Patent ID: 8008874

Claim:
A brightness adjusting device of a display device, comprising: an outside temperature detecting unit which detects an outside temperature of the display device with an outside temperature sensor device existing outside the display device; an inside temperature detecting unit which detects an inside temperature of the display device with an inside temperature sensor device existing inside the display device; a product inside temperature table storing unit in which a temperature difference between the outside temperature and the inside temperature, and a warm-up time of the display device are associated with each other beforehand to be stored as a product inside temperature table; a target brightness value table storing unit in which the warm-up time and a target brightness value, which is a brightness value becoming a target of the display device at the warm-up time, are associated with each other beforehand to be stored as a target brightness value table; a warm-up time determining unit which calculates a temperature difference between the outside temperature detected by the outside temperature detecting unit and the inside temperature detected by the inside temperature detecting unit, and reads and determines a warm-up time corresponding to the calculated temperature difference, as an estimated warm-up time, from the product inside temperature table stored in the product inside temperature table storing unit; a target brightness value determining unit which reads and determines a target brightness value, which corresponds to the estimated warm-up time read and determined by the warm-up time estimating unit, from the target brightness value table stored in the target brightness value table storing unit; and a brightness value setting unit which sets a brightness value of the display device according to the target brightness value read and determined by the target brightness value calculating unit.