WO2021171289A1 - Mixed reality combiner - Google Patents
Mixed reality combiner Download PDFInfo
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- WO2021171289A1 WO2021171289A1 PCT/IL2021/050206 IL2021050206W WO2021171289A1 WO 2021171289 A1 WO2021171289 A1 WO 2021171289A1 IL 2021050206 W IL2021050206 W IL 2021050206W WO 2021171289 A1 WO2021171289 A1 WO 2021171289A1
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- waveguide
- reflectivity
- light
- facets
- combiner according
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/14—Beam splitting or combining systems operating by reflection only
- G02B27/141—Beam splitting or combining systems operating by reflection only using dichroic mirrors
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B27/0172—Head mounted characterised by optical features
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0081—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for altering, e.g. enlarging, the entrance or exit pupil
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/14—Beam splitting or combining systems operating by reflection only
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
- G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
- G02B6/0026—Wavelength selective element, sheet or layer, e.g. filter or grating
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
- G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
- G02B6/0031—Reflecting element, sheet or layer
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
- G02B6/004—Scattering dots or dot-like elements, e.g. microbeads, scattering particles, nanoparticles
- G02B6/0041—Scattering dots or dot-like elements, e.g. microbeads, scattering particles, nanoparticles provided in the bulk of the light guide
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
- G02B6/0055—Reflecting element, sheet or layer
Definitions
- Embodiments of the disclosure relate to an optical waveguide system configured to receive an image from a laser display engine at a relatively small input aperture and deliver the image to exit the waveguide at an expanded output coupling region to fill an enlarged eye motion box for viewing by a user.
- the proliferating head mounted displays (HMDs) and smart eyeware that are used to provide a user with any of the various new flavors of reality - augmented reality (AR), mixed reality (MR), parallel reality - superpose computer generated “virtual images” on “real images” that the user sees of a real environment in the user’s field of view (FOV).
- the virtual images may by way of example provide the user with entertainment and/or informational material related to the real images, a task performed by the user, and/or an explicit or implicit user request.
- An image presented to a user comprising a real and a virtual image may be referred to as an extended reality (XR) image and any of various hardware configured to provide a user with an XR image may be referred to generically as an XR display.
- XR extended reality
- a computer controlled display engine such as a liquid crystal on silicon (LCos), organic light emitting diode (OLED) or laser beam scanning (LBS) microdisplay, provides the virtual images.
- An optical element referred to as a combiner which is transparent to ambient light and through which the user views the real environment, receives and superposes the virtual images provided by the display engine on the real images to provide the user with XR images.
- the virtual images provided by the display engine are relatively small having a characteristic dimension of less than or equal to about 5 mm .
- the combiner receives the small virtual images at a relatively small input aperture and propagates the images to an output coupler that outputs the virtual images through an exit aperture of the combiner and into an eye motion box (EMB).
- EMB eye motion box
- the virtual images pass through the user’s aperture and onto the user’s retina to appear in the XR images as features of the real images which the user sees through the combiner.
- the combiner is generally configured having a relatively large, expanded aperture through which the combiner transmits many duplicates of the virtual images into the EMB.
- optical system of a practical XR display is generally required to satisfy a complex mix of ergonomic, technical, and financial constraints.
- the optical system is advantageously configured to have a comfortably large EMB, be advantageously small, lightweight, and energy efficient, and provide clear virtual images absent overly obtrusive artifacts such as image ghosts.
- An aspect of an embodiment of the disclosure relates to providing an optical waveguide combiner having an output coupler comprising an array of embedded dielectric partially reflective mirrors, hereinafter also referred to as facets, for expanding and coupling a virtual, optionally color, image generated by a laser display engine into a user EMB.
- the facets are configured to reflect with relatively large reflectivity incident light in a first range of incident angles into the user EMB.
- the facets are configured to have relatively low reflectivity and transmit light in substantially the same laser wavelength band with relatively large transmittance.
- the transmittance and reflectivity exhibit relatively small variability in the first and second angular ranges and over a range of wavelengths spanned by the laser wavelength band.
- the facets are formed having substantially achromatic transmission for visible light, also referred to as natural light, from the environment.
- the display engine comprises at least one laser that provides the display engine with light in red, green, and blue (RGB) bandwidths and processes the light to generate virtual RGB color images.
- the combiner introduces the color virtual images into the EMB with relatively high RGB image resolution and relatively low adulteration by image artifacts.
- the waveguide combiner comprises a waveguide having first and second parallel, total internal reflecting (TIR) surfaces.
- TIR total internal reflecting
- Light from the display engine enters the waveguide and is repeatedly reflected from and bounced back and forth between the TIR surfaces to propagate along the waveguide in a reduced, waveguide FOV (wFOV) to reach and be incident on the facets.
- the facets are evenly spaced and parallel and are tilted at a tilt angle as measured between a normal to the TIR surfaces and a normal to the facets.
- a component of a light ray in the wFOV that is parallel to the TIR normal reverses direction each time the light ray bounces off the first TIR surface and each time the light bounces off the second TIR surface.
- light rays incident on facets in only one of the first and second ranges of incident angles are selected for coupling out from the waveguide and into the EMB to provide the user with virtual images generated by the display engine.
- the range of incidence angles from which light rays in the wFOV are selected to provide the virtual images may be referred to as an “image incidence range”.
- the wFOV when oriented by TIR reflection in the waveguide to comprise light rays propagating in angular directions within the image incidence range may be referred to as an “image wFOV”.
- the non-selected range of incidence angles may be referred to as a “conjugate incidence range” and the wFOV, when oriented by TIR reflection in the waveguide to comprise light rays propagating in angular directions in the conjugate incidence range may be referred to as a “conjugate wFOV”.
- the tilt angle of the facets is determined to provide an advantageous angular separation between the image incidence range and the conjugate incidence range.
- the facets are configured having a reflectivity angular range, a transmittance angular range and a facet wavelength band.
- the facets exhibit relatively high reflectivity and relatively low variance with change in wavelength and incident angle.
- the facets exhibit relatively low reflectivity and corresponding high transmittance, and relatively low variance with change in wavelength and incident angle.
- the facet wavelength band spans a range of wavelengths that includes a lasing bandwidth of the laser that provides light that the display engine processes to generate virtual images and a range of wavelengths over which the lasing bandwidth may vary as a result, for example, of drift due to operating conditions and/or manufacturing tolerances.
- FIG. 1A schematically shows a waveguide combiner comprising a waveguide having an output coupler comprising an array of facets that expands an input aperture of the combiner in one direction to provide an expanded output through which the combiner transmits virtual images received through the input aperture into an EMB, in accordance with an embodiment of the disclosure;
- FIG. IB schematically shows a cross section of the combiner shown in Fig. 1A reflecting light from a laser display engine into a user EMB, in accordance with an embodiment of the disclosure
- FIG. 1C schematically shows an enlarged portion ofthe combiner shown in Fig. IB at which light from the laser display engine enters the combiner, in accordance with an embodiment of the disclosure
- Fig. ID schematically shows an enlarged portion of the combiner shown in Fig. IB at which light from the laser display engine exits the combiner into the EMB, in accordance with an embodiment of the disclosure
- Fig. IE shows a schematic graph of reflectivity as a function of angle of incidence of light from the laser display engine on the facets shown in Figs. 1A and 1C and reflectivity of the facets for natural light, in accordance with an embodiment of the disclosure;
- Fig. IF schematically shows optional lasing bandwidths for lasers in the display engine shown in Figs. 1 A and IB and matching facet wavelength bands of the facets shown in the figures, in accordance with an embodiment of the disclosure;
- Fig. 1G shows a graph of reflectivity as a function of wavelength for the facets shown in Figs. 1A and IB for a facet wavelength band of blue light, in accordance with an embodiment of the disclosure
- FIG. 2A schematically shows a cross section of a waveguide combiner similar to the combiner shown in Fig. 1A comprising facets tilted at an intermediate tilt angle reflecting light from a laser display engine into a user EMB, in accordance with an embodiment of the disclosure;
- Fig. 2B shows a schematic graph of reflectivity as a function of angle of incidence of light on the facets shown in Fig. 2A, in accordance with an embodiment of the disclosure;
- FIG. 3A schematically shows a cross section of a waveguide combiner similar to the combiner shown in Fig. 1A comprising facets tilted at a relatively large tilt angle reflecting light from a laser display engine into a user EMB, in accordance with an embodiment of the disclosure;
- Fig. 3B shows a schematic graph of reflectivity as a function of angle of incidence of light on the facets shown in Fig. 2A, in accordance with an embodiment of the disclosure
- FIG. 4 schematically shows a perspective view of a waveguide combiner comprising a system of waveguides that provides two dimensional aperture expansion, in accordance with an embodiment of the disclosure.
- adjectives such as “substantially” and “about” modifying a condition or relationship characteristic of a feature or features of an embodiment of the disclosure are understood to mean that the condition or characteristic is defined to within tolerances that are acceptable for operation of the embodiment for an application for which it is intended.
- a general term in the disclosure is illustrated by reference to an example instance or a list of example instances, the instance or instances referred to, are by way of non- limiting example instances of the general term, and the general term is not intended to be limited to the specific example instance or instances referred to.
- the word “or” in the description and claims is considered to be the inclusive “or” rather than the exclusive or, and indicates at least one of, or any combination of more than one of items it conjoins.
- FIG. 1 A schematically shows a waveguide combiner 20 optionally comprising a waveguide 30 having two relatively large, parallel face surfaces 31 and 32, edge surfaces 34, and an output coupler 40 comprising an array of parallel, optionally equally spaced facets 42 embedded in the waveguide, in accordance with an embodiment of the disclosure.
- position of features of waveguide combiner 20 may be referenced with respect to x, y, and z axes of a Cartesian coordinate system 100.
- Face surfaces 31 and 32 also referred to as total internal reflecting (TIR) surfaces 31 and 32, are assumed parallel, arbitrarily, to the xy-plane of coordinate system 100. Facets 42 are parallel to and rotated about the x-axis by a tilt angle b in the counterclockwise direction as seen looking along the x-axis towards the yz-plane.
- An input aperture, schematically represented by a dashed rectangle 35 of waveguide 30, is optionally parallel to the xz-plane and an output coupling region of the waveguide, schematically represented by a dashed rectangle 36, is optionally located on face surface 32.
- waveguide combiner 20 comprises a prismatic input coupler 50 for coupling light from virtual images generated by a display engine 70 into waveguide 30 via input aperture 35.
- Output coupler 40 operates to expand input aperture 35 in the y-direction and reflect light from virtual images received through input aperture 35 and propagated in waveguide 30 to the output coupler into an EMB 60 via expanded output coupling region 36 for viewing by a user 102, in accordance with an embodiment of the disclosure.
- user 102 may be represented only by the user’s eye.
- waveguide combiner 20 is shown generating a virtual image schematically represented by a dashed rectangle 72. Natural light from an environment that user 102 sees through waveguide 30 is schematically represented by a block arrow 74.
- Fig. IB shows a schematic cross section of waveguide combiner 20 along a plane A-A indicated in Fig. 1A and propagation of light from virtual image 72 in waveguide 30 for a wFOV supported by the combiner, in accordance with an embodiment of the disclosure.
- FIG. IB schematically shows light from virtual image 72 (Fig. 1A) in a dFOV of display engine 70 illuminating a face surface 51 of input coupler 50, which couples the light into waveguide 30 via input aperture 35, in accordance with an embodiment of the disclosure.
- Input coupler 50, input aperture 35 and a portion of waveguide 30 located in a circle 202 are shown enlarged for ease of viewing and reference in Fig. 1C.
- Angles a’+ and a’ are angles that light rays 81 and 82 (Fig. 1C) that bound the angular extent of dFOV make with a chief ray represented by an arrow 83 of the dFOV.
- Fight rays 81 and 82 and their respective reflections and refractions in waveguide combiner 20 are represented by solid and dashed lines respectively and may be referred to as positive and negative bounding light rays.
- an angle of a light ray from virtual image 72 (Fig. 1A) in plane A- A is considered to be positive or negative if the light ray is rotated respectively clockwise or counterclockwise relative to the chief ray in Fig. IB and figures that follow.
- Chief ray 83 is assumed to be perpendicular to a face surface 51 of input coupler 50 and indices of refraction relative to air of material from which the input coupler and waveguide 30 are made are assumed to be equal to a same index of refraction ng.
- a’+ and a’ are defined as positive and negative angles respectively, and upon entry into input coupler 50 corresponding angles a+ and a. are also defined as positive and negative angles respectively.
- bounding rays 81 and 82 are rotated clockwise relative to chief ray 83 by angles a+ and a. respectively after reflection from face surface 31.
- bounding rays 81 and 82 are rotated respectively counterclockwise relative to chief ray 83 by angles -a+ and -a..
- waveguide 30 As schematically shown in Fig. IB, light rays in wFOV are totally reflected by and bounced back and forth between TIR face surfaces 31 and 32 until they reach and are incident on facets 42 of output coupler 40. At each bounce, a component (not shown) of a light ray in wFOV along a normal “n w ”, to the waveguide reverses direction. As a result, light rays in wFOV after being reflected and bounced off face surface 31 have z-components in the positive z- direction and may be considered as “downward” light rays in the figure propagating downwards from face surface 31 towards face surface 32.
- wFOV When containing downward light rays wFOV is oriented facing downwards, in a positive z-direction. Similarly, light rays after being reflected and bounced off face surface 32 have z-components in the negative z-direction and may be considered as “upward” light rays propagating upwards from face surface 32 towards face surface 31.
- wFOV When facing downwards, wFOV may be distinguished and referenced as wFOV-Down and is labeled in Fig. IB and figures that follow as wFOV-D.
- wFOV when facing upwards, wFOV may be distinguished and referenced as wFOV-Up and is labeled in Fig. IB and figures that follow as wFOV-U.
- the label “wFOV” references wFOV-U and wFOV-D generically.
- facets 42 are configured to have relatively enhanced reflectivity for the corresponding Up-Range or Down-Range incident angles.
- facets 42 are configured to have relatively enhanced transmittance.
- the selected wFOV may be referred to as an image wFOV, and the non-selected wFOV may be referred to as a conjugate wFOV.
- facets 42 are oriented at a relatively small tilt angle P and light rays in wFOV-U and wFOV-D are incident on the facets from opposite sides of the facets.
- wFOV-U is selected as an image wFOV and light rays in wFOV-U are selected to be reflected out of waveguide 30 through output coupling region 36 to provide an output field of view, O-FOV, in EMB 60 for viewing of virtual images generated by display engine 70.
- O-FOV output field of view
- a region of Fig IB indicated by a circle 204 is shown enlarged in Fig. ID.
- the enlarged region 204 in Fig. ID shows an enlarged portion of waveguide 30 comprising facets 42, EMB 60, and O-FOV as seen by user 102, and angles relevant to an embodiment of the disclosure and virtual images such as virtual image 72 provided by display engine 70 that the user sees.
- the figure schematically shows light from upward directed positive and negative bounding light rays 81 and 82 reflected by a given facet 42 in output coupler 40 (Fig. 2A) into EMB 60 as positive and negative bounding output light rays 91 and 92.
- Light rays 91 and 92 delimit output field of view, O-FOV, seen by user 102.
- O-FOV is assumed to have a same angular extent F’ as field of view dFOV (Fig. 1C), which comprises light received by prism input coupler 50 that is introduced by the input coupler into waveguide 30 via input aperture 35.
- Bounding output rays 91 and 92 in waveguide 30 make angles a+ and a. respectively with an output chief ray 93 of O-FOV that is reflected by facet 42 from chief ray 83.
- output rays 91 and 92 also make angles a+ and a. with normal n w of face surfaces 31 and 32. Bounding output rays 91 and 92 are refracted upon entry into EMB 60 to make angles a’+ and a’ respectively with light in output chief ray 93.
- Negative bounding light ray 82 that is incident on facet 42 and from which the facet reflects light into negative bounding output ray 92 makes an angle g_ with respect to normal n w .
- positive bounding light ray 81 that is incident on facet 42 and from which the facet reflects light into positive bounding output ray 91 makes an angle g+ with respect to normal n w .
- Angles g_ and g+ are functions of tilt angle b and of angles a. and a+ respectively, and may be written:
- a light ray in wFOV-U is therefore incident on a facet 42 at an incident angle c
- np normal np
- all rays in wFOV-U be incident on a same side of facets 42 and that all rays in wFOV-D be incident on a same side of facets 42.
- the side on which rays in wFOV-U are incident on facets 42 may in accordance with an embodiment be a same or different side of the facets on which light rays in wFOV-D are incident on the facets.
- waveguide combiner 20 and field of view wFOV are configured so that all the light rays in wFOV-U are incident on a side of facets 42 that faces towards face surface
- waveguide combiner 20 is configured so that for any light ray in wFOV that the waveguide combiner supports, the complement of g is greater than the tilt angle b of facets 42.
- angle g be greater than a critical angle 0 C of waveguide 30, which leads to a second constraint that tilt angle b in combiner 20 satisfy:
- n g is the index of refraction of material from which waveguide combiner 20 is formed.
- reflectivity for light rays in the Up-Range is between about
- Down-Range is less than about 1.5% and is optionally less than about 1%.
- An angular “See-Thru” range for environmental, natural light 74 (Fig. 1A) incident on the facets advantageously extends from about 5° to about 45° and exhibits substantially achromatic transmittance greater than or equal to about 85%.
- Fig. IE shows a graph 210 of reflectivity for facets 42 that may be manufactured to substantially accord with the numerical specifications discussed above.
- the graph comprises a reflectivity curve 212 that gives reflectivity of facets 42 in waveguide 30 as a function of incident angle of light on the facets. Reflectivity in percent is shown along an ordinate of graph 210, and angle of incidence of light on facets 42 is shown along the abscissa.
- the Up-Range of incident angles selected to be the image wFOV and reflectivity angular range is schematically represented by a shaded region 218.
- the Down-Range of incident angles selected to be the transmittance angular range and conjugate wFOV is schematically represented by a shaded region 216.
- a dashed hat function 214 indicates the “See-Thru”, angular range of the facets for natural light 74 (Fig. 1A), in accordance with an embodiment of the disclosure.
- facets 42 are designed so that reflectivity of the facets is relatively constant as a functions of wavelength for the Up-Range and Down-Range of incident angles for each R, G, B lasing bandwidth at which the UDs are expected to lase.
- variance of reflectivity of the facets with wavelength in respective R, G, and B facet wavelength bands is less than 5%. In an embodiment the variance is less than 2%.
- UDs typically lase at wavelengths in a relatively narrow wavelength band of between 1 - 2 nm (nanometers) FWHM (full width half max).
- a ED lasing bandwidth may shift for example, by as much as O.lnm to 0.35nm per degree Celsius (°C) change in LD operating temperature, and operating temperatures may easily change by as much as 20°C.
- manufacturing tolerances may allow as much as a 5 nm variance in a central lasing wavelength at which LDs of a same type lase.
- facets 42 are advantageously configured to have a facet wavelength band for each of R, G, and B light produced by the LDs for the Up-Range and Down-Range angles of incidence equal to or greater than about 20 nm.
- reflectivity for wavelengths in the band varies by less 3% of an average reflectivity to provide a color gamut chromaticity discrepancy radius “ACG” in a CIE 1931 xy chromaticity space that is less than or equal to about 0.02.
- Fig. IF schematically shows lasing bandwidths 120R, 120G, and 120B for R, G, and B lasing bandwidths of LDs in display engine 70 and corresponding facet wavelength bands 121RW, 121GW, 121BW, for facets 42, in accordance with an embodiment of the disclosure.
- Fig. 1G shows a graph 230 of a curve 232 that gives reflectivity of facets 42 as a function of wavelength for a span of blue wavelengths in the visible spectrum.
- a portion of curve 232 is magnified in an inset 234 and is marked to show a region of the curve centered at a blue wavelength of about 450nm between about 445nm to about 455nm that graphs reflectivity as a function of wavelength in facet wavelength band 121BW.
- Reflectivity of facets 42 for wavelengths in facet wavelength band 121BW is equal to about 4.8% and varies for wavelengths in the wavelength band by less than about 5%.
- Facets 42 having reflectivity for incident angle See-Thru range, Up-Range, and Down- Range shown in Fig. IE, and R, G, B facet wavelength bands shown in Fig. IF may comprise partially reflecting dielectric mirrors.
- the partially reflecting dielectric mirrors may be manufactured by depositing partially reflecting coatings on surfaces of preformed prisms and bonding the prisms together.
- the prisms may be fabricated by grinding and polishing a silicate material, such as BK-7, to a desired shape, or by injection molding a suitable polymer or sol-gel.
- Fig. 2A schematically shows another waveguide combiner 320, in accordance with an embodiment of the disclosure.
- Waveguide combiner 320 is similar to waveguide combiner 20 and has wFOV-U and wFOV-D selected for image wFOV and conjugate wFOV respectively.
- waveguide combiner 320 comprises a waveguide 330 having facets 342 that are tilted at a tilt angle P that is larger than the tilt angle of facets 42 in waveguide combiner 20.
- waveguide combiner 320 is configured so that light rays in both wFOV- D and wFOV-U are incident on a same side of facets 242, that is the side facing TIR face surface 32.
- waveguide combiner 320 To provide the same side incidence exhibited by waveguide combiner 320 calculations similar to those performed form waveguide combiner 20 lead to the following constraints for waveguide combiner 320. For all g,
- Down-Range ⁇ nf ⁇
- equal to about 13°, and F' having a diagonal extent of about 30° and an aspect ratio of 16:9, b may equal about 35°.
- the Up-Range, reflectivity angular range, of incident angles selected as the image wFOV advantageously extends from about 26° to about 44° and is characterized by an average reflectivity optionally between about 9% and 11%, optionally equal to or greater than 10%.
- the Down-Range, transmittance angular range, selected for the conjugate wFOV extends advantageously from about 66° to about 84° and is characterized by an average reflectivity less than or equal to about 5%, and optionally equal to or less than 2%.
- a See-Thru range advantageously extends from about 15° to about 55° and is characterized by a transmittance equal to or greater than about 85%.
- Fig. 2B shows a graph 350 of reflectivity for facets 242 that may be manufactured optionally similarly to the way facets 42 are manufactured, to substantially accord with the numerical specifications discussed above.
- the graph comprises a reflectivity curve 312 that gives reflectivity of facets 242 in waveguide 330 as a function of incident angle of light on the facets. Reflectivity in percent is shown along an ordinate of graph 351, and angle of incidence of light on facets 242 is shown along the abscissa.
- the Up-Range of incident angles selected to be the image wFOV and reflectivity angular range is schematically represented by a shaded region 351.
- the Down-Range of incident angles selected to be the transmittance angular range and conjugate wFOV is schematically represented by a shaded region 352.
- a dashed hat function 353 indicates the “See-Thru”, angular range of the facets for natural light 74 (Fig. 1A), in accordance with an embodiment of the disclosure.
- FIG. 3 A schematically shows another waveguide combiner 420, in accordance with an embodiment of the disclosure.
- Waveguide combiner 420 is similar to waveguide combiner 320 shown in Fig. 2A but comprises a waveguide 430 having facets 442 that are tilted at a tilt angle b that is larger than the tilt angle of facets 342 in combiner waveguide 330.
- waveguide combiner 420 is configured, as is waveguide combiner 320, so that light rays in both wFOV-D and wFOV-U are incident on a same side of facets 342 (the side facing face surface 32), in waveguide combiner 420, unlike in waveguide combiner 320, wFOV-D is the image wFOV and wFOV-U is the conjugate wFOV.
- the angular Up-Range, which is the transmittance range, and the Down-Range, which is the reflectivity range, for waveguide combiner 420 may be written,
- Up-Range ⁇ Vc
- Fig. 3B provides a graph 450 that shows the angular locations and extents of the Up-Range (transmittance range) 451 Down-Range (reflectance range) 452 and See-Thru range 453 for facets 442 in waveguide 430.
- equal to about 13°, and F' having a diagonal extent of about 30° and an aspect ratio of 16:9, b may be equal to 63.5°.
- the Up-Range, transmittance angular range of incident angles advantageously extends from about 2° to about 20° and has a relatively low average reflectivity advantageously less than about 5% and optionally less than or about equal to 2.0% .
- the Down-Range, selected for the reflective angular range and image wFOV advantageously extends from about 55° to about 75° and has a relatively high average reflectivity between about 9% and about 11% and optionally greater than or equal to 10%.
- Thru range advantageously extends from about 40° to about 80° and is characterized by a transmittance equal to or greater than about 85%.
- Fig. 3B shows a graph 450 of reflectivity for facets 342 that may be manufactured optionally similarly to the way facets 42 are manufactured, to substantially accord with the numerical specifications discussed above.
- the graph comprises a reflectivity curve 412 that gives reflectivity of facets 342 in waveguide 430 as a function of incident angle of light on the facets. Reflectivity in percent is shown along an ordinate of graph 351, and angle of incidence of light on facets 342 is shown along the abscissa.
- the Up-Range of incident angles selected to be the conjugate wFOV and transmittance angular range is schematically represented by a shaded region 451.
- the Down-Range of incident angles selected to be the reflectance angular range and image wFOV is schematically represented by a shaded region 452.
- a dashed hat function 453 indicates the See-Thru, angular range of the facets for natural light 74 (Fig. 1A), in accordance with an embodiment of the disclosure.
- v u represent a normalized vector in the propagation direction of an upward light ray that is contained in a wFOV-U in waveguide 30, 330, or 430 of waveguide combiner 20, 320, or 420, but not necessarily in the plane A-A respectively shown for the waveguide combiner in Figs. IB, 2B, or 3B.
- )L1 of the upward light ray on a facet of the waveguide relative to the normal to the facet may be given by an expression
- f p cos _ 1 (v u -nf), where np is the vector normal to the facet.
- Up-Range ⁇ V3 ⁇ 4(-180° + 3b + a.) ⁇ cos l(v u -np) ⁇ (-180° + 3b + a+) ⁇ ;
- each facet in a combiner waveguide in accordance with an embodiment is designed to have reflectivity and transmittance angular ranges for each of R, G, and B light.
- practice of an embodiment of the disclosure is not limited to facets that have angular ranges for each of R, G, and B light.
- a facet in accordance with an embodiment may be designed to function for colors different than R, G, and B, and may be configured to function for more or less than three colors.
- each facet may be designed to function for only one, or only two of R, G, or B .
- L is a length of a facet between TIR faces and h is a coefficient, typically less than one, may for example advantageously be different from that shown in Figs. IB, 2A, or 3A.
- a smaller pitch P may be advantageous to provide spatial integrity to virtual images provided by a waveguide combiner in accordance with an embodiment.
- Waveguide combiners discussed above by way of examples expand input aperture 35 in one direction along the y-axis (as shown for example in Fig. 1A) in accordance with an embodiment of the disclosure.
- a waveguide combiner that expands an input aperture along two directions, for example the x-direction as well as the y-direction, may be provided by replacing input coupler 50 in the waveguide combiner shown in Fig. 1A with a waveguide combiner that expands an input aperture in the x-direction, in accordance with an embodiment of the disclosure.
- FIG. 4 schematically shows a waveguide combiner 500 that expands an input aperture 535 in two, optionally orthogonal, directions to provide an expanded output coupling region 536 through which the waveguide combiner directs light into an EMB 560, in accordance with an embodiment of the disclosure.
- Waveguide combiner 500 optionally comprises a prismatic input coupler 550 a first waveguide 530 and a second waveguide 630, in accordance with an embodiment of the disclosure.
- Input coupler 550 receives light from virtual images generated by a laser display engine 570 through input aperture 535 and inputs the light into waveguide 530.
- Waveguide 530 comprises first and second TIR face surfaces 531 and 532 respectively that are parallel, arbitrarily, to the xy- plane of coordinate system 100, and top and bottom surfaces 532 and 534.
- the waveguide has an output coupler 540 comprising a plurality of parallel facets 542 in accordance with an embodiment of the disclosure.
- the facets are perpendicular to face surfaces 531 and 532 and are rotated about the z-axis by a tilt angle b*.
- the facets are evenly spaced.
- Light rays in light received from input coupler 550 are repeatedly totally reflected by and bounced back and forth between TIR face surfaces 531 and 532 until they reach and are incident on facets 542 of output coupler 540.
- Facets 542 are distributed over a relatively extended distance in the x-axis direction and reflect the light rays out of waveguide 530 in a general direction of the minus y-axis and into waveguide 630 through an extended output aperture 545 that expands input aperture 535 in the x-direction.
- Waveguide 630 may be any waveguide configured to receive light from an image generated by a display engine via an input aperture such as input aperture 535 and project the received light out from the waveguide via an output coupling region such as output coupling region 545 that is expanded substantially in a single direction.
- Waveguide 630 is assumed by way of example to be similar to waveguide 30, comprises facets 42 and TIR face surfaces 31 and 32 that are parallel to the xy-plane and are optionally continuous with face surfaces 531 and 532 respectively.
- Waveguide 630 expands the image in 545 of waveguide 530 in the minus y-direction and reflects the light it receives from waveguide 530 through an output coupling region 536 extended in both the x and y directions into EMB 560. It is noted that whereas waveguide 630 is assumed similar to waveguide 30 shown in Fig. 1A, waveguide 630 may be similar to any of various waveguides, for example waveguide 330 (Fig. 2A) or waveguide 430 (Fig. 3 A) comprising facets and configured in accordance with an embodiment of the disclosure.
- Equations 25) and 26) may be chained to relate desired constraints on an output field of view that waveguide combiner 500 provides for EMB 560.
- Fet upward and downward directed light rays propagating in waveguide 530 relative to face surfaces 531 and 532 be represented by vectors v u (530) and v d (530). then
- v d (630) (v u (630) -(2v u (630).n w )n w , where n w is a normal to face surfaces 531, 532, 31, and 32 in waveguide combiner 500 and upward and downward directed light rays are arbitrarily considered to be traveling in the minus and plus z-directions respectively.
- n w is a normal to face surfaces 531, 532, 31, and 32 in waveguide combiner 500 and upward and downward directed light rays are arbitrarily considered to be traveling in the minus and plus z-directions respectively.
- One of the upward and down directed groups of light rays propagating in waveguide 530 is reflected by facets 542 into waveguide 630.
- v u (530) light rays are reflected into waveguide 630.
- v u (630) v u (530) -2(v u (530) -nf(542)nf.
- v d (630) v u (630)-2(v u (630).n w )n w .
- Upward and downward directed light rays in waveguide 630 are contained respectively in upward and downward directed fields of view wFOV-U and wFOV-D as schematically shown in Figs. 1A, 2A, and 3A. And in accordance with an embodiment, light rays in one of wFOV-U and wFOV-D in waveguide 630 are selected for reflection by facets 42 through output coupling region 536 in an output field of view O-FOV into EMB 560. Desired constraints on light rays in O-FOV may be back propagated to harmonize tilt angles b and b* that characterize facets 42 and 542 in waveguides 30 and 530.
- each of the verbs, “comprise” “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of components, elements or parts of the subject or subjects of the verb.
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Abstract
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Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
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CN202180013816.6A CN115104059A (en) | 2020-02-24 | 2021-02-22 | Mixed reality combiner |
JP2022543019A JP2023514807A (en) | 2020-02-24 | 2021-02-22 | mixed reality combiner |
US17/776,126 US20220397766A1 (en) | 2020-02-24 | 2021-02-22 | Mixed reality combiner |
KR1020227027843A KR20220136367A (en) | 2020-02-24 | 2021-02-22 | mixed reality combiner |
IL294538A IL294538A (en) | 2020-02-24 | 2021-02-22 | Mixed reality combiner |
EP21761635.8A EP4042233A4 (en) | 2020-02-24 | 2021-02-22 | Mixed reality combiner |
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US202062980469P | 2020-02-24 | 2020-02-24 | |
US62/980,469 | 2020-02-24 | ||
US202063001567P | 2020-03-30 | 2020-03-30 | |
US63/001,567 | 2020-03-30 |
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PCT/IL2021/050206 WO2021171289A1 (en) | 2020-02-24 | 2021-02-22 | Mixed reality combiner |
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US (1) | US20220397766A1 (en) |
EP (1) | EP4042233A4 (en) |
JP (1) | JP2023514807A (en) |
KR (1) | KR20220136367A (en) |
CN (1) | CN115104059A (en) |
IL (1) | IL294538A (en) |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11668933B2 (en) | 2020-11-09 | 2023-06-06 | Lumus Ltd. | Color corrected back reflection in AR systems |
US11796729B2 (en) | 2021-02-25 | 2023-10-24 | Lumus Ltd. | Optical aperture multipliers having a rectangular waveguide |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2010029076A2 (en) | 2008-09-11 | 2010-03-18 | Nestec S.A. | Method of promoting and selling coffee |
US8665178B1 (en) * | 2012-03-01 | 2014-03-04 | Google, Inc. | Partially-reflective waveguide stack and heads-up display using same |
WO2017141242A2 (en) * | 2016-02-18 | 2017-08-24 | Beamus Ltd. | Compact head-mounted display system |
US20190056600A1 (en) * | 2016-12-31 | 2019-02-21 | Lumus Ltd | Eye tracker based on retinal imaging via light-guide optical element |
WO2019077601A1 (en) * | 2017-10-16 | 2019-04-25 | Oorym Optics Ltd. | Highly efficient compact head-mounted display system |
-
2021
- 2021-02-22 WO PCT/IL2021/050206 patent/WO2021171289A1/en unknown
- 2021-02-22 IL IL294538A patent/IL294538A/en unknown
- 2021-02-22 KR KR1020227027843A patent/KR20220136367A/en active Search and Examination
- 2021-02-22 EP EP21761635.8A patent/EP4042233A4/en active Pending
- 2021-02-22 US US17/776,126 patent/US20220397766A1/en active Pending
- 2021-02-22 CN CN202180013816.6A patent/CN115104059A/en active Pending
- 2021-02-22 JP JP2022543019A patent/JP2023514807A/en active Pending
- 2021-02-24 TW TW110106564A patent/TW202138852A/en unknown
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2010029076A2 (en) | 2008-09-11 | 2010-03-18 | Nestec S.A. | Method of promoting and selling coffee |
US8665178B1 (en) * | 2012-03-01 | 2014-03-04 | Google, Inc. | Partially-reflective waveguide stack and heads-up display using same |
WO2017141242A2 (en) * | 2016-02-18 | 2017-08-24 | Beamus Ltd. | Compact head-mounted display system |
US20190056600A1 (en) * | 2016-12-31 | 2019-02-21 | Lumus Ltd | Eye tracker based on retinal imaging via light-guide optical element |
WO2019077601A1 (en) * | 2017-10-16 | 2019-04-25 | Oorym Optics Ltd. | Highly efficient compact head-mounted display system |
Non-Patent Citations (2)
Title |
---|
HIROSHI MUKAWA, KATSUYUKI AKUTSU, IKUO MATSUMURA, SATOSHI NAKANO, TAKUJI YOSHIDA, MIEKO KUWAHARA, KAZUMA AIKI: "A full-color eyewear display using planar waveguides with reflection volume holograms", JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY - SID, 1 January 2009 (2009-01-01), pages 185 - 193, XP055448169, ISSN: 1071-0922, DOI: 10.1889/JSID17.3.185-187 * |
See also references of EP4042233A4 |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11668933B2 (en) | 2020-11-09 | 2023-06-06 | Lumus Ltd. | Color corrected back reflection in AR systems |
US11796729B2 (en) | 2021-02-25 | 2023-10-24 | Lumus Ltd. | Optical aperture multipliers having a rectangular waveguide |
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US20220397766A1 (en) | 2022-12-15 |
CN115104059A (en) | 2022-09-23 |
TW202138852A (en) | 2021-10-16 |
JP2023514807A (en) | 2023-04-11 |
EP4042233A1 (en) | 2022-08-17 |
KR20220136367A (en) | 2022-10-07 |
EP4042233A4 (en) | 2022-11-23 |
IL294538A (en) | 2022-09-01 |
WO2021171289A8 (en) | 2022-11-17 |
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