Content-Based Adaptive Refresh Schemes For Low-Power Displays

• US 20140104243A1
• Filed: 10/15/2012
• Published: 04/17/2014
• Est. Priority Date: 10/15/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Sakariya, Kapil V., Bibl, Andreas
• Granted Patent: US 9,558,721 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• 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: G09G 2300/026 Video wall, i.e. juxtaposition of a plurality of screens to create a display screen of bigger dimensions
• CPC Class Codes: G09G 2310/0213 controlling the sequence of the scanning lines with respect to the patterns to be displayed, e.g. to save power
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2320/0613 The adjustment depending on the type of the information to be displayed
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2350/00 Solving problems of bandwidth in display systems
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 2370/08 Details of image data interface between the display device controller and the data line driver circuit
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 5/005 Adapting incoming signals to the display format of the display terminal
• CPC Class Codes: G09G 5/399 using two or more bit-mapped memories, the operations of which are switched in time, e.g. ping-pong buffers

Abstract

A content-based adaptive refresh technique is implemented in an active matrix display system for reducing power consumption. The active matrix display system includes a display panel having multiple rows of display elements arranged as a display matrix. The display panel is coupled to a scan driver and a data driver. The scan driver selects one row at a time to receive data signals, and the data driver provides the data signals. The active matrix display system also includes a timing controller operable to signal the scan driver to cause a first row of the display panel to be not refreshed in a current data frame and a second row of the display panel to be refreshed in the current data frame.

Claims

1. An active matrix display system comprising:

a display panel that includes a plurality of rows of display elements arranged as a display matrix;

a scan driver coupled to the display panel to select one of the rows at a time to receive data signals;

a data driver coupled to the display panel to provide the data signals; and

a timing controller coupled to the scan driver and the data driver, the timing controller operable to signal the scan driver to thereby cause a first row of the display panel to be not refreshed in a current data frame and a second row of the display panel to be refreshed in the current data frame.

2. The active matrix display system of claim 1, further comprising:

refresh logic operable to compare content of the first row in the current data frame with content of the first row in a previous data frame to generate a comparison result, and to determine whether the first row is to be refreshed in the current data frame based on the comparison result.

3. The active matrix display system of claim 2, wherein the refresh logic is coupled to the timing controller.

4. The active matrix display system of claim 2, wherein the refresh logic is located within a processor that generating data frames, or on a path between the processor and the display panel.

5. The active matrix display system of claim 2, wherein the refresh logic causes the processor or a hardware component on the path between the processor and the display panel to reduce data transfer rate to the display panel.

6. The active matrix display system of claim 1, wherein the timing controller is operable to signal the scan driver to perform no refresh operation during a line cycle in which the first row was scheduled to be refreshed.

7. The active matrix display system of claim 1, wherein the timing controller is operable to signal the scan driver to refresh the second row instead of the first row during a line cycle in which the first row was scheduled to be refreshed.

8. The active matrix display system of claim 1, wherein the timing controller is operable to signal the scan driver to refresh a first subset of the rows that display a dynamic content at a higher refresh rate than a second subset of the rows that display a static content.

9. The active matrix display system of claim 1, wherein the scan driver is operable to directly address a selected row of the display panel.

10. The active matrix display system of claim 1, wherein the scan driver is operable to directly address selected segments of rows of the display panel, each of the segments being coupled to a different shift register that is used to select a specific row in the segment.

11. The active matrix display system of claim 1, wherein the display panel comprises one of the following:

a plurality of micro light emitting diode (LED) devices of 1 to 100 μ

m scale, a plurality of organic LED (OLED) devices, a plurality of LED devices, or a plurality of liquid crystal display (LCD) devices.

12. A method for refreshing a display panel comprising:

refreshing a first portion of the display panel at a first refresh rate, wherein the first portion displays a static content; and

refreshing a second portion of the display panel at a second refresh rate higher than the first refresh rate, wherein the second portion displays a dynamic content.

13. The method of claim 12, further comprising:

comparing content of the first portion in a current data frame with content of the first portion in a previous data frame to generate a comparison result; and

determining whether the first portion displays a static content based on the comparison result.

14. The method of claim 12, further comprising:

performing no refresh operation during a line cycle in which the first portion was scheduled to be refreshed.

15. The method of claim 12, further comprising:

refreshing the second portion instead of the first portion during a line cycle in which the first portion was scheduled to be refreshed.

16. The method of claim 12, further comprising:

refreshing each portion of the display panel sequentially in a first frame cycle;

refreshing selected portion of the display panel that have content change subsequent to the first frame cycle and before a second frame cycle; and

refreshing each portion of the display panel sequentially in the second frame cycle.

17. The method of claim 12, further comprising:

refreshing each portion of the display panel when the portion of the display panel has a content change beyond a threshold or has reached a time out threshold.

18. The method of claim 12, wherein the display panel comprises a plurality of micro light emitting diode (LED) devices of 1 to 100 μ

m scale, a plurality of organic LED (OLED) devices, a plurality of LED devices, or a plurality of liquid crystal display (LCD) devices.

19. The method of claim 12, wherein the display panel includes a plurality of portions, each portion being a row, a set of rows, a tile, a set of tiles, or a set of LED devices within a tile.

20. An apparatus comprising:

a frame buffer to store a first portion of a current data frame and a corresponding first portion of a previous data frame; and

refresh logic coupled to the frame buffer, the refresh logic operable to compare content of the first portion of the current data frame with content of the corresponding first portion of the previous data frame to generate a comparison result, and to determine whether to refresh the first portion of the current data frame on a display panel based on the comparison result.

21. The apparatus of claim 20, wherein the refresh logic is operable to identify a next portion in the current data frame to be refreshed, and to send an index of the next portion to a controller of the display panel.

22. The apparatus of claim 20, wherein the refresh logic is operable to determine whether a next portion in a sequential order of the current data frame is to be refreshed, and to cause a control signal to be sent to a controller of the display panel to indicate whether refresh of the next portion is activated or ignored.

23. The apparatus of claim 20, wherein the refresh logic is located within a display system coupled to a graphics processing unit (GPU), within a GPU, or within a hardware component coupled between a GPU and a display system.

24. The apparatus of claim 20, wherein the refresh logic is operable to assign different refresh rates to different rows of a display panel.

25. The apparatus of claim 20, wherein the display panel comprises a plurality of micro light emitting diode (LED) devices of 1 to 100 μ

m scale, a plurality of organic LED (OLED) devices, a plurality of LED devices, or a plurality of liquid crystal display (LCD) devices.

26. The apparatus of claim 20, wherein the display panel includes a plurality of portions, and wherein the refresh logic causes each portion of the display panel to be refreshed when the portion has a content change beyond a threshold or has reached a time out threshold.

27. The apparatus of claim 20, wherein the display panel includes a plurality of portions, each portion being a row, a set of rows, a tile, a set of tiles, or a set of LED devices within a tile.