KR20060028919A - How to calibrate the gradation data for driving the electron emission display panel - Google Patents

Abstract

The present invention includes steps (a) to (f) as a method of correcting grayscale data for driving an electron emission display panel. In step (a), luminance values corresponding to each grayscale are measured to obtain a first lookup table. In step (b), the measured luminance values are normalized to obtain a second lookup table. In step (c), the second lookup table is used to calculate the gamma value of each gradation that generates each of the normalized luminance values. In step (d), an inverse gamma value, which is the inverse of the gamma value of each of the gray levels, is calculated. In step (e), each of the gradations is multiplied by the respective inverse gamma value to obtain a correction lookup table. In step (f), the gradation data is converted according to the correction lookup table.

Description

Method of correcting gray-scale data for driving electron emission display panel

1 is a block diagram illustrating a gradation-data correction system according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view illustrating the electron emission display panel of FIG. 1. FIG.

FIG. 3 is a flowchart illustrating an operation algorithm of the gradation-data correction system of FIG. 1.

4 is an example of a graph drawn by a first look-up table in step S1 of FIG. 3.

FIG. 5 is an example of a graph drawn by a second look-up table in step S2 of FIG. 3.

FIG. 6 is a graph showing that the linearity of luminance with respect to the gray scale data is improved when the gray scale data is corrected by the look-up table in step S6 of FIG. 3.

<Description of the symbols for the main parts of the drawings>

EED ... electronic emission display device, 1 ... electronic emission display panel,                 

4 ... video control element, 5 ... set-top box,

6 ... panel control element, LUT ... lookup table,

7 scan drive element, 8 data drive element,

The present invention relates to a method of driving an electron emission display panel, and more particularly, to a method of correcting grayscale data for driving an electron emission display panel.

A conventional electron emission display device, for example, the electron emission display device of Japanese Patent Laid-Open No. 242,214 (name of the invention: field emission type image display device) in 2000 is an electron emission display panel, a panel control element, a scan drive element. , And data driving elements. The panel control element processes the image signal to generate scan-driven control signals and data-driven control signals. The scan drive element drives the scan electrode lines of the electron emission display panel in accordance with scan-drive control signals from the panel control element. The data driving element drives the data electrode lines of the electron emission display panel in accordance with data-driven control signals from the panel control element.

In the conventional electron emission display device as described above, there is a problem that the linearity of luminance with respect to the grayscale data input from the panel control element to the data driving element is lowered for driving the electron emission display panel.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of correcting grayscale data such that the linearity of luminance with respect to grayscale data for driving an electron emission display panel is improved.

The present invention for achieving the above object, as a method for correcting the grayscale data for driving the electron emission display panel, comprises the steps (a) to (f). In step (a), luminance values corresponding to each grayscale are measured to obtain a first lookup table. In step (b), the measured luminance values are normalized to obtain a second lookup table. In step (c), the second lookup table is used to calculate the gamma value of each gradation that generates each of the normalized luminance values. In step (d), an inverse gamma value, which is the inverse of the gamma value of each of the gray levels, is calculated. In step (e), each of the gradations is multiplied by the respective inverse gamma value to obtain a correction lookup table. In step (f), the gradation data is converted according to the correction lookup table.

According to the correction method of the present invention, since the correction is performed by multiplying the respective inverse gamma values by each of the gray scales, the linearity of the luminance with respect to the gray scale data can be improved as a result of the synthesis.

Hereinafter, preferred embodiments according to the present invention will be described in detail.

Referring to FIG. 1, an electron emission display apparatus EED according to an embodiment of the present invention includes an electron emission display panel 1 and a driving device thereof. The driving device of the electron emission display panel 1 includes an image control device 4, a set top box 5, a panel control device 6, a scan drive device 7, a data drive device 8, and a power supply unit 9. ).

Image control device 4 includes a panel control to process the video signal from the video signal (S _PC), DVD (digital versatile disk) video signal from the player (S _DVD), and a set top box (5) from the computer device ( 6). The set top box 5 converts the video signal STV from the _television and inputs it to the video control element 4.

The panel control element 6 processes the image signal from the image control element 4 to generate scan-drive control signals S _SIN and data-drive control signals S _DIN . In the manufacturing process of the electron emission display device EED, the correction lookup table LUT output from the gradation-data correction system 9 is stored in the internal memory of the panel control element 6. The correction algorithm of the gradation-data correction system 9 will be described in detail with reference to Figs. The grayscale data included in the data-driven control signals S _DIN is the data of the result corrected by the correction lookup table LUT stored in the internal memory of the panel control element 6.

The scan drive element 7 performs gate electrode lines G ₁ ,..., G _n of the electron emission display panel 1 in accordance with the scan-drive control signals S _SIN from the panel control element 6. Drive

The data driving element 8 comprises the cathode electrode lines C _1R , ..., C _1600B of the electron emission display panel 1 in accordance with the data-driven control signals S _DIN from the panel control element 6. To drive.

To the cathode electrode lines C _1R , ..., C _1600B as the data electrode lines while the scan pulse is sequentially applied to the gate electrode lines G ₁ ,..., G _n as the scan electrode lines. The gray scale display is performed by the width of the data pulses applied.

Referring to FIG. 2, in the field emission display panel 1 of FIG. 1, the front panel 2 and the rear panel 3 are supported by space bars 41,..., 43. Here, in addition to the space bars 41,..., 43 shown in FIG. 2, a plurality of space bars exist on the second gate electrode plate 36.

The rear panel 3 comprises a rear substrate 31, cathode electrode lines C _1R , ..., C _1600B , electron emitters E _{(1) 1R} , ..., E _{(n) 1600B} , The first insulating layer 33, the first gate electrode lines G ₁ ,..., G _n , the second insulating layer 35, and the second gate electrode plate 36 are included.

The cathode electrode lines C _1R ,..., C _1600B to which data signals are applied are electrically connected to the electron emission sources E _{(1) 1R} ,..., E _{(n) 1600B} . Electron emission sources E are formed in the first insulating layer 33, the first gate electrode lines G ₁ ,..., G _n , the second insulating layer 35, and the second gate electrode plate 36. Through holes H _{(1) 1R} , ..., H _{(n) 1600B} corresponding to _{(1) 1R} , ..., E _{(n) 1600B} are formed. Therefore, in the first gate electrode lines G ₁ ,..., G _n to which the scan signals are applied, the through holes H are intersected with the cathode electrode lines C _1R ..., C _1600B . _{(1) 1R} , ..., H _{(n) 1600B} ) is formed. The focusing signal is applied to the second gate electrode plate 36.

The front panel 2 includes a front transparent substrate 21, a positive electrode plate 22, and fluorescent cells F _{(1) 1R} ,..., F _{(n) 1600B} . The fluorescent cells F _{(1) 1R} , ..., F _{(n) 1600B} correspond to the through holes H _{(1) 1R} , ..., H _{(n) 1600B} of the second gate electrode plate 36. Is formed. In the positive electrode plate 22, electrons from the electron emission sources E _{(1) 1R} , ..., E _{(n) 1600B} are transferred to the fluorescent cells F _{(1) 1R} , ..., F _{(n) 1600B} . A high positive potential of 1-4 kilovolts (KV) is applied to move.

3 to 6, the operation algorithm of the gradation-data correction system 9 of Fig. 1 will be described.

In step S1, luminance values corresponding to each grayscale are measured, and a first lookup table is obtained. 4 is an example of a graph drawn by a first look-up table in step S1 of FIG. 3. In FIG. 4, C _R1 denotes a characteristic curve of red cells, C _B1 denotes a characteristic curve of blue cells, and C _G1 denotes a characteristic curve of green cells, respectively.

In step S2, the measured luminance values are normalized, and a second lookup table is obtained. FIG. 5 is an example of a graph drawn by a second look-up table in step S2 of FIG. 3. In FIG. 5, C _R2 denotes a characteristic curve of red cells, C _B2 denotes a characteristic curve of blue cells, and C _G2 denotes a characteristic curve of green cells, respectively. Referring to FIG. 5, it can be seen that the linearity of luminance with respect to the gray scale data is reduced. In step S2, if the luminance value corresponding to any one gray level is B _G , the maximum gray level is G _P , the luminance value corresponding to the maximum gray level is B _P , and the normalized luminance value corresponding to any one gray level is Y _G , Normalized luminance value Y _G is obtained by Equation 1 below.

이면, 아래의 수학식 2에 의하여 상기 감마 값이

이 구해진다.In step S3, the second lookup table is used to calculate a gamma value of each gray level that generates each of the normalized luminance values. Here, one gray level is x, and the gamma value

, The gamma value is determined by Equation 2 below.

Is obtained.

이 구해진다. In other words, the gamma value is expressed by Equation 3 below.

Is obtained.

)이 계산된다. In step S4, the inverse gamma value (the inverse of the gamma value of each grayscale)

) Is calculated.

In step S5, each of the gradations is multiplied by the respective inverse gamma value to obtain a correction lookup table. In other words, each of the gray scales and the corresponding gray scales corresponding thereto is recorded in the correction lookup table.

In step S6, a correction lookup table obtained by performing step S5 is output.

Accordingly, in the manufacturing process of the electron emission display device EED, the correction lookup table (LUT in FIG. 1) from the gradation-data correction system 9 is stored in the internal memory of the panel control element (6 in FIG. 1). .

)이 곱해진 경우의 역감마 특성 곡선을, 그리고 C_RC는 상기 감마 특성 곡선(C_R2)과 역감마 특성 곡선(C_R3 )의 합성 곡선을 각각 가리킨다. 도 6을 참조하면, 도 3의 단계 S6에서의 보정 룩업 테이블(Look-Up Table)에 의하여 계조-데이터가 보정된 경우, 상기 합성 곡선(C_RC)에 따라 계조 데이터에 대한 휘도의 선형성이 향상됨을 알 수 있다. The panel control element 6 converts the grayscale data among the image signals from the image control element 4 into corrected grayscale data according to the correction lookup table (LUT in FIG. 1). In other words, the gradation data included in the data-driven control signals S _DIN is the data of the result corrected by the correction lookup table LUT stored in the internal memory of the panel control element 6. In FIG. 6, reference numeral C _R2 denotes the original gamma characteristic curve of the red cells, and C _R3 denotes each inverse gamma value (the gray scale of the original characteristic curve C _R2 of the red cells).

Inverse gamma characteristic curve when) is multiplied, and C _RC indicates a synthesis curve of the gamma characteristic curve (C _R2 ) and inverse gamma characteristic curve (C _R3 ), respectively. Referring to FIG. 6, when the gray scale data is corrected by the look-up table in step S6 of FIG. 3, the linearity of luminance with respect to the gray data is improved according to the synthesis curve C _RC . It can be seen.

As described above, according to the method for correcting the gray scale data for driving the electron emission display panel according to the present invention, since the correction is performed by multiplying the respective inverse gamma values to each gray scale, the gray scale as a result of the synthesis is performed. The linearity of the luminance over the data can be improved.

The present invention is not limited to the above embodiments, but may be modified and improved by those skilled in the art within the spirit and scope of the invention as defined in the claims.

Claims (5)

A method of correcting grayscale data for driving an electron emission display panel, (a) measuring luminance values corresponding to each grayscale to obtain a first lookup table; (b) normalizing the measured luminance values to obtain a second lookup table; (c) using the second lookup table, calculating a gamma value of each gradation that generates each of normalized luminance values; (d) calculating an inverse gamma value that is an inverse of the gamma value of each gray level; (e) multiplying each gray level by the respective inverse gamma value to obtain a correction lookup table; And and (f) converting the gradation data according to the correction lookup table. The method of claim 1, wherein in step (f), The correction lookup table is stored in the drive of the electron emission display panel (1). The method of claim 1, wherein in step (b), If the luminance value corresponding to one gray level is B _G , the maximum gray level is G _P , the luminance value corresponding to the maximum gray level is B _P , and the normalized luminance value corresponding to any one gray level is Y _G ,

And the normalized luminance value Y _G is obtained by the following equation. The method of claim 3, wherein in step (c), The gray level is x, and the gamma value is

If,

The gamma value according to the equation

The correction method in which this is calculated. The method of claim 4, wherein in step (c),

The gamma value according to the equation

The correction method in which this is calculated.

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