Display system including layer with diffractive and non-diffractive regions

Abstract

A display system includes a display region including a plurality of pixels, and a light diffractive layer adjacent the display region. Each pixel includes non-overlapping first and second pluralities of subpixels, each including at least three different subpixels. The subpixels define non-overlapping first and second intra-pixel regions therebetween for each pixel. The pixels define an inter-pixel region therebetween. The subpixels and the first intra-pixel region define a first combined region, and the second intra-pixel regions and the inter-pixel regions define a second combined region. The light diffractive layer includes light non-diffractive and diffractive regions aligned with the respective first and second combined regions. The light diffractive layer can non-diffractively transmit light from some of the subpixels for some emission directions while diffractively transmitting light from other subpixels and / or for other emission directions. A luminance profile of the transmitted light can be symmetric about at least one plane.

Description

[0001] PA102563W002

[0002] DISPLAY SYSTEM INCLUDING LAYER WITH DIFFRACTIVE AND

[0003] NON-DIFFRACTIVE REGIONS

[0004] TECHNICAL FIELD

[0005] The present description relates generally to display systems.

[0006] BACKGROUND

[0007] A display system can include a micro-light emitting diode (micro-LED) display panel.

[0008] SUMMARY

[0009] In some aspects, a display system includes a display region including a plurality of pixels, and a light diffractive layer adjacent the display region. Each pixel includes nonoverlapping first and second pluralities of subpixels, where each of the first and second pluralities includes at least three different subpixels. The subpixels define non-overlapping first and second intra-pixel regions therebetween for each pixel. The pixels define an inter-pixel region therebetween. The subpixels and the first intra-pixel region define a first combined region, and the second intra-pixel regions and the inter-pixel regions define a second combined region. The light diffractive layer includes light non-diffractive and diffractive regions aligned with the respective first and second combined regions. The light diffractive layer can non-diffractively transmit light from some subpixels for some emission directions while diffractively transmitting light from other subpixels and / or for other emission directions. An intensity or luminance profile of the transmitted light can be symmetric about at least one plane.

[0010] In some aspects, the present description provides a display system including a display region including a plurality of pixels configured to form an image thereacross for viewing by a viewer; and a light diffractive layer configured to be between the viewer and the display region and disposed substantially parallel to, and spaced apart along a thickness direction of the display system from, the display region. Each pixel includes nonoverlapping first and second pluralities of subpixels where each of the first and second pluralities includes at least three different subpixels having at least three different emission spectra. The subpixels define non-overlapping first and second intra-pixel regions therebetween for each pixel. The pixels define an inter-pixel region therebetween. Each of the first and second intra- pixel regions and the inter-pixel region is devoid of any light emitting subpixel. The subpixels and the first intra-pixel region define a first combined region, and the second intra-pixel regions and the interpixel regions define a second combined region. The light diffractive layer includes a light diffractive region configured to diffract light and a light non-diffractive region not configured to diffract light. The light non-diffractive and diffractive regions of the light diffractive layer are aligned, and substantially coextensive in length and width, with the respective first and second combined regions, such that for each pixel, for a first light emission angle relative to the thickness direction of greater than about 10 degrees and a second light emission angle relative to the thickness direction of less than about -10 degrees, and for first and second planes orthogonal to one another and parallel to the thickness direction: for a first subpixel of the first plurality of subpixels, light emitted by the first subpixel in the first plane at the first emission angle is diffractively transmitted by the light diffractive region of the light diffractive layer, and light emitted by the first subpixel in the first plane at the second emission angle is non-diffractively transmitted by the light non-diffractive region of the light diffractive layer; for a second subpixel of the second plurality of subpixels, where the first and second subpixels have a substantially same first emission spectrum, light emitted by the second subpixel in the first plane at the second emission angle is diffractively transmitted by the light diffractive region of the light diffractive layer, and light emitted by the second subpixel in the first plane at the first emission angle is non-diffractively transmitted by the light non-diffractive region of the light diffractive layer; and for each subpixel of each of the first and second pluralities of subpixels, light emitted by the subpixel in the second plane at the each of the first and second emission angles is diffractively transmitted by the light diffractive region of the light diffractive layer.

[0011] In some aspects, the present description provides a display system including a display region configured to form an image thereacross for viewing by a viewer and including a plurality of pixels defining a light emitting region configured to emit light and a light non-emitting region not configured to emit light; and a light diffractive layer comprising a light diffractive region configured to diffract light and a light non-diffractive region not configured to diffract light. Each pixel includes nonoverlapping first and second pluralities of subpixels where each of the first and second pluralities of subpixels includes red, green and blue subpixels. The light diffractive layer is disposed on, and spaced apart along a thickness direction of the display system from, the display region, such that in atop plan view, the light diffractive region covers more than 60% of the light non-emitting region and less than 40% of the light emitting region. The pixels and the subpixels of the first and second pluralities of subpixels are arranged so that for the red subpixels, for the green subpixels, and for the blue subpixels, light emitted by the subpixels is transmitted by the light diffractive layer and exits the display system in air toward the viewer, at least some of the emitted light being diffractively transmitted by the light diffractive layer, such that: in a first plane parallel to the thickness direction, the exiting light has a first luminance profile as a function of light propagation angle relative to the thickness direction that is substantially symmetric about a second plane parallel to the thickness direction and orthogonal to the first plane at least for light propagation angle relative to the thickness direction in a range of about -50 degrees to about 50 degrees; and in the second plane, the exiting light has a second luminance profile as a function of light propagation angle relative to the thickness direction that is substantially symmetric about the first plane at least for light propagation angle relative to the thickness direction in a range of about -50 degrees to about 50 degrees.

[0012] These and other aspects will be apparent from the following detailed description. In no event, however, should this brief summary be construed to limit the claimable subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIGS. 1A-1B are schematic cross-sectional views of a portion of a display system including a diffractive layer, according to some embodiments.

[0014] FIG. 1C is a schematic cross-sectional view of a portion of a comparative display system corresponding to the display system of FIGS. 1A-1B without the diffractive layer.

[0015] FIGS. 2-5 are schematic top plan views of portions of display systems including diffractive layers, according to some embodiments.

[0016] FIGS. 6-7 are schematic top plan views of pixels, according to some embodiments.

[0017] FIG. 8 is a schematic plot of emission spectra of subpixels, according to some embodiments.

[0018] FIG. 9 shows a luminance profde plot for a display system including a diffractive layer similar to the diffractive layer schematically illustrated in FIG. 4, according to some embodiments.

[0019] FIGS. 10A-10B show luminance profile plots for a display system including a diffractive layer similar to the diffractive layer schematically illustrated in FIG. 5, according to some embodiments.

[0020] DETAILED DESCRIPTION

[0021] In the following description, reference is made to the accompanying drawings that form a part hereof and in which various embodiments are shown by way of illustration. The drawings are not necessarily to scale. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present description. The following detailed description, therefore, is not to be taken in a limiting sense.

[0022] A display system can emit light along an axial direction towards a viewer and along off-axis directions. In some cases, it is desired that at least some of the off-axis light in at least one plane (e.g., in a vertical plane) is redirected substantially along the axial direction to increase the axial luminance and the brightness experienced by the viewer. It is often desired that the light output having the increase in axial brightness have a desired (e.g., symmetric) luminance profile as a function of light propagation angle. It has been found, according to some embodiments, that suitable arrangements of subpixels with suitably patterned light diffractive layers described herein can be used to achieve improved axial brightness with a desired luminance profile. The suitably patterned light diffractive layers can include non-diffractive regions covering light emitting regions of a display and covering some, but not other, portions of light non-emitting regions within pixels, and the suitable arrangement of subpixels can include a symmetry under interchange of certain subpixels, according to some embodiments. Luminance can be measured using standard photometric techniques where the CIE 1931 tristimulus y function may be used as the photopic luminous efficiency function for converting radiant quantities to luminous quantities.

[0023] Diffraction gratings have been used with displays for other purposes. A diffraction grating can be placed over an organic light emitting diode (OLED) display panel to correct off-axis color shift as described in U.S. Pat. No. 10,991,765 (Freier et al.), for example. Diffractive structures can be disposed on emissive regions of an OLED device within an evanescent zone of the emissive regions to improve extraction of light that would otherwise be trapped in the OLED device as described in U.S. Pat. Appl. Pub. No. 2010 / 0110551 (Lamansky et al.), for example. In each of these cases, a diffractive layer is placed over an entire emissive layer of the OLED device. However, when a diffraction grating is placed over an entire emissive layer with the diffraction grating selected to provide a first order diffraction of at least some of the off-axis light into the axial direction, some of the light emitted by the pixels in the axial direction will be diffracted into off-axis directions so that the axial brightness is not substantially increased by redirecting the off-axis light. Diffraction gratings have also been used over light nonemitting regions of a display to increase axial efficiency of the display as described in International App. Pub. No. WO 2024 / 033838 (DeSutter et al.).

[0024] According to some embodiments of the present description, a light diffractive layer can be patterned to include light diffractive regions above some portion, but not some other portion (e.g., not above spaces between closest subpixels within a pixel), of a light non-emitting region of the display surface but not above the light emitting regions (e.g., subpixels) and this allows at least some of the off- axis light to be diffracted into (or close to) the axial direction substantially without diffracting the emitted axial light into non-axial directions, and it has been found, according to some embodiments, that the arrangement of subpixels can be selected to give desired properties (e.g., symmetry) of the luminance profile of light exiting the display. In some embodiments, this can result in significant improvement in axial luminance (e.g., by at least 10, 15, 20, 25, 30, 35, 40, 45, or even 50%) compared to a comparative display system that does not include the diffractive layer and / or compared to a display system that includes a diffractive layer with diffractive structures covering the entire display panel.

[0025] A display can include pixels where each pixel includes at least two sets of subpixels for redundancy. For example, a micro-light emitting diode (micro-LED) display panel can include such redundant subpixels since it has been difficult to reliably provide micro-LEDs without defects. However, it has been found that when redundant subpixels are included, placing a light diffractive layer above the display surface with non-diffractive regions over at least the subpixels and with diffractive regions over inter-pixel regions between the pixels can result in undesired properties of the luminance profile of the emitted light. For example, as described further elsewhere herein, it has been found that placing the non- diffractive regions only over the subpixels and spaces between closest adjacent subpixels when conventional subpixel layouts are utilized can result in an asymmetric luminance distribution (e.g., different for viewing angles to the right than for viewing angles to the left). However, it has been found, according to some embodiments, that the subpixel arrangement can be modified to restore the symmetry.

[0026] The luminance distribution can be normalized by any fixed value. For example, the normalized luminance distribution can be the luminance distribution divided by the value of the luminance distribution at 0 degrees relative to the normal or thickness direction of the display, or the normalized luminance distribution can be the luminance distribution divided by the value of a comparative luminance distribution at 0 degrees relative to the normal or thickness direction of the display, where the comparative luminance distribution is the luminance distribution of a comparative display system that has a same construction as the display system except that it does not include the light diffractive layer.

[0027] A pixel is a smallest addressable element forming a unit of an image in a display where the unit can produce the color gamut of the display. For example, a standard full (1080p) high definition display includes 1920 x 1080 pixels and a standard 4K display includes 3840 x 2160 pixels. A pixel typically includes at least three subpixels so that the pixel can produce the desired color gamut. When redundant subpixels are included, a pixel typically includes at least 6 subpixels (e.g., red, green, and blue subpixels of the first (primary) plurality of subpixels and red, green, and blue subpixels of the second (redundant) plurality of subpixels). Regions between the subpixels of a pixel may be referred to as intra-pixel regions and regions between pixels may be referred to as inter-pixel regions.

[0028] FIGS. 1A-1B are schematic cross-sectional views of a portion of a display system 100, according to some embodiments. FIG. 1C is a schematic cross-sectional view of a portion of a comparative display system 100C. FIGS. 2-5 are schematic top plan views of portions of display systems 100, 100', 100", 100"', according to some embodiments. The display system 100, 100', 100", 100'" includes a display region 101 including light emitting regions 110 (e.g., subpixels) and light non-emitting regions 120 (e.g., inter-pixel or intra-pixel non-emitting regions). The display system can include a (e.g., emissive) display layer 151 (see, e.g., FIGS. 1A-1B) including the display region 101. The display system 100, 100', 100", 100'" incudes a light diffractive layer 150, 150', 150", 150'". The comparative display system 100C corresponds to the display system 100 except that the comparative display system 100C does not include the light diffractive layer 150. The light diffractive layer 150, 150", 150'" includes a linear grating in display system 100 and the light diffractive layer 150' includes a two-dimensional grating in display system 100'. A linear grating or a two-dimensional grating may be used with the pixel layouts of any of these display systems. In FIG. 1A-1B, light 141, 142 emitted by the subpixel 110 in a first plane (yz- plane) at each of first and second emission angles al, a2 is diffractively transmitted (as respective transmitted light 141' and 142' at respective light propagation angles in air of al' and a2') by the light diffractive region 152 of the light diffractive layer 150, 150', 150", 150'"; and light 143, 144 emitted by the subpixel in the second plane (xz-plane) at each of the first and second emission angles al, a2 is non- diffractively transmitted (as respective transmitted light 143' and 144') through the light non-diffractive region 154 of the light diffractive layer 150, 150', 150", 150'". In some embodiments, light 140 emitted along an axial direction (z-direction) is non-diffractively transmitted (e.g., as transmitted light 140') through the light non-diffractive region 154. The light emission angles and the light propagation angles in air can be defined as positive when the direction of the light in the xz- or yz-plane projected onto the xy- plane is along the +x axis or the +y direction, respectively, and negative when the projection is along the -x or -y direction, respectively.

[0029] In some embodiments, a display system 100, 100', 100", 100'" includes a display region 101 including a plurality of pixels 105 configured to form an image 107 thereacross for viewing by a viewer 109. In some embodiments, each pixel can include nonoverlapping first and second pluralities 110a and 110b of subpixels 110. Each of the first and second pluralities 110a and 110b can include at least three different subpixels having at least three different emission spectra (see, e.g., FIGS. 6-8). The subpixels 110 define non-overlapping first and second intra-pixel regions 111 and 112 therebetween for each pixel. The pixels define inter-pixel regions (e.g., light non-emitting regions 120 excluding light non-emitting intra-pixel regions) therebetween. Each of the first and second intra-pixel regions 111 and 112 and the inter-pixel regions is devoid of any light emitting subpixel. Intra-pixel regions are generally regions within a pixel, while inter-pixel regions are between adjacent pixels. Each subpixel generally defines a light emitting region and since the first and second intra-pixel regions are defined to be between subpixels, the first and second intra-pixel regions are light non-emitting regions. Similarly, since the inter-pixel regions are defined to be between pixels, the inter-pixel regions are light non-emitting regions. The first intra-pixel regions 111 can be between adjacent subpixels arranged along a same row (along the x-direction) of a pixel, and the second intra-pixel regions 112 can be between adjacent rows of subpixels of a pixel. The subpixels 110 and the first intra-pixel region 111 define a first combined region (i.e., the first combined region is the combination of the subpixels 110 and the first intra-pixel regions 111), and the second intra-pixel regions 112 and the inter-pixel regions (e.g., light non-emitting regions 120 excluding light non-emitting intra-pixel regions) define a second combined region (i.e., the second combined region is a combination of the second intra-pixel regions 112 and the inter-pixel regions).

[0030] FIGS. 6-7 are schematic top plan views of pixels 105, according to some embodiments. The pixel 105 includes a first plurality 110a of subpixels 11 Or 1 , 1 lOgl, and 1 lObl (e.g., red, green, and blue subpixels) and a second plurality 110b of subpixels 110r2, 110g2, and 110b2 (e.g., red, green, and blue subpixels). In some embodiments, adjacent subpixels within pixels have an average center to center spacing Wc along a first direction (e.g., x-direction or y-direction), and an average spacing between adjacent pixels along the first direction is Wsl, where Wsl > Wc. In some embodiments, Wsl is at least 1.5, 2, 3, or 4 times Wc. The emitted light from red (e.g., HOrl, 110r2), green (e.g., l lOgl, 110g2), and blue (e.g., 110b 1 , 110b2) subpixels can include wavelengths in a visible wavelength range extending from about 400 nm to about 700 nm. For example, emitted light from blue subpixels can be blue light in a wavelength range of about 420 nm to about 490 nm, emitted light from green subpixels can be green light in a wavelength range of about 490 nm to about 590 nm, and emitted light from red subpixels can be red light in a wavelength range of about 590 nm to about 680 nm.

[0031] FIG. 8 is a schematic plot of emission spectra of subpixels, according to some embodiments. Emission spectra 200b, 200g, and 200r are schematically illustrated. In some embodiments, each of subpixels 1 lOrl and 110r2 have a substantially same (e.g., same, or nominally same, or same to within 10 or 5 percent variation) emission spectrum 200r (e.g., red), each of subpixels 1 lOgl and 110g2 have a substantially same emission spectrum 200g (e.g., green), and each of subpixels 1 lObl and 110b2 have a substantially same emission spectrum 200b (e.g., blue). The display system 100, 100', 100", 100"' includes a light diffractive layer 150, 150', 150", 150'" configured to be between the viewer 109 and the display region 101 and disposed substantially parallel (e.g., within 20, 15, 10, or 5 degrees of parallel or nominally parallel) to, and spaced apart along a thickness direction (z -direction) of the display system 100 (or a thickness direction of the light diffractive layer) from, the display region 101. The light diffractive layer 150, 150', 150", 150'" includes a light diffractive region 152 configured to diffract light and a light non-diffractive region 154 not configured to diffract light.

[0032] The light non-diffractive and diffractive regions of the light diffractive layer 150, 150', 150", 150'" can be aligned, and substantially coextensive in length and width, with the respective first and second combined regions, such that for each pixel, for a first light emission angle al relative to the thickness direction of greater than about 10 degrees (or greater than about 15 or 20 degrees) and a second light emission angle relative to the thickness direction of less than about -10 degrees (or less than about - 15 or -20 degrees), and for first and second planes (xz- and yz-planes) orthogonal to one another and parallel to the thickness direction (z-direction): for a first subpixel (e.g., 110b 1) of the first plurality of subpixels (e.g., 110a), light emitted by the first subpixel in the first plane (xz-plane) at the first emission angle al (e.g., along +x direction) is diffractively transmitted by the light diffractive region 152 of the light diffractive layer 150, 150', 150", 150'", and light emitted by the first subpixel in the first plane at the second emission angle a2 (e.g., along -x direction) is non-diffractively transmitted by the light non- diffractive region 154 of the light diffractive layer 150, 150', 150", 150'"; for a second subpixel (e.g., 110b2) of the second plurality of subpixels where the first and second subpixels have a substantially same first emission spectrum (e.g., 200b), light emitted by the second subpixel in the first plane at the second emission angle a2 is diffractively transmitted by the light diffractive region 152 of the light diffractive layer 150, 150', 150", 150'", and light emitted by the second subpixel in the first plane at the first emission angle al is non-diffractively transmitted by the light non-diffractive region 154 of the light diffractive layer 150, 150', 150", 150'"; and for each subpixel of each of the first and second pluralities of subpixels, light emitted by the subpixel in the second plane (yz-plane) at the each of the first and second emission angles al and a2 is diffractively transmitted by the light diffractive region 152 of the light diffractive layer 150, 150', 150", 150'". Whether or not light emitted by a subpixel is diffracted can be determined from inspection of the plan views of FIGS. 2-5, for example, based on whether or not a portion of the light diffractive region is intersected by the emitted light which can depend on how far the diffractive layer is from the pixels.

[0033] In some embodiments, for a third subpixel (e.g., a red subpixel) in the first plurality of subpixels and a fourth subpixel in the second plurality of subpixels where the third and fourth subpixels have a substantially same second emission spectrum (e.g., 200r) substantially different from the first emission spectrum: light emitted by the third subpixel in the first plane at the second emission angle a2 is diffractively transmitted by the light diffractive region 152 of the light diffractive layer 150, 150', 150", 150"', and light emitted by the third subpixel in the first plane at the first emission angle al is non- diffractively transmitted by the light non-diffractive region 154 of the light diffractive layer 150, 150', 150", 150'"; and light emitted by the fourth subpixel in the first plane at the first emission angle al is diffractively transmitted by the light diffractive region 152 of the light diffractive layer 150, 150', 150", 150'", and light emitted by the fourth subpixel in the first plane at the second emission angle a2 is non- diffractively transmitted by the light non-diffractive region 154 of the light diffractive layer 150, 150', 150", 150'". In some embodiments (see, e.g., FIG. 5), for a fifth subpixel (e.g., a green subpixel) in the first plurality of subpixels and a sixth subpixel in the second plurality of subpixels where the fifth and sixth subpixels having a substantially same third emission spectrum (e.g., 200g) substantially different from each of the first and second emission spectra: light emitted by the fifth subpixel in the first plane at the second emission angle a2 is diffractively transmitted by the light diffractive region 152 of the light diffractive layer 150, 150', 150", 150'", and light emitted by the fifth subpixel in the first plane at the first emission angle al is non-diffractively transmitted by the light non-diffractive region 154 of the light diffractive layer 150, 150', 150", 150'"; and light emitted by the sixth subpixel in the first plane at the first emission angle al is diffractively transmitted by the light diffractive region 152 of the light diffractive layer 150, 150', 150", 150'", and light emitted by the sixth subpixel in the first plane at the second emission angle a2 is non-diffractively transmitted by the light non-diffractive region 154 of the light diffractive layer 150, 150', 150", 150'". In some embodiments (see, e.g., FIG. 4), for each of a fifth subpixel (e.g., a green subpixel) in the first plurality of subpixels and a sixth subpixel in the second plurality of subpixels where the fifth and sixth subpixels have a substantially same third emission spectrum (e.g., 200g) substantially different from each of the first and second emission spectra, and for each of the first and second emission angles al and a2, light emitted by the subpixel in the first plane is non-diffractively transmitted by the light non-diffractive region 154 of the light diffractive layer 150, 150', 150", 150"'.

[0034] In some embodiments, the first light emission angle al relative to the thickness direction is greater than about 15 degrees or greater than about 20 degrees. In some embodiments, the first light emission angle al is less than about 40 degrees or less than about 35 degrees. In some embodiments, the second light emission angle a2 relative to the thickness direction is less than about -15 degrees or less than about -20 degrees. In some embodiments, the second light emission angle a2 is greater than about - 40 degrees or greater than about -35 degrees. For example, in some embodiments, 40 degrees > al > 10 degrees and -40 degrees < a2 < -10 degrees. In some embodiments, a2 is about -al.

[0035] Layers or elements can be described as substantially coextensive with each other in length and width if greater than 50% of the length and width of each layer or element is coextensive with greater than 50% of the length and width of each other layer or element. In some embodiments, for layers or elements described as substantially coextensive with each other in length and width, at least about 60%, or at least about 70%, or at least about 80%, or at least about 90%, or at least about 95% of each layer or element is coextensive in length and width with at least about 60%, or at least about 70%, or at least about 80%, or at least about 90%, or at least about 95% of the length and width of each other layer or element.

[0036] In some embodiments, at least 30%, or 35%, or 40%, or 45%, or 50%, or 55%, or 60%, or 65%, or 70%, or 75%, or 80%, or 85%, or 90%, or 95% of a total area of the light diffractive region 152 of the light diffractive layer 150, 150', 150", 150"' overlaps at least 30%, or 35%, or 40%, or 45%, or 50%, or 55%, or 60%, or 65%, or 70%, or 75%, or 80%, or 85%, or 90%, or 95% of a total area of the light nonemitting region 120 of the display region 101. For example, in some embodiments, at least 50% of a total area of the light diffractive region 152 of the light diffractive layer overlaps at least 50% of a total area of the light non-emitting region 120 of the display region 101, or at least 75% of a total area of the light diffractive region 152 of the light diffractive layer overlaps at least 75% of a total area of the light nonemitting region 120 of the display region 101, or at least 90% of a total area of the light diffractive region 152 of the light diffractive layer overlaps at least 80% of a total area of the light non-emitting region 120 of the display region 101. In some embodiments, at least 30%, or 35%, or 40%, or 45%, or 50%, or 55%, or 60%, or 65%, or 70%, or 75%, or 80%, or 85%, or 90%, or 95% of a total area of the light non- diffractive region 154 of the light diffractive layer overlaps at least 30%, or 35%, or 40%, or 45%, or 50%, or 55%, or 60%, or 65%, or 70%, or 75%, or 80%, or 85%, or 90%, or 95% of a total area of the light emitting region 110 of the display region 101. For example, in some embodiments, at least 50% of a total area of the light non-diffractive region 154 of the light diffractive layer overlaps at least 50% of a total area of the light emitting region 110 of the display region 101, or at least 75% of a total area of the light non-diffractive region 154 of the light diffractive layer overlaps at least 75% of a total area of the light emitting region 110 of the display region 101, or at least 90% of a total area of the light non- diffractive region 154 of the light diffractive layer overlaps at least 80% of a total area of the light emitting region 110 of the display region 101.

[0037] In some embodiments (see, e.g., FIGS. 2-4), for each pixel 105, the first and second pluralities of subpixels 110a and 110b are arranged into respective first and second rows 130a and 130b of the subpixels extending along a same in-plane first direction (x-direction) and spaced apart along an in-plane second direction (y-direction) orthogonal to the first direction, where the subpixels in the first row 130a are arranged in a first sequence of red, green and blue subpixels and the subpixels in the second row 130b are arranged in a second sequence of red, green, and blue subpixels opposite to the first sequence. In some embodiments, for each of the first and second rows 130a and 130b of each of the pixels, the first intra-pixel region 111 includes spaces between the subpixels of the row.

[0038] In some embodiments (see, e.g., FIG. 5), for each pixel 105, the first and second pluralities of subpixels 110a and 110b are arranged into respective first and second rows 130a and 130b of the subpixels extending along a same in-plane first direction (y-direction) and spaced apart along an in-plane second direction (x-direction) orthogonal to the first direction, where the subpixels of each of the first and second rows 130a and 130b are arranged in a same sequence of red, green, and blue subpixels, and where the subpixels in the first and second rows 130a and 130b form pairs of adjacent subpixels such that for each pair, the subpixels of the pair have a substantially same emission spectrum. In some embodiments, for each of the pairs of adjacent subpixels, the first intra-pixel region 111 includes a space between the subpixels of the pair. In some embodiments, for each of the pairs of adjacent subpixels and for the subpixel of the pair from the first row 130a, the subpixel of the pair from the second row 130b is the subpixel of the second row 130b that is closest to the subpixel of the pair from the first row 130a.

[0039] In some embodiments, an average spacing SI (see, e.g., FIGS. 1A-1B) between the light diffractive layer 150, 150', 150", 150"' and the display region 101 is greater than about 10, or 15, or 20, or 30, or 40, or 50, or 100, or 150, or 200, or 250, or 300, or 350, or 400, or 400, or 500 microns and less than about 5000 microns. In some embodiments, the average spacing SI is less than about 4500, or 4000, or 3500, or 3000, or 2500, or 2000, or 1500, or 1000, or 500, or 200, or 150 microns. In some embodiments, the average spacing SI is in a range of about 10 microns to about 5000 microns, or about 20 microns to about 4000 microns, or about 30 microns to about 2000 microns, or about 35 microns to about 200 microns, or about 40 microns to about 150 microns, for example. The spacing SI can be provided by including a layer between the light diffractive layer 150, 150', 150", 150'" and the display region 101 where the layer can be a (e.g., thin film) encapsulant layer and / or an (e.g., optically clear) adhesive layer, or a glass layer or another display layer such as a polarizer or touch sensor layer, for example.

[0040] The light diffractive layer 150, 150', 150", 150'" can include first and second layers 150a and 150b (see, e.g., FIGS. 1A-1B). In some embodiments, the first layer 150a is formed on a substrate (e.g., a polymeric substrate or another layer) using a cast and cure process where diffractive structures are fabricated from a tool by casting a polymerizable resin composition onto the substrate and curing the resin in contact with a structured surface of the tool. Such cast and cure methods are described in U.S. Pat. Nos. 5,175,030 (Lu et al.) and 5,183,597 (Lu) and in U.S. Pat. Appl. Pub. No. 2012 / 0064296 (Walker, JR. et al.), for example. The structured surface of the tool can be selected to define light diffractive regions and light non-diffractive regions, or the tool can define light diffraction structures throughout the structured surface of the first layer 150a and then portions of the light diffractive structures can be filled in in a subsequent coating step with a same material as used to form the first layer 150a in the cast and cure process, or a different material with a similar refractive index (e.g., substantially closer in refractive index to the cast and cure material than to the material of the second layer 150b), in order to define light non-diffractive regions. The second layer 150b can be a (e.g., planarizing) backfill layer coated over the structured surface defined in first layer 150a. The first and second layers 150a and 150b typically have different refractive indices na and nb, respectively, for at least a same first wavelength (e.g., about 550 nm) in a wavelength range of 420 nm to 680 nm, for example. In some embodiments, the difference nb-na can be at least about 0.03, 0.05, 0.07, 0.09, or 0.1, for example, for at least the first wavelength. In some such embodiments, or in other embodiments, the difference nb-na can be up to about 2, 1.5, 1, 0.8, 0.6, 0.5, or 0.4, for example, for at least the first wavelength. In some embodiments, the non-diffractive regions include a structured interface and the difference in refractive index across the structured interface can be less than about 0.08, 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01, for example, for at least the first wavelength. In some embodiments, the diffractive layer 150, 150', 150", 150"' includes more than 2 materials or layers. For example, the diffractive layer 150, 150', 150", 150'" can include a thin (e.g., substantially thinner than the grating height) overcoat layer at the grating interface that may have a high refractive index (e.g., the refractive index can be at least about 2, such as a refractive index of about 2.5, for example) for at least the first wavelength. In some embodiments, at the first wavelength, the layer 150a has a refractive index of about 1.4 to about 1.55, and the layer 150b has a refractive index of about 1.6, 1.65, 1.7, or 1.75 to about 1.85. The average spacing SI can be in a range of about 20 to 1000 microns, the layer 150a can have a thickness of about 10 to 20 microns, and the layer 150b can have a thickness of about 5 to about 15 microns, for example. The average spacing SI may be in a range of about 20 to about 30 microns in cell phone applications, for example, and may be in a range of about 30, 35, 40, 45, 50, 60, 70, 80, or 90 microns to about 1000 microns in television applications, for example. In some embodiments, the light diffractive layer 150, 150', 150", 150'" is formed separately and then disposed on the layer 151, which can be or include an emissive layer, with an optional air gap therebetween or the light diffractive layer 150, 150', 150", 150'" can be laminated to the emissive layer.

[0041] The light diffractive and light non-diffractive regions 152 and 154 can be patterned by any other suitable means. In some embodiments, the light diffractive and light non-diffractive regions 152 and 154 can be patterned by inkjet printing, photolithography, masking, or other suitable patterning technologies. In some embodiments, the patterning technology determines the placement of an index matching (e.g., difference in refractive index (e.g., at 550 nm) less than about 0.08, 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01, for example) material to define the location of the light non-diffractive region 154. In some embodiments, the patterning technology determines the placement of an index mismatching (e.g., difference in refractive index (e.g., at 550 nm) at least about 0.03, 0.05, 0.07, 0.09, or 0.1 for example) material to define the light diffractive regions 152. In some embodiments, the patterning technology defines the exposure region over which the grating is preferentially fabricated or removed by, for example, etching or scribing. In some embodiments, the light diffractive layer can be formed on the surface of another layer already present in the display system by etching or scribing where the process of etching or scribing is patterned as to define the light diffractive and light non-diffractive regions 152 and 154. Other methods of patterning known in the art may alternatively be utilized.

[0042] In some embodiments, the pixels 105 are arranged into rows 130 of pixels extending along an inplane first direction (e.g., x-direction in FIGS. 2-4 or y-direction in FIG. 5) where each row of pixels includes a row 130a of subpixels 110 of the first plurality of subpixels 110a and a row 130b of subpixels 110 of the second plurality of subpixels 110b. The rows 130 can be spaced apart from one another along an in-plane second direction (e.g., y-direction or x-direction) orthogonal to the first direction (e.g., x- direction or y-direction). In some embodiments, an average spacing Ws2a between rows 130a, 130b of subpixels within rows 130 of pixels is less than an average spacing Ws2b between adjacent rows of pixels. In some embodiments, Ws2a is less than 0.9, 0.8, 0.7, 0.6, or 0.5 times W2sb. In some embodiments, Ws2a is greater than an average subpixel length along the second direction. In some embodiments, the pixels 105 have an average width Wpl along the first direction and an average spacing between adjacent pixels along the first direction is Wsl. The average width Wpl plus the average spacing Wsl can define an average pixel pitch along the first direction which relates to the resolution of the display. In some embodiments, Wsl > Wpl. In some embodiments, 5 (or 4, or 3, or 2) times Wpl > Wsl > Wpl. In some embodiments, Wsl < Wpl. In some embodiments, Wsl and Wpl are about equal.

[0043] In some embodiments, the light diffractive region 152 includes a plurality of substantially parallel linear diffractive elements extending along the first direction (e.g., x-direction) and arranged along an in-plane second direction (e.g., y-direction) orthogonal to the first direction (see, e.g., FIGS. 2 and 4). In some embodiments, the light diffractive region 152 includes a plurality of substantially parallel linear diffractive elements extending along an in-plane second direction (e.g., y-direction) and arranged along the first direction (e.g., x-direction), where the second direction is orthogonal to the first direction (see, e.g., FIG. 5). In some embodiments, the light diffractive region 152 includes a two-dimensional grating (see, e.g., FIG. 3) including a plurality of diffractive elements arranged along each of two orthogonal in-plane directions (e.g., the first direction (x-direction) and an in-plane second direction (y- direction) orthogonal to the first direction).

[0044] As is known in the art, the geometry of a grating and the refractive index difference across the grating can be selected to provide a desired first order diffraction peak in a desired direction. In some embodiments, the grating has a periodic pattern with a period in a range from about 0.2 to about 5 microns, or about 0.3 to about 3.5 microns, or about 0.4 to about 3 microns, or about 0.5 to about 2.5 microns, or about 0.6 to about 2 microns. In some embodiments, the diffractive elements form an irregular pattern having an average spacing or pitch in any of the ranges described for the period of the periodic grating. In some embodiments, the diffractive elements has an average height in a range from about 0.05 to about 3.5 microns, or about 0. 1 to about 3.25 microns, or about 0.2 to about 3 microns, or about 0.3 to about 2.75 microns, or about 0.4 to about 2.5 microns, or from about 0.5 to about 2.25 microns, or from about 0.6 to about 2 microns, or from about 0.7 to about 1.75 microns, or from about 0.8 to about 1.5 microns, or from about 0.8 to about 1.25 microns, or from about 0.8 to about 1 microns.

[0045] As is known in the art, light diffractive structures of a light diffractive layer can be selected to diffract light into desired directions when the light is transmitted through the light diffractive layer. The light diffractive region 152 can include any suitable diffractive structures that result in light diffraction into suitable directions. For example, the light diffractive region 152 can include phase gratings, amplitude gratings, one-dimensional gratings (e.g., including substantially parallel linear diffractive elements), two-dimensional gratings (e.g., on a square, rectangular, or hexagonal lattice), subwavelength structures, metasurface structures, and / or other diffractive structures known in the art. In some embodiments, the light diffractive structures form a grating, and the geometry and refractive indices of the light diffractive structures can be related to the desired directions by a diffraction grating equation, for example. Illustrative diffractive structures described by diffraction grating equations can be found in “Design and fabrication of binary slanted surface -relief gratings for a planar optical interconnection”, Miller et al., Applied Optics, Vol. 36, No. 23, 1997 and “Formulation for stable and efficient implementation of the rigorous coupled-wave analysis of binary gratings”, Moharam et al., J. Opt. Soc. Am. A, Vol. 12, No. 5, 1995, for example. In some embodiments, the light diffractive structures form a metasurface (which can be considered to be a diffractive surface) that provides suitable steering into desired directions. Illustrative metasurfaces for beam steering are described in U.S. Pat. Appl. Publ. No., 2021 / 0109364 (Aieta et al.) and “Free-Form Diffractive Metagrating Design Based on Generative Adversarial Networks”, Jiang et al., ACS Nano, 13, 8872-8878, 2019, for example. The geometry of the diffractive elements can be selected, in part, based on the geometry of the pixel and subpixel layout and / or in part on desired luminance profiles along a horizontal direction (e.g., in xz-plane) and / or along a vertical direction (e.g., in yz -plane).

[0046] FIG. 9 shows normalized luminance profile plots for display systems including diffractive layers with linear diffractive elements, according to some embodiments. Results are shown for green subpixels illuminated and for a horizontal (x-direction) viewing profile with a pixel layout (with symmetric arrangement of subpixels) and linear diffractive elements arrangement as generally illustrated in FIG. 4 (Example 1). Results for a display with the same pixel arrangement but without diffractive elements (Control 1) and results for a comparative display (Aligned) with aligned subpixels (with the order reversed in row 130b from that shown in FIG. 4 so that for each subpixel color, the subpixels of the color are directly above one another) are also shown.

[0047] FIGS. 10A-10B show results for green subpixels (or middle subpixels referring to the middle row of subpixels within a pixel) illuminated and for horizontal (x-direction) and vertical (y-direction) viewing profdes with a pixel layout and linear diffractive elements arranged as generally illustrated in FIG. 5 (Example 2), but with Wsl selected so that a distance between pixels in the y-direction (Wsl) was approximately equal to a distance along the y-direction of subpixels within a pixel. Results for a display with the same pixel arrangement but without diffractive elements (Control 2) are also shown.

[0048] The luminance profdes of FIGS. 9 and 10A-10B were determined using conventional ray tracing techniques. The diffractive gratings were simulated via rigorous coupled wave analysis (RCWA) and the scattering information was then compiled for utilization during the ray trace. The linear diffractive elements were modeled as being arranged at an 800 nm pitch with 850 nm height, 500 nm ridge width, and low and high refractive indices of 1.52 and 1.72, respectively. The grating was disposed with a spacing SI of 80 microns. Normalized luminance was determined as the luminance divided by the luminance at a polar angle of zero degrees of a comparative display system having a same construction as the display system except that that the light diffractive layer was not included in the comparative display system (e.g., in FIGS. 1A-1B, the comparative display system can correspond to the display layer 151 without the light diffractive layer 150). In each case, the luminance of the display system was normalized by the luminance of the comparative display system with the same subpixels illuminated (e.g., only the subpixels of a given color).

[0049] In some embodiments, a display system 100, 100', 100", 100"' includes a display region 101 configured to form an image 107 thereacross for viewing by a viewer 109 and including a plurality of pixels 105 defining a light emitting region 110 configured to emit light and a light non-emitting region 120 not configured to emit light, where each pixel includes nonoverlapping first and second pluralities 110a and 110b of subpixels, and where each of the first and second pluralities of subpixels includes red, green and blue subpixels; and a light diffractive layer 150, 150', 150", 150'" including a light diffractive region 152 configured to diffract light and a light non-diffractive region 154 not configured to diffract light, where the light diffractive layer 150, 150', 150", 150'" is disposed on, and spaced apart along a thickness direction (z -direction) of the display system from, the display region 101, such that in a top plan view, the light diffractive region 152 covers more than 60% of the light non-emitting region 120 and less than 40% of the light emitting region 110. In some embodiments, the light diffractive region 152 covers more than 65, 70, 75, 80, 85, 90, or 95 percent of the light non-emitting region 120. In some embodiments, the light diffractive region 152 covers less than 35, 30, 25, 20, 15, 10, or 5 percent of the light emitting region 110. For example, in some embodiments, in the top plan view, the light diffractive region 152 covers more than 80% of the light non-emitting region 120 and less than 20% of the light emitting region 110, or covers more than 90% of the light non-emitting region 120 and less than 10% of the light emitting region 110, or covers more than 95% of the light non-emitting region 120 and less than 5% of the light emitting region 110.

[0050] In some embodiments, the pixels and the subpixels of the first and second pluralities 110a and 110b of subpixels are arranged so that for the red subpixels, for the green subpixels, and for the blue subpixels, light emitted by the subpixels is transmitted by the light diffractive layer 150, 150', 150", 150'" and exits the display system in air toward the viewer, where at least some of the emitted light is diffractively transmitted by the light diffractive layer 150, 150', 150", 150'", such that: in a first plane (e.g., xz-plane) parallel to the thickness direction, the exiting light has a first luminance profile as a function of light propagation angle relative to the thickness direction that is substantially symmetric (e.g., symmetric, or nominally symmetric, or symmetric to within 10 or 5 percent variation) about a second plane (e.g., yz-plane) parallel to the thickness direction and orthogonal to the first plane at least for light propagation angle relative to the thickness direction in a range of about -50 degrees to about 50 degrees; and in the second plane, the exiting light has a second luminance profile as a function of light propagation angle relative to the thickness direction that is substantially symmetric about the first plane at least for light propagation angle relative to the thickness direction in a range of about -50 degrees to about 50 degrees. In some embodiments (see, e.g., FIGS. 2-4), for each pixel 105, the first and second pluralities 110a and 110b of subpixels are arranged into respective first and second rows 130a and 130b of the subpixels extending along a same in-plane first direction (e.g., x-direction) and spaced apart along an inplane second direction (e.g., y-direction) orthogonal to the first direction, where the subpixels in the first row 130a are arranged in a first sequence of red, green and blue subpixels and the subpixels in the second row 130b are arranged in a second sequence of red, green, and blue subpixels opposite to the first sequence. In some embodiments, in the top plan view and for each pixel, the light diffractive region 152 covers more than 60% (or in a range described elsewhere herein) of space between the first and second rows of subpixels and less than 40% (or in a range described elsewhere herein) of space between adjacent subpixels of each row. In some embodiments, in the top plan view, the light diffractive region 152 covers space between adjacent subpixels in each row 130a, 130b, but does not cover regions between adjacent subpixels of the same color in different rows 130a, 130b (see, e.g., FIG. 5). In some embodiments, the light diffractive region 152 includes a plurality of substantially parallel linear diffractive elements extending along the in-plane first direction and arranged along the in-plane second direction. In some embodiments, the light diffractive region 152 includes a two-dimensional grating comprising a plurality of diffractive elements arranged along each of the first direction and an in-plane second direction orthogonal to the first direction.

[0051] In some embodiments, for each pixel 105, the first and second pluralities 110a and 110b of subpixels are arranged into respective first and second rows 130a and 130b of the subpixels extending along a same in-plane first direction (e.g., y-direction) and spaced apart along an in-plane second direction (e.g., x-direction) orthogonal to the first direction, where the subpixels in the first and second rows 130a and 130b form pairs of subpixels such that in the top plan view, the light diffractive region covers more than 60% (or in a range described elsewhere herein) of each space between adjacent pairs of the subpixels and less than 40% (or in a range described elsewhere herein) of space between adjacent subpixels of each pair. In some embodiments, the light diffractive region 152 includes a plurality of substantially parallel linear diffractive elements extending along the in-plane second direction and arranged along the in-plane first direction. In some embodiments, the light diffractive region 152 includes a two-dimensional grating comprising a plurality of diffractive elements arranged along each of the first direction and an in-plane second direction orthogonal to the first direction.

[0052] For any of the display systems of the present description, the light diffractive layer 150, 150', 150", 150"' can cause an on-axis luminance of light exiting the display system to increase by at least about 20%, for example. In some embodiments, for at least a same one (e.g., 1 lOgl, 110g2) of the at least three different subpixels of each of the first and second pluralities of subpixels 110a, 110b of each of the pixels 105, when light emitted by the subpixels is transmitted by the light diffractive layer 150, 150', 150", 150'" and exits the display system in air toward the viewer, the light diffractive layer 150, 150', 150", 150'" causes an on-axis (e.g., along z-axis) luminance of the exiting light to increase by at least about 20, 25, 30, 35, or 40 percent. The increase can be up to about 100, 90, or 80 percent, for example. The increase is relative to the display system without the light diffractive layer 150, 150', 150", 150"'. For example, the light diffractive layer 150, 150', 150", 150'" causing an on-axis luminance of the exiting light to increase by at least 20% means that the on-axis luminance is at least 1.2 times a corresponding on-axis luminance of a comparative display system 100C having a same construction as the display system except that the comparative display system 100C does not include the light diffractive layer 150, 150', 150", 150'". In other words, the normalized luminance relative to the comparative display system at a light propagation angle of 0 degrees can be at least 1.2.

[0053] For any of the display systems of the present description, the light diffractive layer 150, 150', 150", 150'" can cause a luminance of light exiting the display system to have a full width at a specified fraction of a maximum luminance in a plane to be substantially greater for one plane than an orthogonal plane. The specified fraction can be 14, 2 / 3, or %, for example. The full width at the specified fraction is the narrowest width (in the case of multiple peaks, for example) of an angular range containing the maximum and ending at a luminance having the specified fraction of the maximum. For example, in FIG. 10B, the full width at % maximum is about 23 degrees for Example 2 in the vertical plane (since the maximum occurs at about 0 degrees and the % maximum occurs at about ± 11.5 degrees) and roughly 65 degrees for each peak for Control 2 (since % maximum of the peak at about 65 degrees occurs at approximately 10 and 75 degrees). As another example, in FIG. 10A. the full width at % maximum for Example 2 in the horizontal plane is approximately 90 degrees (since the maximum occurs at about 0 degrees and the % maximum occurs at about ± 45 degrees). As still another example, in FIG. 10B, the full width at 2 / 3 maximum is roughly 150 degrees for Control 2 since the narrowest range including either of the maxima where the luminance has dropped to 2 / 3 maximum is from roughly -75 degrees to +75 degrees.

[0054] In some embodiments, for at least a same one (e.g., 1 lOgl, 110g2) of the at least three different subpixels of each of the first and second pluralities of subpixels 110a, 110b of each of the pixels 105, when light emitted by the subpixels is transmitted by the light diffractive layer 150, 150', 150", 150'" and exits the display system in air toward the viewer 109, the exiting light has a luminance as function of light propagation angle relative to the thickness direction (z -direction) that has a full width at % maximum, or at 2 / 3 maximum, of less than about 50 degrees in a first plane (e.g., yz-plane) and greater than about 60 degrees in a second plane (e.g., xz-plane). The first and second planes can be orthogonal to one another and parallel to the thickness direction. The full width at % maximum, or at 2 / 3 maximum, can be less than about 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, or 35 degrees in the first plane. The full width at % maximum, or at 2 / 3 maximum, can be greater than about 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, or 140 degrees in the second plane.

[0055] In some embodiments, for a pair of subpixels including one subpixel of each of the first and second pluralities of subpixels where each subpixel of the pair has a substantially same emission spectrum, when light emitted by the pair of subpixels is transmitted by the light diffractive layer 150, 150', 150", 150"' and exits the display system in air toward the viewer 109, the exiting light has a luminance as function of light propagation angle relative to the thickness direction that has a full width at % maximum, or 2 / 3 maximum, of less than about 50 degrees (or another range described elsewhere herein) in the first plane and greater than about 70 degrees (or in another range described elsewhere herein) in the second plane.

[0056] In some embodiments, for a pair of subpixels including one subpixel of each of the first and second pluralities 110a and 110b of subpixels where each subpixel of the pair has a substantially same emission spectrum, when light emitted by the pair of subpixels is transmitted by the light diffractive layer 150, 150', 150", 150'" and exits the display system in air toward the viewer 109, the exiting light has a normalized luminance as function of light propagation angle relative to the thickness direction that is greater than 1.4, 1.42, 1.44, 1.46, 1.48, 1.5, 1.52, 1.54, 1.56, or 1.58 and varies ([max - min] / max x 100%) by less than 20% throughout a range of the light propagation angle of about -20 degrees to about 20 degrees. The range of the light propagation angle can extend down to about -22, -24, -26, -28, -30, - 32, -34, -36, -38, -40) degrees. The range of the light propagation angle can extend up to about 22, 24, 26, 28, 30, 32, 34, 36, 38, 40) degrees. For example, the range of the light propagation angle can be about -24 degrees to 24 degrees, or -30 degrees to 30 degrees, or -36 degrees to 36 degrees, or -40 degrees to 40 degrees. The variation can be less than 18, 16, 14, 12, or 10 percent throughout the range. For example, in FIG. 9, the normalized luminance for Example 1 has a maximum variation of about (1.6-1 ,45) / l .6 x 100%, or about 9%, over the range from about -40 degrees to about 40 degrees. Here, the normalized luminance is the luminance of the display system when light is emitted by the pair of subpixels divided by the luminance of a comparative display system 100C having a same construction as the display system except not including the light diffractive layer when light is emitted by a corresponding pair of subpixels of the comparative display system.

[0057] In some embodiments, for each pixel and for a first subpixel of the first plurality of pixels 110a and a second subpixel of the second plurality of subpixels 110b where the first and second subpixels have a substantially same emission spectrum, when the first subpixel, but not the second subpixel, emits light, light emitted by the first subpixel is transmitted by the light diffractive layer 150, 150', 150", 150'" and exits the display system in air toward the viewer as a first exiting light, such that for at least one of the first and second planes, the first exiting light has a luminance profile as a function of light propagation angle relative to the thickness direction in a range of about -50 degrees to about 50 degrees that is substantially asymmetric about the plane. For example, in the embodiments of FIGS. 2-4, the distribution will be asymmetric about the yz-plane for a red subpixel 1 lOrl, 110r2 and for a blue subpixel 110b 1 , 110b2, but not for a green (center) subpixel 1 lOgl, 110g2. As another example, in the embodiment of FIG. 5, the distribution will be asymmetric about the yz-plane for each of one red subpixel 1 lOrl or 110r2; one blue subpixel HObl or 110b2; and one green (center) subpixel HOgl or 110g2. Terms such as “about” will be understood in the context in which they are used and described in the present description by one of ordinary skill in the art. If the use of “about” as applied to quantities expressing feature sizes, amounts, and physical properties is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, “about” will be understood to mean within 10 percent of the specified value. A quantity given as about a specified value can be precisely the specified value. For example, if it is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, a quantity having a value of about 1, means that the quantity has a value between 0.9 and 1. 1, and that the value could be 1.

[0058] Terms such as “substantially” will be understood in the context in which they are used and described in the present description by one of ordinary skill in the art. If the use of “substantially” with reference to a property or characteristic is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description and when it would be clear to one of ordinary skill in the art what is meant by an opposite of that property or characteristic, the term “substantially” will be understood to mean that the property or characteristic is exhibited to a greater extent than the opposite of that property or characteristic is exhibited.

[0059] All references, patents, and patent applications referenced in the foregoing are hereby incorporated herein by reference in their entirety in a consistent manner. In the event of inconsistencies or contradictions between portions of the incorporated references and this application, the information in the preceding description shall control.

[0060] Descriptions for elements in figures should be understood to apply equally to corresponding elements in other figures, unless indicated otherwise. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and / or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations, or variations, or combinations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.

Claims

What is claimed is:

1. A display system comprising: a display region comprising a plurality of pixels configured to form an image thereacross for viewing by a viewer, each pixel comprising nonoverlapping first and second pluralities of subpixels, each of the first and second pluralities comprising at least three different subpixels having at least three different emission spectra, the subpixels defining non-overlapping first and second intra-pixel regions therebetween for each pixel, the pixels defining an inter-pixel region therebetween, each of the first and second intra-pixel regions and the inter-pixel region devoid of any light emitting subpixel, the subpixels and the first intra-pixel region defining a first combined region, the second intra-pixel regions and the inter-pixel regions defining a second combined region; and a light diffractive layer configured to be between the viewer and the display region and disposed substantially parallel to, and spaced apart along a thickness direction of the display system from, the display region, the light diffractive layer comprising a light diffractive region configured to diffract light and a light non-diffractive region not configured to diffract light, the light non-diffractive and diffractive regions of the light diffractive layer aligned, and substantially coextensive in length and width, with the respective first and second combined regions, such that for each pixel, for a first light emission angle relative to the thickness direction of greater than about 10 degrees and a second light emission angle relative to the thickness direction of less than about -10 degrees, and for first and second planes orthogonal to one another and parallel to the thickness direction: for a first subpixel of the first plurality of subpixels, light emitted by the first subpixel in the first plane at the first emission angle is diffractively transmitted by the light diffractive region of the light diffractive layer, and light emitted by the first subpixel in the first plane at the second emission angle is non-diffractively transmitted by the light non-diffractive region of the light diffractive layer; for a second subpixel of the second plurality of subpixels, the first and second subpixels having a substantially same first emission spectrum, light emitted by the second subpixel in the first plane at the second emission angle is diffractively transmitted by the light diffractive region of the light diffractive layer, and light emitted by the second subpixel in the first plane at the first emission angle is non- diffractively transmitted by the light non-diffractive region of the light diffractive layer; and for each subpixel of each of the first and second pluralities of subpixels, light emitted by the subpixel in the second plane at the each of the first and second emission angles is diffractively transmitted by the light diffractive region of the light diffractive layer.

2. The display system of claim 1, wherein for a third subpixel in the first plurality of subpixels and a fourth subpixel in the second plurality of subpixels, the third and fourth subpixels having a substantially same second emission spectrum substantially different from the first emission spectrum:light emitted by the third subpixel in the first plane at the second emission angle is diffractively transmitted by the light diffractive region of the light diffractive layer, and light emitted by the third subpixel in the first plane at the first emission angle is non-diffractively transmitted by the light non- diffractive region of the light diffractive layer; and light emitted by the fourth subpixel in the first plane at the first emission angle is diffractively transmitted by the light diffractive region of the light diffractive layer, and light emitted by the fourth subpixel in the first plane at the second emission angle is non-diffractively transmitted by the light non- diffractive region of the light diffractive layer.

3. The display system of claim 2, wherein for a fifth subpixel in the first plurality of subpixels and a sixth subpixel in the second plurality of subpixels, the fifth and sixth subpixels having a substantially same third emission spectrum substantially different from each of the first and second emission spectra: light emitted by the fifth subpixel in the first plane at the second emission angle is diffractively transmitted by the light diffractive region of the light diffractive layer, and light emitted by the fifth subpixel in the first plane at the first emission angle is non-diffractively transmitted by the light non- diffractive region of the light diffractive layer; and light emitted by the sixth subpixel in the first plane at the first emission angle is diffractively transmitted by the light diffractive region of the light diffractive layer, and light emitted by the sixth subpixel in the first plane at the second emission angle is non-diffractively transmitted by the light non- diffractive region of the light diffractive layer.

4. The display system of claim 2, wherein for each of a fifth subpixel in the first plurality of subpixels and a sixth subpixel in the second plurality of subpixels, the fifth and sixth subpixels having a substantially same third emission spectrum substantially different from each of the first and second emission spectra, and for each of the first and second emission angles, light emitted by the subpixel in the first plane is non-diffractively transmitted by the light non-diffractive region of the light diffractive layer.

5. The display system of claim 1, wherein for a pair of subpixels comprising one subpixel of each of the first and second pluralities of subpixels, each subpixel of the pair having a substantially same emission spectrum, when light emitted by the pair of subpixels is transmitted by the light diffractive layer and exits the display system in air toward the viewer, the exiting light has a luminance as function of light propagation angle relative to the thickness direction that has a full width at % maximum of less than about 50 degrees in the first plane and greater than about 60 degrees in the second plane.

6. The display system of claim 1, wherein for a pair of subpixels comprising one subpixel of each of the first and second pluralities of subpixels, each subpixel of the pair having a substantially same emission spectrum, when light emitted by the pair of subpixels is transmitted by the light diffractive layer and exitsthe display system in air toward the viewer, the exiting light has a normalized luminance as function of light propagation angle relative to the thickness direction that is greater than 1.5 and varies by less than 20% throughout a range of the light propagation angle of about -20 degrees to about 20 degrees, the normalized luminance being the luminance of the display system when light is emitted by the pair of subpixels divided by the luminance of a comparative display system having a same construction as the display system except not including the light diffractive layer when light is emitted by a corresponding pair of subpixels of the comparative display system.

7. The display system of claim 1, wherein for each pixel, the first and second pluralities of subpixels are arranged into respective first and second rows of the subpixels extending along a same in-plane first direction and spaced apart along an in-plane second direction orthogonal to the first direction, the subpixels in the first row arranged in a first sequence of red, green and blue subpixels and the subpixels in the second row arranged in a second sequence of red, green, and blue subpixels opposite to the first sequence.

8. The display system of claim 1, wherein for each pixel, the first and second pluralities of subpixels are arranged into respective first and second rows of the subpixels extending along a same in-plane first direction and spaced apart along an in-plane second direction orthogonal to the first direction, the subpixels of each of the first and second rows arranged in a same sequence of red, green, and blue subpixels, the subpixels in the first and second rows forming pairs of adjacent subpixels such that for each pair, the subpixels of the pair have a substantially same emission spectrum.

9. A display system comprising: a display region configured to form an image thereacross for viewing by a viewer and comprising a plurality of pixels defining a light emitting region configured to emit light and a light non-emitting region not configured to emit light, each pixel comprising nonoverlapping first and second pluralities of subpixels, each of the first and second pluralities of subpixels comprising red, green and blue subpixels; and a light diffractive layer comprising a light diffractive region configured to diffract light and a light non-diffractive region not configured to diffract light, the light diffractive layer disposed on, and spaced apart along a thickness direction of the display system from, the display region, such that in a top plan view, the light diffractive region covers more than 60% of the light non-emitting region and less than 40% of the light emitting region, wherein the pixels and the subpixels of the first and second pluralities of subpixels are arranged so that for the red subpixels, for the green subpixels, and for the blue subpixels, light emitted by the subpixels is transmitted by the light diffractive layer and exits the display system in air toward theviewer, at least some of the emitted light being diffractively transmitted by the light diffractive layer, such that: in a first plane parallel to the thickness direction, the exiting light has a first luminance profile as a function of light propagation angle relative to the thickness direction that is substantially symmetric about a second plane parallel to the thickness direction and orthogonal to the first plane at least for light propagation angle relative to the thickness direction in a range of about -50 degrees to about 50 degrees; and in the second plane, the exiting light has a second luminance profile as a function of light propagation angle relative to the thickness direction that is substantially symmetric about the first plane at least for light propagation angle relative to the thickness direction in a range of about -50 degrees to about 50 degrees.

10. The display system of claim 9, wherein for each pixel, the first and second pluralities of subpixels are arranged into respective first and second rows of the subpixels extending along a same in-plane first direction and spaced apart along an in-plane second direction orthogonal to the first direction, the subpixels in the first row arranged in a first sequence of red, green and blue subpixels and the subpixels in the second row are arranged in a second sequence of red, green, and blue subpixels opposite to the first sequence.

11. The display system of claim 9, wherein the light diffractive region comprises a plurality of substantially parallel linear diffractive elements extending along the in-plane first direction and arranged along the in-plane second direction.

12. The display system of claim 9, wherein the light diffractive region comprises a two-dimensional grating comprising a plurality of diffractive elements arranged along each of the first direction and an inplane second direction orthogonal to the first direction.

13. The display system of claim 9, wherein for each pixel, the first and second pluralities of subpixels are arranged into respective first and second rows of the subpixels extending along a same in-plane first direction and spaced apart along an in-plane second direction orthogonal to the first direction, the subpixels in the first and second rows forming pairs of subpixels such that in the top plan view, the light diffractive region covers more than 60% of each space between adjacent pairs of the subpixels and less than 40% of space between adjacent subpixels of each pair.

14. The display system of claim 13, wherein the light diffractive region comprises a plurality of substantially parallel linear diffractive elements extending along the in-plane second direction and arranged along the in-plane first direction.

15. The display system of claim 9, wherein for each pixel and for a first subpixel of the first plurality of pixels and a second subpixel of the second plurality of subpixels, the first and second subpixels having a substantially same emission spectrum, when the first subpixel, but not the second subpixel, emits light, light emitted by the first subpixel is transmitted by the light diffractive layer and exits the display system in air toward the viewer as a first exiting light, such that for at least one of the first and second planes, the first exiting light has a luminance profile as a function of light propagation angle relative to the thickness direction in a range of about -50 degrees to about 50 degrees that is substantially asymmetric about the plane.

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