Patent Description:
<CIT> describes a head-tracking multiview display and a head-tracking multiview display system selectively provide a primary set of views and a secondary view representing a perspective view of a scene that is angularly adjacent to the primary view set. <CIT> describes a autostereoscopic three-dimensional image display apparatus having a modified sub-pixel structure. <CIT> describes a device for displaying a multi-view 3D image by using viewing zone expansion that is applicable to multiple observers. <CIT> describes a multi view display which is arranged to provide large viewing zones and includes a barrier comprising a plurality of color portions that co-operate with color filters in a display panel to selectively direct light to the viewing zones.

Certain embodiments are defined in the dependent claims.

Examples and embodiments in accordance with the principles described herein provide a multiview display employing dynamic color sub-pixel remapping. In various embodiments consistent with the principles herein, a multiview display is provided. The multiview display is configured to shift a location of a multiview pixel relative to a location of color sub-pixels as a function of a position of a user of the multiview display. The shift provides dynamic color sub-pixel shifting or remapping that may mitigate color fringing on the multiview display, according to some embodiments.

Herein a `two-dimensional display' or `2D display' is defined as a display configured to provide a view of an image that is substantially the same regardless of a direction from which the image is viewed (i.e., within a predefined viewing angle or viewing range of the 2D display). A liquid crystal display (LCD) found in may smart phones and computer monitors are examples of 2D displays. In contrast herein, a `multiview display' is defined as an electronic display or display system configured to provide different views of a 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 multiview image. In some instances, a multiview display may also be referred to as a three-dimensional (3D) display, e.g., when simultaneously viewing two different views of the multiview image provides a perception of viewing a three-dimensional image (3D image).

<FIG> illustrates a perspective view of a multiview display <NUM> in an example, according to an embodiment consistent with the principles described herein. As illustrated in <FIG>, the multiview display <NUM> comprises a screen <NUM> to display a multiview image to be viewed. The multiview display <NUM> provides different views <NUM> of the multiview image in different view directions <NUM> relative to the screen <NUM>. The view directions <NUM> are illustrated as arrows extending from the screen <NUM> in various different principal angular directions; the different views <NUM> are illustrated as shaded polygonal boxes at the termination of the arrows (i.e., depicting the view directions <NUM>); and only four views <NUM> and four view directions <NUM> are illustrated, all by way of example and not limitation. Note that while the different views <NUM> are illustrated in <FIG> as being above the screen, the views <NUM> actually appear on or in a vicinity of the screen <NUM> when the multiview image is displayed on the multiview display <NUM>. Depicting the views <NUM> above the screen <NUM> is only for simplicity of illustration and is meant to represent viewing the multiview display <NUM> from a respective one of the view directions <NUM> corresponding to a particular view <NUM>.

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> illustrates a graphical representation of the angular components {θ, ϕ} of a light beam <NUM> having a particular principal angular direction corresponding to a view direction (e.g., view direction <NUM> in <FIG>) of a multiview display in an example, according to an embodiment consistent with the principles described herein. In addition, the light beam <NUM> is emitted or emanates from a particular point, by definition herein. That is, by definition, the light beam <NUM> has a central ray associated with a particular point of origin within the multiview display. <FIG> 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 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).

A `multiview pixel' is defined herein as a set of pixels representing 'view' pixels in each of a similar plurality of different views of a multiview display. In particular, a multiview pixel may have an individual pixel or set of pixels corresponding to or representing a view pixel in each of the different views of the multiview image. By definition herein therefore, a `view pixel' is a pixel or set of pixels corresponding to a view in a multiview pixel of a multiview display. In some embodiments, a view pixel may include one or more color sub-pixels. 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 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 located at {x1, y1} in each of the different views of a multiview image, while a second multiview pixel may have individual view pixels located at {x2, y2} in each of the different views, and so on.

In some embodiments, a number of 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 sixty-four (<NUM>) view pixels associated with a multiview display having <NUM> different views. In another example, the multiview display may provide an eight by four array of views (i.e., <NUM> views) and the multiview pixel may include thirty-two (<NUM>) view pixels (i.e., one for each view). Additionally, each different view pixel may have an associated direction (e.g., light beam principal angular direction) that corresponds to a different one of the view directions corresponding to the <NUM> different views, for example. Further, according to some embodiments, a number of multiview pixels of the multiview display may be substantially equal to a number of view pixels (i.e., pixels that make up a selected view) in the multiview display views each view of the multiview display. For example, if a view includes six hundred forty by four hundred eighty view pixels (i.e., a <NUM> x <NUM> view resolution), the multiview display may have three hundred seven thousand two hundred (<NUM>,<NUM>) multiview pixels. In another example, when the views include one hundred by one hundred pixels, the multiview display may include a total of ten thousand (i.e., <NUM> x <NUM> = <NUM>,<NUM>) multiview pixels.

By definition herein, a `multibeam emitter' is a structure or element of a backlight or a display that produces light that includes a plurality of light beams. In some embodiments, the multibeam emitter may be optically coupled to a light guide of a backlight to provide the light beams by coupling out a portion of light guided in the light guide. In such embodiments, a multibeam emitter may comprise a `multibeam element. ' In other embodiments, the multibeam emitter may generate light emitted as the light beams (i.e., may comprise a light source). Further, the light beams of the plurality of light beams produced by a multibeam emitter have different principal angular directions from one another, by definition herein. In particular, by definition, a light beam of the plurality has a predetermined principal angular direction that is different from another light beam of the light beam plurality. Furthermore, the light beam plurality may represent a light field. For example, the light beam plurality may be confined to a substantially conical region of space or have a predetermined angular spread that includes the different principal angular directions of the light beams in the light beam plurality. As such, the predetermined angular spread of the light beams in combination (i.e., the light beam plurality) may represent the light field. According to various embodiments, the different principal angular directions of the various light beams are determined by a characteristic including, but not limited to, a size (e.g., length, width, area, etc.) of the multibeam emitter. In some embodiments, the multibeam emitter may be considered an `extended point light source', i.e., a plurality of point light sources distributed across an extent of the multibeam emitter, by definition herein. Further, a light beam produced by the multibeam emitter has a principal angular direction given by angular components {θ, φ}, by definition herein, and as described above with respect to <FIG>.

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. 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.

By definition, 'broad-angle' emitted light is defined as light having a cone angle that is greater than a cone angle of the view of a multiview image or multiview display. In particular, in some embodiments, the broad-angle emitted light may have a cone angle that is greater than about twenty degrees (e.g., > ± <NUM>°). In other embodiments, the broad-angle emitted light cone angle may be greater than about thirty degrees (e.g., > ± <NUM>°), or greater than about forty degrees (e.g., > ± <NUM>°), or greater than fifty degrees (e.g., > ± <NUM>°). For example, the cone angle of the broad-angle emitted light may be about sixty degrees (e.g., > ± <NUM>°).

In some embodiments, the broad-angle emitted light cone angle may be defined to be about the same as a viewing angle of an LCD computer monitor, an LCD tablet, an LCD television, or a similar digital display device meant for broad-angle viewing (e.g., about ± <NUM>-<NUM>°). In other embodiments, broad-angle emitted light may also be characterized or described as diffuse light, substantially diffuse light, non-directional light (i.e., lacking any specific or defined directionality), or as light having a single or substantially uniform direction.

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 color sub-pixel' means one or more color sub-pixels and as such, 'the color sub-pixel' means `color sub-pixel(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 <NUM>%, or plus or minus <NUM>%, or plus or minus <NUM>%, 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 <NUM>% to about <NUM>%. 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 that provides dynamic color sub-pixel remapping. <FIG> illustrates a cross-sectional view of a multiview display <NUM> in an example, according to an embodiment consistent with the principles described herein. <FIG> illustrates a plan view of the multiview display <NUM> in an example, according to an embodiment consistent with the principles described herein. <FIG> illustrates a plan view of a portion of the multiview display <NUM> of <FIG> in an example, according to an embodiment consistent with the principles described herein. According to various embodiments, the multiview display <NUM> illustrated in <FIG> may employ dynamic color sub-pixel remapping to mitigate color fringing in or associated with a multiview image displayed by or on the multiview display <NUM>.

The multiview display <NUM> comprises an array of light valves <NUM>. <FIG> also illustrate light valves <NUM> of the light valve array arranged as a plurality of multiview pixels <NUM>, outlined by dashed lines in <FIG>. According to various embodiments, the light valve array may comprise any of a variety of different types of light valves including, but not limited to, a liquid crystal light valve, an electrophoretic light valve, and a light valve based on electrowetting.

As illustrated in <FIG> and <FIG>, the array of light valves <NUM> comprises a repeating plurality of color sub-pixels <NUM> configured to modulate directional light beams as color pixels of different views of a multiview image displayed on or by the multiview display <NUM>. In particular, each light valve <NUM> of the light valve array includes the plurality of color sub-pixels <NUM>. As such, across the light valve array the plurality of color sub-pixels <NUM> repeats from one light valve <NUM> to an adjacent light valve <NUM> as the repeating color sub-pixel plurality.

In some embodiments, as illustrated in <FIG>, a light valve <NUM> of the array of light valves <NUM> may comprise the plurality of color sub-pixels <NUM> having a first color sub-pixel <NUM>-<NUM>, a second color sub-pixel <NUM>-<NUM>, and a third color sub-pixel <NUM>-<NUM>. Further, as illustrated in <FIG>, the plurality of color sub-pixels <NUM> may be the same in each light valve <NUM> of the light valve array. As a result, the color sub-pixel plurality having the first, second, and third color sub-pixels <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> may repeat across the light valve array (e.g., in a row direction), according to various embodiments.

In some embodiments, a color sub-pixel <NUM> of the repeating color sub-pixel plurality may have or represent a different color from another color sub-pixel of the repeating color sub-pixel plurality (e.g., each color sub-pixel <NUM> may include a different color filter representing a different color). For example, the first color sub-pixel <NUM>-<NUM> may be a red color sub-pixel (R), the second color sub-pixel <NUM>-<NUM> may be a green color sub-pixel (G), and the third color sub-pixel <NUM>-<NUM> may be a blue color sub-pixel (B), e.g., as illustrated in <FIG>. Since the color sub-pixel plurality repeats along a row of the array of light valves <NUM>, the repeating color sub-pixel plurality comprises a repeating set of red (R), green (G), and blue (B) color sub-pixels <NUM>, as illustrated in <FIG> by way of example and not limitation. The repeating set of red (R), green (G), and blue (B) color sub-pixels <NUM> may be consistent with a red-green-blue (RGB) color model used to display color multiview images with the multiview display <NUM>, according to some embodiments. In other non-limiting examples and embodiments (not illustrated), the repeating plurality of color sub-pixels <NUM> may include, but is not limited to, a repeating set that includes red (R), green (G), and blue (B), and yellow (Y) color sub-pixels <NUM> (RGBY) and a repeating set that includes red (R), green (G), and blue (B), and white (W) color sub-pixels <NUM> (RGBW).

As illustrated on <FIG> (and discussed above), light valve array with the repeating plurality of color sub-pixels <NUM> is arranged as a plurality of multiview pixels <NUM> of the multiview display <NUM>. Each multiview pixel of the plurality of multiview pixels <NUM> comprises a different subset of the repeating plurality of color sub-pixels <NUM>. Each multiview pixel <NUM> is configured to modulate directional light beams as color pixels of different views of the multiview display <NUM>. The modulated light beams represent the respective different colors of the color sub-pixels <NUM> of the color sub-pixel plurality within the color pixels of the multiview display <NUM>. Further, individual light valves <NUM> within each multiview pixel <NUM> of the multiview pixel plurality represent different ones of the different views of the multiview image or equivalently of the multiview display <NUM>, according to various embodiments.

By way of example and not limitation, the multiview display <NUM> illustrated in <FIG> includes multiview pixels <NUM> representing a four-by-four (<NUM> x <NUM>) arrangement of different views. That is, the illustrated multiview display <NUM> has multiview pixels <NUM> configured to provide sixteen (<NUM>) different views in a full parallax mode. Accordingly, each multiview pixel <NUM> of the plurality includes sixteen (<NUM>) light valves <NUM>, each light valve comprising three (<NUM>) color sub-pixels <NUM>, as illustrated. In particular, as illustrated each light valves <NUM> comprises a set of three consecutive color sub-pixels <NUM> including a red (R) color sub-pixel <NUM>, a green (G) color sub-pixel <NUM>, and a blue (B) color sub-pixel <NUM>. The plurality of multiview pixels <NUM> may be arranged in rows and columns of multiview pixels <NUM> (e.g., as illustrated), according to some embodiments.

According to various embodiments, a location of a multiview pixel <NUM> of the multiview pixel plurality relative to a location of color sub-pixels <NUM> of the light valve array is configured to be shifted as a function of a position of a user <NUM> of the multiview display <NUM>. The shift may provide dynamic color sub-pixel remapping of or with respect to multiview pixels <NUM> of the multiview display <NUM>. According to some embodiments, the dynamic color sub-pixel remapping may mitigate color fringing within a multiview image displayed on the multiview display <NUM> when the user <NUM> views the multiview image from the position used to determine the shift.

<FIG> illustrates a plan view of a portion of a multiview display <NUM> in an example, according to an embodiment consistent with the principles described herein. As illustrated in <FIG>, a multiview pixel <NUM> spans from a red (R) color sub-pixel <NUM> at an upper left corner to a blue (B) color sub-pixel <NUM> at a lower right corner of the multiview pixel <NUM>. Further, a first view V1 may correspond to a first set of three color sub-pixels <NUM> (R, G, B) at the upper left corner, a second view V2 may correspond to a second set of three color sub-pixels <NUM> (R, G, B) adjacent and to the right of the first set, and a third view V3 may correspond to a third set of three color sub-pixels <NUM> (R, G, B) adjacent and to the right of the second set, as illustrated.

When the user <NUM> views the multiview display <NUM> from a location centered on view V2, the user <NUM> will experience a multiview image that is free of color fringing. That is, the views V1, V2, V3 will be color balanced when the location of the user <NUM> is centered on view V2 along the repeating plurality of color sub-pixels <NUM>, i.e., along a row. In <FIG>, an arrow indicates a line of sight of the user <NUM> viewing the multiview display <NUM>. Accordingly, the line of sight of the user <NUM> is aligned with the center of view V2 (or the second set of color sub-pixels <NUM>) of the multiview pixel <NUM>. Since the user <NUM> is aligned with the center of view V2 (or the multiview pixel <NUM>), the user <NUM> will experience a color-balanced view of view V2 or more generally of the multiview image. However, if the user <NUM> were to move to slightly to the right or left, the user <NUM> may experience a multiview image that lacks color balance or that includes color fringing. For example, view V2 may include a bluish artifact, while view V3 may include a red ghost or artifact when viewed by the user <NUM>.

<FIG> illustrates plan view of a portion of the multiview display <NUM> of <FIG> in another example, according to an embodiment consistent with the principles described herein. In particular, the multiview display <NUM> is the same multiview display <NUM> illustrated in <FIG>. However, <FIG> illustrates the user <NUM> at a new location that is to the right such that, while the user <NUM> may continue to observe the view V2, the line of sight of the user has moved with the user to be aligned with a color sub-pixel <NUM> that is off center of view V2 or the multiview pixel <NUM>, as originally illustrated in <FIG>. Since the line of sight of the user <NUM> is off center, the multiview image may lack color balance if the original multiview pixel <NUM> of <FIG> were to be used.

However, <FIG> illustrates a multiview pixel <NUM>' having a location that is shifted relative to the color sub-pixels <NUM> as a function of the new user location. Accordingly, the multiview pixel <NUM>' is shifted to a new location such that the multiview pixel <NUM>' spans from a green (G) color sub-pixel <NUM> (of view V1) at an upper left corner to a red (R) color sub-pixel <NUM> (of view '<NUM>') at a lower right corner of the multiview pixel <NUM>'. Further, after the shift, the first view V1 corresponds to a first set of three color sub-pixels <NUM> (G, B, R) at the upper left corner, a second view V2 corresponds to a second set of three color sub-pixels <NUM> (G, B, R) adjacent and to the right of the first set, and the third view V3 corresponds to a third set of three color sub-pixels <NUM> (G, B, R) adjacent and to the right of the second set, as illustrated in <FIG>. Each of the three views V1, V2, V3 still have a full complement of color sub-pixels <NUM>, but the color balance is restored by the shift of the multiview pixel <NUM> relative to the color sub-pixels <NUM> of the light valve array. As with <FIG>, an arrow indicates a line of sight of the user <NUM> viewing the multiview display <NUM> in <FIG>.

According to some embodiments, a shift distance of the multiview pixel location may be an integer multiple of a size of a color sub-pixel <NUM> of the repeating color sub-pixel plurality. For example, in <FIG> the multiview pixel <NUM>' is shifted by a width of one (<NUM>) color sub-pixel <NUM> in a row direction of the repeating plurality of color sub-pixels <NUM> in response to the movement in location of the user <NUM>, compared to the position of the multiview pixel <NUM> in <FIG> prior to the movement. In other embodiments (not illustrated), the shift distance may amount to two widths, three widths, and so on, of a color sub-pixel <NUM>, for example, As a result, the multiview pixel <NUM> is remapped to a different set of color sub-pixels <NUM> of the repeating plurality of color sub-pixels <NUM> to reposition the line of sight of the user <NUM> on the center of multiview pixel <NUM> or more specifically to a center of the second set of color sub-pixels <NUM> corresponding to view V2. In doing so, a different set of color sub-pixels <NUM> form the multiview pixel <NUM>' in <FIG> as compared to the multiview pixel <NUM> of <FIG>. Thus, whereas the multiview pixel <NUM> of <FIG> spanned from the red (R) color sub-pixel <NUM> to a blue (B) color sub-pixel <NUM> along a first row of the repeating plurality of color sub-pixels <NUM>, the multiview pixel <NUM>' illustrated in <FIG> spans from the green (G) color sub-pixel <NUM> to a red (R) color sub-pixel <NUM> along the same repeating plurality of color sub-pixels <NUM>. Correspondingly, view V2 of the multiview pixel <NUM> is shifted from the set of color sub-pixels <NUM> (R, G, B) in <FIG> to the different set of color sub-pixels <NUM> (G B, R) in <FIG>, which re-centers view V2 on the line of sight of the user <NUM>. All other views in the multiview pixel <NUM>' are similarly shifted in the same direction along the repeating plurality of color sub-pixels <NUM>, by the shift. Further, the shift is a row direction of the light valve array, as illustrated in <FIG>.

According to various embodiments, the shift of the multiview pixel <NUM>, <NUM>' in response to change in a location by the user <NUM> may be performed while the multiview display <NUM> is active and displaying the multiview image. Accordingly, remapping of the color sub-pixels <NUM> performed with the shift of the multiview pixel location may be accomplished dynamically. Herein, therefore, dynamic sub-pixel remapping is defined as the reassignment of at least one color sub-pixel <NUM> to a different multiview pixel <NUM> while the multiview display <NUM> is active. The dynamic color sub-pixel remapping of the multiview display <NUM> is configured to mitigate color fringing associated with the color pixels of the multiview image. In particular, the shift of the multiview pixels <NUM> help minimize uneven overlap between directional light beams <NUM> of different colors that can emphasize certain colors in a pixel over other colors, depending on the position and view point of the user <NUM>.

Referring again to <FIG>, the illustrated multiview display <NUM> further comprises an array of multibeam emitters <NUM>. The multibeam emitters <NUM> are configured to provide the directional light beams <NUM> modulated by the plurality of color sub-pixels <NUM> of the light valve array. The directional light beams <NUM> may have principal angular directions corresponding to respective different view directions of the multiview display <NUM> or equivalently of different views of the multiview image displayed on or by the multiview display <NUM>. In particular, <FIG> illustrates the directional light beams <NUM> as a plurality of diverging arrows depicted as being directed way from the multibeam emitters <NUM> in a direction toward the light valve array.

In some embodiments, a size of the multibeam emitter <NUM> is comparable to a size of a light valve <NUM> of the multiview display <NUM>. Herein, the 'size' may be defined in any of a variety of manners to include, but not be limited to, a length, a width or an area. For example, the size of a light valve <NUM> may be a length thereof and the comparable size of the multibeam emitter <NUM> may also be a length of the multibeam emitter <NUM>. In another example, size may refer to an area such that an area of the multibeam emitter <NUM> may be comparable to an area of the light valve <NUM>. In some embodiments, the size of the multibeam emitter <NUM> is comparable to the light valve size such that the multibeam emitter size is between about fifty percent (<NUM>%) and about two hundred percent (<NUM>%) of the light valve size.

In some embodiments, the multiview display <NUM> may comprise a light guide <NUM>, e.g., as illustrated. The light guide <NUM> is configured to guide light along a length of the light guide as guided light <NUM> (i.e., a guided light beam <NUM>). For example, the light guide <NUM> 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 <NUM> according to one or more guided modes of the light guide <NUM>, for example.

In some embodiments, the light guide <NUM> may be a slab or plate of an optical waveguide (i.e., a plate light guide) 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 <NUM> using total internal reflection. According to various examples, the optically transparent material of the light guide <NUM> 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 <NUM> may further include a cladding layer (not illustrated) on at least a portion of a surface (e.g., one or both of the first surface and the second surface) of the light guide <NUM>. The cladding layer may be used to further facilitate total internal reflection, according to some examples.

Further, according to some embodiments, the light guide <NUM> is configured to guide the guided light <NUM> according to total internal reflection at a non-zero propagation angle between a first surface <NUM>' (e.g., front or top surface or side) and a second surface <NUM>" (e.g., back or bottom surface or side) of the light guide <NUM>. In particular, the guided light <NUM> propagates by reflecting or 'bouncing' between the first surface <NUM>' and the second surface <NUM>" of the light guide <NUM> at the non-zero propagation angle. In some embodiments, the guided light <NUM> comprises a plurality of guided light beams having different colors of light from one another and being guided by the light guide <NUM> at respective ones of different color-specific, non-zero propagation angles. Note, the non-zero propagation angle is not illustrated in <FIG> for simplicity of illustration. However, a bold arrow depicting a propagation direction <NUM> illustrates a general propagation direction of the guided light <NUM> along the light guide length in <FIG>.

According to some embodiments, the multibeam emitters <NUM> of the array may be located at or adjacent to the first surface <NUM>' of the light guide <NUM>, for example, as illustrated in <FIG>. In other embodiments (not illustrated), the plurality of multibeam emitters <NUM> may be located on a second surface <NUM>" of the light guide <NUM>. In yet other embodiments (not illustrated), the multibeam emitters <NUM> of the plurality may be located inside the light guide <NUM> between the first surface <NUM>' and the second surface <NUM>". Further, in yet other embodiments (not illustrated), the light guide <NUM> may be replaced by another substrate (e.g., a non light guide substrate).

In some embodiments (e.g., embodiments that employ the light guide <NUM> as in <FIG>), the multibeam emitter <NUM> of the multiview display <NUM> may comprise a multibeam element <NUM>'. The multibeam element <NUM>' of the multiview display <NUM> is configured to scatter out light from the light guide <NUM> as a plurality of directional light beams having principal angular directions corresponding to view directions of the multiview image. According to various embodiments, the multibeam element <NUM>' may comprise any of a number of different structures configured to scatter out a portion of the guided light <NUM>. For 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 <NUM>' comprising a diffraction grating is configured to diffractively scatter out the guided light portion as the plurality of directional light beams having the different principal angular directions. In other embodiments, the multibeam element <NUM>' comprising a micro-reflective element is configured to reflectively scatter out the guided light portion as the plurality of directional light beams, or the multibeam element <NUM>' comprising a micro-refractive element is configured to scatter out the guided light portion as the plurality of directional light beams by or using refraction (i.e., refractively scatter out the guided light portion).

Further in embodiments that employ the light guide <NUM>, the multiview display <NUM> may further comprise a light source <NUM> configured to provide the light to be guided within light guide <NUM>. In particular, the light source <NUM> may be located adjacent to an entrance surface or end (input end) of the light guide <NUM>. In various embodiments, the light source <NUM> may comprise substantially any source of light (e.g., optical emitter) including, but not limited to, one or more light emitting diodes (LEDs) or a laser (e.g., laser diode). In some embodiments, the light source <NUM> may comprise an optical emitter configured produce a substantially monochromatic light having a narrowband spectrum denoted by a particular color. In particular, the color of the monochromatic light may be a primary color of a particular color space or color model (e.g., a red-green-blue (RGB) color model). In other examples, the light source <NUM> may be a substantially broadband light source configured to provide substantially broadband or polychromatic light. For example, the light source <NUM> may provide white light. In some embodiments, the light source <NUM> may comprise a plurality of different 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.

In some embodiments, the guided light <NUM> may be collimated or equivalently may be a collimated light beam (e.g., provided by a collimator, as described below). 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 confined to a predetermined or defined angular spread within the light beam (e.g., the guided light <NUM>). 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, the guided light <NUM> may be collimated according to or having a collimation factor σ, in various embodiments.

In other embodiments (not illustrated), the multibeam emitters <NUM> may comprise an active emitter such as, but not limited to, a micro light emitting diode and a micro organic light emitting diode. In these embodiments, the light guide and light source may be omitted. Instead, the light guide <NUM> may be replaced by a substrate to support and provide power to the multibeam emitters <NUM>, as mentioned above.

In some embodiments, the multiview display <NUM> further comprises a broad-angle backlight <NUM> adjacent to the light guide <NUM>. <FIG> illustrates a cross-sectional view of a multiview display <NUM> comprising a broad-angle backlight <NUM> in an example, according to an embodiment of the principles described herein. The broad-angle backlight <NUM> is opposite to a side of the light guide <NUM> adjacent to the light valve array. In the embodiment illustrated, the broad-angle backlight <NUM> is adjacent to a bottom surface <NUM>" of the light guide <NUM>. The broad-angle backlight <NUM> is configured to provide or emit broad-angle light <NUM>.

The light guide <NUM> and the array of multibeam elements <NUM>' may be configured to be optically transparent to the broad-angle light <NUM> emitted from the adjacent broad-angle backlight <NUM>. Thus, broad-angle light <NUM> may be emitted from the broad-angle backlight <NUM> and through a thickness of light guide <NUM>. The broad-angle light <NUM> from the broad-angle backlight <NUM> is therefore received through the bottom surface <NUM>" of the light guide <NUM>, transmitted through a thickness of the light guide <NUM>, and emitted from the array of light valves <NUM>. Because the light guide <NUM> is optically transparent to the broad-angle light <NUM>, the broad-angle light <NUM> is not substantially affected by the light guide <NUM>.

The multiview display <NUM> of <FIG> may selectively operate in a two-dimensional (2D) mode or a multiview mode (MULTIVIEW). In the 2D mode, the multiview display <NUM> is configured to emit the broad-angle light <NUM> provided by the broad-angle backlight <NUM>. In the multiview mode, the multiview display <NUM> is configured to emit the directional light beams <NUM>, as previously described. The combination of the light guide <NUM> and broad-angle backlight <NUM> may be used in dual (2D/3D) display, for example.

In some embodiments (not illustrated), a user tracker may be employed with the multiview display <NUM> as part of a multiview display system. According to various embodiments, the user tracker is configured to track a location or a position of the user <NUM> relative to the multiview display <NUM> to provide the user position. In particular, the user tracker may be configured to track a position of the user <NUM> (e.g., of a head of the user) in a region in front of the multiview display <NUM>, that is, a region adjacent to a light emitting surface or an image view screen of the multiview display <NUM>.

According to various embodiments, any of a variety of devices, systems and circuits that provide user tracking (or equivalently tracking of a position of the user) may be employed as the user tracker of the multiview display system. The user tracker may thus comprise a position sensor. For example, in some embodiments, the user tracker comprising a position sensor may comprise a camera configured to capture an image of the user relative to the screen of the multiview display <NUM>. Further, the user tracker may comprise an image processor (or general purpose computer programmed as an image processor) configured to determine a position of the user within the captured image relative to the screen of the multiview display <NUM>. The user position relative to the screen of the multiview display <NUM> may be determined from the captured image by the image processor using various techniques including, but not limited to, image recognition or pattern matching, for example. Further, the user tracker may comprise a motion sensor. The user tracker comprising a motion sensor may comprise one or both of a hardware-based motion sensor and a software-based motion sensor. The hardware-based motion sensors may comprise a gyroscope, an accelerometer, a magnetometer, or a geomagnetic sensor, for example. Software-based sensors may comprise one or more of a gravity sensor, a linear acceleration sensor, a rotation vector sensor, and a step detector (e.g., a 'significant' motion sensor, a step counter, etc.). The hardware-based and software-based motion sensors are configured to track a relative motion of the multiview display <NUM>. The motion of the user relative to the multiview display <NUM> may be used to infer a position of the user with respect to the multiview display <NUM>. In some embodiments, the user tracker may comprise both position sensor and a motion sensor.

In accordance with some embodiments of the principles described herein, a multiview display system <NUM> is provided. <FIG> illustrates a block diagram of a multiview display system <NUM> in an example, according to an embodiment consistent with the principles herein. The multiview display system <NUM> comprises a multibeam backlight <NUM>. The multibeam backlight <NUM> is configured to provide emitted light as a plurality of directional light beams <NUM> having principal angular directions corresponding to respective view directions of the multiview display. The multibeam backlight <NUM> may be shaped as a 'slab' or substantially flat block of substrate comprising two substantially parallel and opposite planar surfaces (i.e., a top and a bottom surface).

The multiview display system <NUM> further comprises an array of light valves <NUM> having a repeating plurality of color sub-pixels. The light valves of the array are substantially similar to the light valves <NUM> of the multiview display <NUM>, previously described. As such, different types of light valves may be employed as the light valves <NUM> of the light valve array including, but not limited to, one or more of liquid crystal light valves, electrophoretic light valves, and light valves based on electrowetting. In some embodiments, each color sub-pixel of the repeating plurality of color sub-pixels has a different color. For example, the repeating plurality of color sub-pixels may consist of a repeating set of red (R), green (G), and blue (B) color sub-pixels (RGB) in this order along a row of the array of light valves <NUM>. In other embodiments, the repeating plurality of color sub-pixels may comprise a repeating set of red (R), green (G), blue (B), and yellow (Y) color sub-pixels (RGBY). In yet another embodiment, the repeating set may include red (R), green (G), blue (B), and white (W) pixels (RGBW). The light valves <NUM> of the light valve array are arranged as multiview pixels <NUM> configured to modulate the directional light beams <NUM> as color pixels of views of a multiview image.

The multiview display system <NUM> further comprises a user tracker <NUM> configured to track a position of a user relative to the multiview display. The user tracker <NUM> may comprise a position sensor. For example, the user tracker comprising a motion sensor may comprise a camera to capture an image of the user relative to the screen of the multiview display system <NUM>. The user tracker <NUM> comprising a motion sensor may further comprise a processor configured to determine a position of the user within the captured image relative to the screen of the multiview display system <NUM>. The position of the user relative to the screen of the multiview display system <NUM> may thus be determined from the captured image. Further, the user tracker <NUM> may comprise a motion sensor configured to track a relative motion of the multiview display system <NUM>. The motion of the user relative to the multiview display system <NUM> may be used to infer a position of the user with respect to the multiview display system <NUM>. In some embodiments, the user tracker <NUM> may comprise both a position sensor and a motion sensor. In some embodiments, the user tracker <NUM> may be substantially similar to the user tracker described above with respect to multiview display <NUM>.

According to various embodiments, locations of the multiview pixels <NUM> relative to locations of color sub-pixels of the light valve array are configured to be shifted as a function of the tracked user position to provide dynamic color sub-pixel remapping. In some embodiments, the dynamic color sub-pixel remapping may be substantially similar to the dynamic color sub-pixel remapping of the above-described multiview display <NUM>, e.g., as illustrated in and described with respect to <FIG> and <FIG>. In particular, in response to the user moving in position relative to the multiview display system <NUM>, one or more multiview pixels <NUM> may be remapped to a different set of color sub-pixels of the repeating plurality of color sub-pixels of the array of light valves <NUM>. The shift may be replicated for all multiview pixels <NUM> of the multiview display system <NUM>, and a different set of color sub-pixels forms each multiview pixel <NUM>, e.g., as in <FIG>. In various examples, the multiview pixels <NUM> are shifted in the direction of the plurality of color sub-pixels to follow the tracked position of the user in order to maintain the color balance in the view aligned with the user position.

In some embodiments, the shift distance of the multiview pixel location is an integer multiple of a size of a color sub-pixel of the color sub-pixel plurality. For example, the multiview pixels <NUM> may be shifted by a distance about equal to a width of one of the color sub-pixels of the light valve array, e.g., as illustrated in <FIG> and <FIG>. In other embodiments, the shift distance may be about equal to two times a color sub-pixel width, three times a color sub-pixel width, and so on, for example.

In some embodiments, the multibeam backlight <NUM> comprises a plurality of multibeam emitters <NUM> distributed across the multibeam backlight. Multibeam emitters <NUM> of the plurality may be substantially similar to the multibeam emitters <NUM> described above with respect to the multiview display <NUM>. In particular, multibeam emitters <NUM> of the multibeam emitter plurality are configured to provide directional light beams <NUM> of the directional light beam plurality of the light emitted by the multiview display system <NUM>. The multibeam emitters <NUM> of the plurality may be located on a surface of or within the multibeam backlight <NUM>, according to various embodiments.

In some embodiments (not illustrated), the multibeam backlight <NUM> further comprises a light guide. The light guide is configured to guide light in a propagation direction along a length of the light guide as guided light. The light guide may be substantially similar to the light guide <NUM> of the above-described multiview display <NUM>, in some embodiments. According to various embodiments, the light guide may be configured to guide the guided light using total internal reflection. Further, the guided light may be guided at a non-zero propagation angle by or within the light guide. In some embodiments, the guided light may be collimated or may be a collimated light beam. In particular, the guided light may be collimated according to or having a collimation factor σ, in various embodiments.

In some embodiments, a multibeam emitter of the plurality of multibeam emitters <NUM> comprises a multibeam element. In some embodiments, the multibeam element may be substantially similar to the multibeam element <NUM>' described above. The multibeam element is configured to scatter out a portion of the guided light as the directional light beams <NUM> of the multiview display system <NUM>. According to various embodiments, the multibeam element may be located on a surface of or within the light guide.

In some embodiments, a size of the multibeam emitter <NUM> or the element is comparable to a size of a light valve <NUM> of the light valve array. In some embodiments, the size of the multibeam emitter or element is comparable to the light valve size such that the multibeam element size is between about fifty percent (<NUM>%) and about two hundred percent (<NUM>%) of the light valve size.

In some embodiments, the multibeam element may comprise any of a number of different structures configured to scatter out a portion of the guided light. For 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 comprising a diffraction grating is configured to diffractively scatter out the guided light portion as the plurality of directional light beams having the different principal angular directions. In other embodiments, the multibeam element comprising a micro-reflective element is configured to reflectively scatter out the guided light portion as the plurality of directional light beams, or the multibeam element comprising a micro-refractive element is configured to scatter out the guided light portion as the plurality of directional light beams by or using refraction (i.e., refractively scatter out the guided light portion).

In accordance with some embodiments of the principles described herein, a method <NUM> of multiview display system operation is provided. <FIG> illustrates a flowchart of a method <NUM> of a multiview display system operation in an example, according to an embodiment consistent with the principles described herein. The method <NUM> of multiview display system operation comprises modulating <NUM> directional light beams using an array of light valves having a repeating plurality of color sub-pixels. The array of light valves may be substantially similar to the array of light valves <NUM> described above with respect to the multiview display <NUM>. As such, different types of light valves may be employed as the light valves of the light valve array including, but not limited to, one or more of liquid crystal light valves, electrophoretic light valves, and light valves based on electrowetting. In some embodiments, each color sub-pixel of the repeating plurality of color sub-pixels has a different color. For example, the repeating plurality of color sub-pixels may consist of a repeating set of red (R), green (G), and blue (B) color sub-pixels (RGB) in this order along a row of the array of light valves. The repeating plurality of color sub-pixels is arranged as a plurality of multiview pixels to provide color pixels of views of a multiview image, according to various embodiments.

The method <NUM> further comprises tracking <NUM> a position of a user relative to the multiview display system with a user-tracking module to provide a tracked position of the user. In some embodiments, the user-tracking module may be substantially similar to the user tracker <NUM> of the multiview display system <NUM>, described above. For example, the user-tracking module may comprise a position sensor configured to provide a position of the user relative to the multiview display system. Further, the user-tracking module may comprise a motion sensor configured to track a relative motion of the multiview display. The motion the user relative to the multiview display system may be used to infer a position of the user with respect to the multiview display system, for example. In some embodiments, the user-tracking module may comprise both a position sensor and a motion sensor.

As illustrated in <FIG>, the method <NUM> further comprises shifting <NUM> a location of a multiview pixel of the multiview pixel plurality relative to a location of color sub-pixels of the light valve array as a function of the tracked user position to provide dynamic color sub-pixel remapping and mitigate color fringing perceived by the user when viewing the multiview display. In some embodiments, shifting <NUM> may be substantially similar to the shift as previously described with respect to either the multiview display <NUM> or multiview display system <NUM>. In some embodiments, the shifting <NUM> changes the location of the multiview pixel by an integer multiple of a size of a color sub-pixel in a row direction of the color sub-pixels.

In some embodiments, the method <NUM> further comprises emitting the directional light beams using an array of multibeam emitters. The multibeam emitters of the array may be substantially similar to the multibeam emitters <NUM> of the multiview display <NUM>, as described above. In some embodiments, emitting the directional light beams comprises guiding light in a light guide as guided light. The light guide may be substantially similar to the light guide <NUM> of the multiview display <NUM>, and light may be guided at a non-zero propagation angle between opposite internal surfaces of the light guide. In some embodiments, the multibeam emitters of the multibeam emitter array may be multibeam elements of a multibeam element array, each multibeam element corresponding to a different multibeam emitter of the multibeam emitter array. With the multibeam emitter array being an array of multibeam elements, emitting the directional light beams using the array of multibeam emitters may further comprise scattering out a portion of the guided light from the light guide using a multibeam element of the multibeam element array to provide the directional light beams. The multibeam element may be substantially similar to the multibeam element <NUM>' of the multiview display <NUM>. Further, the multibeam emitter or the multibeam element may have a size comparable to a size of a light valve of the light valve array. For example, the size of the multibeam emitter or multibeam element may be comparable to the light valve size such that the multibeam element size is between about fifty percent (<NUM>%) and about two hundred percent (<NUM>%) of the light valve size.

In some embodiments, tracking a position of a user relative to the multiview display system comprises monitoring a relative motion of the multiview display system using a motion sensor to infer the user position from the relative motion. In some embodiments, wherein tracking a position of a user relative to the multiview display system comprises tracking the user position with a position sensor. In some embodiments, tracking a user position comprises both monitoring the relative motion using a motion sensor and tracking the user position with a position sensor. According to various embodiments, the motion sensor may comprise, but is not limited to, one or both of a gyroscope and an accelerometer. In some embodiment, the position sensor may comprise, but is not limited to, one or more of a capacitive sensor, a camera, and a time-of-flight sensor.

Claim 1:
A multiview display system (<NUM>, <NUM>) comprising:
a multibeam backlight (<NUM>) configured to provide emitted light as a plurality of directional light beams (<NUM>) having different principal angular directions corresponding to respective different view directions of the multiview display, the multiview display configured to provide different views of a multiview image to the different view directions,
an array of light valves (<NUM>,<NUM>) having a repeating plurality of color sub-pixels (<NUM>) and arranged as multiview pixels (<NUM>) configured to modulate the directional light beams as color pixels of the views of the multiview image; and
a user tracker (<NUM>) configured to track a position of a user relative to the multiview display,
wherein locations of the multiview pixels relative to locations of color sub-pixels of the light valve array are configured to be shifted as a function of the tracked user position to provide dynamic color sub-pixel remapping.