Adaptive feedback system for compensating for aging pixel areas with enhanced estimation speed

• US 9,978,297 B2
• Filed: 03/22/2017
• Issued: 05/22/2018
• Est. Priority Date: 05/26/2011
• Status: Active Grant

• Current Assignee: IGNIS Innovation Incorporated
• Original Assignee: IGNIS Innovation Incorporated
• Inventors: Jaffari, Javid, Chaji, Gholamreza, Heidari, Abdorreza
• Primary Examiner(s): Polo, Gustavo
• Application Number:
  US15/466,468
• Publication Number:
  US 20170193873A1
• Time in Patent Office: 426 Days
• Field of Search: None
• CPC Class Codes: G09G 2310/0254 Control of polarity reversal in general, other than for liquid crystal displays
• CPC Class Codes: G09G 2310/0256 with the purpose of reversing the voltage across a light emitting or modulating element within a pixel
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• 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 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• 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 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements

Abstract

A local priority-based scanning scheme that focuses scanning to areas of a display panel whose measured characteristics are under continuous change (e.g., aging or relaxation). The algorithm identifies areas or regions needing compensation, using a current measurement from a single pixel in an area as a candidate to determine whether the rest of the region needs further compensation. The algorithm thus detects newly changed areas quickly, focusing time-consuming measurements on those areas that need high attention. Optionally, neighboring pixels sharing the same state (e.g., aging or overcompensated) as the measured pixel can be adjusted automatically given the likelihood that the neighboring pixels will also require compensation if the measured pixel needs compensation.

Claims

1. A method of compensating for adverse phenomena of pixels of a display panel comprising a plurality of areas, each pixel comprising a drive transistor and a light-emitting device, the method comprising:

tracking for each pixel, characteristic data representing at least one characteristic indicative of at least one adverse phenomenon associated with the pixel;

during a frame period, measuring the at least one characteristic of a number of pixels of each area, the number of pixels of each area measured determined to be larger for an area continuously exhibiting the at least one adverse phenomenon than for an area not continuously exhibiting the at least one adverse phenomenon;

updating the characteristic data for the number of pixels of the display based on measurements of the number of pixels of each area; and

compensating for the at least one adverse phenomenon for at least the number of pixels of each area with use of updated characteristic data of the number of pixels of each area.

2. The method of claim 1 wherein the number of pixels comprises a first plurality of pixels, each area of the plurality of areas comprises at least one cluster of pixels, and measuring the at least one characteristic of a number of pixels of each area comprises:

during a first scanning phase, measuring the at least one characteristic for the first plurality of pixels in the at least one cluster of pixels, the number of pixels in the first plurality of pixels determined based on changes in time of the at least one characteristic for each of the first plurality of pixels in the at least one cluster,

wherein updating the characteristic data for the number of pixels of each area comprises updating the characteristic data for the first plurality of pixels of each area based on measurements of the first plurality of pixels of each area and wherein compensating for the at least one adverse phenomenon for at least the number of pixels of each area comprises compensating for the at least one adverse phenomenon for at least the first plurality of pixels of each area with use of updated characteristic data of the first plurality of pixels of each area.

3. The method of claim 2 wherein the number of pixels measured during the first scanning phase when the at least one characteristic of the first plurality of pixels has changed in time is larger than the number of pixels measured during the first scanning phase when the at least one characteristic of the first plurality of pixels has remained constant.

4. The method of claim 2, wherein measuring the at least one characteristic of each pixel comprises determining a state of the at least one characteristic, wherein the characteristic data comprises stored state data of the at least one characteristic of the pixel and absolute deviation data representing an accumulated absolute deviation of the at least one characteristic of the pixel.

5. The method of claim 4, wherein updating the characteristic data for the first plurality of pixels comprises updating the stored state data and the absolute deviation data for the first plurality of pixels.

6. The method of claim 5, wherein the at least one characteristic comprises drive current indicative of aging and drive current indicative of overcompensation, and wherein the at least one adverse phenomenon comprises aging and overcompensation.

7. The method of claim 5 further comprising:

compensating for the at least one adverse phenomenon for pixels of the display for which characteristic data is stored with use of the absolute deviation data stored for those pixels.

8. The method of claim 5, wherein the at least one characteristic comprises at least one of drive-current, light-emitting device voltage, pixel brightness, and colour intensity.

9. The method of claim 8, wherein the at least one adverse phenomenon comprises at least one of aging, compensation, temperature variation, and process variation.

10. The method of claim 1 further comprising:

compensating for the at least one adverse phenomenon for at least one pixel neighboring the number of pixels of the display of each area based on measurements of the number of pixels of each area.

11. The method of claim 1 wherein the number of pixels comprises a second plurality of pixels, each area of the plurality of areas comprises at least one cluster of pixels, and measuring the at least one characteristic of a number of pixels of each area comprises:

during a second scanning phase, measuring the at least one characteristic for the second plurality of pixels in the at least one cluster of pixels, the number of pixels in the second plurality of pixels determined based on the at least one characteristic for all of the pixels of a cluster of the at least one cluster,

wherein updating the characteristic data for the number of pixels of each area comprises updating the characteristic data for the second plurality of pixels of each area based on measurements of the second plurality of pixels of each area and wherein compensating for the at least one adverse phenomenon for at least the number of pixels of each area comprises compensating for the at least one adverse phenomenon for at least the second plurality of pixels of each area with use of updated characteristic data of the second plurality of pixels of each area.

12. The method of claim 11, wherein the number of pixels measured during the second scanning phase when a total number of pixels of the cluster that have a state of the at least one characteristic indicative of at least one adverse phenomenon exceeds a total number of pixels of the cluster that have a different state is greater than the number of pixels measured during the second scanning phase when a total number of pixels of the cluster that have a state of the at least one characteristic indicative of at least one adverse phenomenon equals a total number of pixels of the cluster that have a different state.

13. The method of claim 12, wherein measuring the at least one characteristic of each pixel comprises determining a state of the at least one characteristic, wherein the characteristic data comprises stored state data of the at least one characteristic of the pixel and absolute deviation data representing an accumulated absolute deviation of the at least one characteristic of the pixel.

14. The method of claim 13, wherein updating the characteristic data for the second plurality of pixels comprises updating the stored state data and the absolute deviation data for the second plurality of pixels.

15. The method of claim 14, wherein the at least one characteristic comprises drive current indicative of aging and drive current indicative of overcompensation, and wherein the at least one adverse phenomenon comprises aging and overcompensation.

16. The method of claim 14 further comprising:

compensating for the at least one adverse phenomenon for pixels of the display for which characteristic data is stored with use of the absolute deviation data stored for those pixels.

17. The method of claim 14, wherein the at least one characteristic comprises at least one of drive-current, light-emitting device voltage, pixel brightness, and color intensity.

18. The method of claim 17, wherein the at least one adverse phenomenon comprises at least one of aging, compensation, temperature variation, and process variation.