DISPLAY BACKLIGHT MODULATION

• US 20140062329A1
• Filed: 12/29/2011
• Published: 03/06/2014
• Est. Priority Date: 12/29/2011
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Zhang, Yanli, Takagi, Akihiro, Bhowmik, Achintya K., Nanduri, Anil V.
• Granted Patent: US 9,538,624 B2
• Time in Patent Office: Days
• US Class Current: 315/210
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: H05B 47/16 by timing means

Abstract

An apparatus may include a backlight for illuminating a liquid crystal display and a control module for controlling the illumination of the backlight. The control module may alternate between turning the backlight on and off at a first frequency and turning the backlight on and off at a second frequency.

Claims

1. An apparatus, comprising:

a control module to control the illumination of a backlight configured to illuminate a liquid crystal display, wherein the control module is configured to alternately turn the backlight on and off at a first frequency and turn the backlight on and off at a second frequency, the second frequency being different than the first frequency.

2. The apparatus of claim 1, wherein the backlight is either a light emitting diode or a cold cathode fluorescent lamp.

3. The apparatus of claim 1, wherein the control module is to use a first pulse width modulated signal at the first frequency to turn the backlight on and off at the first frequency and a second pulse width modulated signal at the second frequency to turn the backlight on and off at the second frequency.

4. The apparatus of claim 3, wherein the duty cycle of the first pulse width modulated signal is equal to the duty cycle of the second pulse width modulated signal.

5. The apparatus of claim 1, wherein the control module is to turn the backlight on and off at a first frequency for at least one minute intervals and turn the backlight on and off at a second frequency for at least one minute intervals.

6. An apparatus, comprising:

a first backlight configured to illuminate a first portion of a liquid crystal display;

a second backlight configured to illuminate a second portion of the liquid crystal display; and

a control module to control the illumination of the first and second backlights, wherein the control module is configured to turn the first backlight on and off at a first frequency and turn the second backlight on and off at a second frequency, the second frequency being different than the first frequency.

7. The apparatus of claim 6, wherein the first and second backlights are either light emitting diodes or cold cathode fluorescent lamps.

8. The apparatus of claim 6, wherein the control module is to produce a first pulse width modulated signal at the first frequency to turn the backlight on and off at the first frequency and a second pulse width modulated signal at the second frequency to turn the backlight on and off at the second frequency.

9. The apparatus of claim 8, wherein the duty cycle of the first pulse width modulated signal is equal to the duty cycle of the second pulse width modulated signal.

10. The apparatus of claim 6, wherein the control module is to change the first frequency to a third frequency.

11. The apparatus of claim 10, wherein the third frequency is to be random chosen.

12. The apparatus of claim 10, wherein the control module is to randomly change the first frequency to the third frequency.

13. The apparatus of claim 6, further comprising a third backlight configured to illuminate a third portion of the liquid crystal display.

14. The apparatus of claim 13, wherein the control module is to control the illumination of the third backlight and is further configured to turn the third backlight on and off at a third frequency.

15. An electronic device that comprises the apparatus of claim 6.

16. A method, comprising:

turning a first backlight on and off at a first frequency, the first backlight illuminating a first portion of a liquid crystal display; and

turning a second backlight on and off at a second frequency, the second backlight illuminating a second portion of the liquid crystal display, the second frequency being different than the first frequency.

17. The method of claim 16, further comprising changing the first frequency at which the first backlight is turned on and off.

18. The method of claim 17, wherein the first frequency is changed at a random interval and to a random frequency.

19. The method of claim 17, further comprising changing the second frequency at which the second backlight is turned on and off.

20. The method of claim 19, wherein the second frequency is changed at a random interval and to a random frequency.

21. The method of claim 16, wherein only the first backlight is turned on and off at a first frequency during a first period and only the second backlight is turned on and off at a second frequency during a second period.

22. An apparatus, comprising:

a battery;

a backlight configured to use power from the battery to illuminate a liquid crystal display; and

a control module configured to control the illumination of the backlight by alternating between turning the backlight on and off at a first frequency and turning the backlight on and off at a second frequency, the second frequency being different than the first frequency.

23. The system of claim 22, wherein the backlight is either a light emitting diode or a cold cathode fluorescent lamp.

24. The system of claim 22, wherein the control module is to use a first pulse width modulated signal at the first frequency to turn the backlight on and off at the first frequency and a second pulse width modulated signal at the second frequency to turn the backlight on and off at the second frequency.

25. The system of claim 24, wherein the duty cycle of the first pulse width modulated signal is equal to the duty cycle of the second pulse width modulated signal.

26. The system of claim 22, wherein the control module is to turn the backlight on and off at a first frequency for at least one minute intervals and turn the backlight on and off at a second frequency for at least one minute intervals.

28. The medium of claim 22, wherein the backlight is to be turned on and off by a control module and the control module is to use a first pulse width modulated signal at the first frequency to turn the backlight on and off at the first frequency and a second pulse width modulated signal at the second frequency to turn the backlight on and off at the second frequency.

29. The medium of claim 28, wherein the duty cycle of the first pulse width modulated signal is equal to the duty cycle of the second pulse width modulated signal.

27. A non-transitory, computer-readable medium storing instructions to be executed by a processor to perform a method, the method comprising:

turning a backlight, configured to illuminate a liquid crystal display, on and off at a first frequency; and

turning the backlight on and off at a second frequency, the second frequency being different than the first frequency.