JP2545772Y2 - Smoke detector - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a light emitting unit for emitting irradiation light to smoke in a detected area, and a light emitting unit for receiving signal light reflected by smoke in the detected area. The present invention relates to a smoke detector having a light receiving section, wherein the light receiving section detects the presence or absence of an object to be detected based on a change in the amount of received light.

<Prior Art> Conventionally, this type of smoke detector has a light emitting unit 1 as shown in FIG.
A light emitting side fixed case 3 in which a light emitting element 2 is provided,
A light-receiving side fixed case 6 in which a light-receiving element 5 is provided as the light-receiving section 4 is provided. The two fixed cases 3, 6 are connected so that the optical axes of the light-emitting element 2 and the light-receiving element 5 intersect at about 90 degrees.
It is stored in the outer case P.

When there is smoke 9, the irradiation light emitted from the light emitting element 2 is reflected light (signal light) S 1 reflected by the smoke 9.
And the reflected light (noise light) S2 reflected by the outer case P or the like is incident on the light receiving element 5.
Further, disturbance light (external noise) S0 which is incident through the smoke inflow / outflow slit H provided in the outer case P tends to enter the light receiving element 5.

However, the signal light S1 and the noise light S2 enter the light receiving element 5 because the light receiving unit 4 includes the visible light blocking body 8.

On the other hand, when there is no smoke 9, only the noise light S <b> 2 reflected by the outer case P enters the light receiving element 5.

These lights are converted into electric signals by the light receiving element 5 and amplified. When the smoke 9 is present, the amount of light incident on the light receiving element 5 is increased by the amount of the signal light S1 as compared with the case where the smoke 9 is not present. Has been detected.

At this time, since the signal light S1 is very small, it is necessary to reduce the noise light S2 as compared with the signal light S1 in order to improve the detection accuracy. Therefore, slit plates 7a and 7b are provided in front of the light emitting element 2 and the light receiving element 5 so as to narrow the directivity angle of the light receiving and emitting element and reduce the intervention of the noise light S2.

Here, if the hole diameter of the slit plate 7b is reduced, the directional angle of the light receiving / emitting element is reduced. However, it is only signal light S1
Also reduces the amount of light. Therefore, in order to obtain a high directivity even when the hole diameter of the slit plate 7b is large to some extent, the light receiving and emitting element itself is, for example, a high directivity type such as a can type, and the noise light S2 reaching the light receiving element 5 is reduced. For this purpose, the fixed cases 3 and 6 are designed so that the distance between the slit plates 7a and 7b and the light emitting and receiving elements 2 and 5 is increased.

Further, the visible light blocking member 8 allows all the incident light to be blocked by the blocking member 8.
The area is larger than the hole diameter of the slit plate 7b so that the slit plate 7b is cut by visible light, and the slit plate 7b is in close contact with the slit plate 7b. The reason is as follows. If the slit plate 7b and the visible light shield 8 are placed apart from each other, light of a wide range including the noise light S2 is scattered by the light scattering on the surface of the visible light shield 8 as shown in FIG. The light reaches the light receiving element 5. In contrast, when the slit plate 7b and the visible light shield 8 are in close contact, light scattering on the surface of the visible light shield occurs, but the light detection area is limited by the range of the hole diameter of the slit plate 7b. , Noise light S2 from a place wider than the directional angle narrowed by the slit plate 7b
Is less affected.

<Problem to be solved by the invention> However, at the position of the visible light shield 8 of the smoke detector,
It is required that the front and back surfaces of the visible light shield 8 be flat, not scratched, and free of dirt, dust, and the like.

For this reason, for example, if smoke 9 or dust in the air adheres as the use time elapses, the scattering of light on the surface of the visible light shield 8 cannot be ignored and the signal light
In the state without S1 (only the noise light S2), the amplified electric signal is saturated, leading to malfunction of the smoke detector.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a smoke detector that can reduce the influence of light scattering by a visible light blocker and can prevent malfunction from occurring.

<Means for Solving the Problem> As shown in FIG. 1, the problem solving means according to the first aspect of the present invention includes a light emitting unit 16 for emitting irradiation light to smoke 15 in a detected area R, A light receiving unit 17 for receiving the signal light S1 reflected by the smoke 15, and the light receiving unit 17
A light receiving element 21, a fixed case 22 in which a light receiving window 17a for receiving the reflected signal light S1 from the smoke 15 and receiving the reflected light S1 from the smoke 15 is formed, and the adopting window 17a and the light receiving element 21. And a visible light blocker 24 for blocking visible light that is disturbance light S0 interposed between the visible light blocker 24. The signal light S1 from the smoke 15 is held by being covered by a part of the inner wall of the fixed case 22 so as to be substantially the same as the element 21.
It is arranged in close contact with the light receiving element 21 from the lighting window 17a so as to restrict the incidence of other light.

As shown in FIG. 2, the problem solving means according to the second aspect of the present invention includes a light emitting section 16 for emitting irradiation light to smoke 15 in the detection area R, and a signal light reflected by the smoke 15 in the detection area. S1
And a light receiving unit 17 for receiving light.
In a smoke detector comprising a light receiving element 21 and a fixed case 22 in which a light receiving window 17a for receiving the reflected signal light S1 from the smoke 15 and receiving the reflected light S1 from the smoke 15 is formed.
Inside the light receiving element 21, there is disposed a visible light blocking member 24 that covers the light receiving chip 21d with a visible light cutting resin that blocks visible light that is disturbance light, and corresponds to a front end of the light receiving element 21. The inner wall of the fixed case 22 at a position where the light receiving element 21 protrudes is formed, and an opening (circular hole 37) serving as a light transmission area of substantially the same size as the light receiving element 21 is formed at the center thereof.

<Operation> In the means for solving problems according to claim 1, when the smoke 15 is in the detection region R, the light emitted from the light emitting element 18
And is incident on the light receiving element 21 as the signal light S1 through the lighting window 17a and the visible light blocking member 24.

At this time, since the visible light blocking member 24 is formed to have substantially the same diameter as the light receiving element 21 and is disposed closely to the light receiving element 21 from the lighting window 17a, smoke on the surface of the visible light blocking member 24. Even if dirt and scratches on the dents and the like 15 make it easy to scatter light, (1) most of the light other than the signal light S1 from outside the detection region R is mostly on the surface side of the visible light shield 24. At this time, the light is restricted by a part of the inner wall of the fixed case 22, and the light other than the signal light S1 is incident outside the effective area of the visible light shield 24 and
Do not reach.

(2) The signal light S1 from the detected area R is
Almost all light is scattered on the surface of the light receiving element 21
Incident as signal light.

Therefore, even if light is scattered by the visible light blocker 24, it is possible to reduce the incidence of light other than the signal light S1 on the light receiving element 21 without reducing the signal light S1, thereby causing the smoke detector to malfunction. Can be prevented.

According to claim 2, light other than the signal light S1 from outside the detection region R is incident on a part of the inner wall of the fixed case 22, and the light receiving element
Do not reach 21. Then, the signal light S1 from the detected region R
Reaches the light receiving element 21 through the opening. Here, since visible light is blocked by the visible light blocker 24 provided inside the light receiving element 21, there is no need to provide a visible light cut filter in front of the light receiving element 21 and the number of parts can be reduced. obtain.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

[First embodiment] Fig. 1 is a sectional view showing a smoke detector according to a first embodiment of the present invention.

As shown, the smoke detector of the present embodiment includes a light emitting unit 16 that emits light to the smoke 15 in the detection area R, and a smoke 15 in the detection area R.
And a light receiving unit 17 that receives the signal light S1 reflected by the light receiving unit.

The light emitting section 16 includes a light emitting element 18 that emits light to the smoke 15.
The light-emitting side fixed case 19 in which the light-emitting element 18 is housed and the light-emitting window 16a for projecting the irradiation light of the light-emitting element 18 to the smoke 15 is formed, and is disposed in close contact with the light-emitting window 16a. A diaphragm window 16b for focusing light from the light emitting element 18 and irradiating the smoke 15 with the light
And a light-emitting side slit plate 16c attached thereto.

The light receiving unit 17 includes a light receiving element 21, a light receiving side fixed case 22 in which a light receiving window 17a for receiving the light receiving element 21 and receiving the reflected signal light S1 from the smoke 15 to the light receiving element 21 is formed, and the light receiving window. 1
A light-receiving-side slit plate 17c with an aperture window 17b for narrowing down the signal light S1 from the smoke 15 and closely receiving the light S1 from the smoke 15 and interposed between the slit plate 17c and the light-receiving element 21 Visible light blocker that blocks visible light that is disturbed light S0
24 and have.

The light-emitting element 18 uses a near-infrared light-emitting diode or the like in order to distinguish it from disturbance light that is visible light, and is disposed at a rear portion in the light-emitting side fixed case 19.

As the light receiving element 21, a can type is used for increasing reliability in a vehicle or the like, and a cylindrical body 21a is used.
A stem 21b attached to the rear end of the cylindrical body 21a; a light receiving chip 21d such as a photodiode mounted on the upper surface of the stem 21b and internally connected by a gold wire 21c; and a front of the light receiving chip 21d. And a condenser lens 21e for condensing the incident light on the light receiving chip 21d. The light receiving element 21 is disposed at a rear portion in the light receiving side fixed case 22.

The two fixed cases 19 and 22 are fixed to the connecting portion 31 such that the optical axes of the light emitting element 18 and the light receiving element 21 intersect at about 90 degrees, and are housed in the outer case P. This exterior case P is a box-shaped one having a number of smoke inflow / outflow slits H for taking in smoke 15 inside.

The central part of the inner wall of the light-receiving side fixed case 22, that is, the light-receiving element 21
A holding wall 36 for holding the visible light blocking body 24 is formed at a position corresponding to the front end of the holding wall 36, and a circular hole for engaging with the visible light blocking body 24 is formed at the center of the holding wall 36. 37 are drilled.

The visible light blocker 24 is a visible light cut filter plate, and its effective area, that is, the light transmission region, is formed to have substantially the same diameter as the lens 21e of the light receiving element 21. Then, the visible light blocker 24 extends from the lighting window 17a to the back of the light receiving element 21 so as to regulate the incidence of light other than the reflected light from the smoke 15.
And is engaged with an engaging groove 39 formed in the hole wall of the circular hole 37 of the holding wall 36.

In FIG. 1, R is a detected area,
It is a region surrounded by AA, BB, CC and DD.

In the above configuration, when the smoke 15 is within the detection region R, the light emitted from the light emitting element 18 is irregularly reflected by the smoke 15,
The light enters the light receiving element 21 as the signal light S1 through the aperture window 17b of the slit plate 17c and the visible light shield 24.

At this time, since the visible light blocking member 24 is formed to have substantially the same diameter as the light receiving element 21 and is disposed closely to the light receiving element 21 from the lighting window 17a, smoke on the surface of the visible light blocking member 24. Even if the dirt or scratches of the 15 dirts and the like make it easy to cause light scattering, (1) most of the noise light S2 from outside the detection area R enters outside the effective area of the visible light shield 24. Therefore, it does not reach the light receiving element 21.

(2) The signal light S1 from the detected area R is
Almost all light is scattered on the surface of the light receiving element 21
Incident as signal light.

Therefore, even if light is scattered by the visible light blocker 24, it is possible to reduce the incidence of the noise light S2 on the light receiving element 21 without reducing the signal light S1, thereby preventing malfunction of the smoke detector. It becomes possible.

[Second embodiment] Fig. 2 is a sectional view of a light receiving element in a smoke detector according to a second embodiment of the present invention.

As shown in FIG. 2, the smoke detector of the present embodiment has a visible light blocking body 24 disposed inside a light receiving element 21.
The light receiving chip 21d is mounted on the stem 21b by a conventional method, and internally connected by a gold wire 21c, and then the light receiving chip 21d is covered with a visible light cut resin by potting to form the visible light blocking body 24. ing.

The rest of the configuration is the same as that of the first embodiment, and the structure is such that the visible light blocker made of the visible light cut filter plate of the first embodiment is eliminated from the fixed case 22.

In the above configuration, the action of the visible light cut is
Since the process is performed using the visible light cut resin provided in the inside of the light receiving element 21, it is not necessary to provide a visible light cut filter in front of the light receiving element 21, and the number of components can be reduced.

Further, since the visible light shield 24 can be prevented from coming into contact with the outside air, the surface of the visible light shield 24 is not stained, fogged by smoke 15 or damaged. Further, even if the surface of the lens 21e is stained or adhered to and the light is scattered, the influence of the noise light S2 can be reduced as in the first embodiment.

It should be noted that the present invention is not limited to the above embodiment, and it is needless to say that many modifications and changes can be made to the above embodiment within the scope of the present invention.

For example, the positional relationship between the cases 19 and 22 is such that the optical axes of the light emitting element 18 and the light receiving element 21 intersect at about 90 degrees, but in addition to this relationship, the light receiving element 21 can receive the signal light. Any suitable positional relationship is sufficient.

Further, in the second embodiment, the visible light blocking member 24 may be formed by applying a visible light cutting resin after covering with a silicone resin for chip protection.

<Effects of the Invention> As is clear from the above description, according to the first aspect of the present invention, the visible light blocking body has the inner wall of the fixed case such that the effective area on the front side and the back side is substantially the same as that of the light receiving element. Since it is partially covered and held, and is placed in close contact with the light-receiving element from the lighting window, light scattering may occur due to dirt or scratches such as smoke tar on the surface of the visible light shield. Even if it becomes easy, (1) Most of the light other than the signal light from outside the detected area will enter a part of the inner wall of the fixed case, and will not enter the effective area of the visible light shield. , Does not reach the light receiving element.

(2) Even if the signal light from the detection area is scattered on the surface of the visible light blocking body, almost all light enters the light receiving element as signal light.

Therefore, light incident within the effective area of the visible light shield becomes signal light from the detection region, and the signal light is scattered on the surface of the visible light shield, without reducing the signal light. Light other than the signal light can be prevented from entering the light receiving element, and malfunction of the smoke detector can be prevented.

According to the second aspect of the present invention, a visible light blocker is provided inside the light receiving element, the light receiving chip being covered with a visible light cut resin for blocking visible light of disturbance light, and corresponds to the front end of the light receiving element. The inner wall of the fixed case at the position protrudes, and an opening is formed in the center of the fixed case as a light transmission area of substantially the same size as the light receiving element. As a result, only the signal light can be incident on the light receiving element, the influence of light other than the signal light can be reduced, and malfunction of the smoke detector can be prevented.

Further, a visible light blocker can be provided only by performing a process such as potting the visible light cut resin so as to cover the light receiving chip at the time of manufacturing the light receiving element, and a visible light cut filter is provided as a separate member in front of the light receiving element. There is no need to provide them, and there is an excellent effect that the number of parts can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a smoke detector according to a first embodiment of the present invention, and FIG. 2 is a sectional view of a light receiving element in the smoke detector according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view of a conventional smoke detector, and FIG. 4 is a partially enlarged cross-sectional view showing another conventional proposal example. 15: smoke, 16: light emitting part, 17: light receiving part, 17a: daylighting window, 21: light receiving element, 22: fixed case on the light receiving side, 24: visible light shield, S0: disturbance light, S1: signal light, S2: Noise light.

Claims (2)

(57) [Scope of request for utility model registration] 1. A light emitting section for emitting light to irradiate smoke in a detected area, and a light receiving section for receiving signal light reflected by the smoke in the detected area, the light receiving section comprising a light receiving section. A fixed case in which a light receiving window is formed for storing the light receiving element and receiving the reflected signal light from smoke into the light receiving element,
In a smoke detector comprising a visible light interceptor for intercepting visible light that is disturbance light interposed between the lighting window and the light receiving element, the visible light interceptor has a front side and a rear side. The light receiving element is covered and held by a part of the inner wall of the fixed case so that an effective area is substantially the same as the light receiving element, and is deepened from the lighting window so as to regulate the incidence of light other than signal light from smoke. Smoke detector characterized by being arranged in close contact with. 2. A light emitting section for emitting light to irradiate smoke in a detected area, and a light receiving section for receiving signal light reflected by the smoke in the detected area. In a smoke detector including an element and a fixed case in which a light receiving window is formed to house the light receiving element and receive reflected signal light from smoke to the light receiving element, the inside of the light receiving element is exposed to disturbance light. A visible light blocker, which covers the light receiving chip with a visible light cut resin that blocks a certain visible light, is provided, and the fixed case inner wall at a position corresponding to the front end of the light receiving element is protruded, and the center thereof is provided. A smoke detector, wherein an opening is formed in the portion to be a light transmission area having substantially the same size as the light receiving element.