JPS6089784A - Body detector - Google Patents

Abstract

PURPOSE:To detect a body in a specific area securely by outputting an alarm signal when the distance measured by detecting the reflection of light or infrared ray is less than specific limit distance. CONSTITUTION:A nearly planar alarm area is set along the external surface of a window 2 with four detection areas E1-E4 having limit distances determined by window end surfaces. A radiation source 6 which radiates light or infrared ray emits pulse light by a driving circuit 7 and the light is collimated by a collimator lens 8 into a nearly parallel beam. If there is a reflecting body M present in the traveling direction of the radiation beam, part of the reflected light is converged by a condenser lens 9, and is made incident to a couple of photodetecting elements 10 a and 10b. The ratio of the quantities of incident light depends upon the distance between a sensor and the reflecting body. Amplification outputs of circuits 11a and 11b are supplied to a dividing circuit 12 to calculate their ratio, and a threshold decision switch circuit 13 operates according to the value to generates an alarm output.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an object detection device that detects an object such as a human body using reflected light or infrared light.

(Background technology) Conventional devices for detecting intruders through openings in buildings, such as windows, did not have a distance limiting function. There was a risk of malfunctions due to detection of small animals or the effects of sunlight reflection on the ground.

(Object of the Invention) The present invention has been made in view of the above points, and its purpose is to provide an object detection device that can reliably detect only objects existing within a predetermined detection area. .

(Disclosure of the Invention) The present invention will be explained below based on a height example. Fig. 1 shows one embodiment of the present invention, and shows the detection area of a wall-side security sensor 1 installed on the outer surface of a window.

In this figure, along the outer surface of the window 2, four detection areas E1 to E4 with the end surface of the window at a limited distance of 7 are set as a rectangular viewing area. In addition, in the figure, 3 indicates the ground and 41d indicates the wall surface.

FIG. 2 is a diagram schematically showing one of the four distance measuring devices included in the sensor 1 shown in FIG.

Hereinafter, the operation of the distance measuring device 5 will be explained with reference to FIG.

A radiation source 6 (e.g. a near-infrared light emitting diode) emitting light or infrared radiation emits pulses (by means of a drive circuit 7);
Collimated into 11 i) rows of beams by a collimator lens of °8. If there is a reflecting object M in the traveling direction of the radiation beam, a part of the reflected light is focused by the lens 9 and enters the light receiving element pair 101, IO2, but at that time, each of the light receiving elements 102.10b The ratio of γ(ratio) of the incident light ■d depends on the distance 1iJ between Sen → V and the reflecting object (see Figure 3). Therefore, increase [11 circuits + 1a,
The output increased [1] by Ilb is ratioed by the divider circuit 12, and if the value is greater than the value determined by the preset limited distance, @value open/separate nwitch times 1i8
13 is 'ii! ＋Create and output. Therefore, anti-M and I objects beyond a limited distance (for example, small ribs near the ground)
It doesn't work in some cases.

This distance measuring device fi'45 11161 sets one detection area E. Therefore, by incorporating four distance measuring devices 5, for example, as shown in FIG. Snow 1 is formed.

In this embodiment, an optical system that performs the distance measurement method as shown in FIG. A method using a position detection diode, a method using a photodiode array, etc. may be used.
Further, it goes without saying that the present invention is not applied only to detecting an object entering through an opening as in the above embodiment.

(Effects of the Invention) Since the present invention is made as described above, it has the following effects.

- Since it has a distance bt limiting function, the reliability of detecting objects such as intruders is improved.

■Limited distance ^IC can be set arbitrarily: (An Ei-shaped detection area can be set.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram showing one embodiment of the present invention.
is a front view, tbl is a cross-sectional view, FIG. 2 is a schematic diagram showing an example of the distance measuring device f4 used in the same, and FIG. 3 is a characteristic diagram showing the ratio of received light output to reflection distance. Fig. 1 (a), b Fig. 3 J2 @ Mukuhoko 0se〉 Sukara chu large portrait

Claims (1)

[Claims] 111) A plurality of distance measuring optical systems that measure the distance to a reflective object by detecting reflected infrared light, and a measurement value of at least one of the distance measuring optical systems is within a predetermined limited distance. An object detection device consisting of a detection circuit that outputs an alarm signal at certain times.