JP3324271B2 - Hot wire detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-wire detector for detecting the presence of a person by capturing a hot wire.

[0002]

2. Description of the Related Art FIG. 6 schematically shows an example of a conventional hot-wire detector. FIG. 6 is a configuration diagram of an example of a hot-wire detector of a type in which heat rays are condensed by a plurality of condensing optical systems on one pyroelectric element, and a long-range and a short-range are simultaneously monitored. FIG. 2 is a configuration diagram of a hot-wire detector installed in a horizontal direction. In the figure, 1 is a pyroelectric element for detecting a heat ray, 2a to 2a
d is a condenser lens which is an optical system. Condensing lens 2a
2d are arranged such that their focal points converge on one point, and the pyroelectric element 1 is arranged at the focal position. The condenser lens 2d is configured to monitor the shortest distance, and the condenser lens 2a is configured to monitor the longest distance. With this configuration,
A plurality of detection areas can be provided, and it is possible to simultaneously monitor a long distance and a short distance.

Next, the detection area will be described in detail with reference to FIG. FIG. 7 shows one condenser lens 2a,
Pyroelectric element 1 arranged at the focal position of condensing lens 2a
FIG. 3 is an explanatory diagram showing a detection area formed by the above.
In FIG. 7, reference numeral 3 denotes a detection element of the pyroelectric element 1, which is a portion for detecting a heat ray. Since the detection element 3 has a size of about φ2, the actual detection area has a spread of θ. This indicates that the detection area increases as the distance increases. When the focal length of the condenser lens 2a is f and the diameter of the detection element is d, the angle θ
Becomes as follows.

[0004]

(Equation 1)

[0005] In addition, the spreading distance D in one direction of the detection area at a position away from the condenser lens 2a by a distance L is:
It becomes like the following formula.

[0006]

(Equation 2)

As shown in the equation (2), the detection area becomes wider as the distance is detected. As described above, in a configuration in which one pyroelectric element 1 simultaneously monitors a long distance and a short distance, the detection area is large at a long distance and the detection area is narrow at a short distance. If it crosses, it will cross in a long time at a long distance, and in a short time at a short distance. When a person crosses the detection area, the detection element 3 outputs a pulse-like output signal, but outputs an output signal corresponding to the time when the person crosses. In a hot-wire detector of a type in which one pyroelectric element 1 simultaneously monitors a long distance and a short distance, the pyroelectric element 1
This means that a wideband amplifier must be used as an amplifier for amplifying the output signal of (detection element 3). In other words, the amplifier used in the hot-wire detector of the type described above needs to respond to a relatively low frequency in order to watch a long distance, and to respond to a relatively high frequency in order to watch a short distance. That's what it means.

FIG. 8 shows the frequency characteristics of the gain of the wide-band amplifier described above. When you try to inexpensively constitute a broadband amplifier, frequency characteristics of the gain becomes as shown in FIG. 8, and amplifies when detected by the long-range detection area (response) required is at the frequency f ₁ gain, or, it may gain at other frequency range than the gain at the frequency f ₂ that amplifies necessary (response) is when detecting a short distance of the detection area is increased,
There has been a problem that unnecessary noises are easily spread and malfunctions are likely to occur. In addition, the wide bandwidth that can respond is itself a cause of inducing unnecessary noise.

Next, a different example of the conventional hot-wire detector will be described with reference to FIG. The figure is a configuration diagram showing an example of a hot-wire detector provided with one mirror as an optical system. In FIG. 9, reference numeral 4 denotes a pyroelectric element, 5 denotes a detection element, and 6 denotes a mirror for collecting heat rays. The mirror 6 is
The curved surfaces are configured so that heat rays A, B, and C having different incident angles are condensed at one point. FIG. 9 is a configuration diagram of a hot-wire detector installed on a ceiling or the like as viewed from the horizontal direction. A hot wire A is a hot wire radiated from a position closest to the hot-wire detector in the detection area, and a hot wire B is This is a heat ray radiated from a position farthest from the hot-wire detector in the detection area.

The details of the detection area of the hot-wire detector shown in FIG. 9 will be described with reference to FIG. In FIG. 10, 5 is a detection element, and 6 is a mirror. As described above, since the detection element has a size of about φ2, the detection area spreads at an angle θ even in the case of using the mirror 6 to condense heat rays. When the distance between the detection element 5 and the mirror 6 (the distance in the direction perpendicular to the surface of the detection element 5) is k, the angle θ is expressed by the following equation.

[0011]

(Equation 3)

Further, assuming that the distance from the hot-wire detector to the object to be detected (human body) is L, the spread D of the detection area is as follows.

[0013]

(Equation 4)

As shown in the equation (4), it can be seen that the detection area becomes wider as the distance is monitored.
The detection area in the case of the hot-wire detector shown in FIG. 9 will be described with reference to FIG. 11. In the case of the hot-wire A radiated from a position closest to the hot-wire detector in the detection area,
(A), the distance k ₁ from the reflection position of the heat ray A mirror 6 to the detection element 5, the heat ray B shown in (b)
It is longer than the distance k ₂ in the case of. In other words, in the case of the hot wire A radiated from the position closest to the hot wire detector in the detection area, the distance from the mirror 6 to the detection element 5 in the direction parallel to the center line of the hot wire A shown in FIG. f ₁ is
The mirror 6 in the direction parallel to the center line of the heating wire B shown in FIG.
Longer than the distance f ₂ to the detection element 5.
From equation (4), it can be seen that as the distance k becomes longer, the spread D of the detection area becomes smaller. In other words, the spread of the detection area is smaller in the case of a heat ray radiated from a position near the hot-wire detector. From the points described above, when the hot-wire detector having the structure shown in FIG. 9 is installed on a ceiling or the like, as shown in FIG. Type detector 7
It can be seen that the farther away the detection area becomes, the larger the detection area becomes.

Thus, as in the case of the hot-wire detector having the structure shown in FIG. 6, if the speed at which a person moves is constant, the hot-wire detector is determined by the distance from the hot-wire detector to the detection location. Since the amplifier must respond at different frequencies, it is necessary to use a wideband amplifier if one pyroelectric element is to be used for both long-distance and short-distance alerting. A hot-wire detector having the structure shown in FIG. As in the case described above, there is a problem that unnecessary noises are easily spread and malfunctions are likely to occur.

[0016]

As described above, if one pyroelectric element is used to warn both a long distance and a short distance, a wide band amplifier must be used due to the difference in the spread of the detection area. There is a problem that it becomes easy to unnecessarily noise and to easily malfunction. Further, there is a problem that the number of parts increases to prevent malfunction.

The present invention has been made in view of the above problems, and
An object of the present invention is to provide a structure of a hot-wire detector that can warn a long distance and a short distance with one pyroelectric element and can improve reliability with less malfunction.

[0018]

According to a first aspect of the present invention, there is provided a hot-wire detector comprising: a pyroelectric element; and a plurality of condensers for condensing a heat ray radiated from an object to be detected onto the pyroelectric element. In the hot-wire detector for detecting the object to be detected present at various positions from a long distance to a short distance, the pyroelectric element is a part for detecting a heat ray,
The part is provided with a detection element having a predetermined size.
Ri, regardless of the distance from the hot-wire detector to the object to be detected object, wherein as time across the detection area of the position where the detected object is present that is substantially the same, each of the optical systems, the most Concentrates heat rays at close detection positions
Moves the focus position of the pyroelectric element
Set to the rear position, and as the detection position gets farther,
Those that collect those heat rays have their focal position
Is set at a position closer to the pyroelectric element than the position .

A hot-wire detector according to a second aspect of the present invention includes a pyroelectric element and a mirror for condensing a heat ray radiated from an object to be detected on the pyroelectric element, and is provided at various positions from a long distance to a short distance. In the hot-wire detector for detecting the object to be detected, the pyroelectric element is a portion for detecting a hot ray, and
Is provided with a detection element having a predetermined size
Cage, regardless of the distance from the hot-wire detector to the object to be detected object, wherein as time across the detection area of the position where the detected object is present that is substantially the same, the closest detection position of the mirror The point where heat rays are collected is the focus
The position passes through the sensing element and is behind the pyroelectric element.
, And as the detection position gets farther,
Where the line is focused, its focal position is
It is characterized in that the shape is set so as to be located at a position approaching the pyroelectric element .

[0020]

In the hot-wire detector according to the first aspect, as shown in FIG. 1, regardless of the distance from the pyroelectric element 8 (detection element) to the detected object, detection of the position where the detected object exists is detected. Time to cross area (distance to cross detection area)
Since the focal positions of the condenser lenses 9a to 9c are set so that J) becomes substantially the same, regardless of the distance from the pyroelectric element 8 to the detected object, the focal position is determined at the position where the detected object exists. The output signal output from the pyroelectric element 8 when crossing the detection area is substantially the same.

In the hot-wire detector according to the second aspect, as shown in FIG. 3, regardless of the distance from the pyroelectric element 11 to the object to be detected (irrespective of the incident direction of the heat ray), the object to be detected is Since the curved surface of the mirror 12 is set so that the focal position is different for the heat rays incident from each direction so that the time traversing the detection area at the existing position (the distance traversing the detection area) is substantially the same, Regardless of the distance from the element 11 to the object to be detected (regardless of the direction of incidence of the heat ray), the output signal output from the pyroelectric element 11 when the object to be detected crosses the detection area at the position where the object exists is detected. It is almost the same.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the hot-wire detector according to the present invention will be described with reference to FIG. FIG. 1 is a configuration diagram showing a schematic configuration of the inside of a hot-wire detector, and shows a hot-wire detector installed on a ceiling or the like viewed from a horizontal direction. In FIG. 1, reference numeral 8 denotes a pyroelectric element;
Reference numerals a to 9c denote condensing lenses that condense heat rays radiated from the detected object onto the pyroelectric element 8. Condenser lens 9a-
Each of 9c is set such that the width J of the detection area (the distance at which the person crosses the detection area) at the detection position corresponding to the condenser lenses 9a to 9c is substantially the same. In Figure 1, a nearest detection position detected position converging lens 9 c is intended that the hot-wire detector, to rather large in width J, the focus position 10 c of the condenser lens 9 c is other compared to the condenser lens 9b, 9 a focus position 10b, 10 a, is set in the farthest position of the pyroelectric element 8 backwards. That is,
The focus position of the condenser lens corresponding to the detection position is set closer to the pyroelectric element 8 as the detection position becomes farther. With this configuration, the output signal output from the pyroelectric element 8 when the object to be detected crosses the detection area at the position where the object exists is substantially the same. It can be. That is, as shown in the frequency characteristic diagram of the amplifier in FIG. 2, for example, the frequency around the frequency f3 is optimized so as to respond to the output signal output from the pyroelectric element 8 when a person crosses the detection area. If the frequency characteristics of the amplifier are set so that the gain becomes higher, the hot-wire detector can be configured at low cost without making it easy to spread unnecessary noise.

Next, another embodiment of the hot-wire detector of the present invention will be described with reference to FIG. In the embodiment shown in FIG. 3, the hot-wire detector of the present invention is configured by using the hot-wire detector having the structure shown in FIG. 9, and FIG. 3 shows a hot-wire detector installed on a ceiling or the like horizontally. It is the block diagram seen from the direction. In FIG.
Reference numeral 11 denotes a pyroelectric element, and 12 denotes a substantially concave mirror for condensing heat rays on the pyroelectric element 11. 13a to 13e are heating wires, 1
Reference numerals 4a to 14e denote focal positions of the respective heat rays, and the heat rays 12a radiated from the direction A are radiated from the detection position closest to the hot-wire detector. The mirror 12 is set so that the position (focal position 14 a to 14 e) for condensing the heat ray incident from that direction becomes closer to the pyroelectric element 11 from the direction A to the direction B.
With this configuration, the detection area of the hot-wire detector is as shown in FIG.

In FIG. 4, reference numeral 15 denotes a hot-wire detector installed on a ceiling or the like, and a detection area 16 is a substantially rectangular parallelepiped area. As shown in the figure, for example, direction A, direction C, direction
Since the width (distance traversed by a person) of the detection area existing in E becomes substantially the same (width J), a narrow band amplifier can be used.

FIG. 5 shows still another embodiment of the present invention. FIG. 5 is a configuration diagram illustrating an example in which the hot-wire detector of the present invention is configured using a full-circle hot-wire detector. The cross section of the hot-wire detector 17 installed on a ceiling or the like is viewed from a horizontal direction. It is sectional drawing at the time of seeing. In addition, 18 is a pyroelectric element, 19
a, 19b and 19c are condenser lenses, and 20a and 20b are mirrors. A condenser lens 19a, 19b, of 19c, the condenser lens 19 c are disposed substantially directly below the position of the pyroelectric element 18 is for guard closest detection position in the hot-wire detector 17. Heat rays condensed by the condensing lens 19 a from the sensing area is focused on the pyroelectric element 18 is reflected by the mirror 20a and the mirror 20b. As described above, even when the heat ray is focused on the pyroelectric element 18 by combining the condenser lens and the mirror, the width of the detection position targeted by each optical system (distance that a person crosses the detection area).
So that the focal positions 2 of the respective optical systems are substantially the same.
By setting 1a, 21b and 21c, it becomes possible to use a narrow band amplifier.

The number, shape, and position of the optical system are not limited to those in the embodiment.

[0027]

As described above, according to the hot-wire detector according to the first and second aspects, the position at which the detected object exists regardless of the distance from the hot-wire detector to the detected object. The focal position of the optical system was set so that the time required to cross the detection area (distance across the detection area) is approximately the same, regardless of the distance from the hot-wire detector to the detected object, Since the output signal output from the pyroelectric element when crossing the detection area at the position where it exists is substantially the same, it is possible to use a narrow band amplifier, so that unnecessary noise will not be generated and malfunction will occur. Since it can be prevented, reliability can be improved. Also, components for noise suppression are not required.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a hot-wire detector of the present invention.

FIG. 2 is a diagram showing an example of a frequency characteristic of an amplifier of the hot-wire detector of the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the hot-wire detector of the present invention.

FIG. 4 is an explanatory diagram showing an example of a detection area of the hot-wire detector of the present invention.

FIG. 5 is a sectional view showing still another embodiment of the hot-wire detector of the present invention.

FIG. 6 is a configuration diagram illustrating an example of a conventional hot-wire detector.

FIG. 7 is an explanatory diagram illustrating a detection area of a pyroelectric element.

FIG. 8 is a diagram illustrating an example of frequency characteristics of an amplifier of a conventional hot-wire detector.

FIG. 9 is a configuration diagram showing a different example of the conventional hot-wire detector.

FIG. 10 is an explanatory diagram illustrating a detection area of a pyroelectric element.

FIG. 11 is an explanatory diagram illustrating a detection area of a pyroelectric element.

FIG. 12 is an explanatory diagram illustrating a detection area of a conventional hot-wire detector.

[Explanation of symbols]

 8, 11, 18 Pyroelectric elements 9a to 9c, 19a to 19c Condensing lens (optical system) 12, 20a, 20b Mirror

Claims (2)

(57) [Claims] An object comprising: a pyroelectric element; and a plurality of optical systems for condensing a heat ray radiated from the detected object on the pyroelectric element, wherein the detected object exists at various positions from a long distance to a short distance. In the hot-wire detector for detecting the pyroelectric element,
A part that detects heat rays, and that part has a predetermined size.
Includes a detection element having, wherein the hot-wire detector regardless of the distance to the detected object, wherein as time across the detection area of the position where the detected object is present that is substantially the same, the optical Each of the systems is the closest
For those that focus heat rays at the detection position, the focus position is detected.
Pass through the element and set at the position behind the pyroelectric element,
Focus the heat rays as the detection position gets farther
The focus position of the device is more on the pyroelectric element than the rear position.
A hot-wire detector characterized in that it is set at an approaching position . 2. A pyroelectric element comprising: a pyroelectric element; and a mirror for condensing a heat ray radiated from the detected object onto the pyroelectric element, and detects the detected object existing at various positions from a long distance to a short distance. In the hot-wire detector, the pyroelectric element is configured to detect a hot wire.
The part to be detected, which part has a predetermined size
Detector element , regardless of the distance from the hot-wire detector to the object to be detected, such that the time required for the object to be detected to cross the detection area at the position where the object is located is substantially the same, The hot wire at the nearest detection position
The focal point is where the focal position passes through the detection element.
To the position behind the pyroelectric element, and the detection position becomes far
Where the heat rays are focused according to
Position will be closer to the pyroelectric element than the rear position.
Hot-wire detector, characterized in that setting the cormorants shape.