Head mounted display using a fused fiber bundle

• US 8,666,212 B1
• Filed: 01/06/2012
• Issued: 03/04/2014
• Est. Priority Date: 04/28/2011
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Amirparviz, Babak
• Primary Examiner(s): LEPISTO, RYAN A
• Application Number:
  US13/345,149
• Time in Patent Office: 788 Days
• Field of Search: 385/115, 385/119
• US Class Current: 385/119
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings

Abstract

An optical apparatus of a head mounted display includes a fused fiber bundle, an image source, and an image lens. The fused fiber bundle includes an array of fused optical fibers having an in-coupling surface located at a first end and an out-coupling surface physically facing an eye-ward direction and located at a second end. The fused fiber bundle is tapered such that the in-coupling surface has a larger surface area than the out-coupling surface to compress the light image. The image source is disposed at the first end of the fused fiber bundle and optically aligned with the in-coupling surface to launch the light image into the fused fiber bundle. The image lens is disposed at the second end and optically aligned with the out-coupling surface to focus the light image emitted from the second end towards an eye when the head mounted display is worn.

Claims

1. An optical apparatus of a head mounted display, the optical apparatus comprising:

a fused fiber bundle including an array of fused optical fibers having an in-coupling surface located at a first end for receiving a light image and an out-coupling surface physically facing an eye-ward direction and located at a second end for emitting the light image, wherein the fused fiber bundle is tapered such that the in-coupling surface has a larger surface area than the out-coupling surface to compress the light image and individual fiber diameters within the fused fiber bundle have smaller cross-sections at the out-coupling surface relative to the in-coupling surface;

an image source for generating the light image, the image source disposed at the first end of the fused fiber bundle and optically aligned with the in-coupling surface to launch the light image into the fused fiber bundle;

an image lens disposed at the second end of the fused fiber bundle and optically aligned with the out-coupling surface to focus the light image emitted from the second end towards an eye when the head mounted display is worn; and

a glasses structure, including;

a lens region positioned to align with the eye of a user when the glasses structure is worn by the user; and

an ear member coupled to the lens region and shaped to be supported by an ear of the user when worn by the user,

wherein the image source is mounted to the ear member and the fused fiber bundle extends from the image source to a central location within the lens region, the central location aligned with the eye of the user when the glasses structure is worn by the user.

2. The optical apparatus of claim 1, wherein the in-coupling surface of the fused fiber bundle substantially matches in size and profile shape to an image emission aperture of the image source.

3. The optical apparatus of claim 2, wherein the image emission aperture of the image source is abutted to the in-coupling surface of the fused fiber bundle.

4. The optical apparatus of claim 1, wherein the image lens comprises an electrically controlled variable lens for focusing the light image in a near-to-eye configuration.

5. The optical apparatus of claim 1, wherein each of the fused optical fibers have ion milled rough surface at the out-coupling surface to increase divergence of the light image emitted from the second end.

6. The optical apparatus of claim 1, wherein the fused fiber bundle is routed along a periphery of the lens region before crossing into the lens region to reach the central location.

7. The optical apparatus of claim 6,

wherein the fused fiber bundle is routed along the periphery of the lens region before bending by approximately 90 degrees to cross into the lens region to reach the central location, and

wherein the fused fiber bundle bends by approximately 90 degrees at the central location such that the out-coupling surface faces the eye-ward direction.

8. The optical apparatus of claim 1, further comprising:

a complementary lens disposed opposite to the image lens such that the out-coupling surface of the fused fiber bundle resides between the complementary lens and the image lens, the complementary lens having first optical properties that reverse second optical properties of the image lens.

9. The optical apparatus of claim 1, wherein fused fiber bundle is twisted at an intermediate location between the first and second ends to rotate an orientation of the light image between landscape and portrait orientations.

10. The optical apparatus of claim 1, further comprising:

a plurality of fused fiber bundles including the fused fiber bundle each guiding a copy of the light image into the lens region to emit the copy of the light image from different locations within the lens region to increase an eye box of the head mounted display; and

a plurality of image lenses each aligned with a corresponding out-coupling surface of the plurality of fused fiber bundles, wherein each of the image lenses is configured to position the copy of the light image substantially at infinity.

11. The optical apparatus of claim 10, further comprising:

an image replicator optically coupled to the image source and in-coupling surfaces of the plurality of fused fiber bundles to generate the copies of the light image for coupling into the in-coupling surfaces.

12. The optical apparatus of claim 1, further comprising:

a refractive material zone disposed between the out-coupling surface of the fused fiber bundle and the image lens, the refractive material zone having a refractive index other than air to affect a field of view of the light image upon emission from the out-coupling surface.

13. An optical apparatus of a head mounted display, the optical apparatus comprising:

a fused fiber bundle including an array of fused optical fibers having an in-coupling surface located at a first end for receiving a light image and an out-coupling surface physically facing an eye-ward direction and located at a second end for emitting the light image, wherein the fused fiber bundle is tapered such that the in-coupling surface has a larger surface area than the out-coupling surface to compress the light image and individual fiber diameters within the fused fiber bundle have smaller cross-sections at the out-coupling surface relative to the in-coupling surface;

an image source for generating the light image, the image source disposed at the first end of the fused fiber bundle and optically aligned with the in-coupling surface to launch the light image into the fused fiber bundle;

an image lens disposed at the second end of the fused fiber bundle and optically aligned with the out-coupling surface to focus the light image emitted from the second end towards an eye when the head mounted display is worn;

a refractive material zone disposed between the out-coupling surface of the fused fiber bundle and the image lens, the refractive material zone having a refractive index other than air to affect a field of view of the light image upon emission from the out-coupling surface, wherein the refractive material zone comprises a material having an electro-actively controlled index of refraction; and

a controller coupled to the refractive material zone to electro-actively control the refractive index of the refractive material zone.

14. A head mounted display comprising:

a pair of optical systems each including;

a fused fiber bundle including an array of fused optical fibers having an in-coupling surface located at a first end for receiving a light image and an out-coupling surface locating at a second end for emitting the light image, wherein the fused fiber bundle is tapered such that the in-coupling surface has a larger surface area than the out-coupling surface;

an image lens disposed at the second end of the fused fiber bundle and optically aligned with the out-coupling surface to focus the light image emitted from the second end; and

an image source for generating the light image and disposed at the first end of the fused fiber bundle and optically aligned with the in-coupling surface to launch the light image into the fused fiber bundle; and

a frame assembly to support the pair of optical systems for wearing on a head of a user, wherein each fused fiber bundle extends from a corresponding image source to a location aligned with a corresponding eye of the user and bends at the location such that the out-coupling surface of each of the optical systems physically faces an eye-ward direction when the head mounted display is worn by the user.

15. The head mounted display of claim 14, wherein the frame assembly comprises:

lens regions each positioned to align with the corresponding eye of the user when worn by the user; and

ear members coupled to the lens regions and shaped to be supported by ears of the user when the head mounted display is worn by the user,

wherein each image source is mounted to one of the ear members and each fused fiber bundle extends from the corresponding image source to the location within one of the lens regions, the location aligned with the corresponding eye of the user when the head mounted display is worn by the user.

16. The head mounted display of claim 15, wherein each fused fiber bundle is routed along a periphery of a corresponding lens region before crossing into the corresponding lens region to reach the location.

17. The head mounted display of claim 16,

wherein each fused fiber bundle is routed along the periphery of the corresponding lens region before bending by approximately 90 degrees to cross into the corresponding lens region to reach the location, and

wherein each fused fiber bundle bends by approximately 90 degrees at the location such that the out-coupling surface faces the eye-ward direction.

18. The head mounted display of claim 17, wherein each of the pair of optical systems further comprises:

a complementary lens disposed opposite to the image lens such that the out-coupling surface of the fused fiber bundle resides between the complementary lens and the image lens, the complementary lens having first optical properties that reverse second optical properties of the image lens to reduce a blind spot size associated with the image lens.

19. The head mounted display of claim 14, wherein each fused fiber bundle bends by approximately 90 degrees at the location such that the out-coupling surface faces the eye-ward direction.

20. A head mounted display comprising:

an optical system including;

a fused fiber bundle including an array of fused optical fibers having an in-coupling surface located at a first end for receiving a light image and an out-coupling surface locating at a second end for emitting the light image, wherein the fused fiber bundle is tapered such that the in-coupling surface has a larger surface area than the out-coupling surface;

an image lens disposed at the second end of the fused fiber bundle and optically aligned with the out-coupling surface to focus the light image emitted from the second end; and

an image source for generating the light image and disposed at the first end of the fused fiber bundle and optically aligned with the in-coupling surface to launch the light image into the fused fiber bundle; and

a frame assembly to support the optical system for wearing on a head of a user such that the out-coupling surface of the optical system physically faces an eye-ward direction when the head mounted display is worn by the user,

wherein the optical system further comprises;

a plurality of fused fiber bundles including the fused fiber bundle each guiding a copy of the light image into a lens region aligned with an eye of the user when the head mounted display is worn by the user to emit the copy of the light image from different locations within the lens region to increase an eye box of the head mounted display; and

a plurality of image lenses each aligned with a corresponding out-coupling surface of the plurality of fused fiber bundles.