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Patent metadata

Field	Value
Publication number	US-9575316-B2
Application number	US-201414526531-A
Country	US
Kind code	B2
Filing date	Oct 29, 2014
Priority date	Oct 29, 2014
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

This disclosure relates to an optical system and a method for its manufacture. One embodiment of the optical system may include an optical material upon which a multilayer stack may be deposited. The multilayer stack may include a first layer composed on a first surface of the optical material, a second layer composed on the first layer, and a third layer composed on the second layer. Among other possibilities, the first layer may include Al 2 O 3 , the second layer may include Al, and the third layer may include SiO 2 . The multilayer stack may be a reflective coating on a surface of the optical material with optical power. Thus, the reflective coating may serve as a reflective image former within the optical system. The optical system may be configured as a head-mountable device.

First claim

What is claimed is:

1. An optical system, comprising:
an image former configured to form a virtual image from a light pattern, wherein the image former comprises:
a first layer composed on a first surface of an optical material, wherein the first surface comprises a finite radius of curvature;
a second layer composed on the first layer; and
a third layer composed on the second layer, wherein the first layer comprises Al 2 O 3 , the second layer comprises Al, and the third layer comprises SiO 2 .

2. The optical system of claim 1 wherein the optical system is configured as a head-mountable device and wherein the optical system further comprises: a beam splitter through which outside light and the virtual image are visible, and a light source configured to generate the light pattern.

3. The optical system of claim 1 wherein the optical material is Zeonex E-48R.

4. The optical system of claim 1 wherein the first layer further comprises a first layer thickness between 20 nm and 30 nm of Al 2 O 3 .

5. The optical system of claim 1 wherein the second layer further comprises a second layer thickness between 90 nm and 110 nm of Al.

6. The optical system of claim 1 wherein the third layer further comprises a third layer thickness between 140 nm and 160 nm of SiO 2 .

7. The optical system of claim 1 wherein a combination of the first, second, and third layers comprise an overall layer thickness between 250 nm and 300 nm.

8. The optical system of claim 2 wherein a combination of the first, second, and third layers comprise a concave mirror with respect to the light pattern generated by the light source.

9. The optical system of claim 8 wherein the combination of the first, second, and third layers further comprises an edge slope wherein the edge slope is less than 100 nanometers per 100 microns as measured from an edge of the first surface.

10. A method of manufacturing an optical system, comprising:
providing an optical system comprising:
an optical material having a first surface, wherein the first surface comprises a finite radius of curvature; and
a light source optically coupled to the optical material and configured to generate a light pattern;

forming a first layer on the first surface of the optical material, wherein the first layer comprises Al 2 O 3 ;
forming a second layer on the first layer, wherein the second layer comprises Al; and
forming a third layer on the second layer, wherein the third layer comprises SiO 2 , wherein a combination of the first, second, and third layers comprise an overall thickness wherein the overall thickness is between 250 nm and 300 nm.

11. The method of manufacturing an optical system of claim 10 wherein the optical system is configured to operate as a head-mountable device and further comprising a beam splitter optically coupled to the optical material and through which outside light is visible.

12. The method of manufacturing an optical system of claim 10 wherein the optical material comprises Zeonex E-48R.

13. The method of manufacturing an optical system of claim 10 wherein forming the first layer further comprises depositing the first layer with a first layer thickness between 20 nm and 30 nm of Al 2 O 3 .

14. The method of manufacturing an optical system of claim 10 wherein forming the second layer further comprises depositing the second layer with a second layer thickness between 90 nm and 110 nm of Al.

15. The method of manufacturing an optical system of claim 10 wherein forming the third layer further comprises depositing the third layer with a third layer thickness between 140 nm and 160 nm of SiO 2 .

16. The method of manufacturing an optical system of claim 10 wherein forming the first, second, and third layers comprises depositing the respective layers using a physical vapor deposition technique.

17. The method of manufacturing an optical system of claim 10 wherein forming the first, second, and third layers comprises depositing the respective layers using an atomic layer deposition technique.

18. The method of manufacturing an optical system of claim 10 wherein a combination of the first, second, and third layers further comprises an edge slope wherein the edge slope is less than 100 nanometers per 100 microns as measured from an edge of the first surface.

19. The optical system of claim 1 wherein the first surface is spherically curved.

20. The method of manufacturing an optical system of claim 10 wherein the first surface is spherically curved.

Assignees

• Google Inc

Inventors

• Bahmandar Ali-Reza
• Martinez Oscar Luis
• Baldwinson Michael
• Kamath Ajay

Classifications

• C23C16/402

  Silicon dioxide · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B1/12

  by surface treatment, e.g. by irradiation · CPC title

• C23C16/403

  of aluminium, magnesium or beryllium · CPC title

• C23C14/10

  Glass or silica · CPC title