Eyepieces for augmented reality display system

An eyepiece waveguide for an augmented reality display system, the eyepiece waveguide comprising:

• an optically transmissive substrate;
• an input coupling grating (ICG) region formed on or in the substrate, the ICG region being configured to receive a set of input beams of light and to couple the set of input beams into the substrate as a set of guided beams, the set of guided beams being associated with a set of k-vectors in k-space which at least partially lies in a k-space annulus associated with the eyepiece waveguide, the k-space annulus corresponding to a region in k-space associated with guided propagation in the eyepiece waveguide;
• a multi-directional pupil expander (MPE) region formed on or in the substrate, the MPE region being positioned to receive the set of guided beams from the ICG region and being configured to diffract the set of guided beams so as to create at least three sets of diffracted beams, the sets of diffracted beams being associated with at least three sets of k-vectors which at least partially lie in the k-space annulus and are centered at three different angular locations;
• and
• an exit pupil expander (EPE) region formed on or in the substrate, the EPE region being positioned to receive one of the sets of diffracted beams from the MPE region and to out couple them from the optically transmissive substrate as output beams.

An eyepiece waveguide for an augmented reality display system, the eyepiece waveguide comprising:

• an optically transmissive substrate;
• an input coupling grating (ICG) region formed on or in the substrate, the ICG region being configured to:
• receive a set of input beams of light, the set of input beams being associated with a set of k-vectors in k-space;
• diffract the set of input beams so as to create a first guided set of beams and a first non-diffracted set of beams, the first guided set of beams corresponding to a translated subset of the k-vectors which lies inside a k-space annulus associated with the eyepiece waveguide, and the first non-diffracted set of beams corresponding to a translated subset of the k-vectors which lies outside the k-space annulus, the k-space annulus corresponding to a region in k-space associated with guided propagation in the eyepiece waveguide;
• diffract the set of input beams so as to create a separate second guided set of beams and a separate second non-diffracted set of beams, the second guided set of beams corresponding to a translated subset of the k-vectors which lies inside the k-space annulus, and the second non-diffracted set of beams corresponding to a translated subset of the k-vectors which lies outside the k-space annulus;
• a first pupil expander region formed on or in the substrate, the first pupil expander region being positioned to receive the first guided set of beams from the ICG region and being configured to replicate them as a first set of replicated beams;
• a second pupil expander region formed on or in the substrate, the second pupil expander region being positioned to receive the second guided set of beams from the ICG region and being configured to replicate them as a second set of replicated beams;
• and
• an exit region formed on or in the substrate, the exit region being positioned to receive the first and second sets of replicated beams, and the exit region being configured to out couple them as output beams, wherein the output beams represent the complete set of input beams.

An eyepiece waveguide for an augmented reality display system, the eyepiece waveguide comprising:

• an optically transmissive substrate;
• an input coupling grating (ICG) region formed on or in the substrate, the ICG region being configured to:
• receive a set of input beams of light, the set of input beams being associated with a set of k-vectors which form a field of view (FOV) shape in k-space, the FOV shape having a first dimension in k-space that is larger than the width of a k-space annulus associated with the eyepiece waveguide, the k-space annulus corresponding to a region in k-space associated with guided propagation in the eyepiece waveguide;
• and
• diffract the input beams so as to couple them into the substrate as guided beams and so as to translate the FOV shape to both a first position and a second position in the k-space annulus, wherein at the first position some of the FOV shape lies outside the k-space annulus and only a first sub-portion of the FOV shape lies inside the k-space annulus, and wherein at the second position some of the FOV shape lies outside the k-space annulus and only a second sub-portion of the FOV shape lies inside the k-space annulus;
• and
• a plurality of pupil expander regions formed on or in the substrate, the plurality of pupil expander regions being positioned to diffract the guided beams so as to translate the first and second sub-portions of the FOV shape to a third position in the k-space annulus where the complete FOV shape is reassembled.

An eyepiece waveguide for an augmented reality display system, the eyepiece waveguide comprising:

• an optically transmissive substrate;
• an input coupling grating (ICG) region formed on or in the substrate, the ICG region being configured to receive a set of input beams of light and to couple the set of input beams into the substrate as a set of guided beams, the set of input beams being associated with a set of k-vectors in k-space, the set of k-vectors having a first dimension in k-space that is larger than the width of a k-space annulus associated with the eyepiece waveguide, the k-space annulus corresponding to a region in k-space associated with guided propagation in the eyepiece waveguide;
• a plurality of pupil expander regions formed on or in the substrate, the plurality of pupil expander regions being positioned to collectively receive the guided beams from the ICG region and to diffract them so as to create a set of replicated beams;
• and
• an exit region formed on or in the substrate, the exit region being positioned to receive the replicated beams and to out couple the replicated beams from the optically transmissive substrate as a set of output beams which represents the complete set of input beams.

An eyepiece waveguide for an augmented reality display system, the eyepiece waveguide comprising:

• an optically transmissive substrate;
• an input coupling grating (ICG) region formed on or in the substrate, the ICG region comprising a diffraction grating configured to diffract a set of input beams of light corresponding to an input image into multiple diffractive orders, the diffraction grating having a period, Λ, which satisfies
• n
• 2
• ⁢
• ω
• c
• ≥
• 
• n
• 2
• Λ
• 
• >
• 1
• 2
• ⁢
• (
• n
• 2
• ⁢
• ω
• c
• +
• n
• 1
• ⁢
• ω
• c
• )
• ,
• where n2 is the refractive index of the optically transmissive substrate, n1 is the refractive index of a medium surrounding the optically transmissive substrate, ω is the angular frequency of the input beams of light, and c is the speed of light constant;
• a plurality of pupil expander regions formed on or in the substrate, the plurality of pupil expander regions being positioned to collectively receive the beams from the ICG region and to diffract them so as to create a set of replicated beams;
• and
• an exit region formed on or in the substrate, the exit region being positioned to receive the replicated beams and to out couple the replicated beams from the optically transmissive substrate as a set of output beams which represent the complete input image.