Embodiments of the disclosure are related to polyimide substrates and display devices, a plurality of intaglio patterns are formed on at least a portion of one surface of a polyimide substrate, a high transmissive filling is disposed inside the intaglio pattern, thus an overall transmittance of the polyimide substrate is enhanced. Furthermore, the filling having a certain range of a coefficient of thermal expansion is disposed in the intaglio pattern to maintain a heat resistance of the polyimide substrate, an element being required a high temperature process could be disposed on the polyimide substrate having an enhanced transmittance.