System and methods for aging compensation in AMOLED displays

Patent metadata

Field	Value
Publication number	US-11580913-B2
Application number	US-202117241389-A
Country	US
Kind code	B2
Filing date	Apr 27, 2021
Priority date	Nov 30, 2009
Publication date	Feb 14, 2023
Grant date	Feb 14, 2023

Abstract

A voltage-programmed display system allows measurement of effects on pixels in a panel that includes both active pixels and reference pixels coupled to a supply line and a programming line. The reference pixels are controlled so that they are not subject to substantial changes due to aging and operating conditions over time. A readout circuit is coupled to the active pixels and the reference pixels for reading at least one of current, voltage or charge from the pixels when they are supplied with known input signals. The readout circuit is subject to changes due to aging and operating conditions over time, but the readout values from the reference pixels are used to adjust the readout values from the active pixels to compensate for the unwanted effects.

First claim

What is claimed is:

1. A display system comprising:
a plurality of normal pixels for displaying an image under an image display operating condition;
a plurality of reference pixels;
a readout circuit coupled to the normal pixels and the reference pixels for measured data from the normal and reference pixels; and
a controller coupled to each reference pixel and each normal pixel and configured to:
control the reference pixels so that they are not subject to the image display operating condition;
correct the measured data from the reference pixels by subtracting an effect common to the normal pixels and the reference pixels from the data measured from the reference pixels;
trim the data measured from the normal pixels with the corrected data read from the reference pixels; and
compensate images displayed on the display system with use of the trimmed data.

2. The display system of claim 1 , wherein the effect common to the normal pixels and the reference pixels comprise temperature effects.

3. The display system of claim 1 , wherein the controller is configured to control the reference pixels such that they are substantially immune to aging.

4. The display system of claim 1 , wherein the effect common to the normal pixels and the reference pixels is determined for each reference pixel with use of measured data from at least one other reference pixel.

5. The display system of claim 1 , wherein the effect common to the normal pixels and the reference pixels is determined with use of an average of the measured data from at least a selected group of the reference pixels.

6. The display system claim 1 , wherein the controller is configured to trim the data from each normal pixel with the corrected data read from one or more reference pixels in the same column as the normal pixel.

7. A display system comprising:
a plurality of normal pixels for display an image under an operating condition;
a plurality of reference pixels controlled so that they are not subject to the operating condition; and
a controller coupled to each reference pixel and each normal pixel and configured to:
supply the normal and reference pixels with known input signals and measure data from the normal and reference pixels;
correct the measured data from the reference pixels by subtracting an effect common to the normal pixels and the reference pixels from the data measured from the reference pixels,
trim the data measured from the normal pixels with the corrected data read from the reference pixels, and
compensate images displayed on the display system with use of the trimmed data.

8. The display system of claim 7 , wherein the effect common to the normal pixels and the reference pixels comprise temperature effects.

9. The display system of claim 7 , wherein the controller is configured to control the reference pixels such that they are substantially immune to aging.

10. The display system of claim 7 , wherein the effect common to the normal pixels and the reference pixels is determined for each reference pixel with use of measured data from at least one other reference pixel.

11. The display system of claim 7 , wherein the effect common to the normal pixels and the reference pixels is determined with use of an average of the measured data from at least a selected group of the reference pixels.

12. The display system of claim 7 , wherein the controller is configured to trim the data from each normal pixel with the corrected data read from one or more reference pixels in the same column as the normal pixel.

13. A method of image compensation for a display system, the display system comprising normal pixels and reference pixels, the method comprising:
operating the normal pixels under an image display operating condition;
operating the reference pixels in a manner that the reference pixels are not subject to the image display operating condition; and
subsequent to the operating of the normal pixels and the operating of the reference pixels:
measuring data from the normal pixels and the reference pixels;
correcting the measured data from the reference pixels by subtracting an effect common to the normal pixels and the reference pixels from the data measured from the reference pixels;
trimming the data measured from the normal pixels with the corrected data read from the reference pixels; and
compensating images displayed on the display system with use of the trimmed data.

14. The method of claim 13 , wherein the effect common to the normal pixels and the reference pixels comprise temperature effects.

15. The method of claim 13 , wherein the reference pixels are operated such that they are substantially immune to aging.

16. The method of claim 13 , further comprising:
determining the effect common to the normal pixels and the reference pixels for each reference pixel with use of measured data from at least one other reference pixel.

17. The method of claim 13 , further comprising:
determining the effect common to the normal pixels and the reference pixels with use of an average of the measured data from at least a selected group of the reference pixels.

18. The method of claim 13 , wherein trimming the data measured from the normal pixels comprises, trimming the data from each normal pixel with the corrected data read from one or more reference pixels in the same column as the normal pixel.

Assignees

• Ignis Innovation Inc

Inventors

• Chaji Gholamreza
• Dionne Joseph Marcel
• Azizi Yaser
• Jaffari Javid
• Hormati Abbas
• Liu Tong
• Alexander Stefan

Classifications

• G09G2320/045

  Compensation of drifts in the characteristics of light emitting or modulating elements · CPC title

• G09G3/006 Primary

  Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays (testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309) · CPC title

• G09G2300/0842

  forming a memory circuit, e.g. a dynamic memory with one capacitor · CPC title

• G09G2320/043

  Preventing or counteracting the effects of ageing · CPC title

• G09G3/3233

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