Efficient thin curved eyepiece for see-through head wearable display

Patent metadata

Field	Value
Publication number	US-2016357016-A1
Application number	US-201514730983-A
Country	US
Kind code	A1
Filing date	Jun 4, 2015
Priority date	Jun 4, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

An eyepiece for a head wearable display includes a curved lightguide component, an input coupler, and an output coupler. The curved lightguide component guides display light received at an input region peripherally located from a viewing region and emits the display light along an eye-ward direction in the viewing region. The curved lightguide component includes an eye-ward facing surface that is concave and a world facing surface that is convex. The input coupler is disposed at the input region to couple the display light into the curved lightguide component. The output coupler is disposed at the viewing region to redirect the display light towards the eye-ward direction for output from the curved lightguide component. The output coupler is partially transmissive to ambient light incident through the world facing surface. The display light is guided between the input coupler and the output coupler entirely by total internal reflection.

First claim

What is claimed is:

1 . An eyepiece for a head wearable display, the eyepiece comprising:
a curved lightguide component for guiding display light received at an input region peripherally located from a viewing region and emitting the display light along an eye-ward direction in the viewing region, the curved lightguide component including:
an eye-ward facing surface that is concave; and
a world facing surface that is convex and opposite the eye-ward facing surface;
an input coupler disposed at the input region to couple the display light into the curved lightguide component; and an output coupler disposed at the viewing region to redirect the display light towards the eye-ward direction for output from the curved lightguide component, wherein the output coupler is partially transmissive to ambient light incident through the world facing surface such that the viewing region is see-through, wherein the display light is guided between the input coupler and the output coupler entirely by total internal reflection.

2 . The eyepiece of claim 1 , wherein the input coupler and the output coupler are configured to redirect light rays of the display light received from a single pixel of a display source along one of two different paths through the curved lightguide component such that a first group of the light rays encounters a different number of total internal reflections than a second group of the light rays.

3 . The eyepiece of claim 2 , wherein the first group of the light rays and the second group of the light rays stitch together at the viewing region to extend an eyebox from which the single pixel can be viewed.

4 . The eyepiece of claim 1 , wherein in the input coupler comprises a mirror having a first freeform surface and wherein the display light enters into the curved lightguide component through the eye-ward facing surface.

5 . The eyepiece of claim 1 , wherein the output coupler comprises a beam splitter having a second freeform surface, wherein the beam splitter is more transmissive than reflective to visible light.

6 . The eyepiece of claim 5 , further comprising a see-through add-on component disposed across the viewing region with the output coupler disposed along an interface between the see-through add-on component and the curved lightguide component, wherein the see-through add-on component and the curved lightguide component have a substantially same refractive index.

7 . The eyepiece of claim 6 , wherein the see-through add-on component has a thin portion and a thick portion and the curved lightguide component has a thin portion and a thick portion, wherein the thin portion of the see-through add-on component conformably mates to the thick portion of the curved waveguide component and wherein the thin portion of the curved waveguide component conformably mates to the thick portion of the see-through add-on component, wherein the output coupler is disposed at a transition from the thick portions to the thin portions of the see-through add-on component and the curved waveguide component.

8 . The eyepiece of claim 1 , wherein input coupler comprises an input surface molded into an end surface of the curved waveguide component that is not the eye-ward facing surface.

9 . The eyepiece of claim 1 , wherein the output coupler comprises array of prism structures disposed along the world facing surface.

10 . The eyepiece of claim 1 , wherein the output coupler comprises a hologram disposed along the world facing surface.

11 . The eyepiece of claim 1 , wherein the output coupler comprises first and second partial reflective minor segments disposed within the curved waveguide component to expand an eyebox of the display light, wherein the second partial reflective minor segment is disposed behind the first partial reflective minor segment such that the display light must pass through the first partial reflective mirror segment before reaching the second partial reflective minor segment.

12 . The eyepiece of claim 11 , wherein the first and second partial reflective minor segments are curved freeform surfaces.

13 . The eyepiece of claim 1 , wherein the eye-ward facing surface and the world facing surface of the curved lightguide component are both spherical surfaces.

14 . A head wearable display, comprising:
a display source to generate display light at a peripheral location; a curved lightguide component for guiding the display light to a viewing region offset from the peripheral location and emitting the display light along an eye-ward direction in the viewing region, the curved lightguide component including:
an eye-ward facing surface that is concave; and
a world facing surface that is convex and opposite the eye-ward facing surface;
an input coupler disposed at the input region to couple the display light into the curved lightguide component; an output coupler disposed at the viewing region to redirect the display light towards the eye-ward direction for output from the curved lightguide component, wherein the output coupler is partially transmissive to ambient light incident through the world facing surface such that the viewing region is see-through, wherein the display light is guided between the input coupler and the output coupler entirely by total internal reflection; and a frame assembly to support the curved lightguide component and the display source for wearing on a head of a user with the viewing region positioned in front of an eye of the user.

15 . The head wearable display of claim 14 , wherein the input coupler and the output coupler are configured to redirect light rays of the display light received from a single pixel of a display source along one of two different paths through the curved lightguide component such that a first group of the light rays encounters a different number of total internal reflections than a second group of the light rays.

16 . The head wearable display of claim 15 , wherein the first group of the light rays and the second group of the light rays stitch together at the viewing region to extend an eyebox from which the single pixel can be viewed.

17 . The head wearable display of claim 14 , wherein in the input coupler comprises a mirror having a first freeform surface and wherein the display light enters into the curved lightguide component through the eye-ward facing surface.

18 . The head wearable display of claim 14 , wherein the output coupler comprises a beam splitter having a second freeform surface, wherein the beam splitter is more transmissive than reflective to visible light.

19 . The head wearable display of claim 18 , further comprising a see-through add-on component disposed across the viewing region with the output coupler disposed along an interface between the see-through add-on component and the curved lightguide component, wherein the see-through add-on component and the curved lightguide component have a substantially same refractive index.

20 . The head wearable display of claim 14 , wherein input coupler comprises an input surface molded into an end surface of the curved waveguide component that is not the eye-ward facing surface.

21 . The head wearable display of claim 14 , wherein the output coupler comprises either one of an array of prism structures disposed along the world facing surface or a hologram disposed along the world facing surface.

22 . The head wearable display of claim 14 , wherein the output coupler comprises first and second partial reflective

Assignees

• Google Inc

Inventors

• Cakmakci Ozan
• Martinez Oscar A
• Dunphy James

Classifications

• G02B6/102

  for infrared and ultraviolet radiation · CPC title

• G02B2027/0125

  Field-of-view increase by wavefront division · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B2027/0138

  comprising image capture systems, e.g. camera · CPC title

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title