KR100425434B1 - Method of fabricating back plate of plasma display panel - Google Patents

Abstract

The present invention relates to a method for manufacturing a lower panel of a plasma display panel in which a driving IC can be mounted without any additional equipment.

The lower plate manufacturing method of the plasma display panel according to the present invention includes a first step of forming a green sheet on a metal substrate; Forming an electrode layer on the green sheet; Printing an electrode protective film having a via hole exposing a part of the electrode layer on the electrode layer and the green sheet; A fourth step of connecting the electrode layers to each other through the via hole by repeating the second step and the third step a plurality of times; Pressurizing the green sheet with a mold to form a partition wall; A sixth step of simultaneously firing the green sheet and the partition wall on which the plurality of electrode layers and the electrode protective film are formed; And a seventh step of forming a single input terminal on the metal substrate to be connected to the electrode layer formed on the green sheet.

Description

Manufacturing method of lower panel of plasma display panel {METHOD OF FABRICATING BACK PLATE OF PLASMA DISPLAY PANEL}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a method for manufacturing a lower panel of a plasma display panel in which a driving IC can be mounted without additional equipment.

Plasma Display Panels (hereinafter referred to as "PDPs") display an image including characters or graphics by emitting phosphors by ultraviolet rays of 147 nm generated upon discharge of He + Xe or Ne + Xe gas. Such a PDP is not only thin and easy to enlarge, but also greatly improved in quality due to recent technology development.

Referring to FIG. 1, an AC drive type PDP including a lower substrate 14 on which an address electrode 2 is mounted and an upper substrate 16 on which a pair of sustain electrodes 4 are mounted is illustrated. On the lower substrate 14 on which the address electrode 2 is mounted, a partition wall 8 for dividing the dielectric thick film 18 and the discharge cells is formed. The phosphor 6 is coated on the surfaces of the dielectric thick film 18 and the partition wall 8. The phosphor 6 emits light by ultraviolet rays generated at the time of plasma discharge so that visible light is generated. The dielectric layer 12 and the passivation layer 10 are sequentially formed on the upper substrate 16 on which the sustain electrode pairs 4 are mounted. The dielectric layer 12 accumulates wall charges during plasma discharge, and the protective layer 10 protects the pair of sustain electrodes 4 and the dielectric layer 12 from sputtering of gas ions during plasma discharge, and discharge efficiency of secondary electrons. It serves to increase. The discharge cells of the PDP are filled with a mixed gas of He + Xe or Ne + Xe.

The partition 8 serves to prevent electrical and optical crosstalk between discharge cells. Therefore, the partition wall 8 is the most important factor for display quality and luminous efficiency, and various studies on the partition wall 8 have been made as the panel is enlarged and fixed in size. Screen printing method, sand blasting method, Additive, photosensitive paste method, and Low Temperature Cofired Ceramic on Metal (LTCC-M) method are applied as a method of manufacturing the partition 8. have.

The screen printing method has the advantages of a simple process and low manufacturing cost, but there is a problem of repeating the screen and glass substrate 14 alignment, printing and drying of the glass paste several times in every printing. In addition, when the position of the screen and the glass substrate is shifted, the partition wall is deformed, so that the shape accuracy of the partition wall is lowered.

The sand blasting method has a merit of forming a partition on a large-area substrate, but a large amount of glass paste removed by the abrasive (sand particles) has a disadvantage of wasting material and manufacturing cost. In addition, the glass substrate 14 is impacted by the abrasive, and thus the glass substrate 14 is cracked or damaged.

The addition method has an advantage in that the partitions 8 are formed on the large-area substrate, but it is difficult to separate the photoresist and the glass paste so that a residue remains or the partitions are collapsed when forming the partition.

The photosensitive paste method is not only difficult to expose the photosensitive paste to the lower portion of the photosensitive paste, but also has a disadvantage that the photosensitive paste is expensive.

LTCC-M method has the advantages of low temperature process and simple process compared to other bulkhead manufacturing method.

2A to 2G show a method of manufacturing a partition wall using the LTCC-M method step by step. First, the green sheet 30 as shown in Figure 2a is produced. The green sheet 30 is manufactured by drying a slurry in which a glass powder, an organic solution, a plasticizer, a binder, an additive, and the like are mixed in a predetermined ratio on a polyester film, and forming a sheet in a doctor blading, followed by drying. . As a material of the substrate 32 to which the green sheet 30 is bonded, a metal, for example, titanium (Titanum) is usually used. Titanium may be manufactured to have a thickness thinner than that of other glass and ceramic materials because of its greater strength and heat resistance than glass or ceramic substrates, and may reduce thermal and mechanical deformation of the substrate 32. In addition, since titanium has a high reflectance, light emission efficiency and luminance may be increased by reflecting visible light that is transmitted toward the substrate 32, that is, back scattered, toward the display surface.

Subsequently, the green sheet 30 is laminated and bonded to the substrate 32 as shown in FIG. 2B, and the address electrode 2 is formed on the green sheet 30 as shown in FIG. 2C.

On the substrate 30 on which the address electrode 2 is formed, as shown in FIG. 2D, the dielectric paste is completely printed and then dried to form an electrode protective layer 36. After the electrode protective layer 36 is formed, secondary laminating is performed to increase adhesion between the green sheet 30 having the address electrode 2 and the electrode protective layer 36. Subsequently, in order to increase the fluidity of the green sheet 30 bonded to the substrate 32, the substrate 32 is heated to a temperature lower than or equal to the softening point of the organic material used as the binder.

In the state where the fluidity of the green sheet 30 is increased, as shown in FIG. 2E, the mold 38 having the groove 38a having the opposite shape to the partition wall is aligned on the substrate 32.

The mold 38 is then pressed onto the substrate 32 at a pressure of about 150 kgf / cm 2 or more, as shown in FIG. 2F. When the mold 38 is pressed, the green sheet 30 and the electrode protective layer 36 are moved into the groove 38a of the mold 38 to rise.

After the mold 38 is separated from the green sheet 30 and the electrode protective layer 36 as shown in FIG. 2G, the partition 8 is fired while passing through a temperature raising, holding, and cooling zone. In this firing process, after the burnout (Binder burn out) of the organic material in the green sheet 30 is burned out, crystal nuclei are formed and grown on the inorganic materials at a temperature higher than the burnout.

The address electrode 2 and the sustain electrode pair 4 of the PDP are driven by signals supplied from driver integrated circuits (hereinafter referred to as " IC "). These driver ICs are mounted on a printed circuit board (hereinafter, referred to as a "PCB") board and are mounted on a substrate 32 via a flexible printed circuit (FPC). It is generally connected to the address electrode 2 and the sustain electrode pair 4 on the image.

Recently, a method in which driver ICs are mounted on the metal substrate 32 as shown in FIG. 3 using the LTCC-M method, or the metal circuit 32 and the driving circuit are integrated as shown in FIG. 4 has been proposed.

Referring to FIG. 3, a bottom plate of a PDP is shown in which driver IC packages 44 are bonded onto a metal substrate 32 in a ball grid array manner. In the display area, a low-temperature baking green sheet for forming a partition wall is bonded on the metal substrate 32. Input terminals of the driver IC packages 44 mounted on the metal substrate 32 are connected to an external main PCB via the FPC 42 or the input wires.

According to the lower plate of the PDP as shown in FIG. 3, not only the mounting process of the driver IC packages 44 is required, but also the external signal input terminals of the driver IC packages 44 are separately formed on the metal substrate 32. A number of FPCs 42 are needed to connect the driver IC packages 44 and the external main PCB. In addition, when the number of electrode wirings on the bottom plate increases due to the high resolution, since many driver IC packages 44 must be installed on the limited bottom plate, component installation space is limited, and the input wiring lines and the number of input wiring lines may be shorted or shorted. have.

Referring to FIG. 4, at the bottom of the PDP proposed in Korean Patent Application No. 10-1998-0050911 filed by the applicant of the present application (Nov. 26, 1998), a driving circuit is integrated with the metal substrate 32 and the driver IC package 44 ) Is joined. An upper ceramic layer 46A is formed on the front surface of the metal substrate 32 to insulate the address electrode 2, and a driving circuit for driving the address electrode 2 is mounted on the rear surface of the metal substrate 32. First and second lower ceramic layers 46B and 46C are stacked. The upper and lower ceramic layers 46A, 46B, 46C are formed by laminating the green sheet on the metal substrate 32 and simultaneously firing. The address electrode 2 and the driving circuit are connected via the via holes 48 penetrating the ceramic layers 46A, 46B, 46C and the metal substrate 32. The inner wall of the via hole 48 is coated with an insulating film for insulation between the metal substrate 32 and the signal wiring. A driving circuit is patterned in the lower ceramic layers 46B and 46C, which are electrically connected to the driver IC package 44.

The lower plate of the PDP as shown in FIG. 4 has a disadvantage in that it is difficult to form fine via holes on the metal substrate 32 and a process for additionally coating an insulating film therein is required.

In order to solve the shortcomings of the method of mounting the driver IC as shown in FIGS. 3 and 4, the applicant of the present invention proposes a multilayer ceramic formed using a green sheet on the metal substrate 32 as shown in FIG. A method of manufacturing a lower plate of a PDP has been proposed in which an electrode pattern is mounted on the layer 50 and the driver IC package 44 is mounted thereon. In the lower plate of this PDP, since the input electrode pattern is formed on the multilayer ceramic layer 50, the input terminal 52 is comprised singly.

The manufacturing method of the lower plate of the PDP is shown in Figs. 6A to 6L.

First, the partition sheet green sheet 60 is laminated and bonded to the metal substrate 52 as shown in FIG. 6A. On the metal substrate 52 to which the partition sheet green sheet 60 is bonded, an electrode material is printed and dried as shown in FIG. 6B to form an address electrode 2. On the metal substrate 52 on which the address electrode 2 is formed, as shown in FIG. 6C, the dielectric paste is completely printed and then dried to form the electrode protective layer 64. The electrode protective layer 64 and the partition sheet green sheet 60 are secondarily laminated on the metal substrate 52 to increase the bonding force therebetween. Subsequently, the metal substrate 52 is heated below the softening point of the organic material used as the binder of the green sheet 60 in order to increase the fluidity of the partition sheet green sheet 60 bonded on the substrate 52.

In the state where the flowability of the partition forming green sheet 60 is increased, the metal substrate at a pressure of about 150 kgf / cm 2 or more after the die 66 having the grooves having the shape opposite to the partition wall is aligned on the metal substrate 52 as shown in FIG. 6D. Is pressed onto 52. When the mold 66 is pressurized, the partition sheet green sheet 60 and the electrode protective layer 64 are moved into the groove of the mold 66 to rise in the form of a partition wall.

The mold 66 is separated from the partition sheet green sheet 60 and the electrode protective layer 64 as shown in FIG. 6E.

6B to 6J, the barrier 8 is formed and the electrode printing and the protective film forming process are repeated using the green sheet 68 to form the multilayer ceramic layer 50 in the desired number of layers. The green sheet 68 is manufactured by drying a slurry in which a glass powder, an organic solution, a plasticizer, a binder, an additive, and the like are mixed in a predetermined ratio in the form of a thin plate like the partition sheet forming green sheet 60. Via-holes 68a for electrically connecting the electrodes formed in the respective layers are punched on the green sheet 68 as shown in FIG. 6G. The via hole 68a is filled with an electrode material 70 printed on the green sheet 68 as shown in FIG. 6H. Subsequently, the electrode pattern 72 is formed on the green sheet 68 as shown in FIG. 6I by the front printing method of the electrode material. The electrode pattern is electrically connected to the lower layer electrode via the via hole 68a. The electrode protective layer 74 is formed on the green sheet 68 on which the electrode pattern 72 is formed by drying after the dielectric slurry is printed on the entire surface as shown in FIG. 6J.

When the green sheets 68 on which the electrode patterns 72 are formed are fabricated as many as desired layers, they are bonded in multiple layers. The multilayer ceramic layer 50 is co-fired with the formed partition wall 8 after being aligned on the partition forming green sheet 60 located in the non-display area on the metal substrate 52 as shown in FIG. 6K. In this firing process, the green sheets 60 and 68 and the electrode protective layers 64 and 74 are fired while being heated, maintained, and cooled. In this firing process, after the burnout in which the organic materials in the green sheets 60 and 68 are burned away, crystal nuclei are formed and grown on the inorganic materials at temperatures higher than the burnout.

Finally, as shown in FIG. 6L, the driver IC package 44 is aligned on the multilayer ceramic layer 50, and the driver IC package 50 is formed by the reflow process for melting the solder ball 43. It is mounted on.

The electrodes formed on the respective layers of the multilayer ceramic layer of the PDP are electrically connected to the electrodes of the other layers via via holes. In order to drill such a via hole, there is a disadvantage that an expensive automatic drilling equipment is additionally required. In addition, the existing automatic drilling equipment is set to puncture a small area of the green sheet, so the automatic drilling equipment must be scaled up to be applied to the green sheet in a large area, and there is a problem in that the investment cost is high. In addition, since a plurality of alignment pins must be formed as shown in FIG. 7 in order to precisely align and stack each green sheet of the multilayer ceramic layer, an expensive automatic alignment device additionally has a disadvantage.

Accordingly, an object of the present invention is to provide a method for manufacturing a lower panel of a plasma display panel in which a driving IC can be mounted without additional equipment.

1 is a perspective view showing a surface discharge type PDP of an AC drive system.

2A to 2G are cross-sectional views illustrating a method of manufacturing a lower plate of a PDP using a conventional LTCC-M method.

3 is a perspective view schematically illustrating a lower plate of a conventional plasma display panel in which a driver IC package is directly mounted on a lower substrate.

4 is a cross-sectional view schematically illustrating a lower plate of a conventional plasma display panel in which a driving circuit is integrated on a lower substrate.

FIG. 5 is a perspective view illustrating a bottom plate of a conventional plasma display panel in which an input electrode pattern is mounted on a substrate to simplify an input terminal. FIG.

6A to 6L are cross-sectional views illustrating in detail the bottom structure of the plasma display panel shown in FIG. 5;

FIG. 7 is a cross-sectional view illustrating an alignment pin for aligning via holes of the plasma display panel illustrated in FIG. 5.

8A through 8H are cross-sectional views illustrating a method of manufacturing a lower plate of a plasma display panel according to an exemplary embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

2: address electrode 4: sustain electrode pair

6: phosphor film 8: partition wall

10: protective film 12,18: dielectric thick film

14,32,62: lower substrate 16: upper substrate

30,46A, 46B, 46C, 60: Green sheet 36,54,64,74: Electrode protective layer

38: mold 42: FPC

43,74: Lead 44,72: Driver IC Package

50: ceramic layer 80: single external signal input terminal

In order to achieve the above object, the lower plate manufacturing method of the plasma display panel according to the present invention comprises a first step of forming a green sheet on a metal substrate; Forming an electrode layer on the green sheet; Printing an electrode protective film having a via hole exposing a part of the electrode layer on the electrode layer and the green sheet; A fourth step of connecting the electrode layers to each other through the via hole by repeating the second step and the third step a plurality of times; Pressurizing the green sheet with a mold to form a partition wall; A sixth step of simultaneously firing the green sheet and the partition wall on which the plurality of electrode layers and the electrode protective film are formed; And a seventh step of forming a single input terminal on the metal substrate to be connected to the electrode layer formed on the green sheet.

The lower plate manufacturing method of the plasma display panel according to the present invention further includes an eighth step of mounting the driver integrated circuit package on the fired green sheet.

Other objects and features of the present invention in addition to the above object will become 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. 8A to 8H.

8A to 8H show step by step manufacturing a lower plate of the PDP according to the present invention. First, the partition sheet green sheet 60 is manufactured. The partition sheet green sheet 60 is dried after forming a slurry in which a glass powder, an organic solution, a plasticizer, a binder, an additive, and the like are mixed in a predetermined ratio on a polyester film and forming a sheet by Doctor Blading. Produced by

The green sheet 60 is laminated and bonded to the metal substrate 62 as shown in FIG. 8A. On the metal substrate 62 to which the green sheet 60 is bonded, as shown in FIGS. 8B to 8F, the electrode printing and the protective film forming process are repeated to form the multilayer electrode layer and the electrode protective film as many as desired layers.

In detail, as illustrated in FIG. 8B, the electrode material is printed and dried to form the first electrode layer 66a. The electrode paste used in forming the first electrode layer 66a has a composition that closely matches the shrinkage rate during firing so that cracks and deformations do not occur when the barrier sheet green sheet 60 is simultaneously baked. The first electrode passivation layer 64a and the first via hole 68a are formed on the metal substrate 62 on which the first electrode layer 66a is formed by drying after printing the dielectric paste as shown in FIG. 8C. The electrode protective film is formed of a dielectric layer and a protective layer. The dielectric paste for forming the first electrode protective film 64a is formed of an inorganic material having the same composition as that of the first electrode layer 66a so as not to cause cracks or deformation when simultaneously firing with the first electrode layer 66a. The first via hole 68a is formed through the first electrode passivation layer 64a to expose the first electrode layer 66a.

Subsequently, an electrode material is printed and dried on the first electrode protective film 64a as shown in FIG. 8D to form a second electrode layer 66b. The electrode paste used in forming the second electrode layer 66b has a composition that closely matches the shrinkage ratio during firing so that cracks and deformations do not occur during simultaneous firing with the partition sheet green sheet. The second electrode layer 66b is in electrical contact with the first electrode layer 66a through the first via hole 68a. On the metal substrate 62 on which the second electrode layer 66b is formed, as shown in FIG. 8E, the dielectric paste is printed and then dried to form the second electrode passivation layer 64b and the second via hole 68b. The dielectric paste forming the second electrode protective film 64b is formed of an inorganic material having the same composition as that of the second electrode layer 66b so that cracks and deformations do not occur when co-firing with the second electrode layer 66b. The second via hole 68b is formed through the second electrode protection film 64b to expose the second electrode layer 66b.

In the same manner as the first and second electrode layers 66a and 66b and the first and second electrode protective films 64a and 64b, the third electrode layer and the third protective film are formed as shown in FIG. An electrode layer is formed.

After the plurality of electrode layers are formed on the metal substrate 62, the metal substrate 62 is heated below the softening point of the organic material used as a binder of the green sheet 60 to increase the fluidity of the green sheet 60 positioned in the display area. .

In the state where the flowability of the green sheet 60 is increased, the mold having the grooves opposite to the partition wall is aligned on the metal substrate 62 and then pressed on the metal substrate 62 at a suitable pressure. When the mold is pressurized, the partition forming green sheet and the electrode protective film are moved into the groove of the mold to rise in the form of the partition as shown in FIG. 8G. The mold 66 is separated from the partition sheet green sheet and the electrode protective layer.

After forming the barrier rib 70, a firing process is performed to densify the green sheet 60, the multilayer electrode protective film, and the electrode layer. In this firing process, after the burnout in which the organic materials in the green sheet 60 are burned away, crystal nuclei are formed and grown on the inorganic materials at temperatures higher than the burnout.

Finally, as shown in FIG. 8H, the driver IC package 72 is aligned on the plurality of electrode layers 50 and the driver IC package 72 is formed by the reflow process for melting the solder 74. It is mounted on.

As described above, the lower plate of the PDP and the manufacturing method thereof according to the present invention are formed by printing a plurality of electrode layers and electrode protective film. Accordingly, since the via holes for connecting the plurality of electrode layers are formed at the same time as the electrode protective film formed by the printing method, the automatic alignment apparatus and the automatic drilling apparatus, which are conventional expensive equipment, are unnecessary. That is, since the via hole can be formed without expensive equipment, the device cost can be reduced. In addition, since the via hole is formed at the same time as the electrode protective film formed by the printing method, it can be applied to a large area green sheet.

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 (2)

Forming a green sheet on the metal substrate; Forming an electrode layer on the green sheet; Printing an electrode protective film having a via hole exposing a part of the electrode layer on the electrode layer and the green sheet; A fourth step of connecting the electrode layers to each other through the via hole by repeating the second step and the third step a plurality of times; Pressurizing the green sheet with a mold to form a partition wall; A sixth step of simultaneously firing the green sheet and the partition wall on which the plurality of electrode layers and the electrode protective film are formed; And forming a single input terminal on the metal substrate so as to be connected to an electrode layer formed on the green sheet. The method of claim 1, And a eighth step of mounting a driver integrated circuit package on the fired green sheet.