KR100285762B1 - Plasma display panel using high frequency and its driving method - Google Patents

Abstract

The present invention relates to a PDP and a driving method thereof capable of increasing the discharge efficiency by using a high frequency discharge.

The PDP using the high frequency of the present invention includes a first sustain electrode to which a high frequency pulse is applied, a second sustain electrode arranged side by side to face the first sustain electrode, an address electrode disposed to intersect the second sustain electrode, and a gas. And a discharge space into which discharge gases for causing discharge are injected.

According to the present invention, the PDP vibrates electrons in the discharge space by using a high frequency pulse of several MHz or more, thereby enabling continuous discharge without dissipation of electrons for most of the discharge time, thereby greatly increasing discharge efficiency, brightness, and luminance efficiency. It becomes possible.

Description

Plasma Display Panel Using High Frequency and its Driving Method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device, and more particularly, to a PDP and a driving method thereof capable of increasing discharge efficiency using high frequency discharge.

Recently, researches on plasma display panels (hereinafter referred to as PDPs), which are easy to manufacture panels as large-area flat panel displays, have been actively conducted according to the needs of large flat panel displays. The PDP generally uses a gas discharge phenomenon to display characters or graphics using visible light generated by vacuum ultraviolet rays generated during gas discharge by exciting the phosphor.

Referring to FIG. 1, a structure of a discharge cell configured in a PDP of a three-electrode alternating current (AC) surface discharge method which is commonly used is shown.

The discharge cell of the PDP shown in FIG. 1 includes an upper substrate 10 which is a display surface of an image, and a lower substrate 12 arranged in parallel with the upper substrate 10 by the partition 14. The partition wall 14 serves to support the upper plate 10 and the lower plate 12 as well as providing a discharge space 21 inside the cell to block electrical and optical interference between the cells. On the upper substrate 10, a pair of sustain electrodes 16, that is, a scan and sustain electrode (hereinafter referred to as Y sustain electrode) and a sustain electrode (hereinafter referred to as Z sustain electrode) are arranged side by side. The sustain electrode pair 16 and the address electrode 22 for discharging are disposed on the lower substrate 12. On the upper substrate 10 on which the sustain electrode pairs 16 are arranged, a dielectric layer 18 for charge accumulation is formed flat, and a protective film 20 is formed on the surface of the dielectric layer 18. The protective film 20 not only protects the dielectric layer 18 from the sputtering of plasma particles, thereby prolonging its lifetime, but also enhances the emission efficiency of secondary electrons and reduces the change in discharge characteristics of the refractory metal due to oxide contamination. Magnesium oxide (MgO) membranes are mainly used. On the lower substrate 12 on which the address electrode 22 is disposed, a phosphor layer 24 for generating visible light having a unique color is coated. The phosphor layer 24 is excited by vacuum ultraviolet rays (VUV) of short wavelengths generated during gas discharge to generate visible light of red, green, and blue (R, G, B). In addition, the discharge gas 21 is filled in the discharge space 21 provided in the discharge cell.

The discharge cell having such a configuration is selected by the address discharge between the address electrode 22 and the sustain electrode 16 and then the vacuum ultraviolet rays generated by the continuous sustain discharge between the sustain electrodes 16 excite the phosphor 24. By emitting visible light, the PDP can display a desired image. At this time, by adjusting the number of sustain discharges to implement the step-by-step brightness, that is, gray scale (Gray Scale) required for the image display. Accordingly, the number of sustain discharges has become an important factor in determining the luminance and discharge efficiency of the PDP. For this sustain discharge, a step pulse having a duty ratio of 1 is periodically applied to the sustain electrodes 16 at a frequency of about 200 to 300 kHz and a pulse width of about 10 to 20 kHz. In this case, the sustain discharge occurs only once at an extremely short instant per sustain pulse. The charged particles generated by the sustain discharge move the discharge path formed between the two sustain electrodes according to the polarity of the electrode, so that wall charges are formed inside the discharge space of the cell and the discharge voltage in the discharge space decreases due to the wall charges. The discharge stops. As described above, the sustain discharge by the conventional sustain pulse is generated only once at a short time per pulse, and most of the other time is consumed in the preparation of the wall charge and the next discharge, so that the discharge efficiency of the PDP is inevitably low. Accordingly, the low discharge efficiency of the PDP has emerged as a problem to be solved.

Accordingly, it is an object of the present invention to provide a PDP and a driving method thereof capable of increasing discharge efficiency by using high frequency discharge.

1 is a cross-sectional view showing the structure of a conventional AC PDP cell.

2 is a cross-sectional view showing the structure of a PDP cell according to an embodiment of the present invention.

3 is a voltage waveform diagram illustrating a PDP driving method according to an embodiment of the present invention.

4 is an electrode arrangement diagram of a PDP according to an embodiment of the present invention.

5 is a voltage waveform diagram for explaining a method of driving the PDP shown in FIG.

6 is a view for explaining a gray scale implementation method of the PDP driving method according to the present invention.

7 is a voltage waveform diagram illustrating a PDP driving method according to another embodiment of the present invention.

<Brief description of symbols for the main parts of the drawings>

10, 26: upper substrate 12, 28: lower substrate

14, 30: partition 16: sustain electrode

18, 38: dielectric layer 20: protective layer

22, 32: address electrodes 24, 42: phosphor

34: Y sustain electrode 36: insulating layer

40: Z sustain electrode 44: discharge cell

21, 41: discharge space

In order to achieve the above object, the PDP according to the present invention is disposed so as to intersect a first sustain electrode to which a high frequency pulse is applied, a second sustain electrode arranged to be parallel to the first sustain electrode, and a second sustain electrode. And an discharge space into which the address electrode and discharge gases for generating gas discharge are injected.

In addition, the PDP according to the present invention includes: address electrode lines arranged to correspond to each column line, first sustain electrode lines arranged to correspond to each roo line, to which a high frequency pulse is applied, and first sustain electrode lines; And opposite discharge cells arranged at opposite points of the address electrode line and the first and second sustain electrode lines.

In addition, the PDP driving method according to the present invention includes the steps of sequentially generating writing discharges based on data pulses in units of a low line, and sequentially generating high frequency discharges in high order by a high frequency pulse when a writing discharge occurs. It is characterized by including.

Other objects and advantages of the present invention in addition to the above object will become apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

The PDP according to the present invention uses a high frequency discharge due to a high frequency waveform of a few MHz to several hundred MHz as a display discharge.

In other words, the conventional PDP terminates the discharge by generating one discharge per sustain pulse and moving charged particles along the discharge path between the two sustain electrodes to form wall charge in the dielectric layer. High frequency discharge is generated by the high frequency signal, and electrons vibrate between the two electrodes to continuously ionize and excite the discharge gas in the discharge space. As a result, continuous discharge occurs during almost the discharge time, thereby increasing the amount of vacuum ultraviolet rays, thereby increasing the luminance and the discharge efficiency. At this time, the discharge efficiency of the PDP by high frequency discharge has a physical effect such as positive column appearing in the discharge tube with a long distance between the electrodes.

In such a high frequency discharge, the relationship between the distance r between the electrodes and the frequency f has an inverse relationship as shown in the following equation.

Where r is the distance between the electrodes, m is the mass of the electron, ω is the frequency (ω = 2πf), and v _m is the number of collisions. This indicates that the desired high frequency discharge can be obtained by adjusting the frequency f of the high frequency waveform according to the distance r between the electrodes. In other words, when the distance r between electrodes is far, the frequency is lowered, whereas when the distance r between electrodes is close, the frequency is increased to obtain a desired high frequency discharge. Here, in order to facilitate the control necessary for image display, it is more preferable that the distance r between the electrodes is far rather than close so that a high frequency of relatively low frequency can be used.

2, there is shown an embodiment of a discharge cell structure of a PDP suitable for high frequency discharge. The discharge cells of the PDP shown in FIG. 2 include an address electrode 32 and a Y sustain electrode 34 formed on the upper substrate 26, a Z sustain electrode 40 formed on the lower substrate 28, and an upper substrate. The discharge space 41 provided between the 26 and the lower substrate 28 is provided.

In the discharge cell of the PDP shown in FIG. 2, the upper substrate 26 and the lower substrate 28 are disposed to face each other in parallel. On the upper substrate 26, an address electrode 32 to which data pulses are supplied is formed in the vertical direction. The insulating layer 36 is formed on the upper substrate 26 on which the address electrode 32 is formed, and the Y sustain electrode 34 for maintaining the discharge is perpendicular to the address electrode 32 on the insulating layer 36. Is formed in the direction. The dielectric layer 38 for charge accumulation is formed on the insulating layer 36 on which the Y sustain electrode 34 is formed. On the lower substrate 28, a Z sustain electrode 40 to which a high frequency voltage is supplied is formed in a direction parallel to the Y sustain electrode 34. On the lower substrate 28 on which the Z sustain electrode 40 is formed, a phosphor 42 for generating visible light of intrinsic colors (red, green, blue) is coated. Between the upper substrate 26 and the lower substrate 28, partition walls 30 are formed in a direction parallel to the address electrode 32 to provide a discharge space 41 in which optical interference with adjacent cells is excluded. .

In addition, due to the principle of high frequency discharge, positive ions remain almost stationary because their mass is relatively heavier than electrons, and thus they cannot move instantaneously due to changes in the high frequency field. Accordingly, since there is little ion impact on the electrode during high frequency discharge, a protective layer is not required on the upper plate, but a protective layer may be formed on the dielectric layer 38 to increase the efficiency of secondary electron generation.

Here, any one of the upper substrate and the lower substrate may be used as the display surface of the image. In this case, the electrodes disposed on the substrate used as the display surface of the image are formed as transparent electrodes that can transmit light.

As a driving method of a discharge cell having such a configuration, an address discharge is generated between the address electrode 32 and the Y sustain electrode 34, and then a high frequency voltage between the Y sustain electrode 34 and the Z sustain electrode 40 is generated. The continuous high frequency discharge causes continuous ionization and excitation of the discharge gas in the discharge space 41 while the electrons vibrate between the two sustain electrodes 43 and 40 to generate continuous discharge for almost most of the discharge time. It becomes possible.

Specifically, as shown in FIG. 3A, in the section a in which the high frequency waveform is applied only to the Z sustain electrode 40, no charge particles are generated inside the discharge cell, and thus, no discharge occurs and light is emitted. It does not emit light. Subsequently, when data pulses and sustain pulses are supplied to each of the address electrode 32 and the Y sustain electrode 34 as shown in (B) and (C), the writing period during which the data pulses are supplied, that is, the address in the b period. As the voltage difference between the electrode 32 and the Y sustain electrode 34 is equal to or higher than the discharge start voltage, the discharge is started, thereby generating charged particles. The charged particles generated at this time are ions do not move due to the high frequency voltage applied to the Z sustain electrode 40 in the sustain period in which the sustain pulse is supplied to the Y sustain electrode 34, that is, the c section, and only the electrons are Y and Z. Vibration movement is performed between the sustain electrodes 34 and 40. At this time, electrons are not attracted to the Y and Z sustain electrodes 34 and 40. In this manner, the high-frequency discharge causes electrons to vibrate in the discharge space and ionize and excite the discharge gas continuously, and emits vacuum ultraviolet rays while emitting excited atoms and molecules to the ground state, thereby emitting phosphors. Therefore, when the sustain pulse width supplied to the Y sustain electrode 34 is changed, the time for which light is emitted can be adjusted, so that the brightness can be adjusted. In addition, when the voltage of the sustain pulse supplied to the Y sustain electrode 34 coincides with the center voltage Vc of the high frequency pulse applied to the Z sustain electrode 40 during this sustain period, the peak-to-peak voltage of the high frequency pulse is If it is about 30-50V, the high frequency discharge mentioned above is attained. As such, by using a relatively low high frequency voltage, selective writing and erasing are possible. Then, the period d is an erasing period, and when a voltage outside the high frequency voltage range applied to the Z sustain electrode 40 is applied to the Y sustain electrode 34, electrons are attracted to the Y sustain electrode Y while the vibration width decreases, so that the charged particles Dissipation stops the discharge and prevents light from coming out.

4 illustrates an electrode arrangement diagram of a PDP according to an exemplary embodiment of the present invention, in which the PDP illustrated in FIG. 3 includes address electrode lines X1, X2, X3, ... and Y sustain electrode lines disposed on an upper substrate. (Y1 Y2, Y3, ...), Z sustain electrode lines Z disposed on the lower substrate, and discharge cells 44 arranged in a matrix form.

In the PDP of FIG. 4, the address electrode lines X1, X2, X3,... Are arranged to correspond to each column line, and the Y sustain electrode lines Y1 Y2, Y3,... (Z) is arranged to correspond to each row line. The discharge cells 44 corresponding to the pixels at the intersections of the address electrode lines X1, X2, X3,..., The Y sustain electrode lines Y1, Y2, Y3,..., And the Z sustain electrode lines Z. Will be provided. Here, the address electrode lines X1, X2, X3, ... are used for data input, and the Y sustain electrode lines Y1 Y2, Y3, ... and the Z sustain electrode lines Z scan the screen and maintain a discharge. It is used to Here, the address electrode lines X1, X2, X3, ... and the Y sustain electrode lines Y1 Y2, Y3, ... are driven separately, while the Z sustain electrode lines Z are commonly connected and driven simultaneously. Will be.

Referring to FIG. 5, a voltage waveform diagram for sequentially driving a row line in the PDP shown in FIG. 4 is shown.

First, a high frequency waveform is commonly applied to the Z sustain electrode lines Z as shown in FIG. 5A, and at one time, one bit is included in the address electrode lines X1, X2, X3, .... Corresponding data pulses are applied in horizontal periods, that is, in rowline units. The sustain pulses synchronized with the data pulses applied to the address electrodes X1, X2, X3, ... are sequentially supplied to the Y sustain electrode lines Y1 Y2, Y3, .... Accordingly, the discharge cells 44 of the PDP shown in FIG. 4 are sequentially addressed while following the low line, and the selected cells are then supplied with widths of the sustain pulses supplied to the Y sustain electrodes Y1 Y2, Y3,... As long as the light emission is maintained.

Referring to FIG. 6, a method of expressing a gray level of an image for one frame by the PDP driving method according to an exemplary embodiment of the present invention is illustrated.

In general, the PDP time-divisions one frame into the same number of sub-fields (SF) as the number of bits in order to express the gray level of the image, and adjusts the sustain period differently for each subfield, thereby adjusting the gray scale value in proportion to the sustain period. The gradation of a frame is implemented by determining the s and combining the gradation values. Similarly, in the PDP driving method of the present invention, as shown in FIG. 6, one frame includes eight subfields SF1, SF2, ..., SF8 corresponding to 8-bit data, and Y sustain electrode lines for each subfield. The gray level is realized by varying the width of the sustain pulse applied to (Y). At this time, each subfield is composed of a writing period in which writing discharge is selectively performed by binary data, a sustain period in which discharge is maintained by high frequency discharge, and an erasing period in which discharge is erased. In addition, the writing discharge sustain discharge and the erase discharge of each subfield are generated in a row-line unit in chronological order.

FIG. 7 illustrates a voltage waveform for explaining a PDP driving method according to another embodiment of the present invention. The data pulse supplied to the address electrode 32 and the sustain applied to the Y sustain electrode 34 shown in FIG. The voltage of the sustain pulse applied to the Y sustain electrode Y is made larger only in the b section where the lighting discharge occurs due to the difference in the voltage of the pulse, thereby causing a sure lighting discharge.

As described above, according to the PDP using the high frequency according to the present invention and the driving method thereof, the PDP uses electrons in the discharge space by using high frequency pulses of several tens of MHz or more as compared with the conventional method using pulses of several hundred kHz during display discharge. By vibrating at, continuous discharge is possible. Accordingly, the PDP using the high frequency according to the present invention can substantially increase the discharge efficiency, the brightness and the brightness efficiency by continuously discharging without dissipation of the electrons for most of the discharge time. In addition, the PDP according to the present invention increases energy efficiency compared to the same brightness, thereby reducing power consumption. In addition, selective writing and erasing are possible by not performing high frequency high voltage writing and discharging.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (12)

In the plasma display panel having cells arranged in a matrix form, each of the cells A high frequency electrode for applying a high frequency voltage, An address electrode for applying a data voltage, A scan electrode for supplying the scan voltage for the data voltage and the address discharge and used for high frequency discharge by the high frequency voltage; And a discharge space into which discharge gases are injected to cause gas discharge. The method of claim 1, A first substrate on which the address electrode and the scan electrode are disposed; A second substrate on which the high frequency electrode is disposed; An insulating layer formed between the address electrode and the scan electrode; A dielectric layer formed on the insulating layer on which the scan electrode is disposed; A phosphor layer coated on the second substrate on which the high frequency electrode is disposed; And a partition wall formed between the first and second substrates to provide the discharge space. The method of claim 2, And a protective film formed on the dielectric layer. The method of claim 2, Any one of the first and second substrates is used as the image display surface, And an electrode arranged on the side of the image display surface is a transparent electrode. The method of claim 1, The scan electrode applies a sustain voltage during a period during which the address discharge and the high frequency discharge occur so as to continuously generate the address discharge and the high frequency discharge, and applies a voltage outside the high frequency voltage range to stop the high frequency discharge. Plasma display panel using a high frequency, characterized in that. The method of claim 5, And said sustain voltage is constant as a center voltage of said high frequency voltage. The method of claim 5, And the scan electrode supplies the sustain voltage at which the voltage value supplied in the address discharge period is greater than the voltage value supplied in the next high frequency discharge period. A method of driving a plasma display panel in which cells having a high frequency electrode, an address electrode, and a scan electrode are arranged in a mates shape, The high frequency electrode continuously applies a high frequency voltage, the address electrode applies a data voltage pulse, and the scan electrode sequentially applies a sustain voltage pulse along the row line formed of the cells, thereby making a noisy value of the data voltage pulse. To cause the address discharge according to the line sequential, and to cause the high frequency discharge to be generated in the line sequential by the vibrating motion of the charged particles generated by the address discharge by the high frequency voltage during the sustain voltage pulse is applied Plasma display panel driving method using a high frequency, characterized in that it comprises a step of. The method of claim 8, And the scan electrode sequentially applying a voltage outside the high frequency voltage range along the row line to stop the high frequency discharge in a line order. The method of claim 8, And controlling the high frequency discharge period by varying the length of the sustain voltage pulse. The method of claim 8, And the voltage of the sustain voltage pulse is constant at the center voltage of the high frequency voltage. The method of claim 8, And a voltage supplied in said sustain voltage pulse to said address discharge period is greater than a voltage supplied to a center voltage of said high frequency voltage in a subsequent high frequency discharge period.