KR20090060588A - Plasma display panal device - Google Patents

Abstract

A plasma display panel device is provided to correct a white balance in relation to the number of sustain and APL(Average Picture Level) by using different characteristic curve to a low level gray scale and high level gray scale respectively. An APL(Average Picture Level) determination unit(102) determines APL value of R,G, and B to be suitable for a color temperature. An APL correction(104) corrects white balance to R,G, and B input data and the number of sustain according to the APL value, and it divides a level period determining R,G, and B input data, and the number of sustain with two. The APL correction corrects a low gray scale and a high gray scale with a different characteristic curve at each level section.

Description

Plasma display panal device

The present invention relates to a plasma display device, and more particularly, to a plasma display device for reducing color offset in a gray image.

In general, a plasma display panel is a partition wall formed between an upper substrate and a lower substrate to form one unit cell, and each cell includes neon (Ne), helium (He), or a mixture of neon and helium (Ne + He) and An inert gas containing the same main discharge gas and a small amount of xenon is filled. When discharged by a high frequency voltage, the inert gas generates vacuum ultraviolet rays and emits phosphors formed between the partition walls to realize an image. Such a plasma display panel has a spotlight as a next generation display device because a thin and light configuration is possible.

In the plasma display device, gray scales appear when the gray image is displayed on the plasma display panel.

Recently, a plasma display device is under study for a method of reducing color offset in a gray image.

Conventional plasma display devices do not adjust the white balance separately or adjust the white balance only by adjusting the APL gain value in order to reduce the color offset, but the white balance does not match at low gradation levels. There is a problem.

An object of the present invention is to provide a plasma display device for reducing the color offset phenomenon in a gray image.

In the plasma display device according to the present invention, R (Red), G (Green), and B (Blue) input data of an image signal are matched with color temperature according to a set target coordinate, and R (Red), G (Green), and B (Blue). An APL determination unit to determine respective APL (Averrage Picture Level) values for the < RTI ID = 0.0 > And an APL corrector configured to correct white balance with respect to the input data and the number of sustains of the R (Red), G (Green), and B (Blue) according to Average Picture Level (APL) values of the R, G, and B, respectively. Wherein the APL corrector divides the R (Red), G (Green), and B (Blue) input data and the level intervals for determining the number of sustains into at least two or more levels, and the low level gray level and the high level according to each level interval. It is characterized by correcting by varying the slope of the characteristic curve according to the gradation.

The plasma display apparatus of the present invention uses characteristic curves having different slopes according to low and high level gray scales, thereby correcting the white balance for the APL value and the number of sustains, thereby substantially reducing the color of the gray image in all the images to which the APL is applied. The effect is to remain the same.

Hereinafter, a plasma display device according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view illustrating a structure of a plasma display panel according to a first embodiment of the present invention.

Referring to FIG. 1, the plasma display panel 100 of the present invention includes the scan electrodes 11 and 12 and the sustain electrode 15 formed on the front panel 10, and the address electrodes formed on the back panel 20. (22).

The scan electrodes 11 and 12 and the sustain electrode 15 generally include transparent electrodes 11a, 12a and 15a formed of indium tin oxide (ITO) and bus electrodes 11b, 12b and 15b. The bus electrodes 11b, 12b, and 15b may be formed of a metal such as silver (Ag) or chromium (Cr) or a stack of chromium / copper / chromium (Cr / Cu / Cr) or chromium / aluminum / chromium (Cr / Al / It may be formed in a stacked form of Cr). The bus electrodes 11b, 12b and 15b are formed on the transparent electrodes 11a, 12a and 15a, and serve to reduce the voltage drop caused by the transparent electrodes 11a, 12a and 15a having high resistance.

Meanwhile, according to the first embodiment of the present invention, the scan electrodes 11 and 12 and the sustain electrode 15 have a structure in which transparent electrodes 11a, 12a and 15a and bus electrodes 11b, 12b and 15b are stacked. The bus electrodes 11b, 12b, and 15b may be various materials such as photosensitive silver in addition to the materials listed above.

Absorbs external light generated outside the upper substrate 10 between the scan electrodes 11 and 12 and the transparent electrodes 11a, 12a and 15a of the sustain electrode 15 and the bus electrodes 11b, 12b and 15b. Thus, black matrixes 11c, 12c, and 15c, which serve to reduce reflection and improve the purity and contrast of the upper substrate 10, are arranged.

The black matrix 11c, 12c, and 15c may be formed between the transparent electrodes 11a, 12a and 15a and the bus electrodes 11b, 12b and 15b according to the first embodiment of the present invention. Here, the black matrices 11c, 12c, and 15c may be simultaneously formed and physically connected in the formation process, and may not be simultaneously formed because they are not formed at the same time, and are integrally formed with only the black matrices 11c, 12c, and 15c. Can be.

Here, the bus poles 11b, 12b and 15b are stacked with the stacked black matrices 11c, 12c and 15c and the transparent electrodes 11a, 12a and 15a. In other words, the bus electrodes 11b, 12b, and 15b are stacked at a distance from one edge of the black matrices 11c, 12c, and 15c, and are stacked with the transparent electrodes 11a, 12a, and 15b by the predetermined distance.

Accordingly, the bus electrodes 11b, 12b, and 15b are formed integrally with each other by being separated by the predetermined distance from one edge of the black matrix 11c, 12c, and 15c. However, the bus electrodes 11b, 12b, and 15b may be formed as a separate type instead of an integral type. .

The upper dielectric layer 13 and the passivation layer 14 are stacked on the front panel 10 having the scan electrodes 11 and 12 and the sustain electrode 15 side by side. Charged particles generated by the discharge are accumulated in the upper dielectric layer 13, and the scan electrodes 11 and 12 and the sustain electrode 15 may be protected. The protective film 14 protects the upper dielectric layer 13 from sputtering of charged particles generated during gas discharge, and increases emission efficiency of secondary electrons. In addition, magnesium oxide (MgO) may be generally used for the protective film 14, and Si-MgO to which silicon (Si) is added may be used. Here, the content of silicon (Si) added to the protective film 14 may be 50PPM to 200PPM based on the weight percent (wt%).

On the other hand, the address electrode 22 is formed in the direction crossing the scan electrodes 11 and 12 and the sustain electrode 15. In addition, the lower dielectric layer 24 and the partition wall 21 are formed on the back panel 20 on which the address electrode 22 is formed.

In addition, the phosphor layer 23 is formed on the surfaces of the lower dielectric layer 24 and the partition wall 21. The partition wall 21 has a vertical partition wall 21a and a horizontal partition wall 21b formed in a closed shape, and physically distinguishes discharge cells, and prevents ultraviolet rays and visible light generated by the discharge from leaking into adjacent discharge cells.

In the first embodiment of the present invention, not only the structure of the partition wall 21 illustrated in FIG. 1, but also the structure of the partition wall 21 having various shapes may be possible. For example, a channel type having a channel that can be used as an exhaust passage in at least one of a differential partition structure, a vertical partition 21a, or a horizontal partition 21b having different heights of the vertical partition 21a and the horizontal partition 21b. The barrier rib structure having a groove formed in at least one of the barrier rib structure, the vertical barrier rib 21a or the horizontal barrier rib 21b may be possible.

Here, in the case of the differential partition wall structure, the height of the horizontal partition wall 21b is more preferable, and in the case of the channel partition wall structure or the groove partition wall structure, it is preferable that a channel is formed or the groove is formed in the horizontal partition wall 21b. something to do.

Meanwhile, in the first embodiment of the present invention, although each of the R, G, and B discharge cells is illustrated and described as being arranged on the same line, it may be arranged in other shapes. For example, a Delta type arrangement in which R, G, and B discharge cells are arranged in a triangular shape may be possible. In addition, the shape of the discharge cell may be not only rectangular but also various polygonal shapes such as pentagon and hexagon.

In addition, the phosphor layer 23 emits light by ultraviolet rays generated during gas discharge to generate visible light of any one of red (R), green (G), and blue (B). Here, an inert mixed gas such as He + Xe, Ne + Xe and He + Ne + Xe for discharging is injected into the discharge space provided between the front panel 10 and the rear panel 20 and the partition wall 21.

2 is an electrode layout diagram illustrating an electrode layout of a plasma display panel according to a first embodiment of the present invention.

Referring to FIG. 2, the plurality of discharge cells constituting the plasma display panel is preferably arranged in a matrix form as shown in FIG. 2. The plurality of discharge cells are provided at the intersections of the scan electrode lines Y1 to Ym, the sustain electrode lines Z1 to Zm, and the address electrode lines X1 to Xn, respectively. The scan electrode lines Y1 to Ym may be driven sequentially or simultaneously, and the sustain electrode lines Z1 to Zm may be driven simultaneously. The address electrode lines X1 to Xn may be driven by being divided into odd-numbered lines and even-numbered lines, or sequentially driven.

Since the electrode arrangement shown in FIG. 2 is only a first embodiment of the electrode arrangement of the plasma panel according to the present invention, the present invention is not limited to the electrode arrangement and driving method of the plasma display panel shown in FIG. 2. For example, a dual scan method in which two scan electrode lines among the scan electrode lines Y1 to Ym are simultaneously scanned is possible. In addition, the address electrode lines X1 to Xn may be driven by being divided up and down in the center portion of the panel.

FIG. 3 is a timing diagram illustrating a first embodiment of a method for time-division driving by dividing one frame into a plurality of subfields.

Referring to FIG. 3, a unit frame may be divided into a predetermined number, for example, eight subfields SF1,..., SF8 to realize time division gray scale display. Each subfield SF1, ... SF8 is divided into a reset section (not shown), an address section A1, ..., A8 and a sustain section S1, ..., S8.

Here, according to the first embodiment of the present invention, the reset period may be omitted in at least one of the plurality of subfields. For example, the reset period may exist only in the first subfield or may exist only in a subfield about halfway between the first subfield and all the subfields.

In each address section A1, ..., A8, a display data signal is applied to the address electrode X, and scan pulses corresponding to each scan electrode Y are sequentially applied.

In each of the sustain periods S1, ..., S8, a sustain pulse is alternately applied to the scan electrode Y and the sustain electrode Z to form wall charges in the address periods A1, ..., A8. It causes a sustain discharge in the discharge cell.

The luminance of the plasma display panel is proportional to the number of sustain discharge pulses in the sustain discharge periods S1, ..., S8 occupied in the unit frame. When one frame forming one image is represented by eight subfields and 256 gradations, each subfield in turn has different sustains at a ratio of 1, 2, 4, 8, 16, 32, 64, and 128. The number of pulses can be assigned. In order to obtain luminance of 133 gradations, cells may be sustained by addressing the cells during the subfield 1 section, the subfield 3 section, and the subfield 8 section.

The number of sustain discharges allocated to each subfield may be variably determined according to weights of the subfields according to the APC (Automatic Power Control) step. That is, in FIG. 3, a case in which one frame is divided into eight subfields has been described as an example. However, the present invention is not limited thereto, and the number of subfields forming one frame may be variously modified according to design specifications. . For example, a plasma display panel may be driven by dividing one frame into eight or more subfields, such as 12 or 16 subfields.

The number of sustain discharges allocated to each subfield can be variously modified in consideration of gamma characteristics and panel characteristics. For example, the gray level assigned to subfield 4 may be lowered from 8 to 6 and the gray level assigned to subfield 6 may be increased from 32 to 34.

4 is a functional block diagram showing a configuration of a plasma display device according to a first embodiment of the present invention, FIG. 5 is a graph showing the number of sustains according to the APL value according to FIG. 4, and FIG. Table showing input gray scales showing an embodiment.

Referring to FIG. 4, the plasma display apparatus includes an inverse gamma correction unit 100, an APL determination unit 102, an APL correction unit 104, a halftone unit 106, and a subfield mapping unit 108.

The inverse gamma correction unit 100 linearly converts the displayed luminance value by correcting the output gray value according to the gray value of the image signal through prestored gamma data.

The APL determiner 102 is configured to match R (Red), G (Green) and R (Red), G (Green), Determine each APL (Average Picture Level) value for one frame for B (Blue).

In addition, the APL corrector 104 is configured to white the input data and the number of sustains of the R (Red), G (Green), and B (Blue) according to the AVER (Averrage Picture Level) values of the R, G, and B, respectively. Correct the balance.

That is, the APL corrector 104 divides the R (Red), G (Green), and B (Blue) input data and the level intervals for determining the number of sustains into at least two or more, and low-level gradation according to each level interval. And correcting by varying the slope of the characteristic curve according to the high level gradation.

The halftone unit 106 quantizes the input data of R (Red), G (Green), and B (Blue) output from the APL correcting unit 104, and then diffuses error components into adjacent cells, according to the APL value. Finely adjust the luminance value to improve the gradation power.

The APL mapping unit 108 adjusts the number of sustains according to the APL value so that an image is displayed on the plasma display panel.

Referring to FIG. 5, the APL corrector 104 virtually divides a plurality of blocks on a plasma display panel (not shown), and lowers a high level of luminance to a lowest level of luminance among the plurality of blocks. .

That is, FIG. 5 shows at least two or more levels with respect to the APL value, and shows a characteristic curve for adjusting the number of sustains according to the at least two or more levels.

Accordingly, the APL corrector 104 determines the R (Red), G (Green), and B (Blue) input data and the number of sustains, so that light and dark portions of the gray image do not occur. The APL value corresponding to the high level gradation of the bright portion is lowered to the low level gradation of the dark portion so that the color of the hue remains substantially the same.

Referring to FIG. 6, the sustain number is indicated according to the APL value of the characteristic curve shown in FIG. 5.

It is formed in at least two sections according to the APL value, it can be seen that the sustain number is supplied to the R, G, B cells differently in each section.

Referring to FIG. 6, one APL section is divided into five level sections to represent an input gray level applied to the R, G, and B discharge cells.

 In the APL section having a value of 896, referring to the 'ㅁ' block, it can be seen that the input gray scale applied to the R, G, and B discharge cells in the D and E sections, that is, the sustain number is different.

That is, the APL correction unit 104 of the characteristic curve representing the input data of the R (Red), G (Green) and B (Blue) and the gain of the R (Red), G (Green) and B (Blue) By changing the slope, it is to prevent the color offset phenomenon and to make the color of the monochrome pattern image appear substantially the same.

Although the above has been described in detail with respect to preferred embodiments of the present invention, those skilled in the art to which the present invention pertains, the present invention without departing from the spirit and scope of the invention defined in the appended claims It will be appreciated that various modifications or changes can be made. Accordingly, modifications to future embodiments of the present invention will not depart from the technology of the present invention.

1 is a perspective view illustrating a structure of a plasma display panel according to a first embodiment of the present invention.

2 is an electrode layout diagram illustrating an electrode layout of a plasma display panel according to a first embodiment of the present invention.

FIG. 3 is a timing diagram illustrating a first embodiment of a method for time-division driving by dividing one frame into a plurality of subfields.

4 is a functional block diagram showing a configuration of a plasma display device according to a first embodiment of the present invention.

FIG. 5 is a graph showing the number of sustains according to the APL value shown in FIG. 4.

FIG. 6 is a table illustrating input gray scales illustrating the first exemplary embodiment of FIG. 4.

Claims (3)

Average APL (Averrage Picture Level) for R (Red), G (Green), and B (Blue) to match the color temperature according to the set target coordinates according to the R (Red), G (Green) and B (Blue) input data of the image. APL determining unit for determining a value and white for input data and sustain number of R (Red), G (Green) and B (Blue) according to APL (Averrage Picture Level) value of each of R, G and B Including an APL correction unit for correcting the balance, The APL corrector, The R (Red), G (Green) and B (Blue) input data and the level intervals for determining the number of sustains are divided into at least two or more, and the slope of the characteristic curve according to the low level gray level and the high level gray level according to each level interval Plasma display device for correcting by different. The method of claim 1, wherein the APL corrector, And a color tone corresponding to the low level gray level and the high level gray level substantially equally corrected. The method of claim 1, wherein the image is Plasma display device characterized in that the monochrome pattern image.

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