KR20060092024A - Driving device and method for plasma display panel - Google Patents

Abstract

The present invention relates to a driving apparatus and a driving method of a plasma display panel, and more particularly, to a driving apparatus and a method of a plasma display panel for correcting a load effect of a screen to be displayed.

In accordance with another aspect of the present invention, a driving method of a plasma display panel includes a load effect measuring step of measuring a luminance value according to an amount of an image signal having the same gray value being loaded on a screen; An average load level calculating step of obtaining a load level at which the luminance values are averaged; And a load effect correction step of correcting the number of sustain pulses for displaying the video signal to have the same luminance value as the average load level.

Description

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

1 illustrates a structure of a general plasma display panel.

2 is a diagram illustrating a method of implementing image grayscale of a conventional plasma display panel.

3 is a graph showing the relationship between the number of sustain pulses according to APL used in the driving apparatus of the conventional plasma display panel.

4A and 4B are diagrams for explaining a load effect of a conventional plasma display panel.

5 is a diagram illustrating a conventional method of correcting the number of sustain pulses.

6 is a block diagram schematically illustrating a method of correcting a load effect of a plasma display panel according to an embodiment of the present invention.

7 is a graph illustrating a load effect correction method according to an embodiment of the present invention.

8 is a diagram for describing a method of obtaining a luminance value of a plasma display panel according to an exemplary embodiment of the present invention.

9 is a diagram schematically illustrating a luminance value lookup table in which luminance values are stored according to an exemplary embodiment of the present invention.

10 is a view schematically showing a driving apparatus of a plasma display panel according to an embodiment of the present invention.

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

1010; A load effect measurer 1020; Average load level calculator

1030; A load effect corrector 1040; Luminance compensator

1050; The sustain pulse driver 1060; Luminance Value Lookup Table

The present invention relates to a driving apparatus and a driving method of a plasma display panel, and more particularly, to a driving apparatus and a method of a plasma display panel for correcting a load effect of a screen to be displayed.

In general, a plasma display panel (Plasma Display Panel) is a partition wall formed between the upper substrate and the lower substrate forms a unit cell, each of the neon (Ne), helium (He) or a mixture of neon and helium ( The main discharge gas such as Ne + He) and an inert gas containing a small amount of xenon are filled. When discharged by a high frequency voltage, the inert gas generates vacuum ultraviolet rays and emits phosphors formed between the partition walls to realize an image. Such a plasma display panel has a spotlight as a next generation display device because of its thin and light configuration.

1 illustrates a structure of a general plasma display panel.

As shown in FIG. 1, a plasma display panel includes a front substrate in which a plurality of sustain electrode pairs formed by pairing a scan electrode 102 and a sustain electrode 103 are formed on a front glass 101, which is a display surface on which an image is displayed. A rear substrate 110 having a plurality of address electrodes 113 arranged so as to intersect the plurality of sustain electrode pairs on the back glass 111 forming the back surface 100 and the rear surface is coupled in parallel with a predetermined distance therebetween. .

The front substrate 100 is made of a scan electrode 102 and a sustain electrode 103, that is, a transparent electrode (a) formed of a transparent ITO material and a metal material to mutually discharge and maintain light emission of the cells in one discharge cell. The scan electrode 102 and the sustain electrode 103 provided as the bus electrode b are included in pairs. The scan electrode 102 and the sustain electrode 103 are covered by one or more upper dielectric layers 104 that limit the discharge current and insulate the electrode pairs, and to facilitate the discharge conditions on the upper dielectric layer 104 top surface. A protective layer 105 on which magnesium oxide (MgO) is deposited is formed.

The rear substrate 110 is arranged in such a manner that a plurality of discharge spaces, that is, barrier ribs 112 of a stripe type (or well type) for forming discharge cells are maintained in parallel. In addition, a plurality of address electrodes 113 which perform address discharge to generate vacuum ultraviolet rays are arranged in parallel with the partition wall 112. On the upper side of the rear substrate 110, R, G, and B phosphors 114 which emit visible light for image display during address discharge are coated. A lower dielectric layer 115 is formed between the address electrode 113 and the phosphor 114 to protect the address electrode 113. A method of implementing image gradation in such a plasma display panel is shown in FIG. 2.

2 is a diagram illustrating a method of implementing image grayscale of a conventional plasma display panel.

As shown in FIG. 2, in the conventional method of expressing a gray level of a plasma display panel, a frame is divided into several subfields having different number of emission times, and each subfield is a reset period (RPD) for initializing all cells again. ) Is divided into an address period APD for selecting a cell to be discharged and a sustain period SPD for implementing gradation according to the number of discharges.

For example, when displaying an image with 256 gray levels, a frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields SF1 to SF8 as shown in FIG. 2, and eight subfields. Each of the SFs SF1 to SF8 is divided into a reset period, an address period, and a sustain period.

The reset period and the address period of each subfield are the same for each subfield. The address discharge for selecting the cell to be discharged is caused by the voltage difference between the address electrode and the transparent electrode which is the scan electrode. The sustain period is increased at a rate of 2 ⁿ ( ^where n = 0, 1, 2, 3, 4, 5, 6, 7) in each subfield.

3 is a graph showing the relationship between the number of sustain pulses according to APL used in the driving apparatus of the conventional plasma display panel. As shown in FIG. 3, the conventional plasma display panel driving apparatus includes an APL (Average Picture Level) unit and differently assigns the number of sustain pulses applied to the sustain period according to the APL value.

A typical plasma display panel displays image information by emitting light of cells by a sustain pulse alternately applied to a scan electrode and a sustain electrode. At this time, the applied sustain pulse is a high voltage of the voltage of 180V to 220V, the power consumption is large.

In order to reduce the power consumption, the driving apparatus of the conventional plasma display panel is configured such that the maximum number of sustain pulses is allocated to the sustain period at 20% APL or less, and the number of sustain pulses allocated to the sustain period at 20% APL or more is gradually reduced. do.

Accordingly, the power consumption of the plasma display panel gradually increases before 20% APL, but the power consumption of the plasma display panel remains constant after 20% APL.

4A and 4B are diagrams for explaining a load effect of a conventional plasma display panel. FIG. 4A is a graph illustrating luminance values according to the amount of image signals having the same gray scale values loaded on a screen, and FIG. 4B illustrates a phenomenon in which luminance decreases as a load increases in a plasma display panel.

As shown in FIGS. 4A and 4B, the conventional plasma display panel has a problem in that luminance decreases as load increases, that is, a load effect occurs. This is due to the characteristics of the driving circuit and the characteristics of the plasma display panel.

Accordingly, in the plasma display panel, a solarization phenomenon occurs such that the displayed screens are partially aggregated or the gray level is reversed. In order to solve the screen effect of the plasma display panel, a method of adjusting energy recovery time or correcting the number of sustain pulses has been conventionally used.

5 is a diagram illustrating a conventional method of correcting the number of sustain pulses. As shown in FIG. 5, the method of correcting the number of sustain pulses is a method of correcting the number of sustain pulses such that a luminance value having a small screen load is the same as a luminance value having a large screen load.

However, the above-described method suffers from a problem that the overall luminance decreases, and thus, the compensating process of increasing the number of sustain pulses must be performed to compensate for the decrease of the overall luminance. In this process, there is a problem that the luminance of the low gradation portion is distorted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and to provide a driving apparatus and a method for driving the plasma display panel which can suppress distortion caused by luminance correction by improving the driving apparatus and driving method of the plasma display panel. There is this.

Another object of the present invention is to provide a plasma display panel driving apparatus and a method capable of reducing a solarization phenomenon by improving the driving apparatus and driving method of the plasma display panel.

In addition, another object of the present invention is to provide a plasma display panel driving apparatus and a method for improving the gray scale linearity and gray scale expressing power of the plasma display panel.

In order to achieve the above object, the driving method of the plasma display panel of the present invention includes a load effect measuring step of measuring the luminance value according to the amount of the image signal having the same gray value is loaded on the screen; An average load level calculating step of obtaining a load level at which the luminance values are averaged; And a load effect correction step of correcting the number of sustain pulses for displaying the video signal to have the same luminance value as the average load level.

The calculating of the average load level may include summing luminance values according to respective load levels of the video signal and dividing the sum of the luminance values by the total number of load levels.

The load effect correction step of the present invention is characterized by reducing the number of sustain pulses when the load level of the video signal is lower than the average load level, and increasing the number of sustain pulses when the load level of the video signal is higher than the average load level.

The invention further includes a luminance compensation step of adding a predetermined number of sustain pulses to the number of sustain pulses of the video signal corrected in the load effect correction step.

The predetermined number of sustain pulses of the present invention is characterized by the same for the entire load level.

The luminance value of the present invention is characterized in that any one of the actual measured luminance value or the luminance value obtained by the interpolation method using the actual measured luminance value.

According to the present invention, the actual measured luminance value for the number of a sustain pulses is referred to as A, and the actual measured luminance value for the number of c sustain pulses is referred to as C, and the number of b sustain pulses to be obtained according to the interpolation method. When the luminance value of B is referred to as B, the luminance value B is represented by the following equation,

Characterized by satisfying.

In at least one of the load effect measurement step, the average load level calculation step, and the load effect correction step, the brightness value lookup table storing the brightness value is used.

The present invention is characterized in that the number of sustain pulses of a low gray level video signal having a small gray level value is corrected according to the luminance value.

According to another aspect of the present invention, there is provided a driving apparatus of a plasma display panel, comprising: a load effect measuring unit configured to measure a luminance value according to an amount of an image signal having a same gray value loaded on a screen; An average load level calculator for obtaining a load level at which the luminance values are averaged; And a load effect correction unit for correcting the number of sustain pulses for displaying the video signal to have the same luminance value as the average load level.

According to a feature of the invention, to compensate for the luminance value to compensate for the load effect, the correction to reduce or increase the number of sustain pulses so that the image signal has the same luminance value based on the luminance value of the average load level do. In this case, the luminance values used in the present invention are luminance values obtained by interpolation using real measured luminance values and actual measured luminance values according to the number of sustain pulses and the load level. In addition, the number of sustain pulses of the video signal in the low gradation region of the present invention is corrected by the above-described luminance values. As a result, distortion caused in luminance compensation of the plasma display panel can be suppressed, and solarization can be reduced. In addition, the gray scale linearity and gray scale expressing power of the displayed screen may be improved.

Hereinafter, with reference to the accompanying drawings, a specific embodiment according to the present invention will be described.

6 is a block diagram schematically illustrating a method of correcting a load effect of a plasma display panel according to an embodiment of the present invention. As shown in FIG. 6, the driving method of the plasma display panel according to the exemplary embodiment of the present invention corrects the load effect through the following steps.

First, in the load effect measurement step, the luminance value is measured according to the amount of the video signal having the same gray value loaded on the screen (600A).

As the amount loaded on the screen for an image signal having the same gradation value increases, the luminance value gradually decreases according to the load effect. Therefore, in an embodiment of the present invention, in order to correct the luminance value, the luminance value according to the load effect is first obtained.

Subsequently, in the average load level calculation step, the load level at which the luminance values are averaged is calculated (600B).

At this time, after setting the load level according to the load amount, the luminance values corresponding to each load level of the video signal are summed. By dividing the sum of the luminance values by the total number of load levels, an average load level at which the luminance values are averaged can be obtained.

Thereafter, in the load effect correction step, the number of sustain pulses for displaying the video signal is corrected to have the same luminance value as the average load level (600C).

In an embodiment of the present invention, when the load level of the video signal is lower than the average load level, the number of sustain pulses is reduced to have the same luminance value as the average load level in order to correct the load effect.

In addition, when the load level of the video signal is higher than the average load level, the number of sustain pulses is increased to have the same luminance value as the average load level.

Thereafter, the exemplary embodiment of the present invention may further include a luminance compensation step of adding a predetermined number of sustain pulses to the number of sustain pulses of the image signal corrected in the load effect correction step (600D).

That is, since the image signal corrected on the basis of the luminance value of the average load level is in a state where the luminance is lowered as a whole, it is possible to correct the increase in the overall luminance by adding a predetermined number of sustain pulses.

At this time, the predetermined number of sustain pulses is equally added to the entire load level regardless of the load level. The number of sustain pulses added does not exceed the number of sustain pulses reduced at the peak load.

7 is a graph illustrating a load effect correction method according to an embodiment of the present invention.

As shown in FIG. 7, a load effect correction method according to an embodiment of the present invention is to correct +/- luminance based on a luminance value of an average load level. Accordingly, in the luminance compensation step, the luminance step compensation may be less, and the occurrence of distortion in the displayed image may be reduced.

For example, when the luminance value level difference between peak white luminance and full white luminance is 200 cd / m ² , the peak white luminance is reduced by 200 cd / m ² based on the full white luminance. In the load effect correction step 600C according to an embodiment of the present invention, the peak white luminance may be reduced by 100 cd / m ² , which is a luminance value of the average load level.

In addition, the luminance value added for the peak white luminance compensation in the luminance compensation step 600D becomes 100 cd / m ² . As a result, when the luminance compensation is small, the difference in the compensation coefficient is small, thereby reducing the distortion caused by the compensation coefficient.

In at least one of the load effect measuring step 600A, the average load level calculating step 600B, or the load effect correcting step 600C according to an embodiment of the present invention, the luminance value according to the number of load levels and sustain pulses. Each step may be performed more efficiently using the luminance value lookup table in which the information is stored. A more detailed description thereof will be described with reference to FIGS. 8 and 9.

8 is a diagram for describing a method of obtaining a luminance value of a plasma display panel according to an exemplary embodiment of the present invention.

As shown in FIG. 8, the luminance value at a predetermined number of sustain pulses is measured and measured, and the luminance value at the number of sustain pulses between the measured luminance values is interpolated using the measured luminance value. Obtain At this time, the measured luminance value and the luminance value obtained by the interpolation method have the same load level.

For example, when the number of sustain pulses is 1, the measured luminance value is 1, when the number of sustain pulses is 3, the measured luminance value is 3.1, and when the number of sustain pulses is 2, the luminance value is X. In this case, X obtained by interpolation is 2.5 (X = (1 + 3.1) / 2 = 2.05). That is, the interpolation method according to an embodiment of the present invention satisfies Equation 1 below.

Here, each parameter of Equation 1 is defined as follows.

a is the number of a sustain pulses.

c is the number of c sustain pulses.

A is the actual measured luminance value for the number of a sustain pulses.

C is the actual measured luminance value for the number of c sustain pulses.

B is a luminance value for the number of b sustain pulses to be obtained according to the interpolation method of the exemplary embodiment of the present invention.

As described above, the luminance values A and E of the sustain pulse numbers C1 and C5 of FIG. C and D) are obtained by interpolation using the measured luminance values A and E. That is, according to Equation 1, the luminance values of B, C, and D may be obtained as shown in Equations 2 to 4 below.

Luminance value B = Luminance value A + (Luminance value E-Luminance value A) / (Sustain pulse number C5-Sustain pulse number C1)

Luminance value C = Luminance value B + (Luminance value E-Luminance value B) / (Sustain pulse number C5-Sustain pulse number C2)

Luminance value D = Luminance value C + (Luminance value E-Luminance value C) / (Sustain pulse number C5-Sustain pulse number C3)

As described above, in contrast to conventionally using the newly measured luminance values whenever the APL curve of the input image signal is changed, in one embodiment of the present invention, the luminance values measured by the interpolation method and the measured luminance values are used. Because the values are used, they do not need to be measured all over again, which makes them more efficient.

In addition, in one embodiment of the present invention, the number of sustain pulses of a low gray level video signal having a small gray level value is corrected according to any one of the measured luminance value and the luminance value obtained by the interpolation method, and the gray scale linearity at low gray level is corrected. And gradation expression. In this case, it is preferable to perform the correction of the low gray level image signal after the above-described luminance compensation step.

9 is a diagram schematically illustrating a luminance value lookup table in which luminance values are stored according to an exemplary embodiment of the present invention.

As shown in FIG. 9, in one embodiment of the present invention, a luminance value is obtained according to each load level and the number of each sustain pulse.

In this case, the luminance value may be obtained by real measurement or interpolation and is stored in the luminance value lookup table. In each step described above with reference to FIG. 6, load effect correction according to an embodiment of the present invention can be efficiently performed by using luminance value information of the lookup table shown in FIG. 9.

10 is a view schematically showing a driving apparatus of a plasma display panel according to an embodiment of the present invention.

As shown in FIG. 10, the driving apparatus of the plasma display panel according to the exemplary embodiment of the present invention includes a load effect measuring unit 1010, an average load level calculating unit 1020, a load effect correcting unit 1030, and a luminance compensating unit. 1040, a sustain pulse driver 1050, and a luminance value lookup table 1060.

The load effect measuring unit 1010 measures the luminance value according to the amount of image signals having the same gray value loaded on the screen.

As the amount loaded on the screen for an image signal having the same gradation value increases, the luminance value gradually decreases according to the load effect. Therefore, in one embodiment of the present invention, a load effect measuring unit is provided to correct the luminance value.

The average load level calculator 1020 calculates a load level at which the luminance values are averaged.

The load effect correction unit 1030 corrects the number of sustain pulses for displaying the video signal to have the same luminance value as the average load level.

The luminance compensator 1040 adds a predetermined number of sustain pulses to the number of sustain pulses of the image signal corrected by the load effect corrector 1030.

The sustain pulse driver 1050 applies a sustain pulse to the sustain electrode and the scan electrode (not shown) of the plasma display panel according to the determined number of sustain pulses.

In at least one of the load effect measuring unit 1010, the average load level calculating unit 1020, or the load effect correcting unit 1030 according to an embodiment of the present invention, the luminance value according to the number of load levels and sustain pulses. The operation of each unit may be performed more efficiently by using the luminance value lookup table 960 in which the information is stored.

Further, by providing a low gray level video signal corrector (not shown), the number of sustain pulses of the low gray level video signal having a small gray level value can be corrected, thereby improving gray scale linearity and gray level expressing power in low gray levels.

Such an operation characteristic of the driving apparatus of the plasma display panel according to the exemplary embodiment of the present invention has been sufficiently described through the driving method of the plasma display panel of FIGS. 6 to 8, and thus it will be omitted.

As a result, a screen capable of suppressing distortion due to luminance correction is realized.

As such, the technical configuration of the present invention described above can be understood by those skilled in the art that the present invention can 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 improves the driving device and driving method of the plasma display panel, thereby having an effect of suppressing distortion due to luminance correction.

In addition, by improving the driving apparatus and driving method of the plasma display panel, there is an effect that the solarization phenomenon can be reduced.

In addition, the gray scale linearity and gray scale expressing power of the plasma display panel can be improved.

Claims (18)

A load effect measuring step of measuring a luminance value according to an amount of an image signal having the same gray value being loaded on a screen; An average load level calculating step of obtaining a load level at which the luminance values are averaged; And A load effect correction step of correcting the number of sustain pulses for displaying the video signal to have the same luminance value as the average load level; Method of driving a plasma display panel comprising a. The method of claim 1, The average load level calculation step Summing luminance values according to load levels of the video signals; And dividing the sum of the luminance values by the total number of load levels. The method of claim 1, The load effect correction step The number of sustain pulses is decreased when the load level of the video signal is lower than the average load level, and the number of sustain pulses is increased when the load level of the video signal is higher than the average load level. The method according to any one of claims 1 to 3, And a luminance compensation step of adding a predetermined number of sustain pulses to the number of sustain pulses of the image signal corrected in the load effect correcting step. The method of claim 4, wherein And the predetermined number of sustain pulses is the same for all load levels. The method of claim 1, The luminance value is And a luminance value obtained by interpolation using the actual measured luminance value or the actual measured luminance value. The method of claim 6, The actual measured luminance value of the number of a sustain pulses is A. The actual measured luminance value of the number of c sustain pulses is called C. When the luminance value of the number of b sustain pulses to be obtained according to the interpolation method is B, Luminance value B is represented by the following equation,

Method of driving a plasma display panel, characterized in that to satisfy. The method of claim 6, And at least one of the load effect measurement step, the average load level calculation step, and the load effect correction step uses a luminance value lookup table in which the luminance value is stored. The method of claim 6, And a method for correcting the number of sustain pulses of a low gray level video signal having a small gray level value according to the luminance value. A load effect measuring unit which measures a luminance value according to an amount of the image signal having the same gray value being loaded on the screen; An average load level calculator for obtaining a load level at which the luminance values are averaged; And A load effect correction unit for correcting the number of sustain pulses for displaying the video signal to have the same luminance value as the average load level; Driving device for a plasma display panel comprising a. The method of claim 10, The average load level calculator And summing luminance values according to load levels of the video signals, and dividing the sum of the luminance values by the total number of load levels. The method of claim 10, The load effect corrector And the number of sustain pulses is decreased when the load level of the video signal is lower than the average load level, and the number of sustain pulses is increased when the load level of the video signal is higher than the average load level. The method according to any one of claims 10 or 12, And a luminance compensator configured to add a predetermined number of sustain pulses to the number of sustain pulses of the corrected video signal in the load effect corrector. The method of claim 13, And the predetermined number of sustain pulses is the same for all load levels. The method of claim 10, The luminance value is And a luminance value obtained by interpolation using the actual measured luminance value or the actual measured luminance value. The method of claim 15, The actual measured luminance value of the number of a sustain pulses is A. The actual measured luminance value of the number of c sustain pulses is called C. When the luminance value of the number of b sustain pulses to be obtained according to the interpolation method is B, Luminance value B is represented by the following equation,

Driving device of the plasma display panel, characterized in that satisfying the. The method of claim 15, And at least one of the load effect measurer, the average load level calculator, and the load effect corrector uses a luminance value lookup table in which the luminance values are stored. The method of claim 15, And a number of sustain pulses of a low gray level video signal having a small gray level value according to the luminance value.

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