JP2001284881A - Electromagnetic wave shield element and electromagnetic wave shield using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic wave shield element and an electromagnetic wave shield using the same which can reliably shield electromagnetic waves. SOLUTION: Many electromagnetic shields WS1-WSN are arranged in an window glass 1, and each electromagnetic shield WS1-WSN is composed of a pair of loop antennas for generating electromagnetic waves in mutually reverse phase. Especially a loop antenna having two loops formed like an 8-shape having a circumferential length equal to the wavelength of an electromagnetic wave to be shielded is bent to form an electromagnetic shield element having two parallel loops, thus simplifying the constitution. Matching units are attached to the pair of loop antennas and adjusted to shield electromagnetic waves at desired frequencies, and each loop antenna is fed with power to expand the receiving range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding element for shielding electromagnetic waves and an electromagnetic wave shielding body using the same.

[0002]

2. Description of the Related Art As a conventional electromagnetic wave shield, for example, one disclosed in Japanese Patent Application Laid-Open No. 10-126091 is known.

In this conventional example, a linear antenna element having a length resonating with a radio wave to be shielded is used as an electromagnetic shielding element, and an electromagnetic field reflection equivalent area (scattering aperture area) or an electromagnetic field reflection equivalent volume (electromagnetic field reflection equivalent volume) of the element is used. There is described a window glass having electromagnetic shielding performance in which the linear antenna elements are regularly arranged in consideration of a scattering aperture volume, and radio waves are scattered and attenuated by the linear antenna element.

[0004]

However, in the above-mentioned conventional example, electromagnetic waves are scattered by arranging the linear antenna elements on the glass surface or between the glass members. Considering the case of shielding electromagnetic waves, the equivalent electromagnetic field reflection area of each antenna element is 77.4 cm ² , and in order to cover a window glass having an area of 10,000 cm ² , 100 or more antenna elements are arranged. It is necessary and there is an unresolved problem that the view is obstructed, and since the antenna element resonates with the arriving electromagnetic wave, the electromagnetic wave radiated from the element acts as a radiation source. There is an unsolved problem that scattering is not always performed in a desired direction and a sufficient shielding effect cannot be expected.

Accordingly, the present invention has been made in view of the above-mentioned unsolved problems of the conventional example, and it is possible to suppress electromagnetic waves efficiently by suppressing them from being a radiation source of electromagnetic waves. It is an object of the present invention to provide an electromagnetic wave shielding element capable of expanding a reception range, and to provide an electromagnetic wave shielding body capable of sufficiently securing a field of view using the electromagnetic wave shielding element.

[0006]

In order to achieve the above object, an electromagnetic wave shielding element according to claim 1 has a pair of antenna elements that resonate with an electromagnetic wave to be shielded, and the pair of antenna elements has phases opposite to each other. Characterized in that the electromagnetic wave is generated.

According to the first aspect of the present invention, a pair of antenna elements resonating with the shielded electromagnetic wave to be shielded are provided, and these antenna elements are configured to generate electromagnetic waves having phases opposite to each other. One of the antenna elements receives an electromagnetic wave, and the other antenna element emits an electromagnetic wave having a phase opposite to that of the other antenna element, thereby canceling an electromagnetic field synthesized by the two and suppressing the emission of unnecessary electromagnetic waves.

The electromagnetic wave shielding element according to claim 2 is
In the invention according to claim 1, the antenna element is formed in an open end shape, the length thereof is set to １ ／ or less of the wavelength of the shielded electromagnetic wave, and a matching circuit is connected to the antenna element. , And resonates at the frequency of the shielded electromagnetic wave.

According to the second aspect of the present invention, by connecting a matching circuit to the antenna element, the impedance can be adjusted by the matching circuit and the electromagnetic wave to be shielded can be reliably resonated.

Further, in the electromagnetic wave shielding element according to claim 3, in the invention according to claim 1 or 2, the pair of antenna elements has two short loop portions having a circumference equal to the wavelength of the electromagnetic wave to be shielded. The eight-shaped loop antenna element is formed by connecting the eight-shaped loop antenna element with a straight portion, and the two loops are opposed to each other at a predetermined interval.

According to the third aspect of the present invention, it is possible to generate electromagnetic waves having phases opposite to each other in both loop portions by folding one 8-shaped loop antenna element and making the two loop portions face each other. In addition, the electromagnetic wave shielding element can be easily formed.

Further, in the electromagnetic wave shielding element according to a fourth aspect, in the invention according to any one of the first to third aspects, the pair of antenna elements directly supply power to one of the antenna elements from a power supply, and supply the other antenna element to the other. The antenna element is configured to be supplied with power from the power supply via an inverter.

According to the fourth aspect of the present invention, by supplying power to the pair of antenna elements from the power supply, the reception range of each antenna element is widened and one electromagnetic wave shielding element secures a wide electromagnetic wave shielding area. Can be.

According to a fifth aspect of the present invention, there is provided an electromagnetic wave shielding element, wherein the electromagnetic wave shielding element according to any one of the first to fourth aspects is a light-transmitting electromagnetic wave shielding element for shielding an electromagnetic wave to be shielded. The invention is characterized in that a predetermined number of a pair of antenna elements are arranged in a translucent substrate at predetermined intervals so as to be parallel to the front and back surfaces.

According to a fifth aspect of the present invention, the electromagnetic wave shielding element according to any one of the first to fourth aspects is arranged in a translucent substrate such that a pair of antenna elements are parallel to the front and back surfaces. Therefore, a light-transmitting substrate such as a window glass or a transparent flexible sheet in which emitted electromagnetic waves are suppressed can be formed.

According to a sixth aspect of the present invention, there is provided an electromagnetic wave shield comprising a light-transmitting electromagnetic wave shield for shielding an electromagnetic wave to be shielded, wherein the electromagnetic wave shield element according to any one of the first to fourth aspects is transparent. A predetermined number of antenna elements are arranged on the optical substrate at predetermined intervals so that a pair of antenna elements are located on the front and back surfaces thereof.

In the invention according to claim 6, since the pair of antenna elements are formed on both the front and back surfaces of the light-transmitting substrate, the manufacture is easier than in the case where the antenna elements are embedded.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing a first embodiment of the present invention, and FIG. 2 is an enlarged sectional view of FIG. 1. In the drawing, reference numeral 1 denotes a window glass as a light-transmitting substrate. A large number of electromagnetic wave shielding elements WS _{1 to} WS _N (N is a positive integer) are arranged within one at predetermined intervals.

Here, the electromagnetic wave shielding element WS₁ ~ WS_N of
As shown in FIG. 3, each of the
Magnetic waves (eg ISM (Industrial Scientific Medical)
Around the wavelength λ of a 2.4 GHz electromagnetic wave that forms a band)
Two substantially circular loop portions L each having a length and being partially open
P₁ And LP_Two And a short parallel connecting between these openings
Straight section SL₁ And SL_Two Figure 8 loop formed by
The antenna element LA is formed, and this 8-shaped loop antenna
As shown in FIG. 4, the element LA ₁ And L
P_Two And straight section SL₁ And SL_Two Bend at the connection with
The two loop parts LP₁ And LP_Two And a straight line
Section SL₁ And SL_Two Parallel to each other at a distance of
Loop parts LP having a configuration and facing each other₁ And LP_Two 
Form a pair of antenna elements.

Then, these electromagnetic wave shielding elements WS ₁ -W
_SN is provided in the window glass 1 with each of the electromagnetic wave shielding elements WS _{1 to} WS _N.
Are embedded at predetermined intervals so that a plane including the loop portions LP ₁ and LP ₂ is parallel to the front and back surfaces of the window glass 1. When the radiation pattern of the loop antenna is two-dimensionally shown in the YZ plane, it has a figure-eight shape as shown in FIG. 5, and when the radiation angle at this time is θ, the reception sensitivity becomes as shown in FIG. Since the angle θ becomes maximum at 0 degree and becomes minimum at 90 degrees or −90 degrees, the arrangement interval of each electromagnetic wave shielding element WS _{1 to} WS _N is adjusted so that the shielded electromagnetic wave does not pass through according to the reception sensitivity. Has been selected.

Next, the operation according to the first embodiment will be described.

[0023] Now, the window glass 1, as shown in FIG. 2, the loop portion LP ₁ of the electromagnetic wave shielding elements WS ₁ to WS _N and the outdoor side, and described as being arranged loop LP ₂ as an indoor side . When the electromagnetic waves to be shielded from the outside arrives, it will receive the electromagnetic waves outside the loop portion LP _1, since the circumferential length of the loop portion LP ₁ is equal to the wavelength of the electromagnetic wave lambda, resonance reception voltage E ₁ of a relatively large sinusoidal becomes is induced. The reception voltage E _1, it means that applied in opposite phases to the loop portion LP ₂ of the back side through the linear portion SL ₁ and SL _2, radiating electromagnetic waves of the electromagnetic waves in opposite phase received in the loop portion LP ₂ It will be, and cancel each other in the electromagnetic wave in the loop portion LP ₁ and the loop portion LP _2, as shown in FIG. 7, be greatly attenuated at the frequency f ₀ of the shield electromagnetic waves to be shielded received field As a result, transmission of electromagnetic waves to the indoor side can be efficiently prevented.

Here, the effective length (effective height) h _E representing the antenna radiation capability of the loop portions PL ₁ and PL ₂ is given by: h _E = 2πA / λ (1) where A is the area of the loop. Since the perimeter of each of the loop portions PL ₁ and PL ₂ is 1λ, the radius r is r = λ / π.
Since the area A is A = πr ² = λ ² / 4π, the above equation (1) is given by h _E = (2π / λ) · (λ ² / 4π) = λ / 2 (2) It is possible to obtain sufficient antenna radiation ability and shield electromagnetic waves.

[0025] Thus, according to the first embodiment has a loop portion LP ₁ and LP ₂ equal to the wavelength λ of the shielding electromagnetic waves perimeter attempts shielding, electromagnetic waves of at opposite phases since it is configured to generate, to offset the electromagnetic waves generated by the two loop portions LP ₁ and LP ₂ able to inhibit the synthesis field, it is possible to exert a greater electromagnetic shielding effect.

Further, since the electromagnetic wave shielding elements WS _{1 to} WS _N embedded in the window glass 1 are formed by bending the figure-eight loop antenna element LA, the structure is simplified and the manufacturing is facilitated. it can.

In the first embodiment, the case where the electromagnetic wave shielding elements WS _{1 to} WS _N are constituted by one loop antenna element LA has been described. However, the present invention is not limited to this. as shown, constituted by a loop antenna element LA ₁ and LA ₂ of the loop portion LP ₁ and LP ₂ equal to the wavelength λ of the shield electromagnetic waves are two parallel disposed each other is divided into two to be shielded, These may be connected via an inverter IN for inverting the phase of the induced power.
An 80-degree phase shifter IN can be applied.

Further, in the first embodiment has described the case of embedding the electromagnetic wave shielding element WS ₁ to WS _N on the window glass 1 is not limited thereto, a pair of loop LP ₁ and it may be the LP ₂ to be disposed in close contact to the front and back surfaces of the window pane 1, in this case, it is preferable to form the loop LP ₁ and LP ₂ by printed wiring. Further, one loop portion is disposed on the surface of the window glass 1 and the other loop portion is provided on the window glass 1.
It may be buried inside.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the second embodiment, the electromagnetic wave shielding element W
As S _{1 to} WS _N , a pair of loop antenna elements LA whose perimeter is smaller than the wavelength of the shielded electromagnetic wave to be shielded
₁ and LA ₂ are used to shield electromagnetic waves.

That is, in the second embodiment, FIG.
As shown in FIG. 9, a pair of loop antennas LA₁ And LA
_Two Whose perimeter is, for example, the
It is set to の of the wavelength λ of the shielding electromagnetic wave, and
Each loop antenna LA₁ And LA_Two A matcher AJ₁ Passing
And AJ_Two Is connected. Here, the loop antenna L
A₁ And LA_Two The frequency of the electromagnetic wave shielded by
Antenna LA₁ And LA _Two Circumference and matching device AJ₁ And A
J_Two Can be determined by the impedance of
Matching device AJ according to the frequency of the electromagnetic wave₁ And AJ_Two To
adjust.

_{One of the} matching devices AJ ₁ and AJ ₂ , for example, the matching device AJ ₁ is directly connected to the power supply circuit VC via the power supply line VL ₁ , and the other matching device AJ ₂ is connected to the power supply line VL ₂ And to the power supply circuit VC via an inverter IN. The power supply circuit VC has a reference antenna RA for detecting the state of the shielded electromagnetic wave to be shielded to the outside of the room, and generates power supply having an amplitude synchronized with the amplitude of the shielded electromagnetic wave detected by the reference antenna RA. To supply the power to the power supply line VL ₁
And outputs to the matching unit AJ ₁ via the inverter I
And it is configured to output to the matching unit AJ ₂ through N and the power supply line VL _2.

[0033] According to the second embodiment, the matching device AJ ₁ and AJ ₂ to the pair of loop antennas LA ₁ and LA ₂
Since is provided, by adjusting the matching device AJ ₁ and AJ _2, it becomes possible to block the electromagnetic waves of any frequency, the electromagnetic wave shielding elements WS ₁ to W-
By supplying power to the _SN from the power supply circuit VC, the reception sensitivity can be improved and the reception range can be expanded.
The arrangement interval of the electromagnetic wave shielding elements WS _{1 to} WS _N can be set longer than in the above-described first embodiment. For this reason, electromagnetic waves can be shielded without impairing the translucency of the window glass 1.

In the second embodiment as well, the loop antennas LA ₁ and LA ₂ can be formed on both the front and back surfaces of the window glass 1. In this case, the feed lines VL ₁ and VL ₁ connected to the feed circuit VC are provided. Since it is only necessary to form the VL ₂ on both the front and back surfaces of the window glass 1, there is an advantage that the manufacture becomes easy.

Further, in the first and second embodiments have been described as applied to circular loop antenna AL ₁ and AL _2, is not limited to this, a square, any such triangle A loop antenna having the following shape can be applied. Further, as shown in FIG.
A plurality of, for example, a loop antenna having a four loop LA ₁ ~LA ₄ may be caused to face the front and back.

Further, in the first and second embodiments, the case where the present invention is applied to the window glass 1 has been described. However, the present invention is not limited to this, and it is not limited to this. It can be applied to products for which transmission or emission of electromagnetic waves is desired to be suppressed, such as glass or personal computer screens.

Furthermore, in the first and the above embodiments, the case where glass is used as the light-transmitting substrate has been described. However, the present invention is not limited to this, and a light-transmitting synthetic resin sheet is used. You can also. Furthermore, a plurality of light-transmitting substrates having different frequencies of the electromagnetic waves that can be shielded by changing the perimeters of the electromagnetic wave shielding elements WS _{1 to} WS _N are stacked or arranged at predetermined intervals. Thereby, electromagnetic waves of different frequencies can be shielded.

[0038]

As described above, according to the first aspect of the present invention, a pair of antenna elements resonating with a shielded electromagnetic wave to be shielded are provided, and these antenna elements generate electromagnetic waves having phases opposite to each other. As a result, one antenna element receives an electromagnetic wave and the other antenna element emits an electromagnetic wave having a phase opposite to that of the other antenna element. Radiation is surely suppressed, and the effect of improving the electromagnetic wave shielding effect can be obtained.

According to the second aspect of the present invention, by connecting a matching circuit to the antenna element, the impedance can be adjusted by the matching circuit so that any electromagnetic wave to be shielded can be reliably resonated. The effect that it can be obtained is obtained.

Further, according to the invention of claim 3, 1
By bending the eight figure-shaped loop antenna elements and making the two loop portions face each other, it is possible to generate electromagnetic waves having phases opposite to each other in both loop portions. The effect that it can be easily formed is obtained.

Further, according to the fourth aspect of the present invention, by supplying power from a power supply to a pair of antenna elements, the reception range of each antenna element is widened, and one electromagnetic wave shielding element is used to cover a wide electromagnetic wave shielding area. And when applied to a light-transmitting substrate such as a window glass, the effect of suppressing a decrease in light-transmitting property can be obtained.

According to the fifth aspect of the present invention, the electromagnetic wave shielding element is arranged in the translucent substrate such that the pair of antenna elements are parallel to the front and back surfaces, so that the radiated electromagnetic wave can be reduced. The effect is obtained that a light-transmitting substrate such as a suppressed window glass or a transparent flexible sheet can be formed.

According to the sixth aspect of the present invention, since a pair of antenna elements are formed on both the front and back surfaces of the translucent substrate, there is an effect that the manufacture is easier as compared with the case where the antenna elements are embedded. can get.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of FIG.

FIG. 3 is a front view showing a loop antenna LA for forming an electromagnetic wave shielding element.

FIG. 4 is a perspective view showing an electromagnetic wave shielding element formed by bending the loop antenna of FIG. 3;

FIG. 5 is an explanatory diagram illustrating reception characteristics of a loop antenna.

FIG. 6 is a characteristic diagram showing reception sensitivity characteristics of the electromagnetic wave shielding element.

FIG. 7 is a characteristic diagram showing a reception electric field characteristic of the electromagnetic wave shielding element.

FIG. 8 is an enlarged sectional view similar to FIG. 2, showing a modification of the first embodiment.

FIG. 9 is a sectional view showing a second embodiment of the present invention.

FIG. 10 is a front view showing a modification of the electromagnetic wave shielding element.

[Explanation of symbols]

1 glazing WS ₁ to WS _N electromagnetic shielding element LA loop antenna LP _1, LP ₂ loop portion SL _1, SL ₂ linear portion LA _1, LA ₂ loop antenna IN inverter AJ _1, AJ ₂ matcher VL _1, VL ₂ feed Electric wire VC power supply circuit

Claims (6)

[Claims] 1. An electromagnetic wave shielding element comprising a pair of antenna elements resonating with a shielded electromagnetic wave, wherein the pair of antenna elements are configured to generate electromagnetic waves having phases opposite to each other. 2. The antenna element is formed in an open end shape, the length thereof is set to be equal to or less than half the wavelength of the electromagnetic wave to be shielded, and the antenna element is shielded by connecting a matching circuit to the antenna element. The electromagnetic wave shielding element according to claim 1, wherein the element is resonated at a frequency of the electromagnetic wave. 3. The pair of antenna elements is formed by connecting two loop parts having a perimeter equal to the wavelength of the electromagnetic wave to be shielded by a short straight part to form an 8-shaped loop antenna element.
3. The electromagnetic wave shielding element according to claim 1, wherein the eight-shaped loop antenna is formed by bending the loop at a straight portion so that both loops are opposed to each other with a predetermined interval. 4. The pair of antenna elements are configured to directly supply power to one antenna element from a power supply and to supply power to the other antenna element from the power supply via an inverter. The electromagnetic wave shielding element according to claim 1. 5. A translucent electromagnetic wave shield configured to shield an electromagnetic wave to be shielded, wherein the electromagnetic wave shielding element according to claim 1 includes a pair of antenna elements in a translucent substrate. An electromagnetic wave shield, wherein a predetermined number is arranged at predetermined intervals so as to be parallel to the front and back surfaces. 6. A light-transmitting electromagnetic wave shield for shielding an electromagnetic wave to be shielded, wherein the electromagnetic wave shielding element according to claim 1 is provided on a light-transmitting substrate with a pair of front and rear surfaces. An electromagnetic wave shield, wherein a predetermined number of antenna elements are arranged at predetermined intervals so as to be positioned.