COLLISION AVOIDANCE SCHEMES FOR DISPLAYS

• US 20190027114A1
• Filed: 09/27/2017
• Published: 01/24/2019
• Est. Priority Date: 07/20/2017
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Chu, Yue Jack, Tann, Christopher P., Spence, Arthur L., Simeral, Brad W., Bi, Yafei, Jin, Jiayi, Huang, Ruo-Gu, Li, Haifeng, Yao, Weijun, Wang, Chaohao
• Granted Patent: US 10,825,419 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G06T 1/60 Memory management
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2330/022 in absence of operation, e.g. no data being entered during a predetermined time
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 2370/10 Use of a protocol of communication by packets in interfaces along the display data pipeline
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: G09G 5/363 Graphics controllers
• CPC Class Codes: G09G 5/395 Arrangements specially adapted for transferring the contents of the bit-mapped memory to the screen G09G5/399 takes precedence

Abstract

In situations with reduced image changes, display panels, such as the ones disclosed herein, may reduce their power consumption by performing self-refresh cycles, in which they may display locally stored data in the display panel instead of retrieving it from an image buffer. Methods and circuitry for management of the self-refresh cycle may reduce jitter, luminance errors, and/or flickers that may be caused by untimely self-refresh cycles that may occur as a result of latency in the image buffer. In some implementations, the display panel may have a dedicated low latency input that notifies an arrival of an incoming image. In some implementations, the self-refresh cycles of the panel may be managed by a host or a buffer that is responsible for sending the images.

Claims

1. A system comprising:

a host configured to provide image data and a content warning signal;

a frame buffer configured to receive the image data; and

a panel configured to;

receive the content warning signal;

perform a self-refresh cycle based on an image timeout, wherein the self-refresh cycle comprises displaying a previous image when the image data in the frame buffer does not change; and

wait for a new image data instead of performing the self-refresh cycle based on the received content warning signal.

2. The system of claim 1, wherein the frame buffer comprises a first lag, and wherein the content warning signal comprises a second lag that is smaller than the first lag.

3. The system of claim 1, wherein the content warning signal comprises a warning period, and wherein the panel is configured to prevent a self-refresh cycle during the warning period.

4. The system of claim 3, wherein a presentation time of the panel is smaller than a difference between a period of the self-refresh cycle and a duration of the warning period.

5. The system of claim 3, wherein the host is configured to provide a self-refresh command to the panel, wherein the host arbitrates between sending a self-refresh signal or the image data, and wherein the panel is configured to perform a self-refresh cycle upon receiving the self-refresh command.

6. The system of claim 1, wherein the panel comprises a variable display update interval.

7. The system of claim 1, wherein the panel comprises an organic light emitting diode (OLED) panel.

8. The system of claim 1, wherein the host comprises a system on chip.

9. The system of claim 1, wherein the host comprises a central processing unit, a graphic processing unit, or both.

10. A panel comprising:

a driver integrated circuit configured to;

poll a frame buffer for new image data;

if the frame buffer comprises new image data, cause the panel to display an image based on the new image data in the frame buffer;

if the frame buffer does not comprise new image data, poll an image interrupt for an image warning;

if the image warning is not present, cause the panel to display an image stored in a memory of the driver integrated circuit; and

if the image warning is present, wait until the frame buffer comprises new image data corresponding to the image warning by polling the frame buffer for the new image data.

11. The panel of claim 10, wherein the panel comprises a dedicated input that comprises an image interrupt.

12. The panel of claim 10, wherein the panel comprises the frame buffer, and wherein the panel is configured to couple to a host via a connection configured to carry the new image data and the image warning.

13. The panel of claim 10, comprising a variable display update interval.

14. The panel of claim 10, wherein the new image data comprises a target display time, and wherein a difference between the target display time and an actual display time is smaller than max(Tf−

Tw,Ts), wherein Tf corresponds to an image data period, Tw corresponds to an image warning period, and Ts corresponds to an internal timestep of the driver integrated circuit.

15. The panel of claim 10, wherein the panel comprises a frame rate, and wherein the driver integrated circuit is configured to causes the panel to display an image at the frame rate.

16. An electronic device, comprising:

a host configured to;

provide image data to a display; and

provide a self-refresh signal to the display based on a target display time of the image data; and

a display panel driver of the display coupled to the host and configured to;

cause the display to show an image corresponding to the image data following a time interval below a presentation time threshold; and

cause the display to self-refresh, based in part on the self-refresh signal, wherein self-refresh comprises redisplaying an image stored in a frame buffer.

17. The electronic device of claim 16, wherein the display panel driver causes the self-refresh upon receiving the self-refresh signal.

18. The electronic device of claim 17, wherein the display panel driver is coupled to a host via an image data bus that carries the image data and the self-refresh signal.

19. The electronic device of claim 17, wherein providing the self-refresh signal based on the target display time comprises:

determining an estimated display time based on a period of the self-refresh operation;

determining a difference between the target display time and the estimated display; and

providing the self-refresh signal if the difference between the target display time and the estimated time is smaller than a tolerance.

20. The electronic device of claim 19, wherein the display panel driver is coupled to a host via an image data bus that carries the image data and an interrupt line that carries the self-refresh signal.