This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for PLASMA DISPLAY PANEL COMPRISING A BACK PANEL AND MANUFACTURING METHOD OF THE BACK PANEL OF PLASMA DISPLAY PANEL earlier filed in the Korean Intellectual Property Office on 9 Oct. 2003 and there duly assigned Serial No. 2003-70284.
1. Field of the Invention
The present invention relates to a Plasma Display Panel (PDP) and a method of manufacturing a back panel of the PDP, and more particularly, to a PDP that forms an image by applying a discharge voltage to a plurality of electrodes arranged on two substrates facing each other to generate ultraviolet rays which excite phosphor layers and a method of manufacturing the back panel.
2. Description of the Related Art
Plasma display panels (PDPs) can be classified into Direct Current (DC) PDPs and Alternating Current (AC) PDPs. In the DC PDP, electrodes are exposed in a discharging space, and charged particles move directly between the corresponding electrodes. In the AC PDP, at least one electrode is covered by a dielectric layer, and a discharge occurs using an electric field of a wall charge instead of a charge directly moving between the electrodes.
An AC PDP includes a front panel and a back panel. The front panel includes a front plate. X electrodes and Y electrodes are arranged in pairs on the front plate, and address electrodes crossing the X and Y electrodes are arranged on a surface of a back plate facing the front plate. The X and Y electrodes on the front plate are transparent electrodes made of Indium-Tin-Oxide (ITO), and are also referred to as transparent electrodes. In addition, bus electrodes, which are formed of metal and have narrow widths for reducing line resistance, are arranged on an upper portion of the transparent electrodes. A discharge space forming a unit discharge cell is defined by a pair of X and Y electrodes and the address electrode crossing the pair of X and Y electrodes.
A front dielectric layer and a back dielectric layer are arranged on the front plate where the X and Y electrodes are arranged and on the surface of the back plate where the address electrodes are arranged to cover the electrodes. A protective layer is arranged on the front dielectric layer, and a barrier rib that maintains a discharge distance and prevents cross-talk between discharge cells is arranged on the back dielectric layer. Red, green, and blue phosphor layers are arranged on both surfaces of the barrier rib and an upper surface of the back dielectric layer where the barrier rib is not formed. The front panel and the back panel are sealed by a sealing unit, for example, a frit.
When a discharge cell is selected for emitting light, a predetermined voltage is applied to the address electrode and the Y electrode of the selected discharge cell. Then, an address discharge. occurs and a wall charge is generated on the front dielectric layer. When a predetermined voltage is applied between the X electrode and the Y electrode, the wall charge moves between the two electrodes to cause the discharge gas to undergo a sustaining discharge and to generate ultraviolet rays. Then, the ultraviolet rays excite the phosphor layer to form an image.
A PDP can be divided into an image area H that can display an image and a non-image area N that cannot display an image. On the image area H, the address electrodes, the X electrodes, and the Y electrodes are connected to a driving circuit that drives the address electrodes and the X and Y electrodes, and accordingly, the image can be displayed in response to signals from the driving circuit. On the non-image area N, at least one of the address electrode, the X electrode, and the Y electrode is not connected to the driving circuit so that an image cannot be displayed there. The back panel 30 includes a back plate terminal area C, on which the address electrodes are connected to a driving unit that drives the address electrodes.
A ventilation hole is arranged in the non-image area N.
The ventilation hole, coupled with a ventilation pipe that is arranged on a back surface of the back plate, simultaneously serves as a path through which gas remaining in an outer part of the PDP can be discharged after joining the front plate and the back plate, and as a path through which the remaining gas that is generated in fabricating the front plate and the back plate and joining the plates can be exhausted to the ventilation pipe and a gas, such as Ne or Xe, can enter the PDP. Thus, the ventilation hole, together with the ventilation pipe, performs both a vacuum induction role and a gas path role.
However, the ventilation hole of the PDP is formed by a hole forming unit, such as a drill, from the upper surface of the back panel 30 to the lower surface, or in the opposite direction. Thus, when the operation of forming the hole in the back plate is completed, the back plate becomes more vulnerable to damage. Specifically, the surface of the back plate becomes rough, and the area around the ventilation hole is prone to cracking.
In addition, only one back plate is fabricated from a base plate and a remaining portion of the base plate that is not included in the back plate is discarded. This increases manufacturing overhead of the back plate.
In order to solve the above problem, recently, one base plate is cut to manufacture a plurality of back plates. Thus, the excluded portion of the base plate can be reduced, and the manufacturing cost of the back plate can be reduced.
However, when the ventilation hole is not distanced from the cut by more than a predetermined threshold length, the area around the ventilation hole is even more prone to cracking, and the back plate can be damaged. Specifically, since an end portion of the back plate is coupled to a jig during manufacture and handling, stress is applied to the crack, and the back plate can be damaged more.
The present invention provides a Plasma Display Panel (PDP), which includes a back plate having a structure that prevents cracking around a ventilation hole and damage to a periphery of the ventilation hole caused by a jig used to move the back plate, and a method of manufacturing the back panel of the plasma display panel.
According to an aspect of the present invention, a plasma display panel is provided comprising: a front panel including a front plate; a plurality of electrodes arranged on a surface of the front plate in a predetermined pattern; a back panel including a back plate facing the front plate; a plurality of electrodes arranged on a surface of the back plate in a predetermined pattern to correspond to the plurality of electrodes of the front plate; and at least one ventilation hole having a first width in a first edge direction of the back plate and a distance from the first edge to a center of the at least one ventilation hole being at least twice that of the first width.
The distance from the first edge of the back plate to the center of the at least one ventilation hole is preferably at least 2.3 times that of the first width.
The at least one ventilation hole has a second width in a direction of a second edge that intersects the first edge, and a distance from the second edge to the center of the at least one ventilation hole is preferably at least 1.1 times that of the second width.
The distance from the second edge to the center of the at least one ventilation hole is preferably at least 1.23 times that of the second width.
The at least one ventilation hole preferably has a circular shape.
According to another aspect of the present invention, a plasma display panel is provided comprising: a front panel including a front plate and a plurality of electrodes arranged on a surface of the front plate in a predetermined pattern; and a back panel including a back plate facing the front plate, a plurality of electrodes arranged on a surface of the back plate in a predetermined pattern to correspond to the plurality of electrodes of the front plate, and at least one ventilation hole; wherein the at least one ventilation hole has a first width in a direction of a first edge of the back plate, on which a back plate driving terminal unit is arranged, and wherein a distance from the first edge to a center of the at least one ventilation hole is at least twice that of the first width.
The distance from the first edge to the center of the at least one ventilation hole is preferably at least 2.3 times that of the first width.
The at least one ventilation hole has a second width in a direction of a second edge of the back plate that intersects the first edge, and a distance from the second edge to the center of the at least one ventilation hole is preferably at least 1.1 times that of the second width.
The distance from the second edge to the center of the at least one ventilation hole is preferably at least 1.23 times that of the second width.
The at least one ventilation hole preferably has a circular shape.
According to still another aspect of the present invention, a method of manufacturing a back panel in a plasma display panel is provided, the method comprising: forming a plurality of electrodes on a base plate that includes a plurality of back plates; forming at least one ventilation hole on each back plate by drilling into the back plate from corresponding positions on upper and lower surfaces of the back plate; and cutting the base plate into at least two back plates.
In forming at least one ventilation hole on each back plate, the at least one ventilation hole which has a first width in a direction of a first edge of the back plate is formed so that a distance from the first edge to the center of the at least one ventilation hole is preferably at least twice that of the first width.
The at least one ventilation hole is formed so that the distance from the first edge to the center of the at least one ventilation hole is preferably at least 2.3 times that of the first width.
In forming at least one ventilation hole on each back plate, the at least one ventilation hole which has a second width in a direction of a second edge of the back plate crossing the first edge is formed so that a distance from the second edge to the center of the at least one ventilation hole is preferably at least 1.1 times that of the second width.
The distance from the second edge to the center of the at least one ventilation hole is preferably at least 1.23 times that of the second width.
A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein:
As shown in
A front dielectric layer 26 and a back dielectric layer 36 are arranged on the front plate 22 where the X and Y electrodes 23 and 24 are arranged and on the surface of the back plate 32 where the address electrodes 35 are arranged, so that the electrodes are covered. A protective layer 27 is arranged on the front dielectric layer 26, and a barrier rib 37, that maintains a discharge distance and prevents cross-talk between discharge cells, is arranged on the back dielectric layer 36. Red, green, and blue phosphor layers 38 are arranged on both surfaces of the barrier rib 37 and an upper surface of the back dielectric layer 36 where the barrier rib 37 is not formed. The front panel 20 and the back panel 30 are sealed by a sealing unit 40, for example, a frit.
When a discharge cell is selected for emitting light, a predetermined voltage is applied to the address electrode 35 and the Y electrode 24 of the selected discharge cell. Then, an address discharge occurs and a wall charge is generated on the front dielectric layer 26. When a predetermined voltage is applied between the X electrode 23 and the Y electrode 24, the wall charge moves between the two electrodes 23 and 24 to cause the discharge gas to undergo a sustaining discharge and to generate ultraviolet rays. Then, the ultraviolet rays excite the phosphor layer 38 to form an image.
Referring to
A ventilation hole 50 is arranged in the non-image area N.
The ventilation hole 50, coupled with a ventilation pipe that is mounted on a back surface of the back plate, simultaneously serves as a path through which gas remaining in an outer part of the PDP can be discharged after joining the front plate to the back plate, and as a path through which the remaining gas, generated in fabricating the front plate and the back plate and joining the plates, can be exhausted to the ventilation pipe and a gas, such as Ne or Xe, can enter the PDP. Thus, the ventilation hole 50, together with the ventilation pipe, performs both a vacuum induction role and a gas path role.
The ventilation hole 50 of the PDP is formed by a hole forming unit such as a drill from the upper surface of the back panel 30 to the lower surface, or in the opposite direction. After the operation of forming the hole in the back plate has been completed, the back plate becomes more vulnerable to damage. Specifically, the surface of the back plate becomes rough, and the area around the ventilation hole is prone to cracking.
In addition, only one back plate is fabricated from a base plate and a remaining portion of the base plate that is not included in the back plate is discarded. This increases the manufacturing cost of the back plate.
In order to solve the above problem, recently, one base plate has been cut to manufacture a plurality of back plates 32. This reduces both the discarded portion of the base plate and the manufacturing cost of the back plate 32.
However, when the ventilation hole 50 is not distanced from the cut by more than a predetermined threshold length, the area around the ventilation hole 50 is even more prone to cracking, and the back plate 32 can be damaged. Specifically, since an end portion of the back plate 32 is coupled to a jig during manufacture and since stress is applied and the back plate can be damaged.
Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, whenever the same element reappears in a subsequent drawing, it is denoted by the same reference numeral.
Referring to
The plurality of electrodes 23, 24, and 25 are arranged in predetermined patterns, for example, a stripe pattern or a zigzag pattern. If the PDP 100 according to the first embodiment of the present invention is an AC PDP, a front dielectric layer 26 can be arranged on the front plate 22 and a protective layer 27 is arranged on the front dielectric layer 26, as shown in
A plurality of address electrodes 135 are arranged on a surface of the back plate 132. The plurality of electrodes 135 on the back plate 132 are arranged in a predetermined pattern, for example, a stripe pattern or a zigzag pattern, to correspond to the electrodes 23, 24, and 25 arranged on the front plate 22. The front panel 120 and the back panel 130 are sealed together using a sealing unit 140, for example, a frit.
The at least one ventilation hole 150 is formed after arranging the address electrodes 135, the back dielectric layer 136, the barrier rib 137, and the phosphor layer 138 on the side of the back plate 132. The at least one ventilation hole 150 is used to remove gas remaining between the back plate 132 and the front plate 22 in order to maintain a vacuum state, and to induce a gas, such as Xe or Ne, into the PDP 100 in order to facilitate a discharge. In
As shown in
It is desirable that a distance L1 from the first edge 133 to the center of the ventilation hole 150 be at least twice that of the first width D1. For example, if D1 is 7.5 mm, it is desirable that L1 is at least 15 mm.
As shown in the graph of
As shown in
Also, the ventilation hole 150 has the second width D2 in the direction of the second edge 134, which encounters the first edge 133 at a comer. It is desirable that a distance L2 from the second edge 134 to the center of the ventilation hole is at least 1.1 times the length of D2. For example, if D2 is 7.3 mm, it is desirable that L2 is at least 8 mm.
As shown in
Thus, it is most desirable that the value of L2/D2 be at least 1.23.
It is desirable for the ventilation hole to be circular, since a circular cross section occupies less space and more gas can pass through a circular hole. Also, the ventilation hole corresponds to a ventilation pipe (not shown) that generally has a circular cross section.
Referring to
The ventilation hole 250 is formed after forming the plurality of electrodes 235, a back dielectric layer 236, a barrier rib 237, and a phosphor layer 238 on a surface of the back plate 232. In addition, the front panel 220, on which the front plate 22 and the electrodes 23, 24, and 25 are arranged, and the plurality of electrodes 235, the back dielectric layer 236, the barrier rib 237, the phosphor layer 238, and the sealing unit 240 arranged on the back plate 232, are all the same as those of the front panel 120 included in the PDP 100 according to the first embodiment of the present invention, and accordingly, detailed descriptions thereof have been omitted for the sake of brevity.
As shown in
The ventilation hole 250 has a first width D1 in the direction of the first edge 233, and it is desirable that a distance L1 from the first edge 233 to the center of the ventilation hole 250 be at least twice that of the first width D1. For example, if D1 is 7.5 mm, it is desirable that L1 is at least 15 mm. This is because when the value of L1/D1 increases, the defect rate of the back panel gradually decreases, and when L1/D1 approaches 2, the defect rate of the back panel is greatly reduced. Furthermore, when L1/D1 exceeds 2.3, the back panel defect rate is 0. Thus, it is most desirable that L1/D1 be at least 2.3.
Also, the back plate 232 has the second edge 234 that intersects the first edge 233, and the ventilation hole 250 has a second width D2 in the direction of the second edge 234. In addition, it is desirable that the distance L2 from the second edge 234 to the center of the ventilation hole 250 is at least 1.1 times that of the second width D2. For example, if D2 is 7.3 mm, it is desirable that L2 be at least 8 mm.
As shown in
It is desirable for the ventilation hole 250 to be circular so that the ventilation hole 250 occupies less space and a larger amount of gas can pass through it. In addition, the ventilation hole 250 corresponds to a ventilation pipe (not shown) that generally has a circular cross section.
First, the plurality of electrodes 135, that is, the address electrodes, are arranged on the surface of the base plate 131. As shown in the drawings, if the PDP is an AC PDP, the above step includes forming the back dielectric layer 136, the barrier rib 137, and the phosphor layer 138 on the plurality of electrodes 135. In the second step, the back plate 132 is drilled from corresponding positions A and B on the upper and lower surfaces so that the ventilation hole 150 can be formed with minimum damage due to drilling on either side of the back plate 132. Accordingly, the operation of forming the ventilation hole is completed inside the back plate 132 rather than on the surface of the back plate 132. Thus, cracks or irregularities are not generated on the surface around the ventilation hole 150, and the ventilation hole 150 can be easily coupled to the ventilation pipe (not shown).
Thus, it is desirable that the ventilation hole 150 be formed so that L1 is at least twice as long than D1, as shown in
Also, as shown in
In the third step, the base plate 131 is cut to form a plurality of back panels 130.
According to the present invention, the size of the ventilation hole and separation distance from an edge of the back plate, which is formed by cutting one substrate including at least two ventilation holes, can be applied quantitatively to prevent damage around the ventilation hole during moving the back panel or during a jig process. Thus, the defect rate of the PDP can be reduced.
Also, since the hole forming process is completed inside the back plate, cracking around the ventilation hole can be prevented and the ventilation hole can be coupled to the ventilation pipe easily.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details can be made therein without departing from the spirit and scope of the present invention as recited by the following claims.
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