Patent Publication Number: US-11650359-B2

Title: Multicolor static multiview display and method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to International Patent Application No. PCT/US2017/053824, filed Sep. 27, 2017, which is incorporated by reference in its entirety herein. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     N/A 
     BACKGROUND 
     Displays and more particularly ‘electronic’ displays are a nearly ubiquitous medium for communicating information to users of a wide variety of devices and products. For example, electronic displays may be found in various devices and applications including, but not limited to, mobile telephones (e.g., smart phones), watches, tablet computes, mobile computers (e.g., laptop computers), personal computers and computer monitors, automobile display consoles, camera displays, and various other mobile as well as substantially non-mobile display applications and devices. Electronic displays generally employ a differential pattern of pixel intensity to represent or display an image or similar information that is being communicated. The differential pixel intensity pattern may be provided by reflecting light incident on the display as in the case of passive electronic displays. Alternatively, the electronic display may provide or emit light to provide the differential pixel intensity pattern. Electronic displays that emit light are often referred to as active displays. 
    
    
     
       BRIEF DESCRIPTION OF THE 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, where like reference numerals designate like structural elements, and in which: 
         FIG.  1 A  illustrates a perspective view of a multiview display in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  1 B  illustrates a graphical representation of angular components of a light beam having a particular principal angular direction corresponding to a view direction of a multiview display in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  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 A  illustrates a plan view of a multicolor static multiview display in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  3 B  illustrates a cross-sectional view of a portion of a multicolor static multiview display in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  3 C  illustrates a perspective view of a multicolor static multiview display in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  4 A  illustrates a plan view of a portion of a multicolor static multiview display including a multicolor light source in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  4 B  illustrates a cross-sectional view of a multicolor light source in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  5    illustrates a plan view of a multicolor static multiview display in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  6 A  illustrates a plan view of a multiview display in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  6 B  illustrates a plan view of the multicolor static multiview display of  FIG.  6 A  in another example, according to an embodiment consistent with the principles described herein. 
         FIG.  7 A  illustrates a plan view of a diffraction grating of a multiview display in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  7 B  illustrates a plan view of a set diffraction gratings organized as a multiview pixel in an example, according to another embodiment consistent with the principles described herein. 
         FIG.  8    illustrates a block diagram of a multicolor static multiview display in an example, according to an embodiment consistent with the principles described herein. 
         FIG.  9    illustrates a flow chart of a method of multicolor static multiview display operation in an example, according to an embodiment consistent with the principles described herein. 
     
    
    
     Certain examples and embodiments have other features that are one of in addition to and in lieu of the features illustrated in the above-referenced figures. These and other features are detailed below with reference to the above-referenced figures. 
     DETAILED DESCRIPTION 
     Examples and embodiments in accordance with the principles described herein provide display of a static or quasi-static three-dimensional (3D) or multiview image having a selectable color (i.e., a ‘color’ multiview image). In particular, embodiments consistent with the principles described display the static or quasi-static color multiview image using a plurality of directional light beams. A color as well as individual intensities and directions of directional light beams of the directional light beam plurality, in turn, correspond to various color view pixels in views of the multicolor multiview image being displayed. According to various embodiments, the individual intensities and, in some embodiments, the individual directions of the directional light beams are predetermined or ‘fixed.’ As such, the displayed color multiview image may be referred to as a static or quasi-static color multiview image. Further, the color of the color multiview image may be selectable as a function of time, according some embodiments 
     As described herein, a multicolor static multiview display configured to display the static or quasi-static color multiview image comprises diffraction gratings optically connected to a light guide to provide the directional light beams having the individual directional light beam intensities and directions. The diffraction gratings are configured to emit or provide the directional light beams by or according to diffractive coupling or scattering out of light guided from within the light guide, the light being guided as a plurality of guided light beams. Further, guided light beams of the guided light beam plurality are guided within the light guide at different radial directions from one another. As such, a diffraction grating of the diffraction grating plurality comprises a grating characteristic that accounts for or that is a function of a particular radial direction of a guided light beam incident on the diffraction grating. In particular, the grating characteristic may be a function of a relative location of the diffraction grating and a light source configured to provide the guided light beam. According to various embodiments, the grating characteristic is configured to account for the radial direction of the guided light beam to insure a correspondence between the emitted directional light beams provide by the diffraction gratings and associated view pixels in various views of the static or quasi-static color multiview image being displayed. 
     Herein, a ‘multiview display’ is defined as an electronic display or display system configured to provide different views of a multiview image in different view directions. A ‘static multiview display’ is a defined as a multiview display configured to display a predetermined or fixed (i.e., static) multiview image, albeit as a plurality of different views. A ‘quasi-static multiview display’ is defined herein as a static multiview display that may be switched between different fixed multiview images or between a plurality of multiview image states, typically as a function of time. Switching between the different fixed multiview images or multiview image states may provide a rudimentary form of animation, for example. Further, as defined herein, a quasi-static multiview display is a type of static multiview display. As such, no distinction is made between a purely static multiview display or image and a quasi-static multiview display or image, unless such distinction is necessary for proper understanding. 
     Further, herein a ‘color’ multiview image is defined as a multiview image having a particular or predefined color. In some embodiments, the predefined color may be selectable. That is, the predefined color may be chosen during operation and further may be changeable as a function of time. For example, during a first time interval the color of the color multiview image may be selected to be or comprise a first color, while the color of the color multiview image may be selected to be or comprise a second color at or during a second time interval. Color selection may be provided by a color-selectable or color-controllable multicolor light source (i.e., a color light source in which a color of provided light is controllable), for example. 
       FIG.  1 A  illustrates a perspective view of a multiview display  10  in an example, according to an embodiment consistent with the principles described herein. As illustrated in  FIG.  1 A , the multiview display  10  comprises a diffraction grating on a screen  12  configured to display a view pixel in a view  14  within or of a multiview image  16  (or equivalently a view  14  of the multiview display  10 ). The multiview image  16  may have a selectable color and therefore may be a color multiview image, for example. The screen  12  may be a display screen of an automobile, a telephone (e.g., mobile telephone, smart phone, etc.), a tablet computer, a laptop computer, a computer monitor of a desktop computer, a camera display, or an electronic display of substantially any other device, for example. 
     The multiview display  10  provides different views  14  of the multiview image  16  in different view directions  18  (i.e., in different principal angular directions) relative to the screen  12 . The view directions  18  are illustrated as arrows extending from the screen  12  in various different principal angular directions. The different views  14  are illustrated as shaded polygonal boxes at the termination of the arrows (i.e., depicting the view directions  18 ). Thus, when the multiview display  10  (e.g., as illustrated in  FIG.  1 A ) is rotated about the y-axis, a viewer sees different views  14 . On the other hand (as illustrated) when the multiview display  10  in  FIG.  1 A  is rotated about the x-axis the viewed image is unchanged until no light reaches the viewer&#39;s eyes (as illustrated). 
     Note that, while the different views  14  are illustrated as being above the screen  12 , the views  14  actually appear on or in a vicinity of the screen  12  when the multiview image  16  is displayed on the multiview display  10  and viewed by the viewer. Depicting the views  14  of the multiview image  16  above the screen  12  as in  FIG.  1 A  is done only for simplicity of illustration and is meant to represent viewing the multiview display  10  from a respective one of the view directions  18  corresponding to a particular view  14 . Further, in  FIG.  1 A  only three views  14  and three view directions  18  are illustrated, all by way of example and not limitation. 
     A view direction or equivalently a light beam having a direction corresponding to a view direction of a multiview display generally has a principal angular direction given by angular components {θ, ϕ}, by 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 angle’ of the light beam. By definition, the elevation angle θ is an angle in a vertical plane (e.g., perpendicular to a plane of the multiview display screen while the azimuth angle ϕ is an angle in a horizontal plane (e.g., parallel to the multiview display screen plane). 
       FIG.  1 B  illustrates a graphical representation of the angular components {θ, ϕ} of a light beam  20  having a particular principal angular direction corresponding to a view direction (e.g., view direction  18  in  FIG.  1 A ) of a multiview display in an example, according to an embodiment consistent with the principles described herein. In addition, the light beam  20  is emitted or emanates from a particular point, by definition herein. That is, by definition, the light beam  20  has a central ray associated with a particular point of origin within the multiview display.  FIG.  1 B  also illustrates the light beam (or view direction) point of origin O. 
     Further herein, the term ‘multiview’ as used in the terms ‘multiview image’ and ‘multiview display’ is defined as a plurality of views representing different perspectives or including angular disparity between views of the view plurality. In addition, herein the term ‘multiview’ explicitly includes more than two different views (i.e., a minimum of three views and generally more than three views), by definition herein. As such, ‘multiview display’ as employed herein is explicitly distinguished from a stereoscopic display that includes only two different views to represent a scene or an image. Note however, while multiview images and multiview displays may include more than two views, by definition herein, multiview images may be viewed (e.g., on a multiview display) as a stereoscopic pair of images by selecting only two of the multiview views to view at a time (e.g., one view per eye). 
     In the multiview display, a ‘multiview pixel’ is defined herein as a set or plurality of view pixels representing pixels in each of a similar plurality of different views of a multiview display. Equivalently, a multiview pixel may have an individual view pixel corresponding to or representing a pixel in each of the different views of the multiview image to be displayed by the multiview display. Moreover, the view pixels of the multiview pixel are so-called ‘directional pixels’ in that each of the view pixels is associated with a predetermined view direction of a corresponding one of the different views, by definition herein. Further, according to various examples and embodiments, the different view pixels represented by the view pixels of a multiview pixel may have equivalent or at least substantially similar locations or coordinates in each of the different views. For example, a first multiview pixel may have individual view pixels corresponding to view pixels located at {x 1 , y 1 } in each of the different views of a multiview image, while a second multiview pixel may have individual view pixels corresponding to view pixels located at {x 2 , y 2 } in each of the different views, and so on. A view pixel having or comprising a particular or predefined (e.g., a selectable) color is a ‘color’ view pixel, by definition herein. 
     In some embodiments, a number of view pixels (or color view pixels) in a multiview pixel may be equal to a number of views of the multiview display. For example, the multiview pixel may provide eight (8) view pixels associated with a multiview display having 8 different views. Alternatively, the multiview pixel may provide sixty-four (64) view pixels associated with a multiview display having 64 different views. In another example, the multiview display may provide an eight by four array of views (i.e., thirty-two views) and the multiview pixel may include thirty-two (32) view pixels (i.e., one for each view). Further, according to some embodiments, a number of multiview pixels of the multiview display may be substantially equal to a number of pixels that make up a selected view of the multiview display. 
     Herein, a ‘light guide’ is defined as a structure that guides light within the structure using total internal reflection. In particular, the light guide may include a core that is substantially transparent at an operational wavelength of the light guide. In various examples, the term ‘light guide’ generally refers to a dielectric optical waveguide that employs total internal reflection to guide light at an interface between a dielectric material of the light guide and a material or medium that surrounds that light guide. By definition, a condition for total internal reflection is that a refractive index of the light guide is greater than a refractive index of a surrounding medium adjacent to a surface of the light guide material. In some embodiments, the light guide may include a coating in addition to or instead of the aforementioned refractive index difference to further facilitate the total internal reflection. The coating may be a reflective coating, for example. The light guide may be any of several light guides including, but not limited to, one or both of a plate or slab guide and a strip guide. 
     Further herein, the term ‘plate’ when applied to a light guide as in a ‘plate light guide’ is defined as a piece-wise or differentially planar layer or sheet, which is sometimes referred to as a ‘slab’ guide. In particular, a plate 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., opposite surfaces) of the light guide. Further, by definition herein, the top and bottom surfaces are both separated from one another and may be substantially parallel to one another in at least a differential sense. That is, within any differentially small section of the plate light guide, the top and bottom surfaces are substantially parallel or co-planar. 
     In some embodiments, the plate light guide may be substantially flat (i.e., confined to a plane) and therefore, the plate light guide is a planar light guide. In other embodiments, the plate light guide may be curved in one or two orthogonal dimensions. For example, the plate light guide may be curved in a single dimension to form a cylindrical shaped plate light guide. However, any curvature has a radius of curvature sufficiently large to ensure that total internal reflection is maintained within the plate light guide to guide light. 
     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 having one or more grating spacings between pairs of the features. For example, the diffraction grating may comprise a plurality of features (e.g., a plurality of grooves or ridges in a material surface) arranged in a one-dimensional (1D) array. In other examples, the diffraction grating may be a two-dimensional (2D) array of features. The diffraction grating may be a 2D array of bumps on or holes in a material surface, for example. According to various embodiments and examples, the diffraction grating may be a sub-wavelength grating having a grating spacing or distance between adjacent diffractive features that is less than about a wavelength of light that is to be diffracted by the diffraction grating. 
     As such, and by definition herein, the ‘diffraction grating’ is a structure that provides diffraction of light incident on the diffraction grating. If the light is incident on the diffraction grating from a light guide, the provided diffraction or diffractive scattering may result in, and thus be referred to as, ‘diffractive coupling’ in that the diffraction grating may couple light out of the light guide by diffraction. The diffraction grating also redirects or changes an angle of the light by diffraction (i.e., at a diffractive angle). In particular, as a result of diffraction, light leaving the diffraction grating generally has a different propagation direction than a propagation direction of the light incident on the diffraction grating (i.e., incident light). The change in the propagation direction of the light by diffraction is referred to as ‘diffractive redirection’ herein. Hence, the diffraction grating may be understood to be a structure comprising diffractive features that diffractively redirects light incident on the diffraction grating and, if the light is incident from a light guide, the diffraction grating may also diffractively couple out the light from the light guide. 
     Further, by definition herein, the features of a diffraction grating are referred to as ‘diffractive features’ and may be one or more of at, in and on a material surface (i.e., a boundary between two materials). The surface may be a surface of a light guide, for example. The diffractive features may include any of a variety of structures that diffract light including, but not limited to, one or more of grooves, ridges, holes and bumps at, in or on the surface. For example, the diffraction grating may include a plurality of substantially parallel grooves in the material surface. In another example, the diffraction grating may include a plurality of parallel ridges rising out of the material surface. The diffractive features (e.g., grooves, ridges, holes, bumps, etc.) may have any of a variety of cross-sectional shapes or profiles that provide diffraction including, but not limited to, one or more of a sinusoidal profile, a rectangular profile (e.g., a binary diffraction grating), a triangular profile and a saw tooth profile (e.g., a blazed grating). 
     As described further below, a diffraction grating herein may have a grating characteristic, including one or more of a feature spacing or pitch, an orientation and a size (such as a width or length of the diffraction grating). Further, the grating characteristic may selected or chosen to be a function of the angle of incidence of light beams on the diffraction grating, a distance of the diffraction grating from a light source (e.g., a multicolor light source) or both. In particular, the grating characteristic of a diffraction grating may be chosen to depend on a relative location of the light source and a location of the diffraction grating, according to some embodiments. By appropriately varying the grating characteristic of the diffraction grating, both an intensity and a principal angular direction of a light beam diffracted (e.g., diffractively coupled-out of a light guide) by the diffraction grating (i.e., a ‘directional light beam’) corresponds to an intensity and a view direction of a view pixel of the multiview image. 
     According to various examples described herein, a diffraction grating (e.g., a diffraction grating of a multiview pixel, as described below) may be employed to diffractively scatter or couple light out of a light guide (e.g., a plate light guide) as a light beam. In particular, a diffraction angle θ m  of or provided by a locally periodic diffraction grating may be given by equation (1) as: 
                     θ   m     =       sin     -   1       ⁡     (       n   ⁢   sin   ⁢     θ   i       -       m   ⁢           ⁢   λ     d       )               (   1   )               
where λ is a wavelength of the light, m is a diffraction order, n is an index of refraction of a light guide, d is a distance or spacing between features of the diffraction grating, θ i  is an angle of incidence of light on the diffraction grating. For simplicity, equation (1) assumes that the diffraction grating is adjacent to a surface of the light guide and a refractive index of a material outside of the light guide is equal to one (i.e., n out =1). In general, the diffraction order m is given by an integer. A diffraction angle θ m  of a light beam produced by the diffraction grating may be given by equation (1) where the diffraction order is positive (e.g., m&gt;0). For example, first-order diffraction is provided when the diffraction order m is equal to one (i.e., m=1).
 
       FIG.  2    illustrates a cross-sectional view of a diffraction grating  30  in an example, according to an embodiment consistent with the principles described herein. For example, the diffraction grating  30  may be located on a surface of a light guide  40 . In addition,  FIG.  2    illustrates a light beam (or a collection of light beams)  50  incident on the diffraction grating  30  at an incident angle θ i . The light beam  50  is a guided light beam within the light guide  40 . Also illustrated in  FIG.  2    is a coupled-out light beam (or a collection of light beams)  60  diffractively produced and coupled-out by the diffraction grating  30  as a result of diffraction of the incident light beam  20 . The coupled-out light beam  60  has a diffraction angle θ m  (or ‘principal angular direction’ herein) as given by equation (1). The coupled-out light beam  60  may correspond to a diffraction order ‘m’ of the diffraction grating  30 , for example. 
     According to various embodiments, the principal angular direction of the various light beams is determined by the grating characteristic including, but not limited to, one or more of a size (e.g., a length, a width, an area, etc.) of the diffraction grating, an orientation, and a feature spacing. Further, a light beam produced by the diffraction grating has a principal angular direction given by angular components {θ, ϕ}, by definition herein, and as described above with respect to  FIG.  1 B . 
     Herein, a ‘collimated light’ or ‘collimated light beam’ is generally defined as a beam of light in which rays of the light beam are substantially parallel to one another within the light beam (e.g., the guided light beam in the light guide). Further, rays of light that diverge or are scattered from the collimated light beam are not considered to be part of the collimated light beam, by definition herein. Moreover, herein a ‘collimator’ is defined as substantially any optical device or apparatus that is configured to collimate light. 
     Herein, a ‘collimation factor’ is defined as a degree to which light is collimated. In particular, a collimation factor defines an angular spread of light rays within a collimated beam of light, by definition herein. For example, a collimation factor σ may specify that a majority of light rays in a beam of collimated light is within a particular angular spread (e.g., +/−σ degrees about a central or principal angular direction of the collimated light beam). The light rays of the collimated light beam may have a Gaussian distribution in terms of angle and the angular spread be an angle determined by at one-half of a peak intensity of the collimated light beam, according to some examples. 
     Herein, a ‘light source’ is defined as a source of light (e.g., an optical emitter configured to produce and emit light). A ‘multicolor light source’ is a source of light having or comprising a selectable color of the emitted light. For example, the light source may comprise an optical emitter such as a light emitting diode (LED) that emits light when activated or turned on. Likewise, the multicolor light source may comprise a color-selectable or color-variable optical emitter or a plurality of optical emitters of different colors that provides different colors of the emitted light in a selectable manner. For example, the multicolor light source may comprise a plurality of different color optical emitters such as a plurality of different color LEDs that emit different colors of light when activated. 
     In particular, herein the multicolor light source may be substantially any source of light or comprise substantially any optical emitter including, but not limited to, one or more of a light emitting diode (LED), a laser, an organic light emitting diode (OLED), a polymer light emitting diode, a plasma-based optical emitter, a fluorescent lamp, an incandescent lamp, and virtually any other source of light that may be rendered or configured to be color-selectable. The light produced by the multicolor light source may have a plurality of different colors (i.e., may include a plurality of different particular wavelengths of light). In some embodiments, the light source may comprise a plurality of different color optical emitters. For example, the light source may include a set or group of optical emitters in which at least one of the optical emitters produces light having a color, or equivalently a wavelength, that differs from a color or wavelength of light produced by at least one other optical emitter of the set or group. The different colors may include primary colors (e.g., red, green, blue) for example. Further, the selectable color may be provided by combining the different colors of light produced by the various optical emitters, according to various embodiments. 
     Further, as used herein, the article ‘a’ is intended to have its ordinary meaning in the patent arts, namely ‘one or more’. For example, ‘a diffraction grating’ means one or more diffraction gratings and as such, ‘the diffraction grating’ means ‘the diffraction grating(s)’ herein. Also, any reference herein to ‘top’, ‘bottom’, ‘upper’, ‘lower’, ‘up’, ‘down’, ‘front’, back’, ‘first’, ‘second’, ‘left’ or ‘right’ is not intended to be a limitation herein. Herein, the term ‘about’ when applied to a value generally means within the tolerance range 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 otherwise expressly specified. Further, the term ‘substantially’ as used herein means a majority, or almost all, or all, or an amount within a range of about 51% to about 100%. Moreover, examples herein are intended to be illustrative only and are presented for discussion purposes and not by way of limitation. 
     According to some embodiments of the principles described herein, a multiview display configured to provide multiview images and more particularly color static multiview images is provided.  FIG.  3 A  illustrates a plan view of a multicolor static multiview display  100  in an example, according to an embodiment consistent with the principles described herein.  FIG.  3 B  illustrates a cross-sectional view of a portion of a multicolor static multiview display  100  in an example, according to an embodiment consistent with the principles described herein. In particular,  FIG.  3 B  may illustrate a cross section through a portion of the multicolor static multiview display  100  of  FIG.  3 A , the cross section being in an x-z plane.  FIG.  3 C  illustrates a perspective view of a multicolor static multiview display  100  in an example, according to an embodiment consistent with the principles described herein. According to some embodiments, the illustrated multicolor static multiview display  100  is configured to provide a single color static multiview image, while in others the multicolor static multiview display  100  may be configured to provide a plurality of color multiview images and therefore functions as (or is) a color quasi-static multiview display  100 . For example, the multicolor static multiview display  100  may be switchable between different fixed color multiview images or equivalently between a plurality of color multiview image states, as described below. 
     The multicolor static multiview display  100  illustrated in  FIGS.  3 A- 3 C  is configured to provide a plurality of directional light beams  102 , each directional light beam  102  of the plurality having an intensity and a principal angular direction. Together, the plurality of directional light beams  102  has a selectable color and represents various color view pixels of a set of views of a color multiview image that the multicolor static multiview display  100  is configured to provide or display. In some embodiments, the color view pixels may be organized into multiview pixels to represent the various different views of the color multiview images. Further, the color view pixels comprise a color and more particularly a selectable color of the multicolor static multiview display  100 . 
     As illustrated, the multicolor static multiview display  100  comprises a light guide  110 . The light guide may be a plate light guide (as illustrated), for example. The light guide  110  is configured to guide light along a length of the light guide  110  as guided light or more particularly as guided light beams  112 . For example, the light guide  110  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 surrounding the dielectric optical waveguide. The difference in refractive indices is configured to facilitate total internal reflection of the guided light beams  112  according to one or more guided modes of the light guide  110 , for example. 
     In some embodiments, the light guide  110  may be a slab or plate optical waveguide comprising an extended, substantially planar sheet of optically transparent, dielectric material. The substantially planar sheet of dielectric material is configured to guide the guided light beams  112  using total internal reflection. According to various examples, the optically transparent material of the light guide  110  may include or be made up of any of a variety of dielectric materials including, but not limited to, one or more of various types of glass (e.g., silica 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  110  may further include a cladding layer (not illustrated) on at least a portion of a surface (e.g., one or both of the top surface and the bottom surface) of the light guide  110 . The cladding layer may be used to further facilitate total internal reflection, according to some examples. 
     According to various embodiments, the light guide  110  is configured to guide the guided light beams  112  according to total internal reflection at a non-zero propagation angle between a first surface  110 ′ (e.g., a ‘front’ surface) and a second surface  110 ″ (e.g., a ‘back’ or ‘bottom’ surface) of the light guide  110 . In particular, the guided light beams  112  propagate by reflecting or ‘bouncing’ between the first surface  110 ′ and the second surface  110 ″ of the light guide  110  at the non-zero propagation angle. Note, the non-zero propagation angle is not explicitly depicted in  FIG.  3 B  for simplicity of illustration. However,  FIG.  3 B  does illustrate an arrow pointing into a plane of the illustration depicting a general propagation direction  103  of the guided light beams  112  along the light guide length. 
     As defined herein, a ‘non-zero propagation angle’ is an angle relative to a surface (e.g., the first surface  110 ′ or the second surface  110 ″) of the light guide  110 . Further, the non-zero propagation angle is both greater than zero and less than a critical angle of total internal reflection within the light guide  110 , according to various embodiments. For example, the non-zero propagation angle of the guided light beam  112  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 propagation angle may be about thirty (30) degrees. In other examples, the non-zero propagation angle may be about 20 degrees, or about 25 degrees, or about 35 degrees. Moreover, a specific non-zero propagation angle may be chosen (e.g., arbitrarily) for a particular implementation as long as the specific non-zero propagation angle is chosen to be less than the critical angle of total internal reflection within the light guide  110 . 
     As illustrated in  FIGS.  3 A and  3 C , the multicolor static multiview display  100  further comprise a multicolor light source  120 . The multicolor light source  120  is located at an input location  116  on the light guide  110 . For example, the multicolor light source  120  may be located adjacent to an edge or side  114  of the light guide  110 , as illustrated. The multicolor light source  120  is configured to provide light within the light guide  110  as the plurality of guided light beams  112 . The plurality of guided light beams  112  comprise a selectable color of light or simply a ‘selectable color’. Further, the multicolor light source  120  provides the light such that individual guided light beams  112  of the guided light beam plurality have different radial directions  118  from one another. 
     In particular, light emitted by the multicolor light source  120  is configured enter the light guide  110  and to propagate as the plurality of guided light beams  112  in a radial pattern away from the input location  116  and across or along a length of the light guide  110 . Further, the individual guided light beams  112  of the guided light beam plurality have different radial directions from one another by virtue of the radial pattern of propagation away from the input location  116 . For example, the multicolor light source  120  may be butt-coupled to the side  114 . The multicolor light source  120  being butt-coupled may facilitate introduction of light in a fan-shape pattern to provide the different radial directions of the individual guided light beams  112 , for example. According to some embodiments, the multicolor light source  120  may be or at least approximate a ‘point’ source of light at the input location  116  such that the guided light beams  112  propagate along the different radial directions  118  (i.e., as the plurality of guided light beams  112 ). 
     In some embodiments, the input location  116  of the multicolor light source  120  is on a side  114  of the light guide  110  near or about at a center or a middle of the side  114 . In particular, in  FIGS.  3 A and  3 C , the multicolor light source  120  is illustrated at an input location  116  that is approximately centered on (e.g., at a middle of) the side  114  (i.e., the ‘input side’) of the light guide  110 . Alternatively (not illustrated), the input location  116  may be away from the middle of the side  114  of the light guide  110 . For example, the input location  116  may be at a corner of the light guide  110 . For example, the light guide  110  may have a rectangular shape (e.g., as illustrated) and the input location  116  of the multicolor light source  120  may be at a corner of the rectangular-shaped light guide  110  (e.g., a corner of the input side  114 ). 
     In various embodiments, the multicolor light source  120  may comprise substantially any source of light (e.g., optical emitter) configured to provide a selectable color of light including, but not limited to, one or more light emitting diodes (LEDs) or a laser (e.g., laser diode). In some embodiments, the multicolor light source  120  may comprise an optical emitter configured produce a substantially monochromatic light having a narrowband spectrum denoted by a particular color (e.g., a first color). In particular, the color of the monochromatic light may be a primary color of a particular color space or color model (e.g., an RGB color model). The multicolor light source  120  may thus comprise a plurality of different color optical emitters that produce different colors of substantially monochromatic light to facilitate emission of the selectable color of light, for example. In other examples, the multicolor light source  120  may be a substantially broadband light source configured to provide substantially broadband or polychromatic light comprising a selectable output color. For example, the multicolor light source  120  may provide white light, a band of which may be selected to provide the selectable color of light (or selectable color). Selection of the selectable color may be provided by a control input to the multicolor light source  120 , for example. In another example, color selection may be provided by a variable color filter at an output of the multicolor light source  120 . 
     As mentioned above, the multicolor light source  120  may comprise a plurality of color optical emitters configured to provide different colors of light. The different optical emitters may be configured to provide light having different, color-specific, non-zero propagation angles of the guided light corresponding to each of the different colors of light. Further, in some embodiments, optical emitters of the optical emitter plurality configured to provide a first color (e.g., red) of the different colors of light may be interlaced or interspersed with optical emitters configured to provide a second or another color (e.g., green or blue) of the different colors of light within the multicolor light source  120 . For example, the plurality of color optical emitters may comprise a red light emitting diode, a green light emitting diode, and a blue light emitting diode. Thus, the different colors of light may be red light, green light, and blue light such that the selectable color is provided as a selectable combination of the red, green and blue light. The selectable combination may be controlled by a relative emission intensity of the red, green, blue light emitting diodes, for example. Further in the example, the red, green, and blue light emitting diodes may be interlaced or interspersed with one another across an extent or a width of the multicolor light source  120 . 
       FIG.  4 A  illustrates a plan view of a portion of a multicolor static multiview display  100  including a multicolor light source  120  in an example, according to an embodiment consistent with the principles described herein.  FIG.  4 B  illustrates a cross-sectional view of a multicolor light source  120  in an example, according to an embodiment consistent with the principles described herein. In particular,  FIG.  4 A  illustrates the multicolor light source  120  as being butt-coupled to the side  114  of the light guide  110  of the multicolor static multiview display  100 . Different types of arrows (solid, long dash, and short dash) represent different colors of light within guided light beams  112  produced by the multicolor light source  120 . The different colors combine to provide the selectable color of the guided light beams  112 , as illustrated. 
     The multicolor light source  120  illustrated in  FIG.  4 B  comprises a plurality of color optical emitters  122  configured to provide different colors of light. Further, as illustrated, the color optical emitters  122  comprise a first optical emitter  122 ′ configured to provide a first color of light (e.g., red light), a second optical emitter  122 ″ configured to provide a second color of light (e.g., green light), and a third optical emitter  122 ′″ configured to provide a third color of light (e.g., blue light). For example, the plurality of color optical emitters  122  may comprise a plurality of different color light emitting diodes (LEDs). The first optical emitter  122 ′ may be a red LED, the second optical emitter  122 ″ may be a green LED, and the third optical emitter  122 ′″ may be a blue LED, for example. Further, the first optical emitter  122 ′, the second optical emitter  122 ″, and third optical emitter  122 ′″ are interlaced within an extent W of the multicolor light source  120 , as illustrated. That is, the first, second and third optical emitters  122 ′,  122 ″,  122 ′″ are small enough to fit within the multicolor light source extent W and further alternate with each other across the extent W as illustrated. Interlacing of the color optical emitters  122  having different colors may facilitate combining or ‘blending together’ the different colors of light produced, for example. Further, interlacing may also result in light rays of different colors within the guided light beams  112  having substantially the same propagation direction (i.e., a common direction of the guided light beam  112 , as illustrated in  FIG.  4 A ). Note that the extent W may be chosen to determine or be used to control an angular spread of a color view pixel, according to some embodiments. 
     In some embodiments, the guided light beams  112  comprising or having a selectable color produced by coupling light from the multicolor light source  120  into the light guide  110  may be uncollimated or at least substantially uncollimated. In other embodiments, the guided light beams  112  may be collimated (i.e., the guided light beams  112  may be collimated light beams). As such, in some embodiments, the multicolor static multiview display  100  may include a collimator (not illustrated) between the multicolor light source  120  and the light guide  110 . Alternatively, the multicolor light source  120  may further comprise a collimator. The collimator is configured to provide guided light beams  112  within the light guide  110  that are collimated. In particular, the collimator is configured to receive substantially uncollimated light from one or more of the optical emitters of the multicolor light source  120  and to convert the substantially uncollimated light into collimated light. In some examples, the collimator may be configured to provide collimation in a plane (e.g., a ‘vertical’ plane) that is substantially perpendicular to the propagation direction of the guided light beams  112 . That is, the collimation may provide collimated guided light beams  112  having a relatively narrow angular spread in a plane perpendicular to a surface of the light guide  110  (e.g., the first or second surface  110 ′,  110 ″), for example. According to various embodiments, the collimator may comprise any of a variety of collimators including, but not limited to a lens, a reflector or mirror (e.g., tilted collimating reflector), or a diffraction grating (e.g., a diffraction grating-based barrel collimator) configured to collimate the light, e.g., from the multicolor light source  120 . 
     Further, in some embodiments, the collimator may provide collimated light one or both of having the non-zero propagation angle and being collimated according to a predetermined collimation factor. Moreover, when optical emitters of different colors are employed, the collimator may be configured to provide the collimated light having one or both of different, color-specific, non-zero propagation angles and having different color-specific collimation factors. The collimator is further configured to communicate the collimated light to the light guide  110  to propagate as the guided light beams  112 , in some embodiments. 
     Use of collimated or uncollimated light may impact the color multiview image that may be provided by the multicolor static multiview display  100 , in some embodiments. For example, if the guided light beams  112  comprising or having a selectable color are collimated within the light guide  110 , the emitted directional light beams  102  also comprising or having the selectable color may have a relatively narrow or confined angular spread in at least two orthogonal directions. Thus, the multicolor static multiview display  100  may provide a color multiview image having a plurality of different views in an array having two different directions (e.g., an x-direction and a y-direction). However, if the guided light beams  112  are substantially uncollimated, the color multiview image may provide view parallax, but may not provide a full, two-dimensional array of different views. In particular, if the guided light beams  112  are uncollimated (e.g., along the z-axis), the color multiview image may provide different color multiview images exhibiting ‘parallax 3D’ when rotated about the y-axis (e.g., as illustrated in  FIG.  1 A ). On the other hand, if the multicolor static multiview display  100  is rotated around the x-axis, for example, the color multiview image and views thereof may remain substantially unchanged or the same because the directional light beams  102  of the directional light beam plurality have a broad angular range within the y-z plane. Thus, the color multiview image provided may be ‘parallax only’ providing an array of views in only one direction and not two. 
     Referring again to  FIGS.  3 A- 3 C , the illustrated multicolor static multiview display  100  further comprises a plurality of diffraction gratings  130  configured to emit directional light beams  102  of the directional light beam plurality. As mentioned above and according to various embodiments, the directional light beams  102  emitted by the plurality of diffraction gratings  130  may represent a color multiview image. In particular, the directional light beams  102  emitted by the plurality of diffraction gratings  130  may be configured to create the color multiview image to display information, e.g., information having 3D content. Further, the diffraction gratings  130  may emit the directional light beams  102  comprising the selectable color when the light guide  110  is illuminated from the side  114  by the multicolor light source  120 , as is further described below. 
     According to various embodiments, a diffraction grating  130  of the diffraction grating plurality are configured to provide from a portion of a guided light beam  112  of the guided light beam plurality a directional light beam  102  of the directional light beam plurality. Further, the diffraction grating  130  is configured to provide the directional light beam  102  having both an intensity and a principal angular direction corresponding to an intensity and a view direction of a color view pixel of the color multiview image. In some embodiments, the diffraction gratings  130  of the diffraction grating plurality generally do not intersect, overlap or otherwise touch one another, according to some embodiments. That is, each diffraction grating  130  of the diffraction grating plurality is generally distinct and separated from other ones of the diffraction gratings  130 , according to various embodiments. 
     As illustrated in  FIG.  3 B , the directional light beams  102  may, at least in part, propagate in a direction that differs from and in some embodiments is orthogonal to an average or general propagation direction  103  of a guided light beams  112  within the light guide  110 . For example, as illustrated in  FIG.  3 B , the directional light beam  102  from a diffraction grating  130  may be substantially confined to the x-z plane, according to some embodiments. 
     According to various embodiments, each of the diffraction gratings  130  of the diffraction grating plurality has an associated grating characteristic. The associated grating characteristic of each diffraction grating depends on, is defined by, or is a function of a radial direction  118  of the guided light beam  112  incident on the diffraction grating from the multicolor light source  120 . Further, in some embodiment, the associated grating characteristic is further determined or defined by a distance between the diffraction grating  130  and the input location  116  of the multicolor light source  120 . For example, the associated characteristic may be a function of the distance D between diffraction grating  130   a  and input location  116  and the radial direction  118   a  of the guided light beam  112  incident on the diffraction grating  130   a , as illustrated in  FIG.  3 A . Stated differently, an associated grating characteristic of a diffraction grating  130  in the plurality of the diffraction gratings  130  depends on the input location  116  of the light source and a particular location of the diffraction grating  130  on a surface of the light guide  110  relative to the input location  116 . 
       FIG.  3 A  illustrates two different diffraction gratings  130   a  and  130   b  having different spatial coordinates (x 1 , y 1 ) and (x 2 , y 2 ), which further have different grating characteristics to compensate or account for the different radial directions  118   a  and  118   b  of the plurality of guided light beams  112  from the multicolor light source  120  that are incident on the diffraction gratings  130 . Similarly, the different grating characteristics of the two different diffraction gratings  130   a  and  130   b  account for different distances of the respective diffraction gratings  130   a ,  130   b  from the light source input location  116  determined by the different spatial coordinates (x 1 , y 1 ) and (x 2 , y 2 ). 
       FIG.  3 C  illustrates an example of a plurality of directional light beams  102  that may be provided by the multicolor static multiview display  100 . In particular, as illustrated, different sets of diffraction gratings  130  of the diffraction grating plurality are illustrated emitting directional light beams  102  having different principal angular directions from one another. The different principal angular directions may correspond to different view directions of the multicolor static multiview display  100 , according to various embodiments. For example, a first set of the diffraction gratings  130  may diffractively couple out portions of incident guided light beams  112  (illustrated as dashed lines) to provide a first set of directional light beams  102 ′ having a first principal angular direction corresponding to a first view direction (or a first view) of the multicolor static multiview display  100 . Similarly, a second set of directional light beams  102 ″ and a third set of directional light beams  102 ″′ having principal angular directions corresponding to a second view direction (or a second view) and a third view direction (or third view), respectively of the multicolor static multiview display  100  may be provided by diffractive coupling out of portions of incident guided light beams  112  by respective second third sets of diffraction gratings  130 , and so on, as illustrated. Also illustrated in  FIG.  3 C  are a first view  14 ′, a second view  14 ″, and a third view  14 ″′, of a color multiview image  16  that may be provided by the multiview display  100 . The illustrated first, second, and third views  14 ′,  14 ″,  14 ″′, represent different perspective views of an object and collectively are the displayed color multiview image  16  (e.g., equivalent to the color multiview image  16  illustrated in  FIG.  1 A ). 
     In general, the grating characteristic of a diffraction grating  130  may include one or more of a diffractive feature spacing or pitch, a grating orientation and a grating size (or extent) of the diffraction grating. Further, in some embodiments, a diffraction-grating coupling efficiency (such as the diffraction-grating area, the groove depth or ridge height, etc.) may be a function of the distance from the input location  116  to the diffraction grating. For example, the diffraction grating coupling efficiency may be configured to increase as a function of distance, in part, to correct or compensate for a general decrease in the intensity of the guided light beams  112  associated with the radial spreading and other loss factors. Thus, an intensity of the directional light beam  102  provided by the diffraction grating  130  and corresponding to an intensity of a corresponding view pixel may be determined, in part, by a diffractive coupling efficiency of the diffraction grating  130 , according to some embodiments. 
       FIG.  5    illustrates a plan view of a multicolor static multiview display  100  in an example, according to an embodiment consistent with the principles described herein. In  FIG.  5   , illumination volumes  134  in an angular space that is a distance D from input location  116  of the multicolor light source  120  at the side  114  of the light guide  110  are shown. Note that the illumination volume has a wider angular size as the radial direction of propagation of the plurality of guided light beams  112  changes in angle away from they-axis and towards the x-axis. For example, illumination volume  134   b  is wider than illumination volume  134   a , as illustrated. 
     Referring again to  FIG.  3 B , the plurality of diffraction gratings  130  may be located at or adjacent to the first surface  110 ′ of the light guide  110 , which is the light beam emission surface of the light guide  110 , as illustrated. For example, the diffraction gratings  130  may be transmission mode diffraction gratings configured to diffractively couple out the guided light portion through the first surface  110 ′ as the directional light beams  102 . Alternatively, the plurality of diffraction gratings  130  may be located at or adjacent to the second surface  110 ″ opposite from a light beam emission surface of the light guide  110  (i.e., the first surface  110 ′). In particular, the diffraction gratings  130  may be reflection mode diffraction gratings. As reflection mode diffraction gratings, the diffraction gratings  130  are configured to both diffract the guided light portion and to reflect the diffracted guided light portion toward the first surface  110 ′ to exit through the first surface  110 ′ as the diffractively scattered or coupled-out directional light beams  102 . In other embodiments (not illustrated), the diffraction gratings  130  may be located between the surfaces of the light guide  110 , e.g., as one or both of a transmission mode diffraction grating and a reflection mode diffraction grating. 
     In some embodiments described herein, the principal angular directions of the directional light beams  102  may include an effect of refraction due to the directional light beams  102  exiting the light guide  110  at a light guide surface. For example, when the diffraction gratings  130  are located at or adjacent to second surface  110 ″, the directional light beams  102  may be refracted (i.e., bent) because of a change in refractive index as the directional light beams  102  cross the first surface  110 ′, by way of example and not limitation. 
     According to some embodiment, the multicolor static multiview display  100  may comprise a plurality of multicolor light sources  120  that are laterally offset from one another. The lateral offset of multicolor light sources  120  of the light source plurality may provide a difference in the radial directions of various guided light beams  102  at or between individual diffraction gratings  130 . The difference, in turn, may facilitate providing animation of a displayed color multiview image, according to some embodiments. Thus, the multicolor static multiview display  100  may be a multicolor quasi-static multiview display  100 , in some embodiments. 
       FIG.  6 A  illustrates a plan view of a multicolor static multiview display  100  in an example, according to an embodiment consistent with the principles described herein.  FIG.  6 B  illustrates a plan view of the multicolor static multiview display  100  of  FIG.  6 A  in another example, according to an embodiment consistent with the principles described herein. The multicolor static multiview display  100  illustrated in  FIGS.  6 A and  6 B  comprises a light guide  110  with a plurality of diffraction gratings  130 . In addition, the multicolor static multiview display  100  further comprises a plurality of multicolor light sources  120  that are laterally offset from each other and configured to separately provide guided light beams  112  having different radial directions  118  from one another, as illustrated. 
     In particular,  FIGS.  6 A and  6 B  illustrate a first multicolor light source  120   a  at a first input location  116   a  and a second multicolor light source  120   b  at a second input location  116   b  on the side  114  of the light guide  110 . The first and second input locations  116   a ,  116   b  are laterally offset or shifted from one another along the side  114  (i.e., in an x-direction) to provide the lateral offset of respective first and second multicolor light sources  120   a ,  120   b . Additionally, each of the first and second multicolor light sources  120   a ,  120   b  of the plurality of multicolor light sources  120  provide a different plurality of guided light beams  112  comprising a selectable color and having respective different radial directions from one another. For example, the first multicolor light source  120   a  may provide a first plurality of guided light beams  112   a  having a first set of different radial directions  118   a  and the second multicolor light source  120   b  may provide a second plurality of guided light beams  112   b  having a second set of different radial directions  118   b , as illustrated in  FIGS.  6 A and  6 B , respectively. Further, the first and second pluralities of guided light beams  112   a ,  112   b  generally have sets of different radial directions  118   a ,  118   b  that also differ from one another as sets by virtue of the lateral offset of the first and second multicolor light sources  120   a ,  120   b , as illustrated. 
     Thus, the plurality of diffraction gratings  130  emit directional light beams representing different color multiview images that are shifted in a view space from one another (e.g., angularly shifted in view space). Thus, by switching between the first and second multicolor light sources  120   a ,  120   b , the multicolor static multiview display  100  may provide ‘animation’ of the color multiview images, such as a time-sequenced animation. In particular, by sequentially illuminating the first and second multicolor light sources  120   a ,  120   b  during different sequential time intervals or periods, multicolor static multiview display  100  may be configured to shift an apparent location of the color multiview image during the different time periods, for example. This shift in apparent location provided by the animation may represent and example of operating the multicolor static multiview display  100  as a multicolor quasi-static multiview display  100  to provide a plurality of color multiview image states, according to some embodiments. 
     In addition, the selectable color provided by the first multicolor light source  120   a  may be the same or a different color than the selectable color provided by the second multicolor light source  120   b , according to various embodiments. As such, the ‘animation’ may include a change in the color of the color multiview images as a function of time (e.g., in a particular color multiview image) or as a function of color multiview image state. 
     According to various embodiments, as described above with respect to  FIGS.  3 A- 3 C , the directional light beams  102  of the multicolor static multiview display  100  are emitted using diffraction (e.g., by diffractive scattering or diffractive coupling). In some embodiments, the plurality of the diffraction gratings  130  may be organized as multiview pixels, each multiview pixel including a set of diffraction gratings  130  comprising one or more diffraction gratings  130  from the diffraction grating plurality. Further, as has been discussed above, the diffraction grating(s)  130  have diffraction characteristics that are a function of radial location on the light guide  110  as well as being a function of an intensity and direction of the directional light beams  102  emitted by the diffraction grating(s)  130 . 
       FIG.  7 A  illustrates a plan view of a diffraction grating  130  of a multiview display in an example, according to an embodiment consistent with the principles described herein.  FIG.  7 B  illustrates a plan view of a set of diffraction gratings  130  organized as a multiview pixel  140  in an example, according to another embodiment consistent with the principles described herein. As illustrated in  FIGS.  7 A and  7 B , each of the diffraction gratings  130  comprises a plurality of diffractive features spaced apart from one another according to a diffractive feature spacing (which is sometimes referred to as a ‘grating spacing’) or grating pitch. The diffractive feature spacing or grating pitch is configured to provide diffractive coupling out or scattering of the guided light portion from within the light guide. In  FIGS.  7 A- 7 B , the diffraction gratings  130  are on a surface of a light guide  110  of the multiview display (e.g., the multicolor static multiview display  100  illustrated in  FIGS.  3 A- 3 C ). 
     According to various embodiments, the spacing or grating pitch of the diffractive features in the diffraction grating  130  may be sub-wavelength (i.e., less than a wavelength of the guided light beams  112 ). Note that, while  FIGS.  7 A and  7 B  illustrate the diffraction gratings  130  having a single or uniform grating spacing (i.e., a constant grating pitch), for simplicity of illustration. In various embodiments, as described below, the diffraction grating  130  may include a plurality of different grating spacings (e.g., two or more grating spacings) or a variable diffractive feature spacing or grating pitch to provide the directional light beams  102 , e.g., as is variously illustrated in  FIGS.  3 A- 6 B . Consequently,  FIGS.  7 A and  7 B  are not intended to imply that a single grating pitch is an exclusive embodiment of diffraction grating  130 . 
     According to some embodiments, the diffractive features of the diffraction grating  130  may comprise one or both of grooves and ridges that are spaced apart from one another. The grooves or the ridges may comprise a material of the light guide  110 , e.g., the groove or ridges may be formed in a surface of the light guide  110 . In another example, the grooves or the ridges may be formed from a material other than the light guide material, e.g., a film or a layer of another material on a surface of the light guide  110 . 
     As discussed previously and shown in  FIG.  7 A , the configuration of the diffraction features comprises a grating characteristic of the diffraction grating  130 . For example, a grating depth of the diffraction grating may be configured to determine the intensity of the directional light beams  102  provided by the diffraction grating  130 . Alternatively or additionally, discussed previously and shown in  FIGS.  7 A- 7 B , the grating characteristic comprises one or both of a grating pitch of the diffraction grating  130  and a grating orientation (e.g., the grating orientation y illustrated in  FIG.  7 A ). In conjunction with the angle of incidence of the guided light beams, these grating characteristics determine the principal angular direction of the directional light beams  102  provided by the diffraction grating  130 . 
     In some embodiments (not illustrated), the diffraction grating  130  configured to provide the directional light beams comprises a variable or chirped diffraction grating as a grating characteristic. By definition, the ‘chirped’ diffraction grating is a diffraction grating exhibiting or having a diffraction spacing of the diffractive features (i.e., the grating pitch) that varies across an extent or length of the chirped diffraction grating. In some embodiments, the chirped diffraction grating may have or exhibit a chirp of the diffractive feature spacing that varies linearly with distance. As such, the chirped diffraction grating is a ‘linearly chirped’ diffraction grating, by definition. In other embodiments, the chirped diffraction grating of the multiview pixel may exhibit a non-linear chirp of the diffractive feature spacing. Various non-linear chirps may be used including, but not limited to, an exponential chirp, a logarithmic chirp or a chirp that varies in another, substantially non-uniform or random but still monotonic manner. Non-monotonic chirps such as, but not limited to, a sinusoidal chirp or a triangle or sawtooth chirp, may also be employed. Combinations of any of these types of chirps may also be employed. 
     In other embodiments, diffraction grating  130  configured to provide the directional light beams  102  is or comprises a plurality of diffraction gratings (e.g., sub-gratings). For example, the plurality of diffraction gratings of the diffraction grating  130  may comprise a first diffraction grating configured to provide a red portion of the directional light beams  102 . Further, the plurality of diffraction gratings of the diffraction grating  130  may comprise a second diffraction grating configured to provide a green portion of the directional light beams  102 . Further still, the plurality of diffraction gratings of the diffraction grating  130  may comprise a third diffraction grating configured to provide a blue portion of the directional light beams  102 . In some embodiments, individual diffraction gratings of the plurality of diffraction gratings may be superimposed on one another. In other embodiments, the diffraction gratings may be separate diffraction gratings arranged next to one another, e.g., as an array. 
     More generally, the multicolor static multiview display  100  may comprise one or more instances of multiview pixels  140 , which each comprise sets of diffraction gratings  130  from the plurality of diffraction gratings  130 . As shown in  FIG.  7 B , the diffraction gratings  130  of the set that makes up a multiview pixel  140  may have different grating characteristics. The diffraction gratings  130  of the multiview pixel may have different grating orientations, for example. In particular, the diffraction gratings  130  of the multiview pixel  140  may have different grating characteristics determined or dictated by a corresponding set of views of a color multiview image. For example, the multiview pixel  140  may include a set of eight (8) diffraction gratings  130  that, in turn, correspond to 8 different views of the multicolor static multiview display  100 . Moreover, the multicolor static multiview display  100  may include multiple multiview pixels  140 . For example, there may be a plurality of multiview pixels  140  with sets of diffraction gratings  130 , each multiview pixels  140  corresponding to a different one of 2048×1024 pixels in each of the 8 different views. 
     In some embodiments, multicolor static multiview display  100  may be transparent or substantially transparent. In particular, the light guide  110  and the spaced apart plurality of diffraction gratings  130  may allow light to pass through the light guide  110  in a direction that is orthogonal to both the first surface  110 ′ and the second surface  110 ″, in some embodiments. Thus, the light guide  110  and more generally the multicolor static multiview display  100  may be transparent to light propagating in the direction orthogonal to the general propagation direction  103  of the guided light beams  112  of the guided light beam plurality. Further, the transparency may be facilitated, at least in part, by the substantially transparency of the diffraction gratings  130 . 
     In accordance with some embodiments of the principles described herein, a multiview display is provided. The multiview display is configured to emit a plurality of directional light beams provided by the multiview display. Further, the emitted directional light beams may be preferentially directed toward a plurality of views zones of the multiview display based on the grating characteristics of a plurality of diffraction grating that are included in one or more multiview pixels in the multiview display. Moreover, the diffraction gratings may produce different principal angular directions in the directional light beams, which corresponding to different viewing directions for different views in a set of views of the color multiview image of the multicolor multiview display. In some examples, the multicolor multiview display is configured to provide or ‘display’ a color 3D or multiview image. Different ones of the directional light beams may correspond to individual view pixels of different ‘views’ associated with the color multiview image, according to various examples. The different views may provide a ‘glasses free’ (e.g., autostereoscopic) representation of information in the color multiview image being displayed by the multicolor multiview display, for example. 
       FIG.  8    illustrates a block diagram of a multicolor static multiview display  200  in an example, according to an embodiment consistent with the principles described herein. According to various embodiments, the multicolor static multiview display  200  is configured to display a color multiview image according to different views in different view directions. In particular, a plurality of directional light beams  202  emitted by the multicolor static multiview display  200  are used to display the color multiview image and may correspond to color pixels of the different views (i.e., color view pixels). The directional light beams  202  are illustrated as arrows emanating from one or more multiview pixels  210  in  FIG.  8   . Also illustrated in  FIG.  8    are a first view  14 ′, a second view  14 ″, and a third view  14 ″′, of a color multiview image  16  that may be provided by the multicolor static multiview display  200 . 
     Note that the directional light beams  202  associated with one of multiview pixels  210  are either static or quasi-static (i.e., not actively modulated). Instead, the multiview pixels  210  either provide the directional light beams  202  when they are illuminated or do not provide the directional light beams  202  when they are not illuminated. Further, an intensity of the provided directional light beams  202  along with a direction of those directional light beams  202  defines the pixels of the color multiview image  16  being displayed by the multicolor static multiview display  200 , while a color of the directional light beams  202  is determined by a selectable color of the multicolor static multiview display  200 , according to various embodiments. The displayed views  14 ′,  14 ″,  14 ″′ within the color multiview image  16  may be static or quasi-static, according to various embodiments. 
     The multicolor static multiview display  200  illustrated in  FIG.  8    comprises an array of the multiview pixels  210 . The multiview pixels  210  of the array are configured to provide a plurality of different views of the multicolor static multiview display  200 . According to various embodiments, a multiview pixel  210  of the array comprises a plurality of diffraction gratings  212  configured to diffractively couple out or emit the plurality of directional light beams  202 . The plurality of directional light beams  202  may have principal angular directions, which correspond to different views directions of different views in a set of views of the multicolor static multiview display  200 . Moreover, grating characteristics of the diffraction gratings  212  may be varied or selected based on the radial direction of incident light beams to diffraction gratings  212 , a distance to a light source that provides the incident light beams or both. In some embodiments, the diffraction gratings  212  and multiview pixels  210  may be substantially similar to diffraction gratings  130  and multiview pixel  140 , respectively, of the multicolor static multiview display  100 , described above. 
     As illustrated in  FIG.  8   , the multicolor static multiview display  200  further comprises a light guide  220  configured to guide light. In some embodiments, the light guide  220  may be substantially similar to the light guide  110  described above with respect to the multicolor static multiview display  100 . According to various embodiments, the multiview pixels  210 , or more particularly the diffraction gratings  212  of the various multiview pixels  210 , are configured to scatter or couple out a portion of guided light (or equivalently ‘guided light beams  204 ’, as illustrated) from the light guide  220  as the plurality of directional light beams  202  (i.e., the guided light may be the incident light beams discussed above). In particular, the multiview pixels  210  are optically connected to the light guide  220  to scatter or couple out the portion of the guided light (i.e., guided light beams  204 ) by diffractive scattering or diffractive coupling. 
     In various embodiments, grating characteristics of the diffraction gratings  212  are varied based on or as a function of a radial direction of incident guided light beams  204  at the diffraction gratings  212 , a distance between a light source that provides the guided light beams  204 , or both. In this way, the directional light beams  202  from different diffraction gratings  212  in a multiview pixel may correspond to pixels of views of a color multiview image provided by the multicolor static multiview display  200 . 
     The multicolor static multiview display  200  illustrated in  FIG.  8    further comprises a multicolor light source  230 . The multicolor light source  230  may be configured to provide the light to the light guide  110 . In particular, the provided light (e.g., illustrated by arrows emanating from the multicolor light source  230  in  FIG.  8   ) is guided by the light guide  110  as a plurality of guided light beams  204 . The guided light beams  204  of the guided light beam plurality comprise a selectable color (i.e., the selectable color of the multicolor static multiview display  200 ) and have different radial directions from one another within the light guide  220 , according to various embodiments. In some embodiments, the guided light beams  204  are provided with a non-zero propagation angle and, in some embodiments, having a collimation factor to provide a predetermined angular spread of the guided light beams  204  within the light guide  220 , for example. According to some embodiments, the multicolor light source  230  may be substantially similar to one of the multicolor light source(s)  120  of the multicolor static multiview display  100 , described above. For example, the multicolor light source  230  may be butt-coupled to an input edge of the light guide  220 . The multicolor light source  230  may radiate light in a fan-shape or radial pattern to provide the plurality of guided light beams  204  having the different radial directions. Further, the multicolor light source  230  may comprise a plurality of different color optical emitters interlaced with one another within the multicolor light source. The selectable color may be a combination of different colors of light provided by the different color optical emitter plurality, for example. 
     In accordance with other embodiments of the principles described herein, a method of multicolor static multiview display operation is provided.  FIG.  9    illustrates a flow chart of a method  300  of multicolor static multiview display operation in an example, according to an embodiment consistent with the principles described herein. The method  300  of multicolor static multiview display operation may be used to provide one or both display of a color static multiview image and display of a color quasi-static multiview image, according to various embodiments. 
     As illustrated in  FIG.  9   , the method  300  of multicolor static multiview display operation comprises guiding  310  the light along the light guide as a plurality of guided light beams comprising a selectable color, the guided light beams of the guided light beam plurality having a common point of origin and different radial directions from one another. In particular, a guided light beam of the guided light beam plurality has, by definition, the selectable color. In addition, by definition, the guided light beam has a different radial direction of propagation from another guided light beam of the guided light beam plurality. Further, each of the guided light beams of the guided light beam plurality has, by definition, a common point of origin. The point of origin may be a virtual point of origin (e.g., a point beyond an actual point of origin of the guided light beam), in some embodiments. For example, the point of origin may be outside of the light guide and thus be a virtual point of origin. According to some embodiments, the light guide along which the light is guided  310  as well as the guided light beams comprising the selectable color that are guided therein may be substantially similar to the light guide  110  and guided light beams  112 , respectively, as described above with reference to the multicolor static multiview display  100 . 
     The method  300  of multicolor static multiview display operation illustrated in  FIG.  9    further comprises emitting  320  a plurality of directional light beams representing a color multiview image using a plurality of diffraction gratings. According to various embodiments, a diffraction grating of the diffraction grating plurality diffractively couples or scatters out light from the guided light beam plurality as a directional light beam of the directional light beam plurality. Further, the directional light beam that is coupled or scattered out has both an intensity and a principal angular direction of a corresponding view pixel of the color multiview image. In particular, the plurality of directional light beams produced by the emitting  320  may have principal angular directions corresponding to different view pixels in a set of views of the color multiview image. Moreover, intensities of directional light beams of the directional light beam plurality may correspond to intensities of various view pixels of the color multiview image. In some embodiments, each of the diffraction gratings produces a single directional light beam in a single principal angular direction and having a single intensity corresponding to a particular view pixel in one view of the color multiview image. A color of the directional light beam is determined by the selectable color. In some embodiments, the diffraction grating comprises a plurality of diffraction grating (e.g., sub-gratings). Further, a set of diffraction gratings may be arranged as a multiview pixel of the multicolor static multiview display, in some embodiments. 
     In various embodiments, the intensity and principal angular direction of the emitted  320  directional light beams are controlled by a grating characteristic of the diffraction grating that is based on (i.e., is a function of) a location of the diffraction grating relative to the common origin point. In particular, grating characteristics of the plurality of diffraction gratings may be varied based on, or equivalently may be a function of, radial directions of incident guided light beams at the diffraction gratings, a distance from the diffraction gratings to a multicolor light source that provides the guided light beams, or both. 
     According to some embodiments, the plurality of diffraction gratings may be substantially similar to the plurality of diffraction gratings  130  of the multicolor static multiview display  100 , described above. Further, in some embodiments, the emitted  320  plurality of directional light beams may be substantially similar to the plurality of directional light beams  102 , also described above. For example, the grating characteristic controlling the principal angular direction may comprise one or both of a grating pitch and a grating orientation of the diffraction grating. Further, an intensity of the directional light beam provided by the diffraction grating and corresponding to an intensity of a corresponding view pixel may be determined by a diffractive coupling efficiency of the diffraction grating. That is, the grating characteristic controlling the intensity may comprise a grating depth of the diffraction grating, a size of the gratings, etc., in some examples. 
     As illustrated, the method  300  of multicolor static multiview display operation further comprises providing  330  light to be guided as the plurality of guided light beams using a multicolor light source. In particular, light is provided to the light guide as the guided light beams comprising the selectable color and having a plurality of different radial directions of propagation using the multicolor light source. According to various embodiments, the multicolor light source used in providing  330  light is located at a side of the light guide, the multicolor light source location being the common origin point of the guided light beam plurality. In some embodiments, the multicolor light source may be substantially similar to the multicolor light source(s)  120  of the multicolor static multiview display  100 , described above. 
     In particular, the multicolor light source may be butt-coupled to an edge or side of the light guide. Further, the multicolor light source may approximate a point source representing the common point of origin, in some embodiments. In addition, in some embodiments, providing  330  light to be guided as the plurality of guided light beams using a multicolor light source comprising a plurality of different color optical emitters interlaced with one another within the multicolor light source. 
     In some embodiments (not illustrated), the method  300  of multicolor static multiview display operation further comprises combining colors of light provided  330  by the plurality of different color optical emitters to produce the selectable color. The colors of light may comprise red light, blue light and green light. The selectable color produced by combining colors may be substantially any color (e.g., according to an RGB color model). 
     In some embodiments (not illustrated), the method  300  of multicolor static multiview display operation further comprises animating the color multiview image by guiding a first plurality of light guided light beams during a first time period and guiding a second plurality of guided light beams during a second time period during a second period. The first guided light beam plurality may have a common origin point that differs from a common origin point of the second guided light beam plurality. For example, the light source may comprise a plurality of laterally offset light sources, e.g., configured to provide animation, as described above. Animation may comprise a shift in an apparent location of the color multiview image during the first and second time periods, according to some embodiments. In some embodiments, the selectable color may be changed between different predefined colors a part of or during animating. 
     Thus, there have been described examples and embodiments of a multicolor static multiview display and a method of multicolor static multiview display operation having diffraction gratings configured to provide a plurality of directional light beams representing a color static or quasi-static multiview image from guided light beams having different radial directions from one another. 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. Clearly, those skilled in the art can readily devise numerous other arrangements without departing from the scope as defined by the following claims.