JP2991890B2 - Infrared radiation suppressor, radar dome provided with the same, and moving object - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared radiation suppressor. More specifically, the present invention relates to an infrared radiation suppressor that suppresses infrared radiation radiated from an outer surface of a radar facility or defense equipment and transmits or absorbs radio waves.

[0002] Here, the radio wave is an electromagnetic wave having a frequency lower than that of infrared rays and used for electric communication.

[0003]

2. Description of the Related Art Defense equipment or defense facilities such as tanks, armored vehicles, military trucks, helicopters, ships, ground radar facilities, and the like, require a large amount of heat from a heat source such as a power generation unit, a cooling device, or an air conditioner to move outward. Emit infrared light. Such equipment or facilities are easily captured and missed by missiles or shells that track targets while sensing infrared radiation. Therefore, various means have been proposed in the past to conceal, protect, and enhance the tactical effect of the equipment or facility from such attacks.

For example, Japanese Patent Application Laid-Open No. 52-54 discloses a technique related to a technique for avoiding catching from a flying object such as a missile that tracks a target while sensing infrared rays.
No. 299, “Infrared guided bullet protected device”, tow a simulated heat source,
As shown in the "concealment device" described in JP-A-7-65600, it is considered that water is atomized and diffused to form a smoke screen composed of water particles. However, the device is large and complicated, and is not always suitable for practical use. In addition, as shown in "Infrared radiation reduction device for ships" described in JP-A-56-116583 and JP-A-57-209490, an infrared absorbing plate is arranged at a required distance from a heat source. Or, it has been proposed to cool the absorption plate with water, but even if these methods can shield infrared rays from a heat source, it is not possible to suppress the infrared radiation from the absorption plate itself, to suppress this In addition, the absorption plate must always be forcibly cooled by air cooling, water cooling, or the like, which poses a serious problem in practical use.

On the other hand, according to Kirchhoff's law, the emissivity ε of an opaque body is expressed by ε = 1−R, where R is the reflectivity. Suggest small. Therefore, in order to block infrared radiation, it is desirable to use an infrared reflector. However, infrared reflectors such as aluminum mirrors and gold mirrors simultaneously reflect visible light well. Therefore, when the outer surface of the vehicle is covered with only these materials, the emission of infrared rays can be surely suppressed, but there is a problem that the infrared rays are visually recognized by reflected light of visible light.

In order to improve this problem, for example, as shown in “Selective absorption surface for solar heat collector” by Takashi Yoshida, Applied Physics Vol. 45, No. 5, Al-Ge-SiO.
By having a three-layer structure, the reflectance of infrared rays is high,
Since the reflectance of visible light can be reduced, infrared rays can be adjusted by adjusting the material, thickness, number of layers, and the like of such a laminated structure of “metal / visible semiconductor / dielectric film”. Thus, it is possible to obtain a color with high camouflage, which has a high reflectance and makes it difficult to visually recognize the reflected light of visible light, such as green or blue. By covering the defense equipment with this material, it is difficult to visually recognize the defense equipment, and furthermore, the radiation of infrared rays can be suppressed.

[0007]

However, since the laminate does not transmit radio waves because it contains a metal layer, it can be used for a radar dome of a terrestrial radar facility or an aircraft, a front panel of a radar antenna, or the like. There is a problem that can not be.

Further, since this metal layer reflects radio waves, even if it can suppress the emission of infrared rays, it does not give any improvement to a radar detecting device.

The present invention has been made in order to solve such a problem, and provides an infrared radiation suppressor which can suppress infrared radiation from defense equipment and has a function of transmitting or absorbing radio waves. The purpose is to:

[0010]

The infrared radiation suppressor of the present invention has a laminated film of a semiconductor layer and a dielectric layer that transmit radio waves formed on the surface of a substrate, and the laminated film is an infrared reflecting film that reflects infrared rays. And a visible light reflecting film portion that reflects light of a specific wavelength of visible light at a desired reflectance.

If the substrate is formed of a dielectric material that transmits radio waves without absorbing them, it can be provided on the radar dome or the front surface of the antenna, so that it is possible to avoid trapping from enemies and operate the radar.

Further, if the substrate is made of a radio wave absorber, it can be provided on the surface of an infrared radiating portion of a moving object having a portion that radiates infrared rays at a high temperature, such as an engine of a vehicle, an aircraft or a ship. In addition, since the emission of infrared rays can be suppressed and the reflection of radio waves from radar or the like can be prevented, capture from enemies by both infrared rays and radar can be avoided.

The laminated film of the infrared reflecting film portion has a semiconductor layer made of a high refractive index material having an optical thickness of λ / 4 and an optical film thickness made of a low refractive index material having a wavelength of infrared light to be reflected, λ. And the dielectric layers are alternately laminated from the viewpoint of improving the reflectance of infrared light having a desired wavelength λ.

The optical film thickness of each layer of the laminated film in the infrared reflection film portion is 3-5 μm wavelength and / or 8-13 μm.
The setting for the wavelength of m is preferable in that the radiation of infrared rays used for capturing can be efficiently prevented.

The visible light reflecting film portion may be formed by providing a dielectric layer that reflects visible light of a specific wavelength on a semiconductor layer that is opaque to visible light.
It is preferable in that it reflects light of a specific wavelength of visible light.

According to a second aspect of the present invention, there is provided a radar dome provided with the infrared radiation suppressor according to the second aspect at least on the outer surface of the radar dome or in the vicinity thereof.

It is preferable that at least two types of reflected light regions of camouflage color are provided on the surface of the infrared radiation suppressor from the viewpoint of preventing visual recognition by the naked eye and camouflage.

Further, the moving object according to the present invention has a portion that radiates infrared rays, and is a moving object that moves while radiating infrared rays, wherein an infrared ray is provided on an outer surface of the portion that radiates infrared rays. A radiation suppressor is provided.

Here, the term "moving object" refers to a vehicle, an aircraft, a helicopter, a ship, or other defense equipment that moves while emitting infrared rays.

It is preferable that at least two types of reflected light regions of camouflage color are provided on the surface of the infrared radiation suppressor from the viewpoint of preventing visual recognition by the naked eye and camouflage.

[0021]

According to the infrared radiation suppressor of the present invention, the semiconductor layer and the dielectric layer are laminated so that the reflectance to infrared rays is high and the visible light of a specific wavelength is reflected at a desired reflectance. Therefore, the emissivity of infrared rays to the outside can be suppressed low, and reflected visible light can be made inconspicuous.

Further, according to the radar dome of the present invention, an infrared radiation suppressor in which an infrared reflection film portion and a visible light reflection film portion are provided on a substrate made of a dielectric material that transmits radio waves without absorbing them is provided. Or, because it is placed on the outer surface of the radar dome, the infrared radiation of the radar dome is suppressed without interfering with the transmission and reception of radar, and the visible light is not noticeable because the reflectance of visible light is adjusted. can do.

Further, a moving object such as a vehicle or an aircraft according to the present invention is provided with an infrared radiation suppressor having the infrared reflection film portion and the visible light reflection film portion provided on the surface of a material absorbing radio waves, for ships, vehicles and aircrafts. Alternatively, by attaching it to the outer surface of an infrared radiating part such as defense equipment or the like, it will not be detected by radar, suppresses infrared radiation from moving objects, and adjusts the reflectance of visible light so that it is visible. It can also be inconspicuous for light.

[0024]

Next, an infrared radiation suppressor according to the present invention will be described with reference to the drawings.

In the infrared radiation suppressor of the present invention, for example, as shown in the sectional view of FIG. 1, a semiconductor layer made of, for example, germanium and cerium fluoride and a dielectric layer are alternately formed on the surface of a substrate 1 in an odd number. A multilayer film 2 is provided in which layers are stacked, and the multilayer film 2 functions as an infrared reflecting film that reflects infrared light. A titania (TiO ₂ ) layer 3 and silicon dioxide (Si) are further formed on the uppermost semiconductor layer of the multilayer film 2.
O ₂ ) layer 4 and other dielectric layers are formed.
A visible light reflecting film that reflects only a specific wavelength of visible light at a desired reflectance is formed together with the uppermost semiconductor layer.

The above-mentioned infrared reflecting film portion transmits radio waves and reflects infrared rays. When the beams reflected from all the boundaries of the alternating layers reach the incident surface, they have the same phase, so that the beams strengthen each other. In order to achieve the above, the optical thickness (geometric thickness × refractive index) of the semiconductor layer and the dielectric layer forming the multilayer film 2 is set to λ / 4 for the wavelength λ of the infrared light to be reflected. Preferably. It is known that the difference between the refractive index of the semiconductor layer and the refractive index of the dielectric layer is preferably large in order to increase the reflectance of infrared rays. Germanium, which is mainly used as a semiconductor layer, has a refractive index of about 4, and a dielectric layer has a low refractive index, and has good adhesion and rarely causes blemishes or fogging. The present inventors have found that cerium fluoride (CeF ₃ ) which is easy to use is preferable.

It is preferable that the wavelength of the infrared ray for increasing the reflectance particularly in the infrared ray is set in the range of 3 to 5 μm and 8 to 13 μm. This is because the infrared light used to capture ordinary defense equipment often has a wavelength in this range, and the optical film thickness is set to λ / 4 according to the wavelength in this range.
It is preferable that In addition, the amount of change in the infrared radiation energy due to the temperature rise of the object is large at 3 to 5 μm, and relatively small at 8 to 13 μm.
It is preferable to provide a reflectance of 60% or more for infrared rays having a wavelength of .mu.m so as to increase the effect of suppressing infrared radiation, and 35% for infrared rays having a wavelength of 8 to 13 .mu.m.
Even with the above reflectance, the effect of suppressing infrared radiation is sufficient.

With respect to the visible light reflecting film, a reflecting film for the wavelength to be reflected can be formed by using an anti-reflection film designing technique in the optical multilayer film. For example, to reflect orange, an optical film is formed on the germanium layer. 94nm thick
To reflect yellow, a titania layer with an optical film thickness of 110 nm and an optical film thickness of 180 n were used to reflect yellow.
In order to reflect green, a germanium layer, a titania layer with an optical film thickness of 110 nm and a silicon dioxide layer with an optical film thickness of 150 nm are laminated. A zirconia layer with a thickness of 125 nm and a magnesium fluoride layer with an optical thickness of 121 nm are laminated, a zinc sulfide layer with an optical thickness of 122 nm is laminated on a germanium layer to reflect purple, and a silicon layer and a sulfide layer to reflect black. It can be obtained by laminating an arsenic layer, a zirconia layer, and a magnesium fluoride layer.

When the above-described infrared radiation suppressor is used in a radar dome or the like, when it is necessary to transmit radio waves, the substrate 1 is made of a dielectric material that transmits radio waves without absorbing radio waves, such as glass, ceramics, plastics, and rubber. It can be obtained by using one kind of body material or a composite material of two or more kinds thereof. In addition, when used for equipment such as ships, vehicles, aircraft, etc., to avoid tracking by radar from enemies, do not reflect radio waves,
By using a bonded body of a metal plate and a magnetic body such as ferrite or a bonded body of a metal plate with rubber or plastics mixed with magnetic powder for the substrate 1, radio waves are absorbed,
An infrared radiation suppressor that reflects only a specific color without emitting infrared light is obtained.

Next, a method for forming the multilayer film 2 formed on the substrate 1 will be described. Each semiconductor layer and the dielectric layer of the multilayer film 2 are formed by electron beam evaporation using a vacuum evaporation apparatus as shown in the sectional view of FIG.

In FIG. 2, reference numeral 5 denotes a vacuum vessel for obtaining a high vacuum, and 6 denotes a dome for mounting a substrate 7 on which a substrate 7 to be vapor-deposited is mounted. The dome is rotated during vapor deposition to increase the uniformity of the film. Numeral 8 denotes a crucible for storing a substance to be deposited, and a substance to be deposited can be moved by a crucible rotating stage 9 to a position where the electron beam emitted from the electron gun 10 hits. The substance heated and evaporated by the electron beam becomes a film on the substrate 7. The thickness of the vapor-deposited film is measured by measuring the film thickness of a monitor substrate 12 with a reflective optical film thickness meter 11 mounted above the vacuum vessel 5, and the vapor-deposited film has a required film thickness. When it becomes, the shutter 13 is closed. Less than,
Similarly, different layers of deposited films are sequentially formed. In each of the examples described later, the formation of the multilayer film was performed by this method.

Next, the present invention will be described in more detail with reference to specific examples.

Embodiment 1 FIG. 1 is an explanatory sectional view showing an embodiment of the infrared radiation suppressor of the present invention. As shown in FIG. 1, the infrared radiation suppressor of this embodiment has a thickness of 7.8 mm.
A multilayer film 2 was formed by alternately stacking seven layers of germanium and cerium fluoride for use as an infrared reflecting film in this order on the surface of the quartz (SiO ₂ ) glass 1 by vacuum evaporation. Since the first three layers of the seven layers reflect infrared rays of 8 to 13 μm, the four layers are adjusted so that the optical film thickness becomes 2.5 μm.
The cerium fluoride of the layer has an optical film thickness of 0.8 μm, and the remaining three layers have an optical film thickness of 1 μm so as to have a function of increasing the reflectance to infrared rays having a wavelength of 3 to 5 μm. The intermediate cerium fluoride layer is an adjustment layer for not canceling out the effects of both. On the multilayer film 2, a titania layer 3 is further formed by an optical film thickness of 110 n by a vacuum evaporation method.
m, and a silicon dioxide layer 4 was sequentially formed in this order so as to have an optical film thickness of 150 nm. The germanium layer, which is the outermost layer of the titania layer 3, silicon dioxide layer 4, and multilayer film 2, has a maximum reflectance of 20% in the visible light region.
Hereinafter, it is formed such that the color of the reflected light becomes green.
In this way, an infrared radiation suppressor having a property of having a high reflectance with respect to infrared rays and reflecting only light of a specific wavelength with a desired reflectance with respect to visible light was produced.

The infrared spectral reflectance of the infrared radiation suppressor thus formed was measured using a Fourier transform infrared spectrophotometer and a reflectance measurement holder manufactured by Horiba, Ltd.
The measurement was performed with reference to an aluminum mirror having an infrared reflectance of 98%. The results are shown in FIG.
The reflectivity slightly decreases for a wavelength of μm,
High reflectivity was obtained for infrared light having a wavelength of μm.

The spectral reflectance in the visible light range is
The measurement was performed using a self-recording spectrophotometer and a reflectance measurement holder manufactured by Shimadzu Corporation with reference to an aluminum mirror having a visible light reflectance of 92%. As a result, as shown in FIG. 14, the reflectance near green having a peak at a wavelength of 570 nm is high.

As shown in FIG. 3 for explaining the transmission characteristics of radio waves, an infrared radiation suppressor 16 is placed between a transmitting antenna horn 14 and a receiving antenna horn 15, Was examined for its radio wave transmission characteristics.
In FIG. 3, reference numerals 17 and 18 indicate a transmitter and a receiver, respectively. The transmittance was measured at a transmission frequency of the transmitter 17 of 10 GHz. As a result, almost no attenuation was observed at -0.3 dB. In addition,
The reason why the thickness of the quartz glass of the substrate is 7.8 mm is that the product of the relative dielectric constant of the substrate and the thickness multiplied by 1/2 with respect to the transmission frequency is an integral multiple of 1/2 of the radio wave wavelength. This is to meet the conditions.

Embodiment 2 FIG. 4 is an explanatory sectional view showing another embodiment of the infrared radiation suppressor of the present invention. As shown in FIG. 4, six layers of germanium and cerium fluoride are alternately laminated in this order on quartz glass 1 having a thickness of 7.8 mm to form a multilayer film 19, and a seventh layer is coated with silicon (Si) 20. did. As in the first embodiment, the first three of the seven layers have an optical thickness of 2.5 μm, the fourth cerium fluoride has a thickness of 0.8 μm, and the remaining three layers have an optical thickness including silicon. Was set to 1 μm. A zirconia (ZrO ₂ ) layer 21 having an optical thickness of 125 nm and a magnesium fluoride (MgF ₂ ) layer 22 having an optical thickness of (A) 1
62 nm and (B) 121 nm were sequentially coated. In this way, the maximum reflectance in the visible light range is 15% or less, and the color of the reflected light is (A) green and (B) blue under natural light, and the reflectance is high for infrared light. An infrared radiation suppressor capable of producing desired reflected light with respect to visible light was manufactured. The reason why the seventh layer is coated with silicon is that the reflectance in the visible light region can be adjusted to 15% or less at maximum by combining zirconia and magnesium fluoride of the dielectric film.

The infrared and visible spectral reflectances of the infrared radiation suppressor thus formed were measured in the same manner as in Example 1. The results are shown in FIGS. 17 and 15, respectively.

The transmission characteristics of the infrared radiation suppressor for radio waves were measured in the same manner as in Example 1. The result hardly attenuated at a transmittance of -0.3 dB.

[Embodiment 3] FIG. 5 is a cross-sectional view showing still another embodiment of the infrared radiation suppressor of the present invention, and FIG. 6 is an explanatory view of a measuring method for examining the radio wave absorption of the infrared radiation suppressor. It is. MgFe ₂ thickness 2.0mm as shown in FIG. 5
On the surface of the dense magnesium ferrite 24 represented by the chemical formula of O _4, the multilayer film 19 made of germanium and cerium fluoride and the silicon layer 2 were formed in the same manner as in the second embodiment.
Next, a dielectric film of a zirconia layer 21 and a magnesium fluoride layer 22 was sequentially coated. The coated ferrite layer 24 is bonded with a 1.5 mm thick stainless steel plate 23 to the surface opposite to the surface on which the multilayer film 19 is formed with an epoxy-based adhesive. And In this way, infrared radiation having radio wave absorption, high reflectivity for infrared light, and characteristics adjusted to reflect light of a specific wavelength at the desired reflectivity for visible light An inhibitor was prepared. In the procedure above, we left the magnesium ferrite and stainless steel plate together with adhesive.
This is to avoid a thermal change of the adhesive caused by heating the substrate during coating.

The infrared and visible spectral reflectances of the infrared radiation suppressor thus formed were measured in the same manner as in Example 1. The results are shown in FIGS. 17 and 15, respectively.

Also, as shown in FIG.
The measurement was performed by irradiating the radio wave from 14 to the infrared radiation suppressor 25 and receiving the reflected wave by the receiving horn 15.
As a result, the reflectance was smaller than -10 dB. The transmitter
The transmission frequency of 17 was set to 10 GHz as in the first embodiment. The laminate of stainless steel plate and magnesium ferrite is
The ferrites are combined so as to absorb 10 GHz radio waves, and the thickness of the ferrite is adjusted according to the frequency of the radio waves to be absorbed.

[Embodiment 4] As another embodiment of the infrared radiation suppressor of the present invention, as shown in FIG. 7, a multilayer of germanium and cerium fluoride is formed on the same ferrite as in Embodiment 3 as in Embodiment 2. A film and silicon are coated, and an arsenic sulfide (As ₂ S ₃ ) layer 26 is further coated thereon with an optical thickness of 134.
nm, the zirconia layer 21 was coated in an optical thickness of 134 nm, and the magnesium fluoride layer 22 was coated in an optical thickness of 138 nm in this order. Arsenic sulfide layer 26, zirconia layer 21, magnesium fluoride layer 22, and silicon layer 20
Is designed so that the maximum reflectance in the visible light range becomes 5% or less, almost absorbs visible light, and becomes black. The coated ferrite layer 24 was bonded to a stainless steel plate 23 in the same manner as in Example 3, and the ferrite layer 24 and the stainless steel plate 23 were used as a radio wave absorber. In this way, infrared radiation having radio wave absorption, high reflectivity for infrared light, and characteristics adjusted to reflect light of a specific wavelength at the desired reflectivity for visible light An inhibitor was prepared.

The infrared and visible spectral reflectances of the infrared radiation suppressor thus formed were measured in the same manner as in Example 1. The measurement results are shown in FIG. 17 and FIG. As is clear from FIG. 14, the reflectance was small over the entire visible light range and the color was black.

The radio wave absorption characteristics of the infrared radiation suppressor were measured in the same manner as in Example 3. As a result, the reflectance was smaller than -10 dB.

Embodiment 5 As still another embodiment of the infrared radiation suppressor of the present invention, as shown in FIG.
Five layers of a multilayer film 27 of silicon and magnesium fluoride having an optical film thickness of 1 μm were coated in this order on a 7.8 mm quartz glass 1 by a vacuum evaporation method. This multilayer film 27
It has a function of reflecting infrared rays of 5 μm with high reflectance. On the silicon which is the outermost layer of the multilayer film 27, the zirconia layer 21 has an optical film thickness of 125 nm and the magnesium fluoride layer 22 has an optical film thickness of (A) 162 nm and (B) 121 nm similarly to the second embodiment. Were sequentially coated. The zirconia layer 21, the magnesium fluoride layer 22, and the silicon layer, which is the outermost layer of the multilayer film 27, have a maximum reflectance of 15% or less in the visible light range, and the color of the reflected light under natural light is (A) Green and (B) are designed to be blue. In this way, an infrared radiation suppressor having characteristics adjusted so that it has a high reflectance with respect to infrared rays and reflects only light having a specific wavelength with respect to visible light at a desired reflectance.

The infrared and visible spectral reflectances of the infrared radiation suppressor thus formed were measured in the same manner as in Example 1. The results are shown in FIG. 18 and FIG.
Are shown below. As is clear from FIG.
A very high reflectance was obtained for the infrared ray having the wavelength of, but the reflectance was lowered for the wavelength of 6 μm or more.

The transmittance of this infrared radiation suppressor for radio waves was measured by the same method as in Example 1, and as a result, the transmittance was -0.15 dB.

[Embodiment 6] As still another embodiment of the infrared radiation suppressor of the present invention, as shown in FIG.
On a 0 mm stainless steel plate 23, 67% by weight of ferrite powder represented by the chemical formula of Fe ₂ O ₃ and carbon fiber 3
A radio wave absorption layer 28 consisting of a plastic plate with a thickness of 1.4 mm dispersed by weight% is laminated, and a further 3.8 m thick is placed on top of it.
Then, a quartz glass plate 29 having a thickness of m was bonded. Here, the carbon fiber is dispersed in a plastic plate for adjusting the dielectric constant of the radio wave absorbing layer 28, and the amount of ferrite powder and the thickness of the glass plate are adjusted so as to form a good radio wave absorbing property. I have. The quartz glass plate 29 is previously coated with a multilayer film 30 of germanium and cerium fluoride having an optical film thickness of 2.5 μm in this order by a vacuum evaporation method. The multilayer film 30 has a function of reflecting infrared rays of 8 to 13 μm with a high reflectance. Further, on the germanium which is the outermost layer of the multilayer film 30, a titania layer 3 and a silicon dioxide layer 4 are coated as a dielectric film similar to the first embodiment, and the maximum reflectance in the visible light region is 20% or less. It is formed so that the color of the reflected light is green. Thus, an infrared radiation suppressor having a property of having a high reflectance with respect to infrared rays and reflecting only light of a specific wavelength with a desired reflectance with respect to visible light was produced. The reason why the radio wave absorbing layer is attached after the procedure is to avoid a thermal change between the plastic and the adhesive due to the heating of the substrate during the coating.

The infrared and visible light spectral reflectances of the infrared radiation suppressor thus formed were measured in the same manner as in Example 1. The results are shown in FIG. 18 and FIG.
Shown in As is clear from FIG. 18, a high reflectance is obtained for infrared rays having a wavelength of 8 to 13 μm,
The reflectance is low for the wavelength of.

Also, as a result of measuring the radio wave absorption characteristics of the infrared radiation suppressor by the same method as in Example 3,
The reflectance was smaller than -25 dB.

[Embodiment 7] As still another embodiment of the infrared radiation suppressor of the present invention, as shown in FIG.
8 mm quartz glass 1 is coated with a multilayer film 2 in which germanium and cerium fluoride are alternately laminated as in Example 1, and a zinc sulfide (ZnS) layer is used as a dielectric film for coating the outermost layer of germanium. 31 is an optical film thickness of (A) 94 nm, (B) 122 nm, and (C) 153
Each of the three types was coated by a vacuum deposition method. This gives a maximum reflectance in the visible range of 50
% Or less and the color of reflected light under natural light (A) is orange,
(B) A purple (C) was blue, and the infrared radiation suppressor had the property of having a high reflectance with respect to infrared rays and reflecting at a desired reflectance with respect to visible light.

The infrared and visible spectral reflectances of the infrared radiation suppressor thus formed were measured in the same manner as in Example 1. The results are shown in FIG. 17 and FIG.
Respectively.

The transmittance of this infrared radiation suppressor for radio waves was measured by the same method as in Example 1, and as a result, the transmittance was -0.2 dB.

Tables 1 and 2 show the transmittance and the reflectance (the radio wave absorption of Examples 3, 4 and 6) of each of the above examples.

[0056]

[Table 1] As can be seen from Table 1, it can be seen that the infrared radiation suppressor of the present invention has a sufficient radio wave transmittance and can be used as a material for a radar dome.

[0057]

[Table 2] As can be seen from Table 2, it can be seen that the infrared radiation suppressor according to the present invention has sufficient radio wave absorption. Therefore, when the infrared radiation suppressor is attached so as to cover a vehicle or the like, it is possible to provide radio wave stealth in addition to suppressing infrared radiation, which has a great practical effect.

[Embodiment 8] Next, the use of the infrared radiation suppressor of the present invention will be described. As shown in FIG.
A radar dome was constructed by fitting the infrared radiation suppressor 32 produced in Example 1 into a plastic angle 33 assembled in a dome shape. The quartz glass used as the substrate in Example 1 was similarly assembled into a dome, and the outside thereof was colored dark green with a polyurethane paint (color number 2314) manufactured by Dainippon Paint Co., Ltd. These two domes are placed outdoors at 20 ° C, the dome is heated to 50 ° C for comparison of infrared radiation, and an infrared imaging device (infrared sensitivity range, manufactured by Mitsubishi Electric Corporation) that can capture infrared radiation as a thermal image 3-5 μm) and in the high wavelength region, the difference in the apparent temperature of the dome is detected by the infrared sensor 34 of a thermo tracer (infrared sensitivity range 8-13 μm) manufactured by NEC Sanei Co., Ltd. The degree of suppression was examined. Table 3 summarizes the results.

[0059]

[Table 3] As is clear from Table 3, it is understood that the radiation of infrared rays is suppressed by assembling the radar dome with the infrared radiation suppressor according to the present invention.

Ninth Embodiment As another embodiment of the use of the infrared radiation suppressor of the present invention, as shown in FIG. 12, the infrared radiation suppressor 35 produced in the third embodiment was heated to a high temperature during operation. Attached to the side of the vehicle 36, for example, a rear fender. The same paint as that used in Example 8 was applied to the vehicle body in advance, and the outer surface of the vehicle was subjected to two types, (A) 50 ° C and (B) 70 ° C. At this time, the infrared ray emitted from the outer surface of the vehicle is transmitted to the infrared sensor
Thus, the degree of suppression of infrared radiation was examined by observing the difference in apparent temperature on the vehicle surface when the radiation suppressor was attached to the vehicle and when it was not attached. The ambient temperature at this time was 20 ° C. The results are shown in Tables 4 and 5.

[Embodiment 10] As still another embodiment of the method of using the infrared radiation suppressor of the present invention, the reflected light in the visible light region produced by Embodiments 3 and 4 becomes green, black and blue. Infrared radiation suppressors 37, 38 and 39,
Each was cut irregularly and affixed to the vehicle in a camouflage form as shown in FIG. Then, the effect of the infrared radiation suppressor produced so as to form the camouflage was confirmed by the same method as in Example 8. The ambient temperature at this time was 20 ° C. The results are shown in Tables 4 and 5.

Table 4 shows the results obtained in Examples 9 and 10.
The outer surface of the vehicle body coated with dark green paint was set to 50 ° C., and the apparent temperature indicated by the infrared sensor was shown when the infrared radiation suppressor was attached to the vehicle body and when it was not attached. Table 5 summarizes the apparent temperature indicated by the infrared sensor when the outer surface of the vehicle body is set at 70 ° C.

[0063]

[Table 4]

[0064]

[Table 5] As is clear from Tables 4 and 5, it is found that the infrared radiation suppressor according to the present invention is installed so as to cover the outer surface of a vehicle or the like, thereby suppressing the emission of infrared radiation.

The vehicle to which the infrared radiation suppressor was attached was placed in a forest, and the vehicle was visually observed to confirm that the vehicle was camouflaged, thereby making it difficult to visually recognize the vehicle. did.

In the above-described embodiment, the operation is performed by the vehicle. However, even if the device is attached to an infrared radiation device such as a ship other than the vehicle, an aircraft, or similar defense equipment, it is possible to suppress the infrared radiation and escape from tracking by a radar or the like. it can.

As described in each of the embodiments, according to FIG. 14, in Embodiments 1 and 6, the reflected light is green with a peak at a wavelength of 570 nm, and in Embodiment 4, light is absorbed over the entire visible light region. Therefore, it becomes black. According to FIG.
Common to all of Examples 2, 3 and 5 (A)
In this case, the wavelength becomes green at 570 nm, and in (B), it becomes blue at 460 nm. According to FIG. 16 (A)
In (B), blue light, (C) due to orange reflected light
Then it becomes purple.

As is clear from FIGS. 17 and 18, the fact that the suppressors of Examples 1 to 4 and 7 have a high reflectivity in the infrared ray having a wavelength of 3 to 13 μm is indirect at the wavelength having a high reflectivity. Suggest that the infrared emissivity is low. Therefore, the infrared radiation suppressor according to the present invention is mounted so as to cover a high-temperature portion such as an engine of a vehicle and an air conditioner,
Even if the temperature of the suppressor itself rises, the amount of infrared radiation from the suppressor is small. Therefore, the infrared radiation from the vehicle can be suppressed without performing cooling such as air cooling or water cooling.

[0069]

According to the infrared radiation suppressor of the present invention, radio waves are not reflected, the reflectivity of infrared rays is high, and the reflectivity for infrared rays is high. In addition, since the reflectance of visible light is adjusted, it becomes inconspicuous with respect to visible light, and can be avoided from being captured by enemies when used in defense equipment.

Also, on the surface of a dielectric material that does not absorb radio waves,
By forming the infrared radiation suppressor of the present invention, the reflectance to infrared rays is high, and it has a property of reflecting only visible light of a specific wavelength at a desired reflectance and transmits a radio wave. Or, if it is placed on the outer surface of the radar dome, it suppresses infrared radiation from the radar dome without hindering radar transmission and reception, and because the reflectance of visible light is adjusted, it is inconspicuous for visible light Hard to be caught by the enemy.

Further, the dielectric and semiconductor multilayer films coated on the surface of a material that absorbs radio waves are applied to the outer surface of the infrared radiation portion of a moving object such as a ship, a vehicle, an aircraft, or other defense equipment. By being attached, it is not detected by a radar, suppresses infrared radiation from a moving object, and is inconspicuous for visible light because the reflectance of visible light is adjusted.

Further, the reflected light in the visible region of the infrared radiation suppressor is one of green, blue, yellow, black or a similar color.
By using two or more of these in combination to form a camouflage, camouflage can be performed in complex backgrounds such as forests and vegetation, and visible light can be obtained. The effect of the concealment for is increased.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an embodiment of an infrared radiation suppressor of the present invention.

FIG. 2 is a cross-sectional explanatory view of a vacuum evaporation apparatus for producing the infrared radiation suppressor of the present invention.

FIG. 3 is an explanatory diagram of a measuring method for examining the radio wave transmission of the infrared radiation suppressor of the present invention.

FIG. 4 is an explanatory sectional view showing another embodiment of the infrared radiation suppressor of the present invention.

FIG. 5 is an explanatory sectional view showing still another embodiment of the infrared radiation suppressor of the present invention.

FIG. 6 is an explanatory view of a measuring method for examining the radio wave absorption of the infrared radiation suppressor of the present invention.

FIG. 7 is an explanatory sectional view showing still another embodiment of the infrared radiation suppressor of the present invention.

FIG. 8 is an explanatory sectional view showing still another embodiment of the infrared radiation suppressor of the present invention.

FIG. 9 is an explanatory sectional view showing still another embodiment of the infrared radiation suppressor of the present invention.

FIG. 10 is an explanatory sectional view showing still another embodiment of the infrared radiation suppressor of the present invention.

FIG. 11 is an explanatory view of a radar dome showing one embodiment of the use of the infrared radiation suppressor of the present invention.

FIG. 12 is an explanatory view of a vehicle in which an infrared radiation suppressor is mounted on a vehicle body, showing an embodiment of a method of using the infrared radiation suppressor of the invention according to claim 14;

FIG. 13 is an explanatory view of a vehicle with a camouflage pattern showing another embodiment of the use of the infrared radiation suppressor of the present invention.

FIG. 14 is a view showing the spectral reflectance in the visible light region of Examples 1, 4 and 6 of the infrared radiation suppressor of the present invention.

FIG. 15 is a view showing the spectral reflectance in the visible light region of Examples 2, 3 and 5 of the infrared radiation suppressor of the present invention.

FIG. 16 is a view showing the spectral reflectance in the visible light range of Example 7 of the infrared radiation suppressor of the present invention.

FIG. 17 shows Examples 1 and 2 of the infrared radiation suppressor of the present invention.
It is a figure which shows the spectral reflectance of infrared rays of 3, 4, and 7.

FIG. 18 is a view showing the spectral reflectance of infrared rays of Examples 5 and 6 of the infrared radiation suppressor of the present invention.

[Explanation of symbols]

 2 Multilayer film 3 Titania layer 4 Silicon dioxide layer 16 Infrared radiation suppressor 19 Multilayer film 20 Silicon layer 21 Zirconia layer 22 Magnesium fluoride layer 23 Stainless steel plate 24 Ferrite layer 25 Infrared radiation suppressor 26 Arsenic sulfide layer 27 Multilayer film 28 Radio wave absorption Layer 29 Quartz glass plate 30 Multilayer film 31 Zinc sulfide layer 32 Infrared radiation suppressor 35 Infrared radiation suppressor 36 Vehicle 37 Infrared radiation suppressor 38 Infrared radiation suppressor 39 Infrared radiation suppressor

Claims (10)

(57) [Claims] 1. A laminated film of a semiconductor layer and a dielectric layer, which transmit radio waves, is formed on the surface of a substrate. The laminated film has an infrared reflecting film portion for reflecting infrared light and a light of a specific wavelength of visible light. An infrared radiation suppressor comprising a visible light reflecting film portion that reflects light at a specific reflectance. 2. The infrared radiation suppressor according to claim 1, wherein the substrate is made of a dielectric material that transmits radio waves without absorbing them. 3. The infrared radiation suppressor according to claim 1, wherein said substrate is made of a radio wave absorber material. 4. The laminated film of the infrared reflecting film portion has a semiconductor layer having an optical thickness of λ / 4 made of a high refractive index material and an optical film thickness of λ made of a low refractive index material, where λ is the wavelength of infrared light to be reflected. The infrared radiation suppressor according to claim 1, wherein the infrared radiation suppressor is formed by alternately laminating a / 4 dielectric layer. 5. The optical film thickness of each layer of the laminated film in the infrared reflecting film portion is 3 to 5 μm wavelength and / or 8 to 13 μm.
5. The infrared radiator according to claim 4, wherein the infrared radiator is set for a wavelength of μm. 6. The visible light reflecting film portion according to claim 1, wherein a dielectric layer that reflects visible light of a specific wavelength is provided on a semiconductor layer that is opaque to visible light. Infrared radiation suppressor. 7. A radar dome for covering a radar apparatus, wherein the infrared radiation suppressor according to claim 2 is provided on at least the outer surface of the radar dome or in the vicinity thereof. 8. The radar dome according to claim 7, wherein a reflected light region composed of at least two kinds of camouflage colors is provided on a surface of said infrared radiation suppressor. 9. A moving object having a portion that emits infrared light and moving while emitting infrared light, wherein the infrared radiation suppressor according to claim 3 is provided on an outer surface of the portion that emits infrared light. Moving object. 10. The moving object according to claim 9, wherein a reflected light region composed of at least two types of camouflage colors is provided on a surface of the infrared radiation suppressor.