Display system

Patent metadata

Field	Value
Publication number	US-10997901-B2
Application number	US-201514630906-A
Country	US
Kind code	B2
Filing date	Feb 25, 2015
Priority date	Feb 28, 2014
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A method of recovering a display having a plurality of pixels, each having a light emitting device and a driving transistor for driving the light emitting device. The driving transistor and the light emitting device are coupled in series between a first power supply and a second power supply. The method illuminates the semiconductor device while negatively biasing the pixel circuit with a recovery voltage different from an image programming voltage. The illuminating may follow a first cycle implementing an image display operation that includes programming the pixel circuit for a valid image and driving the pixel circuit to emit light according to the programming.

First claim

The invention claimed is:

1. A method of recovering a display having a plurality of pixels, each having a light emitting device and a driving transistor for driving the light emitting device, the driving transistor and the light emitting device being coupled in series between a first power supply and a second power supply, the method comprising:
illuminating the driving transistor of each pixel of the plurality of pixels while independently negatively biasing the driving transistor of each pixel using a respective recovery voltage different from an image programming voltage, a respective magnitude of negative biasing provided by said respective recovery voltage for each pixel being based specifically on a respective signal representing a performance of said pixel, said respective recovery voltage to reduce non-uniformity of the plurality of pixels including both initial non-uniformities and non-uniformities caused by aging, said illuminating the driving transistor while negatively biasing the driving transistor with the respective recovery voltage producing a negative induced VT voltage shift in the driving transistor; and
following said negative induced VT shift in the driving transistor, driving the driving transistor based on said respective signal representing a performance of said pixel to induce a positive VT shift determined to minimize gaps in performances of different pixel circuits.

2. The method of claim 1 in which the illumination is with light in the blue or ultraviolet range.

3. The method of claim 1 in which the negative induced VT shift and the positive induced VT shift are repeated multiple times.

4. The method of claim 1 in which the illumination is generated by said light emitting device of each pixel.

5. The method of claim 1 in which the respective signal representing the performance of the pixel represents a current level for a given voltage or a voltage level for a given current.

6. The method of claim 5 in which non-uniformities associated with the plurality of pixels including both initial non-uniformities and non-uniformities caused by aging are reduced by using different respective recovery voltages to bias the driving transistor of each pixel.

7. The method of claim 1 in which the illumination and the recovery voltage are substantially constant.

8. The method of claim 1 in which the illumination and the recovery voltage are pulses.

9. A method for a display including a plurality of pixel circuits, each having a light emitting device and a driving transistor for driving the light emitting device, the method comprising:
during a first cycle, implementing an image display operation including programming each pixel circuit for a valid image and driving the pixel circuit to emit light according to the programming;
during a second cycle, implementing a recovery operation for recovering a portion of the display, the recovery operation including illuminating the driving transistor of each pixel circuit while independently negatively biasing the driving transistor of each pixel using a respective recovery voltage different from an image programming voltage for a valid image, a respective magnitude of negative biasing provided by said respective recovery voltage for each pixel being based specifically on a respective signal representing a performance of said pixel, said respective recovery voltage to reduce non-uniformity of the plurality of pixels including both initial non-uniformities and non-uniformities caused by aging, said illuminating the driving transistor while negatively biasing the driving transistor with the respective recovery voltage producing a negative induced VT voltage shift in the driving transistor; and
following said negative induced VT shift in the driving transistor, driving the driving transistor based on said respective signal representing a performance of said pixel to induce a positive VT shift determined to minimize gaps in performances of different pixel circuits.

10. The method of claim 9 in which the illumination is with light in the blue or ultraviolet range.

11. The method of claim 9 in which the negative induced VT shift and the positive induced VT shift are repeated multiple times.

12. The method of claim 9 in which the illumination is generated by said light emitting device of the pixel circuit.

13. The method of claim 9 in which the respective signal representing the performance of the pixel represents a current level for a given voltage or a voltage level for a given current.

14. The method of claim 13 in which non-uniformities associated with the plurality of pixels including both initial non-uniformities and non-uniformities caused by aging are reduced by using different respective recovery voltages to bias the driving transistor of each pixel circuit.

15. The method of claim 9 in which the illumination and the recovery voltage are substantially constant.

16. The method of claim 9 in which the illumination and the recovery voltage are pulses.

Assignees

• Ignis Innovation Inc

Inventors

• Nathan Arokia
• Chaji Gholamreza
• Dionne Joseph Marcel

Classifications

• 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

• G09G3/3291

  in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements · CPC title

• G09G2320/048

  using evaluation of the usage time · CPC title