KR20100104288A - Composition for fabricating black layer of pdp electrode - Google Patents

Abstract

PURPOSE: A composition for forming a black layer of a PDP electrode is provided to improve a contrast ratio of a panel by forming a black layer on the lower side of a bus electrode. CONSTITUTION: A transparent electrode(110) is formed on a front substrate(100). A bus electrode(112) is formed on the transparent electrode. A first dielectric layer(114) and a MgO layer(118) protecting the first dielectric layer are formed on the transparent layer. A black layer(111) is formed on the lower side of the bus electrode. A second dielectric layer(115) is formed on a rear substrate(150). A partition(120) including a fluorescent material(132) is formed on the second dielectric layer.

Description

Composition for formation of black layer of PD electrode {COMPOSITION FOR FABRICATING BLACK LAYER OF PDP ELECTRODE}

The present invention relates to a composition for forming a black layer of a plasma display panel (PDP) electrode, and more particularly to a composition for forming a black layer of a PDP electrode having excellent sedimentation stability and dispersion characteristics on a low viscosity. will be.

Plasma display panels (PDPs) are one of the flat panel display devices. In recent years, the demand for plasma display panels (PDPs) is rapidly increasing, competing with liquid crystal displays (LCDs) and projection TVs (Projection TVs).

Taking the AC type PDP as an example, the structure of the PDP is a back substrate having a cell structure usually composed of a glass substrate called a front substrate, in which a transparent electrode (holding electrode) and a bus electrode are covered with a dielectric layer, and an address electrode, a dielectric layer, a partition wall, and a phosphor. It includes a glass substrate, and has a form disposed facing each other so that the electrodes on both sides orthogonal.

Light emission is performed by applying a voltage between the electrodes on both sides, generating a discharge phenomenon in the cell, and exciting the phosphor in the cell by the generated ultraviolet rays. The image obtained by the combination of each of the red cyan light emitting (RGB) cells that are emitted by the structure of the panel is recognized behind the surface on which the electrode of the front substrate is formed. For this reason, a method of forming a black electrode between the transparent electrode and the bus electrode has been known as a method of suppressing recognition from the back of the bus electrode on the front substrate corresponding to the display surface in order to improve the quality of the displayed image. .

The black layer included in the PDP electrode needs to undergo a firing process of 500 to 600 ° C. during the manufacturing process, and in a composition having an organic black pigment and expressing black like the black layer for LCD, the black layer can be maintained. Inorganic black pigments with excellent thermal stability are used. In addition, an inorganic material such as glass frit is required for adhesion to the substrate.

In order to form an electrode, a method of forming a pattern by printing and drying a black layer using a screen printing method and then screen printing and drying a silver (Ag) paste, which is a conductive layer in succession, and then exposing and developing is used. . However, in the case of using such a screen printing method, not only the loss of material is very large, but there is a problem in that the printing thickness is changed due to the change of the tension of the printing screen.

In order to compensate for this disadvantage, the composition constituting the black layer is coated using a slit coater, dried, exposed, and developed to form a patterned black layer, and then offset printing on the black layer (Off- A method has been proposed in which a conductive layer is printed by a Set Print method and then fired to form a PDP electrode.

When the composition is applied using the slit coater to form a black layer, the viscosity of the composition requires a very low viscosity of 200 cps or less. However, due to the high specific gravity of the black pigment and the organic binder included in the composition, it is difficult to obtain a good coating film using a slit coater because the composition is separated, aggregated, and settled during storage of the composition.

The composition for forming a black layer conventionally used includes black pigments and glass frits having a mean particle size (D50) of about 1.2 μm, a D90 of about 4.5 μm, and a maximum particle size (Dmax) of about 10 μm. . Therefore, the particle size distribution of black pigment and glass frit is very wide. For this reason, in the conventional composition for forming a black layer, large particles settle within a few hours during slit coating, and aggregation occurs. Therefore, the uniformity of the applied black layer is lowered, and problems such as clogging of the tube occur in the black layer forming step.

In addition, when a paste having a viscosity of 1,000 cps or more prepared by screen printing to form a black layer is applied to the slit coating, a flat surface cannot be obtained and a thin film cannot be formed.

One object of the present invention is to provide a composition for forming a black layer of a PDP electrode excellent in sedimentation stability and dispersion characteristics at low viscosity and capable of slit coating.

Another object of the present invention is to provide a PDP electrode using the composition.

The composition for forming a black layer of a PDP electrode according to the present invention for achieving the above object is a black pigment having an average particle diameter of 300 ~ 500nm, a glass frit having an average particle diameter of 150 ~ 250nm, an organic binder, a photopolymerizable compound, a photopolymerization initiator And a solvent.

At this time, the black pigment has a maximum particle size of 0.6 ~ 2㎛, the glass frit is preferably a maximum particle size of 0.4 ~ 1.5㎛, the composition has a viscosity in the range of 10 ~ 200cps.

Preferably, the composition for forming a black layer of the PDP electrode may be 3 to 15% by weight of black pigment, 1 to 20% by weight of glass frit, 5 to 40% by weight of organic binder, 1 to 20% by weight of photopolymerizable compound, and photopolymerization initiator 0.1. It comprises a solvent as -10 weight% and remainder.

According to another aspect of the present invention, there is provided a PDP electrode comprising: (a) applying the above-described composition to a substrate by a slit coating method; (b) drying the applied composition to form a composition film; And (c) patterning the composition film using a photolithography process.

The composition for forming a black layer of the PDP electrode according to the present invention includes nano-grade black pigment and glass frit in the composition to suppress aggregation and sedimentation, and may also have a low viscosity of 200 cps or less, so that the slit coating method may be used. There are advantages to it.

Accordingly, the black layer formed by using the composition for forming a black layer according to the present invention has an excellent effect on sedimentation stability, aggregation and surface roughness characteristics.

Hereinafter, the composition for forming a black layer of the PDP electrode according to the present invention will be described in detail with reference to the accompanying drawings.

Black layer formation composition

The composition for forming a black layer of a PDP electrode according to the present invention comprises a black pigment, a glass frit, an organic binder, a photopolymerizable compound, a photopolymerization initiator and a solvent. At this time, the black pigment has an average particle diameter of 300 ~ 500nm, the glass frit has an average particle diameter of 150 ~ 250nm.

Black Pigment

As the black pigment used in the present invention, a black pigment having a very high resistivity as a conductor, such as an oxide of a transition metal, a boride of a transition metal, a nitride of a transition metal, and a carbide of a transition metal, may be used. Such black pigments may be, for example, cobalt oxides, chromium-copper oxides, chromium-nickel-manganese oxides or mixtures thereof.

The average particle diameter of the black pigment used in the present invention is 300 ~ 500nm. If the average particle diameter of the black pigment is less than 300 nm, reagglomeration may occur, and dispersion may be difficult in the organic binder. If the average particle diameter exceeds 500 nm, it causes rapid sedimentation and aggregation. The black pigment having an average particle diameter of 300 to 500 nm can be obtained by reducing the particle diameter through the wet grinding method and classifying.

On the other hand, it is preferable that the maximum particle diameter of a black pigment is 0.6-2 micrometers, More preferably, it is 0.8-1.5 micrometers. When the maximum particle diameter of the black pigment is in the above range may have excellent dispersion stability.

The content of the black pigment is preferably included in the content ratio of 3 to 15% by weight of the total composition. When the black pigment is included in less than 3% by weight, the electrode pattern formed may not exhibit a sufficient degree of blackness, and when it exceeds 15% by weight, the light transmittance may be lowered and the pattern resolution may be lowered.

Glass frit

The glass frit used in the present invention has a softening point of 300 to 600 ° C., and may be one containing lead oxide, bismuth oxide, zinc oxide, or the like as a main component, and a glass transition temperature of 200 to 500 ° C. is more preferable. If the glass transition temperature of the glass frit is less than 200 ° C., softening at the time of firing the pattern to be formed progresses, making it difficult to maintain the shape of the firing pattern, and bubbles are also easily generated. Moreover, when the glass transition temperature of glass frit exceeds 500 degreeC, adhesiveness after baking is hard to be obtained.

The glass frit used in the present invention has an average particle diameter of 150 to 250 nm. If the average particle diameter of the glass frit is less than 150 nm, reagglomeration may occur and dispersion may be difficult in the organic binder. If the average particle diameter exceeds 250 nm, it causes rapid sedimentation and aggregation. The glass frit having an average particle diameter of 150 to 250 nm may be obtained by a wet sol-gel method, a flame spray pyrolysis method, or the like.

On the other hand, it is preferable that the largest particle diameter of a glass frit is 0.4-1.5 micrometers, More preferably, it is 0.6-1.2 micrometers. If the maximum particle diameter of the glass frit is in the above range may have excellent dispersion stability.

The content of the glass frit is preferably 1 to 20% by weight, more preferably 3 to 15% by weight of the total composition. When the glass frit is included in an amount of less than 1% by weight, the adhesion between the electrode pattern and the electrode substrate after firing is not easy, and when the glass frit is more than 20% by weight, the content of the conductive material or the organic binder is relatively low. Conductivity and mechanical strength may be lowered.

Organic Binder

The organic binder used in the present invention may be selected to be soluble in a development liquid used in a photolithography process for patterning a black layer after coating the composition of the present invention on a substrate. For example, an aqueous alkali solution (for example, a 0.4wt% Na ₂ CO ₃ aqueous solution for example) used as a developing solution, it is possible to use a carboxyl group-containing resin as the organic binder. At this time, both the carboxyl group-containing resin which has an ethylenically unsaturated double bond, and the carboxyl group-containing resin which does not have an ethylenically unsaturated double bond can be used for carboxyl group-containing resin.

Examples of the material that can be used as the organic binder include carboxyl group-containing monomers such as acrylic acid monomers, methacrylic acid monomers and itaconic acid monomers, and acrylic acid esters (methyl acrylate, ethyl methacrylate, etc.), styrene monomers and acrylamide monomers. And copolymers of monomers having ethylenically unsaturated double bonds such as acrylonitrile monomers, cellulose, water-soluble cellulose derivatives, and the like, and these materials may be used alone or in combination.

On the other hand, the weight average molecular weight of the organic binder is about 1,000 to 300,000, preferably in the range of 5,000 to 100,000, the acid value is preferably 20 to 250mgKOH / g.

If the average molecular weight and the acid value is out of the above range, over-development or non-development occurs during development, and it may be difficult to implement the desired patterning.

The organic binder is preferably included in the content ratio of 5 to 40% by weight of the total composition, more preferably 10 to 30% by weight. When the organic binder is included in less than 5% by weight, there may be a problem that the sedimentation of the inorganic particles is faster due to insufficient binder content, and if the organic binder exceeds 40% by weight, the film density after the firing may be reduced. Can be.

Photopolymerizable compound

As the photopolymerizable compound which can be used in the present invention, a polymerizable compound having an ethylenically unsaturated bond used in a conventional photosensitive composition can be used, for example, oleethylene glycol diacrylate, polyurethane diacrylate, trimes Tyrol propane triacrylate, pentaerythritol triacrylate, trimethol propane propylene auxin triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and the like; Can be used in combination.

The photopolymerizable compound is preferably included in the content ratio of 1 to 20% by weight of the total composition, more preferably 5 to 15% by weight. If the photopolymerizable compound is included in less than 1% by weight, there may be a problem such that the pattern is dropped from the substrate during development due to insufficient curing at the time of forming the electrode pattern, and if it exceeds 20% by weight, the electrode pattern to be formed This may cause problems such as wider than the line width or sticking between wires.

Photopolymerization initiator

Examples of the photopolymerization initiator that can be used in the present invention include benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether, acetophenone and 2,2-dimethoxy-2. And acetophenones such as -phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone, and the like, and the like, and are not limited as long as they can form radicals by light. The photopolymerization initiators may be used alone or in combination of two or more thereof.

The photopolymerization initiator is preferably included in the content ratio of 0.1 to 10% by weight of the total composition, more preferably 0.5 to 5% by weight. When the photopolymerizable compound is included in less than 0.1% by weight, there may be a problem such that the pattern is dropped from the substrate during development due to insufficient curing at the time of forming the electrode pattern, and when it exceeds 10% by weight, the electrode pattern to be formed This may cause problems such as wider than the line width or sticking between wires.

solvent

The solvent in the present invention is not particularly limited, but an organic solvent capable of dissolving an organic binder and an organic additive may be used.

Examples of the organic solvent include methyl cellosolve, ethyl cellosolve, butyl cellosolve, texanol, terpineol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol Monobutyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethylene glycol, glycerol, butyl acetate, ethyl acetate, cyclohexanol, and the like, and these may be used alone or in combination.

The composition for forming a black layer according to the present invention preferably has a low viscosity of 10 to 200 cps so as to be applicable to the slit coating method, which is advantageous in obtaining a flat composition film. The low viscosity of 10 ~ 200cps can be implemented by adjusting the content of the solvent.

For this purpose, the content of the solvent is preferably included in the content ratio of 30 to 70% by weight of the total composition. When the solvent is contained in an amount ratio of less than 30% by weight, the content of solids becomes excessive so that the viscosity of the composition can not achieve the target viscosity of 200 cps or less, which makes it difficult to apply the slit coating method to form a flat coating film. Can not get On the other hand, if the content of the solvent exceeds 70% by weight due to the low solids it can not implement a predetermined coating film. Accordingly, the total content of the other materials except the solvent is also preferably 30 to 70% by weight of the total composition.

Etc

The composition for forming a black layer of the PDP electrode according to the present invention may further include a plasticizer in order to adjust the solubility of the organic binder in the solvent in addition to the above components. The plasticizer may be used to have compatibility in the organic binder, it is used for the purpose of adjusting the drying characteristics. Examples of the plasticizer may be one or more selected from the group consisting of phthalic acid esters, adipic acid esters, phosphate esters, trimellitic acid esters, citric acid esters, epoxy, polyesters, glycerol compounds, but are not necessarily limited thereto.

In addition, in the present invention, a dispersant, a viscosity stabilizer, an antifoaming agent, a coupling agent, and the like may be further added as necessary in addition to the above components.

The composition for forming a black layer of the PDP electrode according to the present invention uses a glass frit having an average particle diameter of 150 to 250 nm and a black pigment having an average particle diameter of 300 to 500 nm as described above, thereby causing the glass frit and the black pigment to settle in the composition. Problems that occur can be solved. Therefore, stability and aggregation resistance can be improved significantly.

How to Form Black Layer

The method of forming a black layer using the composition according to the present invention is accomplished through the steps of applying, drying and photolithography the composition.

In the application step, the composition is applied onto a glass substrate such as a transparent electrode using a slit coater.

In the drying step, the applied composition is dried to form a coating layer.

In the photolithography step, a black layer patterned by exposing a photomask on the coating layer using a photo mask, and then removing an exposed area (positive type) or an unexposed area (negative type) using a developer solution. To form.

Further, after the conductive layer is formed on the formed black layer by using an Off-Set Print method or a photolithography method, the conductive layer for forming the bus electrode is fired at the same time by simultaneously baking the black layer and the conductive layer, A bus electrode integrated with a black layer on a glass substrate such as a transparent electrode can be manufactured.

1 is an exploded perspective view showing a PDP prepared using the composition according to the present invention.

Referring to FIG. 1, the PDP 10 includes a front substrate 100 and a rear substrate 150.

The front substrate 100 facing the rear substrate 150 is formed with a transparent electrode 110 arranged in a transverse direction and a bus electrode 112 formed on the transparent electrode 110, and the transparent electrode 110. The MgO layer 118 is formed on the first dielectric layer 114 and the first dielectric layer 114 to store charges generated inside the panel and to facilitate electron emission.

At this time, the reason for forming the bus electrode 112 is to compensate for the transparent electrode 110 is formed of a metal oxide such as ITO, so the electrical conductivity is low and the response speed to various image signals is slow.

The black layer 111 manufactured by the composition according to the present invention may be formed under the bus electrode 112. The reason for forming the black layer 111 under the bus electrode 112 is generally the bus electrode 112. ) Is formed using silver (Ag) powder or other metal powder, and thus generally becomes white. As a result, the contrast ratio of the entire panel may drop, so that the bus electrode 112 may be as large as possible. This is to improve the contrast ratio of the entire panel by making it look closer to black.

At this time, the composition according to the present invention includes a black pigment and a glass frit having an average particle size of nano-class, and excellent sedimentation stability, and also because the composition is applied to the substrate by a slit coater, the loss of material is small, the thickness This has the advantage of minimizing change. Accordingly, the manufactured black layer 111 exhibits excellent roughness characteristics.

An address electrode 117 is formed on the rear substrate 150 facing the front substrate 100 in the longitudinal direction, and a second dielectric layer 115 is formed on the rear substrate 150 on which the address electrode 117 is formed. On the second dielectric layer 115, partition walls 120 in which fluorescent materials 132 corresponding to RGB are formed are formed in the second dielectric layer 115 to define pixel regions.

An inert gas such as Ne + Ar or Ne + Xe is injected into the space between the front substrate 100 and the rear substrate 150 to generate light by discharge when a voltage above a threshold voltage is applied to the electrode.

Example

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. However, this is presented as a preferred example of the present invention and in no sense can be construed as limiting the present invention.

Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

Preparation of Black Layer Formation Composition

≪ Example 1 >

As a black pigment, 4.6% by weight of cobalt oxide (Co ₂ O ₃ ) having an average particle diameter of 400 nm (Dmax = 1.2 μm), 5.5% by weight of glass frit having an average particle diameter of 200 nm (Dmax = 0.95 μm), an organic binder (P118, Nippon Goshei) 27.4% by weight, 2.6% by weight of photosensitive monomer (SR494, Sartomer), 5.2% by weight of photopolymerizable compound (TMPTA, Sartomer), 1.5% by weight of photopolymerization initiator (IC369, Ciba), dispersant (S333, BYK) 1.6 weight% and 51.6 weight% of solvents (PGMEA) were mix | blended, and it stirred in the high speed stirrer, and prepared the composition for black layer formation.

Comparative Example 1

Except for using black pigment, 4.6% by weight of cobalt oxide (Co ₂ O ₃ ) having an average particle diameter of 1.2 μm (Dmax = 4.5 μm) and 5.5% by weight of glass frit having an average particle diameter of 1.2 μm (Dmax = 3 μm) were used. According to the same method as in Example 1, a composition for forming a black layer was prepared.

Assessment Methods

Using the compositions of Example 1 and Comparative Example 1, the sedimentation rate, sedimentation occurrence, height uniformity and viscosity of the coating film were evaluated as follows.

1) Evaluation of Sedimentation Speed

The prepared black layer-forming composition was homogenized using a vibration mixer, and then 1 ml was collected using an aluminum dish with a dropper, and dried in an oven at 150 ° C. for 1 hour to measure an initial drying weight, and to evaluate the rate of settling. In order to inject and seal the composition in a 10 ml glass measuring cylinder, and left for 3 days in a place without vibration for 3 days, the upper 1ml was collected with a dropper and the dry weight was measured in the same manner as the above method.

Based on the dry weight measured as above, the relative sedimentation rate was calculated using the following equation.

Sedimentation rate = 100- (Dry weight after sedimentation) / (Initial dry weight) * 100 [Δ%]

2) Evaluation of sedimentation occurrence

Evaluation of the occurrence of sedimentation measured the height of the white band generated on the bottom surface of the 10 ml glass measuring cylinder left for 3 days.

3) Evaluation of Coating Film

The composition for forming a black layer prepared on a 10 cm × 10 cm high melting glass plate having a transparent electrode (ITO) was applied to a thickness of 40 μm using the slit coating method, and dried in a hot plate drying furnace adjusted to be maintained at 110 ° C. for 5 minutes. A black layer was formed, and the height uniformity was evaluated using the naked eye and a profiler.

4) Evaluation of Viscosity

The viscosity of the prepared black layer-forming composition was measured using a Brookfild DVII LV + viscometer.

Evaluation results

The results evaluated by the evaluation method are shown in Table 1 below.

TABLE 1

characteristic Example 1 Comparative Example 1 Sedimentation Speed [Δ%] One% 15% Sedimentation occurrence [mm] 0.06mm 2 mm Coating film Good Good Viscosity 52cps 48cps

Referring to the results of the relative sedimentation rate and sedimentation height in Table 1, the case of Example 1 using a glass frit having an average particle diameter of 200 nm and a black pigment having an average particle diameter of 400 nm is compared with the coarse particles corresponding to the prior art It can be seen that sedimentation stability is much better than that of Example 1.

Although the preferred embodiments have been described above by way of example, it is possible to make various modifications or variations without departing from the spirit and scope of the invention, and the appended claims include such modifications and variations that fall within the spirit of the invention.

1 is an exploded perspective view showing a PDP prepared using the composition according to the present invention.

Claims (9)

A black pigment having an average particle diameter of 300 nm to 500 nm, a glass frit having an average particle diameter of 150 nm to 250 nm, an organic binder, a photopolymerizable compound, a photopolymerization initiator, and a composition for forming a black layer of a PDP electrode. The method of claim 1, The black pigment is a composition for forming a black layer of the PDP electrode, characterized in that the maximum particle size is 0.6㎛ ~ 2㎛. The method of claim 1, The glass frit has a maximum particle size of 0.4㎛ ~ 1.5㎛ Black layer formation composition of the PDP electrode, characterized in that. The method of claim 1, The composition comprises 3 to 15% by weight of black pigment, 1 to 20% by weight of glass frit, 5 to 40% by weight of organic binder, 1 to 20% by weight of photopolymerizable compound, 0.1 to 10% by weight of photopolymerization initiator and residual amount. The composition for black layer formation of the PDP electrode characterized by the above-mentioned. The method of claim 1, The composition is a composition for forming a black layer of a PDP electrode, characterized in that the viscosity is 10 ~ 200cps. The method of claim 1, The black pigment is a composition for forming a black layer of a PDP electrode, characterized in that at least one of an oxide of a transition metal, a boride of a transition metal, a nitride of a transition metal and a carbide of a transition metal. The method of claim 1, The glass frit has a glass transition temperature of 200 ~ 500 ℃ a composition for forming a black layer of the PDP electrode, characterized in that. The method of claim 1, The organic binder is at least one of (i) a copolymer of a carboxyl group-containing monomer and a monomer having an ethylenically unsaturated double bond, ii) cellulose and (iii) a water-soluble cellulose derivative. A PDP electrode manufactured using the composition of any one of claims 1 to 8.

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