JP2001237588A - Film of electromagnetic wave shielding characteristics and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost electromagnetic wave shielding film which is excellent in construction characteristics, visibility, weather resistance, and scratch resistance. SOLUTION: An electromagnetic wave shielding element comprising a conductor pattern is provided on one surface of a transparent plastic film, on which or on its rear surface, a black ink layer aligned with the electromagnetic wave shielding element comprising the conductor pattern is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film to be applied to windows of buildings and windows of vehicles such as automobiles and trains, and to a film having electromagnetic shielding performance.

[0002]

2. Description of the Related Art In recent years, as the use of PHS and wireless LAN in business establishments has been spreading, from the viewpoint of preventing information leakage and preventing malfunctions and noise due to external invading radio waves,
It is essential to prepare a radio wave environment in an office, and various types of members have been already proposed as members for maintaining such a radio wave environment.

An electromagnetic wave shielding material is one of members for maintaining a radio wave environment. As a commonly used electromagnetic wave shielding material, there is a metal foil, but this cannot be used for a portion such as a window that requires transparency of visible light. Although there is a method of forming a thin metal thin film in order to provide transparency of visible light, it is difficult to achieve both a sufficient electromagnetic wave shielding property and transparency of visible light. A material using a metal mesh to increase the transparency of visible light while maintaining sufficient electromagnetic wave shielding properties, or a metal layer (silver) as described in JP-A-63-38515 is formed by an oxide layer. There is an example in which the transparency of visible light is improved by pinching.

[0004] In addition, I
There is also an example in which a transparent conductive film such as TO or titanium oxide is deposited.
(JP-A-63-141399)

However, since these electromagnetic wave shielding materials cannot select the frequency of the electromagnetic wave to be shielded, it blocks even important public information such as radio waves of mobile phones and radios used inside and outside the building. Further, in the case of an electromagnetic wave shielding material using such a metal film or a transparent conductive film, it is necessary to keep contact with other conductive members such as a window frame and a pillar, so that the construction is very difficult and complicated in practice.

For this purpose, an example has been developed in which a metal pattern is periodically arranged on a film to block only electromagnetic waves at a specific frequency. (JP-A-10-12609
0) With this type of electromagnetic wave shielding material, there is no need to make contact with a metal sash or the like of the frame, so that the construction is very easy in practice.

[0007] However, since the metal pattern is used, when the interior is brighter than the exterior, the visibility from the interior to the exterior is reduced due to the reflected light from the metal pattern.

In order to improve the visibility, a black layer may be provided on the indoor side of the metal linear antenna. JP-A-9-29
3989 uses a black resist for forming a metal pattern layer, and a black layer is provided on the metal pattern by leaving the black resist on the metal pattern. In this configuration, an electromagnetic wave shielding film is attached to the indoor side. However, if the black layer is to be provided on the indoor side rather than the metal pattern, the black resist and the metal pattern are exposed on the surface. Therefore, the oxidation of the metal pattern and the rubbing of the surface during cleaning are taken into account. In this case, it is not preferable in terms of weather resistance and scratch resistance.

Further, as a method of preventing the metal pattern from being exposed on the surface, Japanese Patent Application Laid-Open No. 9-298384 discloses an example in which a metal pattern is provided on a dyed layer, and portions other than the metal pattern are decolorized in the etching step. In this case, the metal pattern is between the window glass and the base film and is not exposed on the surface, but there is a problem in cost due to the use of a special ink.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the conventional electromagnetic shielding material. In other words, it blocks only electromagnetic waves of a specific frequency and does not need to be in contact with the surrounding conductive material such as a metal sash, and is excellent in workability. Another object of the present invention is to provide an inexpensive electromagnetic wave shielding film which is favorable in terms of weather resistance and scratch resistance when oxidation of a metal pattern and rubbing of a surface during cleaning are taken into consideration.

[0011]

According to the present invention, there is provided an electromagnetic wave shielding element comprising a conductive pattern on one surface of a transparent plastic film, and a back surface thereof. In addition, the present invention provides a film having an electromagnetic wave shielding property, characterized in that the film has a black ink layer in register with the electromagnetic wave shielding element made of a conductor pattern.

According to a second aspect of the present invention, an electromagnetic wave shielding element made of a conductor pattern is provided on one surface of the transparent plastic film, and the register between the transparent plastic film and the conductor pattern coincides with the electromagnetic wave shielding element made of the conductor pattern. An object of the present invention is to provide a film having an electromagnetic wave shielding property, characterized by having a black ink layer formed thereon.

According to a third aspect of the present invention, there is provided a method for producing a film having an electromagnetic wave shielding property, wherein a black ink layer is formed by a printing method.

The film having an electromagnetic wave shielding property of the present invention is provided with a black printed layer, which is in register with the linear antenna, between the room and the metal pattern. Good visibility outside the room can be obtained, and visibility as a film is improved.

In the present invention, no special ink is required because a normal printing method is used, so that the manufacturing cost can be kept low.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a cross-sectional view of one embodiment of a film having electromagnetic wave shielding properties in which a black ink layer as a printing layer 1 is provided on a surface opposite to a metal pattern 3 of a transparent plastic film as a substrate 4 in order to increase visibility. FIG. 2 is a cross-sectional view of an embodiment of a film having an electromagnetic wave shielding property in which a black ink layer as a printing layer 1 is provided between a transparent plastic film as a substrate 4 and a linear antenna as a metal pattern 3.

In the configuration shown in FIG. 1, the antenna which is the metal pattern 3 is at the interface with the glass 1 and is not exposed to the surface, so that the weather resistance is high, and the glass / antenna pattern / film is viewed from the outdoor side. / Black ink layer, the reflected light from the metal pattern is suppressed by the black ink layer when the outside is viewed from the indoor side.

Further, in the case of the configuration shown in FIG. 2, the order of glass / antenna pattern / black ink layer / film is from the outdoor side, and when the outdoor is viewed from the indoor side, the reflected light from the metal pattern 3 is black ink. Layer, so that even the black ink layer is not exposed on the surface.

The printing method used for providing the black ink layer includes, but is not limited to, a gravure printing method and an ink jet printing method.

As a method of registering the linear antenna with the black ink layer, when a linear antenna is first formed, an alignment mark used for positioning when forming the linear antenna is simultaneously formed. And, after using the method of using the linear antenna pattern itself for alignment after creating a linear antenna, the method of providing an alignment mark used for alignment after forming the linear antenna with a laser marker, etc. And a printing method in which the black ink layer is registered with the metal pattern by using the alignment mark.

If a black ink layer is to be formed first, an alignment mark used for alignment is provided at the end of the film, and an aluminum foil is attached to the center so that the alignment mark is not hidden. Utilizing the method, a method in which a resist layer is registered on a metal foil in register with a black ink layer and printed is used.

By using these methods, it is possible to form a black ink layer having the same register as the linear antenna.

Here, the register coincidence means that the shapes of the upper and lower layers are visually coincident with each other. Misalignment of the alignment mark portion and the like does not hinder the present invention, and is included in those whose registrations match, including those that do not visually match.

Further, the black ink herein means a color that does not hinder visibility, and is not optical black.
The black of the present invention can be included even if it is dark gray as long as the black does not cause visual impairment. However, from the viewpoint of the function and effect, the higher the density, the higher the effect. Therefore, it is preferable to use a general black ink as it is. In consideration of weather resistance and the like, a special weather-resistant ink may be used instead of a general ink.

【Example】

FIGS. 3 to 7 show an example of a production process for a film having an electromagnetic wave shielding property in which the black ink layer of the present invention is provided on a surface of a transparent plastic film having no linear antenna.

First, a metal layer 6 is provided on the entire surface of a transparent base 4. Examples of the method of forming the metal layer 6 include lamination of metal foil, vacuum deposition, and sputtering.

Next, a resist layer 7 is patterned into a metal layer. At this time, an alignment mark (not shown) used to match the register when printing the black ink layer as the printing layer 5 is also formed on the resist layer 7 at the same time.

Subsequently, portions of the metal layer 6 not covered by the resist layer 7 are removed by etching. At this time, the resist remaining on the pattern 3 may be removed after the completion of the etching.

Finally, on the surface of the base 4 on which the metal layer 6 is not formed, the register is made coincident with the metal pattern 3 by using the alignment mark provided by leaving the metal layer 6, and the black ink layer as the printing layer 5 is formed. Print.

FIGS. 8 to 11 show one example of a manufacturing process for a film having an electromagnetic wave shielding property in which the black ink layer of the present invention is provided between metal patterns of a transparent plastic film. However, the base itself is the same as in FIG.

First, an alignment mark (not shown) for registering the shape of the metal pattern 3 and the end with the transparent base 4 is printed with a black ink as the printing layer 5.

A metal foil is stuck on the surface of the transparent substrate on which the black ink is printed so that the alignment marks printed on the edges are not hidden, thereby forming a metal layer 6.

Using the alignment mark, a resist layer 7 is provided on the metal layer 6 so as to match the pattern of the black ink pattern. At this time, as a method of providing the resist layer 7 in register with the black ink layer, there is a method of printing a resist using an alignment mark, a method of aligning a mask using an alignment mark, and exposing the resist.

Finally, a portion of the metal layer 6 that is not covered with the resist layer 7 is removed by etching, and the metal pattern 3 is removed.
And At this time, the resist remaining on the metal pattern 3 may be removed after the etching is completed.

Example 1 A photoresist was printed in a pattern on a film in which a 15-μm aluminum foil was laminated on a 50-μm-thick PET film, exposed to light, and after forming a pattern and an alignment mark with the photoresist, Then, etching was performed to form a metal pattern and an alignment mark on the PET film.

Using an alignment mark, a black ink pattern having the same register as the metal pattern is printed on the surface of the PET film on which the metal pattern is not formed, using a normal black ink, and a film having electromagnetic wave shielding properties is printed. Produced.

(Example 2) A photoresist was printed in a pattern on a film obtained by evaporating 3 μm of aluminum on a PET film having a thickness of 50 μm, exposed to light, and a pattern and an alignment mark were formed with the photoresist.
Etching was performed to form metal patterns and alignment marks on the PET film. Using a positioning alignment mark, a black ink pattern having the same register as that of the metal pattern was printed on the surface opposite to the metal pattern of the PET film using ordinary black ink to prepare a film having electromagnetic wave shielding properties.

Example 1 and Example 2 thus obtained
All of the films having the electromagnetic wave shielding property described above had an electromagnetic wave shielding performance of 30 dB or more at the target frequency, and did not show the luster of the metal pattern when looking from a bright room to a dark outdoor.

A change in scratch resistance was examined when the metal layer was on the inner surface of the film and when the metal layer was on the surface. The abrasion resistance test was conducted while applying a load of 50 g to steel wool.
It was measured by reciprocating.

Example 3 After printing a pattern similar to a metal pattern and a registration mark for registration on a 50-μm-thick PET film with black ink,
An aluminum foil having a thickness of 15 μm was stuck so as not to hide the alignment mark for registration. A resist layer printed using the alignment mark so as to match the pattern printed with the black ink and printed was provided, and a film having electromagnetic wave shielding properties was produced.

(Comparative Example 1) Using a film in which a 15-μm aluminum foil was laminated on a 50-μm-thick PET film, a black photoresist was exposed to light, a pattern and alignment marks were formed, and then etching was performed. In addition, a metal pattern was formed on a PET film to produce a film having electromagnetic wave shielding properties.

In Comparative Example 1, both the black resist layer and the metal layer were peeled off, but in Example 3, the black ink layer and the metal layer were not affected.

[0043]

As described in detail above, according to the present invention, since small linear antennas are regularly arranged, only electromagnetic waves of a specific frequency are shielded, and the workability is excellent.
By providing a black ink layer between the metal layer and the room, it is possible to obtain a film having excellent electromagnetic wave shielding properties with excellent visibility.

According to the first aspect of the present invention, an electromagnetic wave shielding property for shielding only an electromagnetic wave of a specific frequency, a simple workability requiring no installation, and a black ink layer are provided between the conductor pattern and the room. Excellent visibility can be obtained. In addition, since there is no conductor pattern on the surface, it has excellent scratch resistance and weather resistance.

By using the invention described in claim 2,
Electromagnetic wave shielding that only shields electromagnetic waves of a specific frequency,
Simple workability that does not require installation, and excellent visibility by providing a black ink layer between the conductor pattern and the room can be obtained. In addition, since there is no conductor pattern on the surface, it has excellent scratch resistance and weather resistance.

Further, since there is no black print layer on the surface,
The black printed layer also has excellent scratch resistance. By using the invention of claim 3, it is possible to produce an electromagnetic wave shielding film at lower cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a sectional view showing one step of a manufacturing method according to one embodiment of the present invention.

FIG. 4 is a sectional view showing one step of a manufacturing method according to one embodiment of the present invention.

FIG. 5 is a sectional view showing one step of a manufacturing method according to one embodiment of the present invention.

FIG. 6 is a sectional view showing one step of a manufacturing method according to one embodiment of the present invention.

FIG. 7 is a sectional view showing one step of a manufacturing method according to one embodiment of the present invention.

FIG. 8 is a sectional view showing one step of a manufacturing method according to another embodiment of the present invention.

FIG. 9 is a sectional view showing one step of a manufacturing method according to another embodiment of the present invention.

FIG. 10 is a sectional view showing one step of a manufacturing method according to another embodiment of the present invention.

FIG. 11 is a sectional view showing one step of a manufacturing method according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass 2 Adhesive layer 3 Metal pattern 4 Substrate 5 Printing layer 6 Metal layer 7 Resist layer

Claims (3)

[Claims] An electromagnetic wave shield comprising an electromagnetic wave shielding element made of a conductor pattern on one surface of a transparent plastic film, and a black ink layer on the back surface of which is in register with the electromagnetic wave shielding element made of a conductor pattern. Film with properties. 2. An electromagnetic wave shielding element comprising a conductor pattern is provided on one surface of a transparent plastic film, and a black ink layer having the same register as the electromagnetic wave shielding element comprising a conductor pattern is provided between the transparent plastic film and the conductor pattern. A film having an electromagnetic wave shielding property characterized by having. 3. A method for producing a film having electromagnetic wave shielding properties, wherein the black ink layer of the film having electromagnetic wave shielding properties according to claim 1 or 2 is formed by a printing method.