KR100349922B1 - Apparatus for driving plasma display panel - Google Patents

Abstract

The driving method of the plasma display panel according to the present invention is a driving method in which the reset, address and sustain-discharge steps are sequentially performed in sub-field units for time division gray scale display. In the reset step, the state of the discharge space in the plasma display panel is initialized. In the addressing step, a wall is placed on the discharge cells selected from among the discharge cells by a display data signal applied to the address electrode lines of the plasma display panel and a scan signal applied to the Y electrode lines arranged orthogonally to the address electrode lines. Charges are formed. In the sustain-discharge step, sustain-discharge pulses are periodically applied to X and Y electrode lines arranged parallel to each other to cause sustain-discharge in discharge cells in which wall charges are formed. Here, the pulse width of the scan signal and corresponding display data signal applied in the address step is inversely proportional to the execution time of the sustain-discharge step in the previous sub-field.

Description

{Apparatus 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 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.

In the above-described driving method, in order to perform gradation display on a plasma display panel, a time division driving method is performed in which a gradation display is performed by dividing a frame, which is a unit display period, into subfields of different display times. . A case in which eight subfields are set per unit frame in order to perform 256 (2 ⁸ ) grayscale display with 8-bit image data will be described below.

In such a method of driving a plasma display panel, conventionally, the pulse width of the scan signal applied in the address step and the corresponding display data signal is always constant in all the sub-fields. 4 shows a conventional driving method of a plasma display panel.

Referring to FIG. 4, a unit frame is divided into eight subfields SF1,..., SF8 to realize time division gray scale display. Further, each subfield SF1, ..., SF8 is divided into address periods A1, ..., A8 and sustain discharge periods S1, ..., S8.

In each address period A1, ..., A8, 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.

Here, the pulse widths of the scan signal and corresponding display data signal applied in each address period A1, ..., A8 are always constant in all the sub-fields SF1, ..., SF8.

In each sustain discharge period (S1, ..., S8), 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, causing 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, ..., S8 occupy in the unit frame. The lengths of the sustain discharge cycles S1, ..., S8 occupy a unit frame are 255T (T is the unit time). Therefore, it can be displayed in 256 gray levels, including the case where it is not displayed once in a unit frame.

Here, the time 1T corresponding to 2 ⁰ in the sustain discharge period S1 of the first subfield SF1 and the time corresponding to 2 ¹ in the sustain discharge period S2 of the second subfield SF2 2T) is, the third time (4T) corresponding to include ²² sustain discharge period (S3) of the subfield (SF3) is the fourth, the sustain discharge period (S4) of the subfield (SF4) corresponding to ²³ The time 8T corresponds to 2 ⁴ in the sustain discharge period S5 of the fifth subfield SF5, and the time 16T corresponds to 2 ⁵ in the sustain discharge period S6 of the sixth subfield SF6. The corresponding time 32T corresponds to the time 64T corresponding to 2 ⁶ in the sustain discharge period S7 of the seventh subfield SF7, and the sustain discharge period S8 of the eighth subfield SF8. Times 128T corresponding to 2 ⁷ are set respectively.

Accordingly, when the subfield to be displayed among the 8 subfields is appropriately selected, it can be seen that display of 256 gray levels can be performed including all zero (zero) gray levels that are not displayed in any of the subfields.

As mentioned above, according to the conventional driving method, the pulse widths of the scan signal and the corresponding display data signal applied in each address period A1, ..., A8 are all sub-fields SF1,. .., always constant in SF8). However, the amount of space charge in the address period (eg A2) of either sub-field is proportional to the sustain-discharge period (eg S1) in the previous sub-field. Therefore, the shorter the sustain-discharge period (eg, S1) in the previous sub-field, the less addressing is performed in the address period (eg, A2) of the next sub-field, so that image quality is improved. You can drop it. This phenomenon is more severe in low gray display screens.

SUMMARY OF THE INVENTION An object of the present invention is to provide a driving method for driving a plasma display panel in which the address discharge characteristic in each sub-field for time division gray scale display is uniform and the image quality can be improved.

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 driving timing diagram illustrating a conventional driving method of the plasma display panel.

5 is a driving timing diagram illustrating a method of driving a plasma display panel according to the present invention.

FIG. 6 is a timing diagram showing driving signals in any one sub-field by the driving method of FIG. 5.

<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, ..., SF8 ... subfield, A1, ..., A8 ... address cycle,

S1, ..., S8 ... Diversion.

The driving method of the plasma display panel of the present invention for achieving the above object is a driving method in which the reset, address and sustain-discharge steps are sequentially performed in sub-field units for time division gray scale display. In the reset step, the state of the discharge space in the plasma display panel is initialized. In the address step, a discharge cell selected from among the discharge cells is selected by a display data signal applied to address electrode lines of the plasma display panel and a scan signal applied to Y electrode lines arranged orthogonally to the address electrode lines. Wall charges are formed in the field. In the sustain-discharge step, sustain-discharge pulses are periodically applied to X and Y electrode lines arranged in parallel with each other to cause sustain-discharge in the discharge cells in which the wall charges are formed. Here, the pulse width of the scan signal applied in the address step and the corresponding display data signal is inversely proportional to the execution time of the sustain-discharge step in the previous sub-field.

According to the driving method of the present invention, it is possible not to be influenced by the sustain-discharge cycle in the previous sub-field without extending the overall driving time. Accordingly, the address discharge characteristic in each sub-field becomes uniform, so that the image quality can be improved.

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

Referring to FIG. 5, a unit frame is divided into eight subfields SF1,..., SF8 to realize time division gray scale display. Further, each subfield SF1, ..., SF8 is divided into address periods A1, ..., A8 and sustain discharge periods S1, ..., S8.

In each address period A1, ..., A8, 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.

Here, the pulse widths of the scan signal and the corresponding display data signal applied in each address period A1, ..., A8 are equal to the sustain-discharge periods S1, ..., S8 in the previous sub-field. Inversely Therefore, each address period A1, ..., A8 is also inversely proportional to the sustain-discharge periods S1, ..., S8 in the previous sub-field. That is, the conditional expression of A2> A3> A4A5> A6> A7> A8> A1 is applied.

In each sustain discharge period (S1, ..., S8), 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, causing 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, ..., S8 occupy in the unit frame. The lengths of the sustain discharge cycles S1, ..., S8 occupy a unit frame are 255T (T is the unit time). Therefore, it can be displayed in 256 gray levels, including the case where it is not displayed once in a unit frame.

Here, the time 1T corresponding to 2 ⁰ in the sustain discharge period S1 of the first subfield SF1 and the time corresponding to 2 ¹ in the sustain discharge period S2 of the second subfield SF2 2T) is, the third time (4T) corresponding to include ²² sustain discharge period (S3) of the subfield (SF3) is the fourth, the sustain discharge period (S4) of the subfield (SF4) corresponding to ²³ The time 8T corresponds to 2 ⁴ in the sustain discharge period S5 of the fifth subfield SF5, and the time 16T corresponds to 2 ⁵ in the sustain discharge period S6 of the sixth subfield SF6. The corresponding time 32T corresponds to the time 64T corresponding to 2 ⁶ in the sustain discharge period S7 of the seventh subfield SF7, and the sustain discharge period S8 of the eighth subfield SF8. Times 128T corresponding to 2 ⁷ are set respectively.

Accordingly, when the subfield to be displayed among the 8 subfields is appropriately selected, it can be seen that display of 256 gray levels can be performed including all zero (zero) gray levels that are not displayed in any of the subfields.

As mentioned above, according to the driving method according to the present invention, the pulse width of the scan signal and corresponding display data signal applied in each address period A1, ..., A8 is maintained in the previous sub-field. -Inversely proportional to the discharge cycle (S1, ..., S8). In other words, each address period A1, ..., A8 is also inversely proportional to the sustain-discharge periods S1, ..., S8 in the previous sub-field. That is, the conditional expression of A2> A3> A4> A5> A6> A7> A8> A1 is applied. Therefore, according to the driving method of the present invention, it is possible to be free from the sustain-discharge cycle in the previous sub-field without extending the overall driving time. Accordingly, the address discharge characteristic in each of the sub-fields SF1, ..., SF8 becomes uniform, so that image quality can be improved.

FIG. 6 shows driving signals in any one sub-field by the driving method of FIG. 5.

In FIG. 6, reference numeral S _A denotes a drive signal applied to each address electrode line (A _R1 , A _G1 ,..., A _Gm , A _Bm of FIG. 1), and S _x denotes X electrode lines (FIG. 1). X ₁ , ..., X _n ) drive signal applied to, and S _Y1 , ..., S _Yn is applied to each Y electrode line (Y ₁ , ..., Y _{n in} FIG. 1) Point to a signal. Referring to FIG. 5, the address period A in the unit sub-field SF is divided into a reset period A1, A2, A3 and a main address period A4.

In the display discharge period S, the voltage V higher than the positive polarity voltage V _{XB in} all the Y electrode lines Y ₁ , ..., Y _n and the X electrode lines X ₁ , ..., X _n . A common pulse of _S is applied alternately, causing display discharge in the discharge-cells in which wall charges are formed in the corresponding address period A. FIG. In this display discharge period S, when the last pulse is applied to the X electrode lines X ₁ ,..., X _n , electrons are around the X electrode of the selected and displayed discharge-cells, and around the Y electrode. Positive charges are formed. Accordingly, in the first reset period A1, a voltage V _RX lower than the positive voltage V _XB is applied to the X electrode lines X ₁ ,..., X _n , so that a discharge for first erasing the wall charges is generated. Is performed. In addition, in the second reset period A2, a narrow pulse of voltage V _S is applied to all of the Y electrode lines Y ₁ ,..., Y _n to perform discharge to secondly erase remaining wall charges. do. In the third reset period A3, the voltage V _RX is applied again to the X electrode lines X ₁ ,..., X _n to perform a discharge for finally erasing wall charges. Accordingly, all the wall charges can be erased and the space charges can be uniformly distributed in the discharge space.

In the main address period A4, the display data signal is applied to the address electrode lines A _R1 , A _G1 , ..., A _Gm , A _Bm and at the same time, each Y electrode line Y ₁ , ..., Y scan pulses corresponding to _n ) are applied sequentially. The display data signal applied to each of the address electrode lines A _R1 , A _G1 , ..., A _Gm , A _Bm has a positive polarity Va when the discharge-cell is selected, and a ground voltage of 0 [otherwise. V] is applied. The bias voltage V _YB is applied to each of the Y electrode lines Y ₁ ,..., And Y _n at a time not being scanned, and 0 [V] is applied at the time of being scanned. Accordingly, when the display data signal of voltage Va is applied while the scan pulse of 0 [V] 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. . Here, for more accurate and efficient address discharge, the voltage V _XB lower than the voltage V _S and higher than V _YB is applied to the X electrode lines X ₁ ,..., X _n .

As mentioned above, the pulse width T _A of the scan signal and the corresponding display data signal applied in the main address period A4 is the sustain-discharge period S1, ..., S8 in the previous sub-field. Inversely proportional to Thus, it is possible to be free from the sustain-discharge cycle in the previous sub-field without extending the overall driving time. Accordingly, since the address discharge characteristic in each sub-field SF is always uniform, the image quality can be improved.

As described above, according to the driving method of the plasma display panel according to the present invention, it is possible not to be influenced by the sustain-discharge cycle in the previous sub-field without extending the overall driving time. Accordingly, the address discharge characteristic in each sub-field becomes uniform, so that the image quality can be improved.

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.

Claims (1)

Reset, address, and sustain-discharge steps are sequentially performed in sub-field units for time division gray scale display, and in the reset step, the state of the discharge space in the plasma display panel is initialized, and in the address step, Wall charges are formed in the discharge cells selected from among the discharge cells by the display data signal applied to the address electrode lines and the scan signal applied to the Y electrode lines arranged perpendicular to the address electrode lines. In the discharge step, the driving method of the plasma display panel in which the sustain-discharge pulses are periodically applied to the X and Y electrode lines arranged in parallel to each other in order to cause sustain-discharge in the discharge cells in which the wall charges are formed , And the pulse width of the scan signal applied in the address step and the corresponding display data signal is inversely proportional to the execution time of the sustain-discharge step in a previous sub-field.