Multi-depth plane three-dimensional display using a waveguide reflector array projector

Abstract

A two-dimensional array of linear waveguides includes a plurality of 2D planar waveguides assembled, columns, sets, or layers, each of which generates a corresponding depth plane for a simulated 4D light field. The linear waveguides can have a rectangular cylindrical shape and can be stacked in rows and columns. Each linear waveguide is at least partially internally reflective, e.g., by at least one opposing pair of at least partially reflective planar sidewalls, to propagate light along the length of the waveguide. The curved microreflectors can reflect some modes of light while allowing others to pass through. The sidewalls or faces can reflect some modes of light while allowing others to pass through. The curved microreflectors of any given waveguide contribute to a spherical wavefront at a defined radial distance, and each layer generates an image plane at a corresponding radial distance.

Description

[0001] This application is a divisional application of the patent application with the application date of June 11, 2013, application number 201711239821.0, and title "Multi-depth plane three-dimensional display using a waveguide reflector array projector". Background Art

[0002] A light field includes all the light rays at each point in space traveling in corresponding directions. The light field is considered four-dimensional because each point in three-dimensional space also has an associated direction, which is the fourth dimension.

[0003] Wearable three-dimensional displays include substrate-guided optical devices, also known as light-guide optical element (LOE) systems. Such devices are manufactured, for example, by Lumus Ltd. As Figure 1B-1 、 1B-2 shown in FIGS. 1B-1 and 1B-3, the LOE system 10 uses a single-layer waveguide 12 composed of two parallel planar surfaces 14a, 14b. Light 16 is coupled into the LOE waveguide 12 using a micro-projector (not shown) and a reflector strip 18. Figure 1B-1 、 1B-2 FIGS. 1B-1, 1B-2, and 1B-3 show the waveguide 12 of the LOE system 10, showing light 16 entering at three corresponding angles. The LOE system 10 uses planar micro-reflectors 20a-20n (only two are shown for clarity of drawing), which are oriented only along one angular direction and are positioned parallel to each other. However, the LOE system 10 projects only to a single depth plane focused at infinity, with a spherical wavefront curvature of zero. Brief Description of the Drawings

[0004] In the drawings, the same reference numerals denote the same elements or acts. The sizes and relative positions of the elements in the figures are not necessarily drawn to scale. For example, the shapes and angles of the corresponding elements are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to enhance the drawing's discernibility. Additionally, the specific shapes of the drawn elements are not intended to convey any information related to the actual shapes of the specific elements and are only selected for ease of identification in the figures.

[0005] Examples of waveguide reflector array projector (WRAP) systems are shown in the figures. The examples and figures are illustrative and not restrictive.

[0006] Figure 1A An exemplary convex spherical mirror is shown, which refocuses light focused at infinity at a specific radial distance.

[0007] Figure 1B-1 、 1B-2 FIGS. 1B-1, 1B-2, and 1B-3 show a conventional system that uses light-guide optical element (LOE) technology to project a single depth plane, with input light entering at three corresponding angles.

[0008] Figure 2A is a schematic diagram of an exemplary curved micro - reflector that is used to generate a spherical wavefront that appears to radiate from a virtual point source.

[0009] Figure 2B Shows exemplary relative orientation angles of micro - reflectors in a waveguide.

[0010] Figure 3A Shows an example layer in a waveguide reflector array projector.

[0011] Figure 3B Shows exemplary orientation angles of micro - reflectors in a waveguide.

[0012] Figure 3C Shows an exemplary curved micro - reflector.

[0013] Figure 4 Shows exemplary planar and spherical wavefronts.

[0014] Figure 5A is an isometric view of an optical device in the form of an exemplary multi - depth planar 3D display system or a waveguide reflector array projector (WRAP) device.

[0015] Figure 5B is a schematic diagram of a part of the optical device in FIG. 5, which, according to one of the illustrated embodiments, shows a plurality of waveguide layers that project light to produce corresponding virtual depth planes at corresponding radial distances that represent a plurality of virtual point sources to simulate a 4D light field.

[0016] Figure 5C is Figure 5A a schematic diagram of a part of the optical device in, which, according to one of the illustrated embodiments, shows a plurality of waveguide layers that project light to produce corresponding virtual depth planes that have spherical wavefronts at corresponding radial distances to simulate a 4D light field.

[0017] Figure 6 1]]Shows exemplary projection and propagation light cones of a WRAP system.

[0018] Figure 7 Shows an example of a reduced projection cone generated by a curved micro - reflector.

[0019] 8]] Figure 8 Shows an example of a multi - layer multiplexing system whose z - axis coupling tube is equipped with a light shutter.

[0020] Figure 9 Shows an exemplary illustration of light propagation through a WRAP system.

[0021] Figure 10 Shows the use of a deformable reflective surface for generating an exemplary wavefront.

[0022] Figure 11 An exemplary system using a transparent display screen is shown, the display screen having pixels that project light in a specified direction.

[0023] Figure 12 Is an exemplary illustration of how a three-dimensional volume is generated from a stack of two-dimensional projections.

[0024] Figure 13 Shows a coordinate system for virtual object points.

[0025] Figure 14 Shows a coordinate system for a 4D light field on a display surface.

[0026] Figure 15 Shows a coordinate system for two-dimensional microreflector orientation.

[0027] Figure 16 Shows an example of depth indexing for a two-dimensional light field.

[0028] Figure 17 Shows an example of a deformable microfluidic used as a microreflector.

[0029] Figure 18 Shows an example of an array of microreflectors with a function similar to a side-injected Fresnel mirror.

[0030] Figure 19 Shows an exemplary waveguide that generates a wide two-dimensional array of light beams from a single narrow light beam.

[0031] Figure 20 Shows an example of a light beam that must be wide enough to minimize gaps in the light beam array.

[0032] Figure 21 Is a flowchart showing an exemplary process of regenerating a three-dimensional volume on a display by driving a multi-layer waveguide in parallel. Detailed Description

[0033] Corresponding aspects and examples of the present invention will now be described. The following description provides specific details for a thorough understanding and to be able to describe these examples. However, those skilled in the art will understand that the present invention can be implemented without many of these details. In addition, certain well-known structures or functions are not shown or described in detail to avoid unnecessarily disturbing the relevant description.

[0034] The terms used in the following description are intended to be interpreted in the broadest reasonable manner, even when used in conjunction with the detailed description of certain specific examples of the present technology. Certain specific words may even be emphasized below; however, any term intended to be interpreted in a limiting manner will be explicitly and specifically so limited in the detailed description section.

[0035] The ability of the human perception to sense the depth of a field in a scene is limited, i.e., humans have limited visual resolution at different radial distances. Thus, in order to reproduce an object or a scene so that a user can experience a full 3D effect, not every possible focal plane in the 3D volume needs to be reproduced. The 3D volume can be reproduced for human perception by simply replicating a limited number of slices of a specific 3D volume. The theory related to the number of slices that need to be reproduced ranges from less than 16 to 36 or more, where the width of the slice is thinnest for distances close to the eye and increases with distance. The human visual system (i.e., the eye, the optic nerve, the brain) focally collapses each of these planes, so that humans do not need additional slices of the information shown to perceive the 3D volume. Independent of the actual number of slices required, the basic assumption is that only a limited number of slices of the 3D volume need to be replicated for humans to perceive a full 3D effect.

[0036] An optical device or system can be used, for example, to generate or project light to simulate a four-dimensional (4D) light field that can be generated by light reflected from a real three-dimensional object or scene. For example, an optical device such as a waveguide reflector array projector (WRAP) device or a multi-depth plane three-dimensional (3D) display system can generate or project a plurality of virtual depth planes at corresponding radial focal distances to simulate a 4D light field. An optical device in the form of a WRAP device or a multi-depth plane 3D display system can, for example, project an image directly or indirectly into each eye of a user. When the number and radial placement of the virtual depth planes are comparable to the depth resolution of the human visual system as a function of radial distance, the discrete set of projected depth planes mimics the psychophysiological effect produced by a real, continuous, three-dimensional object or scene.

[0037] As Figure 5A Best shown, an optical device in the form of a WRAP device or a multi-depth plane 3D display system 500 can include a 2D array 502 of a plurality of waveguides 504a - 504n (collectively denoted as 504, only two are shown for clarity of drawing). As shown, each waveguide 504 can have a rectangular cross-section through its length or its longitudinal axis (the longitudinal axis is denoted as the x-axis here). The waveguides 504 can be arranged in a plurality of columns 506 (e.g., in the xy plane extending vertically in the view of 5A, only one is shown for clarity of drawing) and rows 508 (e.g., in Figure 5AThe xz plane extending horizontally in the view, only one is shown for clarity of drawing). Column 506 can be characterized as a two-dimensional (2D) waveguide or a set of waveguides (each identified by reference numeral 506). The 2D waveguides 506 can be stacked into layers, for example, along the first horizontal axis represented here by the z-axis. As explained here, each 2D planar waveguide, set of waveguides, layer or column 506 generates a corresponding virtual depth plane at a corresponding distance to generate a 4D light field.

[0038] The WRAP device or multi-depth plane 3D display system 500 can include one or more components to provide one or more optical paths to or from the waveguide 504. For example, a set of distribution waveguides 510a - 510n (collectively denoted as 510, only two are shown for clarity of drawing). The distribution waveguides can provide optical paths to the waveguide 504 in each column or layer 506. Also for example, in a non-multiplexed implementation, the WRAP device or multi-depth plane 3D display system 500 can include a plurality of optical couplers (e.g., optical fibers) as indicated by arrows 512 (collectively referenced), which provide optical paths to the corresponding distribution waveguides 510 (i.e., each column 508). Also for example, in a multiplexed implementation, the WRAP device or multi-depth plane 3D display system 500 can include a single optical coupler (e.g., optical fiber) as indicated by arrow 514, which provides an optical path to two, more or all of the distribution waveguides 510. For example, the distribution waveguides 510 and / or the optical couplers 512, 514 can provide an input to the waveguides 504 of the 2D array 502, for example, as a pixel pattern from a red / green / blue (RGB) light source ( Figure 5A not shown in the figure).

[0039] [[ID=S]]As Figure 5B and 5C Best shown, each column or waveguide layer 506a - 506c (only three are shown, collectively denoted as 506) generates a corresponding segment or virtual depth plane 522a - 522c (only three are shown, collectively denoted as 522) having spherical wavefronts 524a - 524c (only three are shown, collectively denoted as 524) to cumulatively simulate the 4D light field 526. Also shown are the corresponding virtual point sources 528a - 528c (only three are shown, collectively denoted as 528) of each virtual depth plane 522a - 522c.

[0040] Figure 3AShows a single-column 2D planar waveguide, column, layer, or waveguide assembly 506 according to one illustrated embodiment, and its corresponding distributed coupler 510 and optical couplers 512, 514. Each 2D planar waveguide or layer 506 is composed of a plurality of linear waveguides 504e, 504f (collectively denoted as 504, only two are shown for clarity of drawing). Each 2D planar waveguide 506 may include, for example, a series or linear array of rectangular cylindrical waveguides 504, sometimes referred to as wave ducts. Although sometimes represented as "tubes", those skilled in the art will readily understand that such structures need not be hollow and will be solid in many embodiments, being in many respects similar to optical fibers but having at least a pair of opposing planar surfaces that are at least partially internally reflective to propagate electromagnetic energy (such as light) along the length 530 of the waveguide 504. As further explained herein, at least a pair of opposing planar surfaces 532a, 532b (collectively denoted as 532) may substantially internally reflect certain defined modes of light while allowing certain other defined modes of light to substantially pass outside the waveguide 504. Typically, the waveguide 504 will include two pairs of opposing planar surfaces 532a / 532b, 532c / 532d (collectively denoted as 532) that are partially internally reflective, for example, substantially internally reflecting certain defined modes. As used herein and in the claims, the term substantially means more than 50 percent, and typically more than 85 or 95 percent. The waveguides 504 of the 2D planar waveguide, layer, column, or assembly 506 may be formed separately and assembled or coupled together. Alternatively, the waveguides 504 of the 2D planar waveguide, layer, column, or assembly 506 may be formed as a single unitary structure. The planar surfaces may facilitate the generation of a desired depth plane and / or increase the density of stacking the waveguides 504 into a 3D structure.

[0041] Embedded, placed, or formed within each linear waveguide 504 is a series of dissected curved spherical reflectors or mirrors 540a - 540n (only two curved microreflectors are shown for clarity of drawing), which are designed to refocus light focused at infinity at a specific radial distance. It should be noted that for clarity of drawing, only the full microreflectors of a single linear array of only one linear waveguide 504 are shown in full with dashed lines, and the microreflectors of other linear arrays of other linear waveguides 504 are schematically represented by simple convex curves. Figure 5A Shows a plurality of microreflectors 504A - 504D for a single linear or rectangular waveguide 504n.

[0042] Figure 1AAn example is shown of how an input plane wave 100 focused at infinity can be reflected from a convex spherical mirror 102 to produce an output spherical wave 104 representing a virtual point source 106 that appears to be located at a defined distance behind the convex spherical mirror 102. By concatenating a series of microreflectors 540 in a (linear or rectangular) waveguide, the shape (e.g., the radius of curvature about two axes) and orientation of the microreflectors 504 together project a 3D image corresponding to the spherical wavefront produced by a virtual point source at specific x, y, z coordinates. Each 2D waveguide or layer 506 provides an independent optical path relative to the other waveguides and shapes and focuses the incoming light to project a virtual depth plane 522 corresponding to the respective radial distance ( Figure 5C ). With a sufficient number of 2D waveguides, a user viewing the projected virtual depth planes can experience a 3D effect.

[0043] A multi-layer 2D array 502 of planar waveguides 506 is described herein, where each layer projects light corresponding to a different virtual depth plane in a 3D volume. As explained above, Figure 5A-5C A portion of an exemplary multi-layer WRAP display device or system 500 is shown that has 2D planar waveguides, columns, or collections of waveguides 506 stacked as layers. Each layer 506 includes a plurality of waveguides, e.g., linear or rectangular waveguides 504 as shown in the example of Figure 3A . A collection of light distribution couplers 510 and / or other optical couplers 512, 514 optically couple the linear or rectangular waveguides 504 of the 2D array 502 to other components. For example, the light distribution couplers 510 and / or other optical couplers 512, 514 may optically couple the linear or rectangular waveguides 504 of the 2D array 502 to a subsystem that provides a pixel pattern (e.g., an RGB intensity modulated pixel pattern). In some cases, the collection of light couplers 510 is referred to herein and / or in the claims as a linear array of column distribution couplers or as a second transverse axis (Y) distributed optical coupler or coupling tube. As previously mentioned, those skilled in the art will readily understand that such structures need not be hollow and will be solid in many implementations, being similar in many respects to optical fibers.

[0044] Each individual waveguide 504 in the WRAP device 500 includes a series of dissected curved spherical reflectors or mirrors 540 that are designed to refocus light focused at infinity to a specific radial distance. A Fresnel lens is an example of a macroscopic optical element constructed from a series of optical microcomponents. The WRAP device 500 includes an array of microreflectors 540 that effectively act as Fresnel mirrors with side injection (e.g., side injection from what is represented as the first end). Figure 18An example of an array of micro - reflectors 1802a - 1802n (collectively denoted as 1802, only two are shown for clarity of drawing) in a spherical configuration of a portion of sphere 1804 is shown, rather than an array of micro - reflectors 1806a - 1806n (collectively denoted as 1806, only two are shown for clarity of drawing) in a linear configuration 1808 found in an equivalent Fresnel mirror, where the orientation of the micro - reflectors 1802 in the spherical configuration 1804 matches the orientation of the micro - components or micro - reflectors 1806 of the linear Fresnel mirror configuration 1808.

[0045] The WRAP device 500 includes an array of curved micro - reflectors in a linear or rectangular waveguide 504 containing each 2D waveguide 506. The array of curved micro - reflectors is positioned and oriented to act similarly to a lens or a curved mirror to project a virtual image at a specific radial distance. Although represented as "reflectors" here and / or in the claims, as explained here, the curved micro - reflectors typically partially reflect and partially transmit electromagnetic energy, e.g., light wavelengths of light (i.e., near - infrared light or N - IR, visible light, near - ultraviolet light or N - UV). As described here, the reflectivity can be a function of the angular mode of the electromagnetic energy or light.

[0046] Conventional lens - based imaging systems or curved - mirror - based imaging systems use optical elements with large surface curvatures. Conventional lens - based imaging systems or curved - mirror - based imaging systems are front - or back - illuminated, typically by a wide light field from a projector element. Such conventional systems tend to be relatively thick and heavy and typically use multiple optical elements and moving parts to change their focal lengths. In contrast, the 2D array 502 of linear waveguides 504 of the shown WRAP device 500 Figure 5A ) has a planar surface. The 2D array 502 of linear waveguides 504 of the shown WRAP device 500 can be side - illuminated (i.e., illuminated into the side represented by the first end here and in the claims) by a cone 542 of narrow - angle light beams from an optical fiber Figure 3A ), which is then internally multiplied into a wide light field. The 2D array 502 of linear waveguides 504 of the shown WRAP device 500 can be made thin and light. The shown 2D planar waveguides or layers 506 can be easily stacked to produce a multi - focal display, where each 2D planar waveguide, layer, column, or set 506 provides an independent optical path from the other 2D planar waveguides, layers, columns, or sets, e.g., allowing each to provide a corresponding focus or depth plane in a 3D image.

[0047] Contrary to the LOE system 10 as described above Figure 1B-1 、 1B-2 、1B - 3), in one embodiment, the WRAP device 500 projects multiple depth planes 522 Figure 5C), each focused at a different radial distance by a corresponding spherical wavefront curvature 524( Figure 5C ). The WRAP device 500 can include a series of linear or rectangular cylindrical waveguides arranged in vertical (xy) columns to produce a planar 2D waveguide 506, which in some cases can be referred to as a 2D assembly of linear or rectangular waveguides 503. The WRAP device 500 can include a plurality of 2D planar waveguides, columns, layers, or sets 506, each corresponding to a different virtual depth plane 522( Figure 5C ). The WRAP device 500 can use convex spherical bending microreflectors 540( Figure 3A and 5A ). The microreflectors 540 can have one or more surface curvatures, and the surface curvature can vary in each waveguide layer 506. As Figure 3B and 3C best shown, each microreflector 540 can be oriented along two angular directions θ. The angular direction θ can vary in any given linear waveguide 504, or can vary between linear waveguides 504 in a single layer 506 or between different layers 506.

[0048] As Figure 8 best shown, for example, a separate set of optional optical demultiplexing switches implemented by one or more light intensity modulators 546, fiber optic cables 548, angular mode modulators or beam deflectors 550, optional z-axis coupling arrays 554, and the y-axis optical couplers or optical coupling arrays 510 described and shown previously, can couple light (e.g., pixel patterns) from one or more RGB (red, green, blue) light sources 544 into the 2D array 503 of the WRAP device 500.

[0049] What is WRAP

[0050] The WRAP device 500 can include a stack of thin planar 2D waveguides 506, which are themselves composed of horizontal rows of linear or rectangular cylindrical waveguides 504. Although represented as 2D, the 2D waveguides 506 physically have depth, but are represented as such because each represents a 2D slice or portion (i.e., column) of the 2D array 502. Although represented as 2D, the 2D array of waveguides physically has depth, but is represented as such because the length is an inherent property of the individual linear or rectangular waveguides 504 that make up the 2D array 502. Similarly, although sometimes referred to as linear waveguides 504, these waveguides physically have height and width, but are represented as such because each provides a linear optical path.

[0051] Figure 3AShows an exemplary single-layer 2D array 503 of the WRAP device 500. The input cone 542 of light is directed into a distribution optical coupler or y-axis optical coupler 510 through optical fibers 512, 514, 548. The distribution optical coupler or y-axis optical coupler is sometimes referred to herein as a coupling tube (vertically oriented in Figure 3A ). Mounted in rows within the optical coupler 510 are a plurality of beam splitters 556a - 556n (collectively denoted as 556, only two are shown for clarity of drawing). Each beam splitter 556 reflects a first portion of the light incident thereon into one of a plurality of stacked linear or rectangular waveguides 504 (horizontally oriented in Figure 3A ), and transmits a second portion of the light to the next beam splitter 556. Thus, the light incident on the distribution optical coupler or y-axis optical coupler 510 is emitted into a plurality of linear or rectangular waveguides 504 positioned along at least a portion of the length of the distribution optical coupler or y-axis optical coupler 510.

[0052] As previously explained, embedded, positioned, or formed within each linear or rectangular waveguide 504 is a linear array of curved microreflectors 540, which are shaped and angularly oriented such that, through the microreflectors 540, each angled light beam guided through the linear or rectangular waveguide 504 is projected into a three-dimensional curved pattern. Figure 3B Shows an exemplary orientation angle θ of the microreflector 540 in the waveguide, where, for simplicity of illustration, the microreflector is shown in a planar form. Figure 3C Shows an example of the orientation angle θ for the curved microreflector 540. The projected pattern corresponds to a spherical wavefront generated by a virtual point source placed at given x, y, z coordinates, where the x and y coordinates are determined by the 2D angular orientation of the light beam, and the z coordinate is determined by the specific configuration of the microreflectors and the 2D orientation gradient in a given 2D planar waveguide, column, layer, or set 506. Each 2D planar waveguide, column, layer, or set 506 is configured to have a different wavefront shape and focusing property, such that each layer projects a virtual depth plane corresponding to a different z coordinate or radial coordinate (r coordinate).

[0053] A point source of light placed at given x, y, z coordinates generates a three-dimensional radiation pattern of light that changes in a very specific manner throughout the three-dimensional space. In particular, the point source generates a spherical wavefront, the surface curvature of which changes inversely with the radius of the radiation sphere. The WRAP device 500 is designed to generate a portion of the sphere with a suitable wavefront curvature and two-dimensional rotation for a specific z coordinate upon receiving an input light ray corresponding to given x, y coordinates.

[0054] How WRAP works

[0055] As Figure 3A illustrated by the example of, light input to each WRAP 2D planar waveguide, column, layer, or set 506 can be provided by a separate multimode optical fiber 512 into which a small cone 542 of light has been injected. Alternatively, the light input to each 2D planar waveguide, column, layer, or set 506 is in the form of a cone 542 of light through corresponding input channels 514 of a demultiplexing switch 552( Figure 8 ). The cone 542 of light contains a two-dimensional angular distribution of the light beam that corresponds to the two-dimensional x, y light intensity pattern present in a single depth plane of the 3D volume to be recreated. There are various ways to couple the angular distribution of the light cone into the input optical fiber, for example, using a MEMS scanner, switchable liquid crystal, or MEMS diffraction grating.

[0056] The propagating light cone 542 should have a defined or known angular pattern, for example, as Figure 6 illustrated by the example of. In some embodiments, the light cone 542 propagating inside the linear or rectangular waveguide 504 should be generally in two angular directions within an angular range of approximately -22.5 degrees to -67.5 degrees, and the light cone 560 projected outside the waveguide should be generally in two angular directions within an angular range of approximately -22.5 degrees to +22.5 degrees. Significantly, within a relatively narrow angular range of the light rays, propagation will occur in the waveguide, and thus the angular range of the input image should be correspondingly restricted. Light propagating outside these angular ranges will produce confusion and ghosting.

[0057] There are two ways to drive the 2D planar waveguides, columns, sets, or multiple layers 506 in the 2D array 502, either in parallel or serially. In the parallel method (as Figure 5A illustrated by the example of), each waveguide layer 506 is driven by a different multimode optical fiber 512 that propagates an angular pattern corresponding to a portion of the visual field contained in a specific depth layer volume. These angular patterns are generated by driving electronics (such as RGB light sources, intensity modulators) located in the base unit and then sent to the 2D array 502 in parallel through multiple multimode optical fibers 512. For example, a scanning projector system (such as a scanning fiber projector) can be used or the 2D image can be angularly encoded by coupling a 2D micro-projector to a pinhole aperture.

[0058] In the serial method (as Figure 8 illustrated by the example of), the angular pattern of the entire visual field is generated simultaneously and sorted between different waveguide layers 506, one angular beam at a time, using a shutter 552 synchronized with the 2D beam deflector 550 that generates the pattern. Since this process is in the 2D array, distribution, or y-axis optical coupler 510 and / or z-axis optical coupler 562( Figure 9) It is carried out in the intermediate unit rather than in the basic unit, and it can be driven by a single single-mode optical fiber 514. In this system, the input image is angle-encoded so that each resolvable angle that propagates through the optical fiber or other waveguide 514 corresponds to the intensity of a single object point. To encode the image in this way, a multimode optical fiber 514 and optical couplers 514, 562 are used, which can propagate multiple angular modes at an angular density comparable to the linear resolution of the display. The angular range of the light cone corresponds to the maximum field of view of the optical device 500, for example, 45 degrees.

[0059] [[ID=**3**]] Figure 9 An exemplary illustration of light propagation through a partial WRAP device is shown, which includes a z-axis optical coupler 562. Figure 9 The relative orientation of the z-axis optical coupler 562, the distributed or y-axis optical coupler 510, and the linear or rectangular waveguide (alternatively referred to as the x-axis waveguide) 504 is shown. In Figure 9 the embodiment, light initially enters through the z-axis optical coupler 562. The z-axis optical coupler can be similar to a linear or rectangular waveguide in many aspects. For example, it has at least a pair of opposite planar sides that provide at least partial internal reflection to propagate or guide light along the length of the z-axis optical coupler 562. The z-axis optical coupler 562 includes a linear array of angled planar microreflectors 564a - 564n (collectively denoted as 564), which multiply and inject copies of the incident angle distribution of the light into the distributed or y-axis optical coupler 510 of the corresponding column, set, or layer 506. The distributed or y-axis optical coupler 510 can be similar in construction to the z-axis optical coupler 562, having a linear array of angled planar microreflectors 566a - 566n (collectively denoted as 566). The distributed or y-axis optical coupler 510 multiplies and injects copies of the incident angle distribution of the light into each x-axis waveguide 504 in the corresponding column, set, or layer 506.

[0060] As Figure 2A shown, a narrow angled planar wave beam 566 enters the linear or rectangular waveguide 504 and is reflected from the planar reflector 568 towards at least one of the opposite reflective surfaces 532. When each narrow angled planar wave beam propagates through the waveguide and hits the curved microreflector 540, the planar wave beam is divided into two beams. Also as Figure 2AAs shown, the first light beam continues to the next micro - reflector 540, and the second light beam is reflected in a divergent pattern having a curvature twice as large as the curvature of the surface of the micro - reflector 540 that reflects the second light beam. In other words, a narrow incident plane wave is converted into a small wedge - shaped portion with a spherical wavefront having a 2D orientation corresponding to the orientation of the incident plane wave. If the 2D orientations of all the curved micro - reflectors 540 in the 2D waveguide, column, set, or layer 506 vary in a very precise manner, all the spherical wavefront wedges projected from each micro - reflector 540 can be aligned into a single spherical wavefront 569 that appears to radiate from a virtual point 570 located at x and y coordinates and a z coordinate, where the x and y coordinates correspond to the 2D orientation of the plane wave 566, and the z coordinate corresponds to the curvature of the micro - reflector 540 and the 2D orientation gradient of the 2D waveguide, column, set, or layer 506, as Figure 2B shown. For reference, Figure 13-15 the coordinate system of the virtual object point, the 4D light field of the display surface, and the 2D micro - reflector orientation are shown respectively.

[0061] When all the angled plane - wave light beams in the input cone propagate through the 2D waveguide, plane, set, or layer 506, the light beams reproduce an overlapping light field generated by a single depth plane. When all the input signals of each 2D waveguide, plane, set, or layer 506 propagate through the 2D array 502, they replicate an overlapping light field generated by a volume of multiple depth planes. If these depth planes are numerous enough and have a suitable thickness as a function of their radial distance (determined by the field - depth equation), such that if the depth planes meet or exceed the limits of human z - coordinate resolution (as well as x, y coordinate resolution), then for a human, the light field generated from the virtual 3D volume should be indistinguishable from the light field from a real, physical, three - dimensional space.

[0062] Due to the unique optical properties of the materials used in the optical system 500 (as described here), each 2D waveguide, plane, set, or layer 506 does not affect the others. This feature allows the 2D waveguides, planes, sets, or layers 506 to be stacked on top of each other to produce a multi - focal optical system, a feature that is considered impossible in traditional lenses.

[0063] In addition, orthogonal light polarization can be used to decouple light from the real external world from the light of the virtual display to produce an enhanced reality multi-depth plane 3D display. The polarized reflector 540 reflects only the portion of the light that is aligned parallel to the polarization axis of the reflector. Cross-polarized light is not reflected by the reflector 540 and, in the case of the semi-transparent reflector 540, will simply pass through the reflector without being reflected. In this way, by simply cross-polarizing the light of the 2D waveguide, plane, set, or layer 506, the 2D waveguide, plane, set, or layer 506 can become transparent to light from the external world or to other 2D waveguides, planes, sets, or layers 506.

[0064] If the 2D light pattern 1602 is generated in a chronological manner, it corresponds to the radial pinhole projection of the entire virtual 3D volume 1604, and each point in the 2D field is depth-indexed, such as as Figure 16 shown, then as Figure 8 shown, the z-axis optical coupler 562 ( Figure 9 ) can be equipped with a light shutter 522 that is synchronized with the beam deflector 550 to sort the light beams from the multiplexed input cone 542 into a plurality of output channel cones 572 corresponding to each depth plane in the virtual 3D volume 1604 (only one is shown in Figure 8 for clarity of drawing).

[0065] In a serial method for driving the different 2D waveguides, planes, sets, or layers 506 of the 2D array 502 discussed above, the 2D array 502 is driven by a single single-mode optical fiber 514, 548, and the optical cones 572 corresponding to the different 2D waveguides, planes, sets, or layers 506 are generated within the device itself. The light angles should be generated and sorted simultaneously, one angle at a time. If the light angles are not generated in a chronological manner, they cannot be easily sorted for each 2D waveguide, plane, set, or layer 506.

[0066] Mathematical Observation

[0067] The optical device 500 can be regarded as a mathematical operator that transforms a 2D light field into a 4D light field. Figure 4 Exemplary details of the transformation are shown. The optical device 500 performs this transformation by applying positive curvature to each light beam in the input optical cone 402 and mapping 406 a 2D array of differentially rotated copies of the adjusted optical cone to the surface of the display. These operations are physically generated by the array of micro-reflectors 540 and have the effect of transforming a narrow plane wave light beam into a wide spherical wavefront 404; converting the optical cone into a virtual depth plane; and generating a 3D volume from a stack of two-dimensional projections, as in the example of Figure 12 shown. (For comparison, Figure 4 and12 An input cone 408 that is generated as a planar wavefront 410 is also shown. Figure 13 A coordinate system 1300 of a virtual object point is shown. Figure 14 A coordinate system 1400 of a 4D light field on a display surface is shown. Figure 15 A coordinate system 1500 of a two-dimensional micro-reflector orientation is shown.

[0068] In the context of the optical device 500, a linear or rectangular waveguide 504 serves as a beam multiplier or expander that mathematically and physically generates a wide 2D array of light beams based on a single narrow light beam. Figure 19 Shows how to multiply a light cone 1902a - 1902d (collectively denoted as 1902) by using multiple beam splitters that transmit a portion of the incident light and reflect a portion of the incident light.

[0069] Exemplary system description:

[0070] The micro-reflector (e.g., the curved micro-reflector 504) should be partially transparent and perform the functions of a beam splitter as well as a reflector. In this way, a single light beam with a narrow angular range can be repeatedly multiplied and redistributed through an array to produce a wide 4D light field.

[0071] Furthermore, the reflectivity of the reflective surface (e.g., 532) of the waveguide (e.g., the linear or rectangular waveguide 504) and the micro-reflector (e.g., the curved micro-reflector 504) should be angle-specific. In particular, the micro-reflector (e.g., the curved micro-reflector 504) should only reflect the angular mode of the input cone that is internally reflected from the surface (e.g., 532) of the waveguide (e.g., the linear or rectangular waveguide 504) and should be transparent to all other angular modes. Each waveguide (e.g., the linear or rectangular waveguide 504) should only be transparent to the angular mode reflected from the micro-reflector (e.g., the curved micro-reflector 504) and should confine all other angular modes within the waveguide (e.g., the linear or rectangular waveguide 504). This allows the light from the input cone to be distributed along the entire length of the waveguide (e.g., the linear or rectangular waveguide 504) and coupled to each micro-reflector (e.g., the curved micro-reflector 504) before being projected outside the 2D array 502. This also avoids light hitting the micro-reflector (e.g., the curved micro-reflector 504) from two opposite surfaces (e.g., 532) of the waveguide (e.g., the linear or rectangular waveguide 504), which would result in a double set of images instead of a single set of images.

[0072] This would limit the field of view. For example, this limits the field of view to a maximum field of view (FOV) of 45 degrees 700( Figure 7)。Out of the total possible 360 degrees of angles that can propagate in the waveguide, half of those angles (180 degrees) propagate in the wrong direction (out of rather than into the waveguide), another 45 degrees correspond to the field of view projected by the microreflector, and another 45 degrees correspond to the angular offset light cone propagated by the waveguide before the light cone hits the microreflector. The remaining 90 degrees do not seem to be useful because these angles would create confounding effects from secondary reflections off the outer surface of the waveguide, as Figure 6 shown. In practice, the field of view 700 of the optical device 500 will be less than 45 degrees to accommodate the beam curvature created by the microreflector 540, as Figure 7 shown.

[0073] The light beam coupled into the linear or rectangular waveguide 504 should be wide enough so that the microreflector 540 is evenly covered by the light beam and gaps and irregularities in the output are minimized. Figure 20 An example is shown where the width of the light beam 2002 is not wide enough to prevent gaps in the light beam array.

[0074] In order for the display to function as an augmented reality device, the light from the input cone should be polarized along a single axis, and the microreflector 540 and the reflective opposing surfaces 532 of the waveguide 504 should only reflect light rays polarized along the same axis. Additionally, the outer side of the display should have an orthogonal polarization screen (not shown), such as a liquid crystal display, which allows the user to adjust the real-virtual contrast, i.e., the relative light intensity of the real and virtual visual fields. The orthogonal polarization screen can also orthogonally polarize the light from the real world with respect to the polarization axis of the virtual display, thereby allowing light rays to pass through the display without being affected by the microreflector 540 or the reflective opposing surfaces 532 of the linear or rectangular waveguide 504.

[0075] Furthermore, any phase differences and incoherencies introduced by variations in path length, transit time, and wavelength should not be perceivable by the human visual system.

[0076] To be thin enough to be a wearable device, each 2D planar waveguide, column, set, or layer 506 in the 2D array 502 should be as thin as possible. For example, in one embodiment with 10 layers, a thickness of approximately 1 mm per layer can be used for the wearable device. Using a larger number of layers, such as 25 to 35 layers, the near and far light fields can be fully recreated. However, less than 10 or more than 35 layers can be used.

[0077] In some implementations, each 2D planar waveguide, column, set, or layer 506 can be reconfigured in real time, i.e., the curvature and / or 2D orientation gradient of the microreflector 504 can be dynamically changed in a rapid manner. Using such implementations, the projection of each virtual depth layer can be time-multiplexed rather than being presented simultaneously. For this purpose, the single-layer N-plane display system should be reconfigured at a rate N times the refresh rate of a single layer in the N-layer system. Dynamically configurable curved microreflectors 504a ( Figure 10 ) can be employed. For example, a two-dimensional liquid crystal surface can be used, where the shape and orientation of the surface can be controlled by an electric and / or magnetic field, as shown in the example of Figure 10 . Alternatively, electro- and / or magneto-deformable microfluidics can be used as the microreflector 504b, where the shape and orientation can be dynamically changed, as shown in the example of Figure 17 .

[0078] In some embodiments, a transparent display screen whose pixels 540b are capable of projecting light in a specific direction can be used to change the direction of the projected light, e.g., as shown in the examples of Figure 10 bottom and Figure 11 .

[0079] Operation WRAP

[0080] Figure 21 is a flowchart showing an exemplary process 2100 for regenerating a three-dimensional volume on a display by driving multiple layers of waveguides in parallel. At block 2105, the optical device 502 receives a plurality of input beams. Each of the plurality of beams can be delivered by a multimode optical fiber. Each of the plurality of input beams corresponds to an intensity pattern of a portion of the visual field in a different layer of the three-dimensional volume to be regenerated.

[0081] Then at block 2110, the system generates a set of intermediate beams from each of the plurality of input beams.

[0082] Next, at block 2115, the system independently rotates copies of the set of the plurality of intermediate beams, and at 2120, projects wavefronts that appear to radiate from a virtual point. All the projected wavefronts together regenerate the 3D volume for the user to view.

[0083] Conclusion

[0084] Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense (i.e., "including but not limited to") rather than an exclusive or exhaustive sense. As used herein, the term "connected", "coupled", or any of its equivalents refers to any direct or indirect connection or coupling between two or more elements. Such a coupling or connection between elements can be physical, logical, or a combination thereof. Further, when used in this application, the words "herein", "above", "below", and words of similar import refer to the entire application rather than to any particular part of the application. Where context permits, the words in the above Detailed Description section in singular or plural form may also respectively include the plural or singular form. In a list referring to two or more items, the word "or" encompasses all of the following interpretations of the word: any item in the list, all items in the list, and any combination of items in the list.

[0085] The above Detailed Description section of the examples of the present invention is not intended to be exhaustive or to limit the invention to the specific forms disclosed herein. Although specific examples of the invention are described herein for illustrative purposes, those skilled in the art will recognize that various equivalent modifications within the scope of the invention are possible. Although the processes or blocks are shown in a given order in this application, alternative implementations may perform the steps in a different order, or systems with blocks in a different order may be employed. Some processes or blocks may be deleted, moved, added, subdivided, combined, and / or modified to provide alternative or sub-combinations. Also, although the processes or blocks are sometimes shown as being performed serially, these processes or blocks may be performed or implemented in parallel or may be performed at different times. Further, any specific numbers noted herein are merely examples. It will be understood that alternative implementations may employ different values or ranges.

[0086] The various instructions and teachings provided herein can also be applied to systems other than the systems described above. The elements and actions of the various examples above can be combined to provide further implementations of the present invention.

[0087] Any patents and applications and other references mentioned above, including any documents listed in the accompanying application files, are hereby incorporated by reference. Where necessary, aspects of the present invention may be modified to incorporate the systems, functions, and concepts included in such references to provide further implementations of the present invention.

[0088] These and other changes may be made under the teachings of the above detailed embodiments. Although the above description describes some examples of the invention and describes the best mode contemplated, the invention may be implemented in many different ways regardless of how detailed the above description appears in the text. The details of the system may vary significantly in its specific implementation, although it is still encompassed by the invention disclosed herein. As noted above, when describing certain features or aspects of the invention, the specific terms used should not be construed as implying that the terms are hereby redefined to limit any specific characteristics, features, or aspects of the invention related to that term. Generally, the terms used in the appended claims should not be construed as limiting the invention to the specific examples disclosed in the specification unless the above detailed embodiments section specifically defines these terms. Thus, the actual scope of the invention includes not only the disclosed examples, but also all equivalent ways of practicing or implementing the invention in accordance with the claims.

[0089] Although the specific scope of the invention is shown below in the form of specific claims, the applicant contemplates various aspects of the invention in any number of claim forms. For example, although only one aspect of the invention is recited as an apparatus-plus-function claim under 35 U.S.C. § 112, sixth paragraph, other aspects may be similarly implemented as apparatus-plus-function claims, or in other forms, such as being implemented on a computer-readable medium. (Any claim treated under 35 U.S.C. § 112, sixth paragraph will begin with the words "means for"). Thus, the inventors reserve the right to add additional claims after the filing of the application to pursue such additional claim forms for other aspects of the invention.

[0090] U.S. Patent Application 61 / 658355, filed on June 11, 2012, is hereby incorporated by reference in its entirety.

Claims

1. A method for reproducing a three - dimensional volume for viewing by a waveguide reflective array projector device, the method comprising: Receiving, by the waveguide reflective array projector device, a plurality of input light beams, wherein each input light beam is in the form of a light cone including a two - dimensional angle of the light beam, and the two - dimensional angle distribution corresponds to a two - dimensional x, y light intensity pattern in a single depth plane of the three - dimensional volume; Generating, by the waveguide reflective array projector device, from each of the plurality of input light beams, a set of a plurality of intermediate light beams, the set of intermediate light beams including an overlapping light field generated by the single depth plane; Independently rotating, by the waveguide reflective array projector device, a copy of each set of the plurality of intermediate light beams and projecting a wavefront that appears to radiate from a virtual point of each set; Wherein the projected wavefronts together reproduce the three - dimensional volume.

2. The method according to claim 1, wherein The plurality of input light beams include light having an angular range.

3. A method for reproducing a three - dimensional volume for viewing by a waveguide reflective array projector device, the method comprising: Receiving, by a single single - mode optical fiber of the waveguide reflective array projector device, time - multiplexed input light, wherein the received input light beam corresponds to an intensity pattern of a portion of the visual field of a plurality of depth planes of the three - dimensional volume; Transferring the received time - multiplexed input light to a z - axis optical coupler of the waveguide reflective array projector device, the z - axis optical coupler including a planar micro - reflector; Transferring, by the z - axis optical coupler, a portion of the received time - multiplexed input light to a corresponding coupler in a set of y - axis distributed optical couplers of the waveguide reflective array projector device, the y - axis distributed optical couplers including planar micro - reflectors; Transferring, by the y - axis optical coupler, a portion of the received time - multiplexed input light to a corresponding set of waveguides of the waveguide reflective array projector device; and Projecting, by the waveguides in at least some of each set of the sets of waveguides, at least a portion of the received time - multiplexed input light, wherein each set of waveguides projects a corresponding virtual depth plane, and the cumulative virtual depth planes form the three - dimensional volume for viewing.

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