Thermal pattern sensor comprising several pixels arranged on a substrate, each pixel including at least one pyroelectric capacitance formed by at least one portion of pyroelectric material arranged between at least one lower electrode and at least one upper electrode, with the lower electrode arranged between the substrate and the portion of pyroelectric material, and in which at least one protective dielectric layer is arranged between the portion of pyroelectric material and the upper electrode and comprises at least one of the following materials: fluoropolymer, self-assembled molecular monolayer, dielectric material soluble in a solvent orthogonal to the pyroelectric material.