Pulsed backlight systems and methods
Aspects of the subject technology relate to pulsed backlight operation for a display backlight. Backlight pulse patterns are provided that include steady state pulse patterns to be applied during operation of a liquid crystal display unit of the display at a corresponding frame rate. The backlight pulse patterns can be arranged to prevent visible artifacts such as flicker or strobing, particularly at or near a transition between LCD frame rates. In some scenarios, transition pulse patterns are provided.
1. A method of operating an electronic device having a display with a backlight unit and a liquid crystal display (LCD) unit, the method comprising:
displaying first display content with the LCD unit at a first LCD frame rate;
while providing the first display content at the first LCD frame rate, providing backlight pulses with a first backlight pulse pattern;
displaying second display content with the LCD unit at a second LCD frame rate;
while providing the second display content at the second LCD frame rate, providing backlight pulses with a second backlight pulse pattern;
splitting at least a first pulse of the second backlight pulse pattern between at least one pulse of the first backlight pulse pattern and at least one other pulse of the second backlight pulse pattern; and
wherein splitting at least the first pulse of the second backlight pulse pattern comprises preventing execution of the first pulse of the second backlight pulse pattern and adding equal portions of the first pulse of the second backlight pulse pattern to each of an immediately preceding pulse and an immediately following pulse.
2. The method of claim 1 , further comprising operating a digital filter to cause the equal splitting.
3. The method of claim 1 , wherein splitting at least the first pulse of the second backlight pulse pattern comprises splitting the first pulse of the second backlight pulse pattern and at least one of another pulse of the second backlight pulse pattern or a pulse of the first backlight pulse pattern.
4. The method of claim 3 further comprising operating a digital filter to cause the first backlight pulse pattern.
5. The method of claim 3 further comprising operating a digital filter to cause the second backlight pulse pattern.
6. A electronic device with a display, the display comprising:
a backlight unit;
a liquid crystal display (LCD) unit configured to display first display content a first LCD frame rate,
a controller configured to cause the backlight unit to pulse a first backlight pulse pattern while the LCD unit provides the first display content at the first LCD frame rate;
the LCD unit further configured to display second display content at a second LCD frame rate;
the controller is further configured to cause the backlight unit to pulse a second backlight pulse pattern while the LCD unit provides the second display content at the second LCD frame rate;
the controller is further configured to split at least a first pulse of the second backlight pulse pattern between at least one pulse of the first backlight pulse pattern and at least one other pulse of the second backlight pulse pattern; and
wherein splitting at least the first pulse of the second backlight pulse pattern comprises preventing execution of the first pulse of the second backlight pulse pattern and adding equal portions of the first pulse of the second backlight pulse pattern to each of an immediately preceding pulse and an immediately following pulse.
7. The electronic device of claim 6 , further comprising operating a digital filter to cause the equal splitting.
8. The electronic device of claim 6 , wherein splitting at least the first pulse of the second backlight pulse pattern comprises splitting the first pulse of the second backlight pulse pattern and at least one of another pulse of the second backlight pulse pattern or a pulse of the first backlight pulse pattern.
9. The electronic device of claim 8 further comprising:
a digital filter configured to cause the first backlight pulse pattern.
10. The electronic device of claim 8 further comprising:
a digital filter configured to cause the second backlight pulse pattern.
11. A non-transitory computer-readable storage medium encoded with data and instructions, when executed by an electronic device having a display with a backlight unit and a liquid crystal display (LCD) unit, further causing the electronic device to:
display first display content with the LCD unit at a first LCD frame rate;
while providing the first display content at the first LCD frame rate, provide backlight pulses with a first backlight pulse pattern;
display second display content with the LCD unit at a second LCD frame rate;
while providing the second display content at the second LCD frame rate, provide backlight pulses with a second backlight pulse pattern;
split at least a first pulse of the second backlight pulse pattern between at least one pulse of the first backlight pulse pattern and at least one other pulse of the second backlight pulse pattern; and
wherein the splitting at least the first pulse of the second backlight pulse pattern comprises preventing execution of the first pulse of the second backlight pulse pattern and adding equal portions of the first pulse of the second backlight pulse pattern to each of an immediately preceding pulse and an immediately following pulse.
12. The non-transitory computer-readable storage medium of claim 11 , further causing the electronic device to:
operate a digital filter to cause the equal splitting.
13. The non-transitory computer-readable storage medium of claim 11 , wherein the splitting at least the first pulse of the second backlight pulse pattern comprises splitting the first pulse of the second backlight pulse pattern and at least one of another pulse of the second backlight pulse pattern or a pulse of the first backlight pulse pattern.
14. The non-transitory computer-readable storage medium of claim 13 further comprising operating a digital filter to cause the first backlight pulse pattern.
15. The non-transitory computer-readable storage medium of claim 13 further comprising operating a digital filter to cause the second backlight pulse pattern.