Display device, electronic apparatus, and method for driving display device

A display device comprising:

• an image display panel in which a plurality of pixels are arranged in a two-dimensional matrix;
• a light source unit including a light guide plate and a plurality of light sources arranged facing an entrance surface of the light guide plate;
• and
• a signal processing circuitry that controls the pixels based on an input signal of an image and controls an irradiation amount of light from the light source unit, wherein the signal processing circuitry comprises:
• a tentative expansion coefficient calculating circuitry that calculates, for each of the pixels, a tentative expansion coefficient serving as a tentative coefficient used to expand the input signal of the image;
• a tentative index value calculating circuitry that calculates, for each of the pixels, a tentative index value serving as an index used to calculate the irradiation amount of light from the light source unit based on the tentative expansion coefficient;
• a low-saturation pixel detecting circuitry that detects low-saturation pixels having saturation based on the input signal lower than certain saturation in a certain region serving as at least one of a plurality of regions obtained by dividing an image display surface of the image display panel;
• a light irradiation amount calculating circuitry that calculates a comparative light irradiation amount based on a result of detection performed by the low-saturation pixel detecting circuitry, a display quality maintenance reference value at which a display quality of a color displayed by the low-saturation pixels is maintained, and an index value calculated based on the tentative index value of pixels included in the certain region and calculates, based on the comparative light irradiation amount, a light irradiation amount serving as the irradiation amount of light output from the light source unit to the certain region;
• and
• a chunk calculating circuitry that determines whether the tentative index value is continuous in a plurality of pixels, determines, when determining that the tentative index value is continuous, a region of continuous pixels to be a chunk, and determines the tentative index value of the continuous pixels to be a chunk tentative index value, and
• the index value is calculated based on the chunk tentative index value of the chunk included in the certain region.

A method for driving a display device including an image display panel in which a plurality of pixels are arranged in a two-dimensional matrix, a light source unit that outputs light to the image display panel, and a signal processing circuitry that controls the pixels based on an input signal of an image and controls irradiation of light from the light source unit, the method for driving the display device comprising:

• calculating, for each of the pixels, a tentative expansion coefficient serving as a tentative coefficient used to expand the input signal of the image;
• calculating, for each of the pixels, a tentative index value serving as an index used to calculate an irradiation amount of light from the light source unit based on the tentative expansion coefficient;
• detecting low-saturation pixels having saturation based on the input signal lower than certain saturation in a certain region serving as at least one of a plurality of regions obtained by dividing an image display surface of the image display panel;
• and
• calculating a comparative light irradiation amount based on a result of detection obtained at the detecting the low-saturation pixels, a display quality maintenance reference value at which a display quality of a color displayed by the low-saturation pixels is maintained, and an index value calculated based on the tentative index value of pixels included in the certain region and calculating, based on the comparative light irradiation amount, a light irradiation amount serving as the irradiation amount of light output from the light source unit to the certain region.