Patent Grant
6986694
1. Field of the Invention
The present invention relates to a plasma display panel, and in particular to a method for removing impurities of a plasma display panel which is capable of shortening a panel aging time.
2. Description of the Prior Art
In general, according to development and popularization of information processing system, importance of a display apparatus as a visual information transfer means has been increased.
In the conventional display apparatus, a CRT (cathode ray tube) is bulky and has an image distortion problem due to an earth magnetic field. In the meantime, recent various display apparatus aim for oversize, flatness, high brightness, high efficiency in screen. Accordingly, researches on various flat panel displays have been actively going on. For example, in the flat panel display, a LCD (liquid crystal display), a FED (field emission display) and a PDP (plasma display panel), etc. have been developed.
The PDP (plasma display panel) displays pictures including character or graphic by radiating fluorescent material by ultraviolet rays generated in discharge of a mixed gas such as He+Xe, Ne+Xe and He+Ne+Xe, etc. Thinning and scale-up of the PDP can be easily achieved. Because the PDP has a simple structure, it is easy to fabricate. In addition, it has a higher brightness and luminous efficiency in comparison with other flat panel displays. Because of those advantages, researches on PDP have been actively going on. In particular, in a three electrodes alternating current surface discharge type PDP, because wall electric charge is accumulated on the surface in discharge and electrodes are protected from sputtering in discharge, it is possible to perform a low voltage operation and have a long life span.
As depicted in
In addition, a lower panel includes a lower glass substrate 26; an address electrode 22 formed at the top surface of the lower glass substrate 26; a lower dielectric layer 24 formed at the whole top surface of the address electrode 22; a separation wall 20 formed at the top surface of the lower dielectric layer 24 in parallel with the address electrode 22; and a fluorescent material 18 coated onto the separation wall 20 and radiating visible rays by excitation of ultraviolet rays.
The fabrication process of the general three electrodes alternating current surface discharge type plasma display panel will be described.
The sustain electrodes 12 are arranged at the bottom surface of the upper glass substrate 10 in parallel. In more detail, the sustain electrode 12 consists of an ITO (indium tin oxide) electrode 12A and a bus electrode 12B which are pasted in Cr/Cu/Cr or silver (Ag). The sustain electrode 12 supplies a scan signal for address discharge and a sustain signal for sustain discharge. The dielectric layer 14 for electric, charge is coated onto the upper panel on which the sustain electrode 12 is arranged by a screen printing method, and a protecting film 16 is formed on the surface of the dielectric layer 14.
Herein, the protecting film 16 extends a life of the dielectric layer 14, improves secondary electron discharge efficiency and reduces discharge characteristics variation of fireproof metal due to oxide contamination by protecting the dielectric layer 14 from the sputtering phenomenon of plasma particles. A MgO (magnesium oxide) film is mainly used as the protecting film 16.
In addition, the fabrication method of the lower panel will be described.
In the lower panel, the address electrode 22 is formed by the screen printing method. The address electrode 22 supplies a data signal for address discharge. The lower dielectric layer 24 is formed at the top surface of the lower glass substrate 26 on which the address electrode 22 is formed. The separation wall 20 is formed on the top surface of the dielectric layer 12 on which the address electrode 22 is formed by the screen printing method or a sand blast method so as to be parallel with the address electrode 22. In more detail, the separation wall 20 provides a discharge space inside the discharge cells in order to cut off electrical and optical interference between discharge cells and performs a function for supporting the upper panel and the lower panel.
The fluorescent material 18 for generating visible rays is formed onto the surface of the lower dielectric layer 24 in which the address electrode 22 is formed and the separation wall 20 by the screen printing method.
Afterward, the fabrication of the three electrodes alternating current surface discharge type PDP is completed through the processes shown in FIG. 2.
First, the upper panel and the lower panel are fabricated as shown at step ST1. Second, in an assembling process, seal agent is coated onto the upper panel and the lower panel, and they are temporarily fixed. Afterward, the temporarily fixed upper panel and lower panel are put into a calcining furnace, are heated at about 450° C. as a melting point of the seal agent, and accordingly the upper panel and lower panel are adhered to each other as shown at step ST2. Third, in an exhausting and discharge gas-injecting process, the internal portion of the adhered upper and lower panels is vacuumized, and several mg inert gas as a mixed gas of Ne, Xe, He, etc. is injected therein as shown at step ST3. Last, a panel aging process is performed as shown at step ST4. In the panel aging process, to prevent driving voltage increase and luminous stain phenomenon due to contamination and oxidation, etc. on the surface of the electrodes occurred in the panel fabrication process, the electrode surface (namely, insulating layer) is uniformed so as to get good discharge characteristics and reduce a driving voltage. In addition, the panel aging process is for examining condemned panel in the early stage by applying an appropriate voltage to a panel or securing reliability of a panel through device voltage stabilization, a time required for the panel aging process is about 24 hours.
However, in mass production of the PDP, the panel aging process causes a bottle neck phenomenon in which lots of time and cost are consumed, and accordingly a PDP device production time and cost may increase.
In order to solve the above-mentioned problem, it is an object of the present invention to provide a method for removing impurities of a PDP (plasma display panel) which is capable of reducing a panel aging time by removing impurities on an upper panel and a lower panel under vacuum gas circumstances.
In order to achieve the above-mentioned object, a method for removing impurities of a PDP (plasma display panel) in accordance with the present invention includes fabricating an upper substrate and a lower substrate; and removing impurities of the upper and lower substrates by using at least one of a cleaning process in which discharge is performed under vacuum gas circumstances and a heating process in which heating is performed.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
In the drawings:
As depicted in
The plasma-cleaning unit includes a RF (radio frequency) supply power source 30; a first flat plate electrode 34 installed so as to face the top surface of an upper substrate 36 and contact to the RF power supply source 30; and a second flat plate electrode 40 installed so as to face the bottom surface of a lower substrate 38 and contact to a GND (ground).
The heating unit includes an alternating current power supply source 44; and heaters 32, 42 installed so as to face the top surface of the first flat plate electrode 34 and the bottom surface of the second flat plate electrode 40 respectively and contact the alternating current power supply source 44. Herein, the heaters 32, 42 are for heating the upper substrate 36 and the lower substrate 38.
Hereinafter, a method for removing impurities of a PDP (plasma display panel) in accordance with the present invention will be described.
As depicted in
The method for removing impurities of the PDP (plasma display panel) will be described in more detail.
Because the upper and lower substrates 36, 38 are fabricated by the same process with the conventional art, detailed description about that will be abridged.
After fabricating the upper and lower substrates 36, 38 as shown at step ST10, the process of removing impurities of the upper and lower substrates by using at least one of a plasma-cleaning process or a heating process is performed.
In order to perform the cleaning process, the RF plower supply source 30 supplies a radio frequency in MHz and preferably, 13.56 MHz to the first flat plate electrode 34. Accordingly, plasma discharge occurs under inert gas circumstances between the upper substrate 36 installed on the first flat plate electrode 34 and the lower substrate 38 installed on the second flat plate electrode 40. According to that, a protecting film of the upper substrate 36 and the surface of a fluorescent material of the lower substrate 38 are appropriately cleaned by positive ions of gas.
Afterward, in order to perform the heating process, the alternating current power supply source 44 supplies alternating current to the heaters 32, 42, each heater 32, 42 heats the upper and lower substrates 36, 38 in vacuum respectively, and accordingly impurities are removed. Herein, the heating process can be simultaneously performed with the plasma-cleaning process in order to remove impurities more efficiently, improve a reaction speed, improve flatness and maintain a uniformity, etc. of the substrates or only the heating process can be performed for the above-mentioned effects.
The plasma-cleaning process and heating process of the cleaning process are performed under conditions shown in Table 1.
As depicted in
As depicted in
Afterward, the upper and lower substrates 36, 38 cleaned through the plasma-cleaning process and/or the heating process are assembled.
In the assembling process, positions of the seal agent coated-upper substrate 36 and the lower substrate 38 are fixed, and they are assembled temporarily. Herein, the positions are determined in the accuracy, flatness and parallelism aspects by an image processing technique. Afterward, the temporarily assembled upper and lower substrates 36, 38 are put into a calcining furnace, are heated at about 450° C. as a melting point of the seal agent, and accordingly the upper and lower substrates 36, 38 are adhered to each other.
In an exhausting and discharge gas injecting process, the inner portion of the adhered upper and lower substrates 36, 38 is vacuumized, and several mg of an inert gas as a mixed gas of Ne, Xe, He, etc. is injected therein.
Last, a panel aging process is performed by applying a certain frequency to the electrodes of the upper and lower substrates 36, 38 and generating discharge.
In comparison with the conventional art,
As depicted in
As described above, in the present invention, impurities on the upper and lower substrates can be removed by performing at least one of the plasma-cleaning process in which discharge is performed under vacuum gas circumstances and the heating process in which heating is performed, and accordingly it is possible to reduce a panel aging time. According to that, a production time and cost of a PDP device can be reduced.
As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.
| Number | Date | Country | Kind |
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