US 12,468,073 B2
Method of strengthening an optical element
Ralph Korenstein, Natick, MA (US); and Christopher S. Nordahl, Chelmsford, MA (US)
Assigned to Raytheon Company, Arlington, VA (US)
Filed by RAYTHEON COMPANY, Waltham, MA (US)
Filed on Jul. 7, 2022, as Appl. No. 17/859,196.
Application 17/859,196 is a division of application No. 15/605,163, filed on May 25, 2017, granted, now 11,402,548.
Prior Publication US 2022/0350054 A1, Nov. 3, 2022
Int. Cl. G02B 1/14 (2015.01); C23C 14/08 (2006.01); C23C 14/10 (2006.01); C23C 14/35 (2006.01); F41G 7/22 (2006.01)
CPC G02B 1/14 (2015.01) [C23C 14/081 (2013.01); C23C 14/082 (2013.01); C23C 14/083 (2013.01); C23C 14/086 (2013.01); C23C 14/10 (2013.01); C23C 14/35 (2013.01); F41G 7/2253 (2013.01); F41G 7/2293 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method comprising:
providing an optical substrate formed of a Nanocomposite Optical Ceramic (NCOC) material including a first oxide nanograin material dispersed in a second oxide nanograin material; and
depositing a compressive layer of the NCOC material on a surface of the optical substrate;
wherein the compressive layer of the NCOC material has a microstructure different than a microstructure of the optical substrate;
wherein the microstructure of the compressive layer has a columnar polycrystalline grain structure with grain boundaries extending approximately perpendicular to the surface of the optical substrate; and
wherein the grain boundaries have a grain dimension extending away from the optical substrate that is larger than a grain dimension extending along the surface of the optical substrate, and wherein the grain dimension of the grain boundaries extending along the surface of the optical substrate is less than about one tenth of a wavelength of light to be transmitted through the compressive layer.