JP2003249791A - Light-transmissive electromagnetic wave shielding filter for display, base material thereof and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chemical resistant and reliable light-transmissive electromagnetic wave shielding filter for a display, a base material thereof and a manufacturing method thereof by improving adhesives used for the base material and ensuring the smoothness of the base material. <P>SOLUTION: The base material of the light-transmissive electromagnetic wave shielding filter for a display comprises an electromagnetic shielding layer 11 of thin metal foil formed by the photoetching process, a transparent plastic film 14, and adhesive layers 12, 13 provided between the electromagnetic shielding layer 11 and the transparent plastic film 14. The adhesive layers 12, 13 comprise a plurality of adhesive layers. The adhesive forming the layer 12 in contact with the thin metal foil 11 exhibits heat resistance and chemical resistance in the photoetching process. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-transmitting electromagnetic wave shielding film for a display, a substrate therefor, and a method for manufacturing the same, which is a light-transmitting electromagnetic wave shielding film substrate capable of shielding electromagnetic waves generated from the front surface of a display. Regarding materials

[0002]

2. Description of the Related Art In recent years, there has been a remarkable amount of advanced information technology in society. One of the essential things to achieve these is a display. It is widely used not only in TVs, but also in word processors, personal computers, analytical equipment, game consoles, in-vehicle monitors of automobiles, mobile phones, and the like. Also, the size of each
There is a remarkable reduction in weight.

On the other hand, electromagnetic waves emitted from electric and electronic devices are becoming a big social problem. Electromagnetic waves may cause noise in surrounding equipment and cause it to malfunction. Due to the increase in the number of electric and electronic devices themselves and the use of computers for controlling each device, it is easy for problems to occur.
It can lead to serious accidents. It has also been pointed out that there is a risk of health problems to the human body. Laws and regulations have already been established in Europe and the United States, and manufacturers in Japan have voluntary regulations. As a method for shielding this electromagnetic wave,
There are methods such as making the device housing itself a metal body or a highly conductive body, inserting a metal plate between circuit boards, and winding a thin metal foil around a cable.

However, CRT, PDP (plasma), E
Regarding the electromagnetic waves radiated from the display surface such as L, if the above-mentioned method is adopted, the most important function of "seeing" inherent in the display will not be satisfied. Therefore, the electromagnetic wave shield for the display surface is required to have both electromagnetic wave shielding property and transparency for obtaining visibility. The electromagnetic wave shield filter attached to the display surface will be described with reference to FIG. Since the electromagnetic wave shield filter 6 is installed on the surface of the display, it is required to have both high transparency and electromagnetic shieldability. The antireflection layer 61 is provided on the surface, and a hard transparent substrate (glass, 62, and an electromagnetic wave shield layer 63. Each member is bonded to the hard transparent substrate 62 using an adhesive.

Various methods have been proposed as methods for achieving both electromagnetic wave shielding properties and transparency. Among them, as disclosed in Japanese Patent Laid-Open No. 10-41682, a transparent plastic film and a conductive material are bonded with an adhesive, and a geometrical figure (simply a mesh shape) is formed on the conductive material by a chemical etching process. It has been found that placing the shield film on the front of the display gives the best characteristics. This manufacturing method and materials are based on the manufacturing method of a flexible printed wiring board, and the equipment and method are almost established methods.

[0006]

[Problems to be Solved by the Invention] However, CR
The electromagnetic wave shield filter used for T and PDP is not only very large in size as compared with a wiring board including a general-purpose flexible printed circuit board, but is also made of a highly transparent material in order to ensure light transmission and display quality. In addition to using, it is necessary to form very fine fine lines on the entire surface for pattern processing of the electromagnetic wave shield layer, which is an obstacle to yield improvement in this manufacturing process and is a bottleneck for price reduction. Has become. Of course, no screen distortion should occur, and for this purpose, the electromagnetic wave shield layer is also required to have high flatness.

A factor affecting both the improvement in yield and the securing of flatness is the quality of the substrate to be processed.
It is optimal in terms of efficiency and cost that this base material is manufactured by continuously laminating a thin metal foil such as copper foil and a transparent plastic film such as PET using an adhesive and by a hot roll laminating method. Is. The adhesive used here has high transparency, and generally, an acrylic type, an epoxy type, a polyester type, or a combination thereof is used. Transparency is a characteristic inherent to adhesives, and there is no problem if selected, but it is necessary to meet the following requirements. The transparent plastic film used as the substrate generally has low heat resistance, and it is preferable that the temperature at the time of attachment to the copper foil is as low as possible. PET film is the most influential material in view of price, transparency and surface smoothness, but in order to use this film, it is necessary to bond them at a temperature of 120 ° C. or lower. If the temperature is higher than this, the film itself is deformed by the influence of heat and pressure, and the smoothness of the substrate cannot be ensured. In the etching process of thin metal foil, there is a high-temperature acid / alkali treatment process that can withstand it. More specifically, the liquid used for etching the thin metal foil is a strong acid at 40 ° C.
It is about the liquid temperature. Further, in removing the used etching resist, the solution temperature is about 40 ° C. with a strong alkaline solution. If the chemical resistance of the adhesive is low, discoloration or floating occurs during the treatment of this etching step, surface deterioration occurs, and transparency is lost. Need long term reliability. This depends on the final product composition, but is generally 80 ° C x 1000 hours. 6
It is evaluated by a treatment such as 0 ° C. × 95% × 1000 hours. There should be no visible alteration such as discoloration or blistering when treated under these conditions.

In the conventional method for producing a substrate, an adhesive is continuously applied on a transparent plastic film and heat laminated with a thin metal foil such as a copper foil. During this thermal lamination, only the adhesive softens due to heat. As a result, the adhesive must be sufficiently softened in order to secure the adhesion between the metal thin film and the adhesive. It is considered that this adhesion is required to be at least about 100 gf / cm in consideration of circuit peeling of the thin metal foil during processing and product reliability.

In thermal lamination, the heating time at the time of bonding is instantaneous. In order to satisfy both the sufficient softening of the adhesive and the short heating time, it is necessary to set the temperature of the heat roll at the time of production to be much higher than the Tg of the adhesive and to set the pressure to be large.

Further, in order to use the light-transmitting electromagnetic wave shielding film, the heat resistance and
Since importance is attached to chemical resistance and reliability, it is preferable that the adhesive used mainly contains a high molecular weight material having a relatively high Tg. With such a formulation, the softening temperature of the adhesive increases and the degree of softening also decreases.

As a result of the above, the temperature and pressure at the time of sticking the copper foil / transparent plastic film become high, the plastic film having poor heat resistance among the materials is deformed, and the smoothness of the substrate described above is ensured. Will be difficult.

The present invention has been made in view of the above problems. In the electromagnetic shield filter substrate, the adhesive used is improved, the smoothness of the substrate is ensured, and the chemical resistance,
An object of the present invention is to provide a highly reliable light-transmitting electromagnetic wave shield filter for a display, a base material thereof and a manufacturing method thereof.

[0013]

That is, the present invention is
Conventionally, it was difficult to satisfy all the requirements at the same time because the base material was formed with one adhesive layer.By configuring the adhesive layer with multiple layers, each requirement is shared by each layer. The aim is to satisfy and.
In terms of production, the manufacturing cost increases as the number of layers increases,
It is preferable that the number of layers is small. As a result of diligent studies, it was found that the required characteristics can be satisfied by using two adhesive layers. More specifically, first, an adhesive is applied to the metal thin film. Next, the adhesive is continuously applied on the transparent plastic film. Then, the applied adhesives are thermally laminated to each other.

The present invention is a display light comprising an electromagnetic wave shielding layer formed by photoetching a thin metal foil, a transparent plastic film, and an adhesive layer provided between the electromagnetic wave shielding layer and the transparent plastic film. A transparent electromagnetic wave shield filter substrate, wherein the adhesive layer is a light transparent electromagnetic wave shield filter substrate for a display, which is composed of a plurality of layers of adhesive.

Further, in the present invention, the adhesive of the layer of the adhesive layer which is in contact with the thin metal foil is a light-transmitting electromagnetic wave shield filter substrate for a display which has heat resistance and chemical resistance in the photoetching step. .

The present invention is a display comprising an electromagnetic wave shield layer formed by photoetching a thin metal foil, a transparent plastic film, and an adhesive layer provided between the electromagnetic wave shield layer and the transparent plastic film. A method for producing a light-transmitting electromagnetic wave shield filter substrate for use, comprising a step of forming a layer made of an adhesive having heat resistance and chemical resistance in a photoetching step on a thin metal foil, and a transparent plastic film on the transparent plastic film. The step of forming an adhesive layer, a thin metal foil having a layer made of an adhesive having heat resistance and chemical resistance in the photoetching step, and a transparent plastic film having an adhesive layer Of a light-transmitting electromagnetic wave shield filter substrate for a display having a step of facing each other and laminating It is a method.

Further, the present invention is a light-transmitting electromagnetic wave shield filter for a display, comprising an antireflection layer, a hard transparent plate and a base material, wherein the base material is the above-mentioned base material for display light. It is a transparent electromagnetic wave shield filter.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described.
Hereinafter, the light-transmitting electromagnetic wave shield filter for display of the present invention, the base material thereof, and the manufacturing method thereof will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a configuration explanatory view of a light-transmitting electromagnetic wave shield filter substrate of an example.
FIG. 2 is a schematic explanatory diagram of a laminating machine of the manufacturing apparatus of the light transmitting electromagnetic wave shield filter base material of the embodiment.

The structure of the substrate 1 obtained by the present invention is as follows.
As shown in FIG. 1, it comprises a copper foil 11, a first adhesive layer 12, a second adhesive layer 13, and a transparent substrate 14. The following description will be given in the order of steps for producing the base material 1. This base material 1
The thin metal foil 11 used for is not limited in type as long as it is a thin metal foil of copper, nickel, aluminum or the like, but the price,
Copper foil is considered to be the most suitable when considering fine wire workability and productivity. Further, as the type of copper foil 11, those commercially available for printed wiring boards are preferable. The copper foil 11 is chemically treated on the surface in contact with the first adhesive layer 12 to improve the adhesion with the adhesive layer 12 and to obtain good results in terms of reliability after commercialization. There is an advantage that it is easy to be taken Copper foil 11
As a general-purpose product, a thin foil having a thickness of 18 or 12 μm or less can be used.

A first adhesive layer 12 is formed on the copper foil 11. The adhesive used is required to be transparent, have chemical resistance in the etching process of the thin metal foil, and endure the reliability test after commercialization. As a material, an acrylic type, an epoxy type, a polyester type, or a mixture thereof is used as a main material. The glass transition temperature of this adhesive is preferably 40 ° C. or higher. The reason is to prevent coloration in the etching process. This is because if the Tg of this layer is low, it is softened by the high-temperature treatment liquid exposed in the etching process and the color of the liquid adheres. It has been confirmed that the treatment liquid temperature in the general etching step is about 40 ° C., and that the Tg of the adhesive layer is about 40 ° C., there is no coloring. Further, by lowering the liquid temperature in the process, the softening of the adhesive layer 12 is suppressed, and the color is less likely to adhere, but it is necessary to lower the speed with the process.
Productivity is poor.

As a method of forming the first adhesive layer 12,
A continuous coating method was used. This method is a method in which a solution of an adhesive in a solvent is applied on the copper foil 11 in a predetermined thickness and dried to remove the solvent. The thickness of the adhesive layer 12 after removing the solvent is preferably thin so that the speed in the coating step can be improved, but if it is too thin, defects in the coating film increase. Generally, it is considered to be about 3 to 20 μm. The step of main coating is continuously performed, and is wound into a roll through the steps of coating and solvent removal.

Further, according to the present method, since the first adhesive layer 12 is formed on the thin metal foil 11 by coating, the thin metal foil 11 / adhesive is used as compared with the conventional method of bonding with heat and pressure. The adhesive force at the interface of the layer 12 has not only a large value but also the advantage that it is stable.

Next, the second adhesive layer 13 is formed on the transparent substrate 14.
To form. A transparent plastic film is used as the transparent substrate 14. Suitable plastic films for this purpose include acrylic, polycarbonate, polyethylene, polypropylene, polyester, etc., because of their transparency, film smoothness, ease of handling, price, and availability of various thickness products. Polyester film (hereinafter,
"PET film") is considered optimal.
The second adhesive 13 is formed on the PET film 14 by a coating method. The coating method is the same as the method for forming the first adhesive 12 on the copper foil 11 described above, and thus description thereof will be omitted.

The second adhesive layer 13 is intended to bond the above-mentioned thin metal foil 11 / first adhesive layer 12 and the transparent substrate 14 at a low temperature. The PET film 14 used this time is the most suitable base material for this application, but since it is formed while being stretched in four in-plane directions during film production,
When subjected to high temperature treatment, the stress existing inside is released, and there is a drawback that deformation such as shrinkage or distortion occurs.

In the conventional base material, an adhesive having a relatively high Tg (40 ° C. or higher) is used in order to ensure reliability in the final product, and this adhesive is used to continuously bond the copper foil. When I try to attach the PET film coated with the agent,
The roll surface temperature at the time of thermal lamination requires a temperature of 130 ° C. or higher, which causes deformation of the PET film, causes distortion and wrinkles, and significantly reduces the production yield.

The second adhesive 13 used in the present invention is the same as the first adhesive, or does not come into contact with the chemical liquid during the processing of the substrate, so an adhesive having a lower Tg than the first adhesive 12 is used. it can. Next, the copper foil 11 coated with the first adhesive and the second
The adhesives of the PET film 14 coated with the adhesive of are opposed to each other and thermally laminated. According to this method
Since it is possible to bond the both with a slight softening of the adhesive, not only the surface temperature of the heat roll at the time of lamination can be lowered to near the Tg of the adhesive, but also the pressure can be lowered. It is possible to obtain a high-quality and high-performance substrate in which the deformation of the substrate is suppressed.

The adhesive force at the interface between the first adhesive layer 12 and the second adhesive layer 13 is that the entire surface is adhered,
It was also confirmed that it is possible to obtain sufficient reliability at 100 gf / cm or more by not directly touching the outside air.

The Tg (glass transition temperature) of the adhesive
Is a DSC (differential scanning calorimeter) [manufactured by Shimadzu Corporation,
DSC-50], an aluminum cell containing the sample was attached, and the temperature was raised from -40 ° C to 150 ° C at a rate of 20 ° C / min.
After heating up to ℃ and holding at 150 ℃ for 3 minutes, the cooling rate is 2
The point of the calorific value (J / g) that appeared when cooled to around room temperature at 0 ° C./min was measured.

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Example 1 will be described. A copper foil 18 μm thick product (trade name; BHY-22B-T, manufactured by Japan Energy Co., hereinafter abbreviated as “copper foil”) for printed wiring boards is used as the thin metal foil 11.
As the transparent plastic film, a polyester film having a thickness of 125 μm (product: Emblet S, manufactured by Unitika Ltd., hereinafter abbreviated as “film”) was used.

First, the copper foil 11 was coated with a first adhesive.
As the first adhesive, a polyester adhesive (trade name: Byron UR-1400, manufactured by Toyobo Co., Ltd.) was used. This adhesive has a Tg of 83 ° C. This adhesive was continuously applied onto the copper foil 11 and dried. Drying condition is 120 ℃ × 1
The thickness of the adhesive layer 12 after drying was 10 μm.

Next, the same adhesive was applied on the film 14. The coating conditions are the same as the coating on the copper foil 11. The thickness is also 10 μm.

Both coated products were continuously roll-laminated. The outline of the laminating machine is shown in FIG. The structure of this equipment is general, and comprises an unwinding device 2 for the material to be laminated, a preheating device 3 before laminating, a laminating roll 4 capable of heating / pressurizing, and a winding device 5. The preheating device 3 heats the object to be laminated in advance so that the object to be laminated at a low temperature is deformed by a rapid temperature change when it comes into contact with the heating / pressurizing roll 4 and wrinkles are formed, so that the temperature change is moderated. It is installed for the purpose of processing and is an indispensable facility when processing a film or thin metal.

Next, the adhesive layers of both coated products were bonded together by continuous lamination. The laminating speed was fixed at 2 m / min in consideration of productivity (the same applies to the following examples). As a result of various studies on the laminating conditions, the temperature of the non-laminated product by the preheating is 70 to 80.
℃, laminating roll surface temperature 105 ℃, pressure 10 Kg
Good results were obtained at / cm.

A second embodiment will be described. Thin metal foil used 1
1 is the same as in Example 1. As the second adhesive, DIALAL BR-64 (acrylic resin manufactured by Mitsubishi Rayon Co., Ltd.) was used. The Tg of this adhesive is 55 ° C. Thin metal foil 1
1 and the conditions for coating the adhesive on the film 14 are the same as in Example 1. As a result of various studies on laminating conditions, good results were obtained when the temperature of the object to be laminated by preheating was 55 to 65 ° C., the surface temperature of the laminating roll was 95 ° C., and the pressure was 10 kgf / cm.

A third embodiment will be described. 12 μm thick copper foil for printed wiring board as thin metal foil 11 (trade name; SQ-VL
P, manufactured by Mitsui Mining & Smelting Co., Ltd. Japan Energy, hereinafter abbreviated as "copper foil") was used. First, a third adhesive was applied to the copper foil 11. The third adhesive is an epoxy resin (trade name; Araldite LSAC6006, manufactured by Asahi Chiba Co., Ltd.)
For 100 parts, methyl tetrahydrophthalic anhydride 6
A mixture of 0 parts and 0.5 parts of 2-methyl 4-ethylimidazole was used. The Tg of the adhesive after curing is 88 ° C. This adhesive was continuously applied onto the copper foil 11 and dried. The drying condition was 120 ° C. × 1 minute, and the thickness of the adhesive layer 12 after drying was 10 μm.

Next, as a film to be adhered, an adhesive film (trade name: Hitalex L-811) having a polyester film of 25 μm and an adhesive of 10 μm applied
0, manufactured by Hitachi Chemical Co., Ltd.) 14 was used. This adhesive has a Tg of -5 ° C. As a result of various examinations regarding the laminating conditions, the temperature of the object to be laminated by preheating is 25 ° C
Good results were obtained (room temperature), the surface temperature of the laminating roll was 25 ° C. (room temperature), and the pressure was 15 kgf / cm.

A comparative example 1 will be described. A substrate was manufactured by using only one layer of the adhesive used in Example 1. As a procedure, the film was coated with an adhesive and laminated with a copper foil. The thickness of the adhesive was 10 μm, and the coating conditions were the same as in Example 1.

As a result of various examinations on the laminating conditions, the temperature of the object to be laminated by preheating was 115 to 13
0 ℃, laminating roll surface temperature 150 ℃, pressure 20k
Good results were obtained at gf / cm.

A comparative example 2 will be described. As the adhesive, Dynal BR-64 (acrylic resin manufactured by Mitsubishi Rayon Co., Ltd.) was used. The Tg of this adhesive is 55 ° C. A substrate was manufactured with only one layer of this adhesive. As a procedure, the film was coated with an adhesive and laminated with a copper foil. The thickness of the adhesive was 10 μm, and the coating conditions were the same as in Example 1.

As a result of various studies on the laminating conditions, the temperature of the object to be laminated by preheating was 100 to 11
0 ℃, laminating roll surface temperature 120 ℃, pressure 20k
Good results were obtained at gf / cm.

The results of Examples 1-3 and Comparative Examples 1 and 2 are shown in FIG. As a result, in Examples 1-3, there were no distortions and wrinkles, which was good, but in Comparative Examples 1 and 2, slight distortions and wrinkles were generated, which were defective.

As described in the above examples, the light-transmitting electromagnetic shield filter base material obtained in the present invention can be manufactured in a low temperature process by forming the adhesive layer in two layers. As well as ensuring product reliability, it is possible to produce a high-quality electromagnetic shield film with excellent shape and high yield.

[0043]

According to the present invention, in the electromagnetic shield filter substrate, the light-transmitting electromagnetic wave for a display which improves the adhesive used, secures the smoothness of the substrate, and has chemical resistance and reliability. It is possible to obtain a shield filter, its base material, and its manufacturing method.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a light-transmitting electromagnetic wave shield filter base material of an example.

FIG. 2 is a schematic explanatory view of a laminating machine of a manufacturing apparatus of a light transmitting electromagnetic wave shield filter base material of the embodiment.

FIG. 3 is a chart for explaining measurement results of Examples and Comparative Examples.

FIG. 4 is an explanatory diagram of an outline of an electromagnetic shield filter.

[Explanation of symbols]

1 Light-transmitting electromagnetic wave shield filter substrate 11 Copper foil 12, 13 Adhesive layer 14 Transparent substrate 2 Unwinding device 3 Preheating device 4 Laminating roll 5 Winding device 6 Electromagnetic shield filter 61 Antireflection layer 62 Hard transparent plate 63 Electromagnetic wave shield layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09F 9/00 313 G09F 9/00 313 // B29L 7:00 B29L 7:00 9:00 9:00 (9 72) Inventor Masamitsu Fukuyama 1150 Gozamiya, Shimodate City, Ibaraki Prefecture Goseimiya Works, Hitachi Chemical Co., Ltd. (72) Hiroshi Nomura 1150 Gozamiya, Shimodate City, Ibaraki Prefecture Goshomiya Project, Hitachi Chemical Co., Ltd. In-house F-term (reference) 4F100 AB01A AB17 AB33A AK01B AK41G AK42 AR00D AR00E BA03 BA05 BA10A BA10B BA10D CB00C EJ15A GB41 JB01C JD08A JJ03C JK12E TA03TA03TA50A TA03TA03A03AD0301 TN03A02AD03AD03Q04A03A0317 BB21 CC16 GG05 GH01 5G435 AA14 BB02 BB05 BB06 GG33 KK07 LL07 LL08

Claims (4)

[Claims] 1. A light-transmitting display for a display comprising an electromagnetic wave shield layer formed by photoetching a thin metal foil, a transparent plastic film, and an adhesive layer provided between the electromagnetic wave shield layer and the transparent plastic film. An electromagnetic wave shield filter base material, wherein the adhesive layer is composed of a plurality of layers of adhesive agent. 2. The light transmissive electromagnetic wave shield filter substrate for a display according to claim 1, wherein the adhesive of the layer of the adhesive layer which is in contact with the thin metal foil has heat resistance and chemical resistance in the photoetching step. 3. A light-transmitting display for a display comprising an electromagnetic wave shield layer formed by photoetching a thin metal foil, a transparent plastic film, and an adhesive layer provided between the electromagnetic wave shield layer and the transparent plastic film. A method of manufacturing an electromagnetic wave shield filter substrate, comprising a step of forming a layer made of an adhesive having heat resistance and chemical resistance in a photo etching step on a thin metal foil, and an adhesive layer being formed on a transparent plastic film. The forming process, the thin metal foil on which a layer made of an adhesive having heat resistance and chemical resistance in the photoetching process is formed, and the transparent plastic film on which the adhesive layer is formed, the adhesives are opposed to each other. A process for producing a light-transmitting electromagnetic wave shield filter substrate for a display, which comprises a step of laminating by a laminating method. Method. 4. A light transmissive electromagnetic wave shield filter for a display, comprising an antireflection layer, a hard transparent plate, and a base material, wherein the base material is the base material according to claim 1. A light-transmitting electromagnetic wave shield filter for displays, characterized by.