waveguide components

Abstract

A waveguide assembly includes: a first waveguide plate arranged to receive image-carrying light and amplify the pupil size of the image-carrying light parallel to a first axis, the first waveguide plate including a reflective coupling region arranged to couple the image-carrying light into the first waveguide plate under total internal reflection (TIR) ​​and a reflective coupling region located on the same side of the first waveguide plate as the reflective coupling region and arranged to decouple the image-carrying light from the first waveguide plate by means of reflection; a second waveguide plate arranged to couple at least a portion of the coupled image-carrying light from the first waveguide plate into the second waveguide plate and amplify the pupil size parallel to a second axis, the second axis being substantially orthogonal to the first axis; wherein the second waveguide plate includes a diffraction coupling region and a transmission diffraction coupling region, through which a user can simultaneously view a real-world image and the coupled image-carrying light.

Description

[0001] This invention application is a divisional application of the invention patent application filed on September 8, 2021, with application number 202180062306.8 (international application number PCT / GB2021 / 052309) and title "Waveguide Component". Technical Field

[0002] This invention relates to the field of optical technology, and more specifically, to a waveguide assembly. Background Technology

[0003] For augmented reality applications, a large field of view (FOV) is desirable for the display. Due to variations in user body shape, a large exit pupil is also desired to allow for versatile display assembly and to enable movement of the user's eye relative to the display surface. To reduce the overall size of the optics used to display images while providing a large FOV and exit pupil, pupil expansion technology is employed. Summary of the Invention

[0004] On one hand, the present invention provides a waveguide assembly. The waveguide assembly includes: a first waveguide plate arranged to receive image-carrying light and amplify the pupil size of the image-carrying light parallel to a first axis, the first waveguide plate including a reflective coupling region arranged to couple the image-carrying light into the first waveguide plate under total internal reflection (TIR) ​​and a reflective coupling region located on the same side of the first waveguide plate as the reflective coupling region and arranged to decouple the image-carrying light from the first waveguide plate by means of reflection; and a second waveguide plate arranged to couple at least a portion of the coupled image-carrying light from the first waveguide plate into the second waveguide plate and amplify the pupil size parallel to a second axis, the second axis being substantially orthogonal to the first axis; wherein the second waveguide plate includes a diffraction coupling region on the surface of the second waveguide plate and a transmission diffraction coupling region embedded within the second waveguide plate, through which a user can simultaneously view a real-world image and the coupled image-carrying light.

[0005] On the other hand, the present invention provides a binocular device. This binocular device includes the waveguide assembly described above.

[0006] In another aspect, the present invention provides augmented reality glasses. These augmented reality glasses include the binocular device described above.

[0007] According to another aspect of this disclosure, a head-mounted display or head-up display is provided. The head-mounted display or head-up display includes the waveguide assembly described above. Attached Figure Description

[0008] Figure 1 A waveguide configured to extend the image-carrying pupil in a single dimension is shown.

[0009] Figure 2a It is an extended diagram of the waveguide assembly used to expand the image-carrying pupil in two dimensions.

[0010] Figure 2b This is a diagram of a waveguide assembly used to expand the image-carrying pupil in two dimensions.

[0011] Figure 3a A single waveguide with a fixed-pitch grating is shown, which couples red light into the waveguide.

[0012] Figure 3b This illustrates a grating with the same fixed spacing, coupling blue light into a waveguide. Figure 3a The same single waveguide.

[0013] Figure 4 A pupil expander using a reflective coupling element instead of a diffractive element is shown.

[0014] Figure 5a A side view of a reflective waveguide plate is shown.

[0015] Figure 5b A top view of a reflective waveguide plate is shown.

[0016] Figure 5c A top view of a transmission waveguide plate is shown.

[0017] Figure 5d A side view of a transmission waveguide plate is shown.

[0018] Figure 6 A coplanar waveguide device comprising three waveguide plates is shown.

[0019] Figure 7a A single ray in a TIR waveguide is shown.

[0020] Figure 7b A single ray coupled out of the waveguide is shown.

[0021] Figure 8a A single ray is shown confined in a waveguide comprising two waveguide plates joined together.

[0022] Figure 8b A single ray is shown exiting from a waveguide comprising two waveguide plates joined together.

[0023] Figure 9 A binocular device is shown.

[0024] Figure 10An alternative binocular device is shown. Detailed Implementation

[0025] like Figure 1 As shown, pupil expansion can be achieved using a waveguide 100 including a diffraction grating. The waveguide 100 includes an input grating 110 and an output grating 120. The output grating is configured to output light from the waveguide and expand the light in a single dimension. A grating is a periodic structure that can separate and diffract light into different directions. This periodic structure is commonly referred to as a line and will be mentioned so throughout the specification.

[0026] As shown in Figure 2, expansion in two dimensions can be achieved using two orthogonal waveguides. The grating lines on each waveguide are substantially orthogonal to each other. An input pupil is coupled into the first waveguide 100a using an input grating 110a. The input pupil expands within waveguide 100a and is coupled out of waveguide 100a through an output grating 120a.

[0027] The second waveguide 100b is arranged such that the grating lines of the second extended grating 120b are substantially orthogonal to the grating lines of the first extended grating 120a, and such that light output from the first waveguide via the output grating 120a is coupled into the second waveguide 100b via the input grating 110b. The output grating 120b of the second waveguide 100b is used to expand the pupil in a second direction orthogonal to the first direction and to output light from the second waveguide.

[0028] Because a low-efficiency grating is used to perform cross-coupling between the first and second waveguides, therefore... Figure 2a and Figure 2b The layout shown is inefficient. Because... Figure 2a and Figure 2b The arrangement uses a diffraction grating, and therefore the arrangement also has inherent field of view (FOV) and wavelength bandwidth limitations.

[0029] For a single diffractive waveguide with a fixed-pitch input grating, it is difficult to couple a large wavelength range over a large FOV because the diffraction angles for certain wavelengths fall outside the TIR conditions of the glass substrate.

[0030] Therefore, for wide FOV images that include multiple wavelengths (i.e., panchromatic), both the horizontal and vertical expanders in this setup typically require multiple stacked waveguides. Figure 3a The image shows a single waveguide with a fixed-pitch input grating. (Example:) Figure 3a As shown, when red light is input, the full red FOV is coupled under TIR. However, as Figure 3b As shown, when blue light is input, most of the blue FOV is emitted because the FOV cannot be coupled by TIR constraint.

[0031] An alternative is to use a pupil expander that employs a reflective coupling element instead of a diffractive element. This is in Figure 4 As shown in the image.

[0032] Waveguides, including reflective or transmissive input coupling devices such as prisms, do not have the same chromatic constraint as diffraction gratings, and multiple wavelengths can be coupled over a large field of view (FOV). Therefore, with... Figure 3a and Figure 3b Compared to other arrangements, a single waveguide can be used to constrain a full-width FOV image under TIR. A reflective output structure attached to the waveguide plate can also output waveguide light more efficiently than a typical diffraction grating.

[0033] Reflective output couplers used solely for pupil expansion (i.e., in the case of horizontal expanders) do not have transmission / transparency requirements and can therefore be coated for high reflectivity (high-efficiency mirror coating), where uniform output is produced with graded efficiency.

[0034] Because multiple reflective surfaces are used within the field of view, optimizing reflective coupling structures to maintain a sharp perspective path with minimal artifacts within the field of view can be challenging. In contrast, typical diffractive coupling structures can be optimized for high transparency with minimal artifacts, especially when embedded within a glass substrate, because the nanoscale diffractive structures used are imperceptible to the human eye.

[0035] Therefore, combining a reflective pupil expander with a diffractive pupil expander can produce a combined two-dimensional pupil expander that incorporates the best quality of both technologies.

[0036] Reference Figures 5a to 5d A waveguide assembly 500 according to some examples is described. The waveguide assembly 500 includes a first waveguide plate 500a and a second waveguide plate 500b.

[0037] A first waveguide 500a is arranged to receive image-carrying light and amplify the image-carrying light parallel to a first axis. The first waveguide 500a includes a first input coupling device 510a arranged to couple light into the first waveguide under total internal reflection (TIR). The first waveguide 500a also includes a first output coupling region 520a arranged to expand the pupil in a direction parallel to the first axis by means of reflection. The first output coupling region 520a is further arranged to couple the image-carrying light out of the first waveguide 500a.

[0038] The first waveguide plate 500a is in Figure 5a The middle is shown in a side view, and in Figure 5b The image is shown in a top view.

[0039] The second waveguide 500b is arranged to couple at least a portion of the coupled light from the first waveguide 500a into the second waveguide 500b, and is arranged to extend the image-carrying light in a direction substantially parallel to the second axis. The second axis is substantially orthogonal to the first axis.

[0040] The second waveguide plate 500b includes a diffraction coupling region 510b and a transmission diffraction coupling region 520b. Through the diffraction coupling region 510b and the transmission diffraction coupling region 520b, users can simultaneously view real-world images and the coupled-out image carrying light.

[0041] The second waveguide plate 500b is in Figure 5c It is shown in a top view, and in Figure 5d The image is shown in a side view.

[0042] The first waveguide plate 500a, including the first output coupling region 520a using reflection technology, can support a large FOV and spectral range within a single plate arrangement. The first waveguide plate 500a, including the first output coupling region 520a, can be optimized for high efficiency and uniformity without requiring transparency.

[0043] In some examples, grading can be performed by changing the size, shape, and spacing of the structure, preferably non-linearly.

[0044] In some examples, the height or depth of the grating (e.g., from 10's μm to 100's μm) can be varied, preferably within the range of 10's μm to 100's μm.

[0045] In some examples, the spacing between adjacent features can be changed, preferably within the range of 10's μm to 1000's μm (e.g., 10's μm to 1000's μm).

[0046] In some examples, the angle of the blaze face can be changed, preferably within the range of 20 to 35 degrees.

[0047] The gradient of a feature can be optimized to produce the best output uniformity for a specific setting, such as based on the desired FOV and output area.

[0048] The second waveguide 500b, using diffraction technology, can be optimized to have high perspective with minimal perspective artifacts, while expanding the vertical pupil over a large area.

[0049] In some examples, the first input coupling device 510a is attached to the outside of the first waveguide plate 500a. This allows the first input coupling device 510a to be manufactured separately and bonded or glued to the outside of the first waveguide plate 500a.

[0050] In some examples, the first input coupling device 510a may include a prism device, such as one or more prisms. The prism input device can be optimized to couple a wide range of wavelengths and a large field of view (FOV).

[0051] In some examples, the image-carrying light can be uniformly decoupled over the first decoupling region 520a.

[0052] In some examples, at least one of the first waveguide 500a and the second waveguide 500b may be curved and / or non-planar.

[0053] Since the user does not need to observe through the first waveguide 500a, the first waveguide 500a or the first output coupling region 520a can be substantially reflective and / or nontransmissive.

[0054] To achieve a wider field of view (FOV) with multiple wavelengths, multiple waveguides similar to the second waveguide plate 500b can be used in the coplanar waveguide assembly 600. This is in Figure 6 As shown in the diagram. Multiple wavelength waveguide components include a horizontal waveguide 610, a first vertical waveguide 620, and a second vertical waveguide 630. The horizontal waveguide 610 is substantially similar to the first waveguide 610 and includes an output coupling region arranged to extend the pupil in a direction parallel to the first axis by means of reflection. Figure 6 (Not shown in the image). The output coupling region is also arranged toward the first vertical waveguide 620 and the second waveguide 630 to couple the image-carrying light out of the horizontal waveguide 610.

[0055] The horizontal waveguide 610 is arranged parallel to the first axis to extend the pupil. The first vertical waveguide 620 and the second vertical waveguide 630 are arranged coplanar with the horizontal waveguide 610 and parallel to the second axis to extend the pupil, wherein the second axis is substantially orthogonal to the first axis. The first vertical waveguide 620 and the second vertical waveguide 630 are offset along a third axis by a minimum gap. The first and second vertical waveguides are substantially similar to the second waveguide 500b.

[0056] The gap may include an air gap, or it may be filled with a material such as optical adhesive.

[0057] In the coplanar waveguide assembly 600, the field of view (FOV) is effectively separated upon exiting the horizontal waveguide 610 due to the optical path employed within it. Two vertical waveguides can be arranged to receive only a portion of the FOV and couple it into their respective waveguides. The grating spacing of the two coupling gratings on the vertical waveguides may differ, as different grating spacings can be used to optimize the coupling efficiency for different portions of the FOV.

[0058] The coplanar waveguide assembly 600 may also include more than two vertical waveguide plates.

[0059] In some examples, at least one of the horizontal waveguide 610, the first vertical waveguide 620, and the second vertical waveguide 630 may be curved and / or non-planar.

[0060] In some examples, at least one of the first waveguide 500a and the second waveguide 500b may be formed from one or more substrates bonded together. An optical coating may be included between these bonded substrates.

[0061] In some examples, the optical coating may include a beam-splitting coating. The beam-splitting coating separates light into a transmitted portion and a reflected portion. The beam-splitting coating is typically formed of a low-refractive-index dielectric material and a high-refractive-index dielectric material (e.g., MgF2, SiO2, TiO2) or a metallic material (e.g., Al, Ag).

[0062] If the beam-splitting coating is placed between substrates or plates of varying thicknesses (e.g., substrate 1 is 1 mm thick and substrate 2 is 2 mm thick), then the rays begin to be split multiple times, resulting in many generations of rays being generated from a single source ray. This is in Figures 7a to 7b as well as Figures 8a to 8b As shown in the image.

[0063] exist Figure 7a In this case, a single ray propagates along the waveguide plate under TIR conditions. For example... Figure 7b As shown, when rays are output from the waveguide plate, there are gaps between the output rays.

[0064] exist Figure 8a In this process, a beam-splitting coating is used to bond two waveguide plates of different thicknesses together. A single ray interacts with the beam-splitting coating and is split into a transmitted beam and a reflected beam. The subsequently reflected and transmitted beams also interact with the beam-splitting coating. This process is repeated multiple times.

[0065] like Figure 8b As shown, when light is emitted from the waveguide plate, it interacts with... Figure 7b Compared to the previous example, the gap between the pupils is reduced.

[0066] Figure 6The diagram illustrates light passing through the first vertical waveguide 620 before being input into the second vertical waveguide 630. However, in some examples, light input to the second vertical waveguide 630 can be introduced from the horizontal waveguide 610 into the second waveguide 630 via a direct optical path. A direct optical path refers to the fact that the light does not interact with other elements before being input into the second vertical waveguide 630. The light can then interact with the first vertical waveguide 620, for example, between the first waveguide 620 and the second waveguide 630. Figure 8a and Figure 8b In the case where they are joined together as described.

[0067] Multiple individual waveguide components can be used to provide a binocular assembly, such as Figure 9 and Figure 10 As shown. In Figure 9 In the device shown, a reflective waveguide is positioned above the user's eyes. Figure 10 In the alternative device shown, reflective waveguides are positioned on either side of the user's eyes.

[0068] In some examples, Figure 9 and Figure 10 The device shown can be used as augmented reality glasses. In some examples, Figure 9 and Figure 10 The device shown can be used in head-mounted displays or head-up displays.

[0069] In addition, this disclosure also provides the following configurations:

[0070] 1. A waveguide assembly, comprising:

[0071] A first waveguide plate is arranged to receive image-carrying light and to amplify the pupil size of the image-carrying light parallel to a first axis. The first waveguide plate includes a first input coupling device arranged to couple the image-carrying light into the first waveguide plate under total internal reflection (TIR) ​​and a first coupling region arranged to decouple the image-carrying light from the first waveguide plate by means of reflection.

[0072] A second waveguide plate is arranged to couple at least a portion of the image-carrying light coupled from the first waveguide plate into the second waveguide plate and to enlarge the pupil size parallel to a second axis, the second axis being substantially orthogonal to the first axis; wherein...

[0073] The second waveguide plate includes a diffraction coupling region and a transmission diffraction coupling region. Through the diffraction coupling region and the transmission diffraction coupling region, the user can simultaneously view a real-world image and the image carrying light after coupling.

[0074] 2. The waveguide assembly according to configuration 1, wherein the first coupling region is attached to the outer surface of the first waveguide plate.

[0075] 3. The waveguide assembly according to any one of configuration 1 or 2, wherein the image-carrying light is uniformly decoupled over the coupling region.

[0076] 4. The waveguide assembly according to any of the foregoing configurations, wherein the first input coupling device includes a prism device.

[0077] 5. The waveguide assembly according to any of the foregoing configurations, wherein the first coupling region is substantially completely reflective and / or nontransmissive.

[0078] 6. The waveguide assembly according to any of the foregoing configurations further includes a third waveguide plate arranged to couple image-carrying light from the first waveguide plate that is not coupled into the second waveguide plate into the third waveguide plate under TIR conditions, and wherein the third waveguide plate includes a transmission diffraction coupling region through which a user can simultaneously view a real-world image and the coupled image-carrying light.

[0079] 7. The waveguide assembly according to configuration 6, wherein light coupled into the third waveguide plate does not interact with the second waveguide plate before being input into the second waveguide.

[0080] 8. The waveguide assembly according to configuration 6 or 7, wherein the coupling region of the second waveguide plate and the coupling region of the third waveguide plate have different grating spacing dimensions.

[0081] 9. The waveguide assembly according to any one of configurations 6 to 8, wherein the third waveguide plate and the second waveguide plate are coplanar on the first axis and the second axis and offset on the third axis, the third axis being orthogonal to the first axis and the second axis.

[0082] 10. The waveguide assembly according to any one of configurations 6 to 9, wherein the second waveguide plate and the third waveguide plate are joined together.

[0083] 11. The waveguide assembly according to configuration 10, wherein the second waveguide plate and the third waveguide plate have different thicknesses.

[0084] 12. The waveguide assembly according to any of the foregoing configurations, wherein the second waveguide is curved and / or non-planar.

[0085] 13. The waveguide assembly according to any of the foregoing configurations, wherein the first waveguide plate is arranged to receive collimated image-carrying light.

[0086] 14. The waveguide assembly according to any of the foregoing configurations further includes a collimating device for outputting a collimated exit pupil received by the first waveguide.

[0087] 15. A binocular device comprising: a first waveguide assembly according to any one of configurations 1 to 14 for providing a first image to a user's eye; and a second waveguide assembly according to any one of configurations 1 to 14 for providing a second image to a user's eye.

[0088] 16. An augmented reality glasses, including a binocular assembly as described in configuration 15.

[0089] 17. A head-mounted display or head-up display comprising a waveguide assembly according to any one of configurations 1 to 14.

Claims

1. A waveguide assembly, comprising: A first waveguide plate is arranged to receive image-carrying light and to amplify the pupil size of the image-carrying light parallel to a first axis. The first waveguide plate includes a reflective coupling region arranged to couple the image-carrying light into the first waveguide plate under total internal reflection (TIR) ​​and a reflective coupling region located on the same side of the first waveguide plate as the reflective coupling region and arranged to decouple the image-carrying light from the first waveguide plate by means of reflection. as well as A second waveguide plate is arranged to couple at least a portion of the image-carrying light from the first waveguide plate into the second waveguide plate and to enlarge the pupil size parallel to a second axis that is substantially orthogonal to the first axis. The second waveguide plate includes a diffraction coupling region on its surface and a transmission diffraction coupling region embedded within it. Through the diffraction coupling region and the transmission diffraction coupling region, users can simultaneously view a real-world image and the coupled-out image carrying light.

2. The waveguide assembly according to claim 1, wherein, The side of the first waveguide plate to which the reflective coupling-in region and the reflective coupling-out region are attached is the outer surface of the first waveguide plate.

3. The waveguide assembly according to claim 1, wherein, The image-carrying light is uniformly decoupled in the reflective coupling region.

4. The waveguide assembly according to claim 1, further comprising: A prism device disposed on the reflective coupling region.

5. The waveguide assembly according to claim 4, wherein, The prism device includes multiple prisms.

6. The waveguide assembly according to claim 1, wherein, The reflective coupling region is substantially completely reflective and / or nontransmissive.

7. The waveguide assembly according to claim 1, further comprising: A third waveguide plate is arranged to couple image-carrying light from the first waveguide plate that is not coupled into the second waveguide plate into the third waveguide plate under TIR conditions. The third waveguide plate includes a transmission diffraction coupling region, through which the user can simultaneously view the real-world image and the coupled image-carrying light. The second waveguide plate is located between the first waveguide plate and the third waveguide plate. The light coupled into the third waveguide plate enters the third waveguide plate via a direct optical path from the first waveguide plate that does not pass through the second waveguide plate, so that the light does not interact with the second waveguide plate before being input into the second waveguide plate. The diffraction coupling region of the second waveguide plate and the coupling region of the third waveguide plate have different grating spacing dimensions.

8. The waveguide assembly according to claim 7, wherein, The third waveguide plate and the second waveguide plate are coplanar on the first axis and the second axis.

9. The waveguide assembly according to claim 8, wherein, The second waveguide plate and the third waveguide plate are joined together or offset on a third axis, which is orthogonal to the first axis and the second axis.

10. The waveguide assembly according to claim 9, wherein, The second and third waveguide plates, which are joined together, have different thicknesses.

11. The waveguide assembly according to claim 7, wherein, The transmission diffraction coupling region of the third waveguide plate is embedded within the third waveguide plate.

12. The waveguide assembly according to claim 1, wherein, At least one of the first waveguide plate and the second waveguide plate is curved and / or non-planar.

13. The waveguide assembly according to claim 1, wherein, The first waveguide plate is arranged to receive collimated image-carrying light.

14. The waveguide assembly according to any of the preceding claims further comprises: A collimating device is used to output the collimated exit pupil received by the first waveguide plate.

15. A binocular device, comprising: The first waveguide assembly according to any one of claims 1 to 14 is used to provide a first image to the user's eye; And a second waveguide assembly according to any one of claims 1 to 14, for providing a second image to the user's eyes.

16. An augmented reality glasses comprising the binocular assembly of claim 15.

17. A head-mounted display or head-up display comprising a waveguide assembly according to any one of claims 1 to 14.

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