TW202322686A - Electromagnetic wave reflection sheet, roll body, method for manufacturing electromagnetic wave reflection sheet, and communication system - Google Patents

Abstract

An electromagnetic wave reflection sheet (1) comprises a substrate (2) and an electromagnetic wave reflection layer (3) sequentially toward one side in the thickness direction. The electromagnetic wave reflection sheet (1) has a transmittance of 83% or more with respect to light having a wavelength of 550 nm. The electromagnetic wave reflection sheet (1) has a shielding effect of 9 dB or more with respect to an electromagnetic wave having a frequency of 28 GHz. The electromagnetic wave reflection sheet (1) has a thickness T of 50-400 [mu]m.

Description

Electromagnetic wave reflecting sheet, roll body, manufacturing method of electromagnetic wave reflecting sheet, and communication system

The invention relates to an electromagnetic wave reflecting sheet, a roller body, a manufacturing method of the electromagnetic wave reflecting sheet and a communication system.

An electromagnetic wave reflective sheet that reflects electromagnetic waves including signals in the millimeter wave band is known. For example, an electromagnetic wave reflection sheet made of aluminum foil has been proposed (for example, refer to the following patent document 1). The electromagnetic wave reflecting sheet described in Patent Document 1 is arranged on a wall surface. The wall surface is endowed with reflectivity to electromagnetic waves. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2000-165959

[Problem to be solved by the invention]

According to the use and purpose, it is required to effectively utilize the design of the wall surface. In addition, when the wall includes glass, it is also required to secure the permeability of the wall. However, the reflective sheet described in Patent Document 1 may not meet the above requirements because of its low transmittance of visible light.

In addition, reliability and operability are required for electromagnetic wave reflecting sheets.

Furthermore, electromagnetic wave reflective sheets are required to have higher reflectivity to electromagnetic waves.

The present invention provides an electromagnetic wave reflective sheet, a roll body, a manufacturing method of an electromagnetic wave reflective sheet, and a communication system that can effectively utilize the design of the arrangement object, have excellent reliability and operability, and have excellent reflectivity to electromagnetic waves. [Technical means to solve the problem]

The present invention (1) includes an electromagnetic wave reflective sheet, which is sequentially provided with a base material and an electromagnetic wave reflective layer facing one side in the thickness direction, and has a transmittance of 83% or more for light with a wavelength of 550 nm, and an electromagnetic wave with a frequency of 28 GHz. The shielding effect is above 9 dB, and the thickness is above 50 μm and below 400 μm.

The transmittance of the electromagnetic wave reflective sheet to light with a wavelength of 550 nm is as high as 83%. Therefore, the design of the allocation object can be effectively utilized. Also, when the object includes a transparent material, the transparency of the laminated portion of the object and the electromagnetic wave reflecting sheet can be ensured.

The electromagnetic wave reflective sheet has a shielding effect of more than 9 dB on electromagnetic waves with a frequency of 28 GHz. Therefore, the electromagnetic wave reflective sheet has excellent reflectivity to electromagnetic waves.

The thickness of the electromagnetic wave reflecting sheet is more than 50 μm, so it is excellent in reliability. The thickness of the electromagnetic wave reflecting sheet is 400 μm or less, so it is excellent in handling.

The present invention (2) includes the electromagnetic wave reflecting sheet as described in (1), further comprising an adhesive layer, and the adhesive layer forms one or the other surface of the electromagnetic wave reflecting sheet in the thickness direction.

The present invention (3) includes the electromagnetic wave reflecting sheet as described in (1) or (2), which forms one surface in the thickness direction of the above-mentioned electromagnetic wave reflecting sheet, and the above-mentioned bases are sequentially arranged toward one side in the thickness direction. material, the above-mentioned electromagnetic wave reflective layer and the above-mentioned adhesive layer.

The present invention (4) includes the electromagnetic wave reflecting sheet described in any one of (1) to (3), further comprising a protective layer in contact with one surface in the thickness direction of the electromagnetic wave reflecting layer.

The electromagnetic wave reflective sheet has a protective layer, so the mechanical strength of the electromagnetic wave reflective sheet is improved, thereby preventing damage to the electromagnetic wave reflective layer.

The present invention (5) includes the electromagnetic wave reflective sheet described in (4), wherein the refractive index of the protective layer is not less than 1.4 and not more than 1.6, and the thickness of the protective layer is not less than 40 nm and not more than 250 nm.

The present invention (6) includes the electromagnetic wave reflecting sheet described in any one of (1) to (5), wherein the electromagnetic wave reflecting layer includes an inorganic oxide layer.

The present invention (7) includes a roll body formed by winding the electromagnetic wave reflection sheet described in any one of (1) to (6).

The present invention (8) includes the roll body described in (7), wherein the diameter of the inner dimension is 40 mm or more.

The present invention (9) includes the roll body described in (7) or (8), which does not have a winding core in its center.

The present invention (10) includes a method of manufacturing an electromagnetic wave reflective sheet, which includes the following steps: winding the electromagnetic wave reflective sheet described in any one of (1) to (6) to produce a roll body; The above-mentioned electromagnetic wave reflective sheet is rolled out; and the difference between the above-mentioned shielding effect of the above-mentioned electromagnetic wave reflective sheet before winding and the above-mentioned shielding effect of the above-mentioned electromagnetic wave reflective sheet rolled out from the above-mentioned roll body is 4.0 dB or less.

The present invention (11) includes a communication system comprising a transmitter, a receiver, and an electromagnetic wave reflecting sheet as described in any one of (1) to (6), and having a communication system for the electromagnetic waves emitted from the transmitter to pass through the above-mentioned After being reflected by the electromagnetic wave reflective sheet, it reaches the communication path of the above-mentioned receiver.

The present invention (12) includes a communication system including a transmitter, a receiver, a first electromagnetic wave reflecting sheet, and a second electromagnetic wave reflecting sheet, and the first electromagnetic wave reflecting sheet and the second electromagnetic wave reflecting sheet are respectively As the electromagnetic wave reflecting sheet described in any one of (1) to (6), the above-mentioned communication system is provided with the electromagnetic wave emitted from the above-mentioned transmitter passing through the above-mentioned first electromagnetic wave reflecting sheet and the above-mentioned second electromagnetic wave reflecting sheet in sequence After reflection, it reaches the communication path of the above receiver. [Effect of Invention]

The electromagnetic wave reflecting sheet, roll body, and communication system obtained by the method of manufacturing the electromagnetic wave reflecting sheet of the present invention can effectively utilize the design of the arrangement object, have excellent strength and operability, and have excellent reflectivity to electromagnetic waves.

1. Electromagnetic wave reflective sheet One embodiment of the electromagnetic wave reflecting sheet of the present invention will be described with reference to FIG. 1 . The electromagnetic wave reflecting sheet 1 extends in the plane direction. The plane direction is perpendicular to the thickness direction.

1.1 Transmittance of light with a wavelength of 550 nm The transmittance of the electromagnetic wave reflective sheet 1 to light with a wavelength of 550 nm is above 83%.

On the other hand, if the transmittance of the electromagnetic wave reflective sheet 1 to light with a wavelength of 550 nm is less than 83%, the visibility of the object 9 (refer to FIG. 2 ) on which the electromagnetic wave reflective sheet 1 is disposed will decrease, and the object 9 cannot be effectively used. The design. Furthermore, when the object 9 contains a transparent material such as glass, the transparency of the object 9 and the electromagnetic wave reflection sheet 1 cannot be ensured.

On the other hand, in this embodiment, since the transmittance of the electromagnetic wave reflective sheet 1 to light with a wavelength of 550 nm is 83% or more, the object 9 on which the electromagnetic wave reflective sheet 1 is disposed can be easily and reliably recognized, thereby enabling Effective use of object 9 design. Furthermore, when the object 9 contains a transparent material such as glass, the transparency of the laminated portion of the object 9 and the electromagnetic wave reflecting sheet 1 can be ensured.

The transmittance of the electromagnetic wave reflective sheet 1 to light with a wavelength of 550 nm is preferably at least 84%, more preferably at least 85%, and even more preferably at least 86%. The upper limit of the transmittance of the electromagnetic wave reflective sheet 1 to light with a wavelength of 550 nm is not limited. The upper limit of the transmittance of the electromagnetic wave reflective sheet 1 to light having a wavelength of 550 nm is, for example, 100%, or, for example, 98%.

The transmittance of the electromagnetic wave reflective sheet 1 to light with a wavelength of 550 nm was measured using an integrating sphere spectroscopic transmittance measuring device.

1.2 Shielding effect on electromagnetic waves with a frequency of 28 GHz The shielding effect of the electromagnetic wave reflecting sheet 1 on electromagnetic waves with a frequency of 28 GHz is above 9 dB.

On the other hand, if the shielding effect of the electromagnetic wave reflection sheet 1 on the electromagnetic wave with a frequency of 28 GHz is less than 9 dB, the reflectivity to the electromagnetic wave is not sufficient.

On the other hand, in this embodiment, since the shielding effect of the electromagnetic wave reflecting sheet 1 on electromagnetic waves with a frequency of 28 GHz is 9 dB or more, the electromagnetic wave reflecting sheet 1 has excellent reflectivity to electromagnetic waves.

The shielding effect of the electromagnetic wave reflecting sheet 1 on electromagnetic waves with a frequency of 28 GHz is preferably at least 13 dB, more preferably at least 15 dB. Also, the upper limit of the shielding effect of the electromagnetic wave reflection sheet 1 on electromagnetic waves with a frequency of 28 GHz is, for example, 30 dB, and is, for example, 28 dB.

The higher the shielding effect of the electromagnetic wave reflecting sheet 1 is, the better the electromagnetic wave reflectivity of the electromagnetic wave reflecting sheet 1 is.

The shielding effect on electromagnetic waves with a frequency of 28 GHz is measured by the free space method.

In the free space method, for example, a measuring device 11 shown in FIG. 5 is used. The measuring device 11 includes a transmitting antenna 12 , a receiving antenna 13 , and a network analyzer 14 . The receiving antenna 13 is arranged opposite to the transmitting antenna 12 with a gap therebetween. The network analyzer 14 is connected to the transmitting antenna 12 and the receiving antenna 13 .

In the free space method, first, an electromagnetic wave with a frequency of 28 GHz is transmitted from the transmitting antenna 12 to the receiving antenna 13 . The receiving antenna 13 receives the electromagnetic wave, and the network analyzer 14 detects the voltage V0.

Next, the electromagnetic wave reflecting sheet 1 is arranged between the transmitting antenna 12 and the receiving antenna 13 . Then, electromagnetic waves with a frequency of 28 GHz are transmitted from the transmitting antenna 12 to the receiving antenna 13 . At this time, the electromagnetic wave reflecting sheet 1 reflects and blocks a part of electromagnetic waves. Then, the receiving antenna 13 receives the remaining part of the electromagnetic wave, and the network analyzer 14 detects the voltage V1.

The shielding effect SE was obtained by the following formula. SE[dB]＝-20log｜V1/V0｜

The shielding effect of the electromagnetic wave reflective sheet 1 on electromagnetic waves with a frequency of 28 GHz is adjusted to the above range by changing the thickness and/or electron carrier density of the electromagnetic wave reflective layer 3 . In addition, the said adjustment of the electromagnetic wave reflection sheet 1 is not limited to the said content.

1.3 Thickness T of the electromagnetic wave reflective sheet 1 The thickness T of the electromagnetic wave reflecting sheet 1 is not less than 50 μm and not more than 400 μm. Furthermore, the thickness T of the electromagnetic wave reflecting sheet 1 is the total thickness of the base material 2 , the electromagnetic wave reflecting layer 3 and the adhesive layer 4 described below.

On the other hand, when the thickness T of the electromagnetic wave reflecting sheet 1 is less than 50 μm, the reliability of the electromagnetic wave reflecting sheet 1 decreases. For example, when a construction worker manually winds the electromagnetic wave reflecting sheet 1 to form the roll body 7 , the electromagnetic wave reflecting layer 3 may be damaged due to insufficient strength or bending. Damage includes cracks. Therefore, the electromagnetic wave reflectivity of the electromagnetic wave reflective sheet 1 falls.

On the other hand, in this embodiment, since the thickness T of the electromagnetic wave reflecting sheet 1 is 50 μm or more, the reliability of the electromagnetic wave reflecting sheet 1 is excellent. For example, even if a construction worker winds up the electromagnetic wave reflecting sheet 1 manually to form the roll body 7, the above damage to the electromagnetic wave reflecting layer 3 can be suppressed because it has sufficient strength and rigidity. Therefore, the fall of the electromagnetic wave reflectivity of the electromagnetic wave reflective sheet 1 can be suppressed. Furthermore, when the electromagnetic wave reflecting sheet 1 is being constructed, it is necessary to cut out the required area and manually form the roll body 7 by the construction worker. The curvature becomes larger, and it is easy to cause damage. According to the present invention, by setting the thickness of the electromagnetic wave reflecting sheet 1 in an appropriate range (preferably 50 μm or more), damage can be suppressed even if it is wound up manually.

The thickness T of the electromagnetic wave reflecting sheet 1 is preferably at least 100 μm, more preferably at least 125 μm.

Moreover, when the thickness T of the electromagnetic wave reflecting sheet 1 exceeds 400 μm, the rigidity of the electromagnetic wave reflecting sheet 1 becomes too high, and the handleability decreases. For example, when the electromagnetic wave reflecting sheet 1 is wound to manufacture the roll body 7 , the electromagnetic wave reflecting sheet 1 cannot be smoothly wound due to excessive rigidity of the electromagnetic wave reflecting sheet 1 . If the thickness T of the electromagnetic wave reflective sheet 1 exceeds 400 μm, when the construction operator manually makes a small-diameter roll body 7 that can be grasped during construction, especially when there is no winding core, the thickness of the electromagnetic wave reflective sheet 1 Excessive rigidity can make winding difficult.

On the other hand, in this embodiment, since the thickness T of the electromagnetic wave reflecting sheet 1 is 400 μm or less, the rigidity of the electromagnetic wave reflecting sheet 1 can be suppressed from becoming too high, and the handleability is excellent. For example, when the electromagnetic wave reflecting sheet 1 is wound to manufacture the roll body 7 , the electromagnetic wave reflecting sheet 1 can be wound smoothly because the electromagnetic wave reflecting sheet 1 has a moderate rigidity. In this embodiment, since the thickness T of the electromagnetic wave reflecting sheet 1 is 400 μm or less, when the construction operator manually makes the roll body 7 with a small diameter that can be grasped, especially when there is no winding core , because the rigidity of the electromagnetic wave reflecting sheet 1 is moderate, it can be wound.

The thickness T of the electromagnetic wave reflecting sheet 1 is preferably not more than 375 μm, more preferably not more than 225 μm.

1.4 Layer Composition of Electromagnetic Wave Reflecting Sheet 1 As shown in FIG. 1 , the electromagnetic wave reflecting sheet 1 includes a substrate 2 , an electromagnetic wave reflecting layer 3 , and an adhesive layer 4 in this order toward one side in the thickness direction. In the electromagnetic wave reflective sheet 1 , a substrate 2 , an electromagnetic wave reflective layer 3 , and an adhesive layer 4 are sequentially disposed toward one side in the thickness direction. In this embodiment, the electromagnetic wave reflection sheet 1 includes only the base material 2 , the electromagnetic wave reflection layer 3 , and the adhesive layer 4 . In this embodiment, the adhesive layer 4 is arranged on the opposite side of the base material 2 with respect to the electromagnetic wave reflection layer 3 . During the construction operation, the adhesive in the adhesive layer 4 plays a buffering role, and the electromagnetic wave reflection layer 3 is not exposed to the outermost surface after the construction operation, and the electromagnetic wave reflection layer 3 is covered by the base material 2 . Therefore, damage to the electromagnetic wave reflection layer 3 caused by physical contact or the like can be reduced.

1.4.1 Substrate 2 In this embodiment, the base material 2 forms the other surface in the thickness direction of the electromagnetic wave reflection sheet 1 . The base material 2 extends in the surface direction. The substrate 2 is in the form of a sheet. The base material 2 supports the electromagnetic wave reflection layer 3 from the other side in the thickness direction. The base material 2 has flexibility. As a material of the base material 2, a polymer material is mentioned, for example. As a polymer material, resin is mentioned, for example. Examples of resins include polyester resins, olefin resins, acrylic resins, polycarbonate resins, polyether resins, polyarylate resins, melamine resins, polyamide resins, polyimide resins, and cellulose resins. and polystyrene resin. As a polyester resin, polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate are mentioned, for example. As an olefin resin, polyethylene, a polypropylene, and cycloolefin polymer (COP) are mentioned, for example. As the resin, PET and COP are preferable from the viewpoint of transparency, flexibility, and mechanical properties.

The transmittance of the substrate 2 to light with a wavelength of 550 nm is, for example, 90% or higher, preferably 92% or higher, more preferably 95% or higher, and for example, 98% or lower. Since the transmittance of the substrate 2 to light having a wavelength of 550 nm is above the above lower limit, the substrate 2 is called a transparent substrate 2 .

The thickness of the substrate 2 is, for example, 25 μm or more, preferably 50 μm or more, and for example, 350 μm or less, preferably 200 μm or less.

The ratio of the thickness of the substrate 2 to the thickness of the electromagnetic wave reflecting sheet 1 is, for example, 0.5 or more, preferably 0.7 or more, and for example, 0.9 or less, preferably 0.85 or less.

1.4.2 Electromagnetic wave reflection layer 3 The electromagnetic wave reflection layer 3 extends in the surface direction. The electromagnetic wave reflection layer 3 is disposed on one surface of the substrate 2 in the thickness direction.

In this embodiment, the electromagnetic wave reflection layer 3 includes an inorganic oxide layer. In this embodiment, the inorganic oxide layer is one layer. As the material of the inorganic oxide layer, for example, one selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W can be exemplified. At least one kind of inorganic oxide. Examples of inorganic oxides include indium zinc composite oxide (IZO), indium gallium zinc composite oxide (IGZO), indium gallium composite oxide (IGO), indium tin composite oxide (ITO), antimony tin composite oxide substance (ATO). From the viewpoint of transparency and electromagnetic wave reflectivity, ITO may be mentioned.

The electromagnetic wave reflection layer 3 is crystalline or amorphous.

As shown in FIG. 1 , the electromagnetic wave reflection layer 3 may be arranged on the entire surface of the substrate 2 in the thickness direction, or may be arranged on a part of one surface of the substrate 2 in the thickness direction. When the electromagnetic wave reflection layer 3 is arranged on a part of one surface in the thickness direction of the base material 2, it is formed in a pattern. As a pattern, the shape of FSS (Frequency selective surface, frequency selective surface) can be mentioned, for example.

The thickness of the electromagnetic wave reflecting layer 3 is, for example, more than 25 nm, preferably more than 30 nm, and for example, less than 160 nm, preferably less than 130 nm.

The ratio of the thickness of the electromagnetic wave reflecting layer 3 to the thickness of the electromagnetic wave reflecting sheet 1 is, for example, 0.00005 or more, preferably 0.0001 or more, and for example, 0.0006 or less, preferably 0.004 or less. The ratio of the thickness of the electromagnetic wave reflecting layer 3 to the thickness of the substrate 2 is, for example, 0.00006 or more, preferably 0.00015 or more, and for example, 0.0064 or less, preferably 0.0026 or less.

1.4.3 Adhesive layer 4 In this embodiment, the adhesive layer 4 forms one surface in the thickness direction of the electromagnetic wave reflection sheet 1 . The adhesive layer 4 is located on the opposite side of the base material 2 relative to the electromagnetic wave reflection layer 3 in the thickness direction. The adhesive layer 4 is disposed on one surface of the electromagnetic wave reflection layer 3 in the thickness direction. The adhesive layer 4 is in contact with one surface in the thickness direction of the electromagnetic wave reflection layer 3 .

The material of the adhesive layer 4 is not limited. As a material, an acrylic adhesive composition, a silicone adhesive composition, a urethane adhesive composition, for example, a rubber adhesive composition is mentioned, for example. From the viewpoint of transparency and durability, an acrylic adhesive composition is preferable.

The thickness of the adhesive layer 4 is, for example, 15 μm or more, preferably 25 μm or more, more preferably 50 μm or more, and for example, 100 μm or less, preferably 75 μm or less.

1.5 Manufacturing method and use of electromagnetic wave reflecting sheet 1 (disposition to object) The manufacturing method of the electromagnetic wave reflection sheet 1 is provided with the 1st process, the 2nd process, and the 3rd process, for example. In this embodiment, each of the first step and the second step is implemented by the roll-to-roll method.

1.5.1 The first step In the first step, the substrate 2 is prepared. For example, a long substrate 2 is prepared as the roll body 7 .

1.5.2 The second step In the second step, the electromagnetic wave reflection layer 3 is formed on one surface of the substrate 2 in the thickness direction. As a formation method of the electromagnetic wave reflection layer 3, a vacuum evaporation method, a sputtering method, and an ion plating method are mentioned, for example. Preferable one may, for example, be a sputtering method. As a sputtering method, the magnetron sputtering method is mentioned, for example. The method of forming the electromagnetic wave reflecting layer 3 is described in, for example, Japanese Patent Laid-Open No. 2020-149876 and Japanese Patent Laid-Open No. 2020-144116. The conditions for forming the electromagnetic wave reflection layer 3 are not limited.

Thereafter, the electromagnetic wave reflection layer 3 is patterned as necessary.

1.5.3 Step 3 In the third step, the adhesive layer 4 is disposed on one surface of the electromagnetic wave reflection layer 3 . For example, the adhesive layer 4 formed on the release sheet not shown is transferred to one surface of the electromagnetic wave reflection layer 3 . Alternatively, a varnish of the adhesive composition may be applied to one surface of the electromagnetic wave reflection layer 3 and dried.

By implementing the third step, the electromagnetic wave reflection sheet 1 provided with the base material 2 , the electromagnetic wave reflection layer 3 , and the adhesive layer 4 is wound into a roll body 7 .

The diameter R of the inner dimension of the roller body 7 is, for example, 25 mm or more, preferably 40 mm or more, more preferably 75 mm or more, further preferably 150 mm or more, and for example, 1,000 mm or less. When the diameter R of the internal dimension of the roll body 7 is more than the said minimum, it can suppress that the electromagnetic wave reflection sheet 1 after unwinding is curled. The roll body 7 can be downsized as the diameter R of the internal dimension of the roll body 7 is below the said upper limit.

In this embodiment, even if the roll body 7 does not have a winding core in the center, it can be manually formed into a small-diameter roll body 7 by a construction worker without causing damage.

1.6 Configuration of electromagnetic wave reflective sheet 1 In order to arrange the electromagnetic wave reflecting sheet 1 on the object 9 , first, the electromagnetic wave reflecting sheet 1 is unwound from the above-mentioned roll body 7 . Then, the electromagnetic wave reflecting sheet 1 is processed into a specific size and shape.

As shown in FIG. 2 , the electromagnetic wave reflecting sheet 1 is placed on the object 9 . The object 9 has a surface 10 . Specifically, the electromagnetic wave reflection sheet 1 is bonded to the surface 10 . Specifically, the adhesive layer 4 of the electromagnetic wave reflecting sheet 1 is bonded (pressure-sensitively bonded) to the surface 10 .

Examples of the object 9 include walls, glass windows, pillars, ceilings, partitions, screens, desks, and electronic devices of buildings. As an electronic device, a TV and a notebook computer are mentioned, for example.

By arranging the electromagnetic wave reflective sheet 1 on the object 9 , electromagnetic wave reflectivity is imparted to the surface 10 of the object 9 . Examples of the reflected electromagnetic waves include microwaves, millimeter waves, and megahertz waves. The frequency of the electromagnetic wave is, for example, above 1 GHz, preferably above 5 GHz, more preferably above 10 GHz, further preferably above 15 GHz, especially preferably above 20 GHz, most preferably above 25 GHz, and for example 1 THz the following. If the frequency of the electromagnetic wave is above 5 GHz, a frequency band with less noise can be used, which is suitable for high-speed communication.

Also, the difference between the shielding effect of the electromagnetic wave reflective sheet 1 before being wound into the roll body 7 and the shielding effect of the electromagnetic wave reflective sheet 1 rolled out from the roll body 7 is, for example, 4.0 dB or less, preferably 3.0 dB or less, more preferably The best is below 2.0 dB. The lower limit of the above-mentioned difference is not limited. The lower limit of the difference is, for example, 0.0 dB, or, for example, 0.1 dB. When the difference is not more than the above upper limit, the reliability of the roller body 7 can be improved.

2. The effect of an implementation The transmittance of the electromagnetic wave reflective sheet 1 to light with a wavelength of 550 nm is as high as 83% or more. Therefore, the design of the object 9 can be effectively utilized. Furthermore, when the object 9 is a glass window, the transparency of the laminated portion of the object 9 and the electromagnetic wave reflecting sheet 1 can be ensured.

The shielding effect of the electromagnetic wave reflecting sheet 1 on electromagnetic waves with a frequency of 28 GHz is above 9 dB. Therefore, the electromagnetic wave reflecting sheet 1 has excellent reflectivity to electromagnetic waves.

Since the thickness T of the electromagnetic wave reflecting sheet 1 is 50 μm or more, it is excellent in reliability. For example, even if the roll body 7 is manufactured by winding the electromagnetic wave reflection sheet 1 , and then the electromagnetic wave reflection sheet 1 is unwound from the roll body 7 , the decrease in the electromagnetic wave reflectivity of the electromagnetic wave reflection sheet 1 can be suppressed.

Since the thickness T of the electromagnetic wave reflecting sheet 1 is 400 μm or less, the rigidity of the electromagnetic wave reflecting sheet 1 can be suppressed from becoming too high, and the handleability is excellent. For example, when the roll body 7 is produced by winding the electromagnetic wave reflecting sheet 1 , the electromagnetic wave reflecting sheet 1 can be wound smoothly.

Moreover, since this electromagnetic wave reflecting sheet 1 is equipped with the adhesive agent layer 4, the electromagnetic wave reflecting sheet 1 can be attached to the object 9 reliably.

Since the difference in the shielding effect of the electromagnetic wave reflecting sheet 1 before being wound onto the roll body 7 and after being unwound from the roll body 7 is 4.0 dB or less, the reliability of the roll body 7 can be improved.

In addition, even if the roll body 7 does not have a winding core, it can be manually formed into a small-diameter roll body 7 by a construction worker without causing damage. Therefore, after the step of unwinding the electromagnetic wave reflecting sheet 1, when the small-diameter roll body 7 is rewound for construction work, the winding core does not remain. As a result, environmental load can be reduced.

3. Variations In the modified example, the same reference symbols are assigned to the same components and steps as those in the first embodiment, and detailed descriptions thereof are omitted. In addition, the modified examples can exhibit the same operational effects as those of the first embodiment, unless otherwise specified. Furthermore, one embodiment and its modifications can be combined appropriately.

3.1 The first variation example As shown in FIG. 4 , the electromagnetic wave reflection sheet 1 may further include a protective layer 5 . In the electromagnetic wave reflective sheet 1 of the second modification, the substrate 2 , the electromagnetic wave reflective layer 3 , and the protective layer 5 are sequentially arranged toward one side in the thickness direction. The protective layer 5 is located on the opposite side of the base material 2 with respect to the electromagnetic wave reflection layer 3 in the thickness direction. The protective layer 5 is disposed on one surface in the thickness direction of the electromagnetic wave reflection layer 3 . The protective layer 5 is in contact with one surface in the thickness direction of the electromagnetic wave reflection layer 3 .

The refractive index of the protective layer 5 is, for example, 1.3 or more, preferably 1.4 or more, and for example, 1.7 or less, preferably 1.6 or less. When the refractive index of the protective layer 5 is within the above range, the visual recognition of the boundary between the patterned electromagnetic wave reflective layer 3 and the surrounding substrate 2 can be suppressed, and as a result, the appearance of the electromagnetic wave reflective sheet 1 is excellent. Since the above function is called optical adjustment, the protective layer 5 is called an optical adjustment layer.

The thickness of the protective layer 5 is, for example, 25 nm or more, preferably 40 nm or more, and for example, 500 nm or less, preferably 250 nm or less. The ratio of the thickness of the protective layer 5 to the thickness of the electromagnetic wave reflection layer 3 is, for example, 0.3 or more, preferably 1.3 or more, and for example, 8.3 or less, preferably 1.7 or less.

As the protective layer 5, a resin layer is mentioned, for example. As a material of a resin layer, a silicone resin, an epoxy resin, and a urethane resin are mentioned, for example. The material contains UV (Ultraviolet, ultraviolet) hardening resin. The resin layer is described in, for example, JP-A-2017-053038.

Since the electromagnetic wave reflective sheet 1 of the first modification further includes the protective layer 5 , the mechanical strength of the electromagnetic wave reflective sheet 1 is improved, thereby suppressing damage to the electromagnetic wave reflective layer 3 . Damage includes cracks.

3.2 The second variation example As shown by the phantom lines in FIG. 4 , the electromagnetic wave reflective sheet 1 includes a substrate 2 , an electromagnetic wave reflective layer 3 , a protective layer 5 and an adhesive layer 4 in order toward one side in the thickness direction. The thickness T of the electromagnetic wave reflective sheet 1 is the total thickness of the base material 2 , the electromagnetic wave reflective layer 3 , the protective layer 5 and the adhesive layer 4 .

3.3 The third variation example As shown in FIG. 3 , the adhesive layer 4 is disposed on the other side of the substrate 2 in the thickness direction. The electromagnetic wave reflection sheet 1 of the third modification includes an adhesive layer 4 , a base material 2 , and an electromagnetic wave reflection layer 3 in this order toward one side in the thickness direction.

Comparing one embodiment with the third modification example, one embodiment is preferable from the viewpoint of reducing the difference in the shielding effect described above.

3.4 The fourth variation example Although not shown in the figure, the electromagnetic wave reflection sheet 1 may not include the adhesive layer 4 but only the base material 2 and the electromagnetic wave reflection layer 3 . The thickness 5 of the electromagnetic wave reflecting sheet 1 in the fourth variation is the total thickness of the base material 2 and the electromagnetic wave reflecting layer 3 .

When one embodiment is compared with the 4th modification, one embodiment is preferable. Since the electromagnetic wave reflecting sheet 1 of one embodiment includes the adhesive layer 4 , the electromagnetic wave reflecting sheet 1 can be reliably bonded to the object 9 .

3.5 The fifth variation example In the fifth modification, the roll body 7 has a winding core in the center. When one embodiment is compared with the 4th modification, one embodiment is preferable. In one embodiment, even if the roll body 7 has no winding core in the center, it can be manually formed into a small-diameter roll body 7 by the construction worker without causing damage, so it is easier to roll out the electromagnetic wave reflection sheet. After the step of material 1, when the small-diameter roller body 7 is rewound again for construction work, the winding core will not remain. As a result, environmental load can be reduced.

3.6 The sixth variation The electromagnetic wave reflection layer 3 is a laminate of the first inorganic oxide layer, the metal layer, and the second inorganic oxide layer. The first inorganic oxide layer and the second inorganic oxide layer each have the same configuration as the above-mentioned inorganic oxide layer. As the material of the metal layer, for example, it may include materials selected from Ti, Si, Nb, In, Zn, Sn, Au, Ag, Cu, Al, Co, Cr, Ni, Pb, Pd, Pt, Cu, Ge, Ru , one metal from the group consisting of Nd, Mg, Ca, Na, W, Zr, Ta, and Hf, or an alloy containing two or more of these metals. As a material of a metal layer, silver and a silver alloy are mentioned preferably. The thickness of the metal layer is, for example, not less than 5 nm and not more than 100 nm.

When one embodiment is compared with the 6th modification, one embodiment is preferable. According to one embodiment, discoloration caused by corrosion of the metal layer during long-term use can be suppressed.

3.7 The seventh variation The electromagnetic wave reflection layer 3 includes a plurality of metal layers. For example, the plurality of metal layers include a first metal layer and a second metal layer. Specifically, the electromagnetic wave reflection layer 3 is a laminate of the first inorganic oxide layer, the first metal layer, the second inorganic oxide layer, the second metal layer, and the third inorganic oxide layer.

3.8 Another Variation The order in the thickness direction when laminating the base material 2 , the electromagnetic wave reflecting layer 3 , and the adhesive layer 4 constituting the electromagnetic wave reflecting sheet 1 of the modified example is not limited.

The electromagnetic wave reflective sheet 1 of the modified example has a functional layer arranged between the electromagnetic wave reflective layer 3 and the base material 2 . As a functional layer, a hard coat layer, an antiblocking layer, and an optical adjustment layer are mentioned, for example. The functional layer is single layer or multilayer.

4.1 One implementation of the communication system One embodiment of a communication system including an electromagnetic wave reflecting sheet will be described with reference to FIG. 6 . The communication system 100 includes a transmitter 111 , a receiver 112 , and the above-mentioned electromagnetic wave reflecting sheet 1 .

The electromagnetic wave reflection sheet 1 is bonded to the first wall surface 121 of the wall 120 as an example of the object.

The transmitter 111 and the receiver 112 are arranged separately from each other. The transmitter 111 and the receiver 112 face the first wall surface 121 respectively.

Furthermore, an obstacle 130 is arranged in the communication system 100 . The obstacle 130 is disposed between the transmitter 111 and the receiver 112 .

4.2 The effect of an implementation mode In the communication system 100 , even if there is an obstacle 130 between the transmitter 111 and the receiver 112 , the electromagnetic wave emitted from the transmitter 111 is reflected by the electromagnetic wave reflection sheet 1 and reaches the receiver 112 . That is, the communication system 100 has a communication path for the electromagnetic wave emitted from the transmitter 111 to reach the receiver 112 after being reflected by the obstacle 130 and the electromagnetic wave reflecting sheet 1 .

5.1 Another implementation of the communication system In another embodiment, the same components and steps as in the first embodiment are assigned the same reference symbols, and their detailed descriptions are omitted. Moreover, another embodiment can exhibit the same operation and effect as one embodiment unless otherwise stated. Furthermore, one embodiment and another embodiment can be combined suitably.

Another embodiment of a communication system including two electromagnetic wave reflecting sheets will be described with reference to FIG. 7 . The communication system 100 includes a transmitter 111 , a receiver 112 , a first electromagnetic wave reflecting sheet 101 , and a second electromagnetic wave reflecting sheet 102 .

The first electromagnetic wave reflecting sheet 101 is attached to the first wall surface 121 of the wall 120 . The wall 120 further has a second wall surface 122 . The first wall surface 121 and the second wall surface 122 form an interior angle α of less than 180 degrees.

The second electromagnetic wave reflecting sheet 102 is bonded to the second wall surface 122 .

The transmission port of the transmitter 111 faces the first electromagnetic wave reflection sheet 101 . The first electromagnetic wave reflecting sheet 101 faces the second electromagnetic wave reflecting sheet 102 . The receiving port of the receiver 112 faces the second electromagnetic wave reflecting sheet 102 .

Furthermore, an obstacle 130 is arranged in the communication system 100 . The obstacle 130 is disposed between the transmitter 111 and the receiver 112 . The obstacle 130 faces each of the first wall surface 121 and the second wall surface 122 .

5.2 The effect of another embodiment In the communication system 100, even if an obstacle 130 is placed between the transmitter 111 and the receiver 112, the electromagnetic waves emitted from the transmitter 111 are reflected by the first electromagnetic wave reflection sheet 101 and the second electromagnetic wave reflection sheet 102 in sequence to the receiver 112 . That is, the communication system 100 has a communication path through which the electromagnetic waves emitted from the transmitter 111 are reflected by the first electromagnetic wave reflecting sheet 101 and the second electromagnetic wave reflecting sheet 102 in order and reach the receiver 112 . [Example]

Hereinafter, an Example and a comparative example are shown, and this invention is demonstrated more concretely. In addition, this invention is not limited at all by an Example and a comparative example. In addition, the specific values of the blending ratio (content ratio), physical property value, parameter, etc. used in the following description can be replaced by the blending ratio (content ratio), physical property value, parameter, etc. corresponding to the above-mentioned "embodiment" The upper limit (the value defined by "below" and "less than") or the lower limit (the value defined by "above" and "exceed") of the corresponding record.

<Example 1> A long polyethylene terephthalate (PET) film (a product called "DIAFOIL" manufactured by Mitsubishi Plastics, with a thickness of 125 μm) was prepared as a substrate 2 (implementation of the first step).

An ITO film is formed on one side of the substrate 2 as the electromagnetic wave reflection layer 3 (implementation of the second step). Specifically, the substrate 2 is attached to the vacuum sputtering apparatus, and is wound up while moving in close contact with the heated film-forming roll. While moving the substrate 2, the vacuum degree of the environment was set to 1×10 ^-4 Pa by an exhaust system equipped with a cryocoil and a turbomolecular pump. While maintaining the vacuum, an indium tin composite oxide (ITO) layer is formed on one side of the substrate 2 by sputtering (DC (Direct Current) magnetron sputtering). In the sputtering method, the indium tin composite oxide (ITO) layer was used as an ITO target material with a tin oxide concentration of 10% by mass, and it was set to introduce Ar and O ₂ (O ₂ flow ratio in the sputtering gas 0.5%) in a reduced pressure environment (0.4 Pa), adjust the horizontal magnetic field to 100 mT.

The adhesive layer 4 containing the acrylic adhesive composition is arranged on one surface of the electromagnetic wave reflection layer 3 by transfer printing (implementation of the third step). Thereby, the electromagnetic wave reflection sheet 1 provided with the base material 2, the electromagnetic wave reflection layer 3, and the adhesive agent layer 4 was manufactured. The thickness T of the electromagnetic wave reflecting sheet 1 is 150 μm. The thickness of each layer is shown in Table 1.

The electromagnetic wave reflecting sheet 1 is wound up to obtain the roll body 7 .

<Example 2 to Example 8 and Comparative Example 1 to Comparative Example 4> The electromagnetic wave reflecting sheet 1 was produced in the same manner as in Example 1, and then the roll body 7 was obtained. However, as described in Table 1, the thickness and physical properties of each layer were changed.

In Example 6, the protective layer 5 including UV curable resin is disposed between the electromagnetic wave reflection layer 3 and the adhesive layer 4 . The refractive index of the protective layer 5 is 1.52.

As shown in FIG. 3 , in Example 7, the adhesive layer 4 is arranged on the base material 2 on the side opposite to the electromagnetic wave reflection layer 3 relative to the base material 2 . That is, the adhesive layer 4 is arranged on the other surface in the thickness direction of the base material 2 . Thereby, the electromagnetic wave reflection sheet 1 provided with the adhesive layer 4, the base material 2, and the electromagnetic wave reflection layer 3 sequentially toward one side in the thickness direction is manufactured.

In Example 8, the electromagnetic wave reflection layer 3 having a first inorganic oxide layer with a thickness of 40 nm including ITO, a metal layer with a thickness of 10 nm including silver, and a second inorganic oxide layer with a thickness of 40 nm including ITO was formed. .

In Comparative Example 3, a first inorganic oxide layer containing ITO with a thickness of 40 nm, a first metal layer containing silver with a thickness of 10 nm, a second inorganic oxide layer containing ITO with a thickness of 80 nm, and a second inorganic oxide layer containing silver were formed. The second metal layer with a thickness of 10 nm and the electromagnetic wave reflection layer 3 including a third inorganic oxide layer with a thickness of 40 nm of ITO.

<Evaluation of Physical Properties of Electromagnetic Wave Reflecting Sheet 1 and Roll 7> The physical properties of the electromagnetic wave reflecting sheet 1 and the roll body 7 of each of Examples 1 to 8 and Comparative Examples 1 to 4 were evaluated. The results thereof are described in Table 1.

<Transmittance of electromagnetic wave reflective sheet 1 to light with a wavelength of 550 nm> The transmittance of the electromagnetic wave reflective sheet 1 to light with a wavelength of 550 nm was measured using an integrating sphere spectroscopic transmittance tester (DOT-3, manufactured by Murakami Color Technology Research Institute Co., Ltd.).

<Electromagnetic Wave Reflecting Sheet 1’s Shielding Effect on Electromagnetic Waves with a Frequency of 28 GHz> The shielding effect of the electromagnetic wave reflective sheet 1 on the electromagnetic wave with a frequency of 28 GHz before being wound into the roll body 7 was measured according to the free space method. In the free space method, the measurement device 11 shown in FIG. 5 above is used.

<Difference in the shielding effect of the electromagnetic wave reflecting sheet 1 before being wound onto the roll 7 and after being unwound from the roll 7> The electromagnetic wave reflecting sheet 1 is unwound from the roll body 7 . With respect to this electromagnetic wave reflection sheet 1, the shielding effect with respect to the electromagnetic wave of frequency 28 GHz was calculated|required in the same manner as above.

Then, the difference between the shielding effect of the electromagnetic wave reflecting sheet 1 before being wound up on the roll 7 and the shielding effect of the electromagnetic wave reflecting sheet 1 after being unwound from the roll 7 was obtained.

<Cracks in the electromagnetic wave reflection layer 3> The presence or absence of cracks in the electromagnetic wave reflection layer 3 was observed visually and with an optical microscope.

<Winding property of the electromagnetic wave reflecting sheet 1 to the roll body 7> The winding property of the electromagnetic wave reflecting sheet 1 to the roll body 7 was evaluated by the following criteria. Excellent: The electromagnetic wave reflecting sheet 1 was smoothly wound into the roll body 7 . Defect: The electromagnetic wave reflecting sheet 1 was not smoothly wound up into the roll body 7 .

<Appearance (Design) of Electromagnetic Wave Reflecting Sheet 1> Attach the electromagnetic wave reflection sheet 1 to the object 9 with the design. Appearance (design property) was evaluated by the following criteria. Excellent: Design that can clearly identify object 9. Bad: The design of Object 9 cannot be clearly identified.

＜Reflectivity to electromagnetic waves with a frequency of 28 GHz＞ The reflectivity of the electromagnetic wave reflective sheet 1 with respect to electromagnetic waves with a frequency of 28 GHz was evaluated by the following criteria. Excellent: The shielding effect on electromagnetic waves with a frequency of 28 GHz is above 9 dB Bad: The shielding effect on electromagnetic waves with a frequency of 28 GHz does not reach 9 dB

<Discoloration of electromagnetic wave reflection layer 3 after long-term use> The discoloration of the electromagnetic wave reflective layer 3 in the electromagnetic wave reflective sheet 1 after 120 days from being attached to the object 9 was evaluated by the following criteria.

Excellent: Discoloration was not observed. Good: Discoloration was slightly observed. Bad: Remarkable discoloration was observed.

<Visibility of the pattern formed by the electromagnetic wave reflection layer 3> The electromagnetic wave reflection layer 3 is etched and patterned. The visibility was evaluated by the following criteria. Excellent: No pattern was recognized. Good: A little pattern was visually recognized.

＜Manufacture, 1st test and 2nd test of communication system＞ Example 9 As shown in FIG. 6 , a communication system 100 including a transmitter 111 , a receiver 112 and the electromagnetic wave reflection sheet 1 of Example 1 was manufactured.

The electromagnetic wave reflecting sheet 1 is attached to the first wall surface 121 of the wall 120 . The wall 120 contains an electromagnetic wave absorber.

The transmitter 111 and the receiver 112 are arranged at a distance of 3 m. The electromagnetic wave reflecting sheet 1 is arranged on the middle line CL passing through the middle point CP of the transmitter 111 and the receiver 112 in an orthogonal shape.

The transmitter 111 and the receiver 112 each use a horn antenna. The horn antenna is connected to the network analyzer. The opening surface (sending port/receiving port) of the horn antenna faces the electromagnetic wave reflecting sheet 1 .

Furthermore, an obstacle 130 is arranged in the communication system 100 . The obstacle 130 is disposed on the middle point CP between the transmitter 111 and the receiver 112 .

Obstacle 130 is a plate. The material of the plate is aluminum. As shown by the solid line in FIG. 6 , the obstacle 130 has a width of 0.5 m, a height of 0.5 m, and a thickness of 0.003 m.

In this communication system 100 , electromagnetic waves are transmitted from the transmitter 111 toward the electromagnetic wave reflection sheet 1 . The first test is carried out. The electromagnetic wave reaches the receiver 112 after being reflected by the electromagnetic wave reflecting sheet 1 . The center frequency of the electromagnetic wave emitted from the transmitter 111 is 28 GHz. The output of the electromagnetic wave (transmission signal) of the transmitter 111 is 10 dBm. The angle θ1 is the same as the angle θ2.

Based on the signal strength detected after reaching the receiver 112, the first test (first test) was evaluated using the following criteria.

Good: The signal strength detected by the receiver 112 exceeds -20 dB. Good: The signal strength detected by the receiver 112 is below -20 dB and exceeds -40 dB. Bad: The signal strength detected by the receiver 112 is -40 dB or less.

In addition, as shown by the imaginary line in FIG. 6, the above test was evaluated by changing the size of the obstacle 130 to a width of 5 m, a height of 5 m, and a thickness of 2.5 m. The second test is carried out. The obstacle 130 in the second test (imaginary line) is larger than the obstacle 130 in the first test (solid line).

Embodiment 10, embodiment 11, comparative example 6 and comparative example 7 The communication system 100 was manufactured in the same manner as in Example 9, and then the first test and the second test were respectively implemented. In addition, as shown in Table 2, the kind of the electromagnetic wave reflection sheet 1 was changed.

Example 12 As shown in FIG. 7, the communication system 100 provided with the transmitter 111, the receiver 112, the 1st electromagnetic wave reflection sheet 101, and the 2nd electromagnetic wave reflection sheet 102 was manufactured. The first electromagnetic wave reflection sheet 101 and the second electromagnetic wave reflection sheet 102 are the electromagnetic wave reflection sheet 1 of Example 6, respectively.

The first electromagnetic wave reflecting sheet 101 is attached to the first wall surface 121 of the wall 120 . The wall 120 contains an electromagnetic wave absorber. The wall 120 further has a second wall surface 122 . The interior angle α formed by the first wall surface 121 and the second wall surface 122 is a right angle.

The second electromagnetic wave reflecting sheet 102 is bonded to the second wall surface 122 .

The transmitter 111 and the receiver 112 are arranged at a distance of 5 m.

The transmitter 111 and the receiver 112 each use a horn antenna. The horn antenna is connected to the network analyzer. The opening surface (transmitting port) of the horn antenna of the transmitter 111 faces the first electromagnetic wave reflecting sheet 101 . The first electromagnetic wave reflecting sheet 101 faces the second electromagnetic wave reflecting sheet 102 . The opening surface (receiving port) of the horn antenna of the receiver 112 faces the second electromagnetic wave reflecting sheet 102 .

Furthermore, an obstacle 130 is arranged in the communication system 100 . The obstacle 130 is disposed between the transmitter 111 and the receiver 112 . The obstacle 130 faces each of the first wall surface 121 and the second wall surface 122 .

Obstacle 130 is a plate. The material of the plate is aluminum. As shown by the solid line in FIG. 7 , the obstacle 130 has a width of 0.5 m, a height of 0.5 m, and a thickness of 0.003 m.

In this communication system 100 , electromagnetic waves are transmitted from the transmitter 111 to the first electromagnetic wave reflecting sheet 101 . The first test is carried out. The electromagnetic wave is firstly reflected by the first electromagnetic wave reflecting sheet 101 , then reflected by the second electromagnetic wave reflecting sheet 102 , and then reaches the receiver 112 . That is, the number of reflections of electromagnetic waves in Example 12 was set to two. The center frequency of the electromagnetic wave generated from the transmitter 111 is 28 GHz. The output of the electromagnetic wave (transmission signal) of the transmitter 111 is 10 dBm. The angle θ1 is the same as the angle θ2. The angle θ3 is the same as the angle θ4.

Based on the strength of the signal detected after reaching the receiver 112, the test was evaluated using the following criteria. Good: The signal strength detected by the receiver 112 exceeds -20 dB. Good: The signal strength detected by the receiver 112 is below -20 dB and exceeds -40 dB. Bad: The signal strength detected by the receiver 112 is -40 dB or less.

In addition, as shown by phantom lines in FIG. 7 , the above test was evaluated after changing the size of the obstacle 130 to a width of 5 m, a height of 5 m, and a thickness of 2.5 m (second test). The obstacle 130 in the second test (imaginary line) is larger than the obstacle 130 in the first test (solid line).

Comparative Example 5 Without disposing the wall 120 and the obstacle 130, according to the method (free space method) described in FIG. The first test and the second test were respectively implemented and evaluated in the same manner as above. That is, the number of reflections of electromagnetic waves in Comparative Example 5 was set to zero.

Comparative Example 8 The communication system 100 was evaluated in the same manner as Comparative Example 5. In Comparative Example 8, the number of reflections of electromagnetic waves was set to zero. However, regarding Comparative Example 8, the center frequency of electromagnetic waves was changed from 28 GHz to 3.6 GHz.

＜Evaluation of suitability for high-speed communication＞ The evaluations of the first test and the second test of Comparative Example 8 were both "good". However, Comparative Example 8 is not suitable for the fifth-generation standard (5G) because the center frequency of the transmission signal is as low as 3.6 GHz and the evaluation is performed without assuming obstacles. Therefore, it is considered that Comparative Example 8 lacks adaptability to high-speed communication. Furthermore, in Comparative Example 8, since the center frequency of the transmission signal is as low as 3.6 GHz, the obstacle 130 in the first test can be bypassed (diffraction), so it is presumed that the communication evaluation is "good".

On the other hand, the evaluation of the first test of Example 9 was "excellent". On the other hand, the evaluation of the second test of Example 9 was "defective". However, in Embodiment 9, the center frequency of the transmission signal is as high as 28 GHz, and a frequency band with less noise can be used, so the adaptability to high-speed communication of Embodiment 9 is evaluated as "excellent".

Regarding this content, also in Examples 10 and 11, and Comparative Example 5 to Comparative Example 7, there was the same tendency as above.

On the other hand, the evaluations of the first test and the second test of Example 12 were all "good". That is, regardless of the size of the obstacle 130, the communication performance is good. Furthermore, in the twelfth embodiment, the center frequency of the transmission signal is as high as 28 GHz. Therefore, a frequency band with less noise can be used, which can fully adapt to high-speed communication. Therefore, the adaptability to high-speed communication of the twelfth embodiment is "excellent".

[Table 1] Table 1 Examples, comparative examples Thickness of electromagnetic wave reflective layer [nm] Thickness of substrate [μm] Adhesive layer thickness [μm] Thickness of protective layer [nm] Thickness of electromagnetic wave reflective sheet [μm] Shielding effect on electromagnetic waves with a frequency of 28 GHz [dB] Transmittance to light with a wavelength of 550 nm[%] Difference in shielding effect ^*4 presence or absence of cracks Coilability Appearance (design) Reflectivity of Electromagnetic Waves Discoloration after long-term use Visibility of pattern after etching Example 1 130 125 25 - 150 15 85 Below 1.5 none excellent excellent excellent excellent good Example 2 130 350 50 - 400 15 85 Below 2.0 none excellent excellent excellent excellent good Example 3 130 25 25 - 50 15 85 Below 3.0 none excellent excellent excellent excellent good Example 4 25 125 25 - 150 9 86 Below 1.5 none excellent excellent excellent excellent good Example 5 160 125 25 - 150 twenty three 83 Below 3.5 none excellent excellent excellent excellent good Example 6 130 125 75 100 200 15 89 Below 1.5 none excellent excellent excellent excellent excellent Example 7 130 125 25 ^*3 - 150 15 85 more than 4 none excellent excellent excellent excellent good Example 8 90 ^*1 125 25 - 150 28 83 Below 2.5 none excellent excellent excellent good good Comparative example 1 130 25 15 - 40 15 85 4 or more have excellent excellent excellent excellent good Comparative example 2 130 400 100 - 500 15 85 4 or more none bad excellent excellent excellent good Comparative example 3 180 ^*2 125 25 - 150 30 78 4 or more none excellent bad excellent bad good Comparative example 4 20 125 25 - 150 7 90 Below 0.5 none excellent excellent bad excellent good *1: 40 nm thick ITO layer/10 nm thick Ag layer/40 nm thick ITO layer *2: 40 nm thick ITO layer/10 nm thick Ag layer/80 nm thick ITO layer/10 nm thick Ag layer/ITO layer with a thickness of 40 nm*3: The adhesive layer is located on the other side of the substrate in the thickness direction. *4: The difference between the shielding effect of the electromagnetic wave reflective sheet before it is wound onto the roll body and after it is unwound from the roll body

[Table 2] Types of electromagnetic wave reflective sheet Communication Frequency(GHz) number of reflections reference image 1st test (obstacle: small size) 2nd test (obstacle: large size) Adaptability to high-speed communication Example 9 Example 1 28 1 Figure 6 excellent bad excellent Example 10 Example 6 28 1 Figure 6 excellent bad excellent Example 11 Example 8 28 1 Figure 6 good bad good Example 12 Example 6 ^*1 28 2 Figure 7 good good excellent Comparative Example 5 none 28 0 (Figure 5) bad bad bad Comparative Example 6 Comparative example 4 28 1 Figure 6 bad bad bad Comparative Example 7 Comparative example 3 28 1 Figure 6 excellent bad excellent Comparative Example 8 none 3.6 0 (Figure 5) good good bad *1: Both the first electromagnetic wave reflecting sheet and the second electromagnetic wave reflecting sheet

In addition, although the said invention is provided as embodiment of the illustration of this invention, it is only an illustration and should not be interpreted limitedly. Variations of the present invention known to those in this technical field are included in the scope of the patent application described later. [Industrial availability]

Electromagnetic wave reflecting sheets are used in communication systems.

1: Electromagnetic wave reflective sheet 2: Substrate 3: Electromagnetic wave reflection layer 4: Adhesive layer 5: Protective layer 7: Roller body 9: object 10: face 11: Measuring device 12: Transmitting antenna 13: Receiving antenna 14: Network Analyzer 100: Communication system 101: The first electromagnetic wave reflective sheet 102: The second electromagnetic wave reflecting sheet 111: Transmitter 112: Receiver 120: wall 121: 1st wall 122: Second wall 130: Obstacles CL: middle line CP: middle point R: The diameter of the inner dimension of the roller body T: Thickness of electromagnetic wave reflective sheet α: inner angle θ1: angle θ2: angle θ3: angle θ4: angle

Fig. 1 is a schematic sectional view of an embodiment of the electromagnetic wave reflecting sheet of the present invention. Fig. 2 is a cross-sectional view of an object in which the electromagnetic wave reflecting sheet shown in Fig. 1 is arranged. Fig. 3 is a cross-sectional view of an electromagnetic wave reflecting sheet according to a third modification and its arrangement on an object. Fig. 4 is a schematic cross-sectional view of an electromagnetic wave reflecting sheet according to a first modification example and a second modification example. Fig. 5 is a schematic diagram of a measuring device for shielding effect. Fig. 6 is a schematic diagram of an embodiment of the communication system of the present invention. Fig. 7 is a schematic diagram of another embodiment of the communication system of the present invention.

1: Electromagnetic wave reflective sheet

2: Substrate

3: Electromagnetic wave reflection layer

4: Adhesive layer

7: Roller body

T: Thickness of electromagnetic wave reflective sheet

Claims (12)

An electromagnetic wave reflective sheet, which is sequentially provided with a base material and an electromagnetic wave reflective layer facing one side in the thickness direction, and The transmittance of light with a wavelength of 550 nm is above 83%, The shielding effect on electromagnetic waves with a frequency of 28 GHz is above 9 dB, The thickness is not less than 50 μm and not more than 400 μm. Such as the electromagnetic wave reflecting sheet of claim 1, which further has an adhesive layer, The adhesive layer forms one or the other surface of the electromagnetic wave reflecting sheet in the thickness direction. The electromagnetic wave reflecting sheet according to claim 1, wherein the adhesive layer forms one surface in the thickness direction of the electromagnetic wave reflecting sheet, and The electromagnetic wave reflective sheet has the base material, the electromagnetic wave reflective layer, and the adhesive layer arranged sequentially toward one side in the thickness direction. The electromagnetic wave reflective sheet according to claim 1, further comprising a protective layer in contact with one surface of the electromagnetic wave reflective layer in the thickness direction. The electromagnetic wave reflective sheet according to claim 4, wherein the refractive index of the above-mentioned protective layer is not less than 1.4 and not more than 1.6, and the thickness of the above-mentioned protective layer is not less than 40 nm and not more than 250 nm. The electromagnetic wave reflective sheet according to claim 1, wherein the electromagnetic wave reflective layer includes an inorganic oxide layer. A roll body, which is formed by winding the electromagnetic wave reflection sheet according to any one of Claims 1 to 6. For the roller body as claimed in claim 7, the diameter of its internal dimension is more than 40 mm. As the roll body of claim 7, there is no winding core in the center. A method of manufacturing an electromagnetic wave reflective sheet, comprising the following steps: Rolling the electromagnetic wave reflecting sheet according to any one of claims 1 to 6 to make a roll body; and rolling out the above-mentioned electromagnetic wave reflective sheet from the above-mentioned roller body; and The difference between the shielding effect of the electromagnetic wave reflective sheet before winding and the shielding effect of the electromagnetic wave reflective sheet unwound from the roll is 4.0 dB or less. A communication system comprising a transmitter, a receiver, and the electromagnetic wave reflecting sheet according to any one of claims 1 to 6, and It is provided with a communication path for the electromagnetic wave emitted from the above-mentioned transmitter to reach the above-mentioned receiver after being reflected by the above-mentioned electromagnetic wave reflective sheet. A communication system comprising a transmitter, a receiver, a first electromagnetic wave reflecting sheet, and a second electromagnetic wave reflecting sheet; and Each of the above-mentioned first electromagnetic wave reflecting sheet and the above-mentioned second electromagnetic wave reflecting sheet is the electromagnetic wave reflecting sheet according to any one of claims 1 to 6, The above-mentioned communication system has a communication path for the electromagnetic waves emitted from the above-mentioned transmitter to reach the above-mentioned receiver after being reflected by the above-mentioned first electromagnetic wave reflecting sheet and the above-mentioned second electromagnetic wave reflecting sheet in sequence.

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