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

• US 9,640,112 B2
• Filed: 09/12/2016
• Issued: 05/02/2017
• 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 D
• Application Number:
  US15/262,266
• Publication Number:
  US 20160379563A1
• Time in Patent Office: 232 Days
• Field of Search: 345690
• 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, each pixel comprising a drive transistor and a light-emitting device, the method comprising:

storing for each pixel in at least one cluster of pixels, characteristic data representing at least one characteristic indicative of at least one adverse phenomenon associated with the pixel;

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

measuring said at least one characteristic for a second plurality of pixels of said at least one cluster of pixels, a second number of pixels in said 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; and

updating said characteristic data for the first plurality of pixels based on measurements of said first plurality of pixels; and

updating said characteristic data for the second plurality of pixels based on measurements of said second plurality of pixels;

compensating for the at least one adverse phenomenon for at least the first and second plurality of pixels with use of updated characteristic data of said first and second plurality of pixels.

2. The method of claim 1, wherein the first number of pixels determined when the at least one characteristic of the first plurality of pixels of said at least one cluster of pixels has changed in time is less than the first number of pixels determined when the at least one characteristic of the first plurality of pixels of said at least one cluster of pixels has remained constant.

3. The method of claim 1, wherein the second number of pixels determined 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 second number of pixels determined 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.

4. The method of claim 1, wherein measuring said at least one characteristic of a pixel comprises determining a state of said 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 said characteristic data for the first plurality of pixels based on measurements of said first plurality of pixels comprises updating said stored state data and said absolute deviation data for said first plurality of pixels, and wherein updating said characteristic data for the second plurality of pixels based on measurements of said second plurality of pixels comprises updating said stored state data and said absolute deviation data for said second plurality of pixels.

6. The method of claim 5, wherein the first number of pixels determined when the stored state data of the first plurality of pixels of said at least one cluster of pixels has changed in time is less than the first number of pixels determined when the stored state data of the first plurality of pixels of said at least one cluster of pixels has not changed in time, and wherein the second number of pixels determined when a total number of pixels of the cluster that have stored state data indicative of at least one adverse phenomenon exceeds a total number of pixels of the cluster that have different stored state data is greater than the second number of pixels determined when a total number of pixels of the cluster that have stored state data indicative of at least one adverse phenomenon equals a total number of pixels of the cluster that have different stored state data.

7. The method of claim 6 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 6, 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 7, 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.