KR100741119B1 - Method for driving discharge display panel according to cumulative drive time - Google Patents

Abstract

A method for driving a discharge display panel according to an accumulated driving time is provided to extend lifespan of a green phosphor layer by reducing colliding ions on the green phosphor layer. A unit frame of image data is divided into plural sub-fields. Each of the sub-fields is divided into reset, address, and sustain periods, such that a discharge display panel is driven according to the periods(S2). Sustain pulses are alternately supplied to the sustain and scan electrode lines during the sustain period. When an accumulated driving time of the discharge display panel exceeds a predetermined time(S3), a bias voltage level with the same polarity as the sustain pulses is supplied to green address electrode lines of the address electrode lines during the sustain period(S4).

Description

Method for driving discharge display panel according to cumulative drive time}

1 is a perspective view illustrating an internal structure of a three-electrode surface discharge plasma display panel as a discharge display panel driven by an embodiment of the present invention.

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

3 is a timing diagram illustrating a method of driving the plasma display panel of FIG. 1.

4 is a block diagram illustrating a driving apparatus of the plasma display panel of FIG. 1 according to an exemplary embodiment of the present invention.

5 is a flowchart illustrating a control algorithm of the logic controller of FIG. 4.

FIG. 6 is a waveform diagram illustrating driving signals used in any subfield of the unit frame of FIG. 3 when the accumulated driving time of the plasma display panel of FIG. 1 does not pass the set time.

FIG. 7 is a cross-sectional view illustrating a wall charge distribution of one discharge cell at time t ₅ of FIG. 6.

Figure 8 is a cross-sectional view of the one wall charge distribution of a discharge cell at the time t ₈ in FIG.

FIG. 9 is a waveform diagram illustrating driving signals used in any subfield of the unit frame of FIG. 3 when the cumulative driving time of the plasma display panel of FIG.

<Explanation of symbols for main parts of the drawings>

1 ... discharge 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 , ..., Xn ... X electrode line, Y ₁ , ..., Yn ... Y electrode line,

A _R1 , ..., A _Bm ... address electrode line, X _na , Y _na ... transparent electrode line,

X _nb , Y _nb ... metal electrode lines, SF1, ... SF8 ... subfield,

S _Y ... Y drive control signal, V _G ... ground potential,

S _X ... X drive control signal, S _A ... address drive control signal,

52 logic controller, 53 address drive,

54 ... X drive, 55 ... Y drive,

56 ... image processing unit, S ... reset cycle.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of driving a discharge display panel, and more particularly, having a front substrate and a rear substrate opposed to each other, wherein the sustain electrode lines and the scan electrode lines are alternately and side by side. And a method of driving a discharge display panel in which address electrode lines are formed to cross the storage electrode lines and the scan electrode lines.

In a typical discharge display device, for example, the plasma display device of US Pat. No. 5,541,618, a unit frame is divided into a plurality of subfields for time division gray scale display, and each of the subfields is a reset period, an addressing period, and a sustain period. It includes. Each of the subfields has a unique gray scale weight value, and a maintenance period is set in proportion to the gray scale weight value.

Meanwhile, the address electrode lines are divided into red address electrode lines, green address electrode lines, and blue address electrode lines. The red address electrode lines face the red fluorescent layer with a dielectric interposed therebetween. The green address electrode lines face the green fluorescent layer with a dielectric interposed therebetween. The blue address electrode lines face the blue fluorescent layer with a dielectric interposed therebetween.

Here, in the case of the green fluorescent layer, the durability of the impact of ions during discharge is relatively weak due to its characteristics, and the characteristic of the green fluorescent layer starts to deteriorate from one point in the cumulative driving time. Accordingly, the lifespan of the green fluorescent layer is shortened, and the balance between the display colors is gradually changed, thereby reducing the reproducibility of the display image.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of driving a discharge display panel which can increase the reproducibility of a display image by extending the life of the green fluorescent layer and maintaining a balance between display colors.

In order to achieve the above object, the present invention has a front substrate and a rear substrate spaced apart from each other, wherein sustain electrode lines and scan electrode lines are alternately and parallel to each other, and address electrode lines are formed on the sustain electrode. A driving method of a discharge display panel which is formed to cross the lines and the scan electrode lines, the method comprising a panel driving step and a bias applying step.

In the panel driving step, the unit frame of the image data is divided into a plurality of subfields, and each of the subfields is divided into a reset period, an addressing period, and a sustain period to drive the discharge display panel.

In the bias applying step, sustain pulses are alternately applied to the sustain electrode lines and the scan electrode lines in the sustain period. When the accumulated driving time of the discharge display panel has passed a set time, the sustain period is maintained in the sustain period. A bias potential of the same polarity as the pulses is applied to the green address electrode lines among the address electrode lines.

According to the driving method of the discharge display panel of the present invention, when the cumulative driving time of the discharge display panel passes a set time, among the ions due to the discharge between the sustain electrode lines and the scan electrode lines in the sustain period. Ions that collide with the green fluorescent layer facing the green address electrode lines are reduced.

As a result, the lifespan of the green fluorescent layer is extended and the balance between the display colors is maintained, thereby increasing the reproducibility of the display image.

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

FIG. 1 shows the structure of a three-electrode surface discharge plasma display panel 1 as a discharge display panel driven by an embodiment of the present invention. FIG. 2 shows an example of one discharge cell of the plasma display panel 1 of FIG. 1.

1 and 2, between the front and rear glass substrates 10 and 13 of the 3-electrode surface discharge plasma display panel 1 according to an embodiment of the present invention, the address electrode lines A _R1. A _Bm ), dielectric layers 11 and 15, X electrode lines X ₁ to X _n as sustain electrode lines, and Y electrode lines Y ₁ as scan electrode lines. To Y _n ), the phosphor 16, the partition 17, and the magnesium monoxide (MgO) layer 12 as a protective layer are provided.

Address electrode lines A _R1 To A _Bm ) are formed in a predetermined pattern on the front side of the rear glass substrate 13. Lower dielectric layer 15 has address electrode lines A _R1. To A _Bm ) in front of the entire surface. In front of the lower dielectric layer 15, barrier ribs 17 are formed in the address electrode lines A _R1. To A _Bm ). These partitions 17 function to partition the discharge area of each discharge cell and prevent optical cross talk between each discharge cell. The fluorescent layer 16 is applied between the partition walls 17.

X electrode lines X ₁ as sustain electrode lines To X _n and Y electrode lines Y ₁ as scan electrode lines To Y _n are the address electrode lines A _R1. To A _Bm ) are formed alternately and side by side at the rear of the front glass substrate 10 in a direction intersecting with. Each intersection sets a corresponding discharge cell. Each X electrode line (X ₁ To Xn) and each Y electrode line (Y _1). To Y _n ) is a combination of a transparent electrode line (X _na , Y _na of FIG. 3) of a transparent conductive material such as indium tin oxide (ITO), and a metal electrode line (X _nb , Y _nb of FIG. 2) to increase conductivity. It is formed. The front dielectric layer 11 has X electrode lines X _1. To X _n and the Y electrode lines Y _1. To Y _n ), the entire surface is applied and formed. 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.

In the driving method applied to such a discharge display panel, reset, addressing, and sustaining cycles are sequentially performed in the unit subfield. In the reset period, the charge states of all the discharge cells become uniform to suit the addressing period. In the addressing period, a predetermined wall potential is generated in the selected discharge cells. In the sustain period, a predetermined alternating voltage is applied to all the XY electrode line pairs, so that the discharge cells in which the wall potential is formed in the addressing period cause sustain discharge. In this sustain period, a plasma is formed in the discharge space 14 of the selected discharge cells causing the sustain discharge, that is, the gas layer, and the fluorescent layer 16 is excited by the ultraviolet radiation to generate light.

3 illustrates a method in which the plasma display panel 1 of FIG. 1 is driven. Referring to FIG. 3, each of the unit frames has eight subfields SF1 in the order of decreasing gray scale weight values in order to realize time division gray scale display. To SF8). In addition, each subfield SF1 To SF8 are reset periods R1. To R8), the addressing period A1 To A8), and the maintenance period S1 To S8).

The discharge conditions of all the discharge cells are each reset period R1. To R8) to be uniform and at the same time suitable for addressing to be performed in the next cycle.

Each addressing cycle (A1 From A8 to A8, the address electrode lines (A _{R1 in} FIG. 1). To A _Bm and a display data signal is applied to each Y electrode line Y _1. To Y _n ) are sequentially applied. Accordingly, when a high level display data signal is applied while the scan pulse is applied, wall potentials greater than or equal to the set value are formed by addressing discharge in the corresponding discharge cells, and wall potentials greater than or equal to the set value are not formed in the discharge cells that are not.

Each maintenance cycle (S1 To S8, all Y electrode lines Y _1. To Y _n ) and all X electrode lines (X ₁₎ To X _n ), the sustain pulse is alternately applied, so that the corresponding addressing period A1 To A8), display discharge is caused in the discharge cells in which wall potentials above the set value were formed. Therefore, the sustaining period S1 occupies the output luminance of one discharge cell in the unit frame. To the length of S8). In the present embodiment, the sustain period (S1) occupies in the unit frame To S8) is 255T (T is a unit period). Therefore, it can be displayed in 256 gray scales, even if it is not displayed once in a unit frame.

Here, the time 1T corresponding to 2 ⁰ corresponds to the sustain period S ₁ of the first subfield SF ₁ , and the time 1T corresponds to 2 ¹ to the sustain period S ₂ of the second subfield SF ₂ . In the holding period S ₃ of the third subfield SF ₃ , the time 2T is set to be a time 4T corresponding to 2 ² , and in the holding period S ₄ of the fourth subfield SF ₄ . A time period 8T corresponding to 2 ³ , a time period 16T corresponding to 2 ⁴ , and a sustain period of the sixth subfield SF ₆ are maintained in the sustain period S ₅ of the fifth subfield SF ₅ . S ₆ ) has a time 32T corresponding to 2 ⁵ , a holding period S ₇ of the seventh subfield SF ₇ has a time 64T corresponding to 2 ⁶ , and an eighth subfield SF _8. In the sustain period (S ₈ ) of), time 128T corresponding to 2 ⁷ is set, respectively.

Accordingly, eight subfields SF ₁ From SF ₈ ), if a subfield to be displayed is appropriately selected, display of 256 gray levels can be performed including all zero (zero) gray levels that are not displayed in any subfields.

Referring to FIG. 4, an apparatus for driving the plasma display panel 1 of FIG. 1 according to an exemplary embodiment of the present invention may include an image processor 56, a logic controller 52, an address driver 53, and an X driver 54. ), And the Y driver 55.

The image processing unit 56 converts an external analog image signal into a digital signal to convert an internal image signal, for example, 8-bit red (R), green (G), and blue (B) image data, a clock signal, vertical and horizontal, respectively. Generate sync signals.

The logic controller 52 generates driving control signals S _A , S _Y , and S _X according to an internal image signal from the image processor 56.

The address driver 53 generates the display data signal by processing the address signals S _A among the drive control signals S _A , S _Y , and S _X from the logic controller 52, and generates the displayed data. Signal to the address electrode lines (A _R1 of FIG. To A _Bm ).

The X driver 54 drives the control signal from the logic controller (52) (S _A, S _Y, S _X) from among the X driving control signal to the X electrode lines as a sustain electrode line according to the (S _X) (Fig. Drive ₁ X ₁ to X _n ).

The Y driver 55 includes _Y electrode lines as scan electrode lines according to the Y drive control signal S _Y among the drive control signals S _A , S _Y , and S _X from the logic controller 52 (FIG. 1). Y ₁ To Y _n ).

5 shows a control algorithm of the logic controller 52 of FIG. 4 and 5, the control algorithm of the logic controller 52 will be described.

When power is applied to the logic controller 52, the logic controller 52 turns on the internal accumulation timer to measure the cumulative driving time of the plasma display panel 1 (step S1).

Next, the logic controller 52 drives the plasma display panel 1 in accordance with the internal image signal from the image processor 56 (step S2). That is, the logic controller 52 generates the drive control signals S _A , S _Y , and S _X according to the internal image signal from the image processor 56, thereby causing the address driver 53, the X driver 54, and The Y driver 55 is operated.

On the other hand, when the driving time from the internal cumulative timer passes 1200 hours as the set time (by the reliability test) (step S3), the logic controller 52 controls the address driver 53 to maintain the maintenance periods. (S1 of FIG. 3 To S8), the bias potential of the same polarity as the sustain pulses is changed to the green address electrode lines (A _{G1 in} FIG. 1). To A _Gm ) (step S4).

Steps S2 to S4 are continued until an external end signal is generated (step S5).

When the end signal is generated, the logic controller 52 ends the driving of the plasma display panel 1 (step S6). That is, the logic controller 52 terminates the driving operation of the address driver 53, the X driver 54, and the Y driver 55. The logic controller 52 also turns off the internal cumulative timer (step S7).

According to the control algorithm of the logic controller 52 as described above, when the cumulative driving time of the plasma display panel 1 passes 1200 hours as the set time, the maintenance periods (S1 in FIG. 3). To S8) X electrode lines (X _{1 in} FIG. ₁₎ To X _n ) and the address electrode lines for green (A _{G1 in} FIG. 1) among the ions due to the discharge between the Y electrode lines (Y ₁ to Y _n in FIG. 1). Ions impinging on the green fluorescent layer facing to A _Gm ) are reduced.

As a result, the lifespan of the green fluorescent layer is extended and the balance between the display colors is maintained, thereby increasing the reproducibility of the display image. Techniques related to this are described in more detail below.

FIG. 6 illustrates driving signals used in one subfield SF of the unit frame of FIG. 3 when the cumulative driving time of the plasma display panel 1 of FIG. 1 does not pass the set time. In FIG. 6, reference numeral S _{AR1 ..ARm} denotes red address electrode lines (A _R1 of FIG. 1). To A _Rm ). S _{AG1 .. AGm} is the address electrode lines for green (A _{G1 in} FIG. To A _Gm ). S _{AB1 .. ABm} is the blue address electrode lines (A _B1 of FIG. 1). To A _Bm ). S _{X1 .. Xn} is X electrode lines (X ₁ of FIG. ₁₎ To X _n ). S _Y1 to S _Yn are each Y electrode line (Y ₁ of FIG. 1). To Y _n ). FIG. 7 shows the wall charge distribution of one discharge cell at time t ₅ of FIG. 6. Figure 8 shows one wall charge distribution of a discharge cell at the time point t ₈ in FIG. 7 and 8, the same reference numerals as used in FIG. 2 indicate the objects of the same function.

Referring to FIG. 6, the subfields SF1 of FIG. 3. In the reset period R of at least one of the subfields SF from SF8), in the wall charge accumulation periods t1 to t5, the potential applied to the Y electrode-lines Y ₁ to Y _n is increased. Positive first potential V _SET as the highest potential higher than ground potential V _{G by} the sixth potential V _SET higher than third potential V _S. + V _S ), for example, rises to 355 volts (V). X electrode-lines (X ₁ To X _n ) and address electrode-lines A _R1 To A _Bm ), the ground potential V _G is applied.

Accordingly, Y electrode-lines Y ₁ To Y _n ) and the X electrode-lines (X ₁₎ To X _n ), while discharge occurs between Y electrode-lines Y _1. To Y _n ) and address electrode-lines A _R1 To A _Bm ). Accordingly, all Y electrode-lines Y ₁ To Y _n ), negative wall charges accumulate and all X electrode-lines (X _1). To X _n ), positive wall charges are accumulated and all address electrode-lines A _R1. To A _Bm ), positive wall charges are accumulated (see FIG. 7).

Next, in the wall charge distribution period t5 to t8 of the reset period R, while the potential applied to the X electrode lines X ₁ to X _n is maintained at the fifth potential V _E , Y electrode-lines (Y ₁₎ To potential applied to Y _n is the first potential V _SET. From + V _S ) to the second negative potential V _SCL . Here, address electrode-lines A _R1 To A _Bm ), the ground potential V _G is applied. Accordingly, X electrode-lines X ₁ To X _n ) and the Y electrode-lines Y ₁ To due to the discharge between the Y _n), Y electrode lines (Y ₁ To Y _n ) some of the negative wall charges around move properly around the X electrode-lines X ₁ to X _n (see FIG. 8). In addition, address electrode-lines A _R1 To A _Bm , the ground potential V _G is applied, and therefore, the address electrode lines A _R1 To A _Bm ), the positive wall charges around them are appropriately reduced (see FIG. 8).

Thus, in the following addressing period A, the address electrode-lines A _R1 To A _Bm ), the display data signal is applied and the Y electrode-lines Y ₁ biased to the negative fourth potential V _SCH . To Y _n ), as the scan pulses of the negative second potential V _SCL are sequentially applied, smooth addressing may be performed. The display data signal applied to each of the address electrode lines A _R1 to A _{Bm is} supplied with the positive address potential V _A when the discharge cell is selected, and the ground potential V _G when the discharge cell is selected. Accordingly, when the display data signal of the positive address potential V _A is applied while the scan pulse of the second negative potential V _SCL is applied, appropriate wall potentials are formed by the address discharge in the corresponding discharge cell. In other discharge cells, no address discharge occurs. Here, for more accurate and efficient address discharge, X electrode-lines X ₁ To X _n ), the positive fifth potential V _E is applied.

In the sustain period S, all Y electrode-lines Y ₁ To Y _n ) and the X electrode-lines (X ₁₎ To X _n ), a sustain pulse of the positive third potential V _S is alternately applied, causing sustain discharge in discharge cells in which appropriate wall potentials are formed in the corresponding address period A. FIG. Here, all address electrode-lines A _R1 To A _Bm ), since the ground potential V _G is applied, activation of the sustain discharge can be enhanced.

FIG. 9 illustrates driving signals used in one subfield SF of the unit frame of FIG. 3 when the cumulative driving time of the plasma display panel 1 of FIG. 1 has passed a set time, for example, 1200 hours. Shows. In FIG. 9, the same reference numerals as used in FIG. 6 indicate objects of the same function.

The difference with respect to FIG. 6 of FIG. 9 is that in the sustain period S, the bias potential of the same polarity as the sustain pulses is equal to the address electrode lines A _R1. To A _Bm , the green address electrode lines A _G1 To A _Gm ). Green address electrode lines A _G1 To A _Gm ) has the same level as the potential V _A of the positive addressing pulse.

Therefore, when the cumulative driving time of the plasma display panel 1 passes the set time, the X electrode lines X ₁ in the sustain periods S are formed. To X _n and the Y electrode lines Y _1. To Y _n) of the ions from the address electrode lines for green due to the sustain discharge between (A _G1 Ions impinging on the green fluorescent layer facing to A _Gm ) are reduced.

As a result, the lifespan of the green fluorescent layer is extended and the balance between the display colors is maintained, thereby increasing the reproducibility of the display image.

Red address electrode lines A _R1 To A _Rm ) and the blue address electrode lines A _B1 to A _Bm are applied with a ground potential V _G regardless of the cumulative driving time to promote activation of sustain discharge.

As described above, according to the driving method of the discharge display panel according to the present invention, when the cumulative driving time of the discharge display panel passes the set time, due to the discharge between the sustain electrode lines and the scan electrode lines in the sustain period Among the ions, ions colliding with the green fluorescent layer facing the green address electrode lines are reduced. Accordingly, the lifespan of the green fluorescent layer is extended, and the balance between the display colors is maintained, thereby increasing the reproducibility of the display image.

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 (7)

A front substrate and a rear substrate spaced apart from each other, wherein sustain electrode lines and scan electrode lines are alternately and side-by-side formed between the substrates, and address electrode lines with respect to the sustain electrode lines and scan electrode lines In the driving method of the discharge display panel formed to cross, Dividing a unit frame of image data into a plurality of subfields, and dividing each of the subfields into a reset period, an addressing period, and a sustain period to drive the discharge display panel; And In the sustain period, sustain pulses are alternately applied to the sustain electrode lines and the scan electrode lines, and when a cumulative driving time of the discharge display panel has elapsed a predetermined time, the sustain pulses have the same polarity as the sustain pulses. And applying a bias potential to the green address electrode lines among the address electrode lines. The method of claim 1, And a positive bias potential is applied to the green address electrode lines in the sustain period when the cumulative driving time of the discharge display panel passes the set time. The method of claim 2, And a ground potential is applied to all of the address electrode lines in the sustain period if the accumulated driving time of the discharge display panel does not pass a set time. The method of claim 3, And the ground potential is applied to the red address electrode lines and the blue address electrode lines in the sustain period when the cumulative driving time of the discharge display panel elapses. The method of claim 2, wherein in the addressing period, A method of driving a discharge display panel in which a positive addressing pulse is applied to each of selected address electrode lines. The method of claim 5, And a level of the positive bias potential applied to the green address electrode lines and a level of the positive addressing pulse. The method of claim 5, wherein in the addressing period, A driving method of a discharge display panel in which negative scanning pulses are sequentially applied to each of the scan electrode lines.

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