JP2020067920A - Smoke detector - Google Patents

Abstract

To provide a smoke detector using a chip-type light emitting element or light receiving element which is mounted on a surface of a circuit board without employing a prism lens or a mirror surface treatment.SOLUTION: A smoke detector 1 is configured by a housing 2 and a smoke detector S provided in the housing 2; and the smoke detector S is configured by: a circuit board 3 on which a light emitting element 4 and a light receiving element 5 are mounted; a cylindrical optical stand 6 provided on a lower side of the circuit board 3; a light guide block 7 having a rectangular parallelepiped irradiation light guide path 71 and a light receiving light guide path 72, which are inserted into an insertion portion 61 of an optical bench 6; and an optical bench cover 8. The light guide block 7 comprises the irradiation light guide path 71 that is a space which communicates the light emitting element 4 and a smoke detection area W, and the light receiving light guide path 72 that is a space which communicates the light receiving element 5 and the smoke detection area W, while a surface of a material of the light guide block 7 is made white. Further, a surface of a material of the optical bench 6 which is a structural body including the smoke detection area W is made black.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a smoke detector that detects smoke by irradiating a smoke sensing region with light such as near infrared rays and detecting scattered light from smoke particles with respect to the illuminated light by a light receiving element.

  In smoke detectors that use chip-type light emitting elements or light receiving elements that are surface-mounted on a circuit board, the optical axis is oriented in a direction perpendicular to the surface of the circuit board. Therefore, by reflecting and bending the optical axis with a prism lens or a concave mirror, the smoke sensing area is irradiated with light or scattered light generated in the smoke sensing area is detected (see Patent Documents 1 and 2).

JP, 2016-200979, A JP, 2018-128905, A

  However, using a prism lens in the smoke sensor described in Patent Document 1 causes a problem that the cost is high and the smoke detecting function of the smoke sensor is significantly deteriorated when the smoke sensor becomes cloudy due to dust or deterioration over time. Further, in the smoke detector in which the concave mirror shown in Patent Document 2 is provided in the guide hole (light guide path), the concave mirror is formed of a metal plating film on the concave portion of the inner wall surface of the guide hole. However, there is a problem in that it takes time and cost to perform the plating process in the deep inside of the narrow guide hole.

  Therefore, an object of the present invention is to provide a smoke sensor that uses a chip-type light emitting element or light receiving element that is surface-mounted on a circuit board without using a prism lens or mirror surface treatment.

  The present invention relates to a circuit board on which electric parts for realizing the function of detecting smoke are mounted, a light emitting element mounted on the circuit board for emitting light for detecting smoke, and a smoke flowing in from the outside. A smoke detector comprising: a smoke sensing region that irradiates light from a light emitting element to obtain scattered light; and a light receiving element that is mounted on the circuit board to receive the scattered light. And a light guide block having at least one of a light guide path for irradiation which is a space communicating with the smoke sensing area or a light receiving light guide path which is a space communicating the light receiving element and the smoke sensing area. At least the surface of the material of the optical bench, which is a structure including the sensing region, is configured with an absorption color that absorbs the light emitted by the light emitting element, and at least the surface of the material of the light guide block is configured with a non-absorption color. ing A smoke detector, wherein the door.

  In the specification of the present application, "mounting on a circuit board" means through-hole mounting in which electric wires are fixed to holes in the board by using lead wires on the circuit board, or electric parts are mounted on the surface of the board by using cream solder. Including surface mounting for mounting.

  According to the present invention, the optical axis of a light-emitting element in a chip-type LED or the like, which is surface-mounted on a circuit board by an irradiation light guide path provided in a light guide block in which at least the surface of a material is made of non-absorption color, is bent Then, the smoke sensing area can be irradiated from any position. Also, scattered light obtained by irradiating smoke from the outside with light from the light emitting element in the smoke sensing area can be detected by the chip type light receiving element by bending the optical axis of the scattered light by the light receiving guide path. You can Therefore, it can be surface-mounted on a circuit board that can illuminate the smoke sensing area and receive scattered light from the smoke sensing area without using expensive prism lenses or time-consuming and costly mirror finishing. It is possible to provide a smoke sensor using a chip-type light emitting element or light receiving element.

It is a longitudinal cross-sectional view of the smoke sensor 1 according to the first embodiment of the present invention. It is the sectional view on the AA line of the smoke detection part S shown in FIG. It is a perspective view which shows the member (optical stand 6, light guide block 7, optical stand cover 8) which comprises the smoke detection part S shown in FIG. It is a longitudinal cross-sectional view of the smoke detector S1 in Example 2 of the present invention. It is the BB sectional view taken on the line shown in FIG.

  The present invention is a smoke detector. Hereinafter, modes for carrying out the present invention will be described.

  1 is a vertical cross-sectional view of a smoke sensor 1 according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the smoke detector S of FIG. 1 taken along the line AA, and the circuit board 3 of the smoke detector S is not shown. FIG. 3 is a perspective view of members constituting the smoke detector S. 1 and 3 are shown in the vertical direction in a state where the smoke sensor 1 is installed on the ceiling, and FIG. 1 shows a state where the smoke sensor 1 is mounted on a mounting surface 9 of the ceiling. The up-down direction in this specification indicates the positional relationship when the smoke sensor 1 is attached to the ceiling. The smoke detector 1 includes a housing 2 and a smoke detector S provided in the housing 2. The smoke detecting section S includes a circuit board 3, a cylindrical optical stand 6 provided on the lower side of the circuit board 3, a rectangular parallelepiped light guide block 7 inserted into an insertion section 61 of the optical stand 6, and an optical section. It is composed of a base cover 8. The light emitting element 4 and the light receiving element 5 are surface-mounted on the circuit board 3, and the light guide block 7 includes an irradiation light guide path 71 and a light reception light guide path 72. The housing 2 is composed of a main body 21 and a cover 22 fitted to the lower portion of the main body 21. A plurality of smoke inlets 23 are annularly arranged under the cover 22, and smoke generated during a fire flows into the smoke detecting section S from the smoke inlet 23.

  In the configuration of the smoke detector S, the circuit board 3 is attached to the inner bottom surface of the main body 21. The circuit board includes a light emitting element 4, a light receiving element 5, and other electric parts for realizing the function of detecting smoke, such as a light emission control circuit, an amplifier circuit, a fire discrimination circuit, an analog / digital converter, a microcomputer, or the like. Circuit components (not shown) are mounted. The light emitting element 4 and the light receiving element 5 are a chip LED and a chip photodiode, respectively, which emit near-infrared light, and are surface-mounted on the lower surface side of the circuit board 3.

  The optical table 6 is a structure including the smoke sensing area W, and is arranged on the lower side of the circuit board 3, and an insertion part 61 for inserting the light guide block 7 from the upper surface is provided on the upper part of the optical table 6. Has been. Further, the smoke detection chamber 62 opens downward at the lower part of the optical table 6, and the upper part of the smoke detection chamber 62 communicates with the insertion portion 61. The smoke detection chamber 62 includes a smoke sensing area W. The insertion portion 61 is arranged so that the inserted light guide block 7 is located below the light emitting element 4 and the light receiving element 5. The opening 73 of the light guide block 7 is communicated above the smoke detection chamber 62. A partition wall 63 that partitions the center of the opening 73 is provided above the smoke detection chamber 62 and at a position where the opening 73 of the insertion portion 61 is arranged. Further, a plurality of substantially J-shaped wall bodies 64 are provided on the peripheral edge of the lower surface of the optical table 6. The plurality of wall bodies 64 are provided upright in a substantially annular shape with a predetermined space therebetween, and form a labyrinth structure that allows the smoke flowing from the smoke inlet 23 to flow in and blocks external light. Then, the open portion at the lower end of the wall body 64 is covered with a circular optical bench cover 8 with a rim to form a dark room 65. At least the surface of the material of the optical bench 6 and the optical bench cover 8 is made of black which is an absorption color for absorbing the light emitted by the light emitting element 4. The light emitted by the light emitting element 4 is absorbed by the surface of the optical table 6. Therefore, the light reflected by the surface of the optical table 6 is not detected by the light receiving element 5. The smoke sensing area W is an area in which smoke flowing from the outside into the smoke detection chamber 62 is irradiated with light from the light emitting element 4 to obtain scattered light. In the present embodiment, the smoke detection area 62 will be described later. It means a region where the axis L2 and the optical axis L3 intersect.

  The light guide block 7 is provided with an irradiation light guide path 71 and a light reception light guide path 72 inside. The irradiation light guide path 71 is a space communicating from the position of the light emitting element 4, and the light reception light guide path 72 is a space communicating from the position of the light receiving element 5 to the opening 73 provided on the lower surface of the light guide block 7. Further, the opening 73 is arranged above the smoke detection chamber 62 when the light guide block 7 is inserted into the insertion portion 61. The opening 73 is provided with two slopes, and the partition wall 63 is provided between them. The line perpendicular to each slope faces the substantially central direction of the smoke detection chamber 62. Further, a hole 62 a communicating with the irradiation light guide path 71 and a hole 62 b communicating with the light reception light guide path 72 are provided on the upper surface of the smoke detection chamber 62 with the partition wall 63 interposed therebetween. The irradiation light guide path 71 communicates with the hole 61a, and the light reception light guide path 72 communicates with the smoke sensing region W of the smoke detection chamber 62 through the hole 62a. The irradiation light guide path 71 is a communication hole having a substantially quadrangular cross section except for the hole provided on the slope of the opening 73, and is composed of an upper portion 71a, a central portion 71b, and a lower portion 71c. The upper portion 71a is a vertical hole. The central portion 71b has a smaller diameter than the upper portion 71a and has a sloped surface 71d, and is configured so that the diameter becomes smaller toward the lower side. The facing surface of the inclined surface 71d is a substantially V-shaped bent surface that is bent downward from a vertical surface in a direction parallel to the inclined surface 71d. The lower portion 71c is provided in a direction perpendicular to the slope of the opening 73 from the central portion 71b. The optical axis L1 of the light emitted from the light emitting element 4 in the downward vertical direction with respect to the mounting surface 9 is bent in the direction of the optical axis L2 at the inclined surface 71d. The optical axis L2 is irradiated to the smoke sensing area W of the smoke detection chamber 62, and the direction of the optical axis L2 in the smoke sensing area W is an acute angle θ (θ = 35 °) with respect to the horizontal plane of the mounting surface 9. Further, the light receiving light guide path 72 is a communication hole having a shape in which the irradiation light guide path 71 is substantially symmetrical with respect to the vertical plane. The light receiving light guide path 72 includes an upper portion 72a, a central portion 72b, and a lower portion 72c. The upper portion 72a has an upper portion 71a, the central portion 72b has a central portion 71b, and the lower portion 72c has a substantially same shape as the lower portion 71c. The central portion 72b has an inclined surface 72d. When there is smoke, the light of the light emitting element 4 strikes the smoke in the smoke sensing area W and scattered light is generated. The inclined surface 72d bends the obliquely upward optical axis L3 of the scattered light in the direction of the optical axis L4 extending perpendicularly to the mounting surface 9 to the light receiving element 5. The material of the light guide block 7 is white, which is a non-absorption color, and the inner surfaces of the irradiation light guide path 71 and the light reception light guide path 72 are white. Therefore, the inner surfaces of the irradiation light guide path 71 and the light reception light guide path 72 reflect light emitted by the light emitting element 4 and scattered light. Therefore, the light emitted from the light emitting element 4 which travels in the direction of the optical axis L1 is reflected in the direction of the optical axis L2 by the white slope 71d and can be applied to the smoke sensing area W. The scattered light traveling in the direction of the optical axis L3 is reflected by the white slope 72d in the direction of the optical axis L4, reaches the light receiving element 5, and is detected. In this embodiment, the slopes 71d and 72d form an angle of 70 ° with respect to the mounting surface 9 with respect to the horizontal direction. The intersection angle between the optical axis L2 and the optical axis L3 is 70 °.

Next, the operation of the smoke sensor 1 will be described.
In the smoke sensor 1 mounted on the mounting surface 9, the light emitting element 4 is blinking during operation, and the light emitted by the light emitting element 4 is bent at the white sloped surface 71d from the direction of the optical axis L1 to be reflected by the optical axis L2. The light sequentially irradiates the smoke sensing area W in the smoke detection chamber 62. The smoke that has reached the smoke sensor 1 at the time of a fire flows into the smoke detecting chamber 62 from the smoke inlet 23 through the wall 64 of the smoke detecting section S and the dark room 65. The smoke flowing into the smoke detection chamber 62 scatters the light emitted from the light emitting element 4 in the smoke sensing area W to generate scattered light. Then, the scattered light is bent at the white slope 72d from the direction of the optical axis L3, sequentially advances in the direction of the optical axis L4, and reaches the light receiving element 5. Then, by the output of the light receiving element 5 that has detected the scattered light, the fire discrimination circuit mounted on the circuit board 3 detects the occurrence of the fire and transmits the fire occurrence signal to the fire receiver or the like, thereby detecting the occurrence of the fire. Can be notified.

  In the smoke sensor 1 of the first embodiment, the light of the surface-mounted chip type light emitting element 4 is directed to the smoke sensing area W at an acute angle with respect to the mounting surface without using an expensive prism lens or mirror surface treatment. It is possible to irradiate and detect the scattered light obtained in the smoke sensing area W by receiving it on the surface-mounted light receiving element 5.

  FIG. 4 is a vertical cross-sectional view of the smoke detector S1 according to the second embodiment of the present invention. Similar to FIGS. 1 and 3, FIG. 4 is shown in the vertical direction with the smoke detector installed on the ceiling. The smoke detector S1 is mounted in the housing 2 in the same manner as the smoke detector S of the first embodiment. FIG. 5 is a sectional view taken along line BB shown in FIG. 4, and the circuit board 10 is not shown. Hereinafter, the same parts as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

  The smoke detector S1 includes a circuit board 10, a cylindrical optical stand 11 provided on the lower side of the circuit board 10, a light guide block 12 inserted into an insertion section 111 of the optical stand 11, and an optical stand cover 8. It consists of The light emitting element 4 and the light receiving element 5 are surface-mounted on the circuit board 10, and the light guide block 7 includes an irradiation light guide path 71 and a light reception light guide path 72. In the configuration of the smoke detector S1, the circuit board 10 is mounted with the light emitting element 4, the light receiving element 5, and other circuits as in the first embodiment.

  The optical bench 11 is a structure including a smoke sensing area W1, and has an insertion portion 111 for inserting the light guide block 12 in an upper portion and a smoke detection chamber having a lower surface communicating with the insertion portion 111 in a lower portion. 112 is provided. The smoke detection chamber 112 includes a smoke sensing area W1. The insertion portion 111 is arranged so that the light guide block 12 is below the light emitting element 4 and the light receiving element 5. The side surface 112a is provided with a hole 112b communicating with the irradiation light guide path 121. Further, a hole 112c communicating with the light receiving light guide path 122 is provided on the upper surface of the smoke detection chamber 112. An opening 123 of the light guide block 12 is arranged above the smoke detection chamber 112, and the hole 112c communicates with the opening 123. The opening 123 has a slope, and a line perpendicular to the slope faces the center of the smoke detection chamber 112. A plurality of substantially J-shaped wall bodies 113 are provided on the peripheral edge of the lower surface of the optical bench 11 so as to form a labyrinth structure, as in the optical bench 6. Then, the open portion at the lower end of the wall body 113 is covered with the optical bench cover 8 to form the dark room 114. The optical table 11 is made of a black material that is an absorption color that absorbs the light emitted by the light emitting element 4. Therefore, the light emitted by the light emitting element 4 is absorbed by the surface of the optical table 11, so that the light emitted by the light emitting element 4 is reflected by the surface of the optical table 11 and enters the light receiving light guide path 122. It is possible to prevent the light receiving element 5 from detecting light that is not scattered light. The smoke sensing area W1 refers to an area in which the smoke flowing into the smoke detection chamber 112 from the outside through the smoke inlet 23 is irradiated with light from the light emitting element 4 to obtain scattered light. In the present embodiment, smoke detection is performed. It refers to a region in the chamber 112 where an optical axis L6 and an optical axis L7, which will be described later, intersect.

  The light guide block 12 has an irradiation light guide path 121 and a light reception light guide path 122 provided therein. Further, the outer shape of the light guide block 12 is a shape in which a rectangular parallelepiped projection 124 is projected on one side of the lower surface of the rectangular parallelepiped. The irradiation light guide path 121 is a space that communicates from the position of the light emitting element 4 to the side surface of the protrusion 124 on the light reception light guide path 122 side. The light receiving light guide path 122 is a space that communicates from the position of the light receiving element 5 to the opening 123 provided on the lower surface of the light guide block 12. When the light guide block 12 is inserted into the insertion portion 111, the opening 123 is arranged above the smoke detection chamber 112, and the protrusion 124 is arranged laterally of the side surface 112a of the smoke detection chamber 112. Therefore, the smoke detection chamber 112 is covered with the material of the optical bench 11 except for the portion communicating with the opening 123. The irradiation light guide path 121 communicates with the smoke sensing area W1 of the smoke detection chamber 112 through the hole 112b provided in the optical table 11 and the light reception light guide path 122 through the hole 112c provided in the optical table 11.

  The irradiation light guide 121 is a communication hole having a substantially quadrangular cross section, and is composed of an upper part 121a, a central part 121b, and a lower part 121c. The upper part 121a and the central part 121b are holes perpendicular to the mounting surface 9, and the central part 121b has a smaller diameter than the upper part 121a. A slope 121d is provided below the central portion 121b. The lower portion 121c is provided horizontally from the slope 121d. The lower portion 121c and the sloped surface 121d are provided in the protrusion 124. The inclined surface 121d is bent in the direction of the optical axis L6 so that the optical axis L5 of the light emitted from the light emitting element 4 in the downward vertical direction with respect to the mounting surface 9 is horizontally irradiated to the smoke sensing area W1 of the smoke detection chamber 112. Let

  The light receiving light guide path 122 is composed of an upper part 122a, a central part 122b, a lower part 122c, and an inclined surface 122d. Since the light receiving light guide path 122 is a communication hole having the same shape as the light receiving light guide path 72 of the first embodiment, the description of the same parts as the light receiving light guide path 72 will be omitted. The slope 122d is the direction of the optical axis L8 that irradiates the light receiving element 5 with the obliquely upward optical axis L7 of scattered light generated by smoke with respect to the light of the light emitting element 4 in the smoke sensing region W1 perpendicular to the mounting surface 9. Bend to. Since the material of the light guide block 12 is white, which is a non-absorption color, the inner surfaces of the irradiation light guide path 121 and the light reception light guide path 122 are also white. Therefore, the inner surfaces of the irradiation light guide path 121 and the light reception light guide path 122 reflect the light emitted by the light emitting element 4 and the scattered light. Therefore, the light emitted from the light emitting element 4 which travels in the direction of the optical axis L5 is reflected in the direction of the optical axis L6 by the white slope 122d and can be applied to the smoke sensing area W1. The scattered light traveling in the direction of the optical axis L7 is reflected by the white slope 122d in the direction of the optical axis L8, reaches the light receiving element 5, and is detected. In this embodiment, the slopes 121d and 122d are at an angle of 45 ° and 70 ° with respect to the horizontal direction of the mounting surface 9, respectively. The intersection angle between the optical axis L6 and the optical axis L7 is 130 °.

Next, the operation of the smoke detector S1 mounted in the housing 2 will be described.
Similar to the first embodiment, the light emitting element 4 blinks during operation. The light emitted from the light emitting element 4 bends from the direction of the optical axis L5 on the white slope 121d and advances in the direction of the optical axis L6 to irradiate the smoke sensing area W1 in the smoke detection chamber 112 with the light. Smoke generated at the time of a fire flows from the smoke inlet 23 between the wall 113 of the smoke detector S1 and into the smoke detector 112 through the dark chamber 114. The smoke that has flowed into the smoke detection chamber 62 generates scattered light with respect to the light emitted from the light emitting element 4 in the smoke sensing area W1. Then, the scattered light is bent at the white slope 122d from the direction of the optical axis L7, travels in the direction of L8, and reaches the light receiving element 5. Then, the fire detection circuit mounted on the circuit board 10 detects the occurrence of a fire based on the output of the light receiving element 5 that has detected the scattered light, and sends a fire occurrence signal to a fire receiver or the like to notify the occurrence of the fire. can do.

  The smoke detector having the smoke detector S1 of the second embodiment irradiates the smoke sensing area W1 with the light of the surface-mounted chip type light-emitting element 4 without using an expensive prism lens or mirror surface treatment to The scattered light obtained in the sensing region W can be detected by the surface-mounted light receiving element 5. Then, scattered light in an obtuse angle from the light irradiation direction can be detected.

  As shown in the above embodiments, according to the present invention, it is possible to irradiate the light of the light emitting element to the smoke sensing area at an arbitrary angle with respect to the mounting surface without using an expensive prism lens or mirror surface treatment. In addition, the light receiving element can detect the scattered light obtained in the smoke sensing area. In addition, since the material of the optical bench is made of an absorbing color and the material of the light guide block is made of a non-reflective color, and is a separate component, it is not necessary to paint each part separately. Since the light guide block is inserted into the insertion portion of the optical stand, it is not necessary to position the light guide block, so that the assembly is simple and the smoke detector manufacturing cost can be kept low. . Further, since the entire inner surfaces of the irradiation light guide and the light reception guide are covered with a non-absorptive color, not only the light traveling straight along the optical axis but also the light traveling in the optical axis direction while being reflected in the light guiding path. It is possible to irradiate the smoke sensing region with light with an increased light intensity or to have the light receiving element receive the light. Therefore, even a light emitting element having weak emission intensity and wide directional characteristics can exhibit sufficient smoke detection performance.

  Although the light emitting element 4 and the light receiving element 5 are chip-type elements in the above-described embodiments, either one or both of them may not be chip-type elements, and the present invention is not limited to the above-described embodiments. In the second embodiment, either the light emitting element 4 or the light receiving element 5 may be installed on the table provided on the circuit board and installed at the position of the slope 121d. In that case, the optical path of light emission or light reception is lateral and reaches the smoke sensing area W1.

  Further, as another embodiment, in the above embodiment, the irradiation light guide path and the light reception light guide path are integrally provided in one light guide block, but the irradiation light guide path and the light reception light guide path are separately provided. It may be provided in the light guide block. If either the light emitting element or the light receiving element irradiates the smoke monitoring area with light without using a light guide path or receives scattered light obtained by smoke, either the irradiation light guide path or the light reception light guide path is used. Only one of them may be provided in the light guide block. In this case, the light guide block may be thinly formed around the irradiation light guide path or the light reception light guide path, and the outer shape of the light guide block may follow the shape of the irradiation light guide path or the light reception light guide path. The shape of the light guide block of the above embodiment is not limited.

  Although the light emitting element 4 is a light emitting element that emits near-infrared light in the above embodiments, it may be a light emitting element that emits visible light such as red or blue, and is not limited to the above embodiments. In the above embodiment, the angle at which the optical axis L2 and the optical axis L3 of the smoke sensing area W intersect is 70 °, and the angle at which the optical axis L6 and the optical axis L7 of the smoke sensing area W1 intersect is 130 °. However, depending on the type of light emitted from the light emitting element 4 and the type of smoke to be detected, the irradiation light guide path and the light reception light guide path may be configured such that the angle at which the smoke sensing areas W and W1 intersect is an appropriate angle. Of course, it is not limited to the configuration of the above embodiment. Further, although black is used as the absorption color in the above embodiment, any color that absorbs the light used for detection may be used, and the color of the absorption color is not limited to that in the above embodiment. Although white is used as the non-absorptive color in the above embodiment, any color that reflects light emitted from the light-receiving element or scattered light, such as gold, silver or a color close to white, may be used. The color is not limited to this embodiment. Although the light guide blocks 7 and 12 are made of a white material in the embodiment, at least the inner surface of the light guide path may be a non-absorptive color, and the inner surface may be coated with a non-absorptive material. In the above embodiment, the material of the optical benches 6 and 11 is black, and the material of the light guide blocks 7 and 12 is white. However, it suffices that at least the surface of the material of the optical benches 6 and 11 is an absorption color, and at least the surfaces of the irradiation light guide paths 71 and 121 and the light reception light guide paths 72 and 122 of the light guide blocks 7 and 12 are non-absorption colors. It is preferable that the entire surfaces of the irradiation light guide path and the light reception light guide path have a non-absorption color. If the entire surface is a non-absorptive color, then light of a different direction is also guided. Although the mounting surface is the ceiling in the embodiment, the mounting surface may be a wall, an oblique ceiling, or the like, and is not limited to the above embodiment.

1 smoke detector, 2 housing, 21 main body, 22 cover, 23 smoke inlet, 3, 10 circuit board, 4 light emitting element, 5 light receiving element, 6, 11 optical stand, 61, 111 insertion part, 62, 112 inspection Smoke chamber, 62a, 62b, 112b, 112c hole, 63 partition wall, 64, 113 wall body, 65, 114 dark room, 7, 12 light guide block, 71, 121 irradiation light guide path, 71a, 72a, 121a, 122a upper part , 71b, 72b, 121b, 122b Central part, 71c, 72c, 121c, 122c Lower part, 71d, 72d, 121d, 122d Slope, 72, 122 Light receiving light guide path, 73, 123 Opening part, 8 Optical base cover, 9 Mounting Surface, 112a side surface, W, W1 smoke sensing area, L1 to L8 optical axis, θ acute angle

Claims (4)

A circuit board on which electrical parts for realizing the function of detecting smoke are mounted,
A light emitting device which is mounted on the circuit board and emits light for sensing smoke;
A smoke sensing region that irradiates smoke from the outside with light from the light emitting element to obtain scattered light,
A light-receiving element mounted on the circuit board to receive the scattered light;
In the smoke detector consisting of
A light guide block having at least one of an irradiation light guide path that is a space that communicates the light emitting element and the smoke sensing area, or a light reception light guide path that is a space that communicates the light receiving element and the smoke sensing area. Prepare,
At least the surface of the material of the optical bench, which is the structure including the smoke sensing area, is configured with an absorbing color that absorbs the light emitted by the light emitting element, and at least the surface of the material of the light guide block is a non-absorbing color. A smoke detector characterized by being constructed.   The smoke detector according to claim 1, wherein at least one of the light emitting element and the light receiving element is a chip-type element that is surface-mounted on the circuit board.   The irradiation light guide path is provided so that light from the light emitting element irradiates the smoke sensing region from a direction that is the same as a horizontal direction with respect to a mounting surface of the smoke detector or an acute angle with respect to the horizontal direction. The smoke detector according to claim 1 or 2, characterized in that.   The smoke detector according to any one of claims 1 to 3, wherein the optical table has an insertion portion, and the light guide block is inserted into the insertion portion.

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