KR19980074918A - Method of driving an AC plasma display panel - Google Patents

Abstract

The present invention relates to a plasma display panel in which N horizontal electrode lines formed on an AC plasma display panel (hereinafter referred to as an AC PDP) are divided into ^2X-1 : ^2X-2 : : 2 ¹ : 2 ⁰ block, and then the first to X-th subframes each consisting of N horizontal electrode lines from the first horizontal electrode line included in each block to the immediately preceding horizontal electrode line frame from the first horizontal electrode lines included in the first to the X th frame, Sequentially scans X lines for each frame, and scans the bit values of the M digital image data corresponding to the currently scanned horizontal electrode lines to M vertical electrode lines formed on the AC PDP to generate 2 ^{The present invention} relates to a driving method of an AC PDP for displaying an ^X- gradation image, and it is possible to minimize the time (address period) required for scanning a horizontal electrode line in one frame to increase the efficiency of the AC PDP. And the contour noise of the screen can be reduced because the upper bit of the digital image data is supplied and the screen having the longer discharge time and the lower bit are supplied and the screen having the shorter discharge time is appropriately mixed There is an effect.

Description

Method of driving an AC plasma display panel

The present invention relates to a driving method of an AC plasma display panel (hereinafter referred to as an AC PDP), and more particularly to a driving method of an AC PDP in which one frame is divided into X subframes and driven.

2. Description of the Related Art In general, a plasma display panel (hereinafter referred to as a PDP) is a kind of light-emitting device that displays an image by utilizing a gas discharge phenomenon occurring inside each discharge cell. The PDP is simple in manufacturing process, A direct display type display device having a large screen with a high response speed is attracting attention as a display device of an image display device aiming at the HDTV (High Definition Television) age in particular.

In addition, an AC (Alternating Current) PDP is driven by a sinusoidal AC voltage or a pulse voltage of the PDP.

M of vertical electrode lines as the AC PDP is shown in Fig. _{1 (D 1, D 2,} ..., D M-1, D M) and N horizontal electrode lines _{(S 1, S 2, ...} , S N _-1 , and S _N are arrayed at predetermined intervals, and the entire screen is composed of M × N cells in the form of a matrix. That is, since the intersection of any vertical and horizontal electrode lines corresponds to one cell, the entire screen is made up of M × N cells.

In addition, in the AC PDP, a voltage applied between a certain vertical electrode line and a horizontal electrode line is adjusted to discharge the corresponding cell, and the discharge sustaining time of each cell is adjusted to control the gray level of the image displayed in each cell scale is implemented.

An addressing and display system (ADS) subfield scheme, which is one of the driving methods of the AC PDP according to the related art, will be described as follows.

First, a process of displaying an image of 16 (2 ⁴ ) gradation on an AC PDP in which 20 vertical electrode lines and 15 horizontal electrode lines are formed is described as an example to facilitate understanding of the ADS subfield method.

In the ADS subfield scheme, one frame is divided into a plurality of subfields to be driven according to gray levels to be implemented, and each subfield is driven to be divided into an address period and a sustain period.

Here, since the address periods of the respective subfields are all assigned equally, the sustain periods are assigned differently according to the bit weights of the digital image data supplied through the plurality of vertical electrode lines. Therefore, the combination of the subfields It is possible to realize gradation of an image.

Therefore, analog image data input from the outside for the implementation of 16 gradations is digitized into 4-bit digital image data (lowest B ₁ to highest B ₄ ), and one frame is divided into four subfields SF _{1 to} SF ₄ ), and the sustain periods of the subfields SF _{1 to} SF ₄ are allocated at a ratio of 2 ⁰ : 2 ¹ : 2 ² : 2 ³ as shown in FIG.

More specifically, in the address period of each of the subfields SF _{1 to} SF ₄ , an erase pulse is applied to all the horizontal electrode lines S ₁ , S ₂ , ..., S ₁₄ , and S ₁₅ in one step, A wall charge is formed in the discharge space of the entire cell by repeating the steps of turning on and off the entire screen by supplying an erase pulse in three steps of writing, sequentially supplying scan (scan) pulse to the electrode line (S ₁ ~S ₁₅₎ and one for scanning the 15 horizontal electrode lines (S ₁ ~S ₁₅₎ sequentially.

In addition, the electrode 15 of the horizontal line in the above step 4 (S ₁ ~S ₁₅₎ 20 of the vertical electrode lines during the one that is scanned sequentially _{(D 1, D 2, ...} , D 19, D 20) , the scan pulse and the sync (A 1-bit value of the digital image data) supplied to the address electrode, so that the address discharge is generated within the discharge space of each cell supplied with the logic high as the address pulse.

At this time, among four bits of digital image data (B _{1 to} B ₄ ) corresponding to each cell, B _{1 is set} to SF ₁ , B ₂ to SF ₂ , B ₃ to SF ₃ , and B ₄ to SF ₄ Supply.

On the other hand, each sub-field when the address period is completed, the (SF ₁ ~SF ₄₎ to supply the sustain pulse to the electrode 15 of the horizontal line (S ₁ ~S ₁₅₎ period of the sustain pulse is applied to the discharge and light emission of each cell (Sustain period).

At this time, each subfield (SF ₁ ~SF ₄₎ has _{SF 1: SF 2: SF 3} : SF 4 = 2 0: 2 1: 2 2: supplies the sustain pulses of the number proportional to ^23.

When the sustain period of the last subfield SF ₄ is completed through the above process, a gray level image of one frame is displayed on the AC PDP.

For example, 1 + 2 + 4 = 7 gradations are implemented for cells supplied with digital image data 0111 over the first to fourth subfields SF _{1 to} SF ₄ , and cells supplied with 1100 are 4 + 8 = 12 gray scales are implemented, and 1 + 2 + 4 + 8 = 15 gray scales are implemented for 1111 cells.

On the other hand, an AC PDP for an HDTV requires 256 gradations and a resolution of 1280 x 1024 or more, and a contrast of 100: 1 or more is required under 200 lux illumination. In order to display an image of 256 gradations, 8 bits of R (Red), G (Green) and B (Blue) digital image data are required for color display. In order to obtain the brightness and contrast required for HDTV, Discharge time should be kept as long as possible.

However, since the AC PDP is driven in a matrix manner, there is a restriction that a scan pulse can not be applied to two or more horizontal electrode lines at a time. That is, when a scan pulse is applied to two or more horizontal electrode lines at a time, the same image is displayed on each horizontal electrode line to be simultaneously scanned, so that a scan pulse must be applied to only one horizontal electrode line at a time.

Therefore, each horizontal electrode line needs to be scanned at a different time. In order to configure each sub-field screen, a time (address period) for scanning all the horizontal electrode lines is required. Each cell has a time The discharge and light emission of each cell can be maintained only for a time corresponding to the scanning time of the horizontal electrode lines.

The time required for scanning increases as the number of horizontal electrode lines increases. Since the discharge of each cell can not be maintained during this time, the efficiency, brightness, and contrast of the AC PDP are reduced. Time should be reduced as much as possible.

In the method of driving an AC PDP according to the related art, a difference in discharge time is large between subfields to which upper bits of digital image data are supplied and subfields to which lower bits are supplied, Field screens are sequentially formed, contour noise due to difference in discharge time of each subfield is seriously generated.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems of the conventional art, and it is an object of the present invention to reduce the time (address period) required for scanning horizontal electrode lines in one frame and increase the time (sustain period) And an object of the present invention is to provide a driving method of an AC PDP capable of increasing the efficiency, brightness and contrast of a PDP.

The present invention also relates to a driving method of an AC PDP capable of reducing outline noise of a screen by arranging a screen having a long discharge time and a low-bit time and a short discharge time in a proper order by supplying upper bits of digital image data There is another purpose in providing.

1 is an electrode structure diagram of a general AC plasma display panel (hereinafter, referred to as an AC PDP)

FIGS. 2 and 3 illustrate a 16-gradation implementation using the prior art,

FIGS. 4 and 5 illustrate a 16-gradation implementation using an embodiment of the present invention.

According to another aspect of the present invention, there is provided a method of driving an AC PDP, the method comprising: applying an AC voltage to an AC plasma display panel (hereinafter referred to as an AC PDP) having M vertical electrode lines and N horizontal electrode lines, A method for displaying an image of 2 ^x gray scale by supplying digital image data (lowest B ₁ to highest B _x ), the method comprising: dividing the N horizontal electrode lines into 2 ^X-1 : 2 ^X-2 : : 2 ¹ : 2 ⁰ block, and then the first to X-th subframes each consisting of N horizontal electrode lines from the first horizontal electrode line included in each block to the immediately preceding horizontal electrode line frame from the first horizontal electrode lines included in the first to the X th frame, Frame for each X-line and after sequentially erasing the scanning with the image of the 2 ^X gray level value of the bit of the M digital image data corresponding to the horizontal electrode lines that are scanned onto the AC PDP is supplied to the M number of vertical electrode lines by Is displayed.

When the horizontal electrode line included in the first sub-frame is scanned, the least significant bit value B ₁ of M digital image data corresponding to each horizontal electrode line is supplied. In the case of the second sub-frame, the most significant bit value B _X , the third, fourth, ... , X-1, bit values B _X-1 , B _X-2 , ... in the case of the Xth sub-frame. , B ₃ and B ₂ , respectively.

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

The driving method of an AC PDP according to an embodiment of the present invention includes 20 vertical electrode lines D ₁ , D ₂ , ..., D ₁₉ , D ₂₀ and 15 horizontal electrode lines S ₁ , S ₂ , ..., S _14, S ₁₅₎ a method of displaying a picture of the 16 ⁽²⁴⁾ is formed by gray-scale one frame supplied to the digital image data (the least significant B ₁ ~ B ₄ top) of 4 bits for the AC PDP.

More specifically, as shown in FIG. 4, 15 horizontal electrode lines (S _{1 to} S ₁₅ ) formed on an AC PDP are divided into four blocks of 2 ³ : 2 ² : 2 ¹ : 2 ⁰ ratio S ₁₅ , S ₈ , S ₁₂ , and S ₁₄ positioned immediately before the first horizontal electrode lines (S ₁ , S ₉ , S ₁₃ , and S ₁₅ ) First to fourth subframes (sf ₁ , sf ₂ , sf ₃ , sf ₄ ) composed of horizontal electrode lines are constituted,

The wall charge is formed in the discharge space of all the cells by repeating the process of turning on and off the entire screen to form wall charges in the first horizontal subframe (sf ₁ , sf ₂ , sf ₃ , sf ₄ ) S ₁₅ , S ₈ , S ₁₂ , S ₁₄ ) from the electrode lines (S ₁ , S ₉ , S ₁₃ , S ₁₅ ) A frame (hereinafter referred to as one horizontal period ") every 4 lines by 20-bit value to the 20 vertical electrode lines of the digital image data corresponding with the scanning and after sequentially erased in the horizontal electrode lines are scanned (D ₁ ~ D ₂₀ to display an image of 16 (2 ⁴ ) gradations on the AC PDP.

In each block, the horizontal electrode lines S _{1 to} S ₈ , the horizontal electrode lines S _{9 to} S 12, the horizontal electrode lines S _{9 to} S ₁₂ , the horizontal electrode lines S ₁₃ and S ₁₄ , _14), 15 horizontal electrode line (S ₁₅₎ is included, so each of the first sub-frame (sf ₁₎ has 15 horizontal lines in the order from the electrode number 1 to 15 (S ₁ ~S ₁₅₎ the second sub frame (sf _2), in this order from 9 to 8 to 15 horizontal line electrodes (S ₉ ~S ₈₎ the third subframe (sf ₃₎ has in the order from 13 to 12 times the horizontal electrode lines 15 (S ₁₃ ~S ₁₂₎ is the fourth sub-frame is (sf ₄₎ contains in the order of 15 times to 14 times of 15 horizontal line electrodes (S ₁₅ ~S _14), respectively.

The scanning order of each of the horizontal electrode lines S _{1 to} S ₁₅ described above is summarized in Table 1 below.

[Table 1]

The horizontal cycle sf One 2 3 4 5 6 7 8 9 10 11 12 13 14 15 sf ₁ S ₁ S ₂ S ₃ S ₄ S ₅ S ₆ S ₇ S ₈ S ₉ S ₁₀ S ₁₁ S ₁₂ S ₁₃ S ₁₄ S ₁₅ sf ₂ S ₉ S ₁₀ S ₁₁ S ₁₂ S ₁₃ S ₁₄ S ₁₅ S ₁ S ₂ S ₃ S ₄ S ₅ S ₆ S ₇ S ₈ sf ₃ S ₁₃ S ₁₄ S ₁₅ S ₁ S ₂ S ₃ S ₄ S ₅ S ₆ S ₇ S ₈ S ₉ S ₁₀ S ₁₁ S ₁₂ sf ₄ S ₁₅ S ₁ S ₂ S ₃ S ₄ S ₅ S ₆ S ₇ S ₈ S ₉ S ₁₀ S ₁₁ S ₁₂ S ₁₃ S ₁₄

On the other hand, each of the horizontal electrode lines (S ₁ ~S ₁₅₎ 20 bits values of the digital image data supplied to the electrode 20 of the vertical line (D ₁ ~D ₂₀₎ when this is to be scanned in the first sub-frame ₍₁ sf) The most significant bit B ₁ for the second subframe sf ₂ , the _fourth most significant bit B ₄ for the third subframe sf ₃ , the third bit B ₃ for the third subframe sf _3, ), The second bit B ₂ is supplied.

Accordingly, one frame (horizontal period 1 to 15) for example, look at each horizontal electrode lines horizontal electrode lines (S _1), the bit values of the digital image data to be supplied to 1 (S ₁ ~S ₁₅₎ by way of example in Table 1 above. 1 times the horizontal electrode lines (S ₁₎ is 1, 2, 4, respectively, scanning the 8 horizontal period there is the digital image data of 4 bits is supplied bit by bit, one horizontal period, the bit weight 2 ⁰ = B ₁ having a first Is emitted and maintained for one horizontal period until it is scanned again in two horizontal periods and two horizontal periods are supplied with B ₂ having a bit weight of 2 ¹ = The emission is maintained during the horizontal period, the emission is maintained during four horizontal periods until four horizontal periods are supplied with B ₃ having a bit weight of 2 ² = 4 to be scanned again in eight horizontal periods, and 8 horizontal periods are provided with bit weights B ₄ a ball having a 2 ⁴ = 8 Since the discharge is maintained for eight single horizontal period until re-scanned in one horizontal period of the next frame, the 20 cells corresponding to the horizontal electrode lines (S ₁₎ is 1 16-gradation image is displayed.

In addition, the same principle is applied to the _second to _fifteenth horizontal electrode lines (S _{2 to} S ₁₅ ), and 16-gradation images are displayed in 20 cells corresponding to each of them.

Unlike the ADS subfield method of the related art, when the AC PDP is driven according to the embodiment of the present invention described above, it is possible to reduce the time required to construct the screen of each subframe sf ₁ , sf ₂ , sf ₃ , sf ₄ 5), the time required to scan each horizontal electrode line is greatly reduced compared to the prior art and the efficiency becomes almost 90% or more, and the scanning time which is less than the prior art (as a result, Quot;) is allocated to the discharge sustaining, the luminance and contrast of the entire screen can be increased.

In addition, the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit and scope of the invention.

As described above, the present invention minimizes the time (address period) required for scanning the horizontal electrode lines in one frame, thereby increasing the efficiency of the AC PDP. Therefore, the luminance and contrast of the entire screen can be increased, Bits are supplied and a screen having a long discharging time and a screen having a short discharging time are supplied with low-order bits, so that the contour noise of the screen can be reduced.

Claims (2)

Alternating-current plasma display panel (hereinafter, AC PDP ") the digital image data (the least significant B ₁ ~ top B _X) of X bits supplied during the first frame to 2 ^X gradation are M vertical electrode lines and N number of horizontal electrode lines formed 1. A method of displaying an image on a gray scale, 2 ^X-1 : 2 ^X-2 : : 2 ¹ : 2 ⁰ block, and then the first to X-th subframes each consisting of N horizontal electrode lines from the first horizontal electrode line included in each block to the immediately preceding horizontal electrode line subframe) From the first horizontal electrode lines included in the first to the X th subframes to the last Nth horizontal electrode lines Frame for each X-line and after sequentially erasing the scanning with the image of the 2 ^X gray level value of the bit of the M digital image data corresponding to the horizontal electrode lines that are scanned onto the AC PDP is supplied to the M number of vertical electrode lines by Is displayed on the liquid crystal display panel. The method according to claim 1, Frame, when the horizontal electrode line included in the first sub-frame is scanned, supplies the least significant bit value B ₁ of M digital image data corresponding to each horizontal electrode line, and supplies the most significant bit value B _X , The third, fourth, ... , X-1, bit values B _X-1 , B _X-2 , ... in the case of the Xth sub-frame. , B ₃ , and B ₂ are respectively supplied to the electrodes.