HK40031016A - Multibeam element-based near-eye display, system, and method - Google Patents

Description

Near-eye display, system, and method based on multi-beam elements

Cross Reference to Related Applications

N/A

Statement regarding federally sponsored research or development

N/A

Background

For users of a wide variety of devices and products, electronic displays are an almost ubiquitous medium for conveying information to users. Among the most common electronic displays are Cathode Ray Tubes (CRTs), Plasma Display Panels (PDPs), Liquid Crystal Displays (LCDs), electroluminescent displays (ELs), Organic Light Emitting Diodes (OLEDs), and Active Matrix Organic Light Emitting Diodes (AMOLEDs), electrophoretic displays (EPs), and various displays using electromechanical or electrofluidic light modulation (e.g., digital micromirror devices, electrowetting displays, etc.). In general, electronic displays may be classified as either active displays (i.e., displays that emit light) or passive displays (i.e., displays that condition light provided by another light source). Among the categories of active displays, the most obvious examples are CRT, PDP, and OLED/AMOLED. In the case of the consideration of the emitted light, LCD and EP displays are generally classified as passive displays. Passive displays, while often exhibiting attractive performance characteristics including, but not limited to, inherent low power consumption, may have limited use in many practical applications due to their lack of ability to emit light.

In addition to being categorized actively or passively, the features of the electronic display may also be determined based on the expected viewing distance of the electronic display. For example, most electronic displays are designed to have to be placed in a normal or "natural" range of accommodation at a distance from the human eye. Thus, such an electronic display may be viewed directly and naturally by a user without the need for additional optical elements. On the other hand, some displays are specifically designed to be placed closer to the human eye than the normal adjustment range. These electronic displays are often referred to as "near-eye" displays and typically include some form of optical element to facilitate viewing by a user. For example, the optical element can provide a virtual image of a physical electronic display that is within a normal range of adjustment, so that a user can still comfortably view the physical electronic display even though the user cannot directly view the display. Examples of applications using near-eye displays include Head Mounted Displays (HMDs), similar wearable displays, and some Head-up displays; examples of near-eye displays are not limited thereto. Since near-eye displays may provide a user with a more immersive experience than conventional displays, various Virtual Reality (VR) systems and Augmented Reality (AR) systems often include near-eye displays as well.

Drawings

Various features of examples and embodiments in accordance with the principles described herein may be more readily understood with reference to the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals identify like structural elements, and in which:

FIG. 1A illustrates a perspective view of a multi-view display in an example, according to an embodiment consistent with principles described herein.

FIG. 1B illustrates a schematic diagram of the angular components of a light beam having a predominant angular direction for a multi-view display in an example, according to an embodiment consistent with the principles described herein.

Figure 2 illustrates a cross-sectional view of a diffraction grating in an example, according to an embodiment consistent with the principles described herein.

Fig. 3 illustrates a block diagram of an example of a near-eye display in an example, according to an embodiment consistent with the principles described herein.

Fig. 4 illustrates a schematic diagram of an example of an optical element of a near-eye display in an example, according to an embodiment consistent with the principles described herein.

Fig. 5 illustrates a cross-sectional view of an example of a near-eye display having an optical system including a freeform prism in an example, according to an embodiment consistent with the principles described herein.

Fig. 6A illustrates a cross-sectional view of an example of a multibeam element-based display in an example, according to an embodiment consistent with the principles described herein.

Fig. 6B illustrates a plan view of a multibeam element-based display in an example, according to an embodiment consistent with the principles described herein.

Fig. 6C illustrates a perspective view of a multibeam element-based display in an example, according to an embodiment consistent with the principles described herein.

Fig. 7A illustrates a cross-sectional view of a portion of a multibeam element-based display including a multibeam element in an example, according to an embodiment consistent with the principles described herein.

Fig. 7B illustrates a cross-sectional view of a portion of a multibeam element-based display including a multibeam element in an example, according to an embodiment consistent with the principles described herein.

Figure 8A illustrates a cross-sectional view of a diffraction grating including a plurality of sub-gratings in an example, according to an embodiment consistent with the principles described herein.

Figure 8B illustrates a plan view of the diffraction grating of figure 6A in an example, according to an embodiment consistent with the principles described herein.

FIG. 9 illustrates a plan view of a pair of multibeam elements in an example, according to an embodiment consistent with principles described herein.

Fig. 10A illustrates a cross-sectional view of a portion of a multi-beam display including a multi-beam element in an example, according to another embodiment consistent with principles described herein.

Fig. 10B illustrates a cross-sectional view of a portion of a multibeam element-based display including a multibeam element in an example, according to an embodiment consistent with the principles described herein.

Fig. 11 illustrates a cross-sectional view of a portion of a multi-view backlight panel including a multibeam element in an example, according to an embodiment consistent with principles described herein.

Fig. 12 illustrates a block diagram of a binocular near-eye display system in an example, according to an embodiment consistent with the principles described herein.

Fig. 13 illustrates a flow chart of a method of operation of a near-eye display in an example, according to an embodiment consistent with the principles described herein.

Some examples and embodiments have other features in addition to, or instead of, those shown in the above-referenced figures. These and other features will be described in detail below with reference to the above-identified figures.

Detailed Description

The following embodiments and examples provide a near-eye image display capable of providing an adjustment support function (adaptation support) according to the principles of the present invention. In particular, according to various embodiments of the principles described herein, the present invention provides a near-eye display that employs a multi-view display to generate multiple different views of an image. A plurality of different views are projected or arranged into different positions in an eye box (eye box) where a near-eye multi-view image is viewed. According to various embodiments, different views at different locations may support accommodation functions with respect to the multi-view image (i.e., to help focus the eye on an object).

In this context, a "two-dimensional display" or "2D display" is defined as a display that provides an image whose view is substantially the same regardless of the direction from which the image is viewed (i.e., within a predetermined viewing angle or 2D display range). Liquid Crystal Displays (LCDs) that may be found in smart phones and computer screens are examples of 2D displays. In contrast, a "multi-view display" is defined as an electronic display or display system configured to provide different views (differential views) of a multi-view image (multiview image) in or from different view directions. In particular, the different views may represent different perspective views of a scene or object of the multi-view image. In some cases, a multiview display may also be referred to as a three-dimensional (3D) display, e.g., providing the sensation of viewing a three-dimensional image when two different views of the multiview image are viewed simultaneously.

Fig. 1A illustrates a perspective view of a multi-view display 10 in an example, according to an embodiment consistent with principles described herein. As shown in fig. 1A, the multi-view display 10 includes a screen 12 for displaying or providing a multi-view image to be viewed. The multi-view display 10 provides different views 14 of the multi-view image in different view directions 16 relative to the screen 12. The view direction 16 extends from the screen 12 in various different principal angular directions, as indicated by the arrows. The different views 14 are shown as shaded polygonal boxes at the end of the arrows (i.e., representing view directions 16), and only four views 14 and four view directions 16 are shown, all by way of example and not limitation. It is noted that although the different views 14 are depicted in fig. 1A as being above the screen, when the multi-view image is displayed on the multi-view display 10, the views 14 actually appear on or near the screen. The depiction of the views 14 above the screen 12 is merely for simplicity of illustration and is intended to represent viewing of the multi-view display 10 from a respective one of the view directions 16 corresponding to a particular view 14.

A view direction, or equivalently a light beam having a direction corresponding to the view direction of a multi-view display, generally has a main angular direction given by the angular components theta, phi, according to the definition herein. The angular component θ is referred to herein as the "elevation component" or "elevation angle" of the light beam. The angular component φ is referred to as the "azimuth component" or "azimuth" of the beam. By definition, the elevation angle θ is an angle in a vertical plane (e.g., perpendicular to the screen plane of the multiview display) and the azimuth angle is an angle in a horizontal plane (e.g., parallel to the screen plane of the multiview display).

FIG. 1B illustrates a schematic diagram of angular components { θ, φ } of a light beam 20 having a particular principal angular direction, or simply "direction", corresponding to a view direction (e.g., view direction 16 in FIG. 1A) of a multi-view display, in an example, according to an embodiment consistent with the principles described herein. Further, the light beam 20 is emitted or emitted from a particular point, as defined herein. That is, by definition, the light beam 20 has a central ray associated with a particular origin within the multi-view display. Fig. 1B also shows the beam (or view direction) at the origin O.

Further, in this document, the term "multi-view" as used in the terms "multi-view image" and "multi-view display" is defined as a plurality of views representing different viewing angles or including angular differences between views among the plurality of views (views). In addition, as defined herein, the term "multi-view" herein expressly includes more than two different views (i.e., a minimum of three views and often more than three views). As such, the term "multi-view display" as used herein is expressly distinguished from stereoscopic displays that include only two different views representing a scene or image. It should be noted that although the multi-view image and the multi-view display may include more than two views, the multi-view image may be viewed on the multi-view display as a stereoscopic image pair (e.g., one view per eye) by selecting only two of the multi-views at a time, as defined herein.

According to the definition of the invention, the term "multi-view pixel" is defined as a group of sub-pixels or a group of "view" pixels in each of a similar plurality of different views of the multi-view display. In particular, a multi-view pixel may have individual view pixels that correspond to or represent view pixels in each of the different views in the multi-view image. Furthermore, the view pixels of a multi-view pixel are, by definition herein, so-called "directional" pixels, in that each view pixel is associated with a predetermined view direction of a respective one of the different views. Furthermore, according to various examples and embodiments, different view pixels of a multiview pixel may have identical or at least substantially similar positions or coordinates in each different view. For example, the first multi-view pixel may have an individual view pixel located { x ] in each different view of the multi-view image₁,y₁At (c) }; while the second multi-view pixel may have an individual view pixel located { x ] in each different view of the multi-view image₂,y₂At, and so on.

In some embodiments, the number of view pixels in a multi-view pixel may be equal to the number of different views of the multi-view display. For example, the multiview pixel may provide sixty-four (64) view pixels, the sixty-four (64) view pixels being associated with a multiview display having sixty-four (64) different views. In another example, the multiview display may provide an eight by four array of views (i.e., 32 views), and the multiview pixels may include 32 view pixels (i.e., one for each view). Further, for example, each of the different view pixels may include an associated direction (e.g., a beam direction) corresponding to a different view direction of a plurality of view directions corresponding to 64 different views. Further, according to some embodiments, the number of multiview pixels of the multiview display may be substantially equal to the number of pixels of the multiview display (i.e. the pixels constituting the selected view). For example, if a view includes six hundred forty by four hundred eighty view pixels (i.e., a view resolution of 640x 480), a multiview display may have thirty-zero seven thousand two hundred (307,200) multiview pixels. In another example, when a view includes one hundred by one hundred pixels, a multiview display may include a total of ten thousand (i.e., 100x 100 ═ 10,000) multiview pixels.

Herein, a "lightguide" is defined as a structure that guides light within the structure using Total Internal Reflection (TIR). In particular, the light guide may comprise a core that is substantially transparent at the operating wavelength of the light guide. In various examples, the term "light guide" generally refers to a dielectric optical waveguide that utilizes total internal reflection to guide light at an interface between a substance of the dielectric material of the light guide and a substance or medium surrounding the light guide. By definition, the condition for total internal reflection is that the refractive index of the light guide is greater than the refractive index of the surrounding medium adjacent to the surface of the light guide material. In some embodiments, the light guide may include a coating in addition to, or in place of, the aforementioned difference in refractive index, thereby further contributing to total internal reflection. For example, the coating may be a reflective coating. The light guide may be any of several light guides including, but not limited to, one or both of a flat plate (plate) or slab (slab) light guide and a strip light guide.

Further, in the present disclosure, the term "slab," as applied to light guides, such as a "slab light guide," is defined as a layer or sheet of piecewise linear or differential ground plane (differential planar), which is sometimes referred to as a "slab" light guide. In particular, a slab light guide is defined as a light guide configured to guide light in two substantially orthogonal directions bounded by a top surface and a bottom surface (i.e., opposing surfaces) of the light guide. Further, by definition herein, the top and bottom surfaces are both separate from each other and may be substantially parallel to each other in at least a differential sense. That is, within any differentially small portion of the flat-panel light guide, the top and bottom surfaces are substantially parallel or coplanar.

In some embodiments, the plate light guide may be substantially flat (i.e., confined to a plane), and thus the plate light guide is a planar light guide. In other embodiments, the flat panel light guide may be curved in one or two orthogonal dimensions. For example, a flat-panel light guide may be bent in a single dimension to form a cylindrical flat-panel light guide. However, any curvature has a radius of curvature large enough to ensure that total internal reflection is maintained within the plate-type light guide to guide the light.

Herein, an "angle-preserving scattering feature" or equivalently "angle-preserving diffuser" is any feature or diffuser configured to scatter light in a manner that substantially preserves the angular spread (angular spread) of light incident on the feature or diffuser in the scattered light. More specifically, by definition, the angular spread σ s of light scattered by the angle preserving scattering feature is a function of the angular spread σ of the incident light (i.e., σ s ═ f (σ)). In some embodiments, the angular spread σ s of the scattered light is a linear function of the angular spread or collimation factor σ of the incident light (e.g., σ s ═ a · σ, where a is an integer). That is, the angular spread σ s of light scattered by the angle preserving scattering feature may be substantially proportional to the angular spread or collimation factor σ of the incident light. For example, the angular spread σ s of the scattered light may be substantially equal to the angular spread σ of the incident light (e.g., σ s ≈ σ). A uniform diffraction grating (i.e., a diffraction grating having a substantially uniform or constant diffraction feature pitch or grating pitch) is one example of an angle-preserving scattering feature. In contrast, Lambertian diffusers (Lambertian diffusers) or Lambertian reflectors (Lambertian reflectors) and general diffusers (e.g., with or near Lambertian scattering) are not angle-preserving diffusers, as defined herein.

As used herein, a "polarization-maintaining scattering feature" or equivalent "polarization-maintaining diffuser" is any feature or any diffuser configured to scatter light in a manner that substantially preserves the polarization or at least a degree of polarization of light incident on the feature or diffuser in the scattered light. Thus, a "polarization preserving scattering feature" is any feature or any scatterer in which the degree of polarization of light incident on the feature or scatterer is substantially equivalent to the degree of polarization of the scattered light. Further, by definition, "polarization preserving scattering" is a scattering (e.g., scattering of guided light) that preserves or substantially preserves a predetermined polarization of the scattered light. For example, the scattered light may be polarized light provided by a polarized light source.

Herein, a "diffraction grating" is generally defined as a plurality of features (i.e., diffractive features) arranged to provide diffraction of light incident on the diffraction grating. In some examples, the plurality of features may be arranged in a periodic or quasi-periodic manner. For example, a diffraction grating may include a plurality of features (e.g., a plurality of grooves or ridges in the surface of a material) arranged in a one-dimensional (1D) array. In other examples, the diffraction grating may be a two-dimensional (2D) array of features. For example, the diffraction grating may be a two-dimensional array of protrusions on or holes in the surface of the material.

As such, a "diffraction grating" is a structure that provides diffraction of light incident on the diffraction grating, according to the definitions herein. If light is incident on the diffraction grating from the light guide, the diffraction or diffractively scattering provided may result in and is therefore referred to as "diffractively coupled in" because the diffraction grating may couple light out of the light guide by diffraction. The diffraction grating also redirects or changes the angle of the light by diffraction (i.e., at diffraction angles). In particular, due to diffraction, light exiting a diffraction grating typically has a propagation direction that is different from the propagation direction of light incident on the diffraction grating (i.e., incident light). The change in the propagation direction of light by diffraction is referred to herein as "diffraction reorientation". A diffraction grating may thus be understood as a structure comprising diffractive features which redirect light incident on the diffraction grating via diffraction and which may also diffractively couple out light from the light guide if the light is emitted by the light guide.

Further, the features of a diffraction grating are referred to as "diffractive features" according to the definitions herein and may be one or more of at, in, and on the surface of a material (i.e., the boundary between two materials). For example, the surface may be a surface of a light guide. The diffractive features can include any of a variety of structures that diffract light, including, but not limited to, one or more of grooves, ridges, holes, and protrusions at, in, or on the surface. For example, the diffraction grating may comprise a plurality of substantially parallel grooves in the surface of the material. In another example, the diffraction grating may comprise a plurality of parallel ridges protruding from the surface of the material. The diffractive features (e.g., grooves, ridges, apertures, protrusions, etc.) can have any of a variety of cross-sectional shapes or profiles that provide diffraction, including but not limited to sinusoidal profiles, rectangular profiles (e.g., binary diffraction gratings), triangular profiles, and sawtooth profiles (e.g., blazed gratings).

According to various examples described herein, a diffraction grating (e.g., of a multibeam element as described below) may be employed to diffractively scatter or couple light out of a light guide (e.g., a flat-panel light guide) as a light beam. In particular, the diffraction angle θ of the locally periodic diffraction grating_mOr diffraction angle theta provided by a locally periodic diffraction grating_mCan be given by equation (1) as:

where λ is the wavelength of the light, m is the diffraction order, n is the refractive index of the light guide, d is the spacing or pitch between the features of the diffraction grating, and θ_iIs the angle of incidence of the light on the diffraction grating. For simplicity, equation (1) assumes that the diffraction grating is adjacent to a surface of the light guide and that the refractive index of the material outside the light guide is equal to 1 (i.e., n)_out1). Typically, the diffraction order m is given as an integer. Diffraction angle theta_mThe beam produced by the diffraction grating may have a diffraction order therein that is positive (e.g., m)>0) Equation (1) of (a). For example, first order diffraction is provided when the diffraction order m is equal to 1 (i.e., m is 1).

Figure 2 illustrates a cross-sectional view of a diffraction grating 30 in one example, according to an embodiment consistent with the principles described herein. For example, the diffraction grating 30 may be located on a surface of the light guide 40. In addition, FIG. 2 shows the angle of incidence θ_iAn incident beam 50 incident on the diffraction grating 30. Incident light beam 50 may be a guided light (i.e., a guided light beam) within light guide 40. Also shown in fig. 2 is that diffraction grating 30 diffractively generates and couples out directional beam 60 due to diffraction of incident beam 50. The directional beam 60 has a diffraction angle θ as shown in equation (1)_m(or, in this context, "principal angular direction"). Diffraction angle theta_mMay correspond to the diffraction order "m" of the diffraction grating 30, for example, the diffraction order m is 1 (i.e., the first diffraction order).

As defined herein, the term "multi-beam element" is a structure or element of a backlight or display that generates light that includes multiple beams. In some embodiments, the multi-beam element may be optically coupled to a light guide of the backlight panel to provide a plurality of light beams by coupling out or scattering out a portion of the light guided in the light guide. Further, the beams of the plurality of beams generated by the multibeam element have a plurality of principal angular directions that are different from each other, according to the definitions herein. In particular, by definition, a light beam of the plurality of light beams has a predetermined main angular direction different from another light beam of said plurality of light beams. Thus, a light beam is referred to as a "directional light beam" and a plurality of light beams may be referred to as a plurality of directional light beams, as defined herein.

Also, multiple directional beams may represent the light field. For example, the plurality of directional light beams may be confined in a substantially conical spatial area or have a predetermined angular spread comprising different principal angular directions of the light beams of the plurality of light beams. Thus, the combination of the predetermined angular spread of the light beams (i.e. the light beams) may represent the light field.

According to various embodiments, the different principal angular directions of the various directional beams of the plurality of directional beams may be determined according to characteristics, which may include, but are not limited to, dimensions (e.g., length, width, area, etc.) of the multibeam element. In some embodiments, the multibeam element may be considered an "extended point source," i.e., a plurality of point sources distributed within the multibeam element, as defined herein. Furthermore, the directional beams of light produced by the multibeam element have a predominant angular direction given by the angular component { θ, φ }, as defined herein, and as described above with respect to FIG. 1B.

In this context, a "collimator" is defined as essentially any optical element or device for collimating light. By way of example, the collimator may include, but is not limited to, a collimating mirror or reflector, a collimating lens, a diffraction grating, a tapered light guide, and combinations of the various collimators described above. According to various embodiments, an amount of collimation provided by the collimator may vary from one embodiment to another by a predetermined angle or amount. Further, the collimator may be used to provide collimation in one or both of two orthogonal directions (e.g., a vertical direction and a horizontal direction). In other words, according to some embodiments of the invention, the collimator may comprise a shape or similar collimating feature for providing one or both of the two orthogonal directions of light collimation.

Herein, the "collimation factor" is defined as the degree to which light is collimated. In more detail, the collimation factor defines the angular spread of the rays in the collimated beam. For example, the collimation factor σ may specify that a majority of rays in a beam of collimated light are within a particular angular spread (e.g., +/- σ degrees with respect to the center or principal angular direction of the collimated beam). According to some examples, the rays of the collimated light beam may have a Gaussian distribution (Gaussian distribution) in angle, and the angular spread may be an angle determined by half of the peak intensity of the collimated light beam.

A "light source" is defined herein as a source that emits light (e.g., an optical emitter to generate and emit light). For example, the light source may include an optical emitter, such as a Light Emitting Diode (LED), that emits light when activated or turned on. More specifically, the light source herein can be substantially any source of light or optical emitter including, but not limited to, one or more LEDs, lasers, Organic Light Emitting Diodes (OLEDs), polymer light emitting diode plasma optical emitters, fluorescent lamps, incandescent lamps, and any other source of visually observable light. The light generated by the light source may have a color (i.e., may include light of a particular wavelength), or may be a range of wavelengths (e.g., white light). In some embodiments, the light source may include a plurality of optical emitters. For example, the light source may include a group or cluster of optical emitters, wherein at least one optical emitter produces light having a color or equivalent a wavelength that is different from a color or wavelength of light produced by at least one other optical emitter of the group or cluster. The different colors may include, for example, primary colors (e.g., red, green, blue). A "polarized" light source is defined herein as essentially any light source that produces or provides light having a predetermined polarization. For example, the polarized light source may include a polarizer at the output of the optical emitter of the light source.

The term "accommodation" as used in this specification refers to a process of focusing on an object or an image element by changing the optical energy of the eye. In other words, accommodation refers to the ability of the eye to focus. Herein, "accommodation range" or equivalently "accommodation distance" is defined as the range of distances from the eye in which focusing can be achieved. While the adjustment range may vary from individual to individual, for example, for simplicity and not limitation, the minimum "normal" adjustment distance is set to be approximately equal to 25 centimeters. Thus, when an object is in the so-called "normal accommodation range", it is generally understood that the object is located more than 25 cm away from the eye.

Herein, the "eye box" refers to an area or space where a user can view an image formed by a display or other optical system (e.g., a lens system). In other words, the eye box defines the position in space where the user's eyes are suitably placed for viewing the image produced by the display system. In some embodiments, the eye box represents a two-dimensional spatial region (e.g., a region having a length and a width but no actual depth), while in other embodiments, the eye box may include a three-dimensional spatial region (e.g., a region having a length, a width, and a depth). Furthermore, when reference is made herein to a "box", the eye box is not limited to a rectangular area. For example, in some embodiments, the eye box may be a cylindrical spatial region.

In addition, as used herein, the articles "a" and "an" are intended to have their ordinary meaning in the patent arts, i.e., "one or more". For example, "multibeam element" means one or more multibeam elements, more specifically, "multibeam element" means "the multibeam element(s)" herein. Further, references herein to "top," "bottom," "upper," "lower," "upward," "downward," "front," "rear," "first," "second," "left," or "right" are not meant to be limiting. As used herein, the term "about" when applied to a value generally means within the tolerance of the equipment used to produce the value, or may mean plus or minus 10%, or plus or minus 5%, or plus or minus 1%, unless specifically stated otherwise. Further, the term "substantially" as used herein refers to an amount that is mostly, or almost entirely, or in the range of about 51% to about 100%. Moreover, the examples herein are merely illustrative and are for purposes of discussion and not limitation.

According to some embodiments consistent with principles described herein, the present invention provides a near-eye display. FIG. 3 illustrates a block diagram of a near-eye display 100 in an example, according to an embodiment consistent with the principles described herein. The near-eye display 100 is configured to provide a multi-view image in an eye box 102 of the near-eye display 100. More specifically, the near-eye display 100 may be used to provide a plurality of different views 104 of a multi-view image. Further, different views 104 may be provided at different locations within the eye box 102. According to various embodiments, different views 104 provided at different locations in the eye box 102 are configured to provide depth of focus cues (focus depth cuts) to a user of the near-eye display 100. For example, the depth of focus cues may enable a user to perceive the depth or distance of the multi-view image based on the depth of focus cues. The depth of focus cues provided to the user by the near-eye display 100 may include, but are not limited to, accommodation and retinal blur (retinitis blur).

As shown in fig. 3, the near-eye display 100 includes a multibeam element-based display 110. The multibeam element display 110 is used to provide a plurality of different views 104 of a multiview image. According to various embodiments, substantially any number of views may be provided as the different views 104. For example, the number of different views 104 of the multi-view image may include two, three, four, five, six, seven, eight, or more different views. In other examples, the plurality of different views 104 of the multi-view image includes a relatively large number of different views, which may include sixteen (16), thirty-two (32), sixty-four (64), one-hundred twenty-eight (128), or two-hundred fifty-six (256) different views, but the number of different views is not so limited. In some embodiments, the plurality of different views 104 includes at least four different views.

In some examples, the multi-view image provided or displayed by the near-eye display 100 includes only three-dimensional (3D) information or content (e.g., a 3D image representing a 3D object or scene). Thus, a multi-view image may be referred to as a "full" multi-view or 3D image. In other examples, the multi-view image may contain a portion that provides 3D content and a portion that includes two-dimensional (2D) information or content (e.g., a 2D image portion). When the multi-view image includes 3D content or an equivalent "3D image," the plurality of different visualizations 104 may represent different perspective views of the 3D image. In accordance with the principles described herein, the different views may enhance the user's perception of depth of field in the displayed image, for example, by way of one or both of accommodation or retinal blurring. In some examples (e.g., in binocular near-eye display systems, as described below), the accommodation function may mitigate effects caused by so-called accommodation-convergence differences that often occur in 3D images and particular 3D displays.

The near-eye display 100 shown in fig. 3 also includes an optical system 120. According to various embodiments, the optical system 120 is used to relay (relay) a multi-view image to the eye box 102 of the near-eye display 100. Specifically, according to various embodiments, the optical system 120 is used to relay the different views 104 of the multi-view image to corresponding different locations in the eye box 102. According to various embodiments, the process of forwarding different views 104 to different locations in the eye box 102 is used to provide depth of focus cues to a user of the near-eye display 100. For example, a first view of the multi-view image may be relayed by the optical system 120 to a first location, while a second view may be relayed by the optical system 120 to a second location in the eye box 102 separate from the first location. For example, the first and second locations may be laterally separated from one another. By the separation of the first view from the second view at the corresponding first and second positions, the user may be allowed to adjust differently in the multi-view image with respect to the two views at those positions.

According to some embodiments of the present invention, the full angular range of the plurality of different views 104 provided by the multibeam element-based display 110 at the input aperture of the optical system 120 is configured to correspond to the size of the input aperture. In particular, the combination of the multiple different views 104 subtends an angle configured such that no portion of the different views 104 is outside or beyond the input aperture. In other words, according to some embodiments of the present invention, almost all of the output beams of the multibeam element-based display 110 associated with different views 104 are configured to be received in the input aperture of the optical system 120. In some examples, the full angular extent (i.e., subtended angle) of the multiple different views 104 is configured to substantially correspond to the input aperture size in one or both of the following two ways: at a predetermined distance between the multibeam element based display 110 and the optical system input aperture, and at a predetermined angular spread of the different views 104 provided by the multibeam element based display 110.

According to some embodiments of the present invention, the optical system 120 comprises a magnifying lens. In some embodiments, the magnifying lens comprises a simple magnifying lens. The loupe is used to provide virtual images of the multi-view image at a distance from the eye box 102 that corresponds to a normal accommodation range of the user's eyes. Furthermore, according to various embodiments, the virtual image provided by the simple magnifier comprises the different views 104 of the multi-view image. In other embodiments, the magnifier may be a complex magnifier (e.g., multiple lenses for providing a magnifying function).

The term "simple magnifier" is defined herein as a lens or similar optical device capable of forming a magnified virtual image of a small object or image (i.e., a simple magnifier capable of providing angular magnification). The virtual image formed by the simple magnifier may be formed at the output of the simple magnifier, an equivalent output aperture, or an aperture of the simple magnifier (e.g., at eye box 102).

Further, the simple magnifier may form a magnified virtual image at a viewing distance (apparent distance) or virtual distance that is greater than the actual distance of the object, as defined herein. Thus, the loupe may be used to provide the user or "viewer" with the ability to focus on an object when the distance between the location of the object and the user's eye is less than the normal adjustment range or distance. In accordance with some embodiments of the invention, "normal accommodation" may generally be achieved at distances greater than twenty-five centimeters (25 centimeters) from the user's eyes, and thus is defined herein as such. Thus, while the distance between the multibeam element-based display 110 and the user's eye (i.e., or equivalently the eye movement range 102 of the near-eye display 100) providing the multi-view image is less than the normal accommodation distance (i.e., less than 25 centimeters), the simple magnifier of the optical system 120 may allow the user to comfortably view multiple different views 104 of the focused multi-view image (i.e., the "object").

Fig. 4 illustrates a schematic diagram of the optical elements of a near-eye display 100 in an example, according to an embodiment consistent with the principles described herein. As shown, the optical system 120 includes a simple magnifier 122 having a focal length f. By way of example and not limitation, the simple magnifier 122 of FIG. 4 is depicted as a lenticular lens. The distance between the position of the magnifying glass 122 and the eye box 102 may correspond to the focal length f of the magnifying glass 122 (e.g., as shown in fig. 4). Further, the magnifying glass 122 is located between the multibeam-element based display 110 and the eye box 102. The magnifier 122 is used to provide a virtual image 106 of a multi-view image formed by a plurality of different views (e.g., different views 104 in fig. 3) of the multi-beam element based display 110 (i.e., views when viewed through the magnifier 122 in the eye box 102). Since the magnification effect is provided by the simple magnifier 122, the distance between the virtual image 106 and the eye box 102 is greater (or at least appears to be greater) than the actual distance between the real image (i.e., the display image) produced by the multibeam element-based display 110 and the eye box 102. Specifically, according to some embodiments, the virtual image 106 may be located within a normal accommodation range or distance d of the human eye when viewed from the eye box 102_aAnd the distance between the multibeam element-based display 110 (or equivalently, the image produced or displayed by the multibeam diffraction element-based display 110) and the eye box 102 may be less than the normal accommodation range. Thus, for example, the magnifying glass 122 may facilitate a more comfortable viewing of the multibeam element based display 110 (or, equivalently, the output or virtual image 106 of the multibeam diffractive element based display 110) by a user in the eye box 102.

As described below, light rays 108 emanating from the multibeam element-based display 110 are further shown in solid and dashed lines in FIG. 4. The solid lines represent actual light rays 108 associated with different views 104 of the multi-view image provided by the multi-beam element based display 110, while the dashed lines represent projections of light rays corresponding to the virtual image 106. For example, as described below, the light rays 108 shown in FIG. 4 may correspond to various directional light beams (i.e., light rays) generated by a multibeam element-based display 110. Further, as shown, the light rays 108 converging at different points in the eye box 102 represent different views of the multi-view image provided by the multi-beam element based display 110 after being relayed to different locations in the eye box 102.

According to some embodiments of the present invention, the multibeam element based display 110 and the optical system 120 are positioned in a Field-of-view (FOV) of a user and substantially block a portion of the user's FOV. In these embodiments, the near-eye display 100 may be a virtual reality display. In particular, the near-eye display 100 may be configured to display an image with the near-eye in the blocked portion of the field of view to replace, or at least substantially replace, a view of the physical environment (i.e., a view of the real world). In other words, the near-eye display image may substantially replace the physical environment view in the blocked partial field of view. According to various embodiments, the portion of the field of view that is blocked may include some of the user's field of view or all of the user's field of view. By replacing the physical environment scene, the user may get a virtual reality view (and associated multiple views) provided by the near-eye display image instead of the physical environment view.

As used herein, a "view of the physical environment" or "view of the physical environment" is defined as the view that a user would see without the near-eye display 100. Similarly, by definition in this specification, a physical environment is meant all what a user can see outside of the near-eye display 100, and a physical environment "view" is meant to refer to anything that is in the user's field of view, but not to include any effect that the near-eye display 100 has on the user's scene.

In other embodiments, the multibeam element-based display 110 is positioned outside the field of view of the user, and the optical system 120 or a portion of the optical system 120 is positioned in the field of view. In these embodiments, the near-eye display 100 may be an augmented reality display. In particular, the near-eye display 100 may be used to display an image (and associated multiple different views 104) through the near-eye to enhance a view of the physical environment. Further, as an augmented reality display, the near-eye display 100 is configured to provide an overlay or combination of a near-eye display image and a physical environment scene other than the near-eye display 100 as a view to a user.

In some embodiments, the optical system 120 of the near-eye display 100 is configured as an augmented reality display having a freeform prism (freeform prism). The freeform prism is used to transfer the multi-view image including the different views 104 from the multi-beam based display 110 to the eye box 102 for viewing by the user. In addition, the freeform prism is used to relay the multi-view image of the multibeam element-based display 110 that is outside or outside the field of view of the user. According to various embodiments, the freeform prism utilizes total internal reflection between two surfaces (e.g., a front surface and a back surface) of the freeform prism to relay the multi-view image. In some embodiments, the freeform prism is or may act as a simple magnifier (e.g., simple magnifier 122).

In some embodiments, the optical system 120 configured as an augmented reality display further comprises a free-form surface compensation lens. The free form surface compensation lens may also be referred to as a free form surface corrector. Specifically, the free-form surface compensation lens is used to compensate or correct for the effect of the free-form surface lens on light passing through the optical system 120 from a physical environment other than the optical system 120 to the eye box 102. That is, according to various embodiments, the freeform compensation lens allows a user to receive a complete scene of the physical environment (i.e., in the user's field of view) without being affected by significant distortion caused by the freeform prism.

FIG. 5 illustrates a cross-sectional view of an exemplary near-eye display 100 having an optical system 120 that includes a freeform prism 124, according to an embodiment consistent with the principles described herein. As shown in fig. 5, the free-form surface prism 124 of the optical system 120 is positioned between the multibeam element display 110 and the eye box 102 (i.e., exit pupil) of the near-eye display 100. Light representing the multi-view image including the different views 104 provided by the multi-beam element based display 110 is relayed from its input aperture to the eye box 102 by the freeform prism 124. In FIG. 5, the light system from the multibeam element display 110 is shown as light 108. According to various embodiments, the process of forwarding the light rays 108 from the input to the output of the freeform prism 124 may be provided by total internal reflection within the freeform prism 124.

The field of view of the user is also shown in fig. 5. The virtual image 106 is positioned in the field of view to provide a superposition of the virtual image 106 and the scene of the physical environment in the field of view. In addition, as shown in FIG. 5, the multibeam element-based display 110 is located outside of the field of view. Thus, as an example of the present invention, an embodiment of an augmented reality display of a near-eye display 100 is shown in FIG. 5.

The optical system 120 shown in fig. 5 also includes a free-form surface compensation lens 126. According to various embodiments, the freeform compensation lens 126 may be disposed in an optical path between a physical environment (e.g., a physical environment for viewing by a user) and the eye box 102. Specifically, as shown in the figure, the freeform compensation lens 126 is adjacent to the freeform prism 124 and is located between the physical environment and the freeform prism 124. The freeform compensation lens 126 is used to correct the effects of the freeform prism 124 so that light rays (not shown) from objects in the physical environment pass through to the eye box 102 according to a substantially straight path (i.e., the light rays are substantially undistorted). In some embodiments (as shown), a partial reflector or partially reflective surface 128 may be disposed between the freeform compensation lens 126 and the freeform prism 124. The partially reflective surface 128 is for reflecting light incident on the partially reflective surface 128 from the freeform prism 124 and is configured to allow light from the physical environment to pass through the partially reflective surface 128.

Referring again to fig. 3, in some embodiments, the multibeam element-based display 110 includes a light guide for guiding a collimated light beam at a non-zero conduction angle. In some embodiments, the multibeam element display 110 further comprises an array of multibeam elements located at or adjacent to the surface of the light guide. According to various embodiments, the array of multibeam elements is for diffractively coupling out a portion of the guided collimated light beam into a plurality of coupled-out light beams having different principal angular directions, wherein the different principal angular directions correspond to different view directions of different views 104 of the multi-view image.

According to various embodiments, the multibeam element based display 110 of the near-eye display 100 includes an array of multibeam elements. The array of multibeam elements is configured to provide a plurality of directional light beams having directions corresponding to various view directions of a plurality of different views of the multi-view image. According to various embodiments, the multibeam element based display 110 of the near-eye display 100 further comprises a light valve array to condition the plurality of directional light beams to provide the multi-view image.

FIG. 6A illustrates a cross-sectional view of a multibeam element-based display 110 in an example, according to an embodiment consistent with the principles described herein. Fig. 6B illustrates a plan view of a multibeam element-based display 110 in an example, according to an embodiment consistent with the principles described herein. Fig. 6C illustrates a perspective view of an exemplary multibeam element-based display 110, according to an embodiment consistent with the principles described herein. The perspective view in fig. 6C is shown partially cut away to facilitate discussion herein only.

The multibeam element-based display 110 illustrated in fig. 6A-6C is to provide a plurality of directional light beams 111 (e.g., to become a light field) having different principal angular directions from each other. Specifically, according to various embodiments, the plurality of directional light beams 111 are provided away from the multibeam element-based display 110 in different principal angular directions corresponding to various view directions of the plurality of different views 104. Further, the directional beam 111 is modulated (e.g., using a light valve, as described below) to provide or display a multi-view image. In some embodiments, the multi-view image may include 3D content (e.g., virtual objects are represented in different perspective views that would render the 3D object when viewed by the user).

As shown in fig. 6A-6C, the multibeam element-based display 110 includes a light guide 112. According to some embodiments, the light guide 112 may be a flat plate light guide. The light guide 112 is configured to guide light along a length of the light guide 112 as guided light 113. For example, the light guide 112 may include a dielectric material configured as an optical waveguide. The dielectric material may have a first refractive index that is greater than a second refractive index of a medium of the optical waveguide surrounding the dielectric. For example, the difference in refractive index is configured to contribute to total internal reflection of the guided light 113 according to one or more guiding modes of the light guide 112.

In particular, the light guide 112 may be a slab or slab optical waveguide that includes an extended, substantially flat sheet of optically transparent dielectric material. The generally planar sheet of dielectric material guides the guided light 113 by total internal reflection. According to various examples, the optically transparent material in the light guide 112 can include any of a variety of dielectric materials, which can include, but are not limited to, one or more of various forms of glass (e.g., quartz glass, alkali-aluminosilicate glass, borosilicate glass, etc.) and substantially optically transparent plastics or polymers (e.g., poly (methyl methacrylate) or "acrylic glass", polycarbonate, etc.). In some examples, the light guide 112 can also include a cladding layer (not shown) on at least a portion of a surface (e.g., one or both of the top and bottom surfaces) of the light guide 112. According to some examples, cladding layers may be used to further contribute to total internal reflection.

Further, according to some embodiments, the light guide 112 is configured to guide the guided light 113 according to total internal reflection between a first surface 112' (e.g., a "front" surface or side) and a second surface 112 "(e.g., a" back "surface or side) of the light guide 112 over a non-zero conduction angle. Specifically, the guided light 113 is guided by reflecting or "bouncing" between the first surface 112' and the second surface 112 "of the light guide 112 at a non-zero conduction angle. In some embodiments, the directed light 113 includes a plurality of directed light beams of different light colors. Light beams of the plurality of guided light beams may be guided by the light guide 112 at respective ones of the different color-specific, non-zero conduction angles. It should be noted that the non-zero conduction angles are not shown for simplicity of illustration. However, the thick arrows depicting the conduction direction 115 show the overall conduction direction of the guided light 113, which is along the length of the light guide in fig. 6A.

As defined herein, a "non-zero conduction angle" is an angle relative to a surface (e.g., the first surface 112' or the second surface 112 ") of the light guide 112. Further, according to various embodiments, the non-zero value conduction angles are each greater than zero and less than the critical angle for total internal reflection within the light guide 112. For example, the non-zero conduction angle of the guided light 113 may be between about ten (10) degrees and about fifty (50) degrees, or in some examples, between about twenty (20) degrees and about forty (40) degrees, or between about twenty-five (25) degrees and about thirty-five (35) degrees. For example, the non-zero conduction angle may be approximately thirty (30) degrees. In other examples, the non-zero value conduction angle may be about 20 degrees, or about 25 degrees, or about 35 degrees. Furthermore, for particular implementations, a particular non-zero conduction angle may be selected (e.g., any) as long as the particular non-zero conduction angle is selected to be less than the critical angle for total internal reflection within the light guide 112.

Guided light 113 in the light guide 112 may be introduced or coupled into the light guide 112 at a non-zero conduction angle (e.g., about 30-35 degrees). For example, one or more lenses, mirrors, or similar reflectors (e.g., a tilted collimating reflector), diffraction gratings, and prisms (not shown) may cause light to be coupled into the input of the light guide 112 at non-zero conduction angles to become guided light 113. Once coupled into the light guide 112, the guided light 113 is guided along the light guide 112 in a direction that may be generally away from the input end (e.g., shown in fig. 6A with a bold arrow pointing toward the x-axis).

Further, according to various embodiments, the guided light 113, or equivalently the guided light beam 113, produced by coupling light into the light guide 112 may be a collimated light beam. In the present disclosure, "collimated light" or "collimated light beam" is generally defined as a beam of light in which several beams of light are substantially parallel to each other within the beam (e.g., within the guided light 113). Further, light rays that diverge or scatter from the collimated beam are not considered part of the collimated beam, as defined herein. In some embodiments, the multibeam element display 110 may include a collimator, such as, but not limited to, a lens, reflector or mirror, a diffraction grating, or a tapered light guide, to collimate light, such as to collimate light from a light source. In some embodiments, the light source comprises a collimator. The collimated light provided to the light guide 112 is collimated guided light 113. In various embodiments, the guided light 113 may be collimated according to a collimation factor σ, or the guided light 113 may have both a collimation factor σ.

In some embodiments, the light guide 112 may be used to "recycle" the guided light 113. In particular, guided light 113 guided along the length of the light guide may be redirected back along another conduction direction 115' different from the conduction direction 115. For example, the light guide 112 may include a reflector (not shown) at an end of the light guide 112 opposite the input end adjacent the light source. The reflector may be used to reflect the guided light 113 back into the input as recycled guided light. Recycling the guided light 113 in this manner increases the brightness (e.g., the intensity of the directional beam 111) of the multibeam element-based display 110 by allowing the guided light to be provided more than once, e.g., to the multibeam element, as described below.

In fig. 6A, a thick arrow (e.g., pointing in the negative x-direction) showing the direction of propagation 115' of the recycled guided light shows the general direction of propagation of the recycled guided light within the light guide 112. Alternatively (e.g. as opposed to recycling guided light), guided light 113 guided in another direction of propagation 115 'may be provided by introducing light into the light guide 112 in another direction of propagation 115' (e.g. in addition to guided light 113 having a direction of propagation 115).

As shown in fig. 6A-6C, the multibeam element based display 110 further includes a plurality of multibeam elements 114 or an array of multibeam elements 114 spaced apart from each other along the length of the light guide 110. In particular, the multibeam elements 114 in the array of multibeam elements 114 (or array of multibeam elements) are separated from each other by a finite space and represent separate, distinct elements along the length of the light guide. Thus, the multibeam elements 114 in the multibeam element array are spaced apart from one another according to a finite (i.e., non-zero value) inter-element distance (e.g., a finite center-to-center distance), as defined herein. Further, the multibeam elements 114 in the array of multibeam elements generally do not intersect, overlap, or contact each other, according to some embodiments. Thus, each multi-beam element 114 in the array of multi-beam elements is generally distinct and separate from other multi-beam elements 114 in the plurality of multi-beam elements 114.

According to some embodiments, the multibeam elements 114 of the multibeam element array may be arranged in a one-dimensional (1D) array or a two-dimensional (2D) array. For example, the array of multibeam elements 114 may be arranged in a linear 1D array. In another example, the array of multibeam elements 114 may be arranged in a rectangular 2D array or a circular 2D array. Further, in some examples, the array (i.e., 1D or 2D array) may be a conventional or unified array. In particular, the inter-element distance (e.g., center-to-center distance or pitch) between the plurality of multibeam elements 114 may be substantially uniform or constant across the array. In other examples, the inter-element distance between the plurality of multibeam elements 114 may vary to one or both of across the array and along the length of the light guide 112.

According to various embodiments, the multibeam elements 114 in the multibeam element array are to couple or scatter a portion of the guided light 113 into the plurality of directional light beams 111. Specifically, fig. 6A and 6C depict the directional light beam 111 as a plurality of diverging arrows, depicted as being directed away from a first surface (or front surface) 112' of the light guide 112. Further, according to various embodiments, the size of the multibeam element 114 is comparable to (compatible) the size of the view pixels (or equivalently, the size of the light valves 116 as described below) in the multiview pixels of the multibeam element based display 110.

As used herein, the "dimension" may be defined in any of a variety of ways including, but not limited to, length, width, or area. For example, the size of a view pixel may be its length, and a comparable size of the multibeam element 114 may also be the length of the multibeam element 114. In another example, the dimensions may refer to areas such that the area of the multibeam element 114 may be comparable to the area of the view pixel.

In some embodiments, the size of the multibeam element 114 may be comparable to the size of a view pixel, and the size of the multibeam element is between fifty percent (50%) to two hundred percent (200%) of the size of the view pixel. For example, if the dimension of the multibeam element is denoted as "S" and the dimension of the view pixel is denoted as "S" (as shown in fig. 6A), the dimension of the multibeam element S can be given by equation (2), equation (2) being:

in other examples, the size of the multibeam element is greater than about sixty percent (60%), or about seventy percent (70%), or greater than about eighty percent (80%), or greater than about ninety percent (90%) of the size of the view pixel, and the multibeam element is less than about one hundred eighty percent (180%), or less than about one hundred sixty percent (160%), or less than about one hundred forty percent (140%), or less than about one hundred twenty percent (114%) of the size of the view pixel. For example, with "comparable dimensions," the dimensions of the multibeam element may be between about seventy-five percent (75%) and about one-hundred fifty percent (150%) of the dimensions of the view pixel. In another example, the multibeam element 114 may be comparable in size to a view pixel, where the size of the multibeam element is between approximately one hundred twenty five percent (125%) to eighty five percent (85%) of the size of the view pixel. According to some embodiments, the comparable sizes of the multibeam element 114 and the view pixels (or light valves 116) may be selected with the goal of reducing, or in some examples minimizing, dark regions between views of the multiview image, while at the same time, the overlap between different views of the multiview display may be reduced, or in some examples minimized.

As shown in fig. 6A-6C, the multibeam element-based display 110 further includes an array of light valves 116 (or an array of light valves). The array of light valves 116 is used to modulate the directional beam 111 of the plurality of directional beams. Specifically, the light valve array may be used to adjust the directional light beams 111 into an image, such as a multi-view image, displayed by the multibeam-element display 110. In fig. 6C, the array of light valves 116 is partially cut away to allow visualization of the light guide 112 and the multibeam element 114 below the light valve array.

Different ones of the directional light beams 111 having different principal angular directions are configured to pass through different light valves 116 in the array of light valves and thus be modulated by the different light valves 116. Further, as shown, the pairs of light valves 116 in the array correspond to view pixels, and a group of light valves 116 in the array of light valves correspond to multi-view pixels of the multibeam element-based display 110. Specifically, a different set of light valves 116 in the light valve array is configured to receive and modulate the directional beams 111 from different ones of the plurality of multibeam elements 114. Thus, as shown, each multibeam element 114 has a unique set of light valves 116. In various embodiments, any of a variety of light valves may be used as the plurality of light valves 116 of the light valve array, including, but not limited to, one or more of a plurality of liquid crystal light valves, a plurality of electrophoretic light valves, and a plurality of light valves based on or using electrowetting.

As shown, FIG. 6A shows a first set of valves 116-1 configured to receive and condition directional beams 111 from a first multibeam element 114-1, while a second set of valves 116-2 is configured to receive and condition directional beams 111 from a second multibeam element 114-2. Thus, as shown in fig. 6A, each of a plurality of valve sets in the valve array (e.g., the first valve set 116-1 and the second valve set 116-2) respectively corresponds to a different multiview pixel, wherein an individual valve 116 of the plurality of valve sets corresponds to a view pixel of the corresponding multiview pixel.

It should be noted that in fig. 6A, the size of the view pixels may correspond to the actual size of the light valves 116 in the light valve array. In other examples, the size of a view pixel or an equivalent light valve size may be defined as a distance (e.g., a center-to-center distance) between adjacent light valves 116 in the light valve array. For example, the light valves 116 may be smaller than a center-to-center distance between a plurality of light valves 116 in the light valve array. For example, the size of the view pixel or the light valve size may be defined as the size of the light valve 116 or a size corresponding to a center-to-center distance between the plurality of light valves 116.

In some embodiments, the relationship between the multibeam elements 114 in the multibeam element array and the corresponding multiview pixels (e.g., the complex array light valve 116) may be a one-to-one relationship. That is, there may be the same number of multiview pixels and multibeam elements 114. Fig. 6B explicitly shows, by way of example, a one-to-one relationship, wherein each multi-view pixel, including a different set of light valves 116, is depicted surrounded by a dashed line. In other embodiments (not shown), the number of multiview pixels and the number of multiple beam elements 114 may be different from each other.

In some embodiments, an inter-element distance (e.g., center-to-center distance) between adjacent pairs of the multibeam elements 114 in the multibeam element array may be equal to an inter-pixel distance (e.g., center-to-center distance) between adjacent pairs of the multiview pixels in the corresponding plurality of multiview pixels, e.g., represented by a plurality of groups of light valves. For example, as shown, in fig. 6A-6B, the center-to-center distance D between the first and second multibeam elements 114-1 and 114-2 is substantially equal to the center-to-center distance D between the first and second valve sets 116-1 and 116-2. In another embodiment (not shown), the relative center-to-center distances of the pair of multibeam elements 114 and the corresponding sets of valve groups may be different, e.g., the multibeam element 114 may have an inter-element spacing (i.e., center-to-center distance D) that is greater or less than a spacing (e.g., center-to-center distance D) between the sets of valve groups representing the multiview pixel.

In some embodiments, the shape of the multibeam element 114 may be similar to the shape of a multiview pixel, or equivalently, the shape of a set of light valves 116 (or "sub-array") corresponding to a multiview pixel. For example, the multibeam element 114 may have a square shape, and the multiview pixel (or corresponding set of arrangements of light valves 116) may be substantially square. In another example, the multibeam element 114 may have a rectangular shape, i.e., may have a length or longitudinal dimension that is greater than a width or transverse dimension. In this example, the multiview pixels (or an arrangement equivalent to the complex array of light valves 116) corresponding to the multibeam element 114 may have a rectangular-like shape. Figure 6B shows a top or plan view of a square multibeam element 114 and a corresponding square multiview pixel that includes a square complex array of light valves 116. In still other examples (not shown), the multibeam element 114 and the corresponding multiview pixel have various shapes, including or at least approximate, but not limited to, triangular, hexagonal, and circular.

Further (e.g., as shown in fig. 6A), according to some embodiments, each multibeam element 114 is to provide a directional light beam 111 to one and only one multiview pixel. In particular, for a given one of the multibeam elements 114, the directional light beams 111 having different principal angular directions corresponding to different views 104 of the multiview image are substantially limited to a single corresponding multiview pixel and its view pixel, i.e., a single set of light valves 116 corresponding to the multibeam element 114 (e.g., as shown in fig. 6A). Thus, each multibeam element 114 of the multibeam element based display 110 provides a corresponding set of directional light beams 111 having a set of different principal angular directions corresponding to different views 104 of the multiview image (i.e., the set of directional light beams 111 includes light beams having a direction corresponding to each of the different view directions).

According to various embodiments, the multibeam element 114 may include any one of a number of different structures to couple out a portion of the guided light 113. By way of example, the different structures may include, but are not limited to, diffraction gratings, micro-reflective elements, micro-refractive elements, or various combinations thereof. In some embodiments, the multibeam element 114 includes a diffraction grating to diffractively couple out a portion of the guided light into a plurality of directional light beams 111 having different principal angular directions. In other embodiments, the multibeam element 114 comprises a micro-reflective element to reflectively couple out a portion of the guided light into the plurality of directional beams 111, or the multibeam element 114 comprises a micro-refractive element to couple out a portion of the guided light into the plurality of directional beams 111 (i.e., refractively couple out a portion of the guided light) by or with refraction.

Fig. 7A illustrates a cross-sectional view of a portion of a multibeam element-based display 110 including a multibeam element 114 in an example, according to an embodiment consistent with principles described herein. FIG. 7B illustrates a cross-sectional view of a portion of a multibeam element-based display 110 including a multibeam element 114 in one example, according to an embodiment consistent with the principles described herein. Specifically, fig. 7A-7B illustrate the multibeam element 114 of the multibeam element based display 110 including the diffraction grating 114 a. The diffraction grating 114a is configured to diffractively couple a portion of the guided light 113 into a plurality of directional light beams 111. The diffraction grating 114a includes a plurality of diffractive features spaced apart from one another by a diffractive feature pitch, or diffractive feature, or grating pitch, that serves to provide the diffractively coupled-out portion of the guided light. According to various embodiments, the pitch of the diffractive features in the diffraction grating 114a, or the grating pitch, may be a sub-wavelength (i.e., less than the wavelength of the guided light).

In some embodiments, the diffraction grating 114a of the multibeam element 114 may be located at a surface of the light guide 112, or may be adjacent to a surface of the light guide 112. For example, the diffraction grating 114a may be located at the first surface 112 'of the light guide 112 or near the first surface 112' of the light guide 112, as shown in FIG. 7A. The diffraction grating 114a at the first surface 112 'of the light guide may be a transmission mode diffraction grating to diffractively couple a portion of the guided light through the first surface 112' into the directional beam 111. In another example, as shown in fig. 7B, the diffraction grating 114a may be located at or near the second surface 112 "of the light guide 112. When located on the second surface 112 ", the diffraction grating 114a may be a reflection mode diffraction grating. As a reflection mode diffraction grating, the diffraction grating 114a is to diffract part of the guided light and reflect part of the guided light toward the first surface 112 'to exit the directional light beam 111 as a diffraction through the first surface 112'. In other embodiments (not shown), the diffraction grating may be located between surfaces of the light guide 112, for example as one or both of a transmission mode diffraction grating and a reflection mode diffraction grating. It should be noted that in some embodiments described herein, the primary angular direction of the directional light beam 111 may include a refraction effect resulting from the directional light beam 111 exiting the light guide 112 at the light guide surface. By way of example, and not limitation, fig. 7B illustrates refraction (i.e., bending) of directional beam 111 due to a change in refractive index as directional beam 111 passes through first surface 112'. See also fig. 10A and 10B, as described below.

According to some embodiments, the diffractive features of the diffraction grating 114a may include one or both of grooves and ridges that are spaced apart from one another. The grooves or ridges may comprise the material of the light guide 112, e.g. may be formed in a surface of the light guide 112. In another example, the grooves or ridges may be formed of a material other than the light-guiding material, such as a film or layer of another material on the surface of the light guide 112.

In some embodiments, the diffraction grating 114a of the multibeam element 114 is a uniform diffraction grating, wherein the diffractive feature pitch is substantially constant or invariant throughout the diffraction grating 114 a. In other embodiments, the diffraction grating 114a may be a chirped (chirped) diffraction grating. By definition, a "chirped" diffraction grating is a diffraction grating that exhibits or has a diffraction spacing (i.e., a shutter pitch) of diffractive features that varies over the range or length of the chirped diffraction grating. In some embodiments, a chirped diffraction grating may have or exhibit a "chirp" or variation of the diffractive feature spacing that varies linearly with distance. Thus, by definition, a chirped diffraction grating is a "linearly chirped" diffraction grating. In other embodiments, the chirped diffraction grating of the multibeam element 114 may exhibit a non-linear chirp of the diffractive feature pitch. Various non-linear chirps may be used, including but not limited to exponential chirps, logarithmic chirps, or chirps that vary in a substantially non-uniform or random but still monotonic manner. Non-monotonic chirps may also be used, such as but not limited to sinusoidal chirps, or triangular, or saw tooth chirps. Combinations of any of these types of chirps may also be used.

In some embodiments, the diffraction grating 114a may include multiple diffraction gratings or an equivalent plurality of sub-gratings. Figure 6A illustrates a cross-sectional view of a diffraction grating 114a including a plurality of sub-gratings in one example, according to an embodiment consistent with the principles described herein. FIG. 8B illustrates a plan view of the diffraction grating 114a of FIG. 6A in an example, according to an embodiment consistent with the principles described herein; the cross-sectional view in fig. 6A may represent a cross-section taken, for example, from left to right from the bottom column of sub-gratings of the diffraction grating 114a shown in fig. 8B. As shown in fig. 6A and 8B, the plurality of sub-gratings includes a first sub-grating 114a-1 and a second sub-grating 114a-2 within a diffraction grating 114a of the multibeam element 114 on a surface of the light guide 112 (e.g., the second surface 112 as shown). The size s of the multibeam element 114 is shown in fig. 6A and 8B, and the boundaries of the multibeam element 114 are shown with dotted lines in fig. 8B.

According to some embodiments, the differential density of sub-gratings within the diffraction grating 114a between different multibeam elements 114 in the plurality of multibeam cells may be used to control the relative intensities of the plurality of directional light beams 111 diffractively scattered by the respective different multibeam elements 114. In other words, the diffractive multibeam element 114 may have the diffraction grating 114a therein in different densities, and the different densities (i.e., the different densities of the sub-gratings) may be used to control the relative intensities of the plurality of directional beams 111. Specifically, in the diffraction grating 114a, the multibeam element 114 having fewer sub-gratings may generate the plurality of directional beams 111 having a lower intensity (or beam density) than another multibeam element 114 having relatively more sub-gratings. For example, the position in the multibeam element 114 may be utilized to provide a differential density of sub-gratings, such as the position 114 a' shown in FIG. 8B where a sub-grating is absent or not disposed.

Fig. 9 illustrates a plan view of a pair of multibeam elements 114 in an example, according to an embodiment consistent with the principles described herein. As shown, a first multibeam element 114-1 of the pair of multibeam elements 114 has a higher density of sub-gratings within the diffraction grating 114a than is present in a second multibeam element 114-2 of the pair of multibeam elements 114. Specifically, the second multibeam element 114-2 has a diffraction grating 114a with fewer sub-gratings and more locations 114 a' without sub-gratings than the first multibeam element 114-1. In some embodiments, a higher density of sub-gratings in the first multibeam element 114-1 may provide a plurality of directional beams having a higher intensity than the intensity of the plurality of directional beams provided by the second multibeam element 114-2. According to some embodiments, the higher and lower intensities of the respective plurality of directional light beams provided by the differential sub-grating density shown in fig. 9 may be used to compensate for the light intensity of the guided light, which varies with the travel distance within the light guide. By way of example and not limitation, FIG. 9 also shows a diffraction grating 114a having sub-gratings with curved diffractive features.

Fig. 10A illustrates a cross-sectional view of a portion of a multi-beam display 110 including, in an example, a multi-beam element 114, according to another embodiment consistent with principles described herein. Fig. 10B illustrates a cross-sectional view of a portion of a multibeam element-based display 110 including a multibeam element 114 in an example, according to an embodiment consistent with the principles described herein. In particular, fig. 10A and 10B illustrate various embodiments of the multibeam element 114 including micro-reflective elements. The plurality of micro-reflective elements used as or in the multi-beam element 114 may include, but are not limited to, reflectors (e.g., reflective metals) using a reflective material or film thereof or reflectors based on Total Internal Reflection (TIR). According to some embodiments (e.g., as shown in fig. 10A-10B), the multibeam element 114 comprising the micro-reflective elements may be located at a surface (e.g., the second surface 112 ") of the light guide 112 or in the vicinity of the light guide 112. In other embodiments (not shown), the micro-reflective elements may be located in the light guide 112 at a position between the first surface 112 and the second surface 112.

For example, fig. 10A illustrates a multibeam element 114 that includes a micro-reflective element 114b, the micro-reflective element 114b having a reflective multi-faceted structure (facets) (e.g., a "prismatic" micro-reflective element) positioned proximate to the second surface 112 "of the light guide 112. The faceted structure of prismatic micro-reflective elements 114b serves to reflect (i.e., reflectively scatter) a portion of the guided light 113 out of light guide 112 as a directional light beam 111. For example, the faceted structure may be tilted or skewed (i.e., have a tilt angle) relative to the direction of propagation of the guided light 113 to reflect a portion of the guided light out of the light guide 112. According to various embodiments, the multi-faceted structure may be formed using a reflective material within the light guide 112 (e.g., as shown in fig. 10A), or may be multiple surfaces of a prismatic cavity in the second surface 112 ″. In some embodiments, when prismatic cavities are employed, the refractive index variation at the cavity surface may provide reflection (e.g., TIR reflection), or the cavity surfaces forming the multi-faceted structure may be coated with a reflective material to provide reflection.

In another example, fig. 10B illustrates a multibeam element 114 that includes a micro-reflective element 114B, the micro-reflective element 114B having a substantially smooth curved surface, such as, but not limited to, a hemispherical micro-reflective element 114B. For example, a particular surface curve of the micro-reflective element 114b may be used to reflect portions of the guided light in different directions, depending on the point of incidence on the curved surface that is in contact with the guided light 113. As shown in fig. 10A and 10B, by way of example and not limitation, the portion of the guided light that is reflectively scattered from the light guide 112 is emitted or exited from the first surface 112'. Like the prismatic micro-reflective elements 114B in fig. 10A, the micro-reflective elements 114B in fig. 10B may be reflective material within the light guide 112 or a cavity (e.g., a semi-circular cavity) formed in the second surface 112 ", as shown by way of example and not limitation in fig. 10B. By way of example and not limitation, fig. 10A and 10B also illustrate guided light 113 having two directions of propagation 115, 115' (i.e., illustrated by the bold arrows). For example, the use of two propagation directions 115, 115' may help to provide a main angular direction of symmetry for the plurality of directional beams 111.

Fig. 11 illustrates a cross-sectional view of a portion of a multi-beam display 110 including, in one example, a multi-beam element 114, according to another embodiment consistent with the principles described herein. Specifically, fig. 11 shows the multibeam element 114 including the micro-refractive element 114 c. According to various embodiments, the micro-refractive element 114c is to refractively couple out or scatter out a portion of the guided light 113 from the light guide 112. That is, as shown in fig. 11, the micro-refractive element 114c is configured to use refraction (e.g., refractive coupling as opposed to diffraction or reflection) to couple or scatter a portion of the guided light from the light guide 112 into the directional beam 111. Micro-refractive element 114c may have various shapes including, but not limited to, a hemispherical shape, a rectangular shape, a prismatic shape (i.e., a multi-faceted structure having a slope), and an inverted prismatic shape (e.g., as shown in fig. 11). According to various embodiments, the micro-refractive element 114c may extend or protrude from a surface (e.g., the first surface 112') of the light guide 112, as shown, or may be a cavity in the surface (not shown). Further, in some embodiments, the micro-refractive element 114c may comprise the material of the light guide 112. In other embodiments, the micro-refractive element 114c may comprise another material adjacent to the light guide surface, and in some examples, the micro-refractive element 114c may comprise another material in contact with the light guide surface.

Referring again to fig. 6A, the multibeam element-based display 110 may further include a light source 118. According to various embodiments, the light source 118 is used to provide light that is guided within the light guide 112. In particular, the light source 118 may be located adjacent to an entrance surface or entrance end (input) of the light guide 112. In various embodiments of the present invention, the light source 118 may include substantially any kind of light source (e.g., optical emitter) including, but not limited to, more than one Light Emitting Diodes (LEDs) or lasers (e.g., laser diodes). In some embodiments, light source 118 may include an optical emitter for producing substantially monochromatic light having a narrow spectrum of frequencies representative of a particular color. Specifically, the color of the monochromatic light may be a primary color of a specific color space or a specific color model (e.g., red-green-blue (RGB) color model). In other examples, light source 118 may be a substantially broadband band light source to provide substantially broadband or polychromatic light. For example, light source 118 may provide white light. In some embodiments, the light source 118 may include a plurality of different optical emitters for providing different colors of light. Different optical emitters may be used to provide light having different, color-specific, non-zero value conduction angles of the guided light corresponding to each of the different light colors.

In some embodiments, the light source 118 may further include a collimator (not shown). The collimator may be used to receive substantially non-collimated light from more than one optical emitter of the light source 118. The collimator is further for converting substantially non-collimated light into collimated light. In particular, according to some embodiments, a collimator may provide collimated light having a non-zero conduction angle and collimated according to a predetermined collimation factor. Also, when different color optical emitters are employed, the collimator may be used to provide collimated light having one or both of different, color-specific, non-zero conduction angles and different color-specific collimation factors. The collimator is further used to transmit the collimated beam to the light guide 112 to be conducted as guided light 113, as described above.

According to some embodiments consistent with the principles described herein, the present invention provides a near-eye binocular display system. Fig. 12 illustrates a block diagram of a binocular near-eye display system 200 in one example, according to an embodiment consistent with the principles described herein. The binocular near-eye display system 200 is configured to provide a multi-view image 202 as a pair of stereoscopic images representing a three-dimensional scene (3D), and to forward the pair of stereoscopic images to a corresponding pair of eye boxes 204 for viewing by a user. According to various embodiments, the pair of eye boxes 204 are laterally offset from each other to correspond to the position of the user's eyes. Specifically, the user may comfortably and naturally view the pair of stereoscopic images of the multi-view image 202 in the pair of laterally offset eye boxes 204. Furthermore, according to some embodiments of the present invention, the multi-view images 202 of the pair of stereoscopic images may both provide a 3D experience and may simultaneously address various convergence-accommodation (convergence-accommodation) issues often associated with near-eye stereoscopic displays.

As shown in fig. 12, the binocular near-eye display system 200 includes a pair of multibeam element-based displays 210. According to various embodiments, the multi-beam element based display 210 is used to provide different multi-view images 202 of the pair of stereoscopic images representing the 3D scene. In some embodiments, one or both of the multibeam element based displays 210 of the pair of multibeam element based displays 210 may be substantially similar to the multibeam element based display 110 described above for the near-eye display 100.

In particular, as shown, the multibeam element-based displays 210 each include a light guide 212 and an array of multibeam elements 214 (e.g., as shown). The light guide 212 serves to guide light into guided light. The multibeam element array 214 is to scatter a portion of the guided light into a plurality of directional light beams having principal angular directions corresponding to view directions of different multiview images. In some embodiments, the light guide 212 may be substantially similar to the light guide 112 of the multibeam element-based display 110, while the array of multibeam diffraction gratings 214 may be substantially similar to the array of multibeam diffraction gratings 114 of the multibeam element-based display 110. In particular, the multibeam elements of the multibeam element array 214 may be located at a surface of the light guide 212 or may be adjacent to the surface of the light guide 212. Further, in some embodiments, the multibeam elements in the multibeam element array 214 may include one or more of a diffraction grating, a micro-reflective element, and a micro-refractive element optically connected to the light guide to scatter out the portion of the guided light.

The multibeam element-based display 210 shown in fig. 12 also includes a light valve array 216. The light valve array 216 is used to selectively adjust a directional beam of the plurality of directional beams. According to various embodiments, the selectively adjusted directional light beams may represent different views of the provided multi-view image. In some embodiments, the array of light valves 216 may be substantially similar to the array of light valves 116 of the multibeam element-based display 110 described above. For example, the light valves in the light valve array 216 may include liquid crystal light valves. In other embodiments, the light valve array 216 may include other types of light valves, such as, but not limited to, electrowetting light valves, electrophoretic light valves, combinations thereof, or other types of liquid crystal light valves. In some embodiments, the size of the multibeam elements of the multibeam element array 214 is comparable to the size of the light valves in the light valve array 216 of the multibeam element-based display 210.

According to some embodiments, the various multi-view images 202 of the pair of stereoscopic images provided by the pair of multi-beam element based displays 210 include a plurality of different views of the three-dimensional scene. By way of example, the different view systems represent different views of the three-dimensional scene. Furthermore, in various embodiments, directional beams of the plurality of directional beams may have different principal angular directions corresponding to the view directions of the multi-view image.

The binocular near-eye display system 200 shown in fig. 12 also includes a binocular optical system 220. The binocular optical system 220 forwards the different multi-view images 202 of the pair of stereoscopic images provided by the pair of multibeam element-based displays 210 to a corresponding one of the pair of eye boxes 204, respectively. According to various embodiments, the pair of eye boxes 204 are laterally offset from each other. As noted above, the lateral offset of the eye box 204 may facilitate viewing by a user, for example. The vertical dashed lines in fig. 12 represent the lateral offset between the eye boxes 204.

In some embodiments, although configured in a binocular fashion, binocular optical system 220 may be substantially similar to optical system 120 of near-eye display 100. In particular, binocular optics 220 are used to relay the different views to corresponding different locations in eye box 204. In addition, different locations in the eye box 204 are used to provide depth of focus cues to a user of the binocular near-eye display system 200. In particular, according to various embodiments, the depth of focus cues may correspond to binocular disparity between the multi-view images 202 provided by the pair of stereoscopic images.

Further, according to some embodiments, the binocular optical system 220 may include a first free-form surface prism and a second free-form surface prism (not shown in fig. 12). The first freeform prism may be used to forward a first multi-view image 202 provided by a first multi-beam element based display 210 of the pair of multi-beam element based displays to a first eye box 204 of the pair of eye boxes. Similarly, a second freeform prism can be used to transfer a second multi-view image 202 provided by a second multi-beam element based display 210 of the pair of multi-beam element based displays to a second eye box 204 of the pair of eye boxes. In other embodiments (not shown), the binocular optical system 220 may include a pair of magnifiers (e.g., a pair of loupes similar to loupes 122 described above).

In some embodiments, the binocular near-eye display system 200 is configured as a virtual reality display system. More specifically, the different multi-view images 202 provided by the pair of stereoscopic images may be used at least in the eye-movement range 204 to replace the binocular view in the physical environment. In other embodiments, the near-eye binocular display system 200 shown in fig. 12 may be configured as an augmented reality display system. For example, when used in an augmented reality display system, the different multi-view images 202 provided by the pair of stereoscopic images may augment, but generally do not replace, the physical environment scene in the eye box 204. In other words, the binocular near-eye display system 200 configured as an augmented reality display system provides the user with an optical superposition of the scene of the physical environment and the pair of stereoscopic images. Further, when configured as an augmented reality display, the binocular optical system 220 may further include a pair of free-form surface compensation lenses. According to various embodiments, a free-form surface compensation lens may be used to provide an image of the physical environment to the pair of eye boxes 204.

According to some embodiments, as shown in FIG. 12, the multibeam element-based display 210 may further include a light source 218. The light source 218 is used to provide light to the light guide 212. In some embodiments, the light source 218 may include an optical collimator to collimate the light provided by the light source 218. In some embodiments, the directed light provided by the light source 218 has a predetermined collimation factor. According to some embodiments, the light source 218 may be substantially similar to the light sources 118 of the multi-beam element based display 110 described above for the near-eye display 100.

In accordance with other embodiments consistent with the principles set forth herein, the present invention provides a method of operating a near-eye display. Fig. 13 illustrates a flow chart of a method 300 of operation of a near-eye display in an example, according to an embodiment consistent with the principles described herein. As shown in fig. 13, a method 300 of operating a near-eye display includes a step 310 of using a multi-beam element based multi-view display to provide a multi-view image having a plurality of different views. In some embodiments, the multi-beam element based multi-view display for providing the multi-view image may be substantially similar to the multi-beam element based display 110 described above with respect to the near-eye display 100 in step 310.

In particular, according to various embodiments, a multibeam element-based display includes an array of multibeam elements and an array of light valves. The array of multibeam elements provides a plurality of directional light beams having directions corresponding to various view directions of a plurality of different views. Further, the light valve array modulates the plurality of directional light beams into a multi-view image.

In some embodiments, the array of multibeam elements provides a plurality of directional light beams by scattering a portion of the guided light from the light guide using the array of multibeam elements to produce a plurality of directional light beams having different principal angular directions. In some embodiments, the process of scattering the portion of the guided light includes using a multibeam element of an array of multibeam elements comprising a diffraction grating to diffractively scatter out the portion of the guided light. In some embodiments, scattering the portion of the guided light includes using a multibeam element of a multibeam element array including micro-reflective elements to reflectively scatter out the portion of the guided light. In some embodiments, the process of scattering the portion of the guided light includes using a multibeam element of a multibeam element array including micro-refractive elements to refractively scatter out the portion of the guided light.

As shown in fig. 13, the method 300 of operating a near-eye display further includes a step 320 of forwarding the different views of the multi-view image to an eye box using an optical system. In some embodiments, the optical system may be substantially similar to the optical system 120 of the near-eye display 100 described above. Specifically, according to some embodiments, the step of forwarding different views of the image in step 320 forwards different ones of the different views to different locations in the eye box, thereby providing depth of focus cues to a user viewing the image in the eye box. For example, the depth of focus cue may facilitate image adjustment of the user's eyes.

In some embodiments, the forwarded multi-view image may comprise a three-dimensional image, and different ones of the different views may represent different stereoscopic views of the three-dimensional image. In some embodiments, the image being transferred is a multi-view image of the pair of stereoscopic images. Further, in some examples, the plurality of different views of the image may include at least four different views. In some embodiments, the step 320 of forwarding the plurality of different views of the image comprises magnifying the image to provide a virtual image at a location at a distance from the eye box, wherein the distance corresponds to a normal accommodation range of the user's eyes. In some embodiments, the step 320 of forwarding multiple different views provides a multi-view image of one or both of the augmented reality display and the virtual reality display.

Accordingly, examples and embodiments of a near-eye display, a binocular near-eye display system, and methods of operation of a near-eye display are described herein that employ a multi-beam element based display to provide multiple different views of an image. It should be understood that the above-described examples are merely illustrative of some of the many specific examples that represent the principles described herein. It should be apparent that numerous other arrangements can be readily devised by those skilled in the art without departing from the scope of the invention as defined by the appended claims.

Claims (26)

1. A near-eye display comprising:

a multibeam element based display configured to provide a plurality of different views of a multiview image, the multibeam element based display comprising a multibeam element array configured to provide a plurality of directional beams having directions corresponding to respective view directions of the plurality of different views and a light valve array configured to adjust the plurality of directional beams to provide the multiview image; and

an optical system configured to relay the plurality of different views of the multi-view image to a corresponding plurality of different locations within an eye box at an output of the near-eye display.

2. The near-eye display of claim 1, wherein the corresponding plurality of different locations within the eye box are configured to communicate depth of focus cues to a user of the near-eye display, and wherein different ones of the plurality of different views represent views of different perspectives of the multi-view image.

3. The near-eye display of claim 1, wherein the plurality of different views of the multi-view image comprises at least four different views.

4. The near-eye display of claim 1, wherein the plurality of different views have a full angular range and the optical system has an input aperture, the full angular range configured to correspond to a size of the input aperture.

5. The near-eye display of claim 1, wherein the optical system comprises a simple magnifier configured to provide a virtual image of the multi-view image at a distance from the eye box, the distance corresponding to a normal accommodation range of an eye of a user.

6. The near-eye display of claim 1, wherein the multibeam element-based display and the optical system are both positioned in a field of view of a user to block a portion of the field of view, the near-eye display being a virtual reality display configured to replace a view of a physical environment with the multiview image in the portion of the field of view that is blocked.

7. The near-eye display of claim 1, wherein the multi-beam element based display is located outside a field of view of a user in which the optical system is located, the near-eye display being an augmented reality display configured to augment a view of a physical environment in the field of view with the multi-view image.

8. The near-eye display of claim 1, wherein the optical system comprises a freeform prism.

9. The near-eye display of claim 8, wherein the optical system further comprises a free-form surface compensation lens.

10. The near-eye display of claim 1, wherein the multibeam element based display further comprises a light guide configured to guide light along a length of the light guide as the guided light, the multibeam elements of the multibeam element array configured to scatter a portion of the guided light out of the light guide as directional beams of the plurality of directional beams.

11. The near-eye display of claim 10, wherein the multibeam element comprises a diffraction grating configured to diffractively scatter out the portion of the directed light.

12. The near-eye display of claim 10, wherein the multibeam element comprises one or both of a micro-reflective element configured to reflectively scatter out the portion of the directed light and a micro-refractive element configured to refractively scatter out the portion of the directed light.

13. The near-eye display of claim 10, wherein the multi-beam element based display further comprises a light source optically coupled to an input of the light guide, the light source configured to provide the light to be guided as one or both of the guided light having a non-zero conduction angle and the guided light collimated according to a predetermined collimation factor.

14. A binocular near-eye display system comprising a pair of the near-eye displays of claim 1, wherein a first near-eye display of the pair of near-eye displays is configured to provide a first plurality of different first views of a first multi-view image to a first eye box, a second near-eye display of the pair of near-eye displays is configured to provide a second plurality of different second views of a second multi-view image to a second eye box, the second eye box being laterally offset from the first eye box, the first multi-view image and the second multi-view image representing a pair of stereoscopic images.

15. A binocular near-eye display system comprising:

a pair of multi-beam element based displays, each of the pair of multi-beam element based displays configured to provide a different multi-view image of a pair of stereoscopic images representing a three-dimensional (3D) scene; and

binocular optical systems configured to separately relay the different multi-view images of the pair of stereoscopic images to a corresponding pair of eye boxes, the eye boxes being laterally offset from each other,

wherein the multibeam element-based display of the pair of displays comprises: a light guide configured to guide light as guided light; and a multi-beam element array configured to scatter portions of the guided light as a plurality of directional light beams having principal angular directions corresponding to view directions of the different multi-view images.

16. The binocular near-eye display system of claim 15, wherein the multibeam elements of the multibeam element array comprise one or more of diffraction gratings, micro-reflective elements, and micro-refractive elements optically connected to the light guide to scatter out the portion of the guided light.

17. The binocular near-eye display system of claim 15, wherein the multibeam element based display further comprises a light valve array configured to selectively adjust directional beams of the plurality of directional beams, the selectively adjusted directional beams representing the different views of the provided multiview image, and

wherein the guided light has a predetermined collimation factor, a multibeam element of the array of multibeam elements is located at a surface adjacent to the light guide and has a size comparable to a size of a light valve of the array of light valves of the multibeam element based display.

18. The binocular near-eye display system of claim 15, wherein the binocular optical system is configured to relay a plurality of different views of each of the multi-view images to a corresponding plurality of different positions in the eye box, the different positions of the different views in the eye box configured to provide focal depth cues to a user of the binocular near-eye display system, the focal depth cues corresponding to binocular disparity between the different images of the pair of stereoscopic images.

19. The binocular near-eye display system of claim 15, wherein the binocular optical system includes a first freeform prism configured to relay a first multi-view image provided by a first multi-beam element based display of the pair of multi-beam element based displays to a first eye box of the pair of eye boxes and a second freeform prism configured to relay a second multi-view image provided by a second multi-beam element based display of the pair of multi-beam element based displays to a second eye box of the pair of eye boxes.

20. The binocular near-eye display system of claim 19, wherein the binocular optical system further comprises a pair of freeform compensation lenses configured to provide different images of the physical environment to the pair of eye boxes, the binocular near-eye display system being an augmented reality display system.

21. The binocular near-eye display system of claim 15, wherein the different multi-view images of the pair of stereoscopic images provided are configured to replace a binocular view of a physical environment in the eye box, the binocular near-eye display system configured as a virtual reality display system.

22. A method of operating a near-eye display, comprising:

providing a multi-view image having a plurality of different views using a multi-beam element based multi-view display, the multi-beam element based multi-view display including a multi-beam element array providing a plurality of directional beams having directions corresponding to respective view directions of the plurality of different views, and a light valve array adjusting the plurality of directional beams as the multi-view image; and

forwarding the plurality of different views of the multi-view image to an eye box using an optical system,

wherein the size of the multibeam element in the multibeam element array is equivalent to the size of the light valve in the light valve array.

23. The method of operating the near-eye display of claim 22, wherein the multi-beam element array provides the plurality of directional beams by scattering out portions of the guided light from a light guide that uses the multi-beam element array to produce the plurality of directional beams having different principal angular directions.

24. The method of operating the near-eye display of claim 23, wherein the step of scattering out the portion of the guided light comprises one or more of:

using a multibeam element of the multibeam element array comprising a diffraction grating to diffractively scatter out the portion of the guided light;

using a multibeam element of the multibeam element array comprising micro-reflective elements to reflectively scatter out the portion of the directed light; and

using a multibeam element of the multibeam element array comprising micro-refractive elements to refractively scatter out the portion of the guided light.

25. The method of claim 22, wherein the forwarding the different ones of the plurality of views forwards different ones of the plurality of views to different locations in the eyebox, the different locations of the different ones of the plurality of views providing depth of focus cues to a user viewing the multi-view image in the eyebox.

26. The method of claim 22, wherein the relaying the plurality of different views of the multi-view image provides one or both of an augmented reality display and a virtual reality display of the multi-view image.