure of the part is the same.

Therefore, also in the case of this embodiment, when the heat source moves between the inside and the outside of the field of view obtained by the slit member (5), the pyroelectric elements (11) (12) (13) receive the heat rays. Since the intensity change amount will be determined corresponding to the direction of the heat source, it is possible to detect the directionality of the heat source by identifying the combined state of the heat ray incident intensity change amount in the same manner as in the above embodiment. it can. Specifically, in the direction shown by arrow A in FIG. 7, the pyroelectric element (11)
Of the other pyroelectric elements (12) and (13) are low.
In the case of the direction indicated by arrow B, the pyroelectric element (1
1) The change level of the heat ray incident intensity of (12) is medium, and the change amount of the heat ray incident intensity of the pyroelectric element (13) becomes zero.
Further, in the direction indicated by the arrow C, the level of change in the heat ray incident intensity of the pyroelectric elements (11) and (13) is medium, and the amount of change in the heat ray incident intensity of the pyroelectric element (12) becomes zero. Become.
Further, even when the directions change with respect to the pyroelectric elements (12) and (13), the directivity of the heat source can be detected in the same manner.

Note that the present invention is not limited to the above-described embodiments. For example, it is possible to detect a relatively rough directionality with only two pyroelectric elements, and four or more pyroelectric elements. As a result, it is possible to detect the directionality more accurately as described above. Further, in the embodiment of FIG. 1, a slit member is used instead of the split mirror for concentrating the heat rays.
In the embodiment shown in FIG. 7 and FIG. 7, a split mirror for concentrating heat rays can be used in place of the slit member, and various design changes can be made without departing from the scope of the invention. is there.

<Effects of the Invention> As described above, according to the present invention, a plurality of pyroelectric elements are arranged close to each other, and the state of incidence of heat rays on each pyroelectric element changes in accordance with the direction of the heat source. In addition, the direction of the heat source is identified based on the combination of the output signals from each pyroelectric element.
With a relatively simple configuration in which a relatively small number of pyroelectric elements are incorporated into a unit, the unique effect of being able to detect the directionality of the heat source in a wide range is obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a heat source direction detecting device of the present invention, FIG. 2 is a view showing a relationship between a focal point of a splitting mirror for concentrating heat rays and each pyroelectric element, and FIG. 3 is a signal generation. FIG. 4 is a block diagram showing an electrical configuration of the apparatus, FIG. 4 is a diagram showing signal waveforms of respective parts of the block diagram of FIG. 3, FIG. 5 is a schematic diagram showing another embodiment, and FIG. FIG. 7 is a schematic view of a main part, and FIG. 7 is a schematic view of a main part showing still another embodiment. (2) …… Split mirror for concentrating heat rays, (3) …… Signal generator, (5) …… Slit member, (6) …… Filter for attenuating heat rays, (11) (12) (13) …… Pyroelectric element

 ─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-63-253217 (JP, A) JP-A-54-40989 (JP, A) JP-A-60-218081 (JP, A) JP-A-49- 123061 (JP, A) JP 62-75307 (JP, A) Actually developed 63-92486 (JP, U)

Claims (4)

[Claims] 1. Three pyroelectric elements which receive a heat ray radiated from a heat source and generate a heat source detection signal are displaced from each other by a predetermined distance in a predetermined direction and have a field of view in which a common region exists. In addition, the irradiation state of the heat ray is arranged so as to change with different characteristics corresponding to the position of the heat source, and the direction detection signal of the heat source is input with the heat source detection signal output from each pyroelectric element as an input. A heat source directivity detecting device having a signal generating means for generating the heat source. 2. Three pyroelectric elements are arranged on a predetermined plane with respect to the splitting mirror for concentrating heat rays, and the arrangement position of each pyroelectric element with respect to the focal point of each mirror surface of the split mirror for concentrating heat rays is set. The device for detecting the directionality of a heat source according to claim 1, which is different from each other. 3. A filter having slit members for restricting the visual field of each pyroelectric element and changing the attenuation of the heat rays incident on each pyroelectric element in correspondence with the direction of incidence of heat rays on each pyroelectric element. The heat source directionality detection device according to claim 1, further comprising: 4. The heat source directionality detection device according to claim 1, wherein the pyroelectric elements are arranged such that the heat ray incident surfaces of the pyroelectric elements are at mutually different angles with respect to the heat source. .