JPH09101204A - Pyroelectric infrared detector - Google Patents

Abstract

(57) [PROBLEMS] To provide a pyroelectric infrared detection device having a small size and a simple structure, and to improve the probability of detection of passage of a hot object such as a human body. SOLUTION: A plurality of pyroelectric infrared detection elements, an infrared transmission lens, a chopper mechanism, which are arranged one-dimensionally in a casing, and a signal for selectively amplifying a signal generated in the infrared detection element behind the infrared element are provided. A pyroelectric infrared detection device having a band amplifier is configured, and by arranging a plurality of pyroelectric infrared detection devices, a two-dimensional or three-dimensional human body passage detection band is provided to pass an object such as a human body. Is detected by the time series change of the signal from the infrared detecting element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to measurement of surface temperature of an object and detection of passage of the object using a pyroelectric infrared sensor.

[0002]

2. Description of the Related Art Conventionally, as a method of non-contact temperature measurement, there have been a quantum infrared sensor and a thermal infrared sensor. The quantum infrared sensor has high sensitivity,
It has a fast response speed but requires cooling, and is not suitable for consumer use. On the other hand, thermal infrared sensors have relatively low sensitivity,
It has a slow response speed but is unnecessary, so it has been put to practical use in the consumer market.

Among the thermal infrared sensors, the pyroelectric infrared sensor utilizing the pyroelectric effect is often used for consumer use. FIG. 16A is a structural diagram of a pyroelectric infrared sensor used for detecting a human body, and 1'is a pyroelectric infrared detector, which has only one infrared detecting element. 2 is a Fresnel lens made of polyethylene resin. The Fresnel lens 2 has a light distribution characteristic in the viewing angle as shown in FIG. The pyroelectric infrared sensor has a differential output characteristic,
It produces an output only when the incident infrared ray changes. Therefore, when a person passes in front of the pyroelectric infrared sensor,
Due to the light distribution characteristics of the Fresnel lens 2, infrared rays from the human body are intermittently incident on the pyroelectric infrared sensor, and a signal corresponding to the infrared rays is output as the human body moves.

Further, the four elements arranged as shown in FIG.
By using one pyroelectric infrared detection element 1 and a Fresnel lens 2 and an infrared transmission lens 3 made of polyethylene resin, FIG.
By obtaining the light distribution characteristic as shown in (b), it is possible to detect the moving direction by the time difference between the output signals from the infrared detecting elements accompanying the movement of the human body. For example, FIG.
When the human body is detected by the infrared detection element 1-3 after the human body is detected by the infrared detection element 1-1 as shown in (c), the human body moves in the direction indicated by the arrow 15 in FIG. 17 (b). It has been done. A pyroelectric infrared sensor that detects the moving direction of such a human body has also been put into practical use.

FIG. 18 is a sectional view of a thermal image detecting device using a pyroelectric infrared detecting element. Pyroelectric infrared detector 1 '
2, a plurality of pyroelectric infrared elements 1 are arranged one-dimensionally. A two-dimensional thermal image can be obtained by horizontally rotating in the arrangement direction by a stepping motor 6 and periodically injecting infrared rays by a chopper mechanism 4. There is also an example in which the thermal image detecting device in FIG. 18 is used as a means for realizing comfortable control of an air conditioner by measuring the radiant temperature of a floor or a wall.

Further, for detecting the passage of a human body, the one using a near infrared ray (a) or a photoelectric tube (b) in which a light emitting portion and a light receiving portion are divided as shown in FIG. Used for doors and fences.

[0007]

However, FIG.
Although the pyroelectric infrared sensor having the configuration as shown in FIGS. 6 and 17 can detect a human body and a moving direction, it has a differential output characteristic, and thus cannot detect a human body when the human body stands still. Further, in the pyroelectric infrared sensor of FIG. 17, the movement direction of the human body is limited to the movement direction detection of a total of 12 directions in each of the 3 directions from the infrared detection element.

The human body passage detection method as shown in FIGS. 19 (a) and 19 (b) requires precision in adjusting the optical axes 16 of the light receiving portion and the light emitting portion. You will lose its function if you avoid the rays that connect.

Further, the thermal image detecting device as shown in FIG.
It has a chopper mechanism and can measure the temperature of the surface of an object, and can also detect a stationary human body. However, by moving a plurality of one-dimensionally arranged infrared detection elements as shown in FIG. 5 (a). It takes several seconds to obtain a two-dimensional thermal image, which is not suitable for detecting passage of a human body or the like. Further, since the horizontal rotation is performed, it is not suitable for continuously measuring the temperature at a specific place. In addition, since the stepping motor for horizontal rotation drive and the horizontal rotation portion are provided inside the casing, it is not suitable for downsizing the device itself.

The conventional pyroelectric infrared sensor, human body passage detecting device, and thermal image detecting device have the above-mentioned problems.

The present invention solves the above-mentioned problems of the prior art, and provides a pyroelectric infrared detection device having a compact and simple structure using a plurality of one-dimensionally arranged pyroelectric infrared detection elements. It is intended to be configured.

Further, according to the present invention, a device for detecting the passage of a hot body such as a human body is constructed by using the above-mentioned pyroelectric infrared detecting device, and an infrared detecting area having no blind spot is provided at a human body passing position and the device is installed. The object is to improve the probability of detecting the passage of a hot object such as a human body and the probability of information.

[0013]

In order to solve the above-mentioned problems, the present invention provides a plurality of pyroelectric infrared elements arranged one-dimensionally in a casing, an infrared lens arranged in front of the infrared element, and an incident lens. A chopper mechanism for exciting a change in infrared rays, and a band amplifier for selectively amplifying a signal generated in the infrared ray element are provided behind the infrared ray element.

Further, by installing the pyroelectric infrared detection device in the pass band of a hot object such as a human body, the pyroelectric infrared detection device outputs a time series temperature change to heat the human body or the like. By detecting the passage of an object or by combining a plurality of the pyroelectric infrared detection devices, the moving direction and detection probability of a hot object such as a human body is improved.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is directed to a plurality of one-dimensionally arranged pyroelectric infrared elements in an enclosure, an infrared lens arranged in front of the infrared elements, and a chopper for exciting changes in incident infrared rays. Mechanism, and by providing a band amplifier for selectively amplifying the signal generated in the infrared element behind the infrared element, the radiation temperature at the location corresponding to a plurality of one-dimensionally arranged infrared detection elements at the same time, Moreover, it is possible to provide a simple and small pyroelectric infrared detection device that can detect continuously. Furthermore, a portable pyroelectric infrared detection device can be provided by providing a microcomputer having an input / output or operating a device arranged inside or outside the housing.

In addition, the same function as that of the conventional thermal image detecting device is added by moving the pyroelectric infrared detecting device in the direction perpendicular to the array direction of the infrared detecting elements.

Further, the pyroelectric infrared detecting device can be easily installed in a pass band of a hot body such as a human body, and detects the passage of a human body or by combining a plurality of pyroelectric infrared detecting devices. It is possible to improve the moving direction of the human body and the detection probability.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pyroelectric infrared detector according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a sectional view of a pyroelectric infrared detection device according to one embodiment, and 1'is a pyroelectric infrared detection device in which a plurality of pyroelectric infrared detection devices are arranged one-dimensionally as shown in FIG. It is an infrared detector composed of the element 1. Reference numeral 3 denotes an infrared ray passing lens, which together with the infrared ray detecting element 1 of the infrared ray detector 1'obtains light distribution a, b, ... That is, the pyroelectric infrared detection device uses the strip-shaped light distributions a, b,
Detects the radiated infrared ray of the portion corresponding to h. Reference numeral 4 denotes a chopper mechanism composed of a disk having a partial cutout in the rotor of the flat motor, and when the chopper mechanism 4 is operated at a constant cycle as shown in FIG. 4, the incident infrared ray also changes in synchronization with this. Then, an electric signal output is excited in the pyroelectric infrared element 1 in response to the change in the incident infrared rays.

According to Stefan-Boltzmann's law, this electric signal output V is proportional to the difference between the fourth power of the absolute temperature T _{c of} the chopper and the absolute temperature T _b of the measured object surface, as shown in equation (1).

V = k ₁ · (T _b ⁴ −T _c ⁴ ) (1) (where k ₁ is a proportional constant) However, the difference between the measured object surface absolute temperature T _b and the chopper absolute temperature T _c is small. In case of electrical signal output V
Changes linearly to the difference between T _b and T _c , and can be expressed as in equation (2).

V = k ₂ · (T _b −T _c ) (2) (where k ₂ is a proportional constant) Further, 5 in FIG. 1 is a band amplifier having a chopper cycle as a central pass band, and 50 / The influence of a commercial power supply of 60 Hz or the like and the thermal low-frequency noise of the infrared detection element are reduced, and the obtained electric signal output V is amplified.

Therefore, if k ₂ is obtained, the difference between the measured object surface absolute temperature T _b and the chopper absolute temperature T _c is
(2) can be easily calculated by V / k ₂ from equation if the absolute temperature T _c of the chopper long known in advance, (3) the measurement object surface absolute temperature T _b is determined as.

T _b = T _c + V / k ₂ (3) The thermal image detection device of FIG. 18 also measures the temperature of the portion corresponding to each pyroelectric infrared detection element 1 by the calculation formulas (1) to (3). However, since the pyroelectric infrared detection device of the present invention does not include the stepping motor 6 in the casing, the device can be downsized and the temperature of a specific portion can be continuously measured.

As shown in FIG. 5, the pyroelectric infrared device is horizontally rotated in the direction perpendicular to the arrangement direction of the pyroelectric infrared elements 1 (a).
By moving or linearly moving (b)
The thermal image can be detected in the same manner as the thermal image detection device of No. 8.

FIG. 1B shows the pyroelectric infrared detecting device 8 of the present invention.
It shows the block diagram by function of
FIG. 6 shows the operation flow of the pyroelectric infrared detection device.
In order to detect temperature with a pyroelectric infrared detector,
It is necessary to have a microcomputer 7 that AD-converts the electric signal output V of each pyroelectric infrared detection element 1 (102) and performs the calculation (103) of the equation (3). This microcomputer 7 has a chopper mechanism 4 ( The control (101) and other calculations (104) such as passage detection and movement direction detection are performed, and the result is also output (106). A portable pyroelectric infrared detection device 8 can be provided by incorporating a microcomputer 7, an output display function, a power supply, and the like inside the casing of the pyroelectric infrared detection device 8 of FIG.

By installing the strip-shaped light distributions a, b, ... H of the pyroelectric infrared detector of FIG. 3 in the pass band of an object such as a person, a plurality of pass detection ranges can be obtained as shown in FIG. . The pyroelectric infrared detection device 8 detects the change of the infrared radiation emitted from the object by the chopper mechanism 4 by continuously detecting the electric output signal of the equation (2) and calculating the object surface temperature of the equation (3). For example, as shown in FIG. 8A, it is possible to capture a sudden change in state such as a change in electric signal output V or a change in detected temperature (b) accompanying passage of an object such as a human body.
This makes it possible to detect a situation such as passage or stillness in the passage detection range. Since this pyroelectric infrared detection device alone detects a change in infrared radiation of a passing object, it is not necessary to adjust the optical axes of the light emitting portion and the light receiving portion as in the passage detection device of FIG.

Light distribution characteristics a of the pyroelectric infrared detector 8
Since b, ... H spread out in a fan shape from the pyroelectric infrared detection device as shown in FIG. 3, a wide blind spot exists near the pyroelectric infrared detection device 8 and each pyroelectric infrared detection element 1 is Since they are arranged at intervals as shown in FIG. 2, there are blind spots that occur. Therefore, by arranging the two pyroelectric infrared detection devices 8-1 and 8-2 so as to face each other, it is possible to obtain the pass detection band as shown in FIG. 9A and reduce the blind spot. You can Further, since the pass detection band of the pyroelectric infrared detection device 8 is determined by the angle of view of the infrared transmission lens 2, by arranging the combination of (a) in the vertical direction as shown in FIG. The pass detection band of can be expanded. Further, it is possible to completely eliminate the blind spot by using a plurality of pyroelectric infrared detectors 8 to form a two-dimensional pass detection band as shown in FIGS. 10 (a) and 10 (b). By performing the passage detection by the pyroelectric infrared detection device, it is possible to improve the probability of the passage detection, and even if one of the plurality of devices fails, it is complemented by the other pyroelectric infrared detection devices. Therefore, when the passage detection system is configured, the reliability of the system is also improved.

Further, by arranging the two pyroelectric infrared detectors 8-A and B in parallel as shown in FIG.
It is possible to provide three independent pass detection bands. FIG.
As described above, by observing the object passage detection point 9 due to a sudden change in the electric signal output of each infrared detection element or a sudden change in the detected temperature, the pyroelectric infrared detection as shown in FIG. In addition to detecting the movement in the direction from the device 8-A to 8-B and detecting the stopped state, the movement speed can be detected if the movement time 10 is measured and the width of the pass detection band is known. By analyzing the change in the state of the passage detection point up to the level of each infrared detection element, it is possible to detect that an object such as a human body has crossed "obliquely" or "straight". By installing a plurality of pyroelectric infrared devices 8 in parallel as shown in FIG. 13, it is possible to detect even more detailed movement direction, state and movement speed of the human body. It is also possible to configure each pass detection band as shown in FIG. 9 or FIG. 10, which leads to improvement in accuracy of detection probability, moving direction, state, moving speed, etc. as described above.

Further, by constructing the two-dimensional pass detection bands of FIGS. 9, 10, 11, and 12 composed of a plurality of pyroelectric infrared detectors three-dimensionally as shown in FIG. Information on entry and exit can be obtained. For example, as shown in FIG. 15, if the direction entering the space area constituted by the plurality of pyroelectric infrared detecting devices 8 is detected as ◯ (11) and the exit direction is detected as x (12), it is detected as “enter from the surface A”. Information such as "Move out on side C" or "Move out on side A and go out on side E", and if a space is a room, information such as time in room and absence can be obtained (Fig. 15).

In this way, the passage of the human body is detected by the pyroelectric infrared detection device, and the alarms, lights and doors of automatic doors / elevators arranged outside based on the information obtained as a result. Crime prevention and safety can be improved by activating the opening and closing of (FIG. 6, 106).

[0032]

According to the present invention, as is apparent from the above description,
A plurality of pyroelectric infrared elements arranged one-dimensionally in one casing, an infrared lens arranged in front of the infrared element, a chopper mechanism for exciting a change of incident infrared rays, and an infrared element behind the infrared element. A compact and portable pyroelectric infrared detection device can be constructed by arranging a band amplifier for selectively amplifying the generated signal or by having a microcomputer having an input / output. Further, this pyroelectric infrared detection device can continuously measure the temperature at the same location, and also can detect a thermal image by rotating the pyroelectric infrared detection device by an external horizontal rotation mechanism. It is possible.

Further, in the present pyroelectric infrared detector,
The passage of a human body or the like can be detected by a time-series change of a signal from the infrared detection element, and a blind spot in the passage detection band can be eliminated by spatially combining a plurality of the pyroelectric infrared detection devices. Further, the device can be easily installed, and it can be expected that the accuracy of information such as the detection probability of the passage of a human body, the moving direction, the state such as presence / absence, and the moving speed is improved.

In addition, with the present pyroelectric infrared detector,
Crime prevention and safety can be improved by operating devices such as alarms, lighting devices, and automatic doors based on human body information.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a pyroelectric infrared detection device showing an embodiment of the present invention, and FIG. 1B is a functional block diagram of a pyroelectric infrared detection device according to an embodiment of the present invention. Figure

FIG. 2 is an array diagram of a pyroelectric infrared detection element.

FIG. 3 is a light distribution diagram of a pyroelectric infrared detection device.

FIG. 4 is an explanatory diagram showing the principle of electric signal output generation of the pyroelectric infrared detection element.

5A is an explanatory diagram showing a method of obtaining a thermal image by the pyroelectric infrared detection device of the present invention, and FIG. 5B is the same explanatory diagram.

FIG. 6 is a flowchart showing a series of operations of the pyroelectric infrared detection device according to the present invention.

FIG. 7 is a diagram showing an object passage detection band by the pyroelectric infrared detection device according to the present invention.

FIG. 8 is an explanatory diagram of an object passage detection method by the pyroelectric infrared detection device according to the present invention.

FIG. 9 is a configuration diagram of a pass detection band by a plurality of pyroelectric infrared detection devices according to the present invention.

FIG. 10 is a diagram showing another embodiment in which a two-dimensional pass detection band is constituted by a plurality of pyroelectric infrared detection devices.

FIG. 11 is a configuration diagram of an object passage detection device using two pyroelectric infrared detection devices according to the present invention.

FIG. 12 is an explanatory diagram of a situation of passing an object by the object passage detecting device including the pyroelectric infrared detecting device.

FIG. 13 is a configuration diagram of an object passage detection device including a plurality of pyroelectric infrared detection devices.

FIG. 14 is a configuration diagram of an object passage detection device for a three-dimensional space by a plurality of pyroelectric infrared detection devices according to an embodiment of the present invention.

FIG. 15 is a diagram showing a state of an object by an object passage detection device for a three-dimensional space.

FIG. 16A is an explanatory view of a conventional human body detection pyroelectric infrared sensor. FIG. 16B is the same explanatory view.

FIG. 17A is a quantum layout diagram of a pyroelectric infrared sensor for detecting a human body moving direction which is a conventional example. FIG. 17B is a light distribution diagram of a pyroelectric infrared sensor for detecting a human body moving direction which is a conventional example. ) Is an explanatory diagram of a moving direction detection method using a pyroelectric infrared sensor, which is a conventional example for detecting a moving direction of a human body

FIG. 18 is a cross-sectional view of a conventional thermal image detection device.

FIG. 19 is a schematic view of a human body passage detection device as a conventional example.

[Explanation of symbols]

 1 Pyroelectric Infrared Detector 3 Infrared Transmission Lens 5 Band Amplifier 6 Stepping Motor 8 Pyroelectric Infrared Detector

Claims (4)

[Claims] 1. A plurality of pyroelectric infrared elements arranged one-dimensionally in a casing, an infrared lens arranged in front of the infrared element, a chopper mechanism for exciting a change of incident infrared rays, and the infrared element. A pyroelectric infrared detection device characterized by arranging a band amplifier for selectively amplifying a signal generated in an infrared element behind the, and measuring a temperature in a range corresponding to a plurality of pyroelectric infrared elements. 2. A detection of passage of a hot body such as a human body by arranging one or more of the pyroelectric infrared detection device at a passage place of a hot body such as a human body and forming an infrared detection zone. Pyroelectric infrared detector. 3. In the pyroelectric infrared detection device, a plurality of two-dimensional infrared detection bands formed by a plurality of pyroelectric infrared detection devices are arranged in parallel to detect passage of a hot object such as a human body. 3. The pyroelectric infrared detection device according to claim 2, wherein the detection of the passing direction and the detection of the moving speed are performed based on the time difference. 4. A warm object such as a human body goes in and out of the constructed infrared detection space by three-dimensionally combining two-dimensional infrared detection zones having no blind spots formed in the plurality of pyroelectric infrared detection devices. The pyroelectric infrared detection device according to claim 2, wherein