JP2023123959A - disaster prevention detector - Google Patents

Abstract

To eliminate pollution of a light receiving window and reduce a workload due to cleaning.SOLUTION: A fire detector 10 is installed on a side wall of a tunnel, exposes to the outside its front face having light receiving glass windows 16 arranged on left and right sides, and detects fires in left or right monitoring areas by observing radiation emitted from a combustion flame entering through the light receiving glass windows 16. A surface of each of the light receiving glass windows 16 is provided with a fouling prevention layer consisting of a moth-eye structure. The moth-eye structure is a two-dimensional arrangement of protrusions with a pitch shorter than a wavelength of light to be detected and a height on a nanometer order, which do not adhere even when contacted by a fouling substance such as dust floating in a tunnel space, thereby preventing pollution of the light receiving glass windows 16 and ensuring stable light transmittance for a long time.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disaster prevention detector that optically detects flames, smoke, etc. caused by a fire and notifies the user.

Conventionally, fire detectors are installed at intervals of, for example, 50 m along the side walls of tunnels, such as highways and motorways, in order to monitor flames caused by vehicle fires. The fire detector monitors radiation from fire flames generated in the tunnel through a light-transmitting light-receiving window, such as infrared radiation. , are arranged continuously so that the detection areas of the adjacent fire detectors overlap in a mutually complementary manner.

Photoelectric separate type smoke detectors are installed in buildings with high ceilings and large spaces such as body and spine halls, auditoriums, and theaters. A separate photoelectric smoke sensor has a transmitter and a receiver placed on the wall with a monitored space in between. Fires are detected based on the rate of dimming.

An outdoor flame detector is also provided to monitor outdoor fires such as arson. The outdoor flame detector detects and reports the flame by receiving radiation energy emitted from the combustion flame in the monitoring compartment through the light receiving window.

JP-A-2002-015393 Japanese Patent Publication No. 2004-355664

By the way, the fire detector installed in the tunnel monitors the contamination of the light-receiving window because the contamination of the light-receiving window increases with the passage of time due to the adhesion of pollutants floating in the environment.

To monitor the contamination of the light receiving window, the test light from the test light source installed in the fire detector is periodically incident on the light receiving window through the detection area side space outside the detector, and the light receiving element inside the detector receives the test light. Dirt compensation is performed by comparing the received light level with that of the initial unpolluted state to correct the decrease in the received light level due to dirt, and the light attenuation rate indicating the degree of dirt is obtained. When it exceeds, a contamination alarm is output.

In addition, the fire detector installed in the tunnel is cleaned at regular intervals because the light-receiving windows of the fire detectors become dirty over time. However, the work of cleaning the light-receiving window must be carried out while restricting traffic in the tunnel, and cleaning the light-receiving window for each fire detector is troublesome and time-consuming. Furthermore, the extent to which contamination progresses on the light-receiving window varies depending on the installation location of the fire detector and the direction of the wind. It varies depending on the left and right sides of the translucent window provided, and for fire detectors with a small degree of contamination progress, unnecessary cleaning work may be performed.

Such a problem caused by contamination of the light-receiving window is the same in a separate photoelectric smoke detector and an outdoor flame detector.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a disaster prevention detector that eliminates contamination of a light receiving window due to adhesion of contaminants floating in the environment, thereby reducing the work load of cleaning work.

(disaster prevention detector)
The present invention is a disaster prevention detector that detects an abnormality by receiving light from the outside through a light receiving window, and is characterized in that an antifouling layer having a moth-eye structure is provided on the surface of the light receiving window.

(Moth-eye structure)
In the moth-eye structure, needle-like or cone-like protrusions having a height on the order of nanometers that decrease in diameter toward the tip are arranged two-dimensionally at a pitch shorter than the wavelength of light to be detected.

(moth eye sheet)
A sheet member having a stain-prevention layer formed thereon is arranged on the surface of the light-receiving window.

(Direct processing of moth-eye structure)
An antifouling layer is processed and formed on the surface of the light receiving window.

(fire detector for tunnel)
The disaster prevention detector is a fire detector that is installed in a tunnel and detects a fire by receiving radiation energy emitted from a combustion flame that is incident through a pair of light receiving windows arranged on the front side,
A light-receiving surface in a fire detector is provided with an anti-fouling layer.

(Photoelectric Separated Smoke Detector)
In the disaster prevention detector, a light transmitter and a light receiver are arranged separately across a monitoring space. A photoelectric separate type smoke sensor for detecting fire, wherein an antifouling layer is provided on the surface of a light receiving window of a light receiver in the photoelectric separate type smoke sensor.

(Anti-fouling layer of light transmission window)
Furthermore, the surface of the light transmission window of the light transmitter in the photoelectric separate smoke sensor is provided with an antifouling layer.

(flame detector to monitor arson)
The disaster prevention detector is a flame detector that is placed in a surveillance area and detects the flame by receiving the radiation energy emitted from the combustion flame incident through the light receiving window. A layer is provided.

(basic effect)
The present invention is a disaster prevention detector that detects an abnormality by receiving light from the outside through a light receiving window. The provided antifouling layer, which has a moth-eye structure, exhibits super water repellency when the contact angle of water on the surface is 150° or more, and the contact resistance is reduced when contaminants floating in the environment come into contact with the surface. Since it is extremely small, it does not adhere to the light-receiving window.

(Effect of moth-eye structure)
In addition, the moth-eye structure consists of two-dimensionally arranged needle-like or cone-like protrusions with heights on the order of nanometers that decrease in diameter toward the tip at a pitch shorter than the wavelength of the light to be detected. In addition to high antifouling properties based on water-based properties, the gradual change in the refractive index of the light incident on the moth-eye structure prevents the light from being reflected, resulting in an extremely low reflectance. The high light-transmitting property of the light-receiving window is ensured by anti-reflection, and the light incident on the light-receiving window from the outside passes through the light receiving window with low loss and enters the violet light element, so that high detection sensitivity can be maintained for a long period of time.

(Effect of moth eye sheet)
In addition, since the sheet member having the antifouling layer formed on the surface of the light receiving window is arranged, for example, by attaching a hard synthetic resin sheet having a moth-eye structure to the light receiving window made of glass, it is possible to easily and easily A light-receiving window having a moth-eye structure formed on the surface can be made.

(Effect of direct processing of moth-eye structure>
In addition, since the antifouling layer is processed and formed on the surface of the light receiving window, for example, in the stage of manufacturing the light receiving window made of glass, the plate glass is pressed against the mold member on which the male mold of the moth-eye structure is formed and is heated. By doing so, it is possible to directly form a moth-eye structure that becomes a male type on the wavefront of flat glass. Even if a finger touches the surface of the target and the dirt adheres, the dirt can be simply and easily wiped off without damaging the moth-eye structure.

(Effect of fire detector for tunnel)
In addition, the disaster prevention detector is a fire detector that is installed in a tunnel and detects a fire by receiving radiation energy emitted from a combustion flame that is incident through a pair of light receiving windows arranged in the front. A contamination-preventing layer is provided on the light-receiving surface of the instrument, so the surface of the light-receiving window has high anti-fouling properties. In combination with the dirt compensation function, it is assumed that it will take a considerable period of time for the light attenuation rate due to dirt to exceed the predetermined dirt threshold and a dirt warning to be output. It is possible to significantly extend the period for regular cleaning.

In addition, the fire detectors installed on the wall of the tunnel have detection areas in both the left and right directions, and are arranged so that the detection areas of the adjacent fire detectors overlap in a mutually complementary manner, resulting in a moth-eye structure. By obtaining a high reflection blocking effect of the light receiving window, the reflection of infrared rays entering from the side detection area where the incident angle becomes large with respect to the optical axis perpendicular to the light receiving window is prevented, and the light is received with low loss. It is possible to maintain high sensitivity to the detection area in the left and right direction due to reflection visits.

(Effect of photoelectric separation type smoke detector)
In addition, the disaster prevention detector has a light transmitter and a light receiver separated by a monitoring space. It is a photoelectric separate type smoke sensor that detects fire based on the base of the smoke detector. , gymnasiums, auditoriums, theaters, and other monitored spaces do not adhere to the light-receiving windows. The burden of work can be underestimated by a large saw.

(Effect of antifouling layer on light transmission window)
Furthermore, since the surface of the light transmitting window of the light transmitter in the photoelectric separate smoke sensor is provided with an antifouling layer, the surface of the light receiving window is highly antifouling, so that pollutants floating in the monitored space can be removed from the light receiver. As with the light receiving window of 1, it does not adhere to the light transmitting window of the light transmitter and can reduce the attenuation of the ray bundle that is directed to the light receiver and transmitted to the monitored space.

(flame detector to monitor arson)
In addition, the disaster prevention detector is a flame detector that is installed in a surveillance area and detects the flame by receiving radiation energy emitted from the combustion flame incident through the light receiving window. Due to the antifouling layer provided, the surface of the light receiving window is highly resistant to contamination, so pollutants floating in the outdoor monitoring space do not adhere to the light receiving window. It is no longer necessary to clean the light-receiving window every time, and the burden of cleaning work can be greatly reduced.

In addition, a hood is provided on the upper side of the light receiving window of the flame detector to protect it from direct sunlight and to prevent rainwater from adhering to it. , the superhydrophobicity of the moth-eye structure prevents water droplets from adhering to the light-receiving window, and the flame monitoring function can be maintained.

FIG. 2 is an explanatory diagram showing a tunnel disaster detection system equipped with fire detectors according to the present invention; It is the perspective view which took out and showed the fire detector. FIG. 10 is an explanatory view showing the light receiving window of the fire waste cotton jar provided with the antifouling layer by the moth-eye structure. FIG. 4 is an explanatory diagram showing the relationship between the water repellency of water droplets adhering to the medium surface and the contact angle; It is an explanatory view showing a detection area of a fire detection device. 1 is an explanatory diagram showing an embodiment of a separate photoelectric smoke sensor according to the present invention; FIG. 1 is an illustration showing an embodiment of a flame detector according to the present invention; FIG.

Below, embodiment of the disaster prevention detector which concerns on this invention is described in detail based on drawing. In addition, the present invention is not limited by the following embodiments.

[Fire detector]
(Overview of Tunnel Disaster Prevention System)
FIG. 1 is an explanatory diagram showing an outline of a tunnel disaster prevention system provided with a fire detector according to the present invention. As shown in FIG. 1, an up-line tunnel 101a and a down-line tunnel 101b are constructed as tunnels of a motorway. Inside the inbound tunnel 101a and the outbound tunnel 101b, fire detectors 10 are installed at intervals of, for example, 25 meters or 50 meters along the walls of the tunnels in the longitudinal direction. The fire detector 10 has two sets of fire detection units so that it has detection areas in both upward and downward directions in the longitudinal direction of the tunnel. The detection area is continuously written so as to overlap each other in a complementary manner, and the radiation from the flame caused by the fire that occurred in the detection area, such as infrared rays, is observed to detect the fire.

Transmission lines 114a and 114b including power supply lines are pulled out from a disaster prevention receiving panel 100 installed in an electric room or the like on the tunnel side to an up line tunnel 101a and a down line tunnel 101b, and a fire detector 10 is connected. A unique address is set in the detector 10 for each line.

In addition, for the disaster prevention receiving panel 100, fire pump equipment 116, cooling pump equipment 118 for ducts, IG slave station equipment (intelligent slave station equipment) 120, ventilation equipment 122, information display board equipment 124, radio rebroadcast A facility 126, a television monitoring facility 128, a lighting facility 130, etc. are provided. Except for the point that the IG slave station facility 120 is connected by a data transmission line, other facilities are connected to the disaster prevention receiver panel 100 by a P-type signal line. Individually connected. Here, the IG slave station equipment 120 is a communication equipment that connects the disaster prevention receiving panel 100 and the remote monitoring control equipment 132, which is an upper equipment provided outside, via a network. The ventilation equipment 122 is equipment that gives energy to the air in the tunnel by means of a high blowing wind speed generated by the operation of a jet fan installed on the ceiling side of the tunnel, thereby generating a ventilation flow in the longitudinal direction of the tunnel.

The sound information display board facility 124 is a facility for notifying a user in the tunnel of an abnormality in the tunnel by displaying it on an electric light indicator. The radio rebroadcast facility 126 is a facility for enabling drivers and others to receive information from road administrators in tunnels. The television monitoring equipment 128 is equipment for confirming the scale and position of the fire, operating the water spray system, and grasping the situation inside the tunnel when conducting evacuation guidance. The lighting equipment 130 is equipment for driving and managing the lighting equipment in the tunnel.

(Appearance of fire detector)
2 is a perspective view showing a fire detector installed in the tunnel of FIG. 1. FIG. As shown in FIG. 2, the fire detector 10 is composed of a detector body 12 and a cover 14. The cover 14 is divided into two left and right slanted surfaces each provided with a light receiving glass window 16 functioning as a light receiving window. A fire is detected by a sensor unit having sensitivity in a predetermined wavelength band installed inside the light receiving glass window 16 . Further, a test light source housing portion 18 is protruded from the upper portion of the light receiving glass window 16 .

Here, in the description of FIG. 2, the XYZ directions are directions orthogonal to each other. The up-down direction is defined as the Z direction, and the front-rear direction is defined as the Z direction. The +X side in the X direction is the right side, the -X side is the left side, the +Y side in the Y direction is the upper side, the -Y side is the lower side, the +Z side in the Z direction is the front side, and the -Z side is the rear side. This point is the same for the XYZ directions in the description of FIGS. 5 to 7, which are the embodiments of the present invention.

The surface of the light-receiving glass window 16 provided in the fire detector 10 of the present embodiment is provided with an antifouling layer having a moth-eye structure.

In the fire detector 10, optical energy from an external detection area is incident on the sensor portion through the left and right light receiving glass windows 16. As shown in FIG. The sensor unit selectively transmits (retains) radiation of 4.4 to 4.5 μm, which is the resonance radiation band of CO ₂ peculiar to flames, from the light energy incident through the light receiving glass window 16 through an optical wavelength band-pass filter. ), the energy of the radiation is detected by a light receiving sensor, photoelectrically converted, and subjected to predetermined processing such as amplification to output a light receiving signal corresponding to the amount of energy.

The judgment of fire by the fire detector 10 takes the relative ratio of the light reception value (light reception signal level) output from the sensor unit and compares it with a predetermined threshold value to judge the presence or absence of flame. When it is detected, the transmission unit is instructed to set fire detection information in a response signal to the call signal matching the own address and to transmit the fire detection information to the disaster prevention receiver panel 100 .

Also, the fire detector 10 receives instructions from the disaster prevention receiving panel 100 and performs a sensitivity test. In the sensitivity test of the fire detector 10, the test light source in the test light source storage unit 18 is driven to emit light, and flame imitation light corresponding to fire flame is made incident on the sensor unit through the light receiving glass window 16, and is output from the sensor unit. The received light value obtained is divided by the reference received light value obtained in the sensitivity test at the time of system start-up to obtain the light attenuation rate. Dirt correction is performed by dividing the light reception value detected by the correction value by the correction value, and a fire is determined from the dirt-corrected light reception value.

Furthermore, when the light attenuation rate obtained by the sensitivity test is equal to or higher than the contamination threshold value or exceeds the contamination threshold value, the fire detector 10 determines that there is a contamination abnormality that makes it impossible to correct contamination on the light receiving glass window 16. An abnormality detection signal is transmitted to the disaster prevention receiving panel 100 to output an abnormality alarm and prepare a cleaning work plan for the fire detector 10 in which an abnormality has been detected.

(Light-receiving glass window with antifouling layer with moth-eye structure)
3A and 3B are explanatory diagrams showing the light-receiving glass window of the fire detector with the antifouling layer having a moth-eye structure, with FIG. 3(A) showing a front view and FIG. 3(B) showing a side view. . FIG. 4 is an explanatory diagram showing the relationship between the water repellency of water droplets adhering to the medium surface and the contact angle, and FIG. 6 is an explanatory diagram showing the detection area of the fire detector.

As shown in FIGS. 3(A) and 3(B), the light-receiving glass window 16 of the fire detector 10 shown in FIG. The antifouling sheet 20 is adhered and fixed.

As shown in FIG. 3C, the contamination-preventing sheet 20 has fine needle-like protrusions 24 on the order of nanometers arranged two-dimensionally on the surface of a sheet body 20a made of hard synthetic resin.

The needle-like projections 24 in the moth-eye structure 22 have a needle-like or cone-like shape that decreases in diameter toward the tip, and have a height H on the order of nanometers. is formed to be shorter than the wavelength of radiation of 4.4 to 4.5 μm emitted from the flame to be detected.

By arranging the antifouling sheet 20 having such a moth-eye structure 22 on the surface of the light-receiving glass window 16, the contact angle of water on the surface of the antifouling sheet 20 becomes 150° or more, thereby obtaining super water repellency. .

The greater the contact angle θ between the surface of the medium and the water droplets, the higher the water repellency when water droplets adhere to the surface of the medium.

FIGS. 4A to 4C show the relationship between the water repellency of water droplets and the contact angle. In FIG. 4A, the water droplet 26a spreads and contacts the medium surface 28a, and the contact angle θa in this case is, for example, 45°, and the water repellency is poor.

FIG. 4B shows a case where a water droplet 26b adheres to another medium surface 28b, the water droplet 26b becomes hemispherical, and the contact angle θb in this case is 90°, for example.

FIG. 4C shows a case where a water droplet 26c adheres to the medium surface 28c of the antifouling sheet having the moth-eye structure of this embodiment. The water droplet 26c has a nearly spherical shape. For example, it is 150°, indicating superhydrophobicity.

As described above, the light-receiving glass window 16 provided with the contamination-visiting sheet 20 of the present embodiment exhibits the superhydrophobicity shown in FIG. 4(C). The resistance is extremely small, and the staining material hardly adheres to the surface of the antifouling sheet 20, so that the light receiving window can be kept clean for a long period of time by eliminating stains on the light receiving window caused by the attachment of the staining material. can.

In addition, the light-receiving glass window 16 of the present embodiment has an anti-fouling sheet 20 of Moth-Eye Kozo on its surface, so that an extremely high anti-reflection effect can be obtained. When light is incident on the light-receiving glass window 16, the refractive index of the air changes rapidly from that of the glass to that of the glass at the interface, so that part of the incident light is reflected, and the reflectance increases as the incident angle increases. It is in.

On the other hand, in this embodiment, when light is incident on the moth-eye structure 22 of the antifouling sheet 20 provided on the surface of the light-receiving glass window 16, needle-like or conical needle-like projections 24 whose diameters decrease toward the tip are formed. The refractive index changes linearly as it passes through, and the reflectance can be made extremely small.

Since the reflectance of the light incident on the light-receiving glass window 16 can be made extremely small in this way, the high translucency of the light-receiving glass window 16 can be maintained, the loss of light passing through the light-receiving glass window 16 can be reduced, and the sensor section can receive light. High detection sensitivity can be maintained when incident light is converted into a received light signal.

In particular, the fire detector 10 of the present embodiment, as shown in plan in FIG. A detection area of α2 is set, and the reflectance increases for light from the side where the incident angle with respect to the optical axis 17 perpendicular to the light receiving glass window 16 increases. However, since the antifouling sheet 20 with the moth-eye structure is provided on the surface of the light receiving glass window 16, the reflectance of the light from the side is extremely low, and the light from the side is efficiently incident and detected. Fire flames can be monitored with high detection sensitivity over the entire area.

(manufacture of moth-eye structure)
The antifouling sheet 20 provided on the surface of the light-receiving glass window 16 is manufactured, for example, as follows. First, a glassy carbon substrate is irradiated with an oxygen ion beam to manufacture a moth-eye structure female mold substrate. Subsequently, by nano-imprinting, UV curable resin is applied to the moth-eye structure female mold substrate to form a moth-eye structure male mold, and an ultra-high-strength resin moth-eye structure sheet that does not break even when touched is duplicated as a contamination prevention sheet 20. do.

Alternatively, the antifouling layer having the moth-eye structure 22 can be directly formed on the surface of the light-receiving glass window 16 . A method of directly forming the moth-eye structure 22 on the glass surface of the light-receiving glass window 16 is, for example, as follows.

First, a female mold substrate having a moth-eye structure is manufactured on a SiC substrate by exposure with electron beam irradiation and dry etching. Subsequently, the female mold substrate is used as the upper mold, the glass substrate is placed in the lower mold, and the upper mold and the lower mold are put together, and heated to a predetermined temperature in a nitrogen gas space, and the lower mold is raised to increase the pressure. In addition, by holding the glass substrate for a certain period of time, the moth-eye structure of the female mold substrate is transferred to the surface of the glass substrate, and the temperature is lowered after releasing the mold.

The method of manufacturing the antifouling sheet 20 provided on the surface of the light-receiving glass window 16 and the method of directly forming the moth-eye structure on the glass surface of the light-receiving glass window 16 are examples, and the manufacturing method is not limited to the above-described manufacturing method, and any manufacturing method can be used. can be

[Photoelectric Separated Smoke Detector]
6A and 6B are explanatory diagrams showing an embodiment of the photoelectric separation type smoke sensor according to the present invention. FIG. 6A shows an installation state of the photoelectric separation type smoke sensor, and FIG. An optical device is shown, and FIG. 6(C) shows a light receiver.

As shown in FIG. 6(A), the light transmitter 30 and the light receiver 32 of the separate photoelectric smoke sensor are arranged facing the walls 34a and 34b adjacent to the ceiling of the monitoring area and facing each other. It is composed of 30a, 32a and covers 30b, 32b.

A light transmitting window 36 is provided on the cover 30b of the light transmitter 30, and a light receiving window 38 is provided on the cover 32b of the light receiver 32. As shown in FIG. The light-transmitting window 36 and the light-receiving window 38 are made of a member, such as polycarbonate, which transmits near-infrared light but blocks visible light.

As shown in FIG. 6B, a light-emitting element 44 using an LED that emits near-infrared light is provided in a main body 30a inside the light-sending window 36 of the light-sending device 30. The near-infrared light generated by the intermittent drive is focused by a light-sending lens 42 and irradiated to the light receiver 32 as a light beam 40 as shown in FIG. 6(A). A cover 30b below the light transmission window 36 of the light transmitter 30 is provided with a monitor light 45 that lights in a monitoring state and a fault light 47 that lights or blinks when a fault occurs.

In this embodiment, a rectangular antifouling sheet 20 is adhered in order to form an antifouling layer having a moth-eye structure at a position covering the front surface of the light sending lens 42 in the light sending window 36 of the light sending device 30 . Fixed.

The antifouling sheet 20 is the same as shown in FIG. 3(C), and has fine needle-like projections 24 on the order of nanometers arranged two-dimensionally on the surface of the sheet using a hard synthetic resin.

The needle-like protrusions 24 in the moth-eye structure 22 have a needle-like or cone-like shape that decreases in diameter toward the tip, and have a height H on the order of nanometers. It is formed so as to be shorter than the near-infrared wavelength of the light flux 40 emitted from the light transmitter 30 and received at 32 .

By arranging the antifouling sheet 20 having such a moth-eye structure 22 on the surface of the light receiving window 38, the contact angle of water on the surface of the antifouling sheet 20 becomes 150° or more as shown in FIG. 4(C). It shows super water repellency by becoming.

For this reason, contact resistance is extremely small when contaminants floating in a monitoring space such as a gymnasium, auditorium, theater, etc. come into contact with the surface of the light receiving window 38, and contaminants hardly adhere to the surface of the antifouling sheet 20. In addition, the light-transmitting property of the light-receiving window 38 can be maintained for a long period of time by removing the contamination of the light-receiving window 38 due to the adhesion of contaminants, and the light-receiving window 38, which requires dangerous high-place work during periodic inspections. It is no longer necessary to perform the cleaning work every time, and the burden of cleaning work can be greatly reduced.

In addition, the light receiving window 38 of the light receiver 32 is provided with the antifouling sheet 20 of Motheye Kozo on the surface thereof, so that an extremely high antireflection effect can be obtained. Since the reflectance of the infrared light incident on the light receiving window 38 can be made extremely small in this way, the light receiving window 38 maintains high translucency, and the near-infrared light from the light transmitter 30 passing through the light receiving window 38 is reduced. When the loss is reduced and the light enters the light-receiving element 48 and is converted into an electric signal, the attenuation of the light caused by the smoke flowing into the monitored space can be accurately detected.

Further, the contact resistance of the light transmitting window 36 of the light transmitter 30 is extremely small when the contaminants floating in the monitoring space contact the surface of the light transmitting window 36, and the contaminant adheres to the surface of the antifouling sheet 20. The light transmitting window 36 is kept free from dirt due to adhesion of contaminants, and the translucency of the light transmitting window 36 is maintained for a long period of time, and the light transmitting window 36 of the light beam 40 irradiated to the monitored space is maintained. Attenuation due to contamination can be prevented.

In the above-described embodiment, the rectangular antifouling sheet 20 is provided at the portion of the light-sending window 36 facing the light-sending lens 42 and the light-receiving window 38 facing the light-receiving lens 46. The antifouling sheet 20 may be provided over the entire light receiving window 38 , or the antifouling layer having a moth-eye structure may be directly formed on the surfaces of the light transmitting window 36 and the light receiving window 38 .

[flame detector]
7A and 7B are explanatory diagrams showing an embodiment of the flame detector according to the present invention, with FIG. 7A showing a front view and FIG. 7B showing a side perspective view.

As shown in FIG. 7, the flame detector 50 of the present embodiment is provided with a light receiving window 54 on the front upper side of the main body 52, and the energy from the flame is received and detected inside the light receiving window 54. A light-receiving element is described. A hood 56 is attached to the light-receiving window 54 to prevent direct sunlight from entering the light-receiving window 54 and rainwater.

A speaker portion 58 is provided on the front surface of the main body 52. The speaker portion 58 accommodates a speaker therein, and an acoustic hole is opened in the front surface of the speaker. The flame detector 50 is installed, for example, on the outer wall of a house where there is a risk of arson, detects flames, and outputs an audio alarm from a speaker unit 58 to inform an abnormality.

Further, in this embodiment, the surface of the light receiving window 54 of the flame detector 50 is adhered and fixed with a stain-prevention sheet to form a stain-prevention layer having a moth-eye structure.

The antifouling sheet of the light-receiving window 54 has the same moth-eye structure 22 as the antifouling sheet 20 shown in FIG. arrayed.

The needle-like projections 24 in the moth-eye structure 22 have a needle-like or cone-like shape that decreases in diameter toward the tip, and have a height H on the order of nanometers. Since the flame detector 50 detects radiation of 4.4 to 4.5 μm emitted from the flame, it is formed so as to be shorter than the wavelength of this radiation.

By placing the antifouling sheet having such a moth-eye structure on the surface of the light-receiving window 54, the surface of the antifouling sheet exhibits superhydrophobicity by increasing the lanceolate angle of water to 150° or more. For this reason, contact resistance is extremely small when contaminants floating outdoors come into contact with the light receiving window 54, and the contaminants hardly adhere to the surface of the antifouling sheet. The light-transmitting property of the light-receiving window 54 can be maintained for a long period of time by eliminating the dirt on the light-receiving window 54, and it is no longer necessary to clean the light-receiving window every time during periodic inspections, which is dangerous work at high altitudes. The burden of cleaning work can be greatly reduced.

In addition, the light-receiving window 54 of the flame detector 50 is provided with a moth-eye antifouling sheet on its surface, so that an extremely high anti-reflection effect can be obtained, and the loss of radiation from the flame passing through the light-receiving window 54 is reduced. and maintain high detection sensitivity.

In the above embodiment, the light receiving window 54 is provided with the antifouling sheet, but the antifouling layer having a moth-eye structure may be directly formed on the surface of the light receiving window 54 .

[Modification of the present invention]
(disaster prevention detector)
In the above embodiment, fire detectors for tunnels, photoelectric separate smoke detectors used in buildings with high ceilings and large spaces, and flame detectors used for monitoring outdoor fires are examples of disaster prevention detectors. This includes, but is not limited to, any detector that receives external light through a light receiving window to detect anomalies.

(Disaster prevention equipment)
In the above embodiment, the light receiving window of the disaster prevention detector is provided with an antifouling layer having a moth-eye structure. The window may be provided with an antifouling layer having a moth-eye structure.

For example, in a tunnel disaster prevention system, a fire extinguisher box with a fire extinguisher door or a fire hydrant system integrated with a fire extinguisher storage unit is installed at regular intervals in the tunnel, and a fire extinguisher is installed in the fire extinguisher door. A viewing window is provided to confirm that the tunnel is stored. To ensure translucency of an observation window over a period of time.

(others)
Moreover, the present invention includes any modifications that do not impair its purpose and advantages, and is not limited by the numerical values shown in the above embodiments.

10: Fire detector 11: Tunnel wall surface 12: Detector main body 14: Cover 16: Light-receiving glass window 16a: Glass main body 18: Test light source storage unit 20: Antifouling sheet 22: Moth-eye structure 24: Acicular projections 26a to 26c: Water droplets 28a to 28c: medium surface 30: light transmitter 32: light receivers 34a, 34b: wall surface 36: light transmitter window 37: monitor lights 38, 54: light receiver window 40: light beam 42: light transmitter lens 44: light emitting element 45 : Fire alarm light 46: Light receiving lens 48: Light receiving element 50: Flame detector 52: Main body 56: Hood 58: Speaker section

Claims (8)

A disaster prevention detector that detects an abnormality by receiving light from the outside through a light receiving window,
A disaster prevention detector, wherein a stain-prevention layer having a moth-eye structure is provided on the surface of the light-receiving window.
In the disaster prevention detector according to claim 1,
The moth-eye structure is a disaster prevention characterized in that needle-like or cone-like projections having a height on the order of nanometers that decrease in diameter toward the tip are arranged two-dimensionally at a pitch shorter than the wavelength of the light to be detected. Detector.
In the disaster prevention detector according to claim 1,
A disaster prevention detector, wherein the sheet member having the antifouling layer formed thereon is arranged on the surface of the light receiving window.
In the disaster prevention detector according to claim 1,
A disaster prevention detector, wherein the antifouling layer is processed and formed on the surface of the light receiving window.
In the disaster prevention detector according to claim 1,
The disaster prevention detector is a fire detector that is installed in a tunnel and detects a fire by receiving radiation energy emitted from a combustion flame that is incident through a pair of light-receiving glass windows arranged on the front side,
A disaster prevention detector, wherein the antifouling layer is provided on the surface of the light-receiving glass window of the fire detector.
In the disaster prevention detector according to claim 1,
In the disaster prevention detector, a light transmitter and a light receiver are separately arranged with a monitoring space interposed therebetween. is a separate photoelectric smoke detector that detects fire based on the rate of
A disaster prevention detector, wherein the antifouling layer is provided on the surface of the light receiving window of the light receiver in the photoelectric separation type smoke sensor.
In the disaster prevention detector according to claim 6,
Further, the disaster prevention detector, wherein the antifouling layer is provided on the surface of the light transmission window of the light transmitter in the photoelectric separation type smoke sensor.
In the disaster prevention detector according to claim 1,
The disaster prevention detector is a flame detector that is placed in a surveillance area and receives radiation energy emitted from a combustion flame incident through a light receiving window to detect the flame,
A disaster prevention detector, wherein the antifouling layer is provided on the surface of the light receiving window of the flame detector.

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