Series-intercoupled optical elements

Abstract

The display system includes a waveguide assembly having multiple waveguides, each associated with an incoupling optical element configured to incoupling light into the associated waveguide. The projector outputs light from one or more spatially separated pupils, with at least one of the pupils outputting light in two different wavelength ranges. The incoupling optical elements for the two or more waveguides are in-line, e.g., vertically aligned, with each other so that the incoupling optical elements are in the paths of light in the two different wavelength ranges. The incoupling optical element of a first waveguide selectively incouples light in one wavelength range into the waveguide, while the incoupling optical element of a second waveguide selectively incouples light in another wavelength range. An absorptive color filter is provided in front of the incoupling optical element to limit the propagation of undesired wavelengths of light into the incoupling optical element.

Description

[Technical field]

[0001] (Priority Claim) This application claims priority from U.S. Provisional Application No. 62 / 800,316, filed February 1, 2019, and entitled “INLINE IN-COUPLING OPTICAL ELEMENTS,” which is incorporated by reference in its entirety herein.

[0002] The present disclosure relates to optical systems, including augmented reality imaging and visualization systems. [Background technology]

[0003] 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 may be perceived as real. Virtual reality, or "VR", scenarios typically involve the presentation of digital or virtual image information without transparency to other actual real-world visual inputs, and augmented reality, or "AR", scenarios typically involve the presentation of digital or virtual image information as an extension to the visualization of the real world around the user. Mixed reality, or "MR", scenarios are a type of AR scenario that typically involve virtual objects that are integrated into and responsive to the natural world. For example, MR scenarios may include AR image content that appears occluded by or is otherwise perceived to interact with objects in the real world.

[0004] Referring to FIG. 1, an augmented reality scene 10 is depicted. A user of the AR technology sees a real-world park-like setting 20 featuring people, trees, buildings in the background, and a concrete platform 30. The user also "sees" and perceives "virtual content," such as a robotic figure 40 standing on the real-world platform 30, and a flying cartoon-like avatar character 50 that appears to be an anthropomorphic bumblebee. These elements 50, 40 are "virtual" in that they do not exist in the real world. The human visual perception system is complex, and it is difficult to produce AR technology that facilitates a comfortable, natural-feeling, and rich presentation of virtual image elements among other virtual or real-world image elements.

[0005] The systems and methods disclosed herein address various challenges associated with AR or VR technology. Summary of the Invention [Means for solving the problem]

[0006] The head mounted display system may be configured to project light into the user's eye and display the augmented reality image content within the user's field of view. The head mounted display system may include a frame configured to be supported on the user's head. The head mounted display system may also include an eyepiece disposed on the frame. At least a portion of the eyepiece may be transparent and / or disposed in a location in front of the user's eye when the user wears the head mounted display such that the transparent portion transmits light from an environment in front of the user to the user's eye to provide a view of that environment in front of the user. The eyepiece may include one or more wave guides disposed to direct light into the user's eye and form the augmented reality image content.

[0007] Various embodiments of the head mounted display system include a projector having a pupil that outputs light (e.g., image light) having a plurality of wavelength ranges (e.g., two or three wavelength ranges). Each wavelength range may include one or more wavelengths. In some embodiments, the head mounted display system includes a waveguide assembly including a plurality of waveguides stacked over one another and configured to receive light having a plurality of wavelength ranges output from the projector pupil. Each waveguide in the plurality of waveguides may include an internal coupling optical element configured to internally couple light of one of the plurality of wavelength ranges from the light output from the projector pupil. Various embodiments of the head mounted display system may include a projector having two separated pupils, one of the separated pupils configured to output light having a first wavelength range and a second wavelength range different from the first wavelength range, and another of the separated pupils configured to output light of a third wavelength range different from the first wavelength range and the second wavelength range. In some such embodiments, the head mounted display system comprises a waveguide assembly comprising at least three waveguides stacked over one another and configured to receive light in a first wavelength range, a second wavelength range, and a third wavelength range output from two separated pupils of the projector. Each of the at least three waveguides in the waveguide assembly comprises a first in-coupling optical element configured to in-couple light in the first wavelength range, a second in-coupling optical element configured to in-coupling light in the second wavelength range, and a third in-coupling optical element configured to in-coupling light in the third wavelength range. The first in-coupling optical element and the second in-coupling optical element are configured to in-coupling light in the first and second wavelength ranges output from one of the separated pupils. The first in-coupling optical element and the second in-coupling optical element may at least partially spatially overlap, while the third in-coupling optical element configured to in-coupling light of the third wavelength may be spatially separated from the first in-coupling optical element and the second in-coupling optical element.

[0008] In some embodiments, a display system is provided. The display system includes a projection system for outputting image light to form a full color image. The display system also includes a stack of waveguides. The stack of waveguides includes a first waveguide having a first incoupling optical element configured to receive the image light and incoupling the image light of a first primary color. The stack of waveguides also includes a second waveguide underlying the first waveguide and having a second incoupling optical element configured to receive the image light and incoupling the image light of a second primary color. The first incoupling optical element and the second incoupling optical element are laterally displaced relative to each other by 5-50% of the shortest width of the first and second incoupling optical elements when viewed in a top-down view.

[0009] In some embodiments, the first and second in-coupling optical elements are laterally displaced relative to each other by 10-25% of the shortest width of the first and second in-coupling optical elements when viewed in a top-down view. In some embodiments, the projection system has a single exit pupil for outputting the image light. In some embodiments, the display system further comprises a color filter in the optical path of the image light, the color filter being disposed between the first and second in-coupling optical elements. The color filter may be laterally displaced by the same amount relative to the first in-coupling optical element as the second in-coupling optical element. In some embodiments, the color filter is an absorptive color filter. In some embodiments, the display system further comprises a third waveguide underlying the second waveguide and having a third in-coupling optical element configured to receive the image light and in-couple image light of a third primary color. In some embodiments, the third in-coupling optical element is laterally displaced relative to the second in-coupling optical element by 5-50% of the shortest width of the second and third in-coupling optical elements when viewed in a top-down view. In some embodiments, the first, second, and third incoupling optical elements constitute a first set of waveguides for forming an image on a first depth plane, and the display system further comprises a second set of waveguides for forming an image on a second depth plane, the first and second sets of waveguides outputting light with different amounts of wavefront divergence from one another. In some embodiments, the second set of waveguides comprises fourth, fifth, and sixth waveguides, each having a respective fourth, fifth, and sixth incoupling optical element. In some embodiments, the fourth and fifth incoupling optical elements are laterally displaced relative to one another by 5-50% of the shortest width of the fourth and fifth incoupling optical elements when viewed in a top-down view. In some embodiments, the fifth and sixth incoupling optical elements are laterally displaced relative to one another by 5-50% of the shortest width of the fifth and sixth incoupling optical elements when viewed in a top-down view.

[0010] The systems, methods, and devices disclosed herein each have several innovative aspects, no one of which is solely responsible for the desirable attributes disclosed herein. Various exemplary systems and methods are provided below.

[0011] Example 1 1. A display system comprising: a first absorptive optical filter that is transmissive to light in a first wavelength range and absorptive to light at a wavelength different from the first wavelength range; a first incoupling optical element configured to receive light transmitted through the first absorptive optical filter; a first waveguide having a first major surface and a second major surface; wherein the first incoupling optical element is configured to incoupling light of a first wavelength range into the first waveguide. a stack of waveguides; Display system.

[0012] Example 2 2. The display system of example 1, wherein the first incoupling optical element is on a first major surface of the first waveguide or a second major surface of the first waveguide.

[0013] Example 3 a second absorptive optical filter on one or both of the first or second major surfaces of the first waveguide; When viewed in a top-down view, the first absorbing optical filter is laterally displaced from the second absorbing optical filter. The display system according to any one of Examples 1-2.

[0014] Example 4 The display system of any of Examples 1-3, wherein the first absorptive optical filter comprises a dye.

[0015] Example 5 The display system of any of Examples 1-4, wherein the first internal coupling optical element is configured to transmit light having a range of wavelengths different from the first range of wavelengths.

[0016] Example 6 The waveguide stack further comprises: a second waveguide having a first major surface and a second major surface; a second incoupling optical element configured to incoupling light transmitted through the first absorptive optical filter and the first incoupling optical element and having a second range of wavelengths different from the first range of wavelengths into a second waveguide; The display system according to any one of Examples 1 to 5, comprising:

[0017] Example 7 7. The display system of example 6, wherein the second incoupling optical element is on a first major surface of the second waveguide or a second major surface of the second waveguide.

[0018] Example 8 A display system according to any of Examples 6-7, wherein at least a portion of the first internal coupling optical element and at least a portion of the second internal coupling optical element laterally overlap each other when viewed in a top-down view.

[0019] Example 9 The second waveguide is in front of the first waveguide; a third absorptive optical filter on a major surface of the second waveguide and laterally displaced from the second incoupling optical element, the third absorptive optical filter configured to absorb incoupling light having a wavelength different from the second range of wavelengths; A display system according to any one of Examples 7-8.

[0020] Example 10 10. The display system of example 9, wherein the third absorptive optical filter comprises a dye.

[0021] Example 11 a third waveguide aft of the first waveguide, the third waveguide having a first major surface and a second major surface; a third incoupling optical element configured to incoupling light from the incident beam of light having a third wavelength range into the third waveguide; The display system of any one of Examples 6-10, further comprising:

[0022] Example 12 12. The display system of example 11, wherein the third internal coupling optical element is on one of the first major surface of the third waveguide or the second major surface of the third waveguide.

[0023] Example 13 The display system of any of Examples 11-12, wherein at least a portion of the third incoupling optical element laterally overlaps with the first incoupling optical element and the second incoupling optical element.

[0024] Example 14 The display system of any of Examples 11-13, further comprising a fourth absorptive optical filter between the second waveguide and the third waveguide in front of the third internal coupling optical element.

[0025] Example 15 15. The display system of example 14, wherein the third optical filter comprises a dye.

[0026] Example 16 1. A display system comprising: a first waveguide having a first major surface and a second major surface; a first incoupling optical element configured to receive a first incident beam of light; wherein the first incoupling optical element is configured to incoupling light from an incident beam of light having a first wavelength range into the first waveguide. a first waveguide assembly; a second waveguide having a first major surface and a second major surface; a second incoupling optical element configured to receive a second incident beam of light; and the second incoupling optical element is configured to incoupling light from a second incident beam of light having a second wavelength range into the second waveguide; the first incoupling optical element and the second incoupling optical element are laterally displaced from each other when viewed in a top-down view toward major surfaces of the first and second waveguides. a second waveguide assembly; a stack of waveguide assemblies comprising: Display system.

[0027] (Example 17) The stack of waveguide assemblies includes: a third waveguide having a first major surface and a second major surface; a third incoupling optical element configured to receive a first incident beam of light, the third incoupling optical element configured to incoupling light from the incident beam of light into a third waveguide, the third incoupling optical element having a third wavelength range different from the first wavelength range and the second wavelength range; an optical filter between the first waveguide and the third waveguide, the optical filter configured to absorb light from the incident beam of light having a first wavelength and transmit light from the incident beam of light having a third wavelength range; a third waveguide assembly comprising: The display system of Example 16.

[0028] (Example 18) 18. The display system of Example 17, wherein at least a portion of the first incoupling optical element overlaps with a portion of the third input optical element when viewed in a top-down view.

[0029] (Example 19) A display system as described in any of Examples 17-18, further comprising a second optical filter on one of the first or second major surfaces of the first waveguide, the second optical filter being laterally displaced from the first internal coupling optical element when viewed in a top-down view, the second optical filter being configured to absorb internally coupled light in the first waveguide having a wavelength range different from the first wavelength range.

[0030] (Example 20) A display system as described in any of Examples 17-19, further comprising a third optical filter on one of the first or second major surfaces of the second waveguide, the third optical filter being laterally displaced from the second internal coupling optical element, the third optical filter being configured to absorb internally coupled light in the second waveguide having a wavelength range different from the second wavelength range.

[0031] Example 21 and a fourth optical filter on one of the first or second major surfaces of the third waveguide, the fourth optical filter being between the second waveguide and the third waveguide, the fourth optical filter comprising: Absorbs light having a first wavelength range and a second wavelength range; transmits light having a third wavelength range; A display system according to any one of Examples 17-20, configured as follows:

[0032] Example 22 1. A display system comprising: a projection system for outputting image light for forming a full color image; a first waveguide having a first incoupling optical element configured to receive the image light and to incoupling the image light of a first primary color; a second waveguide underlying the first waveguide and having a second incoupling optical element configured to receive the image light and incoupling image light of a second primary color; wherein the first and second internal coupling optical elements are laterally displaced relative to each other by 5 to 50% of the shortest width of the first and second internal coupling optical elements when viewed in top-down view. a waveguide stack; A display system comprising:

[0033] (Example 23) The display system of Example 22, wherein the first internal coupling optical element and the second internal coupling optical element are laterally displaced relative to each other by 10 to 25% of the shortest width of the first and second internal coupling optical elements when viewed in top-down view.

[0034] Example 24 23. The display system of example 22, wherein the projection system has a single exit pupil for outputting the image light.

[0035] (Example 25) 23. The display system of Example 22, further comprising a color filter in the optical path of the image light, the color filter being disposed between the first internal coupling optical element and the second internal coupling optical element.

[0036] (Example 26) 26. The display system of example 25, wherein the color filter is laterally displaced relative to the first incoupling optical element by the same amount as the second incoupling optical element.

[0037] Example 27 26. The display system of Example 25, wherein the color filter is an absorptive color filter.

[0038] (Example 28) The display system of Example 22, further comprising a third waveguide having a third internal coupling optical element underlying the second waveguide and configured to receive the image light and internally couple image light of a third primary color.

[0039] (Example 29) The display system of Example 28, wherein the third internal coupling optical element is laterally displaced relative to the second internal coupling optical element by 5 to 50% of the shortest width of the second and third internal coupling optical elements when viewed in top-down view.

[0040] (Example 30) the first, second, and third internal coupling optical elements form a first set of waveguides for forming an image on a first depth plane; and a second set of waveguides for forming an image on a second depth plane, the first and second sets of waveguides outputting light with different amounts of wavefront divergence from one another. The display system of Example 28.

[0041] (Example 31) The display system of Example 30, wherein the second set of waveguides comprises fourth, fifth, and sixth waveguides each having respective fourth, fifth, and sixth internal coupling optical elements.

[0042] Example 32 The display system of Example 31, wherein the fourth internal coupling optical element and the fifth internal coupling optical element are laterally displaced relative to each other by 5 to 50% of the shortest width of the fourth and fifth internal coupling optical elements when viewed in top-down view.

[0043] (Example 33) The display system of Example 32, wherein the fifth and sixth internal coupling optical elements are laterally displaced relative to each other by 5 to 50% of the shortest width of the fifth and sixth internal coupling optical elements when viewed in top-down view. The present specification also provides, for example, the following items: (Item 1) 1. A display system comprising: 1. A stack of waveguides, the stack of waveguides comprising: a first absorptive optical filter, the first absorptive optical filter being transmissive to light in a first wavelength range and absorptive to light at a wavelength different from the first wavelength range; a first incoupling optical element configured to receive light transmitted through the first absorptive optical filter; a first waveguide having a first major surface and a second major surface; Equipped with the first incoupling optical element is configured to incoupling light of the first wavelength range into the first waveguide; Waveguide Stack A display system comprising: (Item 2) 2. The display system of claim 1, wherein the first internal coupling optical element is on a first major surface of the first waveguide or on a second major surface of the first waveguide. (Item 3) a second absorptive optical filter on one or both of the first or second major surfaces of the first waveguide; when viewed in a top-down view, the first absorbing optical filter is laterally displaced from the second absorbing optical filter. Item 1. A display system according to any one of items 1 to 5. (Item 4) Item 13. The display system of any of items 1, wherein the first absorptive optical filter comprises a dye. (Item 5) Item 2. The display system of any of the preceding items, wherein the first internal coupling optical element is configured to transmit light having a range of wavelengths different from the first range of wavelengths. (Item 6) The waveguide stack further comprises: a second waveguide having a first major surface and a second major surface; a second incoupling optical element configured to incoupling light transmitted through the first absorptive optical filter and the first incoupling optical element and having a second range of wavelengths different from the first range of wavelengths into the second waveguide; Item 2. The display system of any of items 1, comprising: (Item 7) 7. The display system of any of items 6, wherein at least a portion of the first internal coupling optical element and at least a portion of the second internal coupling optical element laterally overlap each other when viewed in a top-down view. (Item 8) a third waveguide aft of the first waveguide, the third waveguide having a first major surface and a second major surface; a third incoupling optical element configured to incoupling light from an incident beam of light having a third wavelength range into the third waveguide; 7. The display system of any of items 6, further comprising: (Item 9) 9. The display system of claim 8, wherein the third internal coupling optical element is on one of a first major surface of the third waveguide or a second major surface of the third waveguide. (Item 10) Item 9. The display system of any of items 8, wherein at least a portion of the third incoupling optical element laterally overlaps the first incoupling optical element and the second incoupling optical element. (Item 11) 9. The display system of any of claims 8, further comprising a fourth absorptive optical filter between the second waveguide and the third waveguide in front of the third internal coupling optical element. (Item 12) Item 12. The display system of item 11, wherein the third optical filter comprises a dye. (Item 13) 7. The display system of claim 6, wherein the second internal coupling optical element is on a first major surface of the second waveguide or on a second major surface of the second waveguide. (Item 14) the second waveguide is in front of the first waveguide; a third absorptive optical filter on a major surface of the second waveguide and laterally displaced from the second incoupling optical element, the third absorptive optical filter configured to absorb incoupling light having a wavelength different from the second range of wavelengths. Item 14. The display system of any of items 13, further comprising: (Item 15) Item 15. The display system of item 14, wherein the third absorptive optical filter comprises a dye. (Item 16) 1. A display system comprising: 1. A stack of waveguide assemblies, the stack of waveguide assemblies comprising: A first waveguide assembly, the first waveguide assembly comprising: a first waveguide having a first major surface and a second major surface; a first internal coupling optical element configured to receive a first incident beam of light; Equipped with the first incoupling optical element is configured to incoupling light from the incident beam of light having a first wavelength range into the first waveguide. a first waveguide assembly; A second waveguide assembly, the second waveguide assembly comprising: a second waveguide having a first major surface and a second major surface; a second incoupling optical element configured to receive a second incident beam of light; and Equipped with the second incoupling optical element is configured to incoupling light from a second incident beam of light having a second wavelength range into the second waveguide; the first and second incoupling optical elements are laterally displaced from one another when viewed in a top-down view toward major surfaces of the first and second waveguides. a second waveguide assembly; A stack of waveguide assemblies comprising: A display system comprising: (Item 17) The stack of waveguide assemblies comprises: A third waveguide assembly, the third waveguide assembly comprising: a third waveguide having a first major surface and a second major surface; a third incoupling optical element configured to receive the first incident beam of light, the third incoupling optical element configured to incoupling light from the incident beam of light having a third wavelength range different than the first wavelength range and the second wavelength range into the third waveguide; an optical filter between the first waveguide and the third waveguide, the optical filter configured to absorb light from the incident beam of light having the first wavelength and transmit light from the incident beam of light having the third wavelength range; and A third waveguide assembly comprising: Item 17. The display system of item 16, comprising: (Item 18) Item 18. The display system of item 17, wherein at least a portion of the first internal coupling optical element overlaps with a portion of the third input optical element when viewed in the top-down view. (Item 19) Item 18. The display system of any of items 17, further comprising a second optical filter on one of the first or second major surfaces of the first waveguide, the second optical filter being laterally displaced from the first internal coupling optical element when viewed in the top-down view, the second optical filter being configured to absorb internally coupled light in the first waveguide having a wavelength range different from the first wavelength range. (Item 20) Item 18. The display system of any of items 17, further comprising a third optical filter on one of the first or second major surfaces of the second waveguide, the third optical filter being laterally displaced from the second internal coupling optical element, the third optical filter being configured to absorb internally coupled light in the second waveguide having a wavelength range different from the second wavelength range. (Item 21) and a fourth optical filter on one of the first or second major surfaces of the third waveguide, the fourth optical filter being between the second waveguide and the third waveguide, the fourth optical filter comprising: absorbing light having the first wavelength range and the second wavelength range; transmitting light having the third wavelength range; 20. The display system of any of items 17, configured to: (Item 22) 1. A display system comprising: a projection system for outputting image light for forming a full color image; 1. A stack of waveguides, the stack of waveguides comprising: a first waveguide having a first incoupling optical element configured to receive the image light and to incoupling image light of a first primary color; a second waveguide, the second waveguide underlying the first waveguide and having a second incoupling optical element configured to receive the image light and incoupling image light of a second primary color; Equipped with the first internal coupling optical element and the second internal coupling optical element are laterally displaced relative to each other by 5 to 50% of the shortest width of the first and second internal coupling optical elements when viewed in top-down view; Waveguide stack and A display system comprising: (Item 23) 23. The display system of claim 22, wherein the first and second internal coupling optical elements are laterally displaced relative to each other by 10-25% of the shortest width of the first and second internal coupling optical elements when viewed in a top-down view. (Item 24) 23. The display system of claim 22, wherein the projection system has a single exit pupil for outputting the image light. (Item 25) 23. The display system of claim 22, further comprising a color filter in an optical path of the image light, the color filter being disposed between the first internal coupling optical element and the second internal coupling optical element. (Item 26) Item 26. The display system of item 25, wherein the color filter is displaced laterally relative to the first incoupling optical element by the same amount as the second incoupling optical element. (Item 27) 26. The display system of claim 25, wherein the color filter is an absorptive color filter. (Item 28) a third waveguide, the third waveguide underlying the second waveguide and having a third incoupling optical element configured to receive the image light and to incoupling image light of a third primary color; 23. The display system of claim 22, further comprising: (Item 29) Item 29. The display system of item 28, wherein the third internal coupling optical element is displaced laterally relative to the second internal coupling optical element by 5 to 50% of the shortest width of the second and third internal coupling optical elements when viewed in a top-down view. (Item 30) the first, second, and third internal coupling optical elements form a first set of waveguides for forming an image at a first depth plane; and a second set of waveguides for forming an image on a second depth plane, the first and second sets of waveguides outputting light with different amounts of wavefront divergence from one another. Item 29. The display system of item 28. (Item 31) Item 31. The display system of item 30, wherein the second set of waveguides comprises fourth, fifth, and sixth waveguides each having respective fourth, fifth, and sixth internal coupling optical elements. (Item 32) Item 32. The display system of item 31, wherein the fourth internal coupling optical element and the fifth internal coupling optical element are laterally displaced relative to each other by 5 to 50% of the shortest width of the fourth and fifth internal coupling optical elements when viewed in a top-down view. (Item 33) Item 33. The display system of item 32, wherein the fifth and sixth internal coupling optical elements are laterally displaced relative to each other by 5-50% of the shortest width of the fifth and sixth internal coupling optical elements when viewed in a top-down view. [Brief description of the drawings]

[0044] [Figure 1] FIG. 1 illustrates a user's view of an augmented reality (AR) device, according to some embodiments.

[0045] [Diagram 2] FIG. 2 illustrates an example of a wearable display system, according to some embodiments.

[0046] [Diagram 3] FIG. 3 illustrates a display system for simulating a three-dimensional image for a user, according to some embodiments.

[0047] [Figure 4] FIG. 4 illustrates aspects of an approach for simulating a three-dimensional image using multiple depth planes, according to some embodiments.

[0048] [Diagram 5] 5A-5C illustrate the relationship between the radius of curvature and the focal radius, according to some embodiments.

[0049] [Figure 6] FIG. 6 illustrates an example of a waveguide stack for outputting image information to a user, according to some embodiments.

[0050] [Figure 7] FIG. 7 illustrates an example of an output beam output by a waveguide, according to some embodiments.

[0051] [Figure 8] FIG. 8 illustrates an example of a stacked waveguide assembly in which each depth plane contains an image formed using multiple different primary colors, according to some embodiments.

[0052] [Figure 9A]FIG. 9A illustrates a cross-sectional side view of an example of a set of stacked waveguides, each including an internal coupling optical element, according to some embodiments.

[0053] [Figure 9B] FIG. 9B illustrates a perspective view of an example of the stacked waveguide set of FIG. 9A, according to some embodiments.

[0054] [Figure 9C] FIG. 9C illustrates a top-down plan view of the set of stacked waveguide examples of FIGS. 9A and 9B, according to some embodiments.

[0055] [Figure 10] FIG. 10 diagrammatically illustrates a perspective view of an example of a split-pupil waveguide assembly comprising multiple waveguides stacked over one another and an internal coupling optical element configured to internally couple light output from a projector that outputs image light from two spatially separated pupils.

[0056] [Figure 10A] FIG. 10A illustrates a side view of the waveguide assembly illustrated in FIG. 10 along plane 10A-10A.

[0057] [Figure 11] FIG. 11 diagrammatically illustrates a perspective view of an example of a waveguide assembly comprising multiple waveguides stacked over one another and an internal coupling optical element configured to internally couple light output from a projector having a single pupil.

[0058] [Figure 11A] FIG. 11A illustrates a side view of the waveguide assembly illustrated in FIG. 11 along plane 11A-11A.

[0059] [Figure 12]FIG. 12 diagrammatically illustrates a perspective view of an example of a split-pupil waveguide assembly comprising multiple waveguides stacked over one another, an internal coupling optical element configured to internally couple light output from a projector having two spatially separated pupils, and multiple color / wavelength filters.

[0060] [Figure 12A] FIG. 12A diagrammatically illustrates a side view of the embodiment illustrated in FIG.

[0061] [Figure 13] FIG. 13 diagrammatically illustrates a perspective view of an example of a single-pupil waveguide assembly comprising multiple waveguides stacked over one another, an internal coupling optical element configured to internally couple light from a projector having a single pupil, and multiple color / wavelength filters.

[0062] [Figure 13A] FIG. 13A illustrates a side view of the embodiment illustrated in FIG.

[0063] [Figure 14] 14A and 14B diagrammatically illustrate side views of an example of a waveguide assembly comprising multiple waveguides stacked over one another and internal coupling optical elements configured to internally couple light of two different wavelengths, the internal coupling optical elements being displaced relative to one another to improve color selectivity.

[0064] [Figure 15A] FIG. 15A diagrammatically illustrates a side view of an example of a waveguide assembly comprising multiple waveguides stacked over one another and internal coupling optical elements configured to internally couple light of two different wavelengths, the internal coupling optical elements being displaced relative to one another to improve color selectivity.

[0065] [Figure 15B]FIG. 15B diagrammatically illustrates a side view of an embodiment of a waveguide assembly similar to that of FIG. 12A, with an internal coupling optical element laterally displaced.

[0066] [Figure 16] FIG. 16 graphically illustrates the variation of the incoupling efficiency of an incoupling optical element for positive and negative angles of incidence.

[0067] [Figure 17] FIG. 17 diagrammatically illustrates a side view of an embodiment of a stacked waveguide assembly for a dual depth planar display system.

[0068] The drawings are provided to illustrate example embodiments and are not intended to limit the scope of the present disclosure.Like reference numbers refer to like parts throughout. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0069] VR and AR experiences may be provided by a display system having a display in which images corresponding to multiple depth planes are provided to the viewer. The images may be different for each depth plane (e.g., providing slightly different presentations of a scene or object) and may be focused separately by the viewer's eyes, thereby helping to provide a depth cue to the user based on ocular accommodation. It should be understood that ocular accommodation may focus different content located on different depth planes within a scene. As discussed herein, such depth cues help provide a reliable perception of depth by the viewer.

[0070] In some configurations, a full-color image may be formed for various depth planes by overlaying component images, each having a particular primary color. For example, red, green, and blue images may each be output to form a respective full-color image. As a result, each depth plane may have multiple primary color images associated with it. As disclosed herein, the primary color images may be output using a waveguide that in-couples light containing image information, disperses the in-coupled light across the waveguide, and then out-couples the light towards a viewer. Light may be in-coupled into the waveguide using an in-coupling optical element, such as a diffractive element, and then out-coupled out of the waveguide using an out-coupling optical element, which may also be a diffractive element.

[0071] The images for the different depth planes may be generated by a projector that outputs light from a plurality of spatially separated pupils. For example, the projector may be configured to output a plurality of primary color images for the different depth planes from a plurality of spatially separated pupils. Consider a display system configured to present color images to a user at two different depth planes, forming each full color image using three primary color images. Some such embodiments of the display system may include a first set of three waveguides stacked relative to each other with respect to a first depth plane and a second set of three waveguides stacked relative to each other with respect to a second depth plane. The first and second sets of waveguides may be stacked relative to each other. Each waveguide in the first and second sets of three waveguides may be configured to output an image to a viewer in one color (e.g., blue, green, or red). In such an embodiment of the display system, the projector may be configured to have six spatially separated pupils. A first set of three spatially separated pupils may be configured to output red, green, and blue images for a first depth plane, and a second set of three spatially separated pupils may be configured to output red, green, and blue images for a second depth plane.

[0072] Without being bound to any particular theory, the fewer pupils output from a projector, the smaller the projector may typically be. Thus, reducing the number of spatially separated pupils output by a projector may advantageously reduce the size of the projector, and thus the overall size of the display system. Thus, it may be advantageous to configure the projector in the embodiments of the display system discussed above to output light at fewer than six spatially separated pupils in order to reduce the footprint of the projector, and thus the overall display system.

[0073] For example, a projector may be configured to output light of a first wavelength (e.g., red wavelength) and a second wavelength (e.g., blue wavelength) different from the first wavelength from a first pupil with respect to a first depth plane, and output light of a third wavelength (e.g., green wavelength) with respect to the first depth plane from a second pupil that is spatially separated from the first pupil. Thus, instead of having three spatially separated pupils that output light of a first wavelength, a second wavelength, and a third wavelength with respect to the first depth plane, two spatially separated pupils are used to output light of three different wavelengths with respect to the first depth plane. It should be understood that, for brevity and ease of explanation herein, a single wavelength (e.g., red, green, or blue) is referenced, and reference to a single wavelength should be understood to include a range of wavelengths that encompasses the single wavelength.

[0074] In this embodiment, among the first set of waveguides configured to output an image at a first depth plane, a first in-coupling optical element is configured to in-couple light at a first wavelength, and a second in-coupling optical element is configured to in-couple light at a second wavelength. The in-coupling optical elements may be vertically aligned with each other to partially spatially overlap with the second in-coupling optical element when viewed in a top-down view, such that at least a portion of the first in-coupling optical element receives light at the first and second wavelengths output from a first pupil, in other words, the in-coupling optical elements may be in series, in the sense that the in-coupling optical elements are in the path of light output from the same projector pupil. The third in-coupling optical element is positioned to receive light at a third wavelength from a second pupil that is spatially separated from the first pupil. Thus, the third in-coupling optical element need not be vertically aligned with the first and second in-coupling optical elements, but may instead be spatially separated from the first and second in-coupling optical elements. Thus, the third incoupling optical element need not spatially overlap (either partially or completely) with the first incoupling optical element and the second incoupling optical element.

[0075] As another example, a projector may be configured to output light of a first wavelength (e.g., a red wavelength), a second wavelength different from the first wavelength (e.g., a blue wavelength), and a third wavelength (e.g., a green wavelength) from a single pupil for a first depth plane. Thus, instead of having three spatially separated pupils that output light of the first wavelength, the second wavelength, and the third wavelength for the first depth plane, a single pupil is used to output light of the three different wavelengths for the first depth plane.

[0076] In this example, within the first set of waveguides, a first incoupling optical element is configured to incoupling light at a first wavelength, a second incoupling optical element is configured to incoupling light at a second wavelength, and a third incoupling optical element is configured to incoupling light at a third wavelength. The first, second, and third incoupling optical elements may be vertically aligned to spatially overlap one another to receive light at the first wavelength, the second wavelength, and the third wavelength output from a single pupil.

[0077] In various embodiments, the first and / or second set of waveguides may include one or more wavelength-selective filters (also referred to as color filters) to reduce crosstalk between incoupling light of different wavelengths and / or reduce ghosting. Preferably, the color filters are absorptive color filters, e.g., layers of light-absorbing material. In some embodiments, the color filters may be placed between pairs of vertically aligned incoupling optical elements. It should be understood that an incoupling optical element may not incoupling all of the incident light of a particular wavelength into an associated waveguide, such that some of the light of that wavelength propagates to an underlying incoupling optical element configured to incoupling light of another wavelength. To limit the propagation of undesired wavelengths of light from the first incoupling optical element to the second incoupling optical element, color filters configured to absorb undesired wavelengths of light may be provided between the incoupling optical elements. Additionally, in some embodiments, color filters may be provided on one or both major surfaces of the waveguides to absorb unintentionally incoupling light propagating through the waveguides.

[0078] Reference will now be made to the drawings, in which like reference numbers refer to like parts throughout.

[0079] FIG. 2 illustrates an example of a wearable display system 60. The display system 60 includes a display 70 and various mechanical and electronic modules and systems to support the functionality of the display 70. The display 70 may be coupled to a frame 80 that is wearable by a display system user or viewer 90 and configured to position the display 70 in front of the eye of the user 90. The display 70 may be considered eyewear in some embodiments. In some embodiments, a speaker 100 is coupled to the frame 80 and configured to be positioned adjacent to the ear canal of the user 90 (in some embodiments, another speaker, not shown, may also be optionally positioned adjacent the user's other ear canal to provide stereo / shapeable sound control). The display system may also include one or more microphones 110 or other devices to detect sound. In some embodiments, the microphones may be configured to allow the user to provide input or commands (e.g., voice menu command selections, natural language questions, etc.) to the system 60 and / or enable audio communication with other persons (e.g., other users of similar display systems). The microphone may further be configured as an ambient sensor to collect audio data (e.g., sounds from the user and / or the environment). In some embodiments, the display system may also include an ambient sensor 120a that is separate from the frame 80 and may be mounted on the body of the user 90 (e.g., on the head, torso, limbs, etc. of the user 90). The ambient sensor 120a may, in some embodiments, be configured to obtain data that characterizes a physiological state of the user 90. For example, the sensor 120a may be an electrode.

[0080] 2, the display 70 is operably coupled by a communication link 130, such as by wired or wireless connectivity, to a local data processing module 140, which may be mounted in a variety of configurations, such as fixedly attached to the frame 80, fixedly attached to a helmet or hat worn by the user, built into headphones, or otherwise removably attached to the user 90 (e.g., in a backpack configuration, in a belt-coupled configuration). Similarly, the sensor 120a may be operably coupled to the local processor and data module 140 by a communication link 120b, such as by wired or wireless connectivity. The local processing and data module 140 may comprise a hardware processor and digital memory, such as non-volatile memory (e.g., flash memory or hard disk drive), both of which may be utilized to aid in processing, caching, and storing data. The data includes a) data captured from sensors (e.g., which may 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, wireless devices, gyroscopes, and / or other sensors disclosed herein, and / or b) data obtained and / or processed using the remote processing module 150 and / or remote data repository 160 (including data related to the virtual content), possibly for passing to the display 70 after processing or retrieval. The local processing and data module 140 may be operatively coupled to the remote processing module 150 and the remote data repository 160 by 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 available as resources to the local processing and data module 140.In some embodiments, local processing and data module 140 may include one or more of an image capture device, a microphone, an inertial measurement unit, an accelerometer, a compass, a GPS unit, a wireless device, and / or a gyroscope. In some other embodiments, one or more of these sensors may be mounted to frame 80 or may be a freestanding structure that communicates with local processing and data module 140 by a wired or wireless communication path.

[0081] 2, in some embodiments, the remote processing module 150 may comprise one or more processors configured to analyze and process the data and / or image information. In some embodiments, the remote data repository 160 may comprise a digital data storage facility, which may be available through the Internet or other networking 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, for example, information for generating augmented reality content. In some embodiments, all data is stored and all calculations are performed in the local processing and data module, allowing for fully autonomous use from the remote modules.

[0082] Referring now to FIG. 3, the perception of an image as "three-dimensional" or "3-D" may be achieved by providing a slightly different presentation of the image to each eye of a viewer. FIG. 3 illustrates a conventional display system for simulating a three-dimensional image for a user. Two distinct images 190, 200 are output to the user, one for each eye 210, 220. The images 190, 200 are spaced apart from the eyes 210, 220 by a distance 230 along an optical axis or z-axis parallel to the viewer's line of sight. The images 190, 200 are flat, and the eyes 210, 220 may focus on the images by assuming a single accommodated state. Such a 3-D display system relies on the human visual system to combine the images 190, 200 and provide a perception of depth and / or scale of the combined image.

[0083] However, it should be appreciated that the human visual system is more complex and more difficult to provide a realistic perception of depth. For example, many viewers of conventional "3-D" display systems may find such systems uncomfortable or may not perceive any sensation of depth at all. Without being limited by theory, it is believed that a viewer of an object may perceive the object as "three-dimensional" due to a combination of vergence-divergence and accommodation. The vergence-divergence movement of the two eyes relative to one another (i.e., the rotation of the eyes such that the pupils move toward or away from one another, converging the gaze of the eyes and fixating on the object) is closely linked to the focusing (or "accommodation") of the eye's lens and pupil. Under normal conditions, changing the focus of the eye's lens or accommodating the eye to change focus from one object to another at a different distance will automatically produce a corresponding change in vergence-divergence to the same distance, under a relationship known as the "accommodation-vergence-divergence reflex" and pupil dilation or constriction. Similarly, changes in vergence-divergence will induce corresponding changes in accommodation of lens shape and pupil size under normal conditions. As described herein, many stereoscopic or "3-D" display systems display a scene using a slightly different presentation (and therefore a slightly different image) to each eye so that a three-dimensional perspective is perceived by the human visual system. However, such systems are uncomfortable for many viewers because, among other things, they simply provide a different presentation of the scene but work against the "accommodation-vergence-divergence reflex" when the eyes view the entire image information in a single accommodated state. Display systems that provide a better match between accommodation and vergence-divergence may produce a more realistic and comfortable simulation of a three-dimensional image.

[0084] FIG. 4 illustrates aspects of an approach for simulating a three-dimensional image using multiple depth planes. With reference to FIG. 4, objects at various distances from the eyes 210, 220 on the z-axis are accommodated by the eyes 210, 220 such that the objects are in focus. The eyes 210, 220 assume a particular accommodated state and focus objects at different distances along the z-axis. As a result, a particular accommodated state may be said to be associated with a particular one of the depth planes 240 having an associated focal length such that an object or part of an object at a particular depth plane is in focus when the eye is in an accommodated state for that depth plane. In some embodiments, a three-dimensional image may be simulated by providing a different presentation of an image for each eye 210, 220 and by providing a different presentation of an image corresponding to each of the depth planes. Although shown as separate for clarity of illustration, it should be understood that the fields of view of the eyes 210, 220 may overlap, for example, as the distance along the z-axis increases. Additionally, although shown as flat for ease of illustration, it should be understood that the contour of the depth plane may be curved in physical space such that all features within the depth plane are in focus with the eye in a particular accommodated state.

[0085] The distance between an object and the eye 210 or 220 may also change the amount of divergence of light from that object as viewed by that eye. Figures 5A-5C illustrate the relationship between distance and divergence of light rays. The distance between the object and the eye 210 is represented in the order of decreasing distances R1, R2, and R3. As shown in Figures 5A-5C, the light rays become more divergent as the distance to the object decreases. As the distance increases, the light rays become more collimated. In other words, the light field generated by a point (an object or part of an object) may be said to have a spherical wavefront curvature that is a function of the distance the point is away from the user's eye. The curvature increases with decreasing distance between the object and the eye 210. As a result, at different depth planes, the divergence of the light rays is also different, and the divergence increases with decreasing distance between the depth plane and the viewer's eye 210. Although only a monocular 210 is illustrated in FIGS. 5A-5C and other figures herein for clarity of illustration, it should be understood that the discussion regarding eye 210 may apply to both eyes 210 and 220 of a viewer.

[0086] Without being limited by theory, it is believed that the human eye can typically interpret a finite number of depth planes to provide depth perception. As a result, a highly realistic simulation of perceived depth can be achieved by providing the eye with different presentations of images corresponding to each of these limited number of depth planes. The different presentations can be focused separately by the viewer's eye, thereby serving to provide depth cues to the user based on the ocular accommodation required to focus different image features for a scene located on the different depth planes and / or based on the observation of different image features on the different depth planes being out of focus.

[0087] FIG. 6 illustrates an example of a waveguide stack for outputting image information to a user. The display system 250 includes a stack of waveguides or a stacked waveguide assembly 260 that can be utilized to provide a three-dimensional perception to the eye / brain using multiple waveguides 270, 280, 290, 300, 310. In some embodiments, the display system 250 is the system 60 of FIG. 2, and FIG. 6 illustrates several portions of the system 60 in greater detail. For example, the waveguide assembly 260 may be part of the display 70 of FIG. 2. It should be understood that the display system 250 may be considered a light field display in some embodiments. In addition, the waveguide assembly 260 may also be referred to as an eyepiece.

[0088] Continuing with reference to FIG. 6, the waveguide assembly 260 may also include a number of features 320, 330, 340, 350 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 number of lenses 320, 330, 340, 350 may be configured to transmit image information to the eye with various levels of wavefront curvature or light beam divergence. 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 input devices 360, 370, 380, 390, 400 may act as light sources for the waveguides and may be utilized to input image information into the waveguides 270, 280, 290, 300, 310, which may be configured to distribute incident light across each individual waveguide for output towards the eye 210, as described herein. Light exits output surfaces 410, 420, 430, 440, 450 of the image input devices 360, 370, 380, 390, 400 and is input into 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 portion of a major surface of the corresponding waveguide (i.e., one of the waveguide surfaces that directly faces the world 510 or the viewer's eye 210). In some embodiments, a single light beam (e.g., a collimated beam) may be launched into each waveguide and output a total field of cloned collimated beams that are directed toward the eye 210 at a particular angle (and divergence) corresponding to the depth plane associated with the particular waveguide. In some embodiments, a single one of the image launch devices 360, 370, 380, 390, 400 may be associated with and launch light into multiple (e.g., three) waveguides 270, 280, 290, 300, 310.

[0089] In some embodiments, each of the image input devices 360, 370, 380, 390, 400 is a discrete display that generates image information for input into a corresponding waveguide 270, 280, 290, 300, 310, respectively. In some other embodiments, the image input devices 360, 370, 380, 390, 400 are the output of a single multiplexed display that may send image information to each of the image input devices 360, 370, 380, 390, 400, for example, via one or more optical conduits (such as fiber optic cables). It should be understood that the image information provided by the image input devices 360, 370, 380, 390, 400 may include light of different wavelengths or colors (e.g., different primary colors as discussed herein).

[0090] In some embodiments, the light injected into the waveguides 270, 280, 290, 300, 310 is provided by a light projector system 520 comprising a light module 540, which may include light emitters such as light emitting diodes (LEDs). Light from the light module 540 may be directed through a beam splitter 550 to and modified by a light modulator 530, e.g., a spatial light modulator. The light modulator 530 may be configured to change the perceived intensity of the light injected into the waveguides 270, 280, 290, 300, 310. Examples of spatial light modulators include liquid crystal displays (LCDs), including liquid crystal on silicon (LCOS) displays. It should be understood that image input devices 360, 370, 380, 390, 400 are illustrated diagrammatically, and in some embodiments these image input devices may represent different light paths and locations within a common projection system that are configured to output light into associated ones of waveguides 270, 280, 290, 300, 310.

[0091] In some embodiments, the display system 250 may be a scanning fiber display comprising one or more scanning fibers configured to project light in various patterns (e.g., raster scan, spiral scan, Lissajous pattern, etc.) into one or more waveguides 270, 280, 290, 300, 310 and ultimately to the viewer's eye 210. In some embodiments, the illustrated image injection devices 360, 370, 380, 390, 400 may diagrammatically represent a single scanning fiber or a bundle of scanning fibers configured to inject light into one or more waveguides 270, 280, 290, 300, 310. In some other embodiments, the illustrated image injection devices 360, 370, 380, 390, 400 may diagrammatically represent multiple scanning fibers or multiple bundles of scanning fibers, each configured to inject light into an associated one of the waveguides 270, 280, 290, 300, 310. It is understood that one or more optical fibers may be configured to transmit light from the optical module 540 to one or more of the waveguides 270, 280, 290, 300, 310. It is understood that one or more intervening optical structures may be provided between the scanning fiber or fibers and one or more of the waveguides 270, 280, 290, 300, 310, for example, to redirect light exiting the scanning fiber into one or more of the waveguides 270, 280, 290, 300, 310.

[0092] The controller 560 controls the operation of one or more of the stacked waveguide assemblies 260, including the operation of the image input devices 360, 370, 380, 390, 400, the light source 540, and the light modulator 530. 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-transient medium) that coordinates the timing and provision of image information to the waveguides 270, 280, 290, 300, 310, for example, according to any of the various schemes disclosed herein. In some embodiments, the controller may be a single integrated device or a distributed system connected by wired or wireless communication channels. The controller 560 may be part of the processing module 140 or 150 (FIG. 2) in some embodiments.

[0093] Continuing with reference to FIG. 6, the waveguides 270, 280, 290, 300, 310 may be configured to propagate light within each individual waveguide by total internal reflection (TIR). Each of the waveguides 270, 280, 290, 300, 310 may be planar or have another shape (e.g., curved) with major top and bottom surfaces and edges extending between the major top and bottom surfaces. In the illustrated configuration, the waveguides 270, 280, 290, 300, 310 may each include an outcoupling optical element 570, 580, 590, 600, 610 configured to extract light from the waveguide by redirecting light propagating within each individual waveguide out of the waveguide and outputting image information to the eye 210. The extracted light may also be referred to as outcoupled light, and the outcoupling optical element may also be referred to as a light extraction optical element. The extracted beam of light may be output by the waveguide at a location where the light propagating within the waveguide strikes the light extraction optical element. The outcoupling optical element 570, 580, 590, 600, 610 may be a grating, for example, including diffractive optical features as further discussed herein. Although shown disposed on the bottom major surface of the waveguide 270, 280, 290, 300, 310 for ease of explanation and clarity of the drawings, in some embodiments the outcoupling optical element 570, 580, 590, 600, 610 may be disposed on the top and / or bottom major surfaces and / or directly within the volume of the waveguide 270, 280, 290, 300, 310, as further discussed herein. In some embodiments, the outcoupling optical elements 570, 580, 590, 600, 610 may be formed within a layer of material that is attached to a transparent substrate and forms the waveguide 270, 280, 290, 300, 310. In some other embodiments, the waveguide 270, 280, 290, 300, 310 may be a monolithic piece of material and the outcoupling optical elements 570, 580, 590, 600, 610 may be formed on and / or within that piece of material.

[0094] With continued reference to FIG. 6, as discussed herein, each waveguide 270, 280, 290, 300, 310 is configured to output light and form an image corresponding to a particular depth plane. For example, the waveguide 270 closest to the eye may be configured to deliver collimated light (injected into such waveguide 270) to the eye 210. The collimated light may represent an optical infinity focal plane. The next upper waveguide 280 may be configured to send collimated light that passes through a first lens 350 (e.g., a negative lens) before it can reach the eye 210. Such a first lens 350 may be configured to generate a slight convex wavefront curvature such that the eye / brain interprets the light originating from the next upper waveguide 280 as originating from a first focal plane closer inward from optical infinity toward the eye 210. Similarly, the third upper waveguide 290 may pass its output light through both the first lens 350 and the second lens 340 before reaching the eye 210, and the combined refractive power of the first lens 350 and the second lens 340 may be configured to produce another incremental amount of wavefront curvature such that the eye / brain interprets the light emerging from the third waveguide 290 as originating from a second focal plane that is closer inward from optical infinity towards the person than the light from the next upper waveguide 280.

[0095] The other waveguide layers 300, 310 and lenses 330, 320 are similarly configured, with the highest waveguide 310 in the stack sending its output through all of the lenses between it and the eye for an aggregate focal force that represents the focal plane closest to the person. To compensate the stack of lenses 320, 330, 340, 350 when viewing / interpreting light originating from the world 510 on the other side of the stacked waveguide assembly 260, a compensating lens layer 620 may be placed on top of the stack to compensate for the aggregate force of the lens stacks 320, 330, 340, 350 below. Such a configuration provides as many perceived focal planes as there are waveguide / lens pairs available. Both the outcoupling optical elements of the waveguides and the focusing sides of the lenses may be static (i.e., not dynamic or electroactive). In some alternative embodiments, either or both may be dynamic using electroactive features.

[0096] 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 images set at the same depth plane, or multiple subsets of the waveguides 270, 280, 290, 300, 310 may be configured to output images set at the same depth planes, with one set per depth plane. This may provide an advantage for forming tiled images to provide an extended field of view at those depth planes.

[0097] Continuing with reference to FIG. 6, the out-coupling optical elements 570, 580, 590, 600, 610 may be configured to redirect the light out of their respective waveguides and output this light with an appropriate amount of divergence or collimation for the particular depth plane associated with the waveguide. As a result, waveguides with different associated depth planes may have differently configured out-coupling optical elements 570, 580, 590, 600, 610 that 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 may be volume or surface features that may be configured to output light at a specific angle. For example, the light extraction optical elements 570, 580, 590, 600, 610 may be volume holograms, surface holograms, and / or diffraction gratings. In some embodiments, the features 320, 330, 340, 350 may not be lenses; rather, they may simply be spacers (eg, cladding layers and / or structures to form an air gap).

[0098] In some embodiments, the outcoupling optical elements 570, 580, 590, 600, 610 are diffractive features or "diffractive optical elements" (also referred to herein as "DOEs") that form a diffraction pattern. Preferably, the DOEs have a sufficiently low diffraction efficiency so that only a portion of the light in the beam is deflected toward the eye 210 at each intersection of the DOE, while the remainder continues to travel through the waveguide via TIR. The light carrying the image information is thus split into several related exit beams that exit the waveguide at various locations, resulting in a very uniform pattern of exit emission toward the eye 210 for this particular collimated beam bouncing within the waveguide.

[0099] In some embodiments, one or more DOEs may 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 may comprise a layer of polymer dispersed liquid crystal in which the microdroplets comprise a diffractive pattern within a host medium, and the refractive index of the microdroplets may be switched to substantially match the refractive index of the host material (in which case the pattern does not significantly diffract incident light), or the microdroplets may be switched to a refractive index that does not match that of the host medium (in which case the pattern actively diffracts incident light).

[0100] In some embodiments, a camera assembly 630 (e.g., a digital camera, including visible and infrared light cameras) may be provided to capture images of the eye 210 and / or tissue surrounding the eye 210, for example, to detect user input and / or monitor a physiological condition of the user. As used herein, a camera may be any image capture device. In some embodiments, the camera assembly 630 may include an image capture device and a light source for projecting 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 assembly 630 may be mounted on the frame 80 (FIG. 2) and may be in electrical communication with the processing modules 140 and / or 150, which may process image information from the camera assembly 630. In some embodiments, one camera assembly 630 may be utilized per eye, monitoring each eye separately.

[0101] 7, an example of an output beam output by a waveguide is shown. Although one waveguide is shown, it should be understood that other waveguides in the waveguide assembly 260 (FIG. 6) may function similarly and that the waveguide assembly 260 includes multiple waveguides. Light 640 is launched 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 impinges on the DOE 570, a portion of the light exits the waveguide as an output beam 650. The output beam 650 is shown as approximately parallel, but may be redirected to propagate to the eye 210 at an angle (e.g., forming a diverging output beam) as discussed herein and depending on the depth plane associated with the waveguide 270. It should be understood that a nearly collimated exit beam may refer to a waveguide with outcoupling optics that outcouples light to form an image that appears to be set at a depth plane at a large distance (e.g., optical infinity) from the eye 210. Other waveguides or other sets of outcoupling optics may output a more divergent exit beam pattern, which would require the eye 210 to accommodate to a closer distance and focus on the retina, and would be interpreted by the brain as light from a distance closer to the eye 210 than optical infinity.

[0102] In some embodiments, a full color image may be formed at each depth plane by overlaying an image in each of the primary colors, for example, three or more primary colors. FIG. 8 illustrates an example of a stacked waveguide assembly in which each depth plane includes an image formed using multiple different primary colors. The illustrated embodiment shows depth planes 240a-240f, but more or less depths are also contemplated. Each depth plane may have three or more primary color images associated with it, 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. The different depth planes are indicated in the diagram by different numbers for diopters (dpt) following the letters G, R, and B. Merely by way of example, the numbers following each of these letters indicate the diopters (1 / m), i.e., the inverse distance of the depth plane from the viewer, and each box in the diagram represents an individual primary color image. In some embodiments, the exact locations of the depth planes for the different primary colors may be varied to account for differences in the eye's focusing of light of different wavelengths. For example, different primary color images for a given depth plane may be placed on depth planes that correspond to different distances from the user. Such an arrangement may increase visual acuity and user comfort, and / or reduce chromatic aberration.

[0103] In some embodiments, the light of each primary color may be output by a single dedicated waveguide, such that each depth plane may have multiple waveguides associated with it. In such embodiments, each box in the figure containing the letter G, R, or B may be understood to represent an individual waveguide, and three waveguides may be provided per depth plane, with three primary color images provided per depth plane. The waveguides associated with each depth plane are shown adjacent to each other in this drawing for ease of illustration, but it should be understood that in a physical device, the waveguides may all be arranged in a stack with one waveguide per level. In some other embodiments, multiple primary colors may be output by the same waveguide, such that, for example, only a single waveguide may be provided per depth plane.

[0104] 8, in some embodiments, G is green, R is red, and B is blue. In some other embodiments, other colors associated with other wavelengths of light, including magenta and cyan, may be used in addition to or in place of one or more of red, green, or blue.

[0105] It should be understood that references throughout this disclosure to a given color of light will be understood to encompass one or more wavelengths of light within the range of wavelengths of light that are perceived by a viewer as being of that given color. For example, red light may include one or more wavelengths of light within a range of about 620-780 nm, green light may include one or more wavelengths of light within a range of about 492-577 nm, and blue light may include one or more wavelengths of light within a range of about 435-493 nm.

[0106] In some embodiments, the light source 540 (FIG. 6) may be configured to emit light at one or more wavelengths outside the range of visual perception of a viewer, e.g., infrared and / or ultraviolet wavelengths. Additionally, the waveguide in-coupling, out-coupling, and other light redirecting structures of the display 250 may be configured to direct and emit this light out of the display toward the user's eye 210, e.g., for imaging and / or user stimulation applications.

[0107] 9A, in some embodiments, light impinging on a waveguide may need to be redirected to in-couple the light into the waveguide. An in-coupling optical element may be used to redirect and in-couple the light into its corresponding waveguide. FIG. 9A illustrates a cross-sectional side view of an example of a plurality or set 660 of stacked waveguides, each including an in-coupling optical element. Each of the waveguides may be configured to output light of 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 (FIG. 6), except that light from one or more of the image injection devices 360, 370, 380, 390, 400 is injected into the waveguide from a position that requires the light to be redirected for in-coupling, and the illustrated waveguides of the stack 660 may correspond to a portion of the plurality of waveguides 270, 280, 290, 300, 310.

[0108] The illustrated set 660 of stacked waveguides includes waveguides 670, 680, and 690. Waveguide 670 is in front of, or closer to, the image source than, waveguide 680, and waveguide 690 is behind, or further from, the image source than, waveguide 680. Each waveguide includes an associated internal coupling optical element (which may also be referred to as the light input area on the waveguide), e.g., internal coupling optical element 700 is disposed on a major surface (e.g., upper major surface) of waveguide 670, internal coupling optical element 710 is disposed on a major surface (e.g., upper major surface) of waveguide 680, and internal coupling optical element 720 is disposed on a major surface (e.g., upper major surface) of waveguide 690. In some embodiments, one or more of the incoupling optical elements 700, 710, 720 may be disposed on the bottom major surface of the respective waveguide 670, 680, 690 (particularly, one or more of the incoupling optical elements are reflective polarizing optical elements). As shown, the incoupling optical elements 700, 710, 720 may be disposed on the upper major surface of the respective waveguide 670, 680, 690 (or on the top of the next lower waveguide), and particularly, the incoupling optical elements are transmissive polarizing optical elements. In some embodiments, the incoupling optical elements 700, 710, 720 may be disposed within the body of the respective waveguide 670, 680, 690. In some embodiments, as discussed herein, the incoupling optical elements 700, 710, 720 are wavelength selective to selectively redirect one or more wavelengths of light while transmitting other wavelengths of light. Although illustrated on one side or corner of their respective waveguides 670, 680, 690, it should be understood that the internal coupling optical elements 700, 710, 720 may be located within other areas of their respective waveguides 670, 680, 690 in some embodiments.

[0109] As shown, the in-coupling optical elements 700, 710, 720 may be laterally offset from one another. In some embodiments, each in-coupling optical element may be offset to receive light without that light passing through another in-coupling optical element. For example, each in-coupling optical element 700, 710, 720 may be configured to receive light from different image input devices 360, 370, 380, 390, and 400, as shown in FIG. 6, and may be separated (e.g., laterally spaced) from the other in-coupling optical elements 700, 710, 720 such that it does not receive substantially any light from other ones of the in-coupling optical elements 700, 710, 720.

[0110] Each waveguide also includes an associated optically dispersive element, for example, optically dispersive element 730 is disposed on a major surface (e.g., a top major surface) of waveguide 670, optically dispersive element 740 is disposed on a major surface (e.g., a top major surface) of waveguide 680, and optically dispersive element 750 is disposed on a major surface (e.g., a top major surface) of waveguide 690. In some other embodiments, optically dispersive elements 730, 740, 750 may be disposed on the bottom major surfaces of associated waveguides 670, 680, 690, respectively. In some other embodiments, optically dispersive elements 730, 740, 750 may be disposed on both the top and bottom major surfaces of associated waveguides 670, 680, 690, respectively, or optically dispersive elements 730, 740, 750 may be disposed on different ones of the top and bottom major surfaces in different associated waveguides 670, 680, 690, respectively.

[0111] The waveguides 670, 680, 690 may be spaced apart and separated, for example, by gas, liquid, and / or solid layers of material. For example, as shown, layer 760a may separate the waveguides 670 and 680, and layer 760b may separate the waveguides 680 and 690. In some embodiments, layers 760a and 760b are formed from a low index material (i.e., a material having a lower index of refraction than the material forming the immediately adjacent ones of the waveguides 670, 680, 690). Preferably, the index of refraction of the material forming layers 760a, 760b is 0.05 or more, or 0.10 or less, relative to the index of refraction of the material forming the waveguides 670, 680, 690. Advantageously, the lower refractive index layers 760a, 760b may act as cladding layers to promote total internal reflection (TIR) ​​of light through the waveguides 670, 680, 690 (e.g., TIR between the top and bottom major surfaces of each waveguide). In some embodiments, the layers 760a, 760b are formed from air. Although not shown, it should be understood that the top and bottom of the illustrated set of waveguides 660 may include immediately adjacent cladding layers.

[0112] Preferably, for ease of manufacturing and other considerations, the materials forming the waveguides 670, 680, 690 are similar or the same, and the materials forming the layers 760a, 760b are similar or the same. In some embodiments, the materials forming the waveguides 670, 680, 690 may vary between one or more of the waveguides, and / or the materials forming the layers 760a, 760b may differ while still maintaining the various refractive index relationships described above.

[0113] 9A , light rays 770, 780, 790 are incident on the set of waveguides 660. It should be understood that light rays 770, 780, 790 may be launched into the waveguides 670, 680, 690 by one or more image launch devices 360, 370, 380, 390, 400 ( FIG. 6 ). Light rays 770, 780, 790 may constitute image light, i.e., light encoded with image information. For example, the light may be spatially modulated or otherwise provided with different intensities and / or different wavelengths at different locations, e.g., to form pixels that form an image.

[0114] In some embodiments, the light beams 770, 780, 790 have different properties, e.g., different wavelengths or different wavelength ranges, that may correspond to different colors. Each of the incoupling optical elements 700, 710, 720 deflects the incident light such that the light propagates through a respective one of the waveguides 670, 680, 690 by TIR. In some embodiments, each of the incoupling optical elements 700, 710, 720 selectively deflects one or more particular wavelengths of light while transmitting other wavelengths to the underlying waveguide and associated incoupling optical element.

[0115] For example, incoupling optical element 700 may be configured to deflect light beam 770 having a first wavelength or wavelength range while transmitting light beams 780 and 790 having different second and third wavelengths or wavelength ranges, respectively. The transmitted light beam 780 impinges on and is deflected by incoupling optical element 710, which is configured to deflect light of the second wavelength or wavelength range. Light beam 790 is deflected by incoupling optical element 720, which is configured to selectively deflect light of the third wavelength or wavelength range.

[0116] 9A, the deflected light rays 770, 780, 790 are deflected to propagate through the corresponding waveguides 670, 680, 690. That is, the incoupling optical element 700, 710, 720 of each waveguide deflects the light into its corresponding waveguide 670, 680, 690 and incouplings the light into its corresponding waveguide. The light rays 770, 780, 790 are deflected at an angle that causes the light to propagate through the respective waveguides 670, 680, 690 by TIR. The light rays 770, 780, 790 propagate through the respective waveguides 670, 680, 690 by TIR until they strike the corresponding optical dispersive element 730, 740, 750 of the waveguide.

[0117]

[0046] Referring now to Figure 9B, a perspective view of the multiple stacked waveguide embodiment of Figure 9A is illustrated. As described above, the in-coupled light rays 770, 780, 790 are deflected by the in-coupling optical elements 700, 710, 720, respectively, and then propagate by TIR within the waveguides 670, 680, 690, respectively. The light rays 770, 780, 790 then impinge on the optically dispersive elements 730, 740, 750, respectively. The optically dispersive elements 730, 740, 750 deflect the light rays 770, 780, 790 to propagate towards the out-coupling optical elements 800, 810, 820, respectively.

[0118] In some embodiments, the optically dispersive elements 730, 740, 750 are orthogonal pupil expanders (OPEs). In some embodiments, the OPEs deflect or disperse the light to the out-coupling optical elements 800, 810, 820, and in some embodiments may also increase the beam or spot size of this light as it propagates to the out-coupling optical elements. In some embodiments, the optically dispersive elements 730, 740, 750 may be omitted and the in-coupling optical elements 700, 710, 720 may be configured to deflect the light directly to the out-coupling optical elements 800, 810, 820. For example, referring to FIG. 9A, the optically dispersive elements 730, 740, 750 may be replaced with the out-coupling optical elements 800, 810, 820, respectively. In some embodiments, the outcoupling optical element 800, 810, 820 is an exit pupil (EP) or exit pupil expander (EPE) that directs light to the viewer's eye 210 (FIG. 7). It should be understood that an OPE may be configured to increase the size of the eyebox in at least one axis, and an EPE may increase the eyebox in an axis that intersects, e.g., perpendicular to, the axis of the OPE. For example, each OPE may be configured to redirect a portion of the light striking the OPE to an EPE of the same waveguide, while allowing the remaining portion of the light to continue propagating down the waveguide. In response to striking the OPE again, another portion of the remaining light is redirected to the EPE, which continues to propagate further down the waveguide, and so on. Similarly, in response to striking the EPE, a portion of the impinging 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 strikes the EP again, at which point another portion of the impinging light is directed out of the waveguide, and so on. As a result, a single beam of internally coupled light may be "replicated" each time a portion of that light is redirected by an OPE or EPE, thereby forming a cloned beam field of light, as shown in Figure 6. In some embodiments, the OPE and / or EPE may be configured to modify the size of the beam of light.

[0119] Thus, referring to Figures 9A and 9B, in some embodiments, a set of waveguides 660 includes, for each primary color, a waveguide 670, 680, 690, an in-coupling optical element 700, 710, 720, an optical dispersion element (e.g., OPE) 730, 740, 750, and an out-coupling optical element (e.g., EP) 800, 810, 820. The waveguides 670, 680, 690 may be stacked with an air gap / cladding layer between each one. The in-coupling optical element 700, 710, 720 redirects or deflects the incoming light into its waveguide (with different in-coupling optical elements receiving different wavelengths of light). The light then propagates at an angle that will result in TIR within the individual waveguides 670, 680, 690. In the illustrated embodiment, light ray 770 (e.g., blue light) is deflected by the first in-coupling optical element 700 in the manner described above, then continues bouncing back down the waveguide, interacting with the optically dispersive element (e.g., OPE) 730 and then the out-coupling optical element (e.g., EP) 800. Light rays 780 and 790 (e.g., green and red light, respectively) pass through the waveguide 670, where light ray 780 impinges on and is deflected by the in-coupling optical element 710. Light ray 780 then proceeds via TIR back down the waveguide 680, to its optically dispersive element (e.g., OPE) 740 and then the out-coupling optical element (e.g., EP) 810. Finally, light ray 790 (e.g., red light) passes through the waveguide 690 and impinges on the optically in-coupling optical element 720 of the waveguide 690. The light in-coupling optical element 720 deflects the light beam 790 such that it propagates by TIR to a light dispersive element (e.g., OPE) 750 and then by TIR to an out-coupling optical element (e.g., EP) 820. The out-coupling optical element 820 then finally out-couples the light beam 790 to a viewer which also receives the out-coupled light from the other waveguides 670, 680.

[0120] FIG. 9C illustrates a top-down plan view of an example of the multiple stacked waveguides of FIGS. 9A and 9B. As shown, the waveguides 670, 680, 690 may be vertically aligned with each waveguide's associated light dispersive element 730, 740, 750 and associated out-coupling optical elements 800, 810, 820. However, as discussed herein, the in-coupling optical elements 700, 710, 720 are not vertically aligned. Rather, the in-coupling optical elements are preferably non-overlapping (e.g., laterally spaced apart when viewed in a top-down view). As discussed further herein, this non-overlapping spatial arrangement facilitates the injection of light from different sources into different waveguides on a one-to-one basis, thereby allowing a specific light source to be uniquely coupled to a specific waveguide. In some embodiments, an arrangement including non-overlapping, spatially separated in-coupling optical elements may be referred to as a shifted or split-pupil system, and the in-coupling optical elements in these arrangements may correspond to sub-pupils.

[0121] Some embodiments of the wearable display system 60 (FIG. 2) may include a display 70 that comprises a split-pupil waveguide assembly. For example, various embodiments of the waveguide assembly 260 or 660 (FIGS. 6 and 9A-9C) may be configured as a split-pupil waveguide assembly. As an example, a split-pupil waveguide assembly may comprise six waveguides, each associated with an internal coupling optical element configured to receive light output from a projector and internally couple light having specific optical properties (e.g., a particular wavelength, range of wavelengths, and / or a particular polarization state) into the waveguide. A first set of three waveguides may be configured to receive red, green, and blue light that generates red, green, and blue images at a first depth plane, and a second set of three waveguides may be configured to receive red, green, and blue light that generates red, green, and blue images at a second depth plane. It should be understood that more or fewer primary colors are possible and the number of depth planes may also be varied as desired.

[0122] A projector associated with such a display system may be configured to output light from a plurality of spatially separated pupils that are directed toward a split-pupil waveguide assembly. For example, in some embodiments, a projector associated with a display that includes a split-pupil waveguide assembly may include six spatially separated exit pupils (also referred to herein simply as pupils, where the identification of the pupils as exit pupils is clear from the context). As an example, a first set of three spatially separated pupils may be configured to output red, green, and blue images for a first depth plane, and a second set of three spatially separated pupils may be configured to output red, green, and blue images for a second depth plane. Light from each of the six spatially separated pupils is internally coupled into a corresponding one of the waveguides of the waveguide assembly. As another example, in some embodiments, a projector associated with a display that includes a split-pupil waveguide assembly may include two spatially separated pupils. The first spatially separated pupil is configured to output red, green, and blue images for the first depth plane, and the second spatially separated pupil is configured to output red, green, and blue images for the second depth plane. Light from the first spatially separated pupil is internally coupled into corresponding ones of a first set of waveguides (e.g., three waveguides, one for each primary color) associated with the first depth plane, and light from the second spatially separated pupil is internally coupled into corresponding ones of a second set of waveguides (e.g., three waveguides, one for each primary color) associated with the second depth plane.

[0123] In some embodiments, the internal coupling optical element may be a diffraction grating. For example, the internal coupling optical element may comprise a blazed grating. In various embodiments, a high refractive index dielectric material may be disposed over the blazed grating. Each of the constituent waveguides of the split-pupil waveguide assembly may comprise an internal coupling grating (ICG) that is spatially aligned with one of a plurality of spatially separated pupils of the projector. For example, a waveguide configured to generate a red image in a first depth plane may comprise an internal coupling grating (ICG) that is positioned relative to a corresponding pupil of the projector that is configured to output the red image in the first depth plane. As another example, a waveguide configured to generate a green image in a second depth plane may comprise an internal coupling grating (ICG) that is positioned relative to a corresponding pupil of the projector that is configured to output the green image in the second depth plane.

[0124] Thus, various embodiments of the display system may include a plurality of waveguides, each waveguide including an incoupling grating configured to receive light output from a corresponding pupil of the projector and incoupling into the waveguide. In such embodiments, the number of pupils through which light is output from the projector may be equal to the number of waveguides in the plurality of waveguides or equal to the number of depth planes. Incoupling optical elements associated with each waveguide may be configured to promote high incoupling efficiency of light of a desired color into that waveguide.

[0125] As discussed above, the size of the projector may depend on the number of pupils that the projector outputs. For example, the size of the projector may be reduced if the number of pupils that the projector outputs light to is reduced. Without being bound to any particular theory, the overall size of the display system may also be reduced if the number of pupils that the projector outputs light to is reduced. For example, to reduce the size of the projector, the projector may be configured to output two different color images (e.g., a blue image and a red image) in terms of the depth plane from a first pupil, while a third different color image (e.g., a green image) in terms of the depth plane may be output from a second pupil that is spatially separated from the first pupil. Preferably, the colors that share a common pupil are selected to provide the greatest difference in wavelength (e.g., in a set of primary color images) to aid in the differentiation of the internally combined optical element between the different primary colors. As another example, to reduce the size of the projector, the projector may be configured to output three different color images (e.g., a blue image, a red image, and a green image) in relation to the depth plane from a single pupil, as discussed above.

[0126] Thus, to reduce the size of the projector and / or the overall size of the display system, the number of pupils to which the projector outputs light may be less than the number of waveguides in the multiple waveguides. In an embodiment of a display system with a projector that outputs different color images (e.g., two or three color images) with respect to the depth plane from a single pupil, the in-coupling optical elements associated with the waveguides that receive the different color images output from the single pupil of the projector are aligned (e.g., vertically aligned) to appear spatially overlapping when viewed in a top-down view. Waveguide architectures are discussed herein in which the in-coupling optical elements are vertically aligned to receive different color images (e.g., two or three color images) from the single pupil of the projector. In addition, methods and systems configured to reduce or prevent unintended in-coupling of color images into the waveguides are also described herein.

[0127] FIG. 10 diagrammatically illustrates a perspective view of an example of a split-pupil waveguide assembly comprising multiple waveguides stacked over one another. Each waveguide in the multiple waveguides is associated with an internal coupling optical element configured to internally couple light having specific optical properties (e.g., a particular wavelength, range of wavelengths, and / or a particular polarization state). The illustrated embodiment comprises three waveguides 670, 680, and 690 stacked over one another. Each waveguide is associated with an internal coupling optical element (e.g., internal coupling optical elements 700, 710, and 720) configured to internally couple light having different wavelengths output from the projector. The projector may be configured to output multiple different color images (e.g., blue and red images) from a first pupil, one or more different color images (e.g., green images) from a second pupil that is spatially separated from the first pupil. Thus, in the embodiment illustrated in FIG. 10, the internal coupling optical elements 700 and 720 spatially overlap each other laterally (e.g., in the xz plane) and are vertically aligned with each other (e.g., along the y-axis) to coincide with the first pupil of the projector, while the internal coupling optical element 710 is displaced laterally (e.g., in the xz plane) from the internal coupling optical elements 700 and 720 to coincide with the second pupil of the projector.

[0128] FIG. 10A illustrates a side view of the waveguide assembly illustrated in FIG. 10 along the plane 10A-10A. As discussed above, the projector is configured to output a first and a second color image (e.g., red and blue images) through a first pupil and a third color image (e.g., green image) through a second pupil. In FIG. 10A, light rays 1005 and 1007 represent the first and second color images output from the first pupil, and light ray 1009 represents the third color image output from the second pupil. With reference to FIG. 10A, the incoupling optical element 700 is configured to incoupling the first color image (represented by light ray 1005) into the waveguide 670 for propagation through the waveguide 670 by multiple total internal reflections at the major surfaces of the waveguide 670. In FIG. 10A, light ray 1005r represents the propagation of the incoupling light corresponding to the first color image. The incoupling optical element 720 is configured to incoupling a second color image (represented by light ray 1007) into the waveguide 690 for propagation through the waveguide 690 by multiple total internal reflections at a major surface of the waveguide 690. In FIG. 10A, light ray 1007r represents propagation of the incoupling light corresponding to the second color image. As discussed above, the incoupling optical element 700 associated with the waveguide 670 and the incoupling optical element 720 associated with the waveguide 690 are vertically aligned with each other (e.g., along the y-axis) and spatially overlap each other laterally (e.g., in the xz plane).

[0129] In FIG. 10A, the incoupling optical element 710 is configured to incoupling the third color image (represented by light ray 1009) into the waveguide 680 for propagation through the waveguide 680 by multiple total internal reflections at the major surfaces of the waveguide 680. In FIG. 10A, light ray 1009r represents the propagation of the incoupling light corresponding to the third color image. The incoupling optical element 710 is positioned to receive light output from a second pupil of the projector, which is spatially separated from the first pupil. Thus, the incoupling optical element 710 is laterally spaced apart from the incoupling optical elements 700 and 720 when viewed in a top-down view.

[0130] As discussed above, the incoupling optical elements 700, 710, and 720 are configured to redirect incident light having specific optical characteristics (e.g., a particular wavelength, range of wavelengths, and / or a particular polarization state) to be incoupling into the associated waveguide. For example, in various embodiments, the incoupling optical elements 700, 710, and 720 may comprise refractive, reflective, and / or diffractive features configured to selectively refract, reflect, and / or diffract light having a particular color (e.g., red, green, or blue) such that a majority of the incident light having a particular color or wavelength is incoupling into the associated waveguide. In such embodiments, a majority of the incident light having a color that is not configured to be selectively refracted, reflected, and / or diffracted by the incoupling optical elements 700, 710, and 720 passes through the incoupling optical elements 700, 710, and 720 without being incoupling into the associated waveguide. In various embodiments, the internal coupling optical elements 700, 710, and 720 may comprise wavelength-selective and / or polarization-selective gratings. In embodiments of the internal coupling optical elements 700, 710, and 720 that comprise polarization-selective gratings, the light output from the first pupil corresponding to the first color image may have a first polarization state (e.g., a linear, circular, or elliptical polarization state) and the light output from the first pupil corresponding to the first color image may have a second polarization state (e.g., a linear, circular, or elliptical polarization state) that is different from the first polarization state. In embodiments of the internal coupling optical elements 700, 710, and 720 that comprise wavelength-selective gratings, the light output from the first pupil corresponding to the first color image and the light output from the first pupil corresponding to the second color image may have the same polarization state. Without any loss of generality, in embodiments of the incoupling optical elements 700, 710, and 720 that comprise wavelength-selective gratings, the gratings may be configured such that the coupling efficiency of the gratings to light having a particular wavelength exceeds the coupling efficiency of the gratings to light having a wavelength other than the particular wavelength. In such embodiments, the coupling efficiency of the gratings to light having a wavelength other than the particular color may be reduced, although in practice a small amount of light having a wavelength other than the particular color may be incoupling into the associated waveguide.It should be understood that different wavelengths of light may correspond to different colors, and thus references herein to different colors of light should be understood to also be references to different wavelengths of light.

[0131] 10A, light rays 1007 forming a second color image output from the first pupil of the projector are depicted as passing through the incoupling optical element 700 without being incoupling into the waveguide 670. Although FIG. 10A depicts all incident light corresponding to the first color image output from the first pupil of the projector being incoupling into the waveguide 670, in practice, a portion of the incident light corresponding to the first color image output from the first pupil of the projector may be transmitted through the incoupling optical element 700 and may not be incoupling into the waveguide 670. Similarly, although FIG. 10A depicts all incident light corresponding to the second color image output from the first pupil of the projector being transmitted through the incoupling optical element 700 without being redirected, in practice, a portion of the incident light corresponding to the second color image output from the first pupil of the projector may be incoupling into the waveguide 670 by the incoupling optical element 700. In the embodiment depicted in Figure 10A, the incoupling optical elements 700, 710, and 720 are disposed across a major surface (e.g., bottom major surface) of the waveguide that is opposite a major surface (e.g., top major surface) that receives incident light from a projector. Thus, the incoupling optical elements 700, 710, and 720 are configured to operate in a reflective mode. However, in other embodiments, the incoupling optical elements 700, 710, and 720 may be disposed on a major surface (e.g., top major surface) that receives incident light from a projector and configured to operate in a transmissive mode.

[0132] 10A, the incoupling optical elements 700, 710, and 720 are illustrated as being disposed on or adjacent to the bottom major surface. Thus, the incoupling optical elements 700, 710, and 720 are configured to operate in a reflective mode. For example, one or more of the incoupling optical elements 700, 710, and 720 may comprise a reflective grating for selectively incoupling light of specific wavelengths into respective ones of the waveguides 670, 680, and 690. For example, in the embodiment illustrated in FIG. 10A , internal coupling optical element 700 is configured to reflect light (represented by light ray 1005) that forms a first color image into waveguide 670 to propagate through waveguide 670 by multiple total internal reflections, internal coupling optical element 710 is configured to reflect light (represented by light ray 1009) that forms a third color image into waveguide 680 to propagate through waveguide 680 by multiple total internal reflections, and internal coupling optical element 720 is configured to reflect light (represented by light ray 1007) that forms a second color image into waveguide 690 to propagate through waveguide 690 by multiple total internal reflections.

[0133] 10A, the incoupling optical element 700 is also configured to pass a majority of the incident light (represented by light rays 1007) that forms the second color image. For example, the incoupling optical element 700 can be configured to pass greater than 50% of the incident light (represented by light rays 1007) that forms the second color image. As another example, the internal coupling optical element 700 can be configured to pass greater than or equal to approximately 60% of the incident light (represented by light ray 1007) that forms the second color image, greater than or equal to approximately 75% of the incident light (represented by light ray 1007) that forms the second color image, greater than or equal to approximately 80% of the incident light (represented by light ray 1007) that forms the second color image, greater than or equal to approximately 85% of the incident light (represented by light ray 1007) that forms the second color image, greater than or equal to approximately 90% of the incident light (represented by light ray 1007) that forms the second color image, or greater than or equal to approximately 95% of the incident light (represented by light ray 1007) that forms the second color image.

[0134] In various embodiments, one or more of the incoupling optical elements 700, 710, and 720 can be configured to transmit a majority of incident light (e.g., greater than or equal to about 50%, greater than or equal to about 60%, greater than or equal to about 70%, greater than or equal to about 80%, greater than or equal to about 90%, greater than or equal to about 95%, or greater than or equal to about 99%) having wavelengths that are not intended to be incoupling by the individual incoupling optical element into the associated waveguide, while simultaneously reflecting a majority of incident light (e.g., greater than or equal to about 50%, greater than or equal to about 60%, greater than or equal to about 70%, greater than or equal to about 80%, greater than or equal to about 90%, greater than or equal to about 95%, or greater than or equal to about 99%) having wavelengths that are intended to be incoupling by the individual incoupling optical element into the associated waveguide.

[0135] In various embodiments, the incoupling optical element associated with the last waveguide in the stack (e.g., incoupling optical element 720 associated with waveguide 690) can be metalized. Additionally, in some embodiments having two pupils, the incoupling optical element for the last waveguide of each pupil may be metalized. It should be understood that the last waveguide is the waveguide that last receives light after the light has passed through all other waveguides. In a two-pupil arrangement, each pupil may have a last waveguide, for example, the last waveguide for the pupil of ray 1009 is waveguide 680. Additionally, the last pupil for the pupil of ray 1007 is waveguide 690. As a result, in some embodiments, one or both of the incoupling optical elements 710 and 720 may be metalized. The metalization may increase the efficiency of reflection and therefore the light incoupling efficiency. However, a metallized reflective grating may reduce the transmission of light having wavelengths that are not intended to be incoupled by a separate incoupling optical element into the associated waveguide, and therefore the incoupling optical elements for waveguides that receive light from the projector before the last waveguide are preferably not metallized.

[0136] In various embodiments, one or more of the internal coupling optical elements 700, 710, and 720 may comprise a transmissive diffraction grating configured to redirect a majority of incident light (e.g., greater than or equal to about 50%, greater than or equal to about 60%, greater than or equal to about 70%, greater than or equal to about 80%, greater than or equal to about 90%, greater than or equal to about 95%, or greater than or equal to about 99%) having a wavelength intended to be internally coupled by the respective internal coupling optical element into the associated waveguide at an angle at which the redirected light would be propagated through the associated waveguide by total internal reflection. At the same time, one or more of the incoupling optical elements 700, 710, and 720 with a transmissive grating are configured to transmit a majority of incident light (e.g., greater than or equal to about 50%, greater than or equal to about 60%, greater than or equal to about 70%, greater than or equal to about 80%, greater than or equal to about 90%, greater than or equal to about 95%, or greater than or equal to about 99%) having wavelengths not intended to be incoupling by the respective incoupling optical element into the associated waveguide. In such an embodiment, one or more of the incoupling optical elements 700, 710, and 720 with a transmissive grating are disposed on an upper major surface of the waveguide.

[0137] FIG. 11 diagrammatically illustrates a perspective view of an example of a waveguide assembly comprising multiple waveguides stacked over one another. Each waveguide in the multiple waveguides is associated with an in-coupling optical element configured to in-couple light having specific optical properties (e.g., a particular wavelength, range of wavelengths, and / or a particular polarization state). The illustrated embodiment comprises three waveguides 670, 680, and 690 stacked over one another. Each waveguide is associated with an in-coupling optical element (e.g., in-coupling optical elements 700, 710, and 720) configured to in-couple light having different wavelengths that are output from the projector. The projector may be configured to have a single pupil, from which multiple different color images (e.g., blue, green, and red images) are output. Thus, in the embodiment illustrated in FIG. 11, the internal coupling optical elements 700, 710, and 720 spatially overlap one another laterally (e.g., in the xz plane) and are vertically aligned with one another (e.g., along the y-axis) to coincide with the projector's single pupil.

[0138] FIG 11A illustrates a side view of the waveguide assembly illustrated in FIG 11 along axis 11A-11A. As discussed above, the projector is configured to output a first color image, a second color image, and a third color image (e.g., red, green, and blue color images) through a single pupil. In FIG 11A, light rays 1005, 1007, and 1009 represent the first, second, and third color images output from the single pupil. Referring to FIG. 11A , internal coupling optical element 700 is configured to internally couple a first color image (represented by light ray 1005) into waveguide 670 to propagate through waveguide 670 by multiple total internal reflections at the top and bottom major surfaces of waveguide 670, internal coupling optical element 720 is configured to internally couple a second color image (represented by light ray 1007) into waveguide 690 to propagate through waveguide 670 by multiple total internal reflections at the top and bottom major surfaces of waveguide 670, and internal coupling optical element 710 is configured to internally couple a third color image (represented by light ray 1009) into waveguide 680 to propagate through waveguide 670 by multiple total internal reflections at the top and bottom major surfaces of waveguide 670. As discussed above, the in-coupling optical element 700 is configured to in-couple a majority of the incident light corresponding to the first color image and allow a majority of the incident light corresponding to the second and third color images to pass through without being redirected. Similarly, the in-coupling optical element 710 is configured to in-couple a majority of the incident light corresponding to the third color image and allow a majority of the incident light corresponding to the second color image to pass through without being redirected.

[0139] In the above embodiment, it is desirable for the incoupling optical element 700 to incoupling all (or a majority of) the incident light corresponding to the first color image into the associated waveguide 670, while allowing all (or a majority of) the incident light corresponding to the second and third color images to be transmitted without being incoupling. Similarly, it is desirable for the incoupling optical element 710 to incoupling all (or a majority of) the incident light corresponding to the third color image into the associated waveguide 680, while allowing all (or a majority of) the incident light corresponding to the second color image to be transmitted without being incoupling. However, in practice, a portion of the incident light corresponding to the second and third color images may be incoupling into the associated waveguide 670 by the incoupling optical element 700, and a portion of the incident light corresponding to the second and third color images may be incoupling into the associated waveguide 680 by the incoupling optical element 710. Additionally, a portion of the incident light corresponding to the first color image may be transmitted through incoupling optical element 700 and incoupling into waveguides 680 and / or 690 .

[0140] Incoupling of color images into unintended waveguides may cause undesirable optical effects such as, for example, crosstalk and / or afterimages. For example, incoupling of a first color image into unintended waveguides 680 and / or 690 may result in undesirable crosstalk between the first color image, the second color image, and / or the third color image, and / or cause undesirable afterimages. As another example, incoupling of a second or third color image into unintended waveguide 670 may result in undesirable crosstalk between the first color image, the second color image, and / or the third color image, and / or cause undesirable afterimages. These undesirable optical effects may be mitigated by providing an optical device (e.g., an absorptive filter) that may reduce the amount of incident light incoupling into the unintended waveguides.

[0141] 12, 12A, 13, and 13A illustrate implementations of a waveguide assembly with one or more optical filters. FIG. 12 and FIG. 12A respectively illustrate perspective and side views of a waveguide assembly with three waveguides 670, 680, and 690 stacked over one another configured to receive light corresponding to a first color image and a second color image from a first pupil of a projector and a third color image from a second pupil of the projector that is spatially separated from the first pupil. In FIG. 12A, light corresponding to the first color image, represented by light ray 1005, is intended to be incoupling into the waveguide 670 by the incoupling optical element 700, and light corresponding to the second color image, represented by light ray 1007, is intended to be incoupling into the waveguide 690 by the incoupling optical element 720. The waveguide assembly illustrated in FIG. 12A comprises a plurality of optical filters 1101 and 1103 configured to reduce an amount of incident light corresponding to a second color image (represented by light ray 1007) incoupling into the waveguide 670 and to reduce an amount of incident light corresponding to a first color image (represented by light ray 1005) incoupling into the waveguide 690. The plurality of optical filters 1101 disposed on the top and bottom major surfaces of the waveguide 670 are configured to absorb light corresponding to the second color image (e.g., red) incoupling into the waveguide 670. The plurality of optical filters 1101 may be configured as an absorptive filter that absorbs the incoupling light corresponding to the second color image (e.g., red) propagating through the waveguide 670 by total internal reflection. The plurality of optical filters 1101 may be configured to not affect the propagation of the incoupling light corresponding to the first color propagating through the waveguide 670 via TIR. Thus, the plurality of optical filters 1101 may be configured to be substantially transmissive to the incoupled light corresponding to a first color that propagates via TIR through the waveguide 670. Thus, the plurality of optical filters 1101 may be considered a selectively transparent optical component that is substantially transmissive to light of a certain color.

[0142] Another optical filter 1103 may be disposed between the waveguides 670 and 690, configured to absorb incident light corresponding to the first color image that is not incoupled into the waveguide and transmitted through the incoupling optical element 700. The optical filter 1103 may be substantially transmissive to light of the second and third colors such that incident light corresponding to the second and / or third color images is transmitted through the optical filter 1103 with little or no attenuation. Thus, the optical filter 1103 may be considered a selectively transparent optical component that is substantially transmissive to light of the second and third colors. The optical filter 1103 may be disposed on a major surface. In some embodiments, the optical filter 1103 may be disposed on the upper major surface of the waveguide 680, as shown in FIG. 12A. For example, the optical filter 1103 may be disposed on a portion of the upper major surface of the waveguide 680 that is laterally spaced from the incoupling optical element 710 and vertically aligned with the first pupil of the projector. In some embodiments, the optical filter 1103 may be disposed on a bottom major surface of the waveguide 680 or on an upper major surface of the waveguide 690. For example, the optical filter may be disposed on an upper major surface of the waveguide 690, which is configured to receive incident light corresponding to the second color image. In some other embodiments, the optical filter 1103 may be disposed on a separate substrate disposed between the waveguides 670 and 690.

[0143] 12A , the optical filter 1101 may be disposed over a portion of the top and / or bottom major surface of the waveguide 670. For example, the optical filter 1101 may be disposed over a portion of the top major surface of the waveguide 670 that is spaced laterally from the incoupling optical element 700. In some embodiments, the optical filter 1101 may have a single-pass attenuation coefficient of less than or equal to about 10% (e.g., less than or equal to about 50%, greater than or equal to about 60%, greater than or equal to about 70%, greater than or equal to about 80%, greater than or equal to about 90%, greater than or equal to about 95%) of the second color of light that has not propagated via TIR in the waveguide 670 and that is incident on the optical filter 1101 from the surroundings is transmitted through the optical filter 1101. Some such embodiments of optical filter 1101 having a single pass attenuation coefficient of less than or equal to about 10% (e.g., less than or equal to about 5%, less than or equal to about 2%, less than or equal to about 1%) may be disposed over a majority of the area of ​​the upper major surface of waveguide 670 (e.g., the surface that receives the incident light from the projector) without significantly reducing the amount of incident light of the first color image that is coupled in-coupling into waveguide 670. Waveguide assemblies comprising some such embodiments of optical filter 1101 having a single pass attenuation coefficient of less than or equal to about 10% may also be incorporated into wearable display system 60 described above to allow a majority of the light originating from world 510 to be transmitted to the user. Thus, embodiments of optical filter 1101 having a single pass attenuation coefficient of less than or equal to about 10% may be disposed within the field of view of the user. Some other embodiments of optical filter 1101 may have a high single pass attenuation coefficient. Such an embodiment of the optical filter 1101 may be placed in a portion of the waveguide 670 that is outside the user's field of view.

[0144] 12A, the optical filter 1103 may be configured to have a high single-pass attenuation coefficient for light having a first color and a low single-pass attenuation coefficient for light having a second color. For example, the optical filter 1103 may be configured to transmit greater than about 90% of the incident light having the second color (e.g., red) and absorb greater than about 90% of the incident light having the first color (e.g., blue).

[0145] 13 and 13A respectively illustrate perspective and side views of a waveguide assembly comprising three waveguides 670, 680, and 690 stacked over one another configured to receive light corresponding to a first color image, light corresponding to a second color image, and light corresponding to a third color image from a single pupil of a projector. The waveguide assembly illustrated in FIG. 13A comprises a number of optical filters 1105, 1107, and 1109 configured to reduce the amount of incident light corresponding to the second and third color images (represented by light rays 1007 and 1009) that is internally coupled into or propagating within waveguide 670, to reduce the amount of incident light corresponding to the first and second color images (represented by light rays 1005 and 1007) that is internally coupled into or propagating within waveguide 680, and to reduce the amount of incident light corresponding to the first and third color images (represented by light rays 1005 and 1009) that is internally coupled into waveguide 690.

[0146] For example, a plurality of optical filters 1105 disposed on the top and bottom major surfaces of the waveguide 670 are configured to absorb light corresponding to the second and third color images (e.g., red and green) that are incoupling into the waveguide 670. An optical filter 1107 disposed between the waveguides 670 and 680 is configured to absorb a majority (e.g., greater than or equal to about 90%, greater than or equal to about 95%, or greater than or equal to about 99%) of the light corresponding to the first color image (e.g., blue image) that is transmitted through the incoupling optical element 700. A plurality of optical filters 1109 disposed on the top and bottom major surfaces of the waveguide 680 are configured to absorb light corresponding to the second color image (e.g., red) and light corresponding to the first color image (e.g., blue) that is incoupling into the waveguide 680. An optical filter 1111 disposed between waveguides 680 and 690 is configured to absorb a portion of the light corresponding to a third color image (eg, a green image) that is transmitted through the internal coupling optical element 710.

[0147] As discussed above, the plurality of optical filters 1105 may be configured as absorptive filters that absorb the incoupled light corresponding to the second and third color images (e.g., red and green) that propagate through the waveguide 670 by total internal reflection without affecting the propagation of the incoupled light corresponding to the first color that propagates via TIR through the waveguide 670. Similarly, the plurality of optical filters 1109 may be configured as absorptive filters that absorb the incoupled light corresponding to the second color image (e.g., red) that propagates through the waveguide 680 by total internal reflection without affecting the propagation of the incoupled light corresponding to the third color that propagates via TIR through the waveguide 680.

[0148] The optical filters 1107 and 1111 may also be configured as absorbing filters. The optical filter 1107 may be substantially transmissive to light of the second and third colors such that incident light corresponding to the second and / or third color images is transmitted through the optical filter 1107 with little or no attenuation. The optical filter 1111 may be substantially transmissive to light of the second color such that incident light corresponding to the second color image is transmitted through the optical filter 11111 with little or no attenuation. Thus, the optical filters 1107 and 1111 may be considered as selectively transparent optical components that are transmissive to light of a certain color. The optical filter 1107 may be disposed on a major surface (e.g., the top major surface) of the waveguide 680 as shown in FIG. 13A. Alternatively, the optical filter 1107 may be disposed on a separate substrate that is positioned between the waveguides 670 and 680 or on the bottom major surface of the waveguide 670. Optical filter 1111 may be disposed on a major surface (e.g., the top major surface) of waveguide 690. Alternatively, optical filter 1111 may be disposed on a separate substrate positioned between waveguides 680 and 690 or on a bottom major surface of waveguide 680. Without any loss of generality, optical filters 1107 and 1111 may be vertically aligned with a single pupil of a projector that outputs light corresponding to the first, second, and third color images.

[0149] Various embodiments of optical filters 1105 and 1109 may have a single-pass attenuation coefficient of less than about 10%. Various embodiments of optical filters 1107 and 1111 may be configured to have a low attenuation coefficient for wavelengths to be transmitted and a high attenuation coefficient for wavelengths to be absorbed. For example, optical filter 1107 may be configured to transmit greater than about 90% of incident light having a second and third color (e.g., red and green) and absorb greater than 90% of incident light having a first color (e.g., blue). Similarly, optical filter 1111 may be configured to transmit greater than about 90% of incident light having a second color (e.g., red) and absorb greater than 90% of incident light having a third color (e.g., green). The optical filters 1101, 1103, 1105, 1107, 1109, and 1111 described above may comprise a layer of color-selective absorbing material deposited on a substrate (e.g., a glass substrate, a polymer substrate, a crystalline substrate, one or both surfaces of the waveguides 670, 680, and / or 690, etc.). The color-selective absorbing material may include a dye, ink, or other light absorbing material.

[0150] The color selective absorbing material may be deposited on the substrate using various deposition methods. For example, the color selective absorbing material may be deposited on the substrate using a jet deposition technique (e.g., inkjet deposition). Inkjet deposition may facilitate depositing a thin layer of color selective absorbing material. Using inkjet deposition, the thickness of the layer of color selective absorbing material may be controlled. For example, a layer of color selective absorbing material deposited using inkjet deposition may have a thickness of about 10 nm to about 1 micron (e.g., about 10 nm to about 50 nm, about 25 nm to about 75 nm, about 40 nm to about 100 nm, about 80 nm to about 300 nm, about 200 nm to about 500 nm, about 400 nm to about 800 nm, about 500 nm to about 1 micron, or any value within a range / subrange defined by these values). Controlling the thickness of the deposited layer of color selective absorbing material may be advantageous in achieving an optical filter having a desired attenuation coefficient. Additionally, inkjet deposition may facilitate deposition of a layer of color selective absorbing material having a uniform thickness. Inkjet deposition may also advantageously reduce the amount of color-selective absorbing material wasted during deposition. In addition, different compositions of color-selective absorbing material may be deposited in different parts of the substrate using inkjet deposition. Furthermore, layers having different thicknesses may be deposited in different parts of the substrate. Such variation in composition and / or thickness may advantageously allow for location variation in absorption. For example, in areas of the waveguide where transmission of light from the surroundings is not necessary (to allow the viewer to see the surrounding environment), the composition and / or thickness may be selected to provide high absorption or attenuation of light. Other deposition methods, such as coating, spin-coating, spraying, etc., may also be employed to deposit color-selective absorbing material on the substrate.

[0151] The size (e.g., shape and area) of the light beam to be absorbed by the corresponding optical filter is preferably substantially equal to the size of the optical filters 1103, 1107, and 1111 described above (FIGS. 12A, 13A, and 13A, respectively). For example, the size of the optical filter 1103 and the light beam 1005 are preferably substantially equal, with the light beam 1005 forming a first color image configured to be absorbed by the optical filter 1103. Similarly, the size of the optical filter 1107 and the light beam 1005 forming the first color image configured to be absorbed by the optical filter 1107, and the size of the optical filter 1111 may be equal to the size of the light beam 1009 forming the third color image configured to be absorbed by the optical filter 1111. Without any loss of generality, in an embodiment of the display device in which the size of the optical filter is comparable to the size of the incident light beam configured to be absorbed, the optical filter can be vertically aligned with the exit pupil of the projector that emits the incident light beam configured to be absorbed.

[0152] However, in various embodiments, it may not be practical to manufacture optical filters having a size equal to the size of the light beam to be absorbed. In some such embodiments, the size of the optical filters 1103, 1107, and 1111 can be configured to be smaller than the size of the corresponding light beam to be absorbed. In some such embodiments with optical filters having a size smaller than the size of the corresponding light beam to be absorbed, the position of the optical filter can be displaced laterally with respect to the exit pupil of the projector emitting the incident light beam configured to be absorbed such that those angles of incidence that contribute more to degradation of image quality are absorbed compared to other angles of incidence.

[0153] In the embodiments illustrated in Figures 12, 12A, 13, and 13A, the need for one or more optical filters 1101, 1103, 1105, 1107, 1109, and 1111 may be eliminated if one or more of the internal coupling optical elements 700, 710, and 720 have sufficiently high color selectivity for the color of light that is intended to be internally coupled into the associated waveguide.

[0154] Other methods of reducing incoupling of light having a particular color into an unintended waveguide may be used instead of, or in addition to, employing optical filters. For example, consider a display system that includes a projector that outputs light corresponding to two different color images (e.g., a red image and a blue image) from a single pupil or two pupils that are displaced with respect to each other.

[0155] The display system further comprises a waveguide assembly comprising a first waveguide 670 having a first incoupling optical element 700 configured to incoupling light corresponding to a first color image (e.g., a blue image) and a second waveguide 690 having a second incoupling optical element 720 configured to incoupling light corresponding to a second color image (e.g., a red image). Such a waveguide assembly is illustrated in Figs. 14A-14B. In various embodiments of a display system comprising a projector that outputs light corresponding to two different primary color images (e.g., a red image and a blue image) from two pupils that are displaced relative to each other, the first incoupling optical element 700 and the second incoupling optical element 720 can be vertically aligned with the respective pupils that emit light corresponding to the images to be incoupling into the respective waveguides. Thus, in such embodiments, the first incoupling optical element 700 and the second incoupling optical element 720 are also displaced relative to each other (e.g., by a distance "D" as shown in Fig. 14A). It should be understood that one or more additional waveguides may be provided for incoupling and outcoupling light for one or more additional primary color images, such that the primary color images together form a full color image, as discussed herein.

[0156] In various embodiments of a display system comprising a projector that outputs light corresponding to two different color images (e.g., a red image and a blue image) from a single pupil, the first in-coupling optical element 700 and the second in-coupling optical element 720 may be vertically aligned with the single pupil of the projector that outputs light corresponding to the first and second color images. However, the first in-coupling optical element 700 and the second in-coupling optical element 720 may be laterally displaced relative to one another by a distance "D" as shown in FIG. 14A. Displacing the first in-coupling optical element 700 and the second in-coupling optical element 720 laterally relative to one another may advantageously reduce unintended coupling of light into the waveguide, improve color selectivity, and reduce crosstalk and / or illusions.

[0157] Displacing the incoupling optical element 720 laterally relative to the incoupling optical element 700 can also be advantageous when the light output from a single pupil of the projector is incident on the waveguide assembly at an angle, as shown in Figure 14B. In this configuration, for some angles of incidence, the portion of the light corresponding to the first color image that is transmitted through the incoupling optical element 700 does not enter the incoupling optical element 720 and is therefore not incoupling into the waveguide 690.

[0158] Certain details related to laterally shifting the internal coupling optical element will now be discussed. With reference to FIG. 15A, a display system including a projector may output light corresponding to two different color images (e.g., a red image represented by light rays 1007n and 1007a, and a blue image represented by light rays 1005n and 1005a). In some other embodiments, light beams corresponding to two different color images (e.g., a red image and a blue image) may be emitted from two different pupils, such as, for example, pupil 1401 and pupil 1403 shown in FIG. 14. In some embodiments, the two pupils emitting light beams corresponding to two different color images (e.g., a red image and a blue image) may at least partially overlap, as shown in FIG. 14. However, in some other embodiments, the two pupils emitting light beams corresponding to two different color images (e.g., a red image and a blue image) may be spatially non-overlapping, such as, for example, pupil 1401 and pupil 1403. In some other embodiments, two pupils, such as pupil 1401 and pupil 1403, emitting light beams corresponding to two different color images (e.g., a red image and a blue image), may completely overlap such that the light beams corresponding to the two different color images (e.g., a red image and a blue image) may be considered to be emitted from a single exit pupil. Single-pupil systems may be particularly advantageous because light directed to the internal coupling optical element may pass through a similar portion (e.g., the center) of the projection optics, thereby reducing possible distortions that may occur if the light passes through different portions of the projection optics. In addition, single-pupil systems may advantageously require a smaller projection lens system than multiple-pupil systems.

[0159] The display system further comprises a waveguide assembly comprising a first waveguide 670 having a first incoupling optical element 700 configured to incoupling light corresponding to a first color image (e.g., a blue image) represented by light rays 1005n and 1005a, and a second waveguide 690 having a second incoupling optical element 720 configured to incoupling light corresponding to a second color image (e.g., a red image) represented by light rays 1007n and 1007a. Such a waveguide assembly is illustrated in FIG. The first in-coupling optical element 700 is vertically aligned with a first pupil 1401 of the projector, which emits light corresponding to a first color image, represented by light rays 1005n and 1005a, and the respective pupil of the second in-coupling optical element 720 is vertically aligned with a second pupil 1403 of the projector, which emits light corresponding to a first color image, represented by light rays 1007n and 1007a. The first in-coupling optical element 700 and the second in-coupling optical element 720 are laterally displaced relative to one another by a distance "D" as shown in FIG. 15A. Displacing the first in-coupling optical element 700 and the second in-coupling optical element 720 laterally relative to one another may advantageously reduce unintended coupling of light into the waveguide, improve color selectivity, and reduce crosstalk and / or illusions, as discussed herein. As discussed herein, pupils 1401 and 1403 may overlap, and in some embodiments are preferably the same single pupil of the projection system that directs light to the first and second internal coupling optical elements 700 and 720.

[0160] Without being bound by theory, the beam of light emitted from the projector pupil is conical and comprises rays incident normal to the surface of the waveguide, e.g., rays 1005n and 1007n, and also rays incident at an angle to the normal to the surface of the waveguide, e.g., rays 1005a and 1007a. A portion of the light of the first color image may propagate through the first in-coupling optical element and impinge on the second in-coupling optical element 720. Lateral displacement of the first in-coupling optical element 700 and the second in-coupling optical element 720 relative to each other may reduce the amount of light corresponding to the first color image in-coupled into the second waveguide 690 and / or the amount of light corresponding to the second color image in-coupled into the first waveguide 670.

[0161] For example, by laterally displacing the first internal coupling optical element 700 and the second internal coupling optical element 720 relative to each other, a portion of the light corresponding to the first color image that is incident obliquely with respect to the normal to the surface of the second waveguide 690 does not enter the second internal coupling optical element 720, as shown in FIG. 15A, and is therefore not internally coupled into the second waveguide 690.

[0162] For example, consider that a portion of light corresponding to a first color image is incoupling into the second waveguide 690. The incoupling portions of light corresponding to the first color image may subsequently generate partial images when output from the waveguide 690. These partial images may degrade the contrast ratio and / or resolution of the first color image output from the first waveguide 670 and / or cause ghosting (by providing a ghosting of the first color image output from the first waveguide 670). As shown in FIG. 15A, reducing the amount of obliquely incident light corresponding to the first color image incoupling into the second waveguide 690 may reduce or mitigate the degradation of the contrast ratio and / or resolution of the first color image output from the first waveguide 670 and / or reduce the amount of ghosting in the first color image output from the first waveguide 670.

[0163] Some embodiments of a display device in which the first incoupling optical element 700 and the second incoupling optical element 720 are laterally displaced relative to one another may omit a color filter configured to absorb light having wavelengths that are not desired to be incoupled into individual ones of the waveguides. However, some embodiments of a display device in which the first incoupling optical element 700 and the second incoupling optical element 720 are laterally displaced relative to one another may also include one or more optical filters (e.g., optical filters similar to optical filter 1101 or optical filter 1103) configured to absorb light having wavelengths that are not desired to be incoupled into individual ones of the waveguides. For example, as shown in FIG. 15B, in an otherwise identical arrangement to that of FIG. 12A, the second incoupling optical element 720 and associated color filter 1103 may be laterally displaced relative to the first incoupling optical element 700.

[0164] 15A, the in-coupling optical element 720 is displaced laterally to the right of the in-coupling optical element 700. However, in other embodiments, the in-coupling optical element 720 may be displaced laterally to the left of the in-coupling optical element 700, or into or out of the page. The amount of lateral displacement between a pair of in-coupling optical elements and the direction of displacement of one in-coupling optical element relative to another in-coupling optical element (e.g., to the right or left and / or into or out of the page) may depend on the overall image quality of the image projected out from the waveguide.

[0165] In some embodiments, the direction of displacement (e.g., to the right or left and / or into or out of the page) and the amount of lateral displacement between the pair of internal coupling optical elements may be selected to reduce the perceptibility of a residual image relative to the intensity of a desired image projected out of the waveguide. For example, in some embodiments, the direction of displacement (e.g., to the right or left and / or into or out of the page) and the amount of lateral displacement between the pair of internal coupling optical elements may be selected to reduce the intensity of the residual image to about 1 / 100 of the intensity of a desired image projected out of the waveguide. As another example, in some embodiments, the direction of displacement (e.g., to the right or left and / or into or out of the page) and the amount of lateral displacement between the pair of internal coupling optical elements may be selected such that a residual image cannot be perceived by the average human eye.

[0166] In some embodiments, the direction of displacement and the amount of lateral displacement between the pair of internal coupling optical elements may be selected to increase the brightness and / or contrast ratio of a desired image projected out from the waveguide. In some embodiments, the direction of displacement (e.g., to the right or left and / or into or out of the page) and the amount of lateral displacement between the pair of internal coupling optical elements may be selected to increase the resolution as perceived by an average human of a desired image projected out from the waveguide.

[0167] In some embodiments, the amount of lateral displacement between a pair of internal coupling optical elements may be greater than or equal to about 5% of the width of one of the first or second internal coupling optical elements (e.g., greater than or equal to about 10%, greater than or equal to about 15%, greater than or equal to about 20%, greater than or equal to about 25%, greater than or equal to about 30%, greater than or equal to about 40%) such that the overall image quality of the desired image projected out of the waveguide is improved (e.g., such that the intensity of the residual image from the waveguide with one of the internal coupling optical elements is less than or equal to about 1 / 100 of the intensity of the desired image projected out of the waveguide with the other of the internal coupling optical elements and / or such that the brightness, resolution, and / or contrast ratio of the desired image projected out of the waveguide of the first of the internal coupling optical elements is improved). Additionally, in some embodiments, the amount of lateral displacement between a pair of internal coupling optical elements can be less than 50% (e.g., less than about 40%, less than about 30%, or less than about 20%) of the width of the first or second internal coupling optical element. In cases where the internal coupling optical elements have different widths, the relevant width for determining the displacement, in some embodiments, is the shortest width.

[0168] Without being bound by theory, displacing the pair of in-coupling optical elements so that there is no overlap is desirable in terms of improving the overall image quality of the desired image projected out of the waveguide. However, displacing the pair of in-coupling optical elements relative to each other so that there is no overlap would require displacing the corresponding exit pupils of the projectors emitting the light to be in-coupled by the respective ones of the pair of in-coupling optical elements so that the exit pupils do not overlap. This may result in an increase in the size of the projector and / or generate undesirable optical artifacts. Displacing the pair of in-coupling optical elements and the corresponding exit pupils of the projector so that they partially overlap may be useful to reduce the size of the projector and / or reduce optical artifacts without adversely affecting the image quality of the desired image projected out of the waveguide. In some embodiments, the amount of lateral displacement is selected such that a single-pupil projection system may be utilized to direct image light to the in-coupling optical elements, while the amount of displacement is advantageously selected to be small enough to reduce the occurrence of residual images from the underlying waveguide. Such a displacement may cause a portion of the image not to be displayed because the displacement of the incoupling optical element may cause a portion of the incoupling optical element not to receive light that it would otherwise receive if perfectly aligned with the exit pupil and other incoupling optical elements. However, without being limited by theory, it is believed that the potential loss of a portion of the image has less of an impact on image quality than a residual image that may result from a lower waveguide unintentionally in- and out-coupling light intended for the upper waveguide. It should be understood that when referring to the image light stream output by the projection system, the lower waveguide is downstream of the upper waveguide.

[0169] In some embodiments, the direction of displacement (e.g., to the right or left and / or into or out of the page) and the amount of lateral displacement between the pair of internal coupling optical elements may be determined using a simulation tool that includes a virtual model of a display device including a waveguide stack and an internal coupling optical element. The direction of displacement (e.g., to the right or left and / or into or out of the page) and the amount of lateral displacement between the pair of internal coupling optical elements may be iteratively adjusted using the simulation tool to improve the overall image quality of the desired image projected out of the waveguide. For example, the direction of displacement and the amount of lateral displacement between the pair of internal coupling optical elements may be iteratively adjusted using the simulation tool to reduce the intensity of the residual image relative to the intensity of the desired image projected out of the waveguide. As another example, the direction of displacement and the amount of lateral displacement between the pair of internal coupling optical elements may be iteratively adjusted using the simulation tool to improve at least one of the brightness, contrast ratio, and / or resolution as perceived by an average human eye of the desired image projected out of the waveguide.

[0170] In addition to displacing an internal coupling optical element relative to another internal coupling optical element, one or more parameters of an individual element (e.g., grating element) of an internal coupling optical element may be adjusted to vary the internal coupling efficiency of different colors of light incident at different angles. For example, without subscribing to any particular theory, light incident at a negative incidence angle (e.g., incident to the right of the normal to the surface from a direction) may be internally coupled less efficiently compared to light incident at a positive incidence angle (e.g., incident to the left of the normal to the surface from a direction), as shown in FIG. 16. Thus, the direction of displacement of one internal coupling optical element may be adjusted by considering the efficiency of internal coupling light incident at negative and positive incidence angles. As another example, without subscribing to any particular theory, the internal coupling efficiency of an internal coupling optical element to light incident at different incidence angles may be changed by adjusting one or more parameters of the height and / or pitch of an individual element (e.g., grating element) of the internal coupling optical element.

[0171] For example, the incoupling optical elements of the display device may be configured such that light of a first color incident at a positive angle of incidence is incoupling by a corresponding incoupling optical element into a waveguide configured to incoupling light of a second color such that a first color image projected from the waveguide may cause a perceptible afterimage. In such an embodiment, the incoupling optical element may be displaced along a direction to avoid light of the first color incident at a positive angle of incidence and reduce afterimage.

[0172] In a display device comprising waveguides associated with multiple depth planes, the incoupling optical elements of the waveguides associated with different depth planes may be separated from one another without any spatial overlap, which may be advantageous in reducing accidental incoupling of light corresponding to images for the waveguides associated with different depth planes.

[0173] 17 illustrates an embodiment of a display device comprising waveguides associated with two different depth planes. A first waveguide stack 1501 is associated with a first depth plane D1. The first waveguide stack 1501 comprises waveguides 1505a, 1505b, and 1505c, each waveguide of the first waveguide stack 1501 configured to incouple a different color of light (e.g., red, green, or blue) corresponding to a first depth plane image projected from a projector exit pupil 1513. The light is incoupled into the waveguides 1505a, 1505b, and 1505c using incoupling optical elements 1507a, 1507b, and 1507c, respectively. In various embodiments, the incoupling optical elements 1507a, 1507b, and 1507c may be spatially separated from one another such that they overlap as discussed above. As discussed above, the direction of displacement and the amount of lateral displacement between the individual internal coupling optical elements 1507a, 1507b, and 1507c may be configured to improve at least one of the brightness, contrast ratio, and / or resolution as perceived by the average human eye of the first depth plane image projected out from the first waveguide stack 1501 (e.g., by reducing the occurrence of residual images output from the underlying waveguide).

[0174] In some embodiments, the exit pupil 1513 may comprise a single pupil configured to project the first depth plane image and emitting different colors of light corresponding to the first depth plane image. Alternatively, in various embodiments, the exit pupil 1513 may comprise multiple exit pupils 1513a, 1513b, and 1513c, each configured to emit different colors of light corresponding to the first depth plane image. In such embodiments, the multiple exit pupils 1513a, 1513b, and 1513c may each be positioned to be approximately vertically aligned with a corresponding incombining optical element 1507a, 1507b, and 1507c, respectively, configured to incombine the emitted colors of light.

[0175] The display device depicted in FIG. 17 includes a second waveguide stack 1503 associated with a second depth plane D2. The second waveguide stack 1503 includes waveguides 1509a, 1509b, and 1509c configured to in-couple different colors of light (e.g., red, green, or blue) for displaying a second depth plane image projected from a projector exit pupil 1515. The waveguides 1509a, 1509b, and 1509c in-couple the light using in-coupling optical elements 1511a, 1511b, and 1511c, respectively. In various embodiments, the in-coupling optical elements 1511a, 1511b, and 1511c may be spatially separated from one another such that they overlap as discussed above. As discussed above, the direction of displacement and the amount of lateral displacement between the individual internal coupling optical elements 1511a, 1511b, and 1511c may be configured to improve at least one of the brightness, contrast ratio, and / or resolution as perceived by the average human eye of the second depth plane image projected out from the second waveguide stack 1503 (e.g., by reducing the occurrence of residual images output from the underlying waveguide).

[0176] In some embodiments, the exit pupil 1515 configured to project the second depth plane image may comprise a single pupil that emits different colors of light corresponding to the first depth plane image. Alternatively, in various embodiments, the exit pupil 1515 configured to project the second depth plane image may comprise multiple exit pupils 1515a, 1515b, and 1515c configured to emit different colors of light corresponding to the second depth plane image. In such embodiments, the multiple exit pupils 1515a, 1515b, and 1515c may each be positioned to be approximately vertically aligned with a corresponding incombining optical element 1511a, 1511b, and 1511c, respectively, configured to incombine the emitted colors of light.

[0177] 17, the exit pupils 1513 and 1515 projecting the first and second depth plane images, and the internal combining optical elements 1507a-1507c and 1511a-1511c configured to internally combine the first and second depth plane images, are spatially separated without any overlap (when viewed in a top-down view from the perspective of the exit pupils). Spatially separating the exit pupils 1513 and 1515 projecting the first and second depth plane images, and the internal combining optical elements 1507a-1507c and 1511a-1511c configured to internally combine the first and second depth plane images, without any overlap, may reduce internal combining of the second depth plane image within the first waveguide stack 1501, and vice versa. The exit pupils 1513 and 1515, which output light for the first and second depth plane images, and the internal coupling optical elements 1507a-1507c and 1511a-1511c may be spatially separated along a lateral direction and / or along a transverse direction within the plane of the waveguides 1505a-1505c and 1509a-1509c.

[0178] Various examples of devices (e.g., optical devices, display devices, illuminators, integrated optical devices, etc.) and systems (e.g., illumination systems) have been provided. Any of these devices and / or systems may be included within a head mounted display system to couple light (e.g., using one or more internal coupling optical elements) into a waveguide and / or eyepiece to form an image. In addition, the devices and / or systems may be relatively small (e.g., less than 1 cm) such that one or more of the devices and / or systems may be included within a head mounted display system. For example, the devices and / or systems may be small relative to the eyepiece (e.g., less than one-third the length and / or width of the eyepiece).

[0179] In the foregoing specification, the invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and changes may be made therein without departing from the broader spirit and scope of the invention. For example, although some examples are discussed with reference to a projector having multiple pupils (e.g., multiple exit pupils) for outputting light, it should be understood that any image light source or multiple image light sources may be utilized to provide image light for incoupling into the incoupling optical element. As an example, multiple projectors may be utilized in some embodiments to provide image light to the incoupling optical element. Additionally, in some figures, in an orientation where light from the projectors is directed downward toward the waveguide, the incoupling optical element is shown as being disposed along the rear or bottom major surface of the waveguide and thus operating in a reflective mode (such that incident light is incoupling into the waveguide by reflecting the light at an angle appropriate for TIR within the waveguide). In some other embodiments, in an orientation where light from the projector is directed downward towards the waveguide, the incoupling optical element may be located on the front or upper major surface of the waveguide and thus operate in a transmissive mode (such that incident light is incoupling into the waveguide by transmitting the light through the incoupling optical element, and the light exits the incoupling optical element at an angle appropriate for TIR within the waveguide). The present specification and drawings are therefore to be regarded in an illustrative rather than a limiting sense.

[0180] Indeed, it should be understood that the systems and methods of the present disclosure each have several innovative aspects, none of which is solely responsible for or required for the desirable attributes disclosed herein. The various features and processes described above may be used independently of one another or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of the present disclosure.

[0181] Certain features described herein in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in a combination and may be initially exemplified as such, one or more features from the exemplified combination may in some cases be deleted from the combination, and the exemplified combination may be subject to a subcombination or variation of the subcombination. No single feature or group of features is required or essential for every embodiment.

[0182] In particular, it should be understood that conditional terms used herein, such as "can," "could," "might," "may," "eg," and the like, are generally intended to convey that certain embodiments include certain features, elements, and / or steps, while other embodiments do not, unless specifically stated otherwise or understood otherwise within the context as used. Thus, such conditional terms are generally not intended to imply that features, elements, and / or steps are in any way required for one or more embodiments, or that one or more embodiments necessarily include logic for determining whether those features, elements, and / or steps are included or performed in any particular embodiment, with or without authorial input or prompting. The terms "comprising," "including," "having," and the like, are synonymous and are used inclusively in a non-limiting manner and do not exclude additional elements, features, acts, operations, etc. Also, the term "or", for example, when used to connect a list of elements, is used in its inclusive sense (and not its exclusive sense) so that the term "or" means one, some, or all of the elements in the list. In addition, the articles "a", "an", and "the" as used in this application and the accompanying examples should be interpreted to mean "one or more" or "at least one" unless otherwise specified. Similarly, although operations may be depicted in the figures in a particular order, it should be recognized that such operations need not be performed in the particular order shown, or in sequential order, or that all of the illustrated operations need not be performed to achieve desirable results. Additionally, the figures may diagrammatically depict one or more exemplary processes in the form of a flow chart. However, other operations not depicted may also be incorporated within the diagrammatically illustrated exemplary methods and processes.For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the illustrated operations. In addition, operations may be rearranged or reordered in other embodiments. In some situations, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the program components and systems described may generally be integrated together in a single software product or packaged in multiple software products. In addition, other embodiments are within the scope of the following examples. In some cases, the actions recited in the examples may be performed in a different order and still achieve desirable results.

[0183] Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the present disclosure, principles and novel features disclosed herein.

Claims

1. 1. A display system comprising: a single pupil projector that projects an incident beam of light along a y-axis; a stack of waveguides vertically arranged along the y-axis at top, center, and bottom positions as a second waveguide, a first waveguide, and a third waveguide, respectively, the stack of waveguides comprising: a first absorptive optical filter in the first waveguide, the first absorptive optical filter being transmissive to light of an incident beam of light in a first wavelength range and absorptive to light of a wavelength different from the first wavelength range; a first incoupling optical element of the first waveguide, the first incoupling optical element configured to receive light transmitted through the first absorptive optical filter, the first incoupling optical element configured to incoupling light of the first wavelength range into the first waveguide; a first major surface and a second major surface of the first waveguide; a second absorptive optical filter on one or both of the first major surface or the second major surface of the first waveguide; when viewed in a top-down view along the y-axis, the first absorptive optical filter is laterally displaced in the x-z plane from the second absorptive optical filter, and either the first absorptive optical filter or the second absorptive optical filter is laterally displaced with respect to an exit pupil of the single pupil projector to absorb the incident beam of light having an incidence angle that contributes to degradation of image quality, and the first absorptive optical filter has a different attenuation coefficient for the wavelengths of light different from the first wavelength range when compared to the attenuation coefficient of the second absorptive optical filter for the wavelengths of light different from the first wavelength range. A display system comprising:

2. 2. The display system of claim 1, wherein the first incoupling optical element is on the first major surface of the first waveguide or on the second major surface of the first waveguide.

3. The display system of claim 1 , wherein the first absorptive optical filter comprises a dye.

4. The display system of claim 1 , wherein the first incoupling optical element is configured to transmit light having a range of wavelengths different than the first range of wavelengths.

5. The second waveguide comprises: a first major surface and a second major surface; a second incoupling optical element configured to incoupling light having a second range of wavelengths different from the first range of wavelengths into the second waveguide; The display system of claim 1 , comprising:

6. 6. The display system of claim 5, wherein at least a portion of the first incoupling optical element and at least a portion of the second incoupling optical element overlap in the xz plane when viewed in a top-down view along the y-axis.

7. the third waveguide having a first major surface and a second major surface; 6. The display system of claim 5, wherein a third incoupling optical element of the third waveguide is configured to incoupling light from an incident beam of light having a third wavelength range into the third waveguide.

8. 8. The display system of claim 7, wherein the third incoupling optical element is on one of the first major surface of the third waveguide or the second major surface of the third waveguide.

9. 8. The display system of claim 7, wherein at least a portion of the third internal coupling optical element overlaps with the first internal coupling optical element and the second internal coupling optical element in the xz plane when viewed in a top-down view along the y-axis.

10. 8. The display system of claim 7, further comprising a fourth absorptive optical filter between the second waveguide and the third waveguide above the third incoupling optical element along the y-axis.

11. The display system of claim 10 , wherein the fourth absorptive optical filter comprises a dye.

12. 6. The display system of claim 5, wherein the second incoupling optical element is on the first major surface of the second waveguide or on the second major surface of the second waveguide.

13. the second waveguide is above the first waveguide along the y-axis; 13. The display system of claim 12, wherein a third absorptive optical filter on a major surface of the second waveguide and displaced laterally in the x-z plane from the second incoupling optical element is configured to absorb incoupling light having a wavelength different from the second wavelength range.

14. The display system of claim 13 , wherein the third absorptive optical filter comprises a dye.

Images