KR20090116463A - Display optical filter using electroconducting layer and preparation thereof - Google Patents

Abstract

PURPOSE: A display optical filter and a manufacturing method thereof are provided to reduce a moire error at an effective screen part by more increasing a mesh width of an edge part of a conductive mesh layer than a mesh width of the effective screen part. CONSTITUTION: A display optical filter includes a conductive mesh layer. The conductive mesh layer has an effective screen part(1) and an edge part(2). A display screen is displayed on the effective screen part. The edge part is grounded with a display main body. A mesh pattern of the edge part and a mesh pattern of the effective screen part are continuously formed. The mesh pattern of the edge part and the mesh pattern of the effective screen part are formed by a printing process at the same time. A mesh width of the edge part is 1.3~5 times of a mesh width of the effective screen part. The mesh width of the effective screen part is 10~30um.

Description

Display optical filter using conductive mesh layer and manufacturing method thereof {DISPLAY OPTICAL FILTER USING ELECTROCONDUCTING LAYER AND PREPARATION THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display optical filter using a conductive mesh layer and a method of manufacturing the same. Specifically, the present invention relates to a display optical filter and a method of manufacturing the same. The present invention relates to a display optical filter using a conductive mesh layer having excellent image quality characteristics and the like and a manufacturing method thereof.

PDP (Plasma Display Panel) is not only to prevent harmful effects of human body and malfunction of precision instruments by electromagnetic waves and near infrared rays generated from it, but also to reduce surface reflection and improve color purity. The optical filter which has a prevention and color purity improvement function is employ | adopted.

In particular, since PDP generates a large amount of electromagnetic waves compared with other displays such as CRT or LCD, stronger electromagnetic shielding property is required. In general, the electromagnetic shielding performance may be expressed by sheet resistance. The electromagnetic shielding material used in the optical filter for PDP has a sheet resistance of about 2.5 Ω / □ or less, generally 1.5 Ω / □ or less, preferably 0.8 Ω / □ or less. Not only have to have, but also need high conductivity to be used as home TV.

In order to meet these requirements, various materials and methods have been proposed that can simultaneously achieve high transparency with excellent electromagnetic shielding using metal mesh.

For example, Japanese Patent Laid-Open No. 2003-46293 or 2003-23290 uses a photolithography method after attaching a copper foil on a PET film in an optical filter for PDP that is conventionally employed to block harmful electromagnetic waves. A method of forming a fine pattern through etching is disclosed. However, this method not only has the disadvantage of complicated manufacturing process and high manufacturing cost, but also the fiber mesh fabricated by patterning the metal fiber or the metal-coated conductive organic fiber on the film substrate has a limitation of the mesh line width and the aperture ratio There is a problem that the display is not sufficiently represented by the display is low and transmittance is low.

In Japanese Patent Laid-Open Nos. Hei 5-16581 and Hei 10-72676, a transparent resin layer is formed on a transparent substrate such as polycarbonate, and an electroless copper plating treatment is performed thereon, followed by etching through a photolithography process. A method for producing an electromagnetic wave shielding filter for forming a mesh pattern is disclosed. However, this method has a problem in that the metal layer is wasted because etching is performed after the metal plating layer is formed on the entire surface of the substrate.

Unlike the electromagnetic shielding material having such a mesh pattern, there is also a conductive film type electromagnetic shielding material obtained by alternately coating a metal thin film (eg, Ag) and a dielectric layer with a multilayer thin film by using a dry coating method such as sputtering on the entire surface of the transparent substrate. This type of electromagnetic shielding film is insufficient in conductivity and is used only for applications requiring low electromagnetic shielding properties, and it is difficult to use in home TVs.

As described above, the various electromagnetic wave blocking members mentioned above use a separate film substrate for forming the electromagnetic wave shielding layer together with the disadvantage that the manufacturing process is complicated and the amount of raw materials lost during the manufacturing process is large. In this case, there is a problem in that a pressure-sensitive adhesive layer capable of attaching the film is required separately. Particularly, in the case of the conventional electromagnetic wave shielding layer formed of a mesh type, since the haze is high and it is difficult to realize a clear image quality, an additional transparent process using a separate transparent resin layer or adhesive layer is necessary to be used as a filter. There is this.

In order to solve these problems, in recent years, the development of the technology which can simply form the metal mesh on the glass or film substrate by the printing method has been attempted. In particular, conductive particles made of silver, copper, nickel, or a compound thereof are used as a main raw material, and an organic binder and a solvent are mixed therein to prepare a conductive paste, and a mesh pattern is simply formed on a glass or transparent substrate by printing or the like. Forming methods have been proposed (see Japanese Patent Application No. 2001-208111 and Korean Patent Application No. 2006-0110423).

The conductive mesh member formed in this way has the advantage that the mesh pattern can be easily formed over the entire surface of the filter. However, when a mesh pattern having a size that can implement low resistance while maintaining high visible light transmittance is formed on the front surface of the substrate, the display body Since the ground of the part electrically connected to the inside is difficult to be properly formed, the charge generated when the electromagnetic wave is absorbed may not occur quickly through the ground.

Therefore, in order to solve the above problem, the electromagnetic shielding ability may be relatively inferior to the surface resistance, but the surface resistance of the conductive mesh using electroless plating or selective plating method such as electrolytic plating method after printing the mesh layer is performed. It is possible to use a method of improving the electromagnetic shielding ability by providing a separate conduction portion by using a silver paste or a conductive tape at the position of the mesh member to be connected to the mechanism to connect to the display main body and lowering.

However, this also has disadvantages such as the need for expensive materials and separate processing.

As described above, the electromagnetic wave shielding film formed by the conventional printing method has the same line width as the entire surface of the mesh layer or has a conductive connection part completely covered by the edge portion, but in the case of the former, the overall mesh line width in order to maintain stable electromagnetic wave blocking ability Is relatively thick, the tolerance of the free bias angle in the moire is relatively narrow, and the transmittance is low. In the latter case, an additional process for forming a separate grounding part is required and There is a problem that the amount of material used increases the manufacturing cost.

Accordingly, an object of the present invention is to provide a display optical filter that not only has a high transmittance but also improves the grounding ability with a display main body such as a PDP, so as to realize a safe electromagnetic shielding ability and reduce moiré defects in an effective screen portion. It is.

In the present invention to achieve the above object,

And a conductive mesh layer including an effective screen portion on which the display screen is displayed and a border portion which is grounded with the display main body, wherein the mesh pattern of the edge portion of the conductive mesh layer and the mesh pattern of the effective screen portion are formed in a continuous form without disconnection. The mesh line width of the edge portion is 1.3 to 5 times wider than the mesh line width of the effective screen portion provides a display optical filter.

This invention also provides the manufacturing method of the said display optical filter.

Hereinafter, the present invention will be described in more detail.

In the display optical filter of the present invention, the entire surface of the conductive mesh layer is formed in the same line width (see FIG. 6), or the edge portion of the conductive mesh layer is formed as a separate frame portion that does not transmit light for grounding with the display body. Unlike the sheet, as shown in FIG. 1, the edge portion of the mesh layer is also formed in a mesh shape, wherein the mesh line width at the edge portion is different from the mesh line width of the effective screen portion on which the display image is displayed.

The conductive mesh layer according to the present invention is formed on one side of the transparent substrate by using a conductive paste composition as described in Korean Patent Application No. 2007-0021181 made of a transparent polymer resin, a conductive metal powder, a black pigment, a dispersant, or the like. It can be obtained by directly forming the mesh pattern by a conventional printing process or a film transfer process as described in Japanese Patent Application No. 2002-275422.

In the mesh pattern, the shape of the opening may vary according to the display specification. For example, the shape of the opening may be a polygon, such as a triangle, a rectangle, a hexagon, an octagon, a dove, or a curved line. It can be circular, elliptical, annular, etc., and forms the mesh form of the effective screen portion and the edge portion in a continuous form without a single line, but forms the mesh line width of the edge portion different from the mesh line width of the effective screen portion.

Specifically, the electromagnetic shielding front plate of the present invention forms the mesh line width of the edge portion which is grounded with the display main body 1.3 to 5 times, preferably 1.5 to 3 times larger than the mesh line width in the effective screen. If the mesh line width of the edge of the display body and the grounded area is less than 1.3 times the mesh line width of the effective screen, the surface resistance of the effective screen may not be low enough. If this increase is greater than 5 times, the surface resistance is lowered and the ground can be stably grounded with the display apparatus, but the manufacturing cost increases due to the high consumption of the conductive paste used to form the mesh.

In the conductive mesh layer used in the display optical filter of the present invention, the mesh opening ratio of the edge portion is about 30 to 90% smaller than the opening ratio in the effective screen, and the surface resistance of the edge portion is 30 compared to the surface resistance measured in the effective screen. To 70% as low.

In addition, the conductive mesh layer used in the display optical filter of the present invention has a mesh line width of the effective screen portion where the screen of the display body is visible, in the range of 10 to 35 μm, preferably in the range of 10 to 30 μm, particularly preferably in the range of 15 to 27 μm. It is in the range of µm, which means that if the mesh layer line width of the effective screen portion is less than 10 µm, the surface resistance of the formed pattern is increased to reduce the electromagnetic shielding performance, and if it exceeds 35 µm, the aperture ratio is lowered and sufficient transmittance of the transparent substrate (e.g. glass) This is because there is a disadvantage in that light loss from the panel is increased and the risk of moiré increases. In addition, when the mesh line width of the effective screen portion is out of the above range, the transmittance of the electromagnetic wave shielding film is lowered, resulting in a narrow color adjustment range for manufacturing the optical filter, and it is difficult to implement a desired color in the filter assembly.

In the present invention, the surface resistance in the effective screen portion of the electromagnetic shielding layer is 1.5 Ω / □ or less, preferably in the range of 0.15 to 1.5 Ω / □, and the surface resistance of the edge portion is 0.5 Ω / □ or less, preferably 0.10 To 0.5 mW / square.

In the electromagnetic wave shielding film according to the present invention, the edge portion of the thick mesh line width may be positioned within 0 to 50 mm from the edge of the transparent substrate such as glass, and may be formed to have a width of 5 to 30 mm. As shown in FIG. 2, only two sides of the transparent substrate may form a thick edge portion, and if necessary, as shown in FIG. 3, only the portion where the ground member of the structure for grounding with the display main body is located. It is also possible to thicken it.

Mesh layers having different line widths between the edge portion and the effective screen portion may be formed simultaneously using a printing method such as a conventional gravure offset printing process.

In the present invention, as the transparent substrate for forming the transparent mesh layer can be used a conventional transparent substrate used in the manufacture of electromagnetic wave shielding sheet, for example, glass or a transparent resin film such as polyester, polycarbonate, etc. Can be mentioned.

As an electroconductive metal substance contained in the said electroconductive paste composition, 1 or more types chosen from the group which consists of silver, copper, nickel, and these alloys are mentioned.

In addition, the glass powder powder used in the present invention may be a conventional glass powder powder as described in Japanese Patent Application No. 2003-282833, but consisting of a compound that does not contain lead to prohibit the use of environmentally harmful substances. It is preferable to use.

By uniformly laminating one or two functional films on the prepared conductive mesh layer, the display optical filter of the present invention as shown in FIGS. 4 and 5 can be produced.

The functional film layer may have a conventional structure as a conventional functional layer known in the art, and examples thereof include an antireflection film, a near infrared ray blocking film, and a selective light absorbing film. In the display optical filter of the present invention, the anti-reflection layer and the near infrared ray blocking / selective light absorbing layer may be formed on both sides of one transparent substrate, respectively, and the near infrared ray blocking / selective light absorbing layer is incorporated by incorporating the near infrared ray blocking and the selective absorbing dye into the adhesive. Can be obtained.

The display optical filter of the present invention may have an antireflective layer on the outermost portion as shown in FIGS. 4 and 5, and the conductive mesh layer may be located outwardly toward the display body and may have an exposed structure. In addition, a conductive tape may be applied to the edge portion for better grounding with the display.

The display optical filter manufactured according to the present invention has excellent haze of about 1 to 4% without going through a separate transparent process, and has a light transmittance in the range of 380 to 780 nm in the range of 30 to 60%.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

The display optical filter manufactured according to the present invention includes a mesh pattern of the effective screen portion in which the display image of the conductive mesh layer is visible and a mesh pattern of the edge portion electrically grounded with the display main body in a continuous form without disconnection. Since the mesh line width and the mesh line width of the effective screen portion are different, the image quality characteristics such as moiré, transmittance, and haze in the effective screen are excellent, and at the same time, the electrical contact with the display main body is improved, and the electromagnetic wave blocking ability is excellent.

Example 1:

A conductive paste resin composition of an electromagnetic wave shielding layer was prepared in the following manner.

As transparent polymer resin, 15 weight% of organic vehicles (weight average molecular weight 20,000) superposed | polymerized in the state mixed with methacrylic acid (MA) and methyl (meth) acrylate (MMA); As a resin for improving dispersibility, 10 wt% of an epoxy acrylate organic vehicle in an oligomer state; As a conductive metal powder, 67 weight% of silver powder; As a black pigment component, 3.5 weight% of cobalt oxides; As a glass powder, bismuth oxide-boron oxide-silicon oxide _{(Bi 2 O 3 -B 2 O} 3 -SiO 2) based mixture of 3.5% by weight; And 1% by weight of an organic dispersant containing an amine group (DS-101, manufactured by Sannovco, Korea) at room temperature, mixed and stirred, and finally milled with a 3-roll mill to produce a desired printing paste composition (ie, an electromagnetic shielding layer). Forming composition).

Subsequently, using the obtained paste composition, one side of the semi-reinforced transparent glass was uniformly patterned by gravure offset printing in a manner similar to that described in Japanese Patent Application No. 2001-208111 to form an electromagnetic wave shielding layer. Specifically, the printing paste composition was applied to a gravure plate on which a predetermined pattern was formed, and then about doctored using a blade, and then the composition of the gravure plate was transferred to a blanket (off process). At this time, the line width of the mesh pattern carved into the gravure was carved 80% thicker than the pattern line width of the effective screen portion, and the patterned area of the gravure plate was the same as the 42-inch glass size. The long side was 984 mm and the short side was 584 mm. More specifically, the pattern line width of the effective screen portion of the gravure plate is 30 μm, the line spacing (pitch) is 300 μm, and the bias angle is 47 ° when observed after printing on the final glass. The shape was made to be square. In addition, the edge portion has a pattern line width of 54 占 퐉, and other line spacing, bias angle, and shape of the opening portion are the same as the effective screen portion. The edge part was reflected when engraving a gravure plate so that it may be formed by 50 cm from the edge part on the four sides of glass substrate similarly. The pattern-engraved gravure plate was filled with the printing composition and transferred to the blanket by applying a constant pressure of about 5 Kgf, and transferred to the panel glass substrate by applying a uniform pressure of about 3 Kgf to the pattern on the blanket as well.

The pattern of the printing composition transferred to the substrate evaporated the solvents using a drying furnace, and removed the impurities adversely affecting the electrical conductivity through the firing process to form the electromagnetic shielding layer. The line width of the conductive mesh which passed through the baking process was 18 µm in the effective screen portion and 40 µm in the edge portion.

Next, the display optical filter as shown in FIG. 4 was produced using the obtained conductive mesh layer and a functional film.

As schematically shown in FIG. 4, the functional film used together with the electromagnetic wave shielding sheet in the manufacture of the display optical filter includes an antireflective layer 31, a near-infrared shielding and an optional light absorbing layer 41, and adhesive layers 33 and 43. ), And the like.

The antireflection film 31 was obtained by sequentially laminating a hard coat layer, a zirconium oxide high refractive film, and a fluorosiloxane low refractive film on a conventional biaxially stretched polyester (PET) film 32 by a wet coating method. On the other hand, the near-infrared blocking and selective light absorbing film 41 completely dissolved 300 g of poly (methyl methacrylate) in 1000 ml of methyl ethyl ketone (MEK), and then added 100 mg of octaphenyl tetraazapopyrine and IFG022 (Japan). Explosives) 150 mg was added to dissolve the solution, and then a solution obtained by slowly adding 120 mg of acridine orange (Aldrich Chemical Co., Ltd.) in 50 ml of isopropyl alcohol was added to a separate polyester (PET) film 42. It was obtained by coating (dry thickness: about 5 μm) by the wet coating method using roll coating.

Subsequently, an acrylic transparent pressure-sensitive adhesive was continuously coated on the polyester film coated with a silicone release layer by a comma coating method, and after release of hot air drying, a release film having a different peeling force was laminated on the coated surface to form a transparent adhesive formed of a double-sided release film. The membrane was obtained in roll form.

Each of the functional films 30 and 40 on which the antireflective layer 31 and the near-infrared cut-off and selective light-absorbing film 41 formed were applied to the adhesive layer by applying a constant pressure (3 kgf / m ² ) while peeling off the release film of the transparent adhesive film. Through the process of forming the obtained anti-reflection film and the functional film of the selective light absorption function with the pressure-sensitive adhesive was obtained. The two functional films thus obtained are uniformly attached at a constant pressure (3 kgf / m ² ) using a roll-to-roll laminating process to form a composite film, and then uniformly attached to the electromagnetic wave shielding front film to display an optical filter for display. The assembly was prepared.

Example 2:

In the gravure plate, the line width was sculpted at 54 μm on only the two sides of the edge portion, and the two sides on the short side were formed in the same manner as the effective screen portion (see FIG. 2). An optical filter assembly for display was prepared.

Comparative Example 1:

By adjusting the shape of the gravure plate pattern, the same process as in Example 1 was carried out except that the entire surface of the electromagnetic wave shielding front film was manufactured in the same width without a distinction between the edge portion and the effective screen portion with a line width of 20 μm and a pitch of 300 μm. An optical filter assembly for display was prepared.

Comparative Example 2:

By adjusting the shape of the gravure plate pattern, the same process as in Example 1 was performed, except that the entire surface of the electromagnetic wave shielding front film was manufactured in the same width without a distinction between the edge portion and the effective screen portion with a line width of 34 μm and a pitch of 300 μm. An optical filter assembly for display was prepared.

Characteristic test

For the optical filter assembly for display manufactured in Examples 1 and 2, and Comparative Examples 1 and 2, a four-point probe consisting of four equally spaced probes in accordance with the standard of ASTM D257 was used to The surface resistance of the effective screen portion was measured, five points were measured uniformly, and the average value thereof was described. In addition, the fabricated optical filter was mounted on a plasma display (PDP) TV to investigate EMI blocking ability under the same conditions. The PDP TV used was W2 model of Samsung SDI Co., Ltd., 3M chamber was used for EMI measurement, and for more accurate evaluation, it was requested by IST, a national authorized testing agency for electronic products, to reflect the Class B standard. The radiation dose was measured. In addition, using a spectrometer (model name: Nippon Denshoku NDH-5000), the transmittances of the edge portion and the effective screen portion were measured, and the results are shown in Table 1 below.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Effective screen surface resistance (Ω / □) 0.66 0.64 0.62 0.30 Edge Resistance (Ω / □) 0.20 (Short side) 0.65 (long side) 0.21 0.61 0.33 EMI blocking capability ◎ ○ △ ◎ Effective Screen Transmittance (%) 48 48 48 45 Moire none none none has exist Paste Consumption per Sheet usually usually usually plenty ◎: Very good, ○: Excellent, △: Normal

As shown in Table 1, in the case of the optical filter for a display according to the present invention manufactured by adjusting the mesh line width of the edge portion of the conductive mesh layer formed by using the gravure offset method slightly thicker than the mesh line width of the effective screen portion (Example 1 And 2), it can be seen that not only the EMI shielding ability is excellent but also excellent image quality with less image defects such as moiré. In addition, when the line width of the edge portion is thickened only in the two long side directions, and the mesh is formed with the same line width as the effective screen portion in the two short side directions (Example 2), when the line width is formed on all four surfaces thick (Example EMI shielding ability is somewhat lower than 1), but EMI shielding ability is superior to general front mesh state (Comparative Example 1). In addition, in the case of forming a mesh with a thick line width over the entire glass surface to achieve low resistance (Comparative Example 2), the sheet resistance is lowered to improve the EMI shielding ability, but the moire was observed, and the amount of paste composition required was increased. The filter transmittance was also lowered.

Although the embodiments and comparative examples of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing its technical spirit or essential features. I can understand that it can be.

1 to 3 are conceptual views of one example of the conductive mesh layer used in the optical filter for display according to the present invention.

4 and 5 are cross-sectional views showing the layer structure of the optical filter for display according to the present invention.

6 is a conceptual diagram of a conventional front mesh type electromagnetic shielding sheet.

<Short description of drawing symbols>

1, 10: effective screen portion

2, 20: border

30, 40: functional film

31, 61: antireflection film

32, 42, 62: base film

33, 43, 64: transparent adhesive layer

41, 63: near infrared shielding and selective light absorbing layer

50, 500: electromagnetic shielding glass

51, 510: conductive mesh layer

Claims (19)

A conductive mesh layer including an effective screen portion on which a display screen is displayed and an edge portion which is grounded with the display body; Display optical filter, characterized in that the mesh pattern of the edge portion of the conductive mesh layer and the mesh pattern of the effective screen portion is formed in a continuous form without disconnection, the mesh line width of the edge portion is 1.3 to 5 times wider than the mesh line width of the effective screen portion. . The display optical filter of claim 1, wherein a mesh line width of two or four sides of the edge portion of the conductive mesh layer is larger than the mesh line width of the effective screen portion. The display optical filter according to claim 1, wherein the mesh layer of the edge portion is formed 5 to 30 mm wide within the range of 0 to 50 mm from the edge of the transparent substrate. The display optical filter of claim 1, wherein the mesh layer of the edge portion and the mesh layer of the effective screen portion are simultaneously formed through a printing process. The display optical filter according to claim 1, wherein the surface resistance of the effective screen portion of the conductive mesh layer is 0.15 to 1.5? / Sq. The display optical filter according to claim 1, wherein the surface resistance of the edge portion of the conductive mesh layer is 0.05 to 0.5 Ω / square or less. The display optical filter of claim 1, wherein a mesh line width of an effective screen portion of the conductive mesh layer is 10 to 30 μm. The manufacturing method of the display optical filter of Claim 1 including forming a conductive mesh layer in a printing process using a conductive paste composition on one surface of a transparent base material. The method of claim 8, wherein the conductive paste composition comprises a transparent polymer resin, a conductive metal powder, a black pigment and a dispersant. 10. The method of claim 9, wherein the conductive metal powder is at least one selected from the group consisting of silver, copper, nickel and alloys thereof. The display optical filter of claim 1, wherein the display optical filter is manufactured by laminating one or two functional films on a conductive mesh layer. The display optical filter according to claim 11, wherein the functional film comprises at least one member selected from the group consisting of an antireflection layer, a near infrared ray blocking layer and a selective light absorbing layer. The display optical filter according to claim 11 or 12, wherein the haze is 1 to 4% without undergoing a separate transparent process. The display optical filter according to claim 12, wherein the antireflection layer is located at the outermost portion of the filter. 13. The display optical filter according to claim 12, wherein the antireflection layer, the near infrared blocking and the optional light absorbing layer are formed on both sides of one transparent substrate. The display optical filter according to claim 12, wherein the near-infrared blocking and selective absorbing layer is formed by incorporating the near-infrared blocking and selective absorbing pigment into the pressure-sensitive adhesive. The display optical filter according to claim 11 or 12, wherein the conductive mesh layer is located at the outermost side toward the display body and has an exposed structure. The display optical filter according to claim 11 or 12, wherein the conductive mesh layer faces the viewer and has a structure surrounding the mesh layer rim with conductive tape for grounding with the display. 13. Display optical filter according to claim 11 or 12, wherein the light transmittance for the 380-780 nm wavelength range is in the range of 30-60%.

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