Organic light-emitting diode display and method of driving the same

Patent metadata

Field	Value
Publication number	US-2016307490-A1
Application number	US-201615019817-A
Country	US
Kind code	A1
Filing date	Feb 9, 2016
Priority date	Apr 15, 2015
Publication date	Oct 20, 2016
Grant date	—

Abstract

An organic light-emitting diode display and a method of driving the same are disclosed. In one aspect, the display includes a display panel and an image data converter configured to determine a grayscale gain based on a grayscale distribution of input image data and convert the input image data into output image data based on the grayscale gain. A display panel driver is configured to drive the display panel to display an image corresponding to the output image data, and a target current determiner is configured to determine a magnitude of a target current based on the input image data. The display also includes a power supply configured to provide a power source to the display panel and adjust the voltage level of the power source to correspond to the target current via a power line.

First claim

What is claimed is:

1 . An organic light-emitting diode (OLED) display, comprising:
a display panel including a plurality of pixels; an image data converter configured to determine a grayscale gain based on a grayscale distribution of input image data and convert the input image data into output image data based on the grayscale gain; a display panel driver configured to drive the display panel to display an image corresponding to the output image data; a target current determiner configured to determine a magnitude of a target current based on the input image data; and a power supply configured to provide a power source to the display panel and adjust the voltage level of the power source to correspond to the target current via a power line.

2 . The display of claim 1 , wherein the image data converter includes:
a grayscale distribution analyzer configured to derive the grayscale distribution from the input image data; a grayscale gain determiner configured to determine the grayscale gain based on the grayscale distribution; and an output image data generator configured to multiply the grayscale gain with the input image data so as to generate the output image data.

3 . The display of claim 2 , wherein the grayscale gain determiner is further configured to calculate an excess grayscale proportion of a plurality of grayscale values of the grayscale distribution that exceed a reference grayscale level and determine the grayscale gain corresponding to the excess grayscale proportion.

4 . The display of claim 3 , wherein the grayscale gain determiner is further configured to increase the grayscale gain when the excess grayscale proportion decreases.

5 . The display of claim 3 , wherein the grayscale gain determiner is further configured to compare the excess grayscale proportion to at least one of a plurality of threshold values and determine the grayscale gain based on the comparison.

6 . The display of claim 2 , wherein the grayscale gain determiner is further configured to determine a reference grayscale level such that an excess grayscale proportion of a plurality of grayscale values of the grayscale distribution that exceed the reference grayscale level is greater than a predetermined threshold value and determine the grayscale gain such that the reference grayscale level corresponds to a maximum output grayscale level.

7 . The display of claim 2 , wherein the grayscale gain determiner is further configured to derive a maximum input grayscale value from the grayscale distribution and determine the grayscale gain based on the maximum input grayscale value.

8 . The display of claim 1 , wherein the target current determiner is further configured to calculate the magnitude of the target current according to [Equation 1] below:
I target=ε r G r +ε g G g +ε b G b ,  [Equation 1]

wherein Itarget is the magnitude of the target current, ε r is a weight value for a red color pixel, G r is a red color grayscale value in the input image data, ε g is a weight value for a green color pixel, G g is a green color grayscale value in the input image data, ε b is a weight value for a blue color pixel, and G b is a blue color grayscale value in the input image data.

9 . The display of claim 1 , wherein the power supply includes:
a power generator configured to generate the power source; a current measurer configured to measure a magnitude of a sensing current flowing through the power line; and a power adjuster configured to compare the magnitude of the sensing current to the magnitude of the target current and adjust the voltage level of the power source such that the magnitude of the sensing current is substantially equal to the magnitude of the target current.

10 . The display of claim 9 , wherein the power source includes a first power source and a second power source, and
wherein a voltage level of the first power source is greater than a voltage level of the second power source.

11 . The display of claim 10 , wherein the power adjuster is further configured to adjust the voltage level of the first power source such that the magnitude of the sensing current is substantially equal to the magnitude of the target current.

12 . The display of claim 11 , wherein the power adjuster is further configured to decrease the voltage level of the first power source when the grayscale gain increases.

13 . The display of claim 1 , wherein the image data converter is further configured to periodically update the grayscale gain.

14 . The display of claim 13 , wherein the image data converter is further configured to update the grayscale gain every frame.

15 . The display of claim 1 , wherein the display panel driver is further configured to drive the display panel via a digital driving technique.

16 . A method of driving an organic light-emitting diode (OLED) display, the method comprising:
deriving a grayscale distribution from input image data; determining a grayscale gain based on the grayscale distribution; multiplying the grayscale gain with the input image data so as to generate output image data; determining a magnitude of a target current based on the input image data; adjusting a voltage level of a power source to provide the power source corresponding to the target current to a display panel; and displaying an image corresponding to the output image data.

17 . The method of claim 16 , wherein determining the grayscale gain includes:
calculating an excess grayscale proportion of a plurality of grayscale values of the grayscale distribution that exceed a reference grayscale level; and determining the grayscale gain such that the grayscale gain increases when the excess grayscale proportion decreases.

18 . The method of claim 16 , wherein determining the grayscale gain includes:
determining a reference grayscale level such that an excess grayscale proportion of a plurality of grayscale values that exceed the reference grayscale level is greater than a predetermined threshold value; and determining the grayscale gain such that the reference grayscale level corresponds to a maximum output grayscale level.

19 . The method of claim 16 , wherein adjusting the voltage level of the power source includes:
measuring a magnitude of a sensing current flowing through a power line; comparing the magnitude of the sensing current to the magnitude of the target current; and adjusting the voltage level of the power source based on the comparison such that the magnitude of the sensing current is substantially equal to the magnitude of the target current.

20 . The method of claim 16 , wherein the voltage level of the power source decreases when the grayscale gain increases.

Assignees

• Samsung Display Co Ltd

Inventors

• Lee Jae-Hoon
• Ryu Do-Hyung
• Park Seung-Ho
• Song Jae-Woo
• Jung Hae-Goo

Classifications

• G09G2330/023

  using energy recovery or conservation · CPC title

• G09G3/3208

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

• G09G2330/12

  Test circuits or failure detection circuits included in a display system, as permanent part thereof · CPC title

• G09G2320/0271

  Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping · CPC title

• G09G3/2007 Primary

  Display of intermediate tones · CPC title