A device includes a substrate; a light blocking layer on the substrate; a passivation film covering the light blocking layer on the substrate; a thin film transistor on the passivation film; another passivation film covering the thin film transistor; a color filter on the another passivation film; and an insulation layer on the another passivation film and covering the color filter, wherein the light blocking layer is patterned using a composition including a heat resistance polymer, a cross-linking agent, a black colorant, and a solvent. A method of patterning the light blocking layer is also provided.