Durability coating for oxide films for metal fluoride optics

Patent metadata

Field	Value
Publication number	US-10295707-B2
Application number	US-201514623993-A
Country	US
Kind code	B2
Filing date	Feb 17, 2015
Priority date	Feb 27, 2014
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

A coated metal fluoride optic is provided. The coated metal fluoride optic includes an alkaline earth metal fluoride substrate and a coating disposed on at least one surface of the substrate. The coating includes an adhesion layer comprising a fluoride-containing material, a non-densified intermediate layer deposited on the adhesion layer, and a densified capping layer deposited on the intermediate layer.

First claim

What is claimed is:

1. A coated metal fluoride optic comprising:
an alkaline earth metal fluoride substrate; and
a coating disposed on at least one surface of the substrate, the coating comprising:
an adhesion layer comprising a fluoride-containing material;
a non-densified intermediate layer deposited on the adhesion layer, the non-densified intermediate layer comprising a material selected from the group consisting of SiO 2 , F—SiO 2 , Al 2 O 3 , F—Al 2 O 3 , SiON; and
a densified capping layer deposited on the non-densified intermediate layer, the densified capping layer having the same composition as the non-densified intermediate layer, the densified capping layer differing in density from the non-densified intermediate layer.

2. The coated metal fluoride optic of claim 1 , wherein the alkaline earth metal substrate is a single crystal alkaline earth metal fluoride substrate selected from the group consisting of MgF 2 , CaF 2 , BaF 2 , SrF 2 , and mixtures thereof.

3. The coated metal fluoride optic of claim 1 , wherein the alkaline earth metal substrate comprises a single crystal CaF 2 substrate doped with between about 12 ppm and about 2500 ppm MgF 2 .

4. The coated metal fluoride optic of claim 1 , wherein the fluoride-containing material of the adhesion layer is selected from the group consisting of AlF 3 , Na 3 AlF 6 , and MgF 2 .

5. The coated metal fluoride optic of claim 1 , wherein the fluoride-containing material of the adhesion layer has a refractive index of less than about 1.45.

6. The coated metal fluoride optic of claim 1 , wherein the fluoride-containing material of the adhesion layer has a CTE in the range of about 3.0×10 −6 /K and about 12×10 −6 /K.

7. The coated metal fluoride optic of claim 1 , wherein the adhesion layer has a thickness of between about 5.0 nm and about 70 nm.

8. The coated metal fluoride optic of claim 1 , wherein the intermediate layer has a thickness of between about 7.0 nm and about 20 nm.

9. The coated metal fluoride optic of claim 1 , wherein the capping layer comprises a material selected from the group consisting of SiO 2 , F—SiO 2 , Al 2 O 3 , F—Al 2 O 3 , SiON.

10. The coated metal fluoride optic of claim 1 , wherein the capping layer has a thickness of between about 40 nm and about 70 nm.

11. The coated metal fluoride optic of claim 1 , wherein the adhesion layer has a thickness of at least about 10 nm, and wherein transmission of 190-196 nm wavelength light through the metal fluoride optic is at least 93%.

12. The coated metal fluoride optic of claim 1 , wherein the adhesion layer has a thickness of at least about 30 nm, and wherein transmission of 190-196 nm wavelength light through the metal fluoride optic is at least 96%.

13. The coated metal fluoride optic of claim 1 , wherein the non-densified intermediate layer is in direct contact with the densified capping layer.

Assignees

• Corning Inc

Inventors

• Cox Gerald Philip
• D'Lallo Michael Joseph
• Oudard Jean-Francois
• Wang Jue

Classifications

• C23C14/024

  Deposition of sublayers, e.g. to promote adhesion of the coating (C23C14/027 takes precedence) · CPC title

• C30B25/00

  Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth · CPC title

• C23C14/0694

  Halides · CPC title

• C09D1/00

  Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances · CPC title

• Y10T428/265

  1 mil or less · CPC title