KR20030090373A - Method of driving plasma display panel wherein initialization steps are effectively performed - Google Patents

Abstract

PURPOSE: A method for driving a plasma display panel in which initializing steps are performed efficiently is provided to perform a stable addressing operation and to increase display contrast. CONSTITUTION: According to the method, charge state of display cells to be driven become uniform in an initialization step. And wall charges of a voltage are formed in display cells to perform display-sustain discharge in an address step. And in a display-sustain step, a display-discharge is performed only in the display cells where the above wall charges are formed by applying an AC pulse to all display cells. The display-sustain step is performed in a unit sub field. A unit frame is divided into the first and the second sub fields at least and a time division gray display is performed by the number of pulses of the display-sustain step allocated to each sub field. The intensity of the discharge in the above display cells in the initialization step of the second sub field is weaker than that of the first sub field.

Description

Method of driving plasma display panel where initialization steps are effectively performed

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of driving a plasma display panel, and more particularly, to form wall charges of a predetermined voltage only in display cells to perform display-maintenance discharge. And a display-holding step of performing display-holding discharge only on display cells in which the wall charges are formed by applying an alternating current pulse to all display cells, in the unit subfield. It is about.

1 shows a structure of a conventional three-electrode surface discharge plasma display panel. FIG. 2 shows an example of one display cell of the panel of FIG. 1. 1 and 2, between the front and rear glass substrates 10 and 13 of the conventional 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, The partition 17 and the magnesium monoxide (MgO) layer 12 as a protective layer are provided.

The address electrode lines A _R1 , A _G1 ,..., A _Gm , A _Bm are formed in a predetermined pattern on the front side of the rear glass substrate 13. The lower dielectric layer 15 is entirely applied in front of the address electrode lines A _R1 , A _G1 ,..., A _Gm , A _Bm . In front of the lower dielectric layer 15, barrier ribs 17 are formed in a direction parallel to the address electrode lines A _R1 , A _G1 ,..., A _Gm , A _Bm . These partitions 17 function to partition the discharge area of each display cell and prevent optical cross talk between each display 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 back of the front glass substrate 10 to be orthogonal to each other. Each intersection sets a corresponding display cell. Each X electrode line (X ₁ , ..., X _n ) and each Y electrode line (Y ₁ , ..., Y _n ) is a transparent electrode line of a transparent conductive material such as indium tin oxide (ITO) or the like (FIG. 2). X _na , Y _na ) and a metal electrode line (X _nb , Y _nb of FIG. 2) for increasing conductivity are formed. The front dielectric layer 11 is formed by applying the entire surface to the rear of the X electrode lines X ₁ ,..., X _n and the Y electrode lines Y ₁ ..., Y _n . A protective layer 12 for protecting the panel 1 from a strong electric field, for example, a magnesium monoxide (MgO) layer, is formed by applying the entire surface to the back of the front dielectric layer 11. The plasma forming gas is sealed in the discharge space 14.

The driving method generally applied to such a plasma display panel is a method in which the initialization, address, and display-maintaining steps are sequentially performed in the unit sub-field. In the initialization step, the charge states of the display cells to be driven are made uniform. In the address step, the charge state of display cells to be selected and the charge state of display cells not to be selected are set. In the display-holding step, display-holding discharge is performed in the display cells to be selected. At this time, a plasma is formed from the plasma forming gas of the display cells performing display-holding discharge, and the fluorescent layer 16 of the display cells is excited by ultraviolet radiation from the plasma to generate light.

Here, since the unit sub-fields are included in the unit frame, the desired gray level can be displayed by the display-hold times of each sub-field.

Referring to FIG. 3, a typical driving device of the plasma display panel (1 of FIG. 1) may include an image processor 66, a controller 62, an address driver 63, an X driver 64, and a Y driver 65. Include. The image processing unit 66 converts an external analog image signal into a digital signal to convert an internal image signal, for example, 8 bits of red (R), green (G), and blue (B) image data, a clock signal, vertical and horizontal, respectively. Generate sync signals. The controller 62 generates driving control signals S _A , S _Y , and S _X according to an internal image signal from the image processor 66. The address driver 63 processes the address signal S _A among the driving control signals S _A , S _Y , and S _X from the controller 62 to generate a display data signal, and generates the generated display data signal. Applied to the address electrode lines. The X driving unit 64 processes the X driving control signal S _X among the driving control signals S _A , S _Y , and S _X from the control unit 62, and applies the X driving control signal S _X to the X electrode lines. The Y driver 65 processes the Y driving control signal S _Y among the driving control signals S _A , S _Y , and S _X from the controller 62, and applies the Y driving control signal S _Y to the Y electrode lines.

FIG. 4 shows a conventional address-display separation driving method for the Y electrode lines Y ₁ ,..., Y _n of the plasma display panel 1 of FIG. 1. Referring to FIG. 4, a unit frame is divided into eight subfields SF1,..., SF8 to realize time division gray scale display. Here, the idle time T _ID is proportional to the number of display cells performing display-maintenance discharge in the unit frame. For example, there is a pause time T _ID proportional to the load rate of the unit frame. Here, the load rate of the unit frame is a ratio of the number of display cells performing display-maintenance discharge in the unit frame with respect to the total number of display cells of the plasma display panel 1. The reason why the idle time T _ID is present is to protect the plasma display panel 1 from excessive driving power.

Each subfield SF1, ..., SF8 is divided into address periods A1, ..., A8 and display-hold periods S1, ..., S8.

In the initial time of each address period A1, ..., A8, an initialization step is performed to make the charge state of the display cells to be driven uniform. In the main address period following the progress of this initial time, the display data signal is applied to the address electrode lines (A _R1 , A _G1 , ..., A _Gm , A _{Bm in} FIG. 1) and at the same time each Y electrode line Y Scan pulses corresponding to ₁ , ..., Y _n ) are sequentially applied. 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 display-hold period S1, ..., S8, all Y electrode lines Y ₁ , ..., Y _n and all X electrode lines X ₁ , ..., X _n Pulses for display-holding discharge are alternately applied to cause display-holding discharge in discharge cells in which wall charges are formed in corresponding address periods A1, ..., A8. Therefore, the luminance of the plasma display panel is proportional to the length of the display-hold periods S1, ..., S8 occupied in the unit frame. The length of the display-hold periods S1, ..., S8 occupying a unit frame is 255T (T is 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 display-hold period S1 of the first subfield SF1 corresponds to 2 ¹ in the display-hold period S2 of the second subfield SF2. Time 2T corresponds to 2 ² in the display-hold period S3 of the third subfield SF3 and ² in the display-hold period S4 of the fourth subfield SF4. ^The time 8T corresponding to ³ corresponds to the time 16T corresponding to 2 ⁴ in the display-hold period S5 of the fifth subfield SF5, and the display-hold period of the sixth subfield SF6. In S6), the time 32T corresponding to 2 ⁵ , the display-maintenance period S7 of the seventh subfield SF7 includes the time 64T corresponding to 2 ⁶ , and the time of the eighth subfield SF8. In the display-hold period S8, a time 128T corresponding to 2 ⁷ is 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.

In the conventional driving method of the plasma display panel as described above, conventionally, since the same driving method is used in all of the initialization steps of each address period A1, ..., A8, the discharge of discharges occurring in the display cells is eliminated. The intensity is the same in all of the initialization steps. Accordingly, there are the following problems.

First, when a weak discharge is performed in the initialization steps to increase the display contrast, less space charges are generated in the initialization steps when a low gray scale display is continued. Thus, the addressing operation in the main address steps becomes unstable.

Second, when strong discharge is performed in the initialization steps for a stable addressing operation, the display contrast is lowered.

An object of the present invention is to provide a method of driving a plasma display panel which can perform a stable addressing operation and can increase display contrast.

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

FIG. 2 is a cross-sectional view illustrating an example of one display cell of the panel of FIG. 1.

3 is a block diagram illustrating a conventional driving device of the plasma display panel of FIG. 1.

FIG. 4 is a timing diagram illustrating a conventional address-display separation driving method for Y electrode lines of the plasma display panel of FIG. 1.

FIG. 5 is a timing diagram showing driving signals according to the address-display separation driving method of the present invention.

FIG. 6 is a cross-sectional view illustrating a wall charge distribution of one display cell immediately after a gradual rising voltage is applied to all the Y electrode lines in the initialization cycle of FIG. 5.

FIG. 7 is a cross-sectional view illustrating a wall charge distribution of one display cell at the end of the initialization cycle 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 protective 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 _Bm ... address electrode line, X _na , Y _na ... transparent electrode line,

X _nb , Y _nb ... metal electrode line, 62 ... logical control,

63 ... address drive, 64 ... X drive,

65 ... Y drive unit, 66 ... image processing unit,

S _Y1 , ..., S _Yn ... Y electrode drive signal, S _X1..Xn ... X electrode drive signal,

S _AR1 .. _ABm ... display data signal, PR ... initialization cycle,

SF1, ..., SF8, SF _N , SF _{N + 1} ... Unit subfield, PA ... Main address period,

A1, ..., A8, A _N , A _{N + 1} ... address cycle, T _ID ... dwell time,

S1, ..., S8, S _N ... display-hold cycle, V _G ... ground voltage.

To achieve the above object, the present invention provides an initialization step of uniformizing the state of charge of display cells to be driven, an address step of causing wall charges of a predetermined voltage to be formed only in display cells to perform display-sustaining discharge, and all display cells. The display-holding step of performing display-holding discharge only in the display cells in which the wall charges are formed by applying an alternating pulse is performed in the unit subfield, and the unit frame is divided into at least first and second subfields. A method of driving a plasma display panel which performs time division gray scale display according to the number of pulses of the display-holding step assigned to each subfield. Here, the intensity of discharge occurring in the display cells in the initialization step of the second subfield is weaker than that of the first subfield.

According to the driving method of the present invention, since the intensity of discharge occurring in the display cells in the initialization step of the second subfield is weaker than that of the first subfield, the following effects are obtained.

First, since strong discharge occurs in the initialization steps of the first subfield and the additional subfields, the space charges in the initialization steps can be sufficiently generated even if the display of the low gray level is continued. Accordingly, subsequent addressing operations can be prevented from becoming unstable.

Second, since weak discharge occurs in the initialization steps of the second subfield and the additional subfields, the display contrast may be increased.

Preferably, the plasma display panel is arranged with alternating X electrode lines and Y electrode lines parallel to each other behind the front transparent substrate to form XY electrode line pairs, and the address electrode lines in front of the rear substrate are the XY electrode lines. It is a three-electrode structure arranged to intersect with respect to the pairs, in which display cells are set in the crossing regions. In addition, in the initialization of the second subfield, the voltage having the same polarity and a lower level is applied to the X electrode lines with respect to the voltages applied to the Y electrode lines. The intensity of the discharge occurring in the display cells is weaker than that of the first subfield.

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

4 and 5, the present invention provides an initialization step (PR) of uniformizing the state of charge of display cells to be driven, an address step of causing wall charges of a predetermined voltage to be formed only in display cells to be subjected to display-maintenance discharge. (PA), and display-hold steps (S1 to S8, S _N ) for performing display-hold discharge only on display cells in which the wall charges are formed by applying an alternating pulse to all display cells. To SF8, S _FN , and S _{FN + 1} , and the unit-frame is divided into at least first and second subfields S _FN and S _{FN + 1} and the display-maintenance period allocated to each subfield ( A method of driving a plasma display panel that performs time division gray scale display according to the number of pulses S1 to S8, S _N ).

Here, the intensity of discharge occurring in the display cells in the initialization step of the second subfield S _{FN + 1} is weaker than that of the first subfield.

As an example, the initialization period PR of the Nth subfield S _FN of FIG. 5 is applied to the first subfield SF1 of FIG. 4, and the initialization period PR of the N + _1th subfield S _{FN + 1 of} FIG. The initialization period PR may be applied to the second to eighth subfields SF2 to SF8 of FIG. 4. Accordingly, since weak discharge occurs in the initialization period S _{FN + 1 of} the second to eighth subfields SF2 to SF8, the display contrast may be increased. Here, when the low gray scale display is continued, many space charges may disappear immediately after the idle time T _ID . However, since a strong discharge occurs in the initialization period S _FN of the first subfield SF1 immediately after the idle time T _ID , the space charges may be sufficiently generated. Accordingly, subsequent addressing operations can be prevented from becoming unstable.

As another example, the initialization period PR of the Nth subfield S _FN of FIG. 5 is applied to the sixth subfield SF6 of FIG. 4, and the N + _1th subfield S _{FN + 1} is applied. The initialization period PR may be applied to the first to fifth subfields SF1 to SF5, the seventh and eighth subfields SF7 and SF8 of FIG. 4. Accordingly, since weak discharge occurs in the first to fifth subfields SF1 to SF5 and the seventh and eighth subfields SF7 and SF8, the display contrast may be increased. Here, when the display of the low gray level is continued, many space charges may disappear immediately after the fifth subfield SF5. However, since strong discharge occurs in the initialization period S _FN of the sixth subfield SF6 immediately after the fifth subfield SF5, the space charges may be sufficiently generated. Accordingly, subsequent addressing operations can be prevented from becoming unstable. Here, since the number of pulses of the display-hold period S6 allocated to the sixth subfield SF6 is relatively large, an effect of generating more space charges may be obtained.

In FIG. 5, reference numeral S _{AR1 ..ABm} denotes a driving signal applied to each address electrode line (A _R1 , A _G1 ,..., A _Gm , A _{Bm in} FIG. 1), and S _{X1 .. Xn} denotes an X electrode. The driving signal applied to the lines (X ₁ , ... X _{n in} FIG. 1), and S _Y1 , ..., S _Yn are the respective Y electrode lines (Y ₁ , ... Y _{n in} FIG. 1). Indicates a drive signal applied to. FIG. 6 illustrates a wall charge distribution of one display cell at a point in time after a gradual rising voltage is applied to the Y electrode lines Y ₁ ,... Y _n in the initialization period PR of FIG. 5. FIG. 7 illustrates a wall charge distribution of one display cell at the end of the initialization period PR of FIG. 5. 6 and 7 the same reference numerals as used in FIG. 2 indicate the object of the same function.

Referring to FIGS. 1 and 5, operations of the initialization period PR, the main address period PA, and the display-hold period S _{N of} the Nth subfield SF _N are described as follows.

In the initialization period PR of the Nth subfield S _{FN + 1} , first, the voltage applied to the X electrode lines X ₁ ,..., X _n is the first voltage (V) from the ground voltage V _G. V _S ), for example, continuously rising to 155 volts (V). Here, the ground voltage V _G is applied to the Y electrode lines Y ₁ ,..., Y _n and the address electrode lines A _R1 ,..., A _Bm . Accordingly, between the X electrode lines (X ₁ , ..., X _n ) and the Y electrode lines (Y ₁ , ..., Y _n ), and the X electrode lines (X ₁ , ..., X) A weak discharge occurs between _n ) and the address electrode lines A ₁ , ..., A _m , and negative wall charges are formed around the X electrode lines X ₁ , ..., X _n . .

Next, Y electrode lines (Y _1, ..., Y _n) the voltage is a first voltage applied to the (V _S), for example, a predetermined voltage than the first voltage (V _S) from 155 volt (V) The second voltage V _SET + V _{S which} is higher by (V _SET ) is continuously raised to, for example, 355 volts (V). Here, the ground voltage V _G is applied to the X electrode lines X ₁ ,..., X _n and the address electrode lines A _R1 ..., A _Bm . Accordingly, a discharge occurs between the Y electrode lines Y ₁ ,..., Y _n and the X electrode lines X ₁ ,..., X _n , while the Y electrode lines Y ₁ ,. .., Y _n ) and discharge also occur between the address electrode lines A _R1 ,..., A _Bm . Here, Y electrode lines _{(Y 1, ..., Y n} ) and the address electrode lines _{(A R1, ..., A Bm} ) than the discharge electrode line Y between the (Y _1, ..., Y _The reason why the discharge between _n ) and the X electrode lines (X ₁ , ..., X _n ) becomes stronger is that the negative wall charges around the X electrode lines (X ₁ , ..., X _n ) Because they were formed. Accordingly, many negative wall charges are formed around the Y electrode lines (Y ₁ , ..., Y _n ), and positive wall charges are formed around the X electrode lines (X ₁ , ..., X _n ). Are formed, and less positive wall charges are formed around the address electrode lines A _R1 , ..., A _Bm (see FIG. 6).

Here, the slope for continuously raising the voltage applied to the Y electrode lines (Y ₁ , ..., Y _n ) to the second voltage (V _SET + V _S ) is the number of total discharge cells in each subfield. And inversely proportional to the ratio of discharge cells to be displayed. That is, the end time t _BYP of the rising becomes inversely proportional to the ratio of discharge cells to be displayed to the total number of discharge cells in each subfield. Because the total capacitance of the plasma display panel is C (where C is proportional to the ratio of discharge cells to be displayed to the total number of discharge cells), and the total amount of current is i, it is applied to this capacitance C. This is because the voltage V is preferably set by Equation 1 below.

<Equation 1>

Next, in the state where the voltage applied to the X electrode lines X ₁ , ..., X _n is maintained at the first voltage V _S , the Y electrode lines Y ₁ , ..., Y _n The voltage applied to) is continuously lowered from the first voltage V _S to the ground voltage V _G. Here, the ground voltage V _G is applied to the address electrode lines A _R1 ,..., A _Bm . Accordingly, due to the weak discharge between the X electrode lines (X ₁ ,..., X _n ) and the Y electrode lines (Y ₁ , ..., Y _n ), the Y electrode lines (Y ₁ ,. Some of the negative wall charges around..., Y _n ) move around the X electrode lines X ₁ ,..., X _n (see FIG. 7). Further, the address electrode lines (A _R1, ..., A _Bm) is so applied with a ground voltage (V _G), the address electrode lines are positive wall charges around the (A _R1, ..., A _Bm) Slightly increased.

Thus, the in the subsequent main address period (PA), an address is applied to the display data signal to the electrode line, the second voltage (V _S) lower fourth voltage (V _SCAN) to bias the Y-electrode line than the (Y _As the scan signals of the ground voltage V _G are sequentially applied to ₁ , ..., Y _n ), smooth addressing may be performed. The display data signal applied to each of the address electrode lines A _R1 , ..., A _Bm is applied with the positive address voltage V _A when the display cell is selected and the ground voltage V _G when the display cell is not selected. do. Accordingly, when the display data signal of the positive address voltage V _A is applied while the scan pulse of the ground voltage V _G is applied, wall charges are formed by the address discharge in the corresponding display cell. Wall charges do not form. Here, the second voltage (V _S) on to the more accurate and efficient address discharge, the X electrode lines (X _1, ... X _n) applied.

In the following display-hold period S _N , the second voltage V _S is applied to all of the Y electrode lines Y ₁ , ... Y _n and the X electrode lines X ₁ , ... X _n . Display-hold pulses are alternately applied, causing discharge for display-hold in display cells in which wall charges are formed in the corresponding address period PA.

Next, with reference to Figures 1 and 5, the operation differences of the N-th sub-field initialization period (PR) of the N + 1 sub-field (SF _{N + 1)} for the initialization period (PR) of (SF _N) The explanation is as follows. For reference, operations of the main address period and the display-hold period of the _{N +} 1th subfield SF _{N + 1} are as described with respect to the Nth subfield SF _N.

The Y electrode lines (Y _1, ..., Y _n) the voltage is a first voltage applied to the (V _S), for example, a predetermined voltage (V _SET than the first voltage (V _S) from 155 volt (V) X electrode lines X ₁ ,... From a point in time t _F at a time of continuous rise to a second voltage (V _SET + V _S ) that is as high as, for example, 355 volts (V). , X _n ) is continuously raised to the third voltage (V _BF ) lower than the first voltage (V _S ). Accordingly, a weak discharge can be induced between the Y electrode lines Y ₁ ,..., Y _n and the X electrode lines X ₁ ,..., X _n to increase the display contrast.

On the other hand, such a rising voltage can be directly supplied from the X driver (64 in FIG. 3). In addition, when the outputs of the X driver 64 are all electrically floating, that is, high impedance, the same effect can be obtained. That is, by turning off the upper and lower transistors of all output terminals of the X driver 64, the voltage applied to the X electrode lines X ₁ ,..., X _n is maintained until the third voltage V _BF . Is raised. Accordingly, the driving power can be relatively reduced. Here, the third voltage V _BF is determined by Equation 2 below.

<Equation 2>

V _BF = V _SET + V _S -V _F

In Equation 2, V _F indicates a voltage applied to the Y electrode lines (Y ₁ ,..., Y _n ) at the start of floating.

Here, in order for the voltage applied to the X electrode lines X ₁ ,..., X _n to be continuously increased to the third voltage V _BF by the electric floating, the starting point t _F of the floating is Y It must be within the rise time t _BYM to t _BYP of the voltage applied to the electrode lines Y ₁ , ..., Y _n . Here, as, Y electrode lines _{(Y 1, ..., Y n} ) voltage to the second voltage applied to the (V _SET + V _S) that is the time, the end time of each of the sub rising to reach the above It becomes faster in inverse proportion to the ratio of discharge cells to be displayed to the total number of discharge cells in the field. Therefore, the starting time point t _F of the plotting must also be fast in inverse proportion to the ratio of discharge cells to be displayed to the total number of discharge cells in each subfield. For this purpose, it is necessary to set the starting point t _F of the floating point when the voltage applied to the Y electrode lines Y ₁ ,..., Y _n reaches a predetermined set voltage V _F. . Here, the slope for continuously raising the voltage applied to the X electrode lines (X ₁ , ..., X _n ) to the third voltage (V _BF ) is Y electrode lines (Y ₁ , ..., Y _n ) is equal to the slope for continuously raising the voltage applied to the second voltage (V _SET + V _S ).

As described above, according to the driving method according to the present invention, the intensity of discharge occurring in the display cells in the initialization step of the second subfield SF _{N + 1} is that of the first subfield SF _N. Since it is weaker, it has the following effects.

First, since strong discharge occurs in the initialization steps of the first subfield SF _N and the additional subfields, the space charges in the initialization steps can be sufficiently generated even if the display of the low gray level is continued. Accordingly, subsequent addressing operations can be prevented from becoming unstable.

Second, since the weak discharge occurs in the initialization steps of the second subfield SF _{N + 1} and the additional subfields, the display contrast may be increased.

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 (9)

An initialization step of making the charge states of the display cells to be driven uniform, an address step of causing wall charges of a predetermined voltage to be formed only in the display cells to be subjected to the display-holding discharge, and the wall charges by The display-holding step of performing display-holding discharge only in the formed display cells is performed in the unit subfield, and the unit frame is divided into at least first and second subfields and is assigned to each subfield. A driving method of a plasma display panel which performs time division gray scale display by the number of pulses of a holding step, And wherein the intensity of discharge occurring in the display cells in the initializing of the second subfield is weaker than that of the first subfield. The method of claim 1, The plasma display panel, The X electrode lines and the Y electrode lines are arranged side by side alternately next to each other behind the front transparent substrate to form XY electrode line pairs, and in front of the rear substrate, the address electrode lines are arranged to intersect with respect to the XY electrode line pairs. Is a three-electrode structure in which display cells are set at intersection regions, In the initializing step of the second subfield, By applying a voltage having the same polarity and a lower level to the X electrode lines with respect to the voltages applied to the Y electrode lines, the intensity of discharge occurring in the display cells in the initialization step of the second subfield is increased. Weak driving method than that of subfield. The method of claim 2, wherein the initializing of the second subfield comprises: A first step of continuously increasing the voltages applied to the X electrode lines to a first voltage; While continuously increasing the voltage applied to the Y electrode lines to a second voltage higher than the first voltage, while continuously increasing the voltage applied to the X electrode lines to a third voltage lower than the first voltage. Second step; And A third step of continuously lowering the voltage applied to the Y electrode lines to a fourth voltage lower than the third voltage while maintaining the voltage applied to the X electrode lines as the first voltage; Way. The method of claim 3, wherein in the second step, And the voltages applied to the X electrode lines are continuously raised to the third voltage by the X electrode lines being electrically floating. The method of claim 3, wherein in the second step, A driving in which a slope for continuously raising the voltage applied to the Y electrode lines to a second voltage higher than the first voltage is changed in inverse proportion to the ratio of discharge cells to be displayed to the total number of discharge cells in each subfield. Way. The method of claim 5, wherein in the second step, And the voltages applied to the X electrode lines are continuously raised to the third voltage by the X electrode lines being electrically floating. The method of claim 6, wherein in the second step, As the X electrode lines are electrically floating when the voltage applied to the Y electrode lines reaches a predetermined voltage, the voltage applied to the X electrode lines is continuously raised to the third voltage. And the slope for changing the same as the slope for continuously raising the voltage applied to the Y electrode lines to a second voltage higher than the first voltage. The method of claim 3, wherein the initializing of the first subfield comprises: A first step of continuously increasing the voltages applied to the X electrode lines to a first voltage; A second voltage continuously increasing the voltage applied to the Y electrode lines to a second voltage higher than the first voltage, while maintaining the voltage applied to the X electrode lines at a fourth voltage lower than the third voltage; step; And A third step of continuously lowering the voltage applied to the Y electrode lines to a fourth voltage lower than the third voltage while maintaining the voltage applied to the X electrode lines as the first voltage; Way. The method of claim 8, wherein in the second step, A driving in which a slope for continuously raising the voltage applied to the Y electrode lines to a second voltage higher than the first voltage is changed in inverse proportion to the ratio of discharge cells to be displayed to the total number of discharge cells in each subfield Way.