An optical mask includes a light-to-heat conversion layer with an improved temperature profile. The optical masks may comprise a light-transmitting base substrate; a first reflective pattern layer which is formed on the light-transmitting base substrate comprising a first opening portion transmitting light emitted from under the light-transmitting base substrate and a first reflective portion reflecting the light; a second reflective pattern layer which is formed over the first opening portion comprising a second opening portion overlapping a first area of the first opening portion and a second reflective portion overlapping a second area of the first opening portion; and a light-to-heat conversion pattern layer which is formed on the light-transmitting base substrate, being disposed in the first area of the first opening portion, absorbing at least a part of the light, and converting the light absorbed into heat.