JP2001202875A - Method of forming rib of plasma display panel and rib formed by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a good shape of rib without lowering of cut ability when a rib of plasma display panel is formed by the sand blast machining method. SOLUTION: A density of grinder material in mixed air after blasting is set to 50-200 g/m3, and the maximum value in a collision speed of the mixed air to a substrate is set to the range of 45-70 m/s. As the amount and speed of the grinder material, which entrained in the air and blasted, is proper, a good shape if rib can always be formed without lowering of the grinder speed. The rib 3 can satisfy the condition of 0<= (WB-WT)<=40 μm, 0<=(WT-Wmin)<=20 μm. If the bottom width WB is larger by above 40 μm than the head width WT, the unevenness in wider skirt may be generated, also if the minimum width Wmin is smaller by above 20 μm than the head width WT, the rib is thin to weaken the strength.

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 PDP has a structure in which a pair of electrodes arranged regularly on two opposing glass substrates are provided, and a gas mainly composed of Ne, Xe or the like is sealed between the electrodes. Then, a voltage is applied between these electrodes,
By generating a discharge in a minute cell around the electrode, each cell emits light to perform display. In order to display information, regularly arranged cells are selectively caused to emit light. There are two types of PDPs, a direct current type (DC type) in which the electrodes are exposed to the discharge space, and an alternating current type (AC type) in which the electrodes are covered with an insulating layer. And a refresh driving method and a memory driving method.

FIG. 1 shows a configuration example of an AC type PDP. This figure shows the front plate and the back plate separated from each other. As shown in the figure, two glass substrates 1 and 2 are arranged in parallel and opposed to each other, and both become the back plate. The ribs 3 provided on the glass substrate 2 in parallel with each other are held at regular intervals. On the back side of the glass substrate 1 serving as a front plate, composite electrodes composed of a sustain electrode 4 which is a transparent electrode and a bus electrode 5 which is a metal electrode are formed in parallel with each other, and a dielectric layer 6 is covered thereover. The protective layer 7 (MgO layer) is further formed thereon. On the front side of the glass substrate 2 serving as the back plate, address electrodes 8 are formed between the ribs 3 so as to be orthogonal to the composite electrodes and are formed in parallel with each other. Are formed, and a phosphor layer 10 is provided so as to cover the wall surface of the rib 3 and the cell bottom surface. This AC type PDP is of a surface discharge type, and has a structure in which an AC voltage is applied between composite electrodes on the front panel to discharge. Then, the phosphor layer 10 emits light by the ultraviolet light generated by the discharge, so that an observer can visually recognize the light transmitted through the front plate.

Conventionally, the ribs on the back plate of such a PDP have been formed by overprinting by screen printing. However, recently, the ribs are often formed by a so-called sand blast method from the viewpoint of accuracy. When ribs are formed by this method, a low-melting glass powder, an inorganic powder such as a refractory filler is used as a main component or a component, and a rib paste obtained by adding an appropriate binder resin and a solvent thereto is applied to a substrate. After forming a rib material layer by drying and providing a photosensitive resin composition layer having sandblast resistance thereon, the rib material layer is patterned into a cell defining mask by a photolithography method. A procedure is employed in which unnecessary portions of the rib material layer are removed by injecting mixed air containing abrasives from an injection nozzle, and then a sandblast resistant mask is removed before firing. And, as the abrasive, glass beads,
Inorganic powders such as SiC, SiO ₂ , Al ₂ O ₃ and ZrO ₂ are used.

[0005]

In the above-described rib formation by the sand blast method, it is important to grind the ribs 3 as vertically as possible as shown in FIG. That is, in the shape in which the skirt is widened as shown in FIG. 2B, the processing unevenness of the rib 3 is apt to occur, and in the shape in which the side etch is excessively formed as shown in FIG. The line width of the portion is too small, and there is a possibility that the rib 3 falls down when the mask for sandblasting is peeled off. As described above, it is necessary to form a rib having a shape as close as possible to the vertical, but conventionally, it is difficult to always form a rib having a good shape because the injection condition of the abrasive is empirically determined. was there.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has been made to reduce the amount of abrasive in the injected mixed air so as to obtain a good rib shape without lowering the grinding speed. , And also the injection speed of the mixed air. By performing the sand blasting with the abrasive material jetting conditions set to be appropriate in this manner, a rib having a good shape can always be formed without reducing the grinding ability.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a rib material layer is formed on a substrate, a mask for sandblasting is formed on the rib material layer in a pattern, and then mixed air containing abrasives is jetted from above the mask. By removing unnecessary portions of the rib material layer, and then removing the anti-sandblast mask, a method of forming a rib of a PDP including a step of forming a rib having a desired pattern through a firing step is performed. Is set to a concentration of 50 to 200 g / m ³ .

[0008] The concentration of the abrasive in the mixed air is 200 g /
If it exceeds m ³ , the amount of the abrasive will be too large, and the abrasive will move laterally due to the collision of the abrasive itself, so that the side etch amount will increase in the grinding of the ribs. That is, the rib has a concave shape at the center. With such a shape, the strength of the rib is insufficient. Conversely, when the concentration of the abrasive in the mixed air is less than 50 g / m ³ , the amount of the abrasive is too small, and as a result, the grinding ability is too small and the grinding time is too long.

Further, in addition to defining the concentration of the abrasive in the mixed air as described above, it is desirable to set the maximum value of the collision speed of the mixed air to the substrate in the range of 45 to 70 m / s. If the collision speed of the mixed air with the substrate exceeds 70 m / s, the rib shape becomes good, but the underlying dielectric layer and electrode are easily damaged. Furthermore, the edge of the sandblast mask is easily peeled off, which causes rib defects. On the other hand, if the collision speed of the mixed air to the substrate is less than 45 m / s, the rib grinding ability is too small and the grinding time is too long.

As described above, by defining the concentration of the abrasive in the mixed air immediately after being injected from the injection nozzle and further defining the collision speed of the mixed air with the substrate, a rib having a good shape is formed. Speaking sizes, as shown in FIG. 3, the bottom width of the rib 3, W top width, the minimum rib width, respectively _B, W _T, When W _min, the shape before firing the next equation (1) And a rib 3 satisfying (2) is formed. _{0 ≦ (W B -W T)} ≦ 40μm ···· (1) 0 ≦ (W T -W min) ≦ 20μm ··· (2)

[0011] bottom width W _B is 40μm or more larger than the top width W _T, becomes so wide foot processing unevenness is likely to occur,
If the minimum rib width W _min is smaller than the top width W _T by 20 μm or more, the rib becomes too thin and the strength of the rib is weakened.

[0012]

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

(Electrode forming step) The planar size is 10
A glass substrate having a size of 00 × 600 mm and a thickness of 2.8 mm is prepared, and a large number of parallel striped electrodes are formed by screen printing on one surface of the glass substrate at intervals of 150 μm.

(Rib material layer forming step) A rib paste having the following composition A is coated on the entire surface of the glass substrate on the electrode side by a die coater, dried at 150 ° C. for 30 minutes and solidified to form a rib material layer. To form

—Composition A— 100 parts by weight of glass frit (main component: PbO, SiO ₂ (alkali-free), average particle size 3 μm) 7 parts by weight of Al ₂ O ₃ (pigment) 7 ZrO ₂ (aggregate) 7 Parts by weight ・ Ethyl cellulose (resin) 6 parts by weight ・ Terpineol (solvent) 25 parts by weight ・ Butyl carbitol (solvent) 10 parts by weight

(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 material layer.
Exposure and subsequent development are performed to form a patterned resist layer as a sandblast mask on the rib material layer. As the developing solution, a 0.2% aqueous solution of sodium carbonate is used. Note that the pattern of the resist layer of the present embodiment has a width of 50 μm.
m, the electrodes on the surface of the glass substrate are in parallel stripes with a distance of 10 μm.
It is arranged so as to be located approximately at the center between 0 μm.

(Sand blasting process) The substrate is moved on a number of transport rollers and is carried into the blasting chamber. Then, the abrasive is sprayed from a spray nozzle toward the rib material layer and the resist layer side of the workpiece having the rib material layer and the resist layer formed on the surface of the substrate, that is, the glass substrate. In this embodiment, the abrasive has an average particle size of 11.5.
μm alumina (Fujimi Incorporated “WA
# 1000 ”).

In the processing chamber, eight injection nozzles of a type which reciprocate in a direction orthogonal to the substrate transfer direction are provided. As each of the injection nozzles, a slit nozzle that injects the abrasive almost vertically from a slit of 150 mm × 0.5 mm is employed. The slit nozzle itself has a wider spray distribution than the conventional round nozzle (10 mmφ), but the driving speed of the spray nozzle is increased to further improve the processing uniformity.

In the processing chamber, a grinding material is sprayed together with the compressed air onto the glass substrate on the side of the resist layer and the rib material layer, and the rib material layer other than the rib material layer immediately below the resist layer is ground and removed. Is patterned. The rib patterned in this manner has a width of 50 μm, a height of 150 μm, and an interval between the ribs of 100 μm.
Specifically, when a grinding material is sprayed from the spray nozzle to the resist layer and the rib material layer side of the substrate in the blasting chamber, the rib material layer immediately below the resist layer is protected by the resist, so the grinding material is ground or engraved with the grinding material. However, all the rib material layers other than the rib material layer immediately below the resist layer are removed by grinding.

(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 lead glass of the low melting point 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.

The ribs are formed by the above steps. In this embodiment, a test was performed by injecting abrasives under various conditions and performing the above sandblasting.

First, as a first test, the collision speed of the mixed air with the substrate was set to 50 m / s, the concentration of the abrasive in the mixed air was changed, and the substrate was subjected to sandblasting, and the grinding speed and the side speed were measured. The etch was evaluated. The results are as shown in Table 1. As can be seen from Table 1, when the concentration of the abrasive in the mixed air exceeds 200 g / m ³ , although the grinding speed is good, the amount of side etching becomes larger than the allowable range. The concentration of the abrasive in the mixed air is 50 g / m ^3.
If it does not, the grinding speed has decreased.

[0023]

[Table 1]

In a second test, the concentration of the abrasive in the mixed air was adjusted to 100 g / m ³ , the sandblasting of the substrate was performed by changing the collision speed of the mixed air with the substrate, and the grinding speed and mask peeling were performed. Was evaluated. Table 2 shows the results. As can be seen from Table 2, when the collision speed of the mixed air with the substrate exceeded 70 m / s, the resist was peeled off. Further, the collision speed of the mixed air with the substrate is 45
When the speed was less than m / s, the grinding speed was reduced.

[0025]

[Table 2]

[0026]

As described above, according to the present invention,
When forming the ribs of the PDP by the sandblasting method, the concentration of the abrasive in the mixed air immediately after the injection is set to 50 to 2
Set 00g / m ^3, more by the maximum value of the impact velocity relative to the substrate of the mixed air is set to a range of 45~70m / s, the amount and speed of the grinding material to be injected is put in the air is appropriate Therefore, a rib having a good shape can always be formed without lowering the grinding speed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a plasma display panel in which a front plate and a back plate are separated from each other.

FIG. 2 is a cross-sectional view for explaining the shape of a rib.

FIG. 3 is an explanatory diagram for defining dimensions of each part of a rib.

[Explanation of symbols]

 1, 2 glass substrate 3 rib 4 sustain electrode 5 bus electrode 6 dielectric tank 7 protection tank 8 address electrode 9 dielectric tank 10 phosphor layer

Claims (3)

[Claims] After a rib material layer is formed on a substrate and a sandblast resistant mask is formed thereon in a pattern,
Unnecessary portions of the rib material layer are removed by injecting mixed air containing abrasives from above the mask, and then the sandblast resistant mask is removed, and then a firing process is performed to form a rib having a desired pattern. A method of forming a rib for a plasma display panel, comprising: setting a concentration of an abrasive in mixed air immediately after injection to 50 to 200 g / m ³ . 2. The method according to claim 1, wherein the maximum value of the collision velocity of the mixed air against the substrate is set in a range of 45 to 70 m / s. 3. A rib formed by the rib forming method according to claim 1 or 2, wherein a bottom width, a top width, and a width of the rib are determined.
Minimum rib width, respectively W _B, W _T, when the W _min,
A rib for a plasma display panel, wherein a shape before firing satisfies the following relational expressions (1) and (2). _{0 ≦ (W B -W T)} ≦ 40μm ···· (1) 0 ≦ (W T -W min) ≦ 20μm ··· (2)