KR100490529B1 - Method for driving plasma display panel - Google Patents

Abstract

In the driving method according to the present invention, the wall charges are formed in the discharge cells selected from the discharge cells of the plasma display panel based on the input image data, and the sustain discharge pulses are generated to cause the sustain discharge in the discharge cells in which the wall charges are formed. The periodically applied process to the electrode lines of the plasma display panel is a driving method which is repeatedly performed in a sub-field unit which is the minimum driving period. Here, the widths of the last applied pulses among the sustain discharge pulses are smaller than the widths of the other sustain discharge pulses. The presence and the number of the last pulses are set according to the number of pixels that have been selected in the sub-field to which the last pulses are to be applied, and the number of the last pulses is set in proportion to the number of pixels that have been selected in the sub-field.

Description

Method for driving plasma display panel {Method for driving plasma display panel}

The present invention relates to a method of driving a plasma display panel, and more particularly, to a method of driving a plasma display panel of a three-electrode surface discharge method.

1 shows the structure of a conventional three-electrode surface discharge plasma display panel. 2 illustrates an electrode line pattern of the plasma display panel of FIG. 1. 3 shows one discharge cell of the panel of FIG. 1. Referring to the drawings, between the front and rear glass substrates 10 and 13 of the general surface discharge plasma display panel 1, the address electrode lines A _R1 , A _G1 , ..., A _Gm , A _Bm , Dielectric layers 11 and 15, Y electrode lines Y ₁ , ..., Y _n , X electrode lines X ₁ , ..., X _n , fluorescent layer 16, barrier rib 17 And a magnesium monoxide (MgO) layer 12 as a protective layer.

The address electrode lines A _R1 , A _G1 ,..., A _Gm , A _Bm are formed in a predetermined pattern on the front surface of the rear glass substrate 13. The lower dielectric layer 15 is formed in front of the address electrode lines A _R1 , A _G1 ,..., A _Gm , A _Bm . The barrier ribs 17 are formed on the front surface of the lower dielectric layer 15 in a direction parallel to the address electrode lines A _R1 , A _G1 ,..., A _Gm and A _Bm . These partitions 17 function to partition the discharge area of each discharge cell and to prevent optical cross talk between each discharge cell. The fluorescent layer 16 is formed between the partition walls 17.

The X electrode lines (X ₁ , ..., X _n ) and the Y electrode lines (Y ₁ , ..., Y _n ) are the address electrode lines (A _R1 , A _G1 , ..., A _Gm , A _Bm ) is formed in a predetermined pattern on the rear surface of the front glass substrate 10 to be orthogonal to each other. Each intersection defines a corresponding discharge cell. Each X electrode line (X ₁ , ..., X _n ) and each Y electrode line (Y ₁ , ..., Y _n ) are indium tin oxide (ITO) electrode lines (X _{na in} FIG. 3) of a transparent conductive material. , Y _na ) and a bus electrode line (X _nb , Y _nb of FIG. 3) of a metal material are formed to be combined with each other. The upper dielectric layer 11 is formed after the X electrode lines X ₁ ,..., X _n and the Y electrode lines Y ₁ ,..., Y _n . A magnesium monoxide (MgO) layer 12 for protecting the panel 1 from a strong electric field is formed by applying the entire surface to the back surface of the upper dielectric layer 11. The plasma forming gas is sealed in the discharge space 14.

The driving method basically applied to the plasma display panel is a method in which the reset, address, and sustain discharge steps are sequentially performed in the unit subfield. In the reset step, the residual wall charges in the previous subfield are erased and driven so that the space charges are generated evenly. In the address step, the wall charges are driven to be formed in the selected discharge cells. In the sustain discharge step, light is driven in the discharge cells in which the wall charges are formed in the addressing discharge step. That is, when a pulse of a relatively high voltage is alternately applied to all the X electrode lines X ₁ , ..., X _n and all the Y electrode lines Y ₁ , ..., Y _n , the wall charge Causes surface discharge in the formed discharge cells. At this time, a plasma is formed in the gas layer, and the fluorescent layer 16 is excited by the ultraviolet radiation to generate light.

4 illustrates a unit frame for displaying gray scales on the plasma display panel of FIG. 1 according to a general sequential driving method. Referring to FIG. 4, a unit frame is divided into six subfields SF1, SF6 to realize time division gray scale display. Further, each subfield SF1, ..., SF6 is divided into address periods A1, ..., A6 and sustain discharge periods S1, ..., S6.

In each address period A1, ..., A6, a display data signal is applied to the address electrode lines (A _R1 , A _G1 , ..., A _Gm , A _{Bm in} FIG. 1) and each Y electrode line Scan pulses corresponding to (Y ₁ , ..., Y _n ) are applied sequentially. Accordingly, when a high level display data signal is applied while the scan pulse is applied, wall charges are formed by the address discharge in the corresponding discharge cell, and wall charges are not formed in the discharge cell that is not.

In each sustain discharge period (S1, ..., S6), the milky way is applied to all Y electrode lines (Y ₁ , ..., Y _n ) and all X electrode lines (X ₁ , ..., X _n ). Dedicated pulses are alternately applied to cause display discharge in discharge cells in which wall charges are formed in corresponding address periods A1, ..., A6. Therefore, the luminance of the plasma display panel is proportional to the length of the sustain discharge periods S1, ..., S6 occupied in the unit frame. In the case of Fig. 4, the lengths of the sustain discharge cycles S1, ..., S6 occupy a unit frame are 63T (T is unit time). Therefore, it can be displayed in 64 gray levels including the case where it is not displayed once in the unit frame.

FIG. 5 shows sustain discharge periods S1, ..., S6 of all sub-fields (SF1, ..., SF6 of FIG. 4) and subsequent address periods A2, ..., by the conventional driving method. Show part of A1). In FIG. 5, reference numeral S _Y1..n denotes a Y driving signal applied to all Y electrode lines (Y ₁ ,..., Y _{n in} FIG. 1), and S _X1 .. _n denotes all X electrode lines. Each of the X driving signals applied to (X ₁ , ..., X _{n in} FIG. 1) is indicated.

Referring to FIG. 5, all Y electrode lines Y ₁ , ..., Y _n and all X electrode lines X ₁ , ..., in each sustain discharge period S1, ..., S6. The sustain discharge pulse P _S is alternately applied to X _n ) to cause display discharge in discharge cells in which wall charges are formed in corresponding address periods A1,..., A6. Here, the sustain discharge and the preliminary reset discharge are simultaneously performed by making the width of the sustain discharge pulse P _SL finally applied smaller than the width of the other pulses P _S. Accordingly, the effect of the reset discharge performed primarily in the address periods A2, ..., A1 of the next subfield is increased. Since the last sustain discharge pulse P _SL is applied to all the X electrode lines X ₁ ,..., Xn, all the Y electrode lines (in the address period A2,..., A1) of the next subfield. Y ₁ , ..., Y _n ) are applied with reset pulses P _R1 , P _R2 , and P _R3 . That is, the voltage gradually increasing the first reset pulse (P _R1), the first reset pulse (P _R1) and an opposite polarity while a narrow second reset pulse (P _R2), and a second reset pulse (P _R2) wide as opposed to A third reset pulse P _R3 having a polarity and gradually increasing voltage is applied to all of the Y electrode lines Y ₁ ,..., Y _n , so that the wall charges are erased and the space charges are evenly formed. However, the wall charges are not completely erased despite such a reset driving, so at least one front strong discharge is performed in units of frames. That is, as the longer and longer pulse (not shown) than the sustain discharge pulse P _S is applied to all the Y electrode lines Y ₁ ,..., Y _n , not only selected pixels but also unselected pixels Erasing discharge occurs even at.

According to the conventional driving method as shown in FIG. 5, the width of the pulse P _SL which is applied last in all sustain discharge periods S1,..., S6 is narrow. This results in the unnecessary narrow pulse P _SL being applied when the number of pixels selected in the corresponding address periods A1, ..., A6 is small. In addition, when the number of pixels that have been selected in the corresponding address periods A1, ..., A6 is large, the result is that an insufficient number of narrow pulses P _SL is applied. Accordingly, not only the wall charge erase efficiency is lowered, but also the contrast of the display is lowered because at least one front strong discharge is performed in units of frames in order to improve the wall charge erase efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for driving wall charge erasing efficiency and display contrast in a method of driving a plasma display panel.

The driving method of the present invention for achieving the above object, the wall charges are formed in the discharge cells selected from the discharge cells of the plasma display panel by the input image data, causing the sustain discharge in the discharge cells formed with the wall charges For this reason, the process of applying the sustain discharge pulse periodically to the electrode lines of the plasma display panel is a driving method which is repeatedly performed in a sub-field unit which is the minimum driving period. Here, the widths of the last pulses applied last among the sustain discharge pulses are smaller than the widths of the other sustain discharge pulses. The presence and the number of the last pulses are set according to the number of pixels selected in the sub-field to which the last pulses are to be applied, and the number of the last pulses is proportional to the number of pixels selected in the sub-field. do.

Accordingly, since the last pulses are properly applied to the corresponding sub-field, the wall charge erase efficiency can be increased. In addition, the number of front side strong discharges for increasing the wall charge erasing efficiency can be reduced, thereby increasing the contrast of the display.

Hereinafter, preferred embodiments of the present invention will be described in detail.

In this embodiment, the widths of the last pulses applied last among the discharge pulses are smaller than the widths of the other discharge pulses. The presence and the number of the last pulses are set according to the number of pixels selected in the sub-field to which the last pulses are to be applied, and the number of the last pulses is set in proportion to the number of pixels selected in the sub-field. 6 shows a sustain discharge period S1 of the first subfield (SF1 in FIG. 4) and a part of the address period A2 of the next subfield (SF2 in FIG. 4) according to the driving method of the present invention. 7 shows a sustain discharge period S2 of the second subfield SF2 and a part of the address period A3 of the next subfield SF3 of FIG. 4 according to the driving method of the present invention. 6 and 7 the same reference numerals as used in FIG. 5 indicate the target of the same function.

Referring to FIG. 6, there is no narrow pulse that is applied last in the sustain discharge period S1 of the first subfield. The driving waveforms of FIG. 6 are applied when none of the pixels selected in the address period (A1 of FIG. 4) of the first subfield SF1 is present. That is, when none of the pixels have been selected, since wall charges are hardly present, the wall charges are sufficiently caused by the reset pulses P _R1 , P _R2 and P _{R3 of the} next address period A2 without applying a narrow pulse. Can be erased. Therefore, when none of the pixels have been selected, the wall charge erase efficiency can be increased by not applying unnecessary narrow pulses.

Referring to FIG. 7, there are two narrow pulses P _{SL that} are applied last in the sustain discharge period S2 of the second subfield. Such driving waveforms of FIG. 7 are applied when there are many pixels selected in the address period (A2 of FIG. 4) of the second subfield SF2, for example, when a majority of the pixels are selected. That is, when there are many pixels selected, since the wall charges are relatively large, the effect of the preliminary erase discharge is increased by applying a plurality of narrow pulses P _SL . Accordingly, the wall charges can be sufficiently erased by the reset pulses P _R1 , P _R2 , and P _{R3 of the} following address period A3. In addition, since the number of front strong discharges performed in units of frames can be reduced in order to increase wall charge erasing efficiency, the contrast of the display is also relatively high.

As described above, according to the driving method of the plasma display panel according to the present invention, since the last narrow pulses in the sustain discharge period are appropriately applied to the corresponding sub-field, the wall charge erase efficiency can be increased. In addition, the number of front side strong discharges for increasing the wall charge erasing efficiency can be reduced, thereby increasing the contrast of the display.

The present invention is not limited to the above embodiments, but may be modified and improved by those skilled in the art within the spirit and scope of the invention as defined in the claims.

1 is a perspective view showing an internal structure of a conventional three-electrode surface discharge plasma display panel.

FIG. 2 is an electrode line pattern diagram of the plasma display panel of FIG. 1.

3 is a cross-sectional view illustrating one discharge cell of the panel of FIG. 1.

4 is a block diagram illustrating a unit frame for displaying gray scales on the plasma display panel of FIG. 1 according to a general sequential driving method.

5 is a timing diagram showing driving signals applied to sustain electrode lines in all sub-fields by the conventional driving method.

6 is a timing diagram showing driving signals applied to sustain electrode lines in a first sub-field according to the driving method of the present invention.

7 is a timing diagram showing driving signals applied to sustain electrode lines in a second sub-field according to the driving method of the present invention.

<Explanation of symbols for the main parts of the drawings>

1 ... plasma display panel, 10 ... front glass substrate,

11, 15 dielectric layer, 12 magnesium monoxide layer,

13 ... back glass substrate, 14 ... discharge space,

16 fluorescent layers, 17 bulkheads,

X ₁ , ..., X _n ... X electrode line, Y ₁ , ..., Y _n ... Y electrode line,

A _R1 , A _G1 , ..., A _Gm , A _Bm ... address electrode line,

X _na , Y _na ... ITO electrode line, X _nb , Y _nb ... bus electrode line,

SF1, ..., SF6 ... subfield, A1, ..., A6 ... address cycle,

S1, ..., S6 ... _Dielectric cycle, S _Y1..n ... Y drive signal,

S _X1..n ... X drive signal, P _S ...

P _SL ... pulse for the final fat discharge,

P _R1 , P _R2 , P _R3 ... reset pulses.

Claims (3)

The wall charges are formed in the discharge cells selected from the discharge cells of the plasma display panel by the input image data, and the sustain discharge pulses are applied to the electrode lines of the plasma display panel to cause the sustain discharge in the discharge cells in which the wall charges are formed. In the driving method that is periodically applied to the field is repeatedly performed in the sub-field unit which is the minimum driving period, Among the sustain discharge pulses, the width of the last pulses applied last is narrower than the width of the other sustain discharge pulses, The presence and the number of the last pulses are set according to the number of pixels selected in the sub-field to which the last pulses are to be applied, and the driving is set such that the number of the last pulses is proportional to the number of pixels selected in the sub-field. Way. The method of claim 1, The last pulse does not exist if not all the pixels in the sub-field have been selected. delete