KR20160026680A - Luminance compensation equipment and system and luminance compensation method - Google Patents

Abstract

The purpose of the present invention is to provide a luminance compensation method of an organic EL display which takes less time to measure even though the compensation for luminance non-uniformity is carried out on each cell. The luminance compensation method successively has a photography level, a characteristic calculation level, and a compensation level. In case of the photography level, the color of a sub pixel of the pixel of a display (100) is displayed on a display (100) with a pattern which is the common gray scale of each pixel and can separate each pixel. A camera (10) photographs the entire pattern displayed on the display (100) at the same time, and corresponding photography is successively performed on each sub pixel and gray scales. In case of the characteristic calculation level, a process part (21) calculates the luminance characteristic for the gray scale of each sub pixel. In case of the compensation level, a control part (23) compensates the luminance characteristic of each pixel for the display (100) based on luminance characteristic obtained by the characteristic calculation level.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a luminance compensating apparatus,

The present invention relates to a luminance correction method of a display.

In order to correct the luminance unevenness of the LCD or LED display, a correction coefficient is calculated from the luminance measured by the camera and the luminance unevenness is corrected based on the correction coefficient.

In the organic EL display, since there is a deviation from pixel to pixel, a correction method in which the luminance changes spatially and gently as in the correction of the LCD can not be used. In addition, when the correction technique of the LCD is used, correction for each pixel can not be performed, so that it is not possible to cope with high-definition display. Although the LED display has a luminance variation for each pixel, the characteristics of luminance with respect to gradation can be expressed by a simple expression, whereas the characteristics of OLED differ from pixel to pixel.

Therefore, for an organic EL display, a system has been proposed in which a part of a display is enlarged and photographed, and the luminance of each pixel is measured while moving the camera (see, for example, Patent Document 1). However, the technique disclosed in Patent Document 1 has a problem that measurement takes time because the camera is moved. In addition, alignment of the camera and the display takes time. If the number of measured gradations is increased in order to obtain the characteristic of luminance with respect to the gradation, there is a problem that it takes more time. Since the moire occurs in the photographed image, it is processed by software but there is a problem that the measured value is influenced when there is luminance unevenness of the same frequency component.

Further, as a method of correcting the luminance of the organic EL display, a system in which the current supplied to the pixel is monitored to correct the current can be considered. However, this method has a problem in that it is not applicable to a small-sized panel because there is a problem of mounting a dedicated chip on a substrate. Further, there is a problem that the actual luminance can not be fully reflected only by monitoring the current, and the effect can not be confirmed.

Japanese Patent Application Laid-Open No. 11-170106

As described above, in the organic EL display, there is a problem that measurement time is required if the luminance unevenness is corrected for each pixel. It takes time to measure, and it is not available at the production site.

Therefore, it is an object of the present invention to provide a luminance correction method of an organic EL display which does not require a measurement time even if correction of luminance unevenness is performed for each pixel.

Specifically, the luminance correction apparatus according to the present invention comprises:

A display control section for displaying the color of one sub-pixel constituting a pixel of the display on the display in a pattern in which each pixel has a common gradation and in which each pixel can be separated;

A processing section for calculating luminance characteristics for the gradations of the individual sub-pixels by using an image obtained by simultaneously imaging all of the patterns displayed on the display and for each of the sub-pixels and the plurality of gradations,

And a correction control section for correcting the luminance characteristic of each sub-pixel with respect to the display based on the luminance characteristic obtained by the processing section.

In the brightness correction apparatus according to the present invention, the display control section may display one or more pixels in a lattice pattern on the display by displaying the pixels on the display in a pattern capable of separating the pixels.

Specifically, the luminance correction system according to the present invention is a luminance correction system comprising: a luminance correction device according to the present invention; an image obtained by simultaneously capturing the entire pattern displayed on the display and the image picked up successively for each sub- As shown in Fig.

Specifically, the luminance correction method according to the present invention comprises:

The color of one sub-pixel constituting the pixels of the display is displayed on the display in a pattern in which each pixel has a common gradation and each pixel can be separated and the camera simultaneously captures the entire pattern displayed on the display An image pickup procedure for sequentially performing the image pickup for each sub-pixel and a plurality of gradations,

A processing section for calculating a luminance characteristic for the gradation of each sub-pixel,

And the control unit has a correction procedure for correcting the luminance characteristic of each sub-pixel with respect to the display based on the luminance characteristic obtained by the characteristic calculating procedure.

According to the present invention, it is possible to provide a luminance correction method of an organic EL display that does not require a measurement time even if correction of luminance unevenness is performed for each pixel. Further, according to the present invention, it is possible to correct the luminance non-uniformity for each pixel, so that the organic EL display which can not be shipped due to the luminance unevenness is reduced, and the yield can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a configuration example of a luminance correction system according to the present embodiment. Fig.
2 is a diagram showing an arrangement example of a first pixel of a display;
3 is a diagram showing an example of arrangement of a second pixel of a display;
Fig. 4 is a diagram showing an example of a luminance characteristic for gradation relating to one sub-pixel; Fig.
Fig. 5 is a diagram showing an example of calculation of a function L (g) showing the luminance characteristic; Fig.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below. These embodiments are merely illustrative, and the present invention can be carried out in various modifications and improvements based on knowledge of those skilled in the art. In the specification and drawings, the same reference numerals denote the same elements.

Fig. 1 shows an example of a luminance correction system according to the present embodiment. The luminance correction system according to the present embodiment includes a camera 10 and a luminance correction device 20. [ The luminance correction apparatus 20 includes a processing unit 21, a storage unit 22, and a control unit 23. [ The control unit 23 functions as a display control unit for controlling the display operation of the display 100 and a correction control unit for controlling the brightness of the display 100 for each pixel.

The luminance correction device 20 may be implemented by causing the computer to function as the processing unit 21 and the control unit 23. [ In this case, the CPU (Central Processing Unit) in the luminance correction apparatus 20 executes the computer program stored in the storage section 22 to realize each configuration.

Figs. 2 and 3 show an example of the display 100. Fig. The display 100 has pixels arranged to emit light of any colors. Each pixel includes a plurality of sub-pixels, and each sub-pixel emits light of a different color. For example, one pixel includes a red sub-pixel R _1,1 , a green sub-pixel G _1,1 , and a blue sub-pixel B _1,1 . One pixel may include a sub-pixel that emits light of other colors. For example, as shown in Fig. 2, a white sub-pixel W _1,1 may be included. Further, a plurality of sub-pixels of the same color may be included in one pixel. For example, or it may instead of the sub-pixel W _{1, 1} shown in Figure 2, is included in green sub pixels G _1,1.

The camera 10 is an area sensor capable of simultaneously imaging the entire pattern displayed on the display 100. [ The resolution is arbitrary. It is necessary to detect the gradation of the color of each pixel from the image of the entire screen of the display 100. In the case where the pixels can not be separated, the interval of the pixels to be displayed is widened. Since it is necessary to identify the gradation of the color of each sub-pixel, the camera 10 has sensitivity to the light-emitting color of the sub-pixel.

The brightness correction method according to the present embodiment has an imaging procedure, a characteristic calculation procedure, and a correction procedure in order. In the imaging procedure, the camera 10 picks up a pattern displayed on the display 100. In the characteristic calculation procedure, the processing section 21 calculates the luminance characteristic for the gradation for each of the sub-pixels. In the correction procedure, the control unit 23 outputs the coefficient acquired from the processing unit 21 to the display 100 as the correction information of the display 100. [

Details of the imaging procedure will be described. The control unit 23 displays the color of any one of the sub-pixels constituting the pixels of the display 100 on the display 100 in a common gray scale. The camera 10 picks up the entire screen of the display 100. As described above, in the present embodiment, since the enlarged photographing requiring the movement of the camera 10 is not performed, no stage is required, alignment is not strict, and there is no need for processing of seams between images.

In this embodiment, in order to measure the gradation of each pixel, the controller 23 sets the color of one of the sub-pixels constituting the pixel of the display 100 to the display 100 for each of the gradations to be measured, . At this time, the control unit 23 displays a pattern capable of separating each pixel by thinning the light-on pixels of the display 100. For example, one or more pixels are displayed in a lattice shape in the longitudinal direction, the lateral direction, or both directions. By thinning the light-on pixels, light emission among the pixels can be separated without performing enlargement photographing that requires the movement of the camera 10.

In the case of the display shown in Fig. 2, sub-pixels of different colors are arranged between sub-pixels for displaying a specific color of one pixel. If the neighboring pixels can be separated in the image captured by the camera 10, the pattern is a pattern that displays all the pixels and only one color included in the pixel. For example, R _1,1 shown in Fig. _{2, R 1,2, R 1,3,} R 2,1, R 2,2, R 2,3, R 3,1, R 3,2, R 3 _{, 3} are displayed. After imaging the red pattern, the pattern of white, blue, and green is sequentially captured.

In the case of the display shown in Fig. 3, sub pixels for displaying a specific color of one pixel are adjacent to each other in the vertical direction. In this case, if it is possible to separate every pixel in the image captured by the camera 10, the pattern is a pixel in the horizontal direction and one pixel in the vertical direction and displays only one color included in the pixel . For example, R _1,1 , R _1,3 , R _2,2 , R _3,1 , R _3,3 shown in FIG. ₃ are shown. Thereafter, unrecorded pixels, for example, R _1,2 , R _2,1 , R _2,3 , R _3,2 are displayed. After picking up a red pattern, a blue and green pattern are sequentially picked up.

Thus, each sub-pixel is imaged by the camera 10 while changing the gradation to be measured. Thereby, the processing section 21 can acquire the luminance information for each of the sub-pixels of the display 100 at a plurality of different gradations. The acquired luminance information is stored in the storage section 22. [

Here, the number of gradations to be measured is arbitrary, but the number of possible fittings of the luminance characteristic is a number. For example, in the case of Formula (1) to be described later, which is used in the present embodiment, the number of gradations is preferably 3 or more, and the number of gradations is 4 in the present embodiment.

Details of the characteristic calculation procedure will be described.

Fig. 4 shows an example of the luminance characteristic for gradation. In this procedure, the processing section 21 uses the luminance information stored in the storage section 22 to obtain a function L (g) showing a luminance characteristic having the gradation g as a variable as shown in Fig. The function L (g) is given by the following equation, for example.

L (g) = k (ag ² + bg) ^? (1)

If also the brightness of the sub-pixels R _1,1 represent the two measured for four kinds of gray scale, is plotted, that point PL ₁ to 4 of ₄ points PL as shown in Fig. At the time of deriving the coefficients a and b, a function L (g) close to the points PL ₁ to PL ₄ is obtained by using the least squares method, thereby obtaining coefficients a and b. In applying the least squares method, the weights may be different for each gradation.

The number of measurement gradations and the amount of correction data can be reduced by fitting to Equation (1) that can measure the number of gradations and display the characteristics of luminance with respect to the gradation for each pixel with a small coefficient. This makes it possible to reduce the memory usage of the storage unit 22.

The processing section 21 obtains a, b, k, and? In equation (1). a and b are obtained for each pixel. Although k and? can be obtained for each pixel, if the gamma curve is the same regardless of the pixel, one value may be obtained for the entire pixel. Since the pixel dependency of the gamma curve changes slowly in many cases, almost the same gamma curve may be obtained in the same row or column. In this case, as shown in FIG. 5, k and γ can be obtained by fitting the pixel average value of the same row or column for each gradation. When k and? Are calculated for each pixel, since a, b, k, and? Are required to be obtained for each pixel, it is desirable to perform measurement of at least four gradations and possibly five gradations or more.

By executing the characteristic calculation procedure in this manner, the processing section 21 can derive the coefficients k and? In the equation (1) and the coefficients a and b of the respective sub-pixels. Thus, the luminance characteristic of each sub-pixel can be corrected using the luminance characteristic of each sub-pixel. These coefficients are stored in the storage unit 22. At this time, the processing unit 21 may obtain an inverse function of the luminance characteristic.

Details of the correction procedure will be described.

The processing section 21 reads the coefficient from the storage section 22 and outputs it to the control section 23. The control unit 23 outputs the coefficient acquired from the processing unit 21 to the display 100 as the correction information of the display 100. [ At this time, the control unit 23 may output the inverse function of the luminance characteristic to the display 100 as a function for correction of the display 100. [ The display 100 uses the obtained coefficient or inverse function to correct for the desired luminance characteristic for each sub-pixel.

The invention according to the present embodiment corrects the luminance characteristic for each pixel by correcting the luminance characteristic for each sub-pixel, so that the luminance deviation for each pixel unique to the organic EL display can be corrected for each pixel and for each gray scale. In addition, the system configuration is very simple compared to the measurement while moving, and the luminance per pixel can be measured in a short time.

In addition, the invention according to the present embodiment can improve the yield of panel production because the shipment standard can be satisfied by performing correction even if the panel has a large luminance unevenness and does not satisfy the shipment criterion. It is also possible to classify shipping panels.

The present invention is applicable to the display industry.

10: Camera
20: luminance correction device
21:
22:
23:
100: Display

Claims (4)

A display control section for displaying the color of one sub-pixel constituting a pixel of the display on the display in a pattern in which each pixel has a common gradation and in which each pixel can be separated;
A processing section for calculating luminance characteristics for the gradations of the individual sub-pixels by using an image obtained by simultaneously imaging all of the patterns displayed on the display and for each of the sub-pixels and the plurality of gradations,
And a correction control section for correcting the luminance characteristic of each sub-pixel with respect to the display based on the luminance characteristic obtained by the processing section. The method according to claim 1,
Wherein the display control section displays one or more pixels in a lattice pattern on the display in a pattern capable of separating each pixel by displaying the pixels on the display. An apparatus for correcting brightness, comprising: a luminance correction device according to claim 1 or 2;
And a camera for picking up an image of an entire image of the pattern displayed on the display at the same time and an image obtained by sequentially performing the image pick-up for each sub-pixel and a plurality of gradations. The color of one sub-pixel constituting the pixels of the display is displayed on the display in a pattern in which each pixel has a common gradation and each pixel can be separated and the camera simultaneously captures the entire pattern displayed on the display An image pickup procedure for sequentially performing the image pickup for each sub-pixel and a plurality of gradations,
A processing section for calculating a luminance characteristic for the gradation of each sub-pixel,
Wherein the control unit sequentially has a luminance characteristic of each sub-pixel with respect to the display, and a correction procedure that corrects the luminance characteristic of each sub-pixel based on the luminance characteristic obtained by the characteristic calculation procedure.

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