KR100590024B1 - A plasma display device and a driving method of the same - Google Patents

Abstract

The present invention relates to a plasma display device and a driving method thereof.

According to the display device of the present invention, an intermediate electrode is formed between the X electrode and the Y electrode to which the sustain discharge pulse voltage is applied. Then, a reset waveform and a scan pulse voltage are applied to the intermediate electrode.

According to the present invention, in the first sustain pulse section of the sustain discharge section, the intermediate electrode is biased to the first voltage, and the third electrode is floated during the subsequent sustain discharge pulse section. In the sustain discharge section, sustain discharge voltage pulses are alternately applied to the X electrode and the Y electrode.

Intermediate electrode, 4 electrode, address discharge, sustain discharge, floating

Description

Plasma display device and driving method thereof {A PLASMA DISPLAY DEVICE AND A DRIVING METHOD OF THE SAME}

1 is a perspective view of a conventional plasma display panel.

FIG. 2 is a cross-sectional view of the plasma display panel shown in FIG. 1.

3 is an electrode array diagram of a conventional plasma display device.

4 is a driving waveform diagram of a conventional plasma display device.

5 is an electrode array diagram of a plasma display device according to an exemplary embodiment of the present invention.

6 and 7 are a perspective view and a cross-sectional view of the plasma display panel according to an embodiment of the present invention, respectively.

8 is a driving waveform diagram of a plasma display device according to an exemplary embodiment of the present invention.

9A to 9E are wall charge distribution diagrams when the waveform shown in FIG. 8 is applied.

10 is a diagram illustrating a plasma display device according to an exemplary embodiment of the present invention.

FIG. 11 is a diagram illustrating the driving waveform shown in FIG. 9 in more detail.

12 is a driving waveform diagram of a plasma display device according to a second embodiment of the present invention.

FIG. 13 shows an equivalent circuit when the M electrode is floated. FIG.

14A and 14B are driving waveform diagrams of a plasma display device according to a third embodiment of the present invention.

FIG. 15 is a diagram illustrating in detail the configuration of a controller for supplying a driving waveform according to a fourth exemplary embodiment of the present invention.

16 and 17 are driving waveform diagrams of the plasma display device according to the fifth and sixth embodiments of the present invention.

The present invention relates to a plasma display device and a driving method thereof.

Recently, flat panel display devices such as liquid crystal displays (LCDs), field emission displays (FEDs), and plasma displays have been actively developed. Among these flat panel display devices, the plasma display device has advantages of higher luminance and luminous efficiency and a wider viewing angle than other flat panel display devices. Therefore, the plasma display device is in the spotlight as a display device to replace the conventional cathode ray tube (CRT) in a large display device of 40 inches or more.

Plasma display devices are flat display devices that display characters or images using plasma generated by gas discharge, and dozens to millions or more of pixels are arranged in a matrix form according to their size. The plasma display device is classified into a direct current type (DC type) and an alternating current type (AC type) according to the shape of a driving voltage waveform to be applied and the structure of a discharge cell.

In the DC plasma display device, since the electrode is exposed to the discharge space as it is, the current flows in the discharge space while the voltage is applied, and there is a disadvantage in that a resistance for current limitation must be made for this purpose. On the other hand, in the AC plasma display device, since the electrode covers the dielectric layer, the current is limited by the formation of a natural capacitance component, and thus the electrode is protected from the impact of ions during discharge.

1 is a partial perspective view of a conventional AC plasma display panel, and FIG. 2 is a cross-sectional view of the plasma display panel shown in FIG. 1.

1 and 2, the X electrode 3 and the Y electrode 4 covered with the dielectric layer 14 and the passivation layer 15 are arranged in parallel on the first glass substrate 11. At this time, the X electrode and the Y electrode is made of a transparent conductive material. Bus electrodes 6 made of metal materials are formed on the surfaces of the X and Y electrodes 3 and 4, respectively.

A plurality of address electrodes 5 are provided on the second glass substrate 12, and the address electrodes 5 are covered by the dielectric layer 14 '. A partition 17 is formed on the dielectric layer 14 ′ between the address electrodes 5 in parallel with the address electrode 5. In addition, phosphors 18 are formed on the surface of the dielectric layer 14 'and on both sides of the partition wall 17. The first glass substrate 11 and the second glass substrate 12 have a discharge space 19 therebetween so that the Y electrode 4 and the address electrode 5 and the X electrode 3 and the address electrode 5 are orthogonal to each other. Are placed opposite each other. The discharge space at the intersection of the address electrode 5 and the paired Y electrode 4 and the X electrode 3 forms a discharge cell 19.

3 shows an electrode arrangement diagram of a conventional plasma display device.

As shown in Fig. 3, the conventional plasma display electrode has a matrix configuration of m> n. The address electrodes A1 to Am are arranged in the column direction, and the n electrodes Y1 to Yn and the X electrodes X1 to Xn are arranged in a zigzag pattern in the row direction. The discharge cell 20 shown in FIG. 3 corresponds to the discharge cell 19 shown in FIG.

4 is a driving waveform diagram of a conventional plasma display device.

According to the driving method of the plasma display device shown in Fig. 4, each subfield is composed of a reset section, an address section, and a sustain section.

The reset section serves to erase the wall charge state of the previous sustain discharge and to set up wall charge in order to stably perform the next address discharge.

The address period is a period in which a wall charge is accumulated in a cell (addressed cell) that is turned on by selecting a cell that is turned on and a cell that is not turned on in the panel.

The sustain period is a period in which a sustain discharge voltage is alternately applied to the X electrode and the Y electrode to perform discharge for actually displaying an image on the addressed cell.

Hereinafter, the operation of the reset section of the conventional plasma display device driving method will be described in more detail. As shown in Fig. 4, the reset section is composed of an erase section, a Y ramp up section and a Y ramp down section.

(1) erasure interval (I)

During this period, a falling ramp that slowly descends from the sustain discharge voltage Vs to the ground potential is applied to the Y electrode while the X electrode is biased to a constant potential Vbias to remove the wall charges formed in the previous sustain period. .

(2) Y ramp up period (Ⅱ)

During this period, the address electrode and the X electrode are kept at 0 V, and a ramp voltage rising slowly from the voltage Vs toward the voltage Vset is applied to the Y electrode. While this ramp voltage is rising, weak reset discharge occurs in all discharge cells from the Y electrode to the address electrode and the X electrode, respectively. As a result, negative wall charges are accumulated at the Y electrode, and positive wall charges are accumulated at the address electrode and the X electrode at the same time.

(3) Y ramp descending section (Ⅲ)

Subsequently, in the second half of the reset period, while the X electrode is held at the constant voltage Vbias, a ramp voltage that gently falls from the voltage Vs toward the ground voltage is applied to the Y electrode. While this ramp voltage is falling, weak reset discharge occurs again in all the discharge cells.

However, according to the conventional plasma display device, the addressing operation from the first Y electrode to the last Y electrode is completed, and then the sustain discharge operation is simultaneously performed for all the discharge cells. Therefore, since there is not enough priming particles generated in the discharge cell when the first sustain discharge pulse is applied after the address period, there is a problem that discharge failure occurs.

In addition, according to the conventional plasma display device, since the waveform applied to the Y electrode (the waveform for reset and scan is additionally applied to the Y electrode) and the waveform applied to the X electrode are different from each other, The circuit for driving the circuit and the X electrode are different. Accordingly, the driving circuits of the X electrode and the Y electrode do not have impedance matching, so that waveforms alternately applied to the X electrode and the Y electrode in the sustain discharge period are distorted, thereby causing a problem of discharge failure.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the problems of the prior art, and to provide a plasma display device and a driving method thereof for preventing discharge failure.

A driving method of a plasma display device according to an aspect of the present invention for achieving the above object is

A driving method of a plasma display device comprising a first electrode and a second electrode to which a sustain discharge voltage pulse is applied, and a third electrode formed between the first electrode and the second electrode.

(a) biasing the third electrode to a first voltage during a first period and applying a sustain discharge voltage pulse to the first electrode or the second electrode; And

(b) floating the third electrode during the second period, and applying a sustain discharge voltage pulse to the first electrode and the second electrode alternately.

On the other hand, the driving method of the plasma display device according to another aspect of the present invention

A driving method of a plasma display device comprising a first electrode and a second electrode to which a sustain discharge voltage pulse is applied, and a third electrode formed between the first electrode and the second electrode.

(a) biasing the third electrode to a first voltage during a first period and applying a sustain discharge voltage pulse to the first electrode or the second electrode; And

(b) biasing the third electrode to a second voltage smaller than the first voltage during the second period, and applying sustain discharge voltage pulses to the first electrode and the second electrode alternately.

A driving method of a plasma display device according to another aspect of the present invention for achieving the above object is

A driving method of a plasma display device comprising a first electrode and a second electrode to which a sustain discharge voltage pulse is applied, and a third electrode formed between the first electrode and the second electrode, respectively.

determining whether the load ratio of the input image signal is a high load rate or a low load rate;

(b) when the determined load ratio is a high load ratio, floating the third electrode during a first period, and alternately applying a sustain discharge voltage pulse to the first electrode and the second electrode; And

(c) when the determined load ratio is a low load ratio, biasing the third electrode to a first voltage during the first period, and applying a sustain discharge voltage pulse to the first electrode and the second electrode alternately. Include.

A driving method of a plasma display device according to another aspect of the present invention for achieving the above object is

A driving method of a plasma display device comprising a plurality of first and second electrodes formed in a zigzag pattern, and a plurality of third electrodes formed between the first and second electrodes.

(a) biasing the first electrode to a first voltage;

(b) alternately applying a second voltage greater than the first voltage and a third voltage less than the first voltage to the second electrode; And

(c) applying a fourth voltage greater than the first voltage to the third electrode while the second voltage is applied to the second electrode; and applying the third voltage to the second electrode while the third voltage is applied. And applying a fifth voltage smaller than the first voltage to the electrode.

Plasma display device according to an aspect of the present invention for achieving the above object

A plasma display including an X electrode and a Y electrode to which sustain discharge voltage pulses are respectively applied, an intermediate electrode formed between the X electrode and the Y electrode, and an address electrode insulated from and intersecting the X electrode, the Y electrode and the M electrode; panel;

An address driver for applying a display data signal for selecting a discharge cell to the address electrode;

An X electrode driver and a Y electrode driver for applying sustain discharge voltage pulses for performing sustain discharge to the X electrode and the Y electrode, respectively;

An intermediate electrode driver configured to bias the intermediate electrode to a first voltage during a first period of the sustain discharge period, and to float the intermediate electrode during the second period; And

And a control unit for supplying a control signal to the address driver, the X electrode driver, the Y electrode driver, and the intermediate electrode driver.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

5 shows an electrode arrangement diagram of a plasma display device according to an embodiment of the present invention.

As shown in Fig. 5, in the plasma display device according to the embodiment of the present invention, the address electrodes A1 to Am are arranged in parallel in the column direction, and the Y electrodes Y1 to Y _n of n / 2 + 1 rows are arranged. _{/ 2 + 1} ), X electrodes (X1 to _{Xn / 2 + 1} ), and an intermediate electrode (hereinafter, referred to as 'M electrode') in an n row are arranged. That is, according to the embodiment of the present invention, the M electrode is arranged in the middle of the Y electrode and the X electrode, and the Y electrode, the X electrode, the M electrode, and the address electrode have a four-electrode structure in which one discharge cell 30 is formed. .

At this time, according to the embodiment of the present invention, the X electrode and the Y electrode mainly serve as an electrode for applying a sustain discharge voltage waveform, and the M electrode mainly serves for applying a reset waveform and a scan pulse voltage.

6 is a perspective view of a plasma display panel according to an embodiment of the present invention, and FIG. 7 is a cross-sectional view of the plasma display panel shown in FIG.

6 and 7, a plasma display panel according to an exemplary embodiment of the present invention includes a first substrate 41 and a second substrate 42. The X electrode 53 and the Y electrode 54 are formed on the first substrate 41. In addition, a bus electrode 46 is formed on the X electrode 53 and the Y electrode 53. The dielectric layer 44 and the passivation layer 45 are sequentially formed on the X and Y electrodes 53 and 54.

Meanwhile, an address electrode 55 is formed on the surface of the second substrate 42, and a dielectric layer 44 ′ is formed on the address electrode 55. The partition wall 47 is formed on the dielectric layer 44 ′ to form a cell 49 that is a discharge space between the partition walls 47. Phosphor 48 is applied to the surface of the partition wall 47 in the cell space between the partition walls 47. The X and Y electrodes 53 and 54 are formed at right angles to the address electrode 55.

In this case, according to the exemplary embodiment of the present invention, the intermediate electrode 56 is formed between the pair of X electrodes 53 and the Y electrodes 54 formed on the surface of the first substrate 41. As described above, a reset waveform and a scan waveform are mainly applied to this intermediate electrode. The bus electrode 46 is formed on the intermediate electrode 56.

The plasma display panel according to the exemplary embodiments of the present invention shown in FIGS. 5 to 7 has a structure in which intermediate electrodes are disposed between Xi and Y _i electrodes and between Y _i and X _{i +1} electrodes. That is, when there are n / 2 + 1 X electrode and Y electrode, the structure with n M electrodes is shown. However, the M electrode 56 may exist only between the X _i electrode 53 and the Y _i electrode 54, and there may be an electrode arrangement in which no M electrode exists between the Y _i electrode and the X _{i +1} electrode. In this case, the number of X electrodes, Y electrodes, and M electrodes is equal to n.

FIG. 8 is a driving waveform diagram of the plasma display device according to the first exemplary embodiment of the present invention, and FIGS. 9A to 9E are diagrams showing wall charge distribution according to the driving waveform shown in FIG.

Hereinafter, a driving method according to a first embodiment of the present invention will be described with reference to FIGS. 8 and 9A to 9E.

According to the driving method according to the first embodiment of the present invention shown in Fig. 8, each subfield is composed of a reset section, an address section, and a sustain section.

According to an exemplary embodiment of the present invention, the reset section includes an erasing section, an M electrode rising waveform section, and an M electrode falling waveform section.

(1-1) erasure interval (I)

This section serves to erase wall charges formed in the previous sustain discharge section. According to an embodiment of the present invention, it is assumed that the sustain discharge voltage pulse is applied to the X electrode at the last time of the sustain discharge period, and that a voltage lower than the voltage applied to the X electrode (eg, the ground voltage) is applied to the Y electrode. . Then, as shown in Fig. 9A, positive wall charges are formed on the Y electrode and the address electrode, and negative wall charges are formed on the X electrode and the M electrode.

In the erase period, a waveform (ramp waveform or log waveform) that gently falls from the voltage Vmc to the ground voltage is applied to the M electrode while the Y electrode is biased with the voltage Vyc. Then, the wall charges formed during the sustain discharge period are erased as shown in Fig. 7A.

(1-2) M electrode rising wave section (II)

During this period, a waveform (ramp waveform or log waveform) that rises slowly from the voltage Vmd to Vset is applied to the M electrode while the X electrode and the Y electrode are biased to the ground voltage. While this rising waveform is applied, weak reset discharges occur from the M electrodes to the address electrodes, the X electrodes, and the Y electrodes, respectively, in all the discharge cells. As a result, as shown in Fig. 9B, negative wall charges are accumulated at the M electrode, and positive wall charges are accumulated at the address electrode, the X electrode, and the Y electrode at the same time.

(1-3) M electrode falling waveform section (III)

Subsequently, in the second half of the reset period, while the X electrode and the Y electrode are biased at Vxe and Vye, waveforms (lamp waveforms or log waveforms) are gradually applied to the M electrodes from the voltage Vme to the ground voltage. At this time, it is preferable to set Vxe = Vye and Vmd = Vme in that the circuit configuration can be simplified, but is not necessarily limited thereto.

While this ramp voltage is falling, weak reset discharge occurs again in all the discharge cells. At this time, since the M electrode falling waveform section is for slowly decreasing the wall charges accumulated by the M electrode rising waveform section, the wall charge amount that is decreased as the time of the falling waveform is longer (that is, the slope is gentler) is precisely controlled. This is advantageous for address discharge.

As a result of applying the falling waveform to the M electrode, the wall charges accumulated on each electrode of all the cells are evenly erased. As shown in Fig. 9C, positive wall charges are accumulated on the address electrode, and at the same time, the X electrode and the Y electrode And negative wall charges are accumulated on the M electrode.

(2) Address section (scan section)

In the address period, scan pulses are sequentially applied to the M electrodes while the plurality of M electrodes are biased to the Vsc voltage, and a scan pulse is applied to the M electrodes. Apply an address voltage to the cell). At this time, the X electrode is maintained at the ground voltage, and the voltage Vye is applied to the Y electrode. (I.e., apply a voltage higher than the voltage of the X electrode to the Y electrode.)

Then, discharge occurs between the M electrode and the address electrode, and the discharge extends to the X electrode and the Y electrode. As a result, as shown in Fig. 9D, positive charges are accumulated on the X electrode and the M electrode, and Y Negative wall charges are stored in the electrodes and the address electrodes.

(3) maintenance discharge section

According to the sustain discharge section according to the embodiment of the present invention, the sustain discharge voltage pulse is alternately applied to the X electrode and the Y electrode while the M electrode is biased at the sustain discharge voltage Vm. The sustain discharge occurs in the discharge cells selected in the address section through the application of such a voltage.

At this time, according to the embodiment of the present invention, the discharge is caused by different discharge mechanisms at the initial and the normal time of the sustain discharge. For convenience of explanation, hereinafter, the discharge generated at the beginning of the sustain discharge is referred to as a short-gap discharge section, and the discharge at the normal time point is referred to as a long-gap discharge section.

(3-1) Short gap discharge section

In the start period of sustain discharge, as shown in Figs. 9E and 9B, a positive voltage pulse is applied to the X electrode and a negative voltage pulse is applied to the Y electrode (where, + and- Is a relative concept comparing the magnitude of the voltage applied to the X electrode and the voltage applied to the Y electrode, and the fact that + pulse voltage is applied to the X electrode means that a voltage greater than the Y electrode is applied to the X electrode. At the same time, a positive voltage pulse is applied to the M electrode. Therefore, unlike the conventional case where the discharge occurs only between the X electrode and the Y electrode, the discharge occurs between the X electrode / M electrode and the Y electrode. In particular, according to the embodiment of the present invention, since the distance between the M electrode and the Y electrode is closer than the distance between the X electrode and the Y electrode, the electric field applied between the M electrode and the Y electrode becomes larger. Therefore, the discharge between the M electrode and the Y electrode plays a dominant role than the discharge between the X electrode and the Y electrode. As described above, in the embodiment of the present invention, since the discharge between the M electrode and the Y electrode having a relatively short distance at the beginning of the sustain discharge plays a dominant role, it is called a short gap discharge.

As described above, according to the embodiment of the present invention, since a short gap discharge occurs by applying a relatively high electric field at the initial stage of sustain discharge, sufficient priming particles in the discharge cell are applied when the first sustain discharge pulse is applied after the address period. Even if it is not produced, sufficient discharge can be performed.

(3-2) Long gap discharge section

After application of the first sustain discharge pulse of sustain discharge, since the voltage of the M electrode is biased to a constant voltage (V _M ), the discharge between the M electrode and the X electrode or the discharge between the M electrode and the Y electrode (ie, a short gap discharge) ) Contributes little to the discharge, so that the main discharge becomes a discharge between the X electrode and the Y electrode, so that an image inputted by the number of discharge pulses applied alternately to the X electrode and the Y electrode can be displayed.

That is, as shown in (d) of FIG. 9E, negative wall charges continuously accumulate on the M electrode, and negative (−) wall charges and (+) walls alternately on the X electrode and the Y electrode in the sustain discharge section in the steady state. Charges accumulate.

As described above, according to the embodiment of the present invention, since the discharge is performed by the short gap discharge of the X electrode and the M electrode (or between the Y electrode and the M electrode) at the initial stage of the sustain discharge, sufficient discharge is performed even in a state where there are few priming particles, and In the state, since the discharge is performed by the long gap discharge between the X electrode and the Y electrode, stable discharge can be performed.

Further, according to the embodiment of the present invention, since the voltage waveforms which are substantially symmetrical are applied to the X electrode and the Y electrode, the circuits for driving the X electrode and the Y electrode can be designed almost identically. Therefore, since the difference in circuit impedance between the X electrode and the Y electrode can be almost eliminated, it is possible to reduce the distortion of the pulse waveform applied to the X electrode and the Y electrode in the sustain discharge section, thereby achieving stable discharge.

According to the first embodiment of the present invention shown in FIG. 8, the waveforms of the X electrode and the Y electrode can be driven even if they are reversed, and the driving can be performed even if the waveforms of the X electrode and the Y electrode are changed in the address period.

According to the driving method according to the first embodiment of the present invention described above, a reset waveform and a scan pulse waveform are mainly applied to the M electrode, and a sustain voltage waveform is mainly applied to the X electrode and the Y electrode. In this case, the reset waveform applied to the M electrode may be applied to various types of reset waveforms as well as the reset waveform shown in FIG. 8.

In this case, when applying the reset waveform of various forms to the four-electrode structure according to the embodiment of the present invention, it is preferable to satisfy the following conditions.

First, the voltage waveform Rm (v) applied to the M electrode in the rising reset waveform section is larger than the voltage waveform Rx (v) applied to the X electrode or the voltage waveform Ry (v) applied to the Y electrode. Should be set. (Rm (v)〉 (Rx (v) or Ry (v))

Second, in the falling reset waveform section, the voltage waveform Fm (v) applied to the M electrode is greater than the voltage waveform Fx (v) applied to the X electrode or the voltage waveform Fy (v) applied to the Y electrode. It should be set small. (Fm (v) 〈(Fx (v) or Fy (v))

Third, in the address period, the voltage waveform Am (v) applied to the M electrode is set smaller than the voltage waveform Ax (v) applied to the X electrode or the voltage waveform Ay (v) applied to the Y electrode. Should be. (Am (v) 〈(Ax (v) or Ay (v))

Fourth, at the time of the sustain discharge period, the voltage waveform Sm (v) applied to the M electrode is greater than the voltage waveform Sx (v) applied to the X electrode or the voltage waveform Sy (v) applied to the Y electrode. It should be set large. (Sm (v) < (Sx (v) or Sy (v)) Further, the voltage waveform Sm (v) applied to the M electrode at the time of the sustain discharge period is applied to the M electrode at the address period Am. (v)) (Sm (v)> Am (v))

10 is a diagram illustrating a plasma display device according to an exemplary embodiment of the present invention.

As shown in FIG. 10, a plasma display device according to an exemplary embodiment of the present invention includes a plasma display panel 100, an address driver 200, a Y electrode driver 300, an X electrode driver 400, and an M electrode driver ( 500 and the control unit 600.

The plasma display panel 100 includes a plurality of address electrodes A1 to Am arranged in the column direction, a plurality of Y electrodes Y1 to Yn arranged in the row direction, X electrodes X1 to Xn, and M _ij. An electrode. In this case, the M _ij electrode refers to an electrode formed between the Y _i electrode and the X _j electrode.

The address driver 200 receives an address driving control signal S _A from the controller 600 and applies a display data signal for selecting a discharge cell to be displayed to each address electrode.

The Y electrode driver 300 receives the Y electrode driving signal S _Y from the controller 600 and applies the waveform shown in FIG. 8 to the Y electrode.

The X electrode driver 400 receives the electrode driving signal S _X from the controller and applies the waveform shown in FIG. 8 to the X electrode.

The M electrode driver 500 receives the M electrode driving signal S _M from the controller 600 and applies the corresponding waveform shown in FIG. 8 to the M electrode.

The controller 600 receives an image signal from the outside and generates an address driving control signal S _A , a Y electrode driving signal S _Y , an X electrode driving signal S _X , and an M electrode driving signal S _M. do.

FIG. 11 is a view illustrating in more detail the driving waveform of the sustain discharge section in the driving waveform shown in FIG. 8.

As previously described with reference to FIG. 9E, the bias voltage Vm applied to the M electrode directly contributes to the initiation of discharge only in the first sustain pulse, and from the second sustain pulse due to the bias voltage applied to the M electrode. Discharge should be minimized.

However, after the discharge is completed, the applied voltages of the X electrode and the Y electrode are both 0V or an unwanted discharge between the M electrode and the X electrode or between the M electrode and the Y electrode in the rising (or falling) portion of the application pulse of the X electrode or the Y electrode. This can happen. This discharge is caused by the positive bias voltage applied to the M electrode and the negative wall charges accumulated on the X electrode (or Y electrode), which discharges the wall charges accumulated on the X electrode (or Y electrode) and then retains it. It may adversely affect the discharge.

12 is a view showing a driving waveform according to a second embodiment of the present invention.

As shown in FIG. 12, according to the second exemplary embodiment of the present invention, the M electrode is biased to a constant voltage in the first sustain discharge pulse section, and the M electrode is floated from the second sustain discharge pulse section.

Fig. 13 shows an equivalent circuit in the case where the M electrode is floated.

In Fig. 13, C1 denotes a capacitor between the X and M electrodes, and C2 denotes a capacitor between the Y and M electrodes. Assuming that the voltage applied to the X electrode is Vx and the voltages applied to the Y electrode are Vy and C1 = C2, the voltage Vmf of the M electrode when the M electrode is floated is expressed by the following equation.

From the above equation, it can be seen that when the M electrode is floated, the voltage of the M electrode becomes the average voltage of the voltage applied to the X electrode and the voltage applied to the Y electrode. Therefore, according to the second exemplary embodiment of the present invention shown in FIG. 12, the M electrode is floated from the second sustain discharge pulse to lower the voltage applied to the M electrode than the bias voltage, thereby being applied to the X electrode or the Y electrode. Discharge with the M electrode can be prevented from occurring even in a portion where the sustain discharge pulse falls (or rises).

According to the second embodiment of the present invention shown in FIG. 12, the floating of the M electrodes from the second sustain discharge pulse has been described as an example, but from the second and subsequent sustain discharge pulses (eg, the third sustain discharge pulse) to M. FIG. It is also possible to float the electrodes.

14A is a diagram illustrating a driving waveform according to a third embodiment of the present invention.

As shown in FIG. 14A, according to the third exemplary embodiment of the present invention, in the first sustain discharge pulse period, the M electrode is biased to the sustain discharge voltage (Vm), and between the M electrode and the X electrode or between the M electrode and the Y electrode. Perform a short gap discharge. From the second sustain discharge pulse, the voltage Vm ', which is lower than the sustain discharge voltage Vm, is applied to the M electrode. Here, the voltage of Vm 'applied from the second sustain discharge pulse to the M electrode is preferably applied such that the sustain discharge is not applied between the X electrode or the Y electrode.

As described above, according to the third embodiment of the present invention, since the voltage Vm 'applied from the second sustain discharge pulse to the M electrode is lower than the sustain discharge voltage Vm, from the second sustain discharge pulse, the X electrode or The discharge with the M electrode can be prevented from occurring even in a portion where the sustain discharge pulse applied to the Y electrode falls (or rises) or in a portion where the X electrode and the Y electrode are grounded.

According to the third exemplary embodiment of the present invention illustrated in FIG. 14A, the voltage Vm ′ is applied to the M electrode from the second sustain discharge pulse as an example. However, as shown in FIG. 14B, the third sustain discharge pulse starts from the third sustain discharge pulse. The voltage Vm 'may be applied to the M electrode, and the voltage Vm' may be applied to the M electrode from a subsequent sustain discharge pulse.

Next, a driving waveform according to a fourth embodiment of the present invention will be described.

A typical plasma display device uses an automatic power control (APC) method for calculating a screen load ratio according to an average signal level of image data and automatically controlling power consumption according to the load ratio. This method classifies the screen load ratio into 256 steps, for example, sets the number of sustain discharge pulses for each step, and reduces the number of sustain discharge pulses on the high load screen and increases the number of sustain discharge pulses on the low load screen to reduce power consumption. .

In the high efficiency plasma display device such as the four-electrode structure as in the embodiment of the present invention, since the usable discharge pulse on the high-load screen can be reduced by about 1/4 compared to the conventional three-electrode plasma display device, the high-load screen The problem of gray scale expression in can occur.

The driving waveform according to the fourth embodiment of the present invention has been made in view of such a point, and the waveforms shown in Figs. 11 and 12 are selectively applied according to the load ratio. That is, when the load factor is high, the M electrode is floated as shown in FIG. 12, and when the load factor is low, the bias voltage Vm is supplied to the M electrode as shown in FIG.

Specifically, according to the fourth embodiment of the present invention, when the load factor of the screen is high, as shown in FIG. 12, even when the X electrode or the Y electrode rises (or falls) with the M electrode, as shown in FIG. By preventing the discharge from occurring, the luminance per unit pulse is reduced. As described above, according to the fourth embodiment of the present invention, when the load ratio is high, the luminance per unit pulse (that is, the unit luminance of the gradation expression) can be reduced, so that accurate gradation expression is possible even under high load conditions.

When the load ratio is low, since the sustain discharge pulse is sufficient, a bias voltage is applied to the M electrode so that sufficient brightness can be expressed.

Next, a plasma display device for supplying a driving waveform according to a fourth embodiment of the present invention will be described.

The basic configuration of the plasma display device for supplying the driving waveform according to the fourth embodiment of the present invention is almost the same as that of the plasma display device described above with reference to FIG. 10, and the configuration of the controller 600 will be described below. This is different.

FIG. 15 is a diagram illustrating in detail the configuration of a controller for supplying a driving waveform according to a fourth exemplary embodiment of the present invention.

Referring to FIG. 15, the controller 600 includes an image signal level calculator 620, a high load rate determination unit 640, and a floating switch controller 660.

The image signal level calculator 620 calculates an average signal level of the input image data (R, G, B signals). At this time, the calculation of the video signal level is easily understood by those skilled in the art to which the present invention belongs, so a detailed description thereof will be omitted.

The high load rate determination unit 640 determines whether the input video signal is a high load video signal or a low load video signal based on the average signal level of the video data calculated by the video signal level calculator 620. do. In this case, a detailed determination on whether the high load rate is performed is performed by comparing the input video signal level with the reference signal level (the reference signal level can be arbitrarily set).

The floating switch controller 660 controls a control signal to turn off a floating switch (not shown) electrically connected between the M electrode and the bias voltage when the input image signal is a high load according to the determination result of the high load rate determination unit 640. Is output to the M electrode driver, and when the video signal has a low load rate, a control signal for turning on the floating switch is output to the M electrode driver.

Next, a driving method according to the fifth and sixth embodiments of the present invention will be described with reference to FIGS. 16 and 17.

Referring to FIG. 16, while the X electrode is biased to the ground voltage, the ground voltage and the Vs voltage are alternately applied to the M electrode. The -Vs voltage is applied to the Y electrode while the ground voltage is applied to the M electrode, and the Vs voltage is applied to the Y electrode while the Vs voltage is applied to the M electrode.

When the waveform shown in Fig. 16 is applied to the X electrode, the Y electrode and the M electrode, the voltage between the X electrode and the Y electrode, the voltage between the X electrode and the M electrode, and the voltage between the Y electrode and the M electrode are shown in Fig. 8. It can be seen that the same as the waveform shown. That is, even when the waveform shown in FIG. 16 is applied, the sustain discharge process is performed in the same manner as the waveform shown in FIG.

On the other hand, when the waveform shown in Fig. 16 is applied, the Y electrode needs to be biased to the ground voltage, so there is an advantage that a separate circuit for driving the Y electrode is not required.

Referring to Fig. 17, the waveforms of the Y electrode and the X electrode are the same as the waveforms shown in Fig. 16, except that the M electrodes are floated only in the sustain discharge period.

When the M electrode is floated, the M electrode has a waveform as shown in FIG. 17 because the average voltage values of the X electrode and the Y electrode are maintained.

Even when the waveform shown in FIG. 17 is applied to the X electrode, the Y electrode, and the M electrode, the voltage between the X electrode and the Y electrode, the voltage between the X electrode and the M electrode, and the voltage between the Y electrode and the M electrode are shown in FIG. 8. It can be seen that it is almost similar to the waveform shown in FIG.

Therefore, when the waveform shown in Fig. 17 is applied, not only a separate circuit for driving the Y electrode is required, but also the M electrode simply needs to be floated in the sustain discharge period, thereby simplifying the circuit of the M electrode driver. There is an advantage that it can.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various other modifications and changes are possible.

As described above, according to the present invention, since the reset or the first sustain discharge is performed by using the intermediate electrode, discharge failure can be prevented.

Claims (4)

A driving method of a plasma display device comprising a first electrode and a second electrode to which a sustain discharge voltage pulse is applied, and a third electrode formed between the first electrode and the second electrode, respectively. determining whether the load ratio of the input image signal is a high load rate or a low load rate; (b) when the determined load ratio is a high load ratio, floating the third electrode and applying a sustain discharge voltage pulse to the first electrode and the second electrode alternately during a first period; And (c) when the determined load ratio is a low load ratio, biasing the third electrode to a first voltage and applying sustain discharge voltage pulses alternately to the first electrode and the second electrode during the first period. Method of driving a plasma display device comprising. The method of claim 1, In steps (b) and (c) Biasing the third electrode to the first voltage and applying a sustain discharge voltage pulse to the first electrode or the second electrode during a second period, which is a period before the first period. Driving method. The method of claim 2, And the second section includes a section in which a first sustain discharge occurs. The method according to any one of claims 1 to 3, Step (a) is Calculating an average signal level of the input video signal; And comparing the calculated average signal level with a reference signal level to determine whether an input image signal is a high load rate or a low load rate.

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