Patent ID: 8648969

Claim:
A brightness adjusting device, comprising: a brightness setting section that accepts an input of brightness change information that comprises an instruction to change a brightness setting value; a brightness adjusting section that performs a brightness adjustment by one of a brightness adjusting unit and a video signal adjusting unit having different characteristics from each other, in accordance with an instruction that is input from the brightness setting section; a determining section that determines whether the brightness adjustment of the brightness adjusting section switches from the brightness adjusting unit to the video signal adjusting unit; an output section that outputs an alarm when the brightness adjustment of the brightness adjusting section is determined to switch from the brightness adjusting unit to the video signal adjusting unit based on a determination result of the determining section; and a storage section that stores first and second reference values comprising brightness setting values in cases of the brightness adjustment switching between the brightness adjusting unit and the video signal adjusting unit, the first reference value being less than the second reference value, wherein the brightness adjusting section performs a brightness adjustment by the video signal adjusting unit in a case where the brightness change information from the brightness setting section is in a range from a minimum value to the first reference value and in a range from the second reference value to a maximum value, and the brightness adjusting section performs a brightness adjustment by the brightness adjusting unit in a case where the brightness change information from the brightness setting section is in a range from the first reference value to the second reference value.