Display device capable of generating color of light close to or identical to blue primary color of DCI-P3 color gamut

A display device, comprising:

• at least one sub-pixel, being a blue sub-pixel, and the at least one sub-pixel comprising:
• a transistor;
• a light emitting unit electrically connected to the transistor;
• and
• a light converting layer disposed on the light emitting unit,
• wherein the at least one sub-pixel emits an output light under an operation of the highest gray level, the output light is a final visual light of the blue sub-pixel of the display device, the output light having an output spectrum, an intensity integral of the output spectrum from 380 nm to 493 nm defines as a first intensity integral, an intensity integral of the output spectrum from 494 nm to 580 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 ranges from 5 to 20, and
• wherein a y-coordinate value of the output spectrum in CIE 1931 xy chromaticity diagram is in a range from 0.04 to 0.08.