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US 4,983,839 AGranted
Pyroelectric materials
AssigneeThe United States of America as represented by the Secretary of the Army
InventorKrishna K. Deb
Life of this patent
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Abstract
The invention provides a new low Curie temperature pyroelectric material related sensing devices based on lead titanate doped with various percentages of calcium, lanthanum, bismuth, cobalt and tungsten processed to provide a fine grain structure.
Claims16
An improved pyroelectric material comprising:
- modified lead titanate having an average grain size between 1 and 2 microns and wherein at least twenty percent of the lead has been replaced by calcium to lower the temperature at which the pyroelectric coefficient peaks occur and thus provide an improved Figure of Merit.
An electromagnetic radiation sensor comprising:
- a thin plate of lead-calcium-titanate having an average grain size between 1 and 2 microns, a thickness of approximately 25 microns and an atomic ratio of lead to calcium no greater than 4;
- said plate being electrically polarizable normal to its broad surfaces;
- and
- a separate electrode of highly conductive material intimately contacting each of the two opposed broad surfaces of said plate to form an anode and a cathode.
1 more element
A pyroelectric imager with an array of ferroelectric sensors, wherein:
- each sensor includes a thin layer of lead-calcium-titanate having an average grain size between 1 and 2 microns, a thickness of approximately 25 microns and an atomic ratio of lead to calcium less than four.
Dependencies are inferred from the claim text.