Smoke detection device

Abstract

The invention provides a two-light-receiving type smoke detection device which is more compact than the prior art. A two-light-receiving smoke detection device (1) according to one embodiment of the present invention is provided with: a light emitting unit (94) that emits polarized light; a first light-receiving unit (95) having a first light-receiving axis (C) intersecting the light-emitting axis (B) of the light-emitting unit (94); a second light-receiving unit (96) having a second light-receiving axis (D) that intersects the light-emitting axis (B) and is different from the first light-receiving axis (C); a processor (97) that determines the type of smoke in the 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 light-shielding member (13) that accommodates the first light-receiving unit (95) and shields light toward the first light-receiving unit (95) in a direction intersecting the first light-receiving axis (C). The first light receiving axis (C) is inclined with respect to the vertical direction of the electronic circuit substrate (11) for the first light receiving unit. The light-shielding member (13) also functions as a mounting member capable of mounting the first light-receiving unit (95) in an inclined state on the electronic circuit board (11) for the first light-receiving unit.

Description

Technical Field

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

[0002] There is a smoke detection device that detects the generation of smoke in the space of the monitored object by detecting the smoke contained in the space of the monitored object. As one type of smoke detection device, there is a so-called photoelectric type. The photoelectric smoke detection device detects smoke based on a signal generated when the light receiving unit receives reflected light, which is light emitted from the light emitting unit and reflected by smoke particles in the air flowing from the outside into the container that accommodates the light emitting unit and the light receiving unit.

[0003] Another method of a photoelectric smoke detector is a dual-light-receiving method. As one method of a dual-light-receiving smoke detector, there is a method in which polarized light is emitted from a light-emitting unit in the direction of a light-emitting axis, and the type of smoke in the air is determined based on signals generated by two light-receiving units having light-receiving axes intersecting the light-emitting axis from different directions.

[0004] As a patent document that discloses a dual-light-receiving type smoke detection device, there is Patent Document 1, for example.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-181507 Summary of the invention

[0008] Problems to be solved by the invention

[0009] Fig.11 FIG. 2 is a diagram schematically showing the structure of a conventional two-light-receiving type smoke detection device 9. Fig.11 In the drawings, the structural parts irrelevant to the features of the present invention are omitted from illustration. Fig.11 (A) is a plan view of a state where the cover of the container of the smoke detection device 9 is removed. Fig.11 (B) is viewed from the direction of arrow A Fig.11 FIG. 9 is a cross-sectional view of the smoke detection device 9 shown by the dotted line in (A). Fig.11 (B) shows a cross section of the smoke detection device 9 in a state where the lid of the container is attached.

[0010] In the following description, for convenience, Fig.11 The direction in which the paper surface of (A) extends is set to be a horizontal plane.

[0011] The smoke detection device 9 includes a light emitting electronic circuit board 91 , a first light receiving electronic circuit board 92 , a second light receiving electronic circuit board 93 , a light emitting unit 94 , a first light receiving unit 95 , a second light receiving unit 96 , a processor 97 , and a container 98 .

[0012] The light emitting unit electronic circuit board 91 is an electronic circuit board arranged to stand vertically with respect to a horizontal plane. A light emitting unit 94 is arranged on the light emitting unit electronic circuit board 91 .

[0013] The first light receiving unit electronic circuit board 92 is an electronic circuit board arranged on a plane inclined with respect to a horizontal plane. A first light receiving unit 95 and a processor 97 are arranged on the first light receiving unit electronic circuit board 92 .

[0014] The second light receiving unit electronic circuit board 93 is an electronic circuit board arranged to stand vertically with respect to a horizontal plane. A second light receiving unit 96 is arranged on the second light receiving unit electronic circuit board 93 .

[0015] In addition, the processor 97 may be disposed on an electronic circuit substrate other than the first light-receiving unit electronic circuit substrate 92 (for example, the light-emitting unit electronic circuit substrate 91 or the second light-receiving unit electronic circuit substrate 93 ).

[0016] The light emitting unit 94 Fig.11 Polarized light is emitted in the direction of the light emission axis (hereinafter referred to as "light emission axis B") indicated by the middle arrow B. For example, when the polarized light emitted by the light emitting unit 94 is linearly polarized light, the direction of the straight line is perpendicular to the horizontal plane, and when 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.

[0017] The first light receiving unit 95 receives light from the Fig.11 The first light receiving axis C intersects the light emitting axis B at a predetermined angle in a vertical plane (a plane perpendicular to the horizontal plane) including the light emitting axis B. The electronic circuit board 92 for the first light receiving unit is arranged at a position perpendicular to the first light receiving axis C.

[0018] The second light receiving unit 96 receives the light from the Fig.11 The light in the direction of the second light receiving axis (hereinafter referred to as "the second light receiving axis D") indicated by the arrow D in (A) is used to generate 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 the light emitting axis B at a predetermined angle in a horizontal plane containing the light emitting axis B.

[0019] In addition, 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.

[0020] The processor 97 is a computing device for processing data, and functions 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 flowing into the container 98 from the outside of the container 98 based on the comparison result of 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 and a predetermined threshold value.

[0021] The container 98 accommodates 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.

[0022] In the above-mentioned conventional smoke detection device 9, the first light receiving unit electronic circuit substrate 92 is arranged in a manner inclined relative to the horizontal plane, and the second light receiving unit electronic circuit substrate 93 is arranged in a manner upright relative to the horizontal plane, so that the vertical direction ( Fig.11 The length (in the longitudinal direction) of (B) becomes longer, and the size of the smoke detection device 9 becomes larger.

[0023] In view of the above situation, the present invention provides a dual-light-receiving type smoke detection device that is easier to be miniaturized than the prior art.

[0024] Means for solving problems

[0025] In order to solve the above-mentioned problems, the present invention provides a smoke detection device, which comprises: a light-emitting part, which emits light; a first light-receiving part, which has a first light-receiving axis intersecting with the light-emitting axis of the light-emitting part; a first electronic circuit substrate, on which the first light-receiving part is configured; a second light-receiving part, which has a second light-receiving axis intersecting with the light-emitting axis of the light-emitting part and in a different direction from the first light-receiving axis; a second electronic circuit substrate, on which the second light-receiving part is configured; and a smoke determination part, which determines the type of smoke in the air based on a signal generated by the first light-receiving part when the light-emitting part emits light and a signal generated by the second light-receiving part when the light-emitting part emits light, wherein the first light-receiving axis is inclined relative to the vertical direction of the first electronic circuit substrate.

[0026] Effects of the Invention

[0027] The dual-light-receiving type smoke detection device of the present invention can be easily miniaturized compared to the dual-light-receiving type smoke detection device of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a diagram schematically showing the structure of a smoke detection device according to one embodiment.

[0029] Figure 2 This is an appearance diagram of a light shielding member according to one embodiment.

[0030] Figure 3 is a cross-sectional view of a light shielding member according to one embodiment.

[0031] Figure 4 This is an appearance diagram of a light shielding component according to a modified example.

[0032] Figure 5 This is an appearance diagram of a light shielding component according to a modified example.

[0033] Figure 6 This is an appearance diagram of a light shielding component according to a modified example.

[0034] Figure 7 This is an appearance diagram of a light shielding component according to a modified example.

[0035] Figure 8 FIG. 1 is a diagram schematically showing a structure of a smoke detection device for comparison with a smoke detection device according to a modified example.

[0036] Fig. 9 FIG. 1 is a diagram schematically showing a structure of a smoke detection device according to a modified example.

[0037] Fig.10 FIG. 1 is a diagram schematically showing a structure of a smoke detection device according to a modified example.

[0038] Fig.11 FIG. 1 is a diagram schematically showing the structure of a conventional smoke detection device. DETAILED DESCRIPTION

[0039] [Implementation Method]

[0040] The smoke detection device 1 according to one embodiment of the present invention is described below. The smoke detection device 1 has a common structure with the smoke detection device 9 of the prior art. Therefore, the differences between the smoke detection device 1 and the smoke detection device 9 are described below, and the description of the common points is omitted. In addition, in the following description, the same reference numerals as those used in the smoke detection device 9 are used for the common structure of the smoke detection device 1 and the structure of the smoke detection device 9.

[0041] Figure 1 Schematically shows the structure of the smoke detection device 1. Figure 1 In the drawings, components not related to the features of the present invention are omitted from the drawings. Figure 1(A) is a plan view of the smoke detection device 1 in a state where the cover of the container is removed. Figure 1 (B) is viewed from the direction of arrow A Figure 1 The cross section shown by the dashed line in (A). Figure 1 (B) shows a cross section of the smoke detection device 1 in a state where the lid of the container is attached.

[0042] In the following description, for convenience, Figure 1 The direction in which the paper surface of (A) extends is set to be a horizontal plane.

[0043] The smoke detection device 1 has an electronic circuit substrate 91 for a light emitting unit, an electronic circuit substrate 93 for a second light receiving unit (an example of a second electronic circuit substrate), a light emitting unit 94, a first light receiving unit 95, a second light receiving unit 96, and a processor 97 as components common to the smoke detection device 9.

[0044] The smoke detection device 1 has an electronic circuit substrate 11 for a first light receiving unit (an example of a first electronic circuit substrate) instead of the electronic circuit substrate 92 for a first light receiving unit of the smoke detection device 9. The electronic circuit substrate 11 for the first light receiving unit is arranged substantially parallel to the horizontal plane. That is, the electronic circuit substrate 11 for the first light receiving unit is substantially parallel to the light emitting axis B of the light emitting unit 94. In addition, in the present application, "substantially" means "without considering the unintentional error of the manufacturer".

[0045] In addition, the smoke detection device 1 includes a container 12 instead of the container 98 included in the smoke detection device 9. The container 12 is shorter in the vertical direction than the container 98. The reason why the container 12 can be shorter in the vertical direction than the container 98 is that the first light receiving unit electronic circuit substrate 11 is not inclined relative to the horizontal plane. In addition, the container 12 has an inlet H1 and an outlet H2 similarly to the container 98.

[0046] In addition, the smoke detection device 1 includes a light shielding member 13 that the smoke detection device 9 does not have. The light shielding member 13 is a light shielding member configured in a manner to surround the first light receiving portion 95. The light shielding member 13 blocks light directed toward the first light receiving portion 95 in a direction intersecting the first light receiving axis C. The light blocked by the light shielding member 13 includes light emitted from the light emitting portion 94 and deviated from the light emitting axis B and directed toward the first light receiving portion 95, and light emitted from the light emitting portion 94 and reflected in the container 12 and directed toward the first light receiving portion 95. The light shielding member 13 serves to reduce the influence of these lights on the determination of the presence or absence of smoke and the determination of the type of smoke. In addition, the light shielding member 13 also serves as a mounting member for configuring the first light receiving portion 95 at a predetermined angle relative to the electronic circuit substrate 11 for the first light receiving portion.

[0047] Figure 2It is an appearance diagram of the light shielding member 13 . Figure 2 (A) is a view of the light shielding member 13 viewed from above, Figure 2 (B) is from Figure 1 The light shielding member 13 is viewed from the right side of (B) to the left. Figure 2 (C) is from Figure 1 The left side of (B) is a diagram of the light shielding member 13 viewed to the right. Figure 3 It is a cross-sectional view of the light shielding member 13 .

[0048] The light shielding component 13 includes: a light shielding box 131, which is a structure visible from the outside; an aperture plate 132, which is arranged on the inner side of the light shielding box 131; and a light receiving unit configuration plate 133, which is arranged on the inner side of the light shielding box 131. The light shielding box 131 is configured by cutting a square tube obliquely, blocking the upper surface, and providing an opening H3 on the upper surface. The opening H3 is located on the first light receiving axis C.

[0049] In addition, the light shielding box 131 can be any hollow light shielding member that accommodates the first light receiving unit 95 and has an opening H3 on the first light receiving axis C. The shape of the light shielding box 131 is not limited to Figure 2 For example, the light shielding box 131 may be a structure in which a cylinder is cut obliquely, the upper surface is blocked, and the opening H3 is provided on the upper surface.

[0050] The aperture plate 132 is a plate-shaped light shielding member housed in the light shielding box 131, substantially perpendicular to the first light receiving axis C, and having a hole H4 on the first light receiving axis C. The aperture plate 132 shields light that enters the light shielding box 131 through the opening H3 in a direction intersecting the first light receiving axis C so that the light does not reach the first light receiving unit 95. Figure 1 to Figure 3 In the embodiment, the number of the aperture plate 132 is one, but the light shielding member 13 may include a plurality of aperture plates 132 arranged in parallel. In addition, when sufficient light shielding is performed only by the light shielding box 131, the light shielding member 13 may not include the aperture plate 132.

[0051] The light receiving unit configuration plate 133 is housed in the light shielding box 131, is substantially perpendicular to the first light receiving axis C, is arranged at a position further back than the aperture plate 132 (close to the side of the electronic circuit substrate 11 for the first light receiving unit), and is used to mount the plate-shaped component of the first light receiving unit 95 thereon. The light receiving unit configuration plate 133 is provided with a hole H5 for the connection terminal (lead) of the first light receiving unit 95 to pass through. In addition, the shape of the hole H5 can be any shape such as a cylindrical shape and a prism shape. In addition, depending on the number and position of the connection terminals of the first light receiving unit 95, the number of holes H5 can be one or more than two.

[0052] In the smoke detection device 1, the first light receiving unit 95 is arranged on the upper side of the light receiving unit configuration plate 133, and its connection terminal is connected to the first light receiving unit electronic circuit substrate 11 located on the lower side through the hole H5 of the light receiving unit configuration plate 133. That is, the first light receiving unit 95 is arranged on the first light receiving unit electronic circuit substrate 11 via the light shielding member 13.

[0053] As described above, in the smoke detection device 1, the first light receiving axis C is inclined relative to the vertical direction (vertical direction) of the first light receiving unit electronic circuit board 11. Therefore, the length of the container 12 of the smoke detection device 1 can be shortened in the vertical direction compared to the container 98 of the smoke detection device 9. As a result, the smoke detection device 1 can be easily miniaturized compared to the smoke detection device 9.

[0054] [Modifications]

[0055] The above-mentioned embodiment is a specific example of the present invention, and various modifications can be made within the scope of the technical concept of the present invention. The following shows their modified examples. In addition, two or more modified examples shown below can also be appropriately combined.

[0056] (Variant 1)

[0057] When the amount of light directed toward the first light receiving unit 95 in the direction intersecting the first light receiving axis C is negligibly small, the smoke detection device 1 may not include the light shielding member 13 .

[0058] (Variant 2)

[0059] The shorter the vertical length of the smoke detection device 1 is, the closer the light shielding member 13 is to the light-emitting axis B, and the higher the probability that the light emitted from the light-emitting unit 94 is reflected by the light shielding member 13. A portion of the light reflected by the light shielding member 13 is directed toward the second light receiving unit 96, which adversely affects the signal generated by the second light receiving unit 96. As a result, the accuracy of smoke detection and determination of the type of detected smoke by the smoke detection device 1 is reduced. Therefore, the lower the probability that the light emitted from the light-emitting unit 94 is reflected by the light shielding member 13, the better.

[0060] 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 portion 94 is 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. In addition, the chamfered shape of the light shielding box 131 is not limited to being formed by chamfering, and for example, it may be formed into a chamfered shape when the light shielding box 131 is formed. In addition, the type of chamfer of the light shielding box 131 may be any one of C chamfering and R chamfering (rounded corners).

[0061] Figure 4 is from Figure 1FIG. 13 is a diagram of the light shielding member 13 of the modified example viewed from the front direction of FIG. Figure 4 The portion indicated by the dotted circle in the figure is chamfered.

[0062] (Variant 3)

[0063] 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 at the edge of the light shielding box 131 closest to the light emission axis B.

[0064] Figure 5 This is a diagram of the light shielding member 13 of the modified example as viewed from above ( Figure 5 (A)), from Figure 1 The figure (B) viewed from the right side to the left Figure 5 (B)) and from Figure 1 The figure (B) viewed from the left side to the right Figure 5 (C)). Figure 5 As shown in FIG. 1 , a recess R1 is provided in the light shielding box 131 of the light shielding member 13 of this modification. Alternatively, a hole may be formed in the light shielding box 131 by utilizing the recess R1.

[0065] (Variant 4)

[0066] When the temperature rises sharply under high humidity, the temperature of the light shielding member 13 becomes lower than the temperature of the surrounding air, and the air in contact with the light shielding member 13 is sometimes cooled by the light shielding member 13 to generate condensation. If water droplets adhere to the surface of the light shielding member 13 due to condensation, the probability that the light emitted from the light emitting unit 94 is reflected by these water droplets becomes high. A part of the light reflected by the water droplets goes toward the second light receiving unit 96, which has an adverse effect on the signal generated by the second light receiving unit 96. Therefore, the lower the probability that the light emitted from the light emitting unit 94 is reflected by water droplets, the better.

[0067] Therefore, the edge of the light shielding box 131 closest to the light emission axis B may be configured to be substantially non-parallel to the first light receiving unit electronic circuit board 11 . Figure 6 This is an example of the light shielding member 13 of this modification. Figure 1 The figure (B) viewed from the right side to the left Figure 6 (A)) and from Figure 1 The left side of (B) is viewed from the right side ( Figure 6 (B)). In addition, Figure 7 Another example of the light shielding member 13 of this modified example is Figure 1 The figure (B) viewed from the right side to the left Figure 7 (A)) and from Figure 1 The left side of (B) is viewed from the right side ( Figure 7 (B)).

[0068] In the smoke detection device 1 of this modified example, when water droplets are attached to the surface of the light shielding member 13 due to condensation, the water droplets attached to the ridge line L1 of the light shielding box 131 closest to the light emission axis B in the light shielding box 131 are easily flowed down by their own weight due to the inclination of the ridge line L1. Therefore, the probability that the light emitted from the light emitting unit 94 is reflected by the water droplets is reduced.

[0069] (Variant 5)

[0070] When the light shielding box 131 of the light shielding member 13 enters the light receiving area of ​​the second light receiving unit 96, a part 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, thereby causing an adverse effect on the signal generated by the second light receiving unit 96. As a result, the accuracy of smoke detection and determination of the type of detected smoke by the smoke detection device 1 is reduced. Therefore, it is preferred that the light shielding box 131 is arranged outside the light receiving area of ​​the second light receiving unit 96.

[0071] Figure 8 1 is a diagram schematically showing the structure of the smoke detection device 1 (the smoke detection device to be compared with the smoke detection device of the modified example) when a part of the light shielding box 131 is arranged in the light receiving area A1 of the second light receiving unit 96. Fig. 9 This is a diagram schematically showing the configuration of the smoke detection device 1 when the light shielding box 131 is arranged outside the light receiving area A2 of the second light receiving unit 96 . Fig. 9 The smoke detection device 1 of the structure Figure 8 Compared with the smoke detection device 1 having a structure of , the probability of high accuracy in smoke detection and determination of the type of detected smoke is high, and is therefore preferred.

[0072] exist Fig. 9 In the example, Figure 8 Compared with the example of FIG. 1 , the second light receiving unit 96 is arranged at a position close to the light emitting unit 94. As a result, the intersection point P1 between the light emitting axis B and the first light receiving axis C is substantially different from the intersection point P2 between the light emitting axis B and the second light receiving axis D. In this way, by staggering the intersection point P1 and the intersection point P2, the vertical length of the smoke detection device 1 can be maintained short, and the accuracy of smoke detection and determination of the type of detected smoke can be improved.

[0073] In addition, Fig. 9 In the example, Figure 8 Compared with the example of FIG. 1 , the second light receiving unit 96 is arranged at a position close to the light emitting unit 94, but it can also be replaced with Figure 8 Compared with the example, the first light receiving unit 95 is arranged at a position away from the light emitting unit 94.

[0074] (Variant 6)

[0075] The first light-receiving electronic circuit board 11 may be disposed outside the container 12 . Fig.10 1 is a diagram schematically showing a cross section of the smoke detection device 1 of this modification. In the smoke detection device 1 of this modification, a hole is provided in the container 12 for passing the connection terminal of the electronic component, and the electronic component is housed in the container 12 and connected to the electronic circuit board 11 for the first light receiving unit. Fig.10 , among these holes, a hole H6 through which the connection terminal of the first light receiving unit 95 passes is shown. In this case, the first light receiving unit 95 is disposed on the first light receiving unit electronic circuit board 11 via the light shielding member 13 and the container 12.

[0076] In this modification, electronic components that are not housed in the container 12 can be arranged on the first light-receiving unit electronic circuit board 11 . Fig.10 The electronic components 14 and 15 shown are examples of these electronic components.

[0077] In this variation, compared with the case where the electronic circuit substrate 11 for the first light receiving portion is housed in the container 12, the freedom of the position and size of the electronic components arranged on the electronic circuit substrate 11 for the first light receiving portion is improved, and the electronic components not housed in the container 12 can be easily installed on the electronic circuit substrate 11 for the first light receiving portion.

[0078] (Variant 7)

[0079] The smoke detection device 1 may include a light shielding member arranged to surround the second light receiving section 96 and shielding light toward the second light receiving section 96 in a direction intersecting the second light receiving axis D in addition to the light shielding member 13 or in place of the light shielding member 13 .

[0080] (Variant 8)

[0081] In the above-mentioned embodiment, the light emitting unit 94 emits polarized light, but the light emitting unit 94 may also emit non-polarized light. For example, if the light receiving conditions of the first light receiving unit 95 and the light receiving conditions of 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 and the angle between the light emitting axis B and the second light receiving axis D are different, when the intersection point P1 of the light emitting axis B and the first light receiving axis C and the intersection point P2 of the light emitting axis B and the second light receiving axis D are different, 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 of the intensity of light represented by the signal generated by the first light receiving unit 95 and the intensity of light represented by the signal generated by the second light receiving unit 96 may change depending on the type of smoke. Therefore, the light emitted by the light emitting unit 94 may not necessarily be polarized light.

[0082] Description of symbols

[0083] 1: smoke detection device; 9: smoke detection device; 11: electronic circuit substrate for the first light receiving part; 12: container; 13: light shielding component; 14: electronic component; 15: electronic component; 91: electronic circuit substrate for the light emitting part; 92: electronic circuit substrate for the first light receiving part; 93: electronic circuit substrate for the second light receiving part; 94: light emitting part; 95: first light receiving part; 96: second light receiving part; 97: processor; 98: container; 131: light shielding box; 132: aperture plate; 133: light receiving part configuration plate.

Claims

1. A smoke detection device, comprising: a light emitting portion that emits light; A first light receiving portion having a first light receiving axis intersecting with the light emitting axis of the light emitting portion; A first electronic circuit substrate, which is provided with the first light receiving portion; A second light receiving portion having a second light receiving axis intersecting with the light emitting axis of the light emitting portion and in a different direction from the first light receiving axis; A second electronic circuit substrate, which is provided with the second light receiving portion; as well as 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, The first light receiving axis is inclined relative to a vertical direction of the first electronic circuit substrate.

2. The smoke detection device according to claim 1, wherein: The smoke detection device includes a light shielding box for accommodating the first light receiving unit. The light shielding box is a hollow light shielding member having an opening on the first light receiving axis.

3. The smoke detection device according to claim 2, wherein: An edge portion of the light shielding box closest to the light emission axis of the light emitting unit is 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 substrate.

4. The smoke detection device according to claim 2, wherein: The smoke detection device includes an aperture plate housed in the light shielding box. The aperture plate is substantially perpendicular to the first light receiving axis and is a plate-shaped light shielding member having a hole on the first light receiving axis.

5. The smoke detection device according to claim 2, wherein: The light shielding box is arranged outside the light receiving area of ​​the second light receiving unit.

6. The smoke detection device according to claim 1, wherein: An intersection point of the light emitting axis of the light emitting portion and the first light receiving axis is substantially different from an intersection point of the light emitting axis of the light emitting portion and the second light receiving axis.

7. The smoke detection device according to claim 1, wherein: The smoke detection device includes a container, the container accommodating the light emitting unit, the first light receiving unit, and the second light receiving unit, the container having an inlet for air flowing in from the outside and an outlet for air flowing out to the outside, The first electronic circuit substrate is disposed outside the container.

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