Patent ID: 8203522

Claim:
A method for driving an image display device comprising at least one backlight lamp and a display screen, the method comprising the acts of: receiving an image data signal; based on the image data signal, calculating a content-related backlight control signal for the backlight lamp for setting intensity of the backlight lamp; generating an average signal that represents a time-average of power consumed by the backlight lamp; comparing the average signal with a reference signal; based on the calculated content-related backlight control signal, taking into account result of the said comparing act, generating an actual backlight control signal for the backlight lamp, wherein the act of generating the actual backlight control signal comprises the acts of: setting a maximum value for the actual backlight control signal; defining a first transition value and a second transition value higher than or equal to the first transition value; generating the actual backlight control signal equal to ξ times the calculated content-related backlight control signal if the calculated content-related backlight control signal is less than the first transition value, wherein ξ is a predetermined factor; generating the actual backlight control signal equal to the maximum value if the calculated content-related backlight control signal is higher than the second transition value; generating the actual backlight control signal to have a value lower than ξ times the calculated content-related backlight control signal and lower than the maximum value if the calculated content-related backlight control signal is between the first transition value and the second transition value, and increasing the maximum value when the average signal is lower than the reference signal.