Systems, devices, and methods for eyebox expansion in wearable heads-up displays

Patent metadata

Field	Value
Publication number	US-10274736-B2
Application number	US-201815971796-A
Country	US
Kind code	B2
Filing date	May 4, 2018
Priority date	Feb 17, 2015
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

Systems, devices, and methods for eyebox expansion by exit pupil replication in wearable heads-up displays (“WHUDs”) are described. A WHUD includes a scanning laser projector (“SLP”), a holographic combiner, and an optical splitter positioned in the optical path therebetween. The optical splitter receives light signals generated by the SLP and separates the light signals into N sub-ranges based on the point of incidence of each light signal at the optical splitter. The optical splitter redirects the light signals corresponding to respective ones of the N sub-ranges towards the holographic combiner effectively from respective ones of N spatially-separated virtual positions for the SLP. The holographic combiner converges the light signals to respective ones of N spatially-separated exit pupils at the eye of the user. In this way, multiple instances of the exit pupil are distributed over the area of the eye and the eyebox of the WHUD is expanded.

First claim

The invention claimed is:

1. 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, wherein the scanning laser projector includes a red laser diode, a green laser diode, and a blue laser diode;
a holographic combiner carried by the support structure, wherein the holographic combiner comprises a red hologram, a green hologram, and a blue hologram, and 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
an optical splitter carried by the support structure and positioned in an optical path between the scanning laser projector and the holographic combiner, the optical splitter arranged to receive light signals generated by the scanning laser projector and redirect the light signals towards the holographic combiner effectively from N spatially-separated virtual positions for the scanning laser projector, where N is an integer greater than 1, the holographic combiner arranged to receive the light signals from the optical splitter and to converge the light signals to N exit pupils at the eye of the user, a particular one of the N exit pupils to which a light signal is converged determined by a particular virtual position for the scanning laser projector from which the light signal is redirected by the optical splitter, and wherein the red hologram is positioned and oriented to converge red components of the light signals to the N exit pupils, the green hologram is positioned and oriented to converge green components of the light signals to the N exit pupils, and the blue hologram is positioned and oriented to converge blue components of the light signals to the N exit pupils.

2. The wearable heads-up display of claim 1 wherein the scanning laser projector has a total two-dimensional scan range θ and the optical splitter is arranged to separate the total two-dimensional scan range θ of the scanning laser projector into N two-dimensional sub-ranges φ 1 , where Σ i=1 N φ i =θ, and wherein each one of the N sub-ranges φ i corresponds to a respective one of the N spatially-separated virtual positions for the scanning laser projector.

3. The wearable heads-up display of claim 2 wherein the optical splitter is arranged to:
receive light signals corresponding to a sweep of the total two-dimensional scan range θ by the scanning laser projector;
separate the light signals corresponding to the sweep of the total two-dimensional scan range θ into the N two-dimensional sub-ranges φ i ; and
redirect the light signals corresponding to the sweep of the total two-dimensional scan range θ towards the holographic combiner effectively from each of the N spatially-separated virtual positions for the scanning laser projector, a particular virtual position for the scanning laser projector from which each light signal in the sweep of the total two-dimensional scan range θ is redirected by the optical splitter determined by a particular two-dimensional sub-range φ i to which the light signal corresponds.

4. The wearable heads-up display of claim 1 wherein the scanning laser projector has a total scan range Ω in a first dimension, where 0°<Ω<180°, and the optical splitter is arranged to separate the total scan range Ω of the scanning laser projector in the first dimension into X sub-ranges ω i in the first dimension, where 1<X≤N and Σ i=1 X ω i =Ω, and wherein each one of the X sub-ranges ω i corresponds to a different one of the N spatially-separated virtual positions for the scanning laser projector.

5. The wearable heads-up display of claim 4 wherein the optical splitter is arranged to:
receive light signals corresponding to a sweep of the total scan range Ω in the first dimension by the scanning laser projector;
separate the light signals corresponding to the sweep of the total scan range Ω in the first dimension into the X sub-ranges ω i in the first dimension; and
redirect the light signals corresponding to the sweep of the total scan range Ω in the first dimension towards the holographic combiner effectively from at least X of the N spatially-separated virtual positions for the scanning laser projector, a particular virtual position for the scanning laser projector from which each light signal in the sweep of the total scan range Ω in the first dimension is redirected by the optical splitter determined by a particular sub-range ω i in the first dimension to which the light signal corresponds.

6. The wearable heads-up display of claim 4 wherein the scanning laser projector has a total scan range ψ in a second dimension, where 0°<ψ<180°, and the optical splitter is arranged to separate the total scan range ψ of the scanning laser projector in the second dimension into Y sub-ranges β i in the second dimension, where 1<Y≤N and Σ i=1 Y β i =ψ, and wherein each one of the Y sub-ranges β i corresponds to a different one of the N spatially-separated virtual positions for the scanning laser projector.

7. The wearable heads-up display of claim 6 wherein the optical splitter is arranged to:
receive light signals corresponding to a sweep of the total scan range ψ in the second dimension by the scanning laser projector;
separate the light signals corresponding to the sweep of the total scan range ψ in the second dimension into the Y sub-ranges β i in the second dimension; and
redirect the light signals corresponding to the sweep of the total scan range ψ in the second dimension towards the holographic combiner effectively from at least Y of the N spatially-separated virtual positions for the scanning laser projector, a particular virtual position for the scanning laser projector from which a light signal in the sweep of the total scan range ψ in the second dimension is redirected by the optical splitter determined by a particular sub-range β i in the second dimension to which the light signal corresponds.

8. The wearable heads-up display of claim 1 wherein the support structure has a general shape and appearance of an eyeglasses frame.

9. The wearable heads-up display of claim 8 , further comprising a prescription eyeglass lens, wherein the holographic combiner is carried by the prescription eyeglass lens.

10. The wearable heads-up display of claim 1 wherein:
the holographic combiner is arranged to receive the light signals from the optical splitter and to converge the light signals to respective ones of N exit pupils at the eye of the user, a particular one of the N exit pupils to which a light signal is converged determined by a particular virtual position for the scanning laser projector from which the light signal is redirected by the optical splitter;
the red hologram is positioned and oriented to converge red components of the light signals to respective ones of the N exit pupils;
the green hologram is positioned and oriented to converge green components of the light signals to respective ones of the N exit pupils; and
the blue hologram is positioned and oriented to converge blue components of the light signals to respective ones of the N exit pupils.

11. The wearable heads-up display of claim 1 wherein:
the red hologram is positioned and oriented to converge red components of light signals redirected from each respective one of the N spatially-separated virtual positions for the scanning laser projector by the optical splitter to respective ones of the N exit pupils;
the green hologram is positioned and oriented to converge green components of light signals redirected from each respective one of the N spatially-separated virtual positions for the scanning laser projector by the optica

Assignees

• Thalmic Labs Inc
• North Inc

Inventors

• Alexander Stefan
• Bailey Matthew
• Morrison Vance R
• Holland Lloyd Frederick
• Moore Joshua

Classifications

• G03H2001/266

  Wavelength multiplexing · CPC title

• G02B27/017

  Head mounted · CPC title

• G02B2027/0123

  comprising devices increasing the field of view · CPC title

• G03H1/265

  Angle multiplexing; Multichannel holograms (G03H1/268 takes precedence) · CPC title

• G09G3/001

  using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background (slide projectors per se G03B23/00 = 42 HP) · CPC title