JP2001047364A - Method of forming rib for plazma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reuse a sand blast waste material by removing abrasive particles from the sand blast waste material, that is, a mixture powder of the abrasive particles and the abrasive powder of a rib forming material, and repasting the same while adjusting overs and shorts of components. SOLUTION: In a cyclone 12, a reusable abrasive material is classified into an abrasive material including a partially reusable crushed abrasive material and the dust as the broken pieces of a rib forming material ground out from a board. The reusable abrasive material is stored in a distributor 13 mounted at a lower part of the cyclone 12, on the other hand, the dust is raised by the air current at a central part in the cyclone 12 to be fed to a dust collector 15 through a duct 14 communicated with an upper central part. The dust recovered in a dust tank 21 of the dust collector 15 is classified into the coarse powder (reusable abrasive material) and the fine powder (chip of abrasive material and ground rib powder) by a dry-type classifier. Here, the classified coarse powder is reused as the abrasive material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for manufacturing a plasma display panel (hereinafter referred to as "PDP"), and more particularly to a technical field of forming a rib constituting a discharge space of a PDP by a sandblasting method. .

[0002]

2. Description of the Related Art In general, a sand blasting method has been used as one of processing methods for forming a pattern on a surface of a base material such as glass, marble, plastic, ceramics, leather, and wood. In this processing method, a resist for sandblasting is provided on the surface of a base material, and a grinding material or the like is sprayed on an exposed portion of the resist to selectively grind to form a design. Then, using a photosensitive resin with sandblast resistance as a sandblasting resist, forming a mask pattern by a photolithography method, and then spraying an abrasive or the like on the exposed portion to process the exposed portion, since the fine processing can be performed It is used for forming a circuit board in which a metal pattern and an insulating pattern are mixed, particularly for forming a metal wiring pattern of a PDP and an insulating pattern such as a rib and a phosphor.

A PDP has a cell structure or a line structure including barrier ribs and priming ribs formed on a substrate such as glass, an electrode and a phosphor layer are provided in the cell structure or between the line structures, and a discharge gas is filled. It is manufactured by forming a display element. Such a cell structure or line structure is composed of a low-melting glass powder, an inorganic powder such as a refractory filler as a main component or a component, and a rib forming paste obtained by adding an appropriate binder resin and a solvent to the substrate. A rib forming material layer is formed by coating and drying, and a photosensitive resin composition layer having sand blast resistance is provided thereon, and then patterned into a cell defining mask by a photolithography method, and sand blasting is performed through the mask. It is formed by performing processing, removing and removing the mask, and then firing. In the sandblasting, glass beads having a particle size distribution of about 2 to 50 μm, SiC, S
Abrasives of inorganic fine particles such as iO ₂ , Al ₂ O ₃ and ZrO ₂ have been used.

[0004]

Recently, there has been an increasing demand for PDPs to be larger, have higher definition, have higher brightness, and have a longer life. In order to meet these demands, low-melting glass ribs are formed on a substrate such as glass by sand blasting to reduce the rib width and increase the uniformity and increase the phosphor application area. Development is underway. Incidentally, PDP has a rib width of about 50 μm and a rib height of 150 to 20 as an example.
The gap between the ribs is about 100 μm at 0 μm. Along with this, the particle size distribution is 2 to 2 as sandblasted abrasive.
If inorganic fine particles of about 50 μm were used, high quality ribs could not be formed, which had a great adverse effect on the performance of PDP.

Further, when the above-mentioned inorganic fine powder abrasive is used, a large amount of the fine powder of the abrasive and the ground powder of the barrier rib material are generated during sandblasting, and it is difficult to separate the two. The only option is to discard, but this has been a major environmental and cost problem.

The present invention has been made in view of such a problem, and an object of the present invention is to effectively reuse sandblast waste generated during grinding when patterning ribs of a PDP by a sandblast method. An object of the present invention is to provide a method for forming a rib of a PDP.

[0007]

In order to achieve the above object, the present invention provides a method for forming a rib-forming material layer by applying a rib-forming paste on a substrate and drying the paste. Including a step of forming a mask pattern having a pattern, and grinding the exposed portion of the rib forming material layer by sandblasting using a sandblasting abrasive.
In the rib forming method of P, after the rib forming material layer is ground by a sand blast method using a sand blasting abrasive, a mixed powder of the abrasive particles mixed during sand blasting and the grinding powder of the rib forming material is classified. Thus, the abrasive material particles are removed from the mixed powder, the excess and deficiency components are adjusted and re-pasted, whereby the rib material is recovered and reused.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, it is desirable to use, as the abrasive, a substance which can be easily separated from the sandblast waste material and which can be used for adjusting the composition at the time of frit, for the fine powder abrasive which cannot be separated. By performing sandblasting using such an abrasive, it is possible to reuse sandblast waste.

It is important that the sandblasted abrasive is a classified powder having a predetermined particle size distribution together with the material constituting the sandblasted abrasive, and is further adjusted by a predetermined classification means. Preferably, there is. PDP
In order to respond to large size, high definition, high brightness, and long life,
It is important how well the ribs are made without defects or that no defective reserves are created. When the particle size of the abrasive is less than 2 μm, the grinding ability is low, and when it exceeds 25 μm, especially when the maximum particle size exceeds 40 μm, the generation of rib defects or defect reserves becomes remarkable, and Formation becomes difficult.

The raw material components of sandblasted abrasives are usually obtained in a state where the particle size distribution is wide, but it is desirable to obtain a material having a substantially uniform particle size, and to obtain a powder having the above-mentioned particle size distribution. In order to do this, put it on a dry classifier. Specifically, it is preferable to cut the coarse powder and the fine powder using a dry classifier (for example, “Toroplex” manufactured by Hosokawa Micron) in order to make the particle size uniform. In addition,
There is a method of classifying and accurately obtaining a powder that maintains the maximum particle powder, but is not preferred because pulverization lowers the plasticity of the material powder.

In the present invention, an ordinary method is employed for forming the ribs of the PDP. First, a rib forming material layer is formed by applying and drying a rib forming paste on a substrate, and a photosensitive resin composition layer having sandblast resistance is provided thereon, and then activated through a photomask. By selectively irradiating a light beam and subsequently developing, a sand blast mask pattern is formed, and the exposed portion of the rib forming material layer is ground with the above sand blast abrasive. In this case, the injection pressure is preferably 1.0 to 3.0 kg / cm ² and the injection amount is 5 to 10 as in the case of the ordinary sandblast method.
Sandblasting is performed by spraying at 0 g / min.

In sandblasting, since the abrasive itself has high strength and toughness, it does not easily become fine powder such as chips. On the other hand, since the ground rib-forming material has a small particle size of about 1 μm, by classifying a powder mixture of the grinding material particles generated during sand blasting and the grinding powder of the rib-forming material, the grinding material particles are reduced from the mixed powder. Can be removed. However, even if a high-toughness material is used as the abrasive, fine powder is generated to some extent, and the fine powder of the abrasive mixes with the shaved rib-forming material. Solvable.

FIG. 1 shows an example of a flow of recovering the rib forming material. The rib-forming paste is a paste having a composition in which an inorganic powder such as a low-melting glass powder and a refractory filler is a main component or a component, and an appropriate binder resin and a solvent are added thereto. In order to produce this paste, first, an inorganic powder mixed with a low-melting glass powder, a refractory filler, a pigment and the like is pulverized by a ball mill to adjust the particle size thereof. Next, the crushed inorganic powder is sieved to remove large-sized ones, and dried to complete a frit, and a binder resin and a solvent are added to the frit to form an ink, thereby obtaining a paste. Then, as described above, the rib forming paste is applied to the substrate and dried to form a rib forming layer, and a sand blasting mask is formed thereon, and then the abrasive is sprayed from the spray nozzle. Then, sandblasting is performed. Grinding powder generated during sandblasting is collected and classified into a coarse powder side and a fine powder side by a cyclone attached to the blast. Since the coarse powder side is an abrasive, it is reused as it is. on the other hand,
The fine powder side consists of a part of the abrasive, crushed abrasive, and fragments of the rib-forming material ground from the substrate. Separated from the rib forming material. Some of these abrasives are reused as abrasives. In addition, crushed abrasive and rib material are mixed with crushed abrasive,
The composition is adjusted and reused to produce a repaste.

In preparing the re-paste, since the resin is already mixed in the rib material on the collected fine powder side, it is necessary to adjust not only the frit composition but also the amount of the resin in the composition adjustment. Therefore, the method of preparing the repaste is different from a new one, and after mixing the vehicle with the insufficient component and the corresponding diluent solvent into the resin-mixed frit to form a paste,
A new paste is mixed at a predetermined ratio.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to a series of steps for forming high-definition ribs on a PDP substrate.

(Step of Forming Electrode Layer) The planar size is 1
A glass substrate having a size of 000 × 600 mm and a thickness of 2.8 mm is prepared, and a large number of parallel striped electrodes are formed on one surface of the glass substrate at an interval of 150 μm by screen printing.

(Step of forming rib-forming material layer) A low-melting-point glass paste using a cellulose-based resin or an acrylic-based resin as a binder is collectively coated on the entire surface of the glass substrate on the electrode side by a die coater. Dry for a minute and solidify to form a rib-forming material layer. Since the low-melting-point glass layer is formed from a low-melting-point glass paste using a cellulose-based resin or an acrylic-based resin as a binder, the grinding property by blasting (hereinafter referred to as blasting property) is extremely good.

(Step of forming a mask for sandblasting) A dry film ("Audil BF603" manufactured by Tokyo Ohka Kogyo Co., Ltd.) is laminated on the entire surface of the rib forming material layer.
Exposure and development were performed to form a patterned resist layer on the rib forming material layer as a sandblast mask.
As the developing solution, a 0.2% aqueous solution of sodium carbonate is used. Note that the pattern of the resist layer in this example has a parallel stripe shape with a width of 50 μm and an interval of 100 μm. did. Alternatively, a sandblasting mask is formed by applying a pattern of a blast-resistant low-melting glass paste to a thickness of 27 μm by screen printing and drying without using the above-mentioned dry film. As the blast-resistant low-melting glass paste, one that completely burns so that carbon and tar of each binder do not remain on the ribs even when fired in a step described later.

(Sand blasting process) The substrate is transported on a number of transport rollers and is loaded into the blasting chamber. Then, a sandblast abrasive is sprayed from a spray nozzle toward the rib forming material layer and the resist layer side of the workpiece having the rib forming material layer and the resist layer formed on the surface of the substrate, that is, the glass substrate. Eight injection nozzles are provided that are capable of reciprocating in a direction perpendicular to the direction of transport of the workpiece. Each spray nozzle is a diffusion-type spray nozzle, which diffuses the abrasive shape of the abrasive three times as much as usual. Even if the blast processing speed is increased by the combination of the substrate transfer speed and the moving speed of each spray nozzle, Processing uniformity can be maintained. The powder used as the sand-blasting abrasive for forming ribs in this embodiment is obtained by classifying zirconia powder.

In the processing chamber, a sandblasting abrasive mainly composed of zirconia is sprayed together with the compressed air onto the glass substrate on the side of the resist layer and the rib forming material layer together with the compressed air, thereby excluding the rib forming material layer immediately below the resist layer. A rib is formed by grinding and removing a part of the rib forming material layer. The rib thus formed has a width of 50 μm and a height of 150 μm.
The spacing between the ribs is 100 μm. Specifically, when a sandblast abrasive is injected from the injection nozzle to the resist layer and the rib-forming material layer side of the substrate in the blasting chamber, the rib-forming material layer immediately below the resist layer is protected by the resist, so the abrasive material is used. Although not ground or engraved, all portions of the rib forming material layer other than the rib forming material layer immediately below the resist layer are ground and removed. The grinding speed at that time is
Conventionally used glass beads, SiC, SiO ₂ ,
A high-quality rib can be formed faster than a grinding material of inorganic fine particles of about _{2 to} 50 μm such as Al ₂ O ₃ and the particle size is controlled. Therefore, as a result, as shown in the pattern of the resist layer, a plurality of ribs having a width of 50 μm and a height of 150 μm have an interval between each rib of 100 μm.
It is formed in a parallel stripe shape of μm.

(Rib forming material recovery step) The abrasive sprayed from the spray nozzle toward the substrate becomes a mixed powder with the grinding powder of the rib forming material, falls into a hopper below the blasting chamber, and is Is carried to the separation tank by the airflow generated in the conduit from the lower end. Then, the foreign matter having a size of 100 μm or more mixed in the abrasive is removed by the separation tank, and is then sent to the cyclone via the communication pipe. The air flow in the blasting chamber is generated by suction of air by a blower of a dust collector. That is, the air flow is in the order of hopper, conduit, separation tank, communication pipe, cyclone,
It flows to the dust collector.

FIG. 2 is a schematic structural view showing an example of a cyclone and a dust collecting device incorporated in the step of collecting the rib forming material. The mixed powder that has fallen from the blasting chamber to the hopper and has a foreign matter having a size of 100 μm or more removed in the separation tank is transported to the cyclone 12 through the communication pipe 11. In the cyclone 12, reusable abrasives, and some reusable abrasives, crushed abrasives, and dust made of pieces of rib forming material ground from the substrate are classified. The reusable abrasive stays in the distributor 13 below the cyclone 12, while the dust rises in the center of the cyclone 12 by airflow and passes through the duct 14 communicating with the upper center. 15 and the dust collecting device 15
Then, dust is collected and clean air is discharged into the atmosphere by the blower 16. The abrasive remaining in the distributor 13 below the cyclone 12 is collected in an abrasive tank 17 connected to the lower end of the cyclone, and the abrasive in the abrasive tank 17 is supplied to the nozzle portion again. The abrasive is drawn by the compressed air in the nozzle portion and is ejected from the ejection nozzle 18 together with the compressed air. In this way, the abrasive is injected from the injection nozzle 18 toward the substrate by repeating the above steps, and is subjected to blast processing.

Since the classification in the cyclone 12 is performed under the condition that only the reusable abrasive is accumulated on the distributor 13 side, as described above, the one sent to the duct 14 is the same as the reusable abrasive. It becomes a mixed powder of the fragments of the abrasive and the ground rib powder. The reason is that if powders other than reusable abrasives are mixed, the blast conditions fluctuate, and high-quality ribs cannot be produced for the reasons described above. Therefore, it is necessary to classify the mixed powder separately.

In the dust collector 15, dust is attached to the surface of the filter 15a. Therefore, Cyclone 12
The valve 19 in the duct 14 between the dust collector 15 and the dust collector 15 is closed, and the valve 20 between the dust collector 15 and
And dust is attached to the surface of the filter 15a to drop and collect in the dust tank 21 below. The dust collected in the dust tank 21 of the dust collector 15 in this way is subjected to coarse powder (reusable abrasive) and fine powder (reusable abrasive) using a dry classifier (for example, Hosokawa Micron “Turboplex”). Classify the fragments of the abrasive and the ground rib powder. Here, the separated coarse powder is reused as an abrasive, and the fine powder is subjected to composition adjustment as described above and is recycled, so that powder composed of pieces of the rib-forming material ground from the substrate is reliably collected. Can be reused.

(Firing Step) The workpiece on which the ribs are formed on the surface of the glass substrate is gradually heated to a temperature at which the low-melting glass lead glass is completely melted and the binder is incinerated, thereby forming the ribs. The low melting glass and the binder of the resist are completely burned, and the low melting glass is melted and fired to form ribs.

[0026]

As described above, according to the present invention,
Recover and reuse the rib material by removing the abrasive particles from the sandblast waste material, which is a mixture of the abrasive particles and the grinding powder of the rib-forming material, adjusting the excess and deficiency components, and re-pasting. By doing so, it is possible to reuse the sandblast waste material, and it is also possible to avoid environmental problems due to the disposal of the sandblast waste material.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of a flow of collecting a rib forming material.

FIG. 2 is a schematic configuration diagram illustrating an example of a cyclone and a dust collecting device incorporated in a rib forming material collecting step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Communication pipe 12 Cyclone 13 Distributor 14 Duct 15 Dust collector 15a Filter 16 Blower 17 Grinding material tank 18 Injection nozzle 19 Valve 20 Valve 21 Dust tank

Claims (2)

[Claims] A rib forming material layer is formed by applying and drying a rib forming paste on a substrate, and a mask pattern having sandblast resistance is formed thereon, and a rib forming material layer on an exposed portion thereof is formed. In a method of forming a rib of a plasma display panel including a step of grinding by a sandblasting method using a sandblasting abrasive, after grinding the rib forming material layer by a sandblasting method using a sandblasting abrasive, the grinding mixed during sandblasting By removing the abrasive particles from the mixed powder by classifying the mixed powder of the abrasive particles and the grinding powder of the rib forming material, adjusting the excess and deficiency components and re-pasting, the rib material is recovered A rib material method for a plasma display panel, characterized in that it is reused. 2. The method for forming a rib of a plasma display panel according to claim 1, wherein the adjustment of the excess or deficiency component includes adjusting the frit component and the resin amount.