Embodiments relate to a plasma display panel and a method of manufacturing the same.
A plasma display panel includes a phosphor layer inside discharge cells partitioned by barrier ribs and a plurality of electrodes.
When driving signals are applied to the electrodes of the plasma display panel, a discharge occurs inside the discharge cells. More specifically, when the discharge occurs in the discharge cells by applying the driving signals to the electrodes, a discharge gas filled in the discharge cells generates vacuum ultraviolet rays, which thereby cause phosphors between the barrier ribs to emit visible light. An image is displayed on the screen of the plasma display panel using the visible light.
As shown in
An upper dielectric layer 104 may be formed on the scan electrode 102 and the sustain electrode 103 to limit a discharge current of the scan electrode 102 and the sustain electrode 103 and to provide insulation between the scan electrode 102 and the sustain electrode 103.
A protective layer 105 may be formed on the upper dielectric layer 104 to facilitate discharge conditions. The protective layer 105 may be formed of a material having a high secondary electron emission coefficient, for example, magnesium oxide (MgO).
A lower dielectric layer 115 may be formed on the address electrode 113 to provide insulation between the address electrodes 113.
Barrier ribs 112 of a stripe type, a well type, a delta type, a honeycomb type, etc. may be formed on the lower dielectric layer 115 to partition discharge spaces (i.e., discharge cells). Hence, a first discharge cell emitting red light, a second discharge cell emitting blue light, and a third discharge cell emitting green light, etc. may be formed between the front substrate 101 and the rear substrate 111.
The barrier rib 112 may include first and second barrier ribs 112a and 112b crossing each other. Heights of the first and second barrier ribs 112a and 112b may be different from each other. The first barrier rib 112a may be substantially parallel to the scan electrode 102 and the sustain electrode 103, and the second barrier rib 112b may be substantially parallel to the address electrode 113.
The height of the first barrier rib 112a may be less than the height of the second barrier rib 112b. Hence, in an exhaust process and a process for injecting a discharge gas, an impurity gas in the panel 100 may be efficiently exhausted to the outside of the panel 100, and the discharge gas may be uniformly injected. Each of the discharge cells partitioned by the barrier ribs 112 may be filled with the discharge gas.
A phosphor layer 114 may be formed inside the discharge cells to emit visible light for an image display during an address discharge. For example, first, second, and third phosphor layers that respectively generate red, blue, and green light may be formed inside the discharge cells.
While the address electrode 113 may have a substantially constant width or thickness, a width or thickness of the address electrode 113 inside the discharge cell may be different from a width or thickness of the address electrode 113 outside the discharge cell. For example, a width or thickness of the address electrode 113 inside the discharge cell may be greater than a width or thickness of the address electrode 113 outside the discharge cell.
The bus electrodes 102b and 103b may be formed of an opaque material, for example, at least one of silver (Ag), gold (Au) and aluminum (Al). The transparent electrodes 102a and 103a may be formed of a transparent material, for example, indium-tin-oxide (ITO).
When the scan electrode 102 and the sustain electrode 103 each include the transparent electrodes 102a and 103a and the bus electrodes 102b and 103b, black layers 120 and 130 may be formed between the transparent electrodes 102a and 103a and the bus electrodes 102b and 103b so that external light is prevented from being reflected by the bus electrodes 102b and 103b.
The transparent electrodes 102a and 103a may be omitted in the scan electrode 102 and the sustain electrode 103. The scan electrode 102 and the sustain electrode 103, in which the transparent electrode is omitted, may be referred to as an ITO-less electrode.
As shown in
More specifically, the rising signal RS may be supplied to the scan electrode Y during a setup period SU of the reset period RP, and the falling signal FS may be supplied to the scan electrode Y during a set-down period SD following the setup period SU. The rising signal RS may generate a weak dark discharge (i.e., a setup discharge) inside the discharge cells. Hence, the remaining wall charges may be uniformly distributed inside the discharge cells. The falling signal FS may generate a weak erase discharge (i.e., a set-down discharge) inside the discharge cells. Hence, the remaining wall charges may be uniformly distributed inside the discharge cells to the extent that an address discharge occurs stably.
During an address period AP following the reset period RP, a scan bias signal Vsc having a voltage greater than a minimum voltage of the falling signal FS may be supplied to the scan electrode Y. A scan signal Scan falling from the scan bias signal Vsc may be supplied to the scan electrode Y during the address period AP.
A pulse width of a scan signal supplied to the scan electrode during an address period of at least one subfield of a frame may be different from pulse widths of scan signals supplied during address periods of other subfields of the frame. A pulse width of a scan signal in a subfield may be greater than a pulse width of a scan signal in a next subfield. For example, a pulse width of the scan signal may be gradually reduced in the order of 2.6 μs, 2.3 μs, 2.1 μs, 1.9 μs, etc. or may be reduced in the order of 2.6 μs, 2.3 μs, 2.3 μs, 2.1 μs . . . 1.9 μs, 1.9 μs, etc. in the successively arranged subfields.
When the scan signal Scan is supplied to the scan electrode Y, a data signal Data corresponding to the scan signal Scan may be supplied to the address electrode X. As the voltage difference between the scan signal Scan and the data signal Data is added to a wall voltage resulting from the wall charges produced during the reset period RP, an address discharge may occur inside the discharge cells to which the data signal Data is supplied.
During a sustain period SP following the address period AP, a sustain signal SUS may be supplied to at least one of the scan electrode Y or the sustain electrode Z.
As shown in
In
The first area 310 may be a middle portion of the substrate 101, and the second area 320 may be an edge portion of the substrate 101. Namely, the first area 310 may be positioned between at least two second areas 320.
In a cross-sectional view taken along a direction crossing a longitudinal direction of the first and second electrodes 301 and 302 (i.e., a cross-sectional view taken along a dotted line A of
When the cross-sectional area S1 of the first electrode 301 is smaller than the cross-sectional area S2 of the second electrode 302, generation of an erroneous discharge in the second area 320 may be suppressed.
The cross-sectional shape of the first electrode 301 may be a convex shape, and the cross-sectional shape of the second electrode 302 may be a polygon.
As shown in
The driving device 520 may be positioned in the rear of a heat dissipation frame (not shown) positioned in the rear of the plasma display panel. The driving device 520 may be positioned at a location corresponding to a central portion of the panel. Therefore, a distance between the second electrode 302 and the driving device 520 may be greater than a distance between the first electrode 301 and the driving device 520. This may mean that a length of a second transmission line 500 electrically connecting the second electrode 302 to the driving device 520 is longer than a length of a first transmission line 510 electrically connecting the first electrode 301 to the driving device 520. Accordingly, an electrical resistance of the second transmission line 500 for supplying a driving signal to the second electrode 302 may be greater than an electrical resistance of the first transmission line 510 for supplying a driving signal to the first electrode 301. Hence, a voltage drop resulting from the second transmission line 500 may cause an erroneous discharge. More specifically, an intensity of a discharge generated in the second area 320 including the second electrode 302 may become excessively weaker by a voltage drop resulting from the second transmission line 500. For example, even if a driving signal is supplied to the second electrode 302, a discharge does not occur in the second area 320.
Furthermore, in case a temperature of the plasma display panel is higher than a normal temperature, an amount of wall charges may be insufficient because of a re-combination between wall charges inside the discharge cells. Hence, a discharge cell of the second area 320 to be turned on is turned off because of the voltage drop resulting from the second transmission line 500.
A luminance of an image displayed in the second area 320 including the second electrode 302 may be smaller than a luminance of an image displayed in the first area 310 including the first electrode 301 because of the voltage drop resulting from the second transmission line 500. In other words, the image quality may worsen because of a difference between the luminances of the image.
On the other hand, as shown in
As shown in
As shown in
As described above, if the thickness t4 of the edge portion 710 of the second electrode 302 is greater than the thickness t2 of the edge portion 610 of the first electrode 301 in a state where the thickness t3 of the middle portion 700 of the second electrode 302 is substantially equal to the thickness t1 of the middle portion 600 of the first electrode 301 and the width W1 of the cross section of the first electrode 301 is substantially equal to the width W2 of the cross section of the second electrode 302, the cross-sectional area of the second electrode 302 may be greater than the cross-sectional area of the first electrode 301.
If the width W1 of the cross section of the first electrode 301 is different from the width W2 of the cross section of the second electrode 302, a viewer may perceive as if a stripped pattern is formed in a boundary portion between the first electrode 301 and the second electrode 302. Hence, the image quality may worsen.
A shown in
The first and second electrodes 801 and 802 may be the same kind of electrode. Preferably, the first and second electrodes 801 and 802 may be address electrodes.
The cross-sectional shape of the first electrode 801 may be convex. The first electrode 801 may have the same characteristics as the first electrode illustrated in
In
In
In
In
Further, each of the second areas 320, 820 and 1220 may overlap an active area as well as the dummy area. More specifically, the second electrodes 302 and 802, whose the cross-sectional areas are greater than the cross-sectional areas of the first electrodes 301 and 801, may be positioned in the active area as well as the dummy area under condition that the generation of erroneous discharge in an edge portion of the plasma display panel is suppressed.
The second areas 320, 820 and 1220 may correspond to a dummy area, and the first areas 310, 810 and 1210 may correspond to an active area.
As shown in
In the fully printing method, the electrode material may be coated on the whole of a predetermined area. In the selectively printing method, the electrode material may be coated on a selected area and may not be coated on a non-selected area.
For example, as shown in
The 10th area 1401 may be a formation area of the first electrode, and the 20th area 1402 may be an area between the two first electrodes.
In the fully printing method, the electrode material may be coated on a screen mask, and then the electrode material on the screen mask may be printed on the substrate 1400 using a squeezer.
In the selectively printing method, a direct printing method such as an offset method may be used.
Further, the screen mask may be changed in conformity with the shape of the first electrode, and then the selectively printing method may be performed using the changed screen mask.
Through the above-described methods, the electrode material may be selectively printed on the first area 1420 in conformity with the shape of the first electrode, and the electrode material may be entirely printed on the second area 1430.
In the process for printing the electrode material 1410, because the electrode material 1410 is selectively printed on the first area 1420, an amount of electrode material used may be reduced. Hence, the manufacturing cost of the panel may be reduced.
After the process for printing the electrode material 1410 is performed, the electrode material 1410 printed on the first and second areas 1420 and 1430 may be exposed.
For example, as shown in
Because the electrode material 1410 in the first area 1420 is printed in conformity with the shape of the first electrode in the printing process, a photomask for the exposure does not need to have a pattern agreeable to the shape of the first electrode. On the other hand, the photomask may have a pattern agreeable to the shape of the first electrode so as to increase precision of the shape of the first electrode, and thus it is possible to expose the electrode material 1410 in the first area 1420 in conformity with the shape of the first electrode.
An exposure area and a printing area are shown in
After the exposure process is performed, the electrode material printed on the first and second areas 1420 and 1430 is developed. Hence, as shown in
After the development process is performed, as shown in
The convex-shaped first electrode 1600 is formed in the first area 1420 using the selectively printing method. Because the first electrode 1600 has the convex shape, a cross-sectional area of the second electrode 1610 may be greater than a cross-sectional area of the first electrode 1600.
When a width W10 of a cross section of the first electrode 1600 is greater than a width W20 of a cross section of the second electrode 1610, an edge portion of the electrode material printed on the 10th area 1401 may be partially etched in the development process. For example, as shown in
It may be preferable that a percentage of an area of the second area based on a total area of the substrate is set at a predetermined value. The second area may correspond to at least one of the second areas shown in
The following Table 1 indicates when a percentage of an area P2 of the second area based on a total area P of the substrate changes from 1% to 50%, whether or not an erroneous discharge occurs and an amount of electrode material used. Silver (Ag) was used as the electrode material.
The erroneous discharge indicated in Table 1 may mean an erroneous discharge resulting from a phenomenon in which a cell to be turned on is turned off in a state where a predetermined image is displayed on the screen of the panel at a high temperature. A large number of observers observed the off-phenomenon of the cell to be turned on in a dark room to evaluate a state of the erroneous discharge.
In the following Table 1, X, ◯, and ⊚ represent bad, good, and excellent states of the characteristics, respectively. More specifically, in an erroneous discharge resulting from an off-phenomenon of a cell to be turned on at a high temperature, X represents that the erroneous discharge excessively occurs, and ⊚ represents that the erroneous discharge is completely prevented. In an amount of Ag used, X represents that a large amount of Ag is used, and ⊚ represents that the amount of Ag used is greatly reduced.
Table 1
When a percentage of the area P2 of the second area based on the total area P of the substrate is 1%, the erroneous discharge may excessively occur. In this case, because the area P2 of the second area may be excessively small, it is difficult to prevent the erroneous discharge from being generated at an edge of the plasma display panel.
When a percentage of the area P2 of the second area based on the total area P of the substrate is 5% to 50%, the erroneous discharge may be completely prevented. In this case, because the area P2 of the second area may be sufficiently large, electrical resistances of the electrodes positioned an edge of the plasma display panel may be sufficiently reduced. Hence, the erroneous discharge may be prevented from being generated at the edge of the plasma display panel.
When a percentage of the area P2 of the second area based on the total area P of the substrate is 3%, the erroneous discharge may be properly prevented. In this case, the erroneous discharge may be generated at the edge of the plasma display panel. However, an influence of the erroneous discharge on the image quality of the plasma display panel may be negligible.
When a percentage of the area P2 of the second area based on the total area P of the substrate is 30% to 50%, the area P2 of the second area may be excessively large. Hence, because the amount of Ag used increases, the manufacturing cost may rise.
When a percentage of the area P2 of the second area based on the total area P of the substrate is 1% to 20%, the area P2 of the second area may be sufficiently small. Hence, because the amount of Ag used is sufficiently reduced, the manufacturing cost may fall.
When a percentage of the area P2 of the second area based on the total area P of the substrate is 25%, the amount of Ag used may be proper.
Considering the above Table 1, a percentage of the area P2 of the second area based on the total area P of the substrate may be 3% to 25% or 5% to 20%.
Number | Date | Country | Kind |
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10-2008-0097087 | Oct 2008 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/KR2009/000764 | 2/18/2009 | WO | 00 | 3/19/2010 |