Anti-reflective coating for sapphire

Patent metadata

Field	Value
Publication number	US-10099247-B2
Application number	US-201615183055-A
Country	US
Kind code	B2
Filing date	Jun 15, 2016
Priority date	Jul 14, 2015
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

A coated substrate includes a sapphire substrate and an anti-reflective coating comprising a silicon-based material, wherein the anti-reflective coating has refractive index of 1.23 to 1.45 and a Mohs hardness of at least 4. A method of coating a sapphire substrate with an anti-reflective coating includes applying a liquid formulation to a sapphire substrate to form a coated substrate, and curing the coated substrate at a temperature of at least 500° C. to form an anti-reflective layer on the sapphire substrate.

First claim

The invention claimed is:

1. A coated substrate comprising:
a sapphire substrate;
an anti-reflective coating comprising a silicon-containing material, wherein the anti-reflective coating has refractive index of 1.23 to 1.45 and a Mohs hardness of at least 4, and wherein the silicon-containing material is formed from one or more crosslinkable organosiloxane oligomers by curing the crosslinkable siloxane oligomers at a temperature of at least 500° C. to form an anti-reflective layer on the sapphire substrate;
a layer comprising SiO 2 disposed over the anti-reflective coating; and
an anti-fingerprinting coating disposed over the layer comprising SiO 2 .

2. The coated substrate of claim 1 , wherein the coated substrate has a transmittance to light in the visible optical wavelength range from 380 to 800 nm of 90% or higher.

3. The coated substrate of claim 1 , wherein the anti-reflective coating has a thickness from 50 nm to 150 nm.

4. The coated substrate of claim 1 , wherein the anti-reflective coating has a water contact angle of less than 10°.

5. The coated substrate of claim 1 , wherein the one or more crosslinkable siloxane oligomers comprise methylsiloxane oligomers.

6. The coated substrate of claim 5 , wherein the methylsiloxane oligomers have a weight average molecular weight of 1000 Dalton to 5000 Dalton.

7. The coated substrate of claim 1 , wherein the anti-reflective coating is formed by curing the crosslinkable siloxane oligomers at a temperature of 500° C. to 800° C. for 3 minutes to 15 minutes.

8. The coated substrate of claim 1 , wherein the sapphire substrate has opposing first and second surfaces, the anti-reflective coating being in contact with the first surface of the sapphire substrate, the coated substrate further comprising a second anti-reflective coating in contact with the second surface of the sapphire substrate.

9. The coated substrate of claim 8 , wherein the second anti-reflective coating has refractive index of 1.23 to 1.45 and a Mohs hardness of at least 4.

10. The coated substrate of claim 1 , wherein the anti-reflective coating has a water contact angle of less than 10°, and the anti-fingerprinting coating has a water contact angle from 90° to 150°.

11. The coated substrate of claim 1 , wherein the anti-fingerprinting coating has an oleic acid contact angle from 60° to 90°.

12. A display, camera, lens, or optical equipment comprising the coated substrate of claim 1 .

13. A method of coating a sapphire substrate with an antireflective coating, the method comprising:
providing a sapphire substrate;
applying a liquid formulation to the substrate to form a coated substrate, wherein the liquid formulation comprises a crosslinkable silicon-based material and a solvent, wherein the crosslinkable silicon-containing material is formed from one or more cross linkable organosiloxane oligomers; and
curing the coated substrate at a temperature of at least 500° C. to form an anti-reflective layer on the sapphire substrate, the anti-reflective layer in the form of a coating having a refractive index of 1.23 to 1.45 and a Mohs hardness of at least 4;
applying a layer comprising SiO 2 over the anti-reflective layer; and
applying an anti-fingerprinting coating over the layer comprising SiO 2 .

14. The method of claim 13 , wherein said curing comprises heating the coated substrate at a temperature of at least 700° C.

15. The method of claim 13 , wherein the solvent is selected from the group consisting of water, ethanol, isopropyl alcohol, acetone, methanol, n-propanol, n-butanol, methyl ethyl ketone, diethyl ketone, butyl acetate, ethyl acetate, propylene glycol methyl ether acetate, and mixtures thereof.

16. The method of claim 13 , wherein the anti-reflective coating has a thickness from 50 nm to 150 nm.

17. The method of claim 13 , wherein the anti-reflective coating has a water contact angle of less than 10°.

18. The method of claim 13 , wherein the one or more crosslinkable siloxane oligomers comprise methylsiloxane oligomers.

19. The method of claim 13 , wherein the methylsiloxane oligomers have a weight average molecular weight of 1000 Dalton to 5000 Dalton.

Assignees

• Honeywell Int Inc

Inventors

• Duan Huifeng
• Shen Yanming
• Liu Ya Qun
• Huang Hong Min

Classifications

• G02B1/111 Primary

  using layers comprising organic materials · CPC title

• G02B1/14

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

• B05D1/005

  Spin coating · CPC title

• B05D3/0272 Primary

  with ovens · CPC title

• C23C18/1245

  Inorganic substrates other than metallic · CPC title