SYSTEMS AND METHODS FOR MIXED REALITY

• US 20180374266A1
• Filed: 05/16/2018
• Published: 12/27/2018
• Est. Priority Date: 05/16/2017
• Status: Active Grant

• Current Assignee: Magic Leap, Inc.
• Original Assignee: Magic Leap, Inc.
• Inventors: Schowengerdt, Brian T., Watson, Mathew D., Tinch, David, Yeoh, Ivan Li Chuen, Macnamara, John Graham, Edwin, Lionel Ernest, Klug, Michael Anthony, Welch, William Hudson
• Granted Patent: US 10,755,481 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 2006/1215 Splitter
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 26/08 for controlling the direction of light in light guides G02B6/35
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/0944 Diffractive optical elements, e.g. gratings, holograms gratings per se G02B5/18; holograms used as optical elements per se G02B5/32
• CPC Class Codes: G02B 27/0955 Lenses lenses per se G02B3/00
• CPC Class Codes: G02B 27/0972 Prisms prisms per se G02B5/04
• CPC Class Codes: G02B 27/10 Beam splitting or combining systems polarising systems G02B27/28; mixing and splitting light signals using optical waveguides G02B6/28; beam shaping, e.g. changing the cross-sectional area, by dividing or superposing multiple light beams G02B27/0905
• CPC Class Codes: G02B 27/106 for splitting or combining a plurality of identical beams or images, e.g. image replication
• CPC Class Codes: G02B 27/30 Collimators
• CPC Class Codes: G02B 27/42 Diffraction optics , i.e. systems including a diffractive element being designed for providing a diffractive effectG02B27/60 takes precedence
• CPC Class Codes: G02B 5/18 Diffraction gratings holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44
• CPC Class Codes: G06T 19/006 Mixed reality object pose determination, tracking or camera calibration for mixed reality G06T7/00

Abstract

A virtual image generation system comprises a planar optical waveguide having opposing first and second faces, an in-coupling (IC) element configured for optically coupling a collimated light beam from an image projection assembly into the planar optical waveguide as an in-coupled light beam, a first orthogonal pupil expansion (OPE) element associated with the first face of the planar optical waveguide for splitting the in-coupled light beam into a first set of orthogonal light beamlets, a second orthogonal pupil expansion (OPE) element associated with the second face of the planar optical waveguide for splitting the in-coupled light beam into a second set of orthogonal light beamlets, and an exit pupil expansion (EPE) element associated with the planar optical waveguide for splitting the first and second sets of orthogonal light beamlets into an array of out-coupled light beamlets that exit the planar optical waveguide.

Claims

1. A virtual image generation system comprising:

a planar optical waveguide comprising a plurality of substrates including a primary substrate having a first thickness and at least a secondary substrate respectively having at least one second thickness, and at least one semi-reflective interface disposed between the substrates, the first thickness being at least twice each of the at least one second thickness;

an in-coupling (IC) element configured for optically coupling a collimated light beam from an image projection assembly for propagation as an in-coupled light beam within the planar optical waveguide, wherein the at least one semi-reflective interface is configured for splitting the in-coupled light beam into a plurality of primary light beamlets that propagate within the primary substrate; and

one or more diffractive optical elements (DOEs) associated with the planar optical waveguide for further splitting the plurality of primary light beamlets into an array of out-coupled light beamlets that exit a face of the planar optical waveguide.

2. The virtual image generation system of claim 1, wherein the first thickness is a non-multiple of each of the at least one second thickness.

3. The virtual image generation system of claim 1, wherein the at least one secondary substrate comprises a plurality of secondary substrates.

4. The virtual image generation system of claim 3, wherein at least two of the plurality of secondary substrates have second thicknesses that are substantially equal to each other.

5. The virtual image generation system of claim 3, wherein at least two of the plurality of secondary substrates have second thicknesses that are not substantially equal to each other.

6. The virtual image generation system of claim 5, wherein the first thickness is a non-multiple of at least one of the second thicknesses.

7. The virtual image generation system of claim 5, wherein at least two of the unequal second thicknesses are non-multiples of each other.

8. The virtual image generation system of claim 1, wherein the first thickness and the second thicknesses are selected, such that spacings between centers of at least two adjacent ones of the out-coupled light beamlets are equal to or less than a width of the collimated light beam.

9. The virtual image generation system of claim 1, wherein the first thickness and the second thicknesses are selected, such that no gap resides between edges of greater than half of adjacent ones of the out-coupled light beamlets.

10. The virtual image generation system of claim 1, wherein each of the at least one semi-reflective interface comprises a semi-reflective coating.

11. The virtual image generation system of claim 10, wherein the at least one semi-reflective coating are respectively disposed between the substrates via one of physical vapor deposition (PVD), ion-assisted deposition (IAD), and ion beam sputtering (IBS).

12. The virtual image generation system of claim 10, wherein each of the at least one semi-reflective coating is composed of one or more of a metal (Au, Al, Ag, Ni—

Cr, Cr and so on), dielectric (Oxides, Fluorides and Sulfides), and semiconductors (Si, Ge).

13. The virtual image generation system of claim 1, wherein adjacent ones of the plurality of substrates are composed of materials having different indices of refraction.

14. The virtual image generation system of claim 1, wherein the at least one semi-reflective interface is configured for splitting the in-coupled light beam into at least two in-coupled light beamlets, wherein the one or more DOEs comprises an orthogonal pupil expansion (OPE) element configured for respectively splitting the at least two in-coupled light beamlets into at least two sets of orthogonal light beamlets, the at least one semi-reflective interface is further configured for splitting the at least two sets of orthogonal light beamlets into at least four sets of orthogonal light beamlets, wherein the one or more DOEs comprises an exit pupil expansion (EPE) element configured for splitting the at least four sets of orthogonal light beamlets into the set of out-coupled light beamlets.

15. The virtual image generation system of claim 14, wherein the OPE element and EPE element are disposed on a face of the optical planar waveguide.

16. The virtual image generation system of claim 14, wherein the at least two in-coupled light beamlets propagate within the planar optical waveguide via total internal reflection (TIR) along a first optical path that intersects the OPE element, such that portions of the at least two in-coupled light beamlets are diffracted as the at least two sets of orthogonal light beamlets that propagate within the planar optical waveguide via TIR along second parallel optical paths.

17. The virtual image generation system of claim 16, wherein the second parallel optical paths are orthogonal to the first optical path.

18. The virtual image generation system of claim 16, wherein the at least two sets of orthogonal light beamlets intersect the EPE element, such that portions of the at least two sets of orthogonal light beamlets are diffracted as the out-coupled set of light beamlets out of the face of the planar optical waveguide.

19. The virtual image generation system of claim 14, wherein the EPE element is configured for imparting a convex wavefront profile on the out-coupled light beamlet array exiting the planar optical waveguide, the convex wavefront profile having a center of radius at a focal point to produce an image at a given focal plane.

20. The virtual image generation system of claim 1, wherein the collimated light beam defines an entrance pupil, and the out-coupled light beamlet array defines an exit pupil larger than the entrance pupil.

21. The virtual image generation system of claim 20, wherein the exit pupil is at least ten times larger than the entrance pupil.

22. The virtual image generation system of claim 20, wherein the exit pupil is at least one hundred times larger than the entrance pupil.

23. The virtual image generation system of claim 1, wherein the out-coupled light beamlet array is a two-dimensional out-coupled light beamlet array.

24. The virtual image generation system of claim 1, further comprising:

a display subsystem having an image projection assembly configured for generating the collimated light beam.

25. The virtual image generation system of claim 24, wherein the image projection assembly comprises a scanning device configured for scanning the collimated light beam.

26. A virtual image generation system comprising:

a planar optical waveguide having opposing first and second faces;

an in-coupling (IC) element configured for optically coupling a collimated light beam from an image projection assembly into the planar optical waveguide as an in-coupled light beam;

a first orthogonal pupil expansion (OPE) element associated with the first face of the planar optical waveguide for splitting the in-coupled light beam into a first set of orthogonal light beamlets;

a second orthogonal pupil expansion (OPE) element associated with the second face of the planar optical waveguide for splitting the in-coupled light beam into a second set of orthogonal light beamlets; and

an exit pupil expansion (EPE) element associated with the planar optical waveguide for splitting the first and second sets of orthogonal light beamlets into an array of out-coupled light beamlets that exit the planar optical waveguide.

27-40. -40. (canceled) cm 41. A virtual image generation system comprising:

a planar optical waveguide comprising a plurality of substrates including a primary substrate having a first thickness and at least two secondary substrates having second thicknesses, and at least two semi-reflective interfaces respectively disposed between the substrates;

an in-coupling (IC) element configured for optically coupling a collimated light beam from an image projection assembly for propagation as an in-coupled light beam within the planar optical waveguide, wherein the at least two semi-reflective interfaces are configured for splitting the in-coupled light beam into a plurality of primary light beamlets that propagate within the primary substrate; and

one or more diffractive optical elements (DOEs) associated with the planar optical waveguide for further splitting the plurality of primary light beamlets into an array of out-coupled light beamlets that exit a face of the planar optical waveguide.

42-66. -66. (canceled)

67. A virtual image generation system, comprising:

a pre-pupil expansion (PPE) element configured for receiving a collimated light beam from an imaging element and splitting the collimated light beam into a set of initial out-coupled light beamlets;

a planar optical waveguide;

an in-coupling (IC) element configured for optically coupling the set of initial out-coupled light beamlets into the planar optical waveguide as a set of in-coupled light beamlets; and

one or more diffractive elements associated with the planar optical waveguide for splitting the set of in-coupled light beamlets into a set of final out-coupled light beamlets that exit a face of the planar optical waveguide.

68-100. -100. (canceled)

101. A mixed reality system, comprising:

a light source configured to generate a virtual light beam; and

a light guiding optical element having an entry portion, an exit portion, a first light guiding optical sub-element, and a second light guiding optical sub-element,

wherein the first light guiding optical sub-element has a first thickness, and

wherein the second light guiding optical sub-element has a second thickness different from the first thickness.

102-119. -119. (canceled)

120. A mixed reality system, comprising:

a light source configured to generate a virtual light beam; and

a light guiding optical element having an entry portion, an exit portion, a first light guiding optical sub-element, and a second light guiding optical sub-element,

wherein the first light guiding optical sub-element has a first diffractive index, and

wherein the second light guiding optical sub-element has a second diffractive index different from the first diffractive index.

121-136. -136. (canceled)

137. A mixed reality system, comprising:

a light source configured to generate a virtual light beam; and

a light guiding optical element having an entry portion, an orthogonal pupil expander and a plurality of exit pupil expanders,

wherein the light source and the light guiding optical element are configured such that the virtual light beam;

(a) enters the light guiding optical element through the entry portion,

(b) propagates through the light guiding optical element by substantially total internal reflection,

(c) divides into a plurality of first virtual light beamlets by interacting with the orthogonal pupil expander, the plurality of first virtual light beamlets entering respective ones of the plurality of exit pupil expanders, and

(d) divides into a plurality of second virtual light beamlets by interacting with the plurality of exit pupil expanders,

wherein at least some of the plurality of second virtual light beamlets exit the light guiding optical element through the exit pupil expander.

138-147. -147. (canceled)

148. A mixed reality system, comprising:

a light source configured to generate a virtual light beam; and

a light guiding optical element having an entry portion, an orthogonal pupil expander and an exit portion,

wherein the light source and the light guiding optical element are configured such that the virtual light beam;

(a) enters the light guiding optical element through the entry portion,

(b) propagates through the light guiding optical element by substantially total internal reflection, and

(c) divides into a plurality of virtual light beamlets by interacting with the orthogonal pupil expander,

wherein at least some of the plurality of virtual light beamlets exit the light guiding optical element through the exit portion.

149-164. -164. (canceled)

165. A mixed reality system, comprising:

a light source configured to generate a virtual light beam; and

a light guiding optical element having an entry portion, an exit portion, a first light guiding optical sub-element, and a second light guiding optical sub-element,

wherein the first light guiding optical sub-element has a first light modifying characteristic, and

wherein the second light guiding optical sub-element has a second light modifying characteristic different from the first light modifying characteristic.