Organic light emitting display and method for driving the same

Patent metadata

Field	Value
Publication number	US-10672336-B2
Application number	US-201514964093-A
Country	US
Kind code	B2
Filing date	Dec 9, 2015
Priority date	Dec 11, 2014
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

Abstract

A method for driving an organic light emitting display according to an embodiment includes applying an initial value of a high potential driving power and a test pattern to a display panel and sensing changes in driving characteristics of the display panel while varying a voltage level of the high potential driving power from the initial value, deciding whether or not a sensed driving characteristic value of the display panel satisfies a predetermined condition, setting a voltage level of the high potential driving power obtained when the sensed driving characteristic value satisfies the predetermined condition, as a reference value of the high potential driving power, and adding a voltage margin to the reference value of the high potential driving power to determine a final value of the high potential driving power, and driving the display panel using the final value of the high potential driving power.

First claim

What is claimed is:

1. A method for driving an organic light emitting display, the method comprising:
applying, to a display panel, a first potential driving power having an initial value, a second potential driving power and a test pattern, wherein the first potential driving power is different than the second potential driving power;
displaying a test image by the display panel based on the test pattern and sensing a brightness of light generated from the test image by a light sensor within the organic light emitting display;
varying a voltage level of the first potential driving power and sensing a variation brightness of the display panel by the light sensor;
determining whether the variation brightness satisfies a condition that includes a change in the brightness of light being less than or equal to a reduction brightness value, setting a voltage level of the first potential driving power obtained in response to the variation brightness satisfying the condition, as a reference value of the first potential driving power, and adding a voltage margin to the reference value of the first potential driving power to determine a final value of the first potential driving power; and
driving the display panel by applying the final value of the first potential driving power to the display panel,
wherein the condition indicates that the variation brightness exists in an active region in a driving thin film transistor (TFT) drain-source voltage (Vds)-drain-source current (Ids) plane of a display panel driving operation, and the final value of the first potential driving power is less than the initial value of the first potential driving power in a saturation region in the driving TFT Vds-Ids plane of the display panel driving operation following the active region,
wherein the varying the voltage level of the first potential driving power and the sensing variation brightness of the display panel include stepwise reducing the voltage level of the first potential driving power and calculating a brightness change slope between variation brightnesses, which are successively sensed, while sensing a variation brightness each time the voltage level of the first potential driving power is reduced, and
wherein the determining whether the variation brightness satisfies the condition includes comparing the brightness change slope with a second value and determining the brightness change slope is equal to or greater than the second value.

2. The method of claim 1 , wherein the reference value of the first potential driving power is in the active region, and
wherein the voltage margin is selected as a minimum value among voltage values that cause the final value of the first potential driving power to fall within the saturation region.

3. The method of claim 1 , further comprising:
sensing a saturation brightness corresponding to the initial value of the first potential driving power,
wherein the determining whether the variation brightness satisfies the condition includes comparing a reduction brightness, which is reduced from the saturation brightness by a first value, with the variation brightness and deciding whether or not the variation brightness is equal to or less than the reduction brightness value.

4. The method of claim 3 , wherein the first value is 1% to 50% of the saturation brightness or 5% to 15% of the saturation brightness.

5. The method of claim 1 , wherein the second value is 1.02 to 1.05.

6. The method of claim 1 , further comprising:
counting and accumulating a driving time; and
deciding whether or not an accumulated count value is equal to or greater than a set value,
wherein each time the accumulated count value is equal to or greater than the set value, sensing changes in driving characteristics of the display panel is performed and determining the final value of the first potential driving power is performed to renew the final value of the first potential driving power.

7. An organic light emitting display comprising:
a display panel including a plurality of pixels, each pixel among the plurality of pixels including an organic light emitting diode (OLED) connected between a first potential driving power having an initial value and a second potential driving power, and a driving thin film transistor (TFT) connected between the first potential driving power and the second potential driving power, wherein the first potential driving power is different than the second potential driving power;
a driver integrated circuit (IC) configured to drive the display panel;
a power IC configured to apply the first potential driving power to the display panel; and
a controller to configured to:
display a test image by the display panel based on a test pattern and sense a brightness of light generated from the test image by a light sensor within the organic light emitting display,
vary a voltage level of the first potential driving power and sense a variation brightness of the display panel by the light sensor,
determine whether the variation brightness satisfies a condition that includes a change in the brightness of light being less than or equal to a reduction brightness value, set a voltage level of the first potential driving power obtained in response to the variation brightness satisfying the condition, as a reference value of the first potential driving power, and add a voltage margin to the reference value of the first potential driving power to determine a final value of the first potential driving power, and
drive the display panel by applying the final value of the first potential driving power to the display panel,
wherein the condition indicates that the variation brightness exists in an active region in a driving thin film transistor (TFT) drain-source voltage (Vds)-drain-source current (Ids) plane of a display panel driving operation, and the final value of the first potential driving power is less than the initial value of the first potential driving power in a saturation region in the driving TFT Vds-Ids plane of the display panel driving operation following the active region,
wherein the controller is further configured to vary the voltage level of the first potential driving power and sense variation brightness of the display panel by stepwise reducing the voltage level of the first potential driving power and calculating a brightness change slope between variation brightnesses, which are successively sensed, while sensing a variation brightness each time the voltage level of the first potential driving power is reduced, and
wherein the controller is further configured to determine whether the variation brightness satisfies the condition by comparing the brightness change slope with a second value and determining the brightness change slope is equal to or greater than the second value.

8. The organic light emitting display of claim 7 , wherein the reference value of the first potential driving power is in the active region, and
wherein the voltage margin is selected as a minimum value among voltage values, that cause the final value of the first potential driving power to fall within the saturation region.

9. The organic light emitting display of claim 7 , wherein the controller is further configured to:
sense a saturation brightness corresponding to the initial value of the first potential driving power, and
determine whether the variation brightness satisfies the condition by comparing a reduction brightness, which is reduced from the saturation brightness by a first value, with the variation brightness and decide whether or not the variation brightness is equal to or less than the reduction brightness value.

10. The organic light emitting display of claim 9 , wherein the first

Assignees

• Lg Display Co Ltd

Inventors

• Lee Hyunjae
• Park Taeyoung
• Choi Dongjun
• Shim Dongsup
• Kwon Ohgun

Classifications

• G09G2360/141

  the light conveying information used for selecting or modulating the light emitting or modulating element · CPC title

• G09G2320/0693

  Calibration of display systems · CPC title

• G09G2330/021

  Power management, e.g. power saving · CPC title

• G09G2320/048

  using evaluation of the usage time · CPC title

• G09G2360/145

  the light originating from the display screen · CPC title