JPH0741689U - Infrared human body detector - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to realize an infrared human body detection device for detecting infrared rays emitted from a human body, by efficiently changing the shape of a detection area with a simple structure. [Configuration] Two optical means having different focal lengths are provided, and the optical means having the shorter focal length can be relocated.
A configuration in which two detection areas are switched by moving the optical means.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an infrared human body detection device for detecting infrared energy emitted by a human body, and to an arrangement of optical means capable of greatly changing the detection area.

[0002]

[Prior art]

 An infrared human body detection device usually has a detection area formed by one infrared detection element and optical means having one or more optical axes. This detection area was usually fixed from the beginning, but some of them had been put into practical use where the shape of the detection area could be changed with a simple operation.

For example, in an apparatus of a type in which a Fresnel lens is formed on a dome-shaped cover, the built-in infrared detection element is fixed, and the cover part included in the viewing angle is provided with a combination of different optical axes. The first Fresnel lens is formed, and the second Fresnel lens composed of another combination of optical axes is formed on the other dome-shaped cover portion not included in the viewing angle, and the dome-shaped cover is rotated. Then, one in which one of the two Frenel lenses is fixed so that it is within the viewing angle of the infrared detection element has been put into practical use.

Further, in addition to this, just before a part of the multi-parabolic mirror having a plurality of fan-shaped optical axes, another sub-reflecting mirror can be freely moved in and out from outside the viewing angle of the infrared detection element. Some also change the fan-shaped spread angle (angle of the detection area). (Actual fair No. 2-28467)

[0005]

[Problems to be solved by the device]

 In the conventional detection area switching method, the distance between the infrared detection element and the center of the optical system (focal length) was almost constant, so even if the fan-shaped three-dimensional detection area that covers a medium distance is long, Even in a planar detection area that covers a distance, the spread of the optical axis formed by one optical system and the infrared detection element was the same.

FIG. 2A is a plan view of a fan-shaped detection area, FIG. 2B is a side view thereof, and FIG. 3A is a plan view of a surface-shaped detection area that covers a long distance. Yes, and FIG. 3B is a side view thereof. 2 and 3 are both formed by an optical system having the same focal length, but the horizontal widths D1 and D2 at the longest portions of the respective detection zones are different. This means that in this type of detecting device for detecting a moving human, the amount of change in infrared energy reaching the infrared detecting element is different even for a human moving at the same speed.

Normally, it is ideal to determine the focal length of the optical system so that the value of D approaches the width of a human, but under the condition limited to one focal length, two types of such It was very difficult to realize different types of detection areas and maintain proper sensitivity of both.

[0008]

[Means for Solving the Problems]

 In the present invention, two optical means having different focal lengths are arranged within the viewing angle of the infrared detecting element, and the optical means having a short focal length can be removed as needed to selectively use the optical means having two kinds of focal lengths. It is what

[0009]

[Action]

 According to the present invention, two types of detection areas can be realized by optical means having different focal lengths by moving one optical means without moving the position of the infrared detecting element.

[0010]

【Example】

 FIG. 1 is a view showing a cross section of an infrared human body detection device of the present invention, FIG. 1 (a) shows a state in which a multi-parabolic mirror 3 is used, and FIG. 1 (b) shows a state in which a Fresnel lens 4 is used. It is a thing. A dome-shaped cover 6 having a Fresnel lens 4 is fixed to the chassis 1 to form a container that covers the entire infrared human body detection device. An infrared detection element 2 inside and a multi-parabola mirror 3 having a plurality of fan-shaped optical axes are fixed to a chassis 1 via a support mechanism 5.

In the state shown in FIG. 1A, the infrared energy incident from the lower left of the drawing passes through the cover 6 and is focused on the infrared detecting element 2 by the multi-parabola mirror 3. The detection area at this time is a fan-shaped detection area as shown in FIG. FIG. 1B shows a state in which the multi-parabola mirror 3 is moved and fixed outside the viewing angle of the infrared detection element 2. In this state, the infrared energy incident from the right side of the drawing is focused on the infrared detecting element 2 by the Fresnel lens 4 formed on the cover 6. The detection area at this time is a long-distance detection area formed by two detection zones above and below.

Since the focal length of the Fresnel lens 4 is about twice the focal length of the multi-parabola mirror 3, the divergence angle of one detection zone of the Fresnel lens 4 is about the same as that of the multi-parabola mirror. It is 1/2, which is more suitable for detecting a person moving far away from the infrared human body detection device. The means for relocating the multi-parabola mirror 3 may be housed in the apparatus in a folded form as shown in FIG. 1B, but the multi-parabola mirror 3 is removed from the support mechanism 5 and the other means in the apparatus is removed. It can be fixed in place or removed from the device.

[0013]

[Effect of device]

 As described above, according to the present invention, an appropriate detection area can be formed by moving one of the two optical means having different focal lengths, and the optical system that makes use of the characteristics of the focal length can be formed. The efficiency of the optical system of this type of device equipped with the area switching mechanism has been greatly improved. Further, in an embodiment in which a Fresnel lens is formed on a dome-shaped cover and a multi-parabola mirror that can be relocated inside is incorporated, the direction in which infrared energy is collected (direction of the detection area) differs by 180 ° depending on the detection area switching. However, since it is a dome type device shape, even if it is rotated 180 ° and installed, the external appearance of the device after installation becomes axisymmetric, and there is no problem in design. As for the configuration, since it is only necessary to form a Fresnel lens on the cover of this type of conventional detection device, it is possible to switch the detection area with the same member as the detection device using the conventional multi-parabola mirror, which is cost effective. Is also great.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an infrared human body detection device of the present invention.

FIG. 2 is a diagram showing a fan-shaped detection area.

FIG. 3 is a diagram showing a detection area that covers a long distance in a planar manner.

[Explanation of symbols]

 1. Chassis 2. Infrared detector 3. Multi-parabola mirror 4. Fresnel lens 5. Support mechanism 6. cover

Claims (3)

[Scope of utility model registration request] 1. An infrared detecting element for detecting infrared rays emitted by a human body, a first optical means for focusing infrared rays from a plurality of different directions on the infrared detecting element, and a viewing angle of the infrared detecting element. A second optical unit that is disposed and has a focal length longer than that of the first optical unit; and an optical system relocating unit that moves the first optical unit out of the viewing angle of the infrared detection element. Characteristic infrared human body detection device. 2. The infrared human body detection device according to claim 1, wherein the first optical means is a multi-parabolic mirror having a plurality of optical axes, and the second optical means is a Fresnel lens. 3. The first optical means is a multi-parabolic mirror having a plurality of fan-shaped optical axes, and the second optical means is a cover formed of a dome-shaped infrared-transparent resin. The infrared human body detection device according to claim 1, wherein the infrared human body detection device is a Fresnel lens provided in the.