HK1242785B - Three-dimensional (3d) electronic display - Google Patents

Description

Three-dimensional (3D) electronic display

Cross Reference to Related Applications

Not applicable.

Statement regarding federally sponsored research or development

Not applicable.

Background

Electronic displays are a nearly ubiquitous medium for conveying information to users of a wide variety of devices and products. The most common electronic displays include Cathode Ray Tubes (CRTs), Plasma Display Panels (PDPs), Liquid Crystal Displays (LCDs), electroluminescent displays (ELs), Organic Light Emitting Diodes (OLEDs) and active matrix OLEDs (amoleds) displays, electrophoretic displays (EPs) and various displays employing electromechanical or galvanic light modulation (e.g., digital micromirror devices, electrowetting displays, etc.). Generally, electronic displays can be classified as either active displays (i.e., displays that emit light) or passive displays (i.e., displays that modulate light provided by another source). The most obvious examples of active displays are CRTs, PDPs and OLEDs/AMOLEDs. Generally classified as passive displays when considering emitted light are LCD and EP displays. Passive displays often have attractive performance characteristics including, but not limited to, inherently low power consumption, but may find some limited use in many practical applications due to the lack of ability to emit light.

To overcome the limitations of passive displays associated with emitting light, many passive displays are coupled to an external light source. The coupled light sources may allow these otherwise passive displays to emit light and actually function as active displays. An example of such a coupled light source is a backlight. Backlights are light sources (typically plate light sources) that are placed behind an otherwise passive display to illuminate the passive display. For example, the backlight may be coupled to an LCD or EP display. The backlight emits light through the LCD or EP display screen. The emitted light is modulated by the LCD or EP display and then the modulated light is emitted from the LCD or EP display. The backlight is typically configured to emit white light. The white light is then converted to the various colors used in the display using color filters. For example, a color filter may be placed between the output (less common) or backlight of an LCD or EP display and the LCD or EP display.

Drawings

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

fig. 1A illustrates a cross-sectional view of a three-dimensional (3D) electronic display in an example according to an embodiment consistent with principles described herein.

Fig. 1B illustrates a cross-sectional view of a three-dimensional (3D) electronic display in an example according to another embodiment consistent with principles described herein.

Fig. 1C illustrates a plan view of a three-dimensional (3D) electronic display in an example according to an embodiment consistent with principles described herein.

Figure 2 illustrates a perspective view of a rectangular multibeam diffraction grating in an example, according to an embodiment consistent with principles described herein.

Fig. 3A illustrates a block diagram of a three-dimensional (3D) color electronic display in an example according to an embodiment consistent with principles described herein.

Fig. 3B illustrates a cross-sectional view of a three-dimensional (3D) color electronic display in an example according to an embodiment consistent with principles described herein.

Fig. 4 illustrates a flow chart of a method of three-dimensional (3D) electronic display operation in an example according to an embodiment consistent with the principles described herein.

Fig. 5 illustrates a flow chart of a method of three-dimensional (3D) color electronic display operation in an example according to an embodiment consistent with the principles described herein.

Certain examples and embodiments have additional features in addition to, or instead of, those shown in the above-described reference figures. These and other features are described in detail below with reference to the above-referenced figures.

Detailed Description

An embodiment in accordance with the principles described herein provides for the display of three-dimensional (3D) data. According to an embodiment of the principles described herein, a three-dimensional (3D) electronic display with enhanced perceptual resolution is provided. In other embodiments, a 3D color electronic display is provided that employs color filter equipped light valves to facilitate spatially multiplexed color reproduction of 3D information. The 3D electronic displays (both monochrome and color) provided by the various embodiments described herein can be used to display images and information in conjunction with so-called "glasses-free" or autostereoscopic display systems.

Herein, a "light guide" is defined as a structure that uses total internal reflection to guide light within the structure. In particular, the light guide may comprise a core that is substantially transparent at the operating wavelength of the light guide. In various examples, a "light guide" generally refers to a dielectric optical waveguide that employs total internal reflection to guide light at an interface between the dielectric material of the light guide and the material or medium surrounding the light guide. By definition, the condition for total internal reflection is that the refractive index of the light guide is greater than the refractive index of the surrounding medium adjacent to the surface of the light guide material. In some examples, the light guide may include a coating in addition to or in lieu of the aforementioned refractive index differences to further promote total internal reflection. For example, the coating may be a reflective coating. According to various examples, the light guide may be any of several light guides, including but not limited to one or both of a plate or guide plate and a guide strip.

Further, herein, the term "plate" as in "plate light guide" is defined as a segmented or differential planar layer or sheet (i.e., plate) when applied to a light guide. In particular, a plate light guide is defined as a light guide configured to guide light in two substantially orthogonal directions defined by a top surface and a bottom surface (i.e., opposing surfaces) of the light guide. Further, by definition herein, both the top and bottom surfaces are separated from each other and may be substantially parallel to each other, at least in terms of differences. That is, the top and bottom surfaces are substantially parallel or coplanar in any differentially small region of the plate light guide. In some examples, the plate light guide may be substantially flat (e.g., defined as a plane), and thus the plate light guide is a planar light guide. In other examples, 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 plate light guide. However, in various examples, any curvature has a radius of curvature large enough to ensure that total internal reflection is maintained in the plate light guide to guide the light.

According to various examples described herein, a diffraction grating (e.g., a multibeam diffraction grating) may be used to scatter or couple light out of a plate light guide. Herein, a "diffraction grating" is generally defined as a plurality of features (i.e., diffractive features) arranged to provide diffraction of light incident on the diffraction grating. In some examples, the plurality of features may be arranged in a periodic or quasi-periodic manner. For example, a diffraction grating may include a plurality of features (e.g., a plurality of grooves in a surface of a material) arranged in a one-dimensional (1-D) array. In other examples, the diffraction grating may be a two-dimensional (2-D) array of features. For example, the diffraction grating may be a 2-D array of projections or holes on the surface of the material.

Thus, a "diffraction grating" is a structure that provides diffraction of light incident on the diffraction grating, according to the definitions herein. If light is incident on the diffraction grating from the light guide, the diffraction or diffractive scattering provided may result in and is therefore referred to as "diffractive coupling" because the diffraction grating may couple light out of the light guide by diffraction. Diffraction gratings also redirect or change the angle of light by diffraction (i.e., at a diffraction angle). In particular, as a result of diffraction, light that exits the diffraction grating (i.e., diffracted light) typically has a propagation direction that is different from the propagation direction of light incident on the diffraction grating (i.e., incident light). Changing the direction of propagation of light by diffraction is referred to herein as "diffractive redirection". Thus, a diffraction grating may be understood as a structure comprising diffractive features that diffractively redirect light incident on the diffraction grating, and if the light is incident from a light guide, the diffraction grating may also diffractively couple out light from the light guide.

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

A "multibeam diffraction grating," as defined herein, is a diffraction grating that produces a light beam comprising a plurality of light beams that produces diffractively redirected or outcoupled light. Further, the plurality of light beams produced by the multibeam diffraction grating have principal angular directions that are different from one another, as defined herein. In particular, by definition, a light beam of the plurality of light beams has a predetermined principal angular direction that is different from other light beams of the plurality of light beams due to diffractive coupling and diffractive redirection of incident light by the multibeam diffraction grating. For example, the plurality of main light beams may comprise eight light beams having eight different main angular directions. For example, the combined eight light beams (i.e., the plurality of light beams) may represent a light field. According to various examples, the different principal angular directions of the various light beams are determined by a combination of the orientation or rotation and the spacing or pitch of the diffractive features of the multibeam diffraction grating at the origin of the respective light beams from the multibeam diffraction grating relative to the direction of propagation of the light incident on the multibeam diffraction grating.

According to various embodiments described herein, a multibeam diffraction grating is employed to couple light out of a plate light guide, e.g., as a pixel of an electronic display. In particular, a plate light guide having a multibeam diffraction grating to produce a plurality of light beams having different angular directions may be part of a backlight of or used with an electronic display, such as, but not limited to, a "glasses-free" three-dimensional (3D) electronic display (e.g., also known as a multiview or "holographic" electronic display or an autostereoscopic display). Thus, the differently oriented light beams produced by coupling out the guided light from the light guide using the multibeam diffraction grating may be or represent "pixels" of a 3D electronic display.

Herein, a "light source" is defined as a source of light (e.g., a device or apparatus that generates and emits light). For example, the light source may be a Light Emitting Diode (LED) that emits light when activated. Herein, the light source may be virtually any light source or light emitting source, 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 light emitter, a fluorescent lamp, an incandescent lamp, and virtually any other light source. The light generated by the light source may have a color (i.e., may include a particular wavelength of light), or may be a range of wavelengths. In particular, different colored light sources or light emitters may produce substantially monochromatic light of different wavelengths from one another, as defined herein.

In addition, as used herein, the articles "a" and "an" are intended to have their ordinary meaning in the patent arts, i.e., "one or more". For example, "a grating" refers to one or more gratings, and thus "grating" refers herein to "grating(s)". Further, references herein to "top," "bottom," "above," "below," "upper," "lower," "front," "back," "first," "second," "left," or "right" are not intended as limitations herein. Herein, unless expressly stated otherwise, the term "about" when applied to a value generally means within the tolerance of the equipment used to produce the value, or in some examples, means plus or minus 10%, or plus or minus 5%, or plus or minus 1%. Further, the term "substantially" as used herein means, for example, a majority, or almost all, or an amount in the range of about 51% to about 100%. Furthermore, the examples herein are intended to be illustrative only and are for purposes of discussion and not for limitation.

According to various embodiments of the principles described herein, a three-dimensional (3D) electronic display is provided. Fig. 1A illustrates a cross-sectional view of a three-dimensional (3D) electronic display 100 in an example according to an embodiment consistent with principles described herein. Fig. 1B illustrates a cross-sectional view of a three-dimensional (3D) electronic display 100 in an example according to another embodiment consistent with principles described herein. Fig. 1C illustrates a plan view of a three-dimensional (3D) electronic display 100 in an example, according to an embodiment consistent with principles described herein. For example, the 3D electronic display 100 shown in fig. 1C may represent the 3D electronic display 100 shown in either of fig. 1A or 1B. According to various embodiments, the 3D electronic display 100 may provide an enhanced perceived resolution (e.g., not a physical or actual resolution) to represent or display the 3D information.

In particular, the 3D electronic display 100 is configured to produce modulated "directional" light, i.e. light comprising light beams with different principal angular directions. For example, as shown in fig. 1A and 1B, the 3D electronic display 100 may provide or generate a plurality of light beams 102 directed out of and away from the 3D electronic display 100 along different predetermined principal angular directions (e.g., as a light field). Conversely, the plurality of light beams 102 may be modulated in order to display information having 3D content. In some examples, modulated light beams 102 having different predetermined principal angular directions form a plurality of pixels of the 3D electronic display 100. Furthermore, the 3D electronic display 100 may be a so-called "glasses-free" 3D electronic display (e.g., one multi-view, "holographic," or autostereoscopic display), in which the beams 102 correspond to pixels associated with different "views" of the 3D electronic display 100. According to various embodiments, the perception of the resolution of the displayed 3D information may be enhanced relative to the original "pixel resolution" of the plurality of pixels of the 3D electronic display 100.

According to various examples, the light beam 102 may form a light field in a viewing direction of the 3D electronic display 100. According to some embodiments, a light beam 102 of the plurality of light beams 102 (and within the light field) may be configured to have a different principal angular direction than other light beams 102 of the plurality of light beams. Further, according to various embodiments, in addition to light beam 102 having a predetermined or principal angular direction, light beam 102 may have a relatively narrow angular spread within the light field. As such, the principal angular direction of the light beam 102 may correspond to the angular direction of a particular view of the 3D electronic display 100. Further, according to some embodiments, the light beams 102, and more particularly the modulated light beams 102, may represent or correspond to pixels (e.g., dynamic pixels) of the 3D electronic display 100 that correspond to a particular view direction.

As shown in fig. 1A, 1B, and 1C, the 3D electronic display 100 includes a light guide 110. In particular, according to some embodiments, the light guide 110 may be a plate light guide 110. The light guide 110 is configured to guide light from a light source (not shown in fig. 1A-1C) as guided light 104. 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. For example, the difference in refractive indices is configured to facilitate total internal reflection of the guided light 104 according to one or more guiding modes of the light guide 110.

In some embodiments, light from the light source is directed along the length of the light guide 110 as a beam of light 104. Further, the light guide 110 may be configured to guide light (i.e., the guided light beam 104) at a non-zero propagation angle. For example, the guided light beam 104 may be guided within the light guide 110 at a non-zero propagation angle using total internal reflection.

As defined herein, a "non-zero propagation angle" is an angle relative to a surface (e.g., a top or bottom surface) of the light guide 110. In some examples, the non-zero propagation angle of the guided light beam 104 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.

In some examples, light from the light source is introduced or coupled into the light guide 110 at a non-zero propagation angle (e.g., about 30-35 degrees). For example, one or more of a lens, mirror, or similar reflector (e.g., a tilted collimating reflector) and a prism (not shown) may facilitate coupling light into the input end of the plate light guide 110 as a light beam at a non-zero propagation angle. Once coupled into the light guide 110, the guided light beam 104 propagates along the plate light guide 110 in a direction generally away from the input end (e.g., as shown by the thick arrow along the x-axis in FIGS. 1A-1B). Further, the guided light beam 104 propagates by reflecting or "bouncing" (e.g., illustrated by an extended angled arrow representing a ray of guided light 104) between the top and bottom surfaces of the plate light guide 110 at a non-zero propagation angle.

Further, according to various examples, the guided light beam 104 produced by coupling light into the light guide 110 may be a collimated light beam. In particular, by "collimated light beam", it is meant that the rays within the guided light beam 104 are substantially parallel to each other within the guided light beam 104. Light rays that diverge or are scattered from the collimated beam of the guided light beam 104, as defined herein, are not considered part of the collimated beam. For example, collimation for producing light that collimates the guided light beam 104 may be provided by a lens or mirror (e.g., a tilted collimating reflector, etc.) for coupling the light into the plate light guide 110.

In some examples, the plate light guide 110 may be a sheet or plate light guide that includes an extended, substantially planar, optically transparent dielectric material. The substantially flat piece of dielectric material is configured to guide the guided light beam 104 using total internal reflection. According to various examples, the optically transparent material of plate light guide 110 can include or be made of any of a variety of dielectric materials, including, but not limited to, one or more of various types of glass (e.g., quartz glass, alkali aluminosilicate glass, borosilicate glass, etc.) and virtually optically transparent plastics or polymers (e.g., poly (methyl methacrylate) or "acrylic glass", polycarbonate, etc.). In some examples, the plate light guide 110 may further include a cladding layer on at least a portion of a surface (e.g., one or both of the top surface and the bottom surface) of the plate light guide 110 (not shown). According to some examples, cladding layers may be used to further promote total internal reflection.

In fig. 1A, 1B, and 1C, the illustrated 3D electronic display 100 also includes an array of multibeam diffraction gratings 120 arranged in a plurality of offset rows (see, e.g., fig. 1C). In some examples, an array of multibeam diffraction gratings 120 is located on a surface of the plate light guide 110. For example, the multibeam diffraction grating 120 may be located on a top or front surface of the plate light guide 110, as shown in fig. 1A-1B. In other examples (not shown), the multibeam diffraction grating 120 may be located within the plate light guide 110. In combination, the plate light guide 110 and the array of multibeam diffraction gratings 120 provide or function as a backlight (i.e., a diffraction grating-based backlight) for the 3D electronic display 100.

According to various embodiments, the array of multibeam diffraction gratings 120 is configured to diffractively couple out a portion of the guided light beam 104 as a plurality of light beams having different principal angular directions corresponding to different views of the 3D electronic display 100. In particular, portions of the guided light beam 104 are coupled out of the plate light guide 110 by or using diffractive coupling (e.g., also referred to as "diffractive scattering"). For example, a portion of the guided light beam 104 may be diffractively coupled out by the multibeam diffraction grating 120 through a light guide surface (e.g., through a top surface of the light guide 110). Further, the multibeam diffraction grating 120 is configured to diffractively couple out a portion of the guided light beam 104 as a coupled-out light beam (e.g., the light beam 102), and diffractively redirect the coupled-out light beam 102 away from the plate light guide surface as the plurality of light beams 102. As described above, each shot 102 in the plurality of beams has a different predetermined principal angular direction. For example, according to various examples, light beams 102 of the plurality of light beams may be directed out of a plate light guide surface at, within, or on (e.g., adjacent to) a location at which multibeam diffraction grating 120 is located.

In general, according to various embodiments, the light beam 102 of the plurality of light beams produced by the multibeam diffraction grating 120 may be divergent (e.g., as shown) or convergent (not shown). In particular, fig. 1A and 1B show a beam 102 of a plurality of diverging beams. The diverging or converging beam 102 is determined by the direction of propagation of the guided light beam 104 relative to the characteristics of the multibeam diffraction grating 120 (e.g., the "chirp" direction, as described below). In some examples where the light beam 102 diverges, the diverging light beam 102 may exhibit divergence from a "virtual" point (not shown) located a distance below or behind the multibeam diffraction grating 120. Similarly, according to some examples, the converging light beams may converge or intersect at a virtual point (not shown) above or in front of the multibeam diffraction grating 120 (e.g., the top or front surface of the plate light guide).

According to various embodiments, the multibeam diffraction grating 120 of the array includes a plurality of diffractive features 122 (shown, for example, in fig. 1A and 1B) that provide diffraction. The provided diffraction is responsible for diffractively coupling a portion of the guided light beam 104 out of the plate light guide 110. For example, the multibeam diffraction grating 120 may include one or both of grooves in a surface of the plate light guide 110 and ridges protruding from the plate light guide surface as diffractive features 122. The grooves and ridges may be arranged parallel to each other and perpendicular to the direction of propagation of the guided light beam 104, which is coupled out by the multibeam diffraction grating 120, at least at some point along the diffractive feature 122.

In some examples, grooves or ridges may be etched, ground, or molded into the plate light guide surface. Thus, the material of the multibeam diffraction grating 120 may comprise the material of the plate light guide 110. For example, as shown in fig. 1B, the multibeam diffraction grating 120 includes substantially parallel ridges protruding from a surface of the plate light guide 110. In fig. 1A, multibeam diffraction grating 120 includes substantially parallel grooves 122 that penetrate the surface of plate light guide 110. In other examples (not shown), multibeam diffraction grating 120 may be applied or fixed to a light guide surface.

According to some embodiments, multibeam diffraction grating 120 may be or include a chirped diffraction grating. By definition, a "chirped" diffraction grating is a diffraction grating exhibiting or having diffraction intervals of diffractive features 122 that vary over the range or length of the chirped diffraction grating, for example, as shown in figures 1A-1B. The varying diffraction spacing is referred to herein as "chirp". As a result of the chirp, the portion of the guided light beam 104 that is diffractively coupled out of the plate light guide 110 exits or is emitted from the chirped diffraction grating 120 as the coupled-out light beam 102 passes through the chirped diffraction grating of the multibeam diffraction grating 120 at different diffraction angles corresponding to different origins. With a predefined chirp, the chirped diffraction grating is responsible for a predetermined and different principal angular direction of the coupled-out light beam 102 of the plurality of light beams.

In some examples, the chirped diffraction grating of the multibeam diffraction grating 120 may have or exhibit a chirp of the diffraction spacing that varies linearly with distance. Accordingly, the chirped diffraction grating may be referred to as a "linearly chirped" diffraction grating. For example, fig. 1A-1B illustrate multibeam diffraction grating 120 as a linearly chirped diffraction grating. In particular, as shown, the diffractive features 122 are closer together at a first end than at a second end of the multibeam diffraction grating 120. Further, the diffraction spacing of the diffractive features 122 shown varies linearly from the first end to the second end.

In another example (not shown), the chirped diffraction grating 120 of the multibeam diffraction grating 120 may exhibit a nonlinear chirp of the diffraction interval d. Various non-linear chirps that may be used to implement the multibeam diffraction grating 120 include, but are not limited to, an exponential chirp, a logarithmic chirp, or a chirp that varies in another manner that is substantially non-uniform or random, but still monotonic. Non-monotonic chirps may also be used, such as but not limited to sinusoidal chirps or triangular or saw-tooth chirps. Combinations of any of these types of chirps may also be employed.

In some examples, as described above, the light beam 102 generated by coupling the guided light beam 104 out of the plate light guide 110 using the multibeam diffraction grating 120 may diverge (i.e., the diverging light beam 102), for example, when the guided light beam 104 propagates in a direction from a first end to a second end of the multibeam diffraction grating 120 (e.g., as shown in fig. 1A-1B). Alternatively, according to other examples, the converging light beam 102 may be produced when the guided light beam 104 propagates from the second end to the first end of the multi-beam diffraction grating 120 (not shown). In particular, according to various embodiments, whether the beam 102 diverges or converges may be determined by the chirp direction relative to the direction of the guided beam.

According to some embodiments, the multibeam diffraction grating 120 may include diffractive features 122 that are one or both of curved and chirped. Furthermore, according to some embodiments, multibeam diffraction grating 120 may have a substantially rectangular shape. Figure 2 illustrates a perspective view of a rectangular multibeam diffraction grating 120 in an example, according to an embodiment consistent with principles described herein. The multibeam diffraction grating 120 shown in fig. 2 includes curved and chirped diffractive features 122 (e.g., grooves or ridges) at, in, or on the surface of the plate light guide 110 (i.e., the multibeam diffraction grating 120 is a curved chirped diffraction grating). In fig. 2, the guided light beam 104 has an incident direction with respect to the multibeam diffraction grating 120, as indicated by the thick arrow 104. Also shown is a multibeam diffraction grating 120 with a plurality of coupled-out or emitted light beams 102 directed away from a surface of the plate light guide 110. As shown, the light beam 102 is emitted in a plurality of predetermined different principal angular directions. In particular, as shown, the predetermined different principal angular directions of the emitted light beam 102 differ in both azimuth and elevation. According to various examples, both the predetermined chirp of the diffractive feature 122 and the curvature of the diffractive feature 122 may be responsible for predetermined different main angular directions of the emitted light beam 102.

Referring again to fig. 1C, the array of multibeam diffraction gratings 120 may be arranged at, on, or in a surface of the plate light guide 110 in various configurations, according to various embodiments. In particular, as shown in fig. 1C, the multibeam diffraction grating 120 of the array is a component of a plurality of gratings arranged in rows and columns across the light guide surface. For example, the rows and columns of the multibeam diffraction grating array may represent a rectangular array. Further, as described above, the array of multibeam diffraction gratings 120 includes rows that are offset from each other (i.e., offset rows). Offset the offset between rows is generally defined herein as the "row direction" as the direction along the rows (e.g., "x-direction" oriented along the x-axis). According to various examples, the offset and spacing between adjacent rows of the multibeam diffraction grating array may facilitate producing a 3D electronic display with enhanced perceptual resolution.

For example, a first row (i.e., a first offset row) of the multibeam diffraction gratings 120 in the array may be offset in a row direction or an x-direction of the offset row relative to a second row (i.e., a second offset row) of the multibeam diffraction gratings 120 in the array adjacent to the first row. In some embodiments, the offset between the first and second rows (e.g., adjacent rows) may be about half the spacing between the beam diffraction gratings 120 in each row (i.e., 1/2 pitches) in the array (1/2).

Figure 1C shows a first row 124 of the multibeam diffraction grating 120 adjacent to and offset from a second row 126 (e.g., adjacent rows on either side of the first row 124). Further, as shown, the first row 124 is offset from the second row 126 in the row direction (i.e., x-direction) by half (1/2) (i.e., P/2) of the pitch P of the multibeam diffraction grating 120 array. The offset or offset amount or distance in FIG. 1C is labeled "O". FIG. 1C also shows rows having a row direction aligned with the x-direction and an offset direction corresponding to the x-direction. As shown therein, the offset O is one-half the pitch P (1/2).

In other examples (not shown), the offset may include, but is not limited to, one third of the multibeam diffraction grating spacing or pitch (1/3) and one quarter of the pitch (1/4). In some examples (not shown), the offset rows may not be directly adjacent. For example, a first pair of directly adjacent rows (e.g., a first row and a second row) may be substantially aligned with each other, while a second pair of directly adjacent rows (e.g., a third row and a fourth row) may also be substantially aligned with each other. For example, a first pair of aligned immediately adjacent rows may be offset from a second pair of aligned immediately adjacent rows to produce an array of multibeam diffraction gratings 120 arranged in offset rows.

According to some embodiments, the spacing between adjacent rows (e.g., offset rows) of the multibeam diffraction grating 120 is less than the pitch (i.e., the sub-pitch spacing) of the multibeam diffraction grating array. For example, the spacing between adjacent rows may be half the pitch or spacing between multibeam diffraction gratings 120 in a row of the array (1/2). Specifically, fig. 1C shows the first row 124 (i.e., P/2) spaced apart (e.g., spaced apart in the y-direction) from the second row 126 by approximately half (1/2) of the distance P. In fig. 1C, the space between rows is labeled "S" (i.e., S ═ P/2). In other examples (not shown), the spacing between adjacent rows of the multibeam diffraction grating array may be, for example, one-third (1/3), one-fourth (1/4) of the pitch. As defined herein, the spacing between adjacent offset rows is defined as the center-to-center spacing between the multibeam diffraction gratings in a first offset row and the multibeam diffraction gratings in a second offset row, wherein the center-to-center spacing is determined from the center line of each of the first and second offset rows, respectively.

According to various examples, a combination of a row offset of a multibeam diffraction grating array and a sub-pitch spacing between adjacent rows may facilitate producing a 3D electronic display with enhanced perceptual resolution. In particular, spatial subpixel rendering may be used in conjunction with combined offset rows and sub-pitch spacing to provide enhanced perceptual resolution when compared to the native 3D pixel resolution of a 3D electronic display.

Referring to fig. 1A-1C, the 3D electronic display 100 also includes a light valve array 130. According to various embodiments, the light valve array 130 is configured to modulate differently oriented light beams 102 (i.e., a plurality of light beams 102 having different predetermined angular directions) corresponding to different views of the 3D electronic display. In particular, a beam 102 of the plurality of beams passes through and is modulated by a respective light valve 132 of the array of light valves 130. According to various embodiments, the differently oriented light beams 102 that are modulated may represent pixels of a 3D electronic display. In various examples, different types of light valves 132 may be employed in the light valve array 130, including but not limited to one or more of liquid crystal-based light valves, electrophoretic light valves, and electrowetting light valves.

In some embodiments, a subset of the light valves 132 of the light valve array 130 are configured to modulate differently oriented light beams 102 from selected ones of the multibeam diffraction gratings 120 of the multibeam diffraction grating array. This subset is defined herein as a "super-pixel" of the 3D electronic display 100. In these embodiments, each light valve 132 of a super-pixel (or subset) may be configured to modulate a different one of the plurality of differently oriented light beams 102 coupled out by the selected multibeam diffraction grating. For example, in fig. 1A and 1B, a single arrow representing a single light beam 102 is shown passing through a single light valve 132 of the light valve array 130. In addition, the dashed box depicts the example superpixel in FIG. 1C.

In some embodiments (e.g., as shown in fig. 1C), a super-pixel comprises a rectangular arrangement of light valves 132. Furthermore, the rectangular light valve arrangement of the super-pixels is compared to a first direction, which is substantially orthogonal to the second direction. For example, in fig. 1C, there are about half as many light valves 132 in the row direction (e.g., the second or j direction) that is orthogonal to the offset rows of the multibeam diffraction grating array as compared to the row direction (e.g., the first or x direction). As shown in FIG. 1C, by way of example and not limitation, there are four (4) light valves 132 in the j-direction and eight (8) light valves in the x-direction. Note that while having fewer light valves 132 in the second direction may reduce the number of 3D views in that direction when compared to the second direction, such a reduction may be acceptable in many applications of the 3D electronic display 100.

For example, many display applications may benefit from a large number of 3D views in the horizontal direction (e.g., the x-direction). On the other hand, in many applications, a smaller number of 3D views in the vertical direction (e.g., the y-direction) may not significantly degrade, even affecting the ability of the 3D electronic display 100 to exhibit realistic reproduction of 3D information. In particular, the eyes of a user viewing a 3D electronic display are displaced from each other in a horizontal plane (e.g., opposite a vertical plane). Thus, the user is more sensitive to 3D information in the horizontal plane. Embodiments of the 3D electronic display 100 (e.g., as may be provided by the rectangular super-pixels described above) with a larger number of 3D views in the horizontal direction than in the vertical direction can still exhibit high quality 3D information to the user.

According to some examples of the principles described herein, a three-dimensional (3D) color electronic display is provided. Fig. 3A illustrates a block diagram of a three-dimensional (3D) color electronic display 200 in an example according to an embodiment consistent with principles described herein. Fig. 3B illustrates a cross-sectional view of a three-dimensional (3D) color electronic display 200 in an example according to an embodiment consistent with the principles described herein. For example, fig. 3B may illustrate a portion of the 3D color electronic display 200 shown in fig. 3A.

The 3D color electronic display 200 is configured to produce modulated directional light comprising light beams having different principal angular directions and being a plurality of different colors. For example, the 3D color electronic display 200 may provide or generate a plurality of different color beams 202 (e.g., as a field of color light) directed toward and away from the outside of the 3D color electronic display 200 in different predetermined principal angular directions. In turn, the color beams 202 of the plurality of colored light beams may be modulated to facilitate display of information including color.

In some examples, modulated light beams 202 having different predetermined principal angular directions and different colors form a plurality of color pixels of the 3D color electronic display 200. In some examples, 3D color electronic display 200 may be a so-called "glasses-free" 3D color electronic display (e.g., a color multi-view, "holographic" or autostereoscopic display), in which color beams 202 correspond to color pixels associated with different "views" of 3D color electronic display 200. For example, as shown in fig. 3B, a first set of color beams 202' may be oriented in a first direction to represent or correspond to a first view of the 3D color electronic display 200, while a second set of color beams 202 "may be oriented in a second direction to represent or correspond to a second view of the 3D color electronic display 200. The first and second sets of color beams 202', 202 "may each represent an RGB color model or color space of red, green, and blue, as shown in fig. 3B, by way of example and not limitation. Thus, the 3D color electronic display 200 may be substantially similar to the 3D electronic display 100 described above, while increasing the ability to represent color information. Further, the colored light beams 202 may be substantially similar to the light beams 102 described above with respect to the 3D electronic display 100, and further, the various colored light beams 202 may have or represent colors (e.g., red, green, or blue) that are different from one another, and the combination of the different colors is in a direction corresponding to different views of the 3D colored electronic display 200.

As shown in fig. 3A-3B, the 3D color electronic display 200 includes a plate light guide 210. The plate light guide 210 is configured to guide the light beams 204 of different colors. For example, the different colors of the guided light beam 204 may include the colors red, green, and blue of a red-green-blue (RGB) color model. Furthermore, the plate light guide 210 is configured to guide the light beams 204 of different colors at different color-dependent propagation angles within the plate light guide. As shown in fig. 3B, a first directed color beam 204 '(e.g., a red beam) that may be directed at a first color-dependent propagation angle γ', a second directed color beam 204 "(e.g., a green beam) that may be directed at a color-dependent second propagation angle γ", and a third directed color beam 204 '"(e.g., a blue beam) that may be directed at a third color-dependent propagation angle γ'".

The plate light guide 210 may be substantially similar to the plate light guide 110 described above with respect to the 3D electronic display 100, except that it is configured to guide different color light beams 204. For example, the plate light guide 210 may be a slab optical waveguide, which is a planar piece of dielectric material configured to guide light by total internal reflection. Further, according to some examples, the guided color light beams 204 in the plate light guide 210 can be collimated light beams (i.e., collimated color light beams), as described above with respect to the 3D electronic display 100.

The 3D color electronic display 200 shown in fig. 3A and 3B also includes a multibeam diffraction grating 220, according to some embodiments, the multibeam diffraction grating 220 may be at or adjacent a surface (e.g., a front surface or a top surface) of the plate light guide 210. Multibeam diffraction grating 220 is configured to couple out a portion of each of the different-color guided light beams 204 as separate pluralities of coupled-out light beams (i.e., different color light beams 202) of respective different colors. For example, there may be a separate plurality of coupled-out color beams 202 for each of the different colors of the directed color beams 204. According to various embodiments, the separate pluralities of respective coupled-out light beams 202 have different body angular directions representing different views of the 3D color electronic display. For example, a 3D color electronic display view may be represented by a set of coupled-out light beams 202 (e.g., a set of light beams 202' or 202 ") pointing at or having substantially the same principal angular direction, where a different coupled-out light beam 202 of the set corresponds to each different color of the directed color light beam 204. In combination, the plate light guide 210 and multibeam diffraction grating 220 provide or function as a backlight (i.e., a diffraction grating-based backlight) for the 3D color electronic display 200.

According to some embodiments, multibeam diffraction grating 220 may be substantially similar to multibeam diffraction grating 120 described above with respect to 3D electronic display 100. For example, the multibeam diffraction grating 220 may have a substantially rectangular shape with diffractive features comprising one or both of curved grooves in the plate light guide surface and curved ridges (i.e., continuously curved or piecewise curved) on the plate light guide surface. Furthermore, the diffractive features, whether curved or not, may be spaced apart from one another by a spacing between the diffractive features that varies as a function of distance across the multibeam diffraction grating 220 (e.g., a "chirped" spacing). That is, the multibeam diffraction grating 220 may comprise a chirped diffraction grating, e.g., one or more of a linearly chirped diffraction grating, a non-linearly chirped diffraction grating, etc., as described above with respect to the multibeam diffraction grating 120.

Further, in some embodiments, the multibeam diffraction grating 220 may be a member of an array of multibeam diffraction gratings that is substantially similar to the multibeam diffraction grating array 120 of the 3D electronic display 100, as described above. In particular, multibeam diffraction grating array 220 of 3D color electronic display 200 may be arranged in a plurality of offset rows. In some embodiments, adjacent rows of multibeam diffraction gratings 220 in the array may be offset from each other by a distance of approximately one-half (1/2) in the row direction between multibeam diffraction gratings in offset rows (i.e., pitch). In other examples, another offset may be used, including but not limited to one-third of the pitch (1/3), one-fourth (1/4), etc. Further, in some examples, the spacing between offset rows of multibeam diffraction gratings 220 in the array is the pitch of, or the spacing between, the multibeam diffraction gratings 220 in the offset rows. In other examples, the spacing may include, but is not limited to, one-third of the pitch (1/2), one-fourth (1/4), and so forth.

As shown in fig. 3A-3B, the 3D color electronic display 200 also includes a plurality of light valves 230. According to various embodiments, the plurality of light valves 230 is configured to modulate the coupled-in light beams 202 of different colors with a plurality of separate coupled-out light beams. Further, according to various embodiments, the light valves 230 of the plurality of light valves include color filters corresponding to different colors of the coupled light beam 202. In particular, a first light valve 230 of the plurality of light valves may have a color filter corresponding to a first color of the different colors; a second light valve 230 of the plurality of light valves may have a color filter corresponding to a second color; and different colors for the coupled-in light beam 202 (e.g., or equivalent to the different colored guided light beam 204). For example, the color filters of the plurality of light valves 230 may include a red color filter, a green color filter, and a blue color filter corresponding to the RGB color model. For example, the use of color filters (e.g., red, green, blue) may facilitate the display of color images and other information without the need to sequentially modulate the light of the different colored guided light beams 204.

In various examples, different types of light valves may be employed in the plurality of light valves 230, including but not limited to one or more of liquid crystal light valves, electrowetting light valves, and electrophoretic light valves. For example, the plurality of light valves may be a liquid crystal light valve array (e.g., a commercial liquid crystal light valve array), wherein a "pixel" of the liquid crystal light valve array includes sub-cells or "sub-pixels" (e.g., RGB sub-pixels) corresponding to each of the different colors. According to some embodiments, the plurality of light valves 230 may be substantially similar to the light valves in the light valve array 130 described above with respect to the 3D electronic display 100.

According to various embodiments, the color-dependent propagation angle of the different color guided light beams 204 results in different principal angular directions of the coupled-out light beams 202 corresponding to the respective different colors. In particular, due to the different color-dependent propagation angles, the outcoupled light beam 202 corresponding to a particular color (e.g., red, green, or blue) may appear to emanate from a color-dependent virtual point source. In fig. 3B, the color dependent virtual point sources are shown as stars, labeled, for example, as "R", "G", and "B" to correspond to the colors "red", "green", and "blue" for simplicity of illustration. The dashed lines emanating from the respective color-dependent virtual point sources show the span of the virtual beam of light (i.e., the virtual span of the beam of light) for each color. In particular, each virtual point source has a span extending to opposite ends of the multibeam diffraction grating 220, for example. Furthermore, due to the different color-dependent propagation angles of the guided light beam 204, the different color-dependent virtual point sources are laterally displaced from each other.

Due to the different color-dependent propagation angles of the guided light beam 204, the coupled-out light beam 202 corresponding to the first color may leave the multibeam diffraction grating 220 in a principal angular direction such that the coupled-out light beam 202 of the first color is preferentially directed through and thereby modulated by the light valves 230 having color filters corresponding to the first color. Similarly, the coupled-out light beam 202 corresponding to the second color may exit the multibeam diffraction grating 220 at a principal angular direction such that the second color coupled light beam 202 is modulated by another light valve 230 having a second color filter. As a result, the light valve 230 having the color filter of the first color may be configured to preferentially receive and modulate the coupled-out light beam 202 of the first color. Similarly, a light valve 230 having a second color filter may be configured to preferentially receive and modulate the coupled light beam 202 of the second color, and so on.

According to some embodiments (e.g., as shown in fig. 3A), the 3D color electronic display 200 may further include a light source 240. The light sources 240 are configured to provide the guided light beams 204 as different colors for transmission in the plate light guide 210. In particular, according to some embodiments, the guided light is light from a light source 240 that is coupled to an edge (or input end) of the plate light guide 210. For example, a lens, collimating reflector, or similar device (not shown) may help couple light into the plate light guide 110 at its input end or edge. In various examples, light source 240 may include virtually any light source, including but not limited to a Light Emitting Diode (LED) and one or more of any of the light sources described herein. In some examples, the light source 240 may include a light emitter configured to produce substantially monochromatic light having a narrow-band spectrum represented 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 various embodiments, the light source 240 has multiple light emitters coupled to the plate light guide 210 to provide different colors of the guided light beam 204. In particular, different light emitters may be configured to provide different colors of light corresponding to different colors of the guided light beam 204. Furthermore, the light emitters may be laterally offset or displaced (e.g. in a direction corresponding to the general propagation direction of the emitted light). According to various embodiments, the lateral displacement of the light emitters may be configured to determine the color-dependent propagation angle of the light beam 204 corresponding to different colors of light produced by the light emitters of the light source 240.

According to some examples of the principles described herein, a method of 3D electronic display operation is provided. In particular, 3D information may be displayed using a method of 3D electronic display operation. Furthermore, according to various embodiments of methods of 3D electronic display operation, 3D information may be displayed with enhanced perceptual resolution.

Fig. 4 illustrates a flow chart of a method 300 of three-dimensional (3D) electronic display operation in an example according to an embodiment consistent with the principles described herein. As shown in fig. 4, a method 300 of 3D electronic display operation includes directing 310 light as a beam of light at a non-zero propagation angle in a plate light guide. In some examples, the plate light guide and the guided light may be substantially similar to the plate light guide 110 and the guided light beam 104 described above with respect to the 3D electronic display 100. In particular, the plate light guide directs the light beam according to the total internal emission guide 310, and in some examples, the directed light beam may be collimated. Further, according to some embodiments, the plate light guide may be a substantially planar dielectric optical waveguide or a slab waveguide (e.g., a planar dielectric slab).

As shown in fig. 4, the method 300 of 3D electronic display operation further includes diffractively coupling 320 a portion of the guided light beam using an array of multibeam diffraction gratings arranged in offset rows. According to various embodiments, the portion of the guided light beam that is diffractively coupled out 320 of the plate light guide 320 comprises a plurality of light beams that are directed away from the surface of the plate light guide at a plurality of different principal angular directions (also referred to herein as "differently directed light beams" and "outcoupled light beams"). In particular, in various embodiments, a light beam of the plurality of light beams directed away from the plate light guide surface has a different principal angular direction than other light beams of the plurality of light beams. Further, according to various embodiments, the plurality of different principal angular directions of the plurality of light beams correspond to different views of the 3D electronic display.

In some embodiments, a portion of the diffractively coupled-out 320 is guided light using or employing a multibeam diffraction grating array located at or adjacent to a surface of the plate light guide. For example, the multibeam diffraction gratings of the array may be formed on or within a surface (e.g., a top surface) of the plate light guide as grooves, ridges, etc., and may be formed from the material of the plate light guide. In other examples, the multibeam diffraction gratings of the array may include a film on a plate light guide surface.

In some examples, the array of multibeam diffraction gratings is substantially similar to multibeam diffraction grating array 120 described above with respect to 3D electronic display 100. For example, a first row of multibeam diffraction gratings of the array may be offset in a row direction relative to a second row of the multibeam diffraction grating array adjacent to the first row. Further, for example, the offset may be about half of the pitch of the multibeam diffraction gratings or the spacing therebetween in the offset rows of the array (1/2). In some examples, a spacing between adjacent offset rows of the multibeam diffraction grating array is about half of a multibeam diffraction grating spacing or pitch in the offset rows (1/2). According to some embodiments, for example, a combination of half the spacing offset (1/2) of adjacent offset rows and half the spacing between adjacent offset rows of the multibeam diffraction grating array may help provide approximately two (2) times the physical or actual pixel resolution of the 3D electronic display.

The method 300 of 3D electronic display operation illustrated in fig. 4 further includes modulating 330 the plurality of coupled-out light beams using a plurality of light valves. For example, the modulated differently directed light beams coupled out 320 by the multibeam diffraction grating may represent pixels of a 3D electronic display. According to some examples, the plurality of light valves may be substantially similar to the light valve array 130 described above with respect to the 3D electronic display 100. For example, the plurality of light valves may include a plurality of liquid crystal light valves, or a plurality of electrowetting light valves, or a plurality of electrophoretic light valves, or the like, or any combination thereof.

In some embodiments, modulating 330 the light beam includes modulating differently oriented light beams from selected multibeam diffraction gratings of the array using a subset of light valves. In these embodiments, the differently directed light beams modulated by the subset of light valves represent superpixels of the 3D electronic display. In addition, each light valve in the subset modulates a different one of the plurality of differently directed light beams of the selected multibeam diffraction grating. In some embodiments, a super pixel may comprise a rectangular arrangement of light valves. In some embodiments, the rectangular arrangement of light valves of the superpixel may have approximately half as many light valves in a direction orthogonal to the row direction of the offset rows of the multibeam diffraction grating than in the row direction, i.e., the number of light valves in the row direction may be twice the number of light valves in a direction orthogonal to the row direction.

According to some examples of the principles described herein, a method of 3D color electronic display operation is provided. In particular, the method of 3D color electronic display operation may be used to display 3D information including color content. For example, the 3D information may include color content represented by a color space or gamut. According to various embodiments, a method of 3D color electronic display operation facilitates the use of spatially multiplexed colors, spaces, schemes, or color gamuts employing light valves with color filters.

Fig. 5 illustrates a flow chart of a method 400 of three-dimensional (3D) color electronic display operation in an example according to an embodiment consistent with the principles described herein. As shown in FIG. 5, a method 400 of 3D electronic display operation includes directing 410 light in a plate light guide, where the light includes a plurality of differently colored light beams. Further, according to various embodiments, directing 410 light includes directing light beams of different colors at respective different color-dependent propagation angles (i.e., non-zero color-dependent propagation angles). In some examples, the plate light guide and the different colored guided light beam may be substantially similar to the plate light guide 210 and the different colored guided light beam 204 described above with respect to the 3D color electronic display 200. In particular, the plate light guide guides 410 the guided light beam according to total internal reflection, and in some examples may collimate the guided light beam. Further, in some embodiments, the plate light guide may be a substantially planar dielectric optical waveguide or a slab waveguide (e.g., a planar dielectric slab).

As shown in fig. 5, the method 300 of 3D color electronic display operation further includes diffractively coupling a portion of the guided light beam of each different color out 420 using a multibeam diffraction grating. According to various embodiments, portions of the respective different colored guided light beams are diffractively coupled out 420 as separate out coupled light beams directed away from the surface of the plate light guide. Furthermore, the separated plurality of coupled-out light beams have different principal angular directions representing different views of the 3D color electronic display. The coupled-out light beams are also referred to herein as "differently directed light beams". In some examples, the multibeam diffraction grating used to diffractively couple out 420 is substantially similar to multibeam diffraction grating 220 described above with respect to 3D color electronic display 200.

In particular, the multibeam diffraction grating 220 may be located at or adjacent to a surface of a plate light guide, for example. In some examples, the multibeam diffraction grating may be formed on or within a surface (e.g., a top surface) of the plate light guide as grooves, ridges, etc., and may be formed from the material of the plate light guide. In other examples, the multibeam diffraction grating may include a film on a surface of the plate light guide.

In some embodiments, the multibeam diffraction grating to diffractively couple out a portion of the 420 different color guided light beams is a member of an array of multibeam diffraction gratings. In some embodiments, a first row of the array of multibeam diffraction gratings may be offset in a row direction of the array relative to a second row adjacent to the first row of the array of multibeam diffraction gratings. Further, for example, the offset may be about half of the pitch of the multibeam diffraction gratings in the offset row or the spacing therebetween (1/2). In some examples, a spacing between adjacent offset rows of the multibeam diffraction grating array is about half of a multibeam diffraction grating spacing or pitch in the offset rows (1/2). According to some embodiments, for example, a combination of half the spacing offset (1/2) of adjacent offset rows and half the spacing between adjacent offset rows may help provide approximately two (2) times the physical or actual pixel resolution of a 3D electronic display.

According to some examples, the method 400 of 3D color electronic display operation further includes modulating 430 the separated plurality of differently colored outcoupled beams using a light valve array. According to various embodiments, the light valves of the array comprise color filters of different colors corresponding to the respective separated plurality of coupled-out light beams. Furthermore, the light valves of the array of light valves are arranged to correspond to different predetermined principal angular directions of the respective separated plurality of coupled-out light beams. Differently directed beams of light using the modulation 430 of the filter equipped with light valves of the light valve array may represent color pixels of the 3D electronic display.

According to some examples, the light valve array may be substantially similar to the plurality of light valves 230 described above with respect to the 3D color electronic display 200. For example, the plurality of light valves may include a plurality of liquid crystal light valves or a plurality of electrowetting light valves, or a plurality of electrophoretic light valves, or the like, or any combination thereof. Further, for example, different ones of the plurality of light valves may include a color filter corresponding to each different color of the different colored light beams of 410 guided in the plate light guide. In particular, in some embodiments, the different colors of the 410 directed light beams include red, green, and blue of a red-green-blue (RGB) color model. In these embodiments, the color filters may include a red color filter, a green color filter, and a blue color filter corresponding to the RGB color model.

Thus, examples of 3D electronic displays, 3D color electronic displays, methods of 3D electronic display operation, and methods of 3D color electronic display operation have been described that employ one or both of an array of multibeam diffraction gratings and light valves with color filters arranged in offset rows. It should be understood that the above-described examples are only examples of some of the many specific examples that represent the principles described herein. It is clear that a person skilled in the art can easily devise many other arrangements without departing from the scope defined by the appended claims.

Claims (20)

1. A 3D electronic display, comprising:

a plate light guide configured to guide a light beam at a non-zero propagation angle;

an array of multibeam diffraction gratings arranged in a plurality of offset rows, the multibeam diffraction gratings of the array configured to diffractively couple out a portion of the guided light beam as a plurality of coupled-out light beams having different principal angular directions corresponding to different views of the 3D electronic display; and

a light valve array configured to modulate a plurality of coupled-out light beams corresponding to different views of the 3D electronic display, the modulated plurality of coupled-out light beams representing pixels of the 3D electronic display, wherein a subset of light valves of the light valve array is configured to modulate the plurality of coupled-out light beams from a selected multibeam diffraction grating of the array of multibeam diffraction gratings, the subset of light valves representing superpixes of the 3D electronic display, each light valve of the superpixes configured to modulate a different coupled-out light beam of the selected multibeam diffraction grating, the superpixes comprising a rectangular arrangement of light valves of the subset, the rectangular arrangement having half as many light valves in a direction orthogonal to a row direction of a plurality of offset rows of the array of multibeam diffraction gratings as the row direction.

2. The 3D electronic display of claim 1, wherein the multibeam diffraction grating comprises a linearly chirped diffraction grating.

3. The 3D electronic display of claim 1, wherein the multibeam diffraction grating is at a surface of the plate light guide, the multibeam diffraction grating having a rectangular shape with diffractive features comprising one or both of curved grooves in the plate light guide surface and curved ridges on the plate light guide surface.

4. The 3D electronic display of claim 1, wherein a first row of the multibeam diffraction grating array is offset in a row direction relative to a second row of the multibeam diffraction grating array adjacent to the first row, the offset being half a pitch of the multibeam diffraction gratings in the first row of the multibeam diffraction grating array.

5. The 3D electronic display of claim 1, wherein a center-to-center spacing between adjacent offset rows of the array of multibeam diffraction gratings is half a pitch of multibeam diffraction gratings in the offset rows of the array of multibeam diffraction gratings.

6. The 3D electronic display of claim 1, further comprising a plurality of differently colored light sources both laterally displaced from each other in a row direction of the offset rows of the multibeam diffraction grating array and coupled to the plate light guide, each light source configured to produce a light beam of a particular color that is different from the colors produced by other light sources of the plurality of light sources, wherein the plate light guide is configured to direct the differently colored light beams at respective non-zero propagation angles that depend on the lateral displacement of the differently colored light sources, wherein the respective non-zero propagation angles of the differently colored light beams are configured to provide an outcoupled light beam of each different color for each different view of the 3D electronic display.

7. The 3D electronic display of claim 6, wherein the light valves of the light valve array comprise liquid crystal light valves, a first liquid crystal light valve having a color filter that is a different color than a color filter of a second liquid crystal light valve in the light valve array.

8. A 3D color electronic display, comprising:

a plate light guide configured to guide light beams of different colors at different color-dependent propagation angles;

a multibeam diffraction grating at the plate light guide surface configured to diffractively couple out a portion of the guided light beam of each color as a respective different color of a separate plurality of coupled-out light beams having different principal angular directions representing different views of the 3D color electronic display, the multibeam diffraction grating being a member of an array of multibeam diffraction gratings arranged in a plurality of offset rows at the plate light guide surface; and

a plurality of light valves configured to modulate the separate plurality of coupled-out light beams of the respective different colors, a light valve of the plurality of light valves having a color filter corresponding to the respective different color of the coupled-out light beam, wherein a subset of the plurality of light valves is configured to modulate the plurality of coupled-out light beams from a selected multibeam diffraction grating of the multibeam diffraction grating array, the subset of light valves representing a superpixel of the 3D color electronic display, each light valve of the superpixel configured to modulate a different coupled-out light beam of the selected multibeam diffraction grating, the superpixel comprising a rectangular arrangement of light valves of the subset, the rectangular arrangement having half as many light valves in a row direction orthogonal to a row direction of a plurality of offset rows of the multibeam diffraction grating array in the row direction.

9. The 3D color electronic display of claim 8, wherein a principal angular direction of the coupled-out light beam is a function of a color-dependent propagation angle of the guided light beam.

10. The 3D color electronic display of claim 8, wherein the different colors of the guided light beams comprise red, green, and blue of a red-green-blue (RGB) color model, and wherein the color filters comprise a red color filter, a green color filter, and a blue color filter corresponding to the RGB color model, and wherein the view of the 3D color electronic display comprises a red light beam, a green light beam, and a blue light beam.

11. The 3D color electronic display of claim 8, wherein the multibeam diffraction grating has a rectangular shape with diffractive features comprising one or both of curved grooves in the plate light guide surface and curved ridges on the plate light guide surface.

12. The 3D color electronic display of claim 8, wherein adjacent rows of the multibeam diffraction grating are offset from each other in a row direction by half a pitch of the multibeam diffraction grating of the adjacent rows.

13. The 3D color electronic display of claim 12, wherein a spacing between adjacent rows of the multibeam diffraction grating is half a pitch of the multibeam diffraction grating.

14. The 3D color electronic display of claim 8, further comprising a light source having a plurality of light emitters configured to emit light beams of different colors, the light source coupled to the plate light guide, wherein the light emitters of respective different colors are laterally offset from one another to determine different color-dependent propagation angles of the different color guided light beams.

15. A method of 3D electronic display operation, the method comprising:

directing light as a beam at a non-zero propagation angle in a plate light guide;

diffractively coupling out a portion of the guided light beam using an array of multibeam diffraction gratings arranged in offset rows on the plate light guide, wherein the diffractively coupled-out portion of the guided light beam comprises producing a plurality of coupled-out light beams directed away from the plate light guide in a plurality of different principal angular directions corresponding to different views of the 3D electronic display; and is

Modulating a plurality of coupled-out light beams using a plurality of light valves, the modulated plurality of coupled-out light beams representing pixels of the 3D electronic display, wherein modulating the plurality of coupled-out light beams comprises modulating differently oriented light beams coupled-out by a selected multibeam diffraction grating in the array using a subset of light valves of the plurality of light valves, the differently oriented light beams being modulated by a subset of light valves representing superpixels of the 3D electronic display, each light valve in the subset modulating a different one of the differently oriented light beams of the selected multibeam diffraction grating, and wherein the superpixel comprises a rectangular arrangement of light valves in the subset having twice as many light valves in a row direction of an offset row of the multibeam diffraction grating array as in a direction perpendicular to the row direction.

16. The method of 3D electronic display operation of claim 15, wherein a first row of multibeam diffraction gratings of the array is offset in a row direction relative to a second row adjacent to the first row, the offset being half a pitch of the multibeam diffraction gratings in the offset row, and wherein a spacing between adjacent offset rows is half a pitch of the multibeam diffraction gratings in offset rows.

17. The method of 3D electronic display operation of claim 15, further comprising generating a plurality of differently colored light beams using a plurality of differently colored light emitters, each differently colored light beam of the plurality of light beams being guided in the plate light guide at a different color-dependent non-zero propagation angle.

18. A method of 3D color electronic display operation, the method comprising:

directing a plurality of differently colored light beams at different color-dependent propagation angles within a plate light guide;

diffractively coupling out a portion of the guided light beam of each color as a respective different color of a separate plurality of coupled-out light beams having different principal angular directions representing different views of a 3D color electronic display using a multibeam diffraction grating at a surface of the plate light guide, the multibeam diffraction grating being a member of an array of multibeam diffraction gratings arranged in a plurality of offset rows at the surface of the plate light guide; and

modulating the separated plurality of coupled-out light beams of the respective different colors using an array of light valves having color filters corresponding to the respective different colors of the coupled-out light beams, wherein a subset of the light valves of the array of light valves is configured to modulate coupled-out light beams from a selected multibeam diffraction grating of the multibeam diffraction grating array, the subset of light valves representing a superpixel of the 3D electronic display, each light valve of the superpixel being configured to modulate a different coupled-out light beam of the selected multibeam diffraction grating, the superpixel comprising a rectangular arrangement of light valves of the subset having half as many light valves in a direction orthogonal to a row direction of a plurality of offset rows of the multibeam diffraction grating array in the row direction.

19. The method of 3D color electronic display operation of claim 18, wherein a first row of the multibeam diffraction grating is offset in a row direction relative to a second row adjacent to the first row by half a distance between multibeam diffraction gratings in adjacent offset rows, and wherein a spacing between adjacent offset rows is half a distance of a multibeam diffraction grating in the offset rows.

20. The method of 3D color electronic display operation of claim 18, wherein the different colors of the guided light beam comprise red, green, and blue of a red-green-blue (RGB) color model, and wherein the color filters comprise a red color filter, a green color filter, and a blue color filter corresponding to the RGB color model.