JPH11167687A - Fire detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detect the existence of a burning matter even under the environment in which sunlight and burning infrared rays coexist about fire detector. SOLUTION: The fire detecting device is provided with an infrared detecting part which receives external light and detects infrared quantity of plural wavelength bands in a near-infrared area of 1-2 μm, a comparator circuit which compares 'infrared ray quantity of a long wavelength side S2' with 'infrared ray quantity of a short wavelength side S1' in the near-infrared area of 1-2 μm, based on the infrared ray quantity of plural wavelength band which is detected by the infrared detecting part and a signaling means which signals the existence of a burning matter when the infrared ray quantity of the side S2 is more than the infrared ray quantity of the side S1 according to the comparison of the comparator circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire detecting device for detecting the presence of a burning material while distinguishing it from sunlight. In particular, the present invention relates to a fire detection device that compares the amount of infrared light in a specific band of near infrared light.

[0002]

2. Description of the Related Art Conventionally, as a fire detection device, a device that detects smoke and a device that detects a rise in ambient temperature are well known. These are suitable for use in monitoring a relatively limited space and detecting the occurrence of a fire. On the other hand, there has been known a device that detects a fire by detecting infrared rays from a combustion product. This type of fire detection device has the advantage that it can detect the occurrence of a relatively distant fire early because it can detect infrared rays from a remote location.

In particular, when an image sensor is used as an infrared sensor, an infrared image is taken,
There is an advantage that the position of the fire point can be easily specified. Hereinafter, such an infrared detection type fire detection device,
A conventional example will be described. Generally, as an infrared detection type fire detection device, a device that detects infrared rays of about 4 μm which are emitted in large amounts from carbon dioxide gas is well known.

However, since the wavelength band of about 4 μm does not pass through an optical lens such as glass, a special lens optical system made of silicon, germanium, or the like must be used. Therefore, there has been a problem that this type of fire detection device cannot be configured at low cost.

In view of the above, a fire detection device that detects infrared rays in the near infrared region because an optical lens such as glass is used is conceivable. However, infrared rays in the near-infrared region of this kind are included in a large amount in sunlight. Therefore, simply detecting infrared rays in the near-infrared region does not make it possible to distinguish between combustion products and sunlight, and there is a high possibility that sunlight is erroneously determined.

In order to solve such an erroneous determination, there has been disclosed an apparatus which performs a two-wavelength detection comparison between a near infrared region and a photographic infrared region (Japanese Patent Application Laid-Open No. 61-1986).
-32195 publication). Hereinafter, the outline of the device disclosed in this publication will be described. First, a bare silicon photodiode is used for detecting the wavelength band on the short wavelength side.
This silicon photodiode detects a photographic infrared region from visible light to near infrared with a wavelength of 0.9 μm as a central wavelength.

On the other hand, for detection of the wavelength band on the long wavelength side, Pb
The S photoelectric conversion element is used naked. This PbS photoelectric conversion element detects a near infrared region having a center wavelength of 2.3 μm. In such a two-wavelength detection result,
When the output of the silicon photodiode is larger than the output of the PbS photoelectric conversion element, it can be determined that the sunlight has a peak in the visible region.

On the other hand, when the output of the PbS photoelectric conversion element is larger than the output of the silicon photodiode, 2.
It can be determined that the combustion product has a peak near 3 μm.

[0009]

By the way, in the apparatus described in Japanese Patent Application Laid-Open No. 61-32195, the photographic infrared region from visible light to near infrared is detected over a wide range. Therefore, in actual use conditions,
The possibility of excessively detecting sunlight increases.

[0010] For example, a case is assumed in which a combustible and sunlight (or reflected light thereof) are emitted from a close position. In such a case, the spectral characteristics of light have peaks in the visible region and the near-infrared region, respectively. In such an environment where sunlight and burning infrared rays coexist, when the sunlight becomes strong to some extent, the output of the silicon photodiode that detects a wide range up to the visible region exceeds the output of the PbS photoelectric conversion element. Become. In this case, there is a problem that the presence of the combustion material cannot be detected.

[0011] Therefore, in order to solve the above-mentioned problems, it is an object of the present invention to provide a fire detecting device in which the inability to detect combustion products due to the influence of sunlight is improved. And In the invention according to claim 4,
In addition to the object of claim 1, the mechanical driving part is eliminated,
It is an object of the present invention to provide a fire detection device having a highly reliable configuration.

A fifth aspect of the present invention is to provide a fire detecting apparatus using only one sensor, in addition to the object of the first aspect. A sixth aspect of the present invention is to provide a fire detecting device capable of efficiently reducing power consumption in a normal state, in addition to the object of the fifth aspect. According to a seventh aspect of the present invention, in addition to the first aspect, it is an object of the present invention to provide a fire detecting device using an infrared image sensor.

According to an eighth aspect of the present invention, in addition to the object of the first aspect, there is provided a fire detecting device capable of promptly alerting of a fire occurrence in a case where it is not necessary to judge between sunlight and a burning substance. The purpose is to:

[0014]

Means for Solving the Problems (Invention of claim 1) The invention of claim 1 receives an external light, and receives 1 to 2 μm.
m in the near-infrared region, and an infrared detector for detecting the amount of infrared in a plurality of wavelength bands in the near-infrared region. A comparison circuit compares the amount of infrared light on the wavelength side with the amount of infrared light on the short wavelength side.By comparing the comparison circuit, if the amount of infrared light on the long wavelength side is larger than the amount of infrared light on the short wavelength side, combustion will occur. The fire detecting device is provided with a notifying means for notifying the presence of an object.

Hereinafter, the principle of the first aspect of the present invention will be described. Generally, the sun is 57 million kilometers away
It can be regarded as an 80K black body light source. Therefore, sunlight reaching the ground is substantially equal to light obtained by attenuating black body radiation of 5780K by about 2E-5 times. Therefore, sunlight is based on the Wien's displacemen
t law), a spectral reflection photon characteristic with a wavelength of 0.6 μm as a peak is shown.

On the other hand, considering that the wood-based ignition temperature is 300 ° C., the temperature of the burned material in a normal living area is about 600K to 1500K. Therefore, the infrared rays generated from the combustion material show a spectral radiation photon characteristic having a peak at a peak wavelength of about 2 to 6 μm according to the Wien's equation. FIG. 1 is a diagram showing such spectral radiation photon characteristics for each temperature of blackbody radiation.

The comparison circuit of the present invention compares the "long-wavelength-side infrared ray amount" and the "short-wavelength-side infrared ray amount" in the 1-2 μm band using the detection result of the infrared ray detection section.
FIG. 2 is a diagram showing a comparison result between the irradiation photon number on the long wavelength side S2 and the irradiation photon number on the short wavelength side S1. As shown in FIG. 1 and FIG. 2, the sunlight of 5780K has an irradiation photon number of the long wavelength side S2 and the short wavelength side S1.
Than the number of irradiated photons.

On the other hand, in the case of about 600K to 1500K, the number of irradiation photons on the long wavelength side S2 becomes larger than the number of irradiation photons on the short wavelength side S1. Therefore, the notifying means of the present invention notifies the presence of a combustion substance from the comparison result of the comparison circuit only when the amount of infrared light on the long wavelength side is larger than the amount of infrared light on the short wavelength side. With such an operation, it is possible to accurately notify the presence of the combustion substance without erroneously determining the sunlight as the combustion substance.

Next, Japanese Patent Application Laid-Open No. 61-321 is cited as a conventional example.
The difference from the device described in Japanese Patent Publication No. 95 will be described. In the present invention, the two-wavelength detection band is set within a limited range of 1 to 2 μm. The 1-2 μm band has a peak wavelength of sunlight of 0.6 μm and a peak wavelength of burning infrared rays of 2-6.
Located in the middle of μm and the peak wavelength of sunlight is 0.6μ
The band does not include m.

As described above, the peak wavelength of sunlight is 0.6 μm.
By detecting a band out of the range, the possibility of excessively detecting sunlight is reduced. In particular, the spectral distribution of sunlight
In the 1 to 2 μm band, the characteristics show a gentle downward slope. On the other hand, the spectral distribution of the combustible material shows a relatively steeply rising characteristic in the band of 1 to 2 μm.

Therefore, even in an environment where sunlight and combustion infrared rays coexist, only in the 1-2 μm band,
There is little possibility that the spectral characteristics indicated by the burning infrared rays are canceled out by the spectral characteristics of sunlight. The dotted broken line shown in FIG. 2 indicates the number of irradiation photons on the long wavelength side S2 and the irradiation photons on the short wavelength side S1, assuming the worst case in which burning infrared rays and direct or reflected sunlight are mixed. It shows the result of calculating the ratio with the number.

In such a worst case, 70
Since the characteristics of the burning infrared rays are not negated for the combustion products having a temperature of 0 K or more, the presence of the combustion products can be notified without any trouble.

As described above, by selecting the band of 1 to 2 μm as the detection band, it is possible to more reliably report the presence of the combustibles. In the above description, the band on the short wavelength side is set to 1 to 1.5 μm and the band on the long wavelength side is set to 1.5 to 2 μm for simplicity. However, the present invention is not limited to this. is not. Generally, 1-2 μm
In the band, a plurality of bands in which the inclination of the spectral characteristic can be detected may be appropriately selected.

In the above description, for simplicity,
Although the case where the bandwidth on the long wavelength side and the bandwidth on the short wavelength side match has been described, it is not always necessary that they match. When the bandwidths are different, the amount of infrared light on the long wavelength side and the amount of infrared light on the short wavelength side may be compared after multiplying by a proportional coefficient for correcting the difference in bandwidth. According to a second aspect of the present invention, in the fire detecting device according to the first aspect, the plurality of wavelength bands detected by the infrared detector are in a wavelength range of 1 to 1.5 μm. And a wavelength band included in a wavelength range of 1.5 to 2 μm.

As described above, according to the second aspect of the present invention,
The amount of infrared rays is detected by dividing the wavelength band into two types of long and short wavelength bands.
Therefore, the comparison circuit uses the detection result of the amount of infrared light to determine “the amount of infrared light on the long wavelength side” and “the amount of infrared light on the short wavelength side”.
Can be directly compared. According to a third aspect of the present invention, in the fire detecting device according to the first aspect, the plurality of wavelength bands detected by the infrared detector are included in a wavelength range of 1 to 2 μm. And a total wavelength band extending above and below a wavelength of 1.5 μm, and a partial wavelength band included in the entire wavelength band and biased to a wavelength of 1.5 μm or more, and a comparison circuit, It is characterized in that, based on the ratio of the amount of infrared light in the entire wavelength band to the amount of infrared light in the partial wavelength band, the magnitude of the infrared light amount on the long wavelength side and the infrared light amount on the short wavelength side are compared.

As described above, according to the third aspect of the present invention, the amount of infrared rays is detected for the entire wavelength band. Therefore, for the entire wavelength band, a large detection level of the amount of infrared rays can be obtained, and the detection S / N can be further improved. Therefore, the comparison accuracy of the amount of infrared rays in the comparison circuit is improved, and the notification of the combustion products can be more accurately realized.

According to a fourth aspect of the present invention, in the fire detecting device according to any one of the first to third aspects, the infrared detector detects a plurality of external lights. An optical member having a spectral characteristic for dividing into wavelength bands, and a plurality of infrared sensors that individually receive the infrared light divided through the optical member and individually detect the amount of infrared light for each wavelength band. It is characterized by having it.

As described above, according to the fourth aspect of the present invention, an individual infrared sensor is used for each of a plurality of wavelength bands. Therefore, there is no need for a mechanism for mechanically driving the optical filter as in the configuration of a fifth aspect described later. Therefore, it is possible to relatively easily realize a fire detection device that has high reliability against device failure and requires no long-term maintenance.

According to a fifth aspect of the present invention, there is provided the fire detecting device according to any one of the first to third aspects, wherein the infrared detector detects a plurality of external lights. A plurality of types of optical filters having spectral characteristics for dividing into wavelength bands, a drive mechanism for arranging and replacing a plurality of types of optical filters, and sequentially receiving the passing light from the plurality of types of optical filters to be replaced and replaced, And an infrared sensor for detecting the amount of infrared rays in a plurality of wavelength bands in a time-division manner.

According to a sixth aspect of the present invention, in the fire detecting apparatus according to the fifth aspect, the driving mechanism is normally stopped and the infrared sensor is set to a predetermined infrared ray. When the amount is detected, the arrangement replacement of the plurality of optical filters is started.

Thus, in the invention according to claim 6,
The drive mechanism operates only in an emergency when a predetermined amount of infrared light is detected. Therefore, at normal times, the driving mechanism can be stopped. As a result, the life of the drive mechanism can be extended. In addition, since the drive mechanism is normally stopped, problems such as noise and power consumption caused by the drive mechanism can be improved.

According to a seventh aspect of the present invention, in the fire detecting device according to any one of the first to sixth aspects, the infrared detector detects external light. An imaging optical system for imaging, and an infrared image sensor unit that receives a light image formed through the imaging optical system and outputs an image signal corresponding to an amount of infrared light in a plurality of wavelength bands. ,
The comparing circuit compares the amount of infrared light on the long wavelength side with the amount of infrared light on the short wavelength side for each image region of the image signal output from the infrared image sensor unit, and the notification means is based on the comparison result of the comparing circuit. In addition, it is characterized in that "whether or not there is a burning substance" is notified for each image area.

Thus, in the invention according to claim 7,
An infrared image is captured using an infrared image sensor.
The comparison circuit compares the amount of infrared light for each image region (for example, each pixel or each pixel block) of the infrared image. Therefore, it is possible to notify the presence of the combustion material for each image region, and it becomes easy to detect the position of a fire spot.

(Invention according to claim 8) The invention according to claim 8 is the fire detection device according to any one of claims 1 to 7, wherein the notifying means includes an infrared detection unit. When the amount of infrared rays exceeding the upper limit of sunlight on the ground is detected, the presence of the burning matter is notified regardless of the result of the comparison circuit.

In this way, according to the invention of claim 8, when the amount of infrared rays exceeding the upper limit of the sunlight is detected, the presence of the burning matter is notified regardless of the result of the comparison circuit. Therefore, appropriate notification can be performed reliably and promptly without being affected by unnecessary determination of whether or not sunlight.

[0036]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) The first embodiment is an embodiment corresponding to claims 1, 2, 5, and 7. FIG.
FIG. 2 is a diagram illustrating an optical system according to the first embodiment. FIG.
FIG. 1 is a diagram illustrating an overall configuration of a first embodiment. 3 and 4, a disc-shaped filter 12 is rotatably arranged on the optical axis of the imaging optical system 11. This disc-shaped filter 12 is divided into two semicircular portions, and the optical filter 12a is fitted into one semicircular portion. Also,
An optical filter 12b is fitted into the other semicircular portion.

As shown in FIG. 5, the optical filter 12a is formed by forming a laminated thin film 31 composed of about 42 layers on a base material composed of silicon 30. The transmission characteristics of the optical filter 12a indicate bandpass characteristics that selectively transmit a wavelength range of 1 to 1.5 μm. on the other hand,
The optical filter 12b is, as shown in FIG.
3 is formed by forming a laminated thin film 34 composed of about 42 layers on a substrate composed of 3 layers. This optical filter 12
The transmission characteristic b indicates a bandpass characteristic that selectively transmits a wavelength range of 1.5 to 2 μm.

The optical filters 12a, 12a
b is designed according to a known procedure for designing an optical thin film. Disc type filter 12 configured in this way
The rotational force of the rotary motor 13 is transmitted to the central axis of the motor.

An infrared image sensor 14 is arranged on the back side of the disc-shaped filter 12 so as to be aligned with the imaging plane of the imaging optical system 11. As such an infrared image sensor 14, InGaAs is formed on an InP substrate or the like.
An image sensor or the like in which an s layer is formed for each pixel is used. The image signal output from the infrared image sensor 14 is amplified through a signal conversion circuit 15 and the like, and then is connected to one input terminal of a subtracter 16 and a switch circuit 17.
And one of the input terminals (A in FIG. 4). The output signal of the subtractor 16 is input to the other input terminal (B in FIG. 4) of the switch circuit 17 via the amplifier.

The output signal of the switch circuit 17 is recorded in the frame memory 19 via the A / D circuit 18. The output signal of the frame memory 19 is supplied to the D / A circuit 20.
, And is input to the other input terminal of the subtractor 16.
On the other hand, a microprocessor 24 is connected to the frame memory 19 via a system bus. Further, a control signal for controlling the rotation motor 13, the infrared image sensor 14, and the switch circuit 17 is output from the microprocessor 24.

As for the correspondence between the first and second embodiments of the present invention and the first embodiment, the infrared detecting section includes an imaging optical system 11, a disk-shaped filter 12, a rotary motor 13, and an infrared image sensor 14. , The comparison circuit corresponds to the subtractor 16, the switch circuit 17, and the frame memory 19, and the notification means corresponds to the microprocessor 24.

Further, regarding the correspondence between the invention described in claim 5 and the first embodiment, the plurality of optical filters correspond to the optical filters 12a and 12b, the driving mechanism corresponds to the rotary motor 13, and the infrared The sensor corresponds to the infrared image sensor 14.

Further, regarding the correspondence between the invention described in claim 7 and the first embodiment, the imaging optical system corresponds to the imaging optical system 11, and the infrared image sensor unit corresponds to the infrared image sensor 14. I do. Hereinafter, the operation of the first embodiment will be described. First, the microprocessor 24
Controls the rotation motor 13 to rotate the disc-shaped filter 12 15 times per second. With the rotation of the disc-shaped filter 12, immediately before the infrared image sensor 14, the optical filters 12a and 12b are alternately replaced.

Here, since the optical filter 12a has the band pass characteristic shown in FIG. 5, it selectively transmits infrared rays in the band of 1 to 1.5 μm. Also, the optical filter 12b
Has a bandpass characteristic shown in FIG.
It selectively transmits 2 μm infrared rays. FIG. 7 shows specific examples of these infrared images. Microprocessor 2
4 reads out the image signal from the infrared image sensor 14 one by one every half rotation of the disc-shaped filter 12. At this time, the infrared image in the 1 to 1.5 μm band transmitted through the optical filter 12a is output as an image signal for one frame (hereinafter, referred to as “A frame”). Optical filter 1
An infrared image in the 1.5 to 2 μm band transmitting through 2b is also output as an image signal for one frame (hereinafter, referred to as “B frame”).

Here, when reading the A frame, the microprocessor 24 switches the switch circuit 17 to the A side shown in FIG. When reading the B frame, the switch circuit 17 is switched to the B side shown in FIG. As a result, the image signal of the A frame is converted into a digital signal via the switch circuit 17 and the A / D circuit 18 and recorded in the frame memory 19.

On the other hand, the image signal of the B frame is subtracted by the subtractor 1
6 is input to one terminal. At this time, the other terminal of the subtractor 16 is supplied with an A-frame image signal read from the frame memory 19. Therefore, the subtractor 16 outputs a subtraction result obtained by subtracting the image signal of the A frame from the image signal of the B frame in pixel units. Subtractor 1
6 is output to the switch circuit 17 and the A / D circuit 1
The digital signal is converted into a digital signal with a sign via 8 and stored in the frame memory 19. Microprocessor 24
Stores the digitized subtraction result in the frame memory 1
9 and the sign of the subtraction result is determined for each pixel.

Here, the following determination is made based on the spectral distribution of blackbody radiation shown in FIGS. (1) When the subtraction result is positive, since (the amount of infrared rays in the band of 1 to 1.5 μm) <(the amount of infrared rays in the band of 1.5 to 2 μm),
It is determined that there is a burning substance. Note that in order to prevent erroneous determination due to noise, it is preferable to determine that there is a combustion substance only when the subtraction result exceeds a predetermined noise width.

(2) If the subtraction result is negative, (1 to
Since the amount of infrared light in the 1.5 μm band)> (the amount of infrared light in the 1.5 to 2 μm band), it is determined to be sunlight. The microprocessor 24 outputs a fire alarm signal to the outside when the combustion substance exists in at least one pixel by such a determination. With such an operation, in the first embodiment,
It is possible to prevent erroneous determination due to sunlight and output an accurate fire alarm.

In particular, in the first embodiment, the detection band is set to 1
~ 2 μm, the peak wavelength is 0.6 μm
The possibility of excessively detecting sunlight is low. Therefore, it is possible to further reduce the possibility of erroneously discriminating the sunlight as the combustion material. In this 1-2 μm band,
The spectral distribution of sunlight shows a gradual downward slope.
On the other hand, the spectral distribution of the combustible material shows a relatively steeply rising characteristic in the band of 1 to 2 μm.

Therefore, even in an environment where sunlight and combustion infrared rays coexist, the spectral characteristics indicated by combustion infrared rays are not canceled by the spectral characteristics of sunlight. Therefore, even in the situation where the combustion products and the sunlight are mixed, the presence of the combustion products can be reliably warned. Furthermore, in the first embodiment, two types of wavelength bands are detected in a time-division manner using a single infrared image sensor 14. Therefore, the circuit configuration can be simplified as compared with a case where a dedicated infrared image sensor is provided for each wavelength band. Also, compared to the case where a plurality of infrared image sensors are provided, there is no need to correct dark current noise unique to the sensors, differences in temperature characteristics, and the like, and accurate and stable detection results can be obtained.

In the first embodiment, the bandwidths of the two types of wavelength bands are equalized, so that the correction process based on the difference in the bandwidth is not required, and the comparison of the amount of infrared rays is performed directly and quickly. be able to. Furthermore, in the first embodiment, the infrared image sensor 14 is used to compare the amounts of infrared rays in pixel units. Therefore, it is possible to accurately determine the presence of a combustion substance for each imaging region of each pixel.

In the first embodiment, InGaAs is used.
You are using an infrared sensor. This InGaAs infrared sensor can detect infrared rays having a wavelength of 2 μm or less, and is particularly suitable for the detection band of the present invention. Also,
The InGaAs infrared sensor has the advantage of high sensitivity because it is of a quantum type. In addition, since the dark current is small, operation at room temperature is sufficiently possible, and a cooling device or the like is not required. Therefore, a cooling device can be omitted, and a small and inexpensive fire detection device can be realized.

Further, in the first embodiment, 1 to 2 μm
Since infrared light in the band is detected, glass or the like can be used as the material of the imaging optical system 11. Therefore, it is not necessary to use a special material such as silicon or germanium for the imaging optical system 11, and the fire detection device can be configured at low cost.

In the above-described first embodiment, the microprocessor 24 determines the presence of a combustible.
It is not limited to this. For example, the subtraction result of the subtractor 16 may be displayed on a monitor device that can distinguish between positive and negative. In such a configuration, the observer of the monitor device
By paying attention to the “display location where the subtraction result is positive”, the position of the combustion product can be easily specified.

In the first embodiment described above, 1 to
Although the amount of infrared light in the 1.5 μm band is compared with the amount of infrared light in the 1.5 to 2 μm band, the present invention is not limited to this wavelength band. Generally, it is sufficient that the inclination of the spectral distribution in the band of 1 to 2 μm can be detected. Therefore, a plurality of types of wavelength bands may be appropriately selected inside the band of 1 to 2 μm. Furthermore, in the above-described first embodiment, the bandwidths of the two types of wavelength bands are equal, but the bandwidths do not necessarily have to be equal. If the bandwidths are different, the amount of infrared rays may be corrected by the difference in the bandwidth.

In the first embodiment described above, the infrared image sensor 14 is used. However, the present invention is not limited to this configuration. For example, an infrared line sensor or an infrared point sensor can be used. Further, in the above-described first embodiment, the infrared image sensor 14 made of InGaAs is used.
It is not limited to this material. As a general quantum infrared sensor, a Schottky barrier diode having φb of about 0.5 to 0.7 eV can be used. For example, as such an infrared sensor, NiSi, W
A Schottky barrier diode formed of silicide such as Si, TiSi, CrSi and Si and the like can be used. These require cooling because of the high dark current. However, the operation can be sufficiently performed by electronic cooling typified by a Peltier element, not at a cryogenic temperature using liquid nitrogen. Further, the present invention is not limited to such a quantum infrared sensor, and a bolometer, a pyroelectric, dielectric, or other thermal infrared sensor may be used.

In the above-described first embodiment, an alarm signal is output when a combustion substance is detected in at least one or more pixels. However, the present invention is not limited to this. For example, an alarm signal may be output when the presence of a combustion substance is detected in several to several tens or more pixels. In addition, an alarm signal may be output when the presence of a combustion substance is detected in a plurality of adjacent pixels. In such a configuration, there is a possibility that a minute fire point may be missed, but it is possible to reliably prevent a false alarm due to image noise or the like.

Next, another embodiment will be described. (Second Embodiment) A second embodiment is defined in claims 1, 2, and 3.
This is an embodiment corresponding to the inventions described in 5 and 7. FIG.
FIG. 4 is an explanatory diagram showing a second embodiment.

In FIG. 8, an infrared image sensor 41 is arranged on an image forming plane of an image forming optical system (not shown). On the light receiving surface of the infrared image sensor 41, a filter plate 42 is installed so as to be able to vibrate. In the plane of the filter plate 42, optical filters 12a and 12b covering one row of pixels of the infrared image sensor 41 are formed every other row.

The optical filter 12a has a band pass characteristic of selectively transmitting a wavelength range of 1 to 1.5 μm as shown in FIG. On the other hand, the optical filter 12b has a bandpass characteristic of selectively transmitting a wavelength range of 1.5 to 2 μm as shown in FIG. A drive actuator 43 made of a piezoelectric element or the like is attached to the filter plate 42, and causes the filter plate 42 to slightly vibrate vertically in FIG.

On the other hand, an image signal from the infrared image sensor 41 is supplied to a switch circuit 45 via a signal conversion circuit 44.
Is input to The switch circuit 45 switches the output destination of the image signal in synchronization with the read cycle of the infrared image sensor 41. As a result, the odd frame image signal is input to one input terminal of the subtractor 46 after passing through the one frame delay circuit 47. The image signal of the even frame is directly input to the other input terminal of the subtractor 46.

The output of the subtractor 46 is supplied to the signal processing circuit 4
After the inversion process is performed on the odd-numbered column via the output 8, the output is output to the alarm 49. As for the correspondence between the first and second aspects of the invention and the second embodiment, the infrared detector corresponds to the imaging optical system, the filter plate 42, the drive actuator 43, and the infrared image sensor 41. The circuit corresponds to the subtractor 46, the switch circuit 45, the one-frame delay circuit 47, and the signal processing circuit 48, and the notification means corresponds to the alarm 49.

Further, regarding the correspondence between the invention described in claim 5 and the second embodiment, the plurality of optical filters correspond to the optical filters 12a and 12b, the driving mechanism corresponds to the driving actuator 43, and the infrared The sensor corresponds to the infrared image sensor 41. Further, regarding the correspondence between the invention described in claim 7 and the second embodiment, the imaging optical system corresponds to the imaging optical system, and the infrared image sensor unit corresponds to the infrared image sensor 41.

The operation of the second embodiment will be described below. First, the drive actuator 43 is mounted on the filter plate 4.
2 is minutely vibrated at a rate of 15 cycles per second. In synchronization with the minute vibration of the filter plate 42, the infrared image sensor 41 captures an infrared image in frame units. FIG. 8B is a diagram illustrating an arrangement of the filter plate 42 at the time of capturing an odd-numbered frame. Due to such an arrangement relationship, in the odd-numbered frame, an infrared image on the long wavelength side (1.5 to 2 μm band) is captured in the odd-numbered row, and the infrared image on the short wavelength side (1 to 1.5 μm band) is captured in the even-numbered row. It is imaged.

FIG. 8C is a diagram showing the arrangement of the filter plate 42 at the time of capturing an even-numbered frame.
With such an arrangement relationship, in the even-numbered frame, an infrared image on the long wavelength side (1.5 to 2 μm band) is captured in the even-numbered row, and the short-wavelength side (1 to 1.5 μm band) is captured in the odd-numbered row.
Is captured. The switch circuit 45 sequentially branches these odd-numbered frames and even-numbered frames. The odd frame after the branch is delayed by one frame period via the one-frame delay circuit 47. As a result, the odd frame and the even frame are input to the subtractor 46 at the same timing.

The subtracter 46 subtracts an odd frame from an even frame for each corresponding pixel, and sequentially outputs the result. The signal processing circuit 48 sequentially captures the subtraction output of the subtractor 46, outputs the subtraction output as it is for even rows, and inverts and outputs the subtraction output for odd rows. Here, the alarm 49 makes the following determination based on the spectral distribution of blackbody radiation shown in FIGS. 1 and 2.

(1) When the output result of the signal processing circuit 48 is positive, (the amount of infrared rays in the band of 1 to 1.5 μm) <(1.5
赤 外線 2 μm band), it is determined that there is a combustible and an alarm is issued. In order to prevent erroneous determination due to noise, it is preferable to determine that there is a combustion product when the output result exceeds a predetermined noise width.

(2) If the output result of the signal processing circuit 48 is negative, (the amount of infrared rays in the band of 1 to 1.5 μm)> (1.5
２2 μm band), so it is determined to be sunlight and no alarm is issued. With such an operation, in the second embodiment, the same effect as in the first embodiment can be obtained.

Also, as an effect unique to the second embodiment, the optical filter 12
Since a and 12b are exchanged, only a small space is required for moving the filter plate 42, which is suitable for downsizing the apparatus. Next, another embodiment will be described. (Third Embodiment) A third embodiment is defined by claims 1, 2, and 3.
This is an embodiment corresponding to the inventions described in Nos. 4 and 7.

FIG. 9 is an explanatory diagram showing the third embodiment. In FIG. 9, on an image forming surface of an image forming optical system (not shown),
An infrared image sensor 51 is provided. On the light receiving surface of the infrared image sensor 51, a transparent protective layer 50 is provided.
The filter plate 52 is formed via the. In the plane of the filter plate 52, optical filters 12a and 12b covering one row of pixels of the infrared image sensor 51 are formed every other row.

The optical filter 12a has a band pass characteristic of selectively transmitting a wavelength range of 1 to 1.5 μm as shown in FIG. On the other hand, the optical filter 12b has a bandpass characteristic of selectively transmitting a wavelength range of 1.5 to 2 μm as shown in FIG. An image signal read from such an infrared image sensor 51 is supplied to a comparator 54.
And the 1H delay circuit 53.
The delay output of the 1H delay circuit 53 is supplied to a comparator 54
Is input to the negative input terminal.

The comparison output of the comparator 54 is subjected to an inversion process on the odd-numbered column via the signal processing circuit 55, and then output to the alarm 56. As for the correspondence between the first and second aspects of the invention and the third embodiment, the infrared detector corresponds to the imaging optical system, the filter plate 52 and the infrared image sensor 51, and the comparison circuit corresponds to the comparator 54. , 1H delay circuit 53 and signal processing circuit 55, and the notification means corresponds to alarm 56.

Further, regarding the correspondence between the invention described in claim 4 and the third embodiment, the optical member is a filter plate 5.
2, a plurality of infrared sensors correspond to a plurality of pixel units on the infrared image sensor 51. Furthermore, regarding the correspondence between the invention described in claim 7 and the third embodiment, the imaging optical system corresponds to the imaging optical system, and the infrared image sensor unit corresponds to the infrared image sensor 51.

The operation of the third embodiment will be described below. First, the infrared image sensor 51 captures an infrared image that has passed through the filter plate 52 in frame units.
At this time, in the odd-numbered rows of the infrared image sensor 51, the imaging light flux passes through the optical filter 12a, so that an infrared image on the short wavelength side (1 to 1.5 μm band) is captured.
On the even-numbered rows of the infrared image sensor 51, the imaging light flux passes through the optical filter 12b, so that an infrared image on the long wavelength side (1.5 to 2 μm band) is captured.

The infrared image sensor 51 sequentially scans and outputs the image signals thus picked up line by line.
The 1H delay circuit 53 delays this image signal by one horizontal period. As a result, signals for two consecutive rows on the screen are input to the comparator 54 at the same timing.

The comparator 54 calculates these two consecutive
Compare rows sequentially. At this time, when the positive input exceeds the negative input, the comparator 54 outputs a high-level signal, and otherwise outputs a low-level signal. The signal processing circuit 55 sequentially takes in the comparison output of the comparator 54, and outputs the comparison output as it is when the current readout row is an even-numbered row, and inverts and outputs the comparison output when the current readout row is an odd-numbered row.

Here, the alarm 56 makes the following determination based on the spectral distribution of black body radiation shown in FIGS. (1) When the output result of the signal processing circuit 55 is at a high level, (the amount of infrared rays in the band of 1 to 1.5 μm) <(1.5 to 2
(the amount of infrared radiation in the μm band), it is determined that there is a burning substance and an alarm is issued.

(2) When the output result of the signal processing circuit 55 is at a low level, (the amount of infrared rays in the band of 1 to 1.5 μm)>
(The amount of infrared rays in the 1.5 to 2 μm band), it is determined to be sunlight, and no alarm is issued. With such an operation, in the third embodiment, the same effect as that of the first embodiment can be obtained.

Further, as an effect peculiar to the third embodiment, since a drive mechanism for the optical filters 12a and 12b is not required at all, a fire detection device which has high reliability against device failure and requires no long-term maintenance is comparatively required. It can be easily realized. In the third embodiment, the infrared image sensor 51 is used. However, the present invention is not limited to this. Generally, when it is not necessary to detect the position of a fire spot, two infrared point sensors that detect infrared rays at a single light receiving point may be used side by side.

In the third embodiment described above, infrared images of different wavelength bands are picked up in adjacent odd-numbered rows and even-numbered rows. However, the present invention is not limited to this.
For example, infrared rays may be distributed in two directions via a half mirror or a prism, and the amount of infrared rays may be detected at each distribution destination. In such a configuration, there is no deviation in the infrared detection field of view and the like, so that the amount of infrared radiation can be compared more strictly.

Next, another embodiment will be described. (Fourth Embodiment) The fourth embodiment is directed to Claims 1, 3,
This is an embodiment corresponding to the inventions described in 5 to 8. FIG.
FIG. 9 is an explanatory diagram showing a fourth embodiment.

The configuration of the fourth embodiment will be described below with reference to FIG. First, a disc-shaped filter 62 is rotatably arranged on the optical axis of the imaging optical system 61. This disc-shaped filter 62 is divided into two semicircular portions, and the optical filter 62a is fitted into one semicircular portion. Also,
An optical filter 62c is fitted into the other semicircular portion.

This optical filter 62a is similar to the optical filter 62a shown in FIG.
As shown in (1), it has a bandpass characteristic of selectively transmitting a wavelength range of 1 to 1.5 μm. On the other hand, the optical filter 62
As shown in FIG. 11 (b), c has a bandpass characteristic of selectively transmitting a wavelength range of 1 to 2 μm. The optical filters 62a and 62c can be designed according to a known optical design procedure using a computer or the like.

The disk type filter 62 constructed as described above
The rotational force of the rotary motor 63 is transmitted to the central axis of the motor.
The drive of the rotary motor 63 is controlled via a motor drive circuit 63a. An infrared image sensor 64 is disposed on the back side of the disc-shaped filter 62 so as to be aligned with the image forming plane of the image forming optical system 61. The image signal output from the infrared image sensor 64 is
After the synchronizing signal is synthesized in 5, it is displayed on the monitor device 66.

The image output terminal of the image processing circuit 65 is connected to the A / D input terminal of the microprocessor 69 and the image recording circuit 68, respectively. The image recording circuit 68 digitally stores image signals for two frames. The two control output terminals of the microprocessor 69 are connected to the alarm 70 and the motor drive circuit 63a, respectively.

The data output of the image recording circuit 68 is
It is connected to the microprocessor 69 via a data bus. In addition, regarding the correspondence between the first and eighth aspects of the present invention and the fourth embodiment, the infrared detecting section includes an imaging optical system 6.
1, a disk type filter 62, a rotary motor 63, and an infrared image sensor 64, and a comparison circuit is an image recording circuit 68.
The notification means corresponds to the alarm device 70 and the “function of controlling the alarm device 70 according to the pixel output comparison result” of the microprocessor 69.

Further, regarding the correspondence between the invention described in claim 3 and the fourth embodiment, the overall wavelength band is 1-2.
μm band, and a partial wavelength band corresponds to a 1-1.5 μm band. Regarding the correspondence between the inventions according to claims 5 and 6 and the fourth embodiment, the plurality of optical filters correspond to the optical filters 62a and 62c, and the driving mechanism is the rotating motor 63, the motor driving circuit 63a, and The infrared sensor corresponds to the infrared image sensor 64, which corresponds to “the function of controlling the motor drive circuit 63a according to the pixel output comparison result” of the microprocessor 69.

Further, regarding the correspondence between the invention described in claim 7 and the fourth embodiment, the imaging optical system corresponds to the imaging optical system 61, and the infrared image sensor unit corresponds to the infrared image sensor 64. I do. FIG. 12 is a flowchart illustrating the operation of the fourth embodiment. Hereinafter, the operation of the fourth embodiment will be described with reference to FIG.

First, when the main power is turned on, the microprocessor 69 controls the rotation motor 63 via the motor drive circuit 63a to stop the optical filter 62c immediately before the infrared image sensor 64 (S1 in FIG. 12). In this state, the infrared image sensor 64 captures an infrared image in the band of 1 to 2 μm via the optical filter 62c.

The image signal output from the infrared image sensor 64 is displayed on the monitor 66 via the image processing circuit 65. The monitor of the monitor device 66 can confirm the state of the monitoring area from the display image of the monitor device 66. Meanwhile, the microprocessor 69
Is the pixel output V currently being output from the image processing circuit 65.
s from the A / D conversion input terminal (FIG. 12S
2).

The microprocessor 69 determines whether or not the pixel output Vs exceeds the upper limit level V2 of the amount of infrared rays of sunlight (S3 in FIG. 12). Generally, the number of radiated photons in the 1-2 μm band included in sunlight is substantially equal to the number of radiated photons in the same band included in 725K blackbody radiation near the surface of the earth. Therefore, the pixel output V observed in an object having a combustion temperature somewhat higher than 725K
2 is measured in advance, and the pixel output V2 is set as a threshold value for the above determination, whereby it is possible to immediately determine that "combustion exists".

In this determination, the pixel output Vs is
When the infrared ray amount of the sunlight exceeds the upper limit level V2 (YES side of S3 in FIG. 12), the microprocessor 69 immediately determines that "combustion exists" and issues a combustion alarm via the alarm 70 (see FIG. 12). (FIG. 12S4). On the other hand, the pixel output V
s is equal to or lower than the upper limit level V2 (N in FIG. 12S3).
O), the microprocessor 69 determines that the pixel output Vs is
It is continuously determined whether or not the amount is lower than the lower limit level V1 of the amount of infrared rays that can be estimated as a combustion product (S5 in FIG. 12).

Here, when the pixel output Vs is lower than the lower limit level V1 of the amount of infrared rays that can be estimated as a burning substance (YES side in FIG. 12S5), the microprocessor 69 determines that there is no burning substance, The operation returns to step S2 in FIG. On the other hand, when the pixel output Vs is equal to or higher than the lower limit level V1 (NO in S5 in FIG. 12), the microprocessor 69 determines that "there is a possibility that a combustible substance exists", and proceeds to the following operation.

First, the microprocessor 69 commands the motor drive circuit 63a to start the rotary motor 63. The motor drive circuit 63a rotates the rotary motor 63 in synchronization with the vertical synchronization signal of the composite video signal output from the image processing circuit 65 (S6 in FIG. 12). "Infrared image of entire wavelength band (1-2 μm band)" transmitted through optical filter 62c by such motor rotation.
Is captured as an image signal for one frame (hereinafter, referred to as “C frame”). Further, an “infrared image of a partial wavelength band (1 to 1.5 μm band)” transmitted through the optical filter 62a is converted into an image signal for one subsequent frame (hereinafter, referred to as an image signal).
(Referred to as “A frame”) (FIG. 12S
7).

The image recording circuit 68 alternately takes in these C-frame and A-frame image signals and performs A / D
After the conversion, the data is recorded in two internal frame memories. The microprocessor 69 sequentially takes in the image signals of the A frame and the C frame from the image recording circuit 68 via the data bus.

Here, the microprocessor 69 executes the following determination (S8 in FIG. 12). (1) In the case of (pixel output of C frame)> (pixel output of A frame) × 2, in the band of 1 to 2 μm, the amount of infrared light on the long wavelength side exceeds the amount of infrared light on the short wavelength side.
Therefore, it can be determined from the spectral characteristics shown in FIGS. At this time, the microprocessor 69 controls the alarm 70 to warn of the occurrence of a fire (S9 in FIG. 12).

(2) In the case of (pixel output of C frame) <(pixel output of A frame) × 2, in the band of 1 to 2 μm, the amount of infrared light on the long wavelength side is less than the amount of infrared light on the short wavelength side. I have. Therefore, it can be determined as sunlight from the spectral characteristics shown in FIGS. At this time, the microprocessor 69 controls the motor drive circuit 63a to temporarily stop the rotary motor 63 (S10 in FIG. 12), and then returns the operation to step S1.

With such an operation, the fourth embodiment can obtain substantially the same effects as those of the first embodiment. In particular, the following points are given as effects unique to the fourth embodiment. First, in the fourth embodiment, the amount of infrared rays is normally detected in a wavelength band covering the entire range of 1 to 2 μm. Therefore, the detection S / N of the amount of infrared rays can be surely improved as compared with the case where the amount of infrared rays is detected only in a partial wavelength band as in the first embodiment.
Therefore, it is possible to accurately detect the burning matter from the minute burning infrared rays from a farther distance.

Further, in the fourth embodiment, the rotation motor 63 stops at the normal time. Therefore, the life of the drive mechanism such as the rotary motor 63 can be significantly extended. In addition, the problem of noise and power consumption of the rotation motor 63 can be solved by suspending the rotation motor 63 in the normal state. Further, in the fourth embodiment, a fire is immediately alerted to the infrared level exceeding the upper limit of sunlight. Therefore, it does not take much time to make unnecessary determination between sunlight and combustion infrared rays, and a fire occurrence can be alerted promptly.

In the fourth embodiment, the bandwidth between the entire wavelength band and the partial wavelength band is set at a ratio of 2: 1. However, the present invention is not limited to this. Absent.
Generally, when the ratio of the bandwidths is set to n: 1, it is determined whether the ratio of the amount of infrared rays in these bands is equal to or greater than n to determine the amount of infrared rays on the long wavelength side and the short wavelength side. Can be determined.

[0102]

As described above, according to the first aspect of the present invention, by comparing the "infrared ray amount on the long wavelength side" and the "infrared ray amount on the short wavelength side", the sunlight and the burning infrared ray are compared. Are accurately distinguished. In particular, in the invention described in claim 1,
The detection band is set within a wavelength range of 1 to 2 μm.

This 1-2 μm band is located between the peak wavelength of sunlight of 0.6 μm and the peak wavelength of burning infrared rays of 2 to 6 μm, and does not include the peak wavelength of sunlight of 0.6 μm. Therefore, there is little possibility that the sunlight is excessively detected, and the possibility that the sunlight is erroneously determined to be a combustion product can be further reduced. Further, in this 1 to 2 μm band, the spectral distribution of sunlight shows a gently falling rightward characteristic.

On the other hand, the spectral distribution of the combustion
In the m-band, the characteristic shows a steep rise to the right. Therefore, even in an environment where sunlight and burning infrared rays are mixed, only in the band of 1 to 2 μm, there is very little possibility that the spectral properties of the burning infrared rays are canceled out by the spectral properties of sunlight. Therefore, even when sunlight reflected on a metal object, a floor, a mirror, glass, or the like in a room or the like enters the detection window of the fire detection device, it is possible to reliably report the presence of the combustion material. In addition, even in the case where a fire detection device is installed outdoors where sunlight is directly radiated, it is possible to reliably detect the presence of a burning substance.

According to the second aspect of the present invention, the amount of infrared rays is detected separately for two types of long and short wavelength bands. Therefore, the comparison circuit can directly compare the “infrared ray amount on the long wavelength side” with the “infrared ray amount on the short wavelength side” directly using the detection result of the infrared ray amount. According to the third aspect of the invention, by detecting the amount of infrared rays in the entire wavelength band, the detection S / N of the amount of infrared rays can be further improved. As a result, the comparison accuracy of the comparison circuit is improved, and the notification of the combustion products can be more accurately realized.

[0106] By such an operation and effect, it is possible to notify the burning matter based on the minute burning infrared rays from farther away. According to the fourth aspect of the present invention, since an individual infrared sensor is used for each of a plurality of wavelength bands, a mechanical driving mechanism is not required. Therefore, it is possible to relatively easily realize a fire detection device or the like that has high reliability with respect to device failure and requires no long-term maintenance.

According to the present invention, a plurality of wavelength bands are detected by a single infrared sensor in a time-division manner. for that reason,
There is no need to correct detection variations and temperature characteristics of each sensor that occur when a plurality of infrared sensors are used, and an accurate and stable detection result can be obtained. According to the invention described in claim 6, the drive mechanism starts operating only when a predetermined amount of infrared light is detected.

Therefore, it is possible to suspend the drive mechanism at normal times, and it is possible to greatly extend the life of the drive mechanism. In addition, since the drive mechanism is normally stopped, problems such as noise and power consumption in the drive mechanism can be solved. According to a seventh aspect of the present invention, the amount of infrared rays is compared for each image area of the infrared image using an infrared image sensor. Therefore, it is possible to accurately notify the presence of the combustion substance for each image area.

According to the eighth aspect of the present invention, when the amount of infrared rays exceeding the upper limit of sunlight is detected, the presence of the burning matter is notified regardless of the result of the comparison circuit. By such an operation, appropriate information can be promptly and reliably executed without being influenced by the determination as to whether or not sunlight.

[Brief description of the drawings]

FIG. 1 is a diagram showing a spectral distribution characteristic of blackbody radiation.

FIG. 2 is a diagram showing a comparison of the irradiation photon numbers between the S1 region and the S2 region.

FIG. 3 is a diagram illustrating an optical system according to the first embodiment.

FIG. 4 is a diagram showing a schematic configuration of the first embodiment.

FIG. 5 is a diagram illustrating bandpass characteristics of an optical filter 12a.

FIG. 6 is a diagram illustrating bandpass characteristics of an optical filter 12b.

FIG. 7 is a diagram illustrating a difference between infrared images due to optical filters 12a and 12b.

FIG. 8 is an explanatory diagram showing a second embodiment.

FIG. 9 is an explanatory diagram showing a third embodiment.

FIG. 10 is an explanatory diagram showing a fourth embodiment.

FIG. 11 is a diagram illustrating characteristics of optical filters 62a and 62c.

FIG. 12 is a flowchart illustrating the operation of the fourth embodiment.

[Explanation of symbols]

 Reference Signs List 11 imaging optical system 12 disc-shaped filter 12a optical filter 12b optical filter 13 rotation motor 14 infrared image sensor 16 subtractor 17 switch circuit 18 A / D circuit 19 frame memory 20 D / A circuit 22 video signal processing circuit 23 monitoring device 24 Microprocessor 31 Laminated thin film 41 Infrared image sensor 42 Filter plate 43 Drive actuator 44 Signal conversion circuit 45 Switch circuit 46 Subtractor 47 1 frame delay circuit 48 Signal processing circuit 49 Alarm 50 Protective layer 51 Infrared image sensor 52 Filter plate 53 1H delay Circuit 54 Comparator 55 Signal processing circuit 56 Alarm 61 Imaging optical system 62 Disc-shaped filter 62a Optical filter 62c Optical filter 63 Rotary motor 63a Motor drive circuit 64 Infrared Mejisensa 65 image processing circuit 66 monitoring device 68 an image recording circuit 69 microprocessor 70 alarm

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI G01V 9/04 U

Claims (8)

[Claims] 1. An infrared detector for receiving external light and detecting an amount of infrared light in a plurality of wavelength bands in a near infrared region of 1 to 2 μm, and an infrared light in a plurality of wavelength bands detected by the infrared detector. Based on the amount, in a near-infrared region of 1 to 2 μm, a comparison circuit that compares “the amount of infrared light on the long wavelength side” and “the amount of infrared light on the short wavelength side”. A fire detecting device, comprising: a notifying unit for notifying the presence of a burning substance when the amount of infrared rays is larger than the amount of infrared rays on the short wavelength side. 2. The fire detection device according to claim 1, wherein the plurality of wavelength bands detected by the infrared detection unit include a wavelength band included in a wavelength range of 1 to 1.5 μm and a wavelength band of 1.5 to 2 μm. A fire detection device characterized by a wavelength band included in a wavelength range. 3. The fire detection device according to claim 1, wherein the plurality of wavelength bands detected by the infrared detection unit are included in a wavelength range of 1 to 2 μm, and extend over a wavelength of 1.5 μm. And a partial wavelength band included in the overall wavelength band and deviated to a wavelength of 1.5 μm or more, and the comparison circuit includes an infrared amount of the overall wavelength band, A fire detection device, wherein the magnitude of an infrared ray on a longer wavelength side and that on a shorter wavelength side are compared based on a ratio of an infrared ray quantity in a partial wavelength band. 4. The fire detection device according to claim 1, wherein the infrared detection unit includes an optical member having a spectral characteristic for dividing external light into the plurality of wavelength bands. A fire detecting device, comprising: a plurality of infrared sensors that individually receive infrared light separated through the optical member. 5. The fire detection device according to claim 1, wherein the infrared detection unit includes a plurality of types of spectral characteristics for dividing external light into the plurality of wavelength bands. An optical filter, a drive mechanism for arranging and exchanging the plurality of types of optical filters, and sequentially receiving light passing from the plurality of types of optical filters to be arranging and exchanging, and time-sharing the amount of infrared rays in the plurality of wavelength bands. A fire detecting device, comprising: an infrared sensor for detecting. 6. The fire detection device according to claim 5, wherein the drive mechanism is normally halted, and when the infrared sensor detects a predetermined amount of infrared light, the arrangement of the plurality of types of optical filters is exchanged. Fire detection device characterized by starting. 7. The fire detection device according to claim 1, wherein the infrared detection unit includes an imaging optical system that forms an image of external light and the imaging optical system. An infrared image sensor unit that receives a light image to be formed and outputs an image signal corresponding to the amount of infrared light in the plurality of wavelength bands, and wherein the comparison circuit outputs an image signal from the infrared image sensor unit. Comparing the amount of infrared light on the long wavelength side and the amount of infrared light on the short wavelength side for each image region of the image signal to be transmitted, and the notifying unit performs `` burning '' for each image region based on the comparison result of the comparison circuit. A fire detection device for notifying whether an object exists or not. 8. The fire detecting device according to claim 1, wherein the notifying unit detects an amount of infrared light exceeding an upper limit of sunlight on the ground in the infrared detection unit. A fire detection device for notifying the presence of a burning matter irrespective of the result of the comparison circuit.