WAVEGUIDES WITH LIGHT ABSORBING FILMS AND PROCESSES FOR FORMING THE SAME

• US 20180267312A1
• Filed: 03/06/2018
• Published: 09/20/2018
• Est. Priority Date: 03/14/2017
• Status: Active Grant

• Current Assignee: Magic Leap, Inc.
• Original Assignee: Magic Leap, Inc.
• Inventors: Melli, Mauro
• Granted Patent: US 10,852,542 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• CPC Class Codes: G02B 2027/0134 of stereoscopic type
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/003 Light absorbing elements
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area

Abstract

In some embodiments, a display device includes one or more waveguides having a vapor deposited light absorbing film on edges of the waveguide to mitigate ghost images. In some embodiments, the film is formed directly on the edge of the waveguide by a vapor deposition, such as an evaporative deposition process. In some embodiments, the light absorbing films may comprise carbon, for example carbon in the form of one or more allotropes of carbon, such as fullerenes, or black silicon.

Claims

1. An optical device comprising:

an optical waveguide comprising a first surface; and

a light absorber directly on at least the first surface, wherein the light absorber comprises a film comprising at least one of an allotrope of carbon and black silicon.

2. The optical device of claim 1, wherein the allotrope of carbon comprises one or more of carbon nanotubes, amorphous carbon, and fullerenes.

3. The optical device of claim 2, wherein the allotrope of carbon comprises fullerenes.

4. The optical device of claim 3, wherein the fullerenes are C₆₀.

5. The optical device of claim 1, wherein the optical waveguide is part of a waveguide stack.

6. The optical device of claim 1, wherein the optical waveguide further comprises incoupling optical elements and outcoupling optical elements on one or more major surfaces of the waveguide.

7. The optical device of claim 6, wherein the optical device is a head-mounted augmented reality display system, further comprising:

a spatial light modulator configured to output light having image content; and

an image injection device configured to inject the light having image content into the waveguide through the incoupling optical element,

wherein the outcoupling optical elements are configured to eject light propagating within the waveguide.

8. The optical device of claim 1, wherein the film has a thickness of greater than about 100 nm.

9. The optical device of claim 1, wherein the optical waveguide comprises a top major surface, a bottom major surface, and at least one edge surface, and wherein the first surface of the optical waveguide is the at least one edge surface.

10. The optical device of claim 1, wherein the optical waveguide comprises a light absorber on a second surface of the waveguide facing the first surface.

11. The optical device of claim 10, wherein the first and the second surfaces are edges of the waveguide.

12. A display device comprising:

an optical waveguide comprising first and second major surfaces and edge surfaces extending therebetween;

a spatial light modulator;

an image injection device configured to inject light from the spatial light modulator into the waveguide;

a light absorber on at least one edge surface,

wherein the light absorber comprises a film comprising at least one of an allotrope of carbon and silicon, and wherein the light absorber absorbs at least 70% of incident light having a wavelength ranging from 350 to 850 nm.

13. The optical device of claim 12, wherein the film comprises at least one of carbon nanotubes, amorphous carbon, fullerenes or black silicon.

14. The optical device of claim 12, wherein the light absorber absorbs at least 90% of incident light having a wavelength ranging from 350 to 850 nm.

15. A process for forming a light absorber on an optical waveguide, the process comprising:

providing the optical waveguide in a reaction chamber, the waveguide comprising a first surface;

forming a light absorbing film on the first surface, wherein forming the light absorbing film comprises;

contacting the first surface with airborne precursor species in the reaction chamber to deposit a thin film of the precursor species directly on the first surface,

wherein the thin film comprises at least one of an allotrope of carbon and silicon, and wherein the deposited thin film absorbs at least 70% of incident light having a wavelength ranging from 350 to 850 nm.

16. The process of claim 15, wherein the deposited thin film comprises fullerenes.

17. The process of claim 16, wherein the carbon thin film has a thickness of at least about 100 nm.

18. The process of claim 15, wherein the deposited thin film comprises black silicon.

19. The process of claim 15, wherein vapor depositing the thin film comprises:

evaporating a source material to form a vapor comprising a species of the source material; and

contacting at least the first surface of the at least one optical element with the vapor.

20. The process of claim 19, wherein the vapor comprises a powder.

21. The process of claim 20, wherein the powder comprises fullerenes.

22. The process of claim 15, wherein forming the light absorbing film further comprises:

etching the light absorbing film to form nanostructures in the film.