A display unit of a display device includes a light emitting unit and a light converting layer disposed on the light emitting unit. The display unit emits an output light under an operation of the highest gray level, and the output light has an output spectrum. An intensity integral of the output spectrum from 380 nm to 489 nm defines as a first intensity integral, an intensity integral of the output spectrum from 490 nm to 780 nm defines as a second intensity integral, a ratio of the first intensity integral over the second intensity integral defines as a first ratio, and the first ratio is greater than 0% and less than or equal to 7.5%.