Organic light emitting display and degradation compensation method thereof

Patent metadata

Field	Value
Publication number	US-9401110-B2
Application number	US-201314053899-A
Country	US
Kind code	B2
Filing date	Oct 15, 2013
Priority date	Dec 10, 2012
Publication date	Jul 26, 2016
Grant date	Jul 26, 2016

Abstract

An organic light emitting display includes a display panel including a plurality of pixels, a compensation area setting unit for selecting an additional compensation requirement area, that is more excessively degraded than an average degradation, based on degradation detection data indicating a degradation degree of organic light emitting diodes formed in the pixels, an edge information extraction unit that analyzes input image data corresponding to the additional compensation requirement area and obtains edge information of an input image, a compensation gain calculation unit for differentially calculating a compensation gain to be applied to compensation data in each of the compensation blocks belonging to the additional compensation requirement area based upon an amount of edge information; and a data modulation unit producing modulation image data to be displayed on the display panel.

First claim

What is claimed is:

1. An organic light emitting display comprising:
a display panel including a plurality of pixels each having an organic light emitting diode, the display panel displaying a visual image; and
a degradation compensation circuit comprising:
a compensation area setting circuit to divide input image data into M×N compensation blocks, where M and N are integers greater than 0 and each compensation block corresponds to a group of pixels of the plurality of pixels, and select an additional compensation requirement area that includes compensation blocks corresponding to pixels that are more excessively degraded than those pixels in an averagely degraded area, based on degradation detection data indicating a degradation degree of the organic light emitting diodes of the plurality of pixels;
an edge information extraction circuit to analyze the input image data corresponding to the additional compensation requirement area and obtain edge information of the input image data, including a number of edges;
a compensation gain calculation circuit to calculate a compensation gain to be applied to compensation data in each of the compensation blocks in the additional compensation requirement area depending on the number of edges, and does not change the compensation data of each compensation block which is not in the additional compensation requirement area, wherein the compensation gain in the additional compensation requirement area is inversely proportional to the number of edges; and
a data modulation circuit to multiply compensation data of each pixel, to which the compensation gain is applied, by the input image data and produce modulation image data to be displayed on the display panel.

2. The organic light emitting display of claim 1 , wherein the compensation area setting circuit calculates the compensation data of each pixel for compensating for a luminance of each of the pixels based on the degradation detection data,
wherein the compensation area setting circuit divides a compensation image implemented by the compensation data into the plurality of compensation blocks and finds the average picture level (APL) indicating an average brightness of each of the compensation blocks,
wherein the compensation area setting circuit selects compensation blocks having an APL greater than a reference APL as the additional compensation requirement area for adjustment of the compensation gain.

3. The organic light emitting display of claim 1 , wherein the compensation gain calculation circuit calculates the compensation gain of the compensation blocks within a range less than ‘1’ based upon the number of edges the additional compensation requirement area includes.

4. The organic light emitting display of claim 3 , wherein the compensation gain is obtained by the following Equation:

G
⁡

(

M
,
N

)

=

max
⁡

[

1
-

k
×

(

A
⁢

⁢
P
⁢

⁢

L
⁡

(

M
,
N

)

-

Ref
.

⁢
A

⁢

⁢
P
⁢

⁢
L

)

2
i

,
Gmin

]

where ‘G(M,N)’ is the compensation gain of each compensation block, ‘k’ is a scale constant, ‘APL(M,N)’ is an average picture level (APL), an average brightness, of each compensation block, ‘Ref. APL’ is a reference APL corresponding to brightness of the averagely degraded area, ‘2 i ’ is a maximum gray representation value determined depending on a number ‘i’ of bits of the input image data, and ‘Gmin’ is a minimum value of the compensation gain G (M,N) which is previously set to a fixed value so as to prevent the distortion of the image.

5. The organic light emitting display of claim 4 , wherein the scale constant, k, increases in proportion to the number of edges in each compensation block.

6. The organic light emitting display of claim 1 , wherein after the compensation gain of each compensation block is determined, the compensation gain calculation circuit applies a low pass filter to each compensation block in the additional compensation requirement area and reduces a deviation between the compensation gains of adjacent compensation blocks.

7. The organic light emitting display of claim 1 , wherein the compensation gain calculation circuit interpolates the compensation gain of each compensation block and calculates a compensation gain to be applied to each pixel.

8. The organic light emitting display of claim 1 , wherein the compensation gain calculation circuit calculates the compensation gain of the compensation blocks such that the compensation gain of the compensation blocks in the additional compensation requirement area which includes a larger number of edges becomes smaller than the compensation gain of the compensation blocks in the additional compensation requirement area which includes a smaller number of edges.

9. A degradation compensation method of an organic light emitting display, the organic light emitting display including a display panel having a plurality of pixels to display a visual im

Assignees

• Lg Display Co Ltd

Inventors

• Lee Jiwon
• Kim Seonggyun

Classifications

• G09G2320/0686

  with two or more screen areas displaying information with different brightness or colours · CPC title

• G09G2320/046

  Dealing with screen burn-in prevention or compensation of the effects thereof · CPC title

• G09G2320/0295

  by monitoring each display pixel · CPC title

• G09G3/3208 Primary

  organic, e.g. using organic light-emitting diodes [OLED] · CPC title

• G09G2320/045

  Compensation of drifts in the characteristics of light emitting or modulating elements · CPC title