SYSTEM AND METHODS FOR AGING COMPENSATION IN AMOLED DISPLAYS

• US 20130235023A1
• Filed: 04/24/2013
• Published: 09/12/2013
• 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
• Granted Patent: US 9,384,698 B2
• Time in Patent Office: Days
• US Class Current: 345/212
• 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 allowing measurement of effects on pixels in the panel, comprising:

a plurality of active pixels to display an image under an operating condition, the active pixels each being coupled to a supply line and a programming line;

a plurality of reference pixels included in the display area and coupled to said supply line and said programming line, the reference pixels being controlled so that they are not subject to substantial changes due to aging and operating conditions over time; and

a readout circuit coupled to said active pixels and said reference pixels for reading at least one of current, voltage and charge from said pixels when said pixels are supplied with known input signals, said readout circuit being subject to changes due to aging and operating conditions over time, and the readout values from said active pixels being adjusted using the readout values from said reference pixels.

2. The system of claim 1, wherein said operating conditions include temperature.

3. The system of claim 1, wherein the effect of a global phenomenon, that affects both said active pixels and said reference pixels, is determined from said reference pixels, and then subtracted from the readout values from said reference pixels.

4. The system of claim 3, wherein said effect of a global phenomenon is determined by averaging the readout values from said reference pixels.

5. The system of claim 3, wherein said effect of a global phenomenon is determined by averaging the readout values from a set of master pixels within said reference pixels.