KR20010003713A - Plasma display panel - Google Patents

Abstract

PURPOSE: A plasma display panel is provided to improve a contrast and a light emitting efficiency, and to generate an amount of light emitted from sub-cells corresponding to red, green and blue in balance. CONSTITUTION: A plasma display panel has barrier ribs(106,108) enclosed with respective sub-cells(102) and pixel cells(104). Each of a red(R), green(G) and blue(B) sub-cells is divided by a sub-barrier rib(106) between the sub-cells(102). One pixel cell comprises the red(R), green(G) and blue(B) sub-cells. A main barrier rib(108) divides the pixel cell(104) and the adjacent pixel cell(104). A width of the sub barrier rib(106) between the sub cells(102) is narrower than the main barrier rib(108) between the pixel cells(104). A discharge space of the red sub-cell(R) is larger than a discharge space of the blue sub-cell(B). The discharge space of the blue sub-cell(B) is larger than a discharge space of the green sub-cell(G). The size of respective sub-cells is different because each of sub-cells has a different light emitting efficiency. The light emitting efficiency of the red(R) sub-cell is most low among the three sub-cells, and so the discharge space of the red(R) sub-cell is most large among the three sub-cells. Relatively, The light emitting efficiency of the green sub-cell(G) is most high among the three sub-cells, and so the discharge space of the green sub-cell(G) is most small among the three sub-cells. Therefore, light is emitted from respective the sub-cells in balance.

Description

Plasma Display Panel

The present invention relates to a plasma display, and more particularly to a plasma display panel with improved discharge efficiency and contrast.

The plasma display is a display device in which ultraviolet light generated by gas discharge acts on a phosphor to generate visible light from the phosphor. The plasma display is thinner and lighter than the Cathode Ray Tube (CRT), which has been the mainstay of the display device, and has the advantages of easy to realize a high-definition large screen and a wide viewing angle. have. The plasma display panel is composed of pixel cells arranged in a matrix, and is classified into a direct current (DC) driving method and an alternating current (AC) driving method according to the driving method thereof.

1 is a diagram illustrating a cell structure of a plasma display panel of a general AC driving method. Referring to FIG. 1, first, a pair of bus electrodes 30 and a pair of transparent electrodes (ITO electrodes) 26 are arranged side by side on the bottom surface of the upper glass substrate 20 to achieve surface discharge. The dielectric layer 34 for accumulating wall charges during the address discharge surrounds the bus electrode 30 pair and the transparent electrode 26 pair and is applied to the entire bottom surface of the upper glass substrate 20. The MgO passivation layer 36 coated on the entire dielectric layer 34 extends the lifetime of the pixel cell and increases the emission efficiency of secondary electrons. On the lower glass substrate 22, an address electrode 28 for address discharge intersects the bus electrode 30 at right angles to each other. The dielectric thick film 24, which performs the same role as the dielectric layer 34, is coated on the lower glass substrate 22 surrounding the address electrode 28. A partition wall 32 is formed on the thick dielectric film 24, and a phosphor 38 is applied on the surface of the partition wall 32 and the thick dielectric film 24 to be excited by ultraviolet rays during discharge to emit visible light. The partition 32 forms a coating surface of the phosphor 38 and forms a discharge region 40 together with the upper and lower glass substrates 20 and 22. The discharge region 40 is filled with a mixed gas of He + Xe or Ne + Xe.

A brief description will be given of the light emission process. In the state where wall charges are accumulated in the dielectric layer 34 due to the address discharge between the bus electrode 30 and the address electrode 28, the bus electrode 30 is disposed in the discharge region 40. Ultraviolet rays are emitted as the surface discharge of the liver occurs. The emitted ultraviolet rays excite the phosphor 38 to generate visible light of any one of red, green, and blue.

The partition wall 32 is made of glass-ceramics material and is designed to have a width of about 100 μm and a height of about 200 μm. The partition wall 32 is required to have a large aspect ratio (a ratio of height to width) in order to obtain a satisfactory aperture ratio. In particular, when the partition wall of the plasma display panel has a large aspect ratio, the phosphor coating area and the discharge space are increased accordingly, thereby improving the discharge efficiency and luminance.

Screen printing method, sand blasting method, mold method and the like have been proposed as a method of manufacturing the partition wall, but many problems have been pointed out in each method. In the screen printing method, a printing and drying process is performed several times to make a structure having a required height, and then fired to form a partition wall. This manufacturing method takes a lot of manufacturing time due to the repetition of the process, it is difficult to form a high-definition partition wall having a large aspect ratio due to the position of the screen and the substrate is shifted under the repeated operation. In the sandblasting method, a partition wall material is formed to a desired thickness, and then a photosensitive resin pattern is formed thereon to remove unnecessary portions by the sandblasting method to form partition walls. This manufacturing method is not only a waste of the material removed by the abrasive (sand particles) and the manufacturing cost is large, but also a physical impact on the glass substrate by the abrasive has a problem that causes damage to the substrate. In the mold method, the partition wall material is formed and then stamped with a mold to form the partition wall. In the mold method, it is difficult to control the pressure between the mold and the semisolidified partition film or the partition wall paste, and the separation between the mold and the partition wall is difficult, which makes it difficult to manufacture high-definition partition walls. All of the above-mentioned barrier rib manufacturing methods have problems such as process complexity and precise process control, and thus are not established as preferable mass production processes. In addition to these methods, a method of manufacturing a partition wall having a large aspect ratio has been proposed, such as LIGA (Lithography + Electroplating + Molding) method, anisotropic etching method of silicon, etching method of photosensitive glass substrate, and the like. The LIGA method is a method of irradiating X-rays generated from an accelerator to a resin material to change the properties of the portions irradiated with X-rays and then etching them to remove portions irradiated with X-rays. The LIGA method has the disadvantage of requiring expensive equipment because it must generate X-rays. Anisotropic etching of silicon is a method of forming a structure using the vertical preferential etching of the Si (110) substrate. This method has a disadvantage in that it is difficult to form barrier ribs evenly over a large area and an expensive silicon single crystal must be used. On the other hand, the etching method of the photosensitive glass substrate has the advantage that it is relatively easy to manufacture a partition having a large aspect ratio on a large area in a low cost process.

The etching method of a photosensitive glass substrate is divided into the etching method of a positive photosensitive glass substrate, and the etching method of a negative photosensitive glass substrate. Looking at the etching method of the positive photosensitive glass substrate, as shown in Figures 2a to 2d, the partition wall is formed by the procedure of forming the mask pattern, exposure, heat treatment, wet etching. First, the photosensitive glass substrate 60 as shown in FIG. 2A has a composition in which SiO ₂ , Li ₂ O, CeO ₂ and Al ₂ O ₃ as its main components and Au, Ag, Cu, etc. as a photosensitive metal are added in small amounts. Therefore, the photosensitive property is obtained by the composition to which other oxides are added. After the mask pattern 62 is formed on the photosensitive glass substrate 60 as illustrated in FIG. 2B, ultraviolet rays are exposed to light by a light source generating ultraviolet rays having a predetermined wavelength. At this time, when the photosensitive glass substrate 60 having a thickness of 1 mm is exposed, the energy of ultraviolet rays (based on 310 nm) is approximately 2 J / cm 2. In the exposed portion 64 of the photosensitive glass substrate 60 exposed for a predetermined time, electrons are emitted in the photosensitive glass substrate 60 as trivalent Ce ions are changed to tetravalent Ce ions. After exposure, the mask pattern 62 on the photosensitive glass substrate 60 is removed and the photosensitive glass substrate 60 is heat-treated to a predetermined temperature. In FIG. 2C, the electrons emitted by the exposure react with the photosensitive metal ions in the exposed portion 64 of the photosensitive glass substrate 60 to deposit metal elements. In such a state that the metal element is deposited, the photosensitive glass substrate 60 is heat-treated at a higher temperature in the heat treatment process of FIG. 2C. Then, the exposed portion 64 of the photosensitive glass substrate 60 forms a crystal phase such as SiO ₂ , Li ₂ O, etc. around the metal using the metal as a nucleus. Finally, when the heat-treated photosensitive glass substrate 60 is precipitated and wet etched in an aqueous solution containing hydrofluoric acid (HF) for a predetermined time, the exposed portion 64 in which the crystal phase is precipitated is dissolved and removed according to the degree of crystal phase precipitation. . As described above, in the etching method of the positive photosensitive glass substrate, the partition portion is formed by first removing the exposed portion 64 by using the etching rate difference between the exposed portion 64 and the unexposed portion 66 where the crystal phase is deposited.

The production of the partition wall using the etching method of the negative photosensitive glass substrate is performed in the same manner as the etching method of the positive photosensitive glass substrate, in order of forming a mask pattern, exposing, heat treatment and wet etching. However, in the etching method of the negative photosensitive glass substrate, the heat treatment temperature during the heat treatment is higher than that of the positive photosensitive glass substrate. In addition, in contrast to the etching method of the positive photosensitive glass substrate, the unexposed portions are removed in the etching step and the exposed portions remain to form partition walls. The etching method of the negative photosensitive glass substrate has an advantage that the partition having a large aspect ratio can be precisely formed as compared with the etching method of the positive photosensitive glass substrate.

Most of the partitions used in the plasma display panel have a stripe-shaped partition structure as shown in FIG. 1. 3 is a plan view illustrating a barrier rib structure having a stripe shape. On this stripe, there are no partitions for ensuring distinction between adjacent pixel cells 104 or subcells 102 on the same line. Thus, the ultraviolet light generated in the plasma may affect other phosphors on the same line, and the light generated in the phosphor may come out in an undesired direction. As a result, crosstalk between adjacent pixel cells 104 or subcells 102 is severe and the contrast is lowered. In order to solve this problem, a separate black mattress layer is formed on the upper glass substrate. The black mattress layer blocks the light of the generated visible light and thus may adversely affect the luminance. In addition, since the phosphor is formed only on the side of the barrier rib 100 on the stripe and on the lower plate, there is a problem in that the discharge area and the brightness of the phosphor are reduced, so that the discharge efficiency is low.

On the other hand, each phosphor that generates visible light of red (R), green (G), and blue (B) has a different luminous efficiency of visible light due to ultraviolet rays. In the conventional structure as shown in FIG. 3, since the discharge spaces of each of the subcells 102 generating one of the visible light of red (R), green (G), and blue (B) are all the same size, There is also a problem that it is not easy to adjust the amount of light generated in each subcell 102 to be uniform.

Accordingly, an object of the present invention is to provide a plasma display panel with improved contrast and discharge efficiency.

Another object of the present invention is to provide a plasma display panel in which the amount of light is balanced from the subcells corresponding to each of red, green, and blue.

1 is a perspective view schematically showing a cell structure of a general AC-driven plasma display panel.

2A to 2D are vertical cross-sectional views showing stepwise a method for producing a partition wall using positive photosensitive glass;

3 is a plan view showing a conventional barrier rib structure.

4 is a perspective view showing a partition structure according to an embodiment of the present invention.

5A to 5D are diagrams illustrating a barrier rib manufacturing method using an etching method of a positive photosensitive glass substrate according to an embodiment of the present invention, and a horizontal cross-sectional structure of the manufactured barrier rib.

6A to 6D are diagrams illustrating a barrier rib manufacturing method using an etching method of a negative photosensitive glass substrate and a horizontal cross-sectional structure of the manufactured barrier rib according to another embodiment of the present invention.

7 is a diagram illustrating a partition structure in which the subcells have the same size and the partition widths all have the same size.

<Description of the code | symbol about the principal part of drawing>

20: upper glass substrate 22: lower glass substrate

24 dielectric thick film 26 transparent electrode (ITO electrode)

28: address electrode 30: bus electrode

32,100: partition 34: dielectric layer

36: MgO protective film 38: phosphor

40: discharge area 60,140,180: photosensitive glass substrate

62,142,182: mask pattern 64,144,184: exposed portion

66,146,186: Unexposed part 102,202: Subcell

104,204 pixel cells 106,206 sub-barrier

108,208: Main bulkhead

In order to achieve the above objects, the plasma display panel according to the present invention has a main partition wall for distinguishing pixel cells including subcells corresponding to each of red, green, and blue, and a subcell having a width smaller than that of the main partition wall. It is provided with a sub-barrier for separating them.

Other objects and features of the present invention in addition to the above objects will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 4 to 6D.

4 is a perspective view illustrating a barrier rib structure of a plasma display panel according to an exemplary embodiment of the present invention. Referring to FIG. 4, the plasma display panel according to the present invention includes grid partitions 106 and 108 that surround the subcells 102 and the pixel cells 104 in all directions. The subcells 102 of red (R), green (G), and blue (B) are distinguished by the sub barrier ribs 106 between the subcells 102. One pixel cell 104 including the red (R), green (G), and blue (B) subcells 102 is distinguished from the adjacent pixel cells 108 by the main partition 108. The width of the sub barrier rib 106 between the subcells 102 is relatively narrow compared to the width of the main barrier rib 108 between the pixel cells 108. As for the size of the discharge space of the subcell 102, the discharge space of the red (R) subcell is the largest, the discharge space of the blue (R) subcell is the next largest, and the discharge space of the green (G) subcell is Smallest

5A to 5D illustrate a method of manufacturing a partition wall by using an etching method of a positive photosensitive glass substrate according to an exemplary embodiment of the present invention. 5A and 5B, a mask pattern 142 is formed on the photosensitive glass substrate 140 and exposed to ultraviolet rays. The photosensitive glass substrate 140 from which the post-exposure mask pattern 142 is removed is heat-treated at a predetermined temperature in the process of FIG. 5C. In the heat treatment process, a crystal phase is deposited on the exposed portion 144 of the photosensitive glass substrate. Finally, the exposed portion 144 where the crystal phase is deposited is removed by wet etching the heat-treated photosensitive glass substrate. The removed exposure portion 144 forms a discharge region of the subcell 102 of the plasma display panel as shown in FIG. 5D, and the unexposed portion 146 of FIG. 106, 108). The barrier rib structure shown in FIG. 4 may be easily implemented by forming the mask pattern 142 having the same horizontal cross-sectional structure on the photosensitive glass substrate in the process of FIG. 5B.

6A to 6D illustrate a method of manufacturing a partition wall using an etching method of a negative photosensitive glass substrate according to another exemplary embodiment of the present invention. Referring to FIG. 6A, first, a photosensitive glass substrate 180 including SiO ₂ , Li ₂ O, CeO ₂ , Al ₂ O _3, and a small amount of Au, Ag, Cu, or the like as a photosensitive metal is provided. Then, as shown in FIG. 6B, the mask pattern 182 is formed and then exposed by ultraviolet rays having a predetermined wavelength. In this case, when the photosensitive glass substrate having a thickness of 1 mm is exposed, the energy of ultraviolet ray (based on 310 nm) is about 0.3 to 1 J / cm 2, which is lower than that of the manufacturing process using the etching method of the positive photosensitive glass substrate. The exposed photosensitive glass substrate 180 is heat-treated in the process of FIG. 6C after the mask pattern 182 is removed. The heat treatment temperature at this time is heat-treated at a temperature of 600 ~ 650 ℃ higher than in the case of the manufacturing process using the etching method of the positive photosensitive glass substrate. By the heat treatment process, the exposed portion 184 and the unexposed portion 186 of the photosensitive glass substrate are systematically different from each other. In the heat treatment process of FIG. 6C, the unexposed portion 186 of the photosensitive glass substrate has an amorphous structure in which excessive defects exist, and the exposed portion 184 has a metal as a nucleus, such as SiO ₂ , Li ₂ O, or the like. As the crystal phase forms, it has a dense structure. The photosensitive glass substrate exhibiting such a partial structural difference is precipitated in an aqueous solution containing hydrofluoric acid (HF) for a predetermined time and wet-etched as a final process. Then, the unexposed portion 186 of the photosensitive glass substrate is easily dissolved since the non-exposed portion 186 has an amorphous structure with many defects to facilitate penetration of the hydrofluoric acid solution. Accordingly, the unexposed portion 186 is etched and removed faster than the exposed portion 184 having a dense structure. As a result, in the etching method of the positive photosensitive glass substrate, the exposed portion of the photosensitive glass substrate is etched and removed, whereas in the etching method of the negative photosensitive glass substrate, the unexposed portion having an amorphous structure with many defects is etched and removed. The unexposed portion 186 thus removed forms a discharge region of the subcell 102 of the plasma display panel as shown in FIG. 6D, and the unexposed portion 184 of FIG. 6C is the partition wall of FIG. 6D ( 106, 108). The barrier rib structure shown in FIG. 4 may be easily implemented by forming the mask pattern 182 having the same horizontal cross-sectional structure on the photosensitive glass substrate in the process of FIG. 6B.

In the manufacturing process of the partition wall, in order to solve the problem that the glass is broken by the thermal expansion that may occur in the subsequent bonding process, if necessary, by crystallizing the partition wall by heat treatment, the thermal expansion coefficient of the partition wall is 80X10 ^-7 / K to 90X10 It is preferable to set it as a value between ^-7 / K. To this end, in the case of using the etching method of the positive photosensitive glass substrate, it is possible to take a method of crystallization by heat treatment after exposure again. In addition, when the etching method of the negative photosensitive glass substrate is used, crystallization is performed on the formed partition wall itself, so that the coefficient of thermal expansion can be adjusted by changing the heat treatment time in the heat treatment process of FIG. 6C.

In the plasma display panel according to the present invention, instead of using a conventional black mattress layer to improve contrast, a method of blackening partition walls is used. The blackening process of a partition means the process which contains the substance which absorbs the visible light of all wavelengths in a partition. In the case of fabrication of the partition wall using the etching method of the positive photosensitive glass substrate, when the partition wall is manufactured by the process of FIGS. The blackening of a partition is possible by the metal particle and crystal grain formed by heat processing. In this case, there is no need to use a separate black mattress to improve the contrast. In addition, in the case of partition wall manufacture using the etching method of a negative photosensitive glass substrate, the translucent partition wall is formed by the process of FIGS. 6A-6D. In this case, it is possible to apply the black mattress paste to the surface layer of the partition wall (for example, dipping) to fire or to deposit the structure in which the partition wall is formed in the black mattress solution to blacken the partition wall. The blackened partition wall is bonded to the lower glass substrate by using a grasp, the phosphor is coated on the lower glass substrate and the partition wall surface, and then the upper glass substrate is bonded and the discharge gas is injected to complete the plasma display panel.

As shown in FIG. 4, the sub barrier ribs 106 and the main barrier ribs 108 prevent optical crosstalk between the sub cells 102 and the pixel cells 104, respectively, and are applied to the respective sub cells 102. The application area of the phosphor is expanded. The width of the sub barrier rib 106 is narrower than the width of the main barrier 108 to maximize the discharge space of the subcells 102. The main bulkhead 108 thicker than the sub bulkhead 106 can improve the contrast. As shown in FIG. 7, if the width of the sub barrier rib 206 is formed to be the same thickness as the width of the main barrier rib 208, the discharge space of the sub cells 202 may be reduced to reduce the discharge efficiency. do. As shown in FIG. 4, the sub-cells 102 of red (R), green (G), and blue (B) have a different size of discharge space for each color, so that light is balanced for each subcell 102. Release is achieved. That is, the red, green, and blue phosphors applied to the application surface of the subcell 102 have different light emission efficiencies of generating light by ultraviolet rays. R) Light is balanced from each subcell 102 by making the discharge space of the subcell the widest and the narrowest the discharge space of the green (G) subcell coated with the green phosphor having the highest luminous efficiency of visible light. It can be generated as an enemy. As shown in FIG. 7, when the subcells 202 of red (R), green (G), and blue (B) are all the same size, balanced mixing of red, green, and blue light is not performed. This can cause problems in color implementation.

When the partition structure shown in FIG. 4 is applied to the AC drive type plasma display panel, when the height of the partitions 106 and 108 is 100 to 500 µm, the width of the sub partition 106 may be set to about 20 to 50 µm. At this time, the width of the main partition 108 may be set to about 70 ~ 200㎛ in the case of a 40-inch plasma display panel. If a new type of plasma display panel having a higher height of the barrier ribs 106 and 108 is developed, the width of the barrier ribs 106 and 108 can be modified. 106) may be set to a value between 50 and 150 µm.

As described above, the plasma display panel according to the present invention includes a grid having a grid structure that separates the subcells and the pixel cells, thereby improving contrast and suppressing mutual interference between the subcells and the pixel cells, thereby improving display performance. . By making the width of the sub barrier rib separating the subcells smaller than the width of the main barrier separating the pixel cells, the application area of the discharge space and the phosphor is increased, thereby improving the discharge efficiency and the brightness. Since the blackened partition wall is used, there is no need to form a separate black mattress layer for improving contrast, thereby preventing the problem of deterioration in luminance due to the use of the black mattress. The discharge space of each of the subcells emitting red (R), green (G), and blue (B) light has a different size according to the visible light generation efficiency of each phosphor, thereby achieving balanced light emission from each subcell. This is done. By manufacturing the barrier ribs by the etching method of the photosensitive glass substrate, not only the precise barrier ribs having a large aspect ratio can be manufactured, but also the manufacturing process is simple, thereby further enhancing the competitiveness of the display.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (8)

A main partition wall for distinguishing pixel cells including subcells corresponding to each of red, green, and blue, And a sub-barrier having a width narrower than that of the main partition and separating the sub-cells. The method of claim 1, The height of the sub-barrier and the main partition wall is 100 ~ 500㎛, the width of the sub-barrier is between 20 ~ 50㎛, the plasma display panel, characterized in that the width of the main partition wall is 70 ~ 200㎛. The method of claim 1, And a thermal expansion coefficient of the sub barrier ribs and the main barrier rib is 80 × 10 ⁻⁷ / K to 90 × 10 ⁻⁷ / K. The method of claim 1, And the subcells have different sizes. The method of claim 4, wherein And the size of the subcells is inversely proportional to the visible light emission efficiency of the phosphors applied in the subcells. The method of claim 1, And the main and sub barrier ribs are blackened. The method of claim 6, And the main and sub barrier ribs are blackened by a crystallization method. The method of claim 6, And the main and sub barrier ribs are blackened by applying a black matrix on the barrier ribs.