KR20080046497A - Apparatus for driving display panel - Google Patents

Abstract

An apparatus for driving a display panel is provided to reduce a component mounting area by supplying high and low scan bias voltages and a falling minimum voltage using a DC/DC converter. A discharge display apparatus includes a discharge display panel(1), drivers(53,54,55), a controller(62), and a power supply unit(61). The drivers apply driving signals to X, Y, and address electrode lines of the discharge display panel. The controller generates driving control signals to drive the drivers. The power supply unit supplies driving DC voltages to the drivers and the controller. The power supply unit includes a DC/DC(Direct Current) converter, which generates high and low scan bias voltages and a falling minimum voltage by converting a driving DC sustain discharge voltage.

Description

Apparatus for driving display panel

1 is an internal perspective view showing the structure of a plasma display panel of a three-electrode surface discharge method as a conventional discharge display panel.

FIG. 2 is a cross-sectional view illustrating an example of one display cell of the panel of FIG. 1.

3 is a timing diagram showing a driving method in the discharge display device according to the present invention.

4 is a waveform diagram of signals applied to electrode lines of the plasma display panel of FIG. 1 in a unit sub-field of FIG. 3.

5 is a block diagram showing a plasma display device as a discharge display device according to the present invention.

FIG. 6 is a block diagram illustrating a configuration of an integrated DC-DC converter applied to a Y driver of the power supply of FIG. 5.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for a display panel, and more particularly, to a discharge display panel, driving units for applying driving signals to respective electrode lines of the discharge display panel, and driving control signals for operating the driving units. And a power supply unit for supplying driving DC power to the driving units and supplying operating DC power to the driving units and the control unit.

As flat panel display devices, plasma display panels (PDPs), which are easy to manufacture large panels, have attracted attention. A plasma display panel is a display device that displays an image by using a discharge phenomenon. In general, a plasma display panel can be classified into a direct current type and an alternating current type according to the type of driving voltage. Due to the disadvantages, the development of the AC plasma display panel has been made a lot.

An AC plasma display panel includes a three-electrode AC surface discharge type plasma display panel having three electrodes and driven by an AC voltage. A typical three-electrode surface discharge type plasma display panel is composed of a multi-layered plate, which is spatially advantageous because it can provide a thinner, lighter, and wider screen than a conventional cathode ray tube (CRT).

FIG. 1 shows the structure of a three-electrode surface discharge plasma display panel as a conventional discharge display panel. FIG. 2 shows an example of one display cell of the panel of FIG. 1. 1 and 2, between the front and rear glass substrates 10 and 13 of the conventional surface discharge plasma display panel 1, address electrode lines A _R1 ,..., A _Bm , a dielectric layer. (11, 15), Y electrode lines (Y ₁ , ..., Y _n ), X electrode lines (X ₁ , ..., X _n ), phosphor 16, partition 17 and protective layer As a magnesium monoxide (MgO) layer 12 is provided.

The address electrode lines A _R1 ,..., A _Bm are formed in a predetermined pattern on the front side of the rear glass substrate 13. The lower dielectric layer 15 is applied to the entire surface in front of the address electrode lines A _R1 ,..., A _Bm . In front of the lower dielectric layer 15, barrier ribs 17 are formed in a direction parallel to the address electrode lines A _R1 ,..., And A _Bm . These partitions 17 function to partition the discharge area of each display cell and prevent optical cross talk between each display cell. The fluorescent layer 16 is applied between the partition walls 17.

The X electrode lines (X ₁ , ..., X _n ) and the Y electrode lines (Y ₁ , ..., Y _n ) intersect the address electrode lines (A _R1 , ..., A _Bm ). It is formed in a constant pattern on the back of the front glass substrate 10. Each intersection sets a corresponding display cell. Each X electrode line (X ₁ , ..., Xn) and each Y electrode line (Y ₁ , ..., Y _n ) is a transparent electrode line of a transparent conductive material such as indium tin oxide (ITO) or the like (see FIG. 2). X _na , Y _na ) and a metal electrode line (X _nb , Y _nb of FIG. 2) for increasing conductivity are formed. The front dielectric layer 11 is formed by applying the entire surface to the rear of the X electrode lines (X ₁ ,..., X _n ) and the Y electrode lines (Y ₁ , ..., Y _n ). A protective layer 12 for protecting the panel 1 from a strong electric field, for example, a magnesium monoxide (MgO) layer, is formed by applying the entire surface to the back of the front dielectric layer 11. The plasma forming gas is sealed in the discharge space 14.

In the driving method (see US Pat. No. 5,541,618) basically applied to such a plasma display panel, the resetting, addressing, and sustaining-discharge steps are sequentially performed in the unit subfield. Is performed. In the resetting phase, the charge states of all display cells are uniform. In the addressing step, a predetermined wall voltage is generated in the selected display cells. In the sustain-discharge step, a predetermined alternating voltage is applied to all the XY electrode line pairs so that the display cells in which the wall voltage is formed in the addressing step cause sustain-discharge. In this sustain-discharge step, a plasma is formed in the discharge space 14 of the selected display cells causing the sustain-discharge, that is, the gas layer, and the fluorescent layer 16 is excited by the ultraviolet radiation to generate light.

The driving device of the discharge display panel is provided with driving units (X driving unit, Y driving unit and address driving unit), a control unit, and a power supply unit. The drivers apply driving signals to respective electrode lines of the discharge display panel. The controller generates driving control signals through which the driving units can operate. The power supply unit supplies driving DC power supplies to the driving units, and supplies operating DC power supplies to the driving units and the control unit.

In the case of the conventional driving _units , the scan high potential (V _SCANH ), the scan low potential (V _SCANL ), and the DC falling lowest potential (V _NF ) applied to the power supply unit are set to 2-3 DC- A DC converter (DC-DC converter) was applied and supplied. In this case, there is a problem in that various disadvantageous conditions occur such that the cost of the parts is disadvantageous and the parts are largely occupied in PCB fabrication.

The technical problem to be achieved by the present invention is to provide a driving device of a display panel to reduce the cost and reduce the component mounting area of the driving unit by supplying various potentials required for the Y driving unit using a single DC-DC converter.

According to an aspect of the present invention, a display panel driving apparatus includes a discharge display panel, driving units for applying driving signals to X, Y and address electrode lines of the discharge display panel, and the driving units may operate. A discharge display device comprising: a control unit for generating drive control signals; and a power supply unit supplying driving DC potentials to the driving units and supplying operating DC potentials to the driving units and the control unit. The unit transforms the driving DC sustain-discharge potential (V _S ) to generate and output a DC high scan-bias potential (V _SCANH ), a DC low scan-bias potential (V _SCANL ), and a DC falling minimum potential (V _NF ). It is preferable to include a DC-DC converter.

In the present invention, the DC-DC converter converts the sustain-discharge potential V _S according to a pulse width modulated signal and inputs the plurality of primary coils to form a first to third alternating current induced in the plurality of secondary coils. A transformer for outputting power; A rectifier circuit rectifying the 1-3 AC power output from the transformer to a 1-3 DC potential; A buck converter outputting a high scan-bias potential V _SCANH by averaging pulse potentials which are periodically cut out of the first DC potential output from the rectifier circuit; A regulator configured to maintain the falling lowest potential (V _NF ) as the second DC potential output from the rectifier circuit at a constant potential to be output; A photocoupler for detecting on / off of a low scan-bias power source (V _SCANL ) as the third DC potential output from the rectifier circuit; And a pulse width modulation control unit generating a pulse width modulation signal as an output signal of the photo coupler to control output of the first to third AC power sources of the transformer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, the plasma display panel as the display panel included in the display device of the present invention has been described with reference to FIGS. 1 and 2.

3 shows a driving method in the plasma display device as the discharge display device according to the present invention. Referring to FIG. 3, each unit frame is divided into _eight subfields SF ₁ ,..., SF ₈ to realize time division gray scale display. In addition, each subfield SF ₁ , ..., SF ₈ has a resetting time R ₁ , ..., R ₈ , an addressing time A ₁ , ..., A ₈ , and a holding- It is divided into discharge times S ₁ , ..., S ₈ .

The discharge conditions of all the display cells become uniform at each reset time R ₁ ,..., R ₈ , while being adapted to the addressing to be performed in the next step.

Each addressing time _{(A 1, ..., A 8} ), the address electrode lines (Fig. 1 A _R1, ..., A _Bm) display data signals are applied at the same time as soon each Y electrode lines in the (Y _1, ..., Y _n ), the scanning pulses are sequentially applied. Accordingly, when high level display data signals are applied while the scan pulse is applied, wall charges are formed by the addressing discharge in the corresponding discharge cell, and wall charges are not formed in the discharge cell that is not.

At each sustain-discharge time (S ₁ , ..., S ₈ ), all Y electrode lines (Y ₁ , ..., Y _n ) and all X electrode lines (X ₁ , ..., X _n) Sustain-discharge pulses are alternately applied, causing display discharge in discharge cells in which wall charges are formed at corresponding addressing times A ₁ ,..., A ₈ . Therefore, the luminance of the plasma display panel is proportional to the length of the sustain-discharge time S ₁ ,..., S ₈ occupied in the unit frame. The length of the sustain-discharge time S ₁ , ..., S ₈ occupied in the unit frame is 255T (T is the unit time). Therefore, it can be displayed in 256 gray levels, including the case where it is not displayed once in a unit frame.

Here, the time 1T corresponding to 2 ⁰ is the sustain-discharge time S ₁ of the first subfield SF ₁ , and the time 1T corresponding to the sustain-discharge time S ₂ of the second subfield SF ₂ is 2. ^The time 2T corresponding to ¹ is maintained in the third subfield SF ₃ -In the discharge time S ₃ , the time 4T corresponding to 2 ² is maintained in the fourth subfield SF ₄ . The discharge time S ₄ has a time 8T corresponding to 2 ³ , and the sustaining-discharge time S ₅ of the fifth subfield SF ₅ has a time 16T corresponding to 2 ⁴ , and the sixth sub field maintenance of the (SF ₆₎ - discharge time (S _6), this time (32T) corresponding to 2 ^5, 7 keep the sub-fields (SF ₇₎ - discharge time period that is equivalent to 2 ⁶ (S ₇₎ 64T and time 128T corresponding to 2 ⁷ are set in the sustain-discharge time S ₈ of the eighth subfield SF ₈ , respectively.

Accordingly, if the subfield to be displayed among the eight subfields is appropriately selected, the display of 256 gray levels can be performed including all zero (zero) gray levels that are not displayed in any of the subfields.

4 illustrates signals applied to electrode lines of the plasma display panel 1 of FIG. 1 in the unit sub-field SF of FIG. 3.

Referring to the drawings, the unit frame of the plasma display panel 1 is divided into a plurality of subfields according to gray scale weights for time division gray scale display driving. Each subfield SF is divided into a reset period PR, an address period PA, and a sustain period PS.

First, in the reset period PR, a reset pulse consisting of a rising pulse and a falling pulse is applied to the Y electrodes Y ₁ to Y _n , and a second voltage is applied to the X electrodes X ₁ to X _n when the falling pulse is applied. (Bias voltage) is applied to perform reset discharge. All discharge cells are initialized by reset discharge. The rising pulse rises from the sustain discharge voltage (Vs) by the rising voltage (V _SET ) and finally reaches the rising maximum voltage (V _SET + V _S ), and the falling pulse falls from the sustain discharge voltage (Vs) and finally falls. The minimum voltage (V _NF ) is reached.

In the address period PA, scanning pulses are sequentially applied to the Y electrodes Y ₁ ,..., And Y _n , and A electrodes A ₁ ,..., A _m are displayed in accordance with the scanning pulses. The data signal is applied to perform address discharge. The discharge cells to be subjected to the sustain discharge occurring in the sustain period PS by the address discharge are selected. The scan pulse has a scan high voltage (V _SCANH ) and sequentially has a scan low voltage (V _SCANL ) whose voltage is smaller than the scan high voltage (V _SCANH ), and the display data signal is the scan low voltage (V _SCANL ) of the scan pulse. At the time of application, it has a positive address voltage Va.

In the sustain period PS, sustain pulses are alternately applied to the X electrodes X ₁ to X _n and the Y electrodes Y ₁ to Y _n to perform sustain discharge. Luminance is expressed according to the gray scale weight allocated to each subfield by the sustain discharge. In each of the discharge cells, sustain discharge is caused in the selected discharge cells by the number of sustain pulses according to the gray scale weight.

4 and 5, a plasma display device as a display device according to the present invention includes a plasma display panel 1, an image processor 56, a controller 62, an address driver 53, an X-driver 54, Y-drive section 65, and power supply 61.

The plasma display panel 1 has been described with reference to FIGS. 1 and 2. The image processing unit 56 converts an external analog image signal into a digital signal to convert an internal image signal, for example, 8-bit red (R), green (G), and blue (B) image data, a clock signal, vertical and horizontal, respectively. Generate sync signals. The controller 62 generates driving control signals S _A , S _Y , and S _X according to an internal image signal from the image processor 56.

The address driver 53 processes the address signal S _A among the driving control signals S _A , S _Y , and S _X from the controller 62 to generate display data signals, and generates the generated display data signals. It is applied to the address electrode lines (A _R1 , A _G1 ,..., A _Gm , A _Bm in FIG. 1). The X-drive unit 54 processes the X drive control signal S _X among the drive control signals S _A , S _Y , and S _X from the control unit 62 to process the X electrode lines (X ₁ , ... apply to X _n ). The Y-drive unit 55 processes the Y driving control signal S _Y among the driving control signals S _A , S _Y , and S _X from the control unit 62 to Y electrode lines (Y ₁ , ... applied to Y _n ).

The power supply unit 61 supplies driving DC potentials V _A , V _SCAN , V _S , V _SET , V _NF , V to each of the driving units 53, 54, 55, the image processing unit 56, and the control unit 62. _GT ) and operating DC potentials (3.3 V, 5 V). More specifically, 5 V operating DC potentials are supplied to the image processing unit 56 and 3.3 V and 5 V operating DC potentials are supplied to the control unit 62. In addition, the sustain-discharge potential (V _S ), the additional potential (V _SET ), the falling lowest potential (V _NF ), the high scan-bias potential (V _SCANH ), and low as the driving DC potentials in the Y-drive part 55. The scan-bias potential V _SCANL is supplied, and the gate operation DC potential v _GT and 5 V (volts) as the operation DC potentials are supplied. In addition, the address driver 53 is supplied with an addressing potential V _A as a driving direct current potential, and a gate operation direct current potential v _GT and 5 V (volts) as an operating direct current potential. The sustain-discharge potential V _S as a driving DC potential is supplied to the X-drive part 54, and the gate operation DC potential v _GT and 5 V (volts) as the operating DC potential are supplied.

In the case of the conventional drivers, for the cost reduction, the falling lowest potential (V _NF ), the high scan-bias potential (V _SCANH ), and the low scan-bias potential (V _SCANL ) applied to the power supply part are applied to the Y-drive part 55. In order to solve the component cost increase and the component area caused by applying the two DC-DC converters provided, as shown in FIG. 6, various potentials required for the Y-drive unit 55 are connected to one DC-DC circuit. Supply using a converter.

Referring to FIG. 6, the transformer 601 receives an input driving sustain-discharge potential V _S as an input by the pulse width modulation signal of the pulse width modulation control unit 606 to the first to third AC power sources. Convert it and print it out. Transformer 601 has two primary side windings N ₁ , N ₂ and three secondary side windings N _2-1 to N _2-3 . When the driving sustain-discharge potential V _S switched by the pulse width modulated signal is input to the two primary side windings N ₁ and N ₂ , three stacked secondary side windings N _2-1 to N _{2 -3} ) and the first to third AC power sources are output by the turns ratio of the primary windings N ₁ and N ₂ .

The rectifier circuit 602 is composed of a plurality of diodes D1 to D3 and a plurality of capacitors C1 to C3, and rectifies the 1-3 AC power to output the first to third DC potentials.

The first to third DC potentials output from the rectifier circuit 602 represent the high scan-bias potential V _SCANH , the lowest falling potential V _NF , and the low scan-bias potential V _SCANL, respectively.

Buck converter 603 includes a first DC potential that is, a high scan output from the rectifier circuit (602) the bias potential (V _SCANH) periodically cut and made an average to a stable DC high scan pulse voltage-bias potential (V _SCANH) It is a constant voltage circuit that outputs. The buck converter 603 is a principle of forming an output potential by averaging a pulse voltage generated by periodically cutting an input DC potential, and the longer the time the switch is turned on within a cycle, the wider the width of the pulse potential is. The shorter the ON time is, the smaller the width of the pulse potential is.

Generally, since the high scan-bias potential V _SCANH is difficult to adjust, conventionally, two or three converters are used, but in the present invention, the high scan-bias potential ( V _SCANH ) will be adjusted.

The regulator 604 receives a second DC potential output from the rectifier circuit 602, that is, the falling lowest potential V _NF , and outputs a constant electrostatic potential.

The photocoupler 605 detects the second DC potential output from the transformer 602, that is, the low scan-bias potential V _SCANL , and outputs a high level signal when the low scan-bias potential V _SCANL is turned on. Outputs a low level signal. That is, the photodiode, which is a display element provided in the photo coupler 605 by recognizing the low scan-bias power source V _SCANL , is turned on or off.

The pulse width modulation control unit 606 receives a high level signal or a low level signal output from the photo coupler 605 as a reference signal to generate a pulse width modulation signal, and the pulse width modulation signal is a driving sustain-discharge potential (V). _S ) is switched to control the output of the first to third AC power supplies of the transformer 601.

According to the present invention, a single DC-DC converter uses various power supplies required for the Y driving unit, that is, the high scan-bias potential V _SCANH , the low scan-bias potential V _SCANL , and the lowest falling potential V _NF . By supplying the components, the component mounting area is reduced and the PCB size can be reduced, which creates the effect of reducing the overall cost.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, it is merely an example, and those skilled in the art may realize various modifications and equivalent other embodiments therefrom. I can understand. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

Claims (2)

A discharge display panel, drivers for applying drive signals to the X, Y and address electrode lines of the discharge display panel, a controller for generating drive control signals for allowing the drivers to operate, and a direct current for driving to the drivers. A discharge display apparatus having a power supply unit supplying potentials and supplying operating DC potentials to the driving units and the control unit. The power supply unit Direct current generating and outputting DC high scan-bias potential (V _SCANH ), DC low scan-bias potential (V _SCANL ) and DC falling lowest potential (V _NF ) by modifying the driving DC sustain-discharge potential (V _S ) for _driving . A driving device of a display panel including a direct current converter. The method of claim 1, wherein the DC-DC converter A transformer for converting the sustain-discharge potential V _S according to a pulse width modulation signal and inputting it to a plurality of primary coils to output a 1-3 AC power induced to a plurality of secondary coils; A rectifier circuit rectifying the 1-3 AC power output from the transformer to a 1-3 DC potential; A buck converter outputting a high scan-bias potential V _SCANH by averaging pulse potentials which are periodically cut out of the first DC potential output from the rectifier circuit; A regulator configured to maintain the falling lowest potential (V _NF ) as the second DC potential output from the rectifier circuit at a constant potential to be output; A photocoupler for detecting on / off of a low scan-bias power source (V _SCANL ) as the third DC potential output from the rectifier circuit; And And a pulse width modulation controller configured to generate a pulse width modulation signal using the output signal of the photo coupler to control the output of the first to third AC powers of the transformer.

Images