Window and display device including the same

A display device comprising:

• a display module;
• and
• a window disposed on the display module, wherein
• the window includes:
• a base substrate including a first surface and a second surface which face each other;
• and
• a filling portion,
• the base substrate has a concave portion defined on at least one of the first surface and the second surface,
• a difference between a refractive index of the base substrate at a wavelength of about 589 nm and a refractive index of the filling portion at a wavelength of about 589 nm is less than or equal to about 0.02,
• a difference between an Abbe No. of the base substrate and an Abbe No. of the filling portion is less than or equal to about 5.0,
• the filling portion fills the concave portion,
• the base substrate is a glass substrate, and
• the filling portion comprises:
• nanoparticles that include at least one of Al2O3 and glass particles;
• and
• an acrylic polymer resin.

A display device comprising:

• a folding region which is foldable with respect to a virtual folding axis extending in one direction;
• a non-folding region adjacent to the folding region;
• a display module;
• and
• a window made of glass disposed on the display module, wherein
• the window includes:
• a lower surface adjacent to the display module;
• an upper surface facing the lower surface;
• a concave portion depressed from at least one of the upper surface and the lower surface;
• and
• a filling portion filled in the concave portion,
• a refractive index of the filling portion is in a range of about 0.49 to about 1.51 at a wavelength of about 589 nm,
• the filling portion has an Abbe No. in a range of about 45 to about 50,
• a glass transition temperature of the filling portion is less than or equal to about −20° C., and
• the filling portion has an elongation greater than or equal to about 200%.