System and methods for aging compensation in AMOLED displays

• US 9,384,698 B2
• Filed: 04/24/2013
• Issued: 07/05/2016
• Est. Priority Date: 11/30/2009
• Status: Active Grant

• Current Assignee: IGNIS Innovation Incorporated
• Original Assignee: IGNIS Innovation Incorporated
• Inventors: Chaji, Gholamreza, Dionne, Joseph Marcel, Azizi, Yaser, Jaffari, Javid, Hormati, Abbas, Liu, Tong, Alexander, Stefan
• Primary Examiner(s): Henson, Mischita
• Assistant Examiner(s): Liao, Christine
• Application Number:
  US13/869,399
• Publication Number:
  US 20130235023A1
• Time in Patent Office: 1,168 Days
• Field of Search: 702/58
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• 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 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 3/006 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 Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• 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 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.

Claims

1. A voltage-programmed display panel having a display area containing multiple pixels and allowing measurement of effects on pixels in the panel, comprising:

a plurality of normal pixels to display an image under an operating condition, the normal pixels each being coupled to a supply line and a programming line for displaying images under said operating condition;

a plurality of reference pixels included in the display area and coupled to said supply line and said programming line, the reference pixels being coupled to said supply line and said programming line in a manner that said reference pixels are controlled so that they are subject only to global effects on said display panel over time;

a readout circuit coupled to said normal pixels and said reference pixels for reading at least one of current, voltage and charge from said normal and reference pixels when said normal and reference pixels are supplied with known input signals; and

a controller coupled to each of said plurality of reference pixels and configured to

measure data from said normal pixels and said reference pixels,

correct the measured data from the reference pixels by subtracting the effect of global effects 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 the signals supplied to said normal pixels on said programming line, based on said trimmed data.

2. The system of claim 1, wherein said global effects include temperature.

3. The system of claim 1, wherein said effects affect both said active normal pixels and said reference pixels.

4. The voltage-programmed display panel of claim 1 in which said effect of global effects is determined by averaging the values of at least a selected group of said reference pixels.