Display device

A display device comprising:

• a display unit that includes pixels arranged in a matrix therein, each of the pixels including a first sub-pixel that displays a first color component, a second sub-pixel that displays a second color component, a third sub-pixel that displays a third color component, and a fourth sub-pixel that displays a fourth color component different from the first sub-pixel, the second sub-pixel, and the third sub-pixel;
• a surface light source that irradiates the display unit;
• and
• a signal processing unit that receives input signals that are capable of being displayed with the first sub-pixel, the second sub-pixel, and the third sub-pixel, and calculates output signals to the first sub-pixel, the second sub-pixel, the third sub-pixel, and the fourth sub-pixel, wherein
• the signal processing unit calculates a light quantity of the surface light source necessary for each of the pixels, and calculates a frequency of pixels belonging to each of a plurality of partitions using the obtained light quantity of the surface light source as a variable;
• the signal processing unit obtains a cumulative frequency by sequentially adding the frequency of pixels from a partition having the maximum light quantity among the partitions, and calculates an index value for each of the partitions, the index value being for each of the partitions, by adding the cumulative frequency of a target partition to a value obtained by multiplying an index value of a partition lying closer to the partition having the maximum light quantity than the target partition by a positive coefficient set for the target partition;
• and
• the signal processing unit controls luminance of the surface light source based on a partition in which the index value exceeds a threshold.