KR20080001179A - Method and apparatus for compensating data of liquid crystal display - Google Patents

Abstract

A method and an apparatus for compensating data in a flat panel display are provided to solve non-uniformity of the flat panel display, caused during a process due to overlapping of lens and lens aberration, by adjusting a digital video data value, thereby making brightness of a display surface uniform even in a flat panel display where brightness of display surfaces are partially different. Brightness is measured by supplying data of the same gradation to the whole display surface of a flat panel display(S1). It is determined whether brightness of first and second display surfaces are differently measured and whether an overlapped surface generated according as the first and second display surfaces are overlapped and having brightness different from the brightness of the first and second display surfaces is present in the flat display panel. By comparing brightness of a non-overlapped surface of the first display surface with brightness of the non-overlapped surface of the second display surface, one display surface of the first and second display surfaces is selected and a first compensation value for the selected display surface is determined(S2). The overlapped surface is virtually divided into plural sections. Based on the above comparison result, second compensation values gradually changing between the sections are determined(S3). Digital video data to be displayed on the selected display surface is compensated by the first compensation value, and data to be displayed on the overlapped surface is compensated by the second compensation values(S4).

Description

Method and device for compensating data of flat panel display device {Method and Apparatus for Compensating Data of Liquid Crystal Display}

1 is a view schematically showing a lens arrangement of the exposure equipment.

FIG. 2 is a photograph showing the degradation of display quality observed by panel defects caused by the exposure equipment shown in FIG.

3 is a diagram schematically showing a luminance difference as shown in FIG. 2.

4 is a flowchart illustrating a data compensation method step by step according to an embodiment of the present invention.

5 is a view for explaining an example of sections virtually divided in an overlapping surface.

FIG. 6 is a photograph showing a boundary luminance difference observed in a display image when a compensation value of 0.5 gray scale or more is applied in adjacent sections in an overlapping surface. FIG.

7 is a photograph showing a displayed image when a compensation value of less than 0.5 gray scale is applied in adjacent sections in an overlapping surface.

8 is a graph showing gamma characteristics of data.

9 is a view for explaining that the compensation value is different according to the position.

FIG. 10 is a diagram illustrating measured luminance, a compensation value, and a compensation result of the first panel defect surface MR1, the first and second overlapping surfaces GA1 and GA2 illustrated in FIG. 5.

FIG. 11 is a diagram illustrating measured luminance, a compensation value, and a compensation result of the second panel defect surface MR2, the third and fourth overlapping surfaces GA3 and GA4 illustrated in FIG. 5.

FIG. 12 is a diagram illustrating measured luminance, a compensation value, and a compensation result of the second panel defect surface MR2, the fifth and sixth overlapping surfaces GA5 and GA6 illustrated in FIG. 5.

13 is a view showing an example of a dither pattern applicable in the present invention.

14 is a block diagram illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 15 is a block diagram illustrating the compensation circuit shown in FIG. 14 in detail. FIG.

<Description of Major Symbols in Drawing>

161: data driving circuit 162: gate driving circuit

163: LCD panel 164: timing controller

165: compensation circuit 171: FRC control unit,

172: EEPROM 173: register

174 interface circuit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display device. In particular, the luminance of a display image is uniformly compensated for by the data to be displayed on the panel defect surface of the flat panel display panel caused by the overlap between a plurality of lenses installed in the exposure apparatus and the lens aberration. The present invention relates to a data compensation method and apparatus for a flat panel display device.

The flat panel display device includes a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP) and an organic light emitting diode display (OLED). OLED), and most of them are commercially available and commercially available.

Liquid crystal display devices can meet the trend of light and short and short of electronic products and mass production is improving, and are rapidly replacing cathode ray tubes in many applications.

In particular, an active matrix type liquid crystal display device that drives a liquid crystal cell using a thin film transistor (hereinafter referred to as "TFT") has the advantages of excellent image quality and low power consumption, and secures the latest mass production technology. As a result of research and development, it is rapidly developing into larger size and higher resolution.

The manufacturing process of the liquid crystal display device is to produce a TFT array substrate by a semiconductor process including a photolithography process. The photolithography process will include a series of exposure, development, and etching processes.

Recently, an exposure apparatus used in a process of simultaneously forming a plurality of pixel arrays PA1 to PA16 on a single mother substrate as shown in FIG. 1 includes a plurality of lenses 10 arranged in two rows. The lenses 10 include a multi-lens array that overlaps a predetermined width GW. Each of the pixel arrays PA1 to PA16 has a plurality of data lines and a plurality of gate lines orthogonal to each other, a TFT formed at an intersection thereof, and pixel electrodes are arranged in a matrix form. In addition, column spacers may be formed in each of the pixel arrays PA1 to PA16 to maintain a cell gap. These pixel arrays PA1 to PA16 are separated by a scribing process. In FIG. 1, arrows and numbers indicate the scanning direction and the scanning order of the lenses 10.

Each of the lenses 10 of the exposure apparatus has an aberration, and the aberration varies from lens to lens. For this reason, the light receiving amount and the light distribution of the photoresist applied on the mother substrate 12 are different for each lens position and overlapping position. Due to the difference in the exposure amount of the photoresist that appears differently at the position of each of the lenses 10 and the overlapping (GW) position between the lenses 10, the photoresist pattern after the developing process is changed to the position of each of the lenses 10 and the lenses ( 10) will be different at the overlap position between them. As a result, the overlapping area between the gates and the drains of the TFTs is partially different in the display surfaces of the pixel arrays PA1 through PA16 so that the pixel voltages vary according to the display surface, and columns in the pixel arrays PA1 through PA16 are different. The height of the spacer is different depending on the display surface and the cell gap is partially different.

FIG. 2 shows luminance smears of a display image in a liquid crystal display panel manufactured using the exposure apparatus shown in FIG. 1. When the test image of the same gradation is displayed on the liquid crystal display panel manufactured by using the exposure apparatus as shown in FIG. 1 as shown in the dotted line of FIG. 2, a portion where the boundary between them is not clear but appears darker than other portions may appear on the display image. do. On the other hand, when the light sensitivity of the photoresist is changed or the arrangement of the lenses 10 in FIG. 1 is adjusted, the area or position of the dark-looking part in FIG. 2 is different. The luminance distortion of the display image caused by the multi-lens type exposure apparatus as shown in FIG. 1 cannot be solved only by an improvement in the manufacturing process or a repair process.

Accordingly, an object of the present invention is to solve the problems caused by the prior art, and to compensate for the data to be displayed on the panel defect surface of the flat panel display panel caused by the overlap of the plurality of lenses installed in the exposure apparatus and the aberration of the lens. The present invention provides a method and apparatus for compensating data for a flat panel display device so as to make the luminance of a display image uniform.

In order to achieve the above object, a data compensation method of a flat panel display device according to an embodiment of the present invention comprises the steps of supplying data of the same gray level to the entire display surface of the flat panel display panel to measure the brightness; The luminance of the first display surface and the second display surface is measured differently in the flat panel display panel, and the first and second display surfaces are superposed therebetween so that the luminance is different from that of the first and second display surfaces. Determining whether a face exists; By comparing the difference between the non-overlapping surface luminance of the first display surface and the non-overlapping surface luminance of the second display surface, one of the first display surface and the second display surface is selected, and Determining a first compensation value; A second virtually dividing the overlapping surface into a plurality of sections and gradually changing between the sections based on a comparison result of the non-overlapping brightness of the first display surface and the non-overlapping brightness of the second display surface; Determining compensation values; And adjusting digital video data to be displayed on the selected display surface with the first compensation value, and adjusting data to be displayed on the overlapping surface with the second compensation values.

The second compensation values determined corresponding to each of the adjacent sections in the overlapping surface have a difference of less than 0.5 gray scales.

The selected display surface is a display surface having lower brightness among the first display surface and the second display surface.

The overlapping surface may include a first overlapping surface of which luminance is gradually lowered from one side to the other side in the measuring of the luminance; In the step of measuring the brightness includes a second overlapping surface that appears to gradually increase in brightness from one side to the other side.

Each of the first and second overlapping planes is virtually divided into the plurality of sections, and the second compensation values are determined to be 1: 1 corresponding values in each of the sections, and gradually differ from one side to the other side. Changes to.

The second compensation values for the first overlapping surface include constant values that gradually increase from one side to the other side; The second compensation values for the second overlapping surface include constant values that gradually decrease from one side to the other side.

In accordance with another aspect of the present invention, a data compensating device includes a flat panel display panel; As a result of measuring the luminance by supplying the same gray scale data to the entire display surface of the flat panel display panel, the display panel may be configured to include any one of the first and second display surfaces of which the luminance is measured differently on the flat panel display panel. A first compensation value, a second compensation value for the overlapping surface where the first and second display surfaces overlap and appear to be different from the luminance of the first and second display surfaces, and position information of the selected display surface and the overlapping surface; A memory for storing the; Receiving digital video data and a timing signal and detecting digital video data to be displayed on the selected display surface and the overlapping surface as a result of the comparison between the timing signal and the position information, and displaying the digital video data to be displayed on the selected display surface. A data compensator for adjusting data to be displayed on the overlapping surface to the second compensation values while adjusting to a compensation value; And a driving unit which receives the digital video data adjusted by the data compensator and drives the flat panel display panel.

The flat panel display panel includes any one of a liquid crystal display, a field emission display, a plasma display panel, and an organic light emitting diode display.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 3 to 15, focusing on a liquid crystal display device.

An example of panel defects caused by overlap between lenses and aberration of lenses is shown in FIG. 3. When displaying the test image by supplying the same gray scale test data to one screen of the sample, in FIG. 3, 'RA1' and 'RA2' are reference planes for determining compensation value without applying compensation value, and 'MR1' 'And' MR2 'are panel-defect surfaces in which a luminance difference appears from the reference planes RA1 and RA2. The panel defect planes MR1 and MR2 and the reference planes RA1 and RA2 overlap with each other to some extent so that their boundaries do not appear in the form of lines but in the form of planes in which the luminance gradually increases or decreases. That is, the brightness of the overlapping surface of the first panel defect surface MR1 and the first reference surface RA1 gradually increases toward the right side as shown by the arrow direction, and overlaps the first reference surface RA1 and the second panel defect surface MR2. The surface gradually decreases in brightness toward the right side. In addition, the brightness of the overlapping surface of the second panel defect surface MR2 and the second reference surface RA2 gradually increases toward the right side.

If the lens arrangement of the exposure apparatus is adjusted or a photoresist of different light sensitivity is used, the area and the position of the panel defect surfaces MR1 and MR2 and the reference surfaces RA1 and RA2 are different.

Meanwhile, if the compensation values to be applied to the reference planes RA1 and RA2 are determined based on the panel defect surfaces MR1 and MR2, the data to be displayed on the reference planes RA1 and RA2 is subtracted by the compensation values.

Hereinafter, the compensation values to be applied to the panel defect surfaces MR1 and MR2 and the overlapping surfaces GA1 to GA6 will be described. The compensation values applied to the panel defect surfaces MR1 and MR2 and the overlapping surfaces GA1 to GA6 are added to the data to be displayed on the panel defect surfaces MR1 and MR2 and the overlapping surfaces GA1 to GA6.

4 shows step by step a data compensation method according to an embodiment of the present invention.

Referring to FIG. 4, in the data compensation method according to an exemplary embodiment of the present invention, luminance is measured by supplying test data having the same gray level to a sample flat panel display panel to pixels of the entire display surface, and measuring the luminance as a result of the luminance measurement. The luminances of the non-overlapping surfaces of MR1 and MR2 and the non-overlapping surfaces of the reference surfaces RA1 and RA2 are determined. (S1) These measurements are performed on all gray scales that can be expressed on the flat panel display panel while changing the gray scale value of the test data. It is carried out repeatedly.

As a result of the luminance measurement, the present invention is characterized in that the luminance of the portion where the luminance is measured equally on the non-overlapping surfaces of the panel defect surfaces MR1 and MR2 and the luminance on the non-overlapping surfaces of the reference surfaces RA1 and RA2 are measured equally. The luminance of the portions are compared (S2). Here, the portions in which the luminance appears the same on the panel defect surfaces MR1 and MR2 are measured at the lowest luminance as the center portions not overlapping with the reference surfaces RA1 and RA2. The portion where the luminance appears equal in the reference planes RA1 and RA2 is measured at the highest luminance in the panel defect surfaces MR1 and MR2.

Subsequently to step S2, the data compensation method according to the embodiment of the present invention determines the compensation value. (S3) The compensation values are not applied to the reference planes RA1 and RA2, and the panel defect planes MR1 and MR2 are overlapped with each other. Applies to

The compensation value applied to the non-overlapping surface measured at the lowest luminance at the panel defect surfaces MR1 and MR2 is determined as the highest constant value. In the panel defect surfaces MR1 and MR2, the compensation values of the non-overlapping surfaces are determined as integer values, integer values + decimal values, and depend on the position and the gray value of the digital video data and are added to the digital video data.

The compensation values of the overlapping planes depend on the position and the gradation value, and are determined by a decimal value less than integer + 1 gradation. In the compensation value of the overlapping surface, a fractional value less than one gradation is represented by a frame rate control (hereinafter referred to as "FRC") using a dither pattern. Detailed description of the fine gray level compensation using the FRC will be described later.

The compensation value applied to the overlapping surface should be determined to be partially different because the luminance of the overlapping surface shows a gradual difference. To this end, in the data compensation method according to an embodiment of the present invention, the overlapping surface is virtually divided by a value obtained by converting the size of the overlapping surface into a pixel size and dividing the number of pixels corresponding to the overlapping surface by an integer as a result of the conversion. For each of these, the compensation values corresponding to 1: 1 are determined. These compensation values change gradually from one side to the other. In other words, in the overlapping surface, the compensation value is determined as a constant value that gradually decreases or increases based on the compensation value applied to the non-overlapping portions of the panel defect surfaces MR1 and MR2.

The compensation values to be applied to the panel defect surfaces MR1 and MR2 and the overlapping surface are composed of a look-up table together with the position information of the pixels to which the compensation values are applied, respectively. It is stored in Electrically Erasable Programmable Read Only Memory (EDD) or Extended Display Identification Data ROM (EDID ROM). Such a memory is a data compensation memory and is connected between the data input circuit and the data driving circuit in a flat panel display device with an adder for adding compensation values to the digital video data.

Subsequently to step S3, the data compensation method according to an embodiment of the present invention adds the compensation values determined in step S2 to the digital video data to be displayed on the panel defect planes MR1 and MR2 to compensate for the data.

FIG. 5 illustrates an example in which overlapping surfaces GA1 to GA6 are converted into pixel sizes, and as a result, a 64 pixel overlapping surface GA1 to GA6 is divided by 8, and the overlapping surface is virtually divided into eight sections. Shows. Here, each of the sections of the overlapping surfaces GA1 to GA6 is defined as having a size including eight pixels continuous in the horizontal direction. Compensation values are applied to these intervals as constant values that gradually increase or decrease. Three sections (GA1, GA4, GA5) of the six sections of the overlapping surfaces GA1 to GA6 belong to the panel defect surfaces MR1 and MR2, and the remaining three sections GA2, GA3, and GA6 are reference planes RA1, RA2). On the other hand, the compensation values applied to the panel defect surfaces MR1 and MR2 that do not overlap with the reference planes MR1 and MR2 are the same in the entire surface of the non-overlapping surfaces of the panel defect surfaces MR1 and MR2 when the same gray level is applied.

In the overlapping plane, the compensation value applied to the adjacent sections should be less than 0.5 gradations between them. Accordingly, the difference in compensation values allowed between adjacent sections of the overlapping surface is 1/8 (= 0.125) gradation, 2/8 (= 0.250) gradation, 3/8 (= 0.375) gradation, and the like.

FIG. 6 is a photograph photographing an actual display image by adding compensation values of a 0.5 gray level difference to digital data to be displayed in adjacent sections of an overlapping surface. As can be seen in FIG. 6, when even more than 0.5 compensation values are applied to adjacent sections in the overlapping plane, the luminance difference is visually observed at the boundary between adjacent sections. In contrast, when compensation values of less than 0.5 series are applied to adjacent sections in the overlapping surface, the luminance difference is not felt in the adjacent sections as shown in FIG. 7.

As described above, the compensation values applied to the overlapping surface should be optimized according to the display position and gray value of the digital video data in consideration of the gamma compensation characteristics of the data as shown in FIG. 8. For example, assuming that digital video data belonging to a specific gradation section in FIG. 8 is displayed at three pixels at different positions in the first overlapping surface GA1 as shown in FIG. 9, a compensation value is applied at each position. Since the luminance in the undisplayed image is different, the compensation value of the digital video data to be displayed on the pixel at the first position P1 should be determined to be a value corresponding to the 27/8 (= 3.125) gray scale, and the second position P2. The compensation value of the digital video data to be displayed on the pixel of ()) should be determined to a value corresponding to 16/8 (= 2.000) gray scale. The compensation value of the digital video data to be displayed on the pixel at the third position P3 should be a value corresponding to 12/8 (1.50) gray scale.

In addition, even when data to be displayed in the pixel of the same position, for example, the second position P2, when the gray value of the digital video data belongs to different gray periods in consideration of the gamma characteristic of each gray level, as shown in FIG. Compensation values must be optimized differently.

8 divides the gradation interval into four, but can be divided more finely, and can also be divided into fewer intervals. 10 to 12 and Tables 1 to 3 will be described in detail.

10 and Table 1 illustrate the non-overlapping surface of the first panel defect surface MR1 and the respective sections of the first and second overlapping surfaces GA1 and GA2 in the data compensation method according to the embodiment of the present invention. Shows the compensation value applied to (MR1, GA1, GA2).

a b c d e f g h i 0 ~ 60 gradation 1.125 1.000 0.875 0.750 0.625 0.500 0.375 0.250 0.125 60 to 120 gradations 2.250 2.000 1.750 1.500 1.250 1.000 0.750 0.500 0.250 More than 120 gradations 3.125 3.000 2.625 2.250 1.875 1.500 1.125 0.750 0.375

Referring to FIG. 10 and Table 1, the data compensation method according to an exemplary embodiment of the present invention includes a low gray scale range of 0 to 60 gray scales, a medium gray scale range of 61 to 120 gray scales, and a high gray scale including 121 or more gray scales. In each of the ranges, the luminance measured on the non-overlapping surface of the first reference plane MR1 and the non-overlapping surface of the first panel defect surface MR1 are compared. In addition, the present invention determines the compensation value to be applied to the entire surface of the non-overlapping surface of the first panel defect surface MR1 as the same constant value based on the luminance difference determined as a result of the luminance comparison, and also determines the first and second overlapping surfaces ( GA1, GA2) are determined as constant values that vary gradually.

Low gradation  Coverage of scope

The difference between the luminance of the low gradation range measured on the non-overlapping surface of the first panel defect surface MR1 and the luminance of the low gradation range measured on the non-overlapping surface of the first reference surface MR1 is approximately a gray scale value of '1.125'. Corresponds to On the non-overlapping front surface a of the first panel-defect surface MR1 such that the non-overlapping surface luminance of the first panel defect surface MR1 and the non-overlapping surface luminance of the first reference surface MR1 are the same in the low gradation range. Decide the compensation value of the low gradation range to be applied as '1.125'.

The luminance of the first and second overlapping surfaces GA1 and GA2 to which the compensation value is not applied gradually increases toward the right side. Accordingly, among the four sections b, c, d, and e that are virtually divided in the first overlapping surface GA1, the low gray range compensation value of the b section is '1.000' and the low gray range compensation value of the c section. May be determined as '0.875', the low gray range compensation value in the d section is '0.750', and the low gray range compensation value in the e section is '0.625', respectively. The low gradation range compensation values lowering toward the right side are added to the low gradation range digital video data to be displayed in the respective sections of the first overlap plane GA1. Also, among the four sections f, g, h, and i that are virtually divided on the second overlapping surface GA2, the low gray range compensation value of the f section is '0.500' and the low gray range compensation value of the g section. May be determined as '0.375', the low gray range compensation value in the h section is '0.250', and the low gray range compensation value in the i section is '0.125', respectively. The lowering compensation values are added to the low gray scale digital video data to be displayed in the sections of the second overlapping surface GA2.

Halftone  Coverage of scope

When no compensation value is applied, the luminance of the halftone range measured at the non-overlapping plane of the first panel defect surface MR1 and the luminance of the halftone range measured at the non-overlapping plane of the first reference plane MR1 is not applied. The difference corresponds to a gray scale value of approximately '2.250'. On the non-overlapping front surface a of the first panel-defect surface MR1 so that the non-overlapping surface luminance of the first panel defect surface MR1 and the non-overlapping surface luminance of the first reference surface MR1 are the same in the halftone range. The compensation value of the low gradation range to be applied is determined as '2.250'.

In the first overlapping surface GA1, the halftone compensation value of section b is '2.000', the halftone compensation value of section c is '1.750', the halftone compensation value of section d is '1.500', and the second section The halftone compensation value of may be determined as '1.250', respectively. The lower halftone compensation values that are lowered toward the right side are added to the digital video data of the halftone range to be displayed in the respective sections of the first overlap plane GA1. Further, in the second overlapping surface GA2, the mid-gradation range compensation value of the f section is '1.000', the mid-gradation range compensation value of the g section is '0.750', the half-gradation range compensation value of the h section is '0.500', The halftone compensation value of interval i may be determined as '0.250', respectively. The lowering compensation values are added to the digital video data of the halftone range to be displayed in the respective sections of the second overlapping surface GA2.

High gradation  Coverage of scope

In the state where the compensation value is not applied, the luminance of the high gradation range measured on the non-overlapping surface of the first panel defect surface MR1 and the luminance of the high gradation range measured on the non-overlapping surface of the first reference surface MR1 is not applied. The difference corresponds to a gray scale value of approximately '3.125'. On the non-overlapping front surface a of the first panel-defect surface MR1 such that the non-overlapping surface luminance of the first panel defect surface MR1 and the non-overlapping surface luminance of the first reference surface MR1 are the same within a high gradation range. Determine the compensation value of the high gradation range to be applied as '3.125'.

In the first overlapping surface GA1, the high gradation range compensation value of section b is '3.000', the high gradation range compensation value of section c is '2.625', the high gradation range compensation value of section d is '2.250', and the e section The high gray scale compensation value of can be determined as '1.875', respectively. The lowering of the high gradation range compensation values toward the right side is added to the digital video data of the high gradation range to be displayed in the respective sections of the first overlapping surface GA1. Further, in the second overlapping surface GA2, the high gray scale compensation value of the f section is '1.500', the high gray scale compensation value of the g section is '1.125', the high gray scale compensation value of the h section is '0.750', The high gradation range compensation value of the i section may be determined as '0.375', respectively. The lowering compensation values are added to the digital video data of the high gradation range to be displayed in the sections of the second overlapping surface GA2.

As a result of the application of the compensation value, the compensation luminance of the first panel defect surface MR1, the first and second overlapping surfaces GA1, GA2 is substantially equal to the non-overlapping surface luminance of the first reference surface MR1 in the entire gray scale range that can be expressed. Will be the same.

11 and Table 2 illustrate the non-overlapping planes of the second panel defect plane MR2 and the respective sections of the third and fourth overlapping planes GA3 and GA4 in the data compensation method according to the embodiment of the present invention. Shows the compensation value applied to (MR2, GA3, GA4).

a b c d e f g h i 0 ~ 60 gradation 1.125 1.000 0.875 0.750 0.625 0.500 0.375 0.250 0.125 60 to 120 gradations 2.250 2.000 1.750 1.500 1.250 1.000 0.750 0.500 0.250 More than 120 gradations 3.125 3.000 2.625 2.250 1.875 1.500 1.125 0.750 0.375

11 and 2, in the data compensation method according to an exemplary embodiment of the present invention, when the compensation value is not applied, the non-overlapping surface of the first reference plane MR1 in each of the low gray scale range, the mid gray scale range, and the high gray scale range, respectively. The luminance measured at and the luminance measured at the non-overlapping surface of the second panel defect surface MR2 are compared. According to the present invention, the compensation value to be applied to the entire surface of the non-overlapping surface of the second panel defect surface MR2 is determined to be the same constant value based on the luminance difference determined as a result of the luminance comparison, and the third and fourth overlapping surfaces ( GA3, GA2) are determined as constant values that vary gradually.

Low gradation  Coverage of scope

The difference between the luminance of the low gray scale range measured at the non-overlapping surface of the second panel defect surface MR2 and the luminance of the low gray scale range measured at the non-overlapping surface of the first reference surface MR1 is approximately '1.125'. Corresponds to On the non-overlapping front surface a of the second panel defect surface MR2 such that the non-overlapping surface luminance of the second panel defect surface MR2 and the non-overlapping surface luminance of the first reference surface MR1 are the same in the low gradation range. Decide the compensation value of the low gradation range to be applied as '1.125'.

The luminance of the third and fourth overlapping surfaces GA3 and GA4 to which the compensation value is not applied gradually decreases toward the right side. Accordingly, in the fourth overlapping surface GA4, the low gray range compensation value in the b section is '1.000', the low gray range compensation value in the c section is '0.875', and the low gray range compensation value in the d section is '0.750', e The low gray scale compensation value of the section may be determined as '0.625', respectively. The low gradation range compensation values that increase toward the right side are added to the low gradation range digital video data to be displayed in each section of the fourth overlapping surface GA4. In the third overlapping surface GA3, the low gray range compensation value of the f interval is '0.500', the low gray range compensation value of the g interval is '0.375', the low gray range compensation value of the h interval is '0.250', and The low gray scale compensation value may be determined as '0.125', respectively. The compensation values that increase toward the right side are added to the digital video data of the low gradation range to be displayed in the sections of the third overlapping surface GA3.

Halftone  Coverage of scope

In the state where the compensation value is not applied, the luminance of the halftone range measured at the non-overlapping plane of the second panel defect surface MR2 and the luminance of the halftone range measured at the non-overlapping plane of the first reference plane MR1 are measured. The difference corresponds to a gray scale value of approximately '2.250'. On the non-overlapping front surface a of the second panel-defect surface MR2 such that the non-overlapping surface luminance of the second panel defect surface MR2 and the non-overlapping surface luminance of the first reference surface MR1 are the same in the halftone range. The compensation value of the low gradation range to be applied is determined as '2.250'.

In the fourth overlapping surface GA4, the halftone compensation value of section b is '2.000', the halftone compensation value of section c is '1.750', the halftone compensation value of section d is '1.500', and the second section The halftone compensation value of may be determined as '1.250', respectively. The halftone range compensation values that increase toward the right side are added to the digital video data of the halftone range to be displayed in the respective sections of the fourth overlapping surface GA4. In the third overlapping surface GA3, the mid-range compensation value of section f is '1.000', the half-tone compensation value of section g is '0.750', the half-tone compensation value of section h is '0.500', and i section The halftone compensation value of may be determined as '0.250', respectively. The compensation values that increase toward the right side are added to the digital video data of the halftone range to be displayed in the respective sections of the third overlapping surface GA3.

High gradation  Coverage of scope

In the state where the compensation value is not applied, the luminance of the high gradation range measured on the non-overlapping plane of the second panel defect surface MR2 and the luminance of the high gradation range measured on the non-overlapping plane of the first reference plane MR1 is not applied. The difference corresponds to a gradation value of approximately '3.125'. On the non-overlapping front surface a of the second panel-defect surface MR2 such that the non-overlapping surface luminance of the second panel defect surface MR2 and the non-overlapping surface luminance of the first reference surface MR1 are the same within a high gradation range. Determine the compensation value of the high gradation range to be applied as '3.125'.

In the fourth overlapping surface GA4, the mid-gradation range compensation value of section b is '3.000', the high-gradation range compensation value of section c is '2.625', the high-gradation range compensation value of section d is '2.250', and the section e The high gray scale compensation value of can be determined as '1.875', respectively. The higher gradation range compensation values that increase toward the right side are added to the digital gradation data of the high gradation range to be displayed in each section of the fourth overlapping surface GA4. In the third overlapping surface GA3, the high gradation range compensation value of the f section is '1.500', the high gradation range compensation value of the g section is '1.125', the high gradation range compensation value of the h section is '0.750', and the i section The high gray scale compensation value of may be determined as '0.375', respectively. The compensation values that increase toward the right side are added to the digital video data of the high gradation range to be displayed in the sections of the third overlapping surface GA3.

As a result of the application of the compensation value, the compensation luminance of the second panel defect surface MR2, the third and fourth overlapping surfaces GA3 and GA4 is substantially equal to the non-overlapping surface luminance of the first reference surface MR1 in the entire gray scale range that can be expressed. Will be the same.

12 and Table 3 show the non-overlapping surfaces of the second panel defect surface MR2 and the respective sections of the fifth and sixth overlapping surfaces GA5 and GA6 in the data compensation method according to the exemplary embodiment of the present invention. Shows the compensation value applied to (MR2, GA5, GA6).

a b c d e f g h i 0 ~ 60 gradation 0.750 0.625 0.500 0.500 0.375 0.375 0.250 0.250 0.125 60 to 120 gradations 1.125 1.000 0.875 0.750 0.625 0.500 0.375 0.250 0.125 More than 120 gradations 2.250 2.000 1.750 1.500 1.250 1.000 0.750 0.500 0.250

12 and 3, in the data compensation method according to an exemplary embodiment of the present invention, when the compensation value is not applied, the non-overlapping surface of the second reference plane MR2 in each of the low gray range, the mid gray range, and the high gray range The luminance measured at and the luminance measured at the non-overlapping surface of the second panel defect surface MR2 are compared. According to the present invention, the compensation value to be applied to the entire surface of the non-overlapping surface of the second panel defect surface MR2 is determined to be the same constant value based on the luminance difference determined as a result of the luminance comparison, and the fifth and sixth overlapping surfaces ( GA5, GA6) are determined as constant values that vary gradually.

Low gradation  Coverage of scope

The difference between the luminance of the low gray scale range measured on the non-overlapping surface of the second panel defect surface MR2 and the luminance of the low gray scale range measured on the non-overlapping surface of the second reference surface MR2 is approximately '0.750'. Corresponds to On the non-overlapping front surface a of the second panel defect surface MR2 so that the non-overlapping surface brightness of the second panel defect surface MR2 and the non-overlapping surface luminance of the second reference plane MR2 are the same in the low gradation range. The compensation value of the low gradation range to be applied is determined as '0.750'.

The luminance of the fifth and sixth overlapping surfaces GA5 and GA6 to which the compensation value is not applied gradually increases toward the right. Therefore, in the fifth overlapping surface GA5, the low gray range compensation value in the b section is '0.625', the low gray range compensation value in the c section is '0.500', and the low gray range compensation value in the d section is '0.500', e The low gray scale compensation value of the section may be determined as '0.375', respectively. The low gradation range compensation values lowering toward the right side are added to the low gradation range digital video data to be displayed in each section of the fifth overlapping surface GA5. In the sixth overlapping surface GA6, the low gray range compensation value of the f interval is '0.375', the low gray range compensation value of the g interval is '0.250', the low gray range compensation value of the h interval is '0.250', and The low gray scale compensation value may be determined as '0.125', respectively. The lowering compensation values are added to the digital video data of the low gradation range to be displayed in the sections of the sixth overlap plane GA6.

Halftone  Coverage of scope

In the state where the compensation value is not applied, the luminance of the halftone range measured at the non-overlapping plane of the second panel defect surface MR2 and the luminance of the halftone range measured at the non-overlapping plane of the second reference plane MR2 are measured. The difference corresponds to a gradation value of approximately '1.125'. On the non-overlapping front surface a of the second panel defect surface MR2 such that the non-overlapping surface luminance of the second panel defect surface MR2 and the non-overlapping surface luminance of the second reference surface MR2 are the same in the halftone range. Decide the compensation value of the low gradation range to be applied as '1.125'.

In the fifth overlapping surface GA5, the halftone compensation value of section b is '1.000', the halftone compensation value of section c is '0.875', the halftone compensation value of section d is '0.750', and the second section The halftone compensation value of can be determined as '0.625', respectively. These lower halftone compensation values are added to the digital video data of the halftone range to be displayed in the respective sections of the fifth overlapping surface GA5. In the sixth overlapping surface GA6, the halftone compensation value of section f is '0.500', the halftone compensation value of section g is '0.375', the halftone compensation value of section h is '0.250', and the second section The halftone compensation value of may be determined as '0.125', respectively. These lowering compensation values are added to the digital video data of the halftone range to be displayed in the respective sections of the sixth overlap plane GA6.

High gradation  Coverage of scope

In the state where the compensation value is not applied, the luminance of the high gradation range measured on the non-overlapping surface of the second panel defect surface MR2 and the luminance of the high gradation range measured on the non-overlapping surface of the second reference surface MR2 The difference corresponds to a gray scale value of approximately '2.250'. On the non-overlapping front surface a of the second panel defect surface MR2 such that the non-overlapping surface luminance of the second panel defect surface MR2 and the non-overlapping surface luminance of the second reference surface MR2 are the same within a high gradation range. Decide the compensation value of the high gradation range to be applied as '2.250'.

In the fifth overlapping surface GA5, the high gradation range compensation value of the b section is '2.000', the high gradation range compensation value of the c section is '1.750', the high gradation range compensation value of the d section is '1.500', and the e section The high gray scale compensation value of may be determined as '1.250', respectively. The lowering of the high gradation range compensation values toward the right side is added to the digital video data of the high gradation range to be displayed in the respective sections of the fifth overlapping surface GA5. In the sixth overlapping surface GA6, the high gray scale compensation value of the f interval is '1.000', the high gray scale compensation value of the g interval is '0.750', the high gray scale compensation value of the h interval is '0.500', and the i interval The high gray scale compensation value of may be determined as '0.250', respectively. The lowering compensation values are added to the digital video data of the high gradation range to be displayed in the sections of the third overlapping surface GA3.

As a result of the application of the compensation value, the compensation luminance of the second panel defect surface MR2, the fifth and sixth overlapping surfaces GA5 and GA6 is substantially equal to the non-overlapping surface luminance of the second reference surface MR2 in the entire gray scale range that can be expressed. Will be the same.

10 to 12, the correction values determined between adjacent sections of the overlapping surfaces GA1 to GA6 are set at equal intervals therebetween. On the contrary, since the curves of the measured luminance measured in the overlapping surfaces GA1 to GA6 are nonlinear as shown in FIGS. 10 to 12, the compensation values between adjacent sections in the overlapping surfaces GA1 to GA6 may be determined as nonlinear differences. have. Even in the latter case, the compensation value between adjacent sections of the overlapping surfaces GA1 to GA6 should be determined within a difference of less than 0.5 gray scales so that no boundary is shown.

13 illustrates a dither pattern of the FRC for expressing the above-described compensation values in digital video data.

Referring to FIG. 13, the FRC of the data compensation method according to the embodiment of the present invention has a size of 8 pixels x 8 pixels and the number of pixels to which '1' is added is set differently according to the compensation value to a fractional gray scale less than 1. 1/8 dither patterns to 8/7 dither patterns expressing corresponding compensation values are used.

The 1/8 dither pattern sets 8 pixels to which '1' is added among the 64 pixels to express a compensation value corresponding to 1/8 (= 0.125) gray scale, and the 2/8 dither pattern shows 64 pixels. 16 pixels to which '1' is added are set to express a compensation value corresponding to 2/8 (= 0.250) gray scale, and 3/8 dither pattern is 24 pixels to which '1' is added among 64 pixels. Set these to represent the compensation value corresponding to 3/8 (= 0.375) gradation. The 4/8 dither pattern sets 32 pixels to which '1' is added among 64 pixels to express a compensation value corresponding to 4/8 (= 0.500) gray scale, and the 5/8 dither pattern is 64 pixels 40 pixels to which '1' is added are set to express a compensation value corresponding to 5/8 (= 0.625) gray scale, and the 6/8 dither pattern is 48 to which '1' is added among 64 pixels. The pixels are set to represent a compensation value corresponding to 6/8 (= 0.750) gray scale. The 7/8 dither pattern expresses a compensation value corresponding to 7/8 (= 0.875) gray level by setting 56 pixels to which '1' is added among 64 pixels. Each of these dither patterns changes the positions of pixels to which '1' is added every frame period.

Among the dither patterns, dither patterns of less than 0.5 gradations are used for the dither patterns between the adjacent sections a to i such that no boundary is visible between the adjacent sections a to i in the overlapping surfaces GA1 to GA6.

14 illustrates a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 14, a liquid crystal display according to an exemplary embodiment of the present invention includes a display panel in which a thin film transistor TFT for intersecting data lines 166 and gate lines 168 and driving a liquid crystal cell Clc is formed at an intersection thereof. 163; Digital video data Rc / Gc / Bc compensated by modulating digital video data Ri, Bi, Gi to be supplied to the panel defect surfaces MR1 and MR2 and overlapping surfaces GA1 to GA6 of the display panel 163. Compensation circuit 165 for generating a; A data driving circuit 161 for supplying compensated data Rc / Gc / Bc to the data lines 166; A gate driving circuit 162 supplying a scan signal to the gate lines 166; And a timing controller 164 for controlling the driving circuits 101 and 102.

Liquid crystal molecules are injected into the liquid crystal display panel 163 between two substrates (a TFT substrate and a color filter substrate). The data lines 166 and the gate lines 168 formed on the TFT substrate are perpendicular to each other. The TFT formed at the intersection of the data lines 166 and the gate lines 168 receives the data voltage supplied via the data line 166 in response to a scan signal from the gate line 168 of the liquid crystal cell Clc. Supply to the pixel electrode. A black matrix, a color filter, and a common electrode (not shown) are formed on the color filter substrate. The common electrode may be formed on the TFT substrate according to the electric field application method. Polarizers having transmission axes perpendicular to each other are attached to the TFT substrate and the color filter substrate.

The compensation circuit 165 receives the input data Ri / Gi / Bi from the system interface and receives the digital video data Ri / to be displayed on the panel defect surfaces MR1 and MR2 and the overlapping surfaces GA1 to GA6. Gi / Bi) is added to a previously stored correction value to output the compensated digital video data Rc / Gc / Bc.

The timing controller 164 supplies the compensated digital video data Rc / Gc / Bc from the compensation circuit 165 to the data driving circuit 161 in accordance with the dot clock DCLK and the vertical / horizontal synchronization signal Vsync. Gate control signal GDC for controlling gate driving circuit 162 and data control signal for controlling data driving circuit 161 using Hsync, data enable signal DE, and dot clock DCLK. (DDC) is generated. The compensation circuit 165 and the timing controller 164 may be integrated into one chip.

The data driving circuit 161 converts the compensated digital video data Rc / Gc / Bc supplied from the timing controller 164 into an analog gamma compensation voltage and converts the analog gamma compensation voltage into a data voltage. To feed.

The gate driving circuit 162 sequentially supplies a scan signal for selecting a horizontal line to which a data voltage is supplied to the gate lines 168.

15 shows the compensation circuit 165 in detail.

Referring to FIG. 15, a compensation circuit 165 according to an embodiment of the present invention includes an FRC controller 171, an EEPROM 172, a register 173, and an interface circuit 174.

The FRC control unit 171 determines the display position of the digital video data Ri, Bi, Gi according to the vertical and horizontal synchronization signals Vsync and Hsync, the data enable signal DE, and the dot clock DCLK. The determination result is compared with the positional information PD from the EEPROM 172 to detect digital video data Ri, Bi, Gi to be displayed on the panel defect surfaces MR1 and MR2 and the overlapping surfaces GA1 to GA6. If the FRC control unit 171 determines that the digital video data Ri, Bi, or Gi is to be displayed on the pixels belonging to the panel defect planes MR1 and MR2 or the overlapping planes GA1 to GA6, the FRC control unit 171 determines the digital video data ( Ri, Bi, and Gi are used as read addresses, and the compensation value CD output from the EEPROM 172 is added to the digital video data Ri, Bi, and Gi according to the read address. . Here, the FRC control unit 171 distributes the compensation value temporally and spatially according to the predetermined dither pattern as shown in FIG. 13 and adds a compensation value of less than 1 gray scale to the digital video data Ri, Bi, and Gi in the dither pattern unit. An integer compensation value of one or more gray levels is added to the digital video data in units of pixels.

In the EEPROM 172, position data PD and a compensation value CD indicating respective pixel positions of the panel defect surfaces MR1 and MR2 and the overlapping surfaces GA1 to GA6 on the liquid crystal display panel 163 are in the form of a lookup table. Is stored as. The position data PD and the compensation value CD stored in the EEPROM 172 may be updated by an electrical signal applied from an external system through the interface circuit 174.

The interface circuit 174 is configured for communication between the compensation circuit 165 and an external system, and the interface circuit 174 is designed in accordance with a communication standard protocol standard such as I ² C. The external system may read or modify data stored in the EEPROM 172 through the interface circuit 174. That is, the position data and the compensation value CD stored in the EEPROM 172 are required to be updated due to the process change, the difference between the applied models, etc., and the user needs to update the user position data UPD and the user compensation value ( UCD) is entered through an external system. The user data UPD and UCD are stored in the EEPROM 172 through the ROM writer, the interface circuit 174, the register 173, and the FRC control unit 171.

The register 173 temporarily stores the user data UPD and CD transmitted through the interface circuit 174 to update the position data PD and the compensation data CD stored in the EEPROM 172.

Such a liquid crystal display device can be applied to other flat panel display devices without significant change. For example, the liquid crystal display panel 63 may be replaced by a field emission display device, a plasma display panel, an organic light emitting diode display device, or the like.

As described above, the data compensation method and apparatus of the flat panel display device according to the present invention are based on the luminance measured from the non-overlapping surface on each of the two display surfaces that are relatively different in luminance and overlap each other by a predetermined area. The data to be displayed on the overlapping surfaces GA1 to GA6 overlapping the two display surfaces and one of the two display surfaces, for example, the panel defect surfaces MR1 and MR2, are compensated with a predetermined compensation value. The overlapping surfaces GA1 to GA6 are converted into pixel sizes, and are virtually divided into a plurality of sections in the converted size, and the compensation values are gradually increased or increased in the sections of the overlapping surfaces GA1 to GA6 thus divided. Determined in the decreasing direction. In the progressively increasing or decreasing compensation values, the difference between compensation values corresponding to neighboring sections should be less than 0.5 gray scales so that no boundary is visible in the overlapping surfaces GA1 to GA6. Therefore, the data compensation method and apparatus of the flat panel display apparatus according to the present invention adjust the value of the digital video data to the non-uniformity of the flat panel display panel caused by the process of overlapping or lens aberration of the lens, the brightness of the display surface is partially different In the flat panel display panel, the luminance of the display surface can be made uniform.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (10)

Measuring luminance by supplying the same gray level data to the entire display surface of the flat panel display panel; The luminance of the first display surface and the second display surface is measured differently in the flat panel display panel, and the first and second display surfaces are superposed therebetween so that the luminance is different from that of the first and second display surfaces. Determining whether a face exists; By comparing the difference between the non-overlapping surface luminance of the first display surface and the non-overlapping surface luminance of the second display surface, one of the first display surface and the second display surface is selected, and Determining a first compensation value; A second compensation virtually dividing the overlapping surface into a plurality of sections and gradually changing between the sections based on a result of comparing a non-overlapping brightness of the first display surface with a non-overlapping brightness of the second display surface Determining values; And Adjusting digital video data to be displayed on the selected display surface to the first compensation value and adjusting data to be displayed on the overlapping surface to the second compensation values. Compensation Method. The method of claim 1, And the second compensation values determined corresponding to each of the adjacent sections in the overlapping surface have a difference of less than 0.5 gray scales. The method of claim 1, And wherein the selected display surface is a display surface having a lower brightness among the first display surface and the second display surface. The method of claim 1, The overlapping surface, A first overlapping surface of which brightness is gradually lowered toward a non-overlapping surface of a relatively dark display surface of the first display surface and the second display surface; And a second overlapping surface of which the luminance is gradually increased toward the non-overlapping surface of the relatively bright display surface of the first display surface and the second display surface. The method of claim 4, wherein Each of the first and second overlapping surfaces is virtually divided into the plurality of sections, And the second compensation values are determined to correspond to 1: 1 in each of the sections, and change with a gradual difference in adjacent sections. The method of claim 5, The second compensation values for the first overlapping surface include constant values that gradually increase toward a non-overlapping surface of the relatively dark display surface;  And the second compensation values for the second overlapping surface include constant values gradually decreasing toward the non-overlapping surface of the relatively bright display surface. Flat panel display panel; As a result of measuring luminance by supplying the same gray scale data to the entire display surface of the flat panel display panel, a first display surface of any one of the first display surface and the second display surface whose luminance is measured differently in the flat panel display panel is measured. A compensation value, a second compensation value for the overlapping surface where the first and second display surfaces overlap and appear to be different from the luminance of the first and second display surfaces, and the position information of the selected display surface and the overlapping surface. Memory for storing; Receiving digital video data and a timing signal and detecting digital video data to be displayed on the selected display surface and the overlapping surface as a result of the comparison between the timing signal and the position information, and displaying the digital video data to be displayed on the selected display surface. A data compensator for adjusting data to be displayed on the overlapping surface to the second compensation values while adjusting to a compensation value; And And a driving unit which receives the digital video data adjusted by the data compensator and drives the flat panel display panel. The method of claim 7, wherein And the second compensation values determined corresponding to each of the adjacent sections in the overlapping surface have a difference of less than 0.5 gray scales. The method of claim 7, wherein The data compensation unit, And distributing the compensation values in a dither pattern of 8 pixels by 8 pixels, and distributing the dither patterns in time by changing a frame period unit. The method of claim 7, wherein The flat panel display panel, And a liquid crystal display device, a field emission display device, a plasma display panel, and an organic light emitting diode display device.

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