KR100292465B1 - Plasma display panel using high frequency and its driving method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel using high frequency and a method of driving the same, which can ensure uniformity of discharge when high frequency discharge is used.

In the method of driving a plasma display panel using a high frequency of the present invention, an address period for sequentially generating lighting discharges according to image data in units of a low line, and a sustain pulse supplied with a high frequency pulse and at least two voltage levels when a lighting discharge occurs It characterized in that it comprises a high frequency discharge period so that the high frequency discharge is generated at the same time and maintained continuously.

According to the present invention, the next high frequency discharge is generated uniformly as a whole by uniformly activating charged particles uniformly distributed by the time required for data addressing by applying a large voltage at the beginning of the high frequency discharge.

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 plasma display panel and a driving method thereof capable of ensuring uniformity of discharge when high frequency discharge is used.

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 / sustain electrode (hereinafter referred to as a scan electrode) and a 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 vacuum ultraviolet rays generated by the continuous sustain discharge between the sustain electrodes 16 cause the phosphor 24 to be discharged. By exciting and 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.

In order to solve the low discharge efficiency problem of the PDP, a high frequency discharge using a high frequency voltage has recently emerged. The high frequency discharge is usually generated continuously by high frequency pulses in the range of several MHz to several hundred MHz, so that electrons vibrate between two electrodes to continuously ionize and excite the discharge gas in the discharge space. As a result, continuous discharge occurs without dissipation of electrons for most of the discharge time, thereby increasing the amount of vacuum ultraviolet rays, thereby increasing the luminance and the discharge efficiency. This high frequency discharge has a physical effect such as a positive column appearing in a discharge tube having a long distance between electrodes in a glow discharge.

In addition, the relationship between the distance (r) and the frequency (f) between the electrodes in the high frequency discharge 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. As described above, the PDP can increase the luminance and the discharge efficiency by using the high frequency discharge.

However, the conventional PDP driving method allows high frequency discharge to occur simultaneously on the entire screen after addressing the image data while scanning the entire screen. In this case, there is a problem that uneven discharge occurs during the next high frequency discharge due to the uneven distribution of the charged particles remaining in the discharge space of the charged particles of the discharge cell by the time of scanning the screen.

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

Another object of the present invention is to provide a PDP and a driving method thereof capable of stabilizing discharge cells in which high frequency discharge occurs in a short time.

1 is a cross-sectional view showing a discharge cell structure of a conventional AC plasma display panel.

2 is a cross-sectional view illustrating a discharge cell structure of a plasma display panel according to an exemplary embodiment of the present invention.

3 is a voltage waveform diagram for driving the discharge cell shown in FIG. 2 according to the plasma display panel driving method of the present invention.

4 is an electrode arrangement of the plasma display panel according to an embodiment of the present invention.

FIG. 5 is a voltage waveform diagram illustrating a method of driving the PDP shown in FIG. 4 according to the plasma display panel driving method of the present invention. FIG.

6 is a voltage waveform diagram for driving the discharge cell shown in FIG. 2 according to a plasma display panel driving method according to another embodiment of the present invention.

7 is a voltage waveform diagram for driving the plasma display panel shown in FIG. 4 according to a plasma display panel driving method according to another embodiment of the present invention;

8 is a view for explaining a gray scale implementation method of a plasma display panel driving method according to 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 scanning electrode 36 insulating layer

40: sustain electrode 44: discharge cell

21, 41: discharge space

In order to achieve the above object, a PDP using a high frequency according to the present invention is formed on a first substrate and a sustain electrode to which a high frequency pulse is applied, a scan electrode formed in parallel with the sustain electrode on the second substrate, and a second substrate. And a discharge space into which an address electrode formed to intersect with the scan electrode and discharge gases for causing gas discharge are injected.

The PDP driving method using the high frequency according to the present invention includes an address period in which writing discharge according to the image data is sequentially generated in units of a low line, and a sustain pulse supplied with a high frequency pulse and at least two levels of voltage values when a lighting discharge occurs. It characterized in that it comprises a high frequency discharge period so that the high frequency discharge is generated at the same time and maintained continuously.

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

2 is a cross-sectional view illustrating a discharge cell structure of a PDP according to an exemplary embodiment of the present invention, in which the discharge cell 44 of the PDP shown in FIG. 2 is formed of an address electrode 32 and a scan electrode formed on an upper substrate 26. 34, a sustain electrode 40 formed on the lower substrate 28, and a discharge space 41 provided between the upper substrate 26 and the lower substrate 28.

In the discharge cell 44 of the PDP shown in FIG. 2, the upper substrate 26 and the lower substrate 28 are arranged in parallel with each other. The address electrode 32 is formed in the vertical direction on the upper substrate 26. The insulating layer 36 is formed on the upper substrate 26 on which the address electrode 32 is formed, and the scan electrode 34 is formed in the direction perpendicular to the address electrode 32 on the insulating layer 36. A dielectric layer 38 for charge accumulation is formed on the insulating layer 36 on which the scan electrode 34 is formed. The sustain electrode 40 to which a high frequency voltage is supplied is formed on the lower substrate 28 in a direction parallel to the scan electrode 34. On the lower substrate 28 on which the sustain electrode 40 is formed, a phosphor 42 for generating visible light having a unique color (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, a protective layer is not required on the surface of the dielectric layer 38 because there is little ion impact on the electrode during high frequency discharge, but a protective layer may be formed to increase the efficiency of secondary electron generation.

3 illustrates a voltage waveform for driving the discharge cell shown in FIG. 2 according to the PDP driving method of the present invention.

In FIG. 3, section a is a section in which the discharge cell 44 is turned off while no voltage is applied to the electrodes 32, 34, and 40. Subsequently, as the data pulse is supplied to the address electrode 32 and the synchronization pulse is supplied to the scan electrode 34 in the b section, which is a writing period, a voltage difference greater than the discharge start voltage occurs between the two electrodes 32 and 34. As the discharge starts, charged particles are generated. At this time, the generated charged particles are kept small in the discharge space 41 without disappearing until the completion of the addressing of the other discharge cells, that is, during the b period. Then, in the c section, as the sustain period, high frequency pulses are supplied to the sustain electrode 40 and two steps of sustain pulses are supplied to the scan electrode 34 so that high frequency discharge occurs continuously. At this time, the sustain period is time-divided into sections c1 and c2 to supply a relatively large voltage to the scan electrode 34 in the section c1 to activate the minute charged particles uniformly with other discharge cells. In the c2 section, by supplying a relatively low voltage to the scan electrode 34 to maintain a high frequency discharge together with the high frequency pulse supplied to the sustain electrode 40, only the ions cannot move and only the electrons are scanned and the sustain electrode ( There is a vibration movement between 40). As a result, the high-frequency discharge causes the electrons to vibrate in the discharge space and ionize and excite the discharge gas continuously, and emits vacuum ultraviolet light while emitting excited atoms and molecules to the ground state, thereby emitting phosphors. Therefore, when the supply period of the high frequency pulse supplied to the sustain electrode 40 together with the width of the sustain pulse supplied to the scan electrode 34 is adjusted, the light emission time can be controlled, so that the brightness can be adjusted. In addition, when the voltage of the sustain pulse supplied to the scan electrode 34 during the period c2 of the sustain period is equal to the center voltage Vc of the high frequency pulse applied to the sustain electrode 40, the peak-to-peak voltage of the high frequency pulse. If it is about 30-50V, the high frequency discharge mentioned above is attained. Next, the period d is an erasing period, whereby the supply of the high frequency pulse to the sustain electrode 40 stops the vibrating motion and the electrons are attracted to the scan electrode 34 to dissipate the charged particles, thereby stopping the light and the light. This will not come out.

4 is an electrode arrangement diagram of a PDP according to an exemplary embodiment of the present invention, in which the PDP shown in FIG. 4 includes address electrode lines X1, X2, X3,..., And scan electrode lines Y1, Y2 arranged on an upper substrate. , Y3,..., Sustain electrodes 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 scan electrode lines Y1, Y2, Y3,... Z) is arranged to correspond to each row line. A discharge cell 44 is provided at each cross point of the address electrode lines X1, X2, X3, ..., the scan electrode lines Y1, Y2, Y3, ..., and the sustain electrode lines Z. Here, the address electrode lines X1, X2, X3, ... and the scan electrode lines Y1, Y2, Y3, ... are driven separately, while the Z sustain electrode lines Z are commonly connected and simultaneously. Will be driven.

Referring to FIG. 5, a voltage waveform for driving the PDP shown in FIG. 4 according to the PDP driving method of the present invention is shown. In FIG. 5, the PDP driving method generates a high frequency discharge at the same time after addressing the entire discharge cells 44 in units of scan lines (ie, row lines).

In detail, data pulses corresponding to 1 bit of each pixel data are applied to the address electrode lines X1, X2, X3,. In addition, scan pulses synchronized with data pulses applied to the address electrode lines X1, X2, X3,... Are sequentially supplied to the scan electrode lines Y1, Y2, Y3,. Accordingly, the discharge cells 44 of the PDP are sequentially addressed along the row line. The charged particles generated in this addressing period remain small without being destroyed until the completion of the entire addressing. Then, the cells selected in the addressing period are driven by a high frequency pulse which is commonly supplied to the sustain electrode lines Z and two step sustain pulses which are simultaneously supplied to the scan electrode lines Y1, Y2, Y3, ... It will cause a high frequency discharge. At this time, a high voltage sustain pulse is applied to the scan electrode lines Y1, Y2, Y3,... In the first half of the sustain period, and the discharge cells 44 addressed together with the high frequency pulse applied to the sustain electrode lines Z. The internally charged particles are activated uniformly, and then the voltage value of the sustain pulse is lowered to maintain the high frequency discharge by the width of the sustain pulse. Subsequently, at this point in time, the supply of the high frequency pulses supplied to the sustain electrode lines Z is stopped to stop the high frequency discharge.

6 illustrates voltage waveforms for explaining a PDP driving method according to a second embodiment of the present invention.

In the PDP driving method of FIG. 6, the high frequency pulse is supplied to the sustain electrode 40 only in the sustain period c in the PDP driving method of FIG. 5, while the high frequency pulse is supplied throughout the entire period. In this case, high frequency pulses are supplied to the sustain electrode 40 in section a, but no charge particles are generated in the discharge cells 44 so that discharge does not occur. The operation in the writing section b and the sustain period c is as described above. In the erase period d, the electrons are attracted to the scan electrode 34 to be extinguished by applying a voltage outside the high frequency voltage range to the scan electrode 34 to prevent the electrons from vibrating by the high frequency pulse. Therefore, the light emission time is adjusted by varying the width of the sustain pulse.

7 illustrates a voltage waveform for driving the PDP shown in FIG. 4 according to the second embodiment of the PDP driving method.

In FIG. 7, high frequency pulses are commonly applied to the sustain electrode lines Z throughout the entire period. The data supplied to the address electrodes X1, X2, X3, ... is addressed by the scanning pulses sequentially supplied to the scan electrode lines Y1, Y2, Y3, ..., and the scan electrode lines Y1, Y2. , Y3, ...) causes high frequency discharge continuously by two-step sustain pulses applied simultaneously. In addition, a voltage outside the high frequency voltage range is applied to the scan electrode lines Y1, Y2, Y3, ... to stop the high frequency discharge.

Referring to FIG. 8, a method of expressing a gray level of one frame image by a PDP driving method according to an exemplary embodiment of the present invention is illustrated.

In general, the PDP time-divisions one frame into sub-fields (SF) equal to the number of bits of the image data to express the gray level of the image, and adjusts the sustain period differently for each subfield, which is proportional to the sustain period. A gray level of one frame is implemented by determining a gray level value and combining the gray level 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 an addressing period in which binary data is sequentially addressed in units of low lines, and at the same time, a sustain period in which high frequency discharge is generated to continuously maintain the discharge. In addition, an erase period for canceling the high frequency discharge may be further included.

As described above, according to the PDP using the high frequency and the driving method thereof according to the present invention, by uniformly activating the charged particles uniformly distributed by the time required for data addressing by applying a large voltage at the beginning of the high frequency discharge The next high frequency discharge is generated uniformly as a whole.

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 (9)

In the discharge cells arranged in a matrix form on the plasma display panel, A sustain electrode formed on the first substrate and to which a high frequency pulse is applied; A scan electrode formed in parallel with the sustain electrode on a second substrate; An address electrode formed on the second substrate to intersect the scan electrode; And a discharge space into which discharge gases are injected to cause gas discharge. A driving method of a plasma display panel having discharge cells provided at intersections of a scan electrode and a sustain electrode disposed to face each other and having an address electrode, An address period in which writing discharges according to the image data are sequentially generated in units of row lines, A method of driving a plasma display panel using a high frequency wave, wherein the writing discharge includes a high frequency discharge period in which a high frequency pulse is generated by a high frequency pulse and a sustain pulse supplied at a voltage value of at least two stages at the same time. . The method of claim 2, And an erasing period for stopping the high frequency discharge. The method of claim 3, wherein And applying a voltage other than the high frequency voltage range to the scan electrode to stop the high frequency discharge. The method of claim 2, The high frequency discharge period Applying a high voltage sustain pulse to the scan electrode at the beginning of the high frequency discharger to activate the charged particles generated by the writing discharge together with the high frequency pulse supplied to the sustain electrode; And maintaining a high frequency discharge by the high frequency pulse by applying a sustain pulse of a relatively low voltage value to the scan electrode. The method of claim 2, And a high frequency pulse is applied to the sustain electrode only during the high frequency discharge period. The method according to claim 2 or 6, And controlling the period during which the high frequency pulse is supplied and the length of the sustain pulse to adjust the high frequency discharge period. The method of claim 2, And the high frequency pulse is commonly supplied to the sustain electrode over the entire period. The method according to claim 2 or 8, And controlling the high frequency discharge period by varying a length of the sustain pulse.