JP2016170105A - Infrared sensing element, radiation thermometer, and human body detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an infrared sensing element capable of reliably sensing temperature changes of an infrared transmissive member caused by external factors, and to provide a radiation thermometer and human body detector.SOLUTION: A radiation thermometer includes an infrared detection unit 11 comprising; a measurement infrared sensing element 11a configured to detect infrared rays radiating from a measurement target object M via a Fresnel lens L; and temperature-correction infrared sensing element 11b having an infrared sensing surface thereof covered with an optical filter 11c that allows detection of only infrared rays of wavelengths in a dead band of the Fresnel lens L, and being configured to detect infrared rays originating from temperature changes of the Fresnel lens L itself caused by external factors. Infrared energy sensed by the measurement infrared sensing element 11a is corrected using infrared energy originating from temperature changes of the Fresnel lens L itself sensed by the temperature-correction infrared sensing element 11b, which allows for accurately sensing temperature of the measurement target object M.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an infrared detecting element that detects infrared rays emitted from an object such as a pyroelectric element or a thermopile, and a radiation thermometer that is an infrared detecting device that detects the temperature of a detection target (object or region) using the infrared detecting element. In addition, the present invention relates to a human body detector.

  In the following Patent Document 1, an infrared detector that uses a thermopile as an infrared detecting element for detecting infrared rays radiated from a detection object and measures the intensity of infrared rays radiated from the detection object in a non-contact manner to detect a temperature value. A radiation thermometer as an apparatus is disclosed.

  This radiation thermometer is a first temperature sensor that detects infrared energy in order for the user to know the determination result of whether the actual temperature of the measurement object and the temperature of the measurement object satisfy a predetermined condition ( A second temperature sensor (thermopile) for detecting infrared energy radiated from the first temperature sensor is provided between the thermopile) and a third temperature sensor (thermistor) for detecting the ambient temperature, and output from each sensor. Temperature information of the measurement target that has been temperature-corrected is acquired from the first, second, and third temperature information.

  Patent Document 2 listed below discloses a human body detector that is an infrared detection device that detects a change in infrared rays emitted from an object and detects whether or not the object that has entered the monitoring region is a human body based on a temperature change. Is disclosed.

  This human body detector is, for example, an act of attaching a shielding material such as gummed tape to the cover of the human body detector, or applying a paint of the same color as the cover or a transparent liquid that does not easily transmit infrared rays to the cover surface or injecting it into the cover. In order to detect an action that prevents the human body from being detected by crafting the cover of the human body detector (the so-called “planning action”), the temperature change of the cover surface is applied to a predetermined location on the inner surface side of the cover. In order to detect, a surface temperature detection surface made of a material having high thermal emissivity and thermal conductivity is provided, and the presence or absence of a plan is determined by the temperature change of the detection surface.

JP 7-280650 A Japanese Patent No. 4260341

  By the way, the conventional radiation thermometer including the radiation thermometer disclosed in Patent Document 1 is a Fresnel lens for condensing infrared rays radiated from a measurement object on a thermopile. As shown in FIG. 9, a thermistor for temperature correction is arranged near the end of the Fresnel lens.

  This Fresnel lens is particularly susceptible to the center of the lens, so it would be ideal to place a thermistor near the center of the lens. 9 is disposed in the vicinity of the lens end as shown in FIG.

However, since the thermistor is a contact-type thermal element, when it is installed at the lens end, the following problems 1 to 3 occur, so that accurate temperature correction cannot be performed due to the temperature difference between the lens end and the lens center. There was a problem.
(Problem 1)
Since the lens end portion is not affected by a direct temperature change due to infrared condensing, there is a problem that the temperature change is smaller than that of the lens center portion.
(Problem 2)
Since the lens end portion is in contact with the cylindrical portion to which the Fresnel lens is attached, there is a problem that the heat capacity increases and the temperature change becomes small.
(Problem 3)
Since the material of the Fresnel lens is formed of a synthetic resin such as acrylic or polyethylene, there is a problem that the thermal conductivity is low and the temperature is not easily transmitted to the end of the lens, and the temperature change is small.

In addition, as shown in Examples 1 and 2 below, the above-mentioned problems are likely to occur when measuring a high-temperature measurement object or when the temperature of the measurement environment changes extremely. There is a need for a method for improving the temperature detection error of an object.
(Case 1)
For example, when the ambient temperature is about 20 ° C. and the object to be measured is a metal heated to 250 ° C., strong heat radiation from the metal heated to a high temperature for a predetermined time immediately after detection as shown in FIG. The lens temperature rises due to (fogging) and is detected at a temperature (256 ° C.) higher than the actual temperature (250 ° C.), and an error of about 6 ° C. occurs.
(Case 2)
For example, when the ambient temperature changes from about 40 ° C. to 20 ° C. and the object to be measured is 0 ° C. ice, the lens cools for a predetermined time immediately after detection as shown in FIG. Therefore, it is detected at a temperature (−2.2 ° C.) lower than the actual temperature (0 ° C.), and an error of about 2 ° C. occurs.

  Moreover, in the radiation thermometer of patent document 1, although the 2nd temperature sensor is provided between the 1st temperature sensor and the 3rd temperature sensor, the infrared rays radiated | emitted from a 1st temperature sensor are detected, and temperature compensation is carried out. Also, it is impossible to compensate for the temperature error caused by the temperature change in the central portion of the Fresnel lens as described above.

  Furthermore, in the human body detector disclosed in Patent Document 2, a surface temperature detection surface is provided on the inner surface of the cover from which the infrared light receiving zone set so as to be able to monitor the entire monitoring area is removed so as not to hinder human body detection processing. Although the size and shape of the monitoring area are all different for each location to be monitored, the equipment designer repeats experiments several times to adjust the angle of the human body detection polygon mirror and surface temperature detection mirror. The surface temperature detection surface must be set at a position outside the light receiving zone, which is complicated.

  This is because the installation location of the surface temperature detection surface may not be anywhere in the cover, and in order to detect the planning action with high accuracy, the human body detector is easily subjected to the planning action (particularly facing the monitoring area on the cover surface). This is because it is necessary to provide a surface temperature detection surface at a location).

  Also, if the monitoring area is relatively wide and the infrared light receiving zone must be set to a wide range, the surface temperature detection surface may not be provided at an appropriate position, so consider the position of the infrared light receiving zone. The development of a new human body detector that can detect the plan of the cover without using it is desired.

  As described above, the problems common to the infrared thermometer and human body detector described above are members that transmit infrared rays (a Fresnel lens for a radiation thermometer, an infrared transmission cover for a human body detector). ) Due to the influence of external thermal action (for example, thermal radiation from the measurement object, temperature change in the measurement environment, and the act of planning on the cover surface), the infrared transmission member itself changes in temperature, and the detection result (detected infrared ray) An error occurs in the temperature value or temperature change according to the amount.

Therefore, the present invention has been made in view of the above problems, and in order to detect a temperature change caused by some external factor, the infrared transmitting member detects only infrared rays caused by the temperature change of the infrared transmitting member. It is an object of the present invention to provide an infrared detecting element that can be used.
Further, a radiation thermometer having a function of correcting a temperature value according to the infrared intensity radiated from a measurement object using the infrared detection element and a human body detector having a function of detecting a plan action for the infrared transmitting member are provided. It is intended to provide.

In order to achieve the above-described object, the infrared detection element according to claim 1 is an infrared detection element that detects infrared rays emitted from a measurement object via an infrared transmission member that transmits infrared rays.
An optical filter that transmits only infrared light having a wavelength in the same range as the dead band where the infrared transmittance of the infrared transmitting member is extremely low is provided so as to cover the infrared detection surface.

  The infrared detection element according to claim 2 is the infrared detection element according to claim 1, wherein the infrared detection element is a thermopile.

  An infrared detection element according to claim 3 is the infrared detection element according to claim 1, wherein the infrared detection element is a pyroelectric element.

Further, the radiation thermometer according to claim 4 is an infrared detecting element for measurement that detects infrared rays radiated from a measurement object via a Fresnel lens made of an infrared transmitting member;
Among the infrared rays generated when the temperature of the Fresnel lens is changed due to an external factor, an optical filter that transmits only infrared rays having the same wavelength as the dead band where the infrared transmittance of the Fresnel lens is extremely low is an infrared detection surface. An infrared detecting element for temperature correction provided to cover
An infrared detector comprising:
The temperature value according to the intensity of infrared rays emitted from the measurement object detected by the measurement infrared detection element, the temperature value according to the intensity of infrared rays emitted from the Fresnel lens detected by the temperature correction infrared detection element. An arithmetic unit for performing temperature correction processing using
It is provided with.

Further, the human body detector according to claim 5 detects an infrared ray radiated from a human body that has entered the monitoring area through a cover that transmits infrared rays, and detects the presence or absence of the human body based on a change amount of the infrared rays. A detection unit;
A plan detecting unit for determining whether or not the cover has been planned,
A human body detector comprising:
The plan detection unit
An infrared light receiving unit for detecting a plan having an image detecting element provided so that an optical filter that transmits only infrared rays having a wavelength in the same range as the dead band where the infrared transmittance in the cover is extremely low is provided to cover the infrared detection surface; ,
A plan determination unit that determines the presence or absence of a plan action by comparing a light reception signal generated according to the amount of received infrared light input to the plan detection element and a preset plan judgment threshold;
It is characterized by having prepared.

  In the infrared detecting element of the present invention, an optical filter that transmits only infrared light having the same wavelength as the dead band where the infrared transmittance of the infrared transmitting member is extremely low is provided so as to cover the infrared detecting surface. When employed in a radiation thermometer, if the Fresnel lens, which is an infrared transmitting member, changes in temperature due to some external factor, the Fresnel lens does not detect the infrared light of the measurement object that passes through the Fresnel lens. It is possible to detect only infrared rays having a wavelength in the same range as the dead band due to the temperature change. Therefore, even if an error occurs in the temperature value according to the infrared intensity detected from the measurement object, the temperature value of the Fresnel lens itself can be obtained from the infrared intensity detected by the infrared detection element provided with the optical filter. Therefore, the temperature value of the measurement object can be corrected to a correct value.

  In addition, when the infrared detector of the present invention is employed in a human body detector, infrared rays when a human body enters the monitoring area are not detected, and infrared rays caused by the temperature change of the cover that occurs when the cover is planned Since only the infrared rays in the dead band wavelength range can be detected, the plan action can be detected reliably.

(A) is a graph which shows the relationship between the infrared transmittance | permeability of the cover of the human body detector which is an infrared detector, and an infrared wavelength, (b) is a dead zone detected by the plan detection part of the human body detection in Embodiment 2. It is a figure which shows the infrared waveform of the wavelength of the same region. It is a schematic sectional drawing of the radiation thermometer used as Embodiment 1 of the infrared detecting device concerning the present invention. It is a functional block diagram of the radiation thermometer. It is a schematic sectional drawing of the human body detector used as Embodiment 2 of the infrared rays detection device concerning the present invention. It is a functional block diagram of a human body detector. The figure which shows an example of the circuit structure of the human body determination part and plan determination part of a human body detector (A) is a schematic diagram which shows the detection state of the infrared rays at the time of human body detection, (b) is a schematic diagram which shows the detection state of the infrared rays at the time of plan detection. It is a figure which shows the output waveform at the time of the infrared detection of the human body detection process and plan measure detection process of the same human body detector. It is a schematic sectional drawing of the radiation thermometer which is the conventional infrared rays detection apparatus. (A) is a graph which shows the temperature change when a high-temperature measuring object is measured using a radiation thermometer, (b) is when a measurement is performed with a radiation thermometer in a measurement environment where the temperature changes extremely. It is a graph which shows the temperature change of a measuring object.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited by this embodiment, and all other forms, examples, operation techniques, etc. that can be implemented by those skilled in the art based on this form are included in the scope of the present invention. .

  The radiation thermometer 10 and the human body detector 20 which are the infrared detectors 1 according to the present invention are mounted on each device when detecting infrared rays radiated from the measurement object M or a human body entering the monitoring area. The infrared detecting element is formed of a material that transmits infrared rays (in the case of the radiation thermometer 10, the Fresnel lens L is used for the radiation thermometer 10, and the cover 20b is used for the human body detector 20). It is detected by the electric element).

  The applicant of the present application solved the problem that the infrared transmitting member of the infrared detecting device described in the section of [Problems to be solved by the invention] is caused by the temperature change of the transmitting member itself due to the influence of external thermal action. As a result of intensive studies, it was found that the infrared transmitting member has a wavelength region (hereinafter referred to as “dead band”) having extremely low infrared transmittance.

FIG. 1A is a graph showing a relationship between infrared wavelength (μm) and transmittance (% T) in a polyethylene cover 20 b of the human body detector 20 that is the infrared detector 1.
As shown in the figure, it is confirmed that the cover 20b has several wavelength regions (in particular, about 3.5 μm, about 6.8 μm, and 13.8 μm in the figure) with extremely low infrared transmittance. it can. In other words, the “dead band” known by the inventors of the present application is a wavelength region in which the infrared transmittance is extremely low, and the infrared ray emitted from the human body does not pass through the cover 20b and cannot be used for human body detection. It is the wavelength range.

  Note that the graph of FIG. 1A is merely an example, and the infrared transmittance and the wavelength band of the dead band change depending on the material and thickness of the cover 20b to be used. Any wavelength region that has an extremely low infrared transmittance and does not affect human body detection may be used.

  By the way, when the human body detector 20 is taken as an example of the infrared detector, the plan detection for the human body detector 20 detects a change in the amount of infrared rays due to a temperature change that occurs in the cover 20b due to the plan action. If infrared rays in a wavelength range other than the band are detected, the detected infrared rays are infrared rays caused by temperature changes caused by the movement of the human body in the monitoring region, or infrared rays caused by temperature changes caused by the action of the plan. Judgment is difficult.

  However, the above-described dead band is used as an infrared detection wavelength region at the time of plan detection, and among the infrared rays caused by temperature changes caused by the plan action as shown in FIG. By detecting only the change in the amount of infrared rays caused by the temperature change of the cover 20b caused by the plan action on the cover 20b without providing a surface temperature detection surface on the cover 20b as in the case of Patent Document 1 as a measure for the plan action. It was found that the change in the amount of infrared rays caused by the human body intrusion that occurred in the monitoring area can be distinguished.

  The same applies to the Fresnel lens L that is an infrared transmitting member in the radiation thermometer 10 that is the infrared detection device 1, and the temperature of the central portion of the Fresnel lens L changes depending on the thermal radiation of the measurement object M and the measurement environment. However, it is possible to distinguish from the amount of infrared rays emitted from the measuring object M by detecting the amount of infrared rays caused by the temperature change generated at the center of the Fresnel lens L using the dead zone of the Fresnel lens L itself. Measurement is possible by correcting the temperature value according to the intensity of the infrared ray detected from the measuring object M with the temperature value of the center part of the Fresnel lens L according to the intensity of the infrared ray that has passed through the dead zone of the Fresnel lens L. An accurate temperature value of the object M can be obtained.

  Hereinafter, each component requirement and processing operation in the infrared detection device 1 (the radiation thermometer 10 as the first embodiment and the human body detector 20 as the second embodiment) according to the present invention that has been developed based on the above-described new technical concept will be described. To do.

[1. Embodiment 1]
First, the radiation thermometer 10 used as 1st Embodiment of the infrared rays detection apparatus 1 which concerns on this invention is demonstrated.
The radiation thermometer 10 described in the first embodiment is used when measuring the surface temperature of various objects that are difficult to measure in a contact type without contact. The infrared thermometer 10 emitted from the surface of the measurement object M is used. It is an apparatus that measures the surface temperature of the measurement object M by measuring the strength.

<1-1. About equipment configuration>
As shown in FIG. 2 or FIG. 3, the radiation thermometer 10 according to the first embodiment includes an infrared detection unit 11, a compensation temperature detection unit 12, an amplification unit 13, an A / D conversion unit 14, and a calculation unit. 15 and a temperature display unit 16.

  The infrared detection unit 11 detects infrared rays having wavelengths other than the dead band of the Fresnel lens L formed of a synthetic resin (infrared transmitting member) having infrared transparency such as polyethylene. Infrared detecting element 11a for temperature correction, and infrared correcting element 11b for temperature correction for detecting infrared light in the same region as the dead band of Fresnel lens L among infrared rays generated when the temperature of Fresnel lens L changes due to some external factor. The

  The infrared detecting element 11a for measurement is composed of a thermopile element, which is an infrared detecting element, and receives infrared light emitted from the measurement object M via the Fresnel lens L, and is caused by the intensity of the received infrared light. An electric signal (analog signal) obtained by photoelectrically converting the heat energy is output to the amplifying unit 13 as a measurement temperature signal.

  That is, the measurement infrared detection element 11a is an element for detecting infrared rays emitted from the measurement object M and having wavelengths other than the dead band in the Fresnel lens L.

  The infrared correction element 11b for temperature correction is composed of a thermopile element that is an infrared detection element, and the Fresnel lens L depends on external factors (thermal radiation from the measurement object M, temperature change in the measurement environment caused by movement of the measurement position, etc.). Of the infrared rays caused by the temperature change occurring in itself, only an infrared ray having a wavelength in the same region as the dead zone of the Fresnel lens L is received, and an electric signal (analogue) obtained by photoelectrically converting the thermal energy caused by the intensity of the received infrared ray Signal) is output to the amplifying unit 13 as a correction temperature signal.

  Further, an optical filter 11c for detecting only infrared rays having a wavelength included in the dead band of the Fresnel lens L is provided on the infrared detection surface of the temperature correction infrared detection element 11b so as to cover the detection surface. .

  The optical filter 11c is a so-called band-pass filter that allows the temperature-correcting infrared detection element 11b to detect only infrared light having a wavelength included in the dead band of the Fresnel lens L and not to detect infrared light in a wavelength band other than the dead band. It is an optical component that plays a role, and is provided in front of the infrared detection surface of the temperature correction infrared detection element 11b. Therefore, the infrared pass band of the optical filter 11c is set so that only infrared rays having a wavelength included in the dead band determined by the infrared transmittance of the Fresnel lens L to be used pass.

  Note that the infrared pass band width of the optical filter 11c is set to be at least the same as the dead band of the Fresnel lens L to be used, and an experiment or the like is performed in advance in consideration of external factors caused by the temperature change of the Fresnel lens L. By doing so, it is set in a wavelength range where infrared rays caused by the temperature change of the Fresnel lens L can be detected. Therefore, when there are a plurality of dead bands depending on the Fresnel lens L to be used, an appropriate dead band is selected according to the wavelength range of infrared rays caused by temperature changes due to external factors based on the above experiment, and only that wavelength band is passed. What is necessary is just to design the optical filter 11c so that it may.

  That is, the infrared ray detecting element 11b for temperature correction has a wavelength in the same region as the dead band in the Fresnel lens L among infrared rays radiated when the temperature of the Fresnel lens L changes due to some external factor through the optical filter 11c. Only infrared rays can be detected.

  The compensation temperature detection unit 12 is composed of a temperature sensor such as a thermistor and is installed in the vicinity of the infrared detection unit 11. The compensation temperature detector 12 detects a change in temperature of the measurement infrared detection element 11a and the temperature correction infrared detection element 11b itself as a change in resistance value, and uses the detected resistance value (analog signal) as a compensation temperature signal. Is output to the A / D converter 14. If the installation distance between the measurement infrared detection element 11a and the temperature correction infrared detection element 11b is increased due to the design of the device, it is preferable to install the compensation temperature detection unit 12 in the vicinity of each element.

The amplifying unit 13 receives a measurement temperature signal that is an analog signal output from the measurement infrared detection element 11a and a correction temperature signal that is an analog signal output from the temperature correction infrared detection element 11b, and outputs these signals. The signal is amplified to a signal level that can be converted by the A / D converter 14 and then output to the A / D converter 14.

  The A / D converter 14 A / D converts the analog signal output from the amplifier 13 and the analog signal indicating the resistance value output from the compensation temperature detector 12 into a digital signal, and then the arithmetic unit 15 Is output.

  That is, the A / D conversion unit 14 converts the measurement temperature signal, which is an analog signal amplified to a predetermined signal level from the amplification unit 13, into a digital signal, and then converts the measurement temperature signal into a digital signal. 15 is output. The A / D conversion unit 14 converts the correction temperature signal, which is an analog signal amplified to a predetermined signal level from the amplification unit 13, into a digital signal, and then calculates the digital temperature correction signal. To the unit 15. Further, the A / D conversion unit 14 converts the analog signal indicating the resistance value output from the compensation temperature detection unit 12 into a digital signal, and outputs the digital temperature compensation signal to the calculation unit 15.

  The arithmetic unit 15 is constituted by a processor such as a CPU (Central Processing Unit), for example, and various signals (measurement temperature signal, correction temperature signal, compensation temperature signal) converted into digital signals by the A / D conversion unit 14. Is used to measure the temperature compensation of each element 11a, 11b of the infrared detection unit 11 using the compensation temperature signal detected by the compensation temperature detection unit 12, and from the temperature signal for measurement and the temperature signal for correction. A correction process of the temperature value (absolute value) of the object M and a temperature value calculation process are performed.

Infrared energy detected by the measurement infrared detecting element 11a through the Fresnel lens L includes infrared energy emitted from the Fresnel lens L itself radiated from the Fresnel lens L in addition to infrared energy emitted from the measurement object M. Is also included.
Therefore, the calculation unit 15 calculates the temperature from “the infrared energy radiated from the measurement object M + the infrared energy radiated from the Fresnel lens L”, which is the infrared energy detected by the measurement infrared detecting element 11a indicated by the measurement temperature signal. By subtracting the “infrared energy radiated from the Fresnel lens L” detected by the correction infrared detecting element 11b, the infrared energy radiated from the Fresnel lens L is offset, and the infrared energy detected by the measuring infrared detecting element 11a Is corrected only to the infrared energy radiated from the measuring object M.

For example, when the temperature of the measurement object M is “150 ° C.” and the temperature of the Fresnel lens L affected by the radiation of the measurement object M is “35 ° C.”, the measurement infrared detection element 11 a is the measurement object. Infrared energy corresponding to “150 ° C.” that is the temperature of M and infrared energy corresponding to “35 ° C.” that is the temperature of the Fresnel lens L itself radiated from the Fresnel lens L are simultaneously detected, so that “185” in total is detected. The infrared energy corresponding to “° C.” is detected, and the actual temperature and error of the measurement object M are generated.
However, infrared energy corresponding to “35 ° C.”, which is the temperature of the Fresnel lens L itself detected by the temperature correcting infrared detection element 11b, from infrared energy corresponding to “185 ° C.” detected by the measurement infrared detection element 11a. By subtracting, infrared energy corresponding to “150 ° C.”, which is the actual temperature of the measuring object M, can be converted into a temperature value. Therefore, an accurate temperature value of the measurement object M can be acquired.

  The temperature display unit 16 includes a display device (LCD (liquid crystal display) or the like), and displays the temperature value calculated by the calculation unit 15 as a numerical value.

<1-2. About processing operations>
Next, the processing operation of the radiation thermometer 10 described above will be described.

  First, when temperature measurement of the measurement object M is started, the measurement infrared detection element 11a detects infrared rays radiated from the measurement object M via the Fresnel lens L, and the temperature correction infrared detection element 11b Infrared rays emitted from the lens L itself are detected. In parallel with this, the compensation temperature detector 12 detects a change in temperature of each element 11a, 11b of the infrared detector 11 as a change in resistance value, and detects the detected resistance value (analog signal). ) To the A / D converter 14 as a compensation temperature signal.

  At this time, since the temperature correction infrared detecting element 11b detects infrared rays via the optical filter 11c, the infrared rays from the measuring object M passing through the Fresnel lens L are not detected, but are emitted from the Fresnel lens L itself. Of the infrared rays, only the infrared rays having the same wavelength as the dead zone of the Fresnel lens L are detected.

  Next, an electrical signal (analog signal) obtained by photoelectrically converting thermal energy caused by the infrared intensity of the measurement object M detected by the measurement infrared detection element 11a is output to the amplification unit 13 as a measurement temperature signal. Also, the temperature correcting infrared detecting element 11b receives only infrared rays having a wavelength in the same region as the dead band of the Fresnel lens L among infrared rays caused by temperature changes caused in the Fresnel lens L itself due to external factors. An electric signal (analog signal) obtained by photoelectrically converting the thermal energy resulting from the intensity of the infrared light is output to the amplifying unit 13 as a correction temperature signal.

  Next, the amplification unit 13 is a signal that can be converted by the A / D conversion unit 14 from the measurement temperature signal output from the measurement infrared detection element 11a and the correction temperature signal output from the temperature correction infrared detection element 11b. After being amplified to the level, it is output to the A / D converter 14. Then, the A / D conversion unit 14 converts an analog signal indicating the measurement temperature signal and the correction temperature signal, which are analog signals output from the amplification unit 13, and the resistance value output from the compensation temperature detection unit 12, into A / D. After being converted into a digital signal, it is output to the arithmetic unit 15.

  The calculation unit 15 performs temperature compensation processing using the compensation temperature signal detected by the compensation temperature detection unit 12 for temperature compensation of the elements 11 a and 11 b of the infrared detection unit 11 and outputs from the A / D conversion unit 14. The temperature value (absolute value) of the measuring object M is calculated from the measured temperature signal and correction temperature signal. That is, the infrared energy radiated from the Fresnel lens L detected by the temperature correction infrared detection element 11b indicated by the correction temperature signal is subtracted from the infrared energy detected by the measurement infrared detection element 11a indicated by the measurement temperature signal. Thus, the infrared energy emitted from the Fresnel lens L is canceled out, and only the infrared energy emitted from the measurement object M is acquired.

  Thereafter, the calculation unit 15 converts the infrared energy radiated from the measurement object M acquired by the correction process into a temperature value, and the temperature display unit 16 displays the temperature information as a temperature display.

<1-3. Effect of Embodiment 1>
As described above, the radiation thermometer 10 according to the first embodiment described above is insensitive to the measurement infrared detection element 11a that detects the infrared rays radiated from the measurement object M via the Fresnel lens L and the Fresnel lens L. An optical filter 11c that detects only infrared rays having a wavelength included in the band is provided so as to cover the infrared detection surface, and detects infrared rays due to temperature changes of the Fresnel lens L itself due to external factors. An infrared detector 11 having an element 11b is provided.

  Thereby, when detecting the infrared ray radiated from the measuring object M in the infrared detecting unit 11, only the infrared ray generated when the temperature of the Fresnel lens L itself is changed by an external factor in the temperature correcting infrared detecting element 11b is detected. Therefore, the infrared energy detected by the infrared detecting element 11a for measurement can be corrected with the infrared energy caused by the temperature change of the Fresnel lens L itself detected by the infrared detecting element 11b for temperature correction. Accurate temperature detection of the object M is possible.

[2. Second Embodiment]
Next, the human body detector 20 which becomes 2nd Embodiment of the infrared rays detection apparatus which concerns on this invention is demonstrated.

<2-1. About equipment configuration>
As shown in FIG. 4 or FIG. 5, the human body detector 20 of the present example has a function of detecting the presence or absence of a human body in a monitoring region based on a change amount of infrared rays accompanying movement of a human body to be detected, and mainly a cover 20b. Detect whether the cover 20b has been shielded by the act of spraying or applying, for example, spray or paint, other liquids that absorb or block infrared rays, tape, etc. to prevent human detection by the human detector 20 In order to realize the function to perform, a human body detection unit 21, an image plan detection unit 22, a control unit 23, an output unit 24, and a power supply unit 25 are provided in the housing 20a.

  Further, in order to prevent the human body detection unit 21, the plan measure detection unit 22, the control unit 23, the output unit 24, and the power supply unit 25 from being exposed to the outside, a cover 20b that covers them is attached to the housing 20a.

  The cover 20b is formed of a material (infrared transmitting member) that easily transmits infrared rays radiated from a human body entering the monitoring area, such as polyethylene or polypropylene. In addition, the cover 20b is color-adjusted so as to have a cloudy color or a relatively low brightness so that the internal components cannot be visually recognized from the outside for the purpose of preventing the mischief of the ambient light other than infrared rays and preventing mischief. ing.

  The human body detection unit 21 is configured to receive a human body detection infrared light receiving unit 21A that receives infrared light from the infrared light receiving zone E1 set in the monitoring region, and the human body in the monitoring region according to the amount of infrared light received by the human body detection infrared light receiving unit 21A. And a human body determination unit 21B for determining the presence or absence.

  The human body detecting infrared light receiving unit 21A detects the amount of change in infrared light accompanying the movement of the human body within the monitoring region, and includes an infrared light receiving mirror 21Aa and a human body detecting element 21Ab.

  The infrared light receiving mirror 21Aa is composed of a polygonal mirror divided into a plurality of regions in the vertical and horizontal directions so as to form an infrared light receiving zone E1 in a desired monitoring region by the human body detecting element 21Ab. The infrared light receiving mirror 21Aa receives infrared rays accompanying the movement of the human body that has entered the infrared light receiving zone E1 set in the monitoring area, and guides the infrared rays to the detection surface of the human body detecting element 21Ab located at the focal point on the optical axis. Yes.

  The human body detecting element 21Ab is an infrared detecting element such as a pyroelectric element or a thermopile, and is fixed on the circuit board 20c in the housing 20a. The human body detection element 21Ab is configured by differentially connecting two detection elements having different polarities in order to prevent erroneous detection due to disturbance such as sunlight. The human body detecting element 21Ab receives the infrared light from the infrared light receiving zone E1 reflected and guided by the infrared light receiving mirror 21Aa, and outputs a received light signal generated according to the received light amount of the received infrared light to the human body determination unit 21B. ing.

  The human body determination unit 21B compares a light reception signal generated according to the amount of received infrared light input to the human body detection element 21Ab of the human body detection infrared light reception unit 21A with a threshold value (human body determination threshold value) determined in advance in an experiment. The presence or absence of a human body is determined.

  Specifically, the human body determination unit 21B includes an amplifier 21Ba and comparators 21Bb and 21Bc, as shown in FIG. 6, for example. A light reception signal of the human body detecting element 21Ab is input to the amplifier 21Ba, and an output of the amplifier 21Ba and a threshold value Vref1 + are input to the comparator 21Bb. Further, the output of the amplifier 21Ba and the threshold value Vref1- are input to the comparator 21Bc.

  Therefore, the upper limit threshold value Vref1 + and the lower limit threshold value Vref1- are set and input as appropriate threshold values for determining the presence or absence of a human body calculated in advance in the human body determination unit 21B. Then, when the light reception signal from the human body detecting element 21Ab amplified by the amplifier 21Ba exceeds the threshold value Vref1 + or Vref1- within the human body determination time T1, it is determined that there is a human body, Otherwise, it is determined that there is no human body. In addition, the human body detection signal is output to the control unit 23 only when it is determined that there is a human body.

  The human body determination time T <b> 1 is started by using the input timing when the light receiving signal is input from the human body detecting element 21 </ b> Ab by the control unit 23 as a trigger, and is reset to measure a predetermined time.

  The plan detecting unit 22 receives the infrared rays for detecting the infrared rays due to the temperature change caused in the cover 20b due to the plan action, and the cover 20b according to the amount of infrared light received by the plan detecting infrared receiving unit 22A. A plan determining unit 22B that determines the presence or absence of the plan.

  The plan-detecting infrared light receiving unit 22A includes a plan-detecting element 22Aa that detects an infrared ray caused by a temperature change of the cover 20b due to a plan action, and an optical filter 22Ab provided so as to cover the infrared detection surface of the plan-detecting element 22Aa. And is fixed to the circuit board 20d in the housing 20a.

  The scheme detection element 22Aa is configured by an infrared detection element such as a pyroelectric element. The design detection element 22Aa receives infrared rays included in the radiant heat of the cover 20b generated by the plan action from the design detection zone E2 set on the back surface of the cover 20b, and receives light generated according to the received amount of the received infrared rays. The signal is output to the scheme determination unit 22B. Note that the plan detection zone E2 is preferably set so as to include a portion where the plan action is likely to be performed in the cover 20b (particularly the back side of the cover 20b facing the monitoring area) as shown in FIG.

  The optical filter 22Ab serves as a so-called band-pass filter that causes the image detection element 22Aa to detect only infrared light having a wavelength included in the dead band of the cover 20b to be used, and prevents detection of infrared light in a wavelength band other than the dead band. Is provided so as to overlap the infrared detection surface of the image detection element 22Aa. Therefore, the infrared pass band of the optical filter 22Ab is set so that only infrared rays having a wavelength included in the dead band determined by the infrared transmittance of the cover 20b to be used pass.

  The infrared pass band width of the optical filter 22Ab is set so as to be at least the same as the dead band of the cover 20b to be used, and the state (material and thickness) of the cover 20b to be used and the installation of the human body detector 20 Environment (installation height, temperature, presence / absence of environmental change due to weather, etc.), various planned actions (for example, sticking a light-shielding seal, spraying liquid with spray, applying liquid with brush, injecting liquid with syringe, etc.) By performing an experiment in advance in consideration of the above factors, the wavelength range is set such that infrared rays caused by the temperature change of the cover 20b generated when the human body detector 20 is planned can be detected. Therefore, when there are a plurality of dead bands depending on the cover 20b to be used, an appropriate dead band is selected in accordance with the infrared wavelength band resulting from the temperature change caused by the plan action obtained based on the experiment, and the wavelength band It is only necessary to design the optical filter 22Ab so as to pass only through.

  As described above, the plan detecting unit 22 included in the human body detector 20 of the present example has a set dead band (in the illustrated example, the dead band is 3.3 μm to 3.8 μm, as shown in FIG. 1B). Since an optical filter 22Ab that passes only infrared rays having a wavelength in the same region (solid line waveform in the figure) is provided so as to cover the infrared detection surface of the design detection element 22Aa, the human body is within the monitoring region. Infrared rays when entering are not detected, and only infrared rays caused by a temperature change of the cover 20b generated when the cover 20b is planned can be detected, so that the planning action can be reliably detected.

  The plan determination unit 22B compares a light reception signal generated according to the amount of received infrared light input to the plan detection element 22Aa of the plan detection infrared light receiving unit 22A and a threshold (plan determination threshold) determined in advance by experiment. The presence or absence of a plan is determined.

More specifically, the plan determining unit 22B includes an amplifier 22Ba, comparators 22Bb and 22Bc, and a logical sum (OR) circuit 22Bd, as shown in FIG. 6, for example. The amplifier 22Ba receives the light reception signal of the scheme detection element 22Aa, the comparator 22Bb receives the output of the amplifier 22Ba and the threshold value Vref2 +, and the comparator 22Bc receives the output of the amplifier 22Ba and the threshold value Vref2-.

  That is, the upper limit threshold Vref2 + and the lower limit threshold Vref2- are set and input as appropriate thresholds for determining whether or not the temperature change of the cover 20b is calculated in advance in the plan determination unit 22B. Then, when the light reception signal from the design detection element 22Aa amplified by the amplifier 22Ba exceeds the threshold value Vref2 + or Vref2- within a design determination time T2, the determination is made that the cover 20b is planned. If not, it is determined that there is no plan change of the cover 20b. When it is determined that there is a plan, the plan detection signal is output to the control unit 23.

  The plan determination time T2 is started by the control unit 23 using the input timing when the received light signal is input from the plan detection element 22Aa as a trigger, and reset for a predetermined time.

  As described above, in the human body detector 20 of the present example, as shown in FIG. 7A, the infrared light accompanying the movement of the human body received from the infrared light receiving zone E1 set in the monitoring region is transmitted through the cover 20b. The human body detecting infrared light receiving unit 21A receives the light, but the plan detecting infrared light receiving unit 22A is provided with the optical filter 22Ab so that the infrared light transmitted through the cover 20b is not received.

  On the other hand, as shown in FIG. 7B, the infrared detection unit 22A for detecting the plan is the same wavelength range as the dead band of the cover 20b among the infrared rays caused by the temperature change caused by the plan action of the cover 20b by spraying or the like. Since the optical filter 22Ab is provided on the infrared detection surface of the design detecting element 22Aa so that only the infrared rays are detected, infrared rays in a wavelength region other than the dead zone are not detected. Therefore, the infrared rays radiated from the human body are not erroneously detected as the plan action, and only the temperature change due to the plan action can be detected.

  The control unit 23 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), or a processor such as an MPU (Micro-Processing Unit) having these functions. Based on the human body detection signal from 21B and the plan detection signal from the plan determination unit 22B, the output unit 24 controls the output of the abnormal signal (the abnormal signal accompanying the human body detection, the abnormal signal accompanying the plan detection) to the output destination. Yes.

  Further, the control unit 23 includes a timer 23a such as a timer. The human body determination time T1 is measured at the time of human body detection processing (time measurement start processing and timekeeping time reset processing), and the plan determination time T2 at the time of plan detection processing. Performs timekeeping processing (timekeeping start processing and timekeeping time reset processing). And the control part 23 outputs a predetermined | prescribed abnormal signal to an output destination via the output part 24, after measuring the human body determination time T1 or the plan determination time T2.

  The output unit 24 outputs an abnormal signal indicating the presence / absence of human body detection or the presence / absence of a plan action to the output destination under the control of the control unit 23.

  The output destination of the abnormal signal includes, for example, a sounding device such as a buzzer, a display device such as an LED, and a PC (personal computer) of a security company that monitors the monitoring area, and outputs an abnormal signal indicating an abnormality to these. . Thereby, each device as the output destination notifies the occurrence of an abnormality by a predetermined alarm action (ringing process, lighting / flashing process, character display process on the display screen, etc.) based on the input abnormality signal.

  In addition, it is good also as a structure which makes the human body detector 20 equip the human body detector 20 with the sounding device and display apparatus used as an output destination, and when the human body detector 20 detects a plan, the human body detector 20 itself carries out an alarm operation.

  The power supply unit 25 is a general commercial power supply unit, a power supply unit in which various batteries such as a button battery and a dry battery (regardless of a primary battery or a secondary battery) can be attached and detached, or solar power or solar power using a photovoltaic effect. It is composed of any photovoltaic module that directly converts light energy, such as illumination light, into electric power, and appropriately supplies driving power to each part of the human body detector 20.

<2-2. About processing operations>
Next, the processing operation of the human body detector 20 described above will be described with reference to FIG. The processing operation in the human body detector 20 of the present example is roughly divided into processing operations related to human body detection processing for detecting a human body that has entered the monitoring area, and processing related to plan detection processing for detecting the presence or absence of a planning action on the cover 20b. There is movement.

(Processing based on human body detection)
In the human body detection process by the human body detector 20 of this example, when a human body enters the infrared light receiving zone E1 set in the monitoring area, a temperature change occurs in the infrared light receiving zone E1 as the human body moves. And the infrared rays resulting from this temperature change permeate | transmit the cover 20b, and are received by the infrared detection part 21A for human body detection.

  Next, when receiving infrared rays, the human body detecting infrared light receiving unit 21A outputs a received light signal (five times in the example) to the human body determining unit 21B according to the amount of infrared rays received as shown in FIG. At this time, the controller 23 starts counting the human body determination time T1.

  The human body determination unit 21B compares the received light reception signal with a preset human body determination threshold, and the light reception signal input from the human body detection infrared light reception unit 21A sets the human body determination threshold within the human body determination time T1. It is determined whether or not a predetermined number of times has been exceeded. For example, when the number of times that the received signal exceeds the human body determination threshold is set to 3, the number of times exceeds the number in the example of FIG.

The human body determination unit 21B outputs a human body detection signal to the control unit 23 only when it is determined that there is a human body. The control unit 23 outputs an abnormal signal accompanying human body detection to the output destination via the output unit 24.
Thereby, it is notified that a human body has entered the monitoring area at the output destination.

(Processing based on plan detection)
In the plan detection process by the human body detector 20 in this example, when any plan action is performed on the cover 20b, a temperature change occurs in the cover 20b. Then, the infrared detecting unit 22A for detecting the scheme detects only infrared rays having a wavelength in the same region as the dead band from the back surface of the cover 20b among the infrared rays caused by the temperature change in the scheme detecting zone E2 via the optical filter 22Ab. .

  Next, when the infrared rays receiving unit 22A for detecting the plan is received, the received light signal (twice in the example) according to the amount of received infrared rays is output to the plan determining unit 22B as shown in FIG. At this time, the control unit 23 starts counting the plan determination time T2.

  The plan determination unit 22B compares the received light reception signal with a preset plan determination threshold, and the light reception signal input from the plan detection infrared light reception unit 22A sets the plan determination threshold within the plan determination time T2. It is determined whether or not the number of times has been exceeded. For example, when the number of times that the received signal exceeds the plan determination threshold is set to two, the number of times exceeds the number in the example of FIG.

Then, the plan determination unit 22B outputs a plan detection signal to the control unit 23 only when it is determined that there is a plan. The control unit 23 outputs an abnormal signal associated with the plan detection to the output destination via the output unit 24. This notifies the cover 20b that some planning action has been performed at the output destination.

<2-3. Effects of Embodiment 2>
As described above, the human body detector 20 includes the human body detection unit 21 that detects a human body that has entered the monitoring area, and the plan detection unit 22 that determines whether or not a plan action has been performed on the cover 20b. The image detection unit 22 is provided with an optical filter 22Ab that allows only infrared light having a wavelength in the same region as the dead band of the cover 20b to pass over the infrared detection surface of the image detection element 22Aa.

  As a result, the infrared rays when the human body enters the monitoring area are not detected in the plan detection unit 22, and only the infrared rays caused by the temperature change of the cover 20b that occurs when the cover 20b is planned can be detected. It is possible to reliably detect the plan action.

1 ... Infrared detector (10 ... Radiation thermometer, 20 ... Human body detector)
11 ... Infrared detector (11a ... Infrared detector for measurement temperature, 11b Infrared detector for temperature correction)
DESCRIPTION OF SYMBOLS 12 ... Compensation temperature detection part 13 ... Amplification part 14 ... A / D conversion part 15 ... Operation part 16 ... Temperature display part 20a ... Case 20b ... Cover 20c, 20d ... Circuit board 21 ... Human body detection part 21A ... For human body detection Infrared light receiving part (21Aa ... infrared receiving mirror, 21Ab ... human body detecting element)
21B ... Human body determination unit 22 ... Plane detection unit 22A ... Infrared light receiving unit for plan detection (22Aa ... Plane detection element, 22Ab ... Optical filter)
22B ... Planning determination part 23 ... Control part (23a ... Time measuring means)
24 ... Output unit 25 ... Power supply unit E1 ... Infrared light receiving zone E2 ... Plant detection zone

Claims (5)

An infrared detection element that detects infrared rays emitted from a measurement object via an infrared transmission member that transmits infrared rays,
An infrared detection element, wherein an optical filter that transmits only infrared rays having a wavelength in the same range as the dead band where the infrared transmittance of the infrared transmission member is extremely low is provided so as to cover the infrared detection surface. The infrared detection element according to claim 1, wherein the infrared detection element is a thermopile. The infrared detection element according to claim 1, wherein the infrared detection element is a pyroelectric element. An infrared detection element for measurement that detects infrared rays emitted from the measurement object via a Fresnel lens made of an infrared transmission member;
Among the infrared rays generated when the temperature of the Fresnel lens is changed due to an external factor, an optical filter that transmits only infrared rays having the same wavelength as the dead band where the infrared transmittance of the Fresnel lens is extremely low is an infrared detection surface. An infrared detecting element for temperature correction provided to cover
An infrared detector comprising:
The temperature value according to the intensity of infrared rays emitted from the measurement object detected by the measurement infrared detection element, the temperature value according to the intensity of infrared rays emitted from the Fresnel lens detected by the temperature correction infrared detection element. An arithmetic unit for performing temperature correction processing using
A radiation thermometer characterized by comprising: A human body detection unit that detects infrared rays emitted from a human body that has entered the monitoring area through a cover that transmits infrared rays, and detects the presence or absence of a human body based on the amount of change in the infrared rays;
A plan detecting unit for determining whether or not the cover has been planned,
A human body detector comprising:
The plan detection unit
An infrared light receiving unit for detecting a plan having an image detecting element provided so that an optical filter that transmits only infrared rays having a wavelength in the same range as the dead band where the infrared transmittance in the cover is extremely low is provided to cover the infrared detection surface; ,
A plan determination unit that determines the presence or absence of a plan action by comparing a light reception signal generated according to the amount of received infrared light input to the plan detection element and a preset plan judgment threshold;
A human body detector characterized by comprising

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