Durability coating for oxide films for metal fluoride optics

Patent metadata

Field	Value
Publication number	US-2015241605-A1
Application number	US-201514623993-A
Country	US
Kind code	A1
Filing date	Feb 17, 2015
Priority date	Feb 27, 2014
Publication date	Aug 27, 2015
Grant date	—

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; and
a densified capping layer deposited on the 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 comprises a material selected from the group consisting of SiO 2 , F—SiO 2 , Al 2 O 3 , F—Al 2 O 3 , SiON.

9 . 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.

10 . 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.

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

12 . 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%.

13 . 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%.

14 . A method for forming a coated metal fluoride optic, the method comprising:
depositing an adhesion layer comprising a fluoride-containing material onto at least one face of an alkaline earth metal fluoride substrate; depositing an intermediate layer onto the adhesion layer without plasma ion assistance; and depositing a capping layer onto the intermediate layer with plasma ion assistance.

15 . The method of claim 14 , wherein the depositing steps comprise depositing at a temperature of between about 280° C. and about 350° C.

16 . The method of claim 15 , wherein the depositing steps comprise depositing at a temperature of between about 300° C. and about 325° C.

17 . The method of claim 14 , 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 .

18 . The method of claim 14 , wherein the fluoride-containing material of the adhesion layer has a refractive index of less than about 1.45.

19 . The method of claim 14 , wherein the intermediate 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.

20 . The method of claim 14 , 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.

Assignees

• Corning Inc

Inventors

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

Classifications

• G02B1/115 Primary

  Multilayers · CPC title

• C09D1/00

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

• G02B1/14 Primary

  Protective coatings, e.g. hard coatings · CPC title

• C23C14/0694

  Halides · CPC title

• C30B25/00

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