JP7553666B2 - Smoke detectors - Google Patents

Description

The present invention relates to a smoke detector that detects smoke generated by a fire or the like.

Conventionally, photoelectric smoke detectors are known as smoke detectors that detect smoke generated by fires, etc. When smoke enters a smoke detection space, light emitted from a light-emitting element is scattered by the smoke and reaches a light-receiving element, thereby detecting smoke. Patent Document 1 discloses a smoke detector that is attached to a mounting surface such as a ceiling, and is a chip component in which the light-emitting element and light-receiving element are surface-mounted on a board. In Patent Document 1, the board is provided perpendicular to the mounting surface.

Japanese Patent No. 5562097 (e.g., FIG. 7)

However, in the smoke detector disclosed in Patent Document 1, the board is attached perpendicular to the mounting surface, which makes the overall height of the smoke detector large. For this reason, there is a demand for a smaller smoke detector.

The present invention aims to solve the above problems by providing a smoke detector that can be made compact.

The smoke detector of the present invention is a smoke detector that is attached to a mounting surface and includes a housing having a smoke detection space formed therein 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 board that is provided inside the housing and on which the light-emitting unit and the light-receiving unit are mounted. The housing includes a main body in which a wall portion that forms the smoke detection space is formed, and a concave cutout portion is formed in the board, and the wall portion is provided with the board on a part of the periphery and the wall portion is provided within the cutout portion.

According to the present invention, the substrate is provided horizontally on the mounting surface, which makes it possible to reduce the height of the smoke detector and therefore the size of the smoke detector.
Furthermore, if the optical axis of the chip component is perpendicular to the board, the smoke detection space will become larger in the height direction; however, in the present invention, the optical axis of the chip component is parallel to the board, so there is no need to increase the height of the smoke detection space, and the smoke detector can be made smaller.

1 is an assembled perspective view showing a smoke detector 100 according to a first embodiment of the present invention. 1 is a top view showing a smoke detector 100 according to a first embodiment of the present invention. 1 is a side view showing a smoke detector 100 according to a first embodiment of the present invention. 1 is an exploded perspective view showing a smoke detector 100 according to a first embodiment of the present invention. 1 is a perspective cross-sectional view showing a smoke detector 100 according to a first embodiment of the present invention. 1 is a top cross-sectional view showing a smoke detector 100 according to a first embodiment of the present invention. 1 is a side cross-sectional view showing a smoke sensor 100 according to a first embodiment of the present invention, and shows a light-emitting unit 6A. FIG. 1 is a side cross-sectional view showing a smoke sensor 100 according to a first embodiment of the present invention, and shows a light receiving section 6B. FIG. FIG. 7 is a top cross-sectional view showing the smoke detector 100 according to the first embodiment of the present invention, and is an enlarged view of FIG. 6. 2 is a top view showing the substrate 6 of the smoke sensor 100 according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view showing a schematic positional relationship between a substrate 6, a smoke detection space 33, and an optical bench 4A in a smoke detector 100 according to the first embodiment of the present invention. FIG.

Embodiment 1.
Hereinafter, an embodiment of a smoke detector according to the present invention will be described with reference to the drawings. Fig. 1 is an assembled perspective view showing a smoke detector according to embodiment 1 of the present invention, Fig. 2 is a top view showing the smoke detector according to embodiment 1 of the present invention, and Fig. 3 is a side view showing the smoke detector according to embodiment 1 of the present invention. Fig. 4 is an exploded perspective view showing the smoke detector according to embodiment 1 of the present invention, Fig. 5 is a perspective cross-sectional view showing the smoke detector according to embodiment 1 of the present invention, and Fig. 6 is a top cross-sectional view showing the smoke detector according to embodiment 1 of the present invention. Fig. 6 is a cross-sectional view taken along line A-A in Fig. 3.

As shown in Figures 1 to 6, the smoke detector 100 is installed in a monitored space, such as the interior of a house, on a mounting surface, such as a ceiling. The smoke detector 100 also has a housing 10 including a cylindrical first cover 11 with a bottom and a base portion 12 provided on the back side of the first cover 11. The smoke detector 100 includes a main body 3 that is housed in the housing 10 and divides the space inside the housing 10 into upper and lower portions, 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 that is housed within the optical bench cover 5 and has a light-shielding function. A smoke detection space 33 that detects smoke is also formed inside the housing 10, which will be described in detail later.

Furthermore, the smoke detector 100 is equipped with a board 6 provided between the main body 3 and the lid 4, a battery that supplies operating power to the various circuits provided on the board 6, and a speaker 8 that outputs sound and the like. On the surface of the board 6, a light-emitting unit 6A that irradiates light into a smoke detection space 33 that detects smoke, and a light-receiving unit 6B that receives light irradiated from the light-emitting unit 6A and scattered in the smoke detection space 33 are mounted.

The first cover 11 of the housing 10 has openings 1 that extend in the circumferential direction. The openings 1 are formed in two rows in the vertical direction. The openings 1 communicate with the smoke passage inside the housing 10. The first cover 11 also has a flat bottom surface 11A in which an opening 11A1 for a push button is formed, a cylindrical side surface 11B, and an annular corner 11C that connects the bottom surface 11A and the side surface 11B. The bottom surface 11A faces the main body 3.

The base portion 12 of the housing 10 is provided on the upper part of the first cover 11. The base portion 12 can be fixed to the mounting surface, such as a ceiling surface or a wall surface, by fixing the base portion 12 with screws or the like. The main body 3 has a wall portion 3A inside which a smoke detection space 33 into which smoke from the smoke passage flows is formed, and an upper surface portion 3B to which the upper end of the wall portion 3A is connected. The main body 3 also has an opening on the side of the base portion 12 so that a battery can be inserted, a concave battery housing portion 3C for housing the battery, and a concave speaker housing portion 3D formed by an annular wall in which the speaker 8 is housed.
4, a printed circuit board installation section 3P is provided to the left of the speaker housing section 3D. This printed circuit board installation section 3P is a wall having a predetermined height, similar to a partition wall 3E2 described later, and is formed in a substantially U-shape to match the shape of the board 6, with the mounting surface side of the board 6 housed within the space. The board 6 is installed on the printed circuit board installation section 3P and the partition wall 3E2. The height of the wall of the printed circuit board installation section 3P is set to a height that can house a shield case 6F described later.

The wall 3A has a substrate 6 on a part of its periphery. The wall 3A has walls a, b, c, and d. Wall a is connected to one end of wall c and one end of wall d. Wall b is connected to the other end of wall c and the other end of wall d. Wall c has a first hole 31 through which the light emitted from the light emitting unit 6A passes, and wall d has a second hole 32 through which the light received by the light receiving unit 6B passes. Wall 3A also has a pair of protrusions 34 as light shielding columns that prevent the straight light from the light emitting unit 6A from entering the light receiving unit 6B.

The main body 3 is provided with a partition wall 3E1 that separates the side where the battery is located from the side where the board 6 is provided. In other words, the board 6 is provided on the upper surface 3B side of the main body 3, and the battery is provided on the back side of the board 6. The main body 3 also has a partition wall 3E2 that is connected to the wall 3A. The board 6 (a part of the board on which the light-emitting part is located) is provided directly below the lower end of the partition wall 3E2. The partition wall 3E2 has the function of blocking light from the light-emitting part 6A. Here, the partition wall 3E2 and the board 6 are separate bodies. 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 board 6. The smoke detector 100 is provided with a light-blocking part 30 that has a light-blocking function so that the light from the light-emitting part 6A does not leak from the gap.

The light shielding portion 30 is a plate-like member extending 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 board 6 is attached to the partition wall 3E2 of the main body 3, the light shielding portion 30 has a height such that the lower end of the light shielding portion 30 can slightly protrude from the lower surface (rear surface 6b) of the board 6. Therefore, even if the light emitting portion 6A is viewed from the gap between the lower end of the partition wall 3E2 and the mounting surface 6a, which is the upper surface of the board 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 light from the light emitting portion 6A to the light receiving portion 6B outside the wall portion 3A. In addition, the light of the light emitting portion 6A leaks from the gap between the lower end of the partition wall 3E2 and the mounting surface 6a, which is the upper surface of the board 6, and the light leakage to the light receiving portion 6B side is suppressed.

The light shielding portion 30 may be, for example, a flat plate-shaped member. The light shielding portion 30 is formed so as to protrude from the smoke detection space 33 side toward the substrate 6 side. The light shielding portion 30 is provided next 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. The light shielding portion 30 is connected to the wall portion 3A so that the light of 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 the wall portion b and the wall portion c. The light shielding portion 30 extends parallel to, for example, the optical axis of the light emitting portion 6A.

The lid 4 includes an optical bench 4A on which an optical bench cover 5 is provided, and a through hole 4B formed in the optical bench 4A. The optical bench cover 5 and a labyrinth wall are provided below the optical bench 4A. The smoke detection space 33, the substrate 6, and the wall 3A are provided above the optical bench 4A (see FIG. 11). The through hole 4B connects the space inside the optical bench cover 5 to the smoke detection space 33. The lid 4 also includes a wall housing 4C that houses the wall 3A, etc. The wall housing 4C is formed with an inner side that is slightly larger than the wall 3A, etc., and is provided around the wall 3A, etc. The optical bench cover 5 is a flat plate-shaped member. A cylindrical insect screen is provided on the upper part of the optical bench cover 5. The insect screen has a plurality of holes through which smoke passes. The labyrinth wall is housed inside the optical bench cover 5 and the insect screen.

The substrate 6 is provided horizontally and parallel to the mounting surface such as the ceiling surface. The base portion 12 is attached horizontally to the mounting surface, and the main body 3 is attached so as to be horizontal to the base portion 12. The substrate 6 is attached so as to be horizontal to the main body 3. Therefore, the substrate 6 is provided horizontally and parallel to the mounting surface. The substrate 6 also has an optical system arrangement portion 6C in which the light emitting portion 6A and the light receiving portion 6B are arranged. The optical system arrangement portion 6C is a concave cutout portion formed to match the peripheral 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 peripheral surface of the wall portion b, the outer peripheral surface of the wall portion c, and the outer peripheral surface of the wall portion d. The optical system arrangement portion 6C includes the light emitting portion arrangement portion 6D1 in which the light emitting portion 6A is arranged, and the light receiving portion arrangement portion 6D2 in which the light receiving portion 6B is arranged (see FIG. 9). The substrate 6 is also formed with a slit 6E into which the light shielding portion 30 is inserted (see FIG. 10). The slit 6E has a shape that matches the horizontal cross-sectional shape of the light shielding portion 30. The substrate 6 is also provided with an amplifier circuit that amplifies the signal detected by the light receiving portion 6B, and a control device (not shown), such as a microcomputer, that controls the operation of the light emitting portion 6A and the light receiving portion 6B, on the light receiving portion 6B side.

The light emitting unit 6A can be composed of, for example, an LED. The light receiving unit 6B can be composed of, for example, a photodiode. The light emitting unit 6A and the light receiving unit 6B are placed on the mounting surface 6a of the substrate 6. That is, the light emitting unit 6A and the light receiving unit 6B are chip components without lead wires. More specifically, the light emitting unit 6A includes a chip type LED, and the light receiving unit 6B includes a chip type photodiode. This allows the substrate 6 to be made thinner. It is sufficient that at least one of the light emitting unit 6A and the light receiving unit 6B is a chip component. More specifically, the light emitting unit 6A and the light receiving unit 6B, which are chip components, do not have lead wires and are directly installed on the substrate 6, so that the protruding height from the substrate 6 is low. The height of the chip component itself is approximately the same as the thickness of the substrate 6, so that the size of the optical system consisting of a pair of light emitting elements and light receiving elements of the smoke detector can be reduced.
The light emitting unit 6A and the light receiving unit 6B are chip components surface-mounted 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 light emitting unit 6A through the first hole 31. In other words, the smoke detection space 33 and the optical system are provided on approximately the same plane as shown in FIG. 11, and have the same position in the height direction. The height of the wall 3A is the height of the smoke detection space 33, but when the substrate 6 is installed on the printed substrate installation section 3P, the height from the upper surface 3B of the main body 3 to the back surface 6b of the substrate 6 is formed slightly lower than the height of the smoke detection space 33.

The smoke detector 100 is equipped with a shield case 6F that has the function of preventing the light receiving unit 6B from detecting noise. The shield case 6F is fixed onto the substrate 6. The shield case 6F covers and protects the light receiving unit 6B, the amplifier circuit, and the control unit. The shield case 6F has a rectangular box shape and can be made by bending sheet metal, making it easy to assemble.

Referring to FIG. 8, the shield case 6F is provided so as to cover a part of the substrate 6. The shield case 6F is, for example, in the shape of a box with one side open. The shield case 6F includes a top surface 6F1 provided on the upper part of 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 with each other. 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 downward from 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 downward from 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.

Figure 7 is a side cross-sectional view showing a smoke detector 100 according to embodiment 1 of the present invention, and shows the light-emitting unit 6A. Figure 7 is a cross-sectional view taken along the line B-B of Figure 6. As shown in Figure 7, the light-emitting unit 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 unit 6A on the substrate 6. If a substrate 6 without a notch exists directly below the light-emitting unit 6A provided on the outer edge of the substrate 6, the light irradiated downward from the light-emitting unit 6A is diffusely reflected by the substrate 6, and the direction of travel of the light is not determined. In contrast, in this embodiment 1, since the light-emitting notch 40 is formed below the light-emitting unit 6A, the light irradiated downward from the light-emitting unit 6A is not diffusely reflected by the substrate 6, and travels downward as it is through the light-emitting notch 40. Therefore, unnecessary diffuse reflection of light can be suppressed. The light-emitting unit 6A, which is made of a chip component, is composed of a main body that is installed on the substrate and a light-emitting body that is provided in front of the main body and emits light, and the width of the light-emitting notch 40 is formed to be the same as or slightly larger than the width of the light-emitting body. The light-emitting unit 6A is said to be 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 body is installed so that it is located above the light-emitting notch 40.

Figure 8 is a side cross-sectional view showing the smoke detector 100 according to the first embodiment of the present invention, and shows the light receiving unit 6B. Figure 8 is a cross-sectional view taken along the line C-C 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 amplifier circuit, and the tip on the light receiving unit 6B side is inserted into the light receiving notch 41. In this way, the tip on the light receiving unit 6B side of the shield case 6F extends, thereby ensuring an area for forming the through hole 6F3.

9 is a top cross-sectional view of the smoke detector 100 according to the first embodiment of the present invention, and is an enlarged view of FIG. 6. FIG. 10 is a top view of the substrate 6 of the smoke detector 100 according to the first embodiment 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 FIG. 9 and FIG. 10. In FIG. 10, the positions where the light emitting unit 6A and the light receiving unit 6B are arranged are shown by dotted lines for convenience. Here, the substrate 6 will be described with reference to FIG. 10. The substrate 6 is formed in a substantially rectangular shape, and a large notch that becomes the optical system arrangement unit 6C is formed on one end side of the long piece. This notch is formed in a substantially trapezoidal shape with a long outer side, and has a shape that corresponds to the shape of the wall portion 3A. More specifically, the notch of the substrate 6 is shaped to engage with the protrusion 34 side that becomes the light blocking column in the wall portion 3A. The notch in the substrate 6 further includes a light-emitting notch 40, a light-receiving notch 41, and a slit 6E toward the inside of the substrate 6.

Next, the operation of the smoke detector 100 will be described. When a fire or the like 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 bench 4A through holes in the insect screen in the optical bench cover 5. The smoke that flows into the space inside the optical bench 4A passes through the labyrinth wall and then flows into the through hole 4B in 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 smoke and do not rise easily. For this reason, the particles remain on the optical bench 4A, and only the smoke flows into the smoke detection space 33. This improves the fire detection accuracy of the smoke detector 100.

The light-emitting unit 6A irradiates light into the smoke detection space 33 through the first hole 31. Most of the light irradiated from the light-emitting unit 6A enters the smoke detection space 33. However, some of the light irradiated from the light-emitting unit 6A travels in a direction 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 the light that does not enter the smoke detection space 33 is prevented from leaking from the gap between the partition wall 3E2 and the substrate 6. When smoke flows into the smoke detection space 33, the light irradiated 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.

According to the first embodiment, the substrate 6 is provided horizontally relative to the mounting surface. Therefore, the height of the smoke detector 100 can be kept low. In addition, as the optical system (light-emitting unit 6A, light-receiving unit 6B) provided on the substrate 6, a chip component that does not have a lead wire extending in the height direction of the smoke detector 100 is used, so 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 thin. In addition, the light-emitting unit 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 unit 6A on the substrate 6. If a substrate 6 without a notch exists directly below the light-emitting unit 6A, the light irradiated downward from the light-emitting unit 6A is diffusely reflected by the substrate 6, and the direction of travel of the light is not determined. In contrast, in the first embodiment, the light-emitting notch 40 is formed below the light-emitting unit 6A, so that the light irradiated downward from the light-emitting unit 6A is not diffusely reflected by the substrate 6 and travels downward as it is. Therefore, the light is not blocked and unnecessary diffuse reflection of light can be suppressed. As a result, in an optical system having a surface-mounted light-emitting unit 6A, when detecting smoke, the noise components of the light-receiving unit 6B can be suppressed while the signal components are sufficiently secured. Therefore, the S/N ratio required for smoke detection can be obtained. Conventional light-emitting elements are DIP components with lead wires, and since the light-emitting element is far away from the board, there was no need to consider diffuse reflection. However, by providing a light-emitting notch 40 when mounting the light-emitting unit 6A directly on the board, the problem of diffuse reflection can be solved.

In order to detect smoke with high accuracy, it is advisable to align the height position of the light-emitting unit 6A with the height position of the light-receiving unit 6B. It is not necessary to make the height of the optical axis of the light-emitting unit 6A and the optical axis of the light-receiving unit 6B, which extend horizontally, exactly the same, but it is desirable to make the height of the optical axis of both the light-emitting unit 6A and the light-receiving unit 6B almost the same. Therefore, when the light-emitting unit 6A is a chip part, the position of the light-receiving unit 6B must be lowered by the amount that the position of the light-emitting unit 6A is lowered. When the position of the light-receiving unit 6B is lowered, the height position of the second hole portion 32 and the height position of the through hole 6F3 must also be lowered to match the height position of the light-receiving unit 6B. Here, if the lower end 6F4 of the front portion 6F2 of the shield case 6F is above the mounting surface 6a of the board 6, the front portion 6F2 may be deformed when the through hole 6F3 is formed in the front portion 6F2. Also, if the lower end 6F4 of the front portion 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 portion 6F2. If the front portion 6F2 is deformed or the shape of the through hole 6F3 is deformed, the light receiving characteristics of the light receiving portion 6B will change, and the smoke detector 100 will no longer be able to detect smoke accurately.

The lower end 6F4 of the front part 6F2 of the shield case 6F of the smoke detector 100 according to the first embodiment extends downward from the surface of the substrate 6 on which the light receiving part 6B is provided. This makes it possible to prevent the front part 6F2 from being deformed when the through hole 6F3 is formed in the front part 6F2. In addition, the shape of the through hole 6F3 can be more reliably made into a predetermined shape, for example, a circle. The optical axis of the light receiving part 6B extending in the horizontal direction and the height of the through hole 6F3 provided in the shield case 6F are at the same height position. Since the shield case 6F with the through hole 6F3 can be provided in front of the light receiving part 6B in this way, the light receiving part 6B can be protected from noise, and therefore the smoke detector 100 can prevent the smoke detection accuracy from decreasing. Even if either the light emitting part 6A or the light receiving part 6B is not a chip part, the smoke detector 100 can obtain the effect of preventing the smoke detection accuracy from decreasing, but if the light emitting part 6A and the light receiving part 6B are chip parts, the effect is further enhanced.

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 provided, i.e., extends downward from the mounting surface 6a, and the lower end 6F4 has a length that extends to approximately the rear surface 6b of the substrate 6. Therefore, even if noise light that could not be blocked by the light blocking 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 noise light from being detected by the light receiving portion 6B.
Conventional light receiving elements are DIP components with lead wires, and therefore the distance between the light receiving element and the board is great, so that a through hole for the light receiving element could be freely formed in the shielding case installed at the front. However, when mounting the light receiving unit 6B directly on the board, by providing a light receiving notch 41, the length (height) of the shielding case on the front side can be secured, and the through hole for the light receiving element can be formed without any problem.
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 end face of the substrate 6 receives the most light in the space surrounded by the shielding case 6F and the substrate 6, and in terms of increasing the amount of light scattered by smoke received, it is desirable to install the light receiving unit 6B on the outer edge of the substrate 6. On the other hand, it is necessary to provide the shielding case 6F in front of the light receiving unit 6B. Therefore, 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 provided, and the front part 6F2 of the shielding case bent from the top surface part 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 shielding case 6F can be provided in front of the light receiving unit 6B without taking up any extra space. The width of the light-receiving notch 41 can be appropriately changed, but has a shape wider than the width of the light-emitting notch 40 .

As described above, the amount of light received by the light receiving unit 6B is inversely proportional to the square of the distance, so that the position closest to the end face of the substrate 6 receives the greatest amount of light in the space enclosed between the shielding case 6F and the substrate 6. In this embodiment 1, the light receiving unit 6B is positioned inside the end face of the substrate 6, which prevents the shielding case 6F from colliding with the light receiving unit 6B during assembly and prevents damage to the lens portion of the light receiving unit 6B. Furthermore, since the substrate 6 is not cut out directly below the shielding case 6F, the shielding effect of the substrate 6 is maximized, stray light from the light emitting unit 6A is not allowed to enter, and noise components can be suppressed.

An amplifier circuit and the like are provided around the light receiving unit 6B. Therefore, the number of wirings around the light receiving unit 6B is greater than the number of wirings around the light emitting unit 6A. If the light shielding unit 30 is provided next to 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 provided next to the light receiving unit 6B, the length of the wiring around the light receiving unit 6B becomes longer and the wiring pattern becomes more complicated by the amount of detouring the slit 6E. The light shielding unit 30 of the substrate 6 of the smoke detector 100 according to the embodiment is provided next to the light emitting unit 6A. Therefore, the smoke detector 100 can prevent the length of the wiring around the light receiving unit 6B from becoming longer and the wiring pattern from becoming more complicated.
In this embodiment, a smoke detector of the type generally referred to as a fire alarm, which is equipped with a battery and a speaker, has been used as an example. However, the present invention can also be applied to a smoke detector of the type that receives power via a signal line.

1 opening, 3 main body, 3A wall, 3B top surface, 3C battery storage, 3D speaker storage, 3E1 partition wall, 3E2 partition wall, 4 lid, 4A optical stand, 4B through hole, 4C wall storage, 5 optical stand cover, 6 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 surface, 6F2 front surface, 6F3 through hole, 6F4 bottom end, 6a mounting surface, 6b back surface, 8 speaker, 10 housing, 11 first cover, 11A bottom surface, 11A1 opening for push button, 11B side surface, 11C corner, 12 base, 30 light shielding section, 31 First hole, 32 second hole, 33 smoke detection space, 34 protrusion, 40 light emitting notch, 41 light receiving notch, 100 smoke detector, a wall, b wall, c wall, d wall.

Claims (5)

A housing that is attached to a mounting surface and has a smoke detection space formed therein 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;
A substrate provided inside the housing and on which the light emitting unit and the light receiving unit are mounted.
The housing includes a main body on which a wall portion that defines the smoke detection space is formed,
The substrate is provided with a concave cutout portion,
A smoke detector, characterized in that the wall portion has a substrate provided on a part of its periphery, and the wall portion is provided within the cutout portion. The wall portion forming the smoke detection space is not provided on the substrate, but is provided at the same height as the substrate, and the wall portion is provided so as to be sandwiched between a light emitting portion and a light receiving portion mounted on the substrate.
2. The smoke detector according to claim 1. The wall portion is
a wall portion having a first hole portion through which light emitted from the light emitting portion passes;
and a wall portion having a second hole portion through which the light received by the light receiving portion passes.
2. The smoke detector according to claim 1. The recessed portion formed in the substrate is formed in a generally trapezoidal shape with a long outer side, and has a shape corresponding to the shape of the wall portion.
3. The smoke detector according to claim 2. the light emitting portion is a chip component provided on an outer edge portion of the substrate,
A light emitting notch is formed below the light emitting body of the light emitting portion on the substrate.
3. The smoke detector according to claim 2.

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