JP4047841B2 - Shielding material for electromagnetic wave shielding - Google Patents

Description

  The present invention relates to a shield material for shielding EMI (Electromagnetic Interference) of flat display products such as PDP, and more particularly, a matte black on the front and side surfaces of a copper foil mesh that is deposited on a substrate and patterned. The present invention relates to a shield material for EMI shielding in which a conductive coating layer is formed.

  In the present specification, patterning means etching a copper foil adhered on a film to form a predetermined pattern, and the patterned copper foil means that a predetermined pattern is formed through the patterning. It means the formed copper foil.

  In this specification, the mesh means a copper foil portion that has not been etched on the patterned copper foil.

  In the present specification, the front surface means the mesh surface on the opposite side of the film.

  In this specification, the back means the mesh surface on the film side.

  In the present specification, the side surface means the remaining surface of the mesh excluding the front surface and the back surface.

  Recently, plasma display panels (PDPs) characterized by being self-luminous, easy to see, wide viewing angles, large screens, and fast driving speeds have been widely used. The PDP generates a line spectrum with a wide wavelength from the ultraviolet region to the near infrared region. Therefore, this may cause a malfunction of a remote control device or an optical communication device that operates in the vicinity of the PDP. Moreover, since this is harmful to the human body, an electromagnetic shielding material is necessary to prevent this.

  However, the shielding material used for the display product such as PDP must have not only an electromagnetic wave shielding effect but also an appropriate translucency so that the image of the image reproduction portion can be seen through the electromagnetic wave shielding material. That is, the two purposes of electromagnetic shielding and translucency need to be achieved together.

  Therefore, a fine pattern having openings is formed on a glass or transparent resin plate using a conductive metal, for example, copper, thereby ensuring light transmission as well as an electromagnetic shielding effect.

  However, when the patterned conductive metal layer has a metallic luster, the incident light is emitted when the light emitted from the PDP display screen is reflected by the shield plate and returns to the display screen or when light enters the PDP display screen from the outside. Will be reflected.

  For this reason, the light transmittance of the shield plate is lowered, and the visibility of the display screen is deteriorated. To solve this problem, a method of blackening the surface of the copper foil has been used. It was. Using such a copper foil surface blackening method, only the back surface of the copper foil is blackened, and then an etching process is performed to remove unnecessary portions to form a necessary predetermined pattern on the film. In the figure, a patterned copper foil with only the back surface blackened was realized.

  FIG. 1 is a schematic view showing a copper foil having a mesh in which only the conventional back surface is blackened.

  As shown in FIG. 1, a copper foil having a mesh that is blackened only on the back surface is patterned on the film base 1 through the etching process on the copper foil 2 that has already been blackened on the back surface. As a result, only the back surface 3 of the mesh was blackened, and the blackening treatment was not performed on the remaining front surface 4 and side surface 5.

  However, in the patterned copper foil, blackening treatment is applied not only to the back surface but also to the front surface and all remaining side surfaces in order to prevent visibility reduction due to the light reflection that still exists despite the back surface blackening treatment. Need to be done.

  In the past, in order to satisfy such a requirement, the remaining surface except the back surface was blackened using an insulating or conductive oxide film or chemical conversion film. There was a problem like this.

  Table 1 below compares the main characteristics of each blackening method.

  As can be seen from Table 1, in the case of the insulating oxide film, it is non-conductive. However, in the blackening treatment of the front and side surfaces, it is particularly necessary to ensure the conductivity. Is difficult to apply to the blackening treatment of the front and side surfaces, and in the case of the conductive oxide film, it is difficult to completely blacken.

  Also, in the case of the chemical conversion film, since the resistance is high and the conductivity is non-uniform, it is difficult to apply to the blackening treatment of the front surface and the side surface where the conductivity must be ensured. The disadvantage is that processing is necessary.

  Therefore, in the blackening process after patterning, while improving the visibility by preventing light reflection from the front and side surfaces, it is easy to process while achieving complete blackening and at the same time ensuring proper conductivity. Therefore, it is necessary to apply a blackening technique different from the conventional technique.

  Accordingly, the present invention has been devised to solve the above-described demands and problems, and the object of the present invention is a base material suitable for use in a shielding material for electromagnetic wave shielding such as PDP. A matte black conductive coating layer is formed on the front and side surfaces of the copper foil mesh formed on the surface of the copper foil.

  That is, the present invention achieves complete blackening so that light is not reflected from the front and side surfaces of the copper foil mesh, ensures appropriate conductivity, is easy to process, and has a matte black conductivity that does not fall off black particles. A coating layer is provided on the front and side of the copper foil mesh.

  An object of the present invention as described above is to provide a shielding material for shielding electromagnetic waves including a transparent base material and a copper foil mesh adhered in a patterned state to the surface of the base material. In addition, it is achieved by forming a thin and uniform conductive coating layer.

The coating layer is a matte black electroplating layer containing iron (Fe) and at least one other metal component, and a large number of ultrafine nodules for realizing low roughness on the surface thereof. Is formed. In particular, the coating layer is preferably made of copper-cobalt-iron-nickel (Cu-Co-Fe-Ni).

  The front and side surfaces of the mesh are surface-treated by the patterned copper foil having the front and side surfaces treated with the conductive material of the present invention, thereby preventing light reflection by the front and side surfaces and ensuring favorable visibility. While achieving complete blackening, it has excellent workability and conductivity, is matte, has no black particles, has excellent oxidation resistance, heat resistance, and chemical resistance, and has good peel strength. Further, the effect of obtaining a uniform blackening layer with a thinner thickness can be achieved.

  Hereinafter, an electromagnetic wave shielding shield material in which a matte conductive coating layer is formed on the surface of a patterned copper foil mesh according to the present invention will be described in detail.

  According to the present invention, a patterned copper foil having a mesh whose front and side surfaces are treated with a conductive material is different from the conventional blackening technique used for the front and side surfaces. Are coated with a conductive material, and a coating layer of the conductive material is formed by electroplating to prevent light reflection from the front and side surfaces, while ensuring desirable visibility, while achieving complete blackening and appropriate While ensuring easy electrical conductivity while simultaneously facilitating processing, and furthermore, the electroplating layer comprises iron and at least one or more other metal components, in particular the components have a predetermined content. By forming with electroplating layer, it is excellent in oxidation resistance, heat resistance and chemical resistance as a matte black electroplating layer where black particles do not fall off, and peeling Time is good, and also based on the technical idea that the effect of preventing the decrease in transmittance at uniform thin thickness of the black electroplating layer is achieved.

  A patterned copper foil having a front and side treated mesh with a conductive material according to the present invention is obtained by treating the front and side of the mesh with a conductive material after patterning of the copper foil adhered on the film. It becomes like this.

  FIG. 2 shows an electromagnetic shielding shield material having a mesh 20 having a front surface 40 and side surfaces 50 treated with a conductive material according to an embodiment of the present invention.

  As shown in FIG. 2, the shielding material for electromagnetic wave shielding according to an embodiment of the present invention includes a base material 10 and a patterned copper foil attached on the base material. Here, the front surface 40 and the side surface 50 of the patterned copper foil mesh are coated with a conductive material 60. The substrate 10 is preferably a thin transparent plate for allowing light to pass through, for example, a transparent plastic.

  Note that the back surface 30 of the mesh 20 has already been surface-treated. As a surface treatment method, various conventional blackening treatment techniques are used, and the iron (Fe) component according to the present invention described below is included. Needless to say, a blackening treatment technique by electroplating using an electrolytic solution is also used.

  The coating layer made of the conductive material 60 is preferably formed by electroplating. Thus, when electroplating is performed, unlike the case of using an oxide film, a chemical conversion film, etc., complete blackening can be achieved, and good conductivity and workability can be ensured.

  Meanwhile, the electroplating layer is a matte black electroplating layer made of at least one metal excluding iron (Fe) and iron (Fe). The outer metal other than iron is one or more selected from the group including copper (Cu), cobalt (Co), nickel (Ni), zinc (Zn), arsenic (As), and tungsten (W). Any metal can be used.

The plating layer may be a copper-iron-cobalt or copper-iron-nickel metal combination, but is most preferably made of copper-cobalt-iron-nickel.
The plating layer preferably has a thickness limited to about 1 μm or less so as to be suitable for high-density wiring.

The plating layer 30 is copper, the cobalt, if made of nickel and iron, copper is 1 to 4 mg / ^{m 2,} wherein the cobalt is 1000~2000mg / ^{m 2,} wherein the iron be 300 to 600 mg / m @ 2 The content of nickel is preferably adjusted to 7 to 15 mg / m ² .

Incidentally, the content of the copper is less than 1 mg / m ^2, become metallic luster comes into its surface difficult formation of very fine nodules as satisfied is equal to or 4 mg / m ² or more, very fine nodules Phenomenon that falls due to excessive lamination.

Further, when the cobalt content is less than 1000 mg / m ² , brown ultrafine nodules are electrodeposited to reduce the blackness, and when it is 2000 mg / m ² or more, the cost is improved compared to the increased cost. Very few physical properties.

If the iron content is less than 300 mg / m ² , it will be difficult to form a satisfactory ultrafine nodule and the surface will have a metallic luster, and if it exceeds 600 mg / m ² , Excessive rise causes excessive heat generation, which increases current loss and sharply reduces power efficiency.

When the nickel content is less than 7 mg / m ² , the blackness of the ultra fine nodules decreases, and a peeling phenomenon occurs from the base material after the blackening treatment. When the nickel content is 15 mg / m ² or more, the etching property is poor. Become.

  That is, when the plating layer has the above-mentioned content range, it is possible to form a dark black plating layer in which black particles do not fall out, it is matte, and it has excellent etching properties, chemical resistance, heat resistance, and oxidation resistance. It has a high peel strength and has a desirable surface roughness.

Furthermore, the plating layer, if the content is, copper 2-3 mg / ^{m 2,} cobalt 1100~1500mg / ^{m 2,} so that the iron 400~550mg / ^{m 2} and nickel 10~13mg / ^{m 2,} black It becomes more excellent in terms of degree and matteness.

  Thus, when the electroplating layer according to the present invention is made of a metal component containing at least iron, an effect of treating ultra fine nodules is achieved on the plating layer. The ultra fine nodule treatment effect is due to the iron contained in the plating layer, whereby not only the particles to be plated are uniformly dispersed, but also low roughness is achieved, and the thickness is thin. A uniform plating layer is obtained, and the metallic luster of the plating layer is suppressed.

  With the plating layer configured as described above, the surface roughness Rz becomes 2.0 μm or less.

  The nodules formed in the plating layer 30 preferably have an average cross-sectional width of about 0.1 to 2 [mu] m and an average height of about 0.1 to 1 [mu] m. Since the definition and effect of the average cross-sectional width and average height are disclosed in detail in US Pat. No. 5,800,930, description thereof is omitted.

  After forming the coating layer, if necessary, a chromate layer (not shown) can be formed by rust-proofing with a rust-proof solution.

  Hereinafter, a method for manufacturing a patterned copper foil having a mesh whose front and side surfaces are treated with a conductive material according to the present invention will be described in detail.

  First, after the copper foil with the back surface already blackened on the film substrate is prepared and a pattern is formed through an etching process, for the treatment of the front and side surfaces of the copper foil, for example, copper, An electrolytic solution containing cobalt, iron, and nickel is prepared, and the front and side surfaces of the mesh are electroplated under a predetermined temperature, processing time, cathode current density, and current conditions. In this case, it is possible to make the thickness thin and uniform by appropriately setting the conditions of the electrolytic solution and the electrolytic plating.

That is, in order to implement the plating layer having the predetermined thickness and content, the electrolyte is 0.1 to 2.0 g / L of copper, 0.1 to 10.0 g / L of cobalt, 0.1 to 6 of iron. Including 0.0 g / L, nickel 0.02-2.0 g / L, the conditions for the electrolytic treatment at this time are as follows: liquid temperature is 20-50 ° C., pH is 0.5-6, treatment time is 2-30 Second, the cathode current density is set to 0.5 to 20 A / dm ² . More preferably, the electrolytic solution is 0.2 to 1.0 g / L of copper, 3.0 to 9.0 g / L of cobalt, 1.5 to 4.0 g / L of iron, 0.1 to 1.5 g / L of nickel. In this case, the conditions for the electrolytic treatment are such that the liquid temperature is 30 to 40 ° C., the pH is 1 to 3, the treatment time is 5 to 20 seconds, and the cathode current density is ² to 15 A / dm ^2. To do.

  In addition, as a current for forming the plating layer, a general direct current can be used. When a pulse rectifier capable of supplying a pulse current is used, an electrodeposition layer made of uniform and fine particles is formed. It is useful for forming a matte black plating layer in which black particles do not fall out.

  After the above-described plating layer is formed, it is desirable to perform electrolytic chromate rust prevention treatment as necessary according to the time until the user uses it after manufacture.

  As described above, when the front surface and the side surface of the mesh are coated with a conductive material, light reflection by the front surface and the side surface is prevented to ensure favorable visibility, and at the same time, appropriate conductivity and workability are achieved. In particular, in the case of electroplating, complete blackening is achieved.

  When an electroplating layer containing copper-cobalt-iron-nickel is formed, it has excellent oxidation resistance, heat resistance and chemical resistance, and exhibits high peel strength.

  In addition, the electroplating layer has a matte dark black color, black plating particles do not fall out, and low roughness of 2.0 μm or less can be realized, the thickness of the blackening layer is thin, uniform, and transmittance Therefore, it is a copper foil used for a shield material for EMI shielding of a display product such as a PDP, and the visibility problem can be appropriately solved.

  Hereinafter, the present invention will be described in more detail by explaining preferred embodiments of the present invention. However, the present invention is not limited to the following embodiments, and various embodiments can be implemented within the scope of the appended claims. However, the following examples are intended to complete the disclosure of the present invention and make it easier for those skilled in the art to practice the invention.

[Example 1]
In Example 1, a plating surface treatment containing copper-cobalt-iron-nickel was applied to the front and side surfaces of the mesh under the following electrolytic solution composition and electrolytic treatment conditions.

  The composition of the electrolytic solution is as follows: copper (metal copper) 0.4 g / L, cobalt (metal cobalt) 4.0 g / L, iron (metal iron) 2.0 g / L, nickel (metal nickel) 0.2 g / L did.

The electrolytic treatment was performed at a liquid temperature of 35 ° C., a treatment time of 20 seconds, a cathode current density of 10 A / dm ² , and a pH of 1.75 or less.

The ingredient content of the plating layer formed on the front or side of the mesh by such plating treatment, 5 times the measured results, the average value, copper 2.4 mg / m ^2, cobalt 1159.7mg / m ^2, iron 418.5mg / ^{m 2,} was a nickel 10.5 mg / ^{m 2.}

  FIG. 3 is an SEM photograph showing the surface of the copper foil according to Example 1.

[Example 2]
In Example 2, a plating surface treatment containing copper-cobalt-iron-nickel was performed on the front and side surfaces of the mesh under the following electrolytic solution composition and electrolytic treatment conditions.

  The composition of the electrolytic solution is as follows: copper (metallic copper) 0.8 g / L, cobalt (metallic cobalt) 7.0 g / L, iron (metallic iron) 3.0 g / L, nickel (metallic nickel) 1.0 g / L did.

The electrolytic treatment was performed at a liquid temperature of 35 ° C., a treatment time of 10 seconds, a cathode current density of 15 A / dm ² , and a pH of 1.75 or less.

The ingredient content of the plating layer formed on the front or side of the mesh by such plating treatment, 5 times the measured results, the average value, copper 2.8 mg / m ^2, cobalt 1417.6mg / m ^2, iron They were 511.5 mg / m ² and nickel 12.9 mg / m ² .

  FIG. 4 is an SEM photograph showing the surface of the copper foil according to the second embodiment.

  Although the present invention has been described in connection with the preferred embodiments referred to above, various modifications and variations can be made without departing from the spirit and scope of the invention. Accordingly, the appended claims should include such modifications and variations as falling within the spirit of the invention.

It is the schematic which shows the copper foil which has the mesh by which only the conventional back surface was blackened. 1 is a schematic view showing an electromagnetic shielding shield material to which a copper foil having a mesh whose front and side surfaces are treated with a conductive material according to an embodiment of the present invention is attached. It is a SEM photograph about the shape of the processing surface by the present Example 1. FIG. It is a SEM photograph about the shape of the processing surface by the present Example 2.

Explanation of symbols

10 base material 20 mesh 30 back surface 40 front surface 50 side surface 60 conductive substance

Claims (4)

A shielding material for electromagnetic wave shielding comprising a transparent substrate and a copper foil mesh attached in a patterned state to the surface of the substrate,
A thin and uniform conductive coating layer is formed on the front and side surfaces of the copper foil mesh,
The coating layer is a copper - cobalt - iron - nickel (Cu-Co-Fe-Ni ) Tona is, copper 1 mg / ^{m 2} or more, cobalt 1000 mg / ^{m 2} or more, iron 300 mg / ^{m 2} or more, a nickel There is a matte black electroplating layer of Ru der 7 mg / m ² or more, the shield member, wherein a plurality of very fine nodules for implementing a low-roughness on the surface thereof is formed .   2. The electromagnetic shielding material according to claim 1, wherein the coating layer has a thickness of 1 μm or less and a surface roughness Rz of 2 μm or less. The coating layer is an electromagnetic wave according to claim 1, characterized in that it comprises copper 1 to 4 mg / ^{m 2,} cobalt 1000~2000mg / ^{m 2,} the iron 300 to 600 mg / ^{m 2} and nickel 7~15mg / ^{m 2} Shielding material for shielding. ^2. The electromagnetic wave according to claim 1, wherein the coating layer includes copper ^{2 to 3} mg / m ² , cobalt 1100 to 1500 mg / m ² , iron 400 to 550 mg / m ^2, and nickel 10 to 13 mg / m ^2. Shielding material for shielding.

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