JP2004288581A - Photosensitive black paste for partition wall, member for plasma display, and plasma display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To particularly provide a photosensitive black paste without defect, a member for plasma displays and a plasma display by improving the formation of black partition walls used for contrast enhancement. <P>SOLUTION: In this photosensitive black paste for the partition wall, comprising an inorganic powder at least including a black powder and a glass powder, and an organic component including at least a photosensitive compound, the average particle diameter of the black powder is less than 2 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to forming a partition of a plasma display used for a wall-mounted television or a large monitor, and more particularly to a photosensitive black paste having no defects in forming a black partition, a member for a plasma display, and a plasma display.
[0002]
[Prior art]
2. Description of the Related Art As a display that can be used for a thin and large-sized television, a plasma display (hereinafter abbreviated as PDP) has attracted attention. A plurality of pairs of sustain electrodes are formed of a material such as chromium, aluminum, and nickel on a glass substrate on a front plate side serving as a display surface. Further, a dielectric layer mainly composed of glass is formed with a thickness of 20 to 50 μm to cover the sustain electrode, and an MgO layer is formed to cover the dielectric layer. On the other hand, a plurality of address electrodes are formed in stripes on the glass substrate on the back plate side, and a dielectric layer mainly composed of glass is formed so as to cover the address electrodes. A partition for partitioning the discharge cells is formed on the dielectric layer, and a phosphor layer is formed in a discharge space formed by the partition and the dielectric layer. A PDP capable of full-color display can be manufactured by forming a phosphor that emits light of each color of RGB as a phosphor layer. The front plate and the back plate are sealed so that the sustain electrodes of the glass substrate on the front plate side and the address electrodes on the back plate side are orthogonal to each other, and a rare material composed of helium, neon, xenon, or the like is provided in the gap between these members. Gas is sealed to form PDP. Since the pixel cell is formed around the intersection of the scan electrode and the address electrode, the PDP has a plurality of pixel cells and can display an image.
[0003]
When a voltage is applied between the sustain electrode and the address electrode from the state where no light is emitted in the selected pixel cell when the display is performed on the PDP and a voltage higher than the discharge start time of the sealing gas is applied, cations and electrons generated by ionization are generated in the pixel. Since the cell is a capacitive load, it moves in the discharge space toward the electrode of the opposite polarity and charges the inner walls of the MgO layers on both sides, and the charges on the inner walls are not attenuated due to the high resistance of the MgO layer. Remains. An electric field having a polarity opposite to that of an externally applied voltage is formed in the discharge space by the wall charges, so that the electric field in the cell is weakened and the discharge stops immediately.
[0004]
Next, the discharge is maintained by applying a discharge maintaining voltage between the scan electrodes.
The discharge at a voltage lower than the discharge start voltage is continued by the wall charges. This discharge excites the xenon gas in the discharge space, generating ultraviolet rays of 147 nm, and the ultraviolet rays excite the phosphor, thereby enabling light-emitting display.
[0005]
The shape of the partition walls is about 30 to 80 μm in width and about 100 to 200 μm in height. Usually, an insulating paste made of glass is printed and dried by a screen printing method, and this printing and drying is repeated 10 to 20 times. After a predetermined height, it is formed by firing. However, the ordinary screen printing method has a problem that it is difficult to align with the address electrodes particularly when the panel size is large, and it is difficult to obtain the positional accuracy. In addition, by performing the superposition printing of the glass paste 10 to 20 times, the ribs and the side edges of the partition wall and the edge of the wall are disturbed, and the accuracy of the height cannot be obtained, so that the display quality deteriorates. There are problems of poor workability and low yield. In particular, when the pattern width is 50 μm and the pitch is 100 μm or less, there is a problem that the bottom of the partition wall is easily spread due to the thixotropy of the paste, and it is difficult to form a sharp and residue-free partition wall.
[0006]
With the increase in the area and resolution of PDPs, such a screen printing method has made it increasingly difficult and costly to manufacture partition walls having a high aspect ratio and high definition. .
[0007]
As a method of improving these problems, a method of forming a partition using a photosensitive glass paste method has been proposed (for example, see Patent Document 1). That is, by using photolithography, it is possible to manufacture a partition having a high aspect ratio and a high definition. However, in this method, since the partition walls are white, there is a problem that the contrast is insufficient when used for a plasma display.
Therefore, a method of forming a black partition using a photosensitive glass paste containing a metal or a metal oxide has been proposed, but it has not been sufficient to form a black partition without defects (for example, see Patent Document 2). .
[0008]
[Patent Document 1]
JP-A-8-50811 (pages 3 to 12)
[0009]
[Patent Document 2]
JP-A-10-182185 (pages 3 to 12)
[0010]
[Problems to be solved by the invention]
Therefore, the present invention has been made in view of the above-described problems in the conventional technology, and an object of the present invention is to improve the formation of black partition walls used for improving contrast in a plasma display, and to provide an excellent defect-free method. To provide a photosensitive black paste, a member for a plasma display, and a plasma display.
[0011]
[Means for Solving the Problems]
That is, in order to solve the above problems, the present invention is a photosensitive black paste for the partition wall comprising an organic component containing at least a photosensitive compound and an inorganic powder containing at least a black powder and a glass powder, the average particle diameter of the black powder is A photosensitive black paste for a partition, which is less than 2 μm. Further, a member for a plasma display of the present invention is characterized by using the above photosensitive black paste.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
The inorganic powder constituting the photosensitive black paste of the present invention needs to include at least a black powder and a glass powder. The inclusion of at least black powder in the inorganic powder is necessary to color the partition walls black. Glass powder is an essential component for forming a partition layer by a firing step after pattern formation.
[0013]
The maximum particle size of the black powder used in the present invention is preferably 20 μm or less. When the maximum particle diameter exceeds 20 μm, a portion where light is largely blocked at the time of exposure may be formed, and a defective portion may be generated in the pattern. It is because it may cause. Here, the particle diameter is a value measured by a laser scattering / diffraction method, the average particle diameter is a 50% volume particle diameter, and the maximum particle diameter is the maximum value of the particle diameter.
[0014]
Further, it is preferable that the average particle diameter of the black powder is less than 2 μm in that a defect-free partition can be formed. If the average particle diameter is 2 μm or more, the partition walls tend to be chipped during the formation of the partition walls, so that erroneous discharge may occur when the panel is sealed to the front plate.
[0015]
As the black powder, at least one metal selected from the group consisting of Ru, Cr, Fe, Co, Mn, Cu and Ni, or an oxide thereof is preferably used. Among them, it is more preferable to use Ru.
[0016]
The amount of the black powder is preferably 0.5 to 10 parts by weight in the photosensitive black paste. If the amount is less than 0.5 parts by weight, the blackness is weakened and the image looks grayish, and there is no effect in improving the contrast. If the amount is more than 10 parts by weight, the softening point of the glass may increase, or it may be difficult to match the coefficient of thermal expansion with the glass substrate. Further, the blackness becomes too strong, so that the ultraviolet rays hardly reach the lower portion, and the pattern formability is sometimes lowered, which is not preferable.
[0017]
Further, the particle size of the glass powder used in the present invention is selected in consideration of the shape of the pattern to be produced. However, the average particle size is preferably in the range of 0.5 to 5 μm to form the pattern of the partition wall. It is preferable in forming. If the average particle diameter is larger than 5 μm, surface irregularities may occur during high-precision pattern formation. More preferably, it is in the range of 2 to 5 μm.
[0018]
Regarding the black powder and the glass powder of the present invention, when the average particle diameter of the black powder is Db and the average particle diameter of the glass powder is Dg, it is important to satisfy the expression of 0.01 <Db / Dg <1. is there. Thereby, an excellent black partition wall for a plasma display having no defect can be obtained.
[0019]
The glass powder used in the present invention preferably contains at least one of silicon and boron oxides.
When silicon oxide is contained as a component constituting the glass powder, it is preferable that the compounding ratio of silicon oxide is 3 to 60 parts by weight based on the total amount of the powder. When the compounding ratio is less than 3 parts by weight, the denseness, strength and stability of the glass layer may be reduced, the thermal expansion coefficient may be out of a desired value, and a mismatch with the glass substrate may easily occur. . On the other hand, if it exceeds 60 parts by weight, the thermal softening point tends to be high, and it tends to be difficult to bake on a glass substrate.
When boron oxide is contained as a constituent of the glass powder, it may be blended in a range of 5 to 50 parts by weight based on the total amount of the powder, to obtain an electric insulating property, strength, coefficient of thermal expansion, denseness of the insulating layer, etc. Preferred for further improvement of mechanical and thermal properties. If it exceeds 50 parts by weight, the stability of the glass may be reduced.
[0020]
As such a glass powder, bismuth oxide, lead oxide, and a glass paste having a temperature characteristic that can be patterned on a glass substrate by using glass fine particles containing at least one kind of zinc oxide in an amount of 5 to 50 parts by weight are used. Obtainable. In particular, when a glass powder containing 5 to 50 parts by weight of bismuth oxide is used, advantages such as a long pot life of the paste can be obtained.
[0021]
As the bismuth-based glass fine particles, it is preferable to use a glass powder having the following composition.
Bismuth oxide: 10 to 40 parts by weight Silicon oxide: 3 to 50 parts by weight Boron oxide: 10 to 40 parts by weight Barium oxide: 8 to 20 parts by weight Aluminum oxide: 10 to 30 parts by weight Lithium oxide, sodium oxide, potassium oxide Among them, a glass powder containing at least one kind in an amount of 3 to 20 parts by weight with respect to the total powder amount may be used, but in this case, the addition amount of an alkali metal oxide such as lithium, sodium, and potassium is added to the total powder amount. When the content is 20 parts by weight or less, preferably 15 parts by weight or less, the stability of the paste can be improved.
[0022]
As a specific glass powder in this case, it is preferable to use a glass powder having the following composition.
Lithium oxide: 2 to 15 parts by weight Silicon oxide: 15 to 50 parts by weight Boron oxide: 15 to 40 parts by weight Barium oxide: 2 to 15 parts by weight Aluminum oxide: 6 to 25 parts by weight In the above composition, instead of lithium oxide In addition, sodium oxide and potassium oxide can be used, but lithium oxide is preferred from the viewpoint of paste stability.
Further, if glass fine particles containing both a metal oxide such as lead oxide, bismuth oxide and zinc oxide and an alkali metal oxide such as lithium oxide, sodium oxide and potassium oxide are used, a lower alkali content can be obtained. Thermal softening temperature and linear expansion coefficient can be easily controlled.
[0023]
In addition, workability is improved by adding aluminum oxide, barium oxide, calcium oxide, magnesium oxide, titanium oxide, zinc oxide, zirconium oxide, and the like, particularly, aluminum oxide, barium oxide, and zinc oxide to the glass powder. However, the content is preferably 40 parts by weight or less, and more preferably 25 parts by weight or less, from the viewpoint of controlling the thermal softening point and the coefficient of thermal expansion.
[0024]
The organic component constituting the photosensitive black paste of the present invention needs to contain at least a photosensitive compound.
[0025]
As the photosensitive compound, there are a photo-insolubilizing type and a photo-solubilizing type. As the photo-insolubilizing type, (A) a functional monomer oligomer or polymer having at least one unsaturated group or the like in a molecule is used. Containing, (B) a compound having a photosensitive compound such as an aromatic diazo compound, an aromatic azide compound, and an organic halogen compound; and (C) a so-called diazo resin such as a condensate of a diazo amine and formaldehyde. is there. Examples of the photo-solubilizing type include (D) a complex of an inorganic salt or an organic acid of a diazo compound, a quinone diazo-containing compound, and (E) a quinone diazo compound obtained by bonding a quinone diazo compound to an appropriate polymer-binder. And a novolak resin, naphthoquinone-1,2-diazido-5-sulfonic acid ester. In the present invention, the photosensitive resin compound may be any one of the above, but is preferably a light-insoluble type, and particularly preferably the above (A), because it can be easily mixed with inorganic particles and used.
[0026]
Specific examples of the photosensitive monomer include compounds having an active carbon-carbon double bond, and monofunctional and polyfunctional compounds having a vinyl group, an acryl group, an acrylate group, a methacrylate group, and an acrylamide group as functional groups. Is mentioned. In particular, a compound containing a polyfunctional acrylate compound and a methacrylate compound in an amount of 10 to 80 parts by weight in an organic component is preferable in that the photoreaction increases the crosslink density at the time of curing and improves the pattern formability. Since various types of compounds have been developed as the polyfunctional acrylate compound and methacrylate, they can be appropriately selected in consideration of reactivity, refractive index, and the like. The acid value (AV) of the polymer or oligomer is preferably from 50 to 180, and more preferably from 70 to 140, from the viewpoint of the development allowance and the solubility of the unexposed portion in the developing solution. Further, by adding a photoreactive group to a side chain or a molecular terminal to the polymer or oligomer described above, a photosensitive polymer or tourist oligomer having photosensitivity is obtained, and it is most preferable to use this. At this time, the photoreactive group preferably has an ethylenically unsaturated group, and examples of the ethylenically unsaturated group include a vinyl group, an allyl group, an acryl group, and a methacryl group.
[0027]
Further, if necessary, a binder, a photopolymerization initiator, an ultraviolet absorber, a sensitizer, a sensitization aid, a polymerization inhibitor, a plasticizer, a thickener, an organic solvent, an antioxidant, a dispersant, and an antifoaming agent. Additive components such as organic or inorganic suspending agents can also be added.
[0028]
Next, pattern processing is performed using the photosensitive black paste of the present invention.
First, a photosensitive black paste is applied entirely or partially on a glass substrate or a ceramic substrate. As a coating method, a method such as screen printing, a bar coater, a roll coater, a die coater, and a blade coater can be used. The coating thickness can be adjusted by selecting the number of coatings, the screen mesh, and the viscosity of the paste.
[0029]
After the application, exposure is performed using an exposure device. Exposure is generally performed by a mask exposure using a photomask, as performed by ordinary photolithography. As the mask to be used, either a negative type or a positive type can be selected depending on the type of the photosensitive organic component. Alternatively, a method of directly drawing with red or blue laser light without using a photomask may be used.
[0030]
As the exposure device, a stepper exposure device, a proximity exposure device, or the like can be used. In the case of performing exposure over a large area, a large area can be exposed by an exposure machine having a small exposure area by applying a photosensitive paste on a substrate such as a glass substrate and then performing exposure while transporting the photosensitive paste. The active light source used at this time includes, for example, visible light, near-ultraviolet light, ultraviolet light, electron beam, X-ray, and laser light, and among these, ultraviolet light is particularly preferable from the photoreaction characteristics of the photosensitive compound. As the light source, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a halogen lamp, a germicidal lamp and the like can be used. Among these, an ultra-high pressure mercury lamp is preferred. Exposure conditions vary depending on the coating thickness, but usually exposure is performed for 0.5 to 30 minutes using an ultrahigh pressure mercury lamp having an output of 1 to 50 mW / cm2.
[0031]
After the exposure, development is carried out by utilizing the difference in solubility between the photosensitive portion and the non-photosensitive portion in a developing solution, which is usually performed by an immersion method, a shower method, a spray method, a brush method or the like. As a developer to be used, an organic solvent in which an organic component in the photosensitive paste can be dissolved can be used. Water may be added to the organic solvent as long as its solubility is not lost. When a compound having an acidic group such as a carboxyl group is present in the photosensitive paste, development can be performed with an aqueous alkali solution. As the alkali aqueous solution, a metal alkali aqueous solution such as sodium hydroxide, sodium carbonate, calcium hydroxide aqueous solution or the like can be used, but it is preferable to use an organic alkali aqueous solution since the alkali component can be easily removed at the time of firing.
[0032]
As the organic alkali, an amine compound can be used. Specific examples include tetramethylammonium hydroxide, trimethylbenzylammonium hydroxide, monoethanolamine, diethanolamine and the like. The concentration of the alkaline aqueous solution is usually 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight. If the alkali concentration is too low, the soluble portion is not removed, and if the alkali concentration is too high, the pattern portion may be peeled off and the non-soluble portion may be corroded, which is not preferable. The development temperature during development is usually preferably from 20 to 50 ° C. from the viewpoint of process control.
[0033]
Next, firing is performed in a firing furnace. The firing atmosphere and temperature vary depending on the type of paste or substrate, but firing is performed in an atmosphere such as air, nitrogen, or hydrogen. As the firing furnace, a batch-type firing furnace or a belt-type continuous firing furnace can be used. When patterning is performed on a glass substrate, baking is usually performed at a temperature of 540 to 610 ° C. for 10 to 60 minutes. A heating step at a temperature of 50 to 300 ° C. may be introduced for the purpose of drying and preliminary reaction during each of the coating, exposure, development and baking steps.
[0034]
By forming a phosphor layer that emits light of each color of RGB on the substrate on which the partition walls are formed, and baking at 400 to 550 ° C. as necessary, a member for a plasma display can be manufactured. Furthermore, using the plasma display member as the back substrate, after sealing with the front substrate, filling a discharge gas composed of helium, neon, xenon, etc. in the space formed between the front and back substrates, and then driving the circuit. A plasma display can be manufactured by mounting.
[0035]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples. However, the present invention is not limited to this. The concentrations in Examples and Comparative Examples are parts by weight unless otherwise noted.
(Example 1)
First, the particle size of the black powder used was measured. A powder obtained by mixing manganese oxide and copper oxide at a ratio of 1: 1 was used as the black powder.
The measuring method is as follows.
Measuring device: Microtrac HRA particle size analyzer (Model No. 9320-X100)
Sample amount: 1g
Dispersion conditions: Ultrasonic dispersion was performed with purified water for 1.5 minutes.
Solvent refractive index: 1.0
Number of measurements: As a result of two measurements, the average particle diameter was 1.2 μm and the maximum particle diameter was 15.3 μm.
The composition of the glass powder is 5 parts by weight of lithium oxide, 25 parts by weight of silicon oxide, 35 parts by weight of boron oxide, 5 parts by weight of barium oxide, and 20 parts by weight of aluminum oxide. The average particle size is 2.2 μm.
1 part by weight of this black powder and 99 parts by weight of glass powder were used as inorganic powder.
[0036]
First, a back plate of a plasma display was manufactured.
Address electrodes were formed on a glass substrate (PD200 manufactured by Asahi Glass Co., Ltd.) using a photosensitive silver paste. An address electrode having a line width of 50 μm, a thickness of 3 μm, and a pitch of 250 μm was formed through the steps of applying a photosensitive silver paste, drying, exposing, developing, and baking.
[0037]
Next, a dielectric layer was formed on this electrode. The dielectric paste was formed by kneading 70 parts by weight of an inorganic component, 20 parts by weight of ethylcellulose, and 10 parts by weight of terpineol by a screen printing method so as to cover the address electrodes in the display area by screen printing, and then 570 ° C. Firing was performed for 15 minutes to form a back dielectric. The dielectric thickness after firing was 11 μm.
[0038]
Partition walls were formed on the dielectric by a photosensitive paste method.
After applying the photosensitive black paste composed of the inorganic powder and the photosensitive organic component, exposure is performed using a photomask having an opening line width of 30 μm, and then developed in a 0.5 part by weight aqueous ethanolamine solution. By baking at 560 ° C. for 15 minutes, a partition having a pitch of 250 μm, a line width of 30 μm, and a height of 130 μm was formed. When the formed partition was inspected with an optical microscope, it was found that the partition had no defect such as disconnection or chipping. Next, a phosphor was applied between adjacent partition walls. The phosphor was applied by a dispenser method in which a phosphor paste was discharged from a nozzle tip having 256 holes (having a diameter of 130 μm). The phosphor was applied on the side wall of the partition wall so as to have a thickness of 25 μm after firing and on a dielectric material so as to have a thickness of 25 μm after firing, followed by firing at 500 ° C. for 10 minutes. A visual inspection with an optical microscope and a luminescence inspection using a UV lamp irradiating a wavelength of 254 nm after the formation of the phosphor showed no color mixing.
[0039]
Further, the produced front substrate and rear substrate were sealed using sealing glass, and a Ne gas containing 5% of Xe was sealed so as to have an internal gas pressure of 66500 Pa. Further, a driving circuit was mounted to produce a PDP. Light was emitted by applying a voltage to the bus electrode of the PDP. The produced plasma display was free from defects such as abnormal discharge and extra points.
[0040]
(Example 2)
Performed in the same manner as in Example 1 except that 5 parts by weight of black powder (the same component as in Example 1) having an average particle diameter of 1.8 μm and a maximum particle diameter of 19 μm and 95 parts by weight of glass powder having an average particle diameter of 2.8 μm were used. Was.
The produced plasma display had no defects such as abnormal discharge or extra dots.
[0041]
(Example 3)
Example 1 was repeated except that ruthenium oxide (average particle diameter 1.2 µm, maximum particle diameter 18 µm) was used as a black powder component. The produced plasma display had no defects such as abnormal discharge or extra dots.
[0042]
(Example 4)
The same procedure as in Example 1 was carried out except that a powder (average particle diameter: 1.0 μm, maximum particle diameter: 16 μm) in which chromium oxide, cobalt oxide and nickel oxide were mixed at a ratio of 1: 2: 1 was used as a black powder component. The produced plasma display had no defects such as abnormal discharge or extra dots.
[0043]
(Comparative Example 1)
The procedure was performed in the same manner as in Example 1 except that a black powder having an average particle diameter of 4.4 μm and a maximum particle diameter of 38 μm was used. When the formed partition wall was inspected with a microscope, it was found that there were 15 breaks in the partition wall and 12 breaks in the partition wall. Further, the plasma display produced by applying the phosphor layer and sealing it with the front substrate was a plasma display having many abnormal discharges at 12 places and an extra 9 places.
[0044]
【The invention's effect】
By using the photosensitive black paste of the present invention, an excellent black partition for a plasma display without defects can be formed by a simple method.
[Brief description of the drawings]
FIG. 1 is a cross-sectional perspective view of a general PDP.
1: Glass substrate 2, 3: Bus electrode 4: Dielectric layer 5: MgO layer 6: Glass substrate 7: Address electrode 8: Dielectric layer 9: Partition 10: Phosphor layer

Claims (7)

A photosensitive black paste for partition walls comprising an inorganic powder containing at least black powder and glass powder and an organic component containing at least a photosensitive compound, wherein the average particle diameter of the black powder is less than 2 μm. Black paste. The photosensitive black paste for a partition according to claim 1, wherein the maximum particle size of the black powder is 20 µm or less. The black powder contains at least one metal selected from the group consisting of Ru, Cr, Co, Mn, Cu and Ni or an oxide thereof in a range of 0.5 to 10 parts by weight. 2. The photosensitive black paste for partition walls according to 1. The formula of 0.01 <Db / Dg <1 is satisfied, where Db is the average particle diameter of the black powder and Dg is the average particle diameter of the glass powder. Photosensitive black paste for partition walls. The photosensitive black paste for a partition according to any one of claims 1 to 4, wherein an average particle diameter of the glass powder is in a range of 2 to 5 µm. A member for a plasma display, wherein the top or the whole of a partition is formed using the photosensitive black paste for a partition according to any one of claims 1 to 5. A plasma display using the photosensitive black paste for a partition according to any one of claims 1 to 5.

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