Display device

A display device, comprising:

• a display panel;
• and
• a cover window including a density control area and located on an image displaying surface of the display panel,
• wherein a plurality of voids are provided in the density control area, so that a refractive index of the density control area gradually changes from a first refractive index to a second refractive index, from a first side of the density control area to a second side of the density control area opposite to the first side, the first side is a side of the density control area that is in contact with a medium surrounding the display device,
• wherein a difference between the second refractive index and a refractive index of a material constituting the cover window is less than or equal to a first predetermined threshold,
• wherein a difference between the first refractive index and a refractive index of the medium is less than or equal to a second predetermined threshold,
• wherein the density control area comprises:
• an upper region comprising the first side of the density control area and comprising a first plurality of voids among the plurality of voids,
• a middle region disposed below the upper region and comprising a second plurality of voids among the plurality of voids,
• a lower region disposed below the middle region and comprising the second side of the density control area, the lower region comprising a third plurality of voids among the plurality of voids,
• wherein the refractive index of the density control area gradually increases from the upper region to the lower region of the density control area, and
• wherein a size of the second plurality of voids is greater than a size of the third plurality of voids, and the size of the second plurality of voids is smaller than a size of the first plurality of voids.