JP3534281B2 - Detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a detection device for detecting a human body, and more particularly to a detection device which facilitates discrimination between a human body and a small animal. 2. Description of the Related Art FIG. 2 shows an outline of an example of a detection device. The illustrated detection device 1 includes a cover 2 for protecting a built-in detection unit, a chassis 3 for holding the detection unit, and a mounting board 4 for mounting the detection device 1 on a ceiling or a wall. FIG. 6 shows a detecting section 6 housed in the detecting device 1. The detection unit 6 is integrally attached to the frame 63 such that the detection element 61 and the concave mirror 65 face each other. Further, shafts 64 are provided on both sides of the frame 63, and the shafts 64 are rotatably held by holding members 62 fixed to the chassis 3. Then, the monitoring area can be set by rotating the frame 63 about the axis 64. The monitoring area of the detection device 1 will be described with reference to FIG. Since the viewing angle A of the monitoring area determined by the setting position of the detecting element 61 of the detecting unit 6 and the concave mirror 65 is constant, the width of the monitoring area differs when the monitoring area is set far and close. It will be. (A)
Indicates a case where the monitoring area is set far, and the monitoring range 7a at this time is widened. (B) shows a case where the monitoring area is set near, and the monitoring range 7b at this time becomes narrow. [0005] The detection device 1 determines the presence or absence of an intruder based on a change in the amount of infrared energy within the monitoring range. Then, as shown in FIG.
Even in the case of a monitoring area far from or a monitoring area near, since the detection element 61 and the concave mirror 65 are fixed so as to maintain a predetermined positional relationship, infrared rays incident from the monitoring area are focused on the concave mirror. The reflected light is always received by the detection element 61 at a fixed angle. Therefore, as shown in FIG. 7A, when the monitoring area is set far and the monitoring area 7a is wide, the ratio of the intruding object to the monitoring area 7a becomes small. That is, the ratio of the amount of infrared light generated from the intruding object to the amount of infrared light in the entire monitoring area is small.
Therefore, even if a small animal 71 such as a cat or a mouse enters the monitoring range 7a, it is not detected. On the other hand, as shown in FIG. 7B, when the monitoring area is set near and the monitoring area 7b is narrow, the ratio of the intruding object to the monitoring area 7b is the same in the monitoring area 7a. Of invaders. Therefore, the proportion of the small animal 71 in the monitoring area 7b also increases, and the difference from the proportion of the human in the monitoring area 7a decreases. That is, the small animals 71 in the monitoring range 7b
It becomes difficult to distinguish between the small animal 71 and the human in the monitoring range 7a, and the small animal 71 may be determined to be an intruder and falsely notified.
Therefore, an object of the present invention is to provide a detection device that can distinguish small animals from humans even when the setting of the monitoring area changes. A detection element fixedly installed for detecting infrared rays, and a monitoring area is set by rotating around the detection element, and infrared rays in the monitoring area are transmitted to the detection elements. Light condensing means for condensing light, wherein the light condensing means changes the size of the monitoring area in accordance with the rotation angle.
Equal to the ratio at which the detection output of the detection element changes.
The angle of incidence of the infrared rays on the detection element is made variable according to the angle of rotation so that the angle of incidence of the infrared rays becomes closer to the detection element surface as the monitoring area is farther from the detection device. A sensing device is provided. DETAILED DESCRIPTION OF THE INVENTION The present invention focuses on the fact that the output of a detection element changes in accordance with the angle of incidence of infrared rays on the detection element. Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows the outer shape of the detection device 1.
The illustrated detection device 1 includes a cover 2 for protecting the detection unit, a chassis 3 for holding the detection unit, and a mounting board 4 for mounting the detection device 1 on a ceiling or a wall. FIG. 1 shows a detecting section 5 housed in the detecting device 1. As shown in FIG. In the detection unit 5, the detection element 51 is fixedly installed on the chassis 3 by the detection element holder 52, and a concave mirror 55 (light collecting unit) is attached to the frame 54 so as to face the detection element 51. As the detection element 51, a dual-type pyroelectric element is used. The detection element is not limited to this as long as it can detect infrared rays. A shaft 56 is provided on both sides of the frame 54.
The shaft 56 is rotatably held by a frame holder 53 fixed to the chassis 3. In addition,
The detecting element 51 is arranged on the axis of the shaft 56. The configuration is not limited to this as long as the trajectory of the concave mirror 55 is concentric with the detection element 51 as a center.
Then, the monitoring area is set by rotating the concave mirror 55 about the axis 56 while keeping the distance from the detection element 51 constant. Here, the characteristics of the detection element 51 will be described with reference to FIG. The detection element 51 has an infrared detection surface 511. The output of the infrared ray incident on the detection element 51 is the maximum for the infrared ray R1 perpendicularly incident on the infrared ray detection surface 511. And the detection element 5 at this time
Let X be the output of 1 and let Y be the output when an infrared ray R2 having the same energy as the infrared ray R1 is incident on the infrared detection surface 511 at an angle of θ from the perpendicular. It has been found that: Y ≒ XCOSθ (1) FIG. 3 is a diagram showing the operating principle of the detection device 1 according to the present invention. The solid line indicates the incident path of infrared rays in the farthest monitoring range 7a monitored by the detection device 1. On the other hand, a dotted line indicates an incident path of infrared rays from the monitoring area 7b closer to the detection device 1 than the monitoring range 7a. The positional relationship between the concave mirror 55 and the detecting element 51 will be described. The concave mirror 55 and the detection element 51 are arranged so that the infrared light incident from the monitoring range 7a is incident on the detection element 51 from the concave mirror 55 almost perpendicularly. Note that the size of the monitoring area is determined by the viewing angle and the rotation angle of the concave mirror 55 and the distance between the detection device 1 and the floor.
When the detection device 1 is installed at a predetermined height, the monitoring range 7
Assuming that the area of “a” is “1”, the area of the monitoring area (monitoring range 7b) when the concave mirror 55 is rotated by the angle θ is “CO”.
The surface area, condensing angle, reflection angle, and the like of the concave mirror 55 are set so as to be “Sθ”. Next, the operation of the detection device 1 will be described. As described above, the farthest monitoring range 7 monitored by the detection device 1
a is set to monitor the infrared ray, the infrared ray emitted in the monitoring range 7 a
The light is incident almost perpendicularly to 51. To set the monitoring area from the monitoring range 7a to the monitoring range 7b, the concave mirror 5
5 is rotated counterclockwise about the shaft 56 by an angle θ from the position where the monitoring range 7a is monitored. At this time, axis 5
Since the detecting element 51 is arranged on the axis of No. 6, the concave mirror 55 rotates while maintaining a constant interval from the detecting element 51. As a result, as shown by the dotted line, the monitoring range 7b
Is incident on the infrared detection surface 551 at an angle θ from the vertical direction. Therefore, according to the characteristics of the detection element 51 described above, the output of the detection element 51 is assumed to be "1" when the small animal 71 enters the monitoring area 7a, and the same small animal 7 enters the monitoring area 7b.
The output for the intrusion of 1 is almost “COSθ”. That is, the output ratio of the detection element 51 to the same small animal in the monitoring range 7a and the monitoring range 7b is “1: COSθ”. Further, as described above, the ratio of the width of the monitoring range 7a to the width of the monitoring range 7b is set to be "1: COSθ". Therefore, the output ratio for the same intruder in the monitoring range 7a and the monitoring range 7b becomes equal to the ratio of the width of the monitoring range. This indicates that the ratio of the amount of infrared light due to the invading object to the amount of infrared light in the entire monitoring area is kept substantially constant even when the monitoring area changes. That is, as long as the intruder is the same, the output of the detection element 51 is the same regardless of the setting position of the monitoring area. Therefore, it is possible to reliably distinguish between a human and a small animal regardless of the setting position of the monitoring area. In this embodiment, the concave mirror 55 is used as the light condensing means.
However, it is needless to say that a Fresnel lens or another lens can be used as long as it can condense infrared rays on the detection element 51. Further, in the present embodiment, an example in which the present invention is used for a detection device used for human body detection is shown. . According to the present invention, the same is true regardless of whether the detection area is set far from the detection device or the detection area is set near the detection device. The detection output of the detection element with respect to the heat source that emits infrared rays can be made substantially constant. Therefore, the heat source can be distinguished regardless of the distance of the monitoring area.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a detection unit of a detection device according to the present invention. FIG. 2 is a diagram showing an outer shape of a detection device according to the present invention or a conventional detection device. FIG. FIG. 4 is an explanatory diagram of the characteristics of the detecting element. FIG. 5 is an explanatory diagram of the operation of the conventional detecting device. FIG. 6 is a configuration diagram of a detecting unit of the conventional detecting device. FIG. 7 is an explanatory diagram of a monitoring area. Description 1 Detector 2 Cover 3 Chassis 4 Mounting board 5 Detector 51 of detector according to the present invention Detector 511・ Infrared detecting surface 52 ・ ・ ・ Detecting element holder 53 ・ ・ ・ Frame holder 54 ・ ・ ・ Frame 55 ・ ・ ・ Concave mirror (condensing means) 56 ・ ・ ・ Axis 6 ・ ・ ・ Detection of conventional detector Part 61 Detection element 62 Holder 63 Frame 64 Shaft 65 Concave mirror (light collecting means) 7a: remote monitoring range 7b: near monitoring range

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01V 8/14 G01J 1/02 G01V 8/12 G08B 13/191

Claims (1)

(57) Claims 1. A fixedly installed detection element for detecting infrared rays, and a monitoring area is set by rotating around the detection element to detect the infrared rays in the monitoring area. Light condensing means for converging light on an element, wherein the light condensing means is provided in the monitoring area according to the angle of rotation
And the detection output of the detection element changes.
The angle of incidence of the infrared ray on the detection element is made variable so as to make the infrared ray incident on the detection element more vertically as the monitoring area is set farther. apparatus.