This application claims the benefit of Korean Patent Application No. 10-2006-0104715 filed on Oct. 26, 2006, which is hereby incorporated by reference.
1. Field of the Disclosure
This document relates to a plasma display panel.
2. Description of the Related Art
A plasma display panel includes phosphor layers inside discharge cells partitioned by barrier ribs and a plurality of electrodes. Driving signals are supplied to the discharge cells through the electrodes.
When the driving signal generates a discharge inside the discharge cells, a discharge gas filled in the discharge cells generates vacuum ultraviolet rays, which thereby cause phosphors formed inside the discharge cells to emit light, thus displaying an image on the screen of the plasma display panel.
In one aspect, a plasma display panel comprises a front substrate on which a first electrode and a second electrode are positioned parallel to each other, a rear substrate on which a third electrode is positioned to intersect the first electrode and the second electrode, and a barrier rib positioned between the front substrate and the rear substrate to partition a discharge cell, wherein at least one of the first electrode or the second electrode has a single-layered structure, at least one of the first electrode or the second electrode includes a plurality of line portions intersecting the third electrode, a projecting portion projecting from the line portion, and a connecting portion connecting at least two line portions of the plurality of line portions to each other, and the projecting portion and the connecting portion are positioned in a straight line.
In another aspect, a plasma display panel comprises a front substrate on which a first electrode and a second electrode are positioned parallel to each other, a rear substrate on which a third electrode is positioned to intersect the first electrode and the second electrode, and a barrier rib positioned between the front substrate and the rear substrate to partition a discharge cell, wherein at least one of the first electrode or the second electrode has a single-layered structure, at least one of the first electrode or the second electrode includes a plurality of line portions intersecting the third electrode, a plurality of projecting portions projecting from the line portion, and a plurality of connecting portions connecting at least two line portions of the plurality of line portions to each other, the projecting portion and the connecting portion are positioned in a straight line, and an interval between two successively positioned line portions of the plurality of line portions is larger than an interval between two successively positioned connecting portions of the plurality of connecting portions.
In still another aspect, a plasma display panel comprises a front substrate on which a first electrode and a second electrode are positioned parallel to each other, a rear substrate on which a third electrode is positioned to intersect the first electrode and the second electrode, and a barrier rib positioned between the front substrate and the rear substrate to partition a discharge cell, wherein at least one of the first electrode or the second electrode has a single-layered structure, at least one of the first electrode or the second electrode includes a plurality of line portions intersecting the third electrode, a projecting portion projecting from the line portion, and a connecting portion connecting at least two line portions of the plurality of line portions to each other, the projecting portion and the connecting portion are positioned in a straight line, and a first signal with a gradually falling voltage is supplied to the first electrode and a second signal of a polarity direction opposite a polarity direction of the first signal is supplied to the second electrode during a pre-reset period prior to a reset period of at least one subfield of a frame.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated on 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:
Reference will now be made in detail embodiments of the invention examples of which are illustrated in the accompanying drawings.
As illustrated in
At least one of the first electrode 102 or the second electrode 103 has a single-layered structure. For instance, at least one of the first electrode 102 or the second electrode 103 may be a bus electrode or ITO (indium-tin-oxide)-less electrode in which a transparent electrode is omitted.
At least one of the first electrode 102 or the second electrode 103 includes an opaque metal with excellent electrical conductivity. Examples of the opaque metal with excellent electrical conductivity include silver (Ag), copper (Cu), and aluminum (Al) that are cheaper than ITO.
The first electrode 102 and the second electrode 103 generate a discharge inside discharge spaces (i.e., discharge cells) and maintain the discharge of the discharge cells.
An upper dielectric layer 104 for covering the first electrode 102 and the second electrode 103 is positioned on the front substrate 101 on which the first electrode 102 and the second electrode 103 are positioned. The upper dielectric layer 104 limits discharge currents of the first electrode 102 and the second electrode 103 and provides insulation between the first electrode 102 and the second electrode 103.
A protective layer 105 is positioned on the upper dielectric layer 104 to facilitate discharge conditions. The protective layer 105 may be formed by deposition a material such as magnesium oxide (MgO) on the upper dielectric layer 104.
A lower dielectric layer 115 for covering the third electrode 113 is positioned on the rear substrate 111 on which the third electrode 113 is positioned. The lower dielectric layer 115 provides insulation of the third electrode 113.
Barrier ribs 112 of a stripe type, a well type, a delta type, a honeycomb type, and the like, are positioned on the lower dielectric layer 115 to partition discharge spaces (i.e., discharge cells). A red (R) discharge cell, a green (G) discharge cell and a blue (B) discharge cell, and the like, are positioned between the front substrate 101 and the rear substrate 111.
In addition to the red (R), green (G), and blue (B) discharge cells, a white discharge cell or a yellow discharge cell may be further positioned between the front substrate 101 and the rear substrate 111.
The widths of the red (R), green (G), and blue (B) discharge cells may be substantially equal to one another. Further, the width of at least one of the red (R), green (G), or blue (B) discharge cells may be different from the widths of the other discharge cells.
For instance, as illustrated in
The widths of the above-described discharge cells determine the width of a phosphor layer 114 formed inside the discharge cells, which will be described later. For instance, in a case of
The plasma display panel according one embodiment may have various forms of barrier rib structures as well as a structure of the barrier rib 112 illustrated in
In the differential type barrier rib structure, as illustrated in
While the plasma display panel according to one embodiment has been illustrated and described to have the red (R), green (G), and blue (B) discharge cells arranged on the same line, it is possible to arrange them in a different pattern. For instance, a delta type arrangement in which the red (R), green (G), and blue (B) discharge cells are arranged in a triangle shape may be applicable. Further, the discharge cells may have a variety of polygonal shapes such as pentagonal and hexagonal shapes as well as a rectangular shape.
While
Each of the discharge cells partitioned by the barrier ribs 112 is filled with a predetermined discharge gas.
The phosphor layers 114 for emitting visible light for an image display during the generation of an address discharge are positioned inside the discharge cells partitioned by the barrier ribs 112. For instance, red (R), green (G) and blue (B) phosphor layers may be positioned inside the discharge cells.
A white phosphor layer and/or a yellow phosphor layer may be further positioned in addition to the red (R), green (G) and blue (B) phosphor layers.
A thickness of at least one of the phosphor layers 114 formed inside the red (R), green (G) and blue (B) discharge cells may be different from thicknesses of the other phosphor layers. For instance, as illustrated in
In
A black layer (not shown) for absorbing external light may be further positioned on the barrier rib 112 to prevent the reflection of the external light caused by the barrier rib 112.
Further, another black layer (not shown) may be further positioned at a specific position of the front substrate 101 corresponding to the barrier rib 112.
The third electrode 113 positioned on the rear substrate 11 may have a substantially constant width or thickness. Further, a width or thickness of the third electrode 113 inside the discharge cell may be different from a width or thickness of the third electrode 113 outside the discharge cell. For instance, a width or thickness of the third electrode 113 inside the discharge cell may be larger than a width or thickness of the third electrode 113 outside the discharge cell.
As illustrated in (a) of
For instance, the first electrode 210 and the second electrode 220 each include transparent electrodes 210a and 220a and bus electrodes 210b and 220b.
The transparent electrodes 210a and 220a may include a transparent material such as ITO. The bus electrodes 210b and 220b may include a metal material such as silver (Ag).
The transparent electrodes 210a and 220a are formed and then the bus electrodes 210b and 220b are formed to complete the first electrode 210 and the second electrode 220.
As illustrated in (b) of
At least one of the first electrode 102 or the second electrode 103 may include a substantially opaque metal material with excellent electrical conductivity. Examples of the opaque metal with excellent electrical conductivity include silver (Ag), copper (Cu) and aluminum (Al) that are cheaper than ITO. At least one of the first electrode 102 or the second electrode 103 may further include a black material such as carbon (C), cobalt (Co) or ruthenium (Ru).
A process for forming the transparent electrodes 210a and 220a and a process for forming the bus electrodes 210b and 220b are required in (a) of
Further, because an expensive material such as ITO is not used in (b) of
As illustrated in
For instance, when the front substrate 101 directly contacts the first or second electrode 102 or 103, a predetermined area of the front substrate 101 directly contacting the first or second electrode 102 or 103 may change into a yellow-based color. The change of color is called a migration phenomenon. The black layers 300a and 300b prevent the migration phenomenon by preventing the direct contact of the front substrate 101 with the first or second electrode 102 or 103.
The black layers 300a and 300b may include a black material of a dark color, for example, ruthenium (Ru).
Since the black layers 300a and 300b are positioned between the front substrate 101 and the second electrode 103 and between the front substrate 101 and the first electrode 102, respectively, the generation of reflection light can be prevented even if the first and second electrodes 102 and 103 are formed of a material with a high reflectivity.
As illustrated in
The line portions 410a, 410b, 440a and 440b are spaced apart from one another with a predetermined distance therebetween. For instance, the first and second line portions 410a and 410b of the first electrode 430 are spaced apart from each other with a distance d1 therebetween. The first and second line portions 440a and 440b of the second electrode 1460 are spaced apart from each other with a distance d2 therebetween. The distance d1 may be equal to or different from the distance d2.
The line portions 410a, 410b, 440a and 440b each have a predetermined width. For instance, the first and second line portions 410a and 410b of the first electrode 430 have widths Wa and Wb, respectively. The width Wa may be equal to or different from the width Wb.
A shape of the first electrode 430 may be symmetrical or asymmetrical to a shape of the second electrode 460 inside the discharge cell. For instance, while the first electrode 430 may include three line portions, the second electrode 460 may include two line portions.
The number of line portions in the first and second electrodes 430 and 460 may vary. For instance, the first electrode 430 or the second electrode 460 may include 4 or 5 line portions.
At least one of the first electrode 430 or the second electrode 460 may include at least one projecting portion projecting from the line portion. For instance, the first electrode 430 includes two projecting portions 420a and 420b projecting from the line portion 410a, and the second electrode 460 includes two projecting portions 450a and 450b projecting from the line portion 440a.
The projecting portions 420a, 420b, 450a and 450b may project in a direction toward the center of the discharge cell inside the discharge cell.
The projecting portions 420a and 420b of the first electrode 430 may be positioned to face the projecting portions 450a and 450b of the second electrode 460. Hence, an interval g1 between the projecting portions 420a and 420b and the projecting portions 450a and 450b may be smaller than an interval g2 between the first line portion 410a of the first electrode 430 and the first line portion 440a of the second electrode 460.
When a driving signal is supplied to the first electrode 430 and the second electrode 460, a discharge firstly occurs between the projecting portions 420a and 420b of the first electrode 430 and the projecting portions 450a and 450b of the second electrode 460. Then, the discharge is diffused into the first and second line portions 410a and 410b of the first electrode 430 and the first and second line portions 440a and 440b of the second electrode 460.
At least one of the fist electrode 430 or the second electrode 460 includes at least one connecting portion connecting the two or more line portions. For instance, connecting portions 420c and 420d of the first electrode 430 connect the first and second line portions 410a and 410b to each other. Connecting portions 450c and 450d of the second electrode 460 connect the first and second line portions 440a and 440b to each other. The connecting portions 420c, 420d, 450c and 450d allow a discharge generated between the projecting portions 420a, 420b, 450a and 450b to be easily diffused into the rear of the discharge cell partitioned by the barrier rib 400.
At least one of the connecting portions 420c, 420d, 450c and 450d and at least one of the projecting portions 420a, 420b, 450a and 450b may overlap each other in a direction parallel to the third electrode 470. Preferably, at least one of the connecting portions 420c, 420d, 450c and 450d and at least one of the projecting portions 420a, 420b, 450a and 450b may be positioned in a straight line.
For instance, the connecting portion 420c and the projecting portion 420a of the first electrode 430 overlap each other in a direction parallel to the third electrode 470, and the connecting portion 420d and the projecting portion 420b of the first electrode 430 overlap each other in a direction parallel to the third electrode 470.
As illustrated in
In (a) of
Similar to
(c) of
Accordingly, it is preferable that the projecting portion and the connecting portion are positioned in a straight line.
The number of projecting portions and the number of connecting portions of the first and second electrodes may be variously changed. For instance, as illustrated in
Further, a width of at least one of the plurality of line portions 410a, 410b, 440a and 440b may be different from widths of the other line portions. For instance, as illustrated in
Further, as illustrated in
As illustrated in
For instance, the projecting portions 520a, 520b, 550a and 550b may project from the first line portions 510a and 540a in a direction toward the center of a discharge cell partitioned by a barrier rib 500, and the tail portions 520e, 520f, 550e and 550f may project from the second line portions 510b and 540b in a direction opposite the projecting direction of the projecting portions 520a, 520b, 550a and 550b.
As above, because the first electrode 530 and the second electrode 560 each include the tail portions 520e, 520f, 550e and 550f, a discharge generated between the projecting portions 520a, 520b, 550a and 550b can be more widely diffused inside the discharge cell. Hence, a luminance and the driving efficiency can be improved.
The tail portions 520e, 520f, 550e and 550f may be positioned in a straight line with the projecting portions 520a, 520b, 550a and 550b and connecting portions 520c, 520d, 550c and 550d.
For instance, in
In the panel structure of
As illustrated in
For instance, a width of the projecting portions 620a, 620b, 650a and 650b may be set to a width W10, and a width of the tail portions 620e, 620f, 650e and 650f may be set to a width W20 smaller than the width W10.
As above, when the width W10 of the projecting portions 620a, 620b, 650a and 650b is larger than the width W20 of the tail portions 620e, 620f, 650e and 650f, a firing voltage of a discharge generated between a first electrode 630 and a second electrode 660 can be lowered.
As illustrated in
As above, when the width W20 of the projecting portions 620a, 620b, 650a and 650b is smaller than the width W10 of the tail portions 620e, 620f, 650e and 650f, a discharge generated inside the discharge cell can be more widely diffused into the rear of the discharge cell.
As illustrated in
For instance, a length of the projecting portions 720a, 720b, 750a and 750b may be set to a length L1, and a length of the tail portions 720e, 720f, 750e and 750f may be set to a length L2 shorter than the length L1.
As above, when the length L1 of the projecting portions 720a, 720b, 750a and 750b is longer than the length L2 of the tail portions 720e, 720f, 750e and 750f, a firing voltage of a discharge generated between a first electrode 730 and a second electrode 760 can be lowered.
As illustrated in
As above, when the length L2 of the projecting portions 720a, 720b, 750a and 750b is shorter than the length L1 of the tail portions 720e, 720f, 750e and 750f, a discharge generated inside the discharge cell can be more efficiently diffused into the rear of the discharge cell.
Considering that light is mainly generated in an discharge diffusing area inside the discharge cell, the length L1 of the tail portions 720e, 720f, 750e and 750f may be longer than the length L2 of the projecting portions 720a, 720b, 750a and 750b so as to improve a luminance of an image.
As illustrated in
A portion where the projecting portions 820a, 820b, 850a and 850b are adjacent to line portions 810a, 810b, 840a and 840b may include the curvature. Further, a portion where the line portions 810a, 810b, 840a and 840b are adjacent to connecting portions 820c, 820d, 850c and 1850c may include the curvature.
In the panel structure of
In
In
In
On the contrary, in
As illustrated in
Each subfield is subdivided into a reset period for initializing all the cells, an address period for selecting cells to be discharged, and a sustain period for representing gray level in accordance with the number of discharges.
For instance, if an image with 256-level gray scale is to be displayed, a frame, as illustrated in
The number of sustain signals supplied during the sustain period determines gray level weight in each of the subfields. For instance, in such a method of setting gray level weight of a first subfield to 20 and gray level weight of a second subfield to 21, the sustain period increases in a ratio of 2n (where, n=0, 1, 2, 3, 4, 5, 6, 7) in each of the subfields. Since the sustain period varies from one subfield to the next subfield, a specific gray level is achieved by controlling the sustain period which are to be used for discharging each of the selected cells, i.e., the number of sustain discharges that are realized in each of the discharge cells.
The plasma display panel according to the exemplary embodiment uses a plurality of frames to display an image for 1 second. For instance, 60 frames are used to display an image 1 second. In this case, a time width T of one frame may be 1/60 seconds, i.e., 16.67 ms.
In
Further, in
During a pre-reset period prior to a reset period, a first signal with a gradually falling voltage is supplied to a first electrode Y. A second signal corresponding to the first signal is supplied to a second electrode Z. A polarity direction of the second signal is opposite to a polarity direction of the first signal. The second signal is constantly maintained at a voltage Vpz. The voltage Vpz may be substantially equal to a voltage (i.e., a sustain voltage Vs) of a sustain signal (SUS) to be supplied during a sustain period.
As above, when the first signal is supplied to the first electrode Y and the second signal is supplied to the second electrode Z during the pre-reset period, wall charges of a predetermined polarity are accumulated on the first electrode Y, and wall charges of a polarity opposite the polarity of the wall charges accumulated on the first electrode Y are accumulated on the second electrode Z. For instance, wall charges of a positive polarity are accumulated on the first electrode Y, and wall charges of a negative polarity are accumulated on the second electrode Z.
During a reset period, a third signal is supplied to the first electrode Y. The third signal includes a first rising signal and a second rising signal. The first rising signal gradually rises from a second voltage V2 to a third voltage V3 with a first slope, and the second rising signal gradually rises from the third voltage V3 to a fourth voltage V4 with a second slope.
The third signal generates a weak dark discharge (i.e., a setup discharge) inside the discharge cell during a setup period of the reset period, thereby accumulating a proper amount of wall charges inside the discharge cell.
The setup discharge does not occur at a voltage equal to or less than the third voltage V3, and the setup discharge can occur at a voltage equal to or more than the third voltage V3. Therefore, a voltage of the first electrode Y rapidly rises up to the third voltage V3 and then lowly rises. Hence, an excessive increase in a time width of the setup period can be prevented, and a stability of the setup discharge can be improved. Considering this, it is preferable that the second slope is gentler than the first slope.
Wall charges accumulated inside the discharge cells during the pre-reset period can assist the setup discharge generated during the setup period. Accordingly, although a voltage of the third signal is lowered, the stable setup discharge can occur. When the voltage of the third signal is lowered, the intensity of the setup discharge can be reduced and a reduction in the contrast characteristic can be prevented.
As explained in
On the contrary, the operation during the pre-reset period prior to the reset period can prevent a reduction in the contrast characteristic even if the first electrode and the second electrode each have the single-layered structure.
A subfield, which is first arranged in time order in a plurality of subfields of one frame, may include a pre-reset period prior to a reset period so as to obtain sufficient driving time. Or, two or three subfields may include a pre-reset period prior to a reset period.
During a set-down period of the reset period, a fourth signal of a polarity direction opposite a polarity direction of the third signal is supplied to the first electrode Y. The fourth signal gradually falls from a fifth voltage V5 lower than a peak voltage (i.e., the fourth voltage V4) of the third signal to a sixth voltage V6. The fourth signal generates a weak erase discharge (i.e., a set-down discharge) inside the discharge cell. Furthermore, the remaining wall charges are uniform inside the discharge cells to the extent that an address discharge can be stably performed.
During an address period, a scan bias signal, which is maintained at a seventh voltage V7 higher than a lowest voltage (i.e., the sixth voltage V6) of the fourth signal, is supplied to the first electrode Y.
A scan signal (Scan), which falls from the scan bias signal by a scan voltage magnitude ΔVy, is supplied to the first electrode Y.
The width of the scan signal may vary from one subfield to the next subfield. For instance, the width of a scan signal in a subfield may be larger than the width of a scan signal in the next subfield in time order. Further, the 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 in the order of 2.6 μs, 2.3 μs, 2.3 μs, 2.1 μs, 1.9 μs, 1.9 μs, etc.
As above, when the scan signal (Scan) is supplied to the first electrode Y, a data signal (data) corresponding to the scan signal (Scan) is supplied to the third electrode X. The data signal (data) rises from a ground level voltage GND by a data voltage magnitude ΔVd.
As the voltage difference between the scan signal (Scan) and the data signal (data) is added to the wall voltage generated during the reset period, an address discharge is generated within the discharge cell to which the data signal (data) is supplied.
A sustain bias signal is supplied to the second electrode Z during the address period to prevent the generation of the unstable address discharge by interference of the second electrode Z. The sustain bias signal is substantially maintained at a sustain bias voltage Vz which is lower than the sustain voltage Vs and higher than the ground level voltage GND.
During the sustain period, a sustain signal (SUS) is alternately supplied to the first electrode Y and the second electrode Z. As the wall voltage within the discharge cell selected by performing the address discharge is added to the sustain voltage Vs of the sustain signal (SUS), every time the sustain signal (SUS) is supplied, a sustain discharge, i.e., a display discharge occurs between the first electrode Y and the second electrode Z. Accordingly, a predetermined image is displayed on the plasma display panel.
A plurality of sustain signals are supplied during a sustain period of at least one subfield, and a width of at least one of the plurality of sustain signals may be different from widths of the other sustain signals. For instance, a width of the first supplied sustain signal among the plurality of sustain signals may be larger than widths of the other sustain signals. Hence, a sustain discharge can more stably occur.
The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the foregoing embodiments is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.
Number | Date | Country | Kind |
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10-2006-0104715 | Oct 2006 | KR | national |