JPH08315266A - Trespasser detecting device - Google Patents

Abstract

PURPOSE: To reduce the overall size of a trespasser detecting device which detects the presence of a trespasser with infrared-ray energy emitted by the body of the trespasser. CONSTITUTION: This trespasser detecting device is provided with an infrared detecting element 2 which has its photodetecting surface at the focus position of a parabolic mirror 1 and also provided with a dish-shaped reflecting mirror 11 which is arranged the outer circumference of the detecting element 2 opposedly to the parabolic mirror 1. The visual field of the reflecting mirror 11 sensed by the detecting element 2 through the parabolic mirror 1 faces the outer circumferential area of the parabolic mirror 1. The reflecting mirror 11 is composed of plural divisional plane mirrors formed out of planes containing straight lines forming ridges and straight lines forming valleys that extend radially from the optical axis of the parabolic mirror 1 as their center. The tilt angles of the divisional plane mirrors to the optical axis of the parabolic mirror 1 are set so that its visual field is not intercepted by the adjacent divisional plane mirrors. And, the parabolic mirror 1 is fixed to the tip edge of an infrared-ray transmission window 4 in a conic slanting surface shape surrounding the peripheral edge of the fitting base 12 for the detecting element 2 and reflecting mirror 11, thus constituting the trespasser detecting device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system of an apparatus for detecting the presence of infrared energy emitted from an intruder's body.

[0002]

2. Description of the Related Art A so-called passive infrared intruder detecting device using an element for detecting infrared energy emitted from an object includes infrared energy emitted from a background object within the detection range and infrared energy emitted from an intruder. The intruder is detected and the alarm signal is issued by comparing and identifying the levels. In this type of device, a parabolic mirror or an assembly of split parabolic mirrors is used as an optical system to give directivity to the detection range. The detection range that can be covered by a single device is one that only has a spread corresponding to the viewing angle range of the infrared detection element, or a solid angle (maximum 2π steradian) that has a predetermined direction and spread. There was something to do (hereinafter referred to as the round alert type). A device using an optical system for realizing a round alert type detection range such as the latter is disclosed in Japanese Utility Model Publication No. 4-18075.

A conventional technique will be described with reference to FIGS. 3 and 4. FIG. 3 is a partial cross-sectional view showing a part of the conventional intruder detection device 10 by cutting out. FIG. 4 is an explanatory diagram of a reflecting mirror used in the intruder detection device 10. In FIG. 3, a printed wiring board 6 is mounted at the center inside the circular tray-shaped base 5. The infrared detecting element 2 is mounted on the printed wiring board 6 while being held by the holding mechanism 8. Further, in the circular tray-shaped base 5, a conical reflecting mirror 3 is provided on the outer circumference of the infrared detecting element 2. An infrared transmitting window 4 having a conical slope shape is fitted and attached to the peripheral portion of the circular tray-shaped base 5, and the parabolic mirror 1 has its focus at the front end of the infrared transmitting window 4. It is mounted so that it is located on the active surface of the. The tilt angle of the reflecting mirror 3 is set such that the visual field L of the reflecting mirror 3 passes outside the parabolic mirror 1 and also through the infrared transmitting window 4.

FIG. 4 (a) is an external view of a conical reflecting mirror 3 composed of an assembly of split plane mirrors having such an inclination. That is, by arranging the conical reflecting mirror 3 so as to face the parabolic mirror 1, the field of view of the reflecting mirror 3 sensed by the infrared detecting element 2 through the parabolic mirror 1 is the parabolic mirror 1. By facing the outer peripheral area of the object mirror 1, a solid angle field of view toward the parabolic mirror 1 is set, and a round vigilant type intrusion with a detection range of 360 degrees around the detection device is set. Person detection device was realized. FIG. 4B is a diagram illustrating only one divided surface of the conical reflecting mirror 3. The shape of the split plane mirror is long in the direction that extends radially around the infrared detection element, and the tilt angle of this split plane mirror with respect to the optical axis of the parabolic mirror is tilted in the longitudinal direction of the split plane mirror.

[0005]

In the conventional round-warning type intruder detection device, since the shape of the reflecting mirror arranged facing the parabolic mirror is conical, the light of the parabolic mirror is There is a problem that the height of the reflecting mirror in the axial direction becomes large, and the entire apparatus becomes large accordingly.
In FIG. 4B, the shape of the split plane mirror is long in the direction that extends radially around the infrared detection element, and the tilt angle of this split plane mirror with respect to the optical axis of the parabolic mirror is the longitudinal direction of the split plane mirror. Since it was tilted to, the height h of the reflecting mirror in the optical axis direction of the parabolic mirror was inevitably increased. Since the reflecting mirror, which is an assembly of the split plane mirrors having such an inclination, is built in the intruder detection device 10 of FIG. 3, the height d of the circular tray-shaped base 5 becomes large, and the entire device becomes large. It had become. Further, when mounting the infrared detection element 2 on the printed wiring board 6, the printed wiring board 6 is not conical, so that the infrared detection element 2 is provided with a holding mechanism 8 such as an element holder near the apex of the conical reflecting mirror 3. Must be held by using the holding mechanism and
The fixing mechanism was complicated. Furthermore, the distance between the infrared detection element 2 that outputs a weak signal and the printed wiring board 6 is increased by the amount of the holding mechanism 8, and the infrared detection element 2
The conductive lead 9 was lengthened and was easily affected by noise from the surroundings.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention has a dish-shaped reflecting mirror arranged to face a parabolic mirror on the outer periphery of an infrared detecting element directly attached to a printed wiring board. Is. The reflecting mirror is an assembly of a plurality of split plane mirrors having a field of view extending radially around the optical axis of the parabolic mirror, and the tilt angle of each split plane mirror with respect to the optical axis of the parabolic mirror is The split plane mirror has a structure in which the angle of view is set so that the field of view is not obstructed.

[0007]

According to the above structure, since the reflector around the infrared detecting element, which is composed of the split plane mirrors having different tilt angles, has a dish shape as a whole, the reflector in the optical axis direction of the parabolic mirror is The height is low, and the holding mechanism for the detection element, which has been necessary in the past, is no longer needed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partial cutaway view showing a part of an intruder detecting device 20 of the present invention. In this figure, parts different from the conventional intruder detection apparatus 10 are a dish-shaped reflecting mirror 11 (conventionally conical reflecting mirror 3) and a circular tray-shaped base 12 (conventional circular tray-shaped base). 5, the height of the base is different [D <d]). The same parts as in the past are designated by the same reference numerals. In this figure, in order to explain the basic structure of the dish-shaped reflecting mirror used in the present invention in an easy-to-understand manner, the split plane mirrors are arranged in only two directions (when viewed toward the figure, the front direction and the right direction of the infrared detection element 2). It is placed only in). A printed wiring board 6 on which the infrared detection element 2 is directly mounted is attached to the center of the inside of the circular tray-shaped base 12. The printed wiring board 6 is mounted with an electric circuit (not shown) for instructing to output that an intruder is in the detection range in response to a signal from the infrared detection element 2. On the printed wiring board 6 on which the infrared detecting element 2 is mounted, the plane mirror 1 is provided around the infrared detecting element 2.
1 is provided. The split plane mirror 11a located in the front direction of the infrared detection element 2 is arranged with an inclination angle with respect to the optical axis of the parabolic mirror 1 facing the front surface of the infrared detection element 2 with a space. . The tilt angle of the split plane mirror 11a is set such that the field of view L of the split plane mirror 11a passes outside the parabolic mirror 1 and also through the infrared transmission window 4. As viewed in the figure, the inclination angle of the plane mirror 11b located on the right side of the infrared detecting element 2 is such that the field of view of the reflecting mirror passes through the outside of the parabolic mirror 1 and also through the infrared transmitting window 4. The angle is set.

FIG. 2 is an explanatory view of a reflecting mirror used in the intruder detecting device 20 of the present invention. FIG. 2A is an external view of a dish-shaped reflecting mirror composed of an assembly of split plane mirrors having an inclination as described with reference to FIG. This reflecting mirror is composed of a plurality of split plane mirrors formed by a plane including a straight line forming a ridge extending parabolically from the center and a straight line forming a valley. This reflector is used as the intruder detection device 2 of the present invention.
The infrared detection element 2 of No. 0 is directly attached to the printed wiring board 6 so as to be fitted into the cylindrical portion in the center of the reflecting mirror. The tilt angle of each of the split plane mirrors with respect to the optical axis of the parabolic mirror 1 is set to an angle within a range where the field of view is not obstructed by the neighboring split plane mirrors. Further, since the tilt angle of the split plane mirror is set so that the field of view of the reflecting mirror, which is detected by the infrared detecting element 2 through the parabolic mirror 1, faces the outer peripheral region of the parabolic mirror 1, the parabolic surface It is possible to realize a round alert type intruder detection device that establishes a three-dimensional field of view toward the mirror 1 and has a detection range of 360 degrees around the detection device. Further, a convex lens 7 having a diameter substantially the same as the outer diameter of the infrared detecting element 2 is fitted to the central optical axis portion of the parabolic mirror 1. The focal point of the convex lens 7 is assumed to be connected to the active surface of the infrared detecting element 2, whereby a detection zone M (central monitoring line) is established in the optical axis direction of the parabolic mirror 1. By establishing this central monitoring line, more reliable intruder detection is possible.

FIG. 2B is a view showing only one divided surface of the dish-shaped reflecting mirror 11. The shape of the split plane mirror is long in the direction that extends radially around the infrared detection element. Further, since the tilt angle of the split plane mirror with respect to the optical axis of the parabolic mirror is tilted in the lateral direction of the split plane mirror, the height H of the reflecting mirror in the optical axis direction of the parabolic mirror becomes small. Since the reflecting mirror 11, which is an assembly of divided plane mirrors having such an inclination, is built in the intruder detection device 20 of FIG. 1, the height D of the circular tray-shaped base 12 is accordingly reduced, and the entire device is reduced. It got smaller.

[0011]

As described above, according to the present invention, in the round-warning type intruder detection device, by making the reflecting mirror arranged facing the parabolic mirror into a dish shape, the entire detection device is compact. Was transformed. And since the infrared detection element is directly attached to the printed wiring board, the holding mechanism is unnecessary,
The parts cost and assembly cost were reduced. In addition, the length of the conductive lead part of the infrared detection element is shortened because the holding mechanism that holds the infrared detection element as in the past has become unnecessary, and it is less susceptible to noise from the surroundings, and intruder detection is possible. It also led to the improvement of device reliability.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a part of an intruder detection device of the present invention by cutting away.

FIG. 2 is an explanatory diagram of a reflecting mirror used in the intruder detection device of the present invention.

FIG. 3 is a partial cross-sectional view showing a conventional intruder detection device with a part cut away.

FIG. 4 is an explanatory diagram of a reflecting mirror used in a conventional intruder detection device.

[Explanation of symbols]

 1. Parabolic mirror 2. Infrared detector 4. Infrared transparent window 6. Printed wiring board 7. Convex lens 11. Plate-shaped reflector 12. Round tray base 20. Intruder Detection Device of the Present Invention L. Field of view M. Central monitoring line D. Height of circular tray base

Claims (2)

[Claims] 1. A parabolic mirror on the outer circumference of an infrared detecting element 2 in an apparatus for providing an infrared detecting element having a light receiving surface at a focal position of a parabolic mirror and detecting an intruding action by an output signal from the detecting element. 1 is provided with a dish-shaped reflecting mirror 11 arranged to face the parabolic mirror 1, and the field of view of the reflecting mirror 11 sensed by the detecting element 2 through the parabolic mirror 1 covers the outer peripheral region of the parabolic mirror 1. The central optical axis of the parabolic mirror 1
A convex lens 7 for focusing is fitted on the light receiving surface of the detection element 2 to establish a central monitoring line M in the visual field range that penetrates the parabolic mirror 1, and the reflecting mirror 11 causes the parabolic mirror 11 to emit light. The object plane mirror 1 is composed of a plurality of split plane mirrors formed by a plane including a straight line forming a ridge extending radially around the optical axis of the object mirror 1 and a straight line forming a valley. An intruder detection device, wherein the tilt angle of the parabolic mirror 1 with respect to the optical axis is set to an angle within a range in which the field of view is not obstructed by the adjacent split plane mirrors. 2. A parabolic mirror 1 comprising a detecting element 2 and a reflecting mirror 1.
2. The intruder detection device according to claim 1, wherein the infrared ray transmissive window 4 has a conical slope shape and surrounds the periphery of the mounting base 12 of FIG.