KR100221309B1 - Apparatus for controlling the sequence of power-off in a plasma display panel television and its method - Google Patents

Abstract

The present invention relates to an afterimage removing device and method thereof for powering off a PDP television, comprising a first to seventh switching unit, a power off signal generating unit, and a power off sequence control unit, wherein an address voltage is generated when the power is turned off. Turn off the power supply of the address voltage generator so as not to scan, and then turn off the power supply of the sustain voltage generator and the scan and sustain voltage generator so that no scan is performed and the sustain voltage is not generated. Turn off the power and turn off the power supply of the storage unit so that the image data is not stored. Then, turn off the power supply of the A / D conversion unit so that A / D conversion is not performed, and then stop the video signal receiving unit. By turning off the applied power, afterimages are not left on the PDP screen when the power is turned off.

Description

Apparatus and method for eliminating afterimages when PDP television is powered off

1 is a state diagram showing the generation of wall charges and the resulting discharge phenomenon when AC power is applied to one cell of the panel.

Figure 2a is a graph of the relationship between Vs and Vw and the resulting light output for a cell in the "on" state.

FIG. 2b is a graph of the relationship between Vs and Vw and resulting light output in a cell in the " off " state.

FIG. 3A is a waveform diagram of a write pulse Vw that causes a " off " cell to " on ".

3b is a waveform diagram of an erase pulse Ve that causes an " on " cell to " off "

4 is a state diagram and waveform diagram showing how addressing a 4 * 4 array.

5 is a block diagram of a PDP television to which an embodiment of the present invention is applied.

6 is a flowchart illustrating a method for removing afterimages when the PDP television is powered off according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

10: image signal receiving unit 12: first switching unit

14: A / D converter 16: second switching unit

18: storage unit 20: third switching unit

22: synchronization signal separation unit 24: buffer unit

26: fourth switching unit 28: address voltage generator

30: fifth switching unit 32: sustain voltage generating unit

34: sixth switching unit 36: scan and sustain voltage generator

38: seventh switching unit 40: plasma display panel

42: power off signal generator 44: power off sequence control unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel television, and more particularly, to an afterimage removing device and a method of powering off a plasma display panel television such that afterimages remain on the screen when the power is turned off.

Plasma Display Panel (hereinafter referred to as PDP) is a flat panel display device using Penning gas for discharge phenomenon. Neon or Helium gas of relatively high air pressure (over 100 Torr) is used. It refers to a display device using a light emitting phenomenon caused by the discharge between the narrow electrodes coated with a base-based gas as a dielectric material, inherently has a performance suitable for educational systems and the like in a computer terminal, and has been put to practical use as a computer display.

The penning gas is mainly Ne + Xe, Ne + He + Xe, and the reason for using such a mixed gas is that the discharge start voltage can be lowered when the mixed gas is more than one gas component. The discharge start voltage depends on the type of gas, the fanning gas pressure and the structure and shape of the panel (PASCHEN'S LAW).

PDPs are suitable for large-area display devices and can be colorized, so access to flat wall-mounted televisions has been made.

CRT (Cathode Ray Tude), which still holds a strong position in the display field, has some major drawbacks. That is, since the CRT itself has a fresco type structure, the size is large, the operating voltage is high, and a voltage of about 10,000 V is required, and a display distortion occurs.

In order to solve the drawbacks of the CRT, flat panel display devices having a matrix structure have been studied.

By adopting the matrix structure, the display distortion is solved, the planar structure is adopted to solve the problem of large size, and the problem of high voltage is solved by not using the high voltage driving electron beam.

Planar display devices include an electroluminescent display device (EL), a light emitting diode display device (LED), and a plasma display panel (PDP), which are active elements, and a liquid crystal display device (LCD) and an electrochromic display, which are passive elements. Device ECD and the like.

Among them, AC type PDPs are attracting attention as an active memory display panel capable of high-resolution large display.

Looking at the types of PDP can be classified as follows.

First, the PDPs are classified into AC type PDP (indirect discharge type) and DC type PDP (direct discharge type) according to the type of driving voltage applied to the discharge cell.

That is, the AC type PDP is driven by a sine wave AC voltage or a pulse voltage, while the DC type PDP is driven by a DC voltage.

In general, the two PDPs have a different structure. In the AC type PDP, the electrode is covered by the dielectric of the glass, whereas in the DC type PDP, the electrode is exposed as it is and a discharge current flows while the discharge voltage is applied.

The AC type PDP has a memory function inside the cell, but the DC type PDP has its advantages, such as gray scale, which facilitates image display.

Secondly, there are two types of memory, in which the panel itself stores display information, and a refresh type in which the panel itself has a memory of display information outside the panel and read it out and repeatedly displays it on the panel.

Third, according to the shape of the display, the panel has a lattice-shaped electrode, and the intersection of each electrode constitutes a pixel, and the degree of freedom is relatively high by the relationship of the points, and the degree of freedom is higher than that of the dot matrix type that displays characters and figures. There is a segment type used for small display.

Fourth, according to the type of the addressing mechanism of the discharge spot for display, the self-scan PDP and the self-shift, which is a functionalized panel display that provides the self-scanning function of the discharge point to the matrix type that independently addresses the cells at any place, There is a PDP.

PDP has the following advantages over other display devices.

Since PDP does not discharge below a certain voltage (Firing voltage), such a nonlinearity eliminates the limitation on the number of plasma display lines, which enables large-scale production and multiplexing technology for reducing the number of driving circuits.

The large matrix display has a memory function, which is necessary to eliminate high brightness and flicker, while the CRT has a lifespan of 20,000 hours, while the PDP has a lifespan of 50,000 hours.

PDP is suitable for mass production because there is no easily broken parts except glass, and its simple structure makes it possible to manufacture large panels and has a resolution of 100 Line / inch or more due to strong nonlinearity.

Since the discharging material is a gas, the refractive index value is 1, which means that the light is not extinguished by the internal reflection and the external light is not reflected or scattered by the display material.

In addition, unlike other flat panels, the PDP is sealed with glass above 400 ° C, which means that the plasma display can operate even under high humidity conditions or the presence of reactive gases. The change is only caused by the circuit.

Referring to FIG. 1, the driving principle of the PDP, such as the generation of wall charges and the resulting discharge phenomenon when AC power is applied to a cell of the panel, will be described with reference to the AC type PDP.

When a firing voltage (Vf: firing voltage) is applied at t0, the gas is ionized, electrons and ions are attracted to the anode and cathode, respectively, and the attracted ions and electrons generate wall charge as shown in FIG.

The voltage at t1 is smaller than the discharge start voltage (Vf) and a voltage having a changed polarity is applied. The reduced applied voltage is called a sustain voltage (VS), and the sustain voltage (Vs) is neon-argon-based, neon It is about 85 to 90V in AC type PDP of magnesium oxide protective film using xenon-based gas.

Sine waves, stepped waves, and giant waves have been used as the sustain voltage waveforms of AC-type PDPs. Currently, giant waves with small internal resistance and rapid rise are known to increase wall voltage. It is written.

When it goes from t0 to t1, the polarity of the sustain voltage (Vs) is changed and is combined with the wall voltage (Vw) generated due to the discharge start. Thus, the sum of the two voltages (Vs + Vw) is greater than the discharge start voltage (Vf). The secondary discharge occurs due to the increase, and when the light pulse is generated due to the secondary discharge, the wall charge is reversed.

At t2, the polarity is changed again to start the third discharge, and the third voltage discharge causes the wall voltage Vw to be reversed. At this time, the sustain voltage Vs is not discharged without the help of the wall voltage Vw.

Figure 2a shows the relationship between the sustain voltage Vs and the wall voltage Vw when the cell is in the " on " state, and thus the light output LP. FIG. The relationship between Vs and the wall voltage Vw and the light output LP accordingly are shown.

FIG. 3A is a waveform diagram used to turn the "off" cell "on", and FIG. 3B illustrates a waveform diagram used to turn the "on" cell "off".

As shown in FIG. 3A, a write pulse (Vwr: Write Pulse) among the address pulses is applied between the sustain voltages (Vs) to partially discharge the wall voltage (Vw) that is in the " off " state. As shown in 3b, the erase pulse Ve (erase pulse) of the address pulses is applied, and the wall voltage Vw in the " on " state drops to the 0V level and is in the " off " state.

4 is a waveform diagram showing how the address is applied to electrodes in a 4 * 4 array. Address pulses (write pulses, erase pulses) for displaying information necessary for a panel while a sustain voltage Vs is applied to all cells. Should be

That is, the sustain voltage is applied to all electrodes, but the address pulse is applied only to the B and D electrodes, which waveform "turns on" or "off" cell 6.

Among the various waveforms, the waveform corresponding to cell 6 is waveform B-D, and the waveforms applied to the other 15 cells are A-D and A-C.

However, conventionally, when the power is turned off while watching a PDP television, the power applied to the entire system is cut off at a time, and there is a problem that an afterimage remains on the PDP screen.

Accordingly, the present invention has been made to solve the above problems, and instead of temporarily shutting off the power applied to the entire system at the time of power-off, the PDP screen is sequentially cut off at a predetermined time interval. SUMMARY OF THE INVENTION An object of the present invention is to provide an afterimage removing device and a method thereof when a PDP television is turned off so that no afterimage remains on the screen.

In order to achieve the above object, the afterimage removal apparatus when the PDP television is powered off according to the present invention includes a video signal receiver for receiving a video signal through an antenna, and an analog video signal from the video signal receiver. An A / D conversion unit for converting the data into an A / D conversion unit, a storage unit for receiving and storing A / D converted image data from the A / D conversion unit, and data suitable for delaying and displaying the image data from the storage unit. A buffer unit configured to output the data from the buffer unit, an address voltage generator unit receiving the data from the buffer unit to generate an address voltage, a sustain voltage generator unit generating a sustain voltage, and performing a scan over time to generate a sustain voltage In a PDP television equipped with a scan and sustain voltage generator, the applied power of the video signal receiver is turned on / off. A first switching unit to make; A second switching unit for turning on / off the applied power of the A / D converter; A third switching unit for turning on / off the applied power of the storage unit; A fourth switching unit for turning on / off the applied power of the buffer unit; A fifth switching unit for turning on / off the applied power of the address voltage generator; A sixth switching unit for turning on / off the applied power of the sustain voltage generating unit; A seventh switching unit for turning on / off the applied power of the scan and sustain voltage generators; A power off signal generator for generating a power off signal when the power is turned off; When the power-off signal from the power-off signal generator is input, each of the switching unit, the fifth switching unit, the sixth and seventh switching units, the fourth switching unit, the third switching unit, and the second switching unit The apparatus may include a power off sequence control unit configured to control a power off sequence of the respective switching units according to a clock signal to turn off the power in the order of the first switching unit.

In addition, the afterimage removal method according to the present invention during the power-off of the PDP telephony is performed by the address voltage generator to turn off the applied power so that the address voltage is not generated when the power is turned off, and after the first step, the scan is not performed. A second step of turning off the applied power of the sustain voltage generator and the scan and sustain voltage generator so as not to generate the sustain voltage; and a third step of turning off the applied power of the buffer unit so that the image data is not delayed after the second step; A fourth step of turning off the applied power of the storage unit such that the image data is not stored after the third step; and a fifth step of turning off the applied power of the A / D converter so that the A / D conversion is not performed after the fourth step. And a sixth step for turning off the applied power of the video signal receiver so that the video signal after the fifth step is not received.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5 is a block diagram of a PDP television to which an embodiment of the present invention is applied, wherein the PDP television includes a video signal receiver 10 for receiving a video signal through an antenna, and an analog video signal from the video signal receiver 10. An A / D converter 14 for receiving an A / D converted image data, a storage unit 18 for receiving and storing A / D converted video data from the A / D converter 16, and the video. A synchronization signal separating unit 22 which receives an image signal from the signal receiving unit 10, separates the synchronization signal, and outputs the synchronization signal to the storage unit 18, and displays after delaying the image data from the storage unit 18. A buffer unit 24 for outputting data suitable for the following; an address voltage generator 28 for receiving data from the buffer unit 24 and generating address voltages (write pulses and erase pulses); Keep generating Vs) A voltage generator 32, a scan and sustain voltage generator 36 that scans according to time and generates a sustain voltage Vs, the sustain voltage generator 32, and the scan and sustain voltage generator The plasma display panel (PDP) 40 which displays the necessary data by applying the address voltage from the address voltage generator 28 while the sustain voltage Vs from the 36 is applied to all cells. It is.

In addition, the afterimage removal apparatus when the power of the PDP telephony according to an embodiment of the present invention is turned off, the first switching unit 12 for turning on / off the applied power (Vcc) of the image signal receiving unit 10; A second switching unit 16 for turning on / off the applied power source Vcc of the A / D converter 14; A third switching unit 20 for turning on / off an applied power source Vcc of the storage unit 18; A fourth switching unit 26 for turning on / off the applied power of the buffer unit 24; A fifth switching unit 30 for turning on / off the applied power source Vcc of the address voltage generator 28; A sixth switching unit 34 for turning on / off the applied power source Vcc of the sustain voltage generating unit 32; A seventh switching unit 38 for turning on / off the applied power source Vcc of the scan and sustain voltage generator 36; A power off signal generator 42 generating a power off signal when the power is turned off; When the power-off signal from the power-off signal generator 42 is input, each of the switching units 12 to 38 may include the fifth switching unit 30, the sixth and seventh switching units 34 and 38, According to a clock signal to turn off the power in order of the fourth switching unit 26, the third switching unit 20, the second switching unit 16, and the first switching unit 12. It is comprised by the power-off order control part 44 which controls the power-off order of each said switching part 12-38.

6 is a flowchart illustrating a method for removing afterimages when the PDP television is powered off according to an embodiment of the present invention, wherein the method for removing afterimages when the power is turned off includes generating a power off signal when the power is turned off; Step S2 of generating a control signal for controlling the order of power supply Vcc off; step S3 of turning off the applied power supply Vcc of the address voltage generator so as not to generate an address voltage according to the control signal generated in step S2; In step S4 of turning off the sustain voltage generating unit and the applied power supply Vcc of the scan and sustain voltage generating unit so that the scan is not performed and the sustain voltage Vs is not generated according to the control signal generated in the step S2; Step S5 of turning off the applied power supply (Vcc) of the buffer unit in order not to delay the video data in accordance with the control signal generated in the step, and the control scene generated in the step S2 According to the control signal generated in the step S2, and the applied power supply Vcc of the A / D converter so that the A / D conversion is not performed according to the control signal generated in the step S2. S7 step of turning off and S8 step of turning off the applied power (Vcc) of the video signal receiver so that the video signal is not received according to the control signal generated in the step S2.

The operation and effects of the afterimage removal apparatus when the PDP television is powered off according to an embodiment of the present invention configured as described above will be described in detail.

First, when the viewer turns off the power of the PDP television, the power-off signal generator 42 generates a power-off signal and outputs it to the power-off sequence control unit 44 (S1).

After the step S1, the power-off sequence control section 44, when the power-off signal from the power-off signal generator 42 is inputted, each of the switching units 12 to 38 switches from the fifth switching unit 30 to the sixth and sixth stages. 7 Turn off the power supply Vcc in the order of the switching sections 34 and 38 → the fourth switching section 26 → the third switching section 20 → the second switching section 16 → the first switching section 12. In response to the clock signal, a control signal for controlling the power-off order of the switching units 12 to 38 is generated and output to the switching units 12 to 38 (S2).

After the step S2, the fifth switching unit 30 turns off the applied power Vcc of the address voltage generator 28 according to a control signal from the power-off sequence control unit 44 so that no address voltage is generated (S3). ).

After the step S3, the sixth switching unit 34 and the seventh switching unit 38 perform the sustain voltage generating unit 32 and the scan and sustain voltage generating unit 36 according to a control signal from the power-off sequence control unit 44. Each applied power supply (Vcc) is turned off so that scanning is not performed and sustain voltage (Vs) is not generated (S4).

After the step S4, the fourth switching unit 26 turns off the applied power supply Vcc of the buffer unit 24 according to the control signal from the power-off sequence control unit 44 so that the image data is not delayed (S5).

After the step S5, the third switching unit 20 turns off the applied power Vcc of the storage unit 18 according to the control signal of the power-off sequence control unit 44 so that the image data is not stored (S6).

After the step S6, the second switching unit 16 turns off the applied power Vcc of the A / D converter 14 according to a control signal from the power-off sequence control unit 44 so that A / D conversion is not performed. (S7).

After the step S7, the first switching unit 12 turns off the applied power Vcc of the image signal receiving unit 10 according to the control signal from the power-off sequence control unit 44 so that the image signal is not received (S8). .

As described above, when the address voltage generator 28, the sustain voltage generator 32, and the scan and sustain voltage generator 36 are directly connected to the plasma display panel PDP 40 to generate various driving voltages. If the applied power supply (Vcc) is turned off first, then the power to other components is turned off in order so that no afterimage remains on the PDP screen.

As described above, according to the present invention, since the applied power of each system is sequentially cut off from the components directly connected to the PDP at a predetermined time interval when the power is turned off, there is an effect that the afterimage does not remain on the PDP screen.

Claims (2)

A video signal receiver for receiving a video signal through an antenna, an A / D converter for receiving an analog video signal from the video signal receiver and converting it into a digital video signal, and A / D conversion from the A / D converter. A storage unit for receiving and storing the received image data, a buffer unit for delaying and outputting the image data from the storage unit as data suitable for display, and an address for receiving the data from the buffer unit and generating an address voltage. A PDP television comprising a voltage generator, a sustain voltage generator for generating a sustain voltage, and a scan and sustain voltage generator for scanning over time and generating a sustain voltage, wherein the applied power of the image signal receiver is turned on. A first switching unit to turn on / off; A second switching unit for turning on / off the applied power of the A / D converter; A third switching unit for turning on / off the applied power of the storage unit; A fourth switching unit for turning on / off the applied power of the buffer unit; A fifth switching unit for turning on / off the applied power of the address voltage generator; A sixth switching unit for turning on / off the applied power of the sustain voltage generating unit; A seventh switching unit for turning on / off the applied power of the scan and sustain voltage generators; A power off signal generator for generating a power off signal when the power is turned off; When the power-off signal from the power-off signal generator is input, each of the switching units includes the fifth switching unit, the sixth and seventh switching units, the fourth switching unit, the third switching unit, and the second switching unit. And a power-off sequence control unit for controlling the power-off sequence of each of the switching units according to a clock signal to turn off the power in the order of the first switching unit. A first step of turning off the power supply of the address voltage generator so that the address voltage is not generated when the power is turned off; and a holding voltage generator and the scan and sustain voltage so that a scan is not performed and a sustain voltage is not generated after the first step. A second step of turning off the applied power of the generator; a third step of turning off the applied power of the buffer so that the image data is not delayed after the second step; and an applied power of the storage part so that the image data is not stored after the third step. A fourth step of turning off the power supply, a fifth step of turning off the applied power of the A / D conversion part so that the A / D conversion is not performed after the fourth step, and a video signal receiving part so that the image signal is not received after the fifth step. And a sixth step of turning off the power supply of the PDP television.