A display device includes a first pixel and a second pixel. The second pixel is controlled to emit light in a predetermined range in a first time period and to not emit light in the predetermined range in a second time period during which the first pixel emits light. The first pixel includes a first organic emission layer having a first thickness and the second pixel includes a second organic emission layer having a second thickness different from the first thickness. A resonance pattern is formed in the second pixel to emit light in a melatonin production inhibition wavelength range that corresponds to the predetermined range. The first pixel may emit blue light, green light, red light, or another color of light including white light.
