ASSURING UNIFORMITY IN THE OUTPUT OF AN OLED

• US 20060284802A1
• Filed: 06/07/2006
• Published: 12/21/2006
• Est. Priority Date: 06/15/2005
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Inventors: Kohno, Makoto
• Granted Patent: US 7,859,492 B2
• Time in Patent Office: Days
• US Class Current: 345/76
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 3/3225 using an active matrix

Abstract

A display area of a display panel is divided into a plurality of areas, and a current detector detects a driving current (i.e. CV current) that flows when light is emitted from an area or a block including a plurality of areas. Such current detection is repeated while sequentially changing the target area or block and a CPU detects an area that has a current value different from that of other areas (i.e. an area that requires correction) based on results of the results of current detection. A similar process is performed on smaller areas obtained by subdividing the area to find a smaller area that requires correction. Thus, a correction value is obtained for each pixel and the correction values are efficiently calculated.

Claims

1. A method for making an organic EL display device, wherein the organic EL display device is formed by arranging a plurality of display pixels in a matrix pattern, each display pixel including an organic EL element, the method comprising:

dividing a display area into a plurality of predetermined detection areas to selectively cause organic EL elements of a plurality of display pixels in the detection areas to emit light to detect a driving current for each detection area;

detecting, based on driving current values detected for respective detection areas, a detection area that has a luminance value different from that of other detection areas and requires correction;

calculating correction data required for correcting image data for each pixel that is input to the detection area that requires correction; and

storing, in a memory, a position of a pixel that requires correction and related correction data calculated for the pixel.

2. The method for making an organic EL display device according to claim 1, further comprising:

subdividing the detection area that requires correction into a plurality of smaller detection areas;

performing, one time or sequentially at least two times on the smaller detection areas, the processing for detecting a smaller detection area that requires correction; and

obtaining an objective detection area as an object that requires calculation of correction data.

3. The method for making an organic EL display device according to claim 2, wherein the objective detection area, obtained as the object that requires calculation of correction data, is one display pixel or one dot in a display.

4. The method for making an organic EL display device according to claim 1, further comprising the steps of:

processing, with respect to current values detected from the divided detection areas of the display area, a plurality of predetermined detection areas including an objective detection area by multiplying a two-dimensional space filter with the detect currents, and

detecting an objective detection area that requires correction based on the result of the processing.

5. The method for making an organic EL display device according to claim 4, wherein:

detection of the driving current in each detection area is performed by sequentially changing a target position and simultaneously activating a plurality of detection areas, and

the two-dimensional space filter is calculated based on the detected results.

6. The method for making an organic EL display device according to claim 4, wherein the two-dimensional space filter has coefficients of respective detection areas, thereby giving a large weighting factor to the objective detection area, adding a value of a peripheral detection area positioned closely to the objective detection area, and subtracting a value of a peripheral detection area positioned far from the objective detection area.

7. An organic EL display device formed by arranging a plurality of display pixels in a matrix pattern, each display pixel including an organic EL element, comprising:

means for dividing a display area into a plurality of predetermined detection areas to selectively cause organic EL elements of a plurality of display pixels in the detection areas to emit light to detect a driving current for each detection area;

means for detecting, based on driving current values detected for respective detection areas, a detection area that has a luminance value different from that of other detection areas and requires correction;

means for calculating correction data required for correcting image data for each pixel that is input to the detection area that requires correction;

a memory for storing a position of a pixel that requires correction and related correction data calculated for the pixel; and

means for correcting input data with reference to the position of the pixel that requires correction and the correction data that are stored in the memory.

8. The organic EL display device according to claim 7, wherein:

the detection area that requires correction is subdivided into a plurality of smaller detection areas,

the processing for detecting a smaller detection area that requires correction is performed one time or sequentially at least two times on the smaller detection areas; and

an objective detection area is obtained as an object that requires calculation of correction data.

9. The organic EL display device according to claim 8, wherein:

the objective detection area, obtained as the object that requires calculation of correction data, is one display pixel or one dot in a display.

10. The organic EL display device according to claim 7, wherein:

with respect to current values detected from the divided detection areas of the display area, a plurality of predetermined detection areas including an objective detection area is processed by multiplying a two-dimensional space filter with the detect currents, and

an objective detection area that requires correction is detected based on the result of the processing.

11. The organic EL display device according to claim 10, wherein:

detection of the driving current in each detection area is performed by sequentially changing a target position and simultaneously activating a plurality of detection areas, and

the two-dimensional space filter is calculated based on the detected results.

12. The organic EL display device according to claim 10, wherein:

the two-dimensional space filter has coefficients of respective detection areas, thereby giving a large weighting factor to the objective detection area, adding a value of a peripheral detection area positioned closely to the objective detection area, and subtracting a value of a peripheral detection area positioned far from the objective detection area.