Waveguide irradiator

Abstract

An optical system for an augmented reality head mounted display eyepiece, the optical system configured to deliver an image to an eye, where the optical system includes an optical device. The optical device is arranged to receive light output from the light source. The optics are further arranged relative to the spatial light modulator such that light received from the light source propagates through the optics and illuminates the spatial light modulator. Light illuminating the spatial light modulator is redirected back through the optics and coupled into the at least one waveguide through the at least one coupling-in optical element. At least a portion of the coupled light exits from the at least one waveguide through the at least one outcoupling optical element and is directed to the eye of the user.

Description

[0001] This application is a divisional application of the Chinese patent application "Waveguide Illuminator" with application number 201880086397.7 (filing date: December 10, 2018).

[0002] Cross - reference to related applications

[0003] This application claims the benefit of priority of the U.S. Provisional Patent Application No. 62 / 597,359, entitled "WAVEGUIDE ILLUMINATOR", filed on December 11, 2017, and the U.S. Provisional Patent Application No. 62 / 624,109, entitled "WAVEGUIDE ILLUMINATOR", filed on January 30, 2018, under 35 U.S.C.§119(e). The entire disclosure of each of the above applications is hereby incorporated by reference herein.

[0004] Incorporation by reference

[0005] This application incorporates by reference the entire contents of each of the following patent applications: the U.S. application Ser. No. 14 / 555,585, filed on November 27, 2014, which is published as U.S. Publication No. 2015 / 0205126 on July 23, 2015; the U.S. application Ser. No. 14 / 690,401, filed on April 18, 2015, which is published as U.S. Publication No. 2015 / 0302652 on October 22, 2015; the U.S. application Ser. No. 14 / 212,961, filed on March 14, 2014, which is now U.S. Patent No. 9,417,452, published on August 16, 2016; the U.S. application Ser. No. 14 / 331,218, filed on July 14, 2014, which is published as U.S. Publication No. 2015 / 0309263 on October 29, 2015; and the U.S. Provisional Application No. 62 / 597,359, filed on December 11, 2017. Technical field

[0006] The present disclosure relates to a display system having a common optical device for both spatial light modulator illumination and image projection. Background art

[0007] Modern computing and display technologies have facilitated the development of systems for so-called "virtual reality" or "augmented reality" experiences, in which digitally reproduced images or portions thereof are presented to a user in a manner that appears or can be perceived as real. Virtual reality or "VR" scenarios typically involve the presentation of digital or virtual image information and are opaque to other actual real-world visual inputs; augmented reality or "AR" scenarios typically involve the presentation of digital or virtual image information as an augmentation of the visualization of the actual world around the user. Mixed reality or "MR" scenarios are AR-type scenarios and typically involve virtual objects that are integrated into and responsive to the natural world. For example, an MR scenario can include AR image content that appears to be occluded by objects in the real world or otherwise perceived as interacting with objects in the real world.

[0008] Reference Figure 1 , depicts an augmented reality scenario 10. A user of AR technology sees a real-world park-like setting 20, which features people, trees, buildings in the background, and a concrete platform 30. The user also perceives that he / she "sees" "virtual content", such as a robotic statue 40 standing on the real-world platform 30, and a flying cartoon avatar character 50 that appears to be an avatar of a bumblebee. These elements 50, 40 are "virtual" because they do not exist in the real world. Since the human visual perception system is complex, it is extremely challenging to develop AR technology that produces virtual image elements that contribute to a comfortable, natural-feeling, and rich presentation among other virtual or real-world image elements.

[0009] The systems and methods disclosed herein address various challenges associated with AR and VR technologies.

[0010] A polarization beam splitter can be used in a display system to direct polarized light to a light modulator and then to a viewer. Generally, there has been a continuing requirement to reduce the size of display systems, and thus there is also a need to reduce the size of the components that make up the display system, including components that utilize a polarization beam splitter. SUMMARY OF THE INVENTION

[0011] The systems, methods, and devices of the present disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0012] Details of one or more embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. It is noted that the relative dimensions of the following figures may not be drawn to scale.

[0013] This document describes various examples of a head-mounted display system having a common optical device for both spatial light modulator illumination and image projection.

[0014] Example:

[0015] 1. A head-mounted display system configured to project light to a user's eyes to display augmented reality image content in the user's field of view, the head-mounted display system comprising:

[0016] A frame configured to be supported on the user's head;

[0017] At least one light source configured to output light;

[0018] A spatial light modulator arranged to receive light from the at least one light source;

[0019] An eyepiece disposed on the frame, the eyepiece configured to direct light from the spatial light modulator into the user's eyes to display augmented display image content in the user's field of view, at least a portion of the eyepiece being transparent and disposed at a position in front of the user's eyes when the user wears the head-mounted display, wherein the transparent portion transmits light from a portion of the physical environment in front of the user to the user's eyes to provide a view of the portion of the physical environment in front of the user, the eyepiece comprising:

[0020] (a) At least one waveguide;

[0021] (b) At least one coupling-in optical element configured to couple light from the spatial light modulator into the at least one waveguide; and

[0022] (c) At least one coupling-out optical element configured to couple out light guided within the waveguide and direct the light to the user's eyes; and

[0023] An optical device having a focal power, the optical device arranged to receive light output from the light source, the optical device being arranged relative to the spatial light modulator such that the light received from the light source propagates through the optical device and illuminates the spatial light modulator,

[0024] wherein the head-mounted display system is configured such that the light illuminating the spatial light modulator is redirected back through the optical device and coupled into the at least one waveguide through the at least one coupling-in optical element, and at least a portion of the coupled light is emitted from the at least one waveguide through the at least one coupling-out optical element and directed to the user's eyes.

[0025] 2. The head-mounted display system according to Example 1, wherein the at least one light source includes a multi-color light source configured to emit different colored lights at different times.

[0026] 3. The head-mounted display system according to any one of the above examples, wherein the at least one light source includes a red, green, and blue (RGB) light source configured to emit red, green, and blue lights at different times.

[0027] 4. The head-mounted display system according to any one of the above examples, wherein the at least one light source includes a cyan, magenta, and yellow (CMY) light source configured to emit cyan, magenta, and yellow lights at different times.

[0028] 5. The head-mounted display system according to any one of the above examples, comprising:

[0029] a plurality of laterally displaced light emitters configured to output light;

[0030] condensing optics configured to collect light from the plurality of light emitters;

[0031] a diffuser; and

[0032] a plurality of holes adjacent to the diffuser.

[0033] 6. The head-mounted display system according to any one of the above examples, further comprising coupling optics disposed relative to the light emitter to collect light output from the light source.

[0034] 7. The head-mounted display system according to Example 6, wherein the coupling optics includes a compound parabolic concentrator (CPC).

[0035] 8. The head-mounted display system according to any one of the above examples, wherein the spatial light modulator includes a reflective spatial light modulator.

[0036] 9. The head-mounted display system according to any one of the above examples, wherein the spatial light modulator includes a liquid crystal spatial light modulator.

[0037] 10. The head-mounted display system according to any one of the above examples, wherein the spatial light modulator includes a vertically aligned liquid crystal spatial light modulator.

[0038] 11. The head-mounted display system according to any one of the above examples, wherein the spatial light modulator includes a deflection-based spatial light modulator.

[0039] 12. The head-mounted display system according to any one of the above examples, wherein the spatial light modulator includes a movable mirror array.

[0040] 13. The head-mounted display system according to any of the above examples further includes a light absorber such that, in the closed state, light is guided by the movable mirror array to the light absorber, and in the open state, light is guided to the corresponding light-coupling optical element.

[0041] 14. The head-mounted display system according to any of the above examples, wherein the at least one waveguide includes a material transparent to visible light, the material having a refractive index sufficient to guide light in the waveguide by total internal reflection.

[0042] 15. The head-mounted display system according to any of the above examples, wherein the at least one waveguide includes a waveguide stack.

[0043] 16. The head-mounted display system according to example 15, wherein different waveguides in the waveguide stack are configured to output light having different respective colors.

[0044] 17. The head-mounted display system according to example 15 or 16, wherein a first waveguide, a second waveguide, and a third waveguide in the waveguide stack are configured to output first-color light, second-color light, and third-color light respectively, and the first-color light, the second-color light, and the third-color light are red light, blue light, and green light respectively.

[0045] 18. The head-mounted display system according to any one of examples 15 to 16, wherein different waveguides in the waveguide stack are configured to output light having different wavefronts, and the light having different wavefronts has at least one of different amounts of divergence, convergence, and collimation, as if projected from different distances from the user's eyes.

[0046] 19. The head-mounted display system according to any of the above examples, wherein the at least one waveguide is configured to couple in light of a specific polarization.

[0047] 20. The head-mounted display system according to any of the above examples, wherein the light-coupling optical element includes at least one of a diffractive optical element and a reflector.

[0048] 21. The head-mounted display system according to any of the above examples, wherein the at least one light-coupling optical element includes a plurality of color-selective light-coupling optical elements configured to couple in different respective colors.

[0049] 22. The head-mounted display system according to Example 21, wherein the plurality of light-coupling optical elements include a first light-coupling optical element and a second light-coupling optical element, and the second light-coupling optical element is disposed above the first light-coupling optical element, such that light of a first color can be coupled into a first waveguide by the first light-coupling optical element and guided therein, and light of a second color different from the first color can propagate through the first light-coupling optical element to reach the second light-coupling optical element, and can be coupled into a second waveguide by the second light-coupling optical element and guided therein.

[0050] 23. The head-mounted display system according to Example 22, wherein the plurality of light-coupling optical elements include a third light-coupling optical element, which is disposed above the first light-coupling optical element and the second light-coupling optical element, such that light of a third color different from the first color and the second color can propagate through the first light-coupling optical element and the second light-coupling optical element to reach the third light-coupling optical element, and can be coupled into a third waveguide and guided therein.

[0051] 24. The head-mounted display system according to Example 23, wherein the first color includes one of red, green, and blue, wherein the second color includes one of red, green, and blue different from the first color, and wherein the third color includes one of red, green, or blue different from the first color and the second color.

[0052] 25. The head-mounted display system according to any one of the above examples, wherein the at least one light-coupling optical element includes a light-coupling optical element configured to couple light of multiple colors into one of the at least one waveguides to guide the light therein.

[0053] 26. The head-mounted display system according to any one of the above examples, wherein the at least one light source includes a light source disposed relative to the optical device and the spatial light modulator to direct light to the light-coupling optical element configured to couple light of multiple colors into one of the at least one waveguides, and the light source is configured to emit light of different colors at different times.

[0054] 27. The head-mounted display system according to any one of the above examples, wherein the at least one light-coupling optical element includes a light-coupling optical element configured to couple red light, green light, and blue light into one of the at least one waveguides to guide the light therein.

[0055] 28. The head-mounted display system according to any one of the above examples, wherein the at least one light-coupling optical element is configured to couple light of a predetermined polarization.

[0056] 29. The head-mounted display system according to any of the above examples, wherein the at least one coupling-in optical element includes a plurality of coupling-in optical elements that are laterally displaced relative to each other.

[0057] 30. The head-mounted display system according to Example 29, wherein the plurality of coupling-in optical elements includes a first coupling-in optical element configured to couple light of multiple colors into a first waveguide of the at least one waveguide to guide the light therein, and a second coupling-in optical element configured to couple light of multiple colors into a second waveguide of the at least one waveguide to guide the light therein, and the first coupling-in optical element and the second coupling-in optical element are laterally displaced relative to each other.

[0058] 31. The head-mounted display system according to Example 29 or 30, wherein the at least one light source includes a first light source arranged relative to the optical device and the spatial light modulator to direct light to the first coupling-in optical element and a second light source arranged relative to the optical device and the spatial light modulator to direct light to the second coupling-in optical element.

[0059] 32. The head-mounted display system according to Example 30, wherein the at least one light source includes a first light source arranged relative to the optical device and the spatial light modulator to direct light to the first coupling-in optical element, and the first light source is configured to emit different colors of light at different times.

[0060] 33. The head-mounted display system according to Example 32, wherein the at least one light source includes a second light source arranged relative to the optical device and the spatial light modulator to direct light to the second coupling-in optical element, and the second light source is configured to emit different colors of light at different times.

[0061] 34. The head-mounted display system according to Example 33, wherein the eyepiece is configured such that the light coupled out from the first waveguide and the light coupled out from the second waveguide have at least one of different amounts of convergence, divergence, and collimation, and thus appear to originate from different depth planes.

[0062] 35. The head-mounted display system according to any one of Examples 31 to 34, wherein the eyepiece is configured such that the light coupled out from the first waveguide is collimated and the light output from the second waveguide diverges.

[0063] 36. The head-mounted display system according to any one of Examples 31 to 34, wherein the eyepiece is configured such that the light coupled out from the first waveguide diverges by a first amount and the light coupled out from the second waveguide diverges by a second amount, and the second amount is different from the first amount.

[0064] 37. The head-mounted display system according to any of the above examples, wherein the at least one coupling optical element includes a coupling optical element configured to couple red light, green light, and blue light into a waveguide to guide the light therein.

[0065] 38. The head-mounted display system according to any of the above examples, wherein the at least one light source includes a light source arranged relative to the optical device and the spatial light modulator to direct light to the at least one coupling optical element, the at least one coupling optical element being configured to couple red light, green light, and blue light into one of the at least one waveguides, and the at least one light source being configured to emit different red light, green light, and blue light at different times.

[0066] 39. The head-mounted display system according to example 31, wherein the first light source is a first color light source and the second light source is a second color light source having a color different from the first color.

[0067] 40. The head-mounted display system according to example 39, wherein the first light source is a red light source and the second color light source is one of a green light source and a blue light source.

[0068] 41. The head-mounted display system according to any of the above examples, wherein the at least one coupling optical element includes a plurality of groups of coupling optical elements, each group including a plurality of color-selective coupling optical elements configured to couple different respective colors, and each of the plurality of groups is laterally shifted relative to each other.

[0069] 42. The head-mounted display system according to example 41, wherein the plurality of coupling optical elements includes a first coupling optical element and a second coupling optical element, the second coupling optical element being disposed above the first coupling optical element such that light of a first color can be coupled by the first coupling optical element into a first waveguide to be guided therein, and light of a second color different from the first color can propagate through the first coupling optical element to the second coupling optical element and can be coupled by the second coupling optical element into a second waveguide to be guided therein.

[0070] 43. The system according to example 42, wherein the plurality of coupling optical elements includes a third coupling optical element disposed above the second coupling optical element such that a third color different from the first color and the second color can propagate through the first coupling optical element and the second coupling optical element to the third coupling optical element and can be coupled into a third waveguide to be guided therein.

[0071] 44. The head-mounted display system according to Example 43, wherein the first color includes one of red, green, and blue, wherein the second color includes one of red, green, and blue different from the first color, and wherein the third color includes one of red, green, or blue different from the first color and the second color.

[0072] 45. The head-mounted display system according to any one of the above examples, wherein the at least one coupling-in optical element includes a first group of coupling-in optical elements and a second group of coupling-in optical elements, the first group of coupling-in optical elements includes a plurality of color-selective coupling-in optical elements configured to couple in different respective colors, the second group of coupling-in optical elements includes a plurality of color-selective coupling-in optical elements configured to couple in different respective colors, and the first group and the second group are laterally displaced relative to each other.

[0073] 46. The head-mounted display system according to Example 45, wherein the first plurality of coupling-in optical elements includes a first coupling-in optical element and a second coupling-in optical element, the second coupling-in optical element is disposed above the first coupling-in optical element such that light of a first color can be coupled into a first waveguide by the first coupling-in optical element and guided therein, and a second color different from the first color can propagate through the first coupling-in optical element to the second coupling-in optical element and can be coupled into a second waveguide by the second coupling-in optical element and guided therein.

[0074] 47. The head-mounted display system according to Example 46, wherein the first plurality of coupling-in optical elements includes a third coupling-in optical element disposed above the first coupling-in optical element and the second coupling-in optical element such that a third color different from the first color and the second color can propagate through the first coupling-in optical element and the second coupling-in optical element to the third coupling-in optical element and can be coupled into a third waveguide and guided therein.

[0075] 48. The head-mounted display system according to Example 47, wherein the first color includes one of red, green, and blue, wherein the second color includes one of red, green, and blue different from the first color, and wherein the third color includes one of red, green, or blue different from the first color and the second color.

[0076] 49. The head-mounted display system according to Example 48, wherein the second plurality of light-coupling optical elements includes a fourth light-coupling optical element and a fifth light-coupling optical element, and the fifth light-coupling optical element is disposed above the fourth light-coupling optical element such that light of a fourth color can be coupled into the fourth waveguide by the fourth light-coupling optical element and guided therein, and a fifth color different from the first color can propagate through the fourth light-coupling optical element to the fifth light-coupling optical element and can be coupled into the fifth waveguide by the second light-coupling optical element and guided therein.

[0077] 50. The head-mounted display system according to Example 49, wherein the second plurality of light-coupling optical elements includes a sixth light-coupling optical element, which is disposed above the fourth light-coupling optical element and the fifth light-coupling optical element such that a sixth color different from the first color and the second color can propagate through the fourth light-coupling optical element and the fifth light-coupling optical element to the sixth light-coupling optical element and can be coupled into the sixth waveguide and guided therein.

[0078] 51. The head-mounted display system according to Example 50, wherein the eyepiece is configured such that the light coupled out from the first waveguide, the second waveguide, and the third waveguide has at least one of a different amount of convergence, divergence, and collimation from the light coupled out from the fourth waveguide, the fifth waveguide, and the sixth waveguide, and thus appears to originate from a different depth from the light output from the fourth waveguide, the fifth waveguide, and the sixth waveguide.

[0079] 52. The head-mounted display system according to Example 51, wherein the eyepiece is configured such that the light coupled out from the first waveguide, the second waveguide, and the third waveguide is collimated, and the light output from the fourth waveguide, the fifth waveguide, and the sixth waveguide diverges.

[0080] 53. The head-mounted display system according to Example 52, wherein the eyepiece is configured such that the light coupled out from the first waveguide, the second waveguide, and the third waveguide diverges, and the light output from the fourth waveguide, the fifth waveguide, and the sixth waveguide diverges by different amounts.

[0081] 54. The head-mounted display system according to any one of Examples 45 to 53, wherein the at least one light source includes a first light source disposed relative to the optical device and the spatial light modulator to direct light to the first group of light-coupling optical elements, and the first light source is configured to emit light of different colors at different times.

[0082] 55. The head-mounted display system according to any one of Examples 45 to 54, wherein the at least one light source includes a second light source arranged relative to the optical device and the spatial light modulator to direct light to the second group of light-coupling optical elements, and the second light source is also configured to emit different colored light at different times.

[0083] 56. The head-mounted display system according to any one of the above examples, wherein the at least one light-extracting optical element includes a diffractive optical element.

[0084] 57. The head-mounted display system according to any one of the above examples, wherein the at least one light-extracting element is configured to increase the size of the eye movement range along at least one first axis.

[0085] 58. The head-mounted display system according to Example 57, further comprising an orthogonal pupil expander, the orthogonal pupil expander including at least one light redirecting element in or on the at least one waveguide, the at least one light redirecting element being configured to increase the size of the eye movement range along a second axis orthogonal to the at least one first axis.

[0086] 59. The head-mounted display system according to Example 58, wherein the at least one light redirecting element includes a diffractive optical element.

[0087] 60. The head-mounted display system according to any one of the above examples, wherein at least a portion of the at least one waveguide extends between the at least one light source and the optical device, and light from the at least one light source guided by the optical device propagates through the portion of the at least one waveguide to reach the optical device.

[0088] 61. The head-mounted display system according to any one of the above examples, wherein the at least one waveguide has a first side and a second side opposite the first side, and the optical device and the spatial light modulator are arranged on the first side such that light from the spatial light modulator is directed to the first side.

[0089] 62. The head-mounted display system according to Example 61, wherein the at least one light source is arranged on the first side such that light from the at least one light source is incident on the first side before propagating through the optical device to reach the spatial light modulator.

[0090] 63. The head-mounted display system according to Example 61, wherein the at least one light source is arranged on the second side such that light from the at least one light source is incident on the second side before propagating through the optical device to reach the spatial light modulator.

[0091] 64. The head-mounted display system according to Example 63, wherein the at least one waveguide is disposed between the at least one light source and the optical device.

[0092] 65. The head-mounted display system according to any of the above examples, further comprising a light source coupling optical element disposed relative to a portion of the at least one waveguide adjacent to the at least one light source so as to receive light from the at least one light source and couple the light from the at least one light source into the portion of the at least one waveguide to be guided therein.

[0093] 66. The system according to Example 65, further comprising an output coupling optical element relative to the portion of the at least one waveguide adjacent to the light source, which is configured to guide the light guided in the portion of the at least one waveguide out of the portion of the at least one waveguide, through the optical device and to the spatial light modulator.

[0094] 67. The head-mounted display system according to Example 66, wherein the head-mounted display system is configured such that at least a portion of the light coupled into the optical device from the portion of the at least one waveguide adjacent to the at least one light source is incident on the spatial light modulator, propagates through the optical device again, is incident on a second portion of the at least one waveguide, is guided therein again, is coupled out therefrom and is guided to the user's eyes.

[0095] 68. The head-mounted display system according to any one of Examples 65 to 67, further comprising an isolator to reduce crosstalk from the portion of the at least one waveguide adjacent to the light source to the second portion of the at least one waveguide.

[0096] 69. The head-mounted display system according to Example 68, wherein the isolator includes one of an opaque surface and a reflective surface.

[0097] 70. The system according to Example 58, wherein the isolator is disposed in the at least one waveguide.

[0098] 71. The head-mounted display system according to any one of Examples 65 to 70, wherein the at least one waveguide has a first side and a second side opposite to the first side, and the optical device and the spatial light modulator are disposed on the first side of the at least one waveguide.

[0099] 72. The head-mounted display system according to Example 71, wherein the at least one light source is disposed on the first side of the at least one waveguide such that light from the at least one light source is incident on the first side of the at least one waveguide to be guided therein, and the light guided in the portion of the at least one waveguide is coupled out from the first side of the at least one waveguide and reaches the optical device and the spatial light modulator located on the first side.

[0100] 73. The head-mounted display system according to Example 71, wherein the at least one light source is disposed on the second side of the at least one waveguide such that light from the at least one light source is incident on the second side of the at least one waveguide before propagating through the optical device to reach the spatial light modulator.

[0101] 74. The head-mounted display system according to Example 71 or 73, wherein the at least one waveguide is disposed between the at least one light source and the optical device.

[0102] 75. The head-mounted display system according to any of the above examples, further comprising at least one waveguide optically coupled to the at least one light source to receive light from the at least one light source, to guide the light from the at least one light source therein, and to couple the light guided therein into the optical device such that at least a portion of the light coupled into the optical device from the at least one waveguide is incident on the spatial light modulator, propagates through the optical device again and is incident on the at least one waveguide, is guided therein, is coupled out therefrom and is guided to the user's eyes.

[0103] 76. The head-mounted display system according to Example 75, further comprising a coupling-in element disposed on the at least one waveguide to receive light from the light source and couple the light from the light source into the at least one waveguide to be guided therein.

[0104] 77. The head-mounted display system according to Example 76, further comprising a coupling-out element disposed on the at least one waveguide to receive the light guided in the at least one waveguide from the light source, and couple the light guided in the at least one waveguide out of the at least one waveguide and through the optical device to reach the spatial light modulator.

[0105] 78. The head-mounted display system according to any one of Examples 75 to 77, further comprising an isolator to reduce crosstalk between the at least one waveguide and the at least one waveguide.

[0106] 79. The head-mounted display system according to Example 78, wherein the isolator includes at least one of an opaque surface and a reflective surface.

[0107] 80. The head-mounted display system according to Example 78 or 79, wherein the isolator is disposed in or on the at least one waveguide.

[0108] 81. The head-mounted display system according to any one of Examples 75 to 80, wherein the at least one waveguide has a first side surface and a second side surface opposite to the first side surface, and the optical device and the spatial light modulator are disposed on the first side surface of the at least one waveguide.

[0109] 82. The head-mounted display system according to Example 81, wherein the at least one light source is disposed on the first side surface of the at least one waveguide such that light from the at least one light source is incident on the first side surface of the at least one waveguide to be guided therein, and the light guided in the at least one waveguide is coupled out of the first side surface of the at least one waveguide to reach the optical device and the spatial light modulator on the first side surface.

[0110] 83. The head-mounted display system according to Example 81, wherein the at least one light source is disposed on the second side surface of the at least one waveguide such that light from the at least one light source is incident on the second side surface of the at least one waveguide to guide the light therein, and the light guided in the at least one optical waveguide is coupled out of the first side surface of the at least one waveguide to reach the optical device and the spatial light modulator on the first side surface.

[0111] 84. The head-mounted display system according to Example 81 or 83, wherein the at least one waveguide is disposed between the at least one light source and the optical device.

[0112] 85. The head-mounted display system according to any one of the above examples, wherein the optical device includes one or more lenses.

[0113] 86. The head-mounted display system according to any one of the above examples, wherein the optical device includes a plurality of lenses.

[0114] 87. The head-mounted display system according to any one of the above examples, wherein the optical device has a positive optical power.

[0115] 88. The head-mounted display system according to any one of the above examples, wherein the optical device includes one or more refractive optical elements.

[0116] 89. The head-mounted display system according to any one of the above examples, wherein the spatial light modulator is configured to modulate polarization.

[0117] 90. The head-mounted display system according to any one of the above examples, further comprising an analyzer located in the optical path between the spatial light modulator and the user's eyes.

[0118] 91. The head-mounted display system according to Example 90, wherein the analyzer is disposed in the optical path between the optical device and the at least one light-coupling optical element.

[0119] 92. The head-mounted display system according to any one of the above examples, further comprising a polarizer disposed between the at least one light source and the spatial light modulator.

[0120] 93. The head-mounted display system according to any one of the above examples, wherein the at least one light source includes a polarized light source.

[0121] 94. The head-mounted display system according to any one of the above examples, wherein the polarizer is disposed between the optical device and the spatial light modulator.

[0122] 95. The head-mounted display system according to Example 94, wherein the polarizer is directly disposed on the spatial light modulator.

[0123] 96. The head-mounted display system according to any one of the above examples, wherein the polarizer includes a wire grid polarizer.

[0124] 97. The head-mounted display system according to Example 90, wherein the analyzer is a circular polarizer.

[0125] 98. The head-mounted display system according to any one of the above examples, further comprising a variable optical element having an adjustable optical power.

[0126] 99. The head-mounted display system according to Example 98, wherein the variable optical element includes a lens or a mirror.

[0127] 100. The head-mounted display system according to Example 98 or 99, wherein the variable optical element is configured to have a first state and a second state, wherein in the first state, the variable optical element has a different optical power from that in the second state.

[0128] 101. The head-mounted display system according to Example 100, wherein the variable optical element has a negative optical power in the first state and a zero optical power in the second state.

[0129] 102. The head-mounted display system according to Example 100, wherein the variable optical element has a positive optical power in the first state and has zero optical power in the second state.

[0130] 103. The head-mounted display system according to Example 100, wherein the variable optical element has a first negative optical power in the first state and has a different second negative optical power in the second state.

[0131] 104. The head-mounted display system according to Example 100, wherein the variable optical element has a first positive optical power in the first state and has a different second positive optical power in the second state.

[0132] 105. The head-mounted display system according to Example 100, wherein the variable optical element has a first negative optical power in the first state and has a second positive optical power in the second state.

[0133] 106. The head-mounted display system according to Example 98, wherein the variable optical element includes a liquid lens.

[0134] 107. The head-mounted display system according to any of the above examples, further comprising an adjustable dimming device, which includes an optical element that provides variable attenuation of the transmitted light.

[0135] 108. The head-mounted display system according to any of the above examples, further comprising a prescription lens, which is configured to provide refractive correction for the user's eyes.

[0136] 109. The head-mounted display system according to any of the above examples, further comprising a static lens, which is disposed in the path between the at least one waveguide and the user's eyes.

[0137] 110. The head-mounted display system according to Example 91, wherein the analyzer is configured to also function as a polarizer to enable light to propagate from the light source to the optical device.

[0138] 111. The head-mounted display system according to any of the above examples, further comprising a color filter array, which is disposed on the side of the waveguide adjacent to the user, wherein the color filter array includes a plurality of different color filters.

[0139] 112. The head-mounted display system according to Example 111, wherein the color filter array includes absorbing materials disposed between the color filters, which are configured to reduce the propagation and reflection of stray light.

[0140] 113. The head-mounted display system according to any of the above examples, wherein the polarizer can be disposed in the optical path of the light source and is configured to transmit light of a first polarization and reflect light of a second polarization, wherein a portion of the reflected light of the second polarization that is directed toward the light source acquires the first polarization.

[0141] 114. The head-mounted display system according to Example 113, wherein a portion of the reflected light of the second polarization that is directed toward the light source acquires the first polarization by being reflected from a coupling optical device configured to collect light from the light source.

[0142] 115. The head-mounted display system according to any of the above examples, further comprising a quarter-wave plate.

[0143] 116. The head-mounted display system according to any of the above examples, further comprising a compensator configured to provide a more consistent orthogonal rotation of the light.

[0144] 117. The head-mounted display system according to any of the above examples, wherein the optical device and the spatial light modulator are inclined with respect to each other.

[0145] 118. The head-mounted display system according to any of the above examples, wherein the coupling optical device, the optical device, and the spatial light modulator are inclined with respect to the eyepiece.

[0146] 119. The head-mounted display system according to any of the above examples, wherein the coupling optical device, the optical device, and the spatial light modulator are inclined with respect to the eyepiece.

[0147] 120. The head-mounted display system according to any of the above examples, wherein the light from the light source is configured to be recycled or reused.

[0148] 121. The head-mounted display system according to any of the above examples, further comprising a polarizer configured to transmit light of a first polarization from the light source to the optical device and reflect light of a different second polarization back to the light source.

[0149] 122. The head-mounted display system according to any of the above examples, further comprising a coupling element between the light source and the polarizer that converts at least some of the light of the second polarization reflected by the polarizer into light of the first polarization.

[0150] 123. The head-mounted display system according to any of the above examples, wherein the light source includes a plurality of laterally displaced light emitters configured to output light.

[0151] 124. The head-mounted display system according to any one of the above examples further includes a condenser optical device or a coupling element configured to collect light from the plurality of light emitters.

[0152] 125. The head-mounted display system according to any one of the above examples further includes a diffuser in the optical path between the light source and the optical device.

[0153] 126. The head-mounted display system according to any one of the above examples further includes one or more holes between the light source and the optical device.

[0154] 127. The head-mounted display system according to any one of the above examples further includes a plurality of holes between the light source and the optical device.

[0155] 128. The head-mounted display system according to any one of the above examples further includes a diffuser and a plurality of holes between the light source and the optical device, the diffuser being adjacent to the holes.

[0156] 129. The head-mounted display system according to any one of the above examples, wherein the light source includes one or more laser diodes.

[0157] 130. The head-mounted display system according to any one of the above examples further includes a coupling optical device disposed relative to the light source to collect light output from the light source.

[0158] 131. The head-mounted display system according to Example 130, wherein the coupling optical device includes a compound parabolic concentrator (CPC).

[0159] 132. The head-mounted display system according to any one of the above examples further includes a condenser optical device disposed relative to the light source to collect light output from the light source.

[0160] 133. The head-mounted display system according to any one of the above examples, wherein the condenser optical device includes one or more lenses.

[0161] 134. The head-mounted display system according to any one of the above examples, wherein the condenser optical device includes a plurality of lenses.

[0162] 135. The head-mounted display system according to any one of the above examples further includes a quarter-wave retarder between the light source and the optical device.

[0163] 136. The head-mounted display system according to any one of the above examples, wherein a polarizer is attached to the spatial light modulator.

[0164] 137. The head-mounted display system according to any one of the above examples, wherein the polarizer is adhered to the spatial light modulator by an adhesive.

[0165] 138. The head-mounted display system according to any one of the above examples, wherein the polarizer is attached to the spatial light modulator using a mechanical fixing device.

[0166] 139. The head-mounted display system according to any one of the above examples, wherein a compensator is attached to the spatial light modulator.

[0167] 140. The head-mounted display system according to any one of the above examples, wherein the compensator is adhered to the spatial light modulator by an adhesive.

[0168] 141. The head-mounted display system according to any one of the above examples, wherein the compensator is adhered to the spatial light modulator using a mechanical fixing device.

[0169] 142. The head-mounted display system according to any one of the above examples, wherein a retarder is attached to the spatial light modulator.

[0170] 143. The head-mounted display system according to any one of the above examples, wherein the retarder is adhered to the spatial light modulator by an adhesive.

[0171] 144. The head-mounted display system according to any one of the above examples, wherein the retarder is adhered to the spatial light modulator using a mechanical fixing device.

[0172] 145. The head-mounted display system according to any one of the above examples, wherein a quarter-wave retarder is attached to the spatial light modulator.

[0173] 146. The head-mounted display system according to any one of the above examples, wherein the quarter-wave retarder is adhered to the spatial light modulator by an adhesive.

[0174] 147. The head-mounted display system according to any one of the above examples, wherein the quarter-wave retarder is adhered to the spatial light modulator using a mechanical fixing device.

[0175] 148. The head-mounted display system according to any one of the above examples, wherein the polarizer includes a wire-grid polarizer.

[0176] 149. The head-mounted display system according to any one of the above examples, further comprising a circular polarizer between the spatial light modulator and the light-coupling optical element.

[0177] 150. The head-mounted display system according to Example 149, wherein the circular polarizer includes a linear polarizer and a quarter-wave retarder.

[0178] 151. The head-mounted display system according to any one of the above examples, further comprising a single polarizer between the optical device and the at least one waveguide and between the light source and the optical device.

[0179] 152. The head-mounted display system according to any one of the above examples, wherein the light absorber includes an absorbing material.

[0180] 153. The head-mounted display system according to any one of the above examples, wherein the light absorber includes an absorbing material surrounding the color filters in the color filter array.

[0181] 154. The head-mounted display system according to any one of the above examples, wherein the light source is laterally disposed relative to the at least one waveguide such that light from the light source is directed into the optical element without propagating through the at least one waveguide.

[0182] 155. The head-mounted display system according to any one of the above examples, wherein the light source is disposed on a transparent layer that extends laterally relative to the at least one waveguide such that light from the light source is directed into the optical device without propagating through the at least one waveguide.

[0183] 156. The head-mounted display system according to any one of the above examples, wherein the light source is disposed on a transparent layer that is closer to the side of the at least one waveguide closer to the environment in front of the user than to the side of the at least one waveguide closer to the user's eyes, the transparent layer extending laterally relative to the at least one waveguide such that light from the light source is directed into the optical device without propagating through the at least one waveguide.

[0184] 157. The head-mounted display system according to any one of the above examples, wherein the light source is disposed on a transparent layer that is closer to the side of the at least one waveguide closer to the user's eyes than to the side of the at least one waveguide closer to the environment in front of the user, the transparent layer extending laterally relative to the at least one waveguide such that light from the light source is directed into the optical device without propagating through the at least one waveguide.

[0185] 158. The head-mounted display system according to any one of the above examples, wherein the transparent layer includes a cover glass.

[0186] 159. The head-mounted display system according to any one of the above examples further includes a plurality of color filters that are laterally displaced relative to each other, the color filters being laterally aligned with respect to a plurality of light-coupling optical elements that are laterally displaced relative to each other such that light propagating through a corresponding color filter is incident on a corresponding light-coupling optical element.

[0187] 160. The head-mounted display system according to any one of the above examples, wherein the plurality of color filters includes a color filter array.

[0188] 161. The head-mounted display system according to any one of the above examples further includes a polarizer that is disposed in an optical path between the spatial light modulator and the optical device.

[0189] 162. The head-mounted display system according to any one of the above examples further includes an analyzer that is disposed in an optical path between the spatial light modulator and the optical device.

[0190] 163. The head-mounted display system according to any one of the above examples further includes a compensator that is disposed in an optical path between the spatial light modulator and the optical device.

[0191] 164. The head-mounted display system according to any one of the above examples further includes a retarder that is disposed in an optical path between the spatial light modulator and the optical device.

[0192] 165. The head-mounted display system according to any one of the above examples further includes a quarter-wave retarder that is disposed in an optical path between the spatial light modulator and the optical device.

[0193] 166. The head-mounted display system according to any one of the above examples further includes a first circular polarizer that is located between the at least one waveguide and the optical device having a focal power.

[0194] 167. The head-mounted display system according to Example 166, wherein the first circular polarizer is located between the light source and the optical device having a focal power.

[0195] 168. The head-mounted display system according to any one of the above examples further includes a second circular polarizer that is located between the optical device having a focal power and the spatial light modulator.

[0196] 169. The head-mounted display system according to Example 168 further includes a retarder that is located between the second circular polarizer and the spatial light modulator.

[0197] 170. The head-mounted display system according to Example 168 or 169 further includes a third circular polarizer located between the second circular polarizer and the spatial light modulator.

[0198] 171. The head-mounted display system according to Example 170 further includes a retarder located between the second circular polarizer and the third circular polarizer.

[0199] 172. The head-mounted display system according to any of the above examples further includes a compensator located between the optical device having a focal power and the spatial light modulator.

[0200] 173. The head-mounted display system according to any one of Examples 168 to 171 further includes a compensator located between the second circular polarizer and the spatial light modulator.

[0201] 174. The head-mounted display system according to any one of Examples 170 to 171 further includes a compensator located between the third circular polarizer and the spatial light modulator.

[0202] 175. The head-mounted display system according to any of the above examples further includes a cover glass located between the optical device having a focal power and the spatial light modulator.

[0203] 176. The head-mounted display system according to any one of Examples 168 to 174 further includes a cover glass located between the second circular polarizer and the spatial light modulator.

[0204] 177. The head-mounted display system according to any one of Examples 170 to 174 further includes a cover glass located between the third circular polarizer and the spatial light modulator.

[0205] 178. The head-mounted display system according to any one of Examples 172 to 174 further includes a cover glass located between the compensator and the spatial light modulator.

[0206] 179. The head-mounted display system according to any of the above examples further includes at least one optical surface that is tilted with respect to the at least one waveguide to redirect light reflected from the optical surface.

[0207] 180. The head-mounted display system according to any of the above examples further includes at least one optical surface that is tilted with respect to the spatial light modulator to redirect light reflected from the optical surface.

[0208] 181. The head-mounted display system according to any one of the above examples further includes at least one optical surface that is tilted relative to at least one polarizer or retarder to redirect light reflected from the optical surface.

[0209] 182. The head-mounted display system according to any one of the above examples further includes at least one optical surface whose normal is tilted relative to the optical axis of the optical device having a focal power to redirect light reflected from the optical surface.

[0210] 183. The head-mounted display system according to any one of Examples 179 to 182, wherein the at least one tilted optical surface redirects the reflected light away from the coupling optical element of the at least one waveguide.

[0211] 184. The head-mounted display system according to any one of Examples 179 to 183, wherein the at least one tilted optical surface redirects the reflected light such that a small amount of the reflected light is coupled into the at least one waveguide and guided therein.

[0212] 185. The head-mounted display system according to any one of Examples 179 to 184, wherein the at least one tilted optical surface redirects the reflected light such that a small amount of the reflected light is directed to the user's eyes.

[0213] 186. The head-mounted display system according to any one of Examples 179 to 185, wherein the at least one tilted optical surface redirects at least some of the reflected light to the light source.

[0214] 187. The head-mounted display system according to any one of Examples 179 to 186 further includes a light absorber to receive at least some of the reflected light from the at least one tilted optical surface.

[0215] 188. The head-mounted display system according to any one of Examples 179 to 187, wherein the at least one tilted optical surface is on the cover glass. [[ID=z2]]

[0216] 189. The head-mounted display system according to any one of Examples 179 to 188, wherein the at least one tilted optical surface is on one or more of the following: at least one retarder, at least one polarizer, or at least one compensator.

[0217] 190. The head-mounted display system according to any one of the above examples, wherein the cover glass is wedge-shaped.

[0218] 191. The head-mounted display system according to any one of the above examples, wherein at least one retarder, at least one polarizer, or at least one compensator is wedge-shaped.

[0219] 192. The head-mounted display system according to any one of the above examples, further comprising a polarization rotator disposed relative to the light source to rotate the polarization of light emitted therefrom.

[0220] 193. The head-mounted display system according to Example 166 or 167, further comprising a polarization rotator disposed between the light source and the first circular polarizer.

[0221] 194. The head-mounted display system according to any one of the above examples, wherein the at least one light-coupling optical element includes a first light-coupling optical element and a second light-coupling optical element, and the head-mounted display system further comprises a first color filter and a second color filter respectively associated with the first light-coupling optical element and the second light-coupling optical element.

[0222] 195. The head-mounted display system according to Example 194, wherein the first color filter transmits more light of a first color than the second color filter, and the second color filter transmits more light of the second color than the first color filter.

[0223] 196. The head-mounted display system according to Example 194 or 195, wherein the at least one waveguide includes a first waveguide and a second waveguide, wherein the first light-coupling optical element couples more light of the first color into the first waveguide than the second color filter, and the second light-coupling optical element couples more light of the second color than the first color into the second waveguide.

[0224] 197. The head-mounted display system according to any one of Examples 194 to 196, wherein the first color filter and the second color filter are laterally aligned with the corresponding first light-coupling optical element and second light-coupling optical element.

[0225] 198. The head-mounted display system according to any one of Examples 194 to 197, further comprising a first light source and a second light source, wherein the first light source and the second light source are arranged to guide light through the first color filter and the second color filter respectively to reach the first light-coupling optical element and the second light-coupling optical element respectively.

[0226] 199. The head-mounted display system according to any one of Examples 194 to 197 further includes a first light source and a second light source, wherein the first color filter is disposed in a first optical path between the first light source and the first light-coupling optical element, and the second color filter is disposed in a second optical path between the second light source and the second light-coupling optical element.

[0227] 200. The head-mounted display system according to Example 198 or 199, wherein the first light source includes a first color light source configured to emit a first color, and the second light source includes a second color light source configured to emit a second color.

[0228] 201. The head-mounted display system according to Example 198 or 199, wherein the first light source and the second light source include a broadband color light source configured to emit both the first color and the second color. Description of the Drawings

[0229] Figure 1 Shows a view of augmented reality (AR) as seen by a user through an AR device.

[0230] Figure 2 Shows a conventional display system for simulating three-dimensional images for a user.

[0231] Figures 3A to 3C Shows the relationship between the radius of curvature and the focal radius.

[0232] Figure 4A Shows a representation of the accommodation-convergence response of the human visual system.

[0233] Figure 4B Shows examples of different accommodation states and convergence states of a user's pair of eyes.

[0234] Figure 4C Shows an example of a representation of a top view of the content viewed by a user via a display system.

[0235] Figure 4D Shows another example of a representation of a top view of the content viewed by a user via a display system.

[0236] Figure 5 Shows aspects of a method for simulating three-dimensional images by modifying wavefront divergence.

[0237] Figure 6 Shows an example of a waveguide stack for outputting image information to a user.

[0238] Figure 7 Shows an example of an output light beam output from a waveguide.

[0239] Figure 8 An example of a stacked waveguide assembly is shown, where each depth plane includes an image formed using a plurality of different component colors.

[0240] Figure 9A A cross-sectional side view of an example of a stacked waveguide group each including an optically coupled-in element is shown.

[0241] Figure 9B An example of Figure 9A one or more stacked waveguides is shown in a perspective view.

[0242] Figure 9C An example of Figure 9A and Figure 9B one or more stacked waveguides is shown in a top plan view.

[0243] Figure 9D An example of a wearable display system is shown.

[0244] Figure 10 is a side view of a projector assembly including a polarization beam splitter, where a light source injects light into one side of the beam splitter, and projection optics receives light from the other side of the beam splitter.

[0245] Figure 11A is a side view of an augmented reality display system that includes a light source, a spatial light modulator, optics for illuminating the spatial light modulator and projecting an image of the spatial light modulator (SLM), and a display for outputting image information to a user. The system includes an optically coupled-in element for coupling light from the optics into a waveguide, and an optically coupled-out element for coupling light out of the waveguide to the eye.

[0246] Figure 11B is Figure 11A a top view of the augmented reality display system shown above, which shows a waveguide having an optically coupled-in element, an optically coupled-out element, and a light source disposed thereon. The top view also shows an orthogonal pupil expander. <0>

[0247] Figure 11C is Figure 11A a side view of an augmented reality display system having a shared polarizer / analyzer and a polarization-based spatial light modulator (such as a liquid crystal on silicon SLM).

[0248] Figure 12A is a side view of an augmented reality display system that includes a multi-color light source (such as a time-division multiplexed RGB LED or a laser diode), a spatial light modulator, optics for illuminating the spatial light modulator and projecting an image of the spatial light modulator to the eye, and a waveguide stack, where different waveguides include different color-selective optically coupled-in elements and optically coupled-out elements.

[0249] Figure 12B is Figure 12A a side view of an augmented reality display system that further includes a MEMS (microelectromechanical)-based SLM, such as a movable mirror array (e.g., digital light processing (DLP TM ) technology) and a light absorber.

[0250] Figure 12C is Figure 12B a top view of a part of an augmented reality display system, schematically showing a lateral arrangement of an optically coupled-in element and a light absorber and one of the light sources.

[0251] Figure 13A is a perspective view of an augmented reality display system including a waveguide stack, where different waveguides include different optically coupled-in elements, and the optically coupled-in elements are laterally displaced relative to each other. One or more light sources that are also laterally displaced relative to each other are arranged to direct light to the corresponding optically coupled-in elements by passing the light through an optical device, reflecting the light from a spatial light modulator, and passing the reflected light through the optical device again.

[0252] Figure 13B is Figure 13A a side view of the example shown, showing the laterally displaced optically coupled-in element and light source and the optical device and spatial light modulator.

[0253] Figure 13C is Figure 13A and Figure 13B a top view of the augmented reality display system shown, showing one or more laterally displaced optically coupled-in elements and the associated one or more laterally displaced light sources.

[0254] Figure 14A is a side view of an augmented reality display system including a waveguide stack, where different waveguides include different optically coupled-in elements, and the optically coupled-in elements are laterally displaced relative to each other (in this example, the lateral displacement occurs in the z direction).

[0255] Figure 14B is Figure 14A a top view of the display system shown, showing the laterally displaced optically coupled-in element and light source.

[0256] Figure 14C is Figure 14A and Figure 14B an orthographic side view of the display system shown.

[0257] Figure 15 is a top view of an augmented reality display system that includes a group of waveguide stacks, where different waveguides include different optically coupled-in elements. The light sources and optically coupled-in elements are arranged differently from Figures 14A to 14CThe alternative configurations shown are arranged.

[0258] Figure 16A is a side view of an augmented reality display system that includes a plurality of sets of optically coupled-in elements that are laterally displaced relative to each other, each set including one or more color-selective optically coupled-in elements.

[0259] Figure 16B is Figure 16A a top view of the display system in

[0260] Figure 17 is a side view of an augmented reality display system that includes waveguides separated by a reflective surface that can couple out light guided in a portion of the waveguide adjacent a light source from that portion of the waveguide and couple it into an optical device toward a spatial light modulator. In this example, the optical device and the light source are shown as being disposed on the same side of the waveguide.

[0261] Figure 18 is a side view of an augmented reality display system that includes a waveguide for receiving light from a light source and guiding the light guided in the waveguide into an optical device and toward a spatial light modulator. The display system additionally includes a waveguide that receives light from the spatial light modulator and propagates the light back through the optical device. The waveguide includes a reflective surface for coupling out light. The waveguide further includes a reflective surface for coupling light into it. In this example, the optical device and the light source are shown as being disposed on the same side of the waveguide.

[0262] Figure 19 is a side view of an augmented reality display system that includes adaptive optical elements or variable-focus optical elements. A first variable optical element between the waveguide stack and the eye can change the divergence and collimation of light coupled out of the waveguide and directed to the eye to change the depth at which an object appears to be located. A second variable optical element on the opposite side of the waveguide stack can compensate for the effect of the first optical element on light from the augmented reality display system and the user's front environment. The augmented reality display system further includes prescription lenses to provide ophthalmic correction, such as refractive correction, for users with myopia, hyperopia, astigmatism, etc.

[0263] Figure 20A is a side view of an augmented reality display system that includes a color filter array. One or more laterally displaced coupled-in optical elements are located on different waveguides, and laterally displaced color filters are aligned with the corresponding coupled-in optical elements.

[0264] Figure 20B shows an Figure 20A augmented reality display system having a polarizer between the optical device and the spatial light modulator.

[0265] Figure 20Cshows a similar to Figure 20A and Figure 20B shown augmented reality display system, but uses a deflection-based spatial light modulator, such as a spatial light modulator based on movable micromirrors.

[0266] Figure 20D is a top view of a part of an augmented reality display system such as Figure 20C shown, which schematically shows a laterally shifted light source and a corresponding laterally shifted light-coupling optical element above a color filter array.

[0267] Figure 20E shows how a deflection-based spatial light modulator guides light away from a corresponding light-coupling optical element and onto a mask of color filters in a color filter array of an augmented reality display system surrounding Figure 20D

[0268] Figure 20F is a side view of an augmented reality display system that includes a cover glass disposed on the user side of a waveguide stack and a light source disposed on the world side of the cover glass.

[0269] Figure 20G is a side view of an augmented reality display system that includes a cover glass disposed on the world side of a waveguide stack and a light source disposed on the world side of the cover glass.

[0270] Figure 21 is a side view of an augmented reality display system that includes a light source equipped with a light recycler configured to recycle light, such as light of one polarization.

[0271] Figure 22 is a side view of one or more light sources that propagate light through corresponding condenser optics and one or more apertures. The light can also be propagated through a diffuser positioned adjacent to the one or more apertures.

[0272] Figure 23A is a side view of a part of an augmented reality display system that includes a light source, an optical device having a focal power, a waveguide for receiving and outputting image information to a user's eye, wherein the system further includes one or more retarders and polarizers configured to reduce reflections from optical surfaces that can enter the waveguide as ghosts.

[0273] Figure 23B is a side view of a part of an augmented reality display system such as Figure 23A shown, which has additional retarders and polarizers configured to reduce reflections that can produce ghosts.

[0274] Figure 23C is a side view of a part of an augmented reality display system such as Figure 23A and​Figure 23B Side view of an augmented reality display system having a reduced retarder and a polarizer configured to reduce reflections that can cause ghosting.

[0275] Figure 24 Is a side view of an augmented reality display system that utilizes an inclined surface, such as an inclined surface on a cover glass, to direct reflections so that they cannot be directed into the user's eyes, thereby potentially reducing ghosting reflections.

[0276] Figure 25 Is Figure 24 An embodiment of the system in which the inclined surface on the cover glass is configured to direct reflections towards a light absorber that absorbs light. Detailed Description

[0277] Reference will now be made to the accompanying drawings, in which like reference numerals refer to like components throughout. Unless otherwise indicated, the drawings are schematic and need not be drawn to scale.

[0278] Figure 2 A conventional display system for simulating three-dimensional images for a user is shown. It should be understood that the user's eyes are spaced apart and that when viewing a real object in the viewing space, each eye has a slightly different view of the object and an image of the object may be formed at different locations on the retina of each eye. This is referred to as binocular disparity and can be used by the human visual system to provide a sense of depth. The conventional display system simulates binocular disparity by presenting two distinct images 190, 200 having slightly different views of the same virtual object, where each image is for one eye 210a, 210b and these images correspond to views of the virtual object that cause each eye to perceive the virtual object as a real object at the desired depth. These images provide binocular cues that the user's visual system can interpret to infer a sense of depth.

[0279] Continue to refer Figure 2, images 190, 200 are spaced apart from eyes 210a, 210b by a distance 230 along the z-axis. The z-axis is parallel to the viewer's visual axis when the eyes are fixated on an object at optical infinity directly in front of the viewer. Images 190, 200 are flat and are located at a fixed distance from eyes 210a, 210b. Based on slightly different views of a virtual object in the images presented to eyes 210a, 210b respectively, the eyes can naturally rotate so that the images of the object fall on corresponding points on the retina of each eye, thus maintaining single binocular vision. This rotation can cause the lines of sight of each eye 210a, 210b to converge on a point in the space where the virtual object is perceived to be located. Thus, providing three-dimensional imagery generally involves providing binocular cues that can manipulate the convergence of the user's eyes 210a, 210b, and the human visual system interprets these cues to provide a sense of depth.

[0280] However, generating a realistic and comfortable sense of depth is challenging. It should be understood that light from objects at different distances from the eyes has wavefronts with different amounts of divergence. Figures 3A to 3C The relationship between distance and light divergence is shown. The distances between the objects and eye 210 are represented by distances R1, R2, and R3 in decreasing order. As Figures 3A to 3C shown, as the distance to the object decreases, the light becomes more divergent. Conversely, as the distance increases, the light becomes more collimated. In other words, it can be considered that the light field generated by a point (object or part of an object) has a spherical wavefront curvature that is a function of the distance of that point from the user's eyes. As the distance between the object and eye 210 decreases, the curvature increases. Although only a single eye 210 is shown for clarity in Figures 3A to 3C and other figures in this document, the discussion regarding eye 210 applies to both eyes 210a and 210b of the viewer.

[0281] Continuing to refer to Figures 3A to 3C, light from an object being looked at by a viewer's eyes can have different degrees of wavefront divergence. Due to the different amounts of wavefront divergence, the light can be focused differently by the eye's lens, which in turn may require the lens to assume different shapes to form a focused image on the retina of the eye. In the case where a focused image is not formed on the retina, the resulting retinal blur serves as an accommodation cue that causes the shape of the eye's lens to change until a focused image is formed on the retina. For example, the accommodation cue can trigger the relaxation or contraction of the ciliary muscle that surrounds the eye's lens, thereby adjusting the force applied to the zonular ligaments that hold the lens, and thus causing the shape of the eye's lens to change until the retinal blur of the object being looked at is eliminated or minimized, thereby forming a focused image of the object being looked at on the retina (e.g., the fovea) of the eye. The process by which the shape of the eye's lens changes can be referred to as accommodation, and the shape of the eye's lens required to form a focused image of the object being looked at on the retina (e.g., the fovea) of the eye can be referred to as the accommodative state.

[0282] Now referring to Figure 4A , a representation of the accommodation-convergence response of the human visual system is shown. Eye movement to look at an object causes the eyes to receive light from the object, where the light forms an image on each retina of the eyes. The presence of retinal blur in the image formed on the retina can provide an accommodation cue, and the relative position of the image on the retina can provide a convergence cue. The accommodation cue causes accommodation to occur, resulting in the eye's lens assuming a specific accommodative state that forms a focused image of the object on the retina (e.g., the fovea) of the eye. On the other hand, the convergence cue causes a convergence movement (eye rotation) to occur such that the images formed on each retina of each eye are at corresponding retinal points that maintain single binocular vision. At these positions, the eyes can be considered to have assumed a specific convergence state. Continuing to refer to Figure 4A , accommodation can be understood as the process by which the eyes achieve a specific accommodative state, and convergence can be understood as the process by which the eyes achieve a specific convergence state. As Figure 4A shown, if the user looks at another object, the accommodation and convergence states of the eyes may change. For example, if the user looks at a new object at a different depth on the z-axis, the accommodative state may change.

[0283] Without being limited by theory, it can be considered that a viewer of an object may perceive the object as "three-dimensional" due to a combination of convergence and accommodation. As described above, the convergence movement of the two eyes relative to each other (i.e., the rotation of the eyes that causes the pupils to move closer to or farther from each other and the lines of sight of the eyes to converge to fixate on an object) is closely related to the accommodation of the lenses of the eyes. Under normal circumstances, according to the relationship known as the "accommodation-convergence reflex", changing the shape of the lens of the eye to change the focus from one object to another object at a different distance will automatically cause a matching change in the convergence to the same distance. Similarly, under normal circumstances, a change in convergence will trigger a matching change in the shape of the lens.

[0284] Now referring to Figure 4B , an example of different accommodation and convergence states of the eyes is shown. A pair of eyes 222a is fixated on an object at optical infinity, while a pair of eyes 222b is fixated on an object 221 that is less than optical infinity. It is noteworthy that the convergence states of each pair of eyes are different. A pair of eyes 222a looks straight ahead, while a pair of eyes 222 converges on the object 221. The accommodation states of the eyes forming each pair of eyes 222a and 222b are also different, as indicated by the different shapes of the lenses 220a, 220b.

[0285] However, many users of traditional "3-D" display systems find these traditional systems uncomfortable or simply unable to perceive a sense of depth because of the mismatch between the accommodation and convergence states in these displays. As described above, many stereoscopic or "3-D" display systems display a scene by providing slightly different images to each eye. Such systems are uncomfortable for many viewers because, among other factors, they can only provide different presentations of the scene and cause a change in the convergence state of the eyes without a corresponding change in the accommodation state. Instead, the images are presented by a display located at a fixed distance from the eyes so that the eyes view all the image information in a single accommodation state. This arrangement works by causing a change in the convergence state without a matching change in the accommodation state, which violates the "accommodation-convergence reflex". It can be considered that this mismatch causes discomfort to the viewer. A display system that provides a better match between accommodation and convergence can form a more realistic and comfortable three-dimensional image simulation.

[0286] Without being limited by theory, it can be considered that the human eye can generally interpret a limited number of depth planes to provide depth perception. Therefore, a highly believable simulation of perceived depth can be achieved by providing different presentations of images corresponding to each of these limited number of depth planes to the eyes. In some embodiments, the different presentations can provide both convergence cues and matching accommodation cues, thus providing a physiologically correct accommodation-convergence match.

[0287] Continuing to refer to Figure 4B, showing two depth planes 240, which correspond to different distances from the eyes 210a, 210b in space. For a given depth plane 240, vergence cues can be provided by displaying appropriate different perspectives of images for each eye 210a, 210b. In addition, for a given depth plane 240, the light forming the images provided to each eye 210a, 210b can have a wavefront divergence corresponding to the light field generated by a point at a distance from the depth plane 240.

[0288] In the illustrated embodiment, the distance along the z-axis of the depth plane 240 containing the point 221 is 1 m. As used herein, the zero point located at the exit pupil of the user's eyes can be utilized to measure the distance or depth along the z-axis. Thus, the depth plane 240 located at a depth of 1 m is at a distance of 1 m from the exit pupil of the user's eyes along the visual axis of these eyes, where the eyes are directed to optical infinity. As an approximation, the depth or distance along the z-axis can be measured as: the distance starting from a display in front of the user's eyes (e.g., from the surface of the waveguide) plus the distance value between the device and the exit pupil of the user's eyes. This value can be referred to as the exit pupil distance and corresponds to the distance between the exit pupil of the user's eyes and the display worn by the user in front of the eyes. In practice, the exit pupil distance value can be a standardized value typically used for all viewers. For example, the exit pupil distance is 20 mm, and the depth plane at a depth of 1 m can be located at a distance of 980 mm in front of the display.

[0289] Now refer to Figure 4C and Figure 4D , which respectively show examples of matched accommodation and vergence distances and mismatched accommodation and vergence distances. As Figure 4C shown, the display system can provide images of virtual objects to each eye 210a, 210b. The image can cause the eyes 210a, 210b to assume a vergence state in which the eyes converge on the point 15 on the depth plane 240. Additionally, the image can be formed by light having a wavefront curvature corresponding to a real object at the depth plane 240. Thus, the eyes 210a, 210b assume an accommodation state in which the image is focused on the retinas of these eyes. Thus, the user can perceive the virtual object to be located at the point 15 on the depth plane 240.

[0290] It should be understood that each of the accommodation state and the vergence state of the eyes 210a, 210b is associated with a specific distance on the z-axis. For example, an object at a specific distance from the eyes 210a, 210b causes these eyes to assume a specific accommodation state based on the distance of the object. The distance associated with a specific accommodation state can be referred to as the accommodation distance A dSimilarly, there is a specific vergence distance V associated with the eyes in a particular vergence state or positions relative to each other. d When the accommodation distance and the vergence distance match, the relationship between accommodation and vergence can be considered physiologically correct. For a viewer, this is considered the most comfortable situation.

[0291] However, in a stereoscopic display, the accommodation distance and the vergence distance may not always match. For example, as Figure 4D shown, the images presented to eyes 210a, 210b can be presented by wavefront divergence corresponding to depth plane 240, and eyes 210a, 210b can assume a particular accommodation state in which they are focused on points 15a, 15b on that depth plane. However, the images presented to eyes 210a, 210b may provide vergence cues that cause eyes 210a, 210b to converge on point 15 which is not located on depth plane 240. Thus, in some embodiments, the accommodation distance corresponds to the distance from the exit pupils of eyes 210a, 210b to depth plane 240, while the vergence distance corresponds to the greater distance from the exit pupils of eyes 210a, 210b to point 15. The accommodation distance is different from the vergence distance. Thus, there is an accommodation-vergence mismatch. This mismatch is considered undesirable and may cause discomfort to the user. It should be understood that the mismatch corresponds to a distance (e.g., V d -A d ) and can be characterized using diopters.

[0292] In some embodiments, it should be understood that reference points other than the exit pupils of eyes 210a, 210b can be used to determine the distances for determining the accommodation-vergence mismatch, as long as the same reference point is used for both the accommodation distance and the vergence distance. For example, the distance from the cornea to the depth plane, from the retina to the depth plane, from the eyepiece (e.g., the waveguide of the display device) to the depth plane, etc. can be measured.

[0293] Without being bound by theory, it can be considered that in situations where the mismatch itself does not cause significant discomfort, a user can still perceive accommodation-vergence mismatches of up to about 0.25 diopters, up to about 0.33 diopters, and up to about 0.5 diopters as being physiologically correct. In some embodiments, the display system (e.g., Figure 6 display system 250) disclosed herein presents images to a viewer having an accommodation-vergence mismatch of about 0.5 diopters or less. In some other embodiments, the accommodation-vergence mismatch of the images provided by the display system is about 0.33 diopters or less. In still other embodiments, the accommodation-vergence mismatch of the images provided by the display system is about 0.25 diopters or less, including about 0.1 diopters or less.

[0294] Figure 5 Aspects of a method for simulating three-dimensional images by modifying wavefront divergence are shown. The display system includes a waveguide 270 configured to receive light 770 encoded with image information and output the light to a user's eye 210. The waveguide 270 may output light 650 having a defined amount of wavefront divergence corresponding to the wavefront divergence of the light field generated by points on a desired depth plane 240. In some embodiments, the same amount of wavefront divergence is provided for all objects presented on the depth plane. Additionally, it will be shown that image information from a similar waveguide may be provided to the user's other eye.

[0295] In some embodiments, a single waveguide may be configured to output light having a set amount of wavefront divergence corresponding to the wavefront divergence of a single depth plane or a limited number of depth planes, and / or the waveguide may be configured to output light within a limited wavelength range. Thus, in some embodiments, a waveguide stack may be used to provide different amounts of wavefront divergence and / or output different wavelength ranges of light for different depth planes. As used herein, it should be understood that at a depth plane, the contour of a plane or a curved surface may be followed. In some embodiments, for simplicity, the depth plane may advantageously follow the contour of a plane.

[0296] Figure 6 An example of a waveguide stack for outputting image information to a user is shown. The display system 250 includes a waveguide stack or stacked waveguide assembly 260 that may be used to provide a three-dimensional perception to the eye / brain using waveguides 270, 280, 290, 300, 310. It should be understood that in some embodiments, the display system 250 may be considered a light field display. Additionally, the waveguide assembly 260 may also be referred to as an eyepiece.

[0297] In some embodiments, the display system 250 may be configured to provide substantially continuous vergence cues and multiple discontinuous accommodation cues. Vergence cues may be provided by displaying different images to each of the user's eyes, and accommodation cues may be provided by outputting light that forms an image with an optional discrete amount of wavefront divergence. In other words, the display system 250 may be configured to output light having a variable wavefront divergence level. In some embodiments, each discrete wavefront divergence level corresponds to a specific depth plane and may be provided by a specific one of the waveguides 270, 280, 290, 300, 310.

[0298] Continuing to refer to Figure 6, the waveguide assembly 260 may also include features 320, 330, 340, 350 located between the waveguides. In some embodiments, the features 320, 330, 340, 350 may be one or more lenses. The waveguides 270, 280, 290, 300, 310 and / or the features (such as lenses) 320, 330, 340, 350 may be configured to send image information to the eye at various wavefront curvature levels or light divergence levels. Each waveguide level may be associated with a particular depth plane and may be configured to output image information corresponding to that depth plane. The image injection devices 360, 370, 380, 390, 400 may be used as light sources for the waveguides and may be used to inject image information into the waveguides 270, 280, 290, 300, 310. As described herein, each waveguide may be configured to distribute incident light across each corresponding waveguide for output toward the eye 210. Light exits from the output surfaces 410, 420, 430, 440, 450 of the image injection devices 360, 370, 380, 390, 400 and is injected into the corresponding input surfaces 460, 470, 480, 490, 500 of the waveguides 270, 280, 290, 300, 310. In some embodiments, each of the input surfaces 460, 470, 480, 490, 500 may be an edge of the corresponding waveguide or may be a part of the major surface of the corresponding waveguide (i.e., one of the waveguide surfaces directly facing the world 510 or the viewer's eye 210). In some embodiments, a single light beam (such as a collimated beam) may be injected into each waveguide so as to output a clone collimated beam directed toward the eye 210 with a specific angle (and divergence amount) corresponding to the depth plane associated with the specific waveguide across the entire field of view. In some embodiments, one of the image injection devices 360, 370, 380, 390, 400 may be associated with one or more (three) waveguides 270, 280, 290, 300, 310 and inject light into these waveguides.

[0299] In some embodiments, the image injection devices 360, 370, 380, 390, 400 are discrete displays, each discrete display generating image information for injection into the corresponding waveguides 270, 280, 290, 300, 310, respectively. In some other embodiments, the image injection devices 360, 370, 380, 390, 400 are output terminals of a single multiplexed display that may pipe image information to each of the image injection devices 360, 370, 380, 390, 400 via one or more optical conduits (such as fiber optic cables), for example. It will be understood that the image information provided by the image injection devices 360, 370, 380, 390, 400 may include light of different wavelengths or colors (such as the different component colors discussed herein).

[0300] In some embodiments, the light injected into waveguides 270, 280, 290, 300, 310 is provided by a light projector system 520, which includes a light module 530 that may include a light emitter such as a light emitting diode (LED). The light from the light module 530 may be directed via a beam splitter 550 to a light modulator 530 (e.g., a spatial light modulator) and modified by the light modulator 530. The light modulator 530 may be configured to change the perceived intensity of the light in the injected waveguides 270, 280, 290, 300, 310 to encode the light with image information. Examples of spatial light modulators include liquid crystal displays (LCDs), which include liquid crystal on silicon (LCOS) displays. It should be understood that the image injection devices 360, 370, 380, 390, 400 are schematically shown, and in some embodiments, these image injection devices may represent different optical paths and positions in a common projection system configured to output light into one of the associated waveguides 270, 280, 290, 300, 310. In some embodiments, the waveguides of the waveguide assembly 260 may act as ideal lenses while relaying the light in the injected waveguides out to the user's eye. In this concept, the object may be the spatial light modulator 540, and the image may be an image on a depth plane.

[0301] In some embodiments, the display system 250 may be a scanned fiber optic display that includes one or more scanned optical fibers configured to project light into one or more waveguides 270, 280, 290, 300, 310 and ultimately to the viewer's eye 210 in various patterns (e.g., raster scan, helical scan, Lissajous pattern, etc.). In some embodiments, the illustrated image injection devices 360, 370, 380, 390, 400 may schematically represent a single scanned optical fiber or a bundle of scanned optical fibers configured to inject light into one or more of the waveguides 270, 280, 290, 300, 310. In some other embodiments, the illustrated image injection devices 360, 370, 380, 390, 400 may schematically represent one or more scanned optical fibers or one or more bundles of scanned optical fibers, each of which is configured to inject light into one of the associated waveguides 270, 280, 290, 300, 310. It should be understood that one or more optical fibers may be configured to transmit light from the light module 530 to one or more waveguides 270, 280, 290, 300, 310. It should be understood that one or more intermediate optical structures may be provided between the one or more scanned optical fibers and the one or more waveguides 270, 280, 290, 300, 310 to, for example, redirect the light exiting the scanned optical fibers into the one or more waveguides 270, 280, 290, 300, 310.

[0302] The controller 560 controls the operation of one or more of the stacked waveguide assemblies 260, including the operation of the image injection devices 360, 370, 380, 390, 400, the light source 530, and the light modulator 540. In some embodiments, the controller 560 is part of the local data processing module 140. The controller 560 includes programming (e.g., instructions in a non-transitory medium) that regulates the timing and provision of image information to waveguides 270, 280, 290, 300, 310 according to any of the various schemes disclosed herein, for example. In some embodiments, the controller can be a single integrated device or a distributed system connected via wired or wireless communication channels. In some embodiments, the controller 560 can be part of the processing module 140 or 150( [[ID=9 ).

[0303] Continuing reference ​, waveguides 270, 280, 290, 300, 310 can be configured to propagate light within each respective waveguide by total internal reflection (TIR). Waveguides 270, 280, 290, 300, 310 can each be planar or have another shape (e.g., curved), having a top major surface and a bottom major surface and an edge extending between these top and bottom major surfaces. In the illustrated configuration, waveguides 270, 280, 290, 300, 310 can each include outcoupling optical elements 570, 580, 590, 600, 610 that are configured to extract light from the waveguide by redirecting the light propagating within each respective waveguide out of the waveguide, thereby outputting image information to the eye 210. Although referred to herein as "outcoupling optical elements", the outcoupling optical elements need not be optical elements and can also be non-optical elements. The extracted light can also be referred to as outcoupled light, and the outcoupling optical elements can also be referred to as light extraction optical elements. At the location where the light propagating in the waveguide illuminates the light extraction optical element, the extracted light beam can be output by the waveguide. As further discussed herein, the outcoupling optical elements 570, 580, 590, 600, 610 can be, for example, gratings that include diffractive optical features. Although shown for ease of description and clarity of illustration to be disposed at the bottom major surface of waveguides 270, 280, 290, 300, 310, in some embodiments, as further discussed herein, the outcoupling optical elements 570, 580, 590, 600, 610 can be disposed at the top major surface and / or the bottom major surface, and / or can be disposed directly within the body of waveguides 270, 280, 290, 300, 310. In some embodiments, the outcoupling optical elements 570, 580, 590, 600, 610 can be formed in a material layer attached to a transparent substrate, thereby forming waveguides 270, 280, 290, 300, 310. In some other embodiments, waveguides 270, 280, 290, 300, 310 can be a single-piece material, and the outcoupling optical elements 570, 580, 590, 600, 610 can be formed on and / or within the surface of the piece of material.

[0304] Continue to refer to ​, as discussed herein, each of waveguides 270, 280, 290, 300, 310 is configured to output light to form an image corresponding to a particular depth plane. For example, the waveguide 270 closest to the eye may be configured to transmit collimated light injected into this waveguide 270 to the eye 210. The collimated light may represent an optically infinite focal plane. The next upstream waveguide 280 may be configured to emit collimated light that propagates through a first lens 350 (e.g., a negative lens) before reaching the eye 210; such a first lens 350 may be configured to produce a slightly convex wavefront curvature such that the eye / brain interprets the light from the next upstream waveguide 280 as coming from a first focal plane that is closer to the eye 210 inward from the optically infinite. Similarly, the third upstream waveguide 290 passes its output light through the first lens 350 and the second lens 340 before reaching the eye 210. The combined optical power of the first lens 350 and the second lens 340 may be configured to produce another increment in wavefront curvature such that the eye / brain interprets the light from the third waveguide 290 as light from a second focal plane that is closer to the person inward from the optically infinite than the light from the next upstream waveguide 280.

[0305] The other waveguide layers 300, 310 and lenses 330, 320 are configured similarly, where the highest waveguide 310 in the stack sends its output through all of the lenses between it and the eye to obtain an aggregate focal power representative of the focal plane closest to the person. To compensate for the lens stack 320, 330, 340, 350 when viewing / interpreting light from the world 510 on the other side of the stacked waveguide assembly 260, a compensating lens layer 620 may be provided at the top of the stack to compensate for the total focal power of the underlying lens stack 320, 330, 340, 350. This configuration provides as many perceived focal planes as there are available waveguide / lens pairings. Both the outcoupling optical elements of the waveguides and the focusing aspects of the lenses can be static (i.e., not dynamic or electroactive). In some alternative embodiments, one or both of them can be dynamic by using electroactive features.

[0306] In some embodiments, two or more of the waveguides 270, 280, 290, 300, 310 may have the same associated depth plane. For example, multiple waveguides 270, 280, 290, 300, 310 may be configured to output a set of images to the same depth plane, or multiple subsets of the waveguides 270, 280, 290, 300, 310 may be configured to output a set of images to the same one or more depth planes, one set of images per depth plane. This can provide the advantage of forming a stitched image to provide an extended field of view at those depth planes.

[0307] Continuing to refer to ​, the out-coupling optical elements 570, 580, 590, 600, 610 can be configured to redirect light out of their respective waveguides and output the light with an appropriate amount of divergence or collimation for a particular depth plane associated with the waveguide. Thus, waveguides having different associated depth planes can have different configurations of out-coupling optical elements 570, 580, 590, 600, 610, and these out-coupling elements output light with different amounts of divergence depending on the associated depth plane. In some embodiments, the light extraction optical elements 570, 580, 590, 600, 610 can be volume features or surface features that can be configured to output light at a particular angle. For example, the light extraction optical elements 570, 580, 590, 600, 610 can be volume holograms, surface holograms, and / or diffraction gratings. In some embodiments, the features 320, 330, 340, 350 can not be lenses; instead, they can be merely spacers (e.g., cladding and / or structures for forming air gaps).

[0308] In some embodiments, the out-coupling optical elements 570, 580, 590, 600, 610 are diffraction features that form a diffraction pattern, or "diffractive optical elements" (also referred to herein as "DOEs"). Preferably, the DOE has a low enough diffraction efficiency such that only a portion of the light beam is deflected toward the eye 210 through each intersection of the DOE, while the remainder continues to travel through the waveguide via TIR. Thus, the light carrying the image information is split into multiple related outgoing beams that exit the waveguide at multiple locations, resulting in a fairly uniform outgoing pattern toward the eye 210 for a particular collimated beam bouncing around within the waveguide.

[0309] In some embodiments, one or more DOEs can be switchable between an "on" state in which they actively diffract and an "off" state in which they do not significantly diffract. For example, a switchable DOE can include a polymer dispersed liquid crystal layer in which microdroplets include a diffraction pattern in a host medium, and the refractive index of the microdroplets can be switched to substantially match the refractive index of the host material (in which case the pattern does not significantly diffract the incident light), or the microdroplets can be switched to a refractive index that does not match the refractive index of the host medium (in which case the pattern actively diffracts the incident light).

[0310] In some embodiments, a camera component 630 (e.g., a digital camera, including visible light and infrared cameras) may be provided to capture images of the eye 210 and / or the tissue surrounding the eye 210, for example, to detect user input and / or monitor the user's physiological state. As used herein, a camera may be any image capture device. In some embodiments, the camera component 630 may include an image capture device and a light source that projects light (e.g., infrared light) onto the eye, which may then be reflected by the eye and detected by the image capture device. In some embodiments, the camera component 630 may be attached to the frame 80( ​ ) and may be in electrical communication with the processing module 140 and / or 150, which may process the image information from the camera component 630. In some embodiments, one camera component 630 may be used for each eye to monitor each eye separately.

[0311] Now referring to ​ , an example of an output beam exiting the waveguide is shown. One waveguide is shown, but it should be understood that other waveguides in the waveguide assembly 260( ​ ) may function similarly, where the waveguide assembly 260 includes a plurality of waveguides. Light 640 is injected into the waveguide 270 at the input surface 460 of the waveguide 270 and propagates within the waveguide 270 by TIR. At the point where the light 640 illuminates the DOE 570, a portion of the light exits the waveguide as an output beam 650. The output beam 650 is illustrated as being substantially parallel, but as discussed herein, depending on the depth plane associated with the waveguide 270, the output beam 650 may also be redirected at an angle (e.g., to form a diverging output beam) to propagate to the eye 210. It should be understood that a substantially parallel output beam may indicate a waveguide having a coupling-out optical element that couples out light to form an image that appears to be disposed on a depth plane at a relatively large distance (e.g., optical infinity) from the eye 210. Other waveguides or other sets of coupling-out optical elements may output a more diverging output beam pattern, which would require the eye 210 to accommodate to a closer distance to focus it on the retina, and these beam patterns may be interpreted by the brain as light from a distance closer to the eye 210 than optical infinity.

[0312] In some embodiments, a full-color image may be formed at each depth plane by superimposing images in each component color (e.g., three or more component colors). ​An example of a stacked waveguide assembly is shown, where each depth plane includes an image formed using a plurality of different component colors. The illustrated embodiment shows depth planes 240a through 240f, although more or fewer depths can be envisioned. Each depth plane can have three or more component color images associated therewith, including: a first image of a first color G; a second image of a second color R; and a third image of a third color B. Different numbers of diopters (dpt) after the letters G, R, and B in the figure represent different depth planes. For example, the number following each letter represents the diopter (1 / m), or the reciprocal of the distance of that depth plane from the viewer, and each box in the figure represents a separate component color image. In some embodiments, to account for differences in the focusing of the eye for different wavelengths of light, the precise placement of the depth planes of different component colors can vary. For example, the different component color images of a given depth plane can be placed on depth planes corresponding to different distances from the user. Such an arrangement can increase visual acuity and user comfort and / or can reduce chromatic aberration.

[0313] In some embodiments, light of each component color can be output by a single dedicated waveguide, and thus, each depth plane can have a plurality of waveguides associated therewith. In such embodiments, each box in the figure that includes the letter G, R, or B can be understood to represent a separate waveguide, and three waveguides can be provided for each depth plane, where three component color images are provided for each depth plane. Although, for ease of description, the waveguides associated with each depth plane are shown adjacent to each other in the figure, it should be understood that in a physical device, the waveguides can all be arranged as a stack of one waveguide per tier. In some other embodiments, a plurality of component colors can be output by the same waveguide such that, for example, only a single waveguide can be provided for each depth plane.

[0314] Continuing to refer to ​ , in some embodiments, G is green, R is red, and B is blue. In some other embodiments, in addition to red, green, or blue, other colors associated with light of other wavelengths (including magenta and cyan) can be used, or these colors can replace one or more of red, green, or blue.

[0315] It should be understood that references throughout this disclosure to light of a given color will be understood to include light of one or more wavelengths within the wavelength range of light that is perceived by a viewer as having that given color. For example, red light can include light of one or more wavelengths in the range of approximately 620 nm to 780 nm, green light can include light of one or more wavelengths in the range of approximately 492 nm to 577 nm, and blue light can include light of one or more wavelengths in the range of approximately 435 nm to 493 nm.

[0316] In some embodiments, the light source 530 ( ​ ) may be configured to emit light at one or more wavelengths outside the viewer's visual perception range (e.g., infrared and / or ultraviolet wavelengths). Additionally, the light coupling, decoupling, and other light redirecting structures of the waveguide of the display 250 may be configured to direct the light out of the display and emit it towards the user's eye 210, e.g., for imaging and / or user stimulation applications.

[0317] Now referring to ​ , in some embodiments, it may be necessary to redirect the light incident on the waveguide to couple the light into the waveguide. A coupling optical element may be used to redirect the light and couple the light into its corresponding waveguide. Although referred to as a "coupling optical element" in the specification, the coupling optical element need not be an optical element and may also be a non-optical element. ​ A cross-sectional side view of an example of a stacked waveguide group 660 is shown, each stacked waveguide including a coupling optical element. The waveguides may each be configured to output light at one or more different wavelengths, or one or more different wavelength ranges. It should be understood that the stack 660 may correspond to the stack 260 ( ​ ) except that light from one or more of the image injection devices 360, 370, 380, 390, 400 is injected into the waveguide at a location where the light needs to be redirected for coupling, and the waveguides of the stack 660 shown may correspond to a portion of the waveguides 270, 280, 290, 300, 310.

[0318] The stacked waveguide group 660 shown includes waveguides 670, 680, and 690. Each waveguide includes an associated optical coupling element (which may also be referred to as an optical input region on the waveguide), where, for example, the optical coupling element 700 disposed on the main surface (e.g., the top main surface) of the waveguide 670, the optical coupling element 710 disposed on the main surface (e.g., the top main surface) of the waveguide 680, and the optical coupling element 720 disposed on the main surface (e.g., the top main surface) of the waveguide 690. In some embodiments, one or more of the optical coupling elements 700, 710, 720 may be disposed on the bottom main surface of the corresponding waveguides 670, 680, 690 (especially in the case where one or more of the optical coupling elements are reflective deflecting optical elements). As shown, the optical coupling elements 700, 710, 720 may be disposed on the top main surface (or the top of the next lower waveguide layer) of their corresponding waveguides 670, 680, 690, especially in the case where those optical coupling elements are transmissive deflecting optical elements. In some embodiments, the optical coupling elements 700, 710, 720 may be disposed within the bodies of the corresponding waveguides 670, 680, 690. In some embodiments, as discussed herein, the optical coupling elements 700, 710, 720 are wavelength selective such that they selectively redirect light of one or more wavelengths while transmitting light of other wavelengths. Although shown on one side or corner of their corresponding waveguides 670, 680, 690, it should be understood that in some embodiments, the optical coupling elements 700, 710, 720 may be disposed in other regions of their corresponding waveguides 670, 680, 690.

[0319] As shown, the optical coupling elements 700, 710, 720 may be laterally offset from each other. In some embodiments, each optical coupling element may be offset such that the optical coupling element receives light that does not need to propagate through another optical coupling element. For example, each of the optical coupling elements 700, 710, 720 may be configured to receive light from different image injection devices 360, 370, 380, 390, and 400, as ​ shown, and may be separated (e.g., laterally spaced apart) from the other optical coupling elements 700, 710, 720 such that the optical coupling element substantially does not receive light from the other optical coupling elements among the optical coupling elements 700, 710, 720.

[0320] Each waveguide also includes an associated optical distribution element. For example, an optical distribution element 730 disposed on the main surface (e.g., the top main surface) of waveguide 670, an optical distribution element 740 disposed on the main surface (e.g., the top main surface) of waveguide 680, and an optical distribution element 750 disposed on the main surface (e.g., the top main surface) of waveguide 690. In some other embodiments, the optical distribution elements 730, 740, 750 may be respectively disposed on the bottom main surfaces of the associated waveguides 670, 680, 690. In some other embodiments, the optical distribution elements 730, 740, 750 may be respectively disposed on the top main surfaces and the bottom main surfaces of the associated waveguides 670, 680, 690; or, the optical distribution elements 730, 740, 750 may be respectively disposed on different surfaces among the top main surfaces and the bottom main surfaces of different associated waveguides 670, 680, 690.

[0321] The waveguides 670, 680, 690 may be separated and spaced apart by, for example, gas, liquid, and / or solid material layers. For example, as shown, layer 760a may separate waveguides 670 and 680; layer 760b may separate waveguides 680 and 690. In some embodiments, layers 760a and 760b are formed of a low refractive index material (i.e., a material having a refractive index lower than that of the material forming the adjacent waveguides among waveguides 670, 680, 690). Preferably, the refractive index of the material forming layers 760a, 760b is smaller than the refractive index of the material forming waveguides 670, 680, 690 by 0.05 or more, or by 0.10 or more. Advantageously, the lower refractive index layers 760a, 760b can act as claddings, which contribute to total internal reflection (TIR) of light through waveguides 670, 680, 690 (e.g., TIR between the top main surface and the bottom main surface of each waveguide). In some embodiments, layers 760a, 760b are formed of air. Although not shown, it should be understood that the top and bottom of the shown waveguide group 660 may include adjacent claddings.

[0322] Preferably, for ease of fabrication and other considerations, the materials forming waveguides 670, 680, 690 are similar or the same, and the materials forming layers 760a, 760b are similar or the same. In some embodiments, the materials forming waveguides 670, 680, 690 may be different between one or more waveguides, and / or the materials forming layers 760a, 760b may be different, while still maintaining the various refractive index relationships described above.

[0323] Continuing to refer to ​ , light rays 770, 780, 790 are incident on the waveguide group 660. It should be understood that the light rays 770, 780, 790 may pass through one or more image injection devices 360, 370, 380, 390, 400 (​ ) into the injection waveguides 670, 680, 690.

[0324] In some embodiments, the light rays 770, 780, 790 have different characteristics, for example, different wavelengths or different wavelength ranges, and these different wavelengths or wavelength ranges may correspond to different colors. The coupling optical elements 700, 710, 720 each deflect the incident light so that the light propagates through the corresponding one of the waveguides 670, 680, 690 by TIR. In some embodiments, the coupling optical elements 700, 710, 720 selectively deflect light of one or more specific wavelengths, while transmitting other wavelengths to the underlying waveguides and associated coupling optical elements.

[0325] For example, the coupling optical element 700 may be configured to deflect the light ray 770 having a first wavelength or wavelength range, while transmitting the light rays 780 and 790 having different second and third wavelengths or wavelength ranges, respectively. The transmitted light ray 780 impinges on the coupling optical element 710 and is deflected by it, and the coupling optical element 710 is configured to deflect the light of the second wavelength or wavelength range. The light ray 790 is deflected by the coupling optical element 720, and the coupling optical element 720 is configured to selectively deflect the light of the third wavelength or wavelength range.

[0326] Continuing to refer to ​ , the deflected light rays 770, 780, 790 are deflected so that they propagate through the corresponding waveguides 670, 680, 690; that is, the coupling optical elements 700, 710, 720 of each waveguide deflect the light into the corresponding waveguides 670, 680, 690 to couple the light into the corresponding waveguide. The light rays 770, 780, 790 are deflected at an angle such that the light propagates through the corresponding waveguides 670, 680, 690 by TIR. The light rays 770, 780, 790 propagate through the corresponding waveguides 670, 680, 690 by TIR until they impinge on the corresponding light distribution elements 730, 740, 750 of the waveguide.

[0327] Now referring to ​ , a perspective view of an example of a stacked waveguide of ​ is shown. As described above, the coupled light rays 770, 780, 790 are respectively deflected by the coupling optical elements 700, 710, 720 and then propagate through the waveguides 670, 680, 690 by TIR, respectively. Then, the light rays 770, 780, 790 respectively impinge on the light distribution elements 730, 740, 750. The light distribution elements 730, 740, 750 deflect the light rays 770, 780, 790 so that the light rays 770, 780, 790 respectively propagate toward the coupling-out optical elements 800, 810, 820.

[0328] In some embodiments, the light distribution elements 730, 740, 750 are orthogonal pupil expanders (OPEs). In some embodiments, the OPE deflects or distributes light to the light extraction optical elements 800, 810, 820, and in some embodiments, it can also increase the beam or spot size of the light as it propagates to the light extraction optical elements. In some embodiments, the light distribution elements 730, 740, 750 can be omitted, and the light coupling optical elements 700, 710, 720 can be configured to deflect light directly to the light extraction optical elements 800, 810, 820. For example, referring to ​ , the light distribution elements 730, 740, 750 can be replaced by the light extraction optical elements 800, 810, 820, respectively. In some embodiments, the light extraction optical elements 800, 810, 820 are exit pupils (EPs) or exit pupil expanders (EPEs), which direct light into the eye 210 ( ​ ). It should be understood that the OPE can be configured to increase the size of the eye box in at least one axis, and the EPE can increase the eye box in an axis that intersects (e.g., is orthogonal to) the axis of the OPE. For example, each OPE can be configured to redirect a portion of the light illuminating the OPE to the EPE of the same waveguide while allowing the remaining portion of the light to continue propagating along the waveguide. When the remaining light illuminates the OPE again, another portion of the remaining light is redirected to the EPE, and the remaining portion of that portion continues to propagate further along the waveguide, and so on. Similarly, when illuminating the EPE, a portion of the illuminating light is directed out of the waveguide towards the user, and the remaining portion of the light continues to propagate through the waveguide until it illuminates the EP again, at which point another portion of the illuminating light is directed out of the waveguide, and so on. Thus, whenever a portion of the light is redirected by the OPE or EPE, a single coupled-in light beam can be "copied", thereby forming a field of the cloned light beams, as shown in ​ . In some embodiments, the OPE and / or EPE can be configured to modify the size of the light beam.

[0329] Therefore, referring to ​ and ​, in some embodiments, the waveguide group 660 includes waveguides 670, 680, 690 for each component color; input optical elements 700, 710, 720; light distribution elements (such as OPEs) 730, 740, 750; and output optical elements (such as EPs) 800, 810, 820. The waveguides 670, 680, 690 may be stacked such that there is an air gap / cladding between each waveguide. The input optical elements 700, 710, 720 redirect or deflect the incident light (where different input optical elements receive light of different wavelengths) into their waveguides. The light then propagates at an angle, which results in TIR within the corresponding waveguides 670, 680, 690. In the example shown, the light ray 770 (such as blue light) is deflected by the first input optical element 700 in the previously described manner and then continues to bounce along the waveguide, interacting with the light distribution element (such as OPE) 730 and then the output optical element (such as EP) 800. The light rays 780 and 790 (such as green light and red light, respectively) will propagate through the waveguide 670, where the light ray 780 impinges on the input optical element 710 and is deflected by the input optical element 710. The light ray 780 then bounces along the waveguide 680 via TIR, proceeds to its light distribution element (such as OPE) 740, and then reaches the output optical element (such as EP) 810. Finally, the light ray 790 (such as red light) propagates through the waveguide 690 and impinges on the input optical element 720 of the waveguide 690. The light input optical element 720 deflects the light ray 790 such that the light ray propagates to the light distribution element (such as OPE) 750 via TIR and then to the output optical element (such as EP) 820 via TIR. Then, the output optical element 820 finally couples out the light ray 790 to the viewer, and the viewer also receives the output light from the other waveguides 670, 680.

[0330] ​ shows ​ and ​ A top plan view of an example of a plurality of stacked waveguides. As shown, the waveguides 670, 680, 690 and the associated light distribution elements 730, 740, 750 of each waveguide and the associated output optical elements 800, 810, 820 may be vertically aligned. However, as discussed herein, the input optical elements 700, 710, 720 are not vertically aligned; rather, the input optical elements are preferably non-overlapping (e.g., laterally spaced apart as shown in the top view). As further discussed herein, this non-overlapping spatial arrangement helps to inject light from different sources into different waveguides one-to-one, thereby allowing a specific light source to be uniquely coupled to a specific waveguide. In some embodiments, an arrangement including non-overlapping spatially separated input optical elements may be referred to as a shifted pupil system, and the input optical elements within these arrangements may correspond to sub-pupils.

[0331] ​ Shows an example of a wearable display system 60 that can integrate various waveguides and related systems disclosed herein. In some embodiments, the display system 60 is ​ system 250, where ​ Some parts of the system 60 are shown schematically in more detail. For example, ​ The waveguide assembly 260 can be part of the display 70.

[0332] Continuing to refer to ​ , the display system 60 includes a display 70, as well as various mechanical and electronic modules and systems that support the functions of the display 70. The display 70 can be coupled to a frame 80 that can be worn by a user or viewer 90 of the display system and is configured to position the display 70 in front of the eyes of the user 90. In some embodiments, the display 70 can be considered glasses. In some embodiments, a speaker 100 is coupled to the frame 80 and is configured to be positioned near the ear canal of the user 90 (in some embodiments, another speaker (not shown) can be selectively positioned near the other ear canal of the user to provide stereo / plastic sound control). The display system 60 can also include one or more microphones 110 or other sound-detecting devices. In some embodiments, the microphone is configured to allow the user to provide input or commands to the system 60 (such as selection of voice menu commands, natural language questions, etc.), and / or can allow audio communication with other people (such as other users of a similar display system). The microphone can be further configured as a peripheral sensor to collect audio data (such as sounds from the user and / or the environment). In some embodiments, the display system 60 can further include one or more outward-facing environmental sensors 112 configured to detect objects, stimuli, people, animals, locations, or other aspects of the world around the user. For example, the environmental sensors 112 can include one or more cameras that can be positioned facing outward, for example, to capture images similar to at least a portion of the general field of view of the user 90. In some embodiments, the display system can also include a peripheral sensor 120a that can be separated from the frame 80 and attached to the body of the user 90 (such as on the head, torso, limbs, etc. of the user 90). In some embodiments, the peripheral sensor 120a can be configured to acquire data characterizing the physiological state of the user 90. For example, the sensor 120a can be an electrode.

[0333] Continuing to refer to ​, the display 70 is operatively coupled to the local data processing module 140 via a communication link 130 (such as via a wired lead or a wireless connection). The local data processing module 140 can be installed in various configurations, such as fixedly attached to the frame 80, fixedly attached to a helmet or hat worn by the user, embedded in the earphone, or otherwise removably attached to the user 90 (e.g., in a backpack configuration, in a strap-coupled configuration). Similarly, the sensor 120a can be operatively coupled to the local processing and data module 140 via a communication link 120b (e.g., via a wired lead or a wireless connection). The local processing and data module 140 can include a hardware processor and a digital memory, such as a non-volatile memory (e.g., flash memory or hard disk drive), both of which can be used to assist in the processing, caching, and storage of data. Optionally, the local processor and data module 140 can include one or more central processing units (CPUs), graphics processing units (GPUs), dedicated processing hardware, etc. Such data includes a) data captured by sensors (which can be operatively coupled to the frame 80 or otherwise attached to the user 90), such as image capture devices (such as cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, radio devices, gyroscopes, and / or other sensors disclosed herein; and / or b) data obtained and / or processed using the remote processing module 150 and / or the remote data repository 160 (including data related to virtual content), which may be transmitted to the display 70 after such processing or retrieval is completed. The local processing and data module 140 can be operatively coupled to the remote processing module 150 and the remote data repository 160 via communication links 170, 180 (such as via wired or wireless communication links) such that these remote modules 150, 160 are operatively coupled to each other and are available as resources to the local processing and data module 140. In some embodiments, the local processing and data module 140 can include one or more of an image capture device, a microphone, an inertial measurement unit, an accelerometer, a compass, a GPS unit, a radio device, and / or a gyroscope. In some other embodiments, one or more of these sensors can be attached to the frame 80 or can be independent structures communicating with the local processing and data module 140 via a wired or wireless communication path.

[0334] Continuing to refer to ​, in some embodiments, the remote processing module 150 may include one or more processors configured to analyze and process data and / or image information. For example, it may include one or more central processing units (CPUs), graphics processing units (GPUs), dedicated processing hardware, etc. In some embodiments, the remote data repository 160 may include a digital data storage facility that can be obtained through the Internet or other network configurations in a "cloud" resource configuration. In some embodiments, the remote data repository 160 may include one or more remote servers that provide information to the local processing and data module 140 and / or the remote processing module 150, such as information for generating augmented reality content. In some embodiments, all data is stored in the local processing and data module and all calculations are performed, allowing for autonomous use from the remote module. Optionally, an external system (such as a system of one or more processors, one or more computers) including a CPU, GPU, etc. may perform at least a portion of the processing (such as generating image information, processing data) and provide information to, and receive information from, modules 140, 150, 160, for example, via a wireless or wired connection.

[0335] ​ FIG. is a schematic diagram showing a projector assembly 1000 that uses a polarization beam splitter (PBS) 1020 to illuminate a spatial light modulator (SLM) 1030 and redirect light from the SLM 1030 through projection optics 1040 to an eyepiece (not shown). The projector assembly 1000 includes an illumination source 1010, which may include, for example, a light emitting diode (LED), a laser (such as a laser diode), or other types of light sources. The light can be collimated by collimation optics. The illumination source 1010 may emit polarized, unpolarized, or partially polarized light. In the illustrated design, the illumination source 1010 may emit polarized light 1012 having p-polarization. The first optical element 1015 (such as a pre-polarizer) is aligned to allow light having a first polarization (such as p-polarization) to pass through.

[0336] The light is directed to a polarization beam splitter 1020. Initially, the light propagates through an interface 1022 (e.g., a polarization interface) of PBS 1020, which is configured to transmit light of a first polarization (e.g., p-polarization). Thus, the light continues to reach the spatial light modulator 1030 and is incident on the spatial light modulator 1030. As shown, SLM 1030 is a reflective SLM, which is configured to retroreflect the incident light and selectively modulate the light. SLM 1030 includes, for example, one or more pixels that can have different states. The light incident on each pixel can be modulated based on the state of the pixel. Thus, SLM 1030 can be driven to modulate the light to provide an image. In this example, SLM 1030 can be a polarization-based SLM that modulates the polarization of the light incident on it. For example, in the on state, the pixels of SLM 1030 change the input light from a first polarization state (e.g., p-polarization state) to a second polarization state (e.g., s-polarization state), thereby showing a bright state (e.g., a white pixel). The second polarization state can be the first polarization state that is modulated (e.g., rotated) by 90°. In the on state, the light having the second polarization state is reflected by the interface 1022 and propagates downward to the projector optics 1040. In the off state, SLM 1030 does not change the polarization state of the light incident on it, e.g., does not rotate the input light from the first polarization state, and thus shows a dark state (e.g., a black pixel). In the off state, the light having the first polarization state transmits through the interface 1022 and propagates upward back to the illumination source 1010 instead of the user's eye.

[0337] After being reflected from SLM 1030, a portion of the light 1014 (e.g., the modulated light) is reflected from the interface 1022 and exits PBS 1020 to be directed to the user's eye. The emitted light propagates through the projector optics 1040 and is imaged onto an input coupling grating (ICG) 1050 of an eyepiece (not shown).

[0338] ​ A system (e.g., an augmented reality display system) 1100A is shown for presenting an image to a user's eye 210 and for viewing the world 510, the system having ​Alternative configurations of the illustrated configuration. System 1100 includes a light source 1110, a spatial light modulator (SLM) 1140, and a waveguide 1120. The system is arranged such that light from the light source 1110 irradiates the SLM 1140, and the light reflected from the SLM 1140 is coupled into the waveguide 1120 to be directed to the eye 210. System 1100A includes an optical device 1130 that is configured to both irradiate the SLM 1140 and project an image of the SLM 1140. For example, light from the light source 1110 propagates in a first direction through the optical device 1130 and reaches the SLM 1140, thereby irradiating the SLM 1140. The light reflected from the SLM 1140 propagates again through the optical device 1130 in a second direction opposite to the first direction, and then is directed to the waveguide 1120 and coupled into the waveguide.

[0339] The light source 1110 may include a light emitting diode (LED), a laser (such as a laser diode), or other types of light sources. The light source 1110 may be a polarized light source, but the light source 1110 is not limited thereto. In some embodiments, a polarizer 1115 may be located between the light source 1110 and the SLM 1140. As shown, the polarizer 1115 is located between the light source 1110 and the waveguide 1120. The polarizer 1115 may also be a light recycler that transmits light of a first polarization and reflects light of a second polarization back to the light source 1110. Such a polarizer 1115 may be, for example, a wire grid polarizer. Coupling optical device 1105, such as a non-imaging optical element (e.g., a compound parabolic concentrator (CPC), a lens), may be disposed relative to the light source 1110 to receive light output from the light source 1110. The coupling optical device 1105 may collect light from the light source 1110 and, in some cases, may reduce the divergence of the light emitted from the light source 1110. The coupling optical device 1105 may, for example, collimate the light output from the light source 1110. The coupling optical device 1105 may collect light that matches the angular spectrum field of view of the system 1100A. Thus, the coupling optical device 1105 may match the angular spectrum of the light output by the light source 1110 to the field of view of the system 1100A. The coupling optical device 1105 may have an asymmetric profile to operate asymmetrically on the light emitted from the light source 1110. For example, the coupling optical device 1105 may reduce divergence by different amounts in orthogonal directions (e.g., the x and z directions). This asymmetry in the coupling optical device 1105 may address the asymmetry in the light emitted from the light source 1110, which may include, for example, a laser diode that emits a wider angular range of light in one direction (e.g., x or z) opposite to an orthogonal direction (e.g., z or x, respectively).

[0340] As described above, system 1100A includes an optical device 1130 in the optical path between a light source 1110 and an SLM 1140, and the optical device 1130 is configured to illuminate the SLM 1140. The optical device 1130 may include a transmissive optical device that transmits light from the light source 1110 to the SLM 1140. The optical device 1130 may also be configured to project an image of the SLM 1140 or an image formed by the SLM 1140 into the waveguide 1120. The image may be projected into the eye 210 inside the eye. In some designs, the optical device 1130 may include one or more lenses or optical elements with optical power. The optical device 1130 may have a positive optical power, for example. The optical device 1130 may include one or more refractive optical elements, such as refractive lenses. Other types of optical elements may also be used.

[0341] The SLM 1140 may be reflective, modulating and reflecting light therefrom. The SLM 1140 may be a polarization-based SLM configured to modulate polarization. The SLM 1140 may include, for example, a liquid crystal (LC) SLM (such as a liquid crystal on silicon (LCOS) SLM). The LC SLM may include, for example, twisted nematic (TN) liquid crystals. The SLM 1140 may be substantially similar to the SLM1030 of the reference ​ . The SLM 1140 may include, for example, one or more pixels configured to selectively modulate light incident on the pixel depending on the pixel state. For some types of SLM 1140, the pixel may modulate the light beam incident thereon, for example, by changing the polarization state, such as rotating the polarization (e.g., rotating the orientation of linearly polarized light).

[0342] As described above, the SLM 1140 may be an LCOS SLM 1140. In a cross-polarizer configuration, the LCOS SLM 1140 may be labeled white. When the pixel is off (e.g., 0 volts), it has a bright state, while when the pixel is on (e.g., a voltage higher than the threshold turn-on voltage), it has a dark state. In this cross-polarization configuration, when the pixel is on and the pixel is in the dark state, the light leakage is minimized.

[0343] In a parallel-polarizer configuration, the LCOS SLM ́1140 is nominally black. When the pixel is off (e.g., 0 volts), it has a dark state, while when the pixel is on (e.g., a voltage higher than the threshold turn-on voltage), it has a bright state. In this parallel-polarizer configuration, when the pixel is off and the pixel is in the dark state, the light leakage is minimized. The rubbing direction and the compensator angle may be used to (re)optimize the dark state. The compensator angle may refer to the angle of the compensator between the optical device 1130 and the SLM1140, for example, as ​ shown.

[0344] The dynamic range and throughput of a parallel polarizer configuration can be different from that of a crossed polarizer configuration. Furthermore, unlike a crossed polarizer configuration, a parallel polarizer configuration can be optimized for contrast.

[0345] System 1100A includes a waveguide 1120 for outputting image information to eye 210. Waveguide 1120 can be substantially similar to waveguides 270, 280, 290, 300, 310, 670, 680, and 690 discussed above. Waveguide 1120 can comprise a substantially transparent material having a refractive index sufficient to guide light within the waveguide. As shown, waveguide 1120 can include a first side 1121 and a second side 1123 opposite first side 1121, as well as corresponding upper and lower major surfaces and surrounding edges. First and second major surfaces 1121, 1123 can be sufficiently flat to preserve image information as light propagates from SLM 1140 toward eye 210, thereby allowing an image formed by SLM 1140 to be injected into the eye. Optics 1130 and SLM 1140 can be located on first side 1121 of waveguide 1120. The light source 1110 may be disposed on the second side 1123 such that light from the light source 1110 is incident on the second side 1123 before propagating through the waveguide 1120 and passing through the optical device 1130 to reach the SLM 1140. Thus, the waveguide 1120 may be disposed between the light source 1110 and the optical device 1130. Additionally, at least a portion of the waveguide 1120 may extend between the light source 1110 and the optical device 1130, whereby the light propagates through a portion of the waveguide 1120 to reach the optical device 1130. Thus, light emitted from the light source 1110 may be guided through the waveguide 1120, enter and pass through the optical device 1130, and be incident on the SLM 1140. The SLM 1140 reflects the light back, causing the light to pass through the optical device 1130 and reach the waveguide 1120.

[0346] The system 1100A also includes a coupling-in optical element 1160 for coupling light from the optical device 1130 into the waveguide 1120. The coupling-in optical element 1160 can be disposed on a major surface of the waveguide 1120 (e.g., the upper major surface 1123). In some designs, the coupling-in optical element 1160 can be disposed on the lower major surface 1121 of the waveguide 1120. In some designs, the coupling-in optical element 1160 can be disposed in the body of the waveguide 1120. Although the coupling-in optical element 1160 is shown as being located on a side or corner of the waveguide 1120, the coupling-in optical element 1160 can also be disposed in / on other areas of the waveguide 1120. The coupling-in optical element 1160 can be based on the above reference ​ 、 ​ and​ The described light-coupling optical elements 700, 710, 720 are similar. The light-coupling optical element 1160 can be a diffractive optical element or a reflector. Other structures can also be used as the light-coupling optical element 1160. The light-coupling optical element 1160 can be configured to guide the light incident thereon into the waveguide 1120 at a sufficiently large grazing angle (e.g., greater than the critical angle) with respect to the upper major surface 1123 and the lower major surface 1121 of the waveguide 1120, so as to guide the light in the waveguide 1120 by total internal reflection. In addition, the light-coupling optical element 1160 can operate in a wide wavelength range, and thus is configured to couple lights of multiple colors into the waveguide 1120. For example, the light-coupling optical element 1160 can be configured to couple red, green, and blue lights into the waveguide 1120. The light source 1110 can emit red, green, and blue lights at different times.

[0347] The system 1100A includes a light distribution element 1170 disposed on or in the waveguide 1120. The light distribution element 1170 can be substantially similar to the light distribution elements 730, 740, and 750 described above with respect to ​ For example, the light distribution element 1170 can be an orthogonal pupil expander (OPE). The light distribution element 1170 can be configured to expand the light within the waveguide 1120 by turning the light propagating in the z direction, for example, toward the ​ as shown in the top view along the x direction. Therefore, the light distribution element 1170 can be configured to increase the size of the eye movement range along the z axis; see ​ . The light distribution element 1170 can include, for example, one or more diffractive optical elements configured to diffract the light incident on the diffractive optical element and propagating in the waveguide 1120, so as to redirect the light in a generally orthogonal direction. Other configurations are also possible.

[0348] As ​ shown, the system 1100A can also include a light-coupling-out optical element 1180 for coupling the light out of the waveguide 1120 to the eye 210. The light-coupling-out optical element 1180 can be configured to redirect the light propagating in the waveguide 1120 at an angle more perpendicular to the upper major surface 1123 and / or the lower major surface 1121 of the waveguide 1120 by total internal reflection (TIR), so that the light is not guided within the waveguide 1120. Instead, the light is guided out of the waveguide 1120 through, for example, the lower major surface 1121. The light-coupling-out optical element 1180 can include, for example, one or more diffractive optical elements configured to diffract the light incident on the diffractive optical element and propagating in the waveguide 1120, so as to redirect the light out of the waveguide 1120. Other configurations are also possible.

[0349] ​Also shown is the position of the light-incoupling optical element 1160 disposed laterally with respect to the light distribution optical element (e.g., an orthogonal pupil expander) 1170 and the light-extracting optical element 1180. ​ Also shown is the position of the light source 1110 disposed laterally with respect to the light-incoupling optical element 1160, the light distribution optical element (e.g., an orthogonal pupil expander) 1170, and the light-extracting optical element 1180.

[0350] In operation, the light source 1110 of the system 1100A emits light into the coupling optics 1105 and through the polarizer 1115. Thus, the light can be polarized, e.g., linearly polarized in a first direction. The polarized light can transmit through the waveguide 1120, enter the second major surface of the waveguide 1120, and exit from the first major surface of the waveguide 1120. The light can propagate through the optics 1130 to the SLM 1140. The optics 1130 collimates and / or selects the light from the light source 1110 to illuminate the SLM 1140, which can include a polarization-based modulator that modulates the polarization of the light incident on the modulator, e.g., by selectively rotating the orientation of the modulator pixel-by-pixel depending on the pixel state. For example, a first pixel can be in a first state and rotate the polarization, while a second pixel can be in a second state and not rotate the polarization. The light between the coupling optics 1105 and the optics 1130 can illuminate the SLM 1140 rather uniformly. After being incident on the SLM 1140, the light is reflected back through the optics 1130. The optics 1130 can be configured to project the image from the SLM 1140 into the waveguide 1120 and ultimately into the eye 210 to make the image visible to the eye 210. In some designs, the retina of the eye 210 is the optical conjugate of the SLM 1140 and / or the image formed by the SLM 1140 and / or the image formed on the SLM 1140. The optical power of the optics 1130 helps project the image on the SLM 1140 into the eye 210 and onto the retina of the eye 210. In some embodiments, e.g., the optical power provided by the decoupling optical element 1180 can contribute to and / or affect the image ultimately formed in the eye 210. When the light reflected from the SLM 1140 travels through the optics towards the waveguide 1120, the optics 1130 acts as a projection lens. The optics can generally act as a Fourier transform of the image on the SLM 1140 to a plane in the waveguide 1120 adjacent to the coupling optical element 1160. The two lights propagating together through the optics 1130 (the first light from the light source 1110 to the SLM 1140, the second light from the SLM 1140 to the waveguide 1120) can generally act to image the pupil of the coupling optics 1105. The alignment and orientation of the light source 1110 (which may also be the coupling optics 1105 and / or the polarizer 1115), the optics 1130, and the SLM 1140 are such that the light from the light source 1110 reflected from the SLM 1140 is directed onto the coupling optical element 1160. The pupil associated with the coupling optics 1105 can be aligned with the coupling optical element 1160. The light can propagate through an analyzer 1150 (e.g., a polarizer) in the optical path between the SLM 1140 and the eye 210. As ​As shown, an analyzer (e.g., a polarizer) 1150 can be disposed on the optical path between the optical device 1130 and the optical coupling element 1160. The analyzer 1150 can be, for example, a linear polarizer with an orientation that transmits light of a first polarization (P polarization) and blocks light of a second polarization (S polarization), or transmits light of the second polarization and blocks light of the first polarization. The analyzer 1150 can be a clean-up polarizer and further block polarized light blocked by another polarizer between the SLM 1140 and the analyzer 1150 or within the SLM 1140. The analyzer 1150 can be, for example, a circular polarizer that acts as an isolator to mitigate reflections from the waveguide 1120, particularly the optical coupling element 1160, back towards the SLM 1140. As any of the polarizers disclosed herein, the analyzer 1150 can include a wire grid polarizer, such as an absorptive wire grid polarizer. Such a polarizer can provide significant absorption of unwanted light, thus increasing the contrast. Some such polarizers can include one or more dielectric layers on top of the wire and / or multilayer film. In some embodiments, the SLM 1140 can be a liquid crystal on silicon (LCOS) SLM and can include LC cells and retarders (e.g., compensators). In some embodiments, the analyzer 1150 can be a compensator designed to provide a more consistent polarization rotation (e.g., 90°) of the SLM 1140 for different angles of incidence and different wavelengths. The compensator can be used to improve the contrast of the display by improving the rotation polarization of light rays incident across the angle of incidence and wavelength range. The SLM 1140 can include, for example, a TN LCOS configured to rotate incident light of a first polarization (e.g., s polarization) of a first pixel to a second polarization (e.g., p polarization) so that when the light will propagate through the analyzer 1150, a bright pixel state is produced. Conversely, the SLM 1140 can be configured not to rotate incident light of a first polarization (e.g., s polarization) of a second pixel to a second polarization (e.g., p polarization) so that when the light will be attenuated or blocked by the analyzer 1150, the reflected light remains in the first polarization to produce a dark pixel. In this configuration, the orientation of the polarizer 1115 closer to the light source 1110 along the optical path can be different from (e.g., orthogonal to) the analyzer 1150 farther from the light source 1110 along the optical path. Other, for example, opposite, configurations are possible.

[0351] Then, the light is deflected, for example, turned by the optical coupling element 1160 to be guided in the waveguide 1120, where the light propagates by TIR. Then, the light impinges on the light distribution element 1170, which turns the light in another direction (e.g., more towards the z direction), causing an increase in the size of the eye movement range along the z-axis direction, as ​As shown. Thus, the light is deflected towards the output optical element 1180, which guides the light out of the waveguide 1120 towards the eye 210 (e.g., the user's eye as shown). The light output by different parts of the output optical element 1180 along the z direction increases the size of the eye movement range in at least a direction parallel to the z-axis, as ​ defined. It is noted that in this configuration, the optical device 1130 is used both to illuminate the SLM 1140 and to project an image onto the input optical element 1160. Thus, the optical device 1130 can be used as a projection optical device (e.g., uniformly) to distribute the light from the light source 1110, and as an imaging optical device to provide the image of the SLM 1140 and / or the image formed by the SLM 1140 into the eye. ​ / ​ The system 1100A in some cases can be more compact than ​ the system 1000. In some cases, not using the ​ PBS 1020 shown may reduce the cost of the system and / or reduce the size of the system. Additionally, in the absence of the PBS 1020, the system can be more symmetric and easier to design by shortening the back focal length of the optical device 1130.

[0352] As described above, alternative configurations are possible. Referring to ​ , for example, in some designs, the system 1100C can be configured to pass light with a polarization that is not rotated by the SLM 1140. In one embodiment, for example, the SLM 1140 is a liquid crystal (LC)-based SLM and can include vertically aligned (VA) LC on silicon (LCoS). The SLM 1140 can have a first pixel in a first state that does not rotate polarization and a second pixel in a second state that rotates polarization. In ​ the configuration shown, a single shared analyzer / polarizer 1155 is utilized. The analyzer 1155 can transmit light of a first polarization (e.g., s polarization) and attenuate or reduce the transmission of a second polarization (e.g., p polarization). Thus, light (e.g., s-polarized light) incident on the first pixel in the first state with a non-rotated polarization orientation is reflected by the SLM 1140 and propagates through the analyzer 1155 to the waveguide 1120. In contrast, light (e.g., s-polarized light) incident on the second pixel in the second state with a rotated polarization orientation is reflected by the SPM 1140 and is attenuated, reduced, or does not propagate through the analyzer 1155 to the waveguide 1120. This configuration can allow ​ the polarizer 1115 and the analyzer 1150 shown to be integrated into a shared optical element ( ​ the analyzer 1155 shown), thereby simplifying by reducing the number of optical components ​ / ​ System 1100. The analyzer 1155 can be disposed between the waveguide 1120 and the optical device 1130. In other embodiments, separate polarizer / analyzers and polarizer / analyzers can be used, such as ​ / ​ shown in system 1100. ​ and ​ shows a polarizer 1115 between the light source 1110 and the waveguide 1120, and an analyzer 1140 between the optical device 1130 and the waveguide 1120.

[0353] Various other configurations can be employed that utilize the optical device 1130 to both illuminate the SLM 1140 and image the image formed by the SLM 1140. For example, although ​ shows a single waveguide 1120, one or more waveguides can be used, such as a waveguide stack (potentially different waveguides for different colors of light). For example, ​ shows a cross-sectional side view of an example system 1200A that includes a stack 1205, where the stack 1205 includes waveguides 1120, 1122, 1124, each waveguide including an optical coupling element 1260, 1262, 1264. The waveguides 1120, 1122, 1124 can each be configured to output one or more different wavelengths of light, or one or more different wavelength ranges of light. The stack 1205 can be substantially similar to stacks 260 and 660( ​ and ​ ), and the waveguides 1120, 1122, 1124 of the shown stack 1205 can correspond to a portion of the waveguides 670, 680, 690, but the stack 1205 and the waveguides 1120, 1122, 1124 are not limited thereto. As ​ shown, the optical coupling elements 1260, 1262, 1264 can be associated with the waveguides 1120, 1122, 1124, respectively, including in or on the waveguides 1120, 1122, 1124. The optical coupling elements 1260, 1262, 1264 can be color selective and can primarily transfer or redirect certain wavelengths into the corresponding waveguides 1120, 1122, 1124 to guide those wavelengths therein. As shown, since the optical coupling elements 1260, 1262, 1264 are color selective, the optical coupling elements 1260, 1262, 1264 do not require lateral shifting and can be stacked on top of each other. Wavelength multiplexing can be employed to couple specific colors into the corresponding waveguides. For example, a red optical coupling element can couple red light into a waveguide designated for propagating red light without coupling blue or green light, and conversely, blue and green light are coupled into other waveguides by other blue or green selective waveguides, respectively.

[0354] In some embodiments, the light source 1110 can be a multi-color light source capable of emitting different colors of light at different times. For example, the light source 1110 can emit red, green, and blue (RGB) light and can be configured to emit red and no more than a negligible amount of green and blue during a first time period, green and no more than a negligible amount of red and blue during a second time period, and blue and no more than a negligible amount of red and green during a third time period. These cycles can be repeated, and the SLM 1140 can be coordinated to generate an appropriate pixel state pattern for a particular color (red, green, or blue) to provide an appropriate image color component for a given image frame. The different waveguides 1120, 1122, 1124 of the stack 1205 can each be configured to output light having different respective colors. For example, as ​ shown, the waveguides 1120, 1122, 1124 can be configured to output blue, green, and red light, respectively. Of course, other colors are possible. For example, the light source 1110 can emit other colors, and color-selective coupling-in optical elements 1260, 1262, 1264; coupling-out optical elements, etc. can be configured for these other colors. Additionally, the individual red, green, and blue emitters can be close enough to effectively act as a single pupil light source. The red, green, and blue emitters can be combined with lenses and dichroic beam splitters to form a single red, green, and blue pupil source. The multiplexing of a single pupil can extend beyond or be supplementary to color selectivity and can include the use of polarization-sensitive gratings and polarization switching. These color or polarization gratings can also be used in combination with multiple display pupils to increase the number of addressable layers.

[0355] The different coupling-in optical elements 1260, 1262, 1264 in the different waveguides 1120, 1122, 1124 can be arranged above and / or below each other and laterally aligned with respect to each other (e.g., along ​in the x and z directions shown), which is the opposite of being laterally shifted and misaligned relative to each other. Thus, in some embodiments, for example, different coupling optical elements 1260, 1262, 1264 can be configured such that light of a first color can be coupled into waveguide 1120 by coupling optical element 1260 and guided therein, light of a second color different from the first color can propagate through coupling optical element 1260 to the next coupling optical element 1262, and can be coupled into waveguide 1122 by coupling optical element 1262 and guided therein. Light of a third color different from the first and second colors can propagate through coupling optical elements 1260 and 1262 to coupling optical element 1264, and can be coupled into waveguide 1124 and guided therein. Additionally, coupling optical elements 1260, 1262, 1264 can be polarization selective. For example, different coupling optical elements 1260, 1262, 1264 can be configured such that light of a particular polarization is coupled into a waveguide by the corresponding polarization selective coupling optical elements 1260, 1262, 1264, or propagates through coupling optical elements 1260, 1262, 1264.

[0356] Depending on the configuration, SLM 1140 can include a polarization-based SLM that modulates polarization. System 1200A can include a polarizer and / or an analyzer to modulate the light injected into stack 1205 pixel by pixel, for example, depending on the state of each pixel (e.g., whether the pixel rotates the polarization orientation). Various aspects of such systems employing a polarization-based SLM have been discussed above, and any one of these features can be employed in combination with any other features described herein. However, other designs are still possible.

[0357] For example, a deflection-based SLM 1140 can be employed. For example, SLM 1140 can include one or more movable optical elements, such as movable mirrors, that can reflect and / or deflect light in different directions depending on the state of the optical element. SLM 1140 can, for example, include one or more pixels that include such optical elements as micromirrors or reflectors. SLM 1140 can, for example, integrate digital light processing (DLP TM ) technology using a digital micromirror device (DMD). ​An example of a system 1200B using such a deflection-based SLM 1140 is shown. System 1200B includes a deflection-based SLM 1140 and a light absorber 1250. The light absorber 1250 may include an absorbing material or structure configured to absorb light. The deflection-based SLM 1140 may include one or more micromovable mirrors that can be selectively tilted to deflect light in different directions. For example, the deflection-based SLM 1140 may be configured to deflect light from a light source 1110 incident thereon to coupling optical elements 1260, 1262, 1264 when a given pixel is in the bright state. As described above, thus, the light is thus coupled into one of the waveguides 1120, 1122, 1124 by one of the coupling optical elements 1260, 1262, 1264, for example depending on the color of the light, and is guided to the eye 210. In contrast, when a given pixel is in the dark state, the light from the light source 1110 may be deflected to the light absorber 1250, and the light is not coupled into one of the waveguides 1120, 1122, 1124 by one of the coupling optical elements 1260, 1262, 1264 and, is not guided to the eye 210. Instead, the light may be absorbed by the absorbing material including the light absorber 1250. In some embodiments, the polarizer 1150 may be a polarizer (e.g., a "clean-up" polarizer) that is used to eliminate unwanted reflections from the coupling optical elements 1260, 1262, 1264. The polarizer is useful because the optical device 1130 may include plastic optical elements having birefringence and capable of changing polarization. The "clean-up" polarizer may attenuate or remove light (e.g., reflections) having an unwanted polarization so that it is not guided onto the waveguides 1120, 1122, 1124. Other types of light conditioning elements may also be disposed between the SLM 1140 and the waveguides 1120, 1122, 1124, such as between the optical device 1130 and the waveguides 1120, 1122, 1124. For example, such a light conditioning element may also include a circular polarizer (i.e., a linear polarizer and a retarder such as a quarter-wave plate). The circular polarizer may reduce the amount of reflection from the waveguides 1120, 1122, 1124 or the coupling optical elements 1260, 1262, 1264 that is incident again on the waveguides 1120, 1122, 1124 and coupled into the waveguides 1120, 1122, 1124. The reflected light may be circularly polarized and may have a circular polarization opposite to that of the incident light (e.g., upon reflection, right-handed circularly polarized light is converted to left-handed circularly polarized light, or left-handed circularly polarized light is converted to right-handed circularly polarized light). The retarder in the circular polarizer may convert the circularly polarized light to linearly polarized light, such as orthogonally polarized light of a polarizer, which is attenuated (e.g., absorbed) by the linear polarizer in the circular polarizer. The clean-up polarizer may be used for polarization-independent modulators (such as DMDs).As described above, the cleaning polarizer can be used to suppress reflection and / or improve the coupling of light in an optimal polarization state into the light-coupling optical elements 1260, 1262, 1264.

[0358] ​ A side view or cross-sectional view of such a system 1200B is shown, while ​ A top view showing the lateral arrangement of the light-coupling optical element 1264, the light absorber 1250, and the light source 1110 is shown. Depending on the state of a particular pixel, the SLM 1140 is configured to reflect, deflect, and / or direct light from the light source 1110 to the lateral position of the light-coupling optical element 1264 (and other light-coupling optical elements 1260, 1262) or the light collector 1250.

[0359] In some designs, the light absorber 1250 may include an energy harvesting system. The light absorber 1250 may include, for example, a conversion element of light energy configured to convert light energy into electrical energy. The light energy conversion element may include, for example, a solar cell. The light energy conversion element may include, for example, a photodetector that generates an electrical output when light is incident thereon. The light energy conversion element may be electrically connected to an electrical component, such as a wire, to direct the electrical output to provide power to the system 1200B and / or possibly charge one or more batteries.

[0360] In some designs, a laterally shifted non-color-selective or broadband or multi-color light-coupling optical element may be used. For example, ​ is a perspective view of a system 1300 including a stack 1305 containing waveguides. The stack 1305 may be substantially similar to the stack 1205 of reference ​ Each waveguide in the stack 1305 may include light-coupling optical elements 1360, 1362, 1364. However, contrary to the design shown in ​ , the light-coupling optical elements 1360, 1362, 1364 are laterally shifted relative to each other. As shown in ​ , ​ and ​ , the light sources 1110, 1112, 1114 are also laterally shifted relative to each other and may be arranged to direct light to the respective light-coupling optical elements 1360, 1362, 1364 by passing the light through the optical device 1130, reflecting the light from the SLM 1140, and passing the reflected light through the optical device 1130 again. ​ The system 1300 of ​shown. The light sources 1110, 1112, 1114 may respectively correspond to the light-coupling optical elements 1360, 1362, 1364. In one design, for example, the light sources 1110, 1112, 1114 and the corresponding light-coupling optical elements 1360, 1362, 1364 are arranged symmetrically about the center of the optical device 1130 at approximately equal distances along a common (optical) axis. The common (optical) axis may intersect the center of the optical device 1130. In one design, for example, the light sources 1110, 1112, 1114 and the corresponding light-coupling optical elements 1360, 1362, 1364 are not arranged symmetrically about the center of the optical device 1130 at approximately equal distances along a common (optical) axis.

[0361] The light-coupling optical elements 1360, 1362, 1364 may be configured to couple light of multiple colors into their respective waveguides. Thus, these light-coupling optical elements 1360, 1362, 1364 may be referred to herein as broadband, multi-color, or non-color-selective light-coupling optical elements 1360, 1362, 1364. For example, in some cases, each of these light-coupling optical elements 1360, 1362, 1364 is configured to couple red, green, and blue light into the associated waveguide including the light-coupling optical elements 1360, 1362, 1364 such that this colored light is guided in the waveguide by TIR. Such broadband light-coupling optical elements 1360, 1362, 1364 may operate, for example, over a wide range of wavelengths, such as in the visible light range, or may select wavelengths or wavelength regions distributed, for example, across the visible light range. Thus, such broadband or multi-color or non-color-selective light-coupling optical elements 1360, 1362, 1364 may be configured to turn light of various different colors (such as red, green, and blue) into the waveguide to be guided within the waveguide by TIR. Although red, green, blue (RGB) is mentioned herein, for example, in connection with light sources, light-coupling optical elements, waveguides, etc., other colors or color systems may be additionally or alternatively used, such as including but not limited to magenta, cyan, yellow (CMY).

[0362] As ​ shown, the light sources 1110, 1112, 1114 are shown above the topmost waveguide and displaced relative to each other (e.g., in the x and z directions). Similarly, the three light-coupling optical elements 1360, 1362, 1364 are shown on three respective waveguides and displaced relative to each other (e.g., in the x, y, and z directions). ​ is ​Side view of the system 1300 shown, which shows the coupling optical elements 1360, 1362, 1364 that are laterally spatially shifted relative to each other (e.g., in the x and z directions) and some of the light sources 1110, 1112, 1114 that are laterally shifted relative to each other (e.g., in the x and z directions). ​ The optical device 1130 and the SLM 1140 are also shown.

[0363] ​ is ​ and ​ Top view of the augmented reality display system shown, which shows the coupling optical elements 1360, 1362, 1364 and the associated light sources 1110, 1112, 1114. In this design, the coupling optical elements 1360, 1362, 1364 and the associated light sources 1110, 1112, 1114 are arranged in an annular pattern around the center of the common (optical) axis. As shown, the light sources 1110, 1112, 1114 and the corresponding coupling optical elements 1360, 1362, 1364 are arranged approximately equidistantly around the center of the common (optical) axis, but this is not necessarily the case. In some designs, this center point can correspond to the center of the optical device 1130 along the common (optical) axis that intersects the center of the optical device 1130 and / or the position along the optical axis of the optical device 1130. Also accordingly, the non-color-selective coupling optical elements 1360, 1362, 1364 and the light sources 1110, 1112, 1114 are laterally shifted relative to each other (e.g., in the x and z directions).

[0364] Other lateral positioning arrangements are also possible. ​ An alternative configuration of the system 1400 is shown that includes a stack 1405 containing waveguides, where the coupling optical elements 1360, 1362, 1364 and the light sources 1110, 1112, 1114 are laterally shifted relative to each other. ​ is a side view, while ​ is ​ Top view of the system 1400 shown, ​ showing the laterally shifted coupling optical elements 1360, 1362, 1364 and the light sources 1110, 1112, 1114. ​ is ​ and ​ Orthogonal side views of the system 1400 shown.

[0365] ​ and ​The side view shows how the coupling optical elements 1360, 1362, 1364 are disposed on separate waveguides within the stack 1405 such that light can be coupled into the corresponding waveguides by the respective laterally displaced coupling optical elements 1360, 1362, 1364. In ​ and ​ , the coupling optical elements 1360, 1362, 1364 are shown disposed in the upper major surface of the waveguides. However, the coupling optical elements 1360, 1362, 1364 can alternatively be disposed on the lower major surface of the respective waveguides or within the body of the waveguides. Various configurations are possible.

[0366] As shown in the top view of ​ , the coupling optical elements 1360, 1362, 1364 are arranged in a column, laterally displaced relative to each other along the z - direction but not along the x - direction. Similarly, the light sources 1110, 1112, 1114 are arranged in a column, also laterally displaced relative to each other along the z - direction but not along the x - direction. The coupling optical elements 1360, 1362, 1364 are laterally displaced relative to the light sources 1110, 1112, 1114 along the x - direction.

[0367] Other configurations are also possible. ​ is a top view of the system 1500, which shows an alternative configuration of the light sources 1110, 1112, 1114 and the coupling optical elements 1360, 1362, 1364. Contrary to ​ where all the light sources 1110, 1112, 1114 are located substantially on one side (e.g., in a ring pattern) and all the coupling optical elements 1360, 1362, 1364 are located substantially on one side (i.e., the opposite side), the light sources 1110, 1112, 1114 and the coupling optical elements 1360, 1362, 1364 are scattered or alternated along the circumference of the ring pattern.

[0368] However, in some embodiments, the coupling optical elements 1360, 1362, 1364 and one or more associated light sources 1110, 1112, 1114 are also arranged in a ring pattern about a central point. Thus, the light sources 1110, 1112, 1114 and the corresponding coupling optical elements 1360, 1362, 1364 can be arranged to be substantially equidistant from the center. In some designs, this center can correspond to the center of the optical device 1130 along a common central axis intersecting the center of the optical device 1130 and / or a position along the optical axis of the optical device. Thus, light from the first light source 1110 can be coupled into the coupling optical element 1360 via the optical device 1130 across the center or central axis or optical axis of the optical device 1130 (as ​as shown in the top view). Similarly, light from the second light source 1112 can be coupled into the coupling optical element 1362 via the optical device 1130 across the center or central axis or optical axis of the optical device 1130. Similarly, light from the third light source 1114 can be coupled into the coupling optical element 1364 via the optical device 1130 across the center or central axis or optical axis of the optical device 1130. Also, accordingly, the non-color-selective coupling optical elements 1360, 1362, 1364 and the light sources 1110, 1112, 1114 are laterally displaced relative to each other (e.g., in the x and z directions). The optical device 1130 can be designed such that the focal point enters more into the stack 1405 so that the positions of the sub-pupil and the coupling optical elements 1360, 1362, 1364 are closer in the y direction. In this configuration, the coupling optical elements 1360, 1362, 1364 can be smaller because they are closer to the focal point of the optical device 1130. The light source 1110 can be located on the user side of the stack 1405 (e.g., similar to ​ and ​ ), thereby shortening the distance or optical path between the light source 1110 and the optical device 1130.

[0369] Such as ​ In the above various embodiments shown, stacks including a plurality of waveguides (e.g., stacks 1205, 1305, 1405, e.g., stack 1205 including waveguides 1120, 1122, 1124, stack 1305 including waveguides (not labeled), and stack 1405 including waveguides (not labeled)) can be included to process different colors (e.g., red, green, and blue). Different waveguides can be used for different colors. Similarly, a plurality of stacks can be included to provide different optical characteristics to the light coupled out from the respective stacks. For example, ​ The waveguides 1120, 1122, 1124 of the stack 1205 of ​ can be configured to output light having optical characteristics (e.g., providing a light power of a specific wavefront shape) that may be associated with the apparent depth of the light that appears to emit. For example, wavefronts with different amounts of divergence, convergence, or collimation can appear to be projected from different distances relative to the eye 210. Therefore, a plurality of stacks can be included in different stacks, and these different stacks are configured such that the light coupled out by the coupling optical element has different amounts of convergence, divergence, or collimation, and thus appears to originate from different depths. In some designs, different stacks can include different lenses, such as diffractive lenses or other diffractive optical elements, to provide different amounts of light power to different stacks. Therefore, different stacks will produce different amounts of convergence, divergence, or collimation, and thus, the light from different stacks will appear to be associated with different depth planes or objects at different distances relative to the eye 210.

[0370] ​is a side view of system 1600 including stacks 1605, 1610, 1620. As ​ shown, system 1600 includes three stacks 1605, 1610, 1620, but this is not necessarily the case. Systems with fewer or more stacks can be envisioned. Each of stacks 1605, 1610, and 1620 includes one or more (e.g., three) waveguides. ​ Also shown are coupled-in optical element sets 1630, 1640, 1650. The first set 1630 is associated with the first stack 1605, the second set 1640 is associated with the second stack 1610, and the third set 1650 is associated with the third stack 1620. Sets 1630, 1640, 1650 are laterally displaced relative to each other. Sets 1630, 1640, 1650 each include color-selective coupled-in optical elements that are configured to couple in different respective colors, substantially similar to ​ the coupled-in optical elements 1260, 1262, 1264 of ​ As shown, the coupled-in optical elements within each of sets 1630, 1640, 1650 are not laterally displaced relative to each other, but this is not necessarily the case. Systems can be envisioned in which the coupled-in optical elements within a set are laterally displaced relative to each other. System 1600 can be configured such that the light coupled out from each of stacks 1605, 1610, 1620 has a different optical power. For example, the waveguides in a stack can include an out-coupling optical element or diffractive lens having a given optical power. The optical powers of different stacks 1605, 1610, 1615 can be different such that the light from one stack appears to originate from a different depth than the light from another stack. For example, the optical power of one stack can cause the light from that stack to be collimated, while the optical power of another stack can cause the light from that stack to diverge. The diverging light can appear to originate from an object in close proximity to the eye 210, while the collimated light can appear to come from an object at a far distance. Thus, the light coupled out from the first stack 1605, the second stack 1610, and the third stack 1620 can have at least one of different amounts of convergence, divergence, and collimation, and thus appear to originate from different depths. In some embodiments, the light coupled out from one of the stacks can be collimated, while the light coupled out by a different stack can diverge. The light coupled out from one of the other stacks may also diverge, but by a different amount.

[0371] As ​As shown, the light source 1110 can be arranged relative to the optical device 1130 and the SLM 1140 to direct light into the coupled-in optical element group 1630, the light source 1112 can be arranged relative to the optical device 1130 and the SLM 1140 to direct light into the coupled-in optical element group 1640, and the light source 1114 can be arranged relative to the optical device 1130 and the SLM 1140 to direct light into the coupled-in optical element group 1650. The light sources 1110, 1112, 1114 can be configured to emit light of different colors at different times. Similarly, since the color-selective coupled-in optical elements are arranged in the above manner, light of different colors can be coupled into different waveguides in the stack. For example, if blue light is emitted from the second light source 1112, the optical device 1130 and the SLM 1140 will direct the blue light to the second coupled-in optical element group 1640. The light can propagate through the first red coupled-in optical element and the second green coupled-in optical element in the second group 1640 and be redirected by the third blue coupled-in optical element in the second group 1640 into the third waveguide in the second stack 1610. The waveguides in the second stack 1610 can include an outcoupling optical element or other optical elements (such as a diffractive lens) having a focal power to provide a light beam to the eye 210 associated with a specific depth plane or an object distance associated with the second stack 1610.

[0372] ​ is ​ A top view of the system 1600 in FIG. The different coupled-in optical element groups 1630, 1640, 1650 are shown to be laterally displaced relative to each other (e.g., in the x direction). Similarly, the light sources 1110, 1112, 1114 are shown to be laterally displaced relative to each other (e.g., in the x direction).

[0373] Various different variations of the above system are possible. For example, the position of the light source 1110 relative to one or more waveguides and the optical device 1130 can be different. For example, ​ is a side view of the system 1700, and the position of the light source 1110 of the system 1700 relative to the waveguide 1720 and the optical device 1130 is different from that shown in FIGS. 11 to ​ shown. Additionally, ​Shows a design of a waveguide 1720 that is divided into a first portion 1720a and a second portion 1720b. The waveguide 1720 may further include a reflector 1730 configured to couple out light guided in the first portion 1720a adjacent to the light source 1110 from the first portion 1720a and couple it into the optical device 1130 towards the SLM 1140. Additionally or alternatively, the system 1700 may include a diffractive coupling-out optical element to couple out light in the first portion 1720a of the waveguide 1720 and couple it into the optical device 1130 towards the SLM 1140. The reflector 1730 may be opaque and include an isolator that reduces crosstalk between the first portion 1720a and the second portion 1720b. The waveguide 1720 has a first side 1721 and a second side 1723 opposite the first side 1721, and the optical device 1130 and the SLM 1140 are disposed on the first side 1721 such that light from the SLM 1140 is guided onto the first side 1721. In this example, the light source 1110 is disposed on the first side 1721 of the waveguide 1720 such that light from the light source 1110 is incident on the first side 1721 before propagating through the optical device 1130 to reach the SLM 1140. The system 1700 may further include a coupling-in optical element 1710 that is disposed on or in the first portion 1720a. The coupling-in optical element 1710 may be configured to receive light from the light source 1110 and couple the light into the first portion 1720a. The coupling-in optical element 1710 may include a diffractive optical element or a reflector configured to turn light incident thereon at an angle into the first portion 1720a to guide the light in the first portion 1720a by TIR.

[0374] The reflector 1730 may be configured to direct light guided in the first portion 1720a out of the first portion 1720a and toward the optical device 1130 and the SLM 1140. (As described above, in some embodiments, a diffractive optical element may additionally or alternatively be used to direct light in the first portion 1720a out of the first portion 1720a and toward the optical device 1130 and the SLM 1140). Thus, the reflector 1730 may be a mirror, a reflective grating, one or more coatings that reflect light of the waveguide 1720 toward the SLM 1140. The light emitted from the first portion 1720a by the reflector 1730 propagates through the optical device 1130, is incident on the SLM 1140, and then propagates through the optical device 1130 again and is incident on the second portion 1720b. As described above, the light reflected from the SLM 1140 and transmitted through the optical device 1130 may be incident on the optical coupling element 1160, and then the light is redirected to be guided in the second portion 1720b. The light guided in the second portion 1720b may be coupled out of the second portion 1720b by an optical coupling-out element 1180 (not shown) and guided to the eye 210.

[0375] As described above, the reflector 1730 may be an isolator that reduces crosstalk between the first portion 1720a and the second portion 1720b. The reflector 1730 may include an opaque surface and / or a reflective surface. The reflector 1730 may be disposed within the waveguide 1720 and, in some cases, may define one side of the first portion 1720a and the second portion 1720b.

[0376] Separate waveguides may be used instead of the first portion 1720a and the second portion 1720b having the waveguide 1720. ​is a side view of system 1800, which includes a first waveguide 1822 that is configured to receive light from a light source 1110 and direct the light guided therein to an optical device 1130 and towards an SLM 1140. The system 1800 additionally includes a second waveguide 1820 that receives the light after the light from the SLM 1140 propagates through the optical device 1130 again. The first waveguide 1822 includes an input optical element 1730a and an output optical element 1730b, respectively. These input optical element 1730a and output optical element 1730b may include a reflective surface that is oriented to couple light into and out of the waveguide 1822. The input optical element 1730a may include, for example, a reflective surface that is arranged to receive light from the light source 1110 and is oriented (e.g., tilted) at an angle to direct the light into the waveguide 1822 so as to guide the light in the waveguide 1822 by TIR. The output optical element 1730b may include, for example, a reflective surface that is oriented (e.g., tilted) at an angle to direct the light guided within the waveguide 1822 such that the light is emitted from the waveguide 1822. The output optical element 1730b may be positioned such that the light diverted from the waveguide 1822 is directed into the optical device 1130, reflected by the SLM 1140, propagates through the optical device 1130 again, and impinges on the input optical element 1730c of the second waveguide 1820.

[0377] The input optical element 1730c in the second waveguide 1820 may include a reflective surface that may be positioned and oriented (e.g., tilted) to receive the light incident thereon from the SLM 1140 and redirect the light incident thereon from the SLM 1140 so as to guide the light in the second waveguide 1820 by TIR. ​ The optical device 1130 and the light source 1110 are shown disposed on the same side of the waveguides 1820, 1822. The system 1800 may further include an isolator that reduces crosstalk between the waveguide 1822 and the waveguide 1820. The isolator may include an opaque surface and / or a reflective surface. The isolator may be disposed on at least one of or on at least one of the waveguides 1820, 1822.

[0378] Various designs such as those discussed above may include other features or components. ​For example, a side view of system 1900 is shown, which includes variable-focus optical elements (or adaptive optical elements) 1910, 1920. The variable-focus optical elements 1910, 1920 may include optical elements configured to provide variable optical power by changing. The variable-focus optical elements 1910, 1920 may include multiple states, such as a first state and a second state, where in the first state, the variable-focus optical elements 1910, 1920 have an optical power different from that in the second state. For example, the variable-focus optical elements 1910, 1920 may have a negative optical power in the first state and zero optical power in the second state. In some embodiments, the variable-focus optical elements 1910, 1920 have a positive optical power in the first state and zero optical power in the second state. In some embodiments, the variable-focus optical elements 1910, 1920 have a first negative optical power or a first positive optical power in the first state and a different second negative optical power or a second positive optical power in the second state. Some adaptive optical elements or variable-focus optical elements 1910, 1920 may have more than two states and may provide a continuous optical power distribution.

[0379] The variable-focus optical elements 1910, 1920 may include lenses (such as variable lenses) and are transmissive. ​Shown are transmissive or transparent adaptive optical elements or variable focal length optical elements 1910, 1920. The variable focal length optical elements 1910, 1920 may include liquid lenses (such as movable membranes and / or electro-wetting). The variable focal length lenses may also include liquid crystal lenses, such as switchable liquid crystal lenses, such as switchable liquid crystal polarization lenses, which may include diffractive lenses for example. Alvarez lenses may also be used. Other types of variable focal length optical elements 1910, 1920 may be employed. Examples of variable focal length optical elements may be found in the U.S. application Ser. No. 62 / 518,539, filed Jun. 12, 2017, entitled “AUGMENTED REALITY DISPLY HAVING MULTI-ELEMENT ADAPTIVE LENS FOR CHANGING DEPTH PLANES”, the entire content of which is hereby incorporated by reference. The variable focal length optical elements 1910, 1920 may have electrical inputs that receive electrical signals that control the amount of optical power exhibited by the variable focal length optical elements 1910, 1920. The variable focal length optical elements 1910, 1920 may have positive optical power and / or negative optical power. In addition to variable focal length elements (such as polarization switches, geometric phase (GP) lenses, fluid lenses, etc.), the variable focal length elements 1910, 1920 may also include fixed lenses (such as diffractive lenses, refractive lenses, etc.) to generate desired depth planes in the light field.

[0380] The first variable focal length optical element 1910 may be disposed between the stack 1905 and the eye 210. The stack 1905 may include the different waveguides for different colors described above. The first variable optical element 1910 may be configured to introduce different amounts of optical power, negative optical power and / or positive optical power. The variable optical power may be used to change the divergence and / or collimation of the light coupled out of the stack 1905 to change the depth at which the virtual objects projected into the eye 210 by the system 1900 appear to be located. Thus, a four-dimensional (4D) light field may be formed.

[0381] The second variable focal length optical element 1920 is located on the side of the stack 1905 opposite the first variable focal length optical element 1920. The second variable focal length optical element 1920 may thus compensate for the effect of the first optical element 1910 on the light received from the system 1900 and the world 510 in front of the eye 210. Thus, the world view may actually be unchanged or changed as needed.

[0382] System 1900 may further include a static or variable prescription or corrective lens 1930. Such a lens 1930 may provide refractive correction for the eye 210. Additionally, if the prescription lens 1930 is a variable lens, it may provide different refractive corrections for multiple users. Variable focus lenses were discussed above. The eye 210 may, for example, have myopia, hyperopia, and / or astigmatism. The lens 1930 may have a prescription (e.g., optical power) that reduces the refractive error of the eye 210. The lens 1930 may be spherical and / or cylindrical and may be positive or negative. The lens 1930 may be disposed between the stack 1905 and the eye 210 such that light from the world 510 and from the stack 1905 passes through the correction provided by the lens 1930. In some embodiments, the lens 1930 may be disposed between the eye 210 and the first variable focus optical element 1910. Other positions of the lens 1930 are possible. In some embodiments, the prescription lens may be variable and allow for multiple user prescriptions to be achieved.

[0383] In some designs, the system 1900 may include an adjustable dimming device 1940. In some embodiments, the adjustable dimming device 1940 may be disposed on a side of the waveguide stack 1900 opposite the eye 210 (e.g., the world side). Thus, the adjustable dimming device 1940 may be disposed between the waveguide stack 1900 and the world 510. The adjustable dimming device 1940 may include an optical element that provides variable attenuation of light passing therethrough. The adjustable dimming device 1940 may include an electrical input to control the attenuation level. In some cases, the adjustable dimming device 1940 is configured to increase the attenuation when the eye 210 is exposed to bright light, such as when the user goes outdoors. Thus, the system 1900 may include a light sensor to sense the brightness of the ambient light and control electronics to drive the adjustable dimming device 1940 to change the attenuation based on the light intensity sensed by the light sensor.

[0384] Different types of adjustable dimmers 1940 can be employed. Such adjustable dimmers 1940 can include variable liquid crystal switches having polarizers, electrochromic materials, photochromic materials, etc. The adjustable dimmer 1940 can be configured to adjust the amount of light entering and / or transmitted through the stack 1905 from the world 510. The adjustable dimmer 1940 can be used in some cases to reduce the amount of light from the surrounding environment that propagates through the waveguide stack 1900 to reach the eye 210, which otherwise provides glare and reduces the user's ability to perceive virtual objects / images injected into the eye 210 from the stack 1905. Such adjustable dimmers 1940 can reduce incident bright ambient light so as not to wash out the images projected into the eye 210. Thus, the contrast of the virtual objects / images presented to the eye 210 can be increased by virtue of the adjustable dimmer 1940. Conversely, if the ambient light is low, the adjustable dimmer 1940 can be adjusted to reduce the attenuation so that the eye 210 can more easily see the objects in the world 510 in front of the user. Dimming or attenuation can be performed across the system or be localized to one or more parts of the system. For example, multiple localized parts can be dimmed or set to attenuate the light from the world 510 in front of the user 210. These localized parts can be separated from each other by parts without such increased brightness adjustment or attenuation. In some cases, only a portion is dimmed or caused to provide increased attenuation relative to other parts of the eyepiece. Other components can be added in different designs. The arrangement of the components can also be different. Similarly, one or more components in the system can be excluded.

[0385] ​ An example of another configuration is shown. ​Shows a side view of system 2000, which includes laterally shifted optical coupling elements 1360, 1362, 1364 on different waveguides, and a color filter array 2030, which includes laterally shifted color filters 2040, 2042, 2044 aligned with respective optical coupling elements 1360, 1362, 1364. The color filter array 2030 can be disposed on one side of stack 2005 adjacent to eye 210 and optical device 1130. The color filter array 2030 can be located between stack 2005 and optical device 1130. The color filter array 2030 can be disposed in cover glass 2050 located between stack 2005 and optical device 1130 or on cover glass 2050 located between stack 2005 and optical device 1130. The color filter array 2030 can include one or more different color filters 2040, 2042, 2044 that are laterally shifted relative to each other, such as a red color filter, a green color filter, and a blue color filter. System 2000 includes light sources 1110, 1112, 1114 that are laterally shifted relative to each other. These light sources 1110, 1112, 1114 can include light sources of different colors, such as red, green, and blue light sources. The color filters 2040, 2042, 2044 can be transmissive or transparent color filters. In some embodiments, the color filters 2040, 2042, 2044 include absorption color filters; however, the color filters 2040, 2042, 2044 can also include reflective color filters. The color filters 2040, 2042, 2044 in the color filter array 2030 can be separated and / or surrounded by a mask, such as an opaque mask that would reduce stray light propagation. The color filters in the color filter array 2030 can be used to reduce or eliminate unwanted reflections within the system, such as unwanted reflections from waveguides and / or optical coupling elements 1360, 1362, 1364, preventing these unwanted reflections from re-entering the waveguides for different colors through the optical coupling elements 1360, 1362, 1364 for different colors. Examples of color filter arrays can be found in U.S. application Ser. No. 15 / 683412, filed Aug. 22, 2017, entitled "PROJECTOR ARCHITECTURE INCORPORATING ARTIFACT MITIGATION", the entire content of which is hereby incorporated by reference; and in U.S. application Ser. No. 62 / 592607, filed Nov. 30, 2017, entitled "PROJECTOR ARCHITECTURE INCORPORATING ARTIFACT MITIGATION", the entire content of which is hereby incorporated by reference.The mask can be a black mask and can include an absorbing material to reduce the propagation and reflection of stray light. The light sources 1110, 1112, 1114 can be arranged relative to the optical device 1130 and the SLM 1140 to couple light into the corresponding color filters 2040, 2042, 2044 in the color filter array 2030. For example, the color filter array 2030 can include first, second, and third (e.g., red, green, and blue) color filters 2040, 2042, 2044 that are arranged to receive light from the first, second, and third light sources 1110, 1112, 1114, respectively. The first, second, and third (e.g., red, green, and blue) color filters 2040, 2042, 2044 can be aligned (e.g., along the x and z directions) with respective light-coupling elements 1360, 1362, 1364. Thus, the light from the first light source 1110 will be guided through the first color filter 2040 and reach the first light-coupling element 1360, the light from the second light source 1112 will be guided through the second color filter 2042 and reach the second light-coupling element 1362, and the light from the third light source 1114 will be guided through the third color filter 2044 and reach the third light-coupling element 1364. In some embodiments, the light-coupling elements 1360, 1362, 1364 can be color-specific. For example, the first light-coupling element 1360 and the second light-coupling element 1362 can be configured to couple light of respective first and second colors into the first and second waveguides, respectively. Similarly, the first light-coupling element 1360, the second light-coupling element 1362, and the third light-coupling element 1364 can be configured to couple light of respective first, second, and third colors into the first, second, and third waveguides, respectively. The first light-coupling element 1360 can be configured to couple more light of the first color into the first waveguide than the second color (or the third color). The second light-coupling element 1362 can be configured to couple more light of the second color into the second waveguide than the first color (or the third color). The third light-coupling element 1364 can be configured to couple more light of the third color into the second waveguide than the first color or the second color. In other configurations, the light-coupling elements 1360, 1362, 1364 can be broadband. For example, the first light-coupling element 1360 can be configured to couple light of the first, second, and third colors into the first waveguide. The second light-coupling element 1362 can be configured to couple light of the first, second, and third colors into the second waveguide. The third light-coupling element 1364 can be configured to couple light of the first, second, and third colors into the third waveguide. However, the plurality of color filters 2040, 2042, 2044 can be color-specific, selectively transmitting light having a specific color. For example, the first color filter 2040 can transmit more of the first color than the second color (and the third color).The second color filter 2042 may transmit more of the second color than the first color (and the third color). The third color filter 2044 may transmit more of the third color than the first and second colors. Similarly, the first color filter 2040, the second color filter 2042, and the third color filter 2044 may be color filters that selectively transmit the first color, the second color, and the third color, respectively. Thus, the first color filter 2040, the second color filter 2042, and the third color filter 2044 may be bandpass filters that selectively pass the first color, the second color, and the third color, respectively. In some embodiments, the first light source 1110, the second light source 1112, and the third light source 1114 may selectively emit the first color, the second color, and the third color, respectively. For example, the first light source 1110 may emit more of the first color than the second color (and the third color). The second light source 2042 may emit more of the second color than the first color (and the third color). The third light source 2044 may emit more of the third color than the first and second colors. The color filters 2040, 2042, 2044 may reduce the amount of stray light inadvertently directed to a particular coupled-in optical element. In other embodiments, one or more of the light sources 1110, 1112, 1114 are broadband light sources. For example, the first light source 1110 may emit the first color and the second color (and possibly the third color). The second light source 1112 may also emit the first and second colors and the second color (and possibly the third color). The third light source 1114 may also emit the color and the second color (and possibly the third color). Although in... ​ Three color filters are shown, but more or fewer color filters may also be included. For example, in some embodiments, two color filters (instead of three) may be used. Thus, two colors corresponding to the two color filters may be selectively transmitted by the color filters. In some such embodiments, two corresponding coupled-in optical elements may be used and aligned with the two color filters. In some embodiments, the two coupled-in optical elements selectively couple the two colors into two respective waveguides. In some embodiments, two light sources may be used instead of three. Variations of other components and other numbers of components may be used. Additionally, the color filters 204, 2042, 2044 may or may not be integrated in a single array.

[0386] As described above, the components and their locations and arrangements may vary. For example, although... ​ a polarizer 1150 is shown disposed between the optical device 1130 and the stack 1905, the polarizer 1150 may be located at a different position. ​Shows an analyzer 1150 located between the optical device 1130 and the SLM 1140. In some designs, the analyzer (e.g., polarizer) 1150 can be directly attached to the SLM 1140. For example, the analyzer 1150 can be glued or mechanically coupled to the SLM 1140. For example, the analyzer 1150 can be glued, adhered to the SLM 1140 (e.g., to the SLM window) using an adhesive. Thus, although ​ shows a gap between the analyzer 1150 and the SLM 1140, in some designs, there is no gap between the analyzer 1150 and the SLM 1140. The analyzer 1150 can be mechanically adhered to the SLM 1140 (e.g., using mechanical fixtures), and in this case, a gap may or may not be included between the analyzer 1150 and the SLM 1140. The birefringence from the optical device 1130 can be removed by directly positioning the polarizer on the SLM 1140 as described above. In some embodiments, an analyzer 1150 can also be included between the optical device 1130 and the coupled optical elements 1360, 1362, 1364 to clean up the polarization of the light exiting the optical device 1130 (e.g., as ​ shown by the dashed line in). Additionally, adjacent to the SLM 1140, e.g., between the optical device 1130 and the SLM 1140, a retarder (not shown) such as a quarter-wave plate can be included. As used herein, a quarter-wave plate can refer to a quarter-wavelength retarder, regardless of whether the quarter-wavelength retarder includes a plate, film, or other structure for providing a quarter-wavelength delay. In ​ , for example, a retarder (e.g., a quarter-wave plate) can be disposed between the analyzer 1150 and the SLM 1140. The retarder (e.g., a quarter-wave plate) can be used for skew ray management. For example, the retarder (e.g., a quarter-wave plate) can, for example, compensate for variations caused by wavelength differences and differences in the incident angle on the SLM 1140. As described above, a compensator can be included, and the compensator can provide a more consistent polarization rotation (e.g., 90 degrees) of the SLM 1140 for different incident angles and different wavelengths. The compensator can be used to increase the contrast of the display by providing a more consistent orthogonal rotation. As described above, the compensator can be attached or adhered to the SLM 1140. For example, glue, cement, or other adhesives can be used. The compensator can also be attached to the SLM 1140 using mechanical fixtures. A gap may or may not be included between the compensator and the SLM 1140. Additionally or alternatively, other adjustment optical devices can also be included and adhered to the SLM 1140 as described above with respect to the analyzer 1150 and / or the compensator.

[0387] In some embodiments, a large angular spread (e.g., ~70 degrees) can be used. The angular spread can refer to, for example, the angle of light entering the optical device 1130 from the light sources 1110, 1112, 1114, and / or the angle of light leaving the optical device 1130 and entering the optically coupled elements 1360, 1362, 1364. In these embodiments, a thinner SLM 1140 can be used. For example, if the SLM 1140 is a liquid crystal (LC) SLM (e.g., a liquid crystal on silicon (LCOS) SLM), the LC layer can be made thinner to accommodate the large angular spread.

[0388] The second-pass retardance through the polarizer and analyzer 1150 may need to be a half-wavelength. The polarizer can be located between the optical device 1130 and the analyzer 1150. The second-pass retardance can be a function of the ratio of the refractive index of the LCOS SLM 1140 to the thickness of the LCOS SLM 1140. For a given refractive index of the LCOS SLM 1140 and a given thickness of the LCOS SLM 1140, the optical path length for light entering and leaving the LCOS SLM 1140 at large angles is greater than that for light entering and leaving the LCOS SLM 1140 at small angles. The optical path length is related to the thickness of the LCOS SLM 1140. In one example, the LCOS SLM can have a first refractive index and a first thickness. For small angles, the second-pass retardance of the LCOS SLM with the first refractive index and the first thickness can be a half-wavelength. For large angles, the second-pass retardance of the LCOS SLM with the first refractive index and the first thickness may not be a half-wavelength (e.g., it can be greater than a half-wavelength). The thickness of the LCOS SLM can be changed from the first thickness to a second thickness, where the second thickness is less than the first thickness. For small angles, the second-pass retardance of the LCOS SLM with the first refractive index and the second thickness may not be a half-wavelength (e.g., it can be less than a half-wavelength). For large angles, the second-pass retardance of the LCOS SLM with the first refractive index and the second thickness can be a half-wavelength.

[0389] In addition, although ​ and 20B the use of the polarization-based SLM 1140 is shown, other types of SLMs can also be utilized. For example, ​ the use of a deflection-based SLM 1140, such as an SLM based on movable micromirrors, is shown. As described above, such an SLM 1140 can include digital light processing (DLP TM s) and digital micromirror device (DMD) technology. As described above, the deflection-based SLM 1140 can couple light from one of the light sources 1110, 1112, 1114 into the corresponding light-coupling optical elements 1360, 1362, 1364, depending on the state of the pixels of the SLM 1140. In one state, the light from the light sources 1110, 1112, 1114 will be directed to the corresponding light-coupling optical elements 1360, 1362, 1364, as ​ shown. In another state, the light from the light sources 1110, 1112, 1114 will be directed away from the light-coupling optical elements 1360, 1362, 1364, as ​ shown. In some embodiments, when in the off state, the black absorption mask between the color filters 2040, 2042, 2044 in the color filter array 2030 can be used as a light absorber. As described above, the color filters 2040, 2042, 2044 can be surrounded and / or separated by masks such as absorption masks (e.g., black masks). The mask can include an absorbing material such that more incident light is absorbed than reflected from it. The mask can also be opaque.

[0390] Other variations are possible. Although the light sources are shown as emitters 1110, 1112, 1114 (e.g., LEDs, laser diodes) coupled to coupling optical devices 1105 such as non-imaging optical coupling elements (e.g., compound parabolic concentrators (CPCs) or cones), other configurations are possible. For example, the coupling optical device 1105 (e.g., CPC) can be tilted relative to the waveguide stack. In some cases, the projector (i.e., the optical device 1130 and the SLM 1140) can be tilted relative to the eyepiece (e.g., the waveguide stack). In some embodiments, the lens optical device 1130 is tilted relative to the SLM 1140 to reduce distortion, such as trapezoidal distortion. A Scheimplug configuration can be employed to reduce such distortion. Components can be tilted as needed (e.g., the optical device 1130 and / or the spatial light modulator 1140), for example, to more conformally fit to the head and / or face. As described above, one or more light emitters and / or coupling optical devices 1105 can be tilted. In some configurations, the assembly including the waveguide can be tilted such that the side closer to the eye 210 side (e.g., the temporal side) is closer to the eye 210 to increase the perceived field of view of the entire binocular system (at the expense of binocular overlap).

[0391] As described above, the components and their positions and arrangements can vary. For example, ​is a side view of system 2000F, which includes a cover glass 2050 disposed between a stack 2005 and an optical device 1130. In some designs, light sources 1110, 1112, 1114 may be disposed on the world side of the cover glass 2050 and configured to cause light to propagate through the cover glass 2050 to the optical device 1130 and the SLM 1140. As shown, the cover glass 2050 may extend laterally (e.g., parallel to the x-axis) beyond the stack 2005 such that light emitted by the light sources 1110, 1112, 1114 enters the optical device 1130 without propagating through waveguides in the stack 2005. Although system 2000F shows a deflection-based SLM 1140, a similar light source configuration may also be used for non-deflection-based SLMs or any other configuration or feature disclosed herein.

[0392] ​ is a side view of system 2000G, which includes a cover glass 2060 disposed on the world side of the stack 2005 (i.e., opposite the side of the stack 2005 adjacent to the optical device 1130). In some designs, light sources 1110, 1112, 1114 may be disposed on the world side of the cover glass 2050 and configured to cause light to propagate through the cover glass 2050 to the optical device 1130 and the SLM 1140. As shown, the cover glass 2060 may extend laterally (e.g., parallel to the x-axis) beyond the stack 2005 such that light emitted by the light sources 1110, 1112, 1114 enters the optical device 1130 without propagating through waveguides in the stack 2005. Although system 2000G shows a deflection-based SLM 1140, a similar light source configuration may also be used for non-deflection-based SLMs or any other configuration or feature disclosed herein.

[0393] In addition, as described above, configurations that facilitate light recycling may be employed. For example, ​Is a partial side view of system 2100, which is equipped with a configuration for performing light recycling on light from light source 1110. The light source 1110 can be arranged relative to a polarizer 1115, which is configured to recycle light with an undesired polarization. The polarizer 1115 can include, for example, a wire grid polarizer that transmits light of a first polarization and retroreflects light of a second, opposite polarization. Thus, light 2110 can be emitted from the light source 1110 and impinge on the polarizer 1115. The polarizer 1115 can transmit light of the first polarization, and a projector (not shown) is configured for use therewith. For example, an SLM can properly process the light of the first polarization. Light 2120 of the second polarization is reflected back toward the light source 1110 and can be recycled. After being reflected from a portion (e.g., sidewall) of a coupling optical device (not shown), such as a compound parabolic concentrator (CPC) or other non-imaging optical device, at various angles, the polarization of light 2120 can be changed to rotate the polarization. Some light with a suitable polarization (e.g., polarization orientation) that can be passed by the polarizer 1115 can be generated. Multiple reflections can change the polarization of the light and can cause the light to exit with a desired polarization. Then, the recycled light 2130 is emitted back toward the polarizer 1115. As more and more desired polarization is generated, this configuration can improve efficiency, such as energy efficiency. Additionally or alternatively, a retarder can be used to change the polarization state of the reflected light and reuse the light.

[0394] ​Another configuration is shown that includes light sources 1110, 1112, 1114 and corresponding condenser optics 2210, 2212, 2214. The condenser optics 2210, 2212, 2214 can include lenses or other optics to collect light from the light sources 1110, 1112, 1114. The light sources 1110, 1112, 1114 can be laser diodes or other emitters that emit light over a wide range of angles. The condenser optics 2210, 2212, 2214 can be used to collect most of the light. The light sources 1110, 1112, 1114 can emit light asymmetrically. For example, light can be emitted over a greater range of angles in a direction (e.g., the x or z direction) other than an orthogonal direction (e.g., the z or x direction). Thus, the condenser optics 2210, 2212, 2214 can be asymmetric. For example, the condenser optics 2210, 2212, 2214 can have different optical powers in different possible orthogonal directions. The condenser optics 2210, 2212, 2214 can include, for example, lenses such as anamorphic lenses. The condenser optics 2210, 2212, 2214 can also include non-imaging optics. Apertures 2220, 2222, 2224 can be included. For example, when the light sources 1110, 1112, 1114 are lasers such as laser diodes, diffusers 2230 can also be included near the apertures 2220, 2222, 2224. In the case where the diffuser is adjacent to the apertures 2220, 2222, 2224, the apertures appear to be located at the position of the laterally displaced light source. The apertures 2220, 2222, 2224 can be matched to the coupling optical elements on one or more waveguides via the above-described optics and the SLM. For example, each aperture 2220, 2222, 2224 can be matched to a corresponding coupling optical element. Similarly, in some embodiments, such as ​ as shown, each aperture 2220, 2222, 2224 can be matched to a corresponding set of coupling optical elements (e.g., having color selectivity).

[0395] A variety of system variations and configurations are possible. For example, although linearly polarized light has been described as propagating through optical device 1130 to SLM 1140 and then propagating back through the optical device to the waveguide stack, in some designs, circularly polarized light may alternatively be used. For example, circularly polarized light can be directed into optical device 1130. A retarder such as a quarter-wave plate can be set such that the light propagates through the retarder before being incident on the SLM. The retarder (e.g., quarter-wave plate) can be set between optical device 1130 and SLM 1140. In some cases, as described above, the retarder (e.g., quarter-wave plate) can be adhered to SLM 1140, for example, using an adhesive or a mechanical fixing device. The retarder (e.g., quarter-wave plate) can transform the linearly polarized light after reflection from SLM 1140 into circularly polarized light. Thus, in some embodiments, the circularly polarized light can propagate back towards the stack through optical device 1130 again. For example, another retarder (e.g., quarter-wave plate) adjacent to polarizer 1150 can transform the circularly polarized light into linearly polarized light, which can pass through or not pass through the polarizer depending on the linear polarization (e.g., orientation). The pixels of SLM 1140 can have states that can vary to rotate or not rotate the polarization. Other configurations are also possible.

[0396] ​is a side view of an augmented reality display system 2300 that includes a light source 2305, a polarization rotator 2307, an optical device (such as a lens) 2320 having a focal power, polarizers 2312, 2335 such as linear polarizers (e.g., horizontal or vertical polarizers), retarders 2315, 2330, 2340 such as quarter-wave retarders (e.g., quarter-wave plates), and at least one waveguide 2348 for outputting image information to a user. Such a configuration can be used to illuminate a reflective spatial light modulator (not shown) such that light emitted from the light source 2305 is reflected from the spatial light modulator and coupled into the at least one waveguide 2348 to be directed to the user's eye. The configuration and placement of these elements, particularly the polarizers and retarders, can reduce or eliminate reflections from optical surfaces within the system, such as the surface of the optical device 2320, which could otherwise cause ghost images to be visible to the user. For example, optical elements that are polarization selective and / or have a retardation (e.g., polarizers 2312, 2335 and retarders 2315, 2330, 2340) can be arranged and configured to transform linearly polarized light into circularly polarized light that changes from left-handed to right-handed or from right-handed to left-handed when reflected from an optical surface. Similarly, such polarization-selective and / or retardation-having optical elements (e.g., polarizers 2312, 2335 and retarders 2315, 2, and 2340) can be arranged and configured to transform circularly polarized light into linearly polarized light that can be attenuated or filtered by a polarizer (e.g., a linear polarizer). Circular polarizers that transform linearly polarized light into circularly polarized light or vice versa and can selectively filter linearly polarized light can be fabricated using such polarization-selective and retardation-having optical elements (e.g., polarizers 2312, 2335 and retarders 2315, 2330, 2340). For example, a circular polarizer can include a linear polarizer and a quarter-wave retarder. A circular polarizer can be used to transform linearly polarized light into circularly polarized light having a first state (e.g., handedness) and filter out circularly polarized light having a second state (e.g., handedness) different from the first state. For example, a circular polarizer can be used to transform linearly polarized light having a specific orientation into left-handed circularly polarized light and filter out right-handed circularly polarized light. A circular polarizer can also be used to transform linearly polarized light having a specific orientation into right-handed circularly polarized light and filter out left-handed circularly polarized light. Other configurations including circular polarizers or optical elements with retardation that can be used to transform linearly polarized light into circularly polarized light and then back again and can selectively filter linearly polarized light can be used to reduce back reflections from optical surfaces, as discussed below in connection with ​ and ​ discussed.

[0397] It is noted that in ​ and ​Left-handed and right-handed circular polarizations are shown respectively with clockwise and counterclockwise arrows. In addition, horizontal and vertical linear polarizations are shown respectively using horizontal arrows and dots.

[0398] As described above, ​ A configuration of an augmented reality display system 2300 is shown, in which polarizers 2312, 2335, such as linear polarizers (e.g., horizontal polarizers), and retarders 2315, 2330, 2340, such as quarter-wave retarders (e.g., quarter-wave plates), are arranged to reduce back-reflection from optical surfaces, such as the surface of optical device 2320, in the optical path that irradiates a spatial light modulator (not shown) and is reflected from the spatial light modulator. The first polarizer 2312 and the first retarder 2315 are disposed between the light source 2305 and the optical device 2320. The first polarizer 2312 is disposed between the light source 2305 and the first retarder 2315. Similarly, the first retarder 2315 is disposed between the first polarizer 2312 and the optical device 2320.

[0399] As shown, the light source 2305 emits light represented by light ray 2310. In some embodiments, the light ray 2310 may propagate through the polarization rotator 2307. The rotator 2307 is optional and can be used to rotate the polarization of light (e.g., light ray 2310) from the light source 2305. In various embodiments, the rotator 2307 can rotate the polarization angle (e.g., linear polarization angle). For example, the rotator 2307 can rotate the linear polarization of the light ray 2310 to an orientation aligned with the first polarizer 2312 so that the light ray is transmitted through the first polarizer 2312. In some embodiments, the polarization rotator 2307 may include a retarder, such as a half-wave retarder in some cases. The optical axis of the half-wave retarder can be oriented to rotate the polarization of light from the light source 2305 from vertical to horizontal or from horizontal to vertical. Alternatively, the polarization rotator 2307 can be configured to rotate the polarization angle of linearly polarized light emitted from the light source 2305 by a different amount. The polarization rotator 2307 does not need to be included in the system. For example, in embodiments where the light source 2305 emits light having the same polarization as the first polarizer 2312, the polarization rotator 2307 may not be included. As shown, light, such as light ray 2310, propagates through the polarizer 2312, shown here as a horizontal polarizer. In the case where the light from the light source 2305 is not polarized, the light transmitted through the horizontal polarizer 2312, as shown by the light ray 2310, is linearly polarized (e.g., horizontally polarized) after propagating through the polarizer 2312. Although a horizontal linear polarizer is used in this example, it should be understood that a vertical linear polarizer can be used to apply the teachings. Alternatively, linear polarizers with different orientations other than vertical or linear can also be used.

[0400] The horizontally polarized light ray 2310 travels through a retarder 2315, shown here as a quarter-wave retarder. The retarder 2315 may include sufficient retardation to transform linearly polarized light into circularly polarized light. For example, as shown by the curved (e.g., clockwise) arrow, horizontally polarized light can be transformed into left-handed circularly polarized light. In this example, the combination of the polarizer 2312 and the retarder 2315 (e.g., a quarter-wave retarder) forms a circular polarizer, herein referred to as the first circular polarizer, which can transform light of a specific linear polarization (e.g., horizontal or vertical polarization) into a specific circular polarization (e.g., left-handed or right-handed circular polarization, or right-handed or left-handed polarization). Depending on the configuration, the circular polarizer may also block light having a specific circular polarization (e.g., right-handed or left-handed circular polarization).

[0401] In some embodiments, various optical elements have birefringence. In some such cases, the retarder 2315 may include a retardation sufficient to transform linearly polarized light into circularly polarized light and need not be a quarter-wave plate. The retarder 2315 may include a retardation greater than or less than a quarter wavelength because the retardation may be contributed by other optical elements. Similarly, the retardation may be distributed among multiple optical elements. As another example, multiple retarders may be employed to provide an appropriate amount of retardation.

[0402] The circularly polarized light ray 2310 (here, left-handed circularly polarized) then propagates through the optical device 2320. At any interface in the system with a medium having a different refractive index, such as an air-to-material interface, unwanted reflections may occur. In the case where these reflections are allowed to enter at least one waveguide 2348, it can cause problems because the reflected light can be directed into the user's eye and form a "ghost" image visible in the user's eye. For example, in the case where a display uses at least one waveguide 2348 to project a first image into the viewer's eye, a second faint, repeated image that is shifted (e.g., laterally) relative to the first image may also be seen by the user. Such a "ghost" image is formed by reflections from optical surfaces and directed into the user's eye, which may be distracting or otherwise degrade the viewing experience. For example, as ​As shown, light such as reflected light 2325 can be reflected from a lens within the optical device 2320. This light can be directed towards at least one waveguide 2348 configured to direct the light into a user's eye to present an image thereto. However, in this case, the handedness of the circularly polarized light is reversed. For example, upon reflection from the lens, the direction of circular polarization is changed (e.g., from left-handed to right-handed). Then, the right-handed reflected light ray 2325 travels through the retarder 2315 and is transformed into linearly polarized light having a linear polarization that is different (e.g., orthogonal) from the linear polarization transmitted by the polarizer 2312. For example, in this case, the light reflected from the optical surface of the lens is transformed by the retarder 2315 into vertical linear polarization that is orthogonal to the polarization transmitted by the horizontal linear polarizer 2312. The horizontal linear polarizer 2312 selectively passes the horizontally polarized light and filters out the vertically polarized light. Thus, the horizontal linear polarizer 2312 attenuates and / or does not transmit the reflected light ray 2325 and prevents the reflected light ray 2325 from reaching at least one waveguide 2348, or allows at least a reduced amount of such reflected light to reach at least one waveguide 2348 or be coupled therein, for example, through a coupling optical element (e.g., one or more coupling gratings). The result is similar for left-handed circularly polarized light rays reflected from different optical surfaces of the optical device 2320 or other optical surfaces on different optical elements.

[0403] As shown, the display system 2300 further includes a second retarder 2330 (e.g., a quarter-wave retarder or quarter-wave plate) and a second polarizer 2335 (e.g., a linear polarizer) disposed between the optical device 2320 and a spatial light modulator (not shown). In some embodiments, the second retarder 2330 and the second linear polarizer 2335 can form a second circular polarizer. The second retarder 2330 is disposed between the optical device 2320 and the second polarizer 2335. Similarly, the second polarizer 2335 is disposed between the second retarder 2330 and the spatial light modulator. Thus, after propagating through the optical device 2320, the light ray 2310 can propagate through the second retarder 2330 (e.g., a quarter-wave retarder). The second retarder 2330 is configured to (e.g., appropriately orient the optical axis) such that the light ray 2310 is transformed from left-handed circular polarization to horizontal linear polarization. Similarly, the second retarder 2330 converts the circularly polarized light back to the original linearly polarized state output by the first polarizer 2312. As will be discussed below, the second retarder 2330 and the second polarizer 2312 can be used to reduce "ghost" images caused by light reflected from the spatial optical modulator that propagates through an optical surface (e.g., on an electro-optical device or lens 2320) as it travels to at least one light guide 2348.

[0404] A third retarder 2340 (e.g., a quarter-wave retarder or a quarter-wave plate) is disposed between the second polarizer 2335 and the spatial light modulator. Thus, the third retarder 2340 is disposed between the second retarder 2330 and the spatial light modulator. Additionally, in the various embodiments shown, the second polarizer 2335 is located between the second retarder 2330 and the third retarder 2340. As shown, when propagating through the second polarizer 2335, the light ray 2310 is linearly polarized, and in some embodiments, the second retarder 2330 / second polarizer 2335 can transform the light into the original linear polarization (e.g., horizontal polarization) of the first polarizer 2312. This linearly polarized light is incident on the third retarder 2340. The third retarder 2340 is configured such that the light ray is transformed back into circularly polarized light and, in some embodiments, into the same polarization as that output by the first retarder 2315 (in this example, e.g., left-handed circularly polarized light). In certain implementations, the spatial light modulator is configured to operate on the circularly polarized light. In some embodiments, the spatial light modulator is a reflective spatial light modulator that reflects the incident circularly polarized light back as circularly polarized light. In some embodiments, the circularly polarized light reflected from the spatial light modulator may have the same handedness (e.g., left-handed circular polarization) as the circularly polarized light incident on the spatial light modulator, possibly depending on whether the spatial light modulator pixels are in the "on" or "off" state. In some embodiments, the spatial light modulator may reflect circularly polarized light with a handedness different from that of the circularly polarized light incident on it (e.g., right-handed circular polarization), possibly depending on whether the spatial light modulator pixels are in the "on" or "off" state. However, other types of spatial light modulators may also be used.

[0405] ​Shows light (shown as ray 2342) that is reflected from the spatial light modulator and travels towards waveguide 2385. The reflected ray 2342 is shown as left-handed circularly polarized light. Ray 2342 propagates through a third retarder 2340. The third retarder 2340 transforms the circularly polarized light into linearly polarized light. In this example, the left-handed circularly polarized light is transformed into horizontally polarized light. The linearly polarized light is transmitted through a second polarizer 2335. In this example, the horizontally polarized light propagates through the second polarizer 2335. The linearly polarized light is incident on a second retarder 2330 and is transformed into circularly polarized light. In this example, the horizontally polarized light is transformed into left-handed polarized light and is transmitted into the optical device 2320. Also herein, reflections from optical surfaces, such as the surface of the optical device 2320 having a focal power, can form ghost images by being reflected back from the spatial light modulator into at least one waveguide 2348 and reaching the user's eye. As described above, unwanted reflections can occur at any interface with a medium having a different refractive index, such as an air-to-material interface. As described above, including the second retarder 2330 and the polarizer 2335 can attenuate these reflections and reduce the likelihood of ghost reflections. For example, ​ Shows light (shown as ray 2346) that is reflected from the optical surface of the optical device 2320. In this example, the act of reflection from the surface causes the reflected ray 2346 to switch the circular polarization handedness from left-handed circular polarization to right-handed circular polarization. The switched circularly polarized light is attenuated by a second circular polarizer formed by the second retarder 2330 and the polarizer 2335. For example, as ​ shown, the reflected circularly polarized light 2346 is incident on the second retarder 2330 and is transformed by the second retarder into linearly polarized light that has a different (e.g., orthogonal) linear polarization from the linear polarization selectively transmitted by the second linear polarizer 2335. In this case, for example, the right-handed circularly polarized light reflected from the optical surface of the optical device 2320 is transformed by the retarder 2330 into vertically linearly polarized light that is orthogonal to the polarization selectively transmitted by the polarizer 2335. The second polarizer 2335 attenuates or blocks the transmission of this linearly polarized light. In this example, the light 2346 is vertically polarized, while the second polarizer 2335 is a horizontal polarizer that selectively passes horizontally polarized light and filters out vertically polarized light.

[0406] In contrast, the light 2342 that propagates through the optical device 2320 and is incident on the first retarder 2315 is circularly polarized and has a handedness different from that of the light reflected from the optical surface of the optical device 2320. The light 2342 that is directed toward at least one waveguide 2348 has a polarization (e.g., left-handed polarization) that is transformed by the first retarder 2315 into a linear polarization (e.g., horizontally linearly polarized light) that is selectively transmitted by the first polarizer 2312. In this way, the light 2342 can reach and be coupled into at least one waveguide 2348 and be directed to the user's eye.

[0407] In ​ In the example shown, a first circular polarizer formed by the first polarizer 2312 and the first retarder 2315 and a second circular polarizer formed by the second retarder 2330 and the second polarizer 2335 are used to reduce reflections that may cause "ghosting". The two circular polarizers are located on opposite sides of the optical device 2320, one closer to the light source 2305 and one closer to the spatial light modulator. An additional retarder 2340 is included between the second circular polarizer (e.g., the second polarizer 2335) and the spatial light modulator to transform the light into circularly polarized light. However, various variations are possible. For example, only one circular polarizer may be included. Alternatively, additional circular polarizers or other types of polarization optical devices may be included.

[0408] ​ A third circular polarizer that can be added to an augmented reality system 2300 such as ​ shown is illustrated. In particular, ​ a second circular polarizer including the second polarizer 2335 and the second retarder 2330 and the third retarder 2340 introduced above is illustrated, and the spatial light modulator 2375 is further illustrated. The spatial light modulator (SLM) 2375 may include a liquid crystal spatial light modulator (e.g., liquid crystal on silicon or LCOS). In some embodiments, the SLM 2375 may be covered by a cover glass 2370.

[0409] ​ A third circular polarizer is also illustrated, which includes a fourth retarder 2345, such as a quarter-wave retarder (e.g., a quarter-wave plate), and a third polarizer 2355, such as a linear polarizer disposed between the second circular polarizer including the second polarizer 2335 and the second retarder 2330 and the spatial light modulator 2375. The third polarizer 2355 is located between the fourth retarder 2345 and the spatial light modulator 2375. An additional fifth retarder 2360, such as a quarter-wave retarder (e.g., a quarter-wave plate), and a compensator 2365 are disposed between the third circular polarizer including the fourth retarder 2345 and the third polarizer 2355 and the spatial light modulator 2375 or more specifically​ Between the cover glass 2370 shown. The fifth retarder 2360 is located between the third polarizer 2355 and the compensator 2365. The compensator 2365 is located between the fifth retarder 2360 and the spatial light modulator 2375 or more specifically the cover glass 2370.

[0410] ​ Shows the light from the light source 2305, such as the light ray 2310 (as ​ shown), can propagate through the second circular polarizer including the retarder 2330, the second polarizer 2335, and the third retarder 2340 to reach the third circular polarizer including the fourth retarder 2345 and the third polarizer 2355. The light ray 2310 from the light source 2305 is incident on the third circular polarizer, specifically on the fourth retarder 2345, after propagating through the second circular polarizer including the second retarder 2330 and the second polarizer 2335. The fourth retarder 2345 can transform the circularly polarized light of the light ray 2310 into linearly polarized light. In ​ the example shown, the light ray 2310 is circularly polarized (e.g., left-handed circularly polarized) and is transformed into linearly polarized light (e.g., horizontally polarized light) by the fourth retarder 2345. This linearly polarized light advances through the third polarizer 2355, and the third polarizer 2355 includes a horizontal polarizer in ​ that selectively transmits horizontally polarized light. This linearly polarized light propagates through the fifth retarder 2360, and the fifth retarder 2360 can include a quarter-wave retarder that transforms the linearly polarized light into circularly polarized light. In ​ the example shown, the horizontally linearly polarized light 2310 incident on the fifth retarder 2360 is transformed into left-handed circularly polarized light. This circularly polarized light is incident on the compensator 2365 and propagates through the compensator 2365. The compensator 2365 can include a polarization element that adjusts the polarization to the desired polarization. The compensator 2365 can be used to cancel the birefringence of various optical elements in the system. For example, due to the delay contribution of one or more optical elements, the light may be slightly elliptically polarized. In various embodiments, the light output from the compensator 2365 is circularly polarized light. In ​ the example shown, the light output from the compensator 2365 is left-handed circularly polarized light. In various embodiments, the compensator 2365 can be used to compensate for the remaining delay in the SLM, which can include, for example, a liquid crystal (e.g., LCOS) SLM cell. The compensator can introduce in-plane delay and / or out-of-plane delay. In some embodiments, the compensator 2365 can include a combination of optical retarders that, when combined, produce a delay that can potentially cancel the remaining delay from the SLM (e.g., the LCOS panel).

[0411] In ​In [the figure], the light after passing through compensator 2365 is incident on cover glass 2370 and SLM 2375. The light incident on cover glass 2370 and SLM 2375 is shown as left-handed circularly polarized light. Depending on the type and state of the spatial modulator, SLM 2375 can reflect circularly polarized light with the same handedness. For example, when the pixels of SLM 2375 are in the "on" state (although in some embodiments, this state may be the undriven state), SLM 2375 can introduce a quarter-wavelength delay each time the light passes through SLM 2375. Thus, upon reflection, the incident circularly polarized light can remain circularly polarized. In various configurations, the handedness can also remain the same. For example, as ​ shown, the incident left-handed circularly polarized light can remain left-handed circularly polarized upon reflection. The circularly polarized light reflected from SLM 2375, represented by ray 2342, can pass through cover glass 2370 and compensator 2365 and be incident on fifth retarder 2360, which transforms the circularly polarized light into linearly polarized light. In ​ the example shown, the circularly polarized light incident on fifth retarder 2360 is left-handed, and fifth retarder 2360 transforms the circularly polarized light into horizontally polarized light. Third polarizer 2355 can be configured to selectively transmit the polarization of the light output by fifth retarder 2360. Thus, in ​ the example where the light output from fifth retarder 2360 is horizontally polarized as shown, third polarizer 2355 selectively transmits the horizontally polarized light. The linearly polarized light transmitted by polarizer 2355 is incident on fourth retarder 2345 and is transformed into circularly polarized light. In ​ the example shown, the circularly polarized light is left-handed circularly polarized. As described above in connection with ​ this, the light can travel through a second circular polarizer including second retarder 2330 and second polarizer 2335, optical device 2320, and a first circular polarizer including first polarizer 2312 and first retarder 2315 to reach at least one waveguide 2348 and enter the user's eye.

[0412] However, the light reflected from the optical surface can be attenuated by the third circular polarizer, thereby reducing the likelihood that such reflections reach at least one waveguide 2348 and are directed to the user's eye to produce ghosting. For illustration, ​An example ray 2343 is shown that is reflected from an optical surface of the third retarder 2340, such as from an interface between air and the third retarder 2340. As described above, reflection can occur at any interface between media having different refractive indices, such as an air-to-material interface or an interface between different dielectric layers. However, the handedness of circularly polarized light is reversed upon reflection. For example, when reflected from the surface of the third retarder 2340, the direction of circular polarization changes (e.g., from left-handed to right-handed). The right-handed reflected ray 2343 then travels through the fourth retarder 2345 and is transformed into linearly polarized light that has a linear polarization that is different from, e.g., orthogonal to, the polarization selectively transmitted by the third polarizer 2355. In this case, for example, light reflected from the optical surface of the third retarder 2340 is transformed by the fourth retarder 2345 into vertically linearly polarized light that is orthogonal to the polarization selectively transmitted by the third polarizer 2355. The third polarizer 2355 selectively passes horizontally polarized light and filters out vertically polarized light. Thus, the third polarizer 2355 attenuates and / or does not transmit the reflected ray 2343 and prevents the reflected ray 2343 from reaching at least one waveguide 2348 (e.g., by reflecting from another surface), or allows at least a reduced amount of such reflected light to reach at least one waveguide 2348 or be coupled therein.

[0413] For circularly polarized rays reflected from different optical surfaces, the result may be similar. For example, ​ An example of reflection of an incident ray 2310 from an optical surface of the fourth retarder 2345 is shown. The reflection 2350 from the fourth retarder 2345 switches the handedness of the polarization. For example, the incident ray 2310, shown as left-handed circularly polarized, is transformed into a ray 2350 shown as having right-handed circular polarization upon reflection. The reflected ray 2350 propagates through the third retarder 2340 and is transformed into vertically polarized light. This vertically polarized light is selectively attenuated or filtered out by the second polarizer 2335.

[0414] As described above, the pixels of the SLM 2375 can be, for example, in an "on" state (although in some embodiments it can be a non-driven state), in which light incident on that pixel of the SLM 2375 is reflected therefrom and coupled into at least one waveguide 2348 and directed to the user's eye. However, the pixels of the SLM 2375 can be in an "off" state (in some embodiments it can be a driven state), in which light incident on the pixels of the SLM 2375 is not coupled into at least one waveguide 2348 and not into the user's eye. For example, in such an "off" state, various embodiments of the SLM 2375 do not introduce any delay upon reflection. Thus, in ​In the example shown, the circularly polarized light incident on the SLM 2375 can remain circularly polarized when reflected from the SLM 2375. However, the handedness of the circularly polarized light can be changed when reflected from the SLM 2375. For example, ​ the light ray 2310 shown, which is left-handed circularly polarized incident on the SLM 2375, can be transformed into right-handed circularly polarized light when reflected from the SLM 2375. However, this reflected light can be selectively attenuated by the third polarizer 2355. For example, the right-handed circularly polarized light reflected from the SLM 2375 can propagate through the cover glass 2370, the compensator 2365, and the fifth retarder 2360. The fifth retarder 2360 can transform the right-handed circularly polarized light into vertically polarized light, which is selectively attenuated by the third polarizer 2355 that can include a horizontal polarizer. Thus, in various embodiments, when the pixels of the SLM are in the "off" state, the fifth retarder 2360 can transform the light reflected from the pixels of the SLM 2375 into a linear polarization orthogonal to the linear polarization selectively transmitted by the third polarizer 2355. Thus, the third polarizer 2355 can selectively attenuate this linearly polarized light, thereby reducing or blocking the light from the pixels of the SLM 2375 from reaching at least one waveguide 2348 and being directed into the eye.

[0415] Changes in configuration are possible, such as changes in polarization optics. For example, more or fewer circular polarizers can be included. In various embodiments, for example, as ​ shown, the third circular polarizer including the fourth retarder 2345 and the third polarizer 2355 is excluded. In this particular embodiment, the fourth retarder 2345, the third polarizer 2355, and the fifth retarder 2360 are not included in the system. ​ The design of the augmented reality system 2300 is shown, which includes ​ and ​ the components shown, but does not include the fourth retarder 2345, the third polarizer 2355, and the fifth retarder 2360. However, although the third circular polarizer is excluded, the augmented reality display system is still configured to reduce ghost images. For example, the second circular polarizer reduces reflections that would otherwise cause ghosting. For illustration, ​The light reflected from the third retarder 2340 is shown as ray 2380. The act of reflection from the surface of the third retarder 2340 causes the circularly polarized reflected ray 2380 to switch its handedness. In this example, the polarization switches from left-handed circular polarization to right-handed circular polarization. Then, the switched circularly polarized light 2380 propagates through the compensator 2365 and is incident on the cover glass 2370 and the SLM 2375. As described above, the SLM 2375 can reflect circularly polarized light of the same handedness. Thus, the incident right-handed circularly polarized light can remain right-handed circularly polarized upon reflection. Then, the circularly polarized light reflected from the SLM 2375, represented by ray 2382, can propagate through the cover glass 2370 and the compensator 2365 and be incident on the third retarder 2340. The switched circularly polarized light 2382 is attenuated by the second circular polarizer, specifically by the third retarder 2340 and the polarizer 2335. For example, as Figure 23C shown, the circularly polarized light 2382 reflected from the SLM 2375 is incident on the third retarder 2340 and is transformed by the third retarder 2340 into linearly polarized light having a linear polarization different from, e.g., orthogonal to, the linear polarization selectively transmitted by the second linear polarizer 2335. In this case, for example, the right-handed circularly polarized light 2382 is transformed by the third retarder 2340 into vertically linearly polarized light that is orthogonal to the polarization selectively transmitted by the second polarizer 2335. The second polarizer 2335 attenuates or blocks the transmission of such linearly polarized light.

[0416] By tilting the optical surfaces in the system, reflections that can cause ghost reflections can also potentially be reduced. Figure 24 An example configuration with tilted optical surfaces for reducing reflections that can produce ghost reflections is shown. Figure 24 An augmented reality display system 2400 is shown that includes a light source 2305 that emits light represented by ray 2310, which will propagate through any number of polarizers, retarders, lenses, and / or other optical components as the light travels towards a spatial light modulator (SLM). For purposes of illustration, in Figure 24Shown therein are a first polarizer 2312, a first retarder 2315, and a lens 2320 that may form a first circular polarizer. However, additional components may be included, or components may be excluded or arranged or configured in a different manner. In the example shown, the SLM 2375 includes a cover glass 2370. The cover glass 2370 may be a contributing factor to the reflections that produce ghost images. Thus, in some embodiments, the shape of the cover glass 2370 can be designed to direct reflections that can produce ghost images such that they are not directed into the user's eye. As shown, the cover glass 2370 has a surface that is tilted such that the surface is not parallel to other components or optical surfaces of the system (such as the SLM 2375, the first retarder 2315, the first polarizer 2312, at least one waveguide 2348, etc. or their optical surfaces). The major surface of the cover glass 2370 may, for example, have a tilted normal such that it is not aligned or parallel with the optical axis of the augmented reality display system 2400 or optical components therein (such as the optic 2320). By tilting, reflections from the optical surface of the cover glass 2370 can be directed away from at least one waveguide 2348 or an optical coupling element (such as a coupling grating or diffractive optical element) for coupling light into at least one waveguide 2348, and reduce the likelihood of reflections from the cover glass 2370 entering at least one waveguide 2348. As shown, the reflected light 2405 is directed back towards the light source 2305 and away from at least one waveguide 2348, where such light could ultimately reach the user's eye. In some embodiments, the reflected light 2405 can be directed back to the light source and at least a portion thereof is recycled at the light source 2305.

[0417] Although Figure 24 a cover glass 2370 with a tilted surface is shown, an optical surface that prevents reflections from being coupled into at least one waveguide 2348 by tilting can be included on any system component where unwanted reflections may occur. Thus, the optical surfaces on other components such as polarizers, retarders, etc. can be tilted to reduce the reflections that are coupled into at least one waveguide 2348 and reach the user's eye. Variations in the shape and size of the cover glass 2370 or other optical components are possible. The cover glass 2370 or other optical components can, for example, be thinner. Similarly, the cover glass 2370 or other optical components can have an aspect ratio (length to thickness ratio) Figure 24 different from that shown. In some embodiments, the cover glass 2370 or other optical components are wedge shaped. However, other shapes are possible.

[0418] Other arrangements are possible. For example, Figure 25 shown is similar to Figure 24An implementation of the augmented reality display system 2500 of the system 2400 shown, but further includes a light absorber 2505 to absorb the light guided to the light absorber. The system 2500 includes an inclined cover glass 2370 to guide the reflection 2510 from the cover glass 2370 to the light absorber 2505 instead of guiding it back to the light source 2305. The light absorber 2505 may include an absorbing material or structure configured to absorb light. Depending on the implementation, for example, depending on the angle of the inclined cover glass 2370, the position of the light absorber 2505 can be changed. As described above, the method can be applied to other optical surfaces in the system. Additionally, the shape and size of the optical elements can be different.

[0419] A variety of variations in the augmented reality display are possible. Variations in the polarization optical elements are possible. For example, although a horizontal polarizer is used, in some implementations, a vertical polarizer or a combination of a horizontal polarizer and a vertical polarizer can also be employed. Additionally, a polarizer characterized by polarization other than vertical or horizontal polarization can be used. Similarly, the light shown in the figure does not have to be horizontally polarized and can also be vertically polarized. Similarly, in different implementations, the light shown as vertically polarized can be horizontally polarized, or the light shown as horizontally polarized can be vertically polarized. Linearly polarized light with polarization other than vertical or horizontal can also be used.

[0420] Furthermore, the retarder can be configured in different ways. For example, the polarized light in the figure does not have to be left-handed circularly polarized and can also be right-handed circularly polarized and / or the right-handed polarized light can be left-handed circularly polarized. Other variations are possible. Different retarder configurations can be employed to produce combinations of polarized light different from the left-handed and / or right-handed polarized light shown. Additionally, in some implementations, elliptically polarized light can be used instead of circularly polarized light. For example, a retarder can be used to transform elliptically polarized light into linearly polarized light, or linearly polarized light into elliptically polarized light. A linear polarizer can be used to filter light and can be used to reduce ghost reflections such as those described herein.

[0421] In some embodiments, other types of polarization elements and their configurations are employed. For example, retarders are not limited to quarter-wave retarders or quarter-wave plates. For instance, in some embodiments, various optical elements have birefringence. In certain such cases, any one or more of retarders 2315, 2330, 2340 can include a retardation amount sufficient to transform linearly polarized light into circularly polarized light and need not be a quarter-wave retarder. Any one or more of retarders 2315, 2330, 2340 can include more or less than a quarter-wave of retardation since the retardation can be contributed by other optical elements. Similarly, the retardation can be distributed among multiple optical elements. As another example, multiple retarders can be employed to provide an appropriate amount of retardation. Additionally, as described above, in some embodiments, elliptically polarized light can be used instead of circularly polarized light. For example, a retarder can be used to transform elliptically polarized light into linearly polarized light, or linearly polarized light into elliptically polarized light. Linear polarizers can be used to filter light and can be used to reduce ghost reflections such as those described herein.

[0422] Additionally, the optical components can be in the form of optical layers, sheets, and / or films and stacks or one or more layers, sheets, and / or films. Thus, different polarization elements with different numbers, positions, and arrangements can be used. For example, one or more of the retarders and / or polarizers can include a film.

[0423] In some embodiments, the spatial light modulator can operate in different ways. For example, the spatial light modulator can operate on light other than circularly polarized light and / or can output light other than circularly polarized light.

[0424] In the foregoing specification, the disclosure has been described with reference to specific embodiments of the disclosure. However, it will be apparent that various modifications and changes can be made to the disclosure without departing from the broader spirit and scope of the disclosure. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive.

[0425] In fact, it should be understood that the systems and methods of the disclosure each have several innovative aspects, none of which alone is responsible for or requires the desired attributes disclosed herein. The various features and processes described above can be used independently of one another or can be combined in various ways. All possible combinations and sub-combinations are intended to fall within the scope of the disclosure.

[0426] Certain features that are described in the context of separate embodiments in this specification can also be implemented in combination in a single embodiment. Conversely, the various features that are described in the context of a single embodiment can also be implemented separately in multiple embodiments, or in any suitable sub-combination. Additionally, although features may operate in certain combinations as described above, and even be claimed initially in this manner, one or more features in the claimed combination can in some cases be excluded from the combination, and the claimed combination can relate to a sub-combination or a variation of a sub-combination. For each embodiment, no single feature or group of features is necessary or indispensable.

[0427] It should be understood that, unless expressly stated otherwise or otherwise understood in the context in which it is used, conditional language such as "able to", "can", "may", "could", "for example", etc., used herein is generally intended to mean that certain embodiments include, while other embodiments do not include, certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that the features, elements, and / or steps are in any way necessary for one or more embodiments, nor is it intended to imply that one or more embodiments necessarily include logic for determining whether to include such features, elements, and / or steps or whether to perform such features, elements, and / or steps in any particular embodiment, with or without author input or prompting. The terms "comprising", "including", "having", etc. are synonyms and are used inclusively in an open-ended manner and do not exclude other elements, features, acts, operations, etc. Further, the term "or" is used in an inclusive sense (and not an exclusive sense), so that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Additionally, unless otherwise specified, the articles "a", "an", and "the" used in this application and the appended claims should be construed to mean "one or more" or "at least one". Similarly, although operations are shown in the figures as taking a particular order, it should be recognized that these operations need not be performed in the particular order shown or sequentially, or that all of the shown operations are performed to achieve the desired result. Further, the figures may schematically depict one or more example processes in the form of a flowchart. However, other operations not shown may be incorporated into the example methods and processes schematically illustrated. For example, one or more additional operations may be performed before, after, between, or in parallel with any of the shown operations. Additionally, in other embodiments, the operations may be rearranged or reordered. In some cases, multitasking and parallel processing are advantageous. Further, the separation of the various system components in the above embodiments should not be understood to be required in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other embodiments are within the scope of the following claims. In some cases, the acts recited in the claims can be performed in a different order and still achieve the desired result.

[0428] Accordingly, the claims are not intended to be limited to the embodiments shown herein but are to be accorded the broadest scope consistent with the disclosure, principles, and novel features disclosed herein.

Claims

1. A display system configured to project light into a user's eye, the display system comprising: At least one light source; A spatial light modulator having one or more pixels and configured to form an image; And At least one waveguide having a first major surface and a second major surface disposed in the X-Z plane and opposite the first major surface, and a first edge and a second edge between the first major surface and the second major surface, the spatial light modulator being closer to the first major surface of the at least one waveguide, and the at least one light source being closer to the second major surface of the at least one waveguide, wherein a diffractive optical element is disposed on the second major surface, Wherein the display system is configured such that light from the light source is received into the at least one waveguide through the second major surface at a first position in the X-Z plane and transmitted towards the spatial light modulator through the first major surface such that the light from the light source does not pass through the diffractive optical element, and at least a portion of the light illuminating the spatial light modulator is redirected back at a second position offset from the first position in the X-Z plane and diffractively coupled into the at least one waveguide by the diffractive optical element for guiding therein, and Wherein the at least one waveguide is configured to be positioned on the user's head in front of the user's eye such that at least a portion of the light diffractively coupled into the at least one waveguide and guided therein is output from the at least one waveguide to the user's eye to display image content to the user.

2. The display system according to claim 1, wherein, The at least one light source includes a plurality of laterally disposed light emitters configured to output light.

3. The display system according to claim 1, further comprising a reflective coupling optical device configured to collect light output from the light source.

4. The display system according to claim 3, wherein, The coupling optical device includes a compound parabolic concentrator (CPC).

5. The display system according to claim 1, wherein: The at least one waveguide includes a waveguide stack.

6. A display system comprising: At least one waveguide, comprising: A first major surface; A second major surface opposite the first major surface; A first edge and a second edge between the first major surface and the second major surface; and A first reflector disposed between the first major surface and the second major surface; At least one light source; and A spatial light modulator configured to form an image and disposed closer to the first major surface than the second major surface, wherein the first reflector is configured to reflect light from the at least one light source towards the spatial light modulator.

7. An augmented reality optical system comprising: A set of illumination sources, comprising: A first illumination source characterized by a first wavelength and disposed at a first lateral position; A second illumination source characterized by a second wavelength and disposed at a second lateral position offset 120 degrees from the first lateral position; and A third illumination source characterized by a third wavelength and disposed at a third lateral position offset -120 degrees from the first lateral position; An eyepiece waveguide stack, which is arranged near the set of illumination sources and includes: A first waveguide layer, including: A first coupling-in diffraction element, which is arranged at a fourth lateral position offset by 180 degrees from the first lateral position; and A first coupling-out diffraction element, which is optically coupled to the first coupling-in diffraction element; A second waveguide layer, including: A second coupling-in diffraction element, which is arranged at a fifth lateral position offset by 180 degrees from the second lateral position; and A second coupling-out diffraction element, which is optically coupled to the second coupling-in diffraction element; and A third waveguide layer, including: A third coupling-in diffraction element, which is arranged at a sixth lateral position offset by 180 degrees from the third lateral position; and A third coupling-out diffraction element, which is optically coupled to the third coupling-in diffraction element; A lens assembly, which is arranged near the eyepiece waveguide stack; and A spatial light modulator, which is arranged near the lens assembly.

8. An augmented reality optical system, including: A set of illumination sources, including: A first illumination source, which is characterized by a green wavelength range and is arranged at an angle of zero degrees in a polar coordinate system; A second illumination source, which is characterized by a blue wavelength range and is arranged at an angle of 120 degrees in the polar coordinate system; and A third illumination source, which is characterized by a red wavelength range and is arranged at an angle of 240 degrees in the polar coordinate system; and An eyepiece waveguide stack, which is arranged near the set of illumination sources and includes: A first waveguide layer, including a first coupling-in diffraction element, the first coupling-in diffraction element being operable to diffract light in the green wavelength range and being arranged at an angle of 180 degrees in the polar coordinate system; A second waveguide layer, including a second coupling-in diffraction element, the second coupling-in diffraction element being operable to diffract light in the blue wavelength range and being arranged at an angle of 300 degrees in the polar coordinate system; and A third waveguide layer, including a third coupling-in diffraction element, the third coupling-in diffraction element being operable to diffract light in the red wavelength range and being arranged at an angle of 60 degrees in the polar coordinate system.

9. An augmented reality optical system, including: A set of illumination sources, including: A first illumination source, which is characterized by a first wavelength and is arranged at a first lateral position; A second illumination source, which is characterized by a second wavelength and is arranged at a second lateral position offset by 120 degrees from the first lateral position; and A third illumination source, which is characterized by a third wavelength and is arranged at a third lateral position offset by -120 degrees from the first lateral position, wherein the first illumination source is characterized in that a first lateral luminous area is smaller than a second lateral luminous area corresponding to the second illumination source and a third lateral luminous area corresponding to the third illumination source; An eyepiece waveguide stack, which is arranged near the set of illumination sources and includes: A first waveguide layer, including: A first coupling-in diffraction element, which is arranged at a fourth lateral position offset by 180 degrees from the first lateral position; and A first coupling-out diffraction element, which is optically coupled to the first coupling-in diffraction element; A second waveguide layer, including: A second input diffraction element, which is disposed at a fifth lateral position offset by 180 degrees from the second lateral position; and A second output diffraction element, which is optically coupled to the second input diffraction element; and A third waveguide layer, comprising: A third input diffraction element, which is disposed at a sixth lateral position offset by 180 degrees from the third lateral position; and A third output diffraction element, which is optically coupled to the third input diffraction element; A lens assembly, which is disposed near the eyepiece waveguide stack; and A spatial light modulator, which is disposed near the lens assembly.

10. A display system, comprising: At least one light source, which is configured to output light; An optical device, which has a focal power and is configured to receive the output light, wherein the output light is incident on a first side of the optical device and transmitted through a second side of the optical device; and A spatial light modulator, which is configured to: Receive the output light transmitted through the second side of the optical device; Form image light using the output light transmitted through the second side of the optical device; and Project the image light onto the second side of the optical device, wherein the image light is incident on the second side of the optical device, transmitted through the optical device, and emitted from the first side of the optical device.

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