KR19990060197A - Method and device for correcting luminance level of 3-electrode surface discharge plasma display panel - Google Patents

Abstract

The present invention relates to a driving apparatus and method for a three-electrode surface discharge plasma display panel (hereinafter referred to as a three-electrode surface discharge PDP).

By dividing one frame into X subfields and adjusting the number of sustain pulses applied to each subfield, the level of brightness represented by each subfield is adjusted. but each representing a dumyeo different weights, wherein each 2 ^X gradation (gray scale) of a combination of X sub-fields having different brightness levels, respectively, SF1 in the X sub-fields: SF2: ~: SFX = 1 : 2: The conventional technique of applying sustain pulses proportional to 2 ^X-1 has a discontinuity phenomenon in luminance levels because the luminance level actually expressed by the discharge characteristics of the cell is not exactly proportional to the number of sustain pulses supplied. To solve the problem,

The present invention compares the difference between the actual luminance level of the subfield represented by the current screen and the predetermined reference level, and adjusts the number of sustain pulses applied to each subfield to obtain continuity of the luminance level. It is done.

Description

Method and device for correcting luminance level of 3-electrode surface discharge plasma display panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for driving a three-electrode surface discharge plasma display panel (hereinafter referred to as a three-electrode surface discharge PDP), and more particularly, to a method of expressing gray scale of an image.

The CRT (Cathode Ray Tube), which has been the mainstay of the display means, scans the electron beam through the entire fluorescent surface with a single electron gun, so the distance between the fluorescent surface and the electron gun must be large.

Due to the above characteristics, CRT is bulky, heavy, difficult to implement a flat screen, and difficult to realize a large screen.

Therefore, in order to overcome the above problems, various display technologies such as LCD, flat vision panel, plasma display pannel (PDP), etc. are thin and light and enable large screen realization.

Among them, the PDP is applied to the surface of the rear substrate by ultraviolet rays generated when a discharge gas is injected between the thin front substrate and the rear substrate on which the plurality of transparent electrodes are formed, and discharged by applying a voltage between the transparent electrodes. The phosphor emits light, and each of the light emitting elements composed of the electrode and the phosphor is formed of cells separated by partition walls, and each of them is driven independently. Not only is it easy to implement a large screen, but also has the advantage of eliminating color bleeding and deterioration of focus, so it has become a focus of attention as a new display means that can overcome the limitation of CRT.

On the other hand, unlike the CRT that controls the gray scale of the screen by adjusting the intensity of the electron beam irradiated to the phosphor, the three-electrode surface discharge PDP (10) is a method of controlling the number of times of discharge due to the difficulty of controlling the intensity of the discharge Use to adjust the gray scale of the screen.

In other words, when a time for displaying one image on the entire screen is one frame, one frame is divided into X sub-fields each of which is discharged in multiples of ¹ to 2 ^X-1 times. Each cell discharges only in a corresponding subfield of each subfield and does not discharge in an unapplied subfield, so that the brightness of each cell is determined according to the combination of the number of discharges in the discharged subfield. It is implemented a gradation (gray scale) of the 2 ^X level.

If the 256-level gradation is implemented as an example,

One frame is divided into eight subfields, and each subfield is proportional to SF1: SF2: SF3: SF4: SF5: SF6: SF7: SF8 = 1: 2: 4: 8: 16: 32: 64: 128 Sustain in the ON subfield by applying a sustain pulse of, so that each cell is ON only in the corresponding subfield among the respective subfields and OFF in an unapplied subfield. 256 levels of gray scale are implemented according to the number of discharges by the pulse.

However, the brightness of the image actually expressed by the discharge characteristics of the cell is not exactly proportional to the number of the sustain pulses.

That is, the actual cell emits light because the moment at which the sustain pulse is applied and the moment at which the cell starts to emit light or the moment at which the sustain pulse is turned off and the moment at which the cell stops emitting light are not exactly the same. The time differs slightly from the sustain pulse interval in a strict sense.

For the same reason, 01111111 ₍₂₎ made by adding several short emission sections (SF1,2,3,4,5,6,7 ₎ and 10000000 ₍₂₎ made by one long emission section (SF8) have considerable luminance. You will see a difference.

In particular, the point where the difference in brightness is severe,

The point that changes from level 7, which is the sum of SF1,2,3, to level 8, which is SF4,

The point that changes from level 15, which is the sum of SF1, 2, 3, and 4, to level 16, which is SF5,

The point that changes from level 31, which is the sum of SF1,2,3,4,5, to 32, which is SF6,

The point that changes from level 63, which is the sum of SF1,2,3,4,5,6, to 64, which is SF7,

It is a point that changes from the level 127 which is the sum of SF1, 2, 3, 4, 5, 6, and 7 to the level 128 which is SF8.

FIG. 1 is a diagram showing the discontinuity of luminance as described above.

In Fig. 1A, the sustain pulses applied in each subfield are shown and the number (2, 4, 8, 16, 32, 64, 128, 256) is displayed.

FIG. 1B illustrates a relationship between a theoretical gray level and luminance actually implemented. The luminance curve 110 showing the discontinuity and the average value 120 of the luminance curve are shown.

The present invention has been made to solve the above-mentioned problems of the prior art, and the number of sustain pulses applied to each subfield constituting one frame is not represented by a multiplier of 2, but is represented by each subfield. It is an object of the present invention to provide a method and apparatus for driving a PDP in which the luminance levels are continuous by comparing the actual luminance level with the reference level and adjusting the number of sustain pulses applied to the respective subfields by the difference.

1 is a view showing the discontinuity of the luminance level according to the prior art;

2 is a block diagram showing a configuration of the present invention;

3 is a diagram showing a subfield in which the number of sustain pulses is corrected according to the present invention;

4 shows the luminance level corrected by the present invention.

<Description of the reference numerals for the main parts of the drawings>

210: memory controller 220: main block of the present invention

221: subfield detector 223: comparator

225: count correction unit 227: sustain pulse correction unit

230: sustain driver 240: Y electrode driver

250: Z electrode driver 260: address electrode driver

270: PDP panel

The configuration of the luminance level correction device of a three-electrode surface discharge plasma display panel (hereinafter referred to as a three electrode surface discharge PDP) according to the present invention for solving the above object is

Memory means for storing image information to be displayed in each cell on the panel of a three-electrode surface discharge plasma display panel (hereinafter referred to as a three-electrode surface discharge PDP); Field detection means for determining, comparison means for receiving information on the subfield at the corresponding point of time from the field detection means, and comparing it with a reference subframe, and increasing the number of sustain pulses to be applied at the corresponding point according to the output of the comparator. Or a count up-down means for reducing, a sustain pulse correcting means for correcting the number of sustain pulses according to the output of the count-up down means, and a horizontal electrode (Y) of the PDP panel according to the corrected sustain pulses received from the sustain pulse correcting means. And Z electrode) sustain drive means for controlling the drive means, and a control signal from the sustain drive means. Receiving Y electrode driving means and Z electrode driving means for driving horizontal electrodes (Y, Z electrodes) of each cell on the PDP panel, and driving address electrodes of each cell on the PDP panel according to image information stored in the memory means. Characterized in that the address electrode driving means.

In the method of correcting the luminance level of the three-electrode surface discharge plasma display panel (hereinafter, referred to as a three-electrode surface discharge PDP) of the present invention configured as described above, one frame is divided into X subfields, and each of the subfields is 1 ~. 2 to express brightness in proportion to ^X-1 , and each cell is turned on in the corresponding subfield among the X subfields and emits light, and is turned off in the non-applicable subfield so as not to emit light. In this case, 2 ^X gray scales are expressed by a combination of ON subfields among the X subfields, and the luminance level to be expressed without actually multiplying the number of sustain pulses applied to the respective subframes by 2 is actually used. It is characterized in that the correction is made so as to reduce the error between the expressed luminance levels.

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

2 is a block diagram showing the structure of the present invention as described above.

As shown, a memory controller 210 for storing image information of each cell on the PDP panel, a field detector 221 for determining a subfield at a corresponding point in time from the image information of the memory controller 210, and the field. The comparator 223 which receives information on the subfield of the corresponding point of time from the detector 221 and compares it with the reference subfield SF4 or SF5, and the number of sustain pulses to be applied at the corresponding point of time from the output of the comparator 223. A count-up-down part 225 for calculating?, A sustain pulse correction part 227 for correcting the number of sustain pulses according to the output of the count-up-down part 225, and a correction received from the sustain pulse correction part 227; A sustain driver 230 for controlling the Y electrode driver 240 and the Z electrode driver 250 according to the sustain pulse, and a Y electrode driver 240 and a Z electrode driver receiving control signals from the sustain driver 230. 250 ), A cell receiving driving pulses from the address electrode driver 260 receiving image information from the memory controller 210, the Y electrode driver 240, the Z electrode driver 250, and the address electrode driver 260. Made of a PDP panel 270 having a matrix structure.

3 shows an example in which the number of sustain pulses in each subfield is corrected according to the present invention as described above.

In FIG. 3, eight subfields forming one frame (SF1, SF2, SF3, SF4, SF5, SF6, SF7, SF8) are shown. Each of the subfields includes an address and a sustain period.

The address period is the same for all subfields, and the number of sustain pulses applied for each sustain period of each subfield is adjusted as follows.

That is, SF1: SF2: SF3: SF4: SF5: SF6: SF7: SF8 = 1: 2: 7: 15: 33: 70: 146: 302 as indicated by numbers below each subfield.

The luminance level according to the sustain pulse corrected as above is shown in FIG.

Referring to FIG. 4, since the sustain pulse is applied with a multiplier of 2 per subframe in the prior art, the conventional luminance curve 420 having discontinuous points and the average value of the conventional luminance curve 420 are known. The average value 410 of the curve and the corrected luminance curve 430 according to the present invention are shown in which the discrete points of the conventional luminance curve are removed.

For reference, looking at the corrected luminance level at the point where the luminance difference is particularly severe in the prior art,

The luminance increases by 1 (cd / m ² ) at the point of change from the seventh level, the sum of SF1,2,3, to the eighth level, SF4,

The luminance increases by 1 (cd / m ² ) at the point that changes from the 15th level, the sum of SF1, 2, 3, 4 to the 16th level, SF5,

The luminance increases by 1.2 (cd / m ² ) at the point of change from the 31th level, which is the sum of SF1,2,3,4,5, to the 32th level of SF6,

Luminance increases by 1.4 (cd / m ² ) at the point of change from the 63rd level, the sum of SF1,2,3,4,5,6 to the 64th level, SF7,

At the point that changes from the level 127, which is the sum of SF1,2,3,4,5,6,7, to the level 128 of SF8, the luminance increases by 1 (cd / m ² ), so that the luminance level decreases at each discontinuous point. It can be seen that the conventional luminance curve was shown to be corrected to be continuous.

According to the present invention, by adjusting the number of sustain pulses applied to each subfield of one frame, correcting the luminance level actually expressed to be equal to the reference level, the problem of discontinuity of the luminance level is solved, and all the cells of the entire screen are the reference luminance. Since it is uniformly corrected according to the level, the image quality of the three-electrode surface discharge PDP is improved.

On the other hand, according to the present invention, the luminance level can be easily adjusted, such as increasing the overall luminance of the screen.

Claims (3)

Memory means for storing image information to be displayed in each cell on the panel of a three-electrode surface discharge plasma display panel (hereinafter referred to as a three-electrode surface discharge PDP); Field detection means for determining, comparison means for receiving information on the subfield at the corresponding point of time from the field detection means, and comparing it with a reference subframe, and increasing the number of sustain pulses to be applied at the corresponding point according to the output of the comparator. Or a count up-down means for reducing, a sustain pulse correcting means for correcting the number of sustain pulses according to the output of the count-up down means, and a horizontal electrode (Y) of the PDP panel according to the corrected sustain pulses received from the sustain pulse correcting means. And Z electrode) sustain drive means for controlling the drive means, and a control signal from the sustain drive means. Receiving Y electrode driving means and Z electrode driving means for driving horizontal electrodes (Y, Z electrodes) of each cell on the PDP panel, and driving address electrodes of each cell on the PDP panel according to image information stored in the memory means. A luminance level correction device for a three-electrode surface discharge PDP, comprising: address electrode driving means. In order to display the gray scale of an image on a three-electrode surface discharge plasma display panel (hereinafter referred to as a three-electrode surface discharge PDP), one frame is divided into X subfields, and each of the subfields is 1 to 2. A brightness proportional to ^X-1 is expressed, and each cell is turned on to emit light only in a corresponding subfield among the X subfields, and is not turned off to emit light in an unapplied subfield. In the brightness level correction method of a three-electrode surface discharge PDP for correcting the discontinuity of the brightness level that appears when expressing the 2 ^X gray scale by the combination of the ON sub-field of the X sub-field, A first step of determining, from the image data applied to each cell of the three-electrode surface discharge PDP, the subfield to be expressed at that time; A second step of determining the number of sustain pulses applied in the corresponding subfield according to the result of the first step; And a third step of applying the sustain pulse of the number determined in the second step to each horizontal electrode of the three-electrode surface discharge PDP. The method of claim 2, In order to implement 256 gray levels, one frame is divided into eight subfields, and each of the eight subfields includes SF1: SF2: SF3: SF4: SF5: SF6: SF7: SF8 = 1: 2: 7: 15: 33: 70: 146: 302 brightness pulses correction method for a three-electrode surface discharge PDP characterized by applying a sustain pulse.