Smoke sensor

Abstract

To provide a smoke detector for achieving miniaturization.SOLUTION: A smoke detector includes: a housing attached to an attached surface and internally having a smoke detection space to detect smoke; a light emitting part for irradiating the smoke detection space with light; a light receiving part for receiving the light radiated from the light emitting part and scattered in the smoke detection space; and a substrate arranged inside the housing and mounting the light emitting part and the light receiving part. In the smoke detector, the housing has a main body where a wall part to form the smoke detection space is formed. Recessed notched parts are formed on the substrate. The substrate is arranged partially in the periphery of the wall part. The wall part is arranged on an inner side of the notched parts.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a smoke detector that senses smoke generated by a fire or the like.

Background Art

[0002] Conventionally, as a smoke detector that senses smoke generated by a fire or the like, when smoke enters a smoke detection space, the light irradiated from a light emitting part is scattered by the smoke and reaches a light receiving part, and thus a photoelectric smoke detector that senses the smoke is known. Patent Document 1 discloses a smoke detector that is attached to an attachment surface such as a ceiling and in which a light emitting part and a light receiving part are chip components surface-mounted on a substrate. In Patent Document 1, the substrate is provided in a direction perpendicular to the attachment surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the substrate of the smoke detector disclosed in Patent Document 1 is attached in a direction perpendicular to the attachment surface, the overall height of the smoke detector becomes high. Therefore, miniaturization of the smoke detector is desired.

[0005] The present invention solves the above problems and provides a smoke detector capable of achieving miniaturization.

Means for Solving the Problems

[0006] The smoke detector according to the present invention comprises a housing that is attached to a mounting surface and has a smoke detection space formed inside for detecting smoke, a light-emitting unit that irradiates light into the smoke detection space, a light-receiving unit that receives light irradiated from the light-emitting unit and scattered in the smoke detection space, and a substrate provided inside the housing on which the light-emitting unit and the light-receiving unit are mounted, It has a base that is attached to the mounting surface, The enclosure includes a main body with walls that form the smoke detection space. The main body is attached to the base, and the wall portion that forms the smoke detection space is not provided on the circuit board, but is provided at approximately the same height as the circuit board, and is provided so as to be sandwiched between the light-emitting portion and the light-receiving portion mounted on the circuit board. ru. Furthermore, the smoke detector according to the present invention comprises a housing that is attached to a mounting surface and has a smoke detection space formed inside for detecting smoke, a light-emitting unit that irradiates light into the smoke detection space, a light-receiving unit that receives light irradiated from the light-emitting unit and scattered in the smoke detection space, and a substrate provided inside the housing on which the light-emitting unit and the light-receiving unit are mounted, wherein the smoke detector comprises a base that is attached to the mounting surface, the housing comprises a main body on which a wall portion forming the smoke detection space is formed, the main body is attached to the base, the wall portion forming the smoke detection space is provided at approximately the same height as the substrate, the light-emitting unit and the light-receiving unit mounted on the substrate are provided on the outer periphery of the wall portion, the wall portion comprises a wall portion having a first hole through which light irradiated from the light-emitting unit passes, and a wall portion having a second hole through which light received by the light-receiving unit passes. Furthermore, the smoke detector according to the present invention comprises a housing that is attached to a mounting surface and has a smoke detection space formed inside for detecting smoke, a light-emitting unit that irradiates light into the smoke detection space, a light-receiving unit that receives light irradiated from the light-emitting unit and scattered in the smoke detection space, and a substrate provided inside the housing on which the light-emitting unit and the light-receiving unit are mounted, wherein the housing has a main body on which a wall portion forming the smoke detection space is formed, the wall portion forming the smoke detection space is provided at approximately the same height as the substrate, the light-emitting unit and the light-receiving unit mounted on the substrate are provided on the outer periphery side of the wall portion, a concave notch is formed in the substrate, the notch is formed in a substantially trapezoidal shape with the outer side being longer and corresponding to the shape of the wall portion. [Effects of the Invention]

[0007] This invention One embodiment According to the specifications, the circuit board is mounted horizontally to the mounting surface. This allows the height of the smoke detector to be kept low, thus enabling a smaller smoke detector. Also According to one embodiment of the present invention, If the optical axis of the chip component is perpendicular to the substrate, the smoke detection space becomes larger in the height direction. However, in this invention, since the optical axis of the chip component is parallel to the substrate, there is no need to increase the height of the smoke detection space, and the smoke detector can be miniaturized. [Brief explanation of the drawing]

[0008] [Figure 1] This is an assembled perspective view showing a smoke detector 100 according to Embodiment 1 of the present invention. [Figure 2] This is a top view showing a smoke detector 100 according to Embodiment 1 of the present invention. [Figure 3] This is a side view showing a smoke detector 100 according to Embodiment 1 of the present invention. [Figure 4] This is an exploded perspective view showing a smoke detector 100 according to Embodiment 1 of the present invention. [Figure 5] This is a perspective cross-sectional view showing a smoke detector 100 according to Embodiment 1 of the present invention. [Figure 6] This is a top cross-sectional view showing a smoke detector 100 according to Embodiment 1 of the present invention. [Figure 7]This is a side cross-sectional view showing the smoke detector 100 according to Embodiment 1 of the present invention, and is a diagram showing the light-emitting part 6A. [Figure 8] This is a side cross-sectional view showing a smoke detector 100 according to Embodiment 1 of the present invention, and a diagram showing the light receiving unit 6B. [Figure 9] This is a top cross-sectional view showing a smoke detector 100 according to Embodiment 1 of the present invention, and is an enlarged view of Figure 6. [Figure 10] This is a top view showing the circuit board 6 of the smoke detector 100 according to Embodiment 1 of the present invention. [Figure 11] This is a schematic cross-sectional view showing the positional relationship between the substrate 6, the smoke detection space 33, and the optical stand 4A in the smoke detector 100 according to Embodiment 1 of the present invention. [Modes for carrying out the invention]

[0009] Embodiment 1. Hereinafter, embodiments of the smoke detector according to the present invention will be described with reference to the drawings. Figure 1 is an assembled perspective view showing the smoke detector according to Embodiment 1 of the present invention, Figure 2 is a top view showing the smoke detector according to Embodiment 1 of the present invention, and Figure 3 is a side view showing the smoke detector according to Embodiment 1 of the present invention. Figure 4 is an exploded perspective view showing the smoke detector according to Embodiment 1 of the present invention, Figure 5 is a perspective cross-sectional view showing the smoke detector according to Embodiment 1 of the present invention, and Figure 6 is a top cross-sectional view showing the smoke detector according to Embodiment 1 of the present invention. Figure 6 is a cross-sectional view of AA in Figure 3.

[0010] As shown in FIGS. 1 to 6, the smoke detector 100 is installed on an attachment surface such as a ceiling in a monitoring space such as the interior of a house. The smoke detector 100 includes a housing 10 including a bottomed cylindrical first cover 11 and a base portion 12 provided on the back side of the first cover 11. The smoke detector 100 includes a main body 3 housed in the housing 10 and partitioning the space inside the housing 10 vertically, a lid portion 4 provided on the main body 3, an optical bench cover 5 provided on the lid portion 4, and a labyrinth wall housed in the optical bench cover 5 and having a light shielding function. Further, a smoke detection space 33 for detecting smoke is formed inside the housing 10, which will be described in detail later.

[0011] Furthermore, the smoke detector 100 includes a substrate 6 provided between the main body 3 and the lid portion 4, a battery for supplying operating power to various circuits provided on the substrate 6, and a speaker 8 for outputting sound or the like. On the substrate 6, a light emitting portion 6A for irradiating light to the smoke detection space 33 for detecting smoke and a light receiving portion 6B for receiving the light irradiated from the light emitting portion 6A and scattered in the smoke detection space 33 are surface-mounted.

[0012] An opening 1 extending in the circumferential direction is formed in the first cover 11 of the housing 10. The openings 1 are formed in two rows in the vertical direction. The opening 1 communicates with the smoke passage inside the housing 10. The first cover 11 includes a flat lower surface portion 11A in which an opening 11A1 for a push button is formed, a cylindrical side surface portion 11B, and an annular corner portion 11C connecting the lower surface portion 11A and the side surface portion 11B. The lower surface portion 11A faces the main body 3.

[0013] The base portion 12 of the housing 10 is provided on the upper part of the first cover 11. By fixing this base portion 12 to the ceiling surface or wall surface, which is the mounting surface, using screws or the like, the smoke detector 100 can be fixed to the mounting surface. The main body 3 includes a wall portion 3A in which a smoke detection space 33 into which smoke in the smoke passage flows is formed inside, and an upper surface portion 3B to which the upper end of the wall portion 3A is connected. Further, the main body 3 has an opening on the side of the base portion 12 so that a battery can be inserted, and includes a concave battery accommodation portion 3C for accommodating the battery, and a concave speaker accommodation portion 3D formed by an annular wall in which the speaker 8 is accommodated. Also, in FIG. 4, a printed circuit board installation portion 3P is provided in the left direction of the speaker accommodation portion 3D. This printed circuit board installation portion 3P is a wall having a predetermined height similar to a partition wall 3E2 described later, and is formed in a substantially U shape according to the shape of the substrate 6, and the mounting surface side of the substrate 6 is accommodated in the space thereof. The substrate 6 is installed on the printed circuit board installation portion 3P and the partition wall 3E2. The height of the wall of the printed circuit board installation portion 3P is such that a shield case 6F described later can be accommodated.

[0014] The wall portion 3A has the substrate 6 provided on a part of its periphery. The wall portion 3A includes a wall portion a, a wall portion b, a wall portion c, and a wall portion d. The wall portion a is connected to one end portion of the wall portion c and one end portion of the wall portion d. The wall portion b is connected to the other end portion of the wall portion c and the other end portion of the wall portion d. A first hole portion 31 through which light irradiated from the light emitting portion 6A passes is formed in the wall portion c, and a second hole portion 32 through which light received by the light receiving portion 6B passes is formed in the wall portion d. Further, the wall portion 3A is provided with a pair of protruding portions 34 as light shielding columns for preventing the direct light of the light emitting portion 6A from entering the light receiving portion 6B.

[0015] The main body 3 is equipped with a partition wall 3E1 that separates the side where the battery is located from the side where the circuit board 6 is located. In other words, the circuit board 6 is located on the upper surface 3B side of the main body 3, and the battery is located on the back side of the circuit board. The main body 3 is also equipped with a partition wall 3E2 connected to the wall 3A. The circuit board 6 (part of the circuit board with the light-emitting part) is located directly below the lower end of the partition wall 3E2. The partition wall 3E2 has the function of blocking the light from the light-emitting part 6A. Here, the partition wall 3E2 and the circuit board 6 are separate components. Therefore, a gap is formed between the lower end of the partition wall 3E2 and the mounting surface 6a, which is the upper surface of the circuit board 6. To prevent the light from the light-emitting part 6A from leaking through this gap, the smoke detector 100 is equipped with a light-shielding part 30 that has a light-shielding function.

[0016] The light-shielding portion 30 is a plate-shaped member that extends in the vertical direction. In other words, the light-shielding portion 30 extends to the lower side of the slit 6E. That is, when the substrate 6 is mounted on the partition wall 3E2 of the main body 3, the light-shielding portion 30 has a height such that its lower end protrudes slightly from the lower surface (back surface 6b) of the substrate 6. Therefore, even if one tries to look at the light-emitting portion 6A through the gap between the lower end of the partition wall 3E2 and the mounting surface 6a, which is the upper surface of the substrate 6, the light-emitting portion 6A is hidden by the light-shielding portion 30. In this way, by providing the light-shielding portion 30, it is possible to block the light from the light-emitting portion 6A to the light-receiving portion 6B outside the wall portion 3A. Furthermore, it suppresses light from leaking from the light-emitting portion 6A through the gap between the lower end of the partition wall 3E2 and the mounting surface 6a, which is the upper surface of the substrate 6, and from leaking to the light-receiving portion 6B.

[0017] For example, a flat plate-shaped member can be used for the light-shielding portion 30. The light-shielding portion 30 is formed to protrude from the smoke detection space 33 side to the substrate 6 side. The light-shielding portion 30 is attached to the light-emitting portion 6A. In other words, the distance from the light-shielding portion 30 to the light-emitting portion 6A is shorter than the distance from the light-shielding portion 30 to the light-receiving portion 6B. Furthermore, the light-shielding portion 30 is connected to the wall portion 3A, so that the light from the light-emitting portion 6A does not leak from the boundary between the light-shielding portion 30 and the wall portion 3A. The light-shielding portion 30 is connected to the connection portion between wall portion b and wall portion c. The light-shielding portion 30 extends parallel to, for example, the optical axis of the light-emitting portion 6A.

[0018] The lid portion 4 comprises an optical table 4A on which an optical table cover 5 is provided, and a through hole 4B formed in the optical table 4A. The optical table cover 5 and a labyrinth wall are provided on the lower side of the optical table 4A. The smoke detection space 33, a substrate 6, and a wall portion 3A are provided on the upper side of the optical table 4A (see Figure 11). The through hole 4B connects the space inside the optical table cover 5 to the smoke detection space 33. The lid portion 4 also includes a wall portion housing portion 4C that accommodates the wall portion 3A, etc. The wall portion housing portion 4C is formed to be slightly larger on the inside than the wall portion 3A, etc., and is provided around the wall portion 3A, etc. The optical table cover 5 is a flat plate-shaped member. The upper part of the optical table cover 5 is provided with a cylindrical insect screen. Multiple holes are formed in the insect screen for smoke to pass through. The labyrinth wall is housed inside the optical table cover 5 and the insect screen.

[0019] The substrate 6 is provided parallel to the mounting surface, such as a ceiling. The base portion 12 is mounted horizontally to the mounting surface, and the main body 3 is mounted horizontally to the base portion 12. The substrate 6 is mounted horizontally to the main body 3. Therefore, the substrate 6 is provided parallel to the mounting surface. The substrate 6 also includes an optical system arrangement portion 6C where the light-emitting portion 6A and the light-receiving portion 6B are arranged. The optical system arrangement portion 6C is a concave notch formed to match the circumferential shape of the wall portion 3A. The optical system arrangement portion 6C is provided around the wall portion 3A. Specifically, the optical system arrangement portion 6C is provided on the outer circumferential surfaces of wall portion b, wall portion c, and wall portion d. The optical system arrangement portion 6C includes a light-emitting portion arrangement portion 6D1 where the light-emitting portion 6A is arranged, and a light-receiving portion arrangement portion 6D2 where the light-receiving portion 6B is arranged (see Figure 9). Furthermore, a slit 6E into which the light-shielding portion 30 is inserted is formed in the substrate 6 (see Figure 10). The slit 6E has a shape that matches the horizontal cross-sectional shape of the light-shielding portion 30. On the substrate 6, an amplification circuit for amplifying the signal detected by the light-receiving portion 6B and a control device (not shown), such as a microcontroller, for controlling the operation of the light-emitting portion 6A and the light-receiving portion 6B are provided on the light-receiving portion 6B side.

[0020] The light-emitting section 6A can be made up of, for example, an LED. The light-receiving section 6B can be made up of, for example, a photodiode. The light-emitting section 6A and the light-receiving section 6B are mounted on the mounting surface 6a of the substrate 6. In other words, the light-emitting section 6A and the light-receiving section 6B are chip components that do not have lead wires. More specifically, the light-emitting section 6A includes a chip-type LED, and the light-receiving section 6B includes a chip-type photodiode. This makes it possible to make the substrate 6 thinner. At least one of the light-emitting section 6A and the light-receiving section 6B must be a chip component. To explain in more detail, since the light-emitting section 6A and the light-receiving section 6B are chip components, they do not have lead wires and are installed directly on the substrate 6, so their protrusion height from the substrate 6 is low. Since the height of the chip components themselves is approximately the same as the thickness of the substrate 6, the size of the optical system consisting of a pair of light-emitting elements and a light-receiving element of the smoke detector can be reduced. The light-emitting section 6A and the light-receiving section 6B are surface-mounted chip components on the substrate, and the optical axes of these chip components are parallel to the mounting surface 6a of the substrate 6. A smoke detection space 33 exists in front of the first hole 31 of the light-emitting section 6A. In other words, the smoke detection space 33 and the optical system are located on almost the same plane, as shown in Figure 11, and their positions in the height direction are the same. The height of the wall section 3A is the height of the smoke detection space 33, but when the substrate 6 is installed in the printed circuit board installation section 3P, the height from the top surface 3B of the main body 3 to the back surface 6b of the substrate 6 is formed to be slightly lower than the height of the smoke detection space 33.

[0021] The smoke detector 100 is equipped with a shielding case 6F that prevents the light-receiving unit 6B from detecting noise. The shielding case 6F is fixed on the circuit board 6. The shielding case 6F covers and protects the light-receiving unit 6B, the amplification circuit, and the control device. The shielding case 6F has a rectangular box shape and can be manufactured by bending sheet metal, making it easy to assemble.

[0022] Referring to Figure 8, the shield case 6F is provided so as to cover a part of the substrate 6. The shield case 6F is, for example, a box shape with one side open. The shield case 6F comprises a top surface 6F1 provided above the light-receiving unit 6B and a front surface 6F2 in which a circular through-hole 6F3 is formed. The top surface 6F1 faces the mounting surface 6a of the substrate 6. The front surface 6F2 is provided between the light-receiving unit 6B and the wall d. The center of the second hole 32 and the center of the through-hole 6F3 coincide. The upper end of the front surface 6F2 is connected to the top surface 6F1. The lower end 6F4 of the front surface 6F2 extends below the surface of the substrate 6 on which the light-receiving unit 6B is provided. That is, the lower end 6F4 of the front surface 6F2 extends below the mounting surface 6a. The lower end 6F4 of the front surface 6F2 extends to, for example, the back surface 6b of the mounting surface 6a of the substrate 6.

[0023] Figure 7 is a side cross-sectional view showing a smoke detector 100 according to Embodiment 1 of the present invention, and is a diagram showing the light-emitting section 6A. Figure 7 is a cross-sectional view of BB in Figure 6. As shown in Figure 7, the light-emitting section 6A is a chip component provided on the outer edge of the substrate 6. As shown in Figures 6 and 7, a light-emitting notch 40 is formed below the light-emitting section 6A on the substrate 6. If there is a substrate 6 without a notch directly below the light-emitting section 6A provided on the outer edge of the substrate 6, the light emitted downward from the light-emitting section 6A is diffusely reflected by the substrate 6, and the direction of light propagation is not determined. In contrast, in Embodiment 1, since a light-emitting notch 40 is formed below the light-emitting section 6A, the light emitted downward from the light-emitting section 6A is not diffusely reflected by the substrate 6, and travels straight downward through the light-emitting notch 40. Therefore, unwanted diffuse reflection of light can be suppressed. The light-emitting section 6A, which consists of chip components, is composed of a main body installed on the substrate and a light-emitting element provided in front of the main body that emits light. The width of the light-emitting notch 40 is the same as, or slightly larger than, the width of, this light-emitting element. As stated, the light-emitting section 6A is installed on the outer edge of the substrate 6, but to explain in more detail, as shown in Figures 9 and 10, only the light-emitting element is installed so that it is located on the light-emitting notch 40.

[0024] Figure 8 is a side cross-sectional view showing a smoke detector 100 according to Embodiment 1 of the present invention, and is a diagram showing the light-receiving unit 6B. Figure 8 is a cross-sectional view of CC of Figure 6. As shown in Figure 8, the light-receiving unit 6B is a chip component provided on the outer edge of the substrate 6. As shown in Figures 6 and 8, a light-receiving notch 41 is formed in front of and below the light-receiving unit 6B on the substrate 6. Here, the shield case 6F covers the light-receiving unit 6B, the control device and the amplification circuit, and the tip on the light-receiving unit 6B side is inserted into the light-receiving notch 41. In this way, by extending the tip of the shield case 6F on the light-receiving unit 6B side, an area for forming a through hole 6F3 can be secured.

[0025] Figure 9 is a top cross-sectional view showing a smoke detector 100 according to Embodiment 1 of the present invention, and is an enlarged view of Figure 6. Figure 10 is a top view showing the substrate 6 of the smoke detector 100 according to Embodiment 1 of the present invention. As described above, the substrate 6 has a light-emitting notch 40 and a light-receiving notch 41 formed therein, as shown in Figures 9 and 10. In Figure 10, for convenience, the positions where the light-emitting part 6A and the light-receiving part 6B are arranged are indicated by dotted lines. Now, the substrate 6 will be described using Figure 10. The substrate 6 is formed in a substantially rectangular shape, and a large notch that will become the optical system arrangement part 6C is formed on one end of its long side. This notch is formed in a substantially trapezoidal shape with the outer side being longer, corresponding to the shape of the wall part 3A. More specifically, the protruding part 34 that will become the light-shielding column in the wall part 3A engages with the notch portion of the substrate 6. The notch of the substrate 6 is further provided with a light-emitting notch 40, a light-receiving notch 41, and a slit 6E extending inward from the substrate 6.

[0026] Next, the operation of the smoke detector 100 will be explained. When a fire occurs, smoke flows into the smoke passage through the opening 1 of the housing 10. The smoke that flows into the smoke passage flows into the space inside the optical table 4A through the holes in the insect screen on the optical table cover 5. The smoke that flows into the space inside the optical table 4A passes through the labyrinth wall and then flows into the through hole 4B of the lid 4. The smoke that flows into the through hole 4B flows into the smoke detection space 33. Note that the smoke contains fine particles. These particles are heavier than the smoke and therefore do not rise easily. As a result, these particles remain in the optical table 4A, and only the smoke flows into the smoke detection space 33. This improves the accuracy of the smoke detector 100 in detecting fires.

[0027] The light-emitting unit 6A emits light into the smoke detection space 33 through the first hole 31. Here, most of the light emitted from the light-emitting unit 6A enters the smoke detection space 33. However, a portion of the light emitted from the light-emitting unit 6A travels away from the optical axis of the light-emitting unit 6A and does not enter the smoke detection space 33. The light that does not enter the smoke detection space 33 is blocked by the light-shielding unit 30, and leakage of the light that does not enter the smoke detection space 33 through the gap between the partition wall 3E2 and the substrate 6 is suppressed. When smoke flows into the smoke detection space 33, the light emitted from the light-emitting unit 6A is scattered by the smoke. The light-receiving unit 6B detects this scattered light, and the smoke detector 100 detects a fire.

[0028] According to this embodiment 1, the substrate 6 is provided horizontally with respect to the mounting surface. This allows the height of the smoke detector 100 to be kept low. In addition, since the optical system (light-emitting section 6A, light-receiving section 6B) provided on the substrate 6 is made of chip components that do not have lead wires extending in the height direction of the smoke detector 100, the optical system provided on the substrate 6 hardly protrudes from the surface of the substrate 6. Therefore, the smoke detector 100 can be made thinner. Furthermore, the light-emitting section 6A is a chip component provided on the outer edge of the substrate 6, and a light-emitting notch 40 is formed below the light-emitting section 6A on the substrate 6. If there is a substrate 6 without a notch directly below the light-emitting section 6A, the light emitted downward from the light-emitting section 6A is diffusely reflected on the substrate 6, and the direction of light propagation is not determined. In contrast, in this embodiment 1, since a light-emitting notch 40 is formed below the light-emitting section 6A, the light emitted downward from the light-emitting section 6A is not diffusely reflected on the substrate 6 and continues to propagate downward. Therefore, the light is not blocked, and unwanted diffuse reflection of light can be suppressed. This makes it possible to sufficiently secure the signal component while suppressing the noise component of the light-receiving unit 6B when detecting smoke in an optical system having a surface-mounted light-emitting unit 6A. Therefore, the S / N ratio required for smoke detection can be obtained. Conventional light-emitting elements are DIP components with lead wires, so there was no need to consider diffuse reflection because the distance between the light-emitting element and the substrate was large. However, by providing a light-emitting notch 40 when mounting the light-emitting unit 6A directly on the substrate, this problem of diffuse reflection can be solved.

[0029] To accurately detect smoke, it is desirable to match the height of the light-emitting part 6A with the height of the light-receiving part 6B. It is not necessary for the optical axes of the light-emitting part 6A and the light-receiving part 6B, which extend horizontally, to be at exactly the same height, but it is desirable for their optical axes to be at approximately the same height. Therefore, if the light-emitting part 6A is a chip component, the position of the light-receiving part 6B must also be lowered to compensate for the lower position of the light-emitting part 6A. When the position of the light-receiving part 6B is lowered, the height of the second hole 32 and the height of the through-hole 6F3 must also be lowered to match the height of the light-receiving part 6B. Here, if the lower end 6F4 of the front part 6F2 of the shield case 6F is above the mounting surface 6a of the substrate 6, the front part 6F2 may deform when forming the through-hole 6F3 in the front part 6F2. Also, if the lower end 6F4 of the front part 6F2 of the shield case 6F is above the mounting surface 6a, it may not be possible to form the through-hole 6F3 in the front part 6F2. If the front section 6F2 deforms or the shape of the through-hole 6F3 deforms, the light-receiving characteristics of the light-receiving section 6B change, and the smoke detector 100 will no longer be able to accurately detect smoke.

[0030] In this embodiment 1, the lower end 6F4 of the front portion 6F2 of the shield case 6F of the smoke detector 100 extends downward from the surface of the substrate 6 on which the light-receiving portion 6B is provided. Therefore, deformation of the front portion 6F2 can be suppressed when forming the through hole 6F3 in the front portion 6F2. In addition, the shape of the through hole 6F3 can be more reliably determined to be a predetermined shape, such as a circle. The optical axis extending horizontally from the light-receiving portion 6B and the height of the through hole 6F3 provided in the shield case 6F are at the same height. In this way, the shield case 6F with the through hole 6F3 can be provided in front of the light-receiving portion 6B, so that the light-receiving portion 6B can be protected from noise, and therefore the smoke detector 100 can suppress a decrease in smoke detection accuracy. Even if neither the light-emitting portion 6A nor the light-receiving portion 6B is a chip component, the smoke detector 100 can still achieve the effect of suppressing a decrease in smoke detection accuracy, but the effect is further enhanced if both the light-emitting portion 6A and the light-receiving portion 6B are chip components.

[0031] The lower end 6F4 of the front portion 6F2 of the shield case 6F extends downward from the surface of the substrate 6 on which the light-receiving portion 6B is located, that is, it extends downward from the mounting surface 6a, and its lower end 6F4 has a length that extends to the back surface 6b of the substrate 6. Therefore, even if noise light that could not be blocked by the light-shielding portion 30 enters the light-receiving portion 6B side through the gap between the partition wall 3E2 and the substrate 6, it is possible to further suppress the detection of noise light by the light-receiving portion 6B. Conventional light-receiving elements are DIP components with lead wires, so the distance between the light-receiving element and the substrate is large, allowing for the free formation of through-holes for the light-receiving element in the shield case installed at the front. However, when mounting the light-receiving unit 6B directly on the substrate, providing a light-receiving notch 41 ensures sufficient length (height) of the shield case on the front side, allowing for the formation of through-holes for the light-receiving element without any problems. Incidentally, since the amount of light received by the light-receiving unit 6B is inversely proportional to the square of the distance, the position closest to the edge of the substrate 6 receives the most light within the space enclosed between the shield case 6F and the substrate 6. Therefore, in order to increase the amount of light received from scattered light due to smoke, it is desirable to install the light-receiving unit 6B on the outer edge of the substrate 6. On the other hand, the shield case 6F needs to be provided in front of the light-receiving unit 6B. In this embodiment, a light-receiving notch 41 is provided in front of the part of the substrate 6 where the light-receiving unit 6B is installed, and the front part 6F2 of the shield case, which is bent from the top surface 6F1, is passed through the light-receiving notch 41. The width of the front part 6F2 is slightly smaller than the width of the light-receiving notch 41, so that the front part 6F2 can be inserted into the light-receiving notch 41. In this way, the light-receiving unit 6B can be installed on the outer edge of the substrate 6, and the shield case 6F can be provided in front of the light-receiving unit 6B without taking up extra space. The width of the light-receiving notch 41 can be changed as appropriate, but it has a shape that is wider than the width of the light-emitting notch 40.

[0032] As described above, the amount of light received by the light-receiving unit 6B is inversely proportional to the square of the distance, so the position closest to the edge of the substrate 6 receives the most light within the space enclosed between the shield case 6F and the substrate 6. In this embodiment 1, since the light-receiving unit 6B is positioned inside the edge of the substrate 6, collisions between the shield case 6F and the light-receiving unit 6B during assembly are suppressed, and damage to the lens portion of the light-receiving unit 6B is suppressed. Furthermore, since there is no cutout directly below the shield case 6F on the substrate 6, the shielding effect of the substrate 6 is maximized, stray light from the light-emitting unit 6A does not enter, and noise components can be suppressed.

[0033] An amplification circuit and the like are provided around the light-receiving unit 6B. Therefore, the number of wires around the light-receiving unit 6B is greater than the number of wires around the light-emitting unit 6A. If the light-shielding unit 30 is installed alongside the light-receiving unit 6B, it is necessary to form a slit 6E around the light-receiving unit 6B. Therefore, if the light-shielding unit 30 is installed alongside the light-receiving unit 6B, the length of the wires around the light-receiving unit 6B will increase or the wiring pattern will become more complex due to the need to bypass the slit 6E. In the smoke detector 100 according to this embodiment, the light-shielding unit 30 of the circuit board 6 is installed alongside the light-emitting unit 6A. Therefore, the smoke detector 100 can suppress the length of the wires around the light-receiving unit 6B and the complexity of the wiring pattern. In this embodiment, a smoke detector of a type commonly called a fire alarm, equipped with a battery and a speaker, was described as an example. However, the present invention can be applied to smoke detectors of a type in which power is supplied via a signal line. [Explanation of symbols]

[0034] 1 Opening, 3 Main body, 3A Wall section, 3B Top section, 3C Battery housing section, 3D Speaker housing section, 3E1 Partition wall, 3E2 Partition wall, 4 Cover section, 4A Optical bench, 4B Through hole, 4C Wall housing section, 5 Optical bench cover, 6 Circuit board, 6A Light-emitting section, 6B Light-receiving section, 6C Optical system arrangement section, 6D1 Light-emitting section arrangement section, 6D2 Light-receiving section arrangement section, 6E Slit, 6F Shield case, 6F1 Top section, 6F2 Front section, 6F3 Through hole, 6F4 Bottom end, 6a Mounting surface, 6b Back side, 8 Speaker, 10 Housing, 11 First cover, 11A Bottom section, 11A1 Opening for push button, 11B Side section, 11C Corner section, 12 Base section, 30 Light-shielding section, 31 1. First hole, 32. Second hole, 33. Smoke detection space, 34. Protrusion, 40. Light-emitting notch, 41. Light-receiving notch, 100. Smoke detector, a. Wall section, b. Wall section, c. Wall section, d. Wall section.

Claims

1. A housing that is mounted on a surface to be mounted and has a smoke detection space formed inside for detecting smoke, A light-emitting unit that illuminates the smoke detection space, A light receiving unit that receives light irradiated from the light-emitting unit and scattered in the smoke detection space, A smoke detector comprising a circuit board provided inside the housing on which the light-emitting unit and the light-receiving unit are mounted, It comprises a base portion that is attached to the mounting surface, The housing comprises a main body on which the wall portion forming the smoke detection space is formed, The main body is attached to the base portion, The wall portion forming the smoke detection space is not provided on the substrate, but is provided at approximately the same height as the substrate, and is provided so as to be sandwiched between the light-emitting portion and the light-receiving portion mounted on the substrate. A smoke detector characterized by the following features.

2. A housing that is attached to a mounting surface and has a smoke detection space formed inside for detecting smoke, A light-emitting unit that illuminates the smoke detection space, A light receiving unit that receives light irradiated from the light-emitting unit and scattered in the smoke detection space, A smoke detector comprising a circuit board provided inside the housing on which the light-emitting unit and the light-receiving unit are mounted, It comprises a base portion that is attached to the mounting surface, The housing comprises a main body on which the wall portion forming the smoke detection space is formed, The main body is attached to the base portion, The wall portion forming the smoke detection space is provided at approximately the same height as the substrate. The light-emitting unit and the light-receiving unit mounted on the substrate are provided on the outer periphery side of the wall portion. The aforementioned wall portion is A wall portion having a first hole through which light emitted from the light-emitting portion passes, The light receiving portion comprises a wall portion having a second hole through which the light received by the light receiving portion passes. A smoke detector characterized by the following features.

3. A housing that is attached to a mounting surface and has a smoke detection space formed inside for detecting smoke, A light-emitting unit that illuminates the smoke detection space, A light receiving unit that receives light irradiated from the light-emitting unit and scattered in the smoke detection space, A smoke detector comprising a circuit board provided inside the housing on which the light-emitting unit and the light-receiving unit are mounted, The housing comprises a main body on which the wall portion forming the smoke detection space is formed, The wall portion forming the smoke detection space is provided at approximately the same height as the substrate. The light-emitting unit and the light-receiving unit mounted on the substrate are provided on the outer periphery side of the wall portion. The substrate has a concave notch formed therein. The notch is formed in a roughly trapezoidal shape with the outer side being longer, corresponding to the shape of the wall portion. A smoke detector characterized by the following features.

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