The present invention relates to a plasma display panel and a plasma display apparatus.
A plasma display apparatus includes a plasma display panel including electrodes and a driver supplying driving signals to the electrodes of the plasma display panel.
Barrier ribs of the plasma display panel partition discharge cells, and a phosphor layer is coated between the barrier ribs. The driver supplies driving signals to the discharge cells through the electrodes.
A discharge occurs inside the discharge cell due to the driving signals. The discharge occurs by the driving signals supplied to the discharge cell, and thus generates vacuum ultraviolet rays from a discharge gas filled in the discharge cell. The vacuum ultraviolet rays allow a phosphor coated inside the discharge cell to emit light, and thus generating visible light. An image is displayed on the screen of the plasma display panel due to the visible light.
The present invention provides a plasma display panel and a plasma display apparatus capable of improving the image quality and the driving efficiency.
A plasma display panel according to the present invention comprises a front panel including a first electrode, a second electrode, and an upper dielectric layer covering the first and second electrodes, and a rear panel including a lower dielectric layer covering a third electrode, wherein an interval between the first electrode and the second electrode ranges from 0.4 to 0.95 times an interval between the upper dielectric layer and the lower dielectric layer.
A plasma display apparatus according to the present invention comprises a plasma display panel including a front panel including a first electrode, a second electrode, and an upper dielectric layer covering the first and second electrodes, and a rear panel including a lower dielectric layer covering a third electrode, and a driver that supplies sustain signals overlapping each other to the first electrode and the second electrode, wherein an interval between the first electrode and the second electrode ranges from 0.4 to 0.95 times an interval between the upper dielectric layer and the lower dielectric layer.
A plasma display panel and a plasma display apparatus according to the present invention prevent the appearance of spotted patterns to improve the image quality and the driving efficiency.
As shown in
The plasma display panel 100 includes first electrodes Y1 to Yn and second electrodes Z1 to Zn that are parallel to each other, and third electrodes X1 to Xm intersecting the first electrodes Y1 to Yn and the second electrodes Z1 to Zn.
The driver 110 supplies driving signals to the electrodes of the plasma display panel 100. For instance, the driver 110 supplies sustain signals to the first electrodes Y1 to Yn and the second electrodes Z1 to Zn during a sustain period of a subfield. The driver 110, as shown in
As shown in
The rear panel 210 includes a rear substrate 211, a third electrode 213, a lower dielectric layer 215, a barrier rib 212, and a phosphor layer 214.
The third electrode 213 is positioned on the rear substrate 211 to intersect the first electrode 202 and the second electrode 203. The lower dielectric layer 215 insulates between the third electrodes 213. The barrier rib 212 is positioned on the lower dielectric Layer 215 and partitions discharge cells. The barrier rib 212 may include a first barrier rib 212a positioned parallel to the third electrode 213, and a second barrier rib 212b positioned to intersect the third electrode 213. A height of the first barrier rib 212a may be larger than a height of the second barrier rib 212b, and thus an exhaust characteristic of the plasma display panel is improved. The phosphor layer 214 is coated between the barrier ribs 212. The phosphor layer 214 further includes a red phosphor layer R, a green phosphor layer G, and a blue phosphor layer B. A white phosphor layer or a yellow phosphor layer may be further coated.
Widths of red, green, and blue discharge cells, in which the red phosphor layer R, the green phosphor layer G, and the blue phosphor layer B are coated, respectively, may be substantially equal to one another.
The width of at least one of the red, green, and blue discharge cells may be different from the widths of the other discharge cells. For instance, the width of the red discharge cell may be smaller than the widths of the green and blue discharge cells. The width of the green discharge cell may be substantially equal to or different from the width of the blue discharge cell. It is possible to adjust a color temperature of an image depending on the widths of the discharge cells.
As shown in
As shown in
For instance, as shown in
The transparent electrodes 202a and 203a are formed of a transparent material such as indium-tin-oxide (ITO), and the bus electrodes 202b and 203b are formed of a metal material such as silver (Ag).
The first electrode 202 and the second electrode 203 may further include a black layer darker than the transparent electrodes 202a and 203a and the bus electrodes 202b and 203b.
As shown in
For instance, if sustain signals are supplied to the first electrode 602 and the second electrode 603 during a sustain period of a subfield to be described later, a sustain discharge has to occur between the first electrode 602 and the second electrode 603. However, as shown in
Further, an unnecessary discharge may occur between the first electrode 602 and the third electrode 613 or between the second electrode 603 and the third electrode 613 as well as the sustain discharge generated between the first electrode 602 and the second electrode 603 in one discharge cell during the sustain period. Therefore, stopped patterns appear due to a difference between a luminance of the discharge cell where the sustain discharge occurs and a luminance of the discharge cell where the sustain discharge and the unnecessary discharges occur, thereby worsening the image quality.
On the other hand, as described with reference to
When the ratio g1/g2 ranges from 0.3 to 0.35 (i.e., when the interval g1 ranges from 0.3 to 0.35 times the interval g2), a positive column region of a discharge is not used because the interval g1 between the first electrode and the second electrode is excessively small. Therefore, the luminance is bad.
On the other hand, when the ratio g1/g2 ranges from 0.4 to 0.5, the luminance is good because a positive column region of a discharge is used. When the ratio g1/g2 is equal to or more than 0.52, the luminance is excellent because a positive column region of a discharge is sufficiently used.
When the interval g1 between the first electrode and the second electrode ranges from 0.3 to 0.5 times the interval between the upper dielectric layer and the lower dielectric layer, because the interval g1 between the first electrode and the second electrode is small, an unnecessary discharge is prevented from occurring between the first electrode and the third electrode or between the second electrode and the third electrode. Hence, the spotted patterns are suppressed from appearing, and the image quality is excellent. When the ratio g1/g2 ranges from 0.9 to 0.95, the generation of unnecessary discharge is reduced and the appearance of spotted patterns is further reduced. Hence, the image quality is good.
On the other hand, when the ratio g1/g2 is equal to or more than 0.98, because the interval g1 between the first electrode and the second electrode is excessively wide, the appearance of spotted patterns increases as shown in
As can be seen from the table of
As shown in
As described with reference to
The line portions 910a, 910b, 940a, and 940b may be positioned to intersect a third electrode 970 inside a discharge cell partitioned by a barrier rib 900. The line portions 910a, 910b, 940a, and 940b may be spaced apart from each other at predetermined distances d1 and d2. The predetermined distances d1 and d2 may be substantially equal to or different from each other. The line portions 910a, 910b, 940a, and 940b each have predetermined widths Wa and Wb. The projecting portions 920a, 920b, 950a, and 950b may be positioned parallel to the third electrode 970.
Since an interval between the first electrode 930 and the second electrode 960 is reduced due to the projecting portions 920a, 920b, 950a, and 950b, a firing voltage between the first electrode 930 and the second electrode 960 may be lowered.
In
As described with reference to
A discharge generated between the first projecting portions 920a and 920b of the first electrode 930 and the first projecting portions 950a and 950b of the second electrode 960 is diffused into the entire area of the discharge cell through the first and second line portions 910a and 910b of the first electrode 930 and the first and second line portions 940a and 940b of the second electrode 960.
The number of projecting portions of each of the first electrode 730 and the second electrode 760 may vary. The first electrode 930 and the second electrode 960 may further include connection portions 920c and 950c connecting at least two of the plurality of line portions 910a, 910b, 940a, and 940b to each other. The connection portions 920c and 950c make the diffusion of discharge smoother.
The first projecting portions 920a, 920b, 950a, and 950b of the first and second electrodes 930 and 960 project in a first direction, i.e., in a direction toward the center of the discharge cell, and the second projecting portions 920d and 950d project in a second direction opposite the first direction. The first projecting portions 920a, 920b, 950a, and 950b and the second projecting portions 920d and 950d projecting in the first and second directions make the diffusion of discharge smooth.
A width W1 of the first projecting portions 920a, 920b, 950a, and 950b may be substantially equal to or different from a width ¶2 of the second projecting portions 920d and 950d. A length L1 of the first projecting portions 920a, 920b, 950a, and 950b may be different from a length L2 of the second projecting portions 920d and 950d. At least one of the plurality of projecting portions 920a, 920b, 920d, 950a, 950b, and 950d may have the curvature. A portion where the projecting portions 920a, 920b, 920d, 950a, 950b, and 950d adjoin the line portions 910a, 910b, 940a and 940b may have the curvature. Further, a portion where the line portions 910a, 910b, 940a and 940b adjoin the connection portions 920c and 950c may have the curvature.
Since
As shown in
Each subfield is subdivided into a reset period for initializing the discharge cells, an address period for selecting discharge cells to be discharged, and a sustain period for representing a gray scale.
A gray level weight of the corresponding subfield may be set by adjusting the number of sustain signals supplied during the sustain period. In other words, a gray level weight having a predetermined value may be assigned to each subfield using the sustain period. For instance, in such a method of setting a gray level weight of a first subfield to 2° and a gray level weight of a second subfield to 21, a gray level weight of each subfield increases in a ratio of 2n (where n=0, 1, 2, 3, 4, 5, 6, 7). In other words, gray scale of variable images is achieved by adjusting the number of sustain signals during the sustain period of each subfield depending on the gray level weight of each subfield.
Although
As shown in
The rising ramp signal generates a weak dark discharge (i.e., a setup discharge) inside the discharge cell during the setup period, thereby accumulating a proper amount of wall charges inside the discharge cell.
During a set-down period flowing the setup period, a falling ramp signal of a polarity opposite a polarity of the rising ramp signal is supplied to the first electrode.
The falling ramp signal may gradually fall from a fourth voltage V4 lower than a peak voltage (i.e., the third voltage V3) of the rising ramp signal to a fifth voltage V5.
The supply of the falling ramp signal generates a weak erase discharge (i.e., a set-down discharge) inside the discharge cell. Hence, the remaining wall charges are uniform inside the discharge cells to the extent that an address discharge occurs stably.
During an address period following the reset period, a scan bias signal, which is substantially maintained at a voltage (i.e., a sixth voltage V6) higher than a lowest voltage (i.e., the fifth voltage V5) of the falling ramp signal, is supplied to the first electrode.
A scan signal falling from the scan bias signal by a scan voltage ΔVy may be supplied to the first electrode.
A width of the scan signal may vary in each subfield. A width of a scan signal in at least one subfield may be different from widths of scan signals in the other subfields. A width of a scan signal in a subfield may be larger than a width of a scan signal in a next subfield in time order.
When the scan signal is supplied to the first electrode, a data signal, which rises by a magnitude ΔVd of the data voltage to correspond to the scan signal, may be supplied to the third electrode.
As the voltage difference between the scan signal and the data signal is added to a wall voltage by the wall charges produced during the reset period, the address discharge may occur inside the discharge cell to which the data signal is supplied.
A sustain bias signal may be supplied to the second electrode during the address period so as to prevent the address discharge from being unstable by interference of the second electrode.
The sustain bias signal may be substantially maintained at a sustain bias voltage Vz, which is lower than a voltage of a sustain signal supplied during a sustain period and is higher than the ground level voltage GND.
During the sustain period for image display, the sustain signal may be supplied to at least one of the first electrode and the second electrode. For instance, the sustain signal may be alternately supplied to the first electrode and the second electrode.
As the wall voltage inside the discharge cell selected by performing the address discharge is added to the sustain voltage Vs of the sustain signal, every time the sustain signal is supplied, a sustain discharge, i.e., a display discharge occurs between the first electrode and the second electrode.
It is preferable that the sustain signal supplied to the first electrode overlaps the sustain signal supplied to the second electrode during the sustain period. This will be below described in detail.
As shown in
As described with reference to
In case that a sustain signal supplied to the first electrode overlaps a sustain signal supplied to the second electrode, wall charges produced by the sustain signal supplied to the first electrode may contribute to a sustain discharge generated by the sustain signal supplied to the second electrode. Therefore, although the interval between the first electrode and the second electrode is excessively smaller than the interval between the upper and lower dielectric layers or the height of the barrier rib, a reduction in the driving efficiency can be prevented.
It is preferable that at least one of a width W10 of the sustain signal supplied to the first electrode or a width W20 of the sustain signal supplied to the second electrode ranges from 4.0 μs to 6.0 μs.
As shown in (a) of
If the sustain signals having the overlap period d1 and the sustain signals having the overlap period d2 are used together, a fixed state of the wall charges distributed in the discharge cell can be prevented. Hence, image sticking is reduced. The first and second sustain signals SUS1 and SUS2 having the overlap period d1 may be supplied in at least one of a plurality of subfields of a frame, and the third and fourth sustain signals SUS3 and SUS4 having the overlap period d2 may be supplied in the other subfields.
As shown in
As shown in (a) of
As shown in (a) of
As shown in (b) of
As above, in case that the sustain signals supplied to the first and second electrodes overlap and the width and the cycle of the sustain signal change, the generation of image sticking is reduced. Further, a cycle of a sustain signal may vary in each subfield.
As shown in (a) and (b) of
A time width of at least one of the voltage rising periods, the voltage maintenance periods, and the voltage falling periods of the third sustain signal SUS3 and the fourth sustain signal SUS4 may be longer than a time width of at least one of the voltage rising periods, the voltage maintenance periods, and the voltage falling periods of the first sustain signal SUS1 and the second sustain signal SUS2.
When the sustain signals supplied to the first and second electrodes overlap each other, and a time width of at least one of the voltage rising period, the voltage maintenance period, and the voltage falling period of the sustain signal changes, the generation of image sticking is reduced.
Number | Date | Country | Kind |
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10-2006-0125127 | Dec 2006 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/KR2007/006327 | 12/6/2007 | WO | 00 | 6/5/2009 |