JP2010135466A - Electromagnetic wave shielding material and plasma display panel equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic wave shielding material improved to cause no yellowish reflection light even when a conductive mesh formed of silver is used. <P>SOLUTION: The electromagnetic wave shielding material 10 includes a base material layer 11. On one surface of the base material layer 11, a hard coating layer 12 and an antireflective layer 13 are formed sequentially. On the other surface of the base material layer 11, an undercoat layer 14 is formed. On the undercoat layer 14, an ink receiving layer 15 to prevent bleeding (thickening of lines) of silver paste ink is arranged. On the ink receiving layer 15, an electromagnetic wave shielding mesh layer 16 formed by burning the silver paste ink is formed. The undercoat layer 14 is impregnated with a color correcting pigment to prevent the occurrence of yellowish reflection light from a silver mesh. A mold releasing film 18 is arranged on an adhesive layer 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention generally relates to an integrated electromagnetic shielding material having an electromagnetic shielding function, an antireflection function, a near-infrared absorbing function, and a color tone correction function, and more specifically, improved so as to improve image quality. The present invention relates to an electromagnetic shielding material. The present invention also relates to a plasma display panel provided with such an electromagnetic wave shielding material.

  FIG. 6 is a conceptual diagram of a conventional plasma display panel. 7 is a cross-sectional view taken along line VII-VII in FIG. With reference to these drawings, a filter 3 is disposed on the front side of the display unit 2 of the plasma display panel 1.

  The filter 3 includes a glass base layer 4, an antireflection film 5, a mesh film 6 and a protective film 7. The antireflection film 5 is formed by coating a PET film with an antireflection film 5a. The mesh film 6 is formed by forming a conductive mesh 6a on a PET film. The protective film 7 is formed of a PET film. The glass base material layer 4, the antireflection film 5, the mesh film 6, and the protective film 7 are bonded together with adhesive layers 8a, 8b, and 8c, respectively. As shown in FIG. 8, the conductive mesh 6a is formed in a lattice shape by screen printing using, for example, a silver paste. The connection pads 6b connected to the conductive gasket 9 so as to surround the lattice are also formed simultaneously with the conductive mesh 6a by screen printing.

  As shown in FIG. 7, the filter 3 is pressed and fixed to the front surface of the plasma display panel 1 so that the conductive gasket 9 and the connection pad 6b are in contact with each other.

  Near-infrared (NIR) cut dyes and color tone correction dyes are added to the adhesive layers 8a, 8b and 8c. By adding a near-infrared (NIR) cut pigment, the near-infrared rays radiated from the plasma display panel 1 are blocked, and a malfunction of a remote controller that works in the near-infrared rays is prevented. By adding the color tone correction dye, the balance between hue and brightness is adjusted.

  The harmful electromagnetic wave emitted from the plasma display panel 1 is captured by the conductive mesh 6a, passes through the connection pad 6b, the conductive gasket 9, and the casing, and is connected to the ground to escape.

  In the conventional method, as described above, since the number of adhesive / film layers is large, the number of parts is large, the work is complicated, and the cost is high. In addition, since the optical filter is formed of a glass substrate, it is easy to break, the roll-to-roll flow operation cannot be performed, and the work efficiency is lowered.

  Referring to FIG. 9, when light hits the back surface (surface near the viewer's eyes) of the conductive mesh 6a made of silver, yellowish reflected light is generated, which is reflected in the eyes, There was a problem of getting worse.

  The present invention has been made to solve the above-described problems, and provides an electromagnetic wave shielding material improved so as not to produce a yellowish reflected light even when a conductive mesh formed of silver is used. For the purpose.

  Another object of the present invention is to provide an electromagnetic wave shielding material which has an antireflection function, an electromagnetic wave shielding function, a near infrared ray absorbing function, and is integrated so as to reduce the number of parts.

  Another object of the present invention is to provide an integrated electromagnetic shielding material capable of realizing roll-to-roll and capable of being rolled up.

  Another object of the present invention is to provide a plasma display panel on which such an electromagnetic wave shielding material is mounted.

  The present invention relates to an electromagnetic wave shielding material that is disposed in front of a plasma display panel and shields an electromagnetic wave radiated from the plasma display panel, and includes a base material layer. A hard coat layer and an antireflection layer are sequentially provided on one surface of the base material layer. An ink receiving layer for preventing bleeding of the conductive paste ink is provided on the other surface of the base material layer. An electromagnetic wave shielding mesh layer formed by screen printing and baking of conductive paste ink is provided on the ink receiving layer. An undercoat layer is provided between the ink receiving layer and the other surface of the base material layer to block at least oligomer components and additives generated from the base material layer when the conductive paste ink is baked. . A dye for color tone correction is included in the undercoat layer.

  Since the undercoat layer is formed thick, it is possible to include a large amount of color correction pigment in the undercoat layer. Therefore, the color tone correction pigment can change the above-mentioned yellowish reflected light to a neutral gray (gray) that does not have a yellowishness, thereby improving the image quality.

  Moreover, by providing a pressure-sensitive adhesive layer containing a near-infrared (NIR) cut pigment on the ink receiving layer so as to cover the electromagnetic wave shielding mesh layer, and providing a release film on the pressure-sensitive adhesive layer, An electromagnetic wave shielding material having an antireflection function, an electromagnetic wave shielding function, and a near infrared absorption function can be obtained in the form of a single film.

  The base material layer is preferably formed of polyethylene terephthalate. This is because the film can be wound into a roll by adjusting the film thickness.

  The thickness of the undercoat layer is preferably 10 μm or more. By selecting the thickness in this way, not only a large amount of color correction pigment can be added, but also the generation of rainbow (rainbow spots) can be eliminated.

  By forming the undercoat layer with a UV curable acrylic urethane resin or epoxy acrylate, the process can be shortened and the productivity can be improved, but it may be formed with a thermosetting resin.

  The electromagnetic shielding mesh layer is formed by printing a conductive silver paste by a screen printing method.

  A plasma display panel according to another aspect of the present invention is provided with an electromagnetic shielding material having the above-described characteristics.

  When the present invention is used, functions such as antireflection, electromagnetic wave shielding, and color correction can be created on a single base film (for example, PET film) by coating or printing. A front filter can be constructed by pasting together. Further, since the undercoat layer contains a color correction pigment, yellowish reflected light from the conductive mesh formed of silver is eliminated, so that the image quality is improved.

  The purpose of obtaining an electromagnetic shielding material improved so as not to produce a yellowish reflected light even when using a conductive mesh formed of silver is to include a dye for color tone correction in the undercoat layer. Realized by. Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view of an electromagnetic wave shielding material 10 according to an embodiment of the present invention. The electromagnetic wave shielding material 10 includes a base material layer 11 formed of polyethylene phthalate (PET) having a thickness of 75 to 100 μm. On one surface of the base material layer 11, a hard coat layer 12 (1.5 μm thickness) and an antireflection layer 13 (0.1 μm thickness) are sequentially provided. An undercoat layer 14 (10 μm thick) is provided on the other surface of the base material layer 11. On the undercoat layer 14, an ink receiving layer 15 (1.0 μm thickness) for preventing bleeding (line thickening) of the silver paste ink is provided. The ink receiving layer 15 is a transparent porous layer and is formed of an aggregate of fine particles mainly composed of silica, titania, alumina or the like. An electromagnetic wave shielding mesh layer 16 formed by screen printing and baking of silver paste ink is provided on the ink receiving layer 15. Although not shown, the electromagnetic wave shielding mesh layer 16 is electrically connected to connection pads provided around it.

  According to the screen printing, the inclination angle θ of the mesh cross section of the electromagnetic wave shielding mesh layer 16 is in the range of 20 ° to 50 °. Screen printing of ink is preferable because the mesh cross-section becomes a saddle shape as shown in the figure, and air is hard to bite. Screen-printed ink exhibits conductivity by firing as described above. However, when baked, oligomers and additives are precipitated from the base material layer and become white. Therefore, the undercoat layer 14 that prevents precipitation of oligomers and additives is required. The undercoat layer 14 may be thin to prevent precipitation. However, a rainbow occurs at 8 μm or less. Therefore, an undercoat layer 14 having a thickness of 10 μm or more is provided.

  The reason why rainbows occur is that light originally has coherence, but light emitted from sunlight, fluorescent lamps, incandescent lamps, etc. strongly interferes with light of about 3 μm or less, and gradually interferes with light of 3 μm or more. Tend to weaken. When the thickness is 10 μm or more, the coherence is considerably weakened, so that the occurrence of substantial rainbow can be ignored.

  The undercoat layer 14 has a function of blocking diffusion of oligomer components and additives generated from the PET component of the base material layer 11 toward the electromagnetic wave shielding mesh layer 16 when the silver paste ink is baked. Although it is provided, the undercoat layer 14 contains a dye for color tone correction to prevent yellow reflected light from being generated from the silver mesh, which will be described later. An adhesive layer 17 containing a near-infrared (NIR) cut pigment is provided on the ink receiving layer 15 so as to cover the electromagnetic shielding mesh layer 16. A release film 18 is provided on the pressure-sensitive adhesive layer 17. The release film 18 is for preventing the films from adhering to each other when wound on a roll.

  According to this example, an electromagnetic wave shielding material having an antireflection function, an electromagnetic wave shielding function, and a near infrared ray absorbing function can be obtained in the form of a single film. Since the base material layer 11 is formed of polyethylene terephthalate, it can be wound into a roll by adjusting the film thickness, and a roll-to-roll operation can be realized.

  The film thickness of the undercoat layer 14 is 10 μm or more. By selecting the thickness in this way, it is possible not only to add a large amount of color correction pigment, but also to eliminate the occurrence of rainbow in this layer.

  The undercoat layer 14 can be formed of a UV curable acrylic urethane resin or epoxy acrylate to shorten the process and improve the productivity, but may be formed of a thermosetting resin.

  FIG. 2 is a conceptual diagram of a plasma display panel formed by mounting the electromagnetic shielding material 10 according to the embodiment. The release film 18 provided on the surface of the electromagnetic shielding material 10 is removed, the pressure-sensitive adhesive layer 17 is exposed, and this is bonded to a protective glass 19. Next, as shown in FIG. 3, the conductive gasket 9 and the connection pad 16b are pressed and fixed to the front surface of the plasma display panel 1 so as to be in contact with each other.

  According to the present embodiment, the electromagnetic shielding material 10 is composed of an integrated film having an antireflection function, an electromagnetic wave shielding function, and a near infrared ray absorbing function, so that the number of parts is small and the work is performed. It becomes easy. In addition, although the case where the glass 19 was used was illustrated, you may fix the electromagnetic wave shielding material 10 to the front surface of the plasma display panel 1 directly.

  According to this embodiment, referring to FIG. 4, since the coloring agent for color tone correction is included in the undercoat layer 14, the conductive mesh 16 formed of silver by the coloring agent for color tone correction. The reflected light from the surface closer to the viewer's eyes changes to neutral gray (gray) which does not have a yellowish tint, and the image quality is improved.

  FIG. 5 is a cross-sectional view illustrating the steps of the method for manufacturing the electromagnetic wave shielding material according to the second embodiment.

  Referring to FIG. 5 (A), a 75 μm thick PET base material layer 11 is prepared. On one surface of the PET base material layer 11, a 1.5 μm thick hard coat layer 12 having a refractive index of 1.60 to 1.75 and a 0.1 μm antireflection layer 13 having a low refractive index are easily formed. Sequentially formed without an adhesive layer. These are formed by coating.

  With reference to FIG. 5 (B), an underside of 10 μm thickness is provided on the other surface of the PET substrate layer 11 to block off oligomer components and additives generated from the PET substrate layer 11 when the conductive paste ink is baked. The coat layer 14 is formed. A dye for color tone correction is included in the undercoat layer 14.

  Here, how to make the undercoat layer 14 containing the color correction pigment will be described.

  A commercially available UV curable acrylic resin (JSR Co., Ltd. Z7524) was diluted with methyl ethyl ketone (MEK) to a solid content of 50%. The color correction pigment was added to the paint by dissolving it in MEK in advance.

  The dyes were added in three levels A, B, and C.

  (Level A) 0.0265% by weight of Arimoto Chemical Industry Co., Ltd. Violet 1803 and Green 1602, respectively, which are pigments for color tone correction, was added to the solid content of the paint.

  (Level B) 0.053% by weight of Violet 1803 and Green 1602 were added to the solid content of the paint.

  (Level C) Violet 1803 and Green 1602 were added in an amount of 0.0795% by weight based on the solid content of the paint.

  With reference to FIG. 5C, an ink receiving layer 15 having a thickness of 1.0 μm is formed on the undercoat layer 14 in order to prevent bleeding (line thickening) of the silver paste ink.

  Referring to FIG. 5D, conductive paste ink is screen-printed on ink receiving layer 15. The conductive paste ink is composed of conductive powder and a binder. For example, it is formed in a lattice shape by screen printing using a silver paste. The conductive paste ink is baked at 150 ° C. or higher to form the electromagnetic shielding mesh layer 16. At this time, oligomer components and additives generated from the PET component of the PET base material layer 11 are blocked by the undercoat layer 14, and are prevented from moving toward the electromagnetic wave shielding mesh layer 16.

  Referring to FIG. 5D, an adhesive layer 17 containing a near-infrared (NIR) cut pigment is formed on the ink receiving layer 15 so as to cover the electromagnetic shielding mesh layer 16.

  Referring to FIG. 5E, a release film 18 is formed on the pressure-sensitive adhesive layer 17 so that the films do not adhere to each other when wound on a roll. Next, the obtained electromagnetic wave shielding material is wound up in a roll shape.

In any of the above levels (A), (B), and (C), the reflected light from the conductive mesh was neutral gray (gray), and the image quality was not deteriorated.
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The electromagnetic wave shielding material according to the present invention has an antireflection function, an electromagnetic wave shielding function, and a near-infrared absorption function. Further, the number of parts is reduced, and yellowish reflected light is not generated.

It is sectional drawing of the electromagnetic wave shielding material which concerns on this invention. It is a conceptual diagram of the plasma display panel which affixed the electromagnetic wave shielding material which concerns on this invention. It is sectional drawing which follows the III-III line in FIG. It is a figure for demonstrating the effect of the plasma display panel which affixed the electromagnetic wave shielding material which concerns on this invention. The process of the manufacturing method of the electromagnetic wave shielding material which concerns on this invention is shown with sectional drawing. It is a disassembled perspective view of the functional film with which the conventional plasma display panel is mounted. It is sectional drawing which follows the VII-VII line in FIG. It is a top view of a conductive mesh. It is a figure which shows the problem of the functional film with which the conventional plasma display panel is mounted | worn.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma display panel 2 Display part 3 Filter 4 Glass base material layer 5 Antireflection film 5a Antireflection film 6 Mesh film 6a Conductive mesh 6b, 16b Connection pad 7 Protective film 8a, 8b, 8c Adhesive layer 9 Conductive gasket 10 Electromagnetic shielding material 11 PET base layer 12 Hard coat layer 13 Antireflection layer 14 Undercoat layer 15 Ink receiving layer 16 Electromagnetic wave shielding mesh layer 16b Connection pad 17 Adhesive layer 18 Release film 19 Glass

Claims (7)

An electromagnetic shielding material that is disposed on the front surface of the plasma display panel and shields electromagnetic waves emitted from the plasma display panel,
A base material layer;
A hard coat layer and an antireflection layer sequentially provided on one surface of the base material layer;
An ink receiving layer provided on the other surface of the base material layer for preventing bleeding of the conductive paste ink;
An electromagnetic wave shielding mesh layer formed by screen printing and baking of conductive paste ink provided on the ink receiving layer,
An undercoat layer is provided between the ink receiving layer and the other surface of the base material layer to block at least oligomer components and additives generated from the base material layer when firing the conductive paste ink,
An electromagnetic wave shielding material comprising a dye for color tone correction in the undercoat layer. A pressure-sensitive adhesive layer containing a near-infrared (NIR) cut pigment provided on the ink receiving layer so as to cover the electromagnetic wave shielding mesh layer;
The electromagnetic wave shielding material according to claim 1, further comprising a release film provided on the pressure-sensitive adhesive layer.   The electromagnetic wave shielding material according to claim 1, wherein the base material layer is formed of polyethylene terephthalate.   The electromagnetic shielding material according to claim 1, wherein the undercoat layer has a thickness of 10 μm or more.   The electromagnetic wave shielding material according to claim 1, wherein the undercoat layer is formed of a UV curable acrylic urethane resin, epoxy acrylate, or thermosetting resin.   The film thickness of the said base material layer is an electromagnetic wave shielding material of any one of Claims 1-5 made into the thickness in which the said electromagnetic wave shielding material can be wound up in roll shape.   A plasma display panel comprising the electromagnetic shielding material according to claim 1.