KR20030017244A - Fabrication method of rolling mold for barrier rib in plasma display panel and method of forming barrier rib using the mold - Google Patents

Abstract

PURPOSE: A method for producing a soft rolling mold and a method for forming barrier ribs are provided to minimize the damage on barrier rib patterns by permitting the mold to be easily removed, while obtaining barrier ribs having uniform heights. CONSTITUTION: A method for producing a soft rolling mold for formation of barrier ribs of a plasma display panel, comprises a first step of depositing a photoresist on the surface of a rear surface substrate(30); a second step of forming a basic mold frame by forming photoresist patterns through the use of a photomask where barrier rib patterns are formed; a third step of injecting a rubber material in a solution state into the basic mold frame; a fourth step of solidifying the rubber material; a fifth step of obtaining a soft mold(32) by separating the solidified rubber material from the basic mold frame; and a sixth step of attaching the soft mold to a hard cylinder in such a manner that the soft mold covers the outer surface of the hard cylinder.

Description

Fabrication method for forming barrier ribs of plasma display panel and method for forming barrier ribs using the same {{Fabrication method of rolling mold for barrier rib in plasma display panel and method of forming barrier rib using the mold}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel (PDP) manufacturing technology, and more particularly, to a method of manufacturing a soft rolling mold for forming a barrier rib of a PDP and a method of forming a partition using the same.

The plasma display panel (PDP) is a display element for displaying an image by using a plasma generated during gas discharge, and is also called a gas discharge display element. The PDP fills discharge gas such as Ne and Xe between the upper plate and the lower plate, and the vacuum ultraviolet rays generated through the gas discharge excite the red (R), green (G), and blue (B) phosphors to generate visible light.

PDP is divided into direct current (DC) type and alternating current (AC) type. In the DC type, the electrode used to apply an external voltage to form a plasma is directly exposed to the plasma so that the conduction current is directly transmitted through the electrode. In such a way as to flow, the structure has a relatively simple advantage, but the electrode is exposed to the discharge space has the disadvantage that it must have an external resistance for limiting the current. AC type is a method that the electrode is covered with a dielectric so that it is not directly exposed so that the displacement current flows, and the current is limited by covering the electrode with a dielectric, which protects the electrode from ion shock during discharge, resulting in longer life than DC type. . AC type is divided into counter discharge type and surface discharge type again according to the electrode structure of discharge cell. In the opposite discharge type, there is a problem that the phosphor is shortened due to phosphor deterioration due to ion shock, whereas the surface discharge type discharges the phosphor. Overcoming the problem of the opposite structure by minimizing phosphor degradation by gathering on the opposite side, most PDPs adopt this method.

On the other hand, among various flat panel displays, PDP is easy to implement a thin screen and a large screen, and thus, the field of use of the PDP is increasing from the current bulletin board of the stock exchange, the video conferencing display, and the large wall-mounted TV.

1 is a cross-sectional view of a surface discharge type AC PDP.

Referring to FIG. 1, in the surface discharge type AC PDP, a back substrate 10, an address electrode 11, a white dielectric 12, a partition 13, and the like form a back substrate, the front substrate 14, and the transparent electrode 15. ), The bus electrode 16, the transparent dielectric 17, the dielectric protective film 18, a black stripe (not shown), and the like form a front plate. In addition, phosphors R, G, and B 19 for realizing color in the PDP are disposed on the front plate in the case of a transmissive type and between partition walls 13 of the back plate in the case of a reflective type.

Among these, the partition wall has a three-dimensional structure with a line width of about 50 to 80 µm, which makes the formation process difficult. Currently, PDP bulkhead formation process includes screen printing method, sand blast method, photolithography, press method, and LTCC-M (Low Temperature Co-fired). Ceramic on Metal) and the like are known.

Screen printing is a method of repeating a desired pattern printing and drying process several times using a screen mask. Since the screen printing method requires repeated printing several times until the desired barrier height is obtained, the barrier is inclined, the instability of the discharge characteristics due to the height deviation of the barrier, the uniformity of phosphor formation, and the screen mask mesh ) Markings are pointed out as a problem, and yields are expected to be low due to poor reproducibility, and due to limitations of screen masks, it is difficult to produce high-definition patterns. In other words, when forming a partition by the conventional printing method, as described above, the printing and drying process must be repeated several times until the desired height is reached, and this process requires a lot of time, not only decreases productivity. As a result, the tension of the screen mask, the characteristics of the paste may change with time, and there is a problem in that the printing is not directly performed at the initial position even after the alignment. For reference, the height of the barrier rib formed in one printing is about 15 to 25 µm, and the height of the desired barrier rib is usually 100 to 200 µm. In addition, the flatness of the partition wall during printing may be deteriorated due to the pattern stains generated during the mask fabrication process, which not only affects the formation of the phosphor but also causes an unstable discharge during image formation. In addition, the width of the printable pattern is limited due to the mask pattern width and the limitation of the screen mesh, and it is pointed out as an obstacle in producing a high-definition and high-quality panel.

In the sand blasting method, after the barrier paste is coated and dried to a thickness of 300 to 400 μm, the dry film resist (DFR) having a sanding resistance is laminated and patterned through an exposure and development process. Using this pattern as a mask, the partition paste is scraped off with fine abrasive grains. This sandblasting method has the advantage that it is possible to form a high-definition bulkhead compared to the printing method, but the process is complicated and material loss, and the separation of the powder mixture produced during the sandblasting process is not easy and environmentally friendly because it is a pollution material There is a problem. Above all, it is pointed out that the cracks in the partition wall during the subsequent firing process are large because the physical impact caused on the glass substrate during the sandblasting process is large.

Photolithography is a process of applying and drying the photosensitive partition wall paste, exposing with a photomask, and then selectively dissolving and removing the non-exposed portion of the paste with a developer. While the photolithography method has an advantage in that precise dimension adjustment is possible, the loss of the paste is large and it is difficult to form a barrier rib having a height of 100 μm or more because it is difficult to photosensitize to the lower portion of the photosensitive barrier paste.

In the mold method, after the green tape is attached on the substrate, the plate-shaped metal mold having the partition pattern engraved thereon is aligned on the green tape, subjected to pressure molding under high temperature conditions, and then the plate-shaped metal mold is placed in the vertical direction. It is a process of separating and forming a partition. This mold method has the advantage that the process is very simple and the material utilization is high, while the height uniformity of the obtained partition wall is inferior, and the glass substrate is broken due to the pressure applied to the mold of a large area. Since the contact area between the metal mold and the green tape is large, separation (demolding) is difficult.

Low Temperature Co-fired Ceramic on Metal (LTCC-M) method attaches a green tape on a metal substrate (e.g., Ti), forms an address electrode and a dielectric layer on the green tape, and then forms an embossing mold, which is a plate-shaped metal mold. It is a process of forming a partition by press molding with an embossing mold. The LTCC-M method simplifies the process, saves equipment and materials costs, and eliminates the shrinkage of the bulkhead pattern during simultaneous firing, which solves the alignment problem. In addition, the weight of the back substrate is reduced by replacing the heavy glass substrate with a thin metal plate. There is an advantage that can be reduced, and by using a metal substrate with high thermal conductivity there is an advantage of excellent heat dissipation characteristics of the back substrate. However, in order to be applied to mass production of PDP, technical matters such as securing ease of demoulding after pressure forming, suppressing warp generated during simultaneous firing, and preventing bending of back substrate during pressure forming should be solved.

On the other hand, a rolling mold method (rolling mold method) has been proposed in order to reduce the damage of the glass substrate due to the high pressure during the press molding, which is a disadvantage of the mold method. The rolling mold method is a process of pressing a barrier rib paste applied on a substrate by rolling a metal cylinder (rolling mold) in which a stripe-shaped barrier rib is engraved on an outer circumferential surface thereof. Therefore, the glass substrate has a small pressure compared to the conventional mold method to prevent damage to the glass substrate, there is an advantage that does not require a cumbersome demolding process. However, it is difficult to manufacture metal molds because it is not easy to process metals, and thus, there is a disadvantage in that mold manufacturing costs are high.As the rolling progresses during molding, the paste adheres to the mold, so that a uniform partition pattern of high-definition can be obtained in a continuous process. There was a hard problem to get.

The present invention has been proposed to solve the above problems of the prior art, for preventing the formation or damage of glass substrates, and for forming partition walls of the plasma display panel, which can obtain a high-definition uniform partition even in a continuous process. It is an object of the present invention to provide a soft rolling mold production method and a partition wall formation method using the same.

1 is a cross-sectional view of a surface discharge type AC PDP.

2a to 2e is a soft rolling mold manufacturing process diagram for forming the partition wall of the PDP according to an embodiment of the present invention.

3A to 3C are diagrams illustrating a process for forming barrier ribs of a PDP using the soft rolling mold of the present invention.

* Explanation of symbols for main parts of the drawings

30: back substrate

31: bulkhead paste

32: soft rolling mold

According to an aspect of the present invention for achieving the above technical problem, the step of applying a photoresist on a substrate for a base mold; Forming a basic mold by forming a photoresist pattern using a photomask on which a partition pattern is drawn; Injecting a rubber raw material in a liquid state into the base mold; Curing the rubber raw material; Separating the cured rubber stock from the base mold to obtain a soft mold; And attaching the soft mold to surround the outer circumferential surface of the hard cylinder, thereby providing a soft rolling mold for forming a partition wall of the plasma display panel.

According to another aspect of the present invention, in the method for forming a partition wall of a plasma display panel using a soft rolling mold manufactured according to the method for fabricating a partition wall forming soft rolling mold of the plasma display panel, a barrier material film is formed on a substrate. Forming; Aligning the soft rolling mold having the partition pattern engraved on the barrier material layer; Forming a barrier rib pattern while rolling the soft rolling mold; And firing the partition pattern.

The rolling mold for forming a partition wall of the PDP according to the prior art was manufactured using a metal material. Rolling mold made of metal is difficult to manufacture, and it is difficult to produce high-definition bulkhead pattern on the outer circumferential surface as well as the surface tension and frictional force are not easy to release, so it is difficult to obtain a high-definition uniform bulkhead. there was. In the present invention, using a rubber material having elasticity, such as silicone rubber, urethane rubber, etc. to produce a high-precision soft mold that is easy to bend, the soft mold is bonded to the outer cylinder surface of the metal material A soft rolling mold is produced, and a partition is formed by the rolling mold method using the same. As described above, in the case of forming the partition wall using the soft rolling mold, since the surface tension and the frictional force of the soft rolling mold are small, it is not only easy to release the mold from the press-molded partition layer, but also it is possible to form a highly uniform partition wall.

Hereinafter, preferred embodiments of the present invention will be introduced in order to enable those skilled in the art to more easily carry out the present invention.

2a to 2e is a soft rolling mold manufacturing process according to an embodiment of the present invention, will be described below with reference to this.

First, as shown in FIG. 2A, an adhesive layer 21 is deposited on a metal substrate (copper, nickel, etc.) 20 or a glass substrate using plasma enhanced chemical vapor deposition (PECVD) equipment. At this time, it is preferable to use amorphous silicon as the adhesive layer 21, and it is deposited by 0.1 micrometer-0.2 micrometer thickness.

Next, as shown in Fig. 2B, a photoresist (e.g., SU 8 of microchem), which is easy to form a thick film of 300 µm or more, is spin-coated (900 rpm, 30 sec) and dried (90 DEG C / 20 min). .

Subsequently, an exposure (360-420 nm exposure source, 600-1000 mJ / cm ² exposure energy) process is performed using a photomask on which a partition pattern is drawn as shown in FIG. 2C, and development is performed to prepare a basic mold. .

Subsequently, the liquid RTV transparent silicone rubber raw material (for example, silicone resin solution: hardener = 5 to 15: 1) or urethane rubber raw material is injected into the basic mold in a vacuum molding machine as shown in FIG. After removal, the oven is cured at about 80 ° C. for about 5 minutes. Then, the liquid RTV transparent silicone rubber cured from the base mold is gradually separated from the edge portion to obtain the soft mold 23.

Next, as illustrated in FIG. 2E, the soft mold 23 is bonded to surround the metal cylinder 24 to form the soft rolling mold 25.

As described above, in the present invention, a soft rolling mold for forming partition walls of a PDP is manufactured by using a silicone rubber or urethane rubber having flexural elasticity. On the other hand, in the present invention, amorphous silicon is used as the adhesive layer in fabricating the basic mold using the photoresist. Amorphous silicon is excellent in adhesion with a photoresist as well as a metal substrate or a glass substrate can ensure a stable mold manufacturing process. In addition, when manufacturing a mold through the above process, it is possible to easily implement a variety of cell structure (b partition structure) only by changing the design of the photomask.

3A to 3C are diagrams illustrating a process for forming barrier ribs of a PDP using the soft rolling mold of the present invention.

In the process of forming the partition wall of the PDP using the soft rolling mold according to the present embodiment, first, as shown in FIG. 3A, the partition wall paste 31 is applied on the back substrate 30 to a thickness of 200 to 300 μm.

Next, as shown in FIG. 3B, the partition pattern is formed using the soft rolling mold 32. At this time, it rolls, applying an appropriate pressure to the soft rolling mold 32, maintaining the board | substrate temperature at the temperature of 30-80 degreeC.

FIG. 3C shows that the barrier rib pattern is formed using the soft rolling mold 32, and then a baking process is performed at a temperature of 500 to 580 ° C. to burn and remove the organic component in the barrier paste 31, leaving only the inorganic barrier material. The state which obtained the partition 31a of 110-130 micrometers in height is shown.

In the case of performing the above process, the process is simple and similar to the case of using a conventional metal rolling mold, there is an advantage that can prevent damage to the substrate, because it uses a rolling mold of elastic material rather than metal A uniform partition pattern can be obtained.

As a result of the experiment, when the partition wall is formed by using a conventional metal rolling mold, some partition wall patterns are degraded due to the friction force between the partition paste and the metal rolling mold, and the height of the partition walls is averaged. While a deviation of about 5% relative to the height was shown, the partition obtained according to the present invention exhibited a deviation within 0.5% of the average height. On the other hand, in the case of using a conventional metal rolling mold, it is difficult to form a uniform partition wall in a continuous process because the partition paste is stuck between the partition cell structures of the rolling mold, but it is used as a material of the soft rolling mold in the present invention. Since silicone rubber and urethane rubber have smaller surface tension and friction than metal, it is possible to reduce the sticking of paste in the rolling process to form uniform barrier ribs in a continuous process.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be apparent to those of ordinary knowledge.

As described above, the present invention has the effect of ensuring a stable mold manufacturing process, can prevent the bending or damage of the glass substrate can increase the yield of PDP, and the mold wall is easy to demould the mold generated in the demolding process Damage to the pattern can be minimized, and partition walls having a uniform height can be obtained, thereby securing the manufacturing technology of the high-definition PDP. In addition, the present invention has an effect that can easily implement a variety of partition pattern through the production of a basic mold using a photoresist.

Claims (8)

Applying a photoresist on the base mold substrate; Forming a basic mold by forming a photoresist pattern using a photomask on which a partition pattern is drawn; Injecting a rubber raw material in a liquid state into the base mold; Curing the rubber raw material; Separating the cured rubber stock from the base mold to obtain a soft mold; And Bonding the soft mold to surround the outer circumferential surface of the hard cylinder Soft rolling mold manufacturing method for forming a partition wall of the plasma display panel comprising a. The method of claim 1, And depositing amorphous silicon as an adhesive layer on the surface of the substrate for the basic mold mold. The method according to claim 1 or 2, The rubber raw material is a urethane rubber raw material, the soft rolling mold manufacturing method for forming a partition wall of the plasma display panel. The method according to claim 1 or 2, The rubber raw material is a soft rolling mold for forming a partition wall of the plasma display panel, characterized in that the silicon rubber raw material. The method according to claim 1 or 2, The base mold mold substrate is a metal substrate or a glass substrate, characterized in that the mold forming method for forming the partition wall of the plasma display panel. The method of claim 4, wherein The silicon rubber is a liquid crystal RTV transparent silicone rubber, characterized in that the partition wall forming mold manufacturing method of the plasma display panel. A method of forming a partition wall of a plasma display panel using a soft rolling mold manufactured according to the method of manufacturing a partition wall forming soft rolling mold of claim 1, Forming a barrier material film on the substrate; Aligning the soft rolling mold having the partition pattern engraved on the barrier material layer; Forming a barrier rib pattern while rolling the soft rolling mold; And Firing the partition pattern A partition wall forming method of a plasma display panel comprising a. The method of claim 7, wherein In the forming of the barrier rib pattern, And rolling the soft rolling mold while maintaining the substrate temperature at 30 to 80 ° C.