Long-term history of display intensities

Patent metadata

Field	Value
Publication number	US-10453375-B2
Application number	US-201815874791-A
Country	US
Kind code	B2
Filing date	Jan 18, 2018
Priority date	Jun 4, 2017
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

A data processing system can store a long-term history of pixel luminance values in a secure memory and use those values to create burn-in compensation values that are used to mitigate burn-in effect on a display. The long-term history can be updated over time with new, accumulated pixel luminance values.

First claim

What is claimed is:

1. A non-transitory machine readable medium storing executable instructions which when executed by a data processing system cause the data processing system to perform a method comprising:
storing, in memory, a plurality of snapshots over time of data representing display intensity for each pixel in a plurality of pixels in a display, the plurality of pixels displaying one or more images on the display;
accumulating, in an accumulation buffer, the plurality of snapshots to provide an accumulated value for each pixel in the plurality of pixels;
flushing the accumulated value for each pixel in the plurality of pixels from the accumulation buffer to memory in a secure processing system and clearing the accumulated values from the accumulation buffer after the flushing;
adding the accumulated value for each pixel in the plurality of pixels to a long-term history stored in the memory in the secure processing system, the long-term history storing, for each pixel in the plurality of pixels, a long-term display intensity and wherein the secure processing system has one or more private keys and one or more device identifiers, stored in secure memory in the secure processing system, that are not accessible to an application processing system that is coupled to the secure processing system, and wherein the secure processing system verifies code signatures at boot up time of the data processing system and verifies a user to unlock the data processing system from a locked state.

2. The medium as in claim 1 wherein the plurality of pixels in the display includes all of the pixels in the display that are used to display the one or more images.

3. The medium as in claim 1 wherein each of the snapshots has a first number of bits per pixel and each accumulated value has a second number of bits per pixel, the second number being greater than the first number.

4. The medium as in claim 1 wherein the long-term display intensity for each pixel is used to create a compensation value for each pixel to mitigate a burn-in effect on the display.

5. The medium as in claim 4 wherein the burn-in effect dims the maximum brightness of at least some of the pixels.

6. The medium as in claim 1 wherein the long-term history is encrypted by the secure processing system and the encrypted long-term history is stored in non-volatile memory in a file system maintained by an application processing system.

7. The medium as in claim 6 wherein the long-term history, once stored in memory in the secure processing system, is not accessible to the application processing system without authorization from the secure processing system and wherein the secure processing system includes one or more non-extractable device private keys.

8. The medium as in claim 1 wherein the accumulated value for each pixel is stored unencrypted in the accumulation buffer and wherein the plurality of snapshots are stored in DRAM and the accumulation buffer is in DRAM.

9. The medium as in claim 1 wherein the long-term history provides a long-term display intensity for each pixel of the display over the entire lifetime of use of the display, and wherein each of the snapshots is captured and stored once per first time period and wherein the accumulation buffer is flushed once per second time period which is at least 5 times greater than the first time period, and wherein using the accumulation buffer to accumulate a set of snapshots before adding to the long-term history reduces the number of wake ups from sleep or low power state for the secure processing system during the second period of time.

10. The medium as in claim 9 wherein the first time period is less than 5 seconds and the second time period is less than 5 minutes and wherein the snapshots of data include data representing thermal information about the display.

11. A data processing system comprising:
a frame buffer to store image data for display;
a display having a plurality of pixels, the display coupled to the frame buffer;
a first memory to store a plurality of snapshots, taken over time, of data representing display intensity for each pixel in the plurality of pixels;
a second memory to store an accumulation buffer that stores an accumulated value for each pixel in the plurality of pixels, each accumulated value derived by accumulating the display intensities from the plurality of snapshots for the same pixel;
a first processing system coupled to the frame buffer and to the first memory and to the second memory, the first processing system configured to accumulate the display intensities from the plurality of snapshots;
a second processing system coupled to the first processing system, the second processing system including a secure memory, the second processing system to add the accumulated value for each pixel in the plurality of pixels to a long-term history stored in the secure memory after the first processing system is to flush the accumulated value for each pixel in the plurality of pixels, the long-term history storing, for each pixel in the plurality of pixels, a long-term display intensity; and wherein the second processing system is a secure processing system which has one or more private keys and one or more device identifiers, stored in secure memory in the secure processing system, that are not accessible to the second processing system which is an application processing system that is coupled to the secure processing system, and wherein the secure processing system verifies code signatures at boot up time of the data processing system and verifies a user to unlock the data processing system from a locked state.

12. The data processing system as in claim 11 , wherein the plurality of pixels in the display includes all of the pixels in the display that are used to display one or more images on the display.

13. The data processing system as in claim 11 wherein each of the snapshots has a first number of bits per pixel allocated for each snapshot and each accumulated value has a second number of bits per pixel allocated, and the second number is greater than the first number.

14. The data processing system as in claim 11 wherein the long-term display intensity for each pixel is used to create a compensation value for each pixel to mitigate a burn-in effect on the display and wherein the burn-in effect dims the maximum brightness of a least some pixels.

15. The data processing system as in claim 11 wherein the long-term history is encrypted by the second processing system which is a secure processing system and the encrypted long-term history is stored in non-volatile memory in a file system maintained by the first processing system which is an application processing system.

16. The data processing system as in claim 15 wherein the long-term history, once stored in memory in the secure processing system, is not accessible to the application processing system without authorization from the secure processing system.

17. The system as in claim 11 wherein the long-term history provides a long-term display intensity for each pixel of the display over the entire lifetime of use of the display, and wherein each of the snapshots is captured and stored once per first time period and wherein the accumulation buffer is flushed once per second time period which is at least 5 times greater than the first time period, and wherein using the accumulation buffer to accumulate a set of snapshots before adding to the long-term history reduces the number of wake ups from sleep or low power state for the second processing system during the second period of time.

Assignees

• Apple Inc

Inventors

• Drzaic Paul S
• Koh Tae-Wook
• Thompson Ross
• Cote Guy
• Tann Christopher P
• Hauck Jerrold V
• Zhang Yifan
• Guillou Jean-Pierre
• Hendry Ian C
• Heppolette Vanessa C
• Spence Arthur L

Classifications

• G09G2358/00

  Arrangements for display data security · CPC title

• G09G2320/0233

  Improving the luminance or brightness uniformity across the screen · CPC title

• G06F3/067

  Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS] · CPC title

• G06F3/0673

  Single storage device · CPC title

• G09G3/32

  semiconductive, e.g. using light-emitting diodes [LED] · CPC title