Organic light emitting display and method of driving the same

Patent metadata

Field	Value
Publication number	US-2016012800-A1
Application number	US-201514788392-A
Country	US
Kind code	A1
Filing date	Jun 30, 2015
Priority date	Jul 10, 2014
Publication date	Jan 14, 2016
Grant date	—

Abstract

In one aspect, there is an organic light emitting display comprising: a display panel including subpixels; a data driver that supplies a data signal to the display panel; a scan driver that supplies a scan signal to the display panel; and a sensing circuit unit that measures the threshold voltages of driving transistors through sensor transistors of the display panel and prepares compensation data, wherein the scan driver turns on the sensor transistor of a selected subpixel to measure the threshold voltage of the driving transistor of the selected subpixel during a vertical blank interval of the display panel, and turns on the sensor transistors of non-selected subpixels to supply voltages below the threshold voltage of organic light emitting diodes to the non-selected subpixels during an image display interval of the display panel.

First claim

What is claimed is:

1 . An organic light emitting display comprising:
a display panel including subpixels; a data driver that supplies a plurality of data signals to the display panel; a scan driver that supplies a plurality of scan signals to the display panel; and a sensing circuit unit that measures threshold voltages of driving transistors through sensor transistors of the display panel and prepares compensation data, wherein the scan driver turns on the sensor transistor of selected subpixels to measure the threshold voltages of the driving transistors of the selected subpixels during a vertical blank interval of the display panel, and turns on the sensor transistors of non-selected subpixels to supply voltages below a threshold voltage of organic light emitting diodes to the non-selected subpixels during an image display interval of the display panel.

2 . The organic light emitting display of claim 1 , wherein a charging status at the nodes of the anodes of the organic light emitting diodes of the non-selected subpixels mimic a charging status at the nodes of the anodes of the organic light emitting diodes of selected subpixels during the image display interval of the display panel.

3 . The organic light emitting display of claim 1 , wherein the nodes of the anodes of the organic light emitting diodes of the selected subpixels and the non-selected subpixels are charged during the image display interval of the display panel in such a way that the voltages increase non-linearly toward saturation and then increase non-linearly again toward saturation.

4 . The organic light emitting display of claim 1 , wherein the scan driver sequentially turns on the sensor transistors of the non-selected subpixels during the image display interval of the display panel.

5 . The organic light emitting display of claim 1 , wherein, during the image display interval of the display panel, the non-selected subpixels are arranged into N blocks (N is an integer equal to or greater than 2) and the scan driver turns on the sensor transistors of the non-selected subpixels on a block-by-block basis.

6 . The organic light emitting display of claim 1 , wherein the scan driver varies the pulse width of a scan signal to adjust the turn-on time of the sensor transistors of the non-selected subpixels during the image display interval of the display panel.

7 . The organic light emitting display of claim 1 , wherein the sensing circuit unit senses the threshold voltages of the driving transistors of a line of subpixels on the display panel during the vertical blank interval of the display panel.

8 . The organic light emitting display of claim 1 , wherein, during the vertical blank interval of the display panel, the subpixels are arranged into N blocks (N is an integer equal to or greater than 2) of the display panel and the sensing circuit unit senses the threshold voltage of the driving transistors of the blocks of subpixels.

9 . The organic light emitting display of claim 1 , wherein the sensing circuit unit comprises:
a first circuit portion for converting a voltage of a reference line connected to the subpixels into a pulse voltage; a second circuit portion for outputting the pulse voltage resulting from the conversion by the first circuit portion as a step voltage; a third circuit portion for converting the step voltage output from the second circuit portion to digital format; and a fourth circuit portion for outputting a switching control signal to control switching circuits of the first circuit portion during the vertical blank interval of the display panel.

10 . The organic light emitting display of claim 1 , wherein a voltage pattern at the node between the organic light emitting diode and the driving transistor of each of the non-selected subpixels mimics a voltage pattern at a node between the organic light emitting diode and the driving transistor of each of the selected subpixels.

11 . A method of driving an organic light emitting display, the method comprising:
turning on sensor transistors of selected subpixels to measure threshold voltages of driving transistors of the selected subpixels during a vertical blank interval of a display panel; turning on sensor transistors of non-selected subpixels to supply voltages below a threshold voltage of organic light emitting diodes to the non-selected subpixels during an image display interval of the display panel; and preparing compensation data based on the threshold voltages of the driving transistor and outputting the compensation data.

12 . The method of claim 11 , wherein a charging status at the nodes of the anodes of the organic light emitting diodes of the non-selected subpixels mimic a charging status at the nodes of the anodes of the organic light emitting diodes of the selected subpixels during the image display interval of the display panel.

13 . The method of claim 11 , wherein the nodes of the anodes of the organic light emitting diodes of the selected subpixels and the non-selected subpixels are charged during the image display interval of the display panel in such a way that the voltages increase non-linearly toward saturation and then increase non-linearly again toward saturation.

14 . The method of claim 11 , wherein the sensor transistors of the non-selected subpixels are sequentially turned on during the image display interval of the display panel.

15 . The method of claim 11 , wherein, during the image display interval of the display panel, the non-selected subpixels are divided into N blocks (N is an integer equal to or greater than 2) and turned on block-by-block.

16 . The method of claim 11 , wherein a turn-on time of the sensor transistors of the non-selected subpixels is varied during the image display interval of the display panel.

17 . The method of claim 11 , wherein the threshold voltages of the driving transistors of a line of subpixels on the display panel are sensed during the vertical blank interval of the display panel.

18 . The method of claim 11 , wherein, during the vertical blank interval of the display panel, N lines of subpixels (N is an integer equal to or greater than 2) of the display panel are divided into blocks and the threshold voltages of the driving transistors of the subpixels are sensed.

Assignees

• Lg Display Co Ltd

Inventors

• Han Sungman
• Shim Jongsik

Classifications

• G09G2320/0295

  by monitoring each display pixel · CPC title

• G09G3/3233 Primary

  with pixel circuitry controlling the current through the light-emitting element · CPC title

• G09G2310/0251

  Precharge or discharge of pixel before applying new pixel voltage · CPC title

• G09G2300/0861

  with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes · CPC title

• G09G2320/043

  Preventing or counteracting the effects of ageing · CPC title