Systems, devices, and methods for preventing eyebox degradation in a wearable heads-up display

Patent metadata

Field	Value
Publication number	US-2017219829-A1
Application number	US-201715415039-A
Country	US
Kind code	A1
Filing date	Jan 25, 2017
Priority date	Jan 29, 2016
Publication date	Aug 3, 2017
Grant date	—

Abstract

Systems, devices, and methods for preventing eyebox degradation in wearable heads-up displays (“WHUDs”) are described. A WHUD may provide an eyebox defined by multiple spatially-separated exit pupils, where the size of the eyebox is influenced by the spacing between the exit pupils. A larger eyebox is achieved with larger spacing between the exit pupils but a larger spacing between exit pupils is susceptible to the formation of gaps or blind spots in the eyebox (eyebox degradation) if bright environmental light causes the user's pupil to constrict to a size that is smaller than the spacing between the exit pupils. A material of variable chromism is included in the user's field of view to reduce the perceived brightness of environmental light and thereby prevent the user's pupil from constricting to a size smaller than the spacing between the exit pupils.

First claim

1 . A holographic combiner for use in a wearable heads-up display, the holographic combiner comprising:
an eyeglass lens; a holographic optical element carried by the eyeglass lens; and a material of variable chromism carried by the eyeglass lens.

2 . The holographic combiner of claim 1 wherein the holographic optical element includes a film of material selected from a group consisting of: photopolymer and silver halide.

3 . The holographic combiner of claim 1 wherein the holographic optical element includes at least one hologram.

4 . The holographic combiner of claim 3 wherein the at least one hologram is a fast-converging hologram that reflects light impingent thereon from a first range of incidence angles and converges the light to a point less than 3 cm from the holographic optical element.

5 . The holographic combiner of claim 1 wherein the holographic optical element includes a plurality of multiplexed holograms.

6 . The holographic combiner of claim 5 wherein the plurality of multiplexed holograms includes at least one hologram selected from a group consisting of: an angle-multiplexed hologram and a wavelength-multiplexed hologram.

7 . The holographic combiner of claim 1 wherein the eyeglass lens includes a prescription eyeglass lens.

8 . The holographic combiner of claim 1 wherein the material of variable chromism is selected from a group consisting of: a photochromic material, an electrochromic material, a thermochromic material, and a cathodochromic material.

9 . The holographic combiner of claim 1 wherein the material of variable chromism is variable between a first level of optical transparency and a second level of optical transparency, the first level of optical transparency greater than the second level of optical transparency.

10 . The holographic combiner of claim 9 wherein the material of variable chromism is continuously variable between the first level of optical transparency and the second level of optical transparency.

11 . The holographic combiner of claim 1 wherein the holographic optical element is carried on a first surface of the eyeglass lens and the material of variable chromism is carried on a second surface of the eyeglass lens, the second surface opposite the first surface across a thickness of the eyeglass lens.

12 . The holographic combiner of claim 11 wherein the eyeglass lens is curved, and wherein the holographic optical element is carried on an inner concave surface of the eyeglass lens and the material of variable chromism is carried on an outer convex surface of the eyeglass lens.

13 . The holographic combiner of claim 1 wherein at least one of the holographic optical element and the material of variable chromism is carried within the eyeglass lens.

14 . The holographic combiner of claim 1 wherein the eyeglass lens is optically transparent.

15 . A wearable heads-up display comprising:
a support structure that in use is worn on a head of a user; a scanning laser projector carried by the support structure; a holographic combiner carried by the support structure, wherein the holographic combiner is positioned within a field of view of an eye of the user when the support structure is worn on the head of the user, and wherein the holographic combiner comprises: an eyeglass lens; a holographic optical element carried by the eyeglass lens; and a material of variable chromism carried by the eyeglass lens.

16 . The wearable heads-up display of claim 15 wherein the holographic optical element of the holographic combiner receives light signals from the scanning laser projector and converges the light signals to multiple spatially-separated exit pupils at or proximate the eye of the user.

17 . The wearable heads-up display of claim 16 , further comprising an eyebox expander carried by the support structure and positioned in an optical path between the scanning laser projector and the holographic combiner, wherein the eyebox expander divides light from the scanning laser projector into multiple spatially-separated paths directed towards the holographic combiner to define the multiple spatially-separated exit pupils at or proximate the eye of the user.

18 . The wearable heads-up display of claim 15 wherein the material of variable chromism is variable between a first level of optical transparency and a second level of optical transparency, the first level of optical transparency greater than the second level of optical transparency.

19 . A method of preventing eyebox degradation in a wearable heads-up display, wherein the eyebox of the wearable heads-up display comprises multiple spatially-separated exit pupils at or proximate an eye of a user of the wearable heads-up display, the method comprising:
positioning a material of variable chromism in a field of view of the eye of the user; and varying an optical transparency of the material of variable chromism to compensate for variations in a brightness of an environmental light.

20 . The method of claim 19 wherein varying an optical transparency of the material of variable chromism in response to variations in a brightness of environmental light includes:
configuring the material of variable chromism with a first level of optical transparency while the brightness of the environmental light is at a first level of brightness; and
in response to the brightness of the environmental light changing from the first level of brightness to a second level of brightness, the second level of brightness brighter than the first level of brightness:
configuring the material of variable chromism with a second level of optical transparency, the second level of optical transparency less than the first level of optical transparency.

Assignees

• Thalmic Labs Inc

Inventors

• Bailey Matthew

Classifications

• G02B2027/0174

  holographic · CPC title

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title

• G02B2027/0105

  Holograms with particular structures · CPC title

• G02B2027/0118

  comprising devices for improving the contrast of the display / brillance control visibility · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title