Patent ID: 8248360

Claim:
A backlight control device which provides PWM control inverters with PWM signals generated in accordance with a dimming level input through a light receiving section that receives infrared light, the inverters causing lamps that emit visible light and infrared light to illuminate, the backlight control device comprising: a phase adjusting section configured to change a phase difference between a first PWM signal for driving a first lamp group and a second PWM signal for driving a second lamp group according to the dimming level when the dimming level is at least in a predetermined range of all dimming levels, the first and second lamp groups each including at least one lamp; a memory section having a table stored therein, the table having (i) the dimming level input through the light receiving section, (ii) a duty ratio corresponding to the dimming level, and (iii) the phase difference between the first and second PWM signals corresponding to the dimming level, wherein (i), (ii), and (iii) are associated with each other; a duty ratio obtaining section for referencing the table and obtaining the duty ratio corresponding to the input dimming level; a phase difference obtaining section for referencing the table and obtaining the phase difference corresponding to the input dimming level; and a PWM signal generating section for generating the first and second PWM signals in accordance with the duty ratio obtained by the duty ratio obtaining section, wherein the phase difference adjusting section is configured to set the phase difference between the first and second PWM signals, both of which are generated by the PWM signal generating section, to be the phase difference obtained by the phase difference obtaining section.