JPH03250797A - Laminated plate with low radio wave reflection property - Google Patents

Abstract

PURPOSE:To form a plate-shaped body with low reflectance for a radio wave such as a television broadcasting wave by dividing a diaphragm or a film into pieces each having the specific length on one side. CONSTITUTION:A diaphragm, a film or a plate-shaped body 2 is divided into pieces each having one side of a length equal to or below 0.4 times, preferably 0.3 times the wavelength lambda of a radio wave. When a plane wave is incident on a given scatterer, electrons only vibrate at a given point in tune with the frequency of an incident electromagnetic wave in the scatterer. The position of a portion with a high electron density generated by the vibration of electrons moves and this fact becomes a factor for reflecting the electromagnetic wave. A region wherein electrons can freely move is made smaller by reducing the ratio L/lambda by dividing the plate-shaped body 2 and, as a result, the reflecting quantity per unit area decreases. Thus, the reflectance for electromagnetic wave by a laminated plate is reduced and radio wave interference can be reduced as little as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a laminate that prevents interference with radio waves caused by buildings and the like and efficiently transmits radio waves.

[Prior Art] In recent years, ghost interference caused by reflection from buildings has become a problem when receiving television radio waves, and the provision of ferrite radio wave absorbers on the concrete walls of buildings is being put into practical use.

On the other hand, window glass is gradually becoming thicker, and
There is an increasing trend in the number of products that are coated with metal, metal oxide, etc. films, or are coated with films containing such films to provide functions such as heat insulation performance. The effect of thickness is not so great, but if you coat or attach a film that has a higher reflectivity for radio waves than glass, the reflectance will approach 100%, making radio interference unavoidable.

Therefore, in such cases, the windows in the direction in which the radio waves arrive had to be made of uncoated glass, which inevitably led to inconsistencies in the color tones of different buildings.

[Problems to be solved by the invention] The present invention has been made in view of the above points, and is
It is an object of the present invention to provide a plate-shaped body with reduced reflectance for radio waves such as V broadcast waves.

Means for Solving Problem E] The present invention provides a plate-like body in which a film or film having a higher reflectivity for radio waves than the substrate is formed on a substrate, and the film or film has a side length of It is characterized by being divided into 0.4 times or less the wavelength λ of the electromagnetic wave.

[Function] As a result of intensive research to reduce as much as possible radio wave interference caused by plate-like materials with high reflectivity for radio waves, such as insulating glass, the present inventors focused on dividing membranes or films and developed the present invention. This is what was done.

Af 2000 on a plate glass of 900fl square, ]0 Tsuru thickness
Prepare insulating glass with a reflectance of almost 100% that has been vapor-deposited to a thickness of about 100 mm, and cut it into square shapes with a canter or the like so that the side length L gradually decreases, each time having a length of 500 m.
The amount of reflection per unit area was measured when Hz radio waves were irradiated at an incident angle of 0 degrees.

Based on this result, the wavelength λ (50
When the relationship between the ratio L/λ and the amount of reflection was determined at 0 MHz, the results shown in FIG. 3 were obtained.

As is clear from this result, it can be seen that by setting L/λ to 0.4 or less, preferably 0.3 or less, the amount of reflection is significantly reduced.

It has been confirmed that a similar tendency exists throughout the TV broadcast wave VHF band with a frequency of 90 MIIz to the TV broadcast wave UHF band with a frequency of 770 M)lz.

This result is believed to be due to the following reasons.

That is, when a plane wave is incident on an arbitrary scatterer, a conductive current or a spacing current flows through the scatterer, which becomes a secondary radiation source, generates electromagnetic waves, and reflects the electromagnetic waves. In reality, the electrons do not move from one end of the scatterer to the other, but only oscillate at a certain point in tune with the frequency of the incident electromagnetic wave.

A region with high electron concentration generated by such electron vibration moves. This causes electromagnetic waves to be reflected. By dividing the plate-shaped body and reducing L/λ, the area in which electrons can move freely becomes narrower, and as a result, the amount of reflection per unit area decreases. It is estimated to be.

Furthermore, if the length of one side of the plate-shaped body is λ/2, a resonance phenomenon occurs and the electromagnetic wave is most efficiently received, so that a maximum value exists when L/λ is around 0.5. In the present invention, the amount of reflection is minimized by setting it to 0.4 or less, preferably 0.3 or less, which is even smaller than 0.5.

Further, when a conductive membrane or film having a thickness x (m) is irradiated with radio waves having a frequency of "2" in the vertical direction, the transmittance E of the radio waves becomes E=exp(-αX).

Here, α is the attenuation constant of the conductive film, and α=4.82π・
It is expressed as f+, so for example, if X is 500 people and f is 10
When 0Mt+z, the transmittance E is 0.93, which means that almost no absorption occurs, and the amount of reflection is also reduced by dividing, so it can be seen that radio waves are transmitted efficiently.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing a part of a laminate in Example 1 and Example 2 of the present invention, FIG. 2 is a perspective view showing a part of a laminate in Example 3 of the invention, and FIG. FIG. 3 is a characteristic diagram showing the relationship between L/λ and the amount of radio wave reflection per unit area.

An example will be described in which a plate glass is used as the substrate 1 and the plate glass is coated with a film 2 having heat insulating performance.

As shown in FIG.
Prepare a float glass with a concentration of 0 and 1, and apply a film 2 to this substrate 1.
First, cut slit 3 so that the length of one side is 150 cranes.
An organic dye is screen printed on the area where is formed, and after drying, stainless steel #
(S[l5316) as a target, about 10'3
A stainless steel film was formed to a thickness of 85 mm in argon gas at a reduced pressure of about 10 Torr, and then a titanium oxide film was formed to a thickness of 100 mm in an oxygen gas at a reduced pressure of about 10 Torr using titanium as a target. The zero-order organic dye formed into a film was removed.

In the thus obtained laminate, the length of one side of the membrane 2 is 1
50 cranes, the width of slit 3 is 1m, the color tone is silver gray, the visible light transmittance is 31%, and the visible light reflectance is 13%.
It showed good heat insulation performance with a solar transmittance of 25% and a solar reflectance of 11%.

Furthermore, 100Mt+z (L /λ-0,
05), 300MIlz (L/λ-0,15),
When the reflectance was measured by irradiating radio waves of 500M)lz (L/λ-0,25), the reflectance was 0.5% for each.
, 4%, and 11%. The reflectance when not divided is 18%, 15%, and 25%, respectively, which is significantly lower, and reduces radio wave interference for radio waves from the U to HF bands of TV broadcast waves. I understand.

An example in which a heat insulating film is attached to a substrate made of No. 11 Nine Shadow Glass will be described.

As shown in FIG.
Prepare 0 Tsuru float glass and set the sheet resistance to 50~
An organic film 2' on which Ag of 60Q/hole was vapor-deposited was pasted on almost the entire surface, and then the part corresponding to slit 3 was cut out with a sharp edge 1 crane using a cutter, etc., to form 36 pieces of film 2° each with a side length of 150 mW. Divide into squares.

The thus obtained laminate has a gold color, a visible light transmittance of 60%, a visible light reflectance of 21%, a solar transmittance of 44%, and a solar reflectance of 35%, and has good thermal insulation performance. In addition, 100M1lz (L/
λ-0,05), 300Hz (L/λ=0
．． 15) and 500 MIlz (L/λ-0,25) and measured the reflectance, and the reflectance was 0.5%, 12%, and 28%, respectively. The reflectance when not divided is 52%, 45%, and 63%, respectively, which is a significant decrease, and it is clear that radio wave interference is reduced for radio waves up to the UHF band of TV broadcast waves. Recognize. An example in which plate-like bodies are laminated using glass as a substrate will be described.

As shown in Figure 2, the board 1 is 9151 square and board thickness is 4.
Prepare a crane float glass, and add an interlayer film 4 such as polyvinyl butyral and a float glass 36 with a 150 u angle (L = 1501 mm) and a plate thickness of 611 mm as a plate-shaped body 2°.
After laminating the sheets so that the width of the slit 3 is 3N and temporarily press-bonding them, a normal autoclave treatment is performed to obtain a laminated sheet.

The laminate thus obtained has a frequency of 500 Mt (
For the radio wave of
Reduced to below.

Although the present invention has been described above using preferred embodiments, the present invention is not limited to these embodiments, and various applications are possible.

If the membrane or film laminated on the substrate of the present invention has a sheet resistance of IKQ10 or less, the effect can be expected, and therefore various known membranes or films can be used. In addition to plate glass, the plate-shaped body laminated on the substrate may be made of a construction material such as brass tink, ceramic, reinforced concrete, or a metal with high reflectance.

In addition, the length of each side of these varies depending on the frequency of the radio waves targeted for reflectance reduction.
~220Mtlz) up to 545fi,
Preferably it should be 409fi or less, and TV broadcast waves U
In the case of up to the HF band (470 MHz to 770 MHz), the substrate should be 1561 or less, preferably 117 u or less. In addition to glass, substrates that have a lower radio wave reflectance than the membrane, film, or plate-like material to be divided can be used. Various materials such as brass tink and mortar tiles can be used.

[Effects of the Invention] The laminate of the present invention divides a portion with a relatively high radio wave reflectance, and the length of one side thereof is set to 0.4 times or less, preferably 0.3 or less, to the radio wave wavelength λ. This reduces radio wave reflectance and minimizes radio wave interference.

Therefore, if a laminate of the present invention having heat-insulating performance is placed in the direction of arrival of radio waves in the windows of a building or other building, and a laminate of the same type that is not divided into other parts is placed, the whole building will be covered. In addition to having a heat insulating effect, they are also aesthetically pleasing because they can be made to have the same color tone.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a part of a laminate in Example 1 and Example 2 of the present invention, FIG. 2 is a perspective view showing a part of a laminate in Example 3 of the invention, and FIG. FIG. 3 is a characteristic diagram showing the relationship between L/λ and the amount of radio wave reflection per unit area. 1...Substrate 2...Membrane, 2''...Plate body 3...Surino 4...Intermediate film 2'

Claims (1)

[Claims] In a laminated plate in which a film, film, or plate-like body having a higher reflectivity for radio waves than the substrate is laminated on a substrate, the film, film, or plate-like body is laminated with a side length of 0.4 of the wavelength λ of the radio wave. A laminate having low reflection characteristics against radio waves, characterized in that it is divided into two parts or less.