KR100667239B1 - Device of Plasma Display Panel and Driving Method thereof - Google Patents

Abstract

The present invention relates to a plasma display panel driving apparatus and a driving method.

In the plasma display panel driving apparatus and driving method according to the present invention, an image is generated by applying a predetermined driving signal to a plurality of discharge cells by dividing a plurality of subfields into predetermined periods, where the odd number n of the discharge cells is n. = 1, 3, 5, ..) to the horizontal discharge cell lines by applying a predetermined drive signal by dividing the selective write subfield into a predetermined period, and even-numbered number (n = 2, 4, 6,. A predetermined driving signal is applied to the horizontally discharged cell lines by dividing the selective erasing subfield into predetermined periods.

Description

Plasma display panel driving device and driving method thereof {Device of Plasma Display Panel and Driving Method}

1 is a perspective view showing the structure of a conventional three-electrode AC surface discharge type PDP.

2 is a diagram showing a method of expressing image gradation of a conventional PDP.

3 is a view showing a method of driving a plasma display panel according to the prior art.

4 is a view illustrating a driving waveform according to the PDP driving method shown in FIG.

5 is a view showing a driving device of a plasma display panel according to the present invention;

6 is a view showing a method of driving a plasma display panel according to the present invention;

7 is a view illustrating a driving waveform for explaining a method of driving a plasma display panel according to the present invention;

***** Explanation of symbols for the main parts of the drawing *****

10: upper substrate 11: scanning / sustaining electrode

12: common sustain electrode 13a: upper dielectric layer

13b: lower dielectric layer 14: protective film

20: lower substrate 21: partition wall

22: address electrode 23: phosphor layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to an apparatus and method for driving a plasma display panel capable of improving gray scale display power of a plasma display panel.

In general, a plasma display panel (hereinafter referred to as "PDP") displays an image including a character or a graphic by emitting phosphors by 147 nm ultraviolet rays generated when a He + Xe or Ne + Xe inert mixed gas is discharged. Done.

1 is a perspective view showing the structure of a conventional three-electrode AC surface discharge type PDP. Referring to FIG. 1, the three-electrode AC surface discharge type PDP includes a scan / sustain electrode 11 and a common sustain electrode 12 formed on the upper substrate 10, and an address electrode formed on the lower substrate 20. 22). Each of the scan / sustain electrode 11 and the common sustain electrode 12 is formed of transparent electrodes 11a and 12a, for example, indium tin oxide (ITO). Each of the scan / sustain electrode 11 and the common sustain electrode 12 is formed with metal bus electrodes 11b and 12b for reducing resistance. An upper dielectric layer 13a and a passivation layer 14 are stacked on the upper substrate 10 having the scan / sustain electrode 11 and the common sustain electrode 12 formed thereon. Wall charges generated during plasma discharge are accumulated in the upper dielectric layer 13a. The protective layer 14 prevents damage to the upper dielectric layer 13a due to sputtering generated during plasma discharge, and increases emission efficiency of secondary electrons. As the protective film 14, magnesium oxide (MgO) is usually used.

Meanwhile, the lower dielectric layer 13b and the partition wall 21 are formed on the lower substrate 20 on which the address electrode 22 is formed, and the phosphor layer 23 is formed on the surfaces of the lower dielectric layer 13b and the partition wall 21. Is applied. The address electrode 22 is formed in the direction crossing the scan / sustain electrode 11a and the common sustain electrode 12a. The partition wall 21 is formed in parallel with the address electrode 22 to prevent ultraviolet rays and visible light generated by the discharge from leaking to the adjacent discharge cells. The phosphor layer 23 is excited by ultraviolet rays generated during plasma discharge to generate visible light of any one of red, green, and blue. An inert mixed gas such as He + Xe or Ne + Xe for discharging is injected into the discharge space of the discharge cells provided between the upper and lower substrates 10 and 20 and the partition wall 21. A method of expressing image gradation of a conventional PDP having such a structure will be described with reference to FIG. 2.

2 shows a method of expressing image gradation of a conventional PDP. As shown, the image gradation of the PDP is driven by dividing one frame into several subfields having different number of emission times. Each subfield is divided into a reset period for uniformly generating a discharge, an address period for selecting a discharge cell, and a sustain period for implementing gray levels according to the number of discharges. For example, when the image is to be displayed with 256 gray levels, the frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields. In addition, each of the eight subfields is divided into an address period and a sustain period. Here, the reset period and the address period of each subfield are the same for each subfield, while the sustain period is 2n (n = 0,1,2,3,4,5,6,7) in each subfield. Is increased.

Such a driving method of the PDP is roughly divided into a selective writing method and a selective erasing method according to whether or not the discharge cells are lighted up by the address discharge in the address period. First, the selective write driving method turns off the full screen in the reset period, and then turns on the discharge cells selected in the address period. Subsequently, in the sustain period, an image is displayed by sustaining discharge cells selected by the address discharge.

The selective erasing driving method turns on the full screen by writing discharge in the reset period, and then turns off the selected discharge cells in the address period. Subsequently, in the sustain period, an image is displayed by sustaining discharge cells not selected by the address discharge.

Since the selective erasing method is a discharge for removing wall charges in the cell, the scanning pulse width is narrower than that of the selective writing method, that is, the addressing time can be reduced.

On the other hand, the drive waveform of the selective writing method reduces the contrast as the number of lamp pulses increases, so that the more the use of the driving waveform, the lower the image quality.

Accordingly, in the driving method of the PDP, as shown in FIG. 3, one frame is composed of the selective write subfields SF1 to SF6 and the selective erase subfields SF7 to SF12 to form the selective write and erase method. Drive in parallel.

3 is a view showing a method of driving a plasma display panel according to the prior art. Referring to FIG. 3, in the method of driving a three-electrode alternating surface discharge PDP, one frame includes subfields SF1 through SF6 of selective writing and subfields SF7 through SF12 of selective erasing. The first to sixth subfields SF1 to SF6 include a reset period for turning off the full screen, an optional write address period for turning on the selected discharge cells, a sustain period for sustain discharge for the discharge cells selected by the address discharge, and erasing the sustain discharge. It is divided into an erasing period. In the first to sixth subfields SF1 to SF6, the selective write address period and the erase period are the same for each subfield, while the sustain period is 2 n (n = 0,1,2,3, 4,5). The seventh to twelfth subfields SF7 to SF12 have a selective erase address period for turning off selected discharge cells without a full surface writing period in which the full screen is lit, and a sustain period for sustaining discharge cells other than the discharge cells selected by address discharge. Divided into. In the seventh to twelfth subfields SF7 to SF12, not only the selective erasure address period but also the sustain period are set equally. The sustain period of the seventh to twelfth subfields SF7 to SF12 is set to a luminance relative ratio of 25 to have the same luminance relative ratio as that of the sixth subfield SF6.

Each of the seventh to twelfth subfields SF7 to SF12 driven by the selective erasing method must have the previous subfield turned on to turn off unnecessary discharge cells whenever the subfields are consecutive. For example, in order for the seventh subfield SF7 to be turned on, the sixth subfield SF6 driven by the selective write method, which is the previous subfield, must be turned on. After the sixth subfield SF6 is turned on, the unnecessary discharge cells are turned off in the seventh to twelfth subfields SF7 to SF12. For this purpose, in order for the selective erase subfield ESF to be used, cells turned on in the sixth subfield SF6 which is the last selective write subfield WSF must be turned on by sustain discharge. Therefore, the seventh subfield SF7 does not need a separate writing discharge for the selective erase address. In addition, the eighth to twelfth subfields SF8 to SF12 also selectively turn off the cells turned on in the previous subfield without front lighting.

4 is a diagram illustrating a driving waveform according to the PDP driving method illustrated in FIG. 3. Referring to FIG. 4, in the reset period of the selective write subfield SW, the reset pulse RP of the ramp-down waveform is sequentially followed by the reset pulse RP of the ramp-up waveform in the scan electrode lines Y. Supplied. The reset pulse (-RP) of this ramp down falls to the scan reference voltage (Vw) of negative polarity (-). In addition, a positive scan DC voltage DCSC is supplied to the sustain electrode lines Z.

In the address period of the selective write subfield SW, a negative polarity is applied to each of the scan electrode lines Y and the address electrode lines X while a positive scan DC voltage is supplied to the sustain electrode lines Z. A negative selective write scan pulse (-SWSP) and a positive polarity (+) selective write data pulse (SWDP) are supplied to be synchronized with each other. Sustain pulses SUSPy and SUSPz are alternately supplied to the scan electrode lines Y and the sustain electrode lines Z so that sustain discharge occurs for the cells turned on by the address discharge of the selective write subfield SW. . At the end of each selective write subfield SW, an erase pulse (not shown) is applied to the sustain electrode lines Z for the sustain discharge to be erased.

The reset period of the selective erase subfield SE is omitted. In the address period of the selective erasing subfield SE, the negative selective (-) of the selective erasing scan pulse (-SESP) and the positive polarity (T) for turning off a cell in each of the scan electrode lines Y and the address electrode lines X are applied. The selective erase data pulses SEDP of +) are supplied to be synchronized with each other. The selective erase scan pulse (-SESP) drops to the selective erase scan voltage (-Ve) higher than the scan reference voltage (-Vw). Sustain pulses SUSPy and SUSPz are alternately supplied to the scan electrode lines Y and the sustain electrode lines Z so that sustain discharge occurs for cells that are not turned off by the address discharge of the selective erase subfield SE. do. In the case where the next subfield is the selective erasure field SE, a sustain pulse SUSPy having a relatively large pulse width is supplied to the scan electrode lines Y at the end of the current selective erasure subfield SE. The erase pulse EP and the ramp signal RAMP are supplied to the scan electrode lines Y and the sustain electrode lines Z in the last selective erase subfield in which the next subfield is the selective write subfield SW. Eliminates sustain discharge in lit cells.

As described above, the plasma display panel driving method which combines the selective writing method and the selective erasing method in one frame can improve the image quality by merging the advantages of the selective writing method and the selective erasing method, but by increasing the number of subfields within a limited time, There is a limit to improving expressiveness.

Accordingly, an object of the present invention is to provide a plasma display panel driving apparatus and a driving method which can improve the gray scale expression by changing the plasma display panel driving method.

The driving apparatus and driving method of the plasma display panel according to the present invention for achieving the above object is to implement the image by applying a predetermined driving signal to a plurality of discharge cells by dividing a plurality of subfields into a predetermined period, the discharge The odd write (n = 1, 3, 5, ..) horizontal discharge cell lines are divided into a predetermined period to apply a predetermined driving signal to the horizontal discharge cell lines, and the even number (n = 2) of the discharge cells is applied. And a predetermined driving signal is applied to the fourth, sixth, sixth, ..) th horizontal discharge cell lines by dividing the selective erasing subfield into predetermined periods.

The period during which the first scan pulse is supplied among the predetermined periods of the selective write subfield is longer than the period during which the second scan pulse is supplied among the predetermined periods of the selective erase subfield.

In the predetermined period of the selective write subfield, the period in which the first scan pulse is supplied is 1.2 ms or more and 3.6 ms or less, and in the predetermined period of the selective erasure subfield, the period in which the second scan pulse is supplied is 1.1 ms or more and 3.0 ms or less. It is characterized by.

The voltage value of the second scan pulse is one of the same or higher than the voltage of the first scan pulse.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

5 is a view showing a driving device of a plasma display panel according to the present invention. Referring to FIG. 5, in the driving apparatus of the plasma display panel according to the present invention, m ㅧ n discharge cells 1 include scan electrode lines Y1 to Ym, sustain electrode lines Z1 to Zm, and data electrodes. PDP 100 arranged in a matrix so as to be connected to the lines X1 to Xn, a scan driver 102 for driving the scan electrode lines Y1 to Ym, and sustain electrode lines Z1 to Zm. ), And a sustain driver 104 for driving) and a data driver 106 for driving the address electrode lines X1 to Xn.

The scan driver 102 sequentially applies the scan pulses and the sustain pulses to the scan electrode lines Y1 to Ym so that the discharge cells 1 are sequentially scanned in line units, and m ㅧ n discharge cells are provided. (1) Let the discharge in each last. The sustain driver 104 applies a sustain pulse to all of the sustain electrode lines Z1 to Zm. The data driver 106 applies image data to the address electrode lines X1 to Xn in synchronization with the scan pulse.

Referring to the driving method of the plasma display panel according to the present invention having such a structure as follows.

6 is a view showing a driving method of the plasma display panel according to the present invention, Figure 7 is a driving waveform for explaining the driving method of the plasma display panel according to the present invention. 6 and 7, the method of driving the plasma display panel according to the present invention divides a plurality of subfields having different emission counts into predetermined periods and applies a predetermined driving signal to the plurality of discharge cells. The selective write subfield is divided into predetermined periods in the (n = 1, 3, 5, ..) th horizontal discharge cell lines, and a predetermined driving signal is applied to each period, and the even number (n = 2, 4) of the discharge cells is applied. The selective erasing subfield is divided into predetermined periods in the horizontal discharge cell lines, and a predetermined driving signal is applied to each of the periods. That is, the discharge cell lines are set by dividing the plurality of discharge cells formed in the plasma display panel in the row direction, and a drive signal of a selective write method is applied to the odd-numbered discharge cell lines among the discharge cell lines set in the row direction. In addition, a drive signal of a selective erase method is applied to even-numbered discharge cell lines among the discharge cell lines set in the row direction.

<Drive method of odd-numbered horizontal discharge cell line>

The selective write (SW) method in which the odd-numbered discharge cell lines are driven includes, as in the prior art, a reset period for turning off the full screen, an optional write address period for turning on selected discharge cells, a sustain period for maintaining discharge for the discharge cells selected in the address period, and The driving is divided into an erasing period for erasing the sustain discharge.

In the selective write (SW) subfield, during the reset period, the reset pulse RP of the ramp-up waveform is sequentially supplied to the scan electrode lines Y, followed by the reset pulse RP of the ramp-down waveform. The reset pulse (-RP) of this ramp down falls to the scan reference voltage (Vw) of negative polarity (-). At this time, the positive scan DC voltage DCSC is supplied to the sustain electrode lines Z.

In the subfield of the selective write (SW) method, each of the scan electrode lines Y and the address electrode lines X are supplied while the positive scan DC voltage DCSC is supplied to the sustain electrode lines Z during the address period. The negative write negative scan scan pulse (-SWSP) and the positive write positive pulse data (SWDP) are supplied to be synchronized with each other. In this case, the selective write scan pulse is referred to as 'first scan pulse' in the present invention. The first scan pulse is supplied to the scan electrode lines Y longer than the supply period of the second scan pulse supplied in the address period of the selective erase (SE) method described later. In other words, the even-numbered discharge cell lines driven by the selective erase (SE) method may further reduce the second scan pulse supply period, thereby securing a high driving margin. Therefore, it is possible to improve the gray scale expressing power of the entire plasma display panel by increasing the total number of subfields or increasing the number of sustain pulses in the sustain period. This reason is explained by the jitter phenomenon appearing in the address period. That is, when discharge occurs in the odd-numbered discharge cell lines during the address period, the next even-numbered discharge cell lines during the same address period receive the odd-numbered period of supply of the second scan pulse with the help of priming charges formed in the previous odd-numbered discharge cell lines. This is because sufficient discharge can be caused even shorter than the supply period of the first scan pulse supplied to the discharge cell line.

In addition, the voltage of the second scan pulse supplied to the scan electrode lines of the even-numbered discharge cell lines is supplied equal to the voltage value of the first scan pulse or is supplied at a higher voltage value. That is, the absolute voltage of the second scan pulse lower than the absolute voltage of the first scan pulse is supplied, thereby ensuring a high voltage margin. The reason for this is as described above and will be omitted.

On the other hand, the specific numerical limitation period for the supply period of the first scan pulse and the second scan pulse, that is, the period during which the first scan pulse is supplied to the scan electrode lines (Y) is preferably 1.2 kW or more and 3.6 kW or less At this time, it is preferable that the period during which the second scan pulse is supplied to the scan electrode lines Y is 1.1 ms or more and 3.0 ms or less. The threshold of 1.2 ms supply period of the first scan pulse is the minimum supply period for generating stable address discharge, and the 3.6 ms supply period is for securing a minimum driving margin for driving the plasma display panel. The threshold for the supply period of the second scan pulse is also the same reason.

 In the subfield of the selective write (SW) method, in the sustain period, the sustain pulses SUSPy and SUSPz generate the scan electrode lines Y and the sustain electrode lines Z such that sustain discharge occurs in the cells turned on by the discharge in the address period. Are alternately supplied. At the end of each selective write SW subfield SW, an erase pulse (not shown) is applied to the sustain electrode lines Z to cause the sustain discharge to be erased.

<Drive method of even-numbered horizontal discharge cell line>

 The selective erasure (SE) method in which the even-numbered discharge cell lines are driven is selected in the reset period for turning on the full screen by writing discharge, the address period for turning off the discharge cells by turning off the selected discharge cells, and the address period as in the prior art. Drives are divided into a sustain period for sustain discharge of undischarged discharge cells.

In the subfield of the selective erasure (SE) method, a predetermined signal supplied to the reset period, the address period, and the sustain period is almost the same as before. However, as described above, the supply period of the second scan pulse supplied to the scan electrode lines during the address period is shorter than the supply period of the first scan pulse supplied to the previous odd-numbered discharge cell line and the second scan pulse. The voltage of the pulse is also higher than the voltage value of the voltage of the first scan pulse as described above. Therefore, the even-numbered discharge cell lines driven by the selective erasing (SE) method can increase the number of subfields or increase the number of sustain pulses in the sustain period, thereby improving gray scale expression of the entire plasma display panel.

As described above, it will be understood by those skilled in the art that the above-described technical configuration may be implemented in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the detailed description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

As described above, the present invention can secure a high driving margin by varying the driving method for each discharge cell line of the plasma display panel, thereby improving the gray scale expression.

Claims (8)

A driving apparatus of a plasma display panel in which a plurality of subfields are divided into predetermined periods, and a predetermined driving signal is applied to the plurality of discharge cells to implement an image. The predetermined write subfield is divided into predetermined periods to apply a predetermined driving signal to odd-numbered horizontal discharge cell lines of the discharge cells (n = 1, 3, 5, ..), The plasma display panel is driven by applying a predetermined driving signal to the even-numbered horizontal discharge cell lines of the discharge cells by dividing the selective erasing subfield into predetermined periods of time (n = 2, 4, 6, ..). Device. The method of claim 1, The period during which the first scan pulse is supplied to the address period of the predetermined period of the selective write subfield is And a period longer than a period during which the second scan pulse is supplied in an address period of the predetermined erasing subfield. The method of claim 2, The period in which the first scan pulse is supplied in the address period of the predetermined period of the selective write subfield is 1.2 ms or more and 3.6 ms or less, And a period in which a second scan pulse is supplied in an address period of a predetermined period of the selective erasing subfield is 1.1 ms or more and 3.0 ms or less. The method of claim 2 or 3, And the voltage value of the second scan pulse is one of the same or higher than the voltage of the first scan pulse. A method of driving a plasma display panel in which a plurality of subfields are divided into predetermined periods, and a predetermined driving signal is applied to the plurality of discharge cells to implement an image. Applying a predetermined driving signal to an odd number (n = 1, 3, 5, ..) horizontal discharge cell lines by dividing an optional write subfield into predetermined periods of the discharge cells; Applying a predetermined driving signal to an even number (n = 2, 4, 6, ..) horizontal discharge cell lines by dividing the selective erasing subfield into a predetermined period of the discharge cells; Method of driving a plasma display panel comprising a. The method of claim 5, The period during which the first scan pulse is supplied to the address period of the predetermined period of the selective write subfield is And a period longer than a period during which a second scan pulse is supplied in an address period of the predetermined erasing subfield. The method of claim 6, The period in which the first scan pulse is supplied in the address period of the predetermined period of the selective write subfield is 1.2 ms or more and 3.6 ms or less, And a period in which a second scan pulse is supplied in an address period of a predetermined period of the selective erasing subfield is 1.1 ms or more and 3.0 ms or less. The method according to claim 6 or 7, And the voltage value of the second scan pulse is one of the same or higher than the voltage of the first scan pulse.

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