Patent Application
20080038985
1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to a plasma display panel, in which a differential dielectric is formed on an upper plate to reduce breakdown voltage and discharge current, and a method for manufacturing the same.
2. Discussion of the Related Art
Generally, in a plasma display panel, discharge cells are divided from each other by barrier ribs formed between a front substrate and a rear substrate. Each of the discharge cells is filled with a main discharge gas, such as neon gas, helium gas, or neon-helium mixed gas, and an inactive gas containing a small amount of xenon. When an electric discharge occurs by means of a high-frequency voltage, the inactive gas generates vacuum ultraviolet rays, and the vacuum ultraviolet rays cause fluorescent materials between the barrier ribs to emit light, thereby forming an image. The above-described plasma display panel has a small thickness and a light weight, thus being spotlighted as the next generation display device.
Barrier ribs 112 formed in a stripe type (or a well type) for forming a plurality of discharge spaces, i.e., discharge cells, are arranged in parallel on the rear substrate 110. Further, a plurality of the address electrodes 113 for performing address discharge to generate vacuum ultraviolet rays are arranged in parallel with the barrier ribs 112. R, G, B fluorescent materials 114 or emitting visible rays to display an image when the address discharge occurs are applied to the upper surface of the rear substrate 110. A lower dielectric layer 115 for protecting the address electrodes 113 is formed between the address electrodes 113 and R, G, B fluorescent materials 114.
The above conventional plasma display panel is manufactured through a glass-manufacturing process, a front substrate-manufacturing process, a rear substrate-manufacturing process, and an assembling process.
First, the front substrate-manufacturing process includes forming scan electrodes and sustain electrodes on a front glass, forming an upper dielectric layer for limiting discharge current of the scan and sustain electrodes and insulating pairs of the scan and sustain electrodes from each other, and forming a protection layer on the upper dielectric by depositing magnesium oxide for facilitating the discharge condition
The rear substrate-manufacturing process includes forming address electrodes on a rear glass, forming a lower dielectric layer for protecting the address electrodes, forming barrier ribs on the upper surface of the lower dielectric layer for dividing discharge cells from each other, and forming a fluorescent material layer on regions between the barrier ribs for emitting visible rays.
The above plasma display panel and the method for manufacturing the same have problems, as follows.
In order to improve the light-emitting efficiency of the plasma display panel, it is necessary to reduce discharge current. The discharge current is influenced by the thickness of the dielectric layer. Generally, when the dielectric layer has a small thickness, breakdown voltage is decreased and discharge current is increased, and when the dielectric layer has a large thickness, the breakdown voltage is increased and the discharge current is decreased. Accordingly, when the thickness of the dielectric layer is simply increased, the discharge current is decreased, but the breakdown voltage is increased.
In order to solve the above problem, the formation of a differential dielectric layer having different thicknesses according to regions on the upper plate has been proposed. That is, grooves or protrusions are formed on the dielectric layer, thus improving the discharge efficiency of the plasma display panel and reducing power consumption.
The formation of the differential dielectric layer is achieved by a screen printing method or a sanding method.
The screen printing method has a simple process and requires low-priced equipment, but deteriorates the uniformity of the thickness and the width of a layer to be formed, thus lowering the accuracy of a fine definition pattern. Further, the screen printing method leaves mesh marks of a screen mask even after a baking process, thus lowering a surface roughness. Particularly, in a large-sized panel, the screen printing method deforms the screen mask, thus causing disagreement of patterns.
The sanding method is a method in that a dielectric layer is selectively cut using kinetic energy of cutting particles, such as ceramic particles or ultrafine particles of calcium carbonate through a mask patterned on the dielectric layer, thus forming a differential dielectric. The sanding method is capable of produce the differential dielectric having a line width of less than 50 μm. However, the sanding method causes environmental contamination due to dust, and cracks in a fine-definition pattern due to the crushing energy of the cutting particles.
Accordingly, the present invention is directed to a dielectric sheet, a plasma display panel using the same, and a manufacturing method therefor.
One object of the present invention is to provide a dielectric sheet having a double-layered structure, a plasma display panel using the same, and a manufacturing method therefor.
To achieve this object and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a dielectric sheet includes a first layer including a photosensitive material; and a second layer including a nonphotosensitive material.
In a further aspect of the present invention, a plasma display panel includes an upper plate provided with a dielectric comprising a first layer including a photosensitive material and a second layer including a nonphotosensitive material; and a lower plate provided with barrier ribs.
In another aspect of the present invention, a method for manufacturing a plasma display panel includes forming a dielectric sheet comprising at least one layer including a photosensitive material, on an upper glass provided with pairs of retaining electrodes; and exposing the dielectric sheet to light, and developing the dielectric sheet.
In another aspect of the present invention, a dielectric sheet includes a first layer, which dissolves in a developing solution; and a second layer, which does not dissolve in the developing solution.
In another aspect of the present invention, a plasma display panel includes an upper plate provided with a dielectric comprising a first layer, which dissolves in a developing solution, and a second layer, which does not dissolve in the developing solution; and a lower plate provided with barrier ribs.
In another aspect of the present invention, a method for manufacturing a plasma display panel includes forming a dielectric sheet, comprising a photoresist layer and a layer made of a material, which dissolves in a developing solution, on an upper glass provided with pairs of retaining electrodes; and exposing the dielectric sheet to light, and developing the dielectric sheet.
In another aspect of the present invention, a dielectric sheet includes a base film; a light-heat conversion layer formed on the base film for absorbing light and generating heat; and a dielectric material layer formed on the light-heat conversion layer.
In yet another aspect of the present invention, a method for manufacturing a plasma display panel includes forming a first dielectric on an upper glass provided with pairs of retaining electrodes; mounting a dielectric sheet comprising a base film, a light-heat conversion layer, and a dielectric material layer on the first dielectric; and forming a second dielectric by irradiating light onto the dielectric sheet.
It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
A dielectric sheet of the present invention has at least two layers made of materials having different properties, and a differential dielectric of a plasma display panel is formed using the dielectric sheet.
The dielectric sheet of the first embodiment comprises a first film 200, a first layer 210, a second layer 220, and a second film 230. The first film 200 and the second film 230 are used in a process for manufacturing and carrying the dielectric sheet, and the first layer 210 and the second layer 220 are substantially used to form a differential dielectric of a plasma display panel. Preferably, the first layer 210 includes a photosensitive material, and the second layer 220 includes a nonphotosensitive material.
First, as shown in
Thereafter, as shown in
In
In
The plasma display panel in accordance with the first embodiment is characterized in that the dielectric layer comprises two layers respectively containing a photosensitive material and a nonphotosensitive material and the thickness of the layer containing the photosensitive material is not uniform.
The dielectric sheet of the second embodiment comprises a first filt 400, a second layer 410, a first layer 420, a photoresist layer 430, and a second film 440, which are sequentially provided. The first layer 220 and the second layer 410 are used to manufacture a dielectric, and thus contain dielectric powder, a dispersant, and a plasticizer. Preferably, the first layer 420 further contains a material, which dissolves in a developing solution, and the second layer 410 further contains a material, which does not dissolve in the developing solution. The material, which dissolves in the developing solution, is preferably a polymeric organic matter, and more preferably an acrylic organic matter. Preferably, the developing solution is water or an alkaline water solution. The photoresist layer 430, which is formed on the first layer 420, is used to selectively develop the first layer 420 through exposing and developing processes in a method for manufacturing a plasma display panel, which will be described later. The first film 400 and the second film 440 are made of Polyethylene terephthalate (PET).
In this method, a differential dielectric is formed on the plasma display panel using the above dielectric sheet of the second embodiment. First, as shown in
Thereafter, as shown in
Thereafter, after the dielectric sheet is developed, the dielectric sheet is baked, thus forming a differential dielectric, as shown in
A protection layer made of magnesium oxide is formed on the above differential dielectric by CVD or ion plating. Thereby, the manufacture of an upper plate of the plasma display panel is completed. The above method shortens a time to form the differential dielectric, simplifies a process for forming the differential dielectric, and improves the uniformity of the thickness of the dielectric layer.
In the plasma display panel manufactured by the above method, the differential dielectric having the first layer, which dissolves in the developing solution, and the second layer, which does not dissolve in the developing solution, is formed on the upper plate. The first layer has a differential thickness, thus forming the differential dielectric.
The dielectric sheet 600 of the third embodiment comprises a base film 610, a light-heat conversion layer 620, and a dielectric material layer 640, which are sequentially provided. Preferably, an emission layer 630 is formed between the light-heat conversion layer 620 and the dielectric material layer 640.
When a laser beam is irradiated onto the dielectric sheet of this embodiment, light energy of the laser beam is converted into heat energy by the light-heat conversion layer 620, and the dielectric material layer 640 is selectively transcribed by the heat energy, thus forming a differential dielectric. Hereinafter, the composition of the dielectric sheet is described in detail.
The base film 610 is made of a material, which transmits light, preferably, a laser beam. More preferably, the base film 610 is made of a transparent polymer. The polymer is one selected from the group consisting of polyester, such as PET, polyacryl, polyepoxy, polyethylene, and polystyrene. Most preferably, the base film 610 is made of PET. Further, preferably, the base film 610 has a thickness of 10˜500 □. Since the base film 610 supports the dielectric sheet 600, the base film 610 may be made of a polymeric composite. However, in order to prevent the base film 610 from being decomposed by the heat generated from the light-heat conversion layer 620, the base film 610 is preferably made of a material having a high decomposition temperature.
Preferably, the light-heat conversion layer 620 is made of a light absorption material, which absorbs a light energy source. More preferably, the light-heat conversion layer 60 is made of at least one selected from the group consisting of metals, metal oxides, and metal sulfides, or made of an organic matter including at least one selected from the group consisting of carbon black, graphite, and laser beam absorption materials.
The metals include aluminum, silver, chrome, tin, nickel, titanium, cobalt, zinc, gold, copper, tungsten, molybdenum, lead, and their alloys. Preferably, aluminum, silver, and their alloy are used.
Preferably, an infrared pigment is added to the organic matter. More preferably, the organic matter includes a polymeric bonding resin, and a coloring agent, such as a pigment and/or a dye, and a dispersant, which are dispersed in the polymeric bonding resin. The polymeric bonding resin may independently use (meta)acrylate oligomer, such as acryl(meta)acrylate oligomer, ester(meta)acrylate oligomer, epoxy(meta)acrylate oligomer, or urethane(meta)acrylate oligomer. Further, the polymeric bonding resin may use a mixture of (meta)acrylate oligomer and (meta)acrylate monomer, or independently use (meta)acrylate monomer. Preferably, carbon black and graphite have a particle diameter of less than 0.5 □, and an optical concentration of 0.1˜4.
The dielectric material layer 640 is made of a material of the conventional dielectric layer, and uses PbO—B2O3-SiO2-based, ZnO—B2O3-SiO2-based, or PbO—SiO2-Al2O3-based glass particles. Preferably, the dielectric material layer 640 includes a binder, which is decomposed by the heat generated from the light-heat conversion layer 620. Further, the binder has a decomposition temperature (Td), which is preferably lower than that of the base film 610, and more preferably less than 350 □.
Preferably, the binder includes at least one selected from the group consisting of polypropylene carbonate, poly(alpha-methyl)stytene, polymethyl methacrylate, polybutyl methacrylate, cellulose acetate butyrate, nitrocellulose, polyvinyl chloride, poly(chlorovinyl)chloride, polyacetal polyurethane, polyester, polyactylonitrile, maleic acid resin, and their copolymers.
Further, a photoresist may be used as the binder. The binder is preferably a film, and more preferably a film, which can be coated with a solution or a dispersion solution. In order to exhibit a transcribing effect, which will be described later, more preferably, a binder, which has a melting point of below approximately 250 □, or is plasticized at a glass transition temperature of below 70 □, is used. A binder, which is easily liquefied or thermally melted, for example, a low-melting wax, is used as a common binder for lowering the melting point of a texture. However, when the above binder has low flowability and durability, the binder is not used independently.
Preferably, the emission layer 630 includes a material for increasing transcribing ability so that the dielectric material layer 640 can be more effectively transcribed. That is, in order to provide pressure required to emit exposed regions, the emission layer 630 includes a foaming agent, which causes a decomposition reaction to emit nitrogen gas or hydrogen gas when it absorbs light or heat. For example, the foaming agent is pentaerythritol tetranitrate (PETN) or trinitrotoluene (TNT).
In this method, a differential dielectric is formed on the plasma display panel using the above dielectric sheet of the third embodiment. First, as shown in
Thereafter, as shown in
Thereafter, as shown in
When the laser beam is irradiated, the laser beam passes through the base film 610, activates the light-heat conversion layer 620, and emits heat due to pyrolysis. The emitted heat melts or decomposes the binder of the dielectric material layer 640, and causes the decomposition reaction in the emission layer 630. Then, the emission layer 630 is expanded, and the dielectric material layer 640 is separated from the dielectric sheet 600 and is transcribed onto the first dielectric 700.
Thereafter, when the dielectric sheet 600 is separated from the first dielectric 700, since portions of the dielectric material layer 640, onto which the laser beam is not irradiated, are bonded to the light-heat conversion layer 620, the portions of the dielectric material layer 640 are separated from the first dielectric 700. Accordingly, portions of the dielectric material layer 640, onto which the laser beam is irradiated, are transcribed onto the first dielectric 700, and form a differential dielectric, as shown in
The method of the third embodiment does not use an expensive photo mask and does not requires the developing process, thus reducing the production costs of plasma display panels and allowing mass production of large-sized plasma display panels.
Processes forming other parts except for the process forming the upper dielectric in the above methods in accordance with the embodiments of the present invention are the same as those in the conventional method.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2005-0061739 | Jul 2005 | KR | national |
| 10-2005-0072873 | Aug 2005 | KR | national |
| 10-2005-0135571 | Dec 2005 | KR | national |
This application is a Continuation Application of prior U.S. patent application Ser. No. 11/482,196 filed Jul. 7, 2006, which claims priority under 35 U.S.C. §119 to Korean Application No. 10-2005-0061739, filed on Jul. 8, 2005, Korean Patent Application No. 10-2005-0072873, filed on Aug. 9, 2005, and Korean Patent Application No. 10-2005-0135571, filed on Dec. 30, 2005, which are hereby incorporated by reference as if fully set forth herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11482196 | Jul 2006 | US |
| Child | 11831411 | Jul 2007 | US |
