Light-emitting diode displays with predictive luminance compensation

Patent metadata

Field	Value
Publication number	US-10163388-B2
Application number	US-201514936343-A
Country	US
Kind code	B2
Filing date	Nov 9, 2015
Priority date	Sep 14, 2015
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

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.

First claim

What is claimed is:

1. An electronic device, comprising:
a display having an array of pixels, each pixel having a respective light-emitting device, wherein the light-emitting devices comprise light-emitting diodes, and wherein the light-emitting diodes comprise crystalline semiconductor dies;
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 adjusts uncorrected pixel luminance values for the pixels to compensate for aging-induced pixel luminance degradation in the light-emitting devices, wherein the pixel luminance degradation compensator is configured to update pixel aging history information for the array of pixels at a first frequency and to determine compensation factors for adjusting the pixel luminance values at a second frequency that is different than the first frequency, and wherein the pixel luminance degradation compensator is further configured to:
determine aging factors directly from the uncorrected pixel luminance values, wherein the aging factors represent how much one of the pixels of the array of pixels or a block of pixels of the array of pixels has aged during operation of the display;
update the pixel aging history information based on the aging factors; and
determine compensation factors based on the updated pixel aging history information using age-induced-luminance-degradation functions, wherein the pixel luminance degradation compensator adjusts the uncorrected pixel luminance values using the compensation factors to generate corrected pixel luminance values, wherein the corrected pixel luminance values are a product of the compensation factors and the uncorrected pixel luminance values.

2. The electronic device defined in claim 1 further comprising a temperature sensor that provides temperature measurements to the pixel luminance degradation compensator, wherein the pixel luminance degradation compensator determines the aging factors based at least partly on the temperature measurements.

3. An electronic device, comprising:
a display having an array of pixels, wherein each of the pixels has a respective light-emitting diode; and
control circuitry on which a content generator and a pixel luminance degradation compensator are implemented, wherein the pixel luminance degradation compensator is coupled between the content generator and the array of pixels, wherein the content generator produces image content for the display with uncorrected pixel luminance values, and wherein the pixel luminance degradation compensator is configured to:
determine aging factors based on the uncorrected pixel luminance values, wherein the aging factors represent how much one of the pixels of the array of pixels or a block of pixels of the array of pixels has aged during operation of the display;
update aging history values based on the aging factors;
calculate compensation factors using nonlinear aged-induced-luminance-degradation functions based on the updated aging history values; and
compute corrected pixel luminance values from the uncorrected pixel luminance values and the compensation factors, wherein the corrected pixel luminance values are a product of the uncorrected pixel luminance values and the compensation factors, wherein the control circuitry includes protected storage that is not disturbed when installing operating system code on the electronic device, and wherein the aging history values are maintained in the protected storage.

4. The electronic device defined in claim 3 wherein the light-emitting diodes comprise organic light-emitting diodes.

5. The electronic device defined in claim 3 wherein the light-emitting diodes comprise quantum dot light-emitting diodes.

6. The electronic device defined in claim 3 wherein the light-emitting diodes comprise discrete crystalline semiconductor dies.

7. The electronic device defined in claim 3 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.

8. An electronic device, comprising:
an organic light-emitting diode display having an array of pixels, wherein the array of pixels comprises a plurality of discrete crystalline semiconductor dies; 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:
determines aging factors based on the uncorrected pixel luminance values, wherein the aging factors are non-linearly dependent on the uncorrected pixel luminance values and wherein the aging factors represent how much one of the pixels of the array of pixels or a block of pixels of the array of pixels has aged during operation of the organic light-emitting diode display;
updates pixel aging history information based on the aging factors;
determines compensation factors based on the updated pixel aging history information using nonlinear age-induced-luminance-degradation functions; and
computes corrected pixel luminance values by multiplying the compensation factors with the uncorrected pixel luminance values, wherein the control circuitry comprises protected storage that is not disturbed when installing operating system code on the electronic device, and wherein the pixel aging history information is maintained in the protected storage.

9. The electronic device defined in claim 8 further comprising a temperature sensor that gathers temperature measurements, wherein the pixel luminance degradation compensator maintains the pixel aging history information in the control circuitry based at least partly on the temperature measurements.

Assignees

• Apple Inc

Inventors

• Zhang Yifan
• Drzaic Paul S
• Chen Chieh-Wei
• Guillou Jean-Pierre S
• Aflatooni Koorosh

Classifications

• G09G2320/0666

  for control of colour parameters, e.g. colour temperature · CPC title

• G09G2320/043

  Preventing or counteracting the effects of ageing · CPC title

• G09G3/2003 Primary

  Display of colours (specific for liquid crystal displays G09G3/3607) · CPC title

• G09G3/3208 Primary

  organic, e.g. using organic light-emitting diodes [OLED] · CPC title

• G09G3/3225

  using an active matrix · CPC title