Concurrently refreshing multiple areas of a display device using multiple different refresh rates
This application relates to methods and apparatus for refreshing a display device at various frequencies. Specifically, multiple areas of the display device can be refreshed concurrently at different frequencies. In this way, when static content is being displayed in certain areas of the display device, those certain areas can be refreshed at a lower rate than areas displaying dynamic content such as video or animation. By refreshing at lower rates, the energy consumed by the display device and subsystems associated with the display device can be reduced. Additionally, processes for reducing flicker when refreshing the display device at different refresh rates are disclosed herein.
1. A method for refreshing multiple areas of a display device concurrently at different refresh rates, the method comprising:
comparing a first data frame to a second data frame;
determining a first group of rows of the second data frame, wherein the first group of rows are rows of data in the second data frame that are different than corresponding rows of data in the first data frame;
causing a first portion of the display device corresponding to the first group of rows to refresh at a first refresh rate;
determining a second group of rows of the second data frame, wherein (i) the second group of rows are rows of data in the second data frame that are same as corresponding rows of data in the first data frame, and (ii) the second group of rows comprises two or more rows; and
causing a second portion of the display device corresponding to the second group of rows to refresh at a second refresh rate, wherein (i) the second refresh rate is lower than the first refresh rate, and (ii) the causing the second portion of the display device to refresh at the second refresh rate comprises causing a group of driver circuits corresponding to the second group of rows to transition into a low state, wherein the group of driver circuits in the low state prevents driving signals from being outputted.
2. The method of claim 1 , wherein the display device is a light emitting diode (LED) display or a liquid crystal display (LCD) having an LED backlight.
3. The method of claim 1 , further comprising:
providing a selector signal to an output selector operatively coupled to the display device, wherein the selector signal causes the output selector to output a refresh signal to the display device.
4. The method of claim 1 , wherein the display device is a light emitting diode (LED) display or a liquid crystal display (LCD) having an LED backlight, and the method further comprising:
performing a compensation process at a boundary between the first portion of the display device and the second portion of the display device in order to mitigate flickering at the boundary within the second data frame.
5. The method of claim 1 , wherein determining the first group of rows of the second data frame includes determining whether the first group of rows of the second data frame corresponds to a type of content selected from a group consisting of high flicker content or low flicker content.
6. The method of claim 5 , further comprising:
when the first group of rows of the second data frame corresponds to the high flicker content, causing the first portion of the display device corresponding to the first group of rows to refresh at the first refresh rate; and
when the first group of rows of the second data frame corresponds to the low flicker content, causing the first portion of the display device corresponding to the first group of rows to refresh at a third refresh rate that is lower than the first refresh rate.
7. A machine-readable non-transitory storage medium storing instructions that, when executed by a processor included in a computing device, cause the computing device to carry out steps that include:
receiving a first data frame and a second data frame corresponding to image data to be displayed on a display device;
comparing a first group of rows of the first data frame to both a second group of rows and third group of rows in the second data frame;
determining that a first subset of rows of the first group of rows is different than the second group of rows;
determining that a second subset of rows of the first group of rows is the same as the third group of rows, wherein the second subset of rows comprise two or more rows;
causing a first group of driver circuits corresponding to the second group of rows to transition into a high state, wherein the first group of driver circuits in the high state allows driving signals to be outputted; and
causing a second group of driver circuits corresponding to the third group of rows to transition into a low state, wherein the second group of driver circuits in the low state prevents driving signals from being outputted.
8. The machine-readable non-transitory storage medium of claim 7 , wherein the high state causes the second group of rows to refresh, and the low state causes the third group of rows to remain unrefreshed.
9. The machine-readable non-transitory storage medium of claim 7 , further comprising:
determining whether the second group of rows and the third group of rows include flicker content that is above or below a high flicker threshold or a low flicker threshold.
10. The machine-readable non-transitory storage medium of claim 7 , further comprising:
performing a dithering process at a border between the second group of rows and the third group of rows.
11. The machine-readable non-transitory storage medium of claim 7 , further comprising:
performing an interpolation of two gamma curves to compensate for a difference between at least two refresh rates corresponding to the second group of rows and the third group of rows.
12. The machine-readable non-transitory storage medium of claim 7 , further comprising:
receiving a third data frame;
comparing a fourth group of rows in the third data frame to the third group of rows in the second data frame;
causing the second group of driver circuits to transition into the high state when the fourth group of rows is different than the third group of rows.
13. A computing device, comprising:
a display device;
a processor; and
a memory storing instructions that when executed by the processor cause the computing device to perform the steps of:
comparing a first data frame to a second data frame;
determining a first group of rows of the second data frame, wherein the first group of rows are rows of data in the second data frame that are different than corresponding rows of data in the first data frame;
causing a first portion of the display device corresponding to the first group of rows to refresh at a first refresh rate;
determining a remaining group of rows of the second data frame, wherein (i) the remaining group of rows are rows of data in the second data frame that are same as corresponding rows of data in the first data frame, and (ii) the remaining group of rows comprises two or more rows; and
causing a second portion of the display device corresponding to the remaining group of rows to refresh at a second refresh rate; wherein (i) the second refresh rate is lower than the first refresh rate, and (ii) the causing the second portion of the display device to refresh comprises causing a group of driver circuits corresponding to the remaining group of rows to transition into a low state, wherein the group of driver circuits in the low state prevents driving signals from being outputted.
14. The computing device of claim 13 , wherein the second refresh rate is equal to or less than half of the first refresh rate, and the display device is a light emitting diode (LED) display or a liquid crystal display (LCD) having an LED backlight.
15. The computing device of claim 13 , wherein the steps further include:
providing a selector signal to an output selector operatively coupled to the display device, wherein the selector signal causes the output selector to output a refresh signal to the display device.
16. The computing device of claim 13 , wherein the display device is a light emitting diode (LED) display or a liquid crystal display (LCD) having an LED backlight, and wherein the steps further include:
performing a compensation process at a boundary between the first portion of the display device having the first refresh rate and the second portion of the display device having the second refresh rate in order to mitigate flickering at the boundary caused by different refresh rates within the second data frame.
17. The computing device of claim 16 , wherein the compensation process is a dithering process at the boundary within the second data frame.
18. The computing device of claim 16 , wherein the compensation process includes performing an interpolation of two gamma curves to compensate for a difference between at least two refresh rates corresponding to the first portion of the display device and the second portion of the display device at the boundary within the second data frame.
19. The computing device of claim 13 , wherein determining the first group of rows of the second data frame includes determining whether the first group of rows of the second data frame corresponds to a type of content selected from a group consisting of high flicker content or low flicker content.
20. The computing device of claim 19 , wherein the steps further include:
when the first group of rows of the second data frame corresponds to the high flicker content, causing the first portion of the display device corresponding to the first group of rows of the second data frame to refresh at the first refresh rate; and
when the first group of rows of the second data frame corresponds to the low flicker content, causing the first portion of the display device corresponding to the first group of rows of the second data frame to refresh at a third refresh rate that is lower than both the first refresh rate and the second refresh rate.