System and methods for extracting correlation curves for an organic light emitting device

• US 10,089,921 B2
• Filed: 01/06/2015
• Issued: 10/02/2018
• Est. Priority Date: 02/04/2010
• Status: Active Grant

• Current Assignee: IGNIS Innovation Incorporated
• Original Assignee: IGNIS Innovation Incorporated
• Inventors: Chaji, Gholamreza, Ngan, Ricky Yik Hei, Zahirovic, Nino
• Primary Examiner(s): Natalini, Jeff
• Application Number:
  US14/590,105
• Publication Number:
  US 20150103106A1
• Time in Patent Office: 1,365 Days
• Field of Search: 345 82, 324403-414
• CPC Class Codes: G09G 2300/0413 Details of dummy pixels or dummy lines in flat panels
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements

Abstract

A system for equalizing the pixels in an array of pixels that include semiconductor devices that age differently under different ambient and stress conditions. The system extracts at least one pixel parameter from the array; creates a stress pattern for the array, based on the extracted pixel parameter; stresses the pixels in accordance with the stress pattern; extracts the pixel parameter from the stressed pixels; determines whether the pixel parameter extracted from the stressed pixels is within a preselected range and, when the answer is negative, creates a second stress pattern for the array, based on the pixel parameter extracted from the stressed pixels, stresses the pixels in accordance with the second stress pattern, extracts the pixel parameter from the stressed pixels, and determines whether the pixel parameter extracted from the stressed pixels is within the preselected range.

Claims

1. A method of equalizing the pixels in an array of pixels that include semiconductor devices that age differently under different ambient and stress conditions, said method comprising

extracting at least one pixel parameter from said array using at least one of a voltage sensor, a current sensor, and a photo sensor;

creating a stress pattern for said array, based on the extracted pixel parameter using a controller;

stressing said pixels in accordance with said stress pattern using a current supply connected to the controller and the array of pixels;

extracting said pixel parameter from the stressed pixels using at least one of the voltage sensor, the current sensor, and the photo sensor;

in response to determining the pixel parameter extracted from the stressed pixels is not within a preselected range, using the controller for;

a) creating an additional stress pattern for said array, based on the pixel parameter extracted from the stressed pixels;

b) stressing said pixels in accordance with said additional stress pattern using the current supply;

c) extracting said pixel parameter from the stressed pixels using at least one of the voltage sensor, the current sensor, and the photo sensor;

d) determining when the pixel parameter extracted from the stressed pixels is within said preselected range; and

e) until the pixel parameter extracted from the stressed pixels is within said preselected range repeat steps a), b), c), d) and e); and

in response to the pixel parameter being within said preselected range returning said array of pixels to normal operation.

2. The method according to claim 1, further comprising a current supply and readout circuit for applying stress to said pixels.

3. A method of equalizing the pixels in an array of pixels that include semiconductor devices that age differently under different ambient and stress conditions, said method comprising

creating a stress history of said pixels during a usage cycle using a controller;

extracting at least one pixel parameter from said array after the usage cycle using at least one of a voltage sensor, a current sensor, and a photo sensor;

creating a stress pattern for said array using the controller, based on the extracted pixel parameter;

stressing said pixels in accordance with said stress pattern using a current supply connected to the controller and the array of pixels;

extracting said pixel parameter from the stressed pixels using at least one of the voltage sensor, the current sensor, and the photo sensor;

in response to determining the pixel parameter extracted from the stressed pixels is not within a preselected range, using the controller for;

a) creating an additional stress pattern for said array, based on the pixel parameter extracted from the stressed pixels;

b) stressing said pixels in accordance with said additional stress pattern using the current supply;

c) extracting said pixel parameter from the stressed pixels using at least one of the voltage sensor, the current sensor, and the photo sensor;

d) determining when the pixel parameter extracted from the stressed pixels is within said preselected range; and

e) until the pixel parameter extracted from the stressed pixels is within said preselected range repeat steps a), b), c), d) and e); and

in response to the pixel parameter being within said preselected range returning said array of pixels to normal operation.

4. The method according to claim 3, further comprising a current supply and readout circuit for applying stress to said pixels.

5. A system for equalizing the pixels in an array of pixels, said system comprising:

the array of pixels comprising a plurality of active pixels for displaying an image, the active pixels each including semiconductor devices that age differently under different ambient and stress conditions,

a controller coupled to said array of pixels and configured to;

control extraction of at least one pixel parameter from said array;

create a stress pattern for said array, based on the extracted pixel parameter;

control application of stress to said pixels in accordance with said stress pattern;

control extraction of said pixel parameter from the stressed pixels;

determine whether the pixel parameter extracted from the stressed pixels is within a preselected range and, when the answer is negative;

a) create an additional stress pattern for said array, based on the pixel parameter extracted from the stressed pixels;

b) control application of stress to said pixels in accordance with said additional stress pattern;

c) control extraction of said pixel parameter from the stressed pixels;

d) determine whether the pixel parameter extracted from the stressed pixels is within said preselected range; and

e) until the pixel parameter extracted from the stressed pixels is within said preselected range repeat steps a), b), c), d) and e); and

when the pixel parameter is within said preselected range, said array of pixels is returned to normal operation.

6. The system according to claim 5, wherein the at least one pixel parameter comprise a threshold voltage of a drive thin film transistor (TFT) in each active pixel;

and

further comprising a voltage sensor for extraction of the threshold voltage.

7. The system according to claim 5, wherein the at least one pixel parameter comprises luminance level;

and

further comprising at least one photo sensor for extraction of the luminance level of each pixel.

8. The system according to claim 5, wherein the at least one pixel parameter comprises current output of pixel;

and

further comprising at least one current sensor for extraction of the current output.

9. The system according to claim 5, further comprising a current supply and readout circuit for applying stress to said pixels.

10. A system for equalizing the pixels in an array of pixels, said system comprising:

the array of pixels comprising a plurality of active pixels for displaying an image, the active pixels each including semiconductor devices that age differently under different ambient and stress conditions,

a controller coupled to said array of pixels and configured to;

create a stress history of said pixels during a usage cycle;

control extraction of at least one pixel parameter from said array;

create a stress pattern for said array, based on the extracted pixel parameter;

control application of stress to said pixels in accordance with said stress pattern;

control extraction of said pixel parameter from the stressed pixels;

determine whether the pixel parameter extracted from the stressed pixels is within a preselected range and, when the answer is negative;

a) create an additional stress pattern for said array, based on the pixel parameter extracted from the stressed pixels;

b) control application of stress to said pixels in accordance with said additional stress pattern;

c) control extraction of said pixel parameter from the stressed pixels;

d) determine whether the pixel parameter extracted from the stressed pixels is within said preselected range; and

e) until the pixel parameter extracted from the stressed pixels is within said preselected range repeat steps a), b), c), d) and e); and

when the pixel parameter is within said preselected range, said array of pixels is returned to normal operation.

11. The system according to claim 10, wherein the at least one pixel parameter comprise threshold voltage of a drive thin film transistor (TFT) in each active pixel;

and

further comprising a voltage sensor for extraction of the threshold voltage.

12. The system according to claim 10, wherein the at least one pixel parameter comprises luminance level;

and

further comprising at least one photo sensor for extraction of the luminance level of each pixel.

13. The system according to claim 10, wherein the at least one pixel parameter comprises current output of pixel;

and

further comprising at least one current sensor for extraction of the current output.

14. The system according to claim 10, further comprising a current supply and readout circuit for applying stress to said pixels.