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US 5,120,602 AGranted
Optical elements and method of manufacture
AssigneeRaytheon Company
InventorsRandal W. Tustison, Dennis G. Montanari
Life of this patent
Estimating the term…
Abstract
An optical element includes a base layer of a first material selected from the group consisting of gallium arsenide, gallium phosphide, cadmium telluride, mercury cadmium telluride, zinc sulfide and zinc selenide, and a coating layer of the selected base layer material. The coating layer has a predetermined degree of intrinsic compressive stress to protect the base layer.
Claims13
An optical element comprising:
- a base comprising a material having a first intrinsic compressive stress characteristic and a predetermined optical transmittance over at least a portion of an optical range of about 2 microns to 30 microns;
- and
- a coating layer of the material of said base disposed on said base with said coating layer having a second intrinsic compressive stress characteristic having a value greater than a value of said first intrinsic compressive stress characteristic of the material of the base.
An optical element, comprising:
- a base having a thickness of at least about 0.05 inches, of a material selected from the group consisting of zinc sulfide and zinc selenide having a first predetermined optical transmissivity over at last the optical range of about 8 microns to 12 microns;
- and
- a coating layer disposed on said base, of the material of said base, and having a thickness in the range of about 1 micron to 8 microns, with said optical element having a grain structure with a first portion of said grain structure of the element corresponding to that of the base, being substantially uniform and having a first grain size characteristic, and a second portion of the grain structure of the element corresponding to that of the coating, having a second grain size characteristic smaller than said first grain size characteristic of the base and interfacing with that of the base in a region of high grain boundary mismatch.
Dependencies are inferred from the claim text.