WO2008111757A1

WO2008111757A1 - Black paste composition having conductivity property, filter for shielding electromagnetic interference and display device comprising the same}

Info

Publication number: WO2008111757A1
Application number: PCT/KR2008/001255
Authority: WO
Inventors: Bong-Gi Kim; Seung-Hun Jeon; Na-Young Baek; Jong-Wook Lee; Chan-Seok Park; Kyung-Rock Byun; Chan-Min Jung
Original assignee: Dongjin Semichem Co., Ltd
Priority date: 2007-03-09
Filing date: 2008-03-05
Publication date: 2008-09-18

Abstract

The present invention relates to a black conductive paste composition, a filter for shielding electromagnetic interference and a display device comprising the same. The composition comprises includes a) an acrylate resin, b) a solvent, c) a glass powder, d) a conductive metal, e) a black pigment, and f) a dispersing agent that is at least one selected from the group consisting of a modified acrylic block copolymer, an alkylol ammonium salt polymer, a block copolymer including a basic pigment affinity group, an acrylic block copolymer, a fluorinated alkyl oligomer, a polyether modified dimethylsiloxane copolymer and a modified polyurethane. The paste composition can be applied for manufacturing a filter for shielding electromagnetic interference, particularly according to a gravure offset printing method.

Description

TITLE OF THE INVENTION

BLACK PASTE COMPOSITION HAVING CONDUCTIVITY PROPERTY, FILTER FOR SHIELDING ELECTROMAGNETIC INTERFERENCE AND DISPLAY DEVICE COMPRISING THE SAME

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a black conductive paste composition, a filter for shielding electromagnetic interference, and a display device comprising the same. The composition is applied for a filter of a display device, and reduces reflection of outer light and improves the contrast ratio of the display device.

(b) Description of the Related Art

Recently, various kinds of display devices have been developed. For example, a plasma display device (PDP), a liquid crystal display device (LCD), an organic light emission display device (OLED), etc. have been developed. Since these display devices have a small thickness and a low weight, they are used in many products that are necessary for displaying images.

Electromagnetic interference (EMI) is emitted from many electric elements included in the display device. The electromagnetic interference causes malfunction of the display device and harm to a human body. Therefore, a filter for shielding electromagnetic interference is attached to the display device for shielding electromagnetic interference.

In the prior art, a paste composition for a filter for shielding EMI generally includes an acrylate resin, a solvent, a conductive metal, a black pigment, etc. However, most conventional paste compositions are applied to a resin substrate by directly adhering them thereto with an adhesive, or they need an additional coating layer on the resin substrate, which causes difficulty in reducing the thickness of the filter. Further, polymers derived from the adhesive and additional coating layer disadvantageously remain in the filter. As a result, a paste composition that is useful for glass substrate is required. For example, Korean publication no. 2002-82744 discloses a conductive paste including binder resins such as an acrylate resin, a glass powder with a softening point, a black pigment, metal powders such as gold, silver or nickel, and a solvent. It also discloses a plate for shielding electromagnetic interference for a display device such as a plasma display device by coating the conductive paste on a glass substrate in a pattern, and baking it.

However, when the conventional filter for shielding electromagnetic interference is applied to a display device such as a plasma display panel, it does not sufficiently reduce the reflection of outer light, and is thereby deficient in terms of contrast ratio of the display device. In addition, because other components cannot be sufficiently dispersed in the binder resin, a uniform shielding capacity of electromagnetic interference and proper optical properties cannot be obtained.

SUMMARY OF THE INVENTION The present invention provides a black conductive paste composition for a filter for shielding electromagnetic interference used for a display device, showing uniform shielding capacity of electromagnetic interference and proper optical properties due to improved dispersibility of the components.

In another aspect, the present invention provides a black conductive paste composition for a filter for shielding electromagnetic interference used for a display device with reduced reflection of outer light and improved contrast.

In a third aspect, the present invention provides a filter for shielding electromagnetic interference that is manufactured by printing the paste composition on a glass substrate and sintering it. In a fourth aspect, the present invention provides a display device with a shielding member for electromagnetic interference that is manufactured by using the paste composition.

The black conductive paste composition of the present invention includes a) an acrylate resin, b) a solvent, c) a glass powder, d) a conductive metal, e) a black pigment, and f) a dispersing agent selected from the group consisting of a modified acrylic block copolymer, an alkylol ammonium salt polymer, a block copolymer including a basic pigment affinity group, an acrylic block copolymer, a fluorinated alkyl oligomer, a polyether modified dimethylsiloxane copolymer, and a modified polyurethan. The paste composition is applied for a filter for shielding electromagnetic interference used for a display device such as a plasma display panel, and preferably, the paste composition is printed on a glass substrate (for example, by offset printing) and sintered to produce a shielding filter for a display device.

The paste composition includes a) 5 to 15 parts by weight of an acrylate resin, b) 5 to 15 parts by weight of a solvent, c) 1 to 10 parts by weight of a glass powder, d) 50 to 90 parts by weight of a conductive metal, e) 1 to 10 parts by weight of a black pigment, and f) 0.05 to 1.0 parts by weight of a dispersing agent.

In addition, the filter for shielding electromagnetic interference includes a glass substrate and a shielding member formed on the glass substrate in a mesh shape, and the shielding member is manufactured by printing the black conductive paste composition on the glass substrate and sintering it.

Furthermore, the display device of the present invention includes a glass substrate, a shielding member formed on the glass substrate in a mesh-shaped, and a display panel that displays an image and is opposed to the glass substrate, and the shielding member is configured to shield electromagnetic interference emitted from the display panel and is manufactured by printing the black conductive paste composition on the glass substrate and sintering it.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a filter for shielding electromagnetic interference according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view along a line II-II of FIG. 1.

FIG. 3 is a schematic view illustrating a manufacturing method of the filter for shielding electromagnetic interference of FIG. 1.

FIG. 4 is a schematic perspective view of the display device provided with the filter for shielding electromagnetic interference of FIG. 1. FIG. 5 is a partial cross-sectional view along a line V-V of FIG. 4. FIGs. 6 to 8 are microphotographs of a mesh-shaped pattern formed in the shielding filters of Examples 6 to 7 and Comparative Example 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will be explained in more detail with reference to the following drawings.

The present invention provides a black conductive paste composition for a filter for shielding electromagnetic interference used for a display device, and the filter reduces the reflection of outer light and improves the contrast ratio of the display device.

Because the black conductive paste composition includes a specific dispersing agent, the dispersion capability of other components such as a glass powder, a conductive metal, a black pigment, etc. in an acrylate resin is improved. Thus, the filter for shielding electromagnetic interference that is manufactured by printing the black conductive paste composition on the glass substrate and sintering it shows uniform shielding capacity of electromagnetic interference and proper optical properties, and can thereby be used for a display device such as a PDP.

Surprisingly, the experimental results of the present inventors showed that because of the specific dispersing agent used in the black conductive paste composition, the filter obtained from the paste composition reduces the reflection of outer light and improves the contrast ratio of the display device.

In addition, the black pigment and glass powder are contained in the black conductive paste composition, and thus the composition may be directly printed on the glass substrate to obtain a clear pattern of interest, and the organic material included in the pattern can be easily removed. Therefore, the black conductive paste composition is preferably applied to the glass substrate for a display device as a printing composition, thereby advantageously reducing the thickness of the shielding filter for a display device.

In the paste composition of the present invention, the acrylate resin is at least one polymer selected from the group consisting of methyl acrylate (MA), butyl methacrylate (BM), hydroxyethyl methacrylate (HEMA), methylmethacrylate (MMA), ethyl acrylate (EA), ethylhexyl acrylate, nonyl acrylate, and methacrylates thereof. Preferably, the acrylate resin is a copolymer obtained by copolymerizing methyl acrylate (MA), butyl methacrylate (BM), hydroxyethyl methacrylate (HEMA), and methylmethacrylate (MMA) in a mixing ratio 10 to 30 : 30 to 60 : 10 to 20 : 10 to 20 by weight. The acrylate resin is not limited thereto, and includes any acrylate resin that is known as a binder resin for a conductive paste composition for a shielding filter.

The acrylate resin causes the other components such as the glass powder, the conductive metal, the black pigment, etc., be dispersed homogeneously in the black conductive paste composition, thereby providing the shielding filer obtained from the black conductive paste composition with uniform electromagnetic interference and optical properties.

The acrylate resin has a weight average molecular weight of 5000 to 100,000, and preferably of, 5000 to 60,000. When the weight average molecular weight is lower than 5000, the low glass transition temperature of the polymer increases the fluidity of the polymer, thereby making it difficult to transfer the pattern from a gravure groove to a blanket in the printing process (for example, in gravure offset printing) of the black conductive paste composition. If the weight average molecular weight is higher than 100,000, excessive elasticity of the polymer causes a difficulty in injecting the paste composition into the gravure grooves.

In addition, the amount of acrylate resin is preferably 5 to 15 parts by weight with respect to the total paste composition. When the amount is less than 5 parts by weight, the reduced elasticity of the paste composition causes a printing problem. If it is higher than 15 parts by weight, it is possible to increase the electrical resistance of a pattern formed by the paste composition.

The solvent in the black conductive paste composition is contained in an amount of 5 to 15 parts by weight with respect to the paste composition. When the amount is less than 5 parts by weight, the increased drying rate of the paste composition makes continuous printing difficult. When it is higher than 15 parts by weight, the reduced viscosity of the paste composition causes deteriorated printability. Any solvent that has been generally used in a paste composition for a shielding filter can be used for the present invention. Preferably, the solvent includes at least one of a high boiling point solvent having a boiling point of 200 ^°C or higher, and at least one of a low boiling solvent having a boiling point lower than 200 ^"C . The high boiling point solvent and the low boiling point solvent are used in combination, and thus the viscosity and fluidity of the paste composition are maintained at a proper level. Thus, in the printing process of the paste composition on the glass substrate, the paste composition can be easily transferred to a pattern, and prevention of pattern spreading improves the straightness of the pattern. Examples of the high boiling point solvent are at least one selected from the group consisting of gammabutyrolactone, butylcarbitolacetate, carbitol, methoxymethyletherpropionate, and terpineol, and further include any solvent that has a boiling point of 200 ^°C or higher and can be used for a paste composition for a shielding filter. In addition, examples of the low boiling point solvent are at least one selected from the group consisting of propyleneglycol monomethylether, diethyleneglycol methylethylether, diethyleneglycol monomethylether, dipropyleneglycol monomethylether, propyleneglycol monomethyletherpropionate, ethyletherpropionate, propyleneglycol monomethyletheracetate, methylethylketone, and ethyllactate, and further include any solvent that has a boiling point of lower than 200 ^°C and can be used for a paste composition for a shielding filter.

The solvent includes 12 to 88 wt% of the high boiling point solvent and 12 to 88 wt% of the low boiling point solvent. When the high boiling point solvent is contained in an amount of less than 12 wt% and the amount of the low boiling point solvent is excessively high, the reduction rate of the fluidity of the paste composition is excessively high, and the transfer from the paste composition to pattern is not easily performed. When the high boiling point solvent is contained in an amount of higher than 88 wt%, it is difficult to suppress the fluidity of the paste composition, thereby causing serious pattern spreading and a reduction the straightness of the pattern. The glass powder of the present invention includes a Pb-based glass powder and a Pb-free glass powder, and the Pb-free glass powder is preferably used for the temperature of removing organic materials and improving the adhesiveness of the pattern to the glass substrate in considering environmental regulations. Examples of Pb- free glass powders are a Bi-based glass powder such as a BΪ₂θ₃-based glass powder. In addition, a colored glass powder can be obtained by adding a black or other color pigment in the manufacturing process of the glass powder, or a glass powder including a colored component such as V₂O₅ may be used.

The amount of the glass powder is 1 to 10 parts by weight and preferably 2 to 7 parts by weight with respect to the total paste composition. When the amount is less than 1 part by weight, the adhesiveness of the paste composition to the glass substrate is reduced. When the amount is higher than 10 parts by weight, the electrical resistance of the pattern manufactured from the paste composition increases, thereby lowering the shielding capacity for electromagnetic interference.

The conductive metal may be any metal that is used for an electrode, and more specifically, is at least one selected from the group consisting of silver, copper, nickel, and alloys thereof.

The amount of the conductive metal is 50 to 90 parts by weight with respect to the total paste composition. When the amount is higher than 90 parts by weight, the increased viscosity of the paste composition and difficulty of dispersion reduces the printing capacity. When the amount is less than 50 parts by weight, the increased electrical resistance of the pattern obtained from the paste composition deteriorates the shielding of electromagnetic interference which is required for a display device.

The average particle diameter of the conductive metal is 0.3~30μm, more preferably 0.5~10μm, and most preferably 0.5~5jtan. When the average particle diameter is less than 0.3μm, low dispersion of the conductive metal and high viscosity or gellation of the paste composition deteriorates the printing properties, thereby making it difficult to obtain a good pattern through the printing of the paste composition. When the particle size is larger than 30μm, the metal powder cannot be homogeneously filled in a pattern, thereby causing difficulty in obtaining uniform shielding capacity and a shielding filter with a preferred pattern due to occurrence of holes in the pattern. If the average particle diameter of the metal powder is 0.3~30/zm, more preferably 0.5-1 Oμm, and most preferably 0.5~5μm, it improves the printing capacity and shielding capacity of the paste composition, and prevents holes from being formed in the pattern.

The black pigment reduces the reflection of outer light and improves the contrast ratio and includes a cobalt-based compound, a copper-based compound, a ruthenium-based compound, a manganese-based compound, a nickel-based compound, a chromium-based compound, or a steel-based compound, and more preferably includes cobalt-based compounds. Preferably, an auxiliary pigment such as a copper-based compound, a ruthenium-based compound, a manganese-based compound, a nickel- based compound, a chromium-based compound, or a steel-based compound can be added to the black pigment including the cobalt-based compound to improve the black degree.

The amount of black pigment is 1 to 10 parts by weight, and preferably 2 to 7 parts by weight with respect to the total paste composition. When the amount is less than 1 part by weight, the contrast ratio cannot be sufficiently improved. When the amount is higher than 10 parts by weight, the increased electrical resistance of the pattern may deteriorate the shielding capacity of electromagnetic interference.

The black conductive paste composition includes a specific dispersing agent, which is at least one selected from the group consisting of a modified acryl block copolymer, an alkylol ammonium salt polymer, a block copolymer including a basic pigment affinity group, an acrylic block copolymer, a fluorinated alkyl oligomer, a polyether modified dimethylpolysiloxane copolymer, and a modified polyurethane.

The polymers used as dispersing agents are well-known to an artisan in the art and are commercially available, and thus can be used without any limitation. Examples of commercially-available dispersing agents are as follows: modified acryl block copolymers that are commercially available are DISPERBYK-2000, DISPERBYK-2001, etc.; and alkylol ammonium salt polymers are DISPERBYK- 140, DISPERBYK- 180, DISPERBYK-181, DISPERBYK- 187, BYK-151, BYK-9076, BYK-W968, BYK-W969, etc. Examples of block copolymers including a basic pigment affinity group are triblock alkyl trimethylammonium and the commercially-available copolymers of DISPERBYK-112, DISPERBYK- 116, DISPERBYK-2050, DISPERBYK-2150, BYK-9077, etc. Examples of commercially-available acrylic block copolymers are EFKA-4310, EFKA-4320, EFKA-4330, EFKA-4340, EFKA-4585, etc. Examples of fluorinated alkyl oligomers are F-471, F-474, F-475, F-477, F-478, F-479, F-486, MCF 350SF, etc. Examples of commercially-available polyether modified dimethylpolysiloxane copolymers are BKY-300, BKY-301, BKY-302, BKY-306, BKY- 307, BKY-330, BKY-331, BKY-333, BKY-335, BKY-341, BKY-344, and the like. Examples of commercially-available modified polyurethanes are EFKA-4008, EFKA- 4009, EFKA-4010, EFKA-4015, EFKA-4020, EFKA-4046, EFKA-4047, EFKA-4050, EFKA-4055, EFKA-4060, EFKA-4080, BYK-425, Dispers-710, etc.

In addition to the listed compounds that are commercially available, it is possible to use any polymer belonging to modified acryl block copolymer, alkylol ammonium salt polymer, block copolymer including basic a pigment affinity group, acrylic block copolymer, fluorinated alkyl oligomer, polyether modified dimethylpolysiloxane copolymer, and modified polyurethane without limitation.

The dispersing agent improves the dispersibility of other components (for example, the black pigment, the conductive metal, the glass powder, etc.), thereby providing a pattern and a shielding filter with excellent and uniform shielding capacity of electromagnetic interference and optical properties. In addition, the experimental results suggest that because of the specific dispersing agent contained in the paste composition, the reduced reflection of outer light and improved contrast ratio of a display device are obtained. When the pattern is formed by printing the paste composition including the dispersing agent and sintering it, the black pigment, the conductive metal, and the glass powder are efficiently dispersed in the paste composition and can be dispersed homogeneously in the printed pattern, thereby improving the optical properties.

The amount of dispersing agent is 0.05 to 1.0 parts by weight with respect to the total paste composition. When the amount is less than 0.05 parts by weight, sufficient dispersion and improved contrast ratio cannot be achieved. When the amount is higher than 1.0 part by weight, the increased electrical resistance of the pattern may deteriorate the shielding capacity of electromagnetic interference.

In another embodiment, the present invention provides a filter for shielding the electromagnetic interference manufactured by the paste composition.

A filter for shielding electromagnetic interference according to an embodiment of the present invention includes i) a glass substrate, and ii) a shielding member that is formed on the glass substrate with a mesh shape. The shielding member is configured to shield electromagnetic interference.

The shielding member may be manufactured by printing the paste composition on the glass substrate and sintering it. More preferably, the shielding member may be manufactured by printing according to the offset printing method such as gravure offset printing and sintering. The shielding member may include i) at least one first shielding portion that extends along one direction, and ii) at least one second shielding portion that crosses the first shielding portion. A width of the first shielding portion may be over 0 and is not more than 50μm, and may more preferably be in a range of 15μm to 25μm. The at least one first shielding portion may include a plurality of first shielding portions, and an average pitch of the plurality of first shielding portions may be over 0 and is not more than 500/zm. The average pitch of the plurality of first shielding portions may be in a range of 200μm to 400j«m.

An angle formed when the first shielding portion crosses the second shielding portion may be in a range of 60 degrees to 120 degrees. The angle may be in a range of 80 degrees to 100 degrees. The angle may be substantially 90 degrees.

An angle formed between the first shielding portion and an edge of the glass substrate may be in a range of 20 degrees to 70 degrees. The angle may be in a range of 35 degrees to 55 degrees. The opening may have a polygon shape. Lengths of all edges forming the polygon may be substantially the same. The polygon may be substantially a square.

The shielding member may include a conductive metal. The conductive metal may be at least one element selected from a group consisting of silver, copper, and nickel. A filter for shielding electromagnetic interference according to an embodiment of the present invention may further include an edge layer formed along an edge of the glass substrate. The shielding member may be formed on the edge layer. A filter for shielding electromagnetic interference according to an embodiment of the present invention may further include a ground member that is connected to an end of the shielding member to ground the shielding member.

A display device according to an embodiment of the present invention includes i) a glass substrate; ii) a shielding member that is formed on the glass substrate with a mesh shape; and iii) a display panel that displays an image and is opposed to the glass substrate. The shielding member is configured to shield electromagnetic interference emitted from the display panel, and is manufactured by printing the paste composition and sintering it.

The display panel may include i) first and second substrates that are opposed to each other, and ii) a black layer that is located between the first and second substrates. A direction along which the shielding member extends may cross a direction along which the black layer extends. The shielding member may contact the second substrate. A thickness of the glass substrate may be not less than a thickness of the first substrate. The shielding member may have a polygon-shaped opening. The opening may be chamfered. Lengths of all of edges forming the polygon may be substantially the same. The polygon may be substantially a square. The shielding member may be manufactured by printing the paste composition according to an offset printing method such as gravure offset printing and sintering it.

The shielding member may include i) at least one first shielding portion that extends along one direction, and ii) at least one second shielding portion that crosses the first shielding portion. A width of the first shielding portion may be over 0 and is not more than 50/im. The width of the first shielding portion may be in a range of 15jUm to

25/ffli.

The at least one first shielding portion may include a plurality of first shielding portions, and an average pitch of the plurality of first shielding portions may be over 0 and is not more than 500μm. The average pitch of the plurality of first shielding portions may be in a range of 200/M to 400μm. An angle formed when the first shielding portion crosses the second shielding portion may be in a range of 60 degrees to 120 degrees. The angle may be in a range of 80 degrees to 100 degrees. The angle may be substantially 90 degrees.

An angle formed between the first shielding portion and an edge of the glass substrate may be in a range of 20 degrees to 70 degrees. The angle may be in a range of 35 degrees to 55 degrees.

The display panel may be a plasma display panel.

The filter for shielding electromagnetic interference and a display device of the present invention will be explained in detail below with reference to the attached drawings in order for those skilled in the art in a field of the present invention to easily perform the present invention. However, the present invention can be realized in various forms and is not limited to the embodiments explained below. In addition, like reference numerals refer to like elements in the present specification and drawings.

All terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present invention.

FIG. 1 schematically shows a filter 100 for shielding electromagnetic interference according to an embodiment of the present invention. An enlarged circle of FIG. 1 shows a magnified inner portion of the filter 100 for shielding electromagnetic interference.

As shown in FIG. 1, the filter 100 for shielding electromagnetic interference includes a glass substrate 20, a shielding member 10, an edge layer 30, and a ground member 40. The glass substrate 20 is used for forming the shielding member 10 by using an offset printing method such as gravure offset printing method. A long edge of the glass substrate 20 is parallel to an x-axis, while a short edge thereof is parallel to a y-axis.

The shielding member 10 is grounded by being connected to the ground member 40. Therefore, the shielding member 10 can absorb and remove electromagnetic interference. As a result, the shielding member 10 functions as a filter for shielding the electromagnetic interference. The edge layer 30 is formed along an edge of the glass substrate 20, and the ground member 40 is located at both ends of the glass substrate 20 along an x-axis direction in order to ground the shielding member 10. As shown in an enlarged circle of FIG. 1, the shielding member 10 is formed with a mesh shape. The filter 100 for shielding electromagnetic interference is mainly used in a display device. Therefore, the shielding member 10 is formed with a mesh shape in order to display an image projected from the display device to the outside. Since the shielding member 10 has an opening 109, the image can be seen through the opening 109 while the electromagnetic interference is blocked.

The shielding member 10 includes first and second shielding portions 101 and 103. The first shielding portion 101 extends along an x-axis direction to cross the second shielding portion 103. That is, as shown in the enlarged circle of FIG. 1, the first and second shielding portions 101 and 103 form an angle αl while meeting each other. The angle αl may be in a range of 60 degrees to 120 degrees. If the angle αl is too large or too small, a distance between the first and second shielding portions 101 and 103 becomes too small, and thereby an opening ratio may become too small. More preferably, the angle αl may be in a range of 80 degrees to 100 degrees. In this case, a distance between the first and second shielding portions 101 and 103 can be suitably maintained. In addition, most preferably, the angle may be substantially 90 degrees.

The method for manufacturing a filter for shielding electromagnetic interference includes the steps of i) providing a gravure roll in which a mesh-shaped groove is formed; ii) filling the groove with a conductive paste; iii) providing a blanket roll that is opposed to the gravure roll and rotates in a direction that is opposite to a rotating direction of the gravure roll; iv) transferring the conductive paste to the blanket roll while rotating the gravure roll; v) providing a glass substrate; vi) printing the conductive paste on the glass substrate while the blanket roll moves on the glass substrate; and vii) forming a shielding member of a single layer that shields electromagnetic interference on the glass substrate by plasticizing the conductive paste.

In the embodiment of the present invention, a gravure roll 55 (shown in FIG. 3) in which grooves 551 (shown in FIG. 3) with a mesh shape are formed along oblique line directions is used for forming the shielding member 10 with a mesh shape. If the grooves 551 are not formed along oblique line directions but are perpendicular to a rotating direction of the gravure roll 55, a paste composition 10a (shown in FIG. 3) as a resource of the shielding member 10 received in the groove 551 is not removed well from the groove 551. That is, since the paste composition 10a is not influenced by a rotating force of the gravure roll 55, it is not easy to remove the paste composition 10a from the gravure roll 55. On the contrary, when a rotating direction of the gravure roll 55 corresponds to a direction along which the groove 551 extends, the paste composition 10a can be removed well from the groove 551 by a rotating force of the gravure roll 55. Therefore, when the groove 551 is formed to correspond to the rotating direction of the gravure roll 55, the shielding member 10 with an opening 109 having a uniform size can be formed.

More specifically, when the groove is only formed to correspond to the rotating direction of the gravure roll, it is impossible to form a shielding member with a mesh. That is, when the mesh shape is a rectangle shape, it is difficult to transfer the paste composition to a blanket roll since another groove should also be formed along a direction to be perpendicular to the rotating direction of the gravure roll. As shown in the enlarged circle of FIG. 1, when the shielding member 10 is formed on the glass substrate 20 using the above-described method, the first shielding portion 101 forms a certain angle α2 with the x-axis direction. Here, the angle α2 may be in a range of 20 degrees to 70 degrees. If the angle α2 is too small or too large, the first and second shielding portions 101 and 103 are dense, and thereby an effect of shielding electromagnetic interference can be deteriorated. In addition, when the filter 100 for shielding electromagnetic interference is used in the display device 200 (shown in FIG. 4), it is overlapped with a black layer 651 of the display device 200, and thereby a moire phenomenon can occur. More specifically, the angle α2 may be in a range of 35 degrees to 55 degrees.

As shown in the enlarged circle of FIG. 1, resolution of the image can be enhanced by maximizing the area of the opening 109 while forming a width W of the shielding member 10 to be smaller. For this, the width W of the shielding member 10 may be over 0 and may not be more than 50//m. In this case, the shielding member 10 cannot be recognized with the naked eye. When the width W of the shielding member 10 is too large, the resolution of the image is deteriorated as the size of the opening 109 becomes small. More specifically, the width W of the shielding member 10 is preferably in a range of 15μm to 25 μm.

Meanwhile, an average pitch P of the shielding member 10 may be over 0 and not more than 500μm. When the average pitch P of the shielding member 10 is too large, the electromagnetic interference can be discharged to the outside without being absorbed since the shielding member 10 is not densely formed. As a result, an effect of shielding electromagnetic interference is deteriorated. More specifically, it is preferable that the average pitch P of the shielding member 10 may be in a range of

The shielding member 10 can include a conductive metal to maximize an effect of shielding electromagnetic interference. The conductive metal has a good effect of shielding electromagnetic interference since it can collect the electromagnetic interference passing through the filter 100 for shielding electromagnetic interference. Silver, copper, nickel, or alloys thereof can be used as the conductive metal. Since the conductive metal has good electrical conductivity, it can effectively shield the electromagnetic interference.

FIG. 2 partially shows a cross-sectional structure of the filter 100 for shielding electromagnetic interference, cutting along a line II-II of FIG. 1. As shown in FIG. 2, the shielding member 10 is formed on an edge layer 30 formed on the glass substrate 20. Since the edge layer 30 contains black ceramics, it can improve appearance of the filter 100 for shielding electromagnetic interference. In addition, the edge layer 30 can effectively connect the ground member 40 to the shielding member 10. A thickness of the edge layer 30 may be in a range of about 15μm to about 20μm. After the shielding member 10 is formed on the edge layer 30 formed on the glass substrate 20 by printing a paste composition using the offset printing method, the ground member 40 is formed thereon. A conductive film tape can be used as the ground member 40.

FIG. 3 schematically shows a manufacturing process of the filter 100 for shielding electromagnetic interference of FIG. 1. The filter 100 for shielding electromagnetic interference can be manufactured by using an offset printing device 500. The offset printing method will be explained in detail below.

As shown in FIG. 3, the offset printing device 500 includes a dispenser 51, a doctor blade 53, a gravure roll 55, and a blanket roll 57. In the offset printing method, the offset printing device 500 is used. The offset printing method includes an off process and a set process. In the off process, the paste composition 10a is removed from the gravure roll 55. The removed paste composition 10a is coated on the glass substrate 20 in the set process. The dispenser 51 discharges the paste composition 10a at a predetermined time intervals. The paste composition 10a discharged from the dispenser 51 is received in the grooves 551 formed in the gravure roll 55. The paste composition 10a may contain elastic organic materials, conductive metals, a flux, a binder, etc., as explained above. A solvent having a boiling point of 200 ^°C or higher and a solvent having a boiling point lower than 200 "C may be used in combination and a glass powder such as a glass frit may be used as a binder. The organic material may include an acrylate resin, an acryl resin, a polyester, a polyurethane, an oligomer, etc. The solvent and the organic materials are removed in a process of sintering the glass substrate 20. The paste composition 10a may further include a black pigment and a dispersing agent.

Since an amount of the paste composition 10a received in the groove 551 is large, the paste composition 10a may overflow outside of the groove 551. Therefore, overflowed paste composition 10a is removed by the doctor blade 53 while the gravure roll 55 rotates along a direction indicated by an arrow (counter-clockwise direction). Since the doctor blade 53 contacts an outer surface of the gravure roll 55, the paste composition having overflowed to the outside of the groove 551 can be effectively removed. Therefore, the groove 551 of the gravure roll 55 can be suitably filled with the paste composition 10a without overflowing it.

The blanket roll 57 is located to oppose the gravure roll 55. The blanket roll 57 rotates in a direction (clockwise direction) that is opposite to a rotating direction of the gravure roll 55. As a result, the paste composition 10a received in the grooves 551 is transferred to the blanket roll 57 while the gravure roll 55 meets the blanket roll 57. Therefore, the paste composition 10a is attached to an outer surface of the blanket roll 57.

The blanket roll 57 coats the paste composition 10a on the glass substrate 20 while moving on the glass substrate 20 along a direction indicated by an arrow. The glass substrate 20 is prepared by being washed. The paste composition 10a with a mesh shape is formed on the glass substrate 20 in order to form the shielding member 10 (shown in FIG. 1).

Next, solvents and/or organic materials contained in the paste composition 10a are removed by loading the glass substrate 20 into a heating furnace (not shown) to heat it. The paste composition 10a may be dried before a sintering process. The shielding member can be directly formed by heating the glass substrate 20 and removing the organic materials and the solvent. That is, the filter for shielding electromagnetic interference is directly manufactured without performing other processes such as etching of the paste composition 10a. Therefore, the process is simple, and thereby manufacturing cost of the filter for shielding electromagnetic interference can be reduced.

The offset printing method used in manufacturing of the filter for shielding electromagnetic interference includes a sintering process, and thus, a glass substrate 20 is used rather than a resin substrate which is weak to heat. Therefore, a glass substrate 20 is used instead of a resin substrate. Since other contents of the offset printing method can be understood by those skilled in the arts in the technical field of the present invention, detailed description thereof is omitted.

A copper film is firstly attached to a resin film when the filter for shielding electromagnetic interference is manufactured by using a photolithography method instead of an offset printing method. Then, a dry film resist is laminated on the copper film and an exposing process, a developing process, an etching process, and an exfoliation process are performed to form a pattern. Therefore, the manufacturing process is complicated, and thereby productivity is not good.

In addition, when the filter for shielding electromagnetic interference is manufactured by using a plating method, desired electrical conductivity should be obtained by forming a pattern on a resin film and plating copper thereon. However, wasted liquid from the plating process causes environmental pollution.

A pattern cannot be directly formed on the glass substrate in the above- described photography method or the plating method. For example, a mother substrate is wound in a form of a roll and is then submerged in a plating bath in the plating method. However, the glass substrate cannot be wound in a form of a roll, and thereby it is impossible to plate the glass substrate to form a shielding member. In addition, when the glass substrate is used, the process is complicated because the pattern should be attached to the glass substrate. The offset printing method can solve the above problems. That is, since the shielding member 10 of a single layer is directly formed on the glass substrate 20, the process is simplified and so manufacturing cost is reduced. Meanwhile, harmful materials are not discharged in the offset printing method, and thereby environmental pollution is not caused.

FIG. 4 schematically shows a display device 200 provided with the filter 100 for shielding electromagnetic interference of FIG. 1. An enlarged circle of FIG. 4 shows a magnified display device 200 to be seen from a z-axis direction.

As shown in FIG. 4, the filter 100 for shielding electromagnetic interference is fixed on a display panel 600 (shown in FIG. 5) using a supporting member 110. Therefore, the filter 100 for shielding electromagnetic interference can be stably received in the display device 200.

As illustrated in the enlarged circle of FIG. 4, the shielding member 10 is located on a black layer 651 included in the display panel 600 (shown in FIG. 5). In addition, the black layer 651 is positioned between the first substrate 610 and the second substrate 620 of the display panel. Although not shown in the enlarged circle of FIG. 4, the second substrate 620 (shown in FIG.5) is located between the shielding member 10 and the black layer 651, and a glass substrate 20 (shown in FIG. 5)is on the shielding member 10.

The shielding member 10 shields electromagnetic interference emitted from the display panel 600. As shown in the enlarged circle of FIG. 4, the shielding member 10 has an opening 109 with a lozenge shape. Although not shown in FIG. 4, the shielding member 10 preferably has a square shape. In this case, the shape of the shielding member 10 is optimized, and thereby the effect of shielding electromagnetic interference can be maximized. Lengths of the four edges forming the opening 109 are substantially the same.

Since lengths of the four edges are substantially the same, the shape of the shielding member 10 is regular. As a result, intensity of light emitted from the opening 109 is uniform, and thereby a uniform image can be displayed. Meanwhile, although the opening 109 is shown to have a lozenge shape in the enlarged circle of FIG. 4, this is merely to illustrate the present invention and the present invention is not limited thereto. Therefore, the opening 109 may have a polygonal shape.

The shielding members 10 are formed with the shielding portions crossing each other by the offset printing method. Therefore, the width of the shielding members 10 becomes a little larger at a crossing point where the shielding members 10 meet each other. As a result, the opening 109 has a chamfered shape. That is, since the width of the shielding members 10 becomes a little larger at a crossing point of the shielding members 10, the opening 109 has a shape in which corners are removed. The shielding member 10 is continuously formed without being cut due to the above- described shape of the opening 109, and thereby electromagnetic interference can be shielded by an entire surface of the shielding member 10.

As shown in the enlarged circle of FIG. 4, the shielding members 10 are formed in such a way that a direction along which shielding members 10 extend crosses a direction in which the black layer 651 extends. Therefore, it is possible to prevent a phenomenon in which an image becomes blurred. Furthermore, since the shielding member 10 has a fine width that cannot be recognized with the naked eye, there is almost no influence on the quality of the image. Therefore, as shown in the enlarged circle of FIG. 4, an image with high resolution can be displayed even if the shielding member 10 is located on the black layer 651.

FIG. 5 partially shows a cross-sectional cut along a line V-V of FIG. 4. FIG. 5 shows a plasma display panel as a display panel 600. The plasma display panel shown in FIG. 5 is merely to illustrate the present invention and the present invention is not limited thereto. Therefore, the filter for shielding electromagnetic interference can be used in another display panel.

The display panel 600 includes first and second substrates 610 and 620, display electrodes 680, address electrodes 640, sidewalls 660, a phosphor layer 670, a dielectric layer 630, a protective layer 635, and a black layer 651. An internal space of the display panel 600 is filled with a discharge gas. The first and second substrates 610 and 620 are opposed to each other. The sidewalls 660 form a plurality of discharge cells and a phosphor layer is formed in the discharge cells. The dielectric layer 630 protects the address electrodes 640 and the display electrodes 680 from electrons. The protective layer 635 protects the dielectric layer 630 located thereon.

When a voltage is applied to the address electrodes 640 and the display electrodes 680, a discharge occurs between the address electrodes 640 and the display electrodes 680. Ultraviolet rays generated by the discharge collide with the phosphor layer 670 and then visible rays are emitted therefrom. Meanwhile, the black layer 651 is formed on the sidewalls 660 to improve the contrast ratio. The black layer 651 is located between the first and second substrates 610 and 620. Since the black layer 651 is located on the sidewall 660 that does not emit light, it can reduce a loss of light emitted from the phosphor layer 670. More specifically, the black layer 651 is formed while contacting the upper side of the sidewalls 660 as shown in FIG.5, or may be formed on the dielectric layer 630 on the sidewalls 600.

As shown in FIG. 5, the filter 100 for shielding electromagnetic interference is located on the display panel 600. Therefore, the filter 100 for shielding electromagnetic interference can shield electromagnetic interference emitted from the display panel 600. Since the shielding member 10 contacts the second substrate 620, it is not exposed to the outside. Therefore, the shielding member 10 can be prevented from being harmed and the appearance is prevented from being deteriorated due to the shielding member 10.

Meanwhile, if respective thicknesses of the first and second substrates 610 and 620 are small, the display panel 600 is weak against an external shock. Therefore, strength of the display device 200 is reinforced by using the filter 100 for shielding electromagnetic interference including the glass substrate 20. That is, since the thickness of the filter 100 for shielding electromagnetic interference is included in the thickness of the display device 200 so that the display device 200 becomes thick, it is strong against an external shock. For example, the thickness 2Ot of the glass substrate 20 is formed to be greater than the thickness 620 of the second substrate 620, and thereby durability of the display device 200 can be improved by the filter 100 for shielding electromagnetic interference.

As disclosed above, the black conductive paste composition of the present invention includes a specific dispersing agent and thus provides a shielding filter with uniform shielding capacity and optical properties. In addition, the shielding filter can be applied to a display device, and can reduce the reflection of outer light and improve the contrast.

In addition, because the black conductive paste composition includes the black pigment and the glass powder, the composition can be directly printed on the glass substrate according to a gravure offset printing method, and the organic materials can be removed in the sintering process.

As described above, a filter for shielding electromagnetic interference can be manufactured by using an offset printing method that has a simpler manufacturing process than other processes, and a low cost.

In addition, an effect for shielding electromagnetic interference of the display device can be maximized when the display device provided with the above-described filter for shielding electromagnetic interference is manufactured.

The present invention will be explained in detail with reference to the exemplary examples below. The exemplary examples are merely to illustrate the present invention and the present invention is not limited thereto.

Examples 1-5 and Comparative Example 1

According to the components and amounts as shown in Table 1, a solvent, a glass powder, a conductive metal, a black pigment, and a dispersing agent were added to an acrylate resin while agitating at room temperature, and finally with a 3 -roll mill to produce a desired black conductive paste composition for gravure offset printing. [Table 1]

In Table 1, the modified acrylic block copolymer is DISPERB YK-2001 (BYK), the alkylol ammonium salt polymer is DISPERBYK- 180(BYK), the block copolymer including a basic pigment affinity group is DISPERB YK-2050(B YK), the acrylic block copolymer is EFKA-4340(EFKA), and the fluorinated alkyl oligomer is F-

477(DAINIPPON INK AND CHEMICALS, INC.). The weight average molecular weight of the acrylate resin was 25,000, where a ratio of weight of methyl acrylate

(MA), butyl methacrylate (BM), hydroxyethyl methacrylate (HEMA), and methyl methacrylate (MMA) was 30:40:10:20. The BCA is butylcarbitol acetate and the MEDG is diethyleneglycolmethylethylether. The glass powder was a Bi-based glass powder

The conductive metal was a silver powder with an average particle size of 1.5μm. The black pigment was Co.

Examples 6-8 and Comparative Example 2

A black conductive paste composition was manufactured according to substantially the same method of Example 1, except that the particle size of silver powder was different, as shown in Table 2. [Table 2]

Experimental Example

(Formation of the filter for shielding electromagnetic interference)

The paste compositions of Examples 1 to 8 and Comparative Examples 1 to 2 were printed to obtain a pattern with a proper shape and size by using a gravure offset printing method.

That is, the paste compositions were formed on the glass substrate in a mesh- shaped pattern by using an offset printing device that is the same as that shown in FIG. 3. The line width of the mesh-shaped pattern was 25μm and the pitch thereof was 250μm. Next, the paste composition formed on the glass substrate was maintained at 500 to 540 ^°C for 20 minutes in a sintering process to produce a mesh-shaped pattern used for a shielding filter.

(Measurement of property of shielding electromagnetic interference) To measure the properties of reflecting outer light and the contrast, optical properties of the filters for shielding electromagnetic interference that were manufactured by using the paste compositions of Examples lto 5 and Comparative Example 1 were estimated.

The opposite side of the filters was irradiated with D65 light. The optical properties of the filters that were manufactured by using the paste compositions of Examples lto 5 and Comparative Example 1 were measured and evaluated. The measuring took place at 6 points which were averaged. The estimations are shown in Table 3 below. [Table 3]

As shown in Table 3, the shielding filter made of the paste composition for a dispersing agent described in Examples 1 to 5 showed a lower total reflectance value and diffusion reflectance value than that of Comparative Example 1.

The shielding filters obtained in Examples 1 to 5 were used in display devices such as PDPs reduced the reflectance of outer light more efficiently, and thereby improved the contrast ratio of the display devices.

(Evaluation of printing properties of shielding filter) The dispersing and printing properties (printability and straightness of pattern) of the filters for shielding electromagnetic interference that were manufactured by using the paste compositions of Examples 6 to 8 and Comparative Example 2 were estimated on the basis of the following points of reference, and are shown in Table 4. Microphotographs of mesh-shaped patterns obtained by the compositions of Examples 6 to 7 and Comparative Example 2 were taken and are shown in FIGs. 6 to 8.

1) Reference for evaluating the dispersion:

O: i) no layer separation of the inorganic material and organic material, ii) no gellation, and iii) no larger particles lumped than each particle used in the components for the paste composition.

Gellation: occurrence of gellation

X: occurrence of at least one of i), ii) and iii)

2) Reference for evaluating printability:

O: i) non-uniformity of transcribing a pattern, ii) no occurrence of hole in pattern, and iii) no occurrence of pattern break;

X: occurrence of at least one of i), ii), and iii)

3) Reference for evaluating the straightness of pattern: O: formation of smooth straight line in pattern picture X: not being a smooth straight line in pattern picture

[Table 4]

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A black conductive paste composition comprising a) an acrylate resin, b) a solvent, c) a glass powder, d) a conductive metal, e) a black pigment, and f) a dispersing agent that is at least one selected from the group consisting of a modified acrylic block copolymer, an alkylol ammonium salt polymer, a block copolymer including a basic pigment affinity group, an acrylic block copolymer, a fluorinated alkyl oligomer, a polyether modified dimethylsiloxane copolymer, and a modified polyurethane.

2. The black conductive paste composition of Claim 1, wherein the composition is used for preparing a filter for shielding electromagnetic interference.

3. The black conductive paste composition of Claim 1, wherein the composition is printed on a glass substrate according to an offset printing method and sintered to produce a filter for shielding electromagnetic interference.

4. The black conductive paste composition of Claim 1, wherein the composition comprises a) 5 to 15 parts by weight of an acrylate resin, b) 5 to 15 parts by weight of a solvent, c) 1 to 10 parts by weight of a glass powder, d) 50 to 90 parts by weight of a conductive metal, e) 1 to 10 parts by weight of a black pigment, and f) 0.05 to 1.0 parts by weight of a dispersing agent.

5. The black conductive paste composition of Claim 1, wherein the black pigment comprises a cobalt-based compound, a copper-based compound, a ruthenium-based compound, a manganese-based compound, a nickel-based compound, a chromium- based compound, or a steel-based compound.

6. The black conductive paste composition of Claim 1, wherein the black pigment comprises a cobalt-based compound.

7. The black conductive paste composition of Claim 6, wherein the black pigment further comprises an auxiliary pigment of a copper-based compound, a ruthenium-based compound, a manganese-based compound, a nickel-based compound, a chromium- based compound, or a steel-based compound.

8. The black conductive paste composition of Claim 1, wherein the acrylate resin has a weight average molecular weight of 5,000 to 100,000.

9. The black conductive paste composition of Claim 1, wherein the solvent comprises at least one of a high boiling point solvent having a boiling point of 200 ^°C or higher, and at least one of a low boiling point solvent having a boiling point that is lower than 200 ^°C .

10. The black conductive paste composition of Claim 9, wherein the high boiling point solvent is at least one selected from the group consisting of gammabutyrolactone, butylcarbitolacetate, carbitol, methoxymethyletherpropionate, and terpineol.

11. The black conductive paste composition of Claim 9, wherein the low boiling point solvent is at least one selected from the group consisting of propyleneglycol monomethylether, diethyleneglycol methylethylether, diethyleneglycol monomethylether, dipropyleneglycol monomethylether, propyleneglycol monomethyletherpropionate, ethyletherpropionate, propyleneglycol monomethyletheracetate, methylethylketone, and ethyllactate.

12. The black conductive paste composition of Claim 9, wherein the solvent comprises 12 to 88 wt% of the high boiling point solvent and 12 to 88 wt% of the low boiling point solvent.

13. The black conductive paste composition of Claim 1, wherein the glass powder is a Pb-based glass powder, a Pb-free glass powder, a colored glass powder obtained by adding a black or colored pigment, or a glass powder including a color component of V₂O₅.

14. The black conductive paste composition of Claim 1, wherein the conductive metal is at least a metal powder for an electrode selected from the group consisting of silver, copper, nickel, and alloys thereof.

15. The black conductive paste composition of Claim 14, wherein the metal powder has an average particle diameter of 0.3~30μm.

16. A filter for shielding electromagnetic interference, the filter comprising: a glass substrate; and a shielding member formed on the glass substrate in a mesh shape to shield electromagnetic interference, wherein the shielding member is manufactured by printing the paste composition of any one of Claims 1 to 15 on the glass substrate and sintering it.

17. The filter of Claim 16, wherein the shielding member is manufactured by using an offset printing method and a sintering method.

18. The filter of Claim 16, wherein the shielding member comprises: at least one first shielding portion that extends along one direction; and at least one second shielding portion that crosses the first shielding portion.

19. The filter of Claim 18, wherein a width of the first shielding portion is over 0 and is not more than 50μm.

20. The filter of Claim 18, wherein the at least one first shielding portion comprises a plurality of first shielding portions, wherein an average pitch of the plurality of first shielding portions is over 0 and is not more than 500μm.

21. The filter of Claim 18, wherein an angle formed when the first shielding portion crosses the second shielding portion is in a range of 60 degrees to 120 degrees.

22. The filter of Claim 21, wherein the angle is substantially 90 degrees.

23. The filter of Claim 18, wherein an angle formed between the first shielding portion and an edge of the glass substrate is in a range of 20 degrees to 70 degrees.

24. The filter of Claim 1, wherein the shielding member has an opening with a polygonal shape and the opening is chamfered.

25. The filter of Claim 24, wherein lengths of all of edges forming the polygon are substantially the same.

26. The filter of Claim 25, wherein the polygon is substantially a square.

27. The filter of Claim 16, further comprising an edge layer formed along an edge of the glass substrate and wherein the shielding member is formed on the edge layer.

28. The filter of Claim 27, further comprising a ground member that is connected to an end of the shielding member to ground the shielding member.

29. A display device comprising: a glass substrate; a shielding member formed on the glass substrate in a mesh shape to shield electromagnetic interference; and a display panel that displays an image and is opposed to the glass substrate, wherein the shielding member is manufactured by printing the paste composition of any one of Claims 1 to 15 on the glass substrate and sintering it.

30. The device of Claim 29, wherein the display panel comprises: first and second substrates that are opposed to each other; and a black layer that is located between the first and second substrates, wherein a direction along which the shielding member extends crosses a direction along which the black layer extends.

31. The device of Claim 29, wherein the shielding member contacts the second substrate.

32. The device of Claim 29, wherein the shielding member is manufactured by using an offset printing method and a sintering method.

33. The device of Claim 29, wherein the shielding member comprises: at least one first shielding portion that extends along one direction; and at least one second shielding portion that crosses the first shielding portion.

34. The device of Claim 33, wherein a width of the first shielding portion is over 0 and is not more than 50μm.

35. The device of Claim 33, wherein the at least one first shielding portion comprises a plurality of first shielding portions, wherein an average pitch of the plurality of first shielding portions is over 0 and is not more than 500μm.

36. The device of Claim 33, wherein an angle formed when the first shielding portion crosses the second shielding portion is in a range of 60 degrees to 120 degrees.

37. The device of Claim 36, wherein the angle is substantially 90 degrees.

38. The device of Claim 33, wherein an angle formed between the first shielding portion and an edge of the glass substrate is in a range of 20 degrees to 70 degrees.

9. The device of Claim 33, wherein the display device is a plasma display panel.