Backlight control system and method
View Patent ↗A backlight control system and method are disclosed. An overdrive device modifies a backlight duty signal according to a current-frame backlight duty signal and a previous-frame backlight duty signal. In one embodiment, the overdrive device is implemented with a lookup table that outputs the modified backlight duty signal. The backlight driven by the modified backlight duty signal then emits light to a display panel, thereby increasing a response time of the backlight.
1. A backlight control system, comprising:
a backlight that emits light to a display panel; and
an overdrive device that modifies a backlight duty signal according to a current-frame backlight duty signal and a previous-frame backlight duty signal, therefore increasing response time of the backlight driven by the modified backlight duty signal;
wherein the overdrive device compares a duty value of the current-frame backlight duty signal with a duty value of the previous-frame backlight duty signal;
wherein when the duty value of the previous-frame backlight duty signal is smaller than the duty value of the current-frame backlight duty signal, the modified backlight duty signal is generated with a magnitude greater than that of the current-frame backlight duty signal and applied to the backlight;
wherein when the duty value of the previous-frame backlight duty signal is greater than the duty value of the current-frame backlight duty signal, the modified backlight duty signal is generated with a magnitude smaller than that of the current-frame backlight duty signal and applied to the backlight; and
wherein when the duty value of the previous-frame backlight duty signal is about equal to the duty value of the current-frame backlight duty signal, the modified backlight duty signal is generated with a magnitude about equal to that of the current-frame backlight duty signal and applied to the backlight.
2. The system of claim 1 , wherein the overdrive device includes a lookup table which outputs the modified backlight duty signal.
3. The system of claim 2 , wherein the lookup table has an axis representing the previous-frame backlight duty signal, and another axis representing the current-frame backlight duty signal.
4. The system of claim 1 , wherein the backlight duty signal is a pulse-width-modulation (PWM) signal with a pulse width proportional to a required illumination of the backlight.
5. The system of claim 1 , further comprising a buffer for storing and providing the previous-frame backlight duty signal.
6. The system of claim 1 , wherein the backlight comprises a plurality of cold cathode fluorescent lamps (CCFL), a plurality of light-emitting diodes (LED), or a combination thereof.
7. A backlight control method, comprising:
modifying a backlight duty signal according to a current-frame backlight duty signal and a previous-frame backlight duty signal, therefore increasing a response time of a backlight; and
driving the backlight to emit light to a display panel according to the modified backlight duty signal;
wherein the step of modifying the backlight duty signal comprises:
comparing a duty value of the current-frame backlight duty signal with a duty value of the previous-frame backlight duty signal;
generating the modified backlight duty signal with a magnitude greater than that of the current-frame backlight duty signal and applying it to the backlight, when the duty value of the previous-frame backlight duty signal is smaller than the duty value of the current-frame backlight duty signal;
generating the modified backlight duty signal with a magnitude smaller than that of the current-frame backlight duty signal and applying it to the backlight, when the duty value of the previous-frame backlight duty signal is greater than the duty value of the current-frame backlight duty signal; and
generating the modified backlight duty signal with a magnitude about equal to that of the current-frame backlight duty signal and applying it to the backlight, when the duty value of the previous-frame backlight duty signal is about equal to the duty value of the current-frame backlight duty signal.
8. The method of claim 7 , further comprising providing a lookup table which outputs the modified backlight duty signal.
9. The method of claim 8 , wherein the lookup table has an axis representing the previous-frame backlight duty signal, and another axis representing the current-frame backlight duty signal.
10. The method of claim 7 , wherein the backlight duty signal is a pulse-width-modulation (PWM) signal with a pulse width proportional to a required illumination of the backlight.
11. The method of claim 7 , further comprising storing and providing the previous-frame backlight duty signal.
12. The method of claim 7 , wherein the backlight comprises cold cathode fluorescent lamps (CCFL) and/or light-emitting diodes (LED).