Electronic device controlling luminance and method for controlling luminance thereof

An electronic device comprising:

• a display device;
• a processor operatively connected to the display device;
• and
• a memory operatively connected to the processor,
• wherein the memory stores one or more instructions that when executed, cause the processor to:
• after a condition to turn off the screen is satisfied, according to a determination that in a turned on state of a screen of the display device is maintained for a first specific time, determine a second screen code value as a code value obtained by decreasing a first screen code value by a decrement value, wherein the first screen code value corresponds to a luminance value of the screen;
• and
• change the luminance value of the screen to correspond to the determined second screen code value.