Display device and head mount display device

A display device comprising:

• a substrate;
• a display panel comprising a plurality of display elements disposed on the substrate;
• and
• a diffraction panel comprising:
• a plurality of diffraction patterns disposed on a path of light emitted from the plurality of display elements, and disposed in a first direction to have a first period;
• each of the plurality of diffraction patterns comprising:
• a first layer and a second layer disposed on the first layer;
• and
• a refractive index of the first layer is higher than a refractive index of the second layer.

A head mount display device comprising:

• a display unit comprising:
• a plurality of display elements;
• and
• a plurality of diffraction patterns disposed on a path of light emitted from the plurality of display elements, and disposed in a first direction to have a first period;
• each of the plurality of diffraction patterns comprising:
• a first refractive layer, a second refractive layer disposed on the first refractive layer, and a third refractive layer disposed on the second refractive layer;
• and
• a refractive index of the second refractive layer is higher than refractive indexes of the first refractive layer and the third refractive layer;
• and
• a lens unit disposed on a path of light emitted from the display unit.