Systems, devices, and methods for waveguide-based eyebox expansion in wearable heads-up displays
Systems, devices, and methods for eyebox expansion in wearable heads-up displays (“WHUDs”) are described. The WHUDs described herein each include a projector and an optical waveguide positioned in an optical path between the projector and an eye of the user. For any given light signal from the projector, the optical waveguide receives the light signal at an input coupler and outputs multiple instances or copies of the light signal from multiple discrete, spatially-separated output couplers. The multiple instances or copies of the light signal may be converged by the optical waveguide directly to respective exit pupils at the user's eye or may be routed by the optical waveguide to a holographic combiner in the user's field of view from which the light signals may be converged to respective exit pupils at the user's eye. The optical waveguide employs exit pupil replication to expand the eyebox of the WHUD.
1. A wearable heads-up display comprising:
an eyeglass lens positioned in a field of view of an eye of a user when the wearable heads-up display is worn on a head of the user;
a projector to project light, the projector carried by an arm portion of the wearable heads-up display; and
an optical waveguide carried by the wearable heads-up display and positioned at least partially within the field of view of the eye of the user when the wearable heads-up display is worn on the head of the user, wherein the optical waveguide comprises:
an input coupler configured to couple light from the projector into the optical waveguide; and
an N number of output couplers arranged in an array having P>1 rows and Q>1 columns, wherein each respective output coupler of the N number of output couplers is oriented to couple a respective portion of light from the projector out of the optical waveguide and direct the respective portion of light to a respective one of N exit pupils at or proximate the eye of the user.
2. The wearable heads-up display of claim 1 , wherein:
each output coupler of the N number of output couplers is positioned within the field of view of the eye of the user when the wearable heads-up display is worn on the head of the user and oriented to converge the a respective portion of light directly towards a corresponding exit pupil at or proximate the eye of the user.
3. The wearable heads-up display of claim 2 , wherein:
the projector is carried by an arm portion of the wearable heads-up display and oriented to project light from the arm portion of the wearable heads-up display through free space to impinge on the input coupler; and
the input coupler is configured to couple the light into the optical waveguide.
4. The wearable heads-up display of claim 3 , wherein the input coupler is positioned within the field of view of the eye of the user when the wearable heads-up display is worn on the head of the user.
5. The wearable heads-up display of claim 1 , wherein:
the optical waveguide is positioned and oriented to guide a first portion of light and a second portion of light towards a first output coupler of the N number of output couplers; and
the first output coupler of the N number of output couplers is oriented to redirect the second portion of light towards a second output coupler of the N number of output couplers through the optical waveguide.
6. The wearable heads-up display of claim 5 , wherein the first output coupler is at least partially reflective of the first portion of light and at least partially transmissive of the second portion of light.
7. The wearable heads-up display of claim 1 , wherein the optical waveguide is integrated with the eyeglass lens.
8. The wearable heads-up display of claim 1 , wherein the optical waveguide includes at least one of an optical fiber or rectangular waveguide.
9. The wearable heads-up display of claim 1 , wherein the optical waveguide includes a transparent material.
10. The wearable heads-up display of claim 1 , wherein at least one of the input coupler and one or more output coupler of the N number of output couplers is selected from a group consisting of: an optical grating, a diffraction grating, a hologram, and a holographic optical element comprising at least two holograms.
11. The wearable heads-up display of claim 1 , wherein:
the optical waveguide includes a first optical channel through which a first portion of light is guided towards a first output coupler of the N number of output couplers and a second optical channel through which a second portion of light is guided towards a second output coupler of the N number of output couplers; and
the first portion of light is not guided through the second optical channel and the second portion of light is not guided through the first optical channel.
12. The wearable heads-up display of claim 2 , couple a respective portion of light from the projector out of the optical waveguide.
13. The wearable heads-up display of claim 12 , wherein:
each output coupler in each respective one of the P rows of the N number of output couplers are arranged in a row; and
each of at least Q−1 output couplers in each of the P rows is partially transmissive to transmit a respective portion of light from the projector through the optical waveguide towards at least one other one of the Q output couplers in the row.
14. The wearable heads-up display of claim 13 , wherein the optical waveguide includes P optical channels and each of the P rows corresponds to a respective one of the P optical channels.
15. The wearable heads-up display of claim 1 , wherein the projector includes a scanning laser projector.
16. The wearable heads-up display of claim 1 , wherein the wearable heads-up display has a general shape and appearance of an eyeglasses frame.
17. The wearable heads-up display of claim 1 , wherein the input coupler is a first input coupler, and further comprising a second input coupler oriented to couple light from the projector into the optical waveguide, wherein the first input coupler is positioned and oriented to couple a first portion of light from the projector into the optical waveguide and direct the first portion of light from the projector towards a first output coupler of the N number of output couplers and the second input coupler is positioned and oriented to couple a second portion of light from the projector into the optical waveguide and direct the second portion of light from the projector towards a second output coupler of the N number of output couplers.
18. A method comprising:
positioning an eyeglass lens of a wearable heads-up display such that the eyeglass lens is in a field of view of an eye of a user when the wearable heads-up display is worn on a head of the user;
disposing a projector configured to project light on an arm portion of the wearable heads-up display such that the projector is carried by an arm portion of the wearable heads-up display; and
arranging an optical waveguide of a wearable heads-up display such that the optical waveguide is carried by the wearable heads-up display and positioned at least partially within the field of view of the eye of the user when the wearable heads-up display is worn on the head of the user, wherein the optical waveguide comprises:
an input coupler configured to couple light from the projector into the optical waveguide; and
an N number of output couplers arranged in an array having P>1 rows and Q>1 columns, wherein each respective output coupler of the N number of output couplers is oriented to couple a respective portion of light from the projector out of the optical waveguide and direct the respective portion of light to a respective one of N exit pupils at or proximate the eye of the user.
19. A wearable heads-up display comprising:
an eyeglass lens positioned in a field of view of an eye of a user when the wearable heads-up display is worn on a head of the user;
a projector to project light, the projector carried by an arm portion of the wearable heads-up display; and
an optical waveguide integrated with the eyeglass lens and positioned at least partially within the field of view of the eye of the user when the wearable heads-up display is worn on the head of the user, wherein the optical waveguide comprises:
an input coupler configured to couple light from the projector into the optical waveguide; and
an N number of output couplers arranged in an array having P>1 rows and Q>1 columns, wherein each respective output coupler of the N number of output couplers is oriented to couple a respective portion of light from the projector out of the optical waveguide and direct the respective portion of light to a respective one of N exit pupils at or proximate the eye of the user.