KR100323976B1 - Driving Method of Plasma Display Panel Using High Frequency - Google Patents

Abstract

The present invention relates to a method of driving a plasma display panel using a high frequency that can reduce power consumption when using a high frequency discharge.

A method of driving a plasma display panel using a high frequency according to the present invention includes: applying a data pulse to an address electrode and applying a scan pulse to a scan electrode in synchronization with the data pulse to generate a preliminary discharge to select a cell to be displayed; Applying a predetermined high frequency pulse to the sustain electrode and applying a bias voltage to the sustain bias electrode to the sustain bias electrode to cause a high frequency discharge in a cell selected by the preliminary discharge; Canceling the high frequency discharge by stopping the high frequency pulse applied to the sustain electrode.

According to the present invention, the charged particles generated by the preliminary discharge are utilized at the time of high frequency discharge and the high frequency pulse is supplied only at the high frequency discharge, thereby reducing power consumption.

Description

Driving Method of Plasma Display Panel Using High Frequency

The present invention relates to a method of driving a plasma display panel, and more particularly, to a method of driving a plasma display panel using a high frequency that can reduce power consumption when using a 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 substrate 10 and the lower substrate 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 and a sustain electrode are arranged side by side. The sustain electrode pair 16 and the address electrode 22 for causing discharge 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 sputtering of plasma particles to extend its life, but also improves 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 a vacuum ultraviolet light (Vacuum Ultraviolet (VUV)) of short wavelengths generated during gas discharge to generate visible light of intrinsic colors (red, green, blue). Discharge gas 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 one sustain electrode pair 16, and then the vacuum ultraviolet light generated by the continuous sustain discharge between the sustain electrode pair 16 is discharged from the phosphor 24. Excitation) to emit visible light allows the PDP to display a desired image. At this time, by adjusting the number of sustain discharges to implement a step-by-step brightness, that is, gray scale (Gray Scale) necessary for displaying the image. 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 electrode pairs 16 periodically. At this time, the frequency is usually about 200 to 300 kHz and the pulse width is about 10 to 20 Hz. 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 has a disadvantage in that the power consumption ratio is high as the high frequency voltage value for the high frequency discharge is high.

Accordingly, an object of the present invention is to provide a method of driving a plasma display panel using high frequency which can greatly reduce power consumption by lowering the high frequency voltage value by using preliminary discharge.

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 for driving the PDP shown in FIG. 4 according to the plasma display panel driving method of the present invention. FIG.

6 is a view for explaining a gray scale implementation method in 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, 32: sustain electrode

18, 42: dielectric layer 20: protective layer

22, 40: address electrode 24, 42: phosphor

34: sustain bias electrode 36: resistive layer

38: scanning electrode 21: discharge space

41A: Auxiliary discharge space 41B: Kitchen discharge space

44: discharge cell

To achieve the above object; A method of driving a plasma display panel using a high frequency according to the present invention includes the steps of applying a data pulse to an address electrode and applying a scan pulse to a scan electrode in synchronization with the data pulse to cause a preliminary discharge to select a cell to display; Applying a predetermined high frequency pulse to the sustain electrode and applying a bias voltage to the sustain bias electrode to the sustain bias electrode to cause a high frequency discharge in a cell selected by the preliminary discharge; Canceling the high frequency discharge by stopping the high frequency pulse applied to the sustain electrode.

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.

2 illustrates a structure of a PDP discharge cell according to an embodiment of the present invention, in which the discharge cells of the PDP shown in FIG. 2 are disposed on the sustain electrode 32 and the lower substrate 28 formed on the upper substrate 26. The sustain bias electrode 34 and the scan electrode 38 formed, the address electrode 40 formed in the stepped portion of the partition wall 30, the auxiliary discharge space 41A provided by the partition wall 30, and the kitchen space ( 41B).

In the discharge cell of the PDP shown in FIG. 2, the upper substrate 26 and the lower substrate 28 are arranged in parallel with each other. On the upper substrate 26, which is the display surface of the image, a sustain electrode 32 to which a high frequency voltage is applied is formed in the form of a plate electrode or a net in the form of a transparent electrode ITO. On the lower substrate 28, a sustain bias electrode 34 to which a bias voltage for high frequency discharge is applied is formed in the same form as the sustain electrode 32. On the sustain bias electrode 34, a scan electrode 38 to which a scanning pulse is mainly applied is formed in parallel with the sustain bias electrode 34. As shown in FIG. The scan electrode 38 is provided with a protrusion 38A which protrudes through the resistive layer 36. In addition, an insulating layer (not shown) for electrically insulating is further formed between the sustain bias electrode 34 and the scan electrode 38. Between the upper substrate 26 and the lower substrate 28, a partition wall 30 is formed in the vertical direction to provide a discharge space 41 in which optical interference with adjacent cells is excluded. In particular, the partition wall 30 is formed in a structure of two or more stages to provide an auxiliary discharge space 41A for preliminary discharge and a kitchen discharge space 41B for high frequency discharge. In this case, the charged particles generated in the auxiliary discharge space 41A by the preliminary discharge can be moved to the kitchen space 41B during the high frequency discharge as it is to be used to reduce the voltage of the high frequency pulse. In addition, the light generated in the auxiliary discharge space 41A during the preliminary discharge is blocked by the stepped portion of the partition wall 30. An address electrode 40 to which a data signal is applied is formed in parallel with the partition wall 30 in the step portion located at the lower half side of the partition wall 30. On the upper half side of the partition wall 30, a phosphor 42 for emitting visible light having a unique color is applied by vacuum ultraviolet rays generated during high frequency discharge.

Referring to FIG. 3, a voltage waveform applied to each electrode of the discharge cell 44 shown in FIG. 2 according to the PDP driving method of the present invention is shown.

In FIG. 3, section a is a section in which the driving voltage is not applied to each electrode, and the section in which the discharge cell 44 is turned off. Subsequently, a period b in which a positive data pulse is supplied to the address electrode 40 and a negative scan pulse is supplied to the scan electrode 38 in synchronization with the address electrode 40 is a preliminary discharge period between the address electrode 40 and the scan electrode 38. A voltage difference greater than the discharge start voltage is generated to generate a preliminary discharge of the auxiliary discharge space 41A, thereby generating charged particles. The charged particles generated in the preliminary discharge stay in the auxiliary discharge space 41A without escaping into the discharge space 41B as the voltage of the scan electrode 38 is increased again. The charged particles are kept small without disappearing during the b period until the addressing of the other discharge cells is completed in the auxiliary discharge space 41A. These charged particles can be used to lower the high frequency pulse by using a high frequency discharge to be described later. Then, the voltage applied to the scan electrode 38 is lowered to move the charged particles staying in the auxiliary discharge space 41A toward the kitchen space 41B. At the same time, the high frequency discharge is continuously generated by the low frequency high frequency pulse supplied to the sustain electrode 32 and the bias voltage Vc applied to the sustain bias electrode 34. In other words, the charged particles moved to the kitchen space 41B by the negative voltage applied to the scan electrode 38 are continuously applied between the sustain electrode 32 and the sustain bias electrode 34 during the period c. Due to the excess frequency, the ions do not move and only the electrons are vibrated in a state in which they are not attracted to the electrodes between the two electrodes 32 and 34. Accordingly, the electrons vibrating in the discharge space 41 continuously ionize and excite the discharge gas, and emit the vacuum 42 by emitting vacuum ultraviolet rays while the excited atoms and molecules transition to the ground state. . In this case, when the length of the sustain pulse supplied to the scan electrode 38 is adjusted together with the supply period of the high frequency pulse supplied to the sustain electrode 32, the light emission time can be controlled, so that the brightness can be adjusted. The sustain bias electrode 34 is preferably supplied with the center voltage Vc of the high frequency pulse as the bias voltage. Then, by stopping the supply of the high frequency pulse to the sustain electrode 32 in the section d, the electrons are prevented from vibrating and attracted to the sustain bias electrode 34 to which the bias voltage Vc is supplied, thereby causing the charged particles to disappear. This stops the discharge and prevents light from coming out.

4 illustrates an electrode arrangement diagram of a PDP according to an embodiment of the present invention. The PDP illustrated in FIG. 4 includes sustain electrode lines Z disposed on an upper substrate, and sustain bias electrode lines disposed on a lower substrate. (SB) and scan electrode lines (Y1, Y2, Y3, ...), address electrode lines (X1, X2, X3, ...) arranged along the partition wall, and discharge cells formed at each intersection of the electrodes 44 is provided.

In the PDP of FIG. 4, the address electrode lines X1, X2, X3,... Are arranged to correspond to each column line, and the sustain bias electrode lines SB and the scan electrode lines Y1, Y2, Y3 are arranged to correspond to each column line. ,…) And the sustain electrode lines Z are arranged to correspond to each row line. Discharge is performed at each cross point of the address electrode lines X1, X2, X3, ..., the sustain bias electrode lines SB, the scan electrode lines Y1, Y2, Y3, ..., and the sustain electrode lines Z. By providing the cell 44, the discharge cells 44 are arranged in a matrix form. The address electrode lines (X1, X2, X3, ...) are used for image data input, the scan electrode lines (Y1, Y2, Y3, ...) scan a screen and maintain high frequency discharge, and sustain bias electrode lines SB and the sustain electrode lines Z are used to maintain high frequency discharge. At this time, the address electrode lines X1, X2, X3,... And the scan electrode lines Y1, Y2, Y3,... Are independently driven, while the sustain bias electrode lines SB and the sustain electrode lines ( Z) is commonly connected and driven simultaneously.

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 simultaneously generates high frequency discharge after addressing the entire discharge cells in units of scan 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 shown in FIG. 4 are addressed sequentially by performing a preliminary discharge along the row line. The charged particles generated in this addressing period do not disappear until the entire addressing is completed, and are kept in a small amount in the auxiliary discharge space 41A of the discharge cells 44. Subsequently, the charged particles formed in the auxiliary discharge space 41A of the discharge cells 44 selected in the addressing period are applied to the kitchen space by the sustain pulse which is commonly applied to the scan electrode lines Y1, Y2, Y3,. 41B). At the same time, high frequency discharge is continuously generated by the bias voltage Vc commonly supplied to the sustain bias electrode lines SB and the high frequency pulses commonly supplied to the sustain electrode lines Z. Will be maintained. Then, the high frequency discharge is stopped by stopping the supply of the high frequency pulse to the sustain electrode lines Z at the desired time point so that the charged particles disappear.

Referring to Fig. 6, there is shown a method of expressing the gradation of an image for one frame by the PDP driving method of the present invention.

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 is composed of eight subfields SF1, SF2, ..., SF8 corresponding to 8-bit data, and a sustain electrode line (for each subfield). The gray level is realized by varying the width of the sustain pulse applied to Z). At this time, each subfield is composed of an addressing period in which binary data is sequentially addressed in units of low lines, and a sustain period in which high frequency discharge is continuously maintained at the same time. The sustain period further includes an erase period for stopping the high frequency discharge.

As a result, the PDP driving method of the present invention can lower the voltage of the high frequency pulse by using the high frequency discharge of the charged particles generated by the preliminary discharge.

As described above, according to the driving method of the plasma display panel using high frequency according to the present invention, the charged particles generated by the preliminary discharge are utilized during high frequency discharge and the high frequency pulse is supplied only during the high frequency discharge, thereby reducing power consumption. You can do it.

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 (7)

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 sustain bias electrode formed on the second substrate in parallel with the sustain electrode and to which a bias voltage for high frequency discharge is applied; A partition wall formed between the first and second substrates to provide an auxiliary discharge space for preliminary discharge and a kitchen discharge space for the high frequency discharge; A scan electrode disposed on the second substrate in parallel with the sustain bias electrode; An address electrode disposed to intersect the sustain electrode at a stepped portion of the partition wall; And a phosphor layer applied to a portion of the partition wall that provides the electrical discharge space. An auxiliary discharge space and a discharge space are provided, and discharge cells including a sustain electrode to which a high frequency voltage is applied, a sustain bias electrode to which a bias voltage is applied to bias the high frequency voltage, a scan electrode, and an address electrode are arranged in a matrix form. In the method for driving a plasma display panel, Applying a data pulse to the address electrode and applying a scan pulse to the scan electrode in synchronization with the data pulse to cause a preliminary discharge to select a cell to be displayed; Applying a predetermined high frequency pulse to the sustain electrode and applying a bias voltage to the sustain bias electrode to the sustain bias electrode to cause a high frequency discharge in a cell selected by the preliminary discharge; And stopping the high frequency discharge by stopping the high frequency pulse applied to the sustain electrode. The method of claim 2, And the preliminary discharge is generated in the auxiliary discharge space. The method of claim 2, And a brightness of the high frequency discharge is controlled by the width of the sustain pulse applied to the scan electrode during the high frequency discharge. The method of claim 4, wherein And controlling the brightness of the high frequency discharge by varying the length of the sustain pulse together with the supply period of the high frequency pulse. The method of claim 2, The bias voltage is a plasma display panel driving method using a high frequency, characterized in that constant with the center voltage of the high frequency pulse. The method of claim 2, And stopping the supply of the high frequency pulse to the sustain electrode, thereby simultaneously erasing the high frequency discharge.