This application claims the benefit of Korean Patent Application No. 10-2005-0079121, filed on Aug. 27, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to an apparatus and method for driving a plasma display panel, and more particularly, to a plasma display panel driving apparatus including an energy recovery circuit for stably applying a quickly changing pulse-shaped voltage and a driving method thereof.
2. Description of Related Technology
Recently, in the field of large-sized flat-panel displays (FPDs), plasma display apparatuses including a plasma display panel (PDP) have come to public attention. In a plasma display apparatus, discharge gas is filled between two substrates of a plasma display panel, wherein a plurality of electrodes are formed on each substrate, discharge voltages are applied to the electrodes, vacuum ultraviolet radiation is generated by the discharge, and the vacuum ultraviolet radiation excites phosphor in a data driven pattern, thereby displaying images.
Referring to
Referring to
In
In an address display separation (ADS) method, which is one of a plurality of plasma display panel driving methods, a unit frame is divided into a plurality of subfields SF and each subfield SF is divided into a reset period R, an address period A, and a sustain-discharge period S, so that driving voltages as illustrated in
However, in the discharge cell structure of the plasma display panel illustrated in
In order to resolve these problems, an improved structure in which sustain-discharge electrode pairs are disposed in barrier ribs forming the lateral parts of discharge cells has been proposed.
A plasma display panel having such an improved structure may be a 3-electrode type plasma display panel or a 2-electrode type plasma display panel. The 2-electrode type plasma display panel has advantages over the 3-electrode type plasma display panel in terms of the following features. That is, in the 2-electrode type plasma display panel, since the number of electrodes and the number of required drivers are reduced compared to the 3-electrode type plasma display panel, manufacturing costs can be lowered. Also, since the 2-electrode type plasma display panel has a simple structure compared to the 3-electrode type plasma display panel, a driving method thereof can be simplified.
However, in order to drive the 2-electrode type plasma display panel, a plasma display panel driving method different from a driving method of the 3-electrode type plasma display panel is required.
In particular, a 2-electrode type plasma display panel driving method is needed to suppress heat generation when a quickly changing pulse-shaped voltages, such as an address pulse voltage or a sustain pulse voltage, are applied.
The present invention provides an apparatus for driving a 2-electrode type plasma display panel, including an energy recovery circuit configured to stably apply a quickly changing pulse-shaped voltage, and a driving method thereof.
One embodiment is a plasma display panel driving apparatus configured to apply a driving voltage to a plasma display panel during a reset period, an address period, and a sustain-discharge period so as to drive the plasma display panel. The plasma display panel includes a plurality of X electrodes extending in a first direction, a plurality of Y electrodes extending in a second direction perpendicular to the first direction, and discharge cells formed near locations where the X electrodes cross the Y electrodes. The apparatus includes an X electrode driver configured to apply the driving voltage to the X electrodes, a Y electrode driver configured to apply the driving voltage to the Y electrodes, where the X electrode driver includes an address pulse voltage supplying unit configured to supply an address pulse voltage to the X electrodes to select discharge cells to be displayed during the address period, a first energy recovery unit configured to collect and store charge from discharge cells and to then provide the stored charge to the discharge cells, during the address period, an X electrode sustain pulse voltage supplying unit configured to supply an X electrode sustain pulse voltage to the X electrodes in order to sustain-discharge selected discharge cells, during the sustain discharge period, and a second energy recovery unit configured to collect and store charge from the discharge cells and to then provide the stored charge to the discharge cells, in the sustain-discharge period.
Another embodiment is a method of driving a plasma display panel, the plasma display panel including a plurality of X electrodes extending in a first direction, a plurality of Y electrodes extending in a second direction perpendicular to the first direction, and discharge cells formed near locations where the X electrodes cross the Y electrodes. The method includes applying an address pulse voltage having a positive pulse-shaped waveform to the X electrodes and applying a scan pulse voltage with a negative pulse-shaped waveform to the Y electrodes, where discharge cells are selected to be displayed, and applying an X electrode sustain pulse voltage alternately having a sustain-discharge voltage required for sustain-discharging and a ground voltage to the X electrodes, and applying a Y electrode sustain pulse voltage alternately having the ground voltage and the sustain-discharge voltage to the Y electrodes such that the Y electrode sustain pulse voltage has a polarity opposite of the X electrode sustain pulse voltage, where the selected discharge cells are sustain-discharged.
Another embodiment is a plasma display panel driving apparatus configured to apply a driving voltage to a plasma display panel during a reset period, an address period, and a sustain-discharge period so as to drive the plasma display panel, the plasma display panel including a plurality of X electrodes extending in a first direction, a plurality of Y electrodes extending in a second direction perpendicular to the first direction, and discharge cells formed near locations where the X electrodes cross the Y electrodes. The apparatus includes an X electrode driver configured to apply the driving voltage to the X electrodes, a Y electrode driver configured to apply the driving voltage to the Y electrodes, where the X electrode driver includes an address pulse voltage supplying unit configured to supply an address pulse voltage to the X electrodes to select discharge cells to be displayed during the address period, and a first energy recovery unit configured to collect and store charge from discharge cells and to then provide the stored charge to the discharge cells, during the address period.
The above and other features and advantages will become more apparent by describing in detail exemplary embodiments with reference to the attached drawings in which:
Certain embodiments will now be described more fully with reference to the accompanying drawings, in which embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Like reference numerals in the drawings denote like elements, and thus their descriptions will not be repeated.
Referring to
The image processor 402 receives image signals, such as PC signals, DVD signals, video signals, TV signals, etc., from an external source, converts the image signals into digital signals, performs image processing on the converted digital signals to generate internal image signals, and then transfers the image signals to the logic controller 404. The image signals include red (R) image data signals, green (G) image data signals, blue (B) image data signals, a clock signal, a vertical synchronization signal, a horizontal synchronization signal, etc.
In the 2-electrode type plasma display panel driving apparatus, the logic controller 404 performs gamma correction, Automatic Power Control (APC), etc. on the internal image signals transferred from the image processor 402, and generates an X electrode driver control signal Sx and a Y electrode driver control signal SY. The X electrode driver control signal Sx and the Y electrode driver control signal SY are respectively transferred to the X electrode driver 413 and the Y electrode driver 415.
In the 2-electrode type plasma display panel driving apparatus, the X electrode driver 413 receives the X electrode driver control signal SX from the logic controller 404 and outputs an X electrode driver driving signal so that an X electrode driving voltage is applied to X electrodes X1 through Xm of the plasma display panel. The Y electrode driver 415 receives the Y electrode driver control signal SY from the logic controller 404 and outputs a Y electrode driver driving signal so that a Y electrode driving voltage is applied to Y electrodes Y1 through Yn of the plasma display panel.
In the 2-electrode type plasma display panel 417 in which the X electrodes X1 through Xm intersect the Y electrodes Y1 through Yn as illustrated in
Referring to
In the 2-electrode type plasma display panel having the structure described above, driving voltages are applied to discharge spaces of discharge cells through two type electrodes of the X electrodes 513 and the Y electrodes 515. That is, the X electrodes 513 and the Y electrodes 515 of the 2-electrode type plasma display panel structure act as common electrodes 212, scan electrodes 214, and address electrodes 216 of a 3-electrode type plasma display panel structure illustrated in
A space between the front substrate 502 and the rear substrate 504 is partitioned by the barrier ribs 506, thus forming discharge cells which are unit discharge spaces. Each discharge cell has a front part (front substrate side), a rear part (rear substrate side), and lateral parts (barrier rib sides).
Since discharge gas having a pressure (approximately, 0.5 atm) lower than an atmospheric pressure is filled in the internal space of the discharge cell, charges collide with discharge gas particles when an electric field is formed according to driving voltages applied to the respective electrodes of the discharge cell and thus a plasma discharge is generated, so that vacuum ultraviolet radiation is generated by the plasma discharge. The discharge gas may be a mixture of Xe gas and at least one of Ne gas, He gas, and Ar gas.
The barrier ribs 506 define discharge cells which are basic units forming an image and prevent cross talk between the discharge cells.
The barrier ribs 506 can be formed to contain dielectrics. The dielectrics are used as insulation films of the X electrodes 513 and the Y electrodes 515, are disposed on the barrier ribs 506, and have high insulation resistance. Some of the charge generated by the discharge is attracted by an electric power according to the polarities of driving voltages applied to the respective electrodes and is accumulated near the dielectrics to thus form wall charges, so that a wall charge voltage formed by the wall charges is summed with the driving voltages applied to the respective electrodes, thus providing electric fields in the discharge spaces.
Also, the barrier ribs 506 can include dielectric layers used as insulation films of the X and Y electrodes 513 and 515. That is, in the 2-electrode type plasma display panel, the barrier ribs 506 can be formed with dielectrics or include separate dielectric layers.
In the phosphor layers 508, a photo luminescence mechanism in which vacuum ultraviolet (VUV) radiation generated by the discharge is absorbed and electrons excited by the VUV radiation emit visible rays when reaching a stable state, is performed. In order to display a color image on the plasma display panel, the phosphor layers 508 can include red-emitting phosphor layers, green-emitting phosphor layers and blue-emitting phosphor layers, wherein a red-emitting phosphor layer, a green-emitting phosphor layer, and a blue-emitting phosphor layer are positioned in proximal discharge cells to form a unit pixel. The red-emitting phosphor may be (Y,Gd)BO3:EU3+, the green-emitting phosphor may be Zn2SiO4:Mn2+, and the blue-emitting phosphor may be BaMgAl10O17:Eu2+.
The protection layer 510 protects the dielectrics or the dielectric layers and accelerates secondary electrons when discharge occurs, thereby facilitating the discharge. The protection layer 510 is formed of a material such as MgO.
In the 2-electrode type plasma display panel according to one embodiment, the cross-section of a discharge cell resulting by cutting the discharge cell parallel to a front or rear substrate and perpendicular to lateral parts (that is, to barrier ribs) of the discharge cell may be a circle, or a polygon, such as a square, a hexagon, an octagon, etc. A structure in which the cross-section of a discharge cell is a circle is illustrated in
When a discharge cell has a circular cross-section, the discharge cell has a cylindrical structure (see
Each discharge cell may have a substantially cylindrical structure as illustrated in
In
In
Referring to
As illustrated in
Since driving voltages are applied to discharge cells through 3 type electrodes in a 3-electrode type plasma display panel while driving voltages are applied to discharge cells through 2 type electrodes in a 2-electrode type plasma display panel, the driving voltage waveforms of
As seen in
In an address period Pa, a scan pulse voltage (the scan pulse voltage is maintained at Vya1 after falling from Vya1 to Vya2) with a negative pulse waveform is applied to the Y electrodes Y1 through Yn, and an address pulse voltage (the address pulse voltage is maintained at Vg after rising from Vg to Vxa) with a positive pulse waveform is applied to the X electrodes X1 through Xm, so that discharge cells to be sustain-discharged in a following sustain-discharge period Ps are selected.
In the sustain-discharge period Ps, a positive sustain-discharge voltage +Vs and a negative sustain-discharge voltage −Vs are alternately applied to the Y electrodes Y1 through Yn, wherein the ground voltage Vg can be applied during a predetermined period between +Vs and −Vs, and the ground voltage Vg is applied to the X electrodes X1 through Xm, so that the discharge cells selected in the address period Pa are sustain-discharged.
Comparing
Referring to
In the reset period Pr, by equalizing the first Y electrode reset voltage Vyr1 to a sustain discharge voltage Vs, the number of drivers required for driving a plasma display panel can be reduced.
In the address period Pa, an address pulse voltage with a positive pulse waveform is applied to the X electrodes X1 through Xm and a scan pulse voltage with a negative pulse waveform is applied to the Y electrodes Y1 through Yn, according to control signals corresponding to external image signals input to a plasma display apparatus, so that discharge cells to be displayed are selected.
In the address period Pa, the address pulse voltage becomes the ground voltage Vg and the X electrode address voltage Vxa with predetermined intervals, as illustrated in
In the address period Pa, the scan pulse voltage becomes the first Y electrode address voltage Vya1 and the second Y electrode address voltage Vya2 with predetermined intervals, as illustrated in
In the address period Pa, the first Y electrode address voltage Vya1 can be greater than or equal to the ground voltage Vg.
In the sustain-discharge period Ps, an X electrode sustain pulse voltage alternately having the sustain-discharge voltage Vs causing sustain-discharge and the ground voltage Vg is applied to the X electrodes X1 through Xm, and a Y electrode sustain-pulse voltage alternately having the ground voltage Vg and the sustain discharge voltage Vs is applied to the Y electrodes Y1 through Yn, according to control signals corresponding to external image signals input to the plasma display apparatus, wherein the X electrode sustain pulse voltage has a polarity opposite to the Y electrode sustain pulse voltage, so that discharge cells selected in the address period Pa are sustain-discharged.
When the driving voltages with the waveforms are applied to the X electrodes X1 through Xm and the Y electrodes Y1 through Yn to drive the 2-electrode type plasma display panel, the address pulse voltages applied in the address period Pa and the sustain pulse voltages (X electrode sustain pulse voltage and the Y electrode sustain pulse voltage) applied in the sustain-discharge period Ps are quickly changing pulse-shaped voltages. Also, the address pulse voltages and the sustain pulse voltages are frequently applied in response to image signals input from an external source to the plasma display apparatus.
As such, frequently applying the quickly changing pulse-shaped voltages to the respective electrodes can put a large burden on switching devices which have high power consumption. Accordingly, when the quickly changing pulse-shaped voltages are applied to the respective electrodes through the switching devices, power consumption of the switching devices needs to be reduced.
In order to reduce the power consumption of the switching devices, an energy recovery circuit (ERC) for reducing consumption power using LC resonance between a resonance inductor and a panel capacitor is used. The ERC will be described in detail later with reference to
In the address period Pa, since the scan pulse voltage applied to the Y electrodes Y1 through Yn quickly changes but is not frequently applied, the above problem is not significant.
Referring to
The discharge cells of the 3-electrode type plasma display panel include common electrodes, scan electrodes, and address electrodes. By applying driving voltages, discharge is generated between the common electrodes and the address electrodes, between the scan electrodes and the address electrodes, and between the scan electrodes and the common electrodes.
In the upper part of
In the middle part of
In the lower part of
The discharge cells of the 2-electrode type plasma display panel include X electrodes and Y electrodes. As shown in the upper part of
In the lower part of
The X electrode sustain pulse voltage applied in the sustain-discharge period Ps shown in
Hereinafter, when the X electrode sustain pulse voltage, the Y electrode sustain pulse voltage, and the address pulse voltage are applied, a method of reducing power consumption using an energy recovery circuit will be described.
When a square pulse-shaped voltage discontinuously changing between a first voltage (for example, the sustain-discharge voltage Vs or the X electrode address voltage Vxa) and a second voltage (for example, the ground voltage Vg) is applied to respective electrodes (see
In order to resolve the problem, a webber type energy recovery circuit (ERC) including a charge capacitor and a resonance inductor is used (see
A process in which the energy recovery circuit illustrated in the lower part of
In the lower part of
In the rising period, since a sustain discharge voltage switching device Ss, a ground voltage switching device Sg, and the falling period switching device Sf are open and the rising period switching device Sr is shorted, charge accumulated in the charge capacitor Ce in the previous period moves to the panel capacitor Cp via the rising period switching device Sr, the rising period diode Dr, and the resonance inductor L, so that a voltage applied to the right terminal of the panel capacitor Cp gradually rises.
In the first sustain period, since the ground voltage switching device Sg, the rising period switching device Sr, and the falling period switching device Sf are open and the sustain discharge voltage switching device Ss is shorted, a sustain-discharge voltage Vs supplied from an external power source is applied to the right terminal of the panel capacitor Cp and maintained for a predetermined time.
In the falling period, since the sustain discharge voltage switching device Ss, the ground voltage switching device Sg, and the rising period switching device Sr are open and the falling period switching device Sf is shorted, charge in the panel capacitor Cp moves to the charge capacitor Ce via the resonance inductor L, the falling period diode Df, and the falling period switching device Sf, so that a voltage applied to the right terminal of the panel capacitor Cp gradually falls.
In the second sustain period, since the sustain-discharge voltage switching device Ss, the rising period switching device Sr, and the falling period switching device Sf are open and the ground voltage switching device Sg is shorted, the ground voltage Vg is applied to the right terminal of the panel capacitor Cp and maintained for a predetermined time.
As such, by applying a pulse-shaped voltage as illustrated in
Meanwhile, if the energy recovery circuit does not normally operate, ‘hard switching’ can occur at the ends of the rising period and falling period as illustrated in
As such, when the quickly changing pulse-shaped voltage must be frequently applied, it is important that the energy recovery circuit normally operate.
Referring to
The X electrode driver 1300 (413 of
The X electrode driver 1300 operates the address pulse voltage supply unit 1302 and the first energy recovery unit 1304 and applies the address pulse voltage to X electrodes X1 through Xm during an address period. Also, the X electrode driver 1300 operates the X electrode sustain pulse voltage supply unit 1312 and the second energy recovery unit 1314 and applies the X electrode sustain pulse voltage to the X electrodes X1 through Xm during a sustain-discharge period.
Referring to
The address pulse voltage supply unit 1302 includes a first high level switching device Ss1 for supplying or blocking the high level voltage (the X electrode address voltage Vxa) of the address pulse voltage and a first low level switching device Sg1 for supplying or blocking the low level voltage (the ground voltage Va) of the address pulse voltage.
The first energy recovery unit 1304 collects and accumulates charge from discharge cells in the address period and then provides the charged charge to the discharge cells.
The first energy recovery unit 1304 includes a first resonance inductor L1, a first charge capacitor Ce1, and a first energy recovery controller 1305, as illustrated in
The first energy recovery controller 1305 includes a first rising period switching device Sr1, a first falling period switching device Sf1, a first rising period diode Dr1, and a first falling period diode Df1, and controls an operation in a falling period for accumulating charge collected from the discharge cells (corresponding to the panel capacitor Cp) in the first charge capacitor Ce1 and an operation in a rising period for providing the charge accumulated in the first charge capacitor Ce1 in the discharge cells. That is, in the falling period, the first falling period switching device Sf1 is shorted so that charge collected from the discharge cells Cp is accumulated in the first charge capacitor Ce1. In the rising period, the first rising period switching device Sr1 is shorted so that charge accumulated in the first charge capacitor Ce1 is provided to the discharge cells.
As such, the first energy recovery unit 1304 moves charge accumulated in the first charge capacitor Ce1 to the panel capacitor Cp in the rising period and moves the charges accumulated in the panel capacitor Cp in the falling period to the first charge capacitor Ce1, using LC resonance between the panel capacitor Cp, the first resonance inductor L1, and the first charge capacitor Ce1, thereby reducing power consumption when a driving voltage is applied.
The X electrode sustain pulse voltage supply unit 1312 supplies an X electrode sustain pulse voltage including a sustain discharge voltage Vs having a high level and a ground voltage Vg having a low level.
The X electrode sustain pulse voltage supply unit 1312 includes a second high level switching device Ss2 for supplying or blocking the high level voltage (the sustain discharge voltage Vs) of the X electrode sustain pulse voltage, and a second low level switching device Sg2 for supplying or blocking the low level voltage (the ground voltage Vg) of the X electrode sustain pulse voltage.
The second energy recovery unit 1314 accumulates charges from the discharge cells in the sustain-discharge period and then provides the accumulated charges to the discharge cells.
The second energy recovery unit 1314 includes a second resonance inductor L2, a second charge capacitor Ce2, and a second energy recovery controller 1315, as illustrated in
The second energy recovery controller 1315 includes a second rising period switching device Sr2, a second falling period switching device Sf2, a second rising period diode Dr2, and a second falling period diode Df2, and controls an operation in the falling period of accumulating charge collected from the discharge cells (corresponding to the panel capacitor Cp) in the second charge capacitor Ce2 and an operation in the rising period of providing charge accumulated in the second charge capacitor Ce1 to the discharge cells Cp. That is, in the falling period, the second falling period switching device Sf2 is shorted so that charge collected from the discharge cells Cp is accumulated in the second charge capacitor Ce2, and in the rising period, the second rising period switching device Sr2 is shorted so that charge accumulated in the second charge capacitor Ce2 is provided to the discharge cells Cp.
As such, the second energy recovery unit 1314 moves charge accumulated in the second charge capacitor Ce2 to the panel capacitor Cp in the rising period and moves charge accumulated in the panel capacitor Cp to the second charge capacitor Ce2 in the falling period, using LC resonance between the panel capacitor Cp, the second resonance inductor L2, and the second charge capacitor Ce2, thereby reducing power consumption when a driving voltage is applied.
In
The Y electrode driver 1400 operates the reset pulse voltage supply unit 1406 to apply a ramp type reset pulse voltage to Y electrodes Y1 through Yn in a reset period, operates the scan pulse voltage supply unit 1408 to apply a scan pulse voltage to the Y electrodes Y1 through Yn in an address period, and operates the Y electrode sustain voltage supply unit 1402 and the third energy recovery unit 1404 in a sustain discharge period to apply the Y electrode sustain pulse voltage to the Y electrodes Y1 through Yn.
Referring to
The Y electrode sustain pulse voltage supply unit 1402 includes a third high level switching device Ss3 for supplying or blocking the high level voltage (the sustain discharge voltage Vs) of the Y electrode sustain pulse voltage, and a third low level switching device Sg3 for supplying or blocking the low level voltage (the ground voltage Vg) of the Y electrode sustain pulse voltage.
The third energy recovery unit 1404 collects and accumulates charge from discharge cells in the sustain-discharge period and then provides the accumulated charge to the discharge cells.
The third energy recovery unit 1404 includes a third resonance inductor L3, a third charge capacitor Ce3, and a third energy recovery controller 1405, as illustrated in
The third energy recovery controller 1405 includes a third rising period switching device Sr3, a third falling period switching device Sf3, a third rising period diode Dr3, and a third falling period diode Df3, and controls an operation in a falling period of accumulating charge collected from discharge cells (corresponding to a panel capacitor Cp) in the third charge capacitor Ce3 and an operation in a rising period of providing charge accumulated in the third charge capacitor Ce3 to the discharge cells. That is, in the falling period, the third falling period switching device Sf3 is shorted so that charge collected from the discharge cells is accumulated in the third charge capacitor Ce3, and in the rising period, the third rising period switching device Sr3 is shorted so that charge accumulated in the third charge capacitor Ce3 is provided to the discharge cells.
As such, the third energy recovery unit 1404 moves charges accumulated in the third charge capacitor Ce3 to the panel capacitor Cp in a rising period, and moves charges accumulated in the panel capacitor Cp to the third charge capacitor Ce3 in a falling period, using LC resonance between the panel capacitor Cp, the third resonance inductor L3, and the third charge capacitor Ce3, thereby reducing power consumption when a driving voltage is applied.
The reset pulse voltage supply unit 1406 supplies a ramp-shaped reset pulse voltage to Y electrodes in order to initialize all discharge cells in a reset period (see
The scan pulse voltage supply unit 1408 supplies a scan pulse voltage to the Y electrodes in order to select discharge cells to be displayed in an address period (see
Various embodiments reduce power consumption for circuits where a quickly changing pulse-shaped voltage is frequently applied to X electrodes or Y electrodes of a 2-electrode type plasma display panel (that is, when an address pulse voltage is applied to X electrodes, when an X electrode sustain pulse voltage is applied to X electrodes, and when an Y electrode sustain pulse voltage is applied to Y electrodes). In
Various electronic devices may be used as the switching devices in these embodiments. In
As described above, because a 2-electrode type plasma display panel driving circuit includes an energy recovery circuit, a quickly changing pulse-shaped voltage can be stably applied.
While this description 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 may be made without departing from the spirit and scope.
Number | Date | Country | Kind |
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10-2005-0079121 | Aug 2005 | KR | national |