KR100634695B1 - Driving Apparatus and Method for Plasma Display Panel - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus and method for driving a plasma display panel by dividing a used gray scale and a non-graded gray scale in consideration of discharge characteristics. There is.

The driving device of the plasma display panel according to the present invention is a driving device of the plasma display panel which expresses an image in a frame composed of a combination of a plurality of subfields, the subfield according to the weight of all subfields as frame data input from the outside. A subfield mapping code generator for generating a mapping code and a subfield mapping code generated by the subfield mapping code generator generate data values of a predetermined number of subfields from the lowest weighted subfields among the plurality of subfields of the frame. A data determination unit for judging, a use gradation determination unit for dividing the use gradation and a non-use gradation with data values determined by the data determination unit, and a subfield mapping unit for subfield mapping the image data according to the use gradation separated by the use gradation determination unit; Characterized in that.

Plasma display panel, gradation, subfield, gradation used, gradation not used

Description

Driving apparatus and method for plasma display panel {Driving Apparatus and Method for Plasma Display Panel}

1 is a diagram showing the structure of a typical plasma display panel.

2 is a view showing a driving waveform of a conventional plasma display panel.

3 is a diagram illustrating a method of implementing image gradation of a conventional plasma display panel.

4 is a view for explaining a gray value selection method in a conventional method for driving a plasma display panel;

5 is a view for explaining a driving device of the plasma display panel of the present invention;

6A to 6B are views for explaining an embodiment of a method of driving a plasma display panel of the present invention.

7A to 7B are views for explaining still another embodiment of a method of driving a plasma display panel of the present invention.

<Explanation of symbols for the main parts of the drawings>

500: APL calculation unit 501: image correction unit

502: subfield mapping unit 503: data alignment unit

504: Timing controller 505: Data driver

506: scan driver 507: sustain driver

508: panel 509: data judgment unit

510: use gradation determination unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a plasma display panel driving apparatus and a method for driving a plasma display panel by dividing a used gray scale and a non-graded gray scale in consideration of discharge characteristics. .

In general, a plasma display panel is a partition wall formed between a front panel and a rear panel to form one unit cell, and each cell includes neon (Ne), helium (He), or a mixture of neon and helium (Ne + He) and An inert gas containing the same main discharge gas and a small amount of xenon is 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 panel in which a plurality of sustain electrode pairs formed by pairing a scan electrode 102 and a sustain electrode 103 are arranged on a front glass 101 that is a display surface on which an image is displayed. The rear panel 110 on which the plurality of address electrodes 113 are 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 panel 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 panel 110 is arranged such 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 panel 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 driving waveform for driving the plasma display panel is shown in FIG. 2.

2 illustrates a driving waveform of a conventional plasma display panel.

As shown in Fig. 2, the plasma display panel erases the reset period for initializing all the cells, the address period for selecting the cells to be discharged, the sustain period for maintaining the discharge of the selected cells, and the wall charges in the discharged cells. It is divided into an erase period for driving.

In the reset period, the rising ramp waveform Ramp-up is applied to all the scan electrodes at the same time in the setup period. This rising ramp waveform causes weak dark discharge within the full discharge cells. By this setup discharge, positive wall charges are accumulated on the address electrode and the sustain electrode, and negative wall charges are accumulated on the scan electrode.

During the set-down period, after the rising ramp waveform is supplied, the falling ramp waveform (Ramp-down) starts to fall from the positive voltage lower than the peak voltage of the rising ramp waveform and falls to a specific voltage level below the ground (GND) level voltage. By generating a weak erase discharge in the inside, the wall charges excessively formed in the scan electrode are sufficiently erased. By this set-down discharge, wall charges such that the address discharge can stably occur remain uniformly in the cells.

In the address period, the negative scan pulses are sequentially applied to the scan electrodes, and the positive data pulses are applied to the address electrodes in synchronization with the scan pulses. As the voltage difference between the scan pulse and the data pulse and the wall voltage generated in the reset period are added, address discharge is generated in the discharge cell to which the data pulse is applied. In the cells selected by the address discharge, wall charges are formed such that a discharge can occur when the sustain voltage Vs is applied. The sustain electrode is supplied with a positive polarity voltage Vz during the set down period and the address period so as to reduce the voltage difference with the scan electrode so as to prevent mis-discharge with the scan electrode.

In the sustain period, a sustain pulse Su is applied to the scan electrode and the sustain electrodes alternately. In the cell selected by the address discharge, as the wall voltage and the sustain pulse in the cell are added, a sustain discharge, that is, a display discharge, occurs between the scan electrode and the sustain electrode every time the sustain pulse is applied.

After the sustain discharge is completed, in the erase period, a voltage of an erase ramp waveform Ramp-ers having a small pulse width and a low voltage level is supplied to the sustain electrode to erase the wall charge remaining in the cells of the full screen.

A method of implementing image gradation in a plasma display panel driven by such a driving waveform is shown in FIG. 3.

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

As shown in FIG. 3, 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 light emission times, and each subfield is again configured as a reset period (RPD) for initializing all cells. ) 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. 3, 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. In this way, since the sustain period is different in each subfield, the gray scale of the image is expressed by adjusting the sustain period of each subfield, that is, the number of sustain discharges.

An example of a method of selecting an image gray level in a conventional plasma display panel which implements the image gray level in this manner will be described with reference to FIG. 4.

FIG. 4 is a diagram for describing a gray value selection method in a conventional method of driving a plasma display panel.

As shown in FIG. 4, when one frame is driven by dividing a plurality of subfields as shown in FIG. 3, predetermined weights are set for each subfield, and sustain discharge is performed in the subfield period in which the weights are set. The desired image gradation is realized by generating. For example, as shown in FIG. 4, when the image gradation 8 is implemented, the sustain discharge is generated in the fourth subfield having a weight of 8, and when the gradation 4 is implemented, the sustain discharge is generated in the subfield having the weight of 4. Let's do it.

In the case of the image gradation 8 described above as an example, the sustain discharge is generated only in the fourth subfield, and in the case of the image gradation 4, the sustain discharge is generated only in the third subfield. As described above, when the discharge is generated alone in one subfield while the sustain discharge is not generated in the preceding subfield, the sustain discharge becomes unstable. This means that the sustain discharge is stabilized even after the sustain discharge is generated first by the relatively small amount of wall charges in the low gradation subfield, and the sustain discharge is generated in the later subfield having a large weight. Accordingly, there is a problem in that the discharge characteristics become unstable in the subfield in which the sustain discharge is generated alone, and the image quality of the plasma display panel is deteriorated.

In order to solve this problem, conventionally, in order to stabilize the sustain discharge which becomes unstable when the sustain discharge occurs only in a subfield having a relatively large weight after the sustain discharge does not occur in the preceding subfield having a low weight. In the subfield where the sustain discharge is generated alone, the pulse width of the scan pulse applied to the scan electrode Y in the address period of FIG. 3 is increased. In other words, in the subfield in which the sustain discharge occurs alone, the scan pulse width in the address period is increased to stabilize the sustain discharge in the sustain period. However, if the scan pulse width is increased in this manner, the address period becomes longer and the subsequent sustain period is shortened. Therefore, the sustain margin is reduced.

In order to solve this problem, the present invention provides a driving apparatus and method for a plasma display panel which prevents deterioration of image quality by driving a plasma display panel by dividing a used gray scale and a non-graded gray scale in consideration of discharge characteristics of a subfield. There is a purpose.

The driving device of the plasma display panel according to the present invention is a driving device of the plasma display panel which expresses an image in a frame composed of a combination of a plurality of subfields, the subfield according to the weight of all subfields as frame data input from the outside. A subfield mapping code generator for generating a mapping code and a subfield mapping code generated by the subfield mapping code generator generate data values of a predetermined number of subfields from the lowest weighted subfields among the plurality of subfields of the frame. A data determination unit for judging, a use gradation determination unit for dividing a use gray level and a non-use gray level with data values determined by the data determination unit, and a subfield mapping unit for subfield mapping image data according to the use gray level divided by the use gray level determination unit Characterized in that.

Here, the data determining unit may determine a data value of the lowest weighted subfield among the plurality of subfields of the frame.

The data determination unit may determine a data value from the lowest weighted subfield to the second subfield among the plurality of subfields of the frame.

In addition, the use gray level determining unit may classify the gray level as the use gray level when all data values of the subfields determined by the data determination unit are at a high level.

In addition, the driving method of the plasma display panel of the present invention for achieving the above object is a driving apparatus of a plasma display panel which expresses an image in a frame composed of a combination of a plurality of subfields, wherein all subfields are used as frame data input from the outside. The subfield mapping code generation step of generating a subfield mapping code according to the field weights and the subfield mapping code generated in the subfield mapping code generation step are performed by a predetermined number of subfields having the lowest weight among the plurality of subfields of the frame. Image data is subfielded according to a data determination step of determining a data value of a subfield, a use gray level determination step of dividing a used gray level from a non-used gray level using the data value determined at the data determination step, and a gray level used by the gray level determination unit. Subfield Mapping Step to Map Characterized in that it comprises a.

In the data determining step, the data value of the lowest weighted subfield among the plurality of subfields of the frame may be determined.

In the data determination step, the data value from the lowest weighted subfield to the second subfield among the plurality of subfields of the frame may be determined.

In the use gray level determination step, when the data values of the subfields determined in the data determination step are all at a high level, the corresponding gray level is divided into a use gray level.

Hereinafter, a driving apparatus and method of a plasma display panel of the present invention will be described in detail with reference to the accompanying drawings.

5 is a view for explaining a driving apparatus of the plasma display panel of the present invention.

As shown in FIG. 5, the driving apparatus of the plasma display panel according to the present invention includes a subfield mapping code generation unit 50, a data determination unit 51, and a use gray level setting unit 52.

The subfield mapping code generation unit 50 generates a subfield mapping code according to all subfield weights using frame data input from the outside.

The data determination unit 51 determines the data value of the predetermined number of subfields from the lowest weighted subfields among the plurality of subfields of the frame using the subfield mapping code generated by the subfield mapping code generation unit 50 described above. do.

The use gray level determining unit 510 distinguishes between use gray and non-use gray based on the data value determined by the data determination unit 509 described above.

The information about the usage gray divided by the usage gray determining unit 52 is transmitted to a subfield mapping unit (not shown), and the subfield mapping unit (not shown) subtracts the image data according to the information about the usage gray level. Field mapping.

Here, it is preferable that the data determination unit 51 determines the data value of the lowest weighted subfield among the plurality of subfields of the frame.

The data determination unit 51 may also determine the data value from the lowest weighted subfield to the second subfield among the plurality of subfields of the frame.

Thus, the gray level used by the gray level determination unit 52 and the gray level not to be used are distinguished according to the data value of the subfield determined by the data determination unit 51. Preferably, the use gray level determining unit 52 classifies the gray level as the use gray level when the data values of the subfields determined by the data determination unit 51 are all at a high level. For example, when the data value is applied in the first subfield of one frame, the corresponding gray level is determined as the use gray level, or when the data value is applied in the first and second subfields of one frame. The gradation is used as the gradation.

An example of the driving method of the plasma display panel performed by the driving apparatus of the plasma display panel will be described with reference to FIGS. 6A to 6B.

6A to 6B are views for explaining a method of driving the plasma display panel of the present invention.

First, referring to FIG. 6A, in the method of driving a plasma display panel of the present invention, first, a subfield mapping code including all gray levels is prepared, that is, a subfield mapping code according to weights of all subfields of one frame is prepared. In operation S60, it is determined whether the data value of the first subfield SF 1 is 0 (S61). That is, it is determined whether a data value is applied in the first subfield. On the contrary, if the data value of the first subfield is 1, that is, whether the data value is applied in the first subfield is determined.

As a result of the determination of step S61, when data is applied in the first subfield, the corresponding grayscale is set to the used grayscale (S62), and when data is not applied in the first subfield, the corresponding grayscale is not used. It is set to (S63).

Subsequently, a new subfield mapping code is generated according to the newly set use gray level by dividing the use gray level and the non-use gray level (S64).

Through this process, the subfield mapping code is generated to drive the plasma display panel to display an image.

An example of such a method will be described with reference to FIG. 6B.

Referring to FIG. 6B, when one frame is driven by dividing a plurality of subfields, a predetermined weight is set for each subfield, and a desired image gradation is generated by generating sustain discharge in the weighted subfield. Implement In addition, the image gradation level to which data is applied to the first subfield in one frame is set to use gradation, and the image gradation level to which data is not applied to the first subfield is set to unused gradation. For example, as shown in FIG. 6B, when implementing image gradation 13, sustain discharge is generated in the first subfield having a weight of 1, and sustain discharge is generated in the third subfield with a weight of 4, and Sustain discharge is generated in the fourth subfield of 8, resulting in a total of 13 gray levels. Since data is applied in the first subfield, that is, the first subfield, in the image level of 13 gradations, it is set to use gradation. That is, 13 gradations to which data is applied to the first subfield are set as used gradations. In other words, when the data value of the first subfield, that is, the first subfield is at a high level, the corresponding gray level is set as the used gray level.

However, in the case of the 14th gradation level, since sustain discharge is generated in the second subfield, the third subfield, and the fourth subfield to implement the gradation level 14, data is not applied to the first subfield, that is, the first subfield. Therefore, it is set to non-use gradation.

In this way, the gradation level 15 is set to use gradation, the gradation level 16 is set to non-use gradation, and the gradation level 17 is also set to use gradation.

In this way, by setting the gradation to which data is applied to the first subfield, that is, the first subfield, as the use gradation, only one other subfield is selected after the first subfield to generate a sustain discharge thereafter. The image quality is improved by stabilizing the sustain discharge in the subfield.

For example, when data is applied to the first subfield and subsequently data is applied to the seventh subfield, the sustain discharge in the subsequent seventh subfield is caused by the sustain sustain discharge in the first subfield. This stabilizes the image quality, thereby improving image quality without increasing the width of the scan pulse at the gradation level at which data is applied to the first subfield and the seventh subfield.

In the above, only the gradation level at which data is not applied to the first subfield, that is, the first subfield, is selected and set as unused gradation, but the subfield to which data is not applied to the first subfield is thus selected. In the case where all of them are set to unused gradations, there is a possibility that the number of unused gradations becomes relatively large, thereby reducing the gradation implementability of the image to be implemented. In order to solve this problem, there is a method of selecting a gray level for which data is not applied to the first or second subfields and selecting the gray level as an unused gray level. Looking at this method is the same as Figure 7a to 7b.

7A to 7B are views for explaining still another embodiment of a method of driving a plasma display panel of the present invention.

First, referring to FIG. 7A, in the method of driving a plasma display panel of the present invention, first, when a subfield mapping code including all gray levels is prepared (S70), the data value of the first subfield SF 1 is 0. Determine (S71). That is, it is determined whether a data value is applied in the first subfield. On the contrary, if the data value of the first subfield is 1, that is, whether the data value is applied in the first subfield is determined.

As a result of the determination in step S71, when data is not applied in the first subfield, the corresponding grayscale is set to an unused grayscale (S74), and when data is applied in the first subfield, the second subfield SF It is determined whether the data value of 2) is 0 (S72).

As a result of the determination of step S72, when data is not applied in the first subfield, the corresponding grayscale is set to an unused grayscale (S74), and when the data is applied in the first subfield, the corresponding grayscale is used as the used grayscale. Set (S73).

Subsequently, a new subfield mapping code is generated according to a newly set use gray level by dividing the use gray level and the non-use gray level (S75).

Through this process, the subfield mapping code is generated to drive the plasma display panel to display an image.

An example of such a method will be described with reference to FIG. 7B.

Referring to FIG. 7B, when one frame is driven by dividing a plurality of subfields, a predetermined weight is set for each subfield, and a desired image gradation is generated by generating sustain discharge in the weighted subfield. Implement In addition, the image gradation level in which data is applied to both the first subfield and the second subfield in one frame is set to use gradation, and data is stored in at least one of the first subfield and the second subfield. The image gradation level that is not applied is set to an unused gradation that is not used. For example, as shown in FIG. 7B, when implementing image gradation 11, sustain discharge is generated in a first subfield having a weight of 1, and sustain discharge is generated in a second subfield having a weight of 2, Sustain discharge is generated in the fourth subfield of 8 to generate a total of 11 gray levels. In this 11th gradation image level, since data is applied in both the first subfield, that is, the first subfield and the second subfield, that is, the second subfield, it is set to the use gray level. That is, the 11th gradation to which data is applied to both the first subfield and the second subfield is set as the use gradation. In other words, when the data value of the first subfield, that is, the first subfield and the data value of the second subfield, that is, the second subfield are both at the high level, the corresponding gray level is set as the usage gray level.

However, in the case of the 12th gradation level, since a sustain transition occurs in the third subfield and the fourth subfield to implement gradation level 12, data is not applied to the first subfield, that is, the first subfield and the second subfield. Therefore, it is set to non-use gradation.

In this way, the gradation level 13 is set to an unused gradation, the gradation level 14 is set to an unused gradation, and the gradation level 15 is set to a used gradation.

In this way, by setting the gray level to which data is applied to both the first subfield, that is, the first subfield and the second subfield, that is, the second subfield, as the use gray level, Even when only one other subfield is selected and sustain discharge occurs, the sustain discharge in the subsequent subfield is stabilized, and the image quality of the plasma display panel is improved without increasing the width of the scan pulse.

For example, when data is applied only in the seventh subfield in any one frame of eight subfields, since sustain discharge occurs in the seventh subfield alone, the sustain discharge in the seventh subfield becomes unstable. Although the image is deteriorated, in the present invention, thus, the sustain discharge becomes unstable so that the gradation which causes the deterioration of image quality is eliminated. That is, as in the previous example, data is applied in the first subfield, that is, sustain discharge occurs in the first subfield, without setting and using the gray level in which the sustain discharge occurs solely in the seventh subfield. Only the gradation to be used is set as the use gradation, or data is applied in both the first subfield and the second subfield, that is, only the gradation in which the sustain discharge occurs in both the first subfield and the second subfield is set as the use gradation.

This suppresses deterioration in image quality by preventing the sustain discharge from becoming unstable.

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 exemplary embodiments described above 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 foregoing detailed description, and the meaning and scope of the claims are as follows. 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 in detail above, the driving apparatus and method of the plasma display panel of the present invention have the effect of suppressing deterioration of the image quality of the plasma display panel by setting the gray level in which the sustain discharge is unstable to the unused gray level.

Claims (8)

A driving apparatus for a plasma display panel which expresses an image by a frame composed of a combination of a plurality of subfields, A subfield mapping code generation unit generating a subfield mapping code according to all subfield weights using frame data input from the outside; A data determination unit that determines a data value of a predetermined number of subfields from a subfield having the lowest weight among a plurality of subfields of the frame using the subfield mapping code generated by the subfield mapping code generator; A usage gray scale determining unit for distinguishing a gray level from a gray level using a data value determined by the data determination unit; And A subfield mapping unit for subfield mapping image data according to the use gray level divided by the use gray level determining unit Driving device for a plasma display panel comprising a. The method of claim 1, The data determination unit And determining the data value of the lowest weighted subfield among the plurality of subfields of the frame. The method of claim 1, The data determination unit And determining data values from the lowest weighted subfield to the second subfield among the plurality of subfields of the frame. The method according to any one of claims 1 to 3, The use tone determining unit And when the data values of the subfields determined by the data determination unit are all at a high level, corresponding grayscales are divided into used grayscales. A driving apparatus for a plasma display panel which expresses an image by a frame composed of a combination of a plurality of subfields, A subfield mapping code generation step of generating a subfield mapping code according to all subfield weights using frame data input from the outside; A data determination step of determining data values of a predetermined number of subfields from the lowest weighted subfields among a plurality of subfields of the frame using the subfield mapping code generated in the subfield mapping code generation step; A use gray level determining step of distinguishing between a use gray level and a non-use gray level by the data value determined in the data determination step; And A subfield mapping step of subfield mapping image data according to the use gray level divided by the use gray level determination unit; Method of driving a plasma display panel comprising a. The method of claim 5, wherein In the data determination step And determining the data value of the lowest weighted subfield among the plurality of subfields of the frame. The method of claim 5, wherein In the data determination step And determining data values from the lowest weighted subfield to the second subfield among the plurality of subfields of the frame. The method according to any one of claims 5 to 7, In the use gradation determination step, And when the data values of the subfields determined in the data determination step are all at a high level, the corresponding gray level is divided into a used gray level.

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