JP7808930B2 - Detection device - Google Patents

Description

The present invention relates to a detection device for detecting smoke and/or fire.

Smoke detectors, fire alarms, and other devices are known that detect smoke in the outside air by shining light into a space into which outside air flows and detecting light scattered by smoke particles (see, for example, Patent Document 1). Also known is technology that detects smoke occurring within a surveillance area from surveillance camera footage and determines whether or not there is a fire (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 2016-20902 Japanese Patent Application Laid-Open No. 2004-104727

Smoke detectors, fire alarms, etc., installed in homes and other areas can reduce the risk of fire damage. It has been desired that such smoke detectors, fire alarms, etc. be able to accurately detect smoke or fire with a simple configuration, without the need for complex structures, complex calculations, or additional equipment such as surveillance cameras.

The present invention was made in consideration of these points, and aims to enable accurate detection of smoke and/or fire with a simple configuration.

In a first aspect of the present invention, there is provided a light source unit that emits white light including light of a first emission color, a second emission color, and a third emission color that are different from one another; a storage unit that has a wall that forms an internal space into which outside air is introduced, and the wall is colored with a color including the first emission color at the position where the white light is emitted; a first light detection unit that is disposed within the storage unit at a position not directly irradiated by the light from the light source unit and detects the intensity of the incident light of the first emission color; a second light detection unit that is disposed within the storage unit at a position not directly irradiated by the light from the light source unit and detects the intensity of the incident light of the second emission color; and a second light detection unit that is disposed within the storage unit at a position not directly irradiated by the light from the light source unit and detects the intensity of the incident light of the second emission color. The detection device includes a third light detection unit that detects the intensity of light of the third emitted color; a memory unit that, while the light source unit is irradiating the white light in a state where outside air containing smoke is not being introduced into the space, stores the light intensity detected by the first light detection unit as a first reference intensity, stores the light intensity detected by the second light detection unit as a second reference intensity, and stores the light intensity detected by the third light detection unit as a third reference intensity; and a determination unit that determines whether the outside air introduced into the storage unit contains smoke based on the difference between the light intensity detected by the first light detection unit and the first reference intensity, the difference between the light intensity detected by the second light detection unit and the second reference intensity, and the difference between the light intensity detected by the third light detection unit and the third reference intensity.

The first light emitting color, the second light emitting color, and the third light emitting color may each be any one of red, green, and blue.

The determination unit may determine whether the outside air introduced into the storage unit contains smoke in response to a change in at least one difference among the difference between the intensity of light detected by the first light detection unit and the first reference intensity, the difference between the intensity of light detected by the second light detection unit and the second reference intensity, and the difference between the intensity of light detected by the third light detection unit and the third reference intensity.

The determination unit may determine that dust is attached to the wall of the storage unit when the intensity of light detected by the first light detection unit decreases below the first reference intensity, the intensity of light detected by the second light detection unit increases above the second reference intensity, and the intensity of light detected by the third light detection unit increases above the third reference intensity.

The determination unit may determine that dust is attached to the light source unit, the first light detection unit, the second light detection unit, or the third light detection unit when the intensity of light detected by the first light detection unit decreases below the first reference intensity, the intensity of light detected by the second light detection unit decreases below the second reference intensity, and the intensity of light detected by the third light detection unit decreases below the third reference intensity.

The memory unit may further store, as a reference table, a table that associates the light intensities detected by the first light detection unit, the second light detection unit, and the third light detection unit with the types of objects when smoke generated by burning each type of object is introduced into the space, and the detection device may further include an identification unit that identifies whether smoke contained in the outside air is smoke from a burning object by comparing the light intensities detected by the first light detection unit, the second light detection unit, and the third light detection unit with the reference table.

If the identification unit determines that the smoke contained in the outside air is smoke from a burning object, it may further identify the type of burning object by comparing the intensities of light detected by the first light detection unit, the second light detection unit, and the third light detection unit with the reference table.

The detection device may include a fire determination unit that determines whether a fire has occurred based on the identification result of the identification unit, and an alarm unit that issues an alarm to the outside in response to the fire determination unit determining that a fire has occurred.

The wall of the storage unit may be colored with a predetermined color pattern at a position where the white light is irradiated, and the color pattern may be formed so that at least one of the first reference intensity, the second reference intensity, and the third reference intensity has a predetermined magnitude.

The present invention has the advantage of enabling accurate detection of smoke and/or fire with a simple configuration.

1 shows an example of the configuration of a detection device 10 according to this embodiment. 1 shows an example of a block diagram of a circuit provided on a circuit board 30 according to the present embodiment. 1 shows a cross-sectional view of the circuit board 30 and the housing portion 60 in this embodiment, and a first example of the detection result of the photodetector 50. 10A and 10B show a cross-sectional view of the circuit board 30 and the housing portion 60 in this embodiment, and a second example of the detection result of the photodetector 50. 10A and 10B show a cross-sectional view of the circuit board 30 and the housing portion 60 in this embodiment, and a third example of the detection result of the photodetector 50. 10A and 10B show a cross-sectional view of the circuit board 30 and the housing portion 60 in this embodiment, and a fourth example of the detection result of the photodetector 50.

<Configuration example of detection device 10>
FIG. 1 shows an example of the configuration of a detection device 10 according to this embodiment. FIG. 1A shows an example of a cross-sectional view of the detection device 10 taken along a plane substantially parallel to the XZ plane. FIG. 1B shows an example of a cross-sectional view of the interior of the detection device 10 taken along a plane passing through line A-A in FIG. 1A and substantially parallel to the XY plane. In this embodiment, three orthogonal axes are indicated as the X-axis, Y-axis, and Z-axis. The detection device 10 has a function of detecting smoke in the outside air and/or a function of determining whether a fire has occurred. The detection device 10 includes a main body 20, a circuit board 30, a light source unit 40, a photodetector 50, a housing unit 60, and a light-shielding plate 70.

The main body 20 is a housing made of resin, metal, or the like. The main body 20 has a base portion 22 and a cover portion 24. The base portion 22 includes an installation surface that can be installed on a ceiling surface 23 or wall of a house. The internal components of the detection device 10 are provided on the surface of the base portion 22 opposite the installation surface. In addition, the cover portion 24 is attached to the surface of the base portion 22 opposite the installation surface. In other words, the main body 20 is constructed by attaching the cover portion 24 to the base portion 22.

The cover 24 protects the internal components of the detection device 10. The cover 24 also has multiple holes (not shown) that allow outside air to pass through inside. In other words, the holes function as inlets for outside air to enter the inside of the main body 20, and also as outlets for outside air to exit the main body 20. For example, if the detection device 10 is attached to the ceiling surface 23 inside a room and smoke is generated due to a fire or other incident inside the room, the smoke will enter the main body 20 through the holes. The detection device 10 then detects the smoke that has entered the main body 20. Smoke detection by the detection device 10 will be described later.

It is desirable that the holes be formed in multiple positions on the main body 20. Furthermore, at least some of the multiple holes may function as output ports for transmitting alarm sounds and the like generated inside the main body 20 to the outside. Alarm sounds and the like will be described later.

The circuit board 30 is a board on which circuits, circuit elements, power supply circuits, etc. are mounted. For example, the circuit board 30 is equipped with a light source unit 40, a photodetector 50, and a drive circuit for operating the light source unit 40 and the photodetector 50. The circuit board 30 also includes a control unit that controls each part of the detection device 10 to perform detection operations. A housing unit 60 is also provided on the circuit board 30. The circuit board 30 is fixed to the base unit 22, for example.

The light source unit 40 emits white light including light of a first emission color, a second emission color, and a third emission color, which are different from one another. For example, the first emission color, the second emission color, and the third emission color are red, green, and blue, respectively. In this case, the light source unit 40 is a white LED having a red LED, a green LED, and a blue LED. The light source unit 40 may also be a white laser diode having a red laser diode, a green laser diode, and a blue laser diode. Alternatively, or in addition, the light source unit 40 may include an EL element.

The photodetector 50 detects the intensities of the first, second, and third emitted colors of white light emitted from the light source unit 40. The photodetector 50 detects the intensities of red, green, and blue light, for example. In this case, the photodetector 50 may be a color sensor that outputs RGB values corresponding to the intensities of the input red, green, and blue light.

As an example, the color sensor may have a red sensor with a filter and a light-receiving element that passes red light, a green sensor with a filter and a light-receiving element that passes green light, and a blue sensor with a filter and a light-receiving element that passes blue light. The color sensor may have, for example, one red sensor, one green sensor, and one blue sensor, and be configured in a band with three sensors lined up in a row. Alternatively, the color sensor may have multiple red sensors, multiple green sensors, and multiple blue sensors, with the three types of sensors arranged in a predetermined pattern.

In this embodiment, any one of the red, green, and blue sensors is referred to as the first optical detection unit. Furthermore, of the two remaining sensors, excluding the first optical detection unit from the red, green, and blue sensors, one is referred to as the second optical detection unit, and the other is referred to as the third optical detection unit. In other words, the first optical detection unit detects the intensity of light of the first emitted color, the second optical detection unit detects the intensity of light of the second emitted color, and the third optical detection unit detects the intensity of light of the third emitted color. The optical detector 50 has such a first optical detection unit, second optical detection unit, and third optical detection unit.

The housing 60 houses optical components such as the light source 40 and the photodetector 50. The housing 60 has multiple walls to reduce the noise components detected by the photodetector 50 when external light reaches the photodetector 50. The housing 60 functions as a dark box against external light, including visible light, when attached to the circuit board 30, for example. The housing 60 is made of, for example, metal or resin.

The storage unit 60 has multiple walls, including a first wall 61 and a second wall 62. The multiple walls form a space inside the storage unit 60 into which outside air is introduced. Figure 1 shows an example in which a light source unit 40 and a photodetector 50 are provided in such a space. The storage unit 60 also has a path for allowing outside air to pass inside. The multiple first walls 61 form a path that allows outside air to pass through the interior of the storage unit 60 while blocking light from outside. The structure formed by the multiple first walls 61 is known as a labyrinth structure, and a detailed description of it will be omitted here.

It is desirable that the entire storage unit 60 be colored black or the like. Furthermore, the multiple walls forming the internal space are colored in a color including the first emitted color at the positions where the white light from the light source unit 40 is irradiated. Figure 1 shows an example in which white light is irradiated onto the second wall unit 62. The second wall unit 62 faces the circuit board 30 and functions as the top plate of the storage unit 60. In this embodiment, an example is described in which the first emitted color is red, and the positions of the second wall unit 62 where the white light is irradiated are colored red.

The storage unit 60 may further be surrounded by an insect screen or the like. The insect screen may be, for example, a wire mesh, a metal with multiple through-holes, or a resin molded product. The insect screen prevents insects and the like from entering the storage unit 60 while allowing outside air to pass through.

The light-shielding plate 70 is provided in the internal space of the storage unit 60. The light-shielding plate 70 is provided between the light source unit 40 and the photodetector 50 to prevent the white light emitted from the light source unit 40 from directly entering the photodetector 50. The light-shielding plate 70 is formed, for example, from metal or resin to block the white light. It is desirable that the light-shielding plate 70 be colored, for example, black, to reduce light reflectance. By providing such a light-shielding plate 70, the first photodetector, second photodetector, and third photodetector are positioned inside the storage unit 60 in positions where they are not directly irradiated with light from the light source unit 40.

<Example of a block diagram of the circuit board 30>
2 shows an example of a block diagram of the circuit provided on the circuit board 30 according to this embodiment. The circuit board 30 is equipped with a light source unit 40, a photodetector 50, a power supply circuit 110, a memory unit 120, a control unit 130, and an alarm unit 140.

The light source unit 40 and photodetector 50 have been explained in Figure 1, so a duplicate explanation will be omitted here. In Figure 2, the element that detects the first emitted color of red is referred to as the first photodetector unit 51, the element that detects the second emitted color of green is referred to as the second photodetector unit 52, and the element that detects the third emitted color of blue is referred to as the third photodetector unit 53.

The power supply circuit 110 supplies power to the circuits, circuit elements, etc. of the detection device 10. For example, the power supply circuit 110 converts an externally input DC voltage V0 into a different DC voltage V1, stabilizes it, and supplies the converted DC voltage to the circuit elements, etc. provided on the circuit board 30. The power supply circuit 110 may also include a primary battery such as a manganese battery, or a secondary battery such as a lithium-ion battery.

The memory unit 120 stores the signal level of the detection signal detected by the photodetector 50 as a reference value when smoke is not being introduced into the internal space of the storage unit 60. For example, when the light source unit 40 is irradiating white light when smoke-containing outside air is not being introduced into the internal space of the storage unit 60, the memory unit 120 stores the light intensity detected by the first photodetector 51 as a first reference intensity, the light intensity detected by the second photodetector 52 as a second reference intensity, and the light intensity detected by the third photodetector 53 as a third reference intensity.

Since the photodetector 50 is housed inside the housing 60, it receives very little external light even when external light is irradiated onto the main body 20 of the detection device 10. Furthermore, the photodetector 50 is positioned inside the housing 60 at a position where it is not directly irradiated by light from the light source 40. As a result, when no smoke has entered the housing 60, the second photodetector 52 and the third photodetector 53 receive very little light from the light source 40, even if the light source 40 irradiates white light into the housing 60.

On the other hand, the second wall portion 62 of the storage portion 60 is colored with the first emission color, and because it is irradiated with light from the light source portion 40, the light of the first emission color from the light source portion 40 is reflected. Therefore, even if no smoke has entered the storage portion 60, when the light source portion 40 irradiates the interior of the storage portion 60 with white light, the first light detection portion 51 receives a portion of the light of the first emission color contained in the white light. As a result, the first reference intensity is greater than the second reference intensity and the third reference intensity. The memory portion 120 stores the values of the first reference intensity, the second reference intensity, and the third reference intensity.

The memory unit 120 may further store, as a reference table, a table that associates the light intensity detected by the first light detection unit 51, the second light detection unit 52, and the third light detection unit 53 with the type of object when smoke generated by burning each type of object is introduced into a space. An example of an object is a material contained in an object that is predicted to burn if a fire breaks out in the room where the detection device 10 is installed. An example of an object is an object that generates smoke through combustion, even if a fire does not break out in the room where the detection device 10 is installed. Examples of objects include paper, wood, cotton, resin, electrical wires, tobacco, cigars, cooking ingredients, etc.

The storage unit 120 may store intermediate data, calculation results, thresholds, reference values, parameters, etc. that are generated (or used) by the detection device 10 during its operation. The storage unit 120 may also provide the stored data to the requesting party in response to a request from each component within the detection device 10.

For example, when a computer functions as the control unit 130, the storage unit 120 may store information such as an OS (Operating System) and programs that enable the computer to function. The storage unit 120 may also store various information including databases that are referenced when the programs are executed. For example, the computer functions as the control unit 130 by executing the programs stored in the storage unit 120.

The storage unit 120 includes, for example, ROM (Read Only Memory) that stores various programs and tables executed by the computer, etc., and RAM (Random Access Memory) that serves as a working area. The storage unit 120 may also include large-capacity storage devices such as HDDs (Hard Disk Drives) and/or SSDs (Solid State Drives).

The control unit 130 controls each unit of the detection device 10 to determine whether the outside air that has entered the internal space of the storage unit 60 contains smoke. The control unit 130 may also determine whether a fire has occurred near the detection device 10. The control unit 130 has a determination unit 131, an identification unit 132, and a fire determination unit 133.

The determination unit 131 determines whether smoke is contained in the outside air introduced into the storage unit 60 based on the difference between the intensity of light detected by the first light detection unit 51 and the first reference intensity, the difference between the intensity of light detected by the second light detection unit 52 and the second reference intensity, and the difference between the intensity of light detected by the third light detection unit 53 and the third reference intensity. Here, the difference between the intensity of light detected by the first light detection unit 51 and the first reference intensity is referred to as the first intensity difference, the difference between the intensity of light detected by the second light detection unit 52 and the second reference intensity is referred to as the second intensity difference, and the difference between the intensity of light detected by the third light detection unit 53 and the third reference intensity is referred to as the third intensity difference.

The determination unit 131 may also determine whether smoke is contained in the outside air introduced into the storage unit 60 based on the ratio of the intensity of light detected by the first light detection unit 51 to the first reference intensity, the ratio of the intensity of light detected by the second light detection unit 52 to the second reference intensity, and the ratio of the intensity of light detected by the third light detection unit 53 to the third reference intensity. Here, the difference between the intensity of light detected by the first light detection unit 51 and the first reference intensity is defined as the first intensity ratio, the difference between the intensity of light detected by the second light detection unit 52 and the second reference intensity is defined as the second intensity ratio, and the difference between the intensity of light detected by the third light detection unit 53 and the third reference intensity is defined as the third intensity ratio.

If no smoke enters the storage unit 60, there is almost no change in the first intensity difference, second intensity difference, and third intensity difference. Therefore, the determination unit 131 determines whether or not smoke is contained in the outside air introduced into the storage unit 60, for example, in response to a change in at least one of the first intensity difference, second intensity difference, and third intensity difference. Alternatively, the determination unit 131 may determine whether or not smoke is contained in the outside air introduced into the storage unit 60 in response to a change in at least one of the first intensity ratio, second intensity ratio, and third intensity ratio. Alternatively, the determination unit 131 may perform the determination operation every time a predetermined time period has elapsed.

The identification unit 132 compares the light intensities detected by the first light detection unit 51, the second light detection unit 52, and the third light detection unit 53 with a reference table to determine whether the smoke contained in the outside air is smoke from a burning object. The identification unit 132 may further identify the color of the smoke and/or the type of object being burned.

For example, the identification unit 132 may identify whether the smoke contained in the outside air is smoke caused by a burning material in response to the determination unit 131 determining that the outside air contains smoke. Alternatively, the identification unit 132 may identify whether the smoke contained in the outside air is smoke caused by a burning material in response to a change in at least one intensity difference among the first intensity difference, the second intensity difference, and the third intensity difference. Alternatively, the determination unit 131 may identify whether the smoke contained in the outside air is smoke caused by a burning material in response to a change in at least one intensity ratio among the first intensity ratio, the second intensity ratio, and the third intensity ratio. Alternatively, the identification unit 132 may perform the identification operation every time a predetermined time period has elapsed.

The fire determination unit 133 determines whether or not a fire has occurred based on the identification result of the identification unit 132. For example, the fire determination unit 133 determines that a fire has occurred if the type of object identified by the identification unit 132 is a type of object that is predicted to burn in a fire. Furthermore, the fire determination unit 133 determines that a fire has not occurred if the type of object identified by the identification unit 132 is an object that will generate smoke due to combustion or the like even if a fire does not occur. If the fire determination unit 133 determines that a fire has occurred, it supplies a control signal to the alarm unit 140 to control the alarm unit 140.

The alarm unit 140 issues an external alarm in response to the fire detection unit 133 determining that a fire has occurred. The alarm unit 140 includes an alarm drive circuit 141, a speaker 142, and an indicator light 143. The alarm drive circuit 141 drives the speaker 142 and the indicator light 143 in response to a control signal. When the detection device 10 operates as a smoke detector, the control unit 130 supplies a control signal to the alarm unit 140 in response to the detection of smoke for controlling the alarm unit 140. The alarm drive circuit 141 may drive the speaker 142 and the indicator light 143 to issue alarms corresponding to the detection of smoke and the detection of a fire, respectively.

Note that, although the alarm unit 140 shown in FIG. 2 includes a speaker 142, this is not limiting. The alarm unit 140 may include a buzzer or the like instead of the speaker 142, or alternatively, the speaker 142 may not be included. The alarm unit 140 may also notify the outside when smoke or fire is detected. In this case, it is desirable that the alarm unit 140 is connected to the outside via a network or the like.

As described above, the detection device 10 according to this embodiment detects smoke and/or fire based on the difference between the detection result of the photodetector 50 when no smoke is introduced and the detection result of the photodetector 50 when outside air is introduced. This detection operation by the control unit 130 of the detection device 10 will now be described.

<Example of initial state of detection signal>
FIG. 3 shows a cross-sectional view of the circuit board 30 and the accommodation section 60 in this embodiment, and a first example of the detection result of the photodetector 50. FIG. 3 shows an example of the initial state of the detection signal of the photodetector 50. FIG. 3(A) shows the accommodation section 60 in a state where no smoke has been introduced into the internal space. FIG. 3(B) shows the concept of the detection result output by the photodetector 50 in the state of FIG. 3(A). The vertical axis of FIG. 3(B) indicates the signal level of the detection signal output by the photodetector 50. The horizontal axis of FIG. 3(B) is marked with "R" indicating the detection signal of the first photodetector 51, "G" indicating the detection signal of the second photodetector 52, and "B" indicating the detection signal of the third photodetector 53.

As already mentioned, the second wall portion 62 is colored with the first emission color, and therefore light of the first emission color from the light source portion 40 is reflected by the second wall portion 62. Therefore, the first light detection portion 51 detects a certain amount of light of the first emission color even in the initial state. In this way, the signal level of the detection signal output by the first light detection portion 51 is the first reference intensity.

Of the light from the light source unit 40, most of the light of the second and third emitted colors is absorbed by the second wall unit 62, and the remaining portion is reflected. Therefore, the signal levels detected by the second light detection unit 52 and the third light detection unit 53 are lower than the first reference intensity. In this way, the signal level of the detection signal output by the second light detection unit 52 is the second reference intensity, and the signal level of the detection signal output by the third light detection unit 53 is the third reference intensity. The memory unit 120 stores the values of these first, second, and third reference intensities.

<Example of a state in which smoke has entered the storage unit 60>
FIG. 4 shows a cross-sectional view of the circuit board 30 and the housing 60 in this embodiment, and a second example of the detection results of the photodetector 50. FIG. 4(A) shows a state in which smoke has entered the internal space of the housing 60. FIG. 4(B) shows the concept of the detection results output by the photodetector 50 in the state shown in FIG. 4(A). In this case, the light from the light source 40 is scattered by smoke particles. The larger the size of the smoke particles and the greater the number of smoke particles, the greater the scattered light component of the light from the light source 40. Note that when smoke particles become as small as the wavelength of light, light with short wavelengths, such as blue and ultraviolet, tends to be scattered more than light with long wavelengths, such as red and infrared. Therefore, the signal level of the signal detected by the corresponding photodetector may differ depending on the wavelength of the light of each emitted color and the particle size of the smoke particles.

As described above, light of the first emitted color is scattered by smoke particles, while smoke that has entered the storage unit 60 casts a shadow, reducing the light reflected by the second wall portion 62 of the storage unit 60. Therefore, the signal level detected by the first light detection unit 51 may increase or decrease depending on factors such as the smoke particle size, smoke concentration (amount, density), and the area of the second wall portion 62 colored with the first emitted color. Figure 4(B) shows an example in which the signal level detected by the first light detection unit 51 is greater than the initial first reference intensity. Note that the area of the second wall portion 62 colored with the first emitted color may be designed and adjusted in advance so that the signal level detected by the first light detection unit 51 increases from the initial state when smoke enters the storage unit 60.

As described above, the light of the second and third emitted colors is scattered by smoke particles. Furthermore, since the light of the second and third emitted colors is hardly reflected by the second wall portion 62, even if smoke that has entered the storage portion 60 casts a shadow, there is almost no effect on the signal level detected by the light detection portion. Therefore, the signal levels detected by the second light detection portion 52 and the third light detection portion 53 are both greater than the reference intensity in the initial state.

The determination unit 131 determines that the outside air introduced into the storage unit 60 contains smoke when the intensity of light detected by the first light detection unit 51 increases above the first reference intensity, the intensity of light detected by the second light detection unit 52 increases above the second reference intensity, and the intensity of light detected by the third light detection unit 53 increases above the third reference intensity. This allows the detection device 10 to detect that smoke is occurring in the room in which the detection device 10 is installed, etc.

<Example of State in Which Dust Adheres to the Second Wall 62 of the Storage Section 60>
5A and 5B show cross-sectional views of the circuit board 30 and the housing 60 in this embodiment, and a third example of the detection results of the photodetector 50. Fig. 5A shows a state in which dust has adhered to the second wall 62 of the housing 60. Fig. 5B shows the concept of the detection results output by the photodetector 50 in the state shown in Fig. 5A. In this case, the adhered dust reduces the amount of light of the first emitted color reflected and scattered by the second wall 62, so the signal level detected by the first photodetector 51 becomes smaller than the reference intensity in the initial state.

In addition, the adhering dust reduces the amount of light of the second and third emitted colors that reaches and is absorbed by the second wall portion 62. Furthermore, the amount of light of the second and third emitted colors that is reflected and scattered by the adhering dust increases. Therefore, the signal levels detected by the second light detection unit 52 and the third light detection unit 53 become greater than the reference intensity in the initial state.

The determination unit 131 then determines that dust has adhered to the wall of the storage unit 60 when the intensity of light detected by the first light detection unit 51 decreases below the first reference intensity, the intensity of light detected by the second light detection unit 52 increases above the second reference intensity, and the intensity of light detected by the third light detection unit 53 increases above the third reference intensity. This allows the detection device 10 to reduce the rate at which smoke is mistakenly detected when dust has adhered inside the storage unit 60, and to accurately detect the occurrence of dirt on the storage unit 60.

In addition, dust or other particles may adhere to the light-emitting surface of the light source unit 40 or the light-receiving surface of the photodetector 50. In this case, the signal levels detected by the first photodetector unit 51, the second photodetector unit 52, and the third photodetector unit 53 will all be smaller than the reference intensity in the initial state.

The determination unit 131 then determines that dust is attached to the light source unit 40, the first light detection unit 51, the second light detection unit 52, or the third light detection unit 53 when the intensity of light detected by the first light detection unit is reduced below the first reference intensity, the intensity of light detected by the second light detection unit is reduced below the second reference intensity, or the intensity of light detected by the third light detection unit is reduced below the third reference intensity. This allows the detection device 10 to accurately detect the generation of smoke by reducing the rate of false detections when dust is attached to the light source unit 40 or the light detector 50.

As described above, the detection device 10 according to this embodiment can accurately detect the occurrence of smoke. However, if the detection device 10 immediately determines that a fire has occurred in response to the detection of smoke occurrence, this may result in a false detection. For example, if the detection device 10 detects smoke from cooking (meat, fish, etc.), water vapor, cigarettes, etc., and determines that a fire has occurred, this will result in a false detection. Therefore, the identification unit 132 identifies whether the detected smoke is smoke from a burning material.

<Example of a state in which smoke of various colors has entered the storage section 60>
6A and 6B show cross-sectional views of the circuit board 30 and the housing 60 according to this embodiment, and a fourth example of the detection results of the photodetector 50. FIG. 6A shows a state in which smoke has entered the internal space of the housing 60. FIG. 6B shows a conceptual diagram of the detection results output by the photodetector 50 in the state shown in FIG. 6A. The color of the smoke may vary depending on the source of the smoke. Since the photodetector 50 detects scattered light of three different emitted colors, the detection signals of the three emitted colors have different signal levels depending on the color of the smoke.

For example, when paper, cotton, etc. burns, smoke close to white is produced. Because white smoke reflects and scatters light of the three emitted colors, the signal levels detected by the first light detection unit 51, second light detection unit 52, and third light detection unit 53 tend to increase. Furthermore, when resin, electrical wire, etc. burns, smoke close to black is produced. Because black smoke absorbs light of the three emitted colors, the signal levels detected by the first light detection unit 51, second light detection unit 52, and third light detection unit 53 tend to decrease. In this way, the light detector 50 outputs different detection results depending on whether the smoke is produced when an object is not burning, when an object is burning, or the type of object being burned.

The identification unit 132 can therefore identify whether the smoke contained in the outside air is smoke from a burning object by comparing the detection results of the first light detection unit 51, the second light detection unit 52, and the third light detection unit 53 with the reference table stored in the memory unit 120. Since the reference table associates the type of burning object with the detection results of the light detector 50, if the identification unit 132 identifies that the smoke contained in the outside air is smoke from a burning object, it can further identify the type of burning object.

This allows the fire detection unit 133 to determine, for example, whether the smoke is caused by cooking or a fire. Furthermore, the fire detection unit 133 can determine whether a fire has occurred, for example, by using the correspondence between the type of burning material and whether a fire has occurred. It is desirable that the correspondence between the type of burning material and whether a fire has occurred is stored in advance in the memory unit 120. Furthermore, the reference table stored in the memory unit 120 may further include such correspondence.

Alternatively, or in addition, the identification unit 132 may identify the color of smoke contained in the outside air based on the difference between the intensity of light detected by the first light detection unit 51 and the first reference intensity, the difference between the intensity of light detected by the second light detection unit 52 and the second reference intensity, and the difference between the intensity of light detected by the third light detection unit 53 and the third reference intensity. In this case, the identification unit 132 identifies the color of smoke based on the correspondence between the color of smoke and the first intensity difference, the second intensity difference, and the third intensity difference. Note that it is preferable that the correspondence between the color of smoke and the first intensity difference, the second intensity difference, and the third intensity difference be stored in the memory unit 120.

The identification unit 132 may also identify the color of smoke contained in the outside air based on the first intensity ratio, the second intensity ratio, and the third intensity ratio. In this case, the identification unit 132 identifies the color of smoke based on the correspondence between the color of smoke and the first intensity ratio, the second intensity ratio, and the third intensity ratio. It is preferable that the correspondence between the color of smoke and the first intensity ratio, the second intensity ratio, and the third intensity ratio be stored in the memory unit 120.

In this case, the fire detection unit 133 may determine whether or not a fire has occurred based on the color of the smoke identified by the identification unit 132. In this case, the fire detection unit 133 uses a correspondence relationship between the color of the smoke and whether or not a fire has occurred. It is desirable that such a correspondence relationship be stored in advance in the memory unit 120.

As described above, the detection device 10 according to this embodiment can accurately detect the occurrence of a fire. While the above detection device 10 has been described with an example in which the light source unit 40 emits white light containing light of three luminous colors, red, green, and blue, this is not limitative. Since the scattering and reflection characteristics of smoke differ depending on the luminous color, the combination of red, green, and blue is not required as long as the light source unit 40 contains three different luminous colors. Furthermore, the light source unit 40 may contain four or more luminous colors, in which case the photodetector 50 may also be configured to detect light of four or more corresponding luminous colors.

In the above description of the detection device 10 according to this embodiment, an example has been described in which the second wall portion 62 of the storage portion 60 is colored in a color including the first emitted color at the position where the white light from the light source portion 40 is irradiated, but this is not limited to this. Alternatively, the position where the white light is irradiated may be colored in a color including the second emitted color, or in a color including the third emitted color. Note that coloring may be achieved by painting or applying a sticker or the like. Furthermore, if the storage portion 60 is made of resin, the molded color of part of the resin may include the emitted color.

Furthermore, the position on the second wall 62 of the storage unit 60 where the white light is irradiated may be colored with a predetermined color pattern. For example, part of the area of the second wall 62 where the white light is irradiated may be colored with a color that includes the first emitting color. The area of the second wall 62 colored with the first emitting color reflects light of the first emitting color, so changing the area of that area changes the magnitude of the reference intensity in the initial state.

It is therefore desirable to determine in advance the size of the area to be colored with the first emitted color, the coloring pattern, etc., during the design, manufacturing, calibration, etc. stages of the detection device 10. In this case, it is desirable that the coloring pattern be formed so that at least one of the first reference intensity, second reference intensity, and third reference intensity has a predetermined magnitude. By adjusting the magnitude of the reference intensity in advance in this way, the detection device 10 can, for example, detect smoke and fire within an appropriate range in which the detection sensitivity of the photodetector 50 is linear.

Note that if the detected smoke is black or close to black, the signal level detected by the first optical detection unit 51, second optical detection unit 52, and third optical detection unit 53 will decrease. In this case, the closer the smoke is to black, the closer the signal level will be to 0, which may result in a poor S/N ratio.

Therefore, if the signal levels detected by the first optical detection unit 51, the second optical detection unit 52, and the third optical detection unit 53 all fall below the threshold, the control unit 130 may control the circuit that drives the light source unit 40 to increase the signal level of the detection signal output by the optical detector 50. In this case, the control unit 130 increases the intensity of the white light emitted by the light source unit 40. This allows the detection device 10 to improve the S/N ratio and detect black or nearly black smoke. Note that if an amplifier is implemented downstream of the optical detector 50, the control unit 130 may control the amplifier to increase the amplification factor of the amplifier.

Note that even if the control unit 130 controls the drive circuit to increase the intensity of the white light from the light source unit 40, the signal level of the detection signal output by the photodetector 50 may remain reduced. In this case, the control unit 130 may determine that the light source unit 40 has failed. For example, if the control unit 130 determines that the light source unit 40 has failed, it supplies a corresponding control signal to the alarm unit 140. This allows the alarm unit 140 to issue an alarm indicating a failure in the light source unit 40, allowing the user of the detection device 10 to quickly become aware of a failure in the detection device 10.

In the above description of the detection device 10 according to this embodiment, the control unit 130 includes the determination unit 131 and the identification unit 132, but this is not limited to this. The control unit 130 may also include either the determination unit 131 or the identification unit 132.

The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and alterations are possible within the spirit of the invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of new embodiments resulting from the combination will also have the effects of the original embodiments.

10 Detecting device 20 Main body 22 Base portion 23 Ceiling surface 24 Cover portion 30 Circuit board 40 Light source portion 50 Photodetector 51 First photodetector portion 52 Second photodetector portion 53 Third photodetector portion 60 Storage portion 61 First wall portion 62 Second wall portion 70 Light shielding plate 110 Power supply circuit 120 Memory portion 130 Control portion 131 Determination portion 132 Identification portion 133 Fire determination portion 140 Alarm portion 141 Alarm drive circuit 142 Speaker 143 Indicator light

Claims (9)

a light source unit that emits white light including light of a first emission color, a second emission color, and a third emission color that are different from one another;
a container having a wall portion that forms an internal space into which outside air is introduced, and at least a part of the wall portion that is irradiated with the white light is colored with the first emission color;
a first light detection unit disposed inside the housing unit at a position where reflected light of the light source unit irradiated onto a colored portion of the wall unit is incident and where the light of the light source unit is not directly irradiated, and which detects the intensity of the incident light of the first emitted color;
a second light detection unit disposed inside the housing unit at a position where reflected light of the light source unit irradiated onto a colored portion of the wall unit is incident and where the light of the light source unit is not directly irradiated, and which detects the intensity of the incident light of the second emitted color;
a third light detection unit disposed inside the housing unit at a position where reflected light of the light source unit irradiated onto a colored portion of the wall unit is incident and where the light of the light source unit is not directly irradiated, and which detects the intensity of the incident light of the third emitted color;
a storage unit that stores the intensity of light detected by the first light detection unit as a first reference intensity, the intensity of light detected by the second light detection unit as a second reference intensity, and the intensity of light detected by the third light detection unit as a third reference intensity while the light source unit is irradiating the white light in a state where outside air containing smoke is not being introduced into the space;
a determination unit that determines whether or not smoke is contained in the outside air introduced into the storage unit based on a difference between the intensity of light detected by the first light detection unit and the first reference intensity, a difference between the intensity of light detected by the second light detection unit and the second reference intensity, and a difference between the intensity of light detected by the third light detection unit and the third reference intensity ;
Equipped with
an area of the wall portion colored with the first luminous color is an area at which a signal level detected by the first light detection unit in a state where white smoke has entered the storage portion increases compared to an initial state where white smoke has not been introduced into the storage portion;
The determination unit determines that the outside air introduced into the wall portion of the storage unit contains smoke in response to the intensity of light detected by the first light detection unit increasing above the first reference intensity, the intensity of light detected by the second light detection unit increasing above the second reference intensity, and the intensity of light detected by the third light detection unit increasing above the third reference intensity . The detection device of claim 1, wherein the first emitted color, the second emitted color, and the third emitted color are each one of red, green, and blue. The detection device described in claim 1 or 2, wherein the determination unit determines whether the outside air introduced into the storage unit contains smoke in response to a change in at least one difference among the difference between the intensity of light detected by the first light detection unit and the first reference intensity, the difference between the intensity of light detected by the second light detection unit and the second reference intensity, and the difference between the intensity of light detected by the third light detection unit and the third reference intensity. The detection device described in any one of claims 1 to 3, wherein the determination unit determines that dust is attached to the wall of the storage unit when the intensity of light detected by the first light detection unit decreases below the first reference intensity, the intensity of light detected by the second light detection unit increases above the second reference intensity, and the intensity of light detected by the third light detection unit increases above the third reference intensity. The detection device described in any one of claims 1 to 4, wherein the determination unit determines that dust is attached to the light source unit, the first light detection unit, the second light detection unit, or the third light detection unit when the intensity of light detected by the first light detection unit decreases below the first reference intensity, the intensity of light detected by the second light detection unit decreases below the second reference intensity, and the intensity of light detected by the third light detection unit decreases below the third reference intensity. the storage unit further stores, as a reference table, a table in which, when smoke generated by burning each material contained in an object that is predicted to burn in the event of a fire is introduced into the space, the intensities of light detected by the first light detection unit, the second light detection unit, and the third light detection unit correspond to the materials contained in the object that are predicted to burn in the event of a fire;
and a determination unit that determines whether smoke contained in the outside air is smoke from a combustion object that is predicted to combust by comparing the intensities of light detected by the first light detection unit, the second light detection unit, and the third light detection unit with the reference table.
6. A detection device according to any one of claims 1 to 5. The detection device described in claim 6, wherein, when the identification unit identifies that the smoke contained in the outside air is smoke from the burning material, the identification unit further identifies the material contained in the burning material by comparing the intensities of light detected by the first light detection unit, the second light detection unit, and the third light detection unit with the reference table. a fire determination unit that determines whether or not a fire has occurred based on the identification result of the identification unit;
The detection device according to claim 6 or 7, further comprising: an alarm unit that issues an alarm to an outside in response to the fire determination unit determining that a fire has occurred. a wall portion of the storage portion where the white light is irradiated is colored with a predetermined color pattern;
the colored pattern is formed so that at least one of the first reference intensity, the second reference intensity, and the third reference intensity has a predetermined magnitude.
9. A detection device according to any one of claims 1 to 8.