KR20090077574A - Plasma display panel device - Google Patents

Abstract

A plasma display apparatus is provided to prevent the display distortion in the plasma display panel by varying gray levels about the selected block regions of most low luminance and different luminance. A plasma display apparatus has a plasma display panel. The plasma display panel has a display region(52). The display region displays an image. The display region is subdivided into a plurality of the block regions(52A, 52B). At least one of block regions has the gray level varied according to criteria.

Description

Plasma display panel device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device, and more particularly, to a plasma display device in which an imbalance in brightness and color temperature characteristics of a plasma display panel is improved.

In the play panel, the partition wall formed between the upper substrate and the lower substrate forms one unit cell, and in each cell, a main discharge such as neon (Ne), helium (He), or a mixture of neon and helium (Ne + He) It is filled with an inert gas containing gas and a small amount of xenon. 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.

Conventionally, in the plasma display device, a phenomenon in which the brightness and the color temperature characteristics of the displayed image are different according to the plasma display panel position occurs due to the characteristics of the plasma display panel and the discharge characteristics.

Recently, researches are being conducted on the plasma display device to ensure uniformity of luminance and color temperature characteristics of an image displayed on the plasma display panel.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma display apparatus which improves an imbalance in luminance and color temperature characteristics of a plasma display panel.

A plasma display device according to the present invention includes a plasma display panel including a display area in which an image is displayed, wherein the display area is divided into a plurality of block areas, and a gray level value of at least one block of the plurality of block areas. It characterized by varying according to a predetermined criterion.

The plasma display apparatus according to the present invention arbitrarily sets a display area in which an image is displayed to a plurality of block areas, and selects a block area having a different brightness from a block area having a lowest brightness among the plurality of block areas to have the same brightness. By varying the gray level values of at least one block area among the plurality of block areas according to a reference and subfield mapping, the luminance and color temperature characteristics of the display area are uniform throughout, so that the image is uniform on the display area. It is effective in preventing distortion.

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. The 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 plan view illustrating a plurality of block areas among display areas of a plasma display device according to a first exemplary embodiment of the present invention, and FIG. 5 is a functional block diagram illustrating a configuration of the plasma display device shown in FIG. 4.

The display area 52, which is an area where an image is displayed, is displayed on the plasma display panel 50.

Here, the display area 52 includes a first block area 52A positioned at the center portion and a second block area 52B surrounding the first block area 52A.

The luminance of the monochromatic image and the color temperature of the color image are measured in the first block area 52A and the second block area 52B.

Here, luminance and color temperature are substantially the same in at least one of the first and second block regions 52A and 52B.

That is, the luminance and color temperature of the input grayscale data measured in the first block area 52A and the second block area 52B are grasped, and among the first and second block areas 52A and 52B, the luminance and color temperature are the lowest. Find the first block area.

Here, in the remaining block areas except for the first block area among the first and second block areas 52A and 52B, the input gray level data is varied by varying the input gray level data so that the same luminance and color temperature as those of the first block area appear. Subfield mapping is performed on APL values corresponding to data to supply a sustain signal.

Accordingly, the first and second block regions 52A and 52B exhibit substantially uniform luminance and color temperature characteristics.

4 and 5, the plasma display apparatus includes an inverse gamma correction unit 100, an APL calculation unit 102 for each block region, a halftone unit 106, and a subfield mapping unit 108.

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

The APL calculator 102 for each block region measures the output gradation for the first block region 52A and the second block region 52B and the luminance for the output gradation, and then the luminance is displayed in the display region 52. The output gray levels of the block areas A1 to A32 included in the first and second block areas 52A and 52B are varied so as to appear uniformly on the image.

That is, the APL calculator 102 for each block area may have a block area different from the gray level of the first and second blocks A12 and A13 among the blocks A1 to A32 included in the first and second block areas 52A and 52B. Denotes the gray level of different R cells, G cells, and B cells.

For example, in the APL calculator 102 for each block area, an output gray level having the same gray level as the previous gray level is output to the first and second block areas 52A and 52B.

In this case, the APL calculation unit 102 for each block region has one of the first and second blocks A12 and A13 having the lowest luminance among the first and second block regions A12 and A13 and the remaining block region. Assumes the same brightness.

That is, it is assumed that the luminance of the first block region 52A among the first and second block regions 52A and 52B is lower than the luminance of the second block region 52B.

Here, when the first block 12 among the first and second blocks A12 and A13 has the lowest luminance, the APL calculator 102 for each block area may determine a gray level of the luminance of the first block 12 based on a predetermined reference value. In this way, the gray level is varied so that the luminance of the remaining blocks is lowered by the luminance of the first block 12.

In other words, the APL calculator 102 for each block area receives a sustain signal for '1023' having substantially the same gray level to the first and second block areas 52A and 52B, and thus discharges the first and second blocks. If the luminance of (A12, A13) is 160 cd / m 2 and 180 cd / m 2, respectively, and the luminance of the remaining blocks is measured at 200 cd / m 2, each of the respective blocks may appear to appear in the remaining blocks to be substantially equal to the luminance of the first block A 12. The gradation is varied.

Therefore, when the gray level of the first block A12 is '1023', the APL calculation unit 102 for each block area has 160 cd / m 2, so that the gray level of the second block A13 and the remaining blocks is 160 cd / m 2. To calculate.

That is, the APL calculator 102 for each block area calculates the gray level of the luminance of each of the blocks A1 to A32 according to a predetermined method, and when the gray level of the second block A13 is '1000', 160 cd / With the m 2, when the gray level of the remaining blocks is '950', 160 cd / m 2 varies the gray levels of the first and second block areas 52A and 52B.

Therefore, the APL calculator 102 for each block area may have different gray levels for each of the blocks A1 to A12, and calculate an APL value according to the calculated gray levels.

Accordingly, the APL calculation unit 102 for each block region maintains the uniformity of the luminance and color temperature for each of the blocks A1 to A32 even though the overall luminance and color temperature are lowered by varying the gray scale to the display region 52. There is an advantage.

The halftone unit 106 quantizes the input grayscale data of R (Red), G (Green), and B (Blue) output from the APL calculation unit 102 for each block region, and then diffuses an error component into adjacent cells. The brightness is finely adjusted according to the APL value, thereby improving gray scale expression.

The subfield mapping unit 108 adjusts the sustain signal corresponding to the APL value so that an image appears on the plasma display panel.

The plasma display apparatus of the present invention divides a display area into at least one block area, and based on input grayscale data of brightness and color temperature of each block, R cells of other blocks based on at least one of brightness or color temperature, Lowering the gray level of the G and B cells has the advantage that the luminance and color temperature appear uniformly.

While 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 plan view illustrating a plurality of block areas among display areas of a plasma display device according to a first embodiment of the present invention.

FIG. 5 is a functional block diagram showing the configuration of the plasma display device shown in FIG. 4.

Claims (5)

1. A plasma display apparatus comprising a plasma display panel including a display area in which an image is displayed. The display area is divided into a plurality of block areas, And a gray value of at least one block of the plurality of block areas is varied according to a predetermined reference. The method of claim 1, The plurality of block areas includes an R cell, a G cell, and a B cell. And a gradation value for the R cell, the G cell, and the B cell is varied to appear substantially the same as the predetermined reference. The method of claim 1, And when the gray value is higher than the predetermined reference, lowering the gray value to the predetermined reference. The method of claim 1, The predetermined criterion is the lowest luminance among respective luminances of the plurality of block regions, First and second regions showing different luminance among the plurality of block regions, And the gradation value is varied so that the same luminance is displayed according to the predetermined criterion. The method of claim 1, wherein the image, Plasma display device characterized in that the image of a monochrome pattern.

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