KR100268590B1 - A plasma display panel using high frequency and a operating method thereof - Google Patents

Abstract

The present invention relates to a PDP using a high frequency and a driving method thereof that can reduce power consumption when using a high frequency discharge.

A plasma display panel using a high frequency according to the present invention is a high frequency electrode to which a high frequency pulse is applied, an address electrode to which a video data pulse is applied, a high frequency electrode to generate a preliminary discharge, and a high frequency electrode to generate a secondary erase discharge. And a scan / erase electrode, a second scan / erase electrode for generating an address electrode, a preliminary discharge, a high frequency electrode and an address electrode, and a main erase discharge, and a discharge space filled with discharge gases.

According to the present invention, by using the space charge and the wall charge generated by the preliminary discharge during the next high frequency discharge, the voltage value of the high frequency pulse can be lowered, and the erase discharge can be divided into the secondary erase discharge and the main erase discharge. Since the voltage value can be lowered, power consumption can be reduced.

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 using a high frequency and a driving method thereof capable of reducing power consumption when using a high frequency discharge.

Recently, researches on plasma display panels (hereinafter referred to as PDPs), which are easy to manufacture large area flat panel display panels, have been actively conducted according to the needs of large flat panel display devices. 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.

The PDP normally uses glow discharge, but since the size of the discharge cell is too small, in practice, the positive-light area having high discharge efficiency is not used in the structure of the glow discharge tube. For this reason, in recent years, in order to increase brightness and efficiency within a limited space of the discharge cells, a method of forcibly utilizing the lifting area by changing the discharge area or extending the discharge path has been attempted. In addition, efforts have been made to improve the discharge efficiency by using another structure deviating from the structure of the discharge cell, for example, a structure of a large discharge cell and a large discharge space.

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

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 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. A dielectric layer 18 for charge accumulation is formed flat on the upper substrate 10 on which the sustain electrode pairs 16 are disposed, 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, the number of sustain discharges is adjusted to implement stepwise brightness, ie, gray scale, necessary for displaying an image. Accordingly, the number of sustain discharges is an important factor in determining the brightness 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 50 to 150 kHz and a pulse width of about 3 to 10 kHz. In this case, the sustain discharge occurs only once at an extremely short instant per sustain pulse. In addition, 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. Will stop. As described above, the sustain discharge by the existing 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. In general, high frequency discharge is continuously generated by high frequency voltage of several tens of MHz to hundreds of MHz, and electrons vibrate between two electrodes to continuously ionize and excite 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.

First, the relationship between the frequency and the sustain voltage will be described with reference to the high frequency discharge principle shown in FIG. 2.

Increasing the frequency of the voltage supplied between the two electrodes 2, 4 shown in FIG. 2 causes the movement of ions to be affected. This is because ions usually have a larger mass than electrons, so they cannot change direction quickly in response to an electric field. In this case, when the ion concentration is assumed to be μ _i , the distance x of the ion movement in the electric field (Ecoswt) formed by the voltage applied to the two electrodes 2 and 4 is the integral of the collision frequency v = μ _i Ecoswt x = μ _i E / w sinwt. Here, when the distance that the ions move, i.e., twice the amplitude 2x = 2μ _i E / w is smaller than the distance l between the two electrodes, as shown in FIG. 2, the ions starting from the center are the two electrodes (2, 4) It vibrates within an arbitrary interval in accordance with the high frequency voltage applied to the two electrodes 2, 4 and thus cannot reach. On the other hand, when the distance 2x in which ions move is larger than the distance l between both electrodes, even the ion in the center reaches either of the electrodes 2 and 4.

Here, if the frequency limit value for the distance l = 2μ _i E / w of both electrodes is set, and the frequency is increased beyond that condition, the number of ions trapped between the electrodes 2, 4 increases. As such, when the number of ions captured between the two electrodes 2 and 4 increases, the ions distort the electric field in the dark flow state. (Where α is the coefficient by which electrons move a unit distance and ionize through collision) is also larger at 1 atm than when the action of ions is less, and spark discharge is more likely to occur. In other words, it is possible to lower the discharge sustain voltage. As the frequency increases, the amplitude of the ions becomes smaller. In this case, since ions are difficult to move, the gamma (γ) action (where γ is the number of electrons protruding from one ion colliding with the cathode) is reduced, and the spark discharge voltage is slightly increased again. If the frequency is further increased, the electrons are captured between the electrodes 2 and 4 next to the mobile electrons. The condition for the electrons to be trapped by the positive electrodes 2 and 4 should be a distance l = 2 μ _e E / w between the positive electrodes 2 and 4, assuming that μ _e is the concentration of electrons. In this case, even if the electrons vibrate between the electrodes 2 and 4 and there is no gamma action, the generated electrons repeat the collision ionization with a long lifetime until the generated electrons disappear from the electrodes 2 and 4 by diffusion, so that the low sustain voltage The discharge starts even at. Here, the rock flow increases as long as the increase in electrons by ionization is larger than the diffusion loss. The critical condition is when the face is in equilibrium.

In the state where electrons are captured, ions do not move at all by the high frequency electric field, so there is no gamma action. Because regarded as more it is irrelevant to the electron mobility level μ _e frequency w to think that increasing the frequency when the vibration amplitude is reduced in inverse proportion to the frequency w, but actually move concentration μ _e itself also affected by the frequency w, under high-frequency electric field The vibration amplitude of the electron decreases significantly when the frequency w becomes equal to the collision frequency v. As the vibration amplitude of the electron decreases, the ionization action decreases, and the holding voltage increases when the frequency w becomes larger than the collision number v. The same phenomenon occurs for the amplitude of ions, but at atmospheric pressure, electrons have a much larger collision number v than ions, and especially electrons are trapped before the mobile concentration μ _i is affected by frequency w. . The equality of the frequency w and the collision v for the electron is one condition that can lower the holding voltage, which is the frequency of the microwave at atmospheric pressure.

On the other hand, in the glow discharge by the DC voltage, the cathode structure is important, and if there is no gap with the anode to some extent, the positive pole region does not appear. By the way, in the case of high frequency discharge, even if there is no gamma action at low pressure, the discharge can be started, and when the discharge is started, the electric field becomes small and there is a discharge type in which only a positive beam is present. Electrons are generated in the oscillating electric field, and diffusion becomes bipolar diffusion in the plasma, which is less than free diffusion of the electrons, so that generation and loss are balanced. In addition, a high frequency glow discharge generates a kind of seed near the electrode, and a higher voltage drop exists in the seed than in the positive column. Here, if the frequency is decreased or the current is increased, the seed near the electrode is destroyed to generate a gamma action, a negative glow immediately before both electrodes, and the sustain voltage drops. Here, the secondary glow disappears again when the current is reduced or the atmospheric pressure is lowered. Thus, the presence or absence of gamma action depends on the current as well as the frequency and pressure. The holding voltage is not changed much by the current, and if the current is reduced, there is no boglow.

As described above, in the high frequency discharge, the holding voltage can be lowered instead of increasing the frequency. However, this high frequency discharge also has a disadvantage of relatively high power consumption by using a high frequency pulse.

Accordingly, another object of the present invention is to provide a PDP using a high frequency discharge and a driving method thereof that can lower power consumption when using a high frequency discharge.

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

Figure 2 is a view for explaining the high frequency discharge principle applied to the present invention.

3 is a view showing the overall electrode arrangement of the plasma display panel according to an embodiment of the present invention.

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

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

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

10, 30: upper substrate 12, 32: lower substrate

14, 48: partition 16: sustain electrode pair

18, 36, 42: dielectric layer 20: protective layer

22, 44: address electrodes 24, 46: phosphor

34, 40: first and second scan / erase electrodes 38: high frequency electrodes

21, 41: discharge space

In order to achieve the above object, a PDP using a high frequency according to the present invention generates a high frequency electrode to which a high frequency pulse is applied, an address electrode to which a video data pulse is applied, a high frequency electrode and a preliminary discharge, and generates a high frequency electrode and an auxiliary erase discharge. A first scan / erase electrode for generating, a second scan / erase electrode for generating an address electrode and a preliminary discharge, and a high frequency electrode and an address electrode, and a main erase discharge, and a discharge space filled with discharge gases; It is characterized by.

In the PDP driving method according to the present invention, the pre-discharge between the first scan / erase electrode and the high frequency electrode and the pre-discharge between the second scan / erase electrode and the address electrode simultaneously occur in the entire discharge cell, and the high frequency pulse By the step of simultaneously starting and maintaining the high frequency discharge, and the auxiliary erase discharge occurs between the first scan / erase electrode and the high frequency electrode, and simultaneously the video data pulse between the high frequency electrode, the second scan / erase electrode and the address electrode. The selective primary erase discharge according to the characterized in that it comprises the step of sequentially occurring along the rouline.

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.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 3 to 5.

FIG. 3 illustrates an overall electrode arrangement of a PDP according to an embodiment of the present invention. The PDP shown in FIG. 3 includes first and second scan / erase electrode lines Y1, Y2, Y3,... , Yn) (Y1 ', Y2', Y3 ', ..., Yn'), and the high frequency electrode lines Z and the address electrode lines X1, X2, X3, ..., Xm arranged parallel to each other in the vertical direction. It is provided.

In the PDP of FIG. 3, the high frequency electrode lines Z and the address electrode lines X1, X2, X3,..., Xm are arranged to correspond to each column line, and the first and second scan / erase The electrode lines Y1, Y2, Y3, ..., Yn (Y1 ', Y2', Y3 ', ..., Yn') are arranged to correspond to each row line. High frequency electrode lines Z and address electrode lines X1, X2, X3, ..., Xm and first and second scan / erase electrode lines Y1, Y2, Y3, ..., Yn (Y1 ', Discharge cells are provided for each cross point of Y2 ', Y3', ..., Yn '), whereby n × m discharge cells are arranged in a matrix form. The partition wall 48 formed in parallel with the high frequency electrode lines Z and the address electrode lines X1, X2, X3,..., Xm serves to exclude optical interference between adjacent cells. Here, the high frequency electrode lines Z are used to maintain a high frequency discharge, and the address electrode lines X1, X2, X3, ..., Xm are used to input data, and the first and second scan / erase electrode lines. (Y1, Y2, Y3, ..., Yn) (Y1 ', Y2', Y3 ', ..., Yn') are used to initiate discharge and selectively erase discharge in accordance with data while scanning the screen. At this time, the address electrode lines X1, X2, X3, ..., Xm and the first and second scan / erase electrode lines Y1, Y2, Y3, ..., Yn (Y1 ', Y2', Y3 ', ..., Yn ') are individually driven while the high frequency electrode lines Z are commonly connected and driven simultaneously.

4 illustrates a discharge cell structure of a PDP according to an exemplary embodiment of the present invention, in which the discharge cells of the PDP shown in FIG. 4 are disposed on the upper substrate 30 so as to be perpendicular to each other. ) And between the high frequency electrode 38, the second scan / erase electrode 40 and the address electrode 44 disposed perpendicular to each other on the lower substrate 32, and between the upper substrate 30 and the lower substrate 32. And a discharge space 41 provided by the partition wall 48.

In the discharge cell of the PDP shown in FIG. 4, the upper substrate 30 and the lower substrate 32 are disposed to face each other. The first scan / erase electrode 34 is disposed in the horizontal direction on the upper substrate 30. An upper dielectric layer 36 is formed on the upper substrate 30 on which the first scan / erase electrode 34 is disposed. The high frequency electrode 38 is disposed perpendicular to the first scan / erase electrode 34 on the upper dielectric layer 36. The second scan / erase electrode 40 is disposed in the horizontal direction on the lower substrate 32. The lower dielectric layer 42 is formed on the lower substrate 32 on which the second scan / erase electrode 40 is disposed. The address electrode 44 is disposed perpendicular to the second scan / erase electrode 40 on the lower dielectric layer 42. The phosphor 46 is coated on the lower substrate 32 on which the address electrode 44 is disposed to emit visible light having a unique color by vacuum ultraviolet rays generated during high frequency discharge. A partition wall 48 is formed between the upper substrate 30 and the lower substrate 32 to provide a discharge space 41 in which optical interference between adjacent discharge cells is eliminated, and the upper substrate 30 and the lower substrate 32 are separated from each other. Will play a supporting role. In addition, a protective layer (not shown) may be formed on the surface of the upper dielectric layer 36 to increase the efficiency of secondary electron generation during high frequency discharge.

In the discharge cell of this structure, a high frequency discharge, which is a kitchen discharge, is generated between the high frequency electrode 38 and the address electrode 44, and electrons are attracted to both electrodes 38 and 44 in the discharge space 41 by a high frequency discharge. Vibration movement is not performed. Accordingly, it is possible to maintain the discharge even at a low voltage without the energy lost by the electrons hitting the wall surface.

Here, since the distance between the high frequency electrode 38 and the address electrode 44 must be sufficiently secured for the high frequency discharge, the height of the discharge cell is set to 2 to 5 times higher than in the related art.

5 is a diagram illustrating a voltage waveform for explaining a PDP driving method according to an exemplary embodiment of the present invention, and FIG. 5 is a unit of a row line while initiating a high frequency discharge in all of the discharge cells and then maintaining a high frequency discharge. A method of sequentially erasing discharges of discharge cells having no display data is shown.

First, a negative voltage pulse is commonly supplied to the first scan / erase electrode lines Y1, Y2, Y3, ..., Yn, and a high frequency waveform is superimposed on the high frequency electrode lines Z. This causes discharge on the upper substrate side. At the same time, a negative voltage pulse is supplied to the second scan / erase electrode lines Y1 ', Y2', Y3 ', ..., Yn' and applied to the address electrode lines X1, X2, X3, ..., Xm. The positive voltage pulse is supplied to cause discharge on the lower substrate side. Accordingly, space charges are generated in the discharge space 41 of the discharge cell, and wall charges are formed in the upper and lower dielectric layers 36 and 42. Therefore, the next high frequency discharge uses the space charge and the wall charge generated by the above-described initial discharge, so that the high frequency discharge is easily generated even by the high frequency pulse of the low voltage value. At this time, the amount of space charge and wall charge is changed by the difference in voltage across the electrode. Subsequently, as the high frequency pulse is supplied to the high frequency electrode lines Z, high frequency discharge is started in all the discharge cells to be maintained continuously. Next, a data pulse is applied to the address electrode lines X1, X2, X3,..., Xm at a desired time point and is synchronized with the first scan / erase electrode lines Y1, Y2, Y3,. Erasing pulses are sequentially applied to the second scan / erase electrode lines Y1 ', Y2', Y3 ', ..., Yn' to selectively erase the discharge of the discharge cells having no display data. In detail, a positive erase pulse is applied to the first scan / erase electrode lines Y1, Y2, Y3,..., And Yn, and the second scan / erase electrode lines Y1 ', Y2', Y3 ',. Yn '), a negative erase pulse is applied, and a positive data pulse is applied to the address electrode lines X1, X2, X3, ..., Xm. In addition, a high frequency pulse is applied to the high frequency electrode lines Z. As a result, the electrons vibrated by the high frequency pulses are separated from the first scan / erase electrode line Y, the high frequency electrode line Z, and the second scan / erase electrode line Y 'and the address electrode line X. The voltage difference is attracted to the address electrode line X and eventually disappears. In detail, auxiliary erasing occurs due to a voltage difference between the first scan / erase electrode line Y and the high frequency electrode line Z, and the high frequency electrode line Z and the second scan / erase electrode line Y '. ) And the address gap occurs due to the voltage difference between the address electrode line X and the address electrode line X. FIG. In this manner, the erasing of the high frequency discharge is performed by dividing the auxiliary erasing and the addressing, thereby lowering the voltage value applied for the erasing discharge. In this case, the degree of erase of the electrons is largely influenced by the potential difference between the first scan / erase electrode line Y, the second scan / erase electrode line Y ', and the address electrode line X.

When a discharge is initially generated, a voltage is applied between the first scan / erase electrode line Y and the high frequency electrode Z, and a voltage between the second scan / erase electrode line Y 'and the address electrode X. When the high frequency pulse is supplied in the state where the square wave voltage is applied to the high frequency electrode Z, the high frequency discharge hardly occurs between the first scan / erase electrode Y and the high frequency electrode Z, and the voltage difference of the square wave is General discharge occurs. This is because the distance between the first scan / erase electrode Y and the high frequency electrode Z is not sufficiently secured. In other words, high frequency discharge can occur only when the distance between two electrodes is secured to some extent. In this case, since the high frequency pulse is loaded on the square wave, the peak value of the substantially applied voltage becomes high, so that the initial discharge occurs easily even at a low voltage. In addition, since the high frequency pulses required for the high frequency discharge have frequencies in the tens to hundreds of MHz bands, it is difficult to synchronize them. Therefore, the high frequency pulses supplied to the high frequency electrodes are continuously supplied regardless of synchronization.

As described above, according to the PDP using the high frequency and the driving method thereof, the voltage value of the high frequency pulse can be lowered by using the space charge and the wall charge generated by the preliminary discharge during the next high frequency discharge. In addition, according to the PDP using the high frequency and the driving method thereof according to the present invention, it is possible to reduce the voltage value of the erase pulse by dividing the erase discharge by the auxiliary erase. Accordingly, power consumption can be reduced by lowering the voltage value of the high frequency pulse and the voltage value of the erase pulse.

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 high frequency electrode to which a high frequency pulse is applied; An address electrode to which a video data pulse is applied, A first scan / erase electrode for generating the high frequency electrode and the preliminary discharge and generating the high frequency electrode and the auxiliary erase discharge; A second scan / erase electrode for generating a preliminary discharge with the address electrode and for generating an address discharging discharge with the high frequency electrode and the address electrode; A plasma display panel using a high frequency, characterized in that it comprises a discharge space filled with the discharge gas. The method of claim 1, A first substrate on which the first scan / erase electrode and the high frequency electrode cross each other; A second substrate on which the address electrode and the second scan / erase electrode cross each other; A partition wall formed between the first and second substrates to provide the discharge space; A first dielectric layer formed between the first scan / erase electrode and the high frequency electrode; A second dielectric layer formed between the address electrode and the second scan / erase electrode; And a phosphor for emitting visible light by ultraviolet rays generated during gas discharge. The method of claim 1, A plasma display panel using a high frequency, characterized by further comprising a protective film for increasing the generation efficiency of secondary electrons at the start of high frequency discharge. The method of claim 1, A preliminary discharge by a writing pulse applied to the first scan / erase electrode and a high frequency pulse superimposed on a square wave pulse to the high frequency electrode, and a writing pulse applied between the second scan / erase electrode and the address electrode Preliminary discharge occurs simultaneously, And a high frequency discharge using the wall charge and the space charge generated by the preliminary discharge by the high frequency pulse applied to the high frequency electrode. The method of claim 1, Auxiliary erase discharge is generated by the erase pulse applied to the first scan / erase electrode and the high frequency pulse, and selectively by the erase pulse applied to the high frequency pulse and video data pulse and the second scan / erase electrode. And the high frequency discharge is maintained by the high frequency pulse when the main erase discharge occurs and the high frequency discharge is not stopped. A method of driving a plasma display panel in which discharge cells including first and second scan / erase electrodes, high frequency electrodes, and address electrodes are arranged in a matrix form, Preliminary discharge between the first scan / erase electrode and the high frequency electrode and preliminary discharge between the second scan / erase electrode and the address electrode occur simultaneously in the entire discharge cell; The high frequency discharge is simultaneously started and maintained by the high frequency pulse; An auxiliary erase discharge occurs between the first scan / erase electrode and the high frequency electrode, and a selective main erase discharge according to the video data pulse is generated between the high frequency electrode, the second scan / erase electrode, and the address electrode. A plasma display panel driving method using a high frequency, characterized in that it comprises the step of generating sequentially. The method of claim 6, Preliminary discharge due to a high frequency pulse applied to the first scan / erase electrodes simultaneously and superimposed on a square wave pulse to the high frequency electrode, and between the second scan / erase electrodes and the address electrodes A method of driving a plasma display panel using high frequency, characterized in that a preliminary discharge is generated by a writing pulse applied to the same time. The method of claim 6, An erase pulse sequentially supplied to the first scan / erase electrodes and an auxiliary erase discharge by the high frequency pulse, and a video data pulse supplied to the high frequency pulse and the address electrode and the second scan / erase electrodes sequentially A method of driving a plasma display panel using a high frequency, characterized in that the main erase discharge due to the erase pulse is applied sequentially along the rouline. The method of claim 6, The remaining discharge cells except the discharge cells in which the erase discharge is generated, the high frequency discharge is maintained by the high frequency pulse, characterized in that the plasma display panel driving method using a high frequency.