JP2021162937A - Sensing case and smoke sensor - Google Patents

Abstract

To provide a sensing case and a smoke sensor capable of easily suppressing an increase in stray light.SOLUTION: A sensing case 1 is used for a smoke sensor including a light-emitting element 4 and a light-receiving element 5, and includes a case main body 110 and a covering body 7. The light-emitting element 4 outputs light toward a sensing space Sp1. The light-receiving element 5 is arranged at a position where direct light from the light-emitting element 4 is not incident and scattered light by smoke in the sensing space Sp1 is incident. The case main body 110 surrounds the sensing space Sp1. The covering body 7 is liquid or gel-like. The covering body 7 covers at least a part of a surface 101 of the case main body 110.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a sensing case and a smoke detector in general, and more particularly to a sensing case used in a smoke detector including a light emitting element and a light receiving element, and a smoke detector including the sensing case.

In Patent Document 1, smoke is detected by irradiating smoke that has entered the sensing space (smoke sensitive region) with light from a light emitting element (light emitting element) and receiving the scattered light from the smoke with a light receiving element. Smoke detectors are listed.

The smoke detector described in Patent Document 1 enables smoke to flow into a sensing area surrounded by a plurality of labyrinth walls from a smoke inflow path formed by gaps between the labyrinth walls. In addition, the labyrinth wall has an external light blocking action that prevents external light from entering through the smoke inflow path so that the smoke sensing function is not unstable due to external light.

Japanese Unexamined Patent Publication No. 2010-40009

In the configuration described in Patent Document 1, for example, when dust enters the sensing space, a part of the light output from the light emitting element may be reflected by the dust toward the light receiving element. As a result, not only scattered light from smoke in the sensing space but also reflected light from dust may be incident on the light receiving element, which may increase stray light.

The present disclosure has been made in view of the above reasons, and an object of the present disclosure is to provide a sensing case and a smoke detector that can easily suppress an increase in stray light.

The sensing case according to one aspect of the present disclosure is used for a smoke detector including a light emitting element and a light receiving element, and includes a case body and a covering body. The light emitting element outputs light toward the sensing space. The light receiving element is arranged at a position where the direct light from the light emitting element is not incident and the scattered light by smoke in the sensing space is incident. The case body surrounds the sensing space. The coating is liquid or gel-like. The covering covers at least a part of the surface of the case body.

The smoke detector according to one aspect of the present disclosure includes the sensing case, the light emitting element, and the light receiving element.

According to the present disclosure, there is an advantage that a sensing case and a smoke detector that can easily suppress an increase in stray light can be provided.

FIG. 1A shows a main part of the detection block of the smoke detector according to the first embodiment, and is a schematic end view corresponding to the cross section of A1-A1 in FIG. FIG. 1B is an enlarged schematic view of region Z1 of FIG. 1A. FIG. 1C is an enlarged schematic view of region Z2 of FIG. 1A. FIG. 2A is an external perspective view of the smoke detector as seen from diagonally below. FIG. 2B is an external perspective view of the smoke detector as seen from diagonally above. FIG. 3 is an exploded perspective view of the smoke detector as seen from diagonally above. FIG. 4 is a partially broken perspective view of the smoke detector of the above. FIG. 5 is an exploded perspective view of the sensing block in the smoke detector of the same. FIG. 6 is a plan view of the detection block with the second case of the smoke detector of the same as above removed. FIG. 7 shows a part of the surface of a sample made of the same material as the case body of the smoke detector as above, in order to compare the state of the covered area and the uncovered area. It is a magnified micrograph. FIG. 8 is a graph comparing the amount of increase in stray light by the dust test for a plurality of samples. FIG. 9 is a partially cutaway perspective view of the sensing block according to the second embodiment. FIG. 10A is a plan view of the sensing block according to the third embodiment with the second case removed. FIG. 10B is a plan view of the sensing block according to the modified example of the third embodiment with the second case removed.

(Embodiment 1)
(1) Outline The sensing case 1 (see FIG. 1A) according to the present embodiment is used for the smoke detector 10 (see FIG. 2A). That is, the sensing case 1 is a case for the smoke detector 10.

The smoke detector 10 according to the present embodiment is a disaster prevention device that issues a report when it detects smoke generated by a fire or the like. That is, when smoke is generated at the time of a disaster such as a fire, the smoke detector detects the smoke and, for example, issues an alarm by outputting an alarm sound or interlocking with other devices by a communication function. The "disaster prevention device" referred to in the present disclosure is, for example, a device installed in a facility for the purpose of preventing a disaster such as a fire, preventing the spread of damage due to a disaster, or recovering from a disaster.

As shown in FIGS. 2A and 2B, the smoke detector 10 includes a housing 2, and various parts are housed in the housing 2. The smoke detector 10 is installed and used in the facility. In this embodiment, the case where the smoke detector 10 is used in a non-residential facility such as a hotel, an office building, a school, a welfare facility, a commercial facility, a theme park, a hospital or a factory will be illustrated. Not limited to this, the smoke detector 10 may be used in a facility such as an apartment house or a detached house. The smoke detector 10 is installed in a facility in a state of being attached to a ceiling, a wall, or the like, for example, in a living room, a corridor, a staircase, or the like of the facility.

As shown in FIG. 3, the smoke detector 10 according to the present embodiment includes a sensing block 100 housed in the housing 2. As shown in FIG. 1A, the sensing block 100 includes a sensing case 1, a light emitting element 4, and a light receiving element 5. The sensing case 1 forms a sensing space Sp1 inside the sensing case 1. That is, the internal space of the sensing case 1 becomes the sensing space Sp1. The light emitting element 4 outputs light toward the sensing space Sp1. The light receiving element 5 is arranged at a position where the direct light from the light emitting element 4 is not incident and the scattered light by smoke in the sensing space Sp1 is incident. Therefore, the smoke detector 10 can detect the smoke existing in the sensing space Sp1 depending on the light receiving state of the light receiving element 5.

The sensing case 1 according to the present embodiment is used for the smoke detector 10 including the light emitting element 4 and the light receiving element 5 as described above. That is, the sensing case 1 is located at a position where the light emitting element 4 that outputs light toward the sensing space Sp1 and the light scattered from the smoke in the sensing space Sp1 are incident without direct light from the light emitting element 4. It is used in a smoke detector 10 including a light receiving element 5 to be arranged. As shown in FIGS. 1A to 1C, the sensing case 1 includes a case main body 110 and a covering body 7. The case body 110 surrounds the sensing space Sp1. The covering body 7 is in a liquid or gel state. The covering body 7 covers at least a part of the surface 101 of the case body 110.

According to this configuration, at least a part of the surface 101 of the case body 110 surrounding the sensing space Sp1 is covered with the liquid or gel-like covering body 7. Therefore, for example, when the dust X1 (see FIG. 1B) enters or is about to enter the sensing space Sp1, the dust X1 is easily captured by the covering body 7. When the dust X1 is captured by the covering body 7, it is possible to reduce the possibility that a part of the light output from the light emitting element 4 is diffusely reflected by the dust X1 and incident on the light receiving element 5. As a result, there is an advantage that the increase of stray light can be easily suppressed.

Further, the sensing case 1 according to the present embodiment is used for a smoke detector 10 including a light emitting element 4 and a light receiving element 5. That is, the smoke detector 10 according to the present embodiment includes a sensing case 1, a light emitting element 4, and a light receiving element 5 according to the present embodiment. Therefore, in the smoke detector 10 according to the present embodiment, it becomes easy to suppress an increase in stray light, and it is possible to improve the detection accuracy of the smoke detector 10.

(2) Details Hereinafter, the configurations of the sensing case 1 and the smoke detector 10 according to the present embodiment will be described in detail.

(2.1) Premise In the present embodiment, the smoke detector 10 will be described as being mounted on the ceiling of the facility as an example. Hereinafter, the direction perpendicular to (orthogonal) to the horizontal plane in the state where the smoke detector 10 is mounted on the ceiling will be referred to as “vertical direction”, and the lower direction in the vertical direction will be referred to as “downward”. The arrows indicating the "vertical direction" in the drawings are shown for the sake of explanation only, and are not accompanied by substance. However, these directions do not mean to limit the usage direction (mounting direction) of the smoke detector 10. For example, the "downward" defined here may be the front (horizontal direction) in the actual installation state of the smoke detector 10.

Further, the "smoke detector" referred to in the present disclosure may have a function of detecting smoke, and may further have a function of detecting an element other than smoke, for example. As an example, the smoke detector 10 may be configured to detect at least one of heat and carbon monoxide (CO) in addition to smoke. That is, the smoke detector 10 may be a multi-sensor that complexly senses smoke and elements other than smoke (heat, etc.). The sensing case 1 according to the present embodiment is also applicable to such a multi-sensor.

The "gel-like" in the present disclosure means a state having an intermediate property between a liquid and a solid, and includes a colloidal state consisting of two phases, a liquid phase and a solid phase. For example, a state called gel or sol, such as an emulsion in which the dispersion medium is a liquid phase and the dispersoid is a liquid phase, and a suspension in which the dispersoid is a solid phase, is present. Included in "gel". In addition, a state in which the dispersion medium is a solid phase and the dispersoid is a liquid phase is also included in the “gel state”. That is, the liquid or gel-like covering body 7 is an object having a constant volume if the temperature and pressure are constant, and having the property of a fluid having no fixed shape like a liquid. In other words, the covering body 7 is a fluid (fluid) other than a gas. The term "fluid" as used herein includes both Newtonian fluids and non-Newtonian fluids.

Further, the "dust" referred to in the present disclosure is a minute foreign substance (object) that does not originally exist in the sensing space Sp1 such as "dust", "dust" and "dust" that enters the sensing space Sp1 from outside the sensing space Sp1. be. Examples of "dust" include fiber waste, dust, pollen, fly ash, plant spores, mites (including mortality and dung), metal dust, microorganisms (molds, fungi) and pet hair, and PM2.5, etc. There are particulate matter (Particulate Matter) and the like. In particular, if the size of the long side is 0.1 [μm] or more and 1000 [μm] or less, and the dust X1 has the property of floating in the atmosphere, it enters the sensing space Sp1 and emits light element 4. There is a possibility that a part of the light output from is diffusely reflected. In this embodiment, as an example, it is assumed that the fly ash having a particle size of 1 [μm] or more and 100 [μm] or less is dust X1.

Further, in each of the drawings described below, the configurations of the sensing case 1 and the smoke detector 10 are schematically shown, and various dimensional relationships and the like in the drawings may differ from the actual ones.

(2.2) Overall Configuration Next, the overall configuration of the smoke detector 10 according to the present embodiment will be described with reference to FIGS. 2A to 4.

As described above, the smoke detector 10 includes a housing 2 and a sensing block 100. Further, in the present embodiment, as shown in FIG. 3, the smoke detector 10 further includes a circuit block 20, a sound output unit 61, and a battery 62. The battery 62 is not essential to be included in the component of the smoke detector 10, and the battery 62 may not be included in the component of the smoke detector 10.

The housing 2 has a disk shape that is circular in a plan view. The housing 2 is a molded product made of synthetic resin. The housing 2 has a first cover 21 and a second cover 22. The first cover 21 is combined with respect to the second cover 22 so as to cover the lower surface of the second cover 22. The second cover 22 is fixed to the construction surface (ceiling surface in this embodiment). However, strictly speaking, the second cover 22 is not directly fixed to the construction surface, but is indirectly fixed to the construction surface by being fixed to the mounting base fixed to the construction surface. NS.

Here, the first cover 21 and the second cover 22 are both formed in a disk shape, and have the same outer peripheral shape in a plan view. Therefore, by combining the first cover 21 and the second cover 22, one disk-shaped housing 2 is formed. The first cover 21 is connected to the second cover 22 by a plurality of (three) screws 63. A sensing block 100, a circuit block 20, and a sound output unit 61 are housed between the first cover 21 and the second cover 22 in a state where the first cover 21 and the second cover 22 are coupled to each other.

The first cover 21 has a circuit area 213 for arranging the circuit block 20 and a first acoustic area 214 for arranging the sound output unit 61 on the upper surface. The first cover 21 further has a push button 215 arranged within the circuit area 213. The push button 215 is movably configured by a hinge structure, and can be pushed inside the housing 2, that is, upward. By pushing the push button 215, the switch included in the circuit block 20 arranged in the circuit area 213 is operated. A sound hole 217 (see FIG. 2A) that penetrates the first cover 21 in the thickness direction (vertical direction) is formed in the first acoustic region 214.

The second cover 22 has a storage area 223 (see FIG. 4) for arranging the sensing block 100 on the lower surface. The second cover 22 further has a battery area 225 for accommodating the battery 62 on the upper surface.

Further, the second cover 22 further has a plurality of spacers 226 protruding downward from the lower surface. The plurality of spacers 226 secure a predetermined gap between the first cover 21 and the second cover 22 by bringing their respective tip portions (lower end portions) into contact with the upper surface of the first cover 21. Specifically, in a state where the first cover 21 and the second cover 22 are coupled to each other, the inside of the housing 2 is between the first cover 21 and the second cover 22 on the outer peripheral surface of the housing 2. A gap is formed as an opening 23 that connects the space to the outside of the housing 2. As a result, smoke can flow into the internal space of the housing 2, that is, the space between the first cover 21 and the second cover 22 through the opening 23.

Here, as described above, the sensing block 100 includes a sensing case 1, a light emitting element 4, and a light receiving element 5. The light emitting element 4 outputs light toward the sensing space Sp1 formed in the sensing case 1. The light receiving element 5 is arranged at a position where the direct light from the light emitting element 4 is not incident and the scattered light by smoke in the sensing space Sp1 is incident. Therefore, the sensing block 100 can sense the smoke existing in the sensing space Sp1 in the sensing case 1 depending on the light receiving state of the light receiving element 5.

As shown in FIG. 4, the sensing block 100 is housed in the internal space of the housing 2, that is, in the space between the first cover 21 and the second cover 22, together with the circuit block 20 and the like. In the present embodiment, as an example, the sensing block 100 is arranged above the circuit block 20 in the internal space of the housing 2. Details will be described in the column of "(2.3) Configuration of sensing block", but a part of the sensing case 1 is a wall structure 3 (see FIG. 5) that takes in smoke from the outside of the sensing space Sp1 into the sensing space Sp1. Function.

Since the internal space of the housing 2 is connected to the outside of the housing 2 through the opening 23 as described above, smoke can flow into the internal space of the housing 2 through the opening 23. In FIG. 4, a part of the smoke entry path is schematically indicated by a dotted arrow. Since the sensing block 100 has a wall structure 3 that takes in smoke from the outside of the sensing space Sp1 into the sensing space Sp1, the smoke that has flowed into the internal space of the housing 2 can further flow into the sensing space Sp1. This makes it possible for the sensing block 100 to detect smoke.

The circuit block 20 includes a printed wiring board 201 and a plurality of electronic components including a switch. The plurality of electronic components are mounted on the printed wiring board 201. The light emitting element 4 and the light receiving element 5 of the sensing block 100 are electrically connected to the conductor portion of the printed wiring board 201. Further, the sound output unit 61 and the battery 62 are further electrically connected to the conductor portion of the printed wiring board 201. In the present embodiment, the printed wiring board 201 is arranged below the sensing block 100, that is, between the sensing block 100 and the first cover 21. The sensing block 100 is mounted on one surface (upper surface) of the printed wiring board 201 in the plate thickness direction.

Here, the circuit block 20 includes a control circuit composed of a plurality of electronic components. The control circuit is a circuit that controls the light emitting element 4, the light receiving element 5, the sound output unit 61, and the like, drives at least the light emitting element 4, and executes signal processing on the output signal of the light receiving element 5. In signal processing, the circuit block 20 determines the presence or absence of smoke in the sensing space Sp1 by comparing the light receiving amount (magnitude of the output signal) of the light receiving element 5 with the threshold value. The amount of light received by the light receiving element 5 varies depending on, for example, the concentration of smoke in the sensing space Sp1 and the type of smoke (white smoke, black smoke, etc.). Therefore, the circuit block 20 determines that there is "smoke" when smoke having a concentration equal to or higher than a certain level is present in the sensing space Sp1 by comparison with the threshold value. When the circuit block 20 senses the presence of smoke, it outputs an electric signal for driving the sound output unit 61 to the sound output unit 61.

The sound output unit 61 receives an electric signal from the circuit block 20 and outputs a sound (sound wave). The sound output unit 61 is realized by a speaker, a buzzer, or the like that converts an electric signal into sound. The sound output unit 61 has a disk shape that is circular in a plan view.

The battery 62 is housed in the battery area 225 above the second cover 22. The battery 62 may be either a primary battery or a secondary battery.

The smoke detector 10 according to the present embodiment configured as described above is included in, for example, a component of an automatic fire alarm system. In the automatic fire alarm system, in addition to the smoke detector 10, for example, a receiver that receives a warning signal (fire signal) from the smoke detector 10, and a push button for operating a push button when a person discovers a fire. It is equipped with a transmitter, etc. In the automatic fire alarm system, for example, when the smoke detector 10 detects the occurrence of a fire (smoke caused by), the smoke detector 10 transmits a warning signal (fire signal) to notify the receiver of the occurrence of a fire. Will be done.

(2.3) Configuration of Sensing Block Next, a more detailed configuration of the sensing block 100 in the smoke detector 10 according to the present embodiment will be described with reference to FIGS. 1A, 5 and 6.

As described above, the sensing block 100 includes a sensing case 1, a light emitting element 4, and a light receiving element 5, and a part of the sensing case 1 functions as a wall structure 3. A sensing space Sp1 for sensing smoke is formed inside the sensing case 1. Further, as shown in FIGS. 5 and 6, the sensing case 1 according to the present embodiment has a light emitting element holder 8 for holding the light emitting element 4. Further, the sensing case 1 has a light receiving element holder 9 that holds the light receiving element 5.

In the present embodiment, the sensing case 1 includes a case main body 110 and a covering body 7. The covering body 7 is a liquid or gel-like member that covers at least a part of the surface 101 of the case main body 110, and maintains its shape by being fixed to the case main body 110 like a coating. Therefore, as the sensing case 1, the only member that maintains its shape by itself is the case body 110, and the case body 110 is synonymous with the sensing case 1 from a macroscopic point of view. In FIGS. 1A and 5 in which the sensing case 1 is represented macroscopically, the cover 7 is not shown. The covering body 7 will be described in detail in the column of “(2.4) Configuration of sensing case”.

The case body 110 has a disk shape that is circular in a plan view. The case body 110 is a molded product made of synthetic resin. Here, the case body 110 has at least a light-shielding property. In this embodiment, a part of the sensing case 1 functions as the wall structure 3. The wall structure 3 has a function of taking smoke into the sensing space Sp1 from the outside of the sensing space Sp1 while suppressing light from entering the sensing space Sp1 from the outside of the sensing space Sp1. The sensing block 100 senses smoke existing in the sensing space Sp1 in the sensing case 1.

In the present embodiment, as shown in FIG. 5, the case body 110 of the sensing case 1 has a first case 11 and a second case 12. The second case 12 is combined with respect to the first case 11 so as to cover the upper surface of the first case 11. The first case 11 is fixed to the printed wiring board 201 (see FIG. 3). The first case 11 has a pair of claws 111 for fixing the first case 11 to the printed wiring board 201. The pair of claws 111 project downward from the outer peripheral portion of the lower surface of the first case 11, and are hooked on the peripheral edge of the hole of the printed wiring board 201 to fix the first case 11 to the printed wiring board 201. In other words, the first case 11 is mechanically coupled to the printed wiring board 201 by a snap-fit method.

Here, both the first case 11 and the second case 12 are formed in a circular shape in a plan view, and the outer peripheral shapes in a plan view are substantially the same. Therefore, by combining the first case 11 and the second case 12, one disk-shaped sensing case 1 is formed. The first case 11 has a pair of claws 112 for connecting the first case 11 and the second case 12. The pair of claws 112 project upward from the outer peripheral portion of the upper surface of the first case 11, and are hooked on the outer peripheral surface of the second case 12 to connect the first case 11 and the second case 12. In other words, the first case 11 and the second case 12 are mechanically coupled by a snap-fit method. A sensing space Sp1 is formed between the first case 11 and the second case 12 in a state where the first case 11 and the second case 12 are coupled to each other.

The first case 11 has a circular bottom plate 13 and a wall structure 3 that projects upward from the outer peripheral portion of the (first) inner bottom surface 131 that is the upper surface of the bottom plate 13. The inner bottom surface 131 of the bottom plate 13 constitutes the bottom surface (lower surface) of the sensing space Sp1. Further, the first case 11 further has a light emitting element holder 8 and a light receiving element holder 9. Further, as shown in FIG. 6, the first case 11 further has a light-shielding wall 14, a light-shielding rib 15, and an auxiliary light-shielding wall 16. Each of the light emitting element holder 8, the light receiving element holder 9, the light shielding wall 14, the light shielding rib 15, and the auxiliary light shielding wall 16 projects upward from the inner bottom surface 131 of the bottom plate 13. Here, the amount of protrusion of the light emitting element holder 8, the light receiving element holder 9, the light shielding wall 14, and the auxiliary light shielding wall 16 from the inner bottom surface 131 of the bottom plate 13 is abbreviated as the amount of protrusion of the wall structure 3 from the inner bottom surface 131 of the bottom plate 13. It is the same.

The second case 12 has a circular upper plate 121 and a peripheral wall 122 projecting downward from the outer peripheral portion of the (second) inner bottom surface 125 (see FIG. 1A) which is the lower surface of the upper plate 121. .. The inner diameter of the peripheral wall 122 is larger than the outer diameter of the wall structure 3. Further, the amount of protrusion of the peripheral wall 122 from the inner bottom surface 125 of the upper plate 121 is substantially the same as the amount of protrusion of the wall structure 3 from the inner bottom surface 131 of the bottom plate 13. Therefore, in a state where the first case 11 and the second case 12 are connected to each other, the tip surface (lower end surface) of the peripheral wall 122 comes into contact with the inner bottom surface 131 of the bottom plate 13, and the tip surface (upper end surface) of the wall structure 3 Contact the inner bottom surface 125 of the upper plate 121. In this state, the wall structure 3 fits in the space surrounded by the peripheral wall 122.

The peripheral wall 122 is formed with a plurality of window holes 123 that penetrate the peripheral wall 122 in the plate thickness direction of the peripheral wall 122. The plurality of window holes 123 are arranged along the circumferential direction of the inner bottom surface 125 of the upper plate 121. As a result, the wall structure 3 is exposed to the outside of the sensing case 1 through the plurality of window holes 123 in a state where the first case 11 and the second case 12 are connected to each other. Here, an insect repellent net may be attached to the peripheral wall 122 so as to cover the plurality of window holes 123. The insect repellent net reduces the entry of foreign matter such as insects from the plurality of window holes 123 into the sensing space Sp1 in the sensing case 1.

Further, the second case 12 has a light-shielding rib 124 as a "second light-shielding rib" at a position facing the light-shielding rib 15 as the "first light-shielding rib" on the inner bottom surface 125 of the upper plate 121 (see FIG. 1A). Further has.

As shown in FIG. 6, the wall structure 3 surrounds the sensing space Sp1 when viewed from one direction (upper side) orthogonal to the inner bottom surface 131 (one plane) of the bottom plate 13. FIG. 6 is a plan view of the sensing block 100 in a state where the second case 12 is removed, that is, the second case 12 is omitted. In the present embodiment, a circular sensing space Sp1 is formed on the inner bottom surface 131 of the bottom plate 13 in a plan view. The wall structure 3 is formed in an annular shape so as to surround the sensing space Sp1 over the entire circumference in a plan view. In other words, an annular wall structure 3 is formed on the outer peripheral portion of the inner bottom surface 131 of the bottom plate 13 along the outer peripheral edge of the inner bottom surface 131. In a state where the first case 11 and the second case 12 are connected to each other, the space between the bottom plate 13 and the top plate 121 (see FIG. 1A) and surrounded by the wall structure 3 is the sensing space. It becomes Sp1. That is, the sensing space Sp1 and the space around the sensing space Sp1 are separated by the wall structure 3.

Here, the wall structure 3 has an inner side surface 31 facing the sensing space Sp1 side and an outer surface 32 facing the opposite side of the sensing space Sp1 on both sides of the wall structure 3 in the thickness direction. The wall structure 3 allows smoke to pass through and suppresses the transmission of light in the thickness direction. That is, the wall structure 3 is a structure having a predetermined thickness in a plan view, and has an inner side surface 31 and an outer side surface 32 on both sides in the thickness direction. In the present embodiment, the wall structure 3 is in the radial direction of the inner bottom surface 131 of the bottom plate 13, that is, the direction along the inner bottom surface 131 (one plane) of the bottom plate 13 from the periphery of the sensing space Sp1 to the center of the sensing space Sp1. The direction toward is the thickness direction of the wall structure 3. The wall structure 3 has a function of suppressing the transmission of light between the inner side surface 31 and the outer surface 32 while allowing smoke to pass through. As a result, the wall structure 3 makes it possible to take in smoke from the outside of the sensing space Sp1 into the sensing space Sp1 while suppressing light from entering the sensing space Sp1 from the outside of the sensing space Sp1. In the present embodiment, the thickness of the wall structure 3 is substantially uniform over the entire circumference, and the outer peripheral edge of the inner bottom surface 131, the inner side surface 31 and the outer surface 32 are substantially concentric in a plan view.

In order to realize the above function, such a wall structure 3 has a plurality of smoke passage holes 33 penetrating the wall structure 3 in the thickness direction, that is, penetrating between the inner side surface 31 and the outer side surface 32. ing. The plurality of smoke passage holes 33 are arranged along the circumferential direction of the wall structure 3. As a result, the wall structure 3 allows smoke to pass through each smoke passage hole 33, and enables smoke to be taken into the sensing space Sp1 from the outside of the sensing space Sp1. Here, each smoke passage hole 33 does not have a shape that penetrates straight between the inner surface 31 and the outer surface 32 in a plan view, and at least a part of the space between the inner surface 31 and the outer surface 32 is bent. The shape. That is, at least a part of each smoke passage hole 33 can be seen from the outer surface 32 side of the wall structure 3 so that the sensing space Sp1 surrounded by the wall structure 3 cannot be seen through each smoke passage hole 33. It has a curved or bent shape. As a result, the wall structure 3 is prevented from transmitting light through each smoke passage hole 33 through the wall structure 3, and it is possible to suppress light from entering the sensing space Sp1 from the outside of the sensing space Sp1. However, the smoke passage hole 33 does not have to be surrounded by the wall structure 3 all around, and for example, the wall structure 3 may not exist on both sides of the smoke passage hole 33 in the vertical direction. Further, the opening on the inner side surface 31 side and the opening on the outer side surface 32 side of each smoke passage hole 33 are on the radius of the sensing space Sp1 in a plan view, that is, on a straight line extending radially from the center point of the sensing space Sp1. , It doesn't have to be lined up.

Specifically, the wall structure 3 is an aggregate of a plurality of small pieces 30 arranged along the inner side surface 31. The wall structure 3 allows smoke to pass between these plurality of small pieces 30. In other words, on the outer peripheral portion of the inner bottom surface 131 of the bottom plate 13, a plurality of small pieces 30 are arranged side by side at intervals along the outer peripheral edge of the inner bottom surface 131. Each of the plurality of small pieces 30 protrudes from the inner bottom surface 131 of the bottom plate 13 and constitutes one wall structure 3. The amount of protrusion of the plurality of small pieces 30 from the inner bottom surface 131 is substantially uniform. The wall structure 3 has smoke passage holes 33 between a pair of adjacent small pieces 30 among the plurality of small pieces 30. Therefore, the small pieces 30 constituting the wall structure 3 do not exist on both sides of each smoke passage hole 33 in the vertical direction.

The inner surface 31 is a surface that passes through the inner edge of the plurality of small pieces 30 on the sensing space Sp1 side. The outer side surface 32 is a surface that passes through the outer edge of the plurality of small pieces 30 on the side opposite to the sensing space Sp1. In short, a smooth curved surface, a flat surface, or a combination of a flat surface and a curved surface connecting the inner edge of the plurality of small pieces 30 on the sensing space Sp1 side corresponds to the inner side surface 31. Similarly, a smooth curved surface, a flat surface, or a combination of a flat surface and a curved surface connecting the outer edge of the plurality of small pieces 30 opposite to the sensing space Sp1 corresponds to the outer surface 32.

As described above, each of the inner surface 31 and the outer surface 32 is not a surface having a substance but a virtual surface whose shape is defined by a plurality of small pieces 30 in the present embodiment. Therefore, in FIG. 6, the inner side surface 31 and the outer side surface 32 are represented by an imaginary line (two-dot chain line).

However, it is not essential that the position of the inner end edge of all of the plurality of small pieces 30 is completely the same as that of the inner side surface 31, and if the position of the inner end edge of the plurality of small pieces 30 is substantially the same as that of the inner side surface 31. good. Also in the example of FIG. 6, the majority of the small pieces 30 among the plurality of small pieces 30 have the position of the inner end edge on the sensing space Sp1 side completely coincident with the inner side surface 31, but the remaining small pieces 30 have the inner end edge. Although the position of is near the inner side surface 31, it does not completely match the inner side surface 31. As described above, the inner side surface 31 is defined by the position of the inner end edge of the majority of the small pieces 30 among the plurality of small pieces 30, and the inner end edge of the remaining small pieces 30 may be near the inner side surface 31.

The same applies to the outer side surface 32, and it is not essential that the position of the outer edge of all of the plurality of small pieces 30 is exactly the same as that of the outer surface 32, and the position of the outer edge of the plurality of small pieces 30 is the outer surface. It suffices if it substantially matches 32. That is, the outer surface 32 is defined by the position of the outer end edge of the majority of the small pieces 30 among the plurality of small pieces 30, and the outer end edge of the remaining small pieces 30 may be near the outer end surface 32. The “near” here is a range of about 20% of the thickness of the wall structure 3 when viewed from the inner surface 31 or the outer surface 32.

In the present embodiment, in a plan view, the outer surface 32 is substantially parallel to the outer peripheral edge of the inner bottom surface 131 of the bottom plate 13, that is, the distance from the outer peripheral edge of the inner bottom surface 131 to the outer peripheral surface 32 is uniform over the entire circumference. Further, as shown in FIG. 6, the inner side surface 31 is formed between the center point of the sensing space Sp1 and the outer surface 32 at a position closer to the outer surface 32 than the center point. In other words, in a plan view, when a virtual circle that is approximately concentric circles of the outer surface 32 and whose radius is half (1/2) of the outer surface 32 is drawn, between the virtual circle and the outer surface 32, The inner side surface 31 will be located. However, the shapes and arrangements of the inner side surface 31 and the outer side surface 32 are merely examples, and each of the inner side surface 31 and the outer side surface 32 may adopt other shapes and arrangements.

Here, each of the plurality of small pieces 30 has a bent portion between the inner edge on the sensing space Sp1 side and the outer edge on the opposite side of the sensing space Sp1 in a plan view. In the present embodiment, each of the plurality of small pieces 30 is formed in a substantially L-shape, a substantially V-shape, or a substantially Y-shape in a plan view. Due to such a shape, each smoke passage hole 33 formed by a gap formed between a pair of adjacent small pieces 30 is, as described above, at least a part between the inner surface 31 and the outer surface 32 in a plan view. It has a curved shape. As a result, the wall structure 3 realizes a function of allowing smoke to pass through and suppressing light transmission in the thickness direction.

The light emitting element 4 has a light emitting surface, and outputs light from the light emitting surface when energized. As an example in this embodiment, the light emitting element 4 is a light emitting diode (LED: Light Emitting Diode). As shown in FIG. 5, the light emitting element 4 has a main body portion 401. A pair of lead terminals 402 project from the surface of the main body 401. Here, the pair of lead terminals 402 are electrically connected to the main body 401 of the light emitting element 4. In this embodiment, the pair of lead terminals 402 project from the lower surface of the main body 401 of the light emitting element 4. In other words, the light emitting element 4 is a so-called side view type light emitting diode that outputs light to the side when the surface (lower surface) on which the lead terminal 402 projects is directed downward.

When the pair of lead terminals 402 are electrically connected to the printed wiring board 201, the light emitting element 4 receives power from the circuit block 20 and emits light. In the present embodiment, the pair of lead terminals 402 will not be included in the components of the light emitting element 4, but the pair of lead terminals 402 may be included in the components of the light emitting element 4.

Here, as shown in FIG. 6, the light emitting element 4 is arranged between the inner side surface 31 and the outer side surface 32 of the wall structure 3. In other words, the main body 401 of the light emitting element 4 is arranged so as to fit between the inner side surface 31 and the outer side surface 32 which are both end faces in the thickness direction of the wall structure 3. Further, the light emitting element 4 is arranged so that the light emitting surface faces the inner side surface 31 side, that is, the sensing space Sp1 side. As a result, the light emitting element 4 can output light from the light emitting surface toward the sensing space Sp1 without using an optical element such as a mirror.

On the other hand, the light receiving element 5 is an element that performs photoelectric conversion that converts light into an electric signal. In this embodiment, as an example, the light receiving element 5 is a photodiode (PD: Photodiode). As shown in FIG. 5, the light receiving element 5 has a main body 501, a pair of lead terminals 502, and a metal cover 503. The main body 501 is housed in the metal cover 503 so that at least the light receiving surface of the main body 501 is exposed from the hole of the metal cover 503. The pair of lead terminals 502 project from the lower surface of the main body 501. Here, the pair of lead terminals 502 are electrically connected to the main body 501 of the light receiving element 5. The light receiving element 5 is electrically connected to the circuit block 20 by electrically connecting the pair of lead terminals 502 to the printed wiring board 201.

The light receiving element 5 is arranged at a position where the direct light from the light emitting element 4 is not incident and the scattered light by smoke in the sensing space Sp1 is incident. Specifically, the light receiving element 5 is arranged so that the light receiving surface of the main body 501 faces the sensing space Sp1 side. That is, both the light emitting element 4 and the light receiving element 5 are arranged toward the sensing space Sp1.

However, as shown in FIG. 6, the light-shielding wall 14 is arranged on the straight line connecting the light-emitting element 4 and the light-receiving element 5 in a plan view. The light-shielding wall 14 has a function of blocking direct light from the light-emitting element 4 to the light-receiving element 5. In the present embodiment, the light-shielding wall 14 is formed in a shape continuous with one of the plurality of small pieces 30 constituting the wall structure 3.

Then, in a plan view, the light emitting element 4 and the light receiving element have a positional relationship in which the optical axis Ax1 of the light emitting element 4 (see FIG. 1A) and the optical axis Ax2 of the light receiving element 5 (see FIG. 1A) intersect each other. 5 is arranged. In the example of FIG. 6, the optical axis Ax1 of the light emitting element 4 and the optical axis Ax2 of the light receiving element 5 intersect at the center point of the circular sensing space Sp1 in a plan view. If the light emitting element 4 and the light receiving element 5 are in the positional relationship as described above, the direct light from the light emitting element 4 does not enter the light receiving element 5. On the other hand, when smoke flows into the sensing space Sp1, the light from the light emitting element 4 is scattered by the smoke existing at the center point of the sensing space Sp1, and at least a part of the scattered light is received by the light receiving element 5. NS.

As described above, in the state where there is no smoke in the sensing space Sp1, the light receiving element 5 does not receive the light output from the light emitting element 4, and in the state where there is smoke in the sensing space Sp1, the light receiving element 5 emits light. It receives the light (scattered light) output from the element 4 and scattered by the smoke. Therefore, the smoke detector 10 can detect the smoke existing in the sensing space Sp1 depending on the light receiving state of the light receiving element 5.

Further, in the present embodiment, the optical axis Ax1 of the light emitting element 4 and the optical axis Ax2 of the light receiving element 5 are along the inner bottom surface 131 (one plane) of the bottom plate 13 as shown in FIG. 1A. FIG. 1A is an end view of the A1-A1 line of FIG. In the example of FIG. 1A, the optical axis Ax1 of the light emitting element 4 and the optical axis Ax2 of the light receiving element 5 are both substantially parallel to the inner bottom surface 131 of the bottom plate 13. Further, the optical axis Ax1 of the light emitting element 4 and the optical axis Ax2 of the light receiving element 5 are located in the same plane. In other words, the optical axis Ax1 of the light emitting element 4 and the optical axis Ax2 of the light receiving element 5 are located at substantially the same height from the inner bottom surface 131 of the bottom plate 13.

As shown in FIG. 6, at least a part of the light emitting element holder 8 that holds the light emitting element 4 is arranged between the inner side surface 31 and the outer side surface 32. Specifically, the light emitting element holder 8 is arranged between a plurality of small pieces 30 constituting the wall structure 3 so that most of the light emitting element holder 8 fits between the inner side surface 31 and the outer surface 32. The light emitting element holder 8 has a recess in which the light emitting element 4 fits.

In the present embodiment, the light emitting element holder 8 further has a light shielding piece 802 as shown in FIG. The light-shielding piece 802 projects into the sensing space Sp1 from the surface of the light emitting element holder 8 facing the sensing space Sp1 side. Here, the light-shielding piece 802 projects from the end of the light-emitting element holder 8 on the side far from the light-shielding wall 14 in the circumferential direction of the wall structure 3. The light-shielding piece 802 has a function of blocking the light output from the light-emitting element 4 and reflected on the surface of the light-emitting element holder 8.

Further, at least a part of the light receiving element holder 9 that holds the light receiving element 5 is arranged between the inner side surface 31 and the outer side surface 32 as shown in FIG. Specifically, the light receiving element holder 9 is arranged between a plurality of small pieces 30 constituting the wall structure 3 so that most of the light receiving element holder 9 fits between the inner side surface 31 and the outer surface 32. The light receiving element holder 9 has a recess into which the light receiving element 5 fits.

Further, the light-shielding rib 15 is arranged in front of the light emitting element 4, that is, at a position facing the light emitting surface 41 of the light emitting element 4 in a plan view. As shown in FIG. 1A, a certain gap is formed between the light-shielding rib 15 and the light-shielding rib 124 provided in the second case 12. The optical axis Ax1 of the light emitting element 4 passes through the gap between the light-shielding rib 15 and the light-shielding rib 124. As a result, the light-shielding ribs 15 and 124 suppress the spread of the light output from the light-emitting element 4 in the vertical direction. As a result, the light output from the light emitting element 4 is suppressed from being reflected by the upper surface (inner bottom surface 131) of the bottom plate 13 or the lower surface (inner bottom surface 125) of the upper plate 121.

Further, the auxiliary light-shielding wall 16 is formed in a shape continuous with one small piece 30 located between the light-shielding wall 14 and the light receiving element holder 9 among the plurality of small pieces 30 constituting the wall structure 3. The auxiliary light-shielding wall 16 projects from the inner side surface 31 of the wall structure 3 into the sensing space Sp1. The auxiliary light-shielding wall 16 suppresses the generation of stray light inside the sensing space Sp1 due to the reflection of light on the inner bottom surface 131 of the bottom plate 13 or the inner bottom surface 125 of the upper plate 121, and enters the sensing space Sp1. It has a function to improve the inflow of smoke. That is, the auxiliary light-shielding wall 16 is a structure different from the small piece 30 which is a part of the wall structure 3 for suppressing the entry of light into the sensing space Sp1 from the outside of the sensing space Sp1. In FIG. 6, the boundary line between the auxiliary light-shielding wall 16 and the small piece 30 is shown by an imaginary line (two-dot chain line).

(2.4) Configuration of Sensing Case Next, a more detailed configuration of the sensing case 1 according to the present embodiment will be described with reference to FIGS. 1A to 1C and FIG.

The sensing case 1 is used in the sensing block 100 of the smoke detector 10 to form a sensing space Sp1 for sensing smoke. As shown in FIGS. 1A to 1C, the sensing case 1 includes a case main body 110 and a covering body 7. In FIG. 1A, the illustration of the covering body 7 is omitted. FIG. 1B is an enlarged schematic view of region Z1 of FIG. 1A. FIG. 1C is an enlarged schematic view of region Z2 of FIG. 1A. Further, in FIG. 1B, a schematic view in which a part of the cross section of the covering body 7 is further enlarged is shown in the balloon.

The case body 110 surrounds the sensing space Sp1. In other words, the case body 110 constitutes the outer shell of the sensing space Sp1 for sensing smoke. In the present embodiment, as described above, the case body 110 is a molded product made of synthetic resin and has a disk shape having a circular shape in a plan view. Further, in the present embodiment, the case main body 110 is composed of two members, a first case 11 and a second case 12. That is, a disk-shaped case that forms a sensing space Sp1 between the first case 11 and the second case 12 by being combined with the first case 11 so that the second case 12 covers the upper surface of the first case 11. The main body 110 is configured.

In the present embodiment, the first case 11 and the second case 12 constituting the case body 110 are made of the same material. As an example in the present embodiment, both the first case 11 and the second case 12 are made of polybutylene terephtalate (PBT) resin. For the first case 11 and the second case 12, the surface resistivity defined by JIS K 6911 is, for example, about 1.0 × 10 ¹⁶ [Ω / sq.]. That is, in the present embodiment, the surface resistivity of the case body 110 is 1.0 × 10 ¹¹ [Ω / sq.] Or more. As described above, the case body 110 having a relatively large surface resistivity is, in other words, an insulating material having a relatively low conductivity, and therefore has a property of being easily charged, that is, easily charged with static electricity. Then, when the case main body 110 is in a charged state, the case main body 110 tends to attract the dust X1 and other floating substances in the sensing space Sp1.

By the way, the sensing case 1 according to the present embodiment includes the covering body 7 as shown in FIGS. 1B and 1C. The covering body 7 is in a liquid or gel state. The covering body 7 covers at least a part of the surface 101 of the case body 110. The covering body 7 may cover the entire surface 101 of the case main body 110, but in the present embodiment, the covering body 7 covers only a part of the surface 101 of the case main body 110.

Here, the covering body 7 covers at least a part of the surface 101 of the case body 110 facing the sensing space Sp1. That is, the covering body 7 covers at least a part of the surface 101 of the case body 110 facing the sensing space Sp1. Specifically, the covering body 7 covers at least a part of at least one surface 101 of the wall structure 3 and the pair of inner bottom surfaces 131 and 125. That is, in the present embodiment, as described above, the case body 110 has a wall structure 3 and a pair of inner bottom surfaces 131 and 125. The wall structure 3 surrounds the sensing space Sp1 when viewed from one direction (vertical direction) orthogonal to one plane (the inner bottom surface 131 of the bottom plate 13), and allows smoke to pass through and suppresses light transmission. The pair of inner bottom surfaces 131 and 125 face each other in one direction (vertical direction).

In the present embodiment, as an example, of the wall structure 3 and the pair of inner bottom surfaces 131 and 125, the portion facing the sensing space Sp1 is covered with the covering body 7 over the entire area. In FIG. 6, the area of the surface 101 of the case body 110 covered with the covering body 7 is shaded (dot hatched). That is, in FIG. 6, the surface 101 of the case body 110 is covered by the covering body 7 over the entire shaded area. That is, in the present embodiment, in the first case 11, at least the inner surface 31 of the wall structure 3 (inner edge of the plurality of small pieces 30) and the inner surface of the (first) inner bottom surface 131 which is the upper surface of the bottom plate 13. The surface 101 of all the inner regions of 31 is covered with the covering body 7. Of the first case 11, the surface (lower surface) of the bottom plate 13 opposite to the inner bottom surface 131, and the portion outside the inner surface 31 of the inner bottom surface 131, that is, the side surfaces of the plurality of small pieces 30 constituting the wall structure 3. For example, the covering body 7 is not formed.

On the other hand, in the second case 12, the surface 101 is covered with the covering body 7 in all the inner regions of the peripheral wall 122 of at least the lower surface (second) inner bottom surface 125 of the upper plate 121. Of the second case 12, the covering body 7 is not formed on the surface (upper surface) of the upper plate 121 opposite to the inner bottom surface 125 and the portion outside the peripheral wall 122.

Further, in the present embodiment, the case body 110 has a light-shielding wall 14, a light-shielding rib 15, an auxiliary light-shielding wall 16, a light-emitting element holder 8, and a light-receiving element holder 9. Regarding the light-shielding wall 14, the light-shielding rib 15, the auxiliary light-shielding wall 16, the light-emitting element holder 8 and the light-receiving element holder 9, only the portion facing the sensing space Sp1, that is, the portion facing the sensing space Sp1, its surface 101 is covered. It is covered with 7.

As described above, in the present embodiment, the covering body 7 covers only a part of the surface 101 of the case body 110, not the entire surface 101. Here, the surface resistivity of the portion of the case body 110 covered by the covering body 7 is 1.0 × 10 ¹¹ [Ω / sq.] Or more. In particular, it is preferable that the surface resistivity of the first case 11 in the gravity direction (downward) of the case body 110 is 1.0 × 10 ¹¹ [Ω / sq.] Or more. However, the case body 110 covered with the covering body 7 has a surface resistivity of 1.0 × 10 ¹¹ [Ω / sq. ] That's all. Then, in such a portion having a relatively large surface resistivity, it is easy to be charged, and it is easy to attract the dust X1 and other suspended matter in the sensing space Sp1.

In the present embodiment, the covering body 7 is a liquid applied to at least a part of the surface 101 of the case body 110. As the covering body 7, various liquids satisfying desired properties are used, and in this embodiment, oil is used as an example. That is, when a liquid such as oil is applied to at least a part of the surface 101 of the case body 110, as shown in FIGS. 1B and 1C, at least a part of the surface 101 is covered with the liquid covering body 7. It will be covered. In other words, at least a part of the surface 101 is coated with the covering body 7.

Here, the covering body 7 is in the form of a film having thicknesses T1 and T2. In particular, in the present embodiment, since the covering body 7 is formed by applying oil, the covering body 7 is composed of an oil film having a certain thickness T1 and T2. That is, the covering body 7 is composed of a liquid coating layer (coating film) that covers at least a part of the surface 101 of the case body 110. In the present embodiment, the thicknesses T1 and T2 of the covering body 7 are substantially uniform over the entire area of the surface 101 where the covering body 7 is provided. Therefore, the thickness T1 of the covering body 7 covering the surface 101 on the first case 11 side, that is, the (first) inner bottom surface 131, and the covering body covering the surface 101 on the second case 12 side, that is, the (second) inner bottom surface 125. Is equal to the thickness T2 of 7.

As an example, the thickness T1 (or T2) of the covering body 7 is 3 [μm] or more and 300 [μm] or less. The thickness T1 (or T2) of the covering body 7 is more preferably 5 [μm] or more, more preferably 10 [μm] or more, more preferably 15 [μm] or more, and even more preferably 20 [μm] or more. The thickness T1 (or T2) of the covering body 7 is more preferably 200 [μm] or less, more preferably 150 [μm] or less, and more preferably 100 [μm] or more.

The liquid as the covering body 7 is not limited to the method of being applied to the surface 101 with a brush or the like, but is adhered to the surface 101 by an appropriate coating method such as spraying by spraying, dipping coating method, printing or transfer. , Consists of the covering body 7. Alternatively, the covering body 7 may be formed on the surface 101 by a method such as attaching a sheet member impregnated with the liquid to be the covering body 7 to the surface 101.

The sensing case 1 according to the present embodiment has an advantage that the increase of stray light can be easily suppressed by providing the covering body 7 as described above. That is, for example, when the dust X1 enters or is about to enter the sensing space Sp1, the dust X1 is easily captured by the covering body 7. When the dust X1 is captured by the covering body 7, it is possible to reduce the possibility that a part of the light output from the light emitting element 4 is diffusely reflected by the dust X1 and incident on the light receiving element 5.

More specifically, as shown in FIG. 1B, when the covering body 7 comes into contact with the dust X1 existing in the sensing space Sp1, it encloses at least a part of the dust X1. In short, the liquid or gel-like covering 7 captures the dust X1 by coming into contact with the dust X1 so as to wrap at least a part of the dust X1. In the example of FIG. 1B, the covering body 7 takes in the dust X1 inside so as to wrap the entire dust X1.

Further, since the covering body 7 wraps at least a part of the dust X1, the diffuse reflectance of the light from the light emitting element 4 in the dust X1 is reduced. That is, when the covering body 7 wraps at least a part of the dust X1, the surface of the dust X1 is covered with the covering body 7, that is, a coated state. As a result, diffuse reflection of light by the dust X1 is less likely to occur, and the possibility that a part of the light output from the light emitting element 4 is diffusely reflected by the dust X1 and is incident on the light receiving element 5 can be significantly reduced. ..

By the way, in the present embodiment, the covering body 7 satisfies the following characteristics. That is, in the present embodiment, a liquid (oil) satisfying the following characteristics is used as the covering body 7.

First, as a first characteristic, the surface tension of the covering body 7 is equal to or less than the surface tension of water. The "surface tension" here means the surface tension under the same temperature conditions. That is, for example, since the surface tension of water at 25 [° C.] is 72 [mN / m], the surface tension of the covering body 7 at 25 [° C.] is 72 [mN / m] or less. It is preferable that the surface tension of the covering body 7 is smaller than the surface tension of water, that is, the surface tension of the covering body 7 at 25 [° C.] is less than 72 [mN / m]. Further, the surface tension of the covering body 7 at 25 [° C.] is 60 [mN / m] or less, 50 [mN / m] or less, 40 [mN / m] or less, 30 [mN / m] or less, 20 [. It is more preferably mN / m] or less. As described above, when the surface tension of the covering body 7 is small, the contact angle of the covering body 7 with respect to the dust X1 becomes small, and the wettability of the covering body 7 with respect to the dust X1 is improved. When the wettability of the covering body 7 is improved, when the dust X1 comes into contact with the covering body 7, at least a part of the dust X1 is easily wrapped in the covering body 7, and the dust X1 is easily captured.

The second characteristic is that the saturated vapor pressure of the coating is equal to or less than the saturated vapor pressure of water. The "saturated vapor pressure" here means the saturated vapor pressure under the same temperature conditions. That is, for example, since the saturated vapor pressure of water at 25 [° C.] is 3.2 [kPa], the saturated vapor pressure of the covering body 7 at 25 [° C.] is 3.2 [kPa] or less. It is preferable that the saturated vapor pressure of the covering body 7 is smaller than the saturated vapor pressure of water, that is, the saturated vapor pressure of the covering body 7 at 25 [° C.] is less than 3.2 [kPa]. Further, the saturated vapor pressure of the covering body 7 at 25 [° C.] is 1500 [Pa] or less, 1000 [Pa] or less, 500 [Pa] or less, 100 [Pa] or less, 50 [Pa] or less, 10 [Pa] or less. ] Or less, more preferably 0.5 [Pa] or less. As described above, since the saturated vapor pressure of the covering body 7 is small, the covering body 7 is less likely to evaporate, and the thicknesses T1 and T2 of the covering body 7 are less likely to decrease due to the evaporation of the covering body 7.

As a third characteristic, the viscosity of the covering body 7 is 2000 [mPa · s] or less. The "viscosity" here means the viscosity at room temperature (25 [° C.]). That is, for example, since the viscosity of condensed milk at 25 [° C.] is 2000 [mPa · s], it can be said that the viscosity of the covering body 7 is equal to or less than the viscosity of condensed milk. It is preferable that the viscosity of the covering body 7 is smaller than the viscosity of condensed milk, that is, the viscosity of the covering body 7 at 25 [° C.] is less than 2000 [mPa · s]. Further, the viscosity of the covering body 7 at 25 [° C.] is 1500 [mPa · s] or less, 1000 [mPa · s] or less, 850 [mPa · s] or less, 600 [mPa · s] or less, 400 [mPa · s] or less. -S] It is more preferable that it is less than or equal to. As described above, since the viscosity of the covering body 7 is small, when the dust X1 comes into contact with the covering body 7, at least a part of the dust X1 is easily wrapped in the covering body 7, and the dust X1 is easily captured.

(3) Experimental Results Hereinafter, the operations of the sensing case 1 and the smoke detector 10 according to the present embodiment will be described with reference to FIGS. 7 and 8.

FIG. 7 is an enlargement of a part of the surface of a sample made of the same material as the case body 110 in order to compare the states of the region R1 covered with the covering 7 and the region R2 not covered with the covering 7. It is a micrograph taken. In FIG. 7, the alternate long and short dash line indicating each range of the region R1 and the region R2 is shown only for the sake of explanation and is not accompanied by an entity. FIG. 7 shows a state of the sample after a plate-shaped sample made of the same material as the case body 110 is exposed to dust X1 and subjected to a dust test for evaluating dust resistance. Here, 5 or 10 types of fly ash defined in "JIS Z8901" are used as the dust X1 by an appropriate test method such as an air flow test or a floating test. Further, the material of the sample is a polybutylene terephtalate (PBT) resin.

As is clear from FIG. 7, in the region R2 of the surface 101 of the case body 110 that is not covered by the covering body 7, the dust X1 adheres to the surface 101 in a state where the entire surface 101 is exposed. Therefore, the dust X1 is exposed in the sensing space Sp1, and the light output from the light emitting element 4 may be diffusely reflected by the dust X1 and incident on the light receiving element 5.

On the other hand, in the region R1 of the surface 101 of the case body 110 covered with the covering body 7, at least a part of the dust X1 is wrapped in the covering body 7, as is clear from FIG. In the example of FIG. 7, the dust X1 is entirely wrapped in the covering body 7. When the dust X1 is wrapped in the covering body 7, the light output from the light emitting element 4 is unlikely to reach the dust X1, and as a result, the diffuse reflection of the light by the dust X1 is unlikely to occur. Alternatively, even if the light reaches the dust X1, the light diffusely reflected by the dust X1 does not easily leak to the outside of the covering body 7 and does not easily reach the light receiving element 5.

FIG. 8 is a graph comparing the amount of increase in stray light [% / m] by the dust test (using fly ash as dust X1) as described above for a plurality of samples. In FIG. 8, the samples of “S3” and “S4” are the sensing cases 1 according to the present embodiment provided with the covering body 7, and the samples of “S1” and “S2” are provided with the covering body 7. This is a sensing case according to a comparative example. In all of the "S2", "S3" and "S4" samples, the material of the case body 110 is polybutylene terephthalate (PBT) resin. The "S1" sample is made of a resin that is less likely to be charged than the polybutylene terephthalate (PBT) resin, that is, the surface resistivity of the case body 110 is lower than that of the "S2" sample. Further, the sample of "S4" has a larger thickness of the covering body 7 than the sample of "S3".

As is clear from FIG. 8, in the sensing case 1 (samples “S3” and “S4”) according to the present embodiment, dust is compared with any of the comparative examples (samples “S1” and “S2”). The increase in stray light after the test is significantly reduced. That is, according to the configuration in which the surface 101 of the case body 110 is covered with the covering body 7 as in the sensing case 1 according to the present embodiment, the stray light due to the dust X1 is compared with the configuration in which the covering body 7 is not provided. It is possible to significantly reduce the amount of increase in. Further, as is clear from the comparison result between the sample "S3" and the sample "S4", if the thickness of the covering body 7 is increased, the amount of increase in stray light due to the dust X1 can be further reduced.

7 and 8 show only one experimental result for explaining the operation of the sensing case 1 and the smoke detector 10 according to the present embodiment, and show only one experimental result, and the sensing case 1 and the smoke sensing according to the present embodiment. It is not intended to limit the embodiment of the vessel 10.

(4) Modified Example The first embodiment is only one of the various embodiments of the present disclosure. The first embodiment can be changed in various ways depending on the design and the like as long as the object of the present disclosure can be achieved. Each figure described in the present disclosure is a schematic view, and the ratio of the size and the thickness of each component in each figure does not necessarily reflect the actual dimensional ratio.

Hereinafter, modifications of the first embodiment will be listed. The modifications described below can be applied in combination as appropriate.

In the first embodiment, the wall structure 3 is composed of an aggregate of a plurality of small pieces 30, but the structure is not limited to this, and the wall structure 3 may be an integral "wall" continuous in the circumferential direction. Even in this case, the wall structure 3 has a plurality of smoke passage holes 33 penetrating the wall structure 3 in the thickness direction, so that it is possible to realize a function of allowing smoke to pass through the wall structure 3 and suppressing light transmission in the thickness direction. be.

Further, in the first embodiment, the configuration in which the sensing block 100 is housed in the internal space of the housing 2 is shown, but the present invention is not limited to this configuration, and for example, at least a part of the sensing block 100 protrudes from the housing 2. It may be. Furthermore, the housing 2 is not an essential configuration for the smoke detector 10, and can be omitted as appropriate.

Further, in the first embodiment, the case where both the sensing case 1 and the sensing space Sp1 have a circular shape in a plan view has been described, but the present invention is not limited to this configuration, and the sensing case 1 or the sensing space Sp1 is, for example, in a plan view. It may have an elliptical shape, a polygonal shape, or the like. In this case, the wall structure 3 also has an elliptical shape, a polygonal shape, or the like in a plan view.

Further, in the first embodiment, a part of the light emitting element holder 8 is arranged so as to protrude from the inner side surface 31 of the wall structure 3 into the sensing space Sp1, but the whole of the light emitting element holder 8 is not limited to this configuration. May fit between the inner surface 31 and the outer surface 32. Similarly, the light receiving element holder 9 may be accommodated between the inner side surface 31 and the outer side surface 32.

Further, in the first embodiment, the plurality of small pieces 30 are integrally formed with the bottom plate 13 so as to protrude from the inner bottom surface 131 of the bottom plate 13, but the present invention is not limited to this configuration, and the plurality of small pieces 30 are separate from the bottom plate 13. It may be a body. For example, a plurality of small pieces 30 may be fixed to the bottom plate 13 by adhesion, fitting, or the like. In this case, the plurality of small pieces 30 will be present separately, but even in this case, the plurality of small pieces 30 form one wall structure 3.

Further, the light emitting element 4 is not limited to the light emitting diode, and may be, for example, an organic EL (Electro-Luminescence) element, a laser diode (LD), or the like. The light receiving element 5 is not limited to the photodiode, and may be, for example, a phototransistor or the like.

Further, in the first embodiment, the case body 110 is made of a material having a relatively high surface resistivity (that is, a relatively low conductivity), such as polybutylene terephthalate (PBT) resin, but is not limited to this example. That is, at least a part of the case body 110 may have a surface resistivity of ^{less than 1.0 × 10 11} [Ω / sq.]. As described above, when a material having a relatively low surface resistivity (that is, a relatively high conductivity) is applied to at least a part of the case body 110, the case body 110 is less likely to be charged, and dust X1 and other materials are not easily charged. It becomes difficult to attract floating objects in the sensing space Sp1.

Further, in the first embodiment, the first case 11 and the second case 12 are made of the same material (polybutylene terephthalate resin), but the present invention is not limited to this example. For example, the first case 11 and the second case 12 may be made of different materials. In this case, even if a material is applied such that one of the first case 11 and the second case 12 has a relatively low surface resistivity and is easily charged, and the other has a relatively high surface resistivity and is difficult to be charged. good. In this case, the surface resistivity of the first case 11 in the direction of gravity (downward) of the case body 110 may be lower than that of the second case 12, and conversely, as compared with the second case 12. It may be expensive.

Further, in the first embodiment, the covering body 7 is provided in both the first case 11 and the second case 12, but the present invention is not limited to this example. That is, since the covering body 7 only needs to cover at least a part of the surface 101 of the case main body 110, the covering body 7 may be provided only on one of the first case 11 and the second case 12. In this case, it is preferable that the covering body 7 is provided on the surface 101 of the first case 11 which is in the direction of gravity (downward) when viewed from the sensing space Sp1 of the surface 101 of the case body 110. In particular, it is preferable that the covering body 7 covers the inner bottom surface 131 forming the bottom surface (lower surface) of the sensing space Sp1 even in the first case 11. As a result, the surface 101 in the direction of gravity when viewed from the sensing space Sp1 is covered with the covering body 7, so that the dust X1 accumulated on the bottom surface (lower surface) of the sensing space Sp1 can be easily captured by the covering body 7 and covered. The effect of body 7 becomes remarkable.

Further, the sensing block 100 is not limited to the configuration arranged above the circuit block 20 in the internal space of the housing 2, and may be arranged below the circuit block 20. In this case, among the sensing cases 1, the first case 11 fixed to the circuit block 20 is located above the second case 12, so that the inner bottom surface 125 of the second case 12 is the bottom surface of the sensing space Sp1. Bottom surface). Therefore, when the covering body 7 is provided only in one of the first case 11 and the second case 12, the covering body 7 is provided in the second case 12 which is in the direction of gravity (downward) when viewed from the sensing space Sp1. Is preferable.

Further, the smoke detector 10 is not limited to the configuration of being attached to the ceiling of the facility, and may be attached to, for example, the wall surface of the facility as a construction surface, the side surface of furniture, or the like.

Further, the covering body 7 may cover the entire surface 101 of the case body 110. The covering body 7 is not limited to oil, and may be composed of a liquid or gel-like substance other than oil. Further, the thickness T1 of the covering body 7 covering the surface 101 on the first case 11 side, that is, the (first) inner bottom surface 131, and the covering body covering the surface 101 on the second case 12 side, that is, the (second) inner bottom surface 125. The thickness T2 of 7 may be different from each other.

(Embodiment 2)
As shown in FIGS. 9A and 9B, the sensing case 1A according to the present embodiment is different from the sensing case 1 according to the first embodiment in the aspect of the covering body 7A. Hereinafter, the same configurations as those in the first embodiment will be designated by a common reference numeral and description thereof will be omitted as appropriate.

In this embodiment, as shown in FIG. 9B, the covering body 7A is in the form of drops. FIG. 9B is an enlarged schematic view of the region Z1 of FIG. 9A. That is, in the present embodiment, the covering body 7A is formed in a droplet shape that partially covers a certain range of the surface 101 of the case body 110, not in a film shape that covers the entire area. Therefore, even the region of the inner bottom surface 131 of the first case 11 facing (facing) the sensing space Sp1 is not completely covered by the covering body 7A, but a plurality of droplet-shaped covering bodies 7A. Is partially covered with. That is, even in the region of the inner bottom surface 131 of the first case 11 facing (facing) the sensing space Sp1, the portion corresponding to the gap between the plurality of droplet-shaped coverings 7A is relative to the sensing space Sp1. Will be exposed.

Further, in the present embodiment, of the first case 11 and the second case 12, the covering body 7A is provided only in the first case 11. That is, the covering body 7A is not provided on the second case 12, and the entire surface 101 of the second case 12 is exposed.

As a modification of the second embodiment, in the second case 12, at least a part of the surface 101 may be covered with the covering body 7A.

Further, as another modification of the second embodiment, the covering body 7A is not limited to a drop shape, but is, for example, a grid shape, one or more linear shapes, one or more curved lines, or any of these. Appropriate aspects such as combination may be adopted.

The configuration of the second embodiment (including the modified example) can be applied in appropriate combination with the configuration (including the modified example) described in the first embodiment.

(Embodiment 3)
As shown in FIG. 10A, the sensing case 1B according to the present embodiment is different from the sensing case 1 according to the first embodiment in the shape and the like of the wall structure 3. Hereinafter, the same configurations as those in the first embodiment will be designated by a common reference numeral and description thereof will be omitted as appropriate.

In the sensing case 1B, as shown in FIG. 10A, in a plan view, almost no space is generated between the outer peripheral edge of the inner bottom surface 131 of the bottom plate 13 of the first case 11 and the outer peripheral surface 32 of the wall structure 3. Further, in the present embodiment, the auxiliary light-shielding wall 16 (see FIG. 6) is omitted. Further, the shape of each of the plurality of small pieces 30 constituting the wall structure 3 is also different from the sensing case 1 according to the first embodiment. FIG. 10A is a plan view of the sensing block 100 in a state where the second case 12 is removed, that is, the second case 12 is omitted. Further, in FIG. 10A, the inner side surface 31 and the outer side surface 32 are represented by an imaginary line (dashed-dotted line), and the area of the surface 101 of the case body 110 covered with the covering body 7 is shaded (dot hatched). Is attached. That is, in FIG. 10A, the surface 101 of the case body 110 is covered by the covering body 7 over the entire shaded area.

That is, in the present embodiment, in the first case 11, at least the inner region of the outer surface 32 of the wall structure 3 is covered with the covering body 7 on the surface 101. In the first case 11, the covering body 7 is not formed on the surface (lower surface) of the bottom plate 13 opposite to the inner bottom surface 131 and the portion outside the outer surface 32 of the inner bottom surface 131. The surface 101 of the light emitting element holder 8 and the light receiving element holder 9 is covered with the covering body 7 only on the outer peripheral surface (excluding the outer surface 32) in a plan view.

Further, FIG. 10B shows a sensing case 1C according to a modified example of the third embodiment. In the sensing case 1C shown in FIG. 10B, the wall structure 3 is provided not in the first case 11 but in the second case 12. FIG. 10B is a plan view of the sensing block 100 in a state where the second case 12 is removed, that is, the second case 12 is omitted. Therefore, in FIG. 10B, the wall structure 3 is represented by an imaginary line (two-dot chain line). Further, in FIG. 10B, the inner side surface 31 and the outer side surface 32 are represented by an imaginary line (dashed-dotted line), and the area of the surface 101 of the case body 110 covered with the covering body 7 is shaded (dot hatched). Is attached. That is, in FIG. 10B, the surface 101 of the case body 110 is covered by the covering body 7 over the entire shaded area.

Even in the sensing case 1C having such a configuration, when the first case 11 and the second case 12 are connected to each other, the wall structure 3 surrounds the sensing space Sp1 in a plan view as in the sensing case 1B. Will be placed.

The configuration of the third embodiment (including the modified example) can be applied in appropriate combination with the configuration (including the modified example) described in the first embodiment and the second embodiment.

(summary)
As described above, the sensing cases (1,1A to 1C) according to the first aspect are used for the smoke detector (10) including the light emitting element (4) and the light receiving element (5), and the case. It includes a main body (110) and a covering body (7, 7A). The light emitting element (4) outputs light toward the sensing space (Sp1). The light receiving element (5) is arranged at a position where the direct light from the light emitting element (4) is not incident and the scattered light by smoke in the sensing space (Sp1) is incident. The case body (110) surrounds the sensing space (Sp1). The coating (7,7A) is in the form of a liquid or gel. The covering body (7, 7A) covers at least a part of the surface (101) of the case body (110).

According to this aspect, at least a part of the surface (101) of the case body (110) surrounding the sensing space (Sp1) is covered with a liquid or gel-like covering (7,7A). Therefore, for example, when dust (X1) or the like enters or is about to enter the sensing space (Sp1), the dust (X1) or the like is likely to be captured by the covering body (7,7A). When dust (X1) or the like is captured by the covering body (7,7A), a part of the light output from the light emitting element (4) is diffusely reflected by the dust (X1) or the like and received by the light receiving element (5). The possibility of incident on the light can be reduced. As a result, there is an advantage that the increase of stray light can be easily suppressed.

In the sensing cases (1,1A to 1C) according to the second aspect, in the first aspect, when the covering body (7,7A) comes into contact with the dust (X1) existing in the sensing space (Sp1), the dust (7,7A) becomes dusty (7,7A). Wrap at least a part of X1).

According to this aspect, the liquid or gel-like covering (7,7A) captures the dust (X1) by contacting the dust (X1) so as to wrap at least a part of the dust (X1). It will be possible.

In the sensing case (1,1A to 1C) according to the third aspect, in the second aspect, the covering body (7,7A) wraps at least a part of the dust (X1) from the light emitting element (4). Diffuse reflectance in dust (X1) for light is reduced.

According to this aspect, diffuse reflection of light by dust (X1) is less likely to occur, and a part of the light output from the light emitting element (4) is diffusely reflected by dust (X1) to be diffusely reflected by the light receiving element (5). ) Can be significantly reduced.

In the sensing cases (1,1A to 1C) according to the fourth aspect, in any one of the first to third aspects, the covering body (7,7A) is in the form of a film having a thickness (T1, T2).

According to this aspect, a specific region of the surface (101) of the case body (110) can be covered without a gap by the film-like covering body (7, 7A).

In the sensing cases (1,1A to 1C) according to the fifth aspect, in any one of the first to fourth aspects, the surface tension of the covering body (7,7A) is equal to or less than the surface tension of water.

According to this aspect, the wettability of the covering body (7,7A) is relatively high, and when dust (X1) or the like comes into contact with the covering body (7,7A), the dust (X1) or the like is easily captured. ..

In the sensing case (1,1A to 1C) according to the sixth aspect, in any one of the first to fifth aspects, the saturated vapor pressure of the covering body (7,7A) is equal to or less than the saturated vapor pressure of water.

According to this aspect, the covering body (7,7A) is relatively difficult to evaporate, and the covering body (7,7A) is unlikely to decrease due to evaporation.

In the sensing cases (1,1A to 1C) according to the seventh aspect, in any one of the first to sixth aspects, the viscosity of the covering body (7,7A) is 2000 [mPa · s] or less.

According to this aspect, since the viscosity of the covering body (7,7A) is relatively low, when dust (X1) or the like comes into contact with the covering body (7,7A), the dust (X1) or the like is easily captured. ..

In the sensing case (1,1A to 1C) according to the eighth aspect, in any one of the first to seventh aspects, the covering body (7,7A) senses the surface (101) of the case body (110). It covers at least a part of the portion facing the space (Sp1).

According to this aspect, since at least a part of the portion facing the sensing space (Sp1) that easily affects the sensing of smoke is covered with the covering body (7,7A), the dust (X1) that easily affects the sensing accuracy of smoke. ) Etc. can be efficiently captured by the covering body (7,7A).

In the sensing cases (1,1A to 1C) according to the ninth aspect, in any one of the first to eighth aspects, the case body (110) has a wall structure (3) and a pair of inner bottom surfaces (131, 125). ) And. The wall structure (3) surrounds the sensing space (Sp1) when viewed from one direction orthogonal to one plane, and allows smoke to pass through and suppresses the transmission of light. The pair of inner bottom surfaces (131, 125) face each other in one direction. The covering (7,7A) covers at least a part of at least one surface (101) of the wall structure (3) and the pair of inner bottom surfaces (131, 125).

According to this aspect, since at least a part of the portion that easily affects the smoke sensing is covered with the covering (7,7A), dust (X1) or the like that easily affects the smoke sensing accuracy is covered with the covering (7,7A). 7A) enables efficient capture.

In the sensing case (1,1A to 1C) according to the tenth aspect, in any one of the first to ninth aspects, the surface resistivity of the portion of the case body (110) covered with the covering body (7,7A). Is 1.0 × 10 ¹¹ [Ω / sq.] Or more.

According to this aspect, in a portion having a relatively large surface resistivity, it is easy to be charged, it is easy to attract dust (X1) and the like, and it is easy to catch the dust (X1) and the like by the covering body (7,7A). ..

The smoke detector (10) according to the eleventh aspect includes a sensing case (1,1A to 1C) according to any one of the first to tenth aspects, a light emitting element (4), a light receiving element (5), and the like. To be equipped.

According to this aspect, there is an advantage that the increase of stray light can be easily suppressed.

The configurations according to the second to tenth aspects are not essential configurations for the sensing cases (1, 1A to 1C) and can be omitted as appropriate.

1,1A to 1C sensing case 3 wall structure 4 light emitting element 5 light receiving element 7,7A covering body 10 smoke detector 101 surface 110 case body 131,125 inner bottom surface Sp1 sensing space T1, T2 thickness X1 dust

Claims (11)

A light emitting element that outputs light toward the sensing space,
It is used in a smoke detector including a light receiving element that does not receive direct light from the light emitting element and is arranged at a position where scattered light of smoke in the sensing space is incident.
The case body surrounding the sensing space and
A coating that is liquid or gel-like and covers at least a part of the surface of the case body.
Sensing case. When the covering comes into contact with dust existing in the sensing space, it wraps at least a part of the dust.
The sensing case according to claim 1. By wrapping at least a part of the dust with the covering body, the diffuse reflectance of the light from the light emitting element in the dust is reduced.
The sensing case according to claim 2. The covering body is in the form of a film having a thickness.
The sensing case according to any one of claims 1 to 3. The surface tension of the coating is equal to or less than the surface tension of water.
The sensing case according to any one of claims 1 to 4. The saturated vapor pressure of the coating is equal to or less than the saturated vapor pressure of water.
The sensing case according to any one of claims 1 to 5. The viscosity of the coating is 2000 [mPa · s] or less.
The sensing case according to any one of claims 1 to 6. The covering covers at least a part of the surface of the case body facing the sensing space.
The sensing case according to any one of claims 1 to 7. The case body
A wall structure that surrounds the sensing space when viewed from one direction orthogonal to one plane, allows the smoke to pass through, and suppresses the transmission of light.
It has a pair of inner bottom surfaces that face each other in one direction.
The covering covers at least a part of at least one surface of the wall structure and the pair of inner bottom surfaces.
The sensing case according to any one of claims 1 to 8. The surface resistivity of the portion of the case body covered with the covering is 1.0 × 10 ¹¹ [Ω / sq.] Or more.
The sensing case according to any one of claims 1 to 9. The sensing case according to any one of claims 1 to 10 and the sensing case.
With the light emitting element
The light receiving element is provided.
Smoke detectors.

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