Smoke detector

Abstract

The present invention provides a two-light-reception smoke detecting device that is easier to miniaturize than with the prior art. A two-light-reception smoke detecting device 1 according to an embodiment of the present invention comprises: a light emitting unit 94 that emits polarized light; a first light receiving unit 95 having a first light reception axis C intersecting a light emission axis B of the light emitting unit 94; a second light receiving unit 96 having a second light reception axis D that intersects the light emission axis B and that is different from the first light reception axis C; a processor 97 which determines a type of smoke in air on the basis of a signal output by the first light receiving unit 95 and a signal output by the second light receiving unit 96 when the light emitting unit 94 emits light; and a shielding member 13 which accommodates the first light receiving unit 95 and which shields light directed toward the first light receiving unit 95 in a direction intersecting the first light reception axis C. The first light reception axis C is inclined with respect to a perpendicular direction of a first light receiving unit electronic circuit board 11. The shielding member 13 also serves as an attachment member enabling the first light receiving unit 95 to be attached to the first light receiving unit electronic circuit board 11 in an inclined state.

Description

[Technical Field]

[0001] The present invention relates to a device for detecting smoke. [Background technology]

[0002] There are smoke detection devices that detect the occurrence of smoke in a monitored space by detecting smoke contained in the monitored space. One type of smoke detection device is called a photoelectric type. Photoelectric smoke detection devices detect smoke based on a signal generated when the light receiving unit receives light that is emitted from the light emitting unit and reflected by smoke particles in the air that flows from the outside into a container that houses the light emitting unit and the light receiving unit.

[0003] Another type of photoelectric smoke detector is the dual-light-receiving type, which emits polarized light in the direction of the light-emitting axis from the light-emitting element and determines the type of smoke in the air based on the signals generated by two light-receiving elements with light-receiving axes that intersect the light-emitting axis from different directions.

[0004] Patent Document 1, for example, is a patent document disclosing a two-light receiving smoke detector. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-181507 Summary of the Invention [Problem to be solved by the invention]

[0006] FIG. 11 is a diagram showing a schematic configuration of a two-light receiving smoke detection device 9 according to the prior art. In FIG. 11, components unrelated to the features of the present invention are omitted from the illustration. FIG. 11(A) is a plan view of the smoke detection device 9 with the lid of the container removed. FIG. 11(B) is a cross-sectional view of the smoke detection device 9 shown by the dashed line in FIG. 11(A) as viewed in the direction of arrow A. However, FIG. 11(B) shows the cross-section of the smoke detection device 9 with the lid of the container attached.

[0007] In the following description, for convenience, the direction in which the paper on which FIG. 11(A) is drawn extends is taken as the horizontal plane.

[0008] The smoke detection device 9 includes an electronic circuit board 91 for the light-emitting unit, an electronic circuit board 92 for the first light-receiving unit, an electronic circuit board 93 for the second light-receiving unit, a light-emitting unit 94, a first light-receiving unit 95, a second light-receiving unit 96, a processor 97, and a container 98.

[0009] The light-emitting portion electronic circuit board 91 is an electronic circuit board that is arranged to stand upright perpendicular to a horizontal plane. A light-emitting portion 94 is arranged on the light-emitting portion electronic circuit board 91.

[0010] The first light receiving unit electronic circuit board 92 is an electronic circuit board arranged on a plane inclined with respect to the horizontal plane. A first light receiving unit 95 and a processor 97 are arranged on the first light receiving unit electronic circuit board 92.

[0011] The second light receiving unit electronic circuit board 93 is an electronic circuit board that is arranged to stand perpendicular to a horizontal plane. A second light receiving unit 96 is arranged on the second light receiving unit electronic circuit board 93.

[0012] The processor 97 may be disposed on an electronic circuit board other than the first light receiving section electronic circuit board 92 (for example, the light emitting section electronic circuit board 91 or the second light receiving section electronic circuit board 93).

[0013] The light emitting unit 94 emits polarized light in the direction of the light emitting axis (hereinafter referred to as "light emitting axis B") indicated by arrow B in Fig. 11. For example, if the polarized light emitted by the light emitting unit 94 is linearly polarized light, the direction of the line is perpendicular to the horizontal plane, and if the polarized light emitted by the light emitting unit 94 is elliptically polarized light, the direction of the major axis of the ellipse is perpendicular to the horizontal plane.

[0014] The first light receiving unit 95 receives light directed in the direction of a first light receiving axis (hereinafter referred to as "first light receiving axis C") indicated by arrow C in Figure 11(B) and generates a signal indicating the intensity of the received light. The first light receiving axis C intersects with the light emitting axis B at a predetermined angle within a vertical plane (a plane perpendicular to the horizontal plane) that includes the light emitting axis B. The first light receiving unit electronic circuit board 92 is disposed in a position perpendicular to the first light receiving axis C.

[0015] The second light receiving unit 96 receives light directed in the direction of a second light receiving axis (hereinafter referred to as "second light receiving axis D") indicated by arrow D in Figure 11(A) and generates a signal indicating the intensity of the received light. The second light receiving axis D is an axis in a different direction from the first light receiving axis C and intersects with the light emitting axis B at a predetermined angle within a horizontal plane including the light emitting axis B.

[0016] The angle between the light-emitting axis B and the first light-receiving axis C and the angle between the light-emitting axis B and the second light-receiving axis D may be the same or different.

[0017] The processor 97 is a calculation device that processes data and serves as a smoke determination unit that determines the type of smoke in the air based on the signal generated by the first light receiving unit 95 when the light emitting unit 94 emits light and the signal generated by the second light receiving unit 96 when the light emitting unit 94 emits light. For example, the processor 97 determines the type of smoke in the air that flows into the container 98 from outside the container 98 based on the result of comparing the ratio of the amplitude value of the signal generated by the second light receiving unit 96 when the light emitting unit 94 emits light to the amplitude value of the signal generated by the first light receiving unit 95 when the light emitting unit 94 emits light with a predetermined threshold.

[0018] The container 98 houses components of the smoke detection device 9, including the light-emitting unit 94, the first light-receiving unit 95, and the second light-receiving unit 96. The container 98 has an inlet H1 for air flowing in from the outside and an outlet H2 for air flowing out to the outside.

[0019] In the smoke detection device 9 according to the above-mentioned conventional technology, the electronic circuit board 92 for the first light receiving unit is arranged so as to be inclined with respect to the horizontal plane, and the electronic circuit board 93 for the second light receiving unit is arranged so as to be upright with respect to the horizontal plane, so that the length in the vertical direction (the longitudinal direction in Figure 11 (B)) is long, and the size of the smoke detection device 9 is large.

[0020] In view of the above circumstances, the present invention provides a two-light receiving smoke detector that can be more easily miniaturized than conventional techniques. [Means for solving the problem]

[0021] In order to solve the above problems, the present invention proposes a smoke detection device comprising: a light-emitting unit that emits light; a first light-receiving unit that has a first light-receiving axis that intersects with the light-emitting axis of the light-emitting unit; a first electronic circuit board on which the first light-receiving unit is arranged; a second light-receiving unit that has a second light-receiving axis that intersects with the light-emitting axis of the light-emitting unit and is in a direction different from the first light-receiving axis; a second electronic circuit board on which the second light-receiving unit is arranged; and a smoke detection unit that determines the type of smoke in the air based on a signal generated by the first light-receiving unit when the light-emitting unit emits light and a signal generated by the second light-receiving unit when the light-emitting unit emits light, wherein the first light-receiving axis is inclined with respect to the vertical direction of the first electronic circuit board. [Effects of the Invention]

[0022] The dual-light-receiving smoke detector according to the present invention can be more easily miniaturized than dual-light-receiving smoke detectors according to conventional techniques. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a diagram illustrating a configuration of a smoke detection device according to an embodiment; [Figure 2] FIG. 2 is an external view of a light blocking member according to an embodiment. [Figure 3] FIG. 2 is a cross-sectional view of a light blocking member according to an embodiment. [Figure 4] FIG. 10 is an external view of a light blocking member according to a modified example. [Figure 5] FIG. 10 is an external view of a light blocking member according to a modified example. [Figure 6] FIG. 10 is an external view of a light blocking member according to a modified example. [Figure 7] FIG. 10 is an external view of a light blocking member according to a modified example. [Figure 8] FIG. 10 is a diagram schematically illustrating the configuration of a smoke detection device to be compared with the smoke detection device according to a modified example. [Figure 9] FIG. 10 is a diagram schematically illustrating the configuration of a smoke detection device according to a modified example. [Figure 10] FIG. 10 is a diagram schematically illustrating the configuration of a smoke detection device according to a modified example. [Figure 11] FIG. 1 is a diagram schematically illustrating the configuration of a smoke detection device according to a conventional technique. DETAILED DESCRIPTION OF THE INVENTION

[0024] [Embodiment] A smoke detection device 1 according to one embodiment of the present invention will be described below. The smoke detection device 1 has components in common with a smoke detection device 9 according to the prior art. Therefore, the following will describe the differences between the smoke detection device 1 and the smoke detection device 9, and will omit a description of the common features. Furthermore, in the following description, the components of the smoke detection device 1 that are common to the components of the smoke detection device 9 will be designated by the same reference numerals as those used in the smoke detection device 9.

[0025] FIG. 1 is a diagram showing a schematic configuration of a smoke detection device 1. However, in FIG. 1, components that are not related to the features of the present invention are omitted. FIG. 1(A) is a plan view of the smoke detection device 1 with the lid of the container removed. FIG. 1(B) is a view of the cross section indicated by the dashed line in FIG. 1(A) as viewed in the direction of arrow A. However, FIG. 1(B) shows the cross section of the smoke detection device 1 with the lid of the container attached.

[0026] In the following description, for convenience, the direction in which the paper on which FIG. 1(A) is drawn extends is taken as the horizontal plane.

[0027] The smoke detection device 1 has components that are common to the smoke detection device 9, including an electronic circuit board 91 for the light-emitting unit, an electronic circuit board 93 for the second light-receiving unit (an example of a second electronic circuit board), a light-emitting unit 94, a first light-receiving unit 95, a second light-receiving unit 96, and a processor 97.

[0028] The smoke detection device 1 includes a first light receiving section electronic circuit board 11 (an example of a first electronic circuit board) instead of the first light receiving section electronic circuit board 92 included in the smoke detection device 9. The first light receiving section electronic circuit board 11 is disposed substantially parallel to a horizontal plane. That is, the light emitting axis B of the first light receiving section electronic circuit board 11 and the light emitting section 94 are substantially parallel. In this application, "substantially" means "when unintended errors by the manufacturer are not taken into consideration."

[0029] Moreover, the smoke detection device 1 includes a container 12 instead of the container 98 included in the smoke detection device 9. The container 12 has a shorter vertical length than the container 98. The container 12 can have a shorter vertical length than the container 98 because the first light receiving portion electronic circuit board 11 is not inclined relative to the horizontal plane. Like the container 98, the container 12 has an inlet H1 and an outlet H2.

[0030] The smoke detection device 1 also includes a light-blocking member 13, which the smoke detection device 9 does not include. The light-blocking member 13 is a light-blocking member arranged to surround the first light-receiving unit 95. The light-blocking member 13 blocks light directed toward the first light-receiving unit 95 in a direction intersecting the first light-receiving axis C. The light blocked by the light-blocking member 13 includes light emitted from the light-emitting unit 94 and directed toward the first light-receiving unit 95 away from the light-emitting axis B, and light emitted from the light-emitting unit 94 and reflected within the container 12 toward the first light-receiving unit 95. The light-blocking member 13 serves to reduce the effect of these lights on determining the presence or absence of smoke and the type of smoke. The light-blocking member 13 also serves as an attachment member for positioning the first light-receiving unit 95 at a predetermined angle relative to the first light-receiving unit electronic circuit board 11.

[0031] Fig. 2 is an external view of the light-shielding member 13. Fig. 2(A) is a view of the light-shielding member 13 seen from above, Fig. 2(B) is a view of the light-shielding member 13 seen from the right side to the left side of Fig. 1(B), and Fig. 2(C) is a view of the light-shielding member 13 seen from the left side to the right side of Fig. 1(B). Fig. 3 is a cross-sectional view of the light-shielding member 13.

[0032] The light-shielding member 13 includes a light-shielding box 131, which is a component visible from the outside, an aperture plate 132 arranged inside the light-shielding box 131, and a light-receiving unit arrangement plate 133 arranged inside the light-shielding box 131. The light-shielding box 131 is a rectangular tube cut at an angle, with the top surface closed and an opening H3 provided on the top surface. The opening H3 is located on the first light-receiving axis C.

[0033] 2 as long as the light-shielding box 131 is a hollow light-shielding member that houses the first light-receiving unit 95 and has an opening H3 on the first light-receiving axis C. For example, the light-shielding box 131 may have a structure in which a cylinder is cut obliquely, the top surface is closed, and the opening H3 is provided on the top surface.

[0034] The diaphragm plate 132 is a plate-shaped light-blocking member that is housed in the light-blocking box 131, is substantially perpendicular to the first light-receiving axis C, and has a hole H4 on the first light-receiving axis C. The diaphragm plate 132 blocks light that has entered the light-blocking box 131 through the opening H3 in a direction intersecting the first light-receiving axis C, preventing the light from reaching the first light-receiving unit 95. In FIGS. 1 to 3, there is only one diaphragm plate 132, but the light-blocking member 13 may have multiple diaphragm plates 132 arranged in parallel. Furthermore, if sufficient light blocking is achieved by the light-blocking box 131 alone, the light-blocking member 13 does not need to have the diaphragm plate 132.

[0035] The light receiving unit arrangement plate 133 is a plate-like member housed in the light-shielding box 131, substantially perpendicular to the first light receiving axis C, and disposed on the rear side of the diaphragm plate 132 (the side closer to the first light receiving unit electronic circuit board 11), on which the first light receiving unit 95 is attached. The light receiving unit arrangement plate 133 is provided with holes H5 through which connection terminals (leads) of the first light receiving unit 95 pass. The shape of the holes H5 may be cylindrical, prismatic, or the like. The number of holes H5 may be one or more depending on the number and positions of the connection terminals of the first light receiving unit 95.

[0036] In the smoke detection device 1, the first light receiving unit 95 is arranged on the upper side of the light receiving unit arrangement plate 133, and its connection terminal is connected to the first light receiving unit electronic circuit board 11 located below through a hole H5 in the light receiving unit arrangement plate 133. In other words, the first light receiving unit 95 is arranged on the first light receiving unit electronic circuit board 11 via the light blocking member 13.

[0037] As described above, in the smoke detection device 1, the first light receiving axis C is inclined with respect to the vertical direction (perpendicular direction) of the first light receiving portion electronic circuit board 11. Therefore, the length of the container 12 of the smoke detection device 1 in the vertical direction can be made shorter than that of the container 98 of the smoke detection device 9. As a result, the smoke detection device 1 can be made smaller than the smoke detection device 9 more easily.

[0038] [Variations] The above-described embodiment is a specific example of the present invention, and various modifications are possible within the scope of the technical concept of the present invention. Examples of such modifications are shown below. Note that two or more of the following modifications may be combined as appropriate.

[0039] (Variation 1) If the amount of light directed toward the first light receiving portion 95 in a direction intersecting the first light receiving axis C is small enough to be negligible, the smoke detection device 1 does not need to include the light blocking member 13.

[0040] (Variation 2) The shorter the vertical length of the smoke detection device 1, the closer the light blocking member 13 is to the light-emitting axis B, and the higher the probability that light emitted from the light-emitting unit 94 will be reflected by the light blocking member 13. Some of the light reflected by the light blocking member 13 travels toward the second light-receiving unit 96 and adversely affects the signal generated by the second light-receiving unit 96. As a result, the accuracy of smoke detection by the smoke detection device 1 and the accuracy of determining the type of smoke detected are reduced. Therefore, it is desirable to reduce the probability that light emitted from the light-emitting unit 94 will be reflected by the light blocking member 13.

[0041] In order to shorten the vertical length of the smoke detection device 1 and reduce the probability that the light emitted from the light-emitting unit 94 will be reflected by the light-shielding member 13, the edge portion of the light-shielding box 131 closest to the light-emitting axis B may be chamfered. Note that the chamfered shape of the light-shielding box 131 is not limited to being formed by chamfering processing, and may be formed into a chamfered shape when the light-shielding box 131 is molded, for example. Furthermore, the type of chamfering of the light-shielding box 131 may be either a C-chamfer or an R-chamfer (fillet).

[0042] Fig. 4 is a view of the light blocking member 13 according to this modification, seen from the front side of Fig. 1(B). The portion of the light blocking member 13 indicated by the dashed circle in Fig. 4 has a chamfered shape.

[0043] (Variation 3) In order to shorten the vertical length of the smoke detection device 1 and reduce the probability that the light emitted from the light-emitting unit 94 is reflected by the light-shielding member 13, a recess may be provided in the edge portion closest to the light-emitting axis B of the light-shielding box 131.

[0044] 5A and 5B show a top view (FIG. 5A) of the light-shielding member 13 according to this modification, a view (FIG. 5B) of the light-shielding member 13 according to this modification as viewed from the right side to the left side of FIG. 1B, and a view (FIG. 5C) of the light-shielding member 13 according to this modification as viewed from the left side to the right side of FIG. 1B. As shown in FIG. 5, a recess R1 is provided in the light-shielding box 131 of the light-shielding member 13 according to this modification. Note that the recess R1 may form a hole in the light-shielding box 131.

[0045] (Variation 4) If the temperature rises suddenly in a humid environment, the temperature of the light-shielding member 13 may drop below the temperature of the surrounding air, causing the air in contact with the light-shielding member 13 to be cooled by the light-shielding member 13 and condensation to occur. If water droplets form on the surface of the light-shielding member 13 due to condensation, the probability that the light emitted from the light-emitting unit 94 will be reflected by those water droplets increases. Some of the light reflected by the water droplets travels toward the second light-receiving unit 96 and adversely affects the signal generated by the second light-receiving unit 96. Therefore, it is desirable to reduce the probability that the light emitted from the light-emitting unit 94 will be reflected by water droplets.

[0046] Therefore, the edge of the light-shielding box 131 closest to the light-emitting axis B may be configured not to be substantially parallel to the first light-receiving unit electronic circuit board 11. Fig. 6 shows an example of the light-shielding member 13 according to this modification, viewed from the right to the left in Fig. 1(B) (Fig. 6(A)), and from the left to the right in Fig. 1(B) (Fig. 6(B)). Fig. 7 shows another example of the light-shielding member 13 according to this modification, viewed from the right to the left in Fig. 1(B) (Fig. 7(A)), and from the left to the right in Fig. 1(B) (Fig. 7(B)).

[0047] In the smoke detection device 1 according to this modification, when water droplets adhere to the surface of the light-shielding member 13 due to condensation, the water droplets adhering to the edge line L1 of the light-shielding box 131 that is closest to the light-emitting axis B tend to flow down due to their own weight due to the inclination of the edge line L1. This reduces the probability that the light emitted from the light-emitting unit 94 will be reflected by the water droplets.

[0048] (Variation 5) When the light-shielding box 131 of the light-shielding member 13 enters the light-receiving area of ​​the second light-receiving unit 96, some of the light emitted from the light-emitting unit 94 and reflected by the light-shielding box 131 is received by the second light-receiving unit 96, adversely affecting the signal generated by the second light-receiving unit 96. As a result, the accuracy of smoke detection by the smoke detection device 1 and of determining the type of smoke detected decreases. Therefore, it is desirable to position the light-shielding box 131 outside the light-receiving area of ​​the second light-receiving unit 96.

[0049] Fig. 8 is a diagram schematically illustrating the configuration of a smoke detection device 1 (a smoke detection device to be compared with the smoke detection device according to this modified example) when a portion of the light-shielding box 131 is located within the light-receiving area A1 of the second light-receiving unit 96. On the other hand, Fig. 9 is a diagram schematically illustrating the configuration of a smoke detection device 1 when the light-shielding box 131 is located outside the light-receiving area A2 of the second light-receiving unit 96. The smoke detection device 1 configured as shown in Fig. 9 is more likely to detect smoke and determine the type of smoke detected more accurately than the smoke detection device 1 configured as shown in Fig. 8, and is therefore more desirable.

[0050] In the example of Figure 9, the second light receiving unit 96 is positioned closer to the light emitting unit 94 than in the example of Figure 8. As a result, the intersection P1 between the light emitting axis B and the first light receiving axis C is substantially different from the intersection P2 between the light emitting axis B and the second light receiving axis D. By shifting the intersection P1 and the intersection P2 in this way, the vertical length of the smoke detection device 1 can be kept short, while improving the accuracy of smoke detection and determination of the type of smoke detected.

[0051] In the example of Figure 9, the second light receiving unit 96 is positioned closer to the light emitting unit 94 than in the example of Figure 8, but instead, the first light receiving unit 95 may be positioned further away from the light emitting unit 94 than in the example of Figure 8.

[0052] (Variation 6) The first light receiving unit electronic circuit board 11 may be disposed outside the container 12. Fig. 10 is a diagram schematically illustrating a cross section of a smoke detection device 1 according to this modification. In the smoke detection device 1 according to this modification, holes are provided in the container 12 through which connection terminals of electronic components housed in the container 12 and connected to the first light receiving unit electronic circuit board 11 pass. Of these holes, Fig. 10 illustrates hole H6 through which the connection terminal of the first light receiving unit 95 passes. In this case, the first light receiving unit 95 is disposed on the first light receiving unit electronic circuit board 11 via the light blocking member 13 and the container 12.

[0053] In this modification, electronic components that are not housed in the container 12 can be disposed on the first light receiving unit electronic circuit board 11. Electronic components 14 and 15 shown in FIG. 10 are examples of such electronic components.

[0054] In this modified example, compared to when the electronic circuit board 11 for the first light receiving unit is housed in the container 12, there is greater freedom in the position and size of the electronic components to be placed on the electronic circuit board 11 for the first light receiving unit, and electronic components that are not housed in the container 12 can be easily attached to the electronic circuit board 11 for the first light receiving unit.

[0055] (Variation 7) In addition to or instead of the shading member 13, the smoke detection device 1 may be provided with a shading member that is arranged to surround the second light receiving unit 96 and blocks light that travels toward the second light receiving unit 96 in a direction that intersects with the second light receiving axis D.

[0056] (Variation 8) In the above-described embodiment, the light emitter 94 emits polarized light. However, the light emitter 94 may emit unpolarized light. For example, if the light receiving conditions of the first light receiving unit 95 and the second light receiving unit 96 are different, such as when the angle between the light-emitting axis B and the first light-receiving axis C is different from the angle between the light-emitting axis B and the second light-receiving axis D, when the intersection point P1 between the light-emitting axis B and the first light-receiving axis C is different from the intersection point P2 between the light-emitting axis B and the second light-receiving axis D, or when only one of the first light receiving unit 95 and the second light receiving unit 96 is surrounded by a light-shielding member, the ratio between the light intensity indicated by the signal generated by the first light receiving unit 95 and the light intensity indicated by the signal generated by the second light receiving unit 96 may vary depending on the type of smoke. Therefore, the light emitted by the light emitter 94 does not necessarily have to be polarized. [Explanation of symbols]

[0057] 1...smoke detection device, 9...smoke detection device, 11...electronic circuit board for first light receiving unit, 12...container, 13...light-shielding member, 14...electronic component, 15...electronic component, 91...electronic circuit board for light emitting unit, 92...electronic circuit board for first light receiving unit, 93...electronic circuit board for second light receiving unit, 94...light emitting unit, 95...first light receiving unit, 96...second light receiving unit, 97...processor, 98...container, 131...light-shielding box, 132...aperture plate, 133...light receiving unit placement plate.

Claims

1. a light-emitting unit that emits light; a first light receiving unit having a first light receiving axis that intersects with a light emitting axis of the light emitting unit; a first electronic circuit board on which the first light receiving unit is arranged; a second light receiving unit having a second light receiving axis that intersects with the light emitting axis of the light emitting unit and is in a direction different from the first light receiving axis; a second electronic circuit board on which the second light receiving unit is disposed; a smoke determination unit that determines the type of smoke in the air based on a signal generated by the first light receiving unit when the light emitting unit emits light and a signal generated by the second light receiving unit when the light emitting unit emits light; Equipped with The first light-receiving axis is inclined with respect to the vertical direction of the first electronic circuit board. Smoke detection device.

2. a light-shielding box that is a hollow light-shielding member that houses the first light-receiving unit and has an opening on the first light-receiving axis; 10. The smoke detection device of claim 1.

3. The edge portion of the light-shielding box closest to the light-emitting axis of the light-emitting unit has at least one of a chamfered shape, a shape having a recess, and a shape that is not substantially parallel to the first electronic circuit board.

3. The smoke detection device of claim 2.

4. a diaphragm plate, which is a plate-shaped light-blocking member that is housed in the light-blocking box and is substantially perpendicular to the first light-receiving axis and has a hole on the first light-receiving axis; 3. The smoke detection device of claim 2.

5. The light-shielding box is disposed outside the light-receiving area of ​​the second light-receiving unit.

3. The smoke detection device of claim 2.

6. The intersection of the light-emitting axis of the light-emitting unit and the first light-receiving axis is substantially different from the intersection of the light-emitting axis of the light-emitting unit and the second light-receiving axis.

10. The smoke detection device of claim 1.

7. a container that houses the light-emitting unit, the first light-receiving unit, and the second light-receiving unit and has an inlet for air flowing in from the outside and an outlet for air flowing out to the outside, The first electronic circuit board is disposed outside the container.

10. The smoke detection device of claim 1.

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