KR20010004123A - Method for driving plasma display panel - Google Patents

Abstract

PURPOSE: A method for driving a plasma display panel is provided which increases the magnitude of discharge sustain voltage of a discharge sustain voltage pulse in a sustain discharge period of a sub-field for realization of multi-level images, to drive the plasma display panel with high brightness and high efficiency. CONSTITUTION: In a method for driving a plasma display panel that selectively combines X sub-fields to which sustain discharge period is allocated in the ratio of 2<SP POS="POST">0</SP>:2<SP POS="POST">1</SP>:2<SP POS="POST">2</SP>:...2<SP POS="POST">x-1</SP>, respectively, to compose one-frame picture, a discharge sustain pulse of discharge sustain voltage is applied to a scan electrode and a sustain electrode alternately during the sustain discharge period of the first sub-field among the X sub-fields, and the discharge sustain pulse with voltage higher than the discharge sustain voltage is applied to the scan electrode and the sustain electrode alternately during the sustain discharge period of the sub-fields other than the first sub-field.

Description

Driving Method of Plasma Display Panel {METHOD FOR DRIVING PLASMA DISPLAY PANEL}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of driving a plasma display device. In particular, the present invention relates to a display of a plurality of subfield screens according to a gradation to implement one frame screen of a plasma display panel (hereinafter referred to as PDP). It relates to a driving method of the PDP.

Recently, with the development and spread of information processing systems, the importance of displays has increased, and research and development of various flat displays having a matrix structure have been actively performed. Among them, PDP is being spotlighted as the next generation of large screen displays. The PDP has a large screen and a small thickness, and has been applied to wall-mounted TVs, home theater displays, and various monitors.

In addition, the PDP is classified into an alternating current (AC) type and a direct current (DC) type according to the type of driving voltage. The AC type PDP is driven by a sine wave AC voltage or a pulse voltage, and the DC type PDP is It is driven by DC voltage.

1 is an electrode arrangement diagram of a three-electrode surface discharge PDP, which is one of the most commonly used AC PDPs.

As shown in FIG. 1, a typical three-electrode surface discharge PDP has a scan electrode (3, Y electrode) to which a scan pulse is applied during an address period, and a sustain electrode to which a sustain pulse is applied to maintain a discharge. (4, X electrode) and an address electrode (2) to which data pulses are applied in order to cause sustain discharge between the scan electrode (3) and the sustain electrode (4) of the selection line. The cell 5 is formed at the point where the scan electrode 3 and the sustain electrode 4 intersect the address electrode 2 as the horizontal electrode, and these cells are gathered to form a plasma display panel.

The basic driving principle of each cell of the three-electrode surface discharge PDP configured as described above is to generate an address discharge between the scan electrode 3 and the address electrode 2 so that wall charges are generated therein, and then maintain the scan electrode 3 and the sustain electrode. Sustain discharge is caused between the electrodes 4 to make the discharge gas into a plasma state to generate ultraviolet rays, and the ultraviolet rays excite the phosphor to generate visible light.

Meanwhile, the address display-period separation (ADS) subfield method, which is the most basic method for driving the three-electrode surface discharge PDP, will be described.

The ADP driving method of the PDP includes an initialization step of uniformly erasing all wall charges of the entire cell when the PDP is driven, a write discharge step (addressing) and a display for forming wall charges in cells at specific positions. The driving method is divided into three stages of the sustain discharge stage, that is, a write discharge is selectively performed on the discharge cells to be displayed. First, in the initialization step, a high voltage higher than the discharge start voltage V _f is applied between the scan electrodes Y ₁ to Y _m and the sustain electrodes X ₁ to X _m so that all display lines are irrelevant regardless of the previous display state. All the discharge cells are front-charged and self-discharged to all discharge cells on all display lines using a long pulse but slightly lower than Vs (discharge sustain voltage), so that the charge distribution of all discharge cells in the panel has no wall charge. Reset to a uniform state. In the write discharge step, the sustain electrodes X ₁ to X _m maintain a constant potential, and perform selective write discharges between the scan electrodes Y ₁ to Y _m and the address electrodes A ₁ to A _n . Subsequently, when the selective write discharge is completed, discharge sustain voltage pulses having a constant Vs (discharge sustain voltage) level are common to each of the scan electrodes Y ₁ to Y _m and sustain electrodes X ₁ to X _m . The number of pulses applied at this time is differentiated for the gradation display which will be described later. After all three steps are completed, the process returns to the initialization step and is repeated.

One cycle is configured through three periods of the reset period for performing the initialization step, the address period for performing the write discharge step, and the sustain discharge period (or sustain period) for performing the sustain discharge step. For this purpose, one frame screen is divided into a plurality of subfield screens and displayed. Each of the subfield screens is composed of a reset period, an address period, and a sustain discharge period. Among them, the reset period and the address period are all identically assigned to each subfield, but the sustain discharge period is digital image data displayed in the address period. Since they are differently assigned according to the bit weights of, the combination of the respective subfields using the integration effect of the eyes enables multi-gradation of the image.

2 is an explanatory diagram showing a general ADS subfield driving method of a PDP.

The drawing shows a driving method in the case of displaying 256 gradations as an example of multi gradation display. In FIG. 2, one frame is divided into eight subfields SF1, SF2, SF3, SF4, SF5, SF6, SF7, SF8. In these subfields SF1 to SF8, the reset period and the address period are basically the same length, but the length of the sustain discharge period is 1 (2 ⁰ ): 2 (2 ¹ ): 4 (2 ² ): 8 (2 ³ ): 16 (2 ⁴ ): 32 (2 ⁵ ): 64 (2 ⁶ ): 128 (2 ⁷ ). Therefore, by appropriately selecting a subfield to be lit within one frame, it is possible to realize gray levels having different luminance in 256 steps from 0 to 255. For example, the sustain period of the first tone when is ^20, that is, the first sub-field (SF1) of sustain discharge using only the period, and 100 gray levels when the third, sixth, seventh subfields (SF3, SF6, SF7) of In the 256 gray scale implementation, the sustain discharge period of all eight subfields is used.

In this case, the general ADS subfield driving method is divided into eight by two times the on time of the sustain discharge period, and the number of pulses having the same pulse width and the same pulse height according to the on time. It is like arranging it by 2 times. That is, one discharge sustain voltage pulse number having a magnitude of Vs (discharge sustain voltage) commonly applied to the sustain electrodes (X electrodes) and the scan electrodes (Y electrodes) in the sustain discharge period of the first subfield SF1. In this case, two discharge sustain voltage pulses are doubled in the second subfield SF2 and four discharge sustain voltage pulses are tripled in the third subfield SF3.

However, in the ADS subfield type PDP driving method, the discharge sustain voltage pulses having the same pulse width and the same pulse height are alternately applied in the multi-gradation implementation, and are maintained by expressing the gray scale according to the number of pulses applied. The length of the discharge period is long, resulting in low brightness and efficiency and problems of pseudo contours.

The present invention has been made to solve the above problems, the same sustain discharge period by increasing the discharge sustain voltage of the discharge sustain voltage pulse in the sustain discharge period of the subfield to implement the multi-gradation when driving the PDP of the ADS subfield method An object of the present invention is to provide a method of driving a PDP that drives the PDP with high brightness and high efficiency.

In addition, the present invention is to increase the size of the discharge sustain voltage of the discharge sustain voltage pulse in the sustain discharge period of the subfield to reduce the length of the sustain discharge period when expressing the same gray scale in order to implement a multi-gradation when driving the PDP of the ADS subfield method It is intended to provide a driving method.

1 is a layout view of electrodes of a typical plasma display panel.

2 is an explanatory diagram showing a general ADS subfield driving method of a PDP.

3 is a view showing only the sustain discharge period of each subfield during ADS driving by comparing the conventional ADS subfield driving method with the ADS subfield driving method of the present invention.

According to the present invention for achieving the above object, the sustain discharge periods are respectively set to 2 ⁰ : 2 ¹ : 2 ² :... A method of driving a plasma display apparatus in which one frame screen is configured by selecting and combining X subfields SF1, SF2, ..., SFX allocated at a ratio of 2 ^x-1 for a predetermined time period, wherein the X subfields are configured. The discharge sustain pulse of the discharge sustain voltage is alternately applied to the scan electrode and the sustain electrode during the sustain discharge period of the first first subfield among the fields, and the discharge sustain voltage during the sustain discharge period of the remaining subfields except the first subfield. The discharge sustain pulse of the first voltage having a higher value is alternately applied to the scan electrode and the sustain electrode.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. do.

First, briefly summarizing the apparatus of the present invention, the PDP driving method of the present invention implements a multi-gradation by driving not only the number of discharge sustain voltage pulses, but also the height, that is, amplitude of the pulses during the sustain discharge period of the subfield. .

In reality, it is impossible to realize multi-gradation by only differentializing the amplitudes of the discharge sustain voltage pulses in the plurality of subfields due to the discharge characteristics of the PDP. However, in the case where the number of discharge sustain voltage pulses and the amplitude of the pulses are simultaneously differentiated as proposed by the present invention, multi-gradation of the image can be realized by the combination of each subfield.

First, as described above, the eight subfields SF1 to SF8 are divided by the sustain discharge time, that is, divided by the number of discharge sustain voltage pulses, but are divided by the gray level difference (luminance difference). In other words, the luminance increases by two times as the subfields increase.

The present invention combines the number of discharge sustain voltage pulses and the change in amplitude of each subfield to increase the luminance by 2 times as the subfields increase.

In addition, the present invention takes advantage of the fact that the characteristic relationship between the voltage and the current in the AC type PDP is nonlinear, but a linear section exists in a specific region of the discharge sustain voltage Vs. That is, when the discharge sustain voltage Vs rises by a predetermined amount α, the current increases linearly as well as the luminance increases linearly. This linear section is near the discharge sustain voltage of the ADS subfield driving method.

Therefore, even if the discharge sustain voltage Vs between the sustain dischargers is increased by only α, the luminance easily rises by " luminance ÷ 256 " when all 256 gradations are turned on. For example, if the luminance of one discharge sustain pulse having a discharge sustain voltage Vs of 180 V is 1 cd / m 2, the luminance becomes 256 cd / m 2 when the number of pulses is 256. Therefore, it is possible to give two pulses when a luminance of 2 cd / m 2 is desired. However, by increasing the discharge sustain voltage Vs by α, the luminance 2cd / m 2 can be realized with only one pulse. In this case, the α value depends on the panel characteristics of the PDP, and when the α value has a magnitude of 1 to 5 V, the luminance 2cd / m 2 is obtained using only one pulse of the discharge sustain voltage (Vs + α) increased by the α value. Can be implemented.

FIG. 3 is a view showing only the sustain discharge period of each subfield during ADS driving by comparing the conventional ADS subfield driving method with the ADS subfield driving method of the present invention.

In the figure, (a) shows a discharge sustain voltage pulse in the sustain discharge period for each subfield in the conventional ADS subfield driving method, and the first subfield SF1 includes one discharge sustain pulse of Vs size. The second subfield SF2 includes two discharge sustain pulses having a Vs magnitude, the third subfield SF3 has four discharge sustain pulses having a Vs magnitude, and the fourth subfield SF4 has a discharge sustain with a Vs magnitude. It includes eight pulses, and the fifth to eighth subfields also increase in the number of 16, 32, 64, and 128 pulses.

In the figure, (b) shows the discharge sustain voltage pulse in the sustain discharge period for each subfield in the ADS subfield drive method of the present invention, and the first subfield SF1 shows one discharge sustain pulse of Vs magnitude. The second subfield SF2 includes one discharge sustain pulse having a size of Vs + α, the third subfield SF3 has two discharge sustain pulses having a size of Vs + α, and the fourth subfield SF4 has a Four discharge sustaining pulses having a magnitude of Vs + α are included, and the fifth to eighth subfields also increase in the number of 8, 16, 32, and 64 pulses.

First, the conventional method of (a) is an ADS subfield driving method in which 256 gradations are realized with only the number of discharge sustain pulses during the sustain discharge period. As the number of subfields increases, the number of pulses increases by 2 times. In other words, the luminance is increased by 2 times. The discharge sustain pulse voltage at this time is Vs.

The driving method of the present invention of (B) has a discharge sustain pulse of one Vs magnitude in the first subfield SF1 as in the prior art. However, from the second subfield SF2, a voltage slightly higher than that of the conventional method Vs is applied to apply the discharge sustain voltage pulse of Vs + α. At this time, the α value varies depending on the panel, but in the case of the panel to which the same process is applied, the α value is almost the same and can be easily obtained after measuring the electro-optical characteristics of the panel. As described above, the luminance value when there are two Vs discharge sustain pulses is the same as when one pulse having a size of "Vs + α" is applied.

As shown in the figure, when the discharge sustain voltage pulse is applied in each subfield, each subfield can obtain the same brightness as before, and 256 gray levels can be realized by the combination.

Further, the driving scheme of the present invention reduces the sustain discharge period in the remaining subfields except the first subfield. That is, the number of sustain discharge periods can be reduced by reducing the number of pulses by adjusting the voltage magnitude of the discharge sustain pulses large. Therefore, the driving method of the present invention is capable of high brightness and high efficiency within a predetermined time compared to the conventional driving method and can reduce the possibility of pseudo contouring.

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

According to the present invention, the discharge sustain voltage of the discharge sustain voltage pulse in the sustain discharge period of the subfield is increased to achieve high brightness and high efficiency within the same sustain discharge period in order to realize the multi-gradation when driving the PDP of the ADS subfield method. There is an effect that can drive the PDP.

In addition, the present invention increases the magnitude of the discharge sustain voltage in the sustain discharge period of the subfield to reduce the number of discharge sustain voltage pulses in order to realize the multi-gradation when driving the PDP of the ADS subfield type, thereby reducing the length of the sustain discharge period when expressing the same gray scale. There is an effect to reduce.

Claims (3)

In order to display a multi-gradation image on the plasma display panel, the sustain discharge periods are respectively set to 2 ⁰ : 2 ¹ : 2 ² ... In the driving method of a plasma display apparatus for constructing a 1-frame screen by selecting and combining X subfields (SF1, SF2, ..., SFX) allocated at a ratio of 2 ^x-1 for a predetermined time in a cell unit, Discharge sustain pulses of the discharge sustain voltage are alternately applied to the scan electrode and the sustain electrode during the sustain discharge period of the first subfield of the X subfields; And the discharge sustain pulse of the first voltage having a value higher than the discharge sustain voltage is alternately applied to the scan electrode and the sustain electrode during the sustain discharge period of the remaining subfields except the first subfield. Method of driving. The method of claim 1, wherein the first subfield, And one discharge sustain pulse. The method of claim 1, wherein the remaining subfields except for the first subfield are sequentially. 2 ⁰ : 2 ¹ :... And 2 ^{x -2} discharge sustain pulses to reduce the sustain discharge period of each subfield when the same gray scale is expressed.