KR20070050297A - Plasma display device - Google Patents

Abstract

According to a feature of the plasma display device according to the present invention, a first electrode formed on the front panel and a first electrode driver for applying a driving waveform having a reset period, an address period, and a sustain period for driving the first electrode are provided. The driving waveform may be lowered with at least two different inclinations during the reset period, and thus finer gray levels may be expressed when an extra margin generated by shortening the set-down period is used for the sustain period. In addition, there is an effect of reducing the pseudo contour phenomenon, and when the margin is utilized in the address section, more scanning is possible in the address section, thereby making single scan easier. In addition, there is an effect that can provide a plasma display device that is controlled by a more efficient drive signal by configuring a variety of drive waveforms using the margin.

Plasma, PDP, Drive Waveform, Slope

Description

Plasma Display Device

1 is a view showing a driving waveform of a conventional plasma display device;

2 is a diagram illustrating a reset period of a conventional scan drive waveform;

3 is a view showing a first embodiment of a driving waveform according to the present invention;

4 is a diagram illustrating a slope range of a first waveform among driving waveforms according to the present invention;

5 is a view showing a second embodiment of a driving waveform according to the present invention;

6 is a diagram illustrating experimental results of a driving waveform of the plasma display device according to the present invention.

<Explanation of symbols on main parts of the drawings>

L1: conventional set down waveform L2: first waveform

L3: second waveform

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display apparatus, and more particularly, to a plasma display apparatus capable of shortening a setdown period during a reset period of a driving waveform to increase a margin of the entire driving waveform.

The plasma display device according to the related art is as follows.

FIG. 1 is a diagram illustrating a driving waveform of a conventional plasma display apparatus, and FIG. 2 is a diagram illustrating only a reset period of a scan driving waveform of a conventional plasma display apparatus.

In the conventional plasma display device, a surface discharge is generated by applying a scan waveform and a sustain waveform as shown in FIG. 1 to a scan electrode and a sustain electrode formed on a front panel.

The driving waveforms are divided into a reset period, an address period, and a sustain period.

In the reset period, the wall discharge inside the plasma display panel is adjusted to generate the next discharge well. In the address period, each electrode line is scanned to select a cell in which the counter discharge is to be generated in response to a data pulse applied to the address electrode. do.

In the sustain period, the cells in which the counter discharge is generated are continuously discharged to maintain light for a predetermined period of time.

In particular, Fig. 2 is a more detailed division of the reset period, which may be divided into a set up period and a set down period.

In the setup period (a), a ramp pulse is applied to the scan electrodes to form wall charges between the electrodes to maintain an electric field corresponding to the discharge start voltage. Accordingly, electrons, sustain electrodes, and address electrodes are formed on the scan electrodes. Accumulate cations in the.

In the set down period (b), a falling ramp pulse is applied to remove excessive wall charges formed on each electrode, and an electric field close to the discharge start voltage is formed between the address electrode and the scan electrode, and the sustain electrode and the scan electrode.

In the plasma display device configured as described above, in order to stably display light and to express various gray levels, sufficient sustain pulses need to be applied during the sustain period, and the address period is long to drive the single scan method. You must lose.

However, since the period allocated during one frame is generally 16.67 ms, the address period or the sustain period cannot be increased indefinitely. In addition, since the number of subfields during one frame can be allocated only as much as possible within the limited time, there is a problem in that the conventional plasma display driving waveforms cannot achieve more detailed gradation and image quality.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a plasma display device having a driving waveform which increases the margin of the remaining address period or the sustain period by reducing the period during which the reset waveform is applied.

According to a feature of the plasma display device according to the present invention for solving the above problems, a driving waveform having a first electrode formed on the front panel, a reset period for driving the first electrode, an address period, and a sustain period is applied. And a first electrode driver, wherein the driving waveform falls with at least two different inclinations during the reset period.

Here, the driving waveform has a slope of two stages.

In addition, the reset period is divided into a setup period and a setdown period, and the driving waveform has a slope of the second stage in the setdown period.

The driving waveform includes a first waveform having a first slope applied first and a second waveform having a second slope applied later.

Also, the first slope of the driving waveform is larger than the second slope.

Here, when the entire set down period is T, the first waveform is applied until a certain period between T / 4 and T / 2.

And, the first waveform is lowered starting from the sustain voltage.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a diagram showing a first embodiment of a driving waveform of the plasma display device according to the present invention, FIG. 4 is a diagram showing a slope range of the first waveform of the plasma display device according to the present invention, and FIG. A second embodiment of a driving waveform of the plasma display device according to the invention is shown, Figure 6 is a diagram showing the experimental results of the driving waveform of the plasma display device according to the present invention.

The plasma display device according to the present invention comprises a first electrode formed on the front panel and a first electrode driver for applying a driving waveform having a reset period, an address period, and a sustain period for driving the first electrode. The driving waveform is lowered with at least two different inclinations during the reset period.

The first electrode is a scan electrode to which a scan driving waveform is applied.

The reset period is divided into a setup period and a set down period (c + d).

In particular, the first embodiment of the plasma display device according to the present invention is characterized in that the driving waveform falls with a two-step slope in the set-down period of the reset period as shown in FIG.

While the falling waveform L1 falls in one slope in the set down period (c + d + e) of the conventional plasma display device, in the plasma display device according to the present invention, the falling waveform L1 falls in two steps during the set down period. .

That is, when the waveform applied during the set down period is divided based on the slope, it may be divided into a first waveform L2 and a second waveform L3.

The slope of the first waveform L2 is greater than the slope of the second waveform L3. In addition, the slope of the first waveform (L2) is configured to be larger than the conventional falling waveform (L1).

During the reset period, a weak discharge is generated in the set down period to appropriately erase wall charges so that the next discharge is well generated. The weak discharge does not occur in the initial portions (c, P1) of the set down period, and the set The discharge does not occur in the initial portion of the set down period because it occurs in the later portions d and P2 of the down period.

Therefore, since the initial portion of the set down period does not significantly affect discharge, the voltage of the initial portion is drastically reduced to shorten the set down period.

In this way, at the beginning of the set-down period (c), the voltage is rapidly reduced to a constant voltage, and then a waveform having a gentler slope is applied to reduce the voltage to the final base voltage.

In this case, when compared with the conventional driving waveform, when the first waveform L2 and the second waveform L3 are reduced to the final base voltage compared to the conventional waveform L1, the entire set down period is reduced, so that a constant margin e is obtained. This occurs.

In this way, the margin e generated during the set down period may be used for the remaining sustain period or the address period.

In the case of using the single scan driving method, since the length of the address period must be longer than that of the double scan method, the margin e can be allocated to the address period.

In addition, the number of subfields may be increased by collecting margins e generated for each subfield. By increasing the number of subfields, more detailed gradation can be expressed, thereby eliminating pseudo contouring.

In the plasma display device according to the present invention, since discharge occurs in the P2 region during the set down period, the first waveform and the second waveform must be properly distributed during the set down period.

In addition, the first waveform forms a waveform starting from the sustain voltage Vs and gradually decreasing. The sustain voltage is equal to the magnitude of the highest voltage of the sustain pulse.

The start voltage of the first waveform may vary depending on the characteristics of the waveform.

When the first waveform is applied with too steep slope, the margin (e) of the driving waveform may be increased, but the weak discharge section caused by the second waveform may be reduced so that mis-discharge may occur. False discharge can also occur.

To this end, referring to FIG. 4, the application range of the first waveform is T. If the length of the entire set down period is T, the first waveform is applied until a predetermined period between T / 4 and T / 2. do.

That is, the first waveform is applied from one time point at which a set down period starts to one time point between a time point (x section) that is 1/2 of a time point that is 1/4 of the entire set down period T.

If the slope is too large, there is a fear that false discharge occurs due to too rapid voltage decrease.

On the contrary, when applied to a time point of 1/2 or more of the entire set down period, the slope is gentler than that of the conventional set down waveform, so that a certain margin e cannot be left.

Therefore, as described above, the first waveform having a steeper slope than the second waveform or the conventional set-down waveform is applied for one point between the start of the set-down period and the quarter to 1/2 period of the entire set-down period. It is configured to shorten the length of the down period and take advantage of the margin period (e) generated thereby.

A second embodiment of the plasma display device according to the present invention will be described with reference to FIG.

The plasma display device according to the present invention comprises a first electrode formed on the front panel and a first electrode driver for applying a driving waveform having a reset period, an address period, and a sustain period for driving the first electrode. The driving waveform is lowered with three different slopes during the reset period.

The difference compared to the first embodiment is that the second embodiment according to the present invention is applied with a set down waveform in three steps.

A first waveform with the steepest slope is applied first, followed by a second waveform that maintains a constant voltage (zero slope), and finally a third waveform is applied to drop to the final base voltage.

The second waveform is not limited to zero slope, and a waveform having a gentler slope than the first waveform may be used.

The third waveform causes the slope to be more gentle than the second waveform.

Therefore, the slope of the first waveform should be greater than the other two waveforms.

In addition, the first waveform forms a waveform starting from the sustain voltage Vs and gradually decreasing. The sustain voltage is equal to the magnitude of the highest voltage of the sustain pulse.

Similarly to the first embodiment, looking at the application range of the first waveform (L11), if the length of the entire set down period is T, the first waveform is applied until a certain period between T / 4 and T / 2 It is characterized by.

That is, the first waveform L11 is applied from one time point at which the set down period starts to one time point between 1/2 time point and 1/4 time point of the entire set down period T.

As mentioned above, if the voltage is applied up to a quarter of the total set-down period, the voltage may be reduced by too steep slope, thereby causing a false discharge.

On the contrary, if applied to a time point of 1/2 or more of the entire set down period, a certain margin (i) cannot be left.

In the second embodiment according to the present invention as shown in FIG. 5, the entire set down period may be divided into three parts. That is, it is divided into a section f to which the first waveform L11 is applied, a section g to which the second waveform L12 is applied, and a section h to which the third waveform L13 is applied, Since the voltage drop with respect to time in the first waveform is higher than other sections, the overall set down period has a certain margin (i) as compared with the conventional art.

Accordingly, as described above, the slope of the second waveform L12 or the third waveform L13 or the conventional set down during one point between the start of the set down period and the quarter to 1/2 period of the entire set down period is as described above. The first waveform, which is more urgent than the waveform, is applied to shorten the length of the set-down period and take advantage of the margin period i generated thereby.

FIG. 6 is a diagram illustrating a result of outputting a result value on an oscilloscope screen by experimenting with a driving waveform of a plasma display device according to the present invention.

Referring to FIG. 6, it can be seen that the driving waveform set down period of the plasma display device according to the present invention is 100 ms, which is reduced by 20 ms compared with 120 ms of the conventional waveform per unit subfield.

Since the extra 20 ms is shortened for each subfield, in case of 12SF, 240 ms per unit frame can be shortened. The gray scale expression and the drive signal can be configured in a variety of ways such as applying an extra pulse to the shortened portion in the sustain period or the address period.

E1 and E2 show that the weak discharge occurs in the latter part of each set down period in the present invention and the conventional waveform.

In the first and second embodiments, set-down waveforms having two inclinations and three inclinations, respectively, have been described. Can be.

When allocating the margin (e or i) of the signal generated by the first and second embodiments to the address period, more electrode lines can be scanned, which makes the single scan smoother. have.

In addition, when the margin is allocated to the sustain period, the number of sustain pulses can be increased, thereby improving the overall luminance, and by increasing the subfields by collecting the extra margins, more various gray levels can be expressed. The contour phenomenon can also be reduced.

As described above, the plasma display device according to the present invention has been described with reference to the illustrated drawings. However, the present invention is not limited by the embodiments and drawings disclosed herein, and may be applied within a range in which technical thoughts are protected.

Plasma display device according to the present invention configured as described above when the extra margin generated by shortening the set-down period is used in the sustain period can be expressed more fine gray scale, thereby reducing the pseudo contour phenomenon In the case of utilizing the margin in the address section, more scanning is possible in the address section, thereby making single scan easier. In addition, there is an effect that can provide a plasma display device that is controlled by a more efficient drive signal by configuring a variety of drive waveforms using the margin.

Claims (14)

A first electrode formed on the front panel; And a first electrode driver for applying a driving waveform having a reset period, an address period, and a sustain period for driving the first electrode. And the driving waveform falls with at least two different inclinations during the reset period. The method of claim 1, And the driving waveform has two levels of inclination. The method of claim 2, The reset period is divided into a setup period and a setdown period, And wherein the driving waveform has the two-step slope in the set down period. The method of claim 3, wherein And the driving waveform comprises a first waveform having a first slope applied first and a second waveform having a second slope applied later. The method of claim 4, wherein The driving waveform is the plasma display device, characterized in that the first slope is greater than the second slope. The method of claim 5, If the total set down period is T, And the first waveform is applied for a predetermined period between T / 4 and T / 2. The method of claim 6, And the first waveform is lowered from the sustain voltage. The method of claim 1, The driving waveform has a three-stage slope. The method of claim 8, The reset period is divided into a setup period and a setdown period, And the driving waveform has the three-step slope in the set down period. The method of claim 9, The driving waveform includes a first waveform and a second waveform having a nonzero slope applied first; And a third waveform having a slope of zero. The method of claim 10, And wherein the driving waveform is larger than the slope of the second waveform. The method of claim 11, The driving waveform is plasma display apparatus, characterized in that the first waveform is applied first, the third waveform is applied, and then the second waveform is applied. The method of claim 12, If the total set down period is T, And the first waveform is applied for a predetermined period between T / 4 and T / 2. The method of claim 13, And the first waveform is lowered from the sustain voltage.

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