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