JPH057675B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an infrared detection device for a moving body.

2. Description of the Related Art Conventionally, devices have been known that detect heat rays emitted from a human body, that is, infrared rays, for the purpose of crime prevention or the like. In other words, all matter above absolute zero emits radiant energy (heat rays).
The human body is no exception in that it emits heat rays, and this is something that can be utilized. In this case, the radiation wavelength emitted from the human body is approximately 10 μm.
A common method is to reflect the infrared rays from a reflecting mirror having a paraboloid of rotation and focus the light on a pyroelectric sensor. For example, as shown in FIGS. 1 and 2, a pyroelectric sensor 1 is mounted on a PC board 2, and a reflector 4 formed by cutting a paraboloid of revolution 3 in half along a plane containing the rotation axis is provided. The present applicant has already proposed a sensor in which the detection surface 5 of the electric sensor 1 is placed at the focal point F of the paraboloid of revolution 3. According to such a reflecting mirror 4, a linearly sharp beam, that is, a beam with a narrow spread width can be obtained, and a device that monitors and warns when a human body or the like crosses this detection beam can be easily realized. Also, pyroelectric sensor 1
Since it is directly attached to the PC board 2, there is an advantage that the detection signal amplification circuit and reading circuit can be configured on the same board.

In the reflecting mirror 4 having the paraboloid of revolution 3, all infrared rays parallel to the axis are reflected toward the focal point F and condensed. However, as shown in FIG. 3, the pyroelectric sensor 1 has a viewing angle θ ₀ with respect to the detection direction. Therefore, in contrast to the pyroelectric sensor 1 which performs surface detection using the detection surface 5, the entire surface of the reflector 4 is not effectively utilized, _and as shown in FIG. is part of. Furthermore, the effective viewing angle θ ₀
Even if the angle between the detection direction φ of the pyroelectric sensor 1 and _the detection direction _{φ is θ}
It has the relationship W _T ^COS θ _X. For example, if _θ
It will only contribute.

This will be discussed using an example of a circuit for generating a human body detection signal shown in FIG. First, the pyroelectric sensor 1 is designed to specifically detect heat rays (infrared rays) at a temperature of around 35° C. of the human body 6, and normally the potential of the source S is determined by sensing the background temperature. Then, when the human body 6 crosses the detection beam, the pyroelectric sensor 1 detects the human body temperature, that is, infrared rays, and its source potential changes by increasing (if the human body temperature is higher than the background temperature) or decreasing. This variation is amplified by the operational amplifier 7 to obtain a human body detection signal from the output terminal T _OUT . However, in this case, if the infrared rays from the human body 6 are gradually detected at the end of the reflecting mirror 4, the source potential V _S will fluctuate slowly, and a sufficient detection amplitude may not be obtained. Furthermore, the pyroelectric sensor 1 detects points other than the center point of the detection surface 5. That is, ideally, the aperture area of the reflecting mirror 4 should provide a beam that extends in a straight line, but because of the detection area, the beam spreads at a certain angle. Therefore, although the portion of the reflecting mirror 4 outside the effective range E _e hardly contributes to focusing infrared rays in the main direction, it acts on the portion corresponding to the spread of the beam in this oblique direction. When the beam expands, a human body can be detected in this expanded area.

This situation is the same even when a plurality of pyroelectric sensors are provided to detect infrared rays emitted from a human body, etc., and the direction of movement of the human body, etc. is also detected. That is, Special Publication No. 44-29615,
This is disclosed in JP-A-54-96088, JP-A-55-66091, and the like. Specifically, the sixth
As shown in the figure, two sets of reflectors 4A, 4B and pyroelectric sensors 1A, 1B are provided along the direction of movement of the human body 6, and the human body 6 crosses the detection beam 8A and focuses on each detection beam 8A, 8B. Electric sensor 1A
If it is detected by the pyroelectric sensor 1B after being detected by the detection beam 8B, it is detected that the human body 6 has moved from left to right, and the detection beam 8B is detected by the pyroelectric sensor 1B.
If it crosses R and 8A in this order, it is detected that it has moved from right to left. In this case, the detection beam 8 monitored by each pyroelectric sensor 1A, 1B
It is considered that A and 8B should not overlap (intersect) each other. That is, the human body 6 enters the detection beam 8A of the pyroelectric sensor 1A, exits the detection beam 8A, and then enters the detection beam 8A of the pyroelectric sensor 1A.
It is set to enter the detection beam 8B of B. For this reason, the two pyroelectric sensors 1A and 1B are sufficiently far apart, or the detection beam 8
A and 8B must be very sharp. However, in the former method, in order to integrate the detection devices such as the pyroelectric sensors 1A and 1B, it is necessary to have a wide width, which becomes an obstacle to miniaturization. Furthermore, even with the latter method, it has conventionally been necessary to use a reflecting mirror that is larger than the detection surface of the pyroelectric sensor (for example, as shown in Figure 1 of Japanese Patent Publication No. 44-29615).
After all, it lacks miniaturization and economic efficiency.

The present invention has been made in view of these points, and an object of the present invention is to provide an infrared detection device for a moving object that increases the directivity of a detection beam, has clear boundaries, is small and inexpensive, and contributes to reliable detection. It is something to do.

The present invention takes into account the viewing angle of the pyroelectric sensor that detects a surface, and cuts both ends of the reflector around the effective range with a plane perpendicular to the direction in which the movement of the object to be detected is detected, resulting in a simple configuration and directivity. It is designed to increase the detection capability by increasing the sensitivity and clarifying the boundaries of the detection beam.

A first embodiment of the present invention will be described based on FIGS. 7 to 10. In this embodiment, a pyroelectric sensor 12 is mounted on a PC board and a detection surface 11 is arranged at a focal point F position of a paraboloid of revolution 10 of a reflecting mirror 9 to perform surface detection.
This device adopts the basic configuration provided in No. 3, but is characterized in that both ends of the reflecting mirror 9 have cut surfaces 15 cut in a plane perpendicular to the movement detection direction of the human body 14, which is the object to be detected. . This cut surface 14
As shown in Fig. 10, the position is basically the position where the part outside the effective range E _e of the reflecting mirror 9 is removed, but even within this effective range E _e , the opening length in the left and right direction is The detection beam 16 is set at a position where the length is shortened and the detection beam 16 is made as thin as possible.

With this configuration, the reflecting mirror 9 with both ends cut off reduces the portion of the detection beam with low sensitivity, making the boundary of the detection beam 16 clear and increasing the directivity. Therefore, when the human body 14 crosses the end 16L or 16R of the detection beam 16, the infrared radiation received by the pyroelectric sensor 12 will fluctuate greatly. That is, considering FIG. 5, the source output of the pyroelectric sensor 12 is the source potential V _S
Since the human body detection signal is obtained by extracting and amplifying the temporal change dV _S /dt, if the ends 16L and 16R of the detection beam 16 are clear as in this embodiment, it is possible to cross them. The signal obtained by . Therefore, a detection device capable of monitoring a long distance without increasing the gain of the operational amplifier 7 can be obtained. Furthermore, the device becomes smaller, and the reflector 9 itself is advantageous in terms of cost.

Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment is applied to a detection device that also has the ability to detect the direction of movement shown in FIG. The pyroelectric sensors 12A, 1 are arranged side by side.
2B and the reflecting mirrors 9A and 9B shown in FIGS. 8 to 10 are used.

According to such a configuration, similar to the above embodiment,
The detection beam 16 is based on the shape of the reflecting mirrors 9A and 9B.
Since the directivity of A and 16B is increased and sharpened, and the edges 16AL, 16AR, 16BL, and 16BR are clear, the distance between the pyroelectric sensors 12A and 12B is narrowed, and the device is made smaller and cheaper. be able to. Then, reliable direction detection can be performed.

Next, a third embodiment of the present invention will be explained with reference to FIGS. 12 to 14. This embodiment basically uses pyroelectric sensors 12A, 12B and a reflector 9 having the structures shown in FIGS. 8 to 10, similar to the second embodiment.
A and 9B are arranged side by side, but the detection beams 16A and 16B for the respective pyroelectric sensors 12A and 12B have an overlapping region 17. Here, these detection beams 16A, 16
B is the end portions 16AL, 16BL, 16AR, 16
The BRs are set to be parallel to each other.
Further, detection areas D _A and D _B by the pyroelectric sensors 12A and 12B are set in an area crossing the overlapping area 17 (that is, in front of the line L).

Furthermore, the detection signals of the pyroelectric sensors 12A and 12B are converted into pulse signals S _A and S
S _B and is set to be input to the signal order identification circuit 20. The output signal in direction 1 (left to right) from this signal order identification circuit 20 is input to the direction 1 display circuit 21A, and the output signal in direction 2 (right to left) is input to the direction 2 display circuit 21B. There is. Further, both output signals from the signal order identification circuit 20 are input to an AND gate 22,
The output signal from the AND gate 14 is inputted to the signal order identification circuit 20 via a signal acceptance stop timer 23 as a signal acceptance stop signal.

In such a configuration, consider a case where the human body 14 walks from left to right (in FIG. 12). First, the human body 14 is located at the end 16AL of the detection beam 16A.
Based on the infrared rays from the human body 14, the pyroelectric sensor 1 detects that the person has entered the detection area D _A by crossing the
Detected by 2A. Then, when walking further to the right, the pyroelectric sensor 12B detects that it has reached the end 16BL of the detection beam 16B,
The signal order identification circuit 20 detects the order of these detection signals and determines that the moving direction of the human body 14 is direction 1 (from left to right). If you walk further to the right, you will enter the detection area D _B , so when you know the walking direction in the detection area D _A (i.e., overlap area 1
7), the signal reception stop timer 23
The detection operation is stopped for a certain period of time to prevent malfunction. On the other hand, the direction 1 display circuit 21A displays the output signal of the signal order identification circuit 20 to indicate that the movement of the human body 14 from left to right has been detected, for example, if this detection device is installed at a store. A voice message saying "I'm annoyed" is displayed. Similarly, if movement in the opposite direction from right to left is detected, the direction 2 display circuit 13B displays a message to that effect, for example, a voice message such as "Thank you for your continued support."

Therefore, especially according to this embodiment, although the pyroelectric sensors 12A and 12B are arranged side by side, their detection beams 16A and 16B have an overlapping region 17, so that when the devices are integrated, the pyroelectric sensors 12
It is possible to reduce the size by shortening the distance between A and 12B. At this time, since the left and right ends 16AL, 16BL, 16AR, and 16BR of the detection beams 16A and 16B are respectively spread in parallel, and the detection areas D _A and D _B are set in areas that cross the overlapping area 17, Since the detection order is not ambiguous and the detection beams 16A and 16B do not need to be made sharp, the reflecting mirrors 9A and 9B do not need to be large, and from this point of view as well, they can be miniaturized. Furthermore, since the two detection areas D _A and D _B are spread out, whichever direction is detected, it can be detected early and the direction can be accurately reported. At this time, since both ends of the reflecting mirrors 9A and 9B are cut, the boundary line between the detection beams 16A and 16B becomes clear, so even if the distance between the two pyroelectric sensors 12A and 12B is brought closer, the detection direction order can be maintained. The information is not ambiguous, and malfunction prevention can be ensured while reducing the size.

The application of this device is not limited to detecting the human body 14 at stores, escalator entrances, etc., but can also be used, for example, by installing it at parking lot entrances and exits to detect the entry and exit of cars.

The present invention is simple, compact, and inexpensive because it is equipped with a reflecting mirror in which both ends of a paraboloid of rotation are cut by a plane perpendicular to the movement detection direction of the detected object for the pyroelectric sensor that detects a surface as described above. In addition, by providing multiple such pyroelectric sensors and reflectors, it is possible to increase the directivity of the detection beam and clarify its boundaries, thereby improving the detection ability. It is possible to perform reliable direction detection, and in this case, the detection beam has an overlapping area, the detection beam ends are made parallel, and the detection area is also set to a predetermined area, so it is possible to achieve further miniaturization. It is capable of high-sensitivity detection.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a conventional example, Fig. 2 is a vertical side view, Fig. 3 is an explanatory drawing, Fig. 4 is a front view, Fig. 5 is a circuit diagram, Fig. 6 is an optical explanatory drawing, 7 is an optical explanatory diagram showing the first embodiment of the present invention, FIG. 8 is a front view, FIG. 9 is a side view thereof, FIG. 10 is an explanatory diagram, and FIG. 11 is a second embodiment of the present invention. FIG. 12 is an optical explanatory diagram showing a third embodiment of the present invention, FIG. 13 is a block diagram, and FIG. 14 is an optical explanatory diagram showing an embodiment.
Figures a and b are operational waveform diagrams. 9... Reflector, 10... Paraboloid of rotation, 11...
Detection surface, 12...Pyroelectric sensor, 14...Human body (detected object), 16...Detection beam, 17...Overlapping area, D _A to D _B ...Detection area.

Claims (1)

[Scope of Claims] 1. A moving body that detects the detected object by being equipped with a pyroelectric sensor that detects infrared rays emitted from a moving detected object such as a human body, and a reflector that focuses the light on the pyroelectric sensor. In this infrared detection device, the detection surface is placed at the focal position of the pyroelectric sensor that detects the surface, whereas both ends of the paraboloid of revolution are perpendicular to the movement detection direction of the detected object, and the viewing angle of the pyroelectric sensor is 1. An infrared detection device for a moving object, characterized in that a reflecting mirror is cut within an effective range corresponding to the above. 2. The detected object is equipped with a plurality of pyroelectric sensors that detect infrared rays emitted from a moving detected object such as a human body, and a plurality of reflectors that focus the light on the pyroelectric sensor along the moving direction of the detected object. In an infrared detection device for a moving object, the detection surface is placed at the focal position and the pyroelectric sensor detects the surface, whereas both ends of the paraboloid of revolution are perpendicular to the movement detection direction of the object to be detected. An infrared detection device for a moving object, characterized by having a reflecting mirror cut within an effective range corresponding to the viewing angle of an electric sensor. 3 The detected object is equipped with a plurality of pyroelectric sensors that detect infrared rays emitted from a moving detected object such as a human body, and a plurality of reflectors that focus the light on the pyroelectric sensor along the moving direction of the detected object. In an infrared detection device for a moving object, the detection surface is placed at the focal position and the pyroelectric sensor detects the surface, whereas both ends of the paraboloid of revolution are perpendicular to the movement detection direction of the object to be detected. A reflector cut within an effective range corresponding to the viewing angle of the pyroelectric sensor is provided, and the detection beams for each of the pyroelectric sensors are arranged in order so that they overlap each other and the ends of the detection beams are substantially parallel to each other. An infrared detection device for a mobile body, characterized in that the detection area of each pyroelectric sensor is set in an area that crosses the overlapping area of these detection beams.