JP2006140220A - Low-reflectivity conductive film, electromagnetic wave shielding film, and electromagnetic wave shielding translucent window material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic wave shielding translucent window material having a mesh-like conductive pattern of narrow line width and high numerical aperture. <P>SOLUTION: Dots 7 are printed on a transparent film 1 using a material soluble to solvent, such as water. An anti-glare layer 2, a metal layer 3 and an anti-glare layer 4 are then formed sequentially so as to cover the dots 7 on the film 1 and the exposed surface of all the films between the dots 7. Subsequently, the film 1 is cleaned with a solvent, such as water. A metal layer 3, having conductive pattern anti-glare layers 2 and 4 consisting of layers 2, 3 and 4 formed in the region between dots, is thereby left on the film 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a low-reflective conductive film useful as a front filter of a PDP (plasma display panel), a window material (for example, a sticking film) of a building such as a hospital that requires an electromagnetic wave shield, and the like. The present invention relates to an electromagnetic wave shielding film made of a film and an electromagnetic wave shielding light transmitting window material provided with the electromagnetic wave shielding film.

  In recent years, with the spread of OA equipment, communication equipment, etc., electromagnetic waves generated from these equipment have been regarded as a problem. That is, there are concerns about the influence of electromagnetic waves on the human body, and malfunctions of precision equipment due to electromagnetic waves are problematic.

  Thus, conventionally, a window material having an electromagnetic shielding property and a light transmission property has been developed and put into practical use as a front filter of a PDP of an OA device. Such a window material is also used as a window material for a precision device installation place such as a hospital or a laboratory in order to protect the precision device from electromagnetic waves such as a mobile phone.

  Conventional electromagnetic shielding light-transmitting window materials are mainly configured by integrating a conductive mesh material such as a wire mesh or a transparent conductive film between transparent substrates such as acrylic plates.

  The conductive mesh used for the conventional electromagnetic shielding light transmitting window material is generally about 5 to 500 mesh with a wire diameter of 10 to 500 μm, and the aperture ratio is less than 75%.

  As for the conductive mesh used conventionally, generally the thing of the wire diameter of the conductive fiber which comprises a mesh is coarse, and when a wire diameter becomes thin, it will become fine. This is because if the fiber has a large wire diameter, it is possible to form a coarse mesh, but it is very difficult to form a coarse mesh with a thin wire diameter.

  For this reason, in the conventional electromagnetic wave shielding light transmission window material using such a conductive mesh, even if the light transmittance is good, it is at most about 70%, and it is not possible to obtain good light transmittance. was there.

  In addition, the conventional conductive mesh has a problem that moire (interference fringes) is likely to occur due to the pixel pitch of the light emitting panel to which the electromagnetic wave shielding light transmitting window material is attached.

  Although it is conceivable to achieve both light transmittance and electromagnetic wave shielding properties by using a transparent conductive film in combination, the transparent conductive film has a problem that it is not easy to establish conduction with the housing.

  That is, in the case of a conductive mesh, as described above, the peripheral portion of the conductive mesh can be protruded from the peripheral portion of the transparent substrate, the protruding portion can be bent, and conduction from the bent portion can be achieved. In the transparent conductive film, when the peripheral edge of the transparent conductive film protrudes from the peripheral edge of the transparent substrate and is bent, the film is torn at the crease and cannot be electrically connected to the casing.

  In addition, instead of the transparent conductive film, it may be possible to form a transparent conductive film directly on the adhesive surface of one transparent substrate. In this case, the transparent conductive film is covered with the other transparent substrate. As a result, conduction from the transparent conductive film to the housing cannot be achieved.

  Therefore, when using a transparent conductive film, for example, a design change such as forming a through hole in a transparent substrate and providing a conductive path with the transparent conductive film is required. Assembly and assembly into the housing become complicated.

  In particular, when used for a PDP or the like, since the display surface is flat, light reflected in a wide range when external light is inserted enters the eyes of an observer at the same time, and the screen is difficult to see due to glare. Therefore, there was a problem that visibility was inferior.

Solving these problems, preventing the moire phenomenon, and providing an electromagnetic wave shielding light-transmitting window material that has extremely good light transmittance, electromagnetic wave shielding properties, heat ray (near infrared) cutting properties, and antiglare properties. Therefore, an electromagnetic wave shielding light transmitting window material in which a metal layer and an antiglare layer are laminated is described in JP-A-2002-374094. In the same reference, the antiglare layer is formed of black or dark ink.
JP 2002-374094 A

  As the above ink, a binder (ink medium) in which pigment fine particles are dispersed is used. In order to keep the fine particles dispersed in the ink, the viscosity of the ink needs to be sufficiently high. There is. For this reason, the ink line width cannot be remarkably reduced, and the aperture ratio cannot be remarkably increased.

  In addition, although it is also considered that the antiglare layer is formed by a blackening treatment of the metal layer, the treatment is troublesome and expensive, and only one surface of the metal layer can be blackened.

  The present invention provides a low-reflective conductive film that is excellent in anti-glare properties, has a sufficiently small line width, and can have a significantly high aperture ratio, and an electromagnetic shielding film and an electromagnetic shielding property having the low-reflective conductive film. An object is to provide a light transmission window material.

  The low reflective conductive film of the present invention (Invention 1) is a low reflective conductive film comprising an antiglare layer and a metal layer formed in a predetermined pattern on a transparent substrate, and the antiglare layer. Is made of a visible light absorbing metal oxide.

  The low reflective conductive film according to claim 2 is characterized in that, in claim 1, the conductive layer is made of at least one metal or alloy of Au, Ag, Cu and Al.

  The low reflective conductive film according to claim 3 is characterized in that, in claim 1 or 2, at least a part of the metal of the metal oxide is at least one of Ag, Cu and Cr.

  A low-reflective conductive film according to a fourth aspect is characterized in that, in any one of the first to third aspects, the antiglare layer is composed of an oxide of a metal constituting the metal piece. is there.

  According to a fifth aspect of the present invention, there is provided the low reflective conductive film according to any one of the first to fourth aspects, wherein the antiglare layer is formed of a sputtered thin film.

  The low reflective conductive film according to claim 6 is characterized in that, in any one of claims 1 to 5, the antiglare layer is formed on one side or both sides of a metal layer.

  According to a seventh aspect of the present invention, there is provided the low reflective conductive film according to any one of the first to sixth aspects, wherein the pattern is a stripe pattern or a mesh pattern.

  The electromagnetic wave shielding film of the present invention (invention 8) is an electromagnetic wave shielding film made of a low reflective conductive film, and the low reflective conductive film according to any one of claims 1 to 7. It is characterized by being.

  The electromagnetic wave shielding light transmitting window material of the present invention (invention 9) is an electromagnetic wave shielding light transmitting window material in which an electromagnetic wave shielding film is provided on a transparent substrate, and the electromagnetic wave shielding film is any one of claims 1 to 8. It is an electromagnetic wave shielding film described in item 1.

  In the present invention, since the antiglare layer to be laminated on the metal layer is formed of a visible light absorbing metal oxide, a fine pattern can be easily formed with high accuracy by a sputtering method or the like. By reducing this line width, the aperture ratio can be increased.

  According to the present invention, it is possible to provide an antiglare layer on both surfaces of the metal layer.

  Note that the antiglare layer can be formed very easily by using the same metal for the metal of the metal layer and the metal oxide of the antiglare layer.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is an enlarged cross-sectional view of an electromagnetic wave shielding light transmitting window material according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a manufacturing method thereof.

  The electromagnetic wave shield 10 includes a transparent film 1 and an antiglare layer 2, a metal layer 3, and an antiglare layer 4 formed on the transparent film 1 in a predetermined pattern.

  In order to manufacture this electromagnetic wave shield, dots 7 are printed on the transparent film 1 using a material soluble in a solvent such as water as shown in FIGS. 2 (a) and 2 (b). Next, as shown in FIG. 2C, the antiglare layer 2, the metal layer 3, and the antiglare layer 4 are sequentially formed so as to cover all the exposed surfaces of the film 1 on the dots 7 and between the dots 7. Next, the film 1 is washed with a solvent such as water. At this time, if necessary, dissolution accelerating means such as ultrasonic irradiation, rubbing with a brush, sponge or the like may be used in combination.

  Thereby, as shown in FIG. 2D, the soluble dots 7 are dissolved, and the layers 2, 3, and 4 on the dots 7 are also peeled off from the film 1 and removed. Then, the metal layer 3 with the conductive pattern antiglare layers 2 and 4 formed of the layers 2, 3 and 4 formed in the region between the dots remains on the film 1. Since this conductive pattern occupies the area between the dots 7, it has a mesh shape as a whole.

  Therefore, by reducing the gap between the dots 7, a mesh-like conductive pattern with a small line width is formed. Further, by increasing the area of each dot 7, a mesh-like conductive pattern having a large aperture ratio is formed. The printing material soluble in water or the like for forming the dots 7 does not need to disperse the fine particles, and a low viscosity material is sufficient. According to this low-viscosity printing material, dots can be printed so as to have a fine dot pattern.

  In addition, after the process of the said FIG.2 (d), an electromagnetic wave shielding light transmissive window material is obtained by carrying out finish washing | cleaning (rinsing) as needed and drying. In addition, by printing a stripe pattern instead of dots, a stripe-shaped conductive pattern can be formed with high accuracy.

  Next, suitable examples of each of the above materials will be described.

  As the transparent film 1, polyester, polyethylene terephthalate (PET), polybutylene terephthalate, polymethyl methacrylate (PMMA), acrylic plate, polycarbonate (PC), polystyrene, triacetate film, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene , Ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane, etc., preferably PET, PC, PMMA.

  The thickness of the transparent film varies depending on the use of the electromagnetic wave shielding light transmitting window material, but is usually about 1 μm to 5 mm.

  The dots formed on the film 1 are preferably formed by printing. As the printing material, a solution of a material that is soluble in a solvent for removing dots is used. The solvent for removing the dots may be an organic solvent, but water is preferable because it is inexpensive and has an impact on the environment. The water may be an aqueous solution containing an acid, an alkali or a surfactant in addition to normal water. This printing material may be mixed with a pigment or a dye to make it easy to check the print finish.

  In view of the relationship that the solvent is water, the dot-forming material is preferably a water-soluble polymer material, and specifically, polyvinyl alcohol or the like is preferred.

  The dots 7 are printed so that the film exposure area between them becomes a mesh shape or a stripe shape. Preferably, the film exposure region is printed so that the line width is 30 μm or less. As a printing method, gravure printing, screen printing, inkjet printing, and electrostatic printing are suitable, but gravure printing is suitable for thinning.

  In the case of dots, the shape is a tradition such as a circle, an ellipse, or a square, but is preferably a square, particularly a square.

  The printing thickness of the dots or stripes is not particularly limited, but is usually about 0.1 to 5 μm.

  After the printing of the dots or stripes, it is preferably dried, and then the antiglare layer 2, the metal layer 3, and the antiglare layer 4 are sequentially formed. The antiglare layers 2 and 4 are formed of a metal oxide having visible light absorption. As this metal oxide, at least one oxide of Ag, Cu, and Cr is suitable.

  The metal layer 3 is preferably made of at least one metal or alloy of low resistance Au, Ag, Cu, and Al.

  These layers 2, 3 and 4 are preferably formed by sputtering. As sputtering for forming the antiglare layers 2 and 4 made of a metal oxide, reactive sputtering and dual cathode sputtering are suitable. Such sputtering may be performed under the control of a plasma emission control method.

  In the present invention, the metal of the metal oxide constituting the antiglare layers 2 and 4 and the metal constituting the metal layer may be the same. In this way, in the sputtering process, the antiglare layer 2, the metal layer 3, and the antiglare layer 4 are continuously formed in this order by using the same target in the same apparatus only by controlling the supply of oxygen. Can be membrane. The layers 2, 3, and 4 constitute a low reflective conductive film.

  The thickness of the antiglare layers 2 and 4 is preferably 100 to 10000 mm, particularly preferably 100 to 1000 mm. If it is less than 100 mm, the light antireflection effect may not be sufficient. If it exceeds 10,000 mm, it is difficult to remove the pattern, and the apparent aperture ratio when viewed in perspective may be reduced.

  The thickness of the metal layer 3 is preferably about 0.5 to 100 μm. When this thickness is less than 0.5 μm, electromagnetic wave shielding performance may not be sufficient. On the other hand, when the thickness exceeds 100 μm, the thickness of the obtained electromagnetic shielding light-transmitting window material is affected and the viewing angle may be narrowed.

  After the formation of the layers 2, 3 and 4, as described above, the dots 7 are removed using a solvent, preferably water, and dried as necessary to obtain an electromagnetic wave shielding light transmitting window material.

  Although the antiglare layers 2 and 4 are provided in the above embodiment, only the antiglare layer 2 or only the antiglare layer 4 may be provided.

It is sectional drawing of the electromagnetic wave shielding light transmission window material which concerns on embodiment. It is typical sectional drawing which shows the manufacturing method of the electromagnetic wave shielding light transmission window material which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film 2, 4 Anti-glare layer 3 Metal layer 7 Dot 10 Electromagnetic shielding light transmission window material

Claims (9)

In a low reflective conductive film comprising an antiglare layer and a metal layer formed in a laminated pattern in a predetermined pattern on a transparent substrate,
A low reflective conductive film, wherein the antiglare layer is made of a visible light absorbing metal oxide.   2. The low reflective conductive film according to claim 1, wherein the metal layer is made of at least one metal or alloy of Au, Ag, Cu, and Al.   3. The low reflective conductive film according to claim 1, wherein at least a part of the metal of the metal oxide is at least one of Ag, Cu, and Cr.   4. The low-reflective conductive film according to claim 1, wherein the antiglare layer is composed of an oxide of a metal constituting the metal layer. 5.   5. The low-reflective conductive film according to claim 1, wherein the antiglare layer is formed of a sputtered thin film.   6. The low reflective conductive film according to claim 1, wherein the antiglare layer is formed on one side or both sides of a metal layer.   The low reflective conductive film according to claim 1, wherein the pattern is a stripe pattern or a mesh pattern.   An electromagnetic wave shielding film comprising a low reflective conductive film, wherein the low reflective conductive film is the low reflective conductive film according to any one of claims 1 to 7.   9. An electromagnetic wave shielding light transmitting window material in which an electromagnetic wave shielding film is provided on a transparent substrate, wherein the electromagnetic wave shielding film is the electromagnetic wave shielding film according to any one of claims 1 to 8. Light transmission window material.

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