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

Abstract

Systems, devices, and methods for eyebox expansion by exit pupil replication in scanning laser-based wearable heads-up displays (“WHUDs”) are described. The WHUDs described herein each include a scanning laser projector (“SLP”), a holographic combiner, and an optical replicator positioned in the optical path therebetween. For each light signal generated by the SLP, the optical replicator receives the light signal and redirects each one of N>1 instances of the light signal towards the holographic combiner effectively from a respective one of N spatially-separated virtual positions for the SLP. The holographic combiner converges each one of the N instances of the light signal to a respective one 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.

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;   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   an optical replicator carried by the support structure and positioned in an optical path between the scanning laser projector and the holographic combiner, the optical replicator comprising at least one optical element arranged to receive a light signal generated by the scanning laser projector and redirect respective ones of N instances of the light signal towards the holographic combiner, where N is an integer greater than  1 , and wherein the holographic combiner comprises at least one hologram positioned and oriented to redirect each one of the N instances of the light signal towards the eye of the user.   
     
     
         2 . The wearable heads-up display of  claim 1  wherein the at least one hologram of the holographic combiner redirects the N instances of the light signal all spatially in parallel with one another towards respective regions of the eye of the user. 
     
     
         3 . The wearable heads-up display of  claim 1  wherein at least one optical element of the optical replicator is arranged to redirect respective ones of the N instances of the light signal towards the holographic combiner effectively from respective ones of N spatially-separated virtual positions for the scanning laser projector. 
     
     
         4 . The wearable heads-up display of  claim 1  wherein the support structure has a general shape and appearance of an eyeglasses frame. 
     
     
         5 . The wearable heads-up display of  claim 4 , further comprising:
 a prescription eyeglass lens, wherein the holographic combiner is carried by the prescription eyeglass lens.   
     
     
         6 . The wearable heads-up display of  claim 1  wherein the at least one hologram of the holographic combiner converges each one of the N instances of the light signal to a respective one of N exit pupils at or proximate the eye of the user. 
     
     
         7 . The wearable heads-up display of  claim 6  wherein the holographic combiner includes at least N multiplexed holograms, and wherein each one of the at least N multiplexed holograms converges a respective one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user. 
     
     
         8 . The wearable heads-up display of  claim 6  wherein:
 the scanning laser projector includes a red laser diode, a green laser diode, and a blue laser diode; and 
 the holographic combiner includes a wavelength-multiplexed holographic combiner that includes at least one red hologram, at least one green hologram, and at least one blue hologram, and wherein the at least one red hologram converges a respective red component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user, the at least one green hologram converges a respective green component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user, and the at least one blue hologram converges a respective blue component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user. 
 
     
     
         9 . The wearable heads-up display of  claim 8  wherein the holographic combiner includes a wavelength-multiplexed and angle-multiplexed holographic combiner that includes at least N angle-multiplexed red holograms, at least N angle-multiplexed green holograms, and at least N angle-multiplexed blue holograms, and wherein each one of the at least N angle-multiplexed red holograms converges a respective red component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user, each one of the at least N angle-multiplexed green holograms converges a respective green component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user, and each one of the at least N angle-multiplexed blue holograms converges a respective blue component of each one of the N instances of the light signal to a respective one of the N exit pupils at or proximate the eye of the user. 
     
     
         10 . The wearable heads-up display of  claim 1  wherein the optical path between the scanning laser projector and the holographic combiner includes a total scan range θ of the scanning laser projector, and wherein at least one optical element of the optical replicator is arranged to receive all light signals corresponding to a sweep of the total scan range θ by the scanning laser projector and redirect respective ones of N instances of all light signals corresponding to the sweep of the total scan range θ of the scanning laser projector towards the holographic combiner. 
     
     
         11 . The wearable heads-up display of  claim 1  wherein the light signal includes an image comprising at least two pixels. 
     
     
         12 . The wearable heads-up display of  claim 11  wherein each one of the N instances of the light signal includes a respective instance of the image. 
     
     
         13 . The wearable heads-up display of  claim 1  wherein each one of the N instances of the light signal includes a respective instance of a same pixel in a different instance of a same image.