Radiant energy – Invisible radiant energy responsive electric signalling – Infrared responsive
Patent
1995-07-28
1997-06-24
Tokar, Michael J.
Radiant energy
Invisible radiant energy responsive electric signalling
Infrared responsive
250DIG1, G01J 508, G01B 1110
Patent
active
056419643
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an infrared human body detector having a wide sensitive angle.
BACKGROUND ART
One conventional infrared human body detector which has a wider sensitive angle than ordinary infrared human body detectors and has been evaluated as excellent is disclosed in U.S. Pat. No. 4,644,147. The disclosed infrared human body detector has a sensitive angle which is 90 degrees on both sides of a central sensitivity axis of the detector. The disclosed infrared human body detector is suitably mounted on a flat wall or ceiling.
There has not been available an infrared human body detector having a sensitive angle ranging from 180 to 270 degrees, suitable in an arrangement as shown in FIG. 4 of the accompanying drawings for monitoring an entire region P around a rectangular house H with infrared human body detectors S, nor has there been an infrared human body detector having a sensitive angle ranging from 270 to 360 degrees for monitoring a large room with a high ceiling, a garden, or the like. To monitor these areas, a plurality of infrared human body detectors have to be combined with each other, but such a combination is very uneconomical. Specifically, for monitoring a corner (270 degrees) of a house with infrared human body detectors, it has heretofore been necessary to install two infrared human body detectors, each having a sensitive angle of 180 degrees, on respective surfaces that jointly make up the corner. This system is highly disadvantageous because the price of the required infrared human body detectors and the expenses needed to install them are about twice those which would be necessary to employ one infrared human body detector.
Monitoring a large room with a high ceiling, a garden, or the like with a conventional infrared human body detector D2, as shown in FIG. 11(b) of the accompanying drawings, having a sensitive angle of 180 degrees, is also highly disadvantageous in that the initial and running costs are about twice those of an infrared human body detector according to the present invention for the reasons described above.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide an infrared human body detector for detecting movement of a human body or the like in a monitored area, the infrared human body detector having a sensitive angle of 180 degrees or greater suitable for monitoring a house, a large room with a high ceiling, a garden, or the like, or a wider sensitive angle ranging from 270 to 360 degrees, for thereby reducing the initial and running costs thereof to about half those of the conventional infrared human body detectors.
According to the present invention, there is provided an infrared human body detector comprising: disposed in a plane; about the infrared detector in surrounding relation thereto; infrared ray converging members for reflecting, in a primary fashion, rays applied inwardly through the respective groups of divided infrared ray converging members; and divided infrared ray converging members for introducing the reflected rays from the primary reflecting mirror means within a sensitive angle of the infrared detector to apply the rays to the light-detecting surfaces thereof, the secondary reflecting mirror means having a reflecting surface sufficiently small as compared with the surface areas of the infrared ray converging members.
The groups of divided infrared ray converging members may comprise groups of Fresnel lenses, for example, the Fresnel lenses being disposed concentrically about the infrared detector in an angle of at least about 270 degrees.
If the infrared detector comprises a planar detecting member having light-detecting surfaces on its opposite principal surfaces which extend in a direction perpendicular to the plane referred to above, then the secondary reflecting mirror means includes secondary reflecting surfaces disposed in respective left- and right-hand positions on opposite sides of the axis of the planar detecting member, and each of the secondary reflecting surfaces is dispo
REFERENCES:
patent: 4644147 (1987-02-01), Zublin
Carrier Joseph P.
Nippon Ceramic Co., Ltd.
Tokar Michael J.
Tyler Virgil O.
Weiner Irving M.
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