Light-Emitting Diode Displays with Predictive Luminance Compensation

• US 20170076661A1
• Filed: 08/15/2016
• Published: 03/16/2017
• Est. Priority Date: 09/14/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Zhang, Yifan, Drzaic, Paul S., Chen, Wei
• Granted Patent: US 9,997,104 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0413 Details of dummy pixels or dummy lines in flat panels
• 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 2320/041 Temperature compensation
• 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 2320/046 Dealing with screen burn-in prevention or compensation of the effects thereof
• CPC Class Codes: G09G 2320/048 using evaluation of the usage time
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]

Abstract

An electronic device may be provided with a display. A content generator may generate frames of image data to be displayed on the display. The display may have an array of pixels that emit light to display images. The pixels may contain light-emitting devices such as organic light-emitting diodes, quantum dot light-emitting diodes, and light-emitting diodes formed from discrete semiconductor dies. As a result of aging, the light producing capabilities of the light-emitting devices may degrade over time. The electronic device may have a temperature sensor that gathers temperature measurements. A pixel luminance degradation compensator may apply compensation factors to uncorrected pixel luminance values associated with the frames of image data to produce corresponding corrected pixel luminance values for the display. The compensation factors may be based on aging history information such as pixel luminance history and temperature measurements.

Claims

1. An electronic device, comprising:

a display having an array of pixels, each pixel having a respective light-emitting device, wherein the display is contained in a batch of displays having associated display batch characterization information;

control circuitry that displays content on the array of pixels of the display; and

a pixel luminance degradation compensator implemented on the control circuitry that uses the display batch characterization information associated the batch of displays to adjust pixel luminance values for the pixels to compensate for aging-induced pixel luminance degradation in the light-emitting devices.

2. The electronic device defined in claim 1 wherein the array of pixels forms an active area of the display that displays images and wherein the display further comprises an inactive area that contains dummy pixels that emit light that is not part of the images.

3. The electronic device defined in claim 2 wherein the display batch characterization information includes information obtained from the dummy pixels of at least one of the displays in the batch of displays.

4. The electronic device defined in claim 1 wherein the light-emitting devices comprise light-emitting diodes.

5. The electronic device defined in claim 4 further comprising an ambient light sensor that is configured to measure light from at least some of the pixels.

6. The electronic device defined in claim 1 wherein pixel luminance degradation compensator is configured to maintain pixel aging history information for the array of pixels.

7. The electronic device defined in claim 6 wherein the pixel luminance degradation compensator maintains the pixel aging history information at least partly by determining pixel aging factors for the pixels based on the display batch characterization information and wherein the pixel luminance degradation compensator encrypts and decrypts the pixel aging history information.

8. The electronic device defined in claim 7 further comprising a temperature sensor that provides temperature measurements to the pixel luminance degradation compensator, wherein the pixel luminance degradation compensator determines the pixel aging factors based at least partly based on the temperature measurements.

9. The electronic device defined in claim 8 wherein the pixel luminance degradation compensator adjusts the pixel luminance values for the pixels by applying compensation factors to the pixel luminance values and wherein the compensation factors are based at least partly on the pixel aging factors.

10. An electronic device, comprising:

a display having an array of pixels, wherein each of the pixels has a respective light-emitting diode and wherein the display is one of a batch of displays characterized by display batch characterization information; and

control circuitry on which a content generator and a pixel luminance degradation compensator are implemented, wherein the content generator produces image content for the display with uncorrected pixel luminance values and wherein the pixel luminance degradation compensator adjusts the uncorrected pixel luminance values based at least partly on the display batch characterization information to produce corresponding corrected pixel luminance values for the image content.

11. The electronic device defined in claim 10 wherein the pixel luminance degradation compensator produces the corrected pixel luminance values by applying compensation factors to the uncorrected pixel luminance values to compensate for aging-induced pixel luminance degradation in the light-emitting diodes.

12. The electronic device defined in claim 11 wherein the light-emitting diodes comprise organic light-emitting diodes.

13. The electronic device defined in claim 11 wherein the light-emitting diodes comprise quantum dot light-emitting diodes.

14. The electronic device defined in claim 11 wherein the light-emitting diodes comprise discrete crystalline semiconductor dies.

15. The electronic device defined in claim 11 further comprising a temperature sensor that gathers temperature measurements, wherein the pixel luminance degradation compensator produces the compensation factors at least partly based on the temperature measurements.

16. The electronic device defined in claim 11 wherein the pixel luminance degradation compensator produces the compensation factors based on encrypted pixel aging history information maintained in the control circuitry.

17. The electronic device defined in claim 16 wherein the control circuitry includes protected storage that is not disturbed when installing operating system code on the electronic device and wherein the pixel aging history is maintained in the protected storage.

18. An electronic device, comprising:

an organic light-emitting diode display having an array of pixels, wherein the organic light-emitting diode display is one of a batch of displays characterized by display batch characterization information; and

control circuitry on which a content generator and a pixel luminance degradation compensator are implemented, wherein the content generator produces image content for the display with uncorrected pixel luminance values and wherein the pixel luminance degradation compensator adjusts the uncorrected pixel luminance values based at least partly on the display batch characterization information to produce corresponding corrected pixel luminance values for the image content.

19. The electronic device defined in claim 18 wherein the pixel luminance degradation compensator maintains encrypted pixel aging history information in the control circuitry based at least partly on the uncorrected pixel luminance values.

20. The electronic device defined in claim 18 further comprising a temperature sensor that gathers temperature measurements, wherein the pixel luminance degradation compensator maintains pixel aging history information in the control circuitry based at least partly on the uncorrected pixel luminance values and the temperature measurements.