Near-eye 3d display with separated phase and amplitude modulators

Abstract

Augmented reality glasses include a near-eye display including an image amplitude modulated light optical source coupled with a spatial phase modulator or active area plate modulator and optically coupled with eye coupling optics. The image amplitude modulated light source may include a light emitting 2D display panel or a light source coupled to an image amplitude modulator. The eye coupling optics may include a volume holographic diffraction grating.

Description

[0001] This application is a divisional application of a patent application with international application number PCT / US2018 / 052882, international application date September 26, 2018, Chinese national application number 201880062496.1, and title “Near-Eye 3D Display with Separated Phase and Amplitude Modulators”. Technical Field

[0002] The present invention relates to near-eye displays. More particularly, the present invention relates to near-eye three-dimensional (3D) displays. Background Art

[0003] Since the advent of smartphones, the public has widely realized the tremendous utility of having a versatile and always-available device capable of general computing and multimedia communications. Nevertheless, a significant disadvantage of smartphones is the relatively small screen size. Smartphone displays are only a fraction of the size of a small laptop screen.

[0004] It is now expected that smartphones will eventually be replaced or indispensably enhanced by augmented reality glasses, which will, among other things, effectively provide the user with a relatively large field-of-view 3D image output system that the user can access at will, whether for business or entertainment purposes.

[0005] Not only will the screen size exceed what a laptop can afford and without the hassle of carrying a laptop, augmented reality glasses will also provide new mixed reality applications that seamlessly integrate real-world and virtual content. This will not only keep the user connected to the real world, thereby preventing the social withdrawal from real-world interactions sometimes associated with excessive smartphone use, but will also enable new types of augmentations to the physical world, such as: automatically generated contextually relevant information superimposed on automatically identified real-world objects; communication between remote persons through 3D avatars of each party displayed to the other party; and mixed reality games that include virtual content that behaves realistically, such as respecting the boundaries of physical objects in the real world. Summary of the invention

[0006] One aspect of augmented reality glasses is to display virtual content through a transparent eyepiece. One type of transparent eyepiece is based on a waveguide that includes a transparent diffractive optical element for controlling the propagation of light carrying a virtual image. One problem with such waveguide eyepieces is their inefficiency in transmitting the light carrying the virtual image to the user's eye. This inefficiency results in higher power consumption, and thus shorter battery life and associated thermal management requirements.

[0007] Additionally, to enhance the realism of virtual content, it is desirable to display the content at different depths. Properly displaying content at a distance from the user requires bending the wavefront of the light used to generate the virtual image of the content. The curvature is inversely related to the virtual image distance. In order to achieve multiple virtual image distances when using a waveguide-based eyepiece, a stack of waveguides is used, each with a different outcoupling optical component. The latter approach effectively limits the virtual distances that can be provided to a small, finite number, e.g., 2 selected distances.

[0008] The embodiments described herein improve the efficiency of coupling 3D images through the optical component train and to the user's eyes, and are more comprehensive in being able to control the depth of the virtual image.

[0009] Embodiments of the present invention provide augmented reality glasses including a near-eye display, the near-eye display including an image intensity modulated light source coupled to a spatial phase modulator, the spatial phase modulator can apply a spatially varying phase modulation across a light beam received by the image intensity modulated light source. The spatial phase modulator is also coupled to an eye coupling optical component. The image amplitude modulated light source can take the form of a light source coupled to a 2D pixelated amplitude modulator (e.g., a liquid crystal on silicon (LCoS) modulator or a digital micromirror device (DMD) modulator), or a light-emitting 2D display panel (e.g., an organic light-emitting diode (OLED) display panel). The spatial phase modulator can also take the form of an LCoS modulator. The eye coupling optical component can take the form of an off-axis volume holographic diffraction grating that receives light at a relatively high angle of incidence compared to the angle at which the light is redirected to the user's eye, thereby allowing a portion of the near-eye display to be positioned on one side of the user's eye. In some embodiments, the light path between the light source and the eye coupling optical component can reach the amplitude modulator before reaching the spatial phase modulator. The near-eye display can further include a beam splitter disposed between the amplitude modulator and the spatial phase modulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings illustrate the design and utility of the preferred embodiments of the present invention, wherein similar elements are referenced by common reference numerals. In order to better understand how to obtain the above and other advantages and purposes of the present invention, a more specific description of the present invention described above will be presented by referring to the specific embodiments of the present invention shown in the accompanying drawings.

[0011] Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

[0012] Figure 1 is a block diagram of a near-eye display according to some embodiments of the present invention;

[0013] Figure 2is a block diagram of a near-eye display according to some embodiments of the present invention;

[0014] Figure 3 A pair of augmented reality glasses according to some embodiments of the present invention are shown;

[0015] Figure 4 is a schematic diagram of a near-eye display having a transmissive image amplitude modulator and a transmissive phase modulator according to some embodiments of the present invention;

[0016] Figure 5 is a schematic diagram of a near-eye display having a reflective amplitude modulator and a reflective phase modulator according to some embodiments of the present invention;

[0017] Figure 6 is a schematic diagram of a near-eye display having a transmissive amplitude modulator and a reflective phase modulator according to some embodiments of the present invention;

[0018] Figure 7 is a schematic diagram of a near-eye display having a reflective amplitude modulator and a transmissive phase modulator according to some embodiments of the present invention;

[0019] Figure 8 is a schematic diagram of a near-eye display including a beam splitter between an LCoS amplitude modulator and an LCoS phase modulator according to some embodiments of the present invention;

[0020] Fig. 9 is a schematic diagram of a near-eye display including a prism pair between a DMD light modulator and an LCoS phase modulator according to some embodiments of the present invention;

[0021] Fig.10 is a schematic diagram of a near-eye display including an OLED source of image amplitude modulated light and a beam splitter between a phase modulator according to some embodiments of the present invention;

[0022] Fig.11 is a block diagram of a near-eye display system according to some embodiments of the present invention;

[0023] Fig.12 is an illustration of a Fresnel lens that may be formed on a spatial phase modulator according to some embodiments of the present invention;

[0024] Fig.13 is an illustration of a Fresnel lens that may be formed on a spatial phase modulator and shifted laterally from a center to deflect light along a path to a user's eye, according to some embodiments of the present invention;

[0025] Fig.14 According to some embodiments of the present invention Figure 2A depiction of an area plate lens formed on an active area plate modulator included in the illustrated display;

[0026] Fig.15 According to some embodiments of the present invention, Figure 2 a diagrammatic representation of a grid of area plate patterns formed on an active area plate modulator included in the illustrated display; and

[0027] Fig.16 is a schematic diagram of the operation of some embodiments of the present invention. DETAILED DESCRIPTION

[0028] Figure 1 is a block diagram of a near-eye display 100 according to some embodiments of the present invention. Figure 1 As shown, the near-eye display 100 includes an image amplitude modulated light source 102. As shown, the image amplitude modulated light source 102 includes a coherent light source 104 (e.g., one or more laser diodes (LDs)) and an image amplitude modulator 106. The image amplitude modulator 106 may include, for example, an LCoS modulator, a DMD modulator, or a transmissive liquid crystal modulator. Figure 2 The replacement shown, such as Figure 1 As shown, the image amplitude modulated light source may take the form of a pixelated light emitting display panel, such as an OLED display panel or a micro LED display panel.

[0029] The image amplitude modulated light source 102 is optically coupled to a spatial phase modulator 108. In this specification, the term "optically coupled" may include propagation along an optical path, which may include: free space and / or one or more optical elements, such as, for example, lenses, reflectors, and light pipes. The spatial phase modulator 108 may, for example, include a zero-twist electrically controlled birefringent liquid crystal (ZTECBLC) modulator. The spatial phase modulator 108 may be configured as a single Fresnel lens configuration, including a configuration of a grid of Fresnel lenses, or a superposition of multiple Fresnel lenses in a non-grid configuration. A single Fresnel lens configuration may be used to impart a common wavefront curvature to all light received from the image amplitude modulated light source 102. Grids of Fresnel lenses and non-grid multiple Fresnel lens configurations may be used to impart different wavefront curvatures to different regions of light received from the image amplitude modulated light source. In each case, the wavefront curvature is the inverse of the virtual image distance. Setting the wavefront curvature to the inverse of the virtual image distance helps to create a more realistic impression that the virtual image output by the image amplitude modulator 106 is at the virtual image distance relative to the user's position.

[0030] The spatial phase modulator 108 is optically coupled to the eye coupling optics. The eye coupling optics may, for example, take the form of a holographic volume diffraction grating or a mirrored eyepiece comprising refractive and / or reflective surfaces. The image amplitude modulated light and the spatial phase modulated light may correspond to the amplitude and phase modulated components of a hologram (e.g., a computer generated hologram).

[0031] Figure 2 2 is a block diagram of a near eye display 200 according to some embodiments of the present invention. The display system includes an image amplitude modulated light source 202, which includes a light source 204 optically coupled to an image amplitude modulator 206. The light source 204 may, for example, include a light emitting diode (LED) or LD. Any other suitable light source may be used.

[0032] The image amplitude modulated light source 202 is optically coupled to an active zone plate modulator 208. The active zone plate modulator 208 can reconfigurably form a zone plate of varying focal length by presenting a zone plate pattern including alternating bright and dark rings. The active zone plate modulator 208 can be a reflective light modulator or a transmissive light modulator. The active zone plate modulator can be implemented using, for example, a DMD modulator, an LCoS modulator, or a transmissive liquid crystal (LC) modulator. The active zone plate modulator 208 can be used to present a single zone plate pattern, a grid of multiple zone plate patterns, or a non-grid superposition of zone plate patterns. A single zone plate pattern can be used to impart a wavefront curvature to the image modulated light received from the image amplitude modulated light source 202. On the other hand, multiple zone plate patterns can be used to impart different wavefront curvatures to different portions of the image modulated light received from the image amplitude modulated light source 202. In each case, the wavefront curvature corresponds to an inverted virtual image distance image presented by the near eye display 200. The depth perception of an image presented by a near-eye display system is enhanced by bending the wavefront of light used to present the image based on a predetermined distance to virtual content (e.g., animate and inanimate objects) in the presented image. Where multiple zone plate patterns are implemented, a first portion of image modulated light carrying an image of a first virtual object (e.g., a book) may be diverged by a first zone plate pattern to have a first curvature corresponding to an inverse of a first desired distance to the first virtual object, and a second portion of image modulated light carrying a second virtual object (e.g., an avatar) may be diverged by a second zone plate pattern to have a second curvature corresponding to an inverse of a second desired distance to the second virtual object. The active zone plate modulator 208 is coupled to the eye coupling optical component 210.

[0033] Figure 3A pair of augmented reality glasses 300 according to an embodiment of the present invention is shown. The augmented reality glasses 300 include a left temple 302 and a right temple 304 connected to a front frame portion 306. A left volume holographic diffraction grating eyepiece 308 and a right volume holographic diffraction grating eyepiece 310 are mounted in the front frame portion 306. A left 3D image generator 312 is mounted on the left temple 302, and a right 3D image generator 314 is mounted on the right temple 304. The left 3D image generator 312 includes a left protective optical window 316, and the right 3D image generator 314 includes a right protective optical window 318. The left eye position 320 and the right eye position 322 of the user are schematically shown. The left eyepiece 308 is configured to reflect (or otherwise redirect) light from the left 3D image generator 312 to the left eye position 320, and the right eyepiece 310 is configured to reflect (or otherwise redirect) light from the right 3D image generator 314 to the right eye position. The left and right 3D image generators 312, 314 may each include the image amplitude modulated light source 102 in combination with the spatial phase modulator 108, or may include the image amplitude modulated light source 202 in combination with the active area plate modulator 208. The left and right volume holographic diffraction grating eyepieces 308, 310 are possible embodiments of the eye coupling optics 110 and the eye coupling optics 210. The left eye tracking camera 324 and the right eye tracking camera 326 are mounted on the front frame portion 306.

[0034] The virtual content displayed using the left and right image generators 312, 314 may include one or more virtual objects at different depths. The eye tracking cameras 324, 326 may be used to determine which particular virtual object the user is viewing. Based on the desired depth of the particular virtual object the user is viewing, the spatial phase modulator 108 or the active area plate modulator 208 may be used to form a negative power lens that imparts a divergent (convex toward the user) wavefront curvature to the light from the image amplitude modulated light source 102 or 202. The radius of curvature of the light is appropriately set to be equal to the depth of the particular virtual object the user is viewing (as determined by the eye tracking cameras 324, 326). The depth of each particular virtual object may be determined by one or more programs, such as an augmented reality program that generates the virtual object. In addition, the negative lens pattern formed by the spatial phase modulator 108 or the active area plate modulator 208 may be moved laterally to deflect the light so that after being redirected by the eyepieces 308, 310, the light will be incident on the user's pupil.

[0035] refer to Fig.12, shows a diffractive Fresnel lens pattern 1200 that may be formed by the spatial phase modulator 108 of the display 100. The diffractive Fresnel lens pattern 1200 is described in terms of focal length. The diffractive Fresnel lens pattern may be generated in response to detecting, using the eye tracking camera 324326, that a user is viewing virtual content located at a depth (distance from the user) equal to the focal length. The focal length may be changed as desired depending on the distance between the user and the virtual content that the user is viewing. The focal length of the diffractive Fresnel lens pattern may be adjusted as the user changes the direction of their gaze so that the resulting wavefront curvature will correspond to the distance associated with the virtual content that the user is currently viewing.

[0036] refer to Fig.13 , a second Fresnel lens pattern 1300 is shown. The second lens pattern 1300 is laterally shifted relative to the centered first Fresnel lens pattern. The second Fresnel lens pattern is laterally shifted based on the movement of the user's eye position determined by the eye tracking cameras 324, 326 so as to deflect light along the light path (including redirection by the eyepieces 308, 310) to be suitable for viewing by the user. The Fresnel lens pattern 1300 can be moved in any direction so as to track the user's gaze and couple into the user's eye through the pupil. In some embodiments, the position movement of one or more Fresnel lens patterns corresponds to the movement of the user's gaze direction determined by the eye tracking cameras 324, 326.

[0037] refer to Fig.14 , a negative area plate pattern 1400 is shown. The negative area plate pattern 1400 may be formed on the active area plate modulator 208 and may be used in place of the negative diffraction Fresnel pattern 1200 to cause the wavefront of light received from the image amplitude modulated light source 202 to have a radius of curvature that is based on (e.g., equal to) the distance to the virtual object being viewed by the user as determined by the eye tracking cameras 324, 326. The negative area plate pattern 1400 may also be moved laterally based on information obtained from the eye tracking cameras 324, 326 about the position of the user's pupil to deflect light to the user's pupil.

[0038] Those skilled in the art will appreciate that while the present disclosure relates to tracking the user's pupil in a particular embodiment, other anatomical eye imaging or positioning may be used. For example, retinal images may be obtained and aggregated over time to provide a retinal map, where any single retinal image obtained by the eye tracking cameras 324, 326 at a given time corresponds to the gaze direction of the eye. That is, as the pupil changes gaze direction, it will provide a variable position aperture through which the eye tracking cameras 324, 326 will receive image data of the retina, the variable position of which corresponds to the new gaze direction.

[0039] refer to Fig.15, a grid of four plate patterns 1500 is shown, including an upper left plate pattern 1502, an upper right plate pattern 1504, a lower left plate pattern 1506, and a lower right plate pattern 1508. In this example configuration, the upper left plate pattern 1502 and the lower left plate pattern 1506 are identical, and the upper right plate pattern 1504 and the lower right plate pattern 1508 are different. Each particular plate pattern of the four plate patterns 1502, 1504, 1506, 1508 has a negative focal length that is related to (e.g., equal to) a distance to a particular virtual object or portion of a virtual scene that is presented with intensity / amplitude modulated light emitted from an image modulated light source 102, 202 incident on the particular plate pattern (e.g., 1502, 1504, 1506, 1508). Thus, for example, an image of a virtual bee may be coupled via one of the panel patterns 1502, 1504, 1506, 1508 in the grid 1500, and an image of a virtual butterfly may be coupled via another of the panel patterns 1502, 1504, 1506, 1508 in the grid 1500. Fig.15 Not shown, however, as with the Fresnel lens 1300, each of the plate patterns 1502, 1504, 1506, 1508 may be moved based on the movement of the user's pupil so as to direct light into the user's pupil and ensure that the corresponding virtual object is aligned with the plate pattern.

[0040] Fig.161 is a schematic diagram of the operation of certain embodiments of the present invention. An optical amplitude modulator 1602 modulates light to present three virtual objects. A first portion 1604 of the amplitude modulated light is used to present a first virtual object, a second portion 1606 of the amplitude modulated light is used to present a second virtual object, and a third portion 1608 of the amplitude modulated light is used to present a third virtual object. Each of the three portions 1604, 1606, 1608 of the amplitude modulated light has a limited divergence angle. The limited divergence angle may be attributed to the high degree of collimation of the light illuminating the optical amplitude modulator (e.g., laser) and the limited degree to which the optical amplitude modulator 1602 increases the divergence of the light. The optical amplitude modulator 1602 may include pixels that generate an exiting light cone, the divergence of which may have an upper and / or lower limit imposed by the inclusion of divergent, diffractive, and / or reflective or transmissive diffusive optical materials of the incident illumination. The first, second, and third portions 1604, 1606, 1608 of the amplitude modulated light are incident on first, second, and third Fresnel lens patterns 1610, 1612, 1614, respectively, which may be dynamically formed on the phase modulator 1616. Each of the dynamically formed Fresnel lens patterns 1610, 1612, 1614 has a focal length selected to impart a particular light field curvature to the first, second, and third portions 1604, 1606, 1608 of the amplitude modulated light. The dynamically formed Fresnel lens patterns 1610, 1612, 1614 may have a positive focal length or a negative focal length depending on the divergence of the portions 1604, 1606, 1608 of the amplitude modulated light reaching the phase modulator 1616. However, in general, after interacting with the phase modulator 1616, the light will diverge (rather than converge) with a radius of curvature related to the distance of the virtual object. Note that in some embodiments, the eyepieces 308, 310 may have optical refractive power, in which case the wavefront curvature of the light reaching the user's eye positions 320, 322 is a function of the optical refractive power of the eyepieces 308, 310 and the optical refractive power of the dynamically formed Fresnel lens patterns 1610, 1612, 1614. In the latter case, the light leaving the phase modulator 1616 may converge. Fig.16 As shown on the right side of , the first portion 1618 of the wavefront curvature controlled light is formed by the first portion 1604 of the amplitude modulated light through the action of the first dynamically formed Fresnel lens pattern 1610. Similarly, the second portion 1620 of the wavefront curvature controlled light is formed by the second portion 1606 of the amplitude modulated light through the action of the second dynamically formed Fresnel lens 1612. The third portion 1622 of the wavefront curvature controlled light is formed by the third portion 1608 of the amplitude modulated light through the action of the third dynamically formed Fresnel lens 1614. Figure 3In the case of the illustrated embodiment, the three portions 1618, 1620, 1622 of the wavefront curvature control light are optically coupled to the user's eye positions 320, 322 via the volume holographic diffraction grating eyepiece. Alternatively, other types of eyepieces may be used to couple the three portions 1618, 1620, 1622 of the wavefront curvature control light to the user's eye positions. Fig.16 Three virtual objects displayed at three virtual depths are shown, but other embodiments are possible. For example, one or more virtual objects may be displayed at one or more depths using one or more portions of amplitude modulated light formed by the action of one or more dynamically formed Fresnel lenses. In some embodiments, one Fresnel lens may be used to determine the depth of one virtual object or one area of ​​virtual content. In some embodiments, one Fresnel lens may be used to determine the depth of more than one virtual object or more than one area of ​​virtual content.

[0041] Figure 4 is a schematic diagram of a near-eye display 400 having a transmissive image amplitude modulator 402 and a transmissive phase modulator 404 according to some embodiments of the present invention. An optical path 401 through the display 400 is shown. A light source 406 is optically coupled to the transmissive image amplitude modulator 402. The transmissive image amplitude modulator 402 is optically coupled to the transmissive phase modulator 404. The transmissive phase modulator 404 may be optically coupled to a volume holographic diffraction grating eyepiece 410 located in front of a user's eye position 412 via an optical path folding mirror 408 or other suitable light redirector. According to one embodiment, the light source 406, the transmissive image amplitude modulator 402, and the transmissive phase modulator 404 function as a left or right 3D image generator 312, 314. Note that Figure 4 The particular layout shown would be suitable for use as a right image generator. According to alternative embodiments, a second transmissive amplitude modulator that can be used to form one or more zone plate patterns can replace the transmissive phase modulator 404. In some embodiments, additional light redirector components such as collimating mirrors or lenses, prisms, or beam splitters can be added to direct light to the eye location.

[0042] Figure 55 is a schematic diagram of a near-eye display 500 having a reflective amplitude modulator 502 and a reflective phase modulator 504 according to an embodiment of the present invention. An optical path 501 through the display 500 is indicated. A light source 506 is optically coupled to the reflective amplitude modulator 502. Amplitude modulated light reflected by the reflective amplitude modulator 502 is incident on the reflective phase modulator 504. Amplitude and phase modulated light redirected by the reflective phase modulator 504 is directed to a volume holographic diffraction grating eyepiece 510 via an optical path folding mirror 508 or other suitable light redirector, which redirects light received from the optical path folding mirror 508 to an eye position 512 of a user. In some embodiments, additional light redirector components, such as collimating mirrors, lenses, prisms, beam splitters, polarization selective filters, or wave plates, may be arranged along the optical path 501 as the light is directed to the eye position.

[0043] The reflective amplitude modulator 502 may be, for example, an LCoS modulator or a DMD modulator. For example, the reflective phase modulator 504 may be a zero-twist electrically controlled birefringence (ZTECB) LCoS modulator. According to an alternative embodiment, as described above in Figure 2 As discussed in the context of , a second reflective amplitude modulator for forming one or more zone plate patterns may replace the reflective phase modulator 504.

[0044] Figure 6 6 is a schematic diagram of a near-eye display 600 having a transmissive amplitude modulator 602 and a reflective phase modulator 604 according to an embodiment of the present invention. 601 indicates a light path through the display 600. A light source 606 is optically coupled to the transmissive amplitude modulator 602. Light from the light source 606, which is amplitude modulated during transmission through the transmissive amplitude modulator 602, is incident on a cover window 608 covering the reflective phase modulator 604. An outer surface 610 of the cover window 608 may have an anti-reflective coating (on the Figure 6 604). A cover window 608 having a refractive index greater than air may be used to reduce the angle of incidence on the reflective phase modulator 604. Light reflected by the reflective phase modulator 604 through the cover window 608 is incident on the volume holographic diffraction grating eyepiece 612. The holographic diffraction grating eyepiece 612 may be located in front of the eye position 614. The holographic diffraction grating eyepiece 612 may reflect light modulated in amplitude by the transmissive amplitude modulator 602 and in phase by the reflective phase modulator 604 toward the eye position 614. In some embodiments, additional light redirector components (e.g., as previously described with respect to Figure 4-5 Those described above) are added to guide light along the light path or control polarization. For example, the transmission amplitude modulator 602 can be a liquid crystal modulator. The reflective phase modulator can be, for example, a ZTECB LCoS modulator. Note that according to alternative embodiments, as described above in Figure 2As discussed in the context of , a reflective amplitude modulator for forming one or more zone plate patterns may replace the reflective phase modulator 610.

[0045] Figure 7 7 is a schematic diagram of a near-eye display 700 having a reflective amplitude modulator 702 and a transmissive phase modulator 704 according to an embodiment of the present invention. An optical path 701 through the display 700 is indicated. A light source 706 is optically coupled to the reflective amplitude modulator 702. A cover window 712 is disposed on the reflective amplitude modulator 702. By having a refractive index greater than 1, the cover window 712 can be used to reduce the incident angle on the reflective amplitude modulator. An anti-reflective coating (on the outer surface 714 of the cover window 712) can be provided. Figure 7 706 is directed to the volume holographic diffraction grating eyepiece 708 via the transmissive phase modulator 704 and is directed by the holographic diffraction grating eyepiece 708 to the user's eye position 710. In some embodiments, additional light redirector components (e.g., as previously described with respect to Figure 4-6 Those described) may be added to direct light along an optical path or to control polarization.

[0046] Figure 8 8 is a schematic diagram of a near-eye display 800 including a beam splitter 828 between an LCoS amplitude modulator 830 and an LCoS phase modulator 832 according to another embodiment of the present invention. A light engine 834 is used as a red, green, and blue (RGB) light source for the near-eye display 800, although other suitable light engine configurations may be used. Figure 8, in some embodiments, a red laser diode 802 is optically coupled into a red light input face 806 of a red, green, and blue (RGB) dichroic combiner cube 808 through a red laser collimating lens 804. A green laser diode 810 is optically coupled into a green light input face 814 of the RGB dichroic combiner cube 808 through a green laser collimating lens 812. Similarly, a blue laser diode 816 is optically coupled into a blue light input face 820 of the RGB dichroic combiner cube 808 through a blue laser collimating lens 818. The RGB dichroic combiner cube 808 has an output face 822. The RGB dichroic combiner cube 808 includes a red reflecting dichroic mirror (short wavelength pass mirror) 824 set at 45 degrees to reflect light from the red laser diode 802 through the output face 822. The RGB dichroic combiner cube 808 also includes a blue reflecting dichroic mirror (long wavelength pass) 826 set at 135 degrees (perpendicular to the red reflecting dichroic mirror 824) to reflect light from the blue laser diode 816 to the output face 822. The light from the green laser diode 810 passes through (transmits through) the red reflecting dichroic mirror 824 and the blue reflecting dichroic mirror 826 to the output face 822. The red reflecting dichroic mirror 824 and the blue reflecting dichroic mirror 826 can be implemented as thin film optical interference films. Alternatively, the light engine can utilize a photonic chip instead of the RGB combiner cube 808 to combine the light from the laser diodes 802, 810, 816.

[0047] Light exiting the output face 822 of the RGB combiner cube may pass through an optional beam expander 836, which may include a negative lens 838 followed by a positive lens 840, which may be in a Galilean telescope configuration, to output collimated light. Alternatively, only the negative lens 838 is provided. According to another alternative embodiment, a laser beam shaping optic may be provided in place of the beam expander 836. For example, a laser beam shaping optic configured to produce one or more substantially uniform rectangular cross-section beams may be provided.

[0048] Light exiting the beam expander 836, or in the absence of the beam expander 836, light exiting the light engine 834 enters the input face 842 of the beam splitter 844 and propagates to a partial reflector 846 embedded in the beam splitter 844 and oriented at 45 degrees. In some embodiments, the partial reflector 846 is oriented at 45 degrees. For example, the partial reflector 846 can be a neutral density 50% reflector. The light is reflected by the partial reflector 846 to the LCoS amplitude modulator 830. The optical path 850 is Figure 8846. The reflected portion 852 of the optical path 850 extends from the light engine 834 to the LCoS amplitude modulator 830. The reflected portion 852 of the optical path 850 is reflected at the partial reflector 846. The light is selectively reflected by the LCoS amplitude modulator 830, thereby effectively being amplitude modulated. The light reflected by the LCoS amplitude modulator 830 passes through the transmissive portion 854 of the optical path 850 through the partial reflector 846 and reaches the LCoS phase modulator 832, which phase modulates the light in the process of reflecting the light back to the partial reflector 846. The phase modulator 832 can be configured as a reflective analog of a Fresnel lens, a reflective analog of a grid array of Fresnel lenses, or a reflective analog of a non-grid superposition of multiple Fresnel lenses. The phase modulator 832 is used to impart a global wavefront curvature or a spatially varying local wavefront curvature to the image modulated light received from the LCoS amplitude modulator 830. The wavefront curvature or curvature may set one or more effective virtual image distances for an image output by the near eye display 800. Alternatively, the refractive power of the Fresnel lens pattern formed by the phase modulator may be set taking into account the refractive powers of other optical elements along the light path 850 so that the light reaching the user's eye position 866 has a wavefront curvature or curvature corresponding to one or more virtual objects contained in the image output by the near eye display 800. Alternatively, instead of a phase modulator, a second amplitude modulator for generating a zone plate pattern may be provided.

[0049] Light reflected by the LCoS phase modulator 832 is reflected by the partial reflector 846 to an optical path folding mirror 858, which reflects the light through a protective optical window 860 to a volume holographic eyepiece 862. The volume holographic eyepiece 862 includes a grating or other light redirecting feature 864, which is oriented so as to diffract the light toward the user's eye position 866. The near-eye display 800 can be used to Figure 3 The augmented reality glasses 300 shown

[0050] Fig. 9 is a schematic diagram of a near-eye display 900 including a pair of prisms 902, 904 between a digital micromirror device (DMD) light modulator 906 and an LCoS phase modulator 908 according to yet another embodiment of the present invention. Certain elements of the near-eye display 900 indicated by common reference numerals are similar to those of Figure 8800 shown in the drawings, and reference is made to the description above for details thereof. Light exiting the beam expander 836, or, if the beam expander 836 is not used, light exiting the RGB combiner cube 808 (or an alternative light engine, such as a photonic chip-based light engine) enters the input face 910 of the first prism 902 of the prism 902, 904 pair. The light then reaches the second inclined surface 912 of the first prism 902 and is reflected by TIR at the inclined surface 912 to a third surface 914. The light exits the third surface and reaches the DMD light modulator 906. The DMD light modulator 906 includes a two-dimensional micromirror array ( Fig. 9 914). In the "off-state" orientation, the micromirror reflects (after refraction upon re-entering the third surface 914) light at an angle higher than the critical angle of total internal reflection (TIR) ​​at the second inclined surface 912. On the other hand, in the "on-state" orientation, the micromirror reflects (after refraction upon re-entering the third surface 914) light at an angle lower than the critical angle of total internal reflection (TIR) ​​at the second inclined surface 912. In order to achieve the effect of grayscale (e.g., 8-bit, 0-255 light levels) modulation, the percentage of the frame period that each micromirror is in the on-state is controlled. The light reflected by the micromirror in the "on-state" passes through the third surface 914 across the gap 916 to the first inclined surface 918 of the second prism 904 of the pair of prisms 902, 904 and enters the second prism 904. Thereafter, the light reaches and leaves the second surface 920 of the second prism 904 and is incident on the LCoS phase modulator 908. The LCoS phase modulator 908 phase modulates the light and reflects the light back through the second surface 920 of the second prism. Since the light is not incident vertically on the LCoS phase modulator 908, it is also reflected at a certain angle, and the difference between the incident light direction and the reflected light direction makes the light higher than the critical angle when it reaches the first inclined surface 918 of the second prism, and thus reflects to the third exit surface 922 of the second prism 904. As described above with reference to Figure 8 As described above, the light emitted from the third exit surface 922 is propagated to the eye position 866 .

[0051] Fig.10 1 is a schematic representation of a near-eye display 1000 including an OLED source of image intensity modulated light 1002 and a beam splitter 828 between a spatial phase modulator 1004 according to another embodiment of the present invention. The image intensity modulated OLED light source 1002, which may take the form of an OLED microdisplay, is an emissive display, and thus Figure 8 and Fig. 9 The components shown (e.g., laser diode, collimating lens, RGB combiner cube) are Fig.10is not used in the illustrated near-eye display 1000. A portion of the image intensity modulated OLED light source 1002 is coupled to the spatial phase modulator 1004 via a beam splitter 828. The spatial phase modulator 1004 may take the form of an LCoS phase modulator. In some embodiments, the beam splitter may take the form of a neutral density beam splitter that reflects a specific portion (e.g., nominally 1 / 2) of the incident light and transmits a specific portion of the incident light. A portion of the light reflected and phase modulated by the spatial phase modulator is reflected at the anti-partial reflector 846 embedded in the beam splitter 828 toward the folding mirror 858, thereby being transmitted through the above reference Figure 8 The more fully described light path propagates to the user's eye position 866. In some embodiments, other suitable light redirection components (e.g., those previously described with reference to Figure 4-7 Those described) may be used in addition to or in place of fold mirror 858.

[0052] Fig.11 1 is a block diagram of a near-eye display system 1100 according to some embodiments of the present invention. The system 1100 includes a processor 1102 coupled to a left eye tracking camera 324, a right eye tracking camera 326, a graphics processing unit (GPU) 1104, and a memory 1106. For example, the memory 1106 may include transistor circuits such that the combination of the processor 1102, the GPU 1104, and the memory 1106 forms a larger electronic circuit. The memory 1106 may include a game engine 1108 executed by the processor 1102 and the GPU 1104. The game engine 1108 maintains (e.g., stores and updates) 3D scene data 1110 and implements a right eye virtual camera 1112 and a left eye virtual camera 1114, which differ from each other by a coordinate offset in a 3D virtual environment defining the 3D scene data 1110. The coordinate offset corresponds to the spacing of human eyes and is optionally set for each user. For each virtual camera 1112, 1114, a frustum fixed to the head orientation direction is defined and used to select a portion of the 3D scene data for rendering. The GPU 1104 includes a Z buffer 1116, a right frame buffer 1118, and a left frame buffer 1120. The right eye virtual camera 1112 is coupled to the right eye frame buffer 1118 and transmits the right eye scene data to the right eye frame buffer 1118. Similarly, the left eye virtual camera 1114 is coupled to the left eye frame buffer 1120 and provides the left eye scene data to the left eye frame buffer 1120. The game engine 1108 also provides depth coordinate information for points in the 3D scene data 1110 to the Z buffer 1116 of the GPU 1104.

[0053] The processor 1102 is further coupled to a left spatial phase / zone plate modulator driver 1122 and a right spatial phase / zone plate modulator driver 1124. The GPU 1104 is coupled to a left spatial amplitude modulator driver 1126 and a right spatial amplitude modulator driver 1128 so that the right eye image and the left eye image can be output from the right frame buffer 1118 and the left frame buffer 1120 to the left spatial amplitude modulator 1126 and the right spatial amplitude modulator driver 1128, respectively. The left spatial phase / zone plate modulator 1122 is coupled to the left spatial phase or zone plate modulator 108L, 208L, and the right spatial phase / zone plate modulator 1124 is coupled to the right spatial phase or zone plate modulator 108R, 208R, so that each modulator driver drives (e.g., controls) a respective zone plate modulator.

[0054] According to one mode of operation, the processor 1102 receives information from the eye tracking cameras 324, 326 indicating the direction in which the user is looking. The processor 1102 accesses information from the Z buffer 1116 indicating the depth of the virtual content corresponding to or closest to the direction in which the user is looking. The processor 1102 then sends a Fresnel lens pattern or a zone plate pattern to the spatial phase / zone plate modulator driver 1122, 1124, the Fresnel lens pattern or the zone plate pattern having a depth based on the virtual content corresponding to or closest to the direction in which the user is looking. Taking into account the refractive power of any other optical elements (e.g., eyepieces 308, 310) in the path between the spatial amplitude modulator 106L, 206L, 108R, 208R and the user's eye position, the focal length of the Fresnel lens or zone plate pattern sent to the driver 1124, 1124 is set so that the wavefront curvature of the light reaching the user's eye will be the inverse of the value from the Z buffer associated with (corresponding to or closest to) the direction in which the user is looking. Additionally, in some embodiments, the Fresnel lens or zone plate pattern sent to the spatial phase / zone plate modulator driver is moved (eg, Fig.13 ), to direct light toward the user's pupil based on information about the user's instantaneous pupil position obtained from eye tracking cameras 324, 326.

[0055] According to an alternative embodiment, the processor 1102 accesses information indicating the depth of the plurality of virtual objects from the Z-buffer. The processor 1102 then generates a grid of Fresnel lens patterns or zone plate patterns, wherein each of the plurality of Fresnel lens patterns or zone plate patterns has a focal length selected to set the curvature of light reaching the user's eye position to a value matching the distance of the corresponding virtual object based on the information accessed from the Z-buffer. According to a variation of the previous embodiment, the plurality of Fresnel lens patterns or zone plate patterns are arranged in a non-grid arrangement.

[0056] The optical coupling described above may include coupling by free space propagation of light between relatively positioned optical components that are relatively positioned so that light propagated from one component is received by the second component. In this application, image intensity modulated light, image modulated light, amplitude modulated light, image amplitude modulated light, and image modulated light may be used interchangeably to indicate image data encoded in light that varies in amplitude (i.e., intensity of a given wavelength) as the image changes over time.

Claims

1. A near-eye display system, comprising: Image amplitude modulated light source; an active area plate modulator arranged to receive light from said image amplitude modulated light source; as well as An eye-coupling optic is arranged to receive light from the active area plate modulator.

2. The near-eye display system of claim 1, wherein the active area panel modulator comprises a liquid crystal on silicon light modulator.

3. The near-eye display system of claim 1, wherein the active area plate modulator comprises a digital micromirror device light modulator.

4. The near-eye display system of claim 1 , wherein the eye-coupling optical component comprises a volume holographic diffraction grating.

5. The near-eye display system according to claim 1, further comprising: Eye tracking camera; circuitry coupled to the image amplitude modulated light source, the active area plate modulator, and the eye tracking camera, wherein the circuitry is configured to: driving the image amplitude modulation light source to display a scene including a plurality of virtual objects; receiving information from the eye tracking camera indicating a particular virtual object among the plurality of virtual objects that a user is viewing; as well as The active area plate modulator is driven to adjust a light wavefront curvature based on a distance associated with the particular virtual object of the plurality of virtual objects identified based on the information from the eye tracking camera.

6. The near-eye display system of claim 5, wherein the circuit is further configured to drive the active area plate modulator to produce an area plate pattern that moves based on the information from the eye tracking camera.

7. The near-eye display system of claim 1, wherein the active area plate modulator comprises a reflective light modulator.

8. The near-eye display system of claim 1, wherein the active area plate modulator comprises a transmissive light modulator.

9. The near-eye display system of claim 1, wherein the near-eye display system is a pair of augmented reality glasses.

10. The near-eye display system of claim 1, wherein the light source comprises a laser diode.

11. The near-eye display system of claim 1 , wherein the eye-coupling optical component comprises a diffraction grating.

12. The near-eye display system of claim 1, wherein the active zone plate is configured to form a zone plate of varying focal length by presenting a zone plate pattern comprising alternating light and dark rings.

13. The near-eye display system of claim 1, wherein the active area plate modulator is coupled to the eye coupling optics.

14. A near-eye display system, comprising: Image amplitude modulated light source; a spatial phase modulator optically coupled to the image amplitude modulated light source, wherein the spatial phase modulator is configured to impart a wavefront curvature to light received from the image amplitude modulated light source; as well as Eye coupling optics are optically coupled to the spatial phase modulator.

15. The near-eye display system of claim 14, wherein: The image amplitude modulated light source comprises a pixelated emitting light source for generating an image; and The spatial phase modulator is positioned along the optical path between the pixelated emission light source and the eye coupling optics.

16. The near-eye display system of claim 15, wherein the pixelated emissive light source comprises an organic light emitting diode panel.

17. The near-eye display system of claim 16, wherein the pixelated emissive light source comprises a micro-light emitting diode panel.

18. The near-eye display system according to claim 14, comprising: A phase modulator driver is coupled to the spatial phase modulator, wherein the phase modulator driver is configured to generate a diffractive lens pattern on the spatial phase modulator.

19. The near-eye display system of claim 18, wherein the phase modulator driver is configured to receive depth information and generate a diffractive lens pattern based on the depth information.

20. The near-eye display system of claim 18, the phase modulator driver being configured to generate a diffractive lens pattern array and the diffractive lens pattern being included in the diffractive lens pattern array.

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