Near-eye 3D display with separate phase and amplitude modulators

Abstract

An augmented reality eyeglass includes a near-eye display that includes an image amplitude modulated light source coupled with a spatial phase modulator or active area panel modulator and optically coupled with an eye coupling optic. The image amplitude modulated light source can include a light emitting 2D display panel or a light source coupled to an image amplitude modulator. The eye coupling optic can include a volume holographic diffraction grating.

Description

[0001] This application is a divisional application of the patent application with international application number PCT / US2018 / 052882, international application date of September 26, 2018, Chinese national application number 201880062496.1, entitled "Near-eye 3D Display with Separate Phase and Amplitude Modulators". Technical Field

[0002] This invention relates to near-eye displays. More specifically, this invention relates to near-eye three-dimensional (3D) displays. Background Technology

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

[0004] It is now anticipated that smartphones will eventually be replaced or become essential augmented by augmented reality glasses, which, among other things, will effectively provide users with a relatively large field-of-view 3D image output system that is readily accessible to both business and entertainment purposes.

[0005] Not only do they exceed the screen size of laptops and eliminate the inconvenience of carrying laptops, augmented reality glasses will also provide new hybrid reality applications that seamlessly integrate real-world and virtual content. This not only maintains the user's connection to the real world, thus preventing the social phenomenon of withdrawal from real-world interaction sometimes associated with excessive smartphone use, but also enables new extensions of the physical world, such as: automatically generating context-sensitive information overlaid on automatically recognized real-world objects; communication between remote individuals through 3D avatars of each party displayed to the other; and hybrid reality games that include realistically rendered virtual content, such as respecting the boundaries of physical objects in the real world. Summary of the Invention

[0006] One aspect of augmented reality glasses is displaying virtual content through transparent eyepieces. One type of transparent eyepiece is based on a waveguide that includes transparent diffractive optical elements for controlling the propagation of light carrying the 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 leads to higher power consumption, and consequently, shorter battery life and associated thermal management requirements.

[0007] Furthermore, to enhance the realism of virtual content, it is desirable to display the content at different depths. Appropriately displaying content at a certain distance from the user requires bending the wavefront of the light used to generate the virtual image of the content. Curvature is inversely related to the virtual image distance. To achieve multiple virtual image distances when using waveguide-based eyepieces, a stack of waveguides is used, each with different coupling optics. This latter approach effectively limits the available virtual distances to a small, finite number, for example, two selectable distances.

[0008] The embodiments described herein improve the efficiency of coupling 3D images through optical component queues and to the user's eye, and are more comprehensive in terms of the ability to control the depth of virtual images.

[0009] Embodiments of the present invention provide augmented reality glasses including a near-eye display comprising an image intensity modulation light source coupled to a spatial phase modulator, the spatial phase modulator being capable of applying spatially varying phase modulation across a beam received by the image intensity modulation light source. The spatial phase modulator is also coupled to an eye-coupling optics. The image intensity modulation light source may take the form of, for example, 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 may also take the form of an LCoS modulator. The eye-coupling optics may take the form of an off-axis holographic diffraction grating that receives light at a relatively high angle of incidence compared to the angle at which light is redirected to the user's eye, thereby allowing a portion of the near-eye display to be positioned to one side of the user's eye. In some embodiments, the optical path between the light source and the eye-coupling optics may reach the amplitude modulator before reaching the spatial phase modulator. The near-eye display may further include a beam splitter disposed between the amplitude modulator and the spatial phase modulator. Attached Figure Description

[0010] The accompanying drawings illustrate the design and utility of preferred embodiments of the invention, wherein similar elements are referenced by public reference numerals. To better understand how the above and other advantages and objects of the invention are obtained, a more specific description of the invention will be presented with reference to specific embodiments of the invention shown in the accompanying drawings.

[0011] It is understood that these accompanying drawings depict only typical embodiments of the invention and should not be construed as limiting its scope. The invention will be described and explained with additional specificity and detail using the accompanying drawings, wherein:

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

[0013] Figure 2This is 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 is shown according to some embodiments of the present invention;

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

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

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

[0019] Figure 8 This 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] Figure 9 This is a schematic diagram of a near-eye display including a prism pair between a DMD optical modulator and an LCoS phase modulator, according to some embodiments of the present invention.

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

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

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

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

[0025] Figure 14 According to some embodiments of the present invention Figure 2The illustration shows a depiction of a slab lens formed on an active slab modulator included in the display.

[0026] Figure 15 According to some embodiments of the present invention, it is possible to Figure 2 The illustration shows a grid of slab patterns formed on an active slab modulator included in the display; and

[0027] Figure 16 These are schematic diagrams illustrating the operation of some embodiments of the present invention. Detailed Implementation

[0028] Figure 1 This is a block diagram of a near-eye display 100 according to some embodiments of the present invention. See the reference figure. Figure 1 As shown, the near-eye display 100 includes an image amplitude modulation light source 102. As illustrated, the image amplitude modulation 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, for example, include an LCoS modulator, a DMD modulator, or a transmissive liquid crystal modulator. Figure 2 The alternatives shown are as follows: Figure 1 As shown, the image amplitude modulation light source can take the form of a pixelated light-emitting display panel, such as an OLED display panel or a micro LED display panel.

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

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

[0031] Figure 2 This 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 modulation 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 an LD. Any other suitable light source may be used.

[0032] Image amplitude modulation light source 202 is optically coupled to active plate modulator 208. Active plate modulator 208 can reconfigurably form plates with varying focal lengths by presenting a plate pattern including alternating bright and dark rings. Active plate modulator 208 can be a reflected light modulator or a transmitted light modulator. The active plate modulator can be implemented using, for example, a DMD modulator, an LCoS modulator, or a transmissive liquid crystal (LC) modulator. Active plate modulator 208 can be used to present a single plate pattern, a grid of multiple plate patterns, or a non-grid superposition of plate patterns. A single plate pattern can be used to impart a wavefront curvature to the image modulated light received from image amplitude modulation light source 202. On the other hand, multiple plate patterns can be used to impart different wavefront curvatures to different portions of the image modulated light received from image amplitude modulation light source 202. In each case, the wavefront curvature corresponds to the inverted virtual image distance image presented by near-eye display 200. Depth perception of the image presented by the near-eye display system is enhanced by bending the wavefront of the light used to present the image based on a predetermined distance to virtual content (e.g., living and inanimate objects) in the presented image. In the case of implementing multiple slab patterns, a first portion of the image-modulated light carrying an image of a first virtual object (e.g., a book) can be diverged by a first slab pattern to have a first curvature corresponding to the reciprocal of a first desired distance to the first virtual object, and a second portion of the image-modulated light carrying a second virtual object (e.g., an avatar) can be diverged by a second slab pattern to have a second curvature corresponding to the reciprocal of a second desired distance to the second virtual object. An active slab modulator 208 is coupled to an eye-coupled optics 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 user's left eye position 320 and right eye position 322 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 and 314 may each include an image amplitude modulation light source 102 combined with the spatial phase modulator 108, or may include an image amplitude modulation light source 202 combined with the active plate modulator 208. The left and right volume holographic diffraction grating eyepieces 308 and 310 are possible embodiments of the eye-coupled optics 110 and 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 left and right image generators 312, 314 may include one or more virtual objects at different depths. Eye-tracking cameras 324, 326 may be used to determine which specific virtual object the user is viewing. Based on the desired depth of the specific virtual object the user is viewing, a spatial phase modulator 108 or an active plate modulator 208 may be used to form a negative power lens that imparts a diverging (convex towards 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 specific virtual object the user is viewing (as determined by eye-tracking cameras 324, 326). The depth of each specific virtual object may be determined by one or more programs, such as an augmented reality program that generates the virtual object. Furthermore, the negative lens pattern formed by the spatial phase modulator 108 or the active plate modulator 208 may be laterally moved to deflect the light so that, after being redirected by eyepieces 308, 310, the light will be incident on the user's pupil.

[0035] refer to Figure 12This illustrates a diffractive Fresnel lens pattern 1200 that can 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 can be generated in response to the detection by an eye-tracking camera 324326 that a user is viewing virtual content at a depth (distance from the user) equal to the focal length. The focal length can be changed as needed depending on the distance between the user and the virtual content being viewed. The focal length of the diffractive Fresnel lens pattern can be adjusted as the user changes the direction of their gaze, such that the resulting wavefront curvature corresponds to the distance associated with the virtual content currently being viewed by the user.

[0036] refer to Figure 13 A second Fresnel lens pattern 1300 is shown. The second lens pattern 1300 is laterally moved relative to the centered first Fresnel lens pattern. The second Fresnel lens pattern is laterally moved based on the movement of the user's eye position determined by the eye-tracking cameras 324, 326, in order to deflect light along the light path (including redirection by eyepieces 308, 310) to suit the user's viewing. The Fresnel lens pattern 1300 can move in any direction to track the user's gaze and couple into the user's eye through the pupil. In some embodiments, the positional 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 Figure 14 The diagram illustrates a negative plate pattern 1400. The negative plate pattern 1400 can be formed on the active plate modulator 208 and can be used in place of the negative diffraction Fresnel pattern 1200 to give the wavefront of light received from the image amplitude modulation light source 202 a radius of curvature based on (e.g., equal to) the distance to the virtual object being viewed by the user, determined by the eye-tracking cameras 324, 326. The negative plate pattern 1400 can also be laterally shifted based on information obtained from the eye-tracking cameras 324, 326 regarding the position of the user's pupil to deflect light towards the user's pupil.

[0038] Those skilled in the art will understand that while this disclosure relates to tracking a user's pupil in a particular embodiment, other eye anatomy can be used for imaging or positioning. For example, retinal images can be acquired and aggregated over time to provide a retinal map, wherein any single retinal image acquired by the eye-tracking cameras 324, 326 at a given time corresponds to the eye's gaze direction. That is, when the pupil changes gaze direction, it provides an aperture of variable position 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 Figure 15The diagram illustrates a grid of four panel patterns 1500, including an upper left panel pattern 1502, an upper right panel pattern 1504, a lower left panel pattern 1506, and a lower right panel pattern 1508. In this example configuration, the upper left panel pattern 1502 and the lower left panel pattern 1506 are identical, while the upper right panel pattern 1504 and the lower right panel pattern 1508 are different. Each of the four panel patterns 1502, 1504, 1506, and 1508 has a negative focal length related to (e.g., equal to) the distance to a particular virtual object or part of a virtual scene, which is presented as intensity / amplitude modulated light incident on the particular panel pattern (e.g., 1502, 1504, 1506, 1508) emitted from image modulation light sources 102 and 202. Therefore, for example, an image of a virtual bee can be coupled through one of the panel patterns 1502, 1504, 1506, and 1508 in the grid 1500, and an image of a virtual butterfly can be coupled through another of the panel patterns 1502, 1504, 1506, and 1508 in the grid 1500. Although in Figure 15 Not shown, but as with the Fresnel lens 1300, each of the slab patterns 1502, 1504, 1506, and 1508 can be moved based on the movement of the user's pupil in order to guide light into the user's pupil and ensure that the corresponding virtual object and slab pattern are aligned.

[0040] Figure 16This is a schematic diagram illustrating the operation of certain embodiments of the present invention. An optical amplitude modulator 1602 modulates light to represent three virtual objects. A first portion 1604 of the amplitude modulated light is used to represent a first virtual object, a second portion 1606 is used to represent a second virtual object, and a third portion 1608 is used to represent a third virtual object. Each of the three portions 1604, 1606, and 1608 of the amplitude modulated light has a finite divergence angle. The finite divergence angle can be attributed to the high degree of collimation of the light illuminating the optical amplitude modulator (e.g., a laser) and the limited extent to which the optical amplitude modulator 1602 increases the light divergence. The optical amplitude modulator 1602 may include pixels that generate an outgoing light cone, the divergence of which may have upper and / or lower limits imposed by the inclusion of incident, diffracting, and / or reflecting or transmitting diffuse optical materials. First, second, and third portions 1604, 1606, and 1608 of amplitude-modulated light are incident on first, second, and third Fresnel lens patterns 1610, 1612, and 1614, respectively, which can be dynamically formed on phase modulator 1616. Each of the dynamically formed Fresnel lens patterns 1610, 1612, and 1614 has a selected focal length to impart a specific optical field curvature to the first, second, and third portions 1604, 1606, and 1608 of the amplitude-modulated light. Depending on the divergence of the portions 1604, 1606, and 1608 of the amplitude-modulated light arriving at phase modulator 1616, the dynamically formed Fresnel lens patterns 1610, 1612, and 1614 can have positive or negative focal lengths. However, typically, after interacting with phase modulator 1616, the light will diverge (rather than converge) with a radius of curvature related to the distance to the virtual object. Note that in some embodiments, 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 eyepieces 308, 310 and the optical refractive power of the dynamically formed Fresnel lens patterns 1610, 1612, 1614. In the latter case, light leaving phase modulator 1616 may converge. Figure 16 As shown on the right, the first portion 1618 of the wavefront curvature control light is formed by the first portion 1604 of the amplitude modulation light through the action of a first dynamically formed Fresnel lens pattern 1610. Similarly, the second portion 1620 of the wavefront curvature control light is formed by the second portion 1606 of the amplitude modulation light through the action of a second dynamically formed Fresnel lens 1612. The third portion 1622 of the wavefront curvature control light is formed by the third portion 1608 of the amplitude modulation light through the action of a third dynamically formed Fresnel lens 1614. Figure 3In the illustrated embodiment, the three portions 1618, 1620, and 1622 of the wavefront curvature control light are optically coupled to the user's eye positions 320 and 322 via a volume holographic diffraction grating eyepiece. Alternatively, other types of eyepieces can be used to couple the three portions 1618, 1620, and 1622 of the wavefront curvature control light to the user's eye position. Although Figure 16 Three virtual objects are shown displayed at three virtual depths, but other embodiments are possible. For example, one or more portions of amplitude-modulated light formed by the action of one or more dynamically formed Fresnel lenses can be used to display one or more virtual objects at one or more depths. In some embodiments, a Fresnel lens can be used to determine the depth of a region of a virtual object or virtual content. In some embodiments, a Fresnel lens can be used to determine the depth of more than one region of more than one virtual object or virtual content.

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

[0042] Figure 5This 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. The light 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. The amplitude- and phase-modulated light redirected by the reflective phase modulator 504 is directed via an optical path folding mirror 508 or other suitable light redirector to a volume holographic diffraction grating eyepiece 510, which redirects the light received from the optical path folding mirror 508 to the user's eye position 512. In some embodiments, when light is directed to the eye position, additional light redirector components, such as collimating mirrors, lenses, prisms, beam splitters, polarization-selective filters, or waveplates, may be arranged along the light path 501.

[0043] The reflection amplitude modulator 502 may be, for example, an LCoS modulator or a DMD modulator. For example, the reflection phase modulator 504 may be a zero-twist electrically controlled birefringence (ZTECB) LCoS modulator. According to alternative embodiments, as described above... Figure 2 In the context discussed, the second reflection amplitude modulator used to form one or more plate patterns can replace the reflection phase modulator 504.

[0044] Figure 6 This is a schematic diagram of a near-eye display 600 having a transmission amplitude modulator 602 and a reflection phase modulator 604 according to an embodiment of the present invention. The light path 601 through the display 600 is indicated. A light source 606 is optically coupled to the transmission amplitude modulator 602. Light from the light source 606 is amplitude modulated during transmission through the transmission amplitude modulator 602 and incident on a cover window 608 covering the reflection phase modulator 604. The outer surface 610 of the cover window 608 may have an anti-reflection coating (on...). Figure 6 (Not visible in the image). A cover window 608 having a refractive index greater than that of air can 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 by the transmission amplitude modulator 602 and modulated by the reflective phase modulator 604 toward the eye position 614. In some embodiments, an additional light redirector component (e.g., previously mentioned) Figure 4-5 Those described are added to guide light along the optical path or control polarization. For example, the transmission amplitude modulator 602 may be a liquid crystal modulator. The reflection phase modulator may be, for example, a ZTECB LCoS modulator. Note that, according to alternative embodiments, as described above... Figure 2As discussed in the context, the reflection amplitude modulator used to form one or more plate patterns can replace the reflection phase modulator 610.

[0045] Figure 7 This is a schematic diagram of a near-eye display 700 having a reflection amplitude modulator 702 and a transmission phase modulator 704 according to an embodiment of the present invention. The light path 701 through the display 700 is indicated. A light source 706 is optically coupled to the reflection amplitude modulator 702. A cover window 712 is provided on the reflection amplitude modulator 702. By having a refractive index greater than 1, the cover window 712 can be used to reduce the angle of incidence on the reflection amplitude modulator. An anti-reflection coating (on the outer surface 714 of the cover window 712) can be provided. Figure 7 (Not visible in the image). Light from the light source 706, modulated and reflected by the reflection amplitude modulator 702, is directed by the transmission phase modulator 704 to the volume holographic diffraction grating eyepiece 708, and then directed by the holographic diffraction grating eyepiece 708 to the user's eye position 710. In some embodiments, an additional light redirector component (e.g., previously mentioned) Figure 4-6 Those described can be added to guide light along the optical path or control polarization.

[0046] Figure 8 This 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. The light engine 834 serves as the red-green-blue (RGB) light source for the near-eye display 800, although other suitable light engine configurations may be used. Reference Figure 8In some embodiments, a red laser diode 802 is optically coupled to the red light input surface 806 of an RGB (red, green, blue) dichroic combiner cube 808 via a red laser collimating lens 804. A green laser diode 810 is optically coupled to the green light input surface 814 of the RGB dichroic combiner cube 808 via a green laser collimating lens 812. Similarly, a blue laser diode 816 is optically coupled to the blue light input surface 820 of the RGB dichroic combiner cube 808 via a blue laser collimating lens 818. The RGB dichroic combiner cube 808 has an output surface 822. The RGB dichroic combiner cube 808 includes a red reflective dichroic mirror (short wavelength through the mirror) 824 set at a 45-degree angle to reflect light from the red laser diode 802 through the output surface 822. The RGB dichroic combiner cube 808 also includes a blue dichroic reflector (long wavelength pass-through) 826 set at 135 degrees (perpendicular to the red dichroic reflector 824) to reflect light from the blue laser diode 816 to the output surface 822. Light from the green laser diode 810 is transmitted (transmitted through) to the output surface 822 via the red dichroic reflector 824 and the blue dichroic reflector 826. The red dichroic reflector 824 and the blue dichroic reflector 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 light from the laser diodes 802, 810, and 816.

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

[0048] Light exiting beam expander 836, or, in the absence of beam expander 836, light exiting optical engine 834, enters the input surface 842 of beam splitter 844 and propagates to a partial reflector 846 embedded within beam splitter 844 and oriented at 45 degrees. In some embodiments, the partial reflector 846 is oriented at 45 degrees. For example, partial reflector 846 may be a neutral density 50% reflector. Light is reflected by partial reflector 846 to LCoS amplitude modulator 830. Optical path 850 is... Figure 8As shown in the diagram, the reflective portion 852 of the optical path 850 extends from the optical engine 834 to the LCoS amplitude modulator 830. The reflective portion 852 of the optical path 850 reflects light at a partial reflector 846. 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 partial reflector 846 and reaches the transmission portion 854 of the optical path 850 to the LCoS phase modulator 832, which modulates the phase of the light as it is reflected back to the partial reflector 846. The phase modulator 832 can be configured as a reflective analogue of a Fresnel lens, a reflective analogue of a lattice array of Fresnel lenses, or a reflective analogue of a non-lattice superposition of multiple Fresnel lenses. The phase modulator 832 is used to impart global wavefront curvature or spatially varied local wavefront curvature to the image-modulated light received from the LCoS amplitude modulator 830. The wavefront curvature or curvature can set one or more effective virtual image distances for the image output by the near-eye display 800. Alternatively, the refractive power of the Fresnel lens pattern formed by the phase modulator can be set taking into account the refractive power of other optical elements along the light path 850, such 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 the phase modulator, a second amplitude modulator can be provided for generating the slab pattern.

[0049] Light reflected by the LCoS phase modulator 832 is reflected by a 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 redirection feature 864, which is oriented to diffract light toward the user's eye position 866. A near-eye display 800 can be used... Figure 3 Among the 300 augmented reality glasses shown

[0050] Figure 9 This is a schematic diagram of a near-eye display 900 including a pair of prisms 902, 904 between a digital micromirror device (DMD) optical modulator 906 and an LCoS phase modulator 908, according to another embodiment of the present invention. Certain elements of the near-eye display 900, indicated by common reference numerals, are... Figure 8The near-eye display 800 shown is shared, and its details are described above. Light exiting the beam expander 836, or, without the beam expander 836, the RGB combiner cube 808 (or an alternative light engine, such as a photonic chip-based light engine), enters the input surface 910 of the first prism 902 of the prism pair 902, 904. The light then reaches the second tilted surface 912 of the first prism 902 and is reflected by TIR at the tilted surface 912 to the 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 (DMI) that can be oriented to one of two orientations under the control of the input video signal. Figure 9 (Not shown in the image). In the "off-state" orientation, the micromirrors reflect light (after refraction upon re-entry into the third surface 914) at an angle higher than the critical angle of total internal reflection (TIR) ​​at the second tilted surface 912. On the other hand, in the "on-state" orientation, the micromirrors reflect light (after refraction upon re-entry into the third surface 914) at an angle lower than the critical angle of total internal reflection (TIR) ​​at the second tilted surface 912. To achieve the effect of grayscale (e.g., 8-bit, 0-255 optical level) modulation, the percentage of the frame period during which each micromirror is in the on-state is controlled. In the "on-state," the light reflected by the micromirrors crosses the gap 916 through the third surface 914 to the first tilted 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 exits 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 it back through the second surface 920 of the second prism. Since the light is not incident perpendicularly on the LCoS phase modulator 908, it is also reflected at an angle, and the difference between the incident and reflected light directions causes the light to be above a critical angle when it reaches the first tilted surface 918 of the second prism, thus reflecting to the third exit surface 922 of the second prism 904. (Refer to the above text.) Figure 8 The light emitted from the third emitting surface 922 is propagated to the eye position 866.

[0051] Figure 10 This is a schematic representation of a near-eye display 1000 comprising a beam splitter 828 between an OLED source 1002 with image intensity modulated light and a spatial phase modulator 1004, according to another embodiment of the present invention. The image intensity modulated OLED light source 1002, which may be in the form of an OLED microdisplay, is an emitting display, therefore... Figure 8 and Figure 9 The components shown (e.g., laser diode, collimating lens, RGB combiner cube) are in Figure 10This is not used in the near-eye display 1000 shown. 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 be in the form of an LCoS phase modulator. In some embodiments, the beam splitter may be in 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 toward the folded mirror 858 at the anti-reflector 846 embedded in the beam splitter 828, thus through the above reference. Figure 8 A more comprehensive description of the light path propagating to the user's eye position 866. In some embodiments, other suitable light redirection components (e.g., previously mentioned) Figure 4-7 Those described may be used additionally or in place of the folding reflector 858, in addition to the folding reflector 858.

[0052] Figure 11 This is a block diagram of a near-eye display system 1100 according to some embodiments of the present invention. System 1100 includes a processor 1102, a graphics processing unit (GPU) 1104, and a memory 1106 coupled to a left-eye tracking camera 324 and a right-eye tracking camera 326. For example, memory 1106 may include transistor circuitry such that the combination of processor 1102, GPU 1104, and memory 1106 forms a larger electronic circuit. Memory 1106 may include a game engine 1108 executed by processor 1102 and GPU 1104. 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 are differentiated from each other by coordinate offsets in a 3D virtual environment defining the 3D scene data 1110. The coordinate offsets correspond to the distance between human eyes and are 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. 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 right-eye scene data to it. Similarly, the left-eye virtual camera 1114 is coupled to the left-eye frame buffer 1120 and provides left-eye scene data to it. Game engine 1108 also provides depth coordinate information for points in the 3D scene data 1110 to the Z-buffer 1116 of GPU 1104.

[0053] The processor 1102 is further coupled to a left spatial phase / slab modulator driver 1122 and a right spatial phase / slab modulator driver 1124. The GPU 1104 is coupled to a left spatial amplitude modulator driver 1126 and a right spatial amplitude modulator driver 1128, such 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 / slab modulator 1122 is coupled to left spatial phase or slab modulators 108L, 208L, and the right spatial phase / slab modulator 1124 is coupled to right spatial phase or slab modulators 108R, 208R, such that each modulator driver drives (e.g., controls) its respective slab modulator.

[0054] According to one operating mode, processor 1102 receives information from eye-tracking cameras 324, 326 indicating the direction a user is looking. Processor 1102 accesses information from Z-buffer 1116 indicating the depth of the virtual content corresponding to or closest to the direction the user is looking at. Processor 1102 then sends a Fresnel lens pattern or slab pattern to spatial phase / slab modulator drivers 1122, 1124, the Fresnel lens pattern or slab pattern having a depth based on the virtual content corresponding to or closest to the direction the user is looking at. Taking into account the refractive power of any other optical elements (e.g., eyepieces 308, 310) in the path between spatial amplitude modulators 106L, 206L, 108R, 208R and the user's eye position, the focal length of the Fresnel lens or slab pattern sent to drivers 1124, 1124 is set such that the wavefront curvature of the light reaching the user's eye will be the reciprocal of the value from the Z-buffer associated with (corresponding to or closest to) the direction the user is observing. Furthermore, in some embodiments, the Fresnel lens or slab pattern sent to the spatial phase / slab modulator driver is shifted (e.g., Figure 13 As shown), light is directed toward the user's pupil based on information about the user's instantaneous pupil position obtained from eye-tracking cameras 324 and 326.

[0055] According to an alternative embodiment, processor 1102 accesses information indicating the depth of a plurality of virtual objects from a Z-buffer. Processor 1102 then generates a grid of Fresnel lens patterns or slab patterns, each of the plurality of Fresnel lens patterns or slab patterns having a focal length selected such that the curvature of light reaching the user's eye position is set to a value matching the distance to 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 slab patterns are arranged in a non-grid configuration.

[0056] The optical coupling described above may include free-space propagation coupling between optical components that are relatively positioned such that light propagating 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 are used interchangeably to indicate image data encoded in light whose amplitude (i.e., intensity at a given wavelength) changes with the image over time.

Claims

1. A near-eye display system, comprising: Image amplitude modulation light source; An active slab modulator is arranged to receive light from the image amplitude modulation light source and is configured to generate two or more slab patterns. as well as An eye-coupled optical component is arranged to receive light from the active plate modulator. Wherein, the first plate pattern of the two or more plate patterns determines the first depth of the first object in the image formed by the light, and the second plate pattern of the two or more plate patterns determines the second depth of the second object in the image formed by the light.

2. The near-eye display system according to claim 1, wherein the active plate modulator comprises a liquid crystal on silicon light modulator.

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

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

6. The near-eye display system of claim 5, wherein the circuitry is further configured to drive the active slab modulator to generate a slab pattern based on the movement of the information from the eye-tracking camera.

7. The near-eye display system according to claim 1, wherein the active plate modulator includes a reflected light modulator.

8. The near-eye display system according to claim 1, wherein the active plate modulator comprises a transmitted light modulator.

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

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

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

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

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

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