Display device and control method therefor having low grayscale mode and high grayscale mode

A control method of a display device comprising a display panel, a light emitting unit comprising a plurality of light emitting diodes (LEDs), the light emitting unit being configured to be driven in one of a low grayscale mode or a high grayscale mode in which an output range of a driving current is reduced, and a driving circuit configured to control the driving current applied to the light emitting unit based on image data of a frame, the control method comprising:

• obtaining a selected mode of one of the low grayscale mode or the high grayscale mode based on a required luminance included in the image data of the frame, wherein the high grayscale mode is selected for outdoor display;
• obtaining a mode minimum value and a mode maximum value of the driving current according to the selected mode, wherein the mode minimum value of the low grayscale mode is a minimum value of the output range of the driving current and the mode maximum value of the high grayscale mode is a maximum value of the output range of the driving current, wherein the mode maximum value of the driving current in the low grayscale mode is lower than the mode maximum value of the driving current in the high grayscale mode and a maximum driving current output value of the driving circuit, and wherein the mode minimum value of the driving current in the high grayscale mode is greater than the mode minimum value of the driving current in the low grayscale mode and a minimum driving current output value of the driving circuit;
• reducing the output range of the driving current to a reduced output range corresponding to the mode minimum value and the mode maximum value of the driving current according to the selected mode;
• increasing a number of grayscale levels that fall within the reduced output range;
• increasing a number of luminance levels expressible to correspond to the increased number of grayscale levels within the reduced output range to obtain the increased number of luminance levels;
• and
• controlling the driving circuit based on the increased number of luminance levels.