System, method, and computer program product for combining low motion blur and variable refresh rate in a display

Patent metadata

Field	Value
Publication number	US-9773460-B2
Application number	US-201314058142-A
Country	US
Kind code	B2
Filing date	Oct 18, 2013
Priority date	Oct 18, 2013
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

A system, method, and computer program product are provided for combining low motion blur and variable refresh rate in a display. In one embodiment, a hold-type display is operated in a first mode of operation where the hold-type display is dynamically refreshed such that the hold type display handles updates to image frames at unpredictable times and where for each of the image frames a backlight of the hold-type display is activated for an entire duration of display of the image frame. Additionally, it is determined that at least one predefined condition has been met. Further, in response to the determination, the hold-type display is operated in a second mode of operation where the hold-type display is statically refreshed such that the hold-type display handles updates to image frames at regular intervals and where for each of the image frames the backlight of the hold-type display is flashed.

First claim

What is claimed is:

1. A method, comprising:
operating a hold-type display in a first mode of operation, wherein the hold-type display is dynamically refreshed such that the hold-type display handles updates to image frames at unpredictable times, and wherein, in the first mode of operation, a backlight of the hold-type display is activated for the entirety of a duration of time each of the image frames is displayed;
determining that at least one first predefined condition has been met;
in response to the determination that the at least one first predefined condition has been met, operating the hold-type display in a second mode of operation wherein the hold-type display is dynamically refreshed, and wherein, in the second mode of operation, the backlight of the hold-type display is flashed during the duration of time each of the image frames is displayed, wherein a time the backlight is activated during the duration of time each of the image frames is displayed is less than the entirety of the duration of time each of the image frames is displayed;
determining that at least one second predefined condition has been met; and
in response to the determination that the at least one second predefined condition has been met, returning operation of the hold-type display from the second mode of operation to the first mode of operation,
wherein the time the backlight is activated for a particular image frame in the second mode of operation is determined as a function of an estimated duration of time that the particular image frame will be displayed, and
wherein the estimated duration of time for a particular image frame is determined based on a duration of time a preceding image frame is displayed in combination with information received from a processor rendering the particular image frame, the information indicating for each rendering operation performed by the processor, any difference between a time taken to perform the operation when rendering the particular image frame and a time taken to perform the operation when rendering the preceding image frame.

2. The method of claim 1 , wherein the at least one predefined condition includes a predefined refresh rate of the hold-type display, such that determining that the at least one predefined condition has been met is based on a determination that the hold-type display is operating at or above the predefined refresh rate.

3. The method of claim 2 , wherein temporal hysteresis is utilized with respect to the predefined threshold rate for determining whether the at least one predefined condition has been met, including:
determining that the at least one predefined condition has been met when the hold-type display is operating at or above the predefined refresh rate for a preconfigured amount of time.

4. The method of claim 1 , wherein the at least one predefined condition includes a determination that fewer than a threshold number of image frame pairs previously displayed in sequence differed in duration by less than a threshold amount.

5. The method of claim 1 , wherein the at least one predefined condition includes a determination that an application generating the image frames is either:
included in a whitelist of applications predetermined to be suitable with operation of the hold-type display in the second mode of operation, or
not included in a blacklist of applications predetermined to not be suitable with operation of the hold-type display in the second mode of operation.

6. The method of claim 1 , wherein a desired average level of light is constant across a plurality of image frames displayed during operation of the hold-type display in the second mode of operation.

7. The method of claim 1 , wherein transitioning from operating the hold-type display in the first mode of operation to operating the hold-type display in the second mode of operation includes:
displaying an image frame in the first mode of operation, and then
displaying a next image frame in the second mode of operation with the backlight of the hold-type display being flashed at a level of intensity that, in combination with the time the backlight is activated, produces a desired level of light output by the backlight.

8. The method of claim 1 , wherein transitioning from operating the hold-type display in the first mode of operation to operating the hold-type display in the second mode of operation includes:
displaying an image frame in the first mode of operation, and then
displaying a sequence of next image frames in the second mode of operation with the backlight of the hold-type display being flashed for each of the next image frames at incrementally intermediate levels of intensity that are between a level of intensity for the backlight during the first mode of operation that, in combination with the time the backlight is activated, produces a desired level of light output for the second mode of operation, and further
displaying a subsequent image frame in the second mode of operation with the backlight of the hold-type display being flashed at a level of intensity that, in combination with the time the backlight is activated, produces the desired level of light output for the second mode of operation.

9. The method of claim 1 , wherein displaying an image frame while operating the hold-type display in the second mode of operation comprises:
receiving information from the processor rendering a next image frame to be displayed by the hold-type display, the information indicating an error in the estimated duration of time during which the image frame is to be displayed, and
controlling of the backlight to correct for the indicated error.

10. The method of claim 9 , wherein the error indicates that the duration of time during which the image frame is to be displayed is longer than the estimated duration of time, displaying the image frame while operating the hold-type display in the second mode of operation further comprises:
determining a level of intensity that, in combination with the time the backlight is activated, produces a desired level of light output by the backlight for the image frame as a function of the longer duration of time for the image frame indicated by the information received from the processor, and
correcting for the error by re-activating the backlight after the flashing of the backlight for the image frame in order to achieve the desired level of light output that is the function of the longer duration of time.

11. The method of claim 1 , wherein displaying an image frame while operating the hold-type display in the second mode of operation, for each pixel of the image frame, comprises:
identifying a value of the pixel to be displayed,
modifying the value of the pixel as a function of both: a determined duration of time during which the image frame is to be displayed, and a location of the pixel in the image frame, and
displaying the pixel using the modified value.

12. The method of claim 11 , wherein the determined duration of time during which the image frame is to be displayed includes either an estimated duration of time or an actual duration of time.

13. The method of claim 1 , wherein for each of the image frames an actual level of light output by the backlight is measured to determine whether the actual level of light output differs from a desired level of light output, such that when it is determined that the actual level of light output differs from the desired level of light output, a level of intensity of the backlight for the current and/or future frames is adjusted to compensate for the determined difference.

14. The method of claim 1 , wherein the image frames a

Assignees

• Nvidia Corp

Inventors

• Verbeure Tom
• Slavenburg Gerrit A
• Fox Thomas F
• Schutten Robert Jan
• Lucas Luis Mariano
• Janssens Marcel Dominicus

Classifications

• G09G3/36 Primary

  using liquid crystals · CPC title

• G09G3/3406

  Control of illumination source (illumination devices structurally associated with liquid crystal cells G02F1/1336) · CPC title

• G09G2310/0237

  Switching ON and OFF the backlight within one frame · CPC title

• G09G2320/0257

  Reduction of after-image effects · CPC title

• G09G2320/0261

  in the context of movement of objects on the screen or movement of the observer relative to the screen · CPC title