Patent Description:
Electronic displays are a nearly ubiquitous medium for communicating information to users of a wide variety of devices and products. Most commonly employed electronic displays include the cathode ray tube (CRT), plasma display panels (PDP), liquid crystal displays (LCD), electroluminescent displays (EL), organic light emitting diode (OLED) and active matrix OLEDs (AMOLED) displays, electrophoretic displays (EP) and various displays that employ electromechanical or electrofluidic light modulation (e.g., digital micromirror devices, electrowetting displays, etc.). Generally, electronic displays may be categorized as either active displays (i.e., displays that emit light) or passive displays (i.e., displays that modulate light provided by another source). Among the most obvious examples of active displays are CRTs, PDPs and OLEDs/AMOLEDs. Displays that are typically classified as passive when considering emitted light are LCDs and EP displays. Passive displays, while often exhibiting attractive performance characteristics including, but not limited to, inherently low power consumption, may find somewhat limited use in many practical applications given the lack of an ability to emit light.

To overcome the limitations of passive displays associated with emitted light, many passive displays are coupled to an external light source. The coupled light source may allow these otherwise passive displays to emit light and function substantially as an active display. Examples of such coupled light sources are backlights. A backlight may serve as a source of light (often a panel backlight) that is placed behind an otherwise passive display to illuminate the passive display. For example, a backlight may be coupled to an LCD or an EP display. The backlight emits light that passes through the LCD or the EP display. The light emitted is modulated by the LCD or the EP display and the modulated light is then emitted, in turn, from the LCD or the EP display. Often backlights are configured to emit white light. Color filters are then used to transform the white light into various colors used in the display. The color filters may be placed at an output of the LCD or the EP display (less common) or between the backlight and the LCD or the EP display, for example.

<CIT> discloses systems and methods that relate to frame formatting supporting mixed two and three dimensional video data communication. For example, frames in frame sequence(s) may be formatted to indicate that a first screen configuration is to be used for displaying first video content, that a second screen configuration is to be used for displaying second video content, and so on. The screen configurations may be different or the same. In another example, the frames in the frame sequence(s) may be formatted to indicate that the first video content is to be displayed at a first region of a screen, that the second video content is to be displayed at a second region of the screen, and so on. The regions of the screen may partially overlap, fully overlap, not overlap, be configured such that one or more regions are within one or more other regions.

<CIT> discloses a head tracking stereoscopic display which has a first combining light source composed of two line-shaped light sources and a second combining light source composed of two line-shaped light sources. The first combining light source is used when the head of a viewer is shifted by the distance between the eyes E in the horizontal direction on the basis of a certain position, and the second combining light source is used when the head of the viewer is shifted by the distance between the eyes E in the horizontal direction on the basis of a position shifted by E/<NUM> from the certain position. When the first combining light source is selected, the two line-shaped light sources in the first combining light source are alternately turned on and off. When the second combining light source is selected, the two line-shaped light sources in the second combining light source are alternately turned on and off. A right eye image and a left eye image are alternately displayed in synchronization with the alternate ON/OFF on an image display panel. Such control as to change the timing at which images are alternately displayed and such control as to select the combining light source are suitably carried out on the basis of information relating to the head position from the head position detection means.

Examples and embodiments in accordance with the principles described herein provide a multiview backlight and a multiview display that utilizes the multiview backlight. In particular, embodiments consistent with the principles described herein provide a multiview backlight employing arrays of active emitters configured to provide directional light beams having a plurality of different principal angular directions. Further, according to various embodiments, active emitters of the active emitter arrays are sized relative to view pixels of a multiview pixel in a multiview display, and may also be spaced apart from one another in a manner corresponding to a spacing of multiview pixels of the multiview display. According to various embodiments, the different principal angular directions of the light beams provided by the active emitters correspond to different directions of various different views of the multiview display or equivalently of a multiview image displayed by the multiview display, according to various 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 range of the 2D display). A conventional liquid crystal display (LCD) found in may smart phones and computer monitors are examples of 2D displays. In contrast and 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. Uses of multiview backlighting and multiview displays applicable to the display of multiview images described herein include, but are not limited to, mobile telephones (e.g., smart phones), watches, tablet computers, mobile computers (e.g., laptop computers), personal computers and computer monitors, automobile display consoles, camera displays, and various other mobile as well as substantially non-mobile display applications and devices.

<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> configured to display a multiview image to be viewed. The screen <NUM> may be a display screen of a telephone (e.g., mobile telephone, smart phone, etc.), a tablet computer, a laptop computer, a computer monitor of a desktop computer, a camera display, or an electronic display of substantially any other device, for example.

The multiview display <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 2D display may be substantially similar to the multiview display <NUM>, except that the 2D Display is generally configured to provide a single view (e.g., one view similar to view <NUM>) of a displayed image as opposed to the different views <NUM> of the multiview image provided by the multiview display <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.

The term 'multiview' as used in the terms `multiview image' and `multiview display' is defined herein 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 two or more different views (e.g., a minimum of three views and generally more than three views), by definition herein. In some embodiments, `multiview display' as employed herein may be used to explicitly distinguish from a stereoscopic display that includes only two different views to represent a scene or an image. Note however, while multiview images and multiview displays may include more than two views, by definition herein, multiview images may be viewed (e.g., on a multiview display) as a stereoscopic pair of images by selecting only two of the multiview views to view at a time (e.g., one view per eye).

A `multiview pixel' is defined herein as a set of view pixels representing pixels of views in each of a similar plurality of different views of a multiview display. In particular, a multiview pixel may have an individual view pixels corresponding to or representing a particular view pixel in each of the different views of the multiview image. 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 corresponding to pixels located at {x<NUM>, y<NUM>} in each of the different views of a multiview image, while a second multiview pixel may have individual view pixels corresponding to pixels located at {x<NUM>, y<NUM>} 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 include sixty-four (<NUM>) view pixels in associated with a multiview display having or providing <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.

Herein a 'collimator' is defined as substantially any optical device or apparatus that is configured to collimate light. According to various embodiments, an amount of collimation provided by the collimator may vary in a predetermined degree or amount from one embodiment to another. Herein, a `collimation factor' is defined as a degree to which light is collimated. In particular, a collimation factor defines an angular spread of light rays within a collimated beam of light, by definition herein. For example, a collimation factor σ may specify that a majority of light rays in a beam of collimated light is within a particular angular spread (e.g., +/- σ degrees about a central or principal angular direction of the collimated light beam). The light rays of the collimated light beam may have a Gaussian distribution in terms of angle and the angular spread may be an angle determined by at one-half of a peak intensity of the collimated light beam, according to some examples.

Herein, an 'active emitter' is defined as an active source of light (e.g., an optical emitter configured to produce and emit light when activated). As such, an active emitter does not receive light from another source of light, by definition. Instead, the active emitter directly generates light when activated. The active emitter may be activated by applying a power source such as a voltage or a current, by definition herein. For example, the active emitter may comprise an optical emitter such as a light emitting diode (LED) that emits light when activated or turned on. The LED may be activated by applying a voltage to terminals of the LED, for example. In particular, herein the light source may be substantially any active source of light or comprise substantially any active optical emitter including, but not limited to, one or more of a light emitting diode (LED), a laser, an organic light emitting diode (OLED), a polymer light emitting diode, a plasma-based optical emitter, and a micro LED (µLED). The light produced by the active emitter may have a color (i.e., may include a particular wavelength of light), or may be a plurality or range of wavelengths (e.g., polychromatic light or white light). Different colors of light provided or produced by an active emitter may include, but are not limited to, primary colors (e.g., red, green, blue), for example. By definition herein, a `color emitter' is an active emitter that provides light having a color. In some embodiments, the active emitter may comprise a plurality of active emitters. For example, the active emitter may include a set or group of active emitters. In some embodiments, at least one of the active emitters in the set or group of active emitters may generate light having a color, or equivalently a wavelength, that differs from a color or wavelength of light produced by at least one other optical emitter of the plurality.

Further by definition herein, the term 'broad-angle' as in '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 sixty degrees (<NUM>°). In other embodiments, the broad-angle emitted light cone angle may be greater than about fifty degrees (<NUM>°), or greater than about forty degrees (<NUM>°). For example, the cone angle of the broad-angle emitted light may be about one hundred twenty degrees (<NUM>°). Alternatively, the broad-angle emitted light may have an angular range that is greater than plus and minus forty-five degrees (e.g., > ± <NUM>°) relative to the normal direction of a display. In other embodiments, the broad-angle emitted light angular range may be greater than plus and minus fifty degrees (e.g., > ± <NUM>°), or greater than plus and minus sixty degrees (e.g., > ± <NUM>°), or greater than plus and minus sixty-five degrees (e.g., > ± <NUM>°). For example, the angular range of the broad-angle emitted light may be greater than about seventy degrees on either side of the normal direction of the display (e.g., > ± <NUM>°). A 'broad-angle backlight' is a backlight configured to provide broad-angle emitted light, by definition herein.

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, 'an active emitter' means one or more arrays and as such, 'the active emitter' means 'the active emitter(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 backlight is provided. <FIG> illustrates a cross-sectional view of a multiview backlight <NUM> in an example, according to an embodiment consistent with the principles described herein. <FIG> illustrates a plan view of a multiview backlight <NUM> in an example, according to an embodiment consistent with the principles described herein. <FIG> illustrates a plan view of a multiview backlight <NUM> in an example, according to another embodiment consistent with the principles described herein. The multiview backlight <NUM> is configured to emit or provide directional light beams <NUM>. According to various embodiments, the directional light beams <NUM> provided by the multiview backlight <NUM> have directions corresponding to view directions of a multiview display or equivalently of a multiview image displayed by the multiview display.

The multiview backlight <NUM> illustrated in <FIG> comprises a first array of active emitters <NUM> spaced apart from one another. In some embodiments, the active emitters <NUM> may be arranged in a two-dimensional (2D) array (e.g., a rectangular array) having rows and columns, as illustrated in <FIG> and <FIG>. In other embodiments (not illustrated), the array of active emitters <NUM> may be either a one-dimensional (1D) such as a linear array or another 2D array including, but not limited to a circular array.

According to various embodiments, an active emitter <NUM> of the first array of active emitters <NUM> is configured to emit or provide light as a first plurality of the directional light beams <NUM>'. Further, the directional light beams <NUM>' provided by the active emitter <NUM> may have directions corresponding to the view directions of a multiview display or equivalently of a multiview image displayed by the multiview display. As such, the directional light beams <NUM> provided by the multiview backlight <NUM> may comprise the directional light beams <NUM>' of the first directional light beam plurality provided by the active emitter <NUM>, according to various embodiments. Differently directed, solid-line arrows in <FIG> represent directional light beams <NUM>' of the first directional light beam plurality, by way of illustration and not limitation.

As illustrated in <FIG>, the multiview backlight <NUM> further comprises a second array of active emitters <NUM>. Active emitters <NUM> of the second active emitter array are also spaced apart from one another, according to various embodiments. In some embodiments, an arrangement of active emitters <NUM> of the second array of active emitters <NUM> may be substantially similar to that of the array of active emitters <NUM>, as described above (e.g., a 2D array or a 1D array). Further, the second array of active emitters <NUM> is interleaved with or between active emitters <NUM> of the first array of active emitters <NUM>, according to various embodiments. In some embodiments, active emitters <NUM> of the second active emitter array may be interleaved about halfway between adjacent active emitters <NUM> of the first active emitter array.

For example, active emitters <NUM> of the second array of active emitters <NUM> may alternate with active emitters <NUM> of the first array of active emitters <NUM> along a row of the array, as illustrated in <FIG>. In another example, as illustrated in <FIG>, rows and columns of active emitters <NUM> of the second active emitter array may be interleaved with rows and columns of the active emitters <NUM> of the first active emitter array. As such, the active emitters <NUM> of the second active emitter array may be diagonally offset from the active emitters <NUM> of the first active emitter array, in some embodiments. In yet another embodiment illustrated in <FIG>, the active emitters <NUM> of the second active emitter array may alternate with active emitters <NUM> of the first active emitter array along both rows and columns. Further, as illustrated in <FIG>, the active emitters <NUM> of the second active emitter array may also be diagonally offset from adjacent active emitters <NUM> of the first active emitter array. Therefore, the active emitters <NUM> may alternate with adjacent active emitters <NUM> along each of the rows, the columns, and also along diagonals of the array, in some embodiments.

Note, <FIG> also illustrate in different embodiments active emitters <NUM> of the second active emitter array as being halfway (or centered) between active emitters <NUM> of the first active emitter array, by way of example and not limitation. In other embodiments (not illustrated), the active emitters <NUM> of the second active emitter array may be located other than halfway between adjacent active emitters <NUM> for the first active emitter array.

According to various embodiments, an active emitter <NUM> of the second array of active emitters <NUM> is configured to emit or provide light as a second plurality of directional light beams <NUM>". As with the first plurality of directional light beams <NUM>', the directional light beams <NUM>" may have directions corresponding to view directions of a multiview display or equivalently of a multiview image displayed by the multiview display. In particular, the directions of the directional light beams <NUM>" of the second directional light beam plurality may be equivalent to or have the same as the directions of the directional light beams <NUM> of the first directional light beam plurality, according to various embodiments. As such, the directional light beams <NUM> provided by the multiview backlight <NUM> may further comprise the directional light beams <NUM>" of the second directional light beam plurality provided by the active emitter <NUM>. In <FIG>, differently directed, dashed-line arrows represent the directional light beams <NUM>" of the second directional light beam plurality, by way of illustration and not limitation. The dashed arrows also distinguish the directional light beams <NUM>" from the directional light beams <NUM>' of the first directional light beam plurality, as illustrated.

According to various embodiments, a size of the active emitters <NUM>, <NUM> of the first and second active emitter arrays is comparable to a view pixel of a multiview display that employs the multiview backlight <NUM>. In particular, an active emitter size of each of the active emitter <NUM> of the first active emitter array and the active emitter <NUM> of the second active emitter array may be comparable to the view pixel size. In an embodiment according to the invention, the active emitter size is between about one half (<NUM>) and about two (<NUM>) times the view pixel size. For example, the active emitter size may be about equal to the view pixel size. In some embodiments, the view pixel size may be a size of a light valve of an array of light valves used to modulate the directional light beams <NUM>, <NUM>', <NUM>", provided by the multiview backlight <NUM> used by the multiview display (e.g., see discussion below). The size of the light valve may be an aperture size of the light valve or equivalently a center-to-center between light valves of the light valve array, for example.

In some embodiments, a distance between adjacent active emitters within one or both of the first array of active emitters <NUM> and the second array of active emitters <NUM> is comparable to or commensurate with a distance between multiview pixels of the multiview display that employs the multiview backlight <NUM>. In particular, a distance (e.g., center-to-center distance) between adjacent active emitters <NUM> of the first active emitter array may be about equal to a center-to-center distance between adjacent multiview pixels. The center-to-center distance may be defined along one or both of a row and a column of each of the first array of active emitters <NUM> with the multiview pixels may be arranged in a commensurate array, for example. Similarly, a center-to-center distance between adjacent active emitters <NUM> of the second active emitter array may be about equal to a center-to-center distance between adjacent multiview pixels. As a result, there may be a one-to-one or unique correspondence between a multiview pixel and an individual active emitter <NUM>, <NUM>, according to some embodiments.

By way of example and not limitation, <FIG> further illustrates an array of light valves <NUM> as well as multiview pixels <NUM> and view pixels for the purpose of facilitating discussion herein. The illustrated light valve array may be part of a multiview display that employs the multiview backlight <NUM>, for example. As illustrated, light valves <NUM> of the light valve array are configured to modulate the directional light beams <NUM>, e.g., the directional light beams <NUM>', <NUM>". Further, different ones of the directional light beams <NUM> having different principal angular directions pass through and may be modulated by different ones of the light valves <NUM> in the light valve array, as illustrated.

In some embodiments, a light valve <NUM> of the light valve array may correspond to a view pixel of the multiview display, while a set of the light valves <NUM> may correspond to a multiview pixel <NUM>. In particular, a different set of light valves <NUM> of the light valve array may be configured to receive and modulate the directional light beams <NUM>, <NUM>', <NUM>" from different ones of the active emitters <NUM>, <NUM>. As such, there may be one unique set of light valves <NUM> (or multiview pixel <NUM>) for each active emitter <NUM>, <NUM>, e.g., as illustrated with respect to active emitters <NUM>. In various embodiments, 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.

Further, in <FIG>, a size S of a view pixel corresponds to an aperture size of a light valve <NUM> in the light valve array, as illustrated. In other examples, the view pixel size may be defined as a distance (e.g., a center-to-center distance) between adjacent light valves <NUM> of the light valve array. For example, an aperture of the light valves <NUM> may be smaller than the center-to-center distance between the light valves <NUM> in the light valve array. Thus, the view pixel size may be defined as either the size of the light valve <NUM> or a size corresponding to the center-to-center distance between the light valves <NUM>, among other definitions. Also in <FIG>, a size s of the active emitters <NUM>, <NUM> is illustrated as comparable to the view pixel size S.

In some embodiments (e.g., as illustrated in <FIG>), an inter-element distance (e.g., center-to-center distance) between a pair of adjacent active emitters <NUM>, <NUM> may be equal to an inter-pixel distance (e.g., a center-to-center distance) between a corresponding pair of adjacent multiview pixels <NUM>, e.g., represented by light valve sets. For example, as illustrated in <FIG>, a center-to-center distance d between a first active emitter 110a and a second active emitter 110b is substantially equal to a center-to-center distance D between a first light valve set 104a and the second light valve set 104b, where each light valve set 104a, 104b represents a multiview pixel <NUM>. In other embodiments (not illustrated), the relative center-to-center distances of pairs of active emitters 110a, 110b (or active emitters <NUM>) and corresponding light valve sets 104a, 104b may differ, e.g., the active emitters <NUM>, <NUM> may have an inter-element spacing (i.e., center-to-center distance d) that is one of greater than or less than a spacing (i.e., center-to-center distance D) between light valve sets representing multiview pixels <NUM>.

In some embodiments, a shape of the active emitter <NUM>, <NUM> is analogous to a shape of the multiview pixel <NUM> or equivalently, a shape of the set of the light valves <NUM> corresponding to the multiview pixel <NUM>. For example, the active emitter <NUM>, <NUM> may have a square shape and the multiview pixel <NUM> (or an arrangement of a corresponding set of light valves <NUM>) may be substantially square. In another example, the active emitter <NUM>, <NUM> may have a rectangular shape, i.e., may have a length or longitudinal dimension that is greater than a width or transverse dimension. In this example, the multiview pixel <NUM> (or equivalently the arrangement of the set of light valves <NUM>) corresponding to the active emitter <NUM>, <NUM> may have an analogous rectangular shape. <FIG> illustrate a plan view of square-shaped active emitters <NUM>, <NUM> and corresponding square-shaped multiview pixels <NUM> (not illustrated) comprising square sets of light valves <NUM>. In yet other examples (not illustrated), the active emitters <NUM>, <NUM> and the corresponding multiview pixels <NUM> have various shapes including or at least approximated by, but not limited to, a triangular shape, a hexagonal shape, and a circular shape. More generally, the shape may represent substantially any tileable shape.

According to some embodiments, an active emitter <NUM>, <NUM> of one or both of the first active emitter array and the second active emitter array may comprise a micro light emitting diode (microLED or µLED). Herein, µLED is defined as a microscopic light emitting diode (LED), i.e., an LED having microscopic dimensions. In some embodiments, the µLED may comprise a plurality of µLEDs that, when combined, have size that is comparable to the view pixel size. According to some embodiments, an active emitter <NUM>, <NUM> of one or both of the first active emitter array and the second active emitter array may comprise an organic light emitting diode (OLED). As defined herein, an OLED is an emitter having an emissive electroluminescent film or layer comprising an organic compound configured to emit light in response to an electric current or similar electrical stimulus. In other embodiments, another type of active optical emitter may be used as the active emitter <NUM>, <NUM> such as, but not limited to, a high intensity LED and a quantum dot LED having a size comparable to the view pixel size.

In some embodiments, the active emitter <NUM>, <NUM> may be configured to provide light that is substantially monochromatic having a particular color (i.e., the light may include a particular wavelength of light). In other embodiments, the active emitter <NUM>, <NUM> may be configured to provide polychromatic light such as, but not limited to, white light, that includes a plurality or range of wavelengths. For example, active emitter <NUM>, <NUM> may be configured to provide one or more of red light, green light, blue light, or a combination thereof. In another example, the active emitter <NUM>, <NUM> may be configured to provide light that is substantially white light (i.e., the active emitter <NUM>, <NUM> may be a white µLED or white OLED). In some embodiments, the active emitter <NUM>, <NUM> may include a micro-lens, a diffraction grating, or another optical film or component configured to provide one or both of collimation (e.g., according to a collimation factor) and polarization control of emitted light or equivalent of the directional light beams <NUM>, <NUM>', <NUM>". The micro-lens, the diffraction grating, or the other optical film or component may also or alternatively be configured to control a direction of the directional light beams <NUM>, <NUM>', <NUM>". Alternatively, one or both of the collimation and polarization control may be provided by an optical layer or film between the active emitter arrays and the light valve array, for example.

Active emitters <NUM>, <NUM> of the first and second active emitter arrays may be independently controlled, activated, or powered to provide local dimming and also to enable switching between directional light beam production by the first and second active emitter arrays, according to some embodiments. In particular, in some embodiments, the active emitter(s) <NUM> of the first active emitter array may be configured to provide by selective activation the first plurality of directional light beams <NUM>', e.g., during a first time interval or a particular mode. Similarly, the active emitter(s) <NUM> of the second active emitter array may be configured to provide the second plurality of directional light beams <NUM>" by selective activation, e.g., during a second time interval or a particular mode. In various embodiments, the first time interval and the second time interval may be alternating, sequential time intervals, as described further below.

<FIG> illustrates a cross-sectional view of a multiview backlight <NUM> in an example, according to an embodiment of the principles described herein. <FIG> a cross-sectional view of the multiview backlight <NUM> of <FIG> in an example, according to an embodiment of the principles described herein. The multiview backlight <NUM> illustrated in <FIG> comprises the first array of active emitters <NUM> and the second array of active emitters <NUM>. The array of light valves <NUM> is also illustrated in <FIG>.

As illustrated, the multiview backlight <NUM> is configured to provide selective activation of the first and second active emitter arrays during different time intervals. In particular, <FIG> illustrates the multiview backlight <NUM> during a first time interval T<NUM> and <FIG> illustrates the multiview backlight <NUM> during a second time interval T<NUM>. During the first time interval T<NUM> (<FIG>), the first array of active emitters <NUM> is selectively activated to provide the first plurality of directional light beams <NUM>', while the second array of active emitters <NUM> is selectively activated to provide the second plurality of directional light beams <NUM>" during the second time interval T<NUM>. The first time interval T<NUM> and the second time interval T<NUM> may alternate in a time-sequential manner, for example. As such, the array of light valve <NUM> may be time multiplexed such that directional light beams <NUM>' provided by the first array of active emitters <NUM> are modulated during the first time interval T<NUM> and directional light beams <NUM>" provided by the second array of active emitters <NUM> are modulated during the second time interval T<NUM>, according to some embodiments.

Time multiplexing of the array of light valves <NUM> may provide an effective doubling of a resolution of a multiview image displayed by a multiview display that includes the multiview backlight <NUM> and array of light valves <NUM>, as illustrated in <FIG> when compared to the same multiview display in which time multiplexing is not employed, for example. Moreover, the multiview image resolution may be selectively increased or decreased by either using or not using time multiplexing, according to various embodiments. Note that, as illustrated in <FIG>, the displayed multiview image may include four different views by way of example and not limitation.

In other embodiments, the first array of active emitters <NUM> may be configured to provide the first plurality of directional light beams <NUM>' during a first mode of the multiview backlight <NUM>. In particular, the first array of active emitters <NUM> may be activated during the first mode. The second array of active emitters <NUM> may be inactivated during the first mode, for example. Further, during a second mode, both the first array of active emitters <NUM> may be configured to provide the first plurality of directional light beams <NUM>' and the second array of active emitters <NUM> may be configured to provide the second plurality of directional light beams <NUM>" during a second mode of the multiview backlight <NUM>. In particular, both the first and second active emitter arrays may be activated during the second mode.

<FIG> illustrates a cross-sectional view of a multiview backlight <NUM> in an example, according to an embodiment of the principles described herein. <FIG> a cross-sectional view of the multiview backlight <NUM> of <FIG> in an example, according to an embodiment of the principles described herein. The multiview backlight <NUM> illustrated in <FIG> comprises the first array of active emitters <NUM> and the second array of active emitters <NUM>. The array of light valves <NUM> is also illustrated in <FIG>. Further, the multiview backlight <NUM> is illustrated during or in a first mode (Mode <NUM>) in Figured 4A, while the multiview backlight <NUM> is illustrated in <FIG> during or in a second mode (Mode <NUM>).

In particular, <FIG> illustrates the multiview backlight <NUM> during the first mode (Mode <NUM>) in which active emitters <NUM> of the first active emitter array are activated and active emitters <NUM> of the second active emitter array are inactivated. As illustrated, the active emitters <NUM> provide the directional light beams <NUM>' of the first directional light beam plurality when activated during the first mode (Mode <NUM>). These directional light beams <NUM>' may be modulated by the array of light valves <NUM> to provide a multiview image having a first quantity or number of different views characterized by a multiview pixel <NUM>. In particular, the multiview pixel <NUM> associated with an active emitter <NUM> during the first mode includes view pixels corresponding to eight (<NUM>) different views, as illustrated in <FIG> by way of example and not limitation.

<FIG> illustrates the multiview backlight <NUM> during the second mode (Mode <NUM>) in which both the active emitters <NUM> of the first active emitter array and the active emitters <NUM> of the second active emitter array are activated simultaneously. As illustrated, the active emitters <NUM>, <NUM> provide directional light beams <NUM>', <NUM>" of both of the first directional light beam plurality and the second directional light beam plurality when activated. In each of the first and second modes, light valves <NUM> of the light valve array may be used to modulate the directional light beams <NUM> (e.g., only the directional light beams <NUM>' in the first mode and directional light beams <NUM>', <NUM>" during the second mode) to provide the multiview image. Moreover, a resolution of the multiview image may be increase (e.g., doubled) in the second mode (Mode <NUM>) compared to the resolution in the first mode (Mode <NUM>). Of course, as illustrated in <FIG>, a quantity or number of views of the multiview image provided in the second mode (Mode <NUM>) is be less than (e.g., half of) a number of views of the multiview image provided in the first mode (Mode <NUM>). In particular, multiview pixels <NUM> are associated with each of the active emitters <NUM>, <NUM> and each of the multiview pixels <NUM> includes view pixels corresponding to four (<NUM>) different views in the second mode (Mode <NUM>), as illustrated in <FIG> by way of example and not limitation. Accordingly, switching between the first mode (Mode <NUM>) and the second mode (Mode <NUM>) may facilitate switching between a greater number of views (lower resolution) and a higher resolution (fewer views) of the multiview image.

Referring again to <FIG>, the multiview backlight <NUM> may further comprise a planar substrate <NUM>, in some embodiments. In particular, the active emitters <NUM>, <NUM> may be spaced apart across a surface of the planar substrate <NUM>. The planar substrate <NUM> may further comprise electrical interconnects to provide power to the active emitters <NUM>, <NUM>. In some embodiments, the planar substrate <NUM> is configured to be optically transparent or at least substantially optically transparent (i.e., may be a planar transparent substrate). For example, the planar substrate <NUM> may comprise an optically transparent material capable of transmitting light from a first side to a second side of the planar substrate <NUM>. Further, electrical interconnects may be optically transparent, in some embodiments. Moreover, a combination of the first and second arrays of active emitters <NUM>, <NUM> and the planar substrate <NUM> (e.g., along with the electrical interconnects) may be configured to be optically transparent, in some embodiments.

According to some embodiments, the multiview backlight <NUM> may further comprise a broad-angle backlight adjacent to the planar substrate <NUM>. The broad-angle backlight may be configured to provide broad-angle emitted light. Further, a combination of the first and second arrays of active emitters <NUM>, <NUM> and the planar substrate <NUM> may be configured to be transparent to the broad-angle emitted light, according to various embodiments.

<FIG> illustrates a cross-sectional view of a multiview backlight <NUM> including a broad-angle backlight <NUM> in an example, according to an embodiment consistent with the principles described herein. In particular, <FIG> illustrates the broad-angle backlight <NUM> adjacent to a surface of the planar substrate <NUM> with active emitters <NUM>, <NUM> arranged on an opposite surface. <FIG> further illustrates an array of light valves <NUM> adjacent to the opposite surface of the planar substrate <NUM>.

As illustrated on a left side of <FIG>, a multiview image (MULTIVIEW) may be provided using the multiview backlight <NUM> by activating the active emitters <NUM>, <NUM> to provide directional light beams <NUM>, e.g., one or both of directional light beams <NUM>', <NUM>", as variously described and illustrated above. Alternatively, as illustrated on a right side of <FIG>, a two-dimensional (2D) image may be provided by inactivating the active emitters <NUM>, <NUM> and activating the broad-angle backlight <NUM> to provide broad-angle emitted light <NUM> to the array of light valves <NUM>. As such, the multiview backlight <NUM> including the broad-angle backlight <NUM> and the planar substrate <NUM> configured to be transparent may be used to implement an electronic display that may be switched between displaying a multiview image and displaying a 2D image, according to various embodiments. Herein, active emitters <NUM>, <NUM> are illustrated as being activated by using crosshatching, while active emitters <NUM>, <NUM> without crosshatching represent an inactivated state or condition.

In accordance with some embodiments of the principles described herein, a multiview display is provided. The multiview display is configured to display a multiview image, according to various embodiments. Further, an image resolution of the multiview image is configured to be dynamically selectable according to an operational mode, according to various embodiments. In some embodiments, image resolution and a number of different views of the multiview image are dynamically selectable.

<FIG> illustrates a block diagram of a multiview display <NUM> in an example, according to an embodiment consistent with the principles described herein. As illustrated, the multiview display <NUM> comprises a first active emitter array <NUM>. The first active emitter array <NUM> is configured to provide directional light beams <NUM> having directions corresponding to view directions of the multiview image. In particular, each active emitter of the first active emitter array <NUM> is configured to provide a plurality of the directional light beams <NUM>, directional light beams <NUM> of the directional light beam plurality provided by the active emitter having different directions from one another and further having directions of or corresponding to the view directions.

The multiview view display <NUM> illustrated in <FIG> further comprises a second active emitter array <NUM>, the second active emitter array <NUM> being interleaved with the first active emitter array <NUM> on a surface of a substrate <NUM>. As with the first active emitter array <NUM>, the second active emitter array <NUM> is configured to provide directional light beams <NUM> having directions corresponding to the view directions of the multiview image. In particular, each active emitter of the second active emitter array <NUM> is configured to provide a plurality of the directional light beams <NUM>, directional light beams <NUM> of the directional light beam plurality provided by the active emitter having different directions from one another and further having directions of or corresponding to the view directions. Further, the directions of the directional light beams <NUM> provided by the second active emitter array may be substantially similar to the directions of the directional light beams <NUM> provided by the first active emitter array <NUM>.

As illustrated in <FIG>, the multiview display <NUM> further comprises an array of light valves <NUM>. The array of light valves <NUM> is configured to modulate the directional light beams <NUM> provided by one or both of the first and second active emitter arrays <NUM>, <NUM>. In particular, the array of light valves is configured to modulate the directional light beams <NUM> to display the multiview image, according to various embodiments.

In some embodiments, the first active emitter array <NUM> may be substantially similar to the first array of active emitters <NUM>, described above with respect to the multiview backlight <NUM>. In some embodiments, the second active emitter array <NUM> may be substantially similar to the second array of active emitters <NUM>, also of the above-described multiview backlight <NUM>. In particular, in some embodiments, a size of an active emitter of the first and second active emitter arrays <NUM>, <NUM> is commensurate to a size of a light valve of the array of light valves <NUM>. In some embodiments, a shape of the active emitter is comparable to a shape of a multiview pixel of the multiview display <NUM>. Further, active emitters of the first and second active emitter arrays <NUM>, <NUM> may comprise one or both of a micro light emitting diode (µLED) and an organic light emitting diode (OLED), in some embodiments. Further, the substrate <NUM> on which the first and second active emitter arrays <NUM>, <NUM> are located may be optically transparent, in some embodiments.

According to some embodiments, image resolution of the multiview image displayed by multiview display <NUM> may have a first value in a first operational mode and a second value in a second operational mode. In particular, the first operational mode may comprise the first active emitter array <NUM> being activated to provide the directional light beams <NUM> and the second active emitter being inactivated. The first operational mode may be configured to provide the multiview image having a first image resolution.

In some embodiments, the second operational mode may comprise both the first active emitter array <NUM> and the second active emitter array being activated to simultaneously provide the directional light beams <NUM>. The second operational mode may be configured to provide the multiview image having a second image resolution, where the second image resolution is greater than the first image resolution, according to some embodiments. For example, the first operational mode may be substantially similar to the first mode (Mode <NUM>) of the multiview backlight <NUM>, while the second operational mode may be substantially similar to the second mode (Mode <NUM>) of the multiview backlight <NUM>, as described above with reference to <FIG> and <FIG>, respectively. Selecting between the first operational mode and the second operational mode may provide dynamic selection of the image resolution albeit with a concomitant change in a number of views of the multiview image, according to various embodiments (e.g., also as described above).

In other embodiments, the second operational mode may comprise the first active emitter array <NUM> being activated to provide the directional light beams <NUM> during a first time interval and the second active emitter array <NUM> being activated to provide the directional light beams <NUM> during a second time interval, the first and second time intervals being alternating, sequential time intervals. For example, the second operational mode may be substantially similar to the light valve array time-multiplexing described above with respect to the multiview backlight <NUM> with reference to <FIG> and <FIG>. As above, selecting between the first operational mode and the second operational mode may provide dynamic selection of the image resolution (e.g., with and without using time-multiplexing), according to various embodiments.

In some embodiments (not illustrated), the multiview display <NUM> may further comprise a broad-angle backlight configured to provide broad-angle emitted light. According to various embodiments, the broad-angle backlight may be located adjacent to another surface of the substrate opposite to the surface on which the first and second active emitter arrays <NUM>, <NUM> are interleaved. In some embodiments, the broad-angle backlight may be substantially similar to the broad-angle backlight <NUM> of the multiview backlight <NUM>, illustrated and described with respect to <FIG>. In particular, a combination of the first and second active emitter arrays <NUM>, <NUM> and the substrate <NUM> may be configured to be transparent to the broad-angle emitted light, according to some embodiments.

In accordance with some embodiments of the principles described herein, a method of multiview backlight operation is provided. <FIG> illustrates a flow chart of a method <NUM> of multiview backlight operation in an example, according to an embodiment of the principles described herein. The method <NUM> of multiview backlight operation illustrated in <FIG> comprises emitting <NUM> a first plurality of directional light beams using a first array of active emitters. In particular, directional light beams of the first plurality of directional light beams have directions corresponding to view directions of a multiview image, according to various embodiments. In some embodiments, the first array of active emitters may be substantially similar to the first array of active emitters <NUM>, described above with respect to the multiview backlight <NUM>.

The method <NUM> illustrated in <FIG> further comprises emitting <NUM> a second plurality of directional light beams using a second array of active emitters interleaved with active emitters of the first active emitter array. In particular, directional light beams of the second plurality of directional light beams are emitted having directions corresponding to the view directions of the multiview image. In some embodiments, the second array of active emitters may be substantially similar to the second array of active emitters <NUM>, of the above-described multiview backlight <NUM>.

According to various embodiments, an active emitter of one or both of the first and second active emitter arrays may have a size comparable to a size of a view pixel of a multiview display used to display the multiview image. For example, the view pixel may correspond to a light valve of the light valve array used to modulate the directional light beams and the active emitter may have a size corresponding to a size or a distance between light valves of the light valve array. In an embodiment according to the invention, the comparable size of the active emitter is between one half (<NUM>) and two times (2X) the view pixel size.

In some embodiments, as illustrated in <FIG>, the method <NUM> of multiview backlight operation further comprises modulating <NUM> one or both of the first plurality of directional light beams and the second plurality of light beams using an array of light valves to display the multiview image. In some embodiments, the array of light valves may be substantially similar to the array of light valves <NUM>, <NUM>, described above with respect to either the multiview backlight <NUM> or the multiview display <NUM>. In some embodiments, a set of light valves of the array of light valves may correspond to a multiview pixel of a multiview display, while an individual light valve may correspond to a view pixel.

In some embodiments, emitting <NUM> the first plurality of light beams may be performed during a first time interval and emitting <NUM> the second plurality of light beams is performed during a second time interval, the first and second time intervals alternating in a time sequential manner. These embodiments may be used when multiplexing the array of light valves, as described above in conjunction with the multiview backlight <NUM>, with reference to <FIG>.

In other embodiments, emitting <NUM> the first plurality of directional light beams may be performed during a first operational mode. Further, both emitting <NUM> the first plurality of directional light beams and emitting <NUM> the second plurality of light beams may be performed during a second operational mode. These embodiments may be used to provide selection between a first image resolution and a second image resolution of the multiview image, as described above in conjunction with the multiview backlight <NUM>, with reference to <FIG>.

Claim 1:
A multiview display comprising multiview pixels (<NUM>), each multiview pixel comprising a set of view pixels, each view pixel corresponding to a respective different view direction (<NUM>) of the multiview display, and a multiview backlight, wherein the multiview backlight comprises:
a first array of active emitters (<NUM>) spaced apart from one another, an active emitter of the first array of active emitters (<NUM>) being configured to provide a first plurality of directional light beams (<NUM>') having directions corresponding to the view directions of the multiview display; and
a second array of active emitters (<NUM>) interleaved between active emitters of the first array of active emitters (<NUM>), an active emitter of the second array of active emitters (<NUM>) being configured to provide a second plurality of directional light beams (<NUM>") having directions corresponding to the view directions of the multiview display,
wherein the active emitters of the first and second active emitter arrays (<NUM>, <NUM>) have a size (s) between one half and two times the size (S) of a view pixel of the multiview display.