Organic light emitting display device and driving method thereof

Patent metadata

Field	Value
Publication number	US-10019939-B2
Application number	US-201615140332-A
Country	US
Kind code	B2
Filing date	Apr 27, 2016
Priority date	Jun 1, 2015
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

An organic light emitting display device includes a display panel having pixels and a display panel driver driving the display panel. Each of the pixels includes an organic light emitting diode, and the display panel driver selects one of the pixels, determines a reference grayscale value, compares a grayscale value, and determines the selected pixel as a low grayscale pixel when the grayscale value is lower than the reference grayscale value and higher than a black grayscale value. Some of the low grayscale pixels display the black grayscale value when there are more than one neighboring low grayscale pixels. The reference grayscale value is determined based on a reference grayscale variable, and the reference grayscale variable includes at least one of a temperature of the display panel, a time period when the selected pixel emits light, and a wavelength of light emitted by the selected pixel.

First claim

What is claimed is:

1. An organic light emitting display device comprising:
a display panel comprising pixels, each of the pixels comprising an organic light emitting diode; and
a display panel driver configured to drive the display panel,
wherein the display panel driver is configured to:
select one of the pixels,
determine a reference grayscale value which corresponds to the selected pixel,
compare a grayscale value which corresponds to the selected pixel with the reference grayscale value, and
identify the selected pixel as a low grayscale pixel when the grayscale value which corresponds to the selected pixel is lower than the reference grayscale value and higher than a black grayscale value,
wherein the low grayscale pixel displays the black grayscale value when there are more than one adjacent low grayscale pixels,
wherein the reference grayscale value is determined based on a reference grayscale variable,
wherein the reference grayscale variable comprises at least one of a temperature of the display panel, a time period when the selected pixel emits light, and a wavelength of light emitted by the selected pixel,

wherein the pixels are arranged in a first direction and a second direction crossing the first direction,
wherein the low grayscale pixel does not display the black grayscale value when the low grayscale pixel is adjacent the low grayscale pixel displaying the black grayscale value, and
wherein the low grayscale pixel displays the black grayscale value when the low grayscale pixel is adjacent the low grayscale pixel not displaying the black grayscale value.

2. The organic light emitting display of claim 1 ,
wherein the reference grayscale variable comprises the temperature of the display panel,
wherein the reference grayscale value is determined as a first reference grayscale value when the temperature of the display panel is a first temperature,
wherein the reference grayscale value is determined as a second reference grayscale value when the temperature of the display panel is a second temperature which is greater than the first temperature, and
wherein the second reference grayscale value is higher than the first reference grayscale value.

3. The organic light emitting display of claim 1 ,
wherein the reference grayscale variable comprises the wavelength of light emitted by the selected pixel,
wherein the reference grayscale value is determined as a fifth reference grayscale value when the selected pixel emits light having a first wavelength,
wherein the reference grayscale value is determined as a sixth reference grayscale value when the selected pixel emits light having a second wavelength which is shorter than the first wavelength,
wherein the reference grayscale value is determined as a seventh reference grayscale value when the selected pixel emits light having a third wavelength which is shorter than the second wavelength, and
wherein the sixth reference grayscale value is higher than the fifth reference grayscale value and lower than the seventh reference grayscale value.

4. The organic light emitting display of claim 1 , wherein the display panel driver comprises a timing controller configured to receive image signals and timing signals from outside, the timing controller comprising a reference grayscale look-up table, and in response to the reference grayscale variable being inputted, the reference grayscale look-up table is configured to output a reference grayscale value which corresponds to the reference grayscale variable.

5. The organic light emitting display of claim 4 , wherein in response to the selected pixel being identified as the low grayscale pixel, the timing controller is configured to change the grayscale value which corresponds to the selected pixel to the black grayscale value or a grayscale value higher than the reference grayscale value which corresponds to the selected pixel.

6. An organic light emitting display device comprising:
a display panel comprising pixels, each of the pixels comprising an organic light emitting diode; and
a display panel driver configured to drive the display panel,
wherein the display panel driver is configured to:
select one of the pixels,
determine a reference grayscale value which corresponds to the selected pixel,
compare a grayscale value which corresponds to the selected pixel with the reference grayscale value, and
identify the selected pixel as a low grayscale pixel when the grayscale value which corresponds to the selected pixel is lower than the reference grayscale value and higher than a black grayscale value,
wherein the low grayscale pixel displays the black grayscale value when there are more than one adjacent low grayscale pixels,
wherein the reference grayscale value is determined based on a reference grayscale variable,

wherein the reference grayscale variable comprises at least one of a temperature of the display panel, a time period when the selected pixel emits light, and a wavelength of light emitted by the selected pixel,
wherein the reference grayscale variable comprises the time period when the selected pixel emits light,
wherein the reference grayscale value is determined as a third reference grayscale value when the selected pixel emits light in a first time period,
wherein the reference grayscale value is determined as a fourth reference grayscale value when the selected pixel emits light in a second time period which is longer than the first time period, and
wherein the fourth reference grayscale value is higher than the third reference grayscale value.

7. A method of driving an organic light emitting display device, the organic light emitting display device comprising a display panel comprising pixels and a display panel driver configured to drive the display panel, each of the pixels comprising an organic light emitting diode, the method comprising:
selecting one of the pixels;
receiving a grayscale value which corresponds to the grayscale value of the pixel;
determining a reference grayscale value which corresponds to the selected pixel;
comparing the determined reference grayscale value with the grayscale value which corresponds to the selected pixel;
identifying the selected pixel as a low grayscale pixel when the grayscale value which corresponds to the selected pixel is higher than a black grayscale value and lower than the determined reference grayscale value; and
changing grayscale values which correspond to the low grayscale pixels, wherein some of the low grayscale pixels display the black grayscale value during the changing of the grayscale values.

8. The method of driving the organic light emitting display of claim 7 , wherein the determining of the reference grayscale value which corresponds to the selected pixel comprises:
measuring a reference grayscale variable which corresponds to the selected pixel; and
determining the reference grayscale value to the reference grayscale value which corresponds to the measured reference grayscale variable.

9. The method of driving the organic light emitting display of claim 8 , wherein the measuring the reference grayscale variable comprises at least one of:
measuring a temperature of the display panel;
measuring a time period when the selected pixel emits light; and
measuring a wavelength of light emitted by the selected pixel.

10. The method of driving the organic light emitting display of claim 9 , wherein the measuring the wavelength of light comprises estimating the wavelength of the light based on a relative position of the selected pixel in the display panel.

11. The method of driving the organic light emitting display of claim 8 , wherein the determining of the referen

Assignees

• Samsung Display Co Ltd

Inventors

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

Classifications

• G09G3/3225 Primary

  using an active matrix · CPC title

• G09G2320/0686

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

• G09G2320/048

  using evaluation of the usage time · CPC title

• G09G2320/0271

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

• G09G2320/041

  Temperature compensation · CPC title