Display device and method for controlling display device

A method for controlling a display device that has a display panel which displays a frame image for each one frame period, and a backlight unit that illuminates the display panel from a rear face of the display panel, the backlight unit including a first light source unit that illuminates the display panel, and a second light source unit that illuminates the display panel, the method comprising:

• a first step of outputting a drive signal to the first light source unit to drive the first light source unit during a first drive period in the one frame period;
• and
• a second step of outputting a drive signal to the second light source unit to drive the second light source unit during a second drive period in the one frame period after the driving of the first light source unit is started, wherein
• the first light source unit and the second light source unit are driven in the first step and the second step so that the one frame period has an overlapped period, in which the first drive period and the second drive period overlap each other,
• a PWM signal is outputted, as the drive signal, to the first light source unit in the overlapped period in the first step, the PWM signal turning the first light source unit on and off with a predetermined pulse width,
• a PWM signal is outputted, as the drive signal, to the second light source unit in the overlapped period in the second step, the PWM signal turning the second light source unit on and off with a predetermined pulse width, and
• a phase of the PWM signal to be outputted to the first light source unit and a phase of the PWM signal to be outputted to the second light source unit are shifted from each other in the first step and the second step.