Patent ID: 8182719

Claim:
A device comprising a substrate and a film coating on said substrate, wherein said film coating comprises a quasi-amorphous pyroelectric compound, said compound comprising: a metal, a mixture of metals, or a semi conducting compound lacking spatial periodicity; said quasi-amorphous pyroelectric compound being an inorganic oxide compound having piezoelectric properties; said quasi-amorphous pyroelectric compound being a product of application of a mechanical strain to a substantially amorphous compound, said mechanical strain being created by passing said film through a steep unidirectional temperature gradient generating a gradient of mechanical strain, said gradient of mechanical strain having one in-plane component along the temperature gradient and one out-of-plane component, said out-of-plane component inducing an irreversible orientation of the molecular grouping due to compressive stress from the in-plane component; said temperature gradient being controlled so as to prevent crystallization of said compound, thereby obtaining highly stressed amorphous films and so that said compound is pyroelectric and has a pyroelectric vector whose direction cannot be changed or reversed, said film being clamped by the substrate creating mechanical constraints, such that volume expansion of said film is restricted.