Waveguide with embedded mirrors

• US 8,743,464 B1
• Filed: 11/03/2010
• Issued: 06/03/2014
• Est. Priority Date: 11/03/2010
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Amirparviz, Babak
• Primary Examiner(s): Pham, Thomas K
• Assistant Examiner(s): Patel, Vipin
• Application Number:
  US12/938,669
• Time in Patent Office: 1,308 Days
• Field of Search: 359/15, 359/315, 359/317, 359/618, 359/629, 359/630, 359/633, 359/634.637, 359/65, 349/65, 345 6- 8
• US Class Current: 359/633
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 2027/015 involving arrangement aiming to get less bulky devices
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/09 Multifaceted or polygonal mirrors , e.g. polygonal scanning mirrors; Fresnel mirrors

Abstract

A waveguide with embedded mirrors includes an in-coupling region for receiving input light into the waveguide and an out-coupling region for emitting output light from the waveguide. The mirrors include a plurality of in-coupling mirrors disposed within the in-coupling region of the waveguide and orientated to reflect the input light down the waveguide towards the out-coupling region as guided light. The mirrors further include a plurality of out-coupling mirrors disposed within the out-coupling region of the waveguide and orientated to reflect the guided light out of the waveguide as the output light.

Claims

1. An apparatus, comprising:

a waveguide including an in-coupling region for receiving input light into the waveguide and an out-coupling region for emitting output light from the waveguide;

a plurality of in-coupling mirrors disposed within the in-coupling region of the waveguide and orientated to reflect the input light down the waveguide towards the out-coupling region as guided light, wherein the in-coupling mirrors are laterally offset from one another within the in-coupling region to each reflect a different lateral portion of the input light while not reflecting the different lateral portions of the input light directed to other in-coupling mirrors; and

a plurality of out-coupling mirrors disposed within the out-coupling region of the waveguide and orientated to reflect the guided light out of the waveguide as the output light, wherein the out-coupling mirrors each include;

a first reflective surface orientated to reflect the guided light as the output light for emission from the out-coupling region; and

a second reflective surface obliquely angled relative to the first reflective surface and orientated to reflect the guided light for propagation further down the out-coupling region of the waveguide, wherein the first and second reflective surfaces are reflective, non-optically transmissive surfaces,

wherein the out-coupling mirrors are offset from one another such that the out-coupling region comprises a partially transparent region permitting external light to pass through the out-coupling region between the out-coupling mirrors.

2. The apparatus of claim 1, wherein the waveguide includes an intermediate region disposed between the in-coupling region and the out-coupling region for guiding the guided light between the in-coupling region and the out-coupling region.

3. The apparatus of claim 2, wherein the intermediate region guides the guided light at least partially by total internal reflection.

4. The apparatus of claim 2, wherein the intermediate region includes at least one metallic reflective layer disposed along a side of the intermediate region and wherein the intermediate region guides the guided light at least partially by reflection off of the metallic reflective layer.

5. The apparatus of claim 1, wherein the in-coupling mirrors and the out-coupling mirrors each comprise structures having flat reflective surfaces, wherein the structures of the out-coupling mirrors are offset from one another each for reflecting a different portion of the guided light.

6. The apparatus of claim 5, wherein the flat reflective surfaces of the in-coupling and out-coupling mirrors are reflective, non-optically-transmissive surfaces.

7. The apparatus of claim 1, wherein the in-coupling mirrors each comprise a structure disposed within the waveguide having a substantially triangular cross-section with a reflective surface orientated to form an oblique angle to a light incident side of the in-coupling region.

8. The apparatus of claim 7, wherein the in-coupling mirrors are disposed along a planar surface of the in-coupling region of the waveguide.

9. The apparatus of claim 1, wherein the first reflective surface is orientated to form an oblique angle with a surface of the waveguide where the output light emerges from the out-coupling region and wherein the second reflective surface is orientated substantially parallel to the surface of the out-coupling region where the output light emerges.

10. The apparatus of claim 1, further comprising at least one of a light absorbing surface, an anti-reflective surface, or a light scattering surface disposed on an end region of the waveguide adjacent to the out-coupling region to inhibit the guided light from reflecting back down the waveguide towards the in-coupling region.

11. The apparatus of claim 1, wherein the waveguide comprises a polymer material.

12. The apparatus of claim 1, wherein there is a same number of the in-coupling mirrors as there is of the out-coupling mirrors.

13. The apparatus of claim 1, wherein the in-coupling mirrors are the first reflective surfaces in a path of the input light after entering into the waveguide.

14. An optical system for rendering an augmented reality to a user, the optical system comprising:

a waveguide including;

an in-coupling region for receiving input light and an out-coupling region for emitting output light;

a plurality of in-coupling mirrors disposed within the in-coupling region and orientated to reflect the input light towards the out-coupling region as guided light, wherein the in-coupling mirrors are laterally offset from one another within the in-coupling region to each reflect a different lateral portion of the input light, wherein the in-coupling mirrors are non-optically transmissive surfaces to the input light; and

a plurality of out-coupling mirrors disposed within the out-coupling region and orientated to reflect the guided light out of the waveguide to an eye of the user as the output light, wherein the out-coupling mirrors are reflective, non-optically transmissive surfaces, wherein the out-coupling mirrors are offset from one another such that the out-coupling region comprises a partially transparent region permitting external light to pass through the out-coupling region between the out-coupling mirrors;

an image source positioned to launch a computer generated image into the in-coupling region of the waveguide; and

a frame assembly to support the waveguide and the image source for wearing on a head of the user.

15. The optical system of claim 14, wherein the in-coupling mirrors and the out-coupling mirrors each comprise structures having flat reflective surfaces, wherein the structures of the in-coupling mirrors are offset from one another each for reflecting a different portion of the input light, wherein the structures of the out-coupling mirrors are offset from one another each for reflecting a different portion of the guided light.

16. The optical system of claim 14, wherein the in-coupling mirrors are disposed along a planar surface of the in-coupling region of the waveguide.

17. The optical system of claim 14, wherein the out-coupling mirrors each comprise:

a first reflective surface orientated to form an oblique angle with a surface of the waveguide where the output light emerges from the out-coupling region; and

a second reflective surface orientated substantially parallel to the surface of the out-coupling region where the output light emerges.

18. The optical system of claim 14, wherein there is a same number of the in-coupling mirrors as there is of the out-coupling mirrors.

19. A method of displaying a near-to-eye image, the method comprising:

receiving input light into an in-coupling region of a waveguide;

reflecting different portions of the input light with a corresponding plurality of in-coupling mirrors disposed within the in-coupling region of the waveguide, wherein the in-coupling mirrors are laterally offset from one another within the in-coupling region to each reflect a different lateral portion of the input light, wherein the in-coupling mirrors are non-transmissive to the input light;

guiding the input light reflected off the in-coupling mirrors as guided light guided towards an out-coupling region of the waveguide;

reflecting different portions of the guided light with a corresponding plurality of out-coupling mirrors disposed within the out-coupling region of the waveguide for emission from the out-coupling region as output light, wherein the out-coupling mirrors are reflective, non-optically transmissive surfaces; and

passing external light through the out-coupling region between the out-coupling mirrors, wherein the out-coupling mirrors are offset from one another such that the out-coupling region comprises a partially transparent region to the external light.

20. The method of claim 19, wherein the input light and the output light is collimated.

21. The method of claim 19, wherein the in-coupling mirrors and the out-coupling mirrors each comprise structures having flat reflective surfaces, wherein the structures of the in-coupling mirrors are offset from one another each for reflecting a different portion of the input light, wherein the structures of the out-coupling mirrors are offset from one another each for reflecting a different portion of the guided light.

22. The method of claim 21, wherein the flat reflective surfaces of the in-coupling and out-coupling mirrors are reflective, non-optically-transmissive surfaces.

23. The method of claim 19, wherein reflecting different portions of the guided light with the plurality of out-coupling mirrors comprises:

reflecting a first portion of the guided light off of first reflective surfaces orientated to form an oblique angle with a surface of the waveguide where the output light emerges from the out-coupling region, the first portion for immediate emission from the waveguide; and

reflecting a second portion of the guided light off of second reflective surfaces orientated substantially parallel to the surface of the out-coupling region where the output light emerges, the second portion for propagating further down the out-coupling region prior to emerging from the waveguide as the output light.

24. An apparatus, comprising:

a waveguide including an in-coupling region for receiving input light into the waveguide and an out-coupling region for emitting output light from the waveguide;

a plurality of in-coupling mirrors disposed within the in-coupling region of the waveguide and orientated to reflect the input light down the waveguide towards the out-coupling region as guided light; and

a plurality of out-coupling mirrors disposed within the out-coupling region of the waveguide and orientated to reflect the guided light out of the waveguide as the output light, wherein the out-coupling mirrors each include;

a first reflective surface orientated to reflect the guided light as the output light for emission from the out-coupling region; and

a second reflective surface obliquely angled relative to the first reflective surface and orientated to reflect the guided light for propagation further down the out-coupling region of the waveguide, wherein the second reflective surface is disposed internal to the waveguide and offset from an external side surface of the waveguide,

wherein the plurality of out-coupling mirrors are laterally offset from each other with intervening gaps between adjacent out-coupling mirrors such that the second reflective surface of each of the out-coupling mirrors is separate from the second reflective surface of other out-coupling mirrors,

wherein the out-coupling mirrors are reflective, non-optically transmissive surfaces and are offset from one another such that the out-coupling region comprises a partially transparent region permitting external light to pass through the out-coupling region in the intervening gaps between the out-coupling mirrors.