Display system comprising a layer having diffractive and non-diffractive regions

Abstract

A display system includes a display area including a plurality of pixels configured to form an image across the display area for viewing by a viewer; and a light-diffraction layer configured to be interposed between the viewer and the display area. Each pixel can include a first plurality of sub-pixels and a second plurality of sub-pixels. Sub-pixels define intra-pixel areas therebetween, and inter-pixel areas therebetween. The diffraction layer includes light-diffraction areas configured to diffract light and non-light-diffraction areas not configured to diffract light. The non-diffraction areas substantially overlap with sub-pixels and portions of intra-pixel and inter-pixel areas. The diffraction areas substantially overlap with intra-pixel and inter-pixel areas not overlapped by the non-light-diffraction areas. The portions of intra-pixel and inter-pixel areas can be selected to provide a desired brightness profile of light emitted by the pixels and transmitted by the diffraction layer.

Description

Technical Field

[0001] This manual pertains to the display system in its entirety. Background Technology

[0002] The display system may include a miniature light-emitting diode (micro-LED) display panel. Summary of the Invention

[0003] In some aspects, this specification provides a display system including a display area comprising a plurality of pixels configured to form an image across the display area for viewing by a viewer; and a light diffraction layer configured between the viewer and the display area. Each pixel may include a first plurality of subpixels and a second plurality of subpixels. Intra-pixel regions are defined between subpixels, and inter-pixel regions are defined between pixels. The diffraction layer includes a light diffraction region configured to diffract light and a non-light diffraction region not configured to diffract light. The non-diffraction region substantially overlaps with portions of the subpixels and the intra-pixel and inter-pixel regions. The diffraction region substantially overlaps with the intra-pixel and inter-pixel regions not overlapped by the non-light diffraction region. These portions of the intra-pixel and inter-pixel regions can be selected to provide a desired brightness distribution of light emitted by the pixels and transmitted by the diffraction layer.

[0004] In some aspects, this specification provides a display system including a display area comprising a plurality of pixels configured to form an image across the display area for viewing by a viewer; and a light diffraction layer configured between the viewer and the display area, and disposed substantially parallel to the display area and spaced apart from the display area along the thickness direction of the display system. Each pixel may include three or more sub-pixels. For each pixel, non-overlapping first intra-pixel regions and second intra-pixel regions are defined between the sub-pixels. Non-overlapping first inter-pixel regions and second inter-pixel regions are defined between the pixels. Each of the first intra-pixel regions and second intra-pixel regions, as well as the first inter-pixel regions and second inter-pixel regions, contains no light-emitting sub-pixels. The sub-pixels, the first intra-pixel regions, and the first inter-pixel regions define a first combined region, and the second intra-pixel regions and the second inter-pixel regions define a second combined region. The light diffraction layer includes a light diffraction region configured to diffract light and a non-light diffraction region not configured to diffract light. The non-diffraction and diffraction regions of the optical diffraction layer are aligned with the corresponding first and second combined regions and extend substantially together with them in length and width, such that for each sub-pixel, for a first emission angle greater than about 10 degrees relative to the thickness direction and a second emission angle less than about -10 degrees relative to the thickness direction, and for a first and second plane orthogonal to each other and parallel to the thickness direction: light emitted by the sub-pixel in the first plane at each of the first and second emission angles is diffractically transmitted by the optical diffraction region of the optical diffraction layer; and light emitted by the sub-pixel in the second plane at each of the first and second emission angles is non-diffraction transmitted through the non-diffraction region of the optical diffraction layer.

[0005] In some aspects, this specification provides a display system comprising: a display area configured to form an image across the display area for viewing by a viewer, and including a plurality of pixels defining a light-emitting region configured to emit light and a non-light-emitting region not configured to emit light; and a light diffraction layer configured between the viewer and the display area, and disposed substantially parallel to the display area and spaced apart from the display area along the thickness direction of the display system. Each pixel includes a first plurality of non-overlapping sub-pixels and a second plurality of sub-pixels, wherein each of the first plurality of sub-pixels and the second plurality of sub-pixels includes at least three different sub-pixels having at least three different emission spectra. The light diffraction layer includes a light diffraction region configured to diffract light and a non-light diffraction region not configured to diffract light. The light diffraction region is aligned with and extends substantially co-located with the first non-light-emitting region of the non-light-emitting region in length and width. The non-light diffraction region is aligned with and extends substantially co-located with the second non-light-emitting region, which includes both the light-emitting and non-light-emitting regions. The first non-emissive region and the second non-emissive region are non-overlapping regions selected from the non-emissive region, such that for each of the first plurality of sub-pixels and the combined plurality of sub-pixels including the first plurality of sub-pixels and the second plurality of sub-pixels, light emitted by the sub-pixels is transmitted through the light diffraction layer and exits the display system toward the viewer in air, wherein at least some of the emitted light is diffracted through the light diffraction layer, such that: in a first plane parallel to the thickness direction, at least for light propagation angles in the range of about -50 degrees to about 50 degrees, the emitted light has a substantially identical first normalized brightness distribution as a function of the light propagation angle relative to the thickness direction; and in a second plane parallel to the thickness direction and orthogonal to the first plane, at least for light propagation angles in the range of about -50 degrees to about 50 degrees, the emitted light has a substantially identical second normalized brightness distribution as a function of the light propagation angle relative to the thickness direction.

[0006] In some aspects, this specification provides a display system comprising: a display area configured to form an image across the display area for viewing by a viewer, and including a plurality of pixels defining a light-emitting region configured to emit light and a non-light-emitting region not configured to emit light; and a light diffraction layer configured between the viewer and the display area, and disposed substantially parallel to the display area and spaced apart from the display area along the thickness direction of the display system. Each pixel includes a first plurality of non-overlapping sub-pixels and a second plurality of sub-pixels, wherein each of the first plurality of sub-pixels and the second plurality of sub-pixels includes at least three different sub-pixels having at least three different emission spectra. The light diffraction layer includes a light diffraction region configured to diffract light and a non-light diffraction region not configured to diffract light. The light diffraction region is aligned with and extends substantially co-located with the first non-light-emitting region of the non-light-emitting region in length and width. The non-light diffraction region is aligned with and extends substantially co-located with the second non-light-emitting region, which includes both the light-emitting and non-light-emitting regions. The first non-emissive region and the second non-emissive region are non-overlapping regions selected from the non-emissive region, such that for each of the first plurality of sub-pixels and the combined plurality of sub-pixels including the first plurality of sub-pixels and the second plurality of sub-pixels, light emitted by the sub-pixel is transmitted through the light diffraction layer and exits the display system toward the viewer in air, wherein at least some of the emitted light is diffracted through the light diffraction layer, such that: in a first plane parallel to the thickness direction, at least for light propagation angles in the range of about -50 degrees to about 50 degrees relative to the thickness direction, the emitted light has a first brightness distribution as a function of the light propagation angle relative to the thickness direction, the first brightness distribution being substantially symmetrical about a second plane parallel to the thickness direction and orthogonal to the first plane; and in the second plane, at least for light propagation angles in the range of about -50 degrees to about 50 degrees relative to the thickness direction, the emitted light has a second brightness distribution as a function of the light propagation angle relative to the thickness direction, the second brightness distribution being substantially symmetrical about the first plane.

[0007] These and other aspects will become apparent from the detailed description that follows. However, in no way should this brief overview be construed as limiting the subject matter for which protection may be claimed. Attached Figure Description

[0008] Figures 1A to 1B It is a schematic cross-sectional view of a part of a display system according to some implementation schemes.

[0009] Figures 2 to 4 This is a schematic top plan view of a portion of the display system according to some implementation schemes.

[0010] Figure 5 It is a schematic top plan view of pixels according to some implementation schemes.

[0011] Figure 6 It is a schematic graph of the emission spectrum of a subpixel according to some implementation schemes.

[0012] Figures 7A to 7D A luminance distribution graph is shown for a display system including a diffraction layer with linear diffraction elements according to some embodiments.

[0013] Figure 8 A brightness distribution graph of a display system including a diffraction layer with a two-dimensional grating, according to some embodiments, is shown. Detailed Implementation

[0014] Reference is made in the following description to the accompanying drawings, which form part of this disclosure and in which various embodiments are illustrated by way of example. The drawings are not necessarily drawn to scale. It should be understood that other embodiments may be conceived and practiced without departing from the scope or spirit of this specification. Therefore, the following detailed description should not be considered limiting.

[0015] The display system emits light in an axial direction toward the viewer and in an off-axis direction. In some cases, it is desired that at least some of the off-axis light be redirected substantially along the axial direction in at least one plane (e.g., in a vertical plane) to increase the axial luminance and apparent luminance experienced by the viewer. Typically, the light output with the desired increase in axial apparent luminance has a desired (e.g., symmetrical) luminance distribution as a function of the light propagation angle. According to some embodiments, a suitably patterned light diffraction layer as described herein has been found to be used to achieve improved axial apparent luminance with the desired luminance distribution. The suitably patterned light diffraction layer may include non-diffractive regions that cover the luminescent regions of the display and portions of the non-luminescent regions selected to produce the desired luminance distribution. Luminance can be measured using standard photometric techniques, where the CIE 1931 tri-color stimulus is used. The function can be used as a photoluminescence efficiency function to convert radiation into luminescence.

[0016] Diffraction gratings have been used in conjunction with displays for other purposes. Diffraction gratings can be placed above organic light-emitting diode (OLED) display panels to correct off-axis color shift, as described, for example, in U.S. Patent No. 10,991,765 (Freier et al.). Diffraction structures can be positioned on the emitting region of the OLED device, within the evanescent region of the emitting region, to improve light extraction where light would otherwise be trapped in the OLED device in other ways, as described, for example, in U.S. Patent Application Publication No. 2010 / 0110551 (Lamansky et al.). In each of these cases, the diffraction layer is placed above the entire emitting layer of the OLED device. However, when a diffraction grating is placed above the entire emitting layer and selected to provide at least some of the off-axis light to first-order diffraction in the axial direction, some light emitted axially by the pixels will be diffracted to the off-axis direction, thus substantially not increasing the axial apparent brightness by redirecting the off-axis light. Diffraction gratings have also been used in the non-light-emitting areas of displays to increase the axial efficiency of the display, as described in International Application Publication No. WO 2024 / 033838 (DeSutter et al.).

[0017] According to some embodiments of this specification, the light diffraction layer can be patterned to include a light diffraction region above a portion of a non-emitting area of ​​the display surface, but not above an emitting area (e.g., a sub-pixel), and this allows at least some of the off-axis light to be diffracted to (or near) the axial direction, while substantially not diffracting the emitted axial light to the non-axial direction. It has been found that the portion of the non-emitting area covered by the light diffraction region can be selected to give desired characteristics of the brightness distribution of light leaving the display. In some embodiments, this can result in a significant increase in axial brightness (e.g., at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or even 50%) compared to a comparison display system without a diffraction layer and / or compared to a display system including a diffraction layer with a diffraction structure covering the entire display panel.

[0018] A display may include pixels, each of which includes at least two sets of subpixels for redundancy. For example, a micro-light-emitting diode (micro-LED) display panel may include such redundant subpixels because it is difficult to reliably provide defect-free micro-LEDs. However, it has been found that when redundant subpixels are included, placing a light diffraction layer above the display surface (where the non-diffraction region is above the subpixels and the diffraction region is above the inter-pixel region between the pixels) can result in undesirable characteristics of the brightness distribution of the emitted light. For example, as further described elsewhere herein, it has been found that light from a first set of subpixels (e.g., the primary subpixel) may have a different normalized brightness distribution after transmission through the light diffraction layer than light from a second set of subpixels (e.g., secondary subpixels or redundant subpixels) or light from a combination of the first and second sets. This is because light from a subpixel is diffractedly transmitted by the light diffraction layer when emitted in a first plane at a first emission angle (e.g., greater than 10 degrees with respect to the normal), but is non-diffractively transmitted when emitted at the opposite second emission angle (e.g., less than -10 degrees with respect to the normal). Additionally or alternatively, it has been found that this may result in undesirable asymmetry between the brightness of the transmitted light emitted at the first emission angle and the second emission angle. However, according to some embodiments of this specification, it has been found that the area of ​​the display covered by the diffraction region (e.g., covering some intra-pixel regions and some intra-pixel regions) can be selected such that the resulting normalized brightness distribution has desired symmetry (e.g., symmetry about reflections of one or more planes and / or symmetry between the first sub-pixel and the second sub-pixel or between the first sub-pixel and a combination of the first and second sub-pixels).

[0019] Brightness distribution can be normalized by any fixed value. For example, normalized brightness distribution can be the brightness distribution divided by the value of the brightness distribution at 0 degrees relative to the normal or thickness direction of the display, or normalized brightness distribution can be the brightness distribution divided by the value of the comparative brightness distribution at 0 degrees relative to the normal or thickness direction of the display, where the comparative brightness distribution is the brightness distribution of a comparative display system that has the same structure as the display system except that it does not include a light diffraction layer.

[0020] A pixel is the smallest addressable element that forms an image unit in a display, where the unit can produce the display's color gamut. For example, a standard full (1080p) high-definition display includes 1920 × 1080 pixels, and a standard 4K display includes 3840 × 2160 pixels. A pixel typically comprises at least three subpixels, allowing the pixel to produce the desired color gamut. When redundant subpixels are included, a pixel typically comprises at least six subpixels (e.g., red, green, and blue subpixels of a first (primary) plurality of subpixels and red, green, and blue subpixels of a second (redundant) plurality of subpixels). The area between the subpixels of a pixel is referred to as the intra-pixel region, and the area between pixels is referred to as the inter-pixel region.

[0021] Figures 1A to 1B This is a schematic cross-sectional view of a display system 100 according to some implementation schemes. Figures 2 to 4 This is a schematic top plan view of a portion of display systems 100, 100', 100'' according to some embodiments. Display systems 100, 100', 100'' include a display area 101 comprising a light-emitting area 110 (e.g., a subpixel) and a non-light-emitting area 120 (e.g., an inter-pixel non-light-emitting area or an intra-pixel non-light-emitting area). The display system may include (e.g., emit) a display layer 151 including the display area 101. Display systems 100, 100', 100'' include light diffraction layers 150, 150', 150''. Light diffraction layer 150 includes a linear grating in display system 100, and light diffraction layers 150', 150'' include a two-dimensional grating in display systems 100', 100''. Display system 100'' has a pixel layout different from display systems 100 and 100'. The pixel layout of the display system 100'' can optionally be used with a linear grating, such as the linear grating of the light diffraction layer 150.

[0022] In some embodiments, display systems 100, 100', 100'' include a display area 101 comprising a plurality of pixels 105 configured to form an image 107 across the display area for viewing by a viewer 109. Each pixel may include three or more subpixels. In some embodiments, each pixel may include a first plurality of non-overlapping subpixels 110a and a second plurality of non-overlapping subpixels 110b. Each of the first plurality of 110a and the second plurality of 110b may include at least three distinct subpixels having at least three different emission spectra (see, for example...). Figures 5 to 6For each pixel, sub-pixels 110 define non-overlapping first intra-pixel regions 111 and 112. Pixels define non-overlapping first inter-pixel regions 121 and 122. Neither the first intra-pixel regions and the second intra-pixel regions, nor the first inter-pixel regions and the second inter-pixel regions, contain any luminous sub-pixels. Intra-pixel regions are typically regions within a pixel, while inter-pixel regions are located between adjacent pixels. Each sub-pixel typically defines a luminous region, and since the first intra-pixel regions and the second intra-pixel regions are defined as being located between sub-pixels, they are non-luminous regions. Similarly, since the first inter-pixel regions and the second inter-pixel regions are defined as being located between pixels, they are also non-luminous regions. In the illustrated embodiment, the first intra-pixel region 111 is located between adjacent sub-pixels arranged along the same row (along the x-direction) of the pixel, the second intra-pixel region 112 is located between adjacent rows of sub-pixels of the pixel, the first inter-pixel region 121 is located between adjacent rows of sub-pixels of adjacent pixels, and the second inter-pixel region 122 can be substantially all inter-pixel regions except for the first inter-pixel region 121. Sub-pixels 110, the first intra-pixel region 111, and the first inter-pixel region 121 define a first combined region (i.e., the first combined region is a combination of sub-pixels, the first intra-pixel region 111, and the first inter-pixel region 121), and the second intra-pixel region 112 and the second inter-pixel region 122 define a second combined region (i.e., the second combined region is a combination of the second intra-pixel region 112 and the second inter-pixel region 122).

[0023] Display systems 100, 100', 100'' include light diffraction layers 150, 150', 150'' configured to be interposed between a viewer 109 and a display area 101, arranged substantially parallel to the display area 101 (e.g., within 20 degrees, 15 degrees, 10 degrees, or 5 degrees of being parallel or nominally parallel to the display area), and spaced apart from the display area along the thickness direction (z-direction) of the display system 100 (or the thickness direction of the light diffraction layer). The light diffraction layers 150, 150', 150'' include light diffraction regions 152 configured to diffract light and non-light-diffraction regions 154 not configured to diffract light. The non-light-diffraction regions and light diffraction regions of the light diffraction layers 150, 150', 150'' may be aligned with respective first combined regions and second combined regions, and extend substantially coextensively therewith in length and width, such that for each subpixel, for a first light emission angle a1 greater than about 10 degrees (or greater than about 15 or 20 degrees) relative to the thickness direction and a second light emission angle a2 less than about -10 degrees (or less than about -15 degrees or -20 degrees) relative to the thickness direction, and for a first plane and a second plane (yz plane and xz plane) that are orthogonal to each other and parallel to the thickness direction (z-direction): light 141, 142 emitted by the subpixel at each of the first emission angle a1 and the second emission angle a2 in the first plane (yz plane) is diffractively transmitted by the light diffraction regions 152 of the light diffraction layers 150, 150', 150'' (as corresponding transmitted light 141' and 142' at respective light propagation angles a1' and a2' in air); and light 143, 144 emitted by the subpixel at each of the first emission angle a1 and the second emission angle a2 in the second plane (xz plane) is non-diffractively transmitted through the non-light-diffraction regions 154 of the light diffraction layers 150, 150', 150'' (as corresponding transmitted light 143' and 144'). In some embodiments, light 140 emitted along the axial direction (z-direction) is non-diffractively transmitted through the non-light-diffraction regions 154 (e.g., as transmitted light 140'). When the direction of light in the xz plane or yz plane projected onto the xy plane is along the +x axis or +y direction respectively, the light emission angle and light propagation angle in air may be defined as positive, and when the projection is along the -x direction or -y direction respectively, the light emission angle and light propagation angle in air may be defined as negative. In some embodiments, the first light emission angle a1 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 a1 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 > a1 > 10 degrees and -40 degrees < a2 < -10 degrees. In some embodiments, a2 is approximately -a1.

[0024] A layer or element can be described as substantially co-extending with each other in length and width if more than 50% of its length and width extends together with more than 50% of the length and width of each other layer or element. In some embodiments, for layers or elements described as substantially co-extending 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 extends together 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.

[0025] 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 the total area of ​​the light-diffusing region of the light-diffusing layer overlaps with 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 the total area of ​​the non-light-emitting region of the display region. For example, in some embodiments, at least 50% of the total area of ​​the light-diffusing region of the light-diffusing layer overlaps with at least 50% of the total area of ​​the non-light-emitting region of the display region, or at least 75% of the total area of ​​the light-diffusing region of the light-diffusing layer overlaps with at least 75% of the total area of ​​the non-light-emitting region of the display region, or at least 90% of the total area of ​​the light-diffusing region of the light-diffusing layer overlaps with at least 80% of the total area of ​​the non-light-emitting region of the display region. 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 the total area of ​​the non-diffraction region of the light-emitting region of the display region overlaps with 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 the total area of ​​the light-emitting region of the display region. For example, in some embodiments, at least 50% of the total area of ​​the non-diffraction region of the light-emitting region of the light-emitting region overlaps with at least 50% of the total area of ​​the light-emitting region of the display region, or at least 75% of the total area of ​​the non-diffraction region of the light-emitting ...

[0026] In some embodiments, the average spacing S1 between the light diffraction layers 150, 150', 150'' and the display area 101 is greater than about 10 micrometers, or 15 micrometers, or 20 micrometers, or 30 micrometers, or 40 micrometers, or 50 micrometers, or 100 micrometers, or 150 micrometers, or 200 micrometers, or 250 micrometers, or 300 micrometers, or 350 micrometers, or 400 micrometers, or 400 micrometers, or 500 micrometers, and less than about 5000 micrometers. In some embodiments, the average spacing is less than about 4500 micrometers, or 4000 micrometers, or 3500 micrometers, or 3000 micrometers, or 2500 micrometers, or 2000 micrometers, or 1500 micrometers, or 1000 micrometers, or 500 micrometers, or 200 micrometers, or 150 micrometers. In some embodiments, for example, the average spacing S1 is in the range of about 10 micrometers to about 5000 micrometers, or about 20 micrometers to about 4000 micrometers, or about 30 micrometers to about 2000 micrometers, or about 35 micrometers to about 200 micrometers, or about 40 micrometers to about 150 micrometers. For example, the spacing S1 can be provided by including a layer between the light diffraction layers 150, 150', 150'' and the display area 101, wherein the layer can be an encapsulant layer (e.g., a thin film) and / or an adhesive layer (e.g., an optically transparent layer), or a glass layer or another display layer, such as a polarizer or touch sensor layer.

[0027] The optical diffraction layers 150, 150', and 150'' may include a first layer 150a and a second layer 150b. In some embodiments, the first layer 150a is formed on a substrate (e.g., a polymer substrate or another layer) using a casting and curing process, wherein the diffraction structure is fabricated by a tool by casting a polymerizable resin composition onto the substrate and curing the resin into contact with a structured surface of the tool. Such casting and curing methods are described, for example, in U.S. Patent Nos. 5,175,030 (Lu et al.) and 5,183,597 (Lu), and U.S. Patent Application Publication No. 2012 / 0064296 (Walker, JR. et al.). The tool can be selected to define a structured surface that defines both optically diffracting and non-optically diffracting regions, or the tool can define an optically diffracting structure across the entire structured surface of the first layer 150a, and then, in a subsequent coating step, fill portions of the optically diffracting structure with the same material used to form the first layer 150a in the casting and curing process, or with a different material having a similar refractive index (e.g., substantially closer in refractive index to the casting and curing material compared to the material of the second layer 150b), to define the non-optically diffracting regions. The second layer 150b can be a (e.g., planarized) backfill layer coated above the structured surface defined in the first layer 150a. For example, the first layer 150a and the second layer 150b typically have different refractive indices na and nb, respectively, for at least the same first wavelength in the wavelength range of 420 nm to 680 nm. In some embodiments, the difference nb-na can be, for example, at least about 0.03, 0.05, 0.07, 0.09, or 0.1 for at least the first wavelength. In some such embodiments, or in others, the difference nb-na may be, for example, at most about 2, 1.5, 1, 0.8, 0.6, 0.5, or 0.4 for at least the first wavelength. In some embodiments, the non-diffractive region includes a structured interface, and the refractive index difference across the structured interface may be less than, for example, about 0.08, 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01 for at least the first wavelength. In some embodiments, the diffractive layers 150, 150', 150'' include more than two materials or layers. For example, the diffractive layers 150, 150', 150'' may include a thin (e.g., substantially thinner than the grating height) outer coating at the grating interface, which may have a high refractive index for at least the first wavelength (e.g., a refractive index of at least about 2, such as, for example, about 2.5). In some embodiments, at the first wavelength, layer 150a has a refractive index of about 1.4 to about 1.55, and layer 150b has a refractive index of about 1.75 to about 1.85. For example, the average spacing S1 can be in the range of about 20 micrometers to 1000 micrometers, layer 150a can have a thickness of about 10 micrometers to 20 micrometers, and layer 150b can have a thickness of about 5 micrometers to about 15 micrometers.The average spacing S1 can be in the range of about 20 micrometers to about 30 micrometers, for example in mobile phone applications, and in the range of about 30 micrometers, 35 micrometers, 40 micrometers, 45 micrometers, 50 micrometers, 60 micrometers, 70 micrometers, 80 micrometers, or 90 micrometers to about 1000 micrometers, for example in television applications. In some embodiments, the light diffraction layers 150, 150', 150'' are formed separately and then disposed on layer 151, which may be or include an emitting layer with optional air gaps therebetween, or the light diffraction layers 150, 150', 150'' may be laminated to the emitting layer.

[0028] The optically diffracting and non-optically diffracting regions can be patterned by any other suitable means. In some embodiments, the optically diffracting and non-optically diffracting regions can be patterned by inkjet printing, photolithography, masking, or other suitable patterning techniques. In some embodiments, the patterning technique determines the placement of refractive index-matched material (e.g., a refractive index difference (e.g., at 550 nm) less than about 0.08, 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01) to define the location of the non-optically diffracting region. In some embodiments, the patterning technique determines the placement of refractive index-mismatched material (e.g., a refractive index difference (e.g., at 550 nm) at least about 0.03, 0.05, 0.07, 0.09, or 0.1) to define the optically diffracting region. In some embodiments, the patterning technique defines an exposure area over which a grating is preferentially manufactured or removed, for example, by 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, wherein the etching or scribing process is patterned to define light-diffractive and non-light-diffractive regions. Other patterning methods known in the art may also be utilized.

[0029] In some embodiments, the pixels 105 are arranged into rows 130 of pixels extending along a first in-plane direction (x-direction), where each row of pixels includes a row 130a of sub-pixels 110 of a first plurality of sub-pixels 110a and a row 130b of sub-pixels 110 of a second plurality of sub-pixels 110b. The rows 130 may be spaced apart from each other along a second in-plane direction (y-direction) orthogonal to the first direction. In some embodiments, the average spacing Ws2a between the rows of sub-pixels within a row of pixels is less than the average spacing Ws2b between adjacent rows of pixels. In some embodiments, Ws2a is less than 0.9 times, 0.8 times, 0.7 times, 0.6 times, or 0.5 times of Ws2b. In some embodiments, Ws2a is greater than the average sub-pixel length along the second direction. In some embodiments, the pixels 105 have an average width Wp1 along the first direction (x-direction), and the average spacing between adjacent pixels along the first direction is Ws1. In some embodiments, Ws1>Wp1. In some embodiments, 5 (or 4, or 3, or 2) times Wp1>Ws1>Wp1. In some embodiments, Ws1<Wp1. In some embodiments, Ws1 and Wp1 are approximately equal.

[0030] In some embodiments, the light diffraction region 152 includes a plurality of substantially parallel linear diffraction elements extending along the first direction (x-direction) and arranged along the second in-plane direction (y-direction) orthogonal to the first direction (see, for example Figure 2 ). In some embodiments, the light diffraction region 152 includes a two-dimensional grating (see, for example Figures 3 to 4 ), which includes a plurality of diffraction elements arranged along each of two orthogonal in-plane directions (for example, the first direction (x-direction) and the second in-plane direction (y-direction) orthogonal to the first direction).

[0031] Figure 5This is a schematic top plan view of pixel 105 according to some embodiments. Pixel 105 includes a first plurality of sub-pixels 110a of sub-pixels 110r1, 110g1, and 110b1 (e.g., red, green, and blue sub-pixels) and a second plurality of sub-pixels 110b of sub-pixels 110r2, 110g2, and 110b2 (e.g., red, green, and blue sub-pixels). In some embodiments, adjacent sub-pixels within a pixel have an average center-to-center spacing Wc along a first direction, and an average spacing between adjacent pixels along the first direction is Ws1, where Ws1 > Wc. In some embodiments, Ws1 is at least 1.5 times, 2 times, 3 times, or 4 times Wc. Light emitted from the red (e.g., 110r1, 110r2), green (e.g., 110g1, 110g2), and blue (e.g., 110b1, 110b2) sub-pixels can include wavelengths in the visible wavelength range extending from about 400 nm to about 700 nm. For example, the emitted light from the blue sub-pixel may be blue light in the wavelength range of about 420 nm to about 490 nm, the emitted light from the green sub-pixel may be green light in the wavelength range of about 490 nm to about 590 nm, and the emitted light from the red sub-pixel may be red light in the wavelength range of about 590 nm to about 680 nm.

[0032] As is known in the art, the geometry of the 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 having a period ranging from about 0.2 micrometers to about 5 micrometers, or about 0.3 micrometers to about 3.5 micrometers, or about 0.4 micrometers to about 3 micrometers, or about 0.5 micrometers to about 2.5 micrometers, or about 0.6 micrometers to about 2 micrometers. In some embodiments, the diffractive elements form an irregular pattern having an average spacing or pitch within any range described for the period of the periodic grating. In some embodiments, the diffraction element has an average height in the range of about 0.05 micrometers to about 3.5 micrometers, or about 0.1 micrometers to about 3.25 micrometers, or about 0.2 micrometers to about 3 micrometers, or about 0.3 micrometers to about 2.75 micrometers, or about 0.4 micrometers to about 2.5 micrometers, or about 0.5 micrometers to about 2.25 micrometers, or about 0.6 micrometers to about 2 micrometers, or about 0.7 micrometers to about 1.75 micrometers, or about 0.8 micrometers to about 1.5 micrometers, or about 0.8 micrometers to about 1.25 micrometers, or about 0.8 micrometers to about 1 micrometer.

[0033] As is known in the art, when light is transmitted through a diffraction layer, the diffraction structure of the diffraction layer can be selected to diffract the light into a desired direction. The diffraction region 152 may include any suitable diffraction structure that causes light to diffract into the appropriate direction. For example, the diffraction region 152 may include a phase grating, an amplitude grating, a one-dimensional grating (e.g., comprising substantially parallel linear diffraction elements), a two-dimensional grating (e.g., on a square, rectangular, or hexagonal lattice), a subwavelength structure, a metasurface structure, and / or other diffraction structures known in the art. In some embodiments, the diffraction structure forms a grating, and the geometry and refractive index of the diffraction structure can be correlated with the desired direction, for example, by a diffraction grating equation. Exemplary diffractive structures described by the diffraction grating equation can be found, for example, in Miller et al., “Design and fabrication of binary slanted surface-relief gratings for a planar optical interconnection,” *Applied Optics*, Vol. 36, No. 23, 1997, and Moharam et al., “Formulation for stable and efficient implementation of the rigorous coupled-wave analysis of binary gratings,” *Journal of the Optical Society A*, Vol. 12, No. 5, 1995. In some embodiments, the optical diffraction structure forms a metasurface (which can be considered a diffractive surface) that provides appropriate steering in the desired direction. Exemplary metasurfaces for beam control are described, for example, in U.S. Patent Application Publication No. 2021 / 0109364 (Aieta et al.) and Jiang et al., “Free-Form Diffractive Metagrating Design Based on Generative Adversarial Networks,” ACS Nano, 13, 8872-8878, 2019. The geometry of the diffractive element can be selected in part based on the geometry of the pixel and subpixel layout and / or in part based on the desired brightness distribution along the horizontal direction (e.g., in the xz plane) and / or along the vertical direction (e.g., in the yz plane).

[0034] Figure 5 This is a schematic graph of the emission spectra of subpixels according to some embodiments. Emission spectra 200b, 200g, and 200r are schematically illustrated. In some embodiments, each of subpixels 110r1 and 110r2 has a substantially identical (e.g., identical or nominally identical or identical within a 10% or 5% variation) emission spectrum 200r (e.g., red), each of subpixels 110g1 and 110g2 has a substantially identical emission spectrum 200g (e.g., green), and each of subpixels 110b1 and 110b2 has a substantially identical emission spectrum 200b (e.g., blue).

[0035] Figures 7A to 7D The diagram shows normalized luminance distribution curves for a display system including a diffraction layer with linear diffraction elements, according to some embodiments. Pixel layout is typically as follows: Figure 4 As shown, the linear diffraction element is as follows: Figure 2 As shown. The brightness distribution was determined using conventional ray tracing techniques. A diffraction grating was simulated via rigorous coupled-wave analysis (RCWA), and scattering information was then compiled for use during ray tracing. Linear diffraction elements were modeled with an 800 nm pitch, 850 nm height, 500 nm ridge width, and low and high refractive indices of 1.52 and 1.72, respectively. The grating was set at a 100 μm spacing S1. Normalized brightness was determined as the brightness divided by the brightness of a comparison display system at a zero-degree polar angle, which had the same construction as the display system except that it did not include a light diffraction layer. In each case, the brightness of the display system was normalized by the brightness of the comparison display system having illuminated identical sub-pixels (e.g., only the first plurality of sub-pixels, only the second plurality of sub-pixels, or a combination of the first plurality of sub-pixels and the second plurality of sub-pixels).

[0036] Figures 7A to 7D The normalized luminance distributions 301v, 302v, 301v', 302v', 310v, 301h, 302h, 301h', 302h', and 310h of light leaving the display system in air are shown as a function of the light propagation angle (polar angle) in a first plane (yz plane or vertical plane for 301v, 302v, 301v', 302v', and 310v) or an orthogonal second plane (xz plane or horizontal plane for 301h, 302h, 301h', 302h', and 310h). Figure 7A Normalized luminance distributions of 301V and 302V and Figure 7B The normalized luminance distributions 301h and 302h are for when... Figure 2 The schematic illustration shows the case where the light diffraction layer 150 is included in the display system. Figure 7CThe normalized luminance distributions 301v' and 302v' and Figure 7D The normalized luminance distributions 301h' and 302h' are for display systems that include... Figure 2 The schematic illustration shows a similar light diffraction layer, but without a grating in region 112 of the pixel, when the light diffraction layer 150 is absent. The normalized brightness distributions 310v and 310h in the corresponding vertical and horizontal planes are for a comparative display system with the same construction as the display system but without the light diffraction layer. The light propagation angles (polar angles) in these figures are relative to the normal or thickness direction (…). Figure 2 (in the z-direction). When all sub-pixels in the first plurality of sub-pixels 110a of all pixels in the display area 101 emit light but no sub-pixels in the second plurality of sub-pixels 110b emit light, a normalized brightness distribution 301v, 301v', 301h, 301h' is generated; and when all sub-pixels in each of the first plurality of sub-pixels 110a and the second plurality of sub-pixels 110b of all pixels in the display area 101 emit light (or when all sub-pixels in all pixels of the display area 101 emit light), a normalized brightness distribution 302v, 302v', 302h, 302h' is generated. Due to the symmetry of the sub-pixel pattern, the normalized intensity 310v, 310h can be determined using the first plurality of sub-pixels 110a or a combination of the multiple sub-pixels 110a, 110b.

[0037] At least for light propagation angles relative to the thickness direction within the range of approximately -50° to approximately 50°, or approximately -55° to approximately 55°, or approximately -60° to approximately 60°, or approximately -65° to approximately 65°, the normalized luminance distributions 301v and 302v are substantially the same (e.g., identical, nominally identical, or identical within a 10% or 5% variation). At least for light propagation angles relative to the thickness direction within the range of approximately -50° to approximately 50°, or approximately -55° to approximately 55°, or approximately -60° to approximately 60°, or approximately -65° to approximately 65°, the normalized luminance distributions 301h and 302h are substantially the same. For light propagation angles relative to the thickness direction within most of the range of approximately -70° to approximately 70°, the normalized luminance distributions 301v' and 302v' are significantly different. For light propagation angles of approximately -45 degrees and approximately 45 degrees relative to the thickness direction, the normalized brightness distributions 301h' and 302h' are significantly different because the normalized intensities 301h' and 302h' differ from each other by more than 10% at each of these light propagation angles.

[0038] At least for light propagation angles relative to the thickness direction in the range of approximately -50 degrees to approximately 50 degrees (e.g., for light propagation angles in the range of approximately -55 degrees to approximately 55 degrees, or approximately -60 degrees to approximately 60 degrees, or approximately -65 degrees to approximately 65 degrees), the normalized luminance distributions 301v, 302v, 302v', and 310v (but not the normalized luminance distribution 301v') as a function of the light propagation angle relative to the thickness direction are substantially symmetrical about a second plane orthogonal to the first plane (e.g., the xz plane including a light propagation angle of 0 degrees) (e.g., symmetrical, or nominally symmetrical, or symmetrical with a deviation of at most approximately 10% or 5%). Symmetry about the plane should be understood as reflection symmetry about the plane. At least for light propagation angles relative to the thickness direction in the range of about -50 degrees to about 50 degrees (e.g., for light propagation angles in the range of about -55 degrees to about 55 degrees, or about -60 degrees to about 60 degrees, or about -65 degrees to about 65 degrees), the normalized luminance distributions 301h, 302h, 302h' and 310h (but not the normalized luminance distribution 301h') as a function of the light propagation angle relative to the thickness direction are substantially symmetrical about a first plane (e.g., the yz plane including a light propagation angle of 0 degrees) (e.g., symmetrical, or nominally symmetrical, or symmetrical with a deviation of up to about 10% or 5%).

[0039] Figure 8 A brightness distribution graph of a display system including a diffraction layer with a two-dimensional grating according to some embodiments is shown (see, for example...). Figure 4 ). Figure 8 The curve is as follows: Figures 7A to 7D The system is generally generated as described, except that a two-dimensional grating is used. This grating has square cells with a pitch of 800 nm and square pillars with dimensions (length in the x-direction, width in the y-direction, and height in the z-direction) of 400 nm × 400 nm × 1350 nm, set at a spacing S1 of 40 micrometers. The grating comprises two materials with low and high refractive indices of 1.52 and 1.74, respectively. Normalized brightness distributions 402v and 402h of light leaving the display system in air are shown as a function of the light propagation angle (polar angle) in the corresponding first (yz or vertical) and second (xz or horizontal) planes. The normalized brightness distribution 402v in the first plane is substantially symmetrical about the second plane, and the normalized brightness distribution 402h in the second plane is substantially symmetrical about the first plane. A normalized brightness distribution 410 of a comparative display system excluding the light diffraction layer is also shown, which is substantially the same in the first and second planes. For all green subpixels emitting light, normalized brightness distributions of 420v, 420h, and 410 are determined.

[0040] In some embodiments, for each of the first plurality of sub-pixels 110a and the combined plurality of sub-pixels 110a and 110b including the first plurality of sub-pixels and the second plurality of sub-pixels, light emitted by the sub-pixels (e.g., 141, 142, 143, 144) is transmitted by light diffraction layers 150, 150', 150'' and exits the display system toward the viewer 109 in the air, wherein at least some of the emitted light is diffracted by the light diffraction layers, wherein at least for the light propagation angle in the range of about -50 degrees to about 50 degrees, or about -55 degrees to about 55 degrees, or about -60 degrees to about 60 degrees, or about -65 degrees to about 65 degrees. The emitted light has a substantially identical (substantially identical for both first plurality of sub-pixels and combined plurality of sub-pixels) normalized brightness distribution as a function of the light propagation angle relative to the thickness direction in a first plane (yz plane), and / or wherein at least for the light propagation angle in the range of about -50 degrees to about 50 degrees, or about -55 degrees to about 55 degrees, or about -60 degrees to about 60 degrees, or about -65 degrees to about 65 degrees, the emitted light has a substantially identical (substantially identical for both first plurality of sub-pixels and combined plurality of sub-pixels) normalized brightness distribution as a function of the light propagation angle relative to the thickness direction in a second plane (xz plane). In other words, in some embodiments, the emitted light in at least one of the first plane and the second plane has a substantially identical normalized brightness distribution for both first plurality of sub-pixels and combined plurality of sub-pixels.

[0041] In some embodiments, for each of the first plurality of sub-pixels 110a and the combined plurality of sub-pixels 110a and 110b including the first plurality of sub-pixels and the second plurality of sub-pixels, light emitted by the sub-pixels (e.g., 141, 142, 143, 144) is transmitted by light diffraction layers 150, 150', 150'' and exits the display system toward the viewer 109 in the air, wherein at least some of the emitted light is diffracted by the light diffraction layers, wherein in the first plane, at least for light propagation angles in the range of about -50 degrees to about 50 degrees relative to the thickness direction (e.g., for those in the range of about -55 degrees to about 55 degrees, or about -50 degrees to about 50 ... The emitted light has a first brightness distribution as a function of the light propagation angle with respect to the thickness direction, which is substantially symmetrical about the second plane, at least for light propagation angles with respect to the thickness direction in the range of about -50 degrees to about 50 degrees (e.g., for light propagation angles in the range of about -55 degrees to about 55 degrees, or about -60 degrees to about 60 degrees, or about -65 degrees to about 65 degrees), the emitted light has a second brightness distribution as a function of the light propagation angle with respect to the thickness direction, which is substantially symmetrical about the first plane.

[0042] In some embodiments, the display system 100 includes a display area 101 configured to form an image 107 across the display area for viewing by a viewer 109, and includes a plurality of pixels 105 defining a light-emitting region (the region of sub-pixels 110) configured to emit light and a non-light-emitting region 120 not configured to emit light. Each pixel 105 includes a first plurality of non-overlapping sub-pixels 110a and a second plurality of non-overlapping sub-pixels 110b. Each of the first plurality of 110a and the second plurality of 110b includes at least three distinct sub-pixels (e.g., 110r1, 110g1, 110b1 and 110r2, 110g2, 110b2) having at least three different emission spectra (e.g., 200r, 200g, and 200b). Display system 100 includes light diffraction layers 150, 150', and 150'', configured between viewer 109 and display area 101, and disposed substantially parallel to and spaced apart from display area 101 along the thickness direction (z-direction) of the display system. Light diffraction layers 150, 150', and 150'' include a light diffraction region 152 configured to diffract light and a non-light diffraction region 154 not configured to diffract light. The light diffraction regions are aligned with a first non-emitting region of non-emitting region 120 and extend substantially together with it in length and width. The non-light diffraction regions are aligned with a region including a light-emitting region (region of sub-pixel 110) and a second non-emitting region of non-light-emitting region 120 (e.g., regions 121 and 111), and extend substantially together with it in length and width.

[0043] In some embodiments, the first non-emissive region and the second non-emissive region are non-overlapping regions selected from the non-emissive region 120, such that for each of the first plurality of sub-pixels 110a and the combined plurality of sub-pixels 110a, 110b including the first plurality of sub-pixels and the second plurality of sub-pixels, light emitted by the sub-pixels is transmitted by the light diffraction layers 150, 150', 150'' and exits the display system 100 toward the viewer in air, at least some of the emitted light is diffracted by the light diffraction layers, such that: in a first plane (xz plane) parallel to the thickness direction (z direction), at least for light propagation angles in the range of about -50 degrees to about 50 degrees (e.g., for about -55 degrees to about 55 degrees, or about -60 degrees to about 60 degrees, or about... The emitted light has a substantially identical (substantially identical for the first plurality of sub-pixels and for the combined plurality of sub-pixels) first normalized brightness distribution as a function of the light propagation angle relative to the thickness direction, at least for light propagation angles in the range of approximately -50 degrees to approximately 50 degrees (e.g., for light propagation angles in the range of approximately -55 degrees to approximately 55 degrees, or approximately -60 degrees to approximately 60 degrees, or approximately -65 degrees to approximately 65 degrees), the emitted light has a substantially identical (substantially identical for the first plurality of sub-pixels and for the combined plurality of sub-pixels) second normalized brightness distribution as a function of the light propagation angle relative to the thickness direction.

[0044] In some embodiments, the first non-emissive region and the second non-emissive region are non-overlapping regions selected from the non-emissive region, such that for each of the first plurality of sub-pixels 110a and the combined plurality of sub-pixels 110a, 110b including the first plurality of sub-pixels and the second plurality of sub-pixels, light emitted by the sub-pixels is transmitted by the light diffraction layers 150, 150', 150'' and exits the display system 100 toward the viewer in air, at least some of the emitted light is diffracted by the light diffraction layers, such that: in a first plane parallel to the thickness direction (z direction) (e.g., the xz plane), at least for light propagation angles in the range of about -50 degrees to about 50 degrees relative to the thickness direction (e.g., for those in the range of about -55 degrees to about 55 degrees), The emitted light has a first brightness distribution as a function of the light propagation angle relative to the thickness direction, which is substantially symmetrical about a second plane (e.g., the yz plane) that is parallel to the thickness direction and orthogonal to the first plane; and in the second plane, at least for light propagation angles in the range of approximately -50 degrees to 50 degrees relative to the thickness direction (e.g., for light propagation angles in the range of approximately -55 degrees to 55 degrees, or approximately -60 degrees to 60 degrees, or approximately -65 degrees to 65 degrees), the emitted light has a second brightness distribution as a function of the light propagation angle relative to the thickness direction, which is substantially symmetrical about the first plane.

[0045] The optical diffraction region 152 may include any diffraction structure described elsewhere. In some embodiments, the optical diffraction region 152 includes a plurality of substantially parallel linear diffraction elements (see, for example) extending along a first in-plane direction (x-direction) and arranged along a second in-plane direction (y-direction) orthogonal to the first direction. Figure 2 In some embodiments, the optical diffraction region 152 includes a two-dimensional grating comprising a plurality of diffraction elements arranged along each of a first and a second direction in an orthogonal plane (see, for example...). Figure 3 ).

[0046] For any of the display systems described in this specification, the light diffraction layers 150, 150', 150'' can increase the on-axis brightness of light leaving the display system by, for example, at least about 20%. In some embodiments, for at least the same sub-pixel (e.g., 110g1, 110g2) of at least three different sub-pixels of each of the first plurality of sub-pixels 110a and the second plurality of sub-pixels 110b of each pixel in pixel 105, when light emitted by the sub-pixel is transmitted by the light diffraction layers 150, 150', 150'' and leaves the display system in air toward an observer, the light diffraction layers 150, 150', 150'' increase the on-axis (e.g., along the z-axis) brightness of the emitted light by at least about 20%, 25%, 30%, 35%, or 40%. For example, this increase can be up to about 100%, 90%, or 80%. This increase is relative to a display system without the light diffraction layers 150, 150', 150''. For example, the light diffraction layers 150, 150', and 150'' increasing the on-axis brightness of the emitted light by at least 20% means that the on-axis brightness is at least 1.2 times that of the corresponding on-axis brightness of the comparison display system, which has the same construction as the display system except that the comparison display system does not include the light diffraction layers 150, 150', and 150''. In other words, the normalized brightness relative to the comparison display system at a light propagation angle of 0 degrees can be at least 1.2.

[0047] For any of the display systems described in this specification, the light diffraction layers 150, 150', 150'' can cause the brightness of light leaving the display system to have full width at a specified fraction of maximum brightness in a plane, which is substantially greater than an orthogonal plane for a given plane. For example, the specified fraction could be ½ or ¾. In some embodiments, for at least the same sub-pixel (e.g., 110g1, 110g2) of at least three different sub-pixels of each of the first plurality of sub-pixels 110a and the second plurality of sub-pixels 110b of each pixel in pixel 105, when light emitted by the sub-pixel is transmitted by the light diffraction layers 150, 150', 150'' and leaves the display system toward the viewer in air, the outgoing light has a brightness as a function of the light propagation angle relative to the thickness direction (z direction), which has full width at a maximum value of less than about 50 degrees in a first plane (e.g., the yz plane) and at a maximum value of greater than about 80 degrees in a second plane (e.g., the xz plane). The first and second planes can be orthogonal to each other and parallel to the thickness direction. In the first plane, the full width at the maximum value of ¾ can be less than approximately 45 degrees, 40 degrees, or 35 degrees. In the second plane, the full width at the maximum value of ¾ can be greater than approximately 90 degrees, 100 degrees, 110 degrees, 120 degrees, 130 degrees, or 140 degrees. For example, in Figure 7AIn the first (vertical) plane, the normalized luminance 302v has a maximum value of approximately 1.57 at a light propagation angle of approximately 0 degrees and a full width of approximately 1.18 at a maximum value of approximately 29 degrees. Figure 7B In the second (horizontal) plane, the normalized luminance 302h has a maximum value of approximately 1.84 at a light propagation angle of approximately ±40 degrees and a full width of approximately 1.38 at a maximum value of approximately 100 degrees. As another example, in Figure 8 In the first (vertical) plane, the normalized luminance 402v has a maximum value of about 1.5 at a light propagation angle of about 0 degrees and a full width (about 1.1) at a maximum value of about 35 degrees, and the normalized luminance 402h in the second (horizontal) plane has a maximum value of about 1.5 at a light propagation angle of about 0 degrees and a full width (about 1.1) at a maximum value of about 150 degrees.

[0048] Terms such as “about” will be understood in the context in which they are used and described in this specification by those skilled in the art. If the use of “about” to express quantities of characteristic size, quantity, and physical properties is unclear to those skilled in the art in the context in which it is used and described in this specification, then “about” will be understood to mean within 10% of the specified value. A quantity given a specified value as “about” can be precisely the specified value. For example, if it is unclear to those skilled in the art in the context in which it is used and described in this specification, 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 can be 1.

[0049] The term “substantially” will be understood by those skilled in the art in the context of its use and description in this specification. If, in the context of its use and description in this specification, the use of “substantially” regarding a property or characteristic is not readily apparent to those skilled in the art, and when the opposite meaning of such property or characteristic is clear to those skilled in the art, the term “substantially” will be understood to mean that the property or characteristic is more pronounced than its opposite meaning.

[0050] All cited references, patents, and patent applications are incorporated herein by reference in their entirety in a consistent manner. In the event of any inconsistency or contradiction between the incorporated references and this application, the information in the foregoing description shall prevail.

[0051] Unless otherwise indicated, the description of elements in the accompanying drawings should be understood to apply equally to corresponding elements in the other drawings. While specific embodiments have been illustrated and described herein, those skilled in the art will recognize that various alternative and / or equivalent embodiments may be used instead of the illustrated and described embodiments without departing from the scope of this disclosure. This application is intended to cover any modifications, variations, or combinations of the specific embodiments discussed herein. Therefore, this disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. A display system, the display system comprising: A display area comprising a plurality of pixels configured to form an image across the display area for viewing by a viewer, each pixel comprising three or more sub-pixels, wherein for each pixel, the sub-pixels define a non-overlapping first intra-pixel region and a second intra-pixel region, and the pixels define a non-overlapping first inter-pixel region and a second inter-pixel region, each of the first intra-pixel region and the second intra-pixel region and the first inter-pixel region and the second inter-pixel region having no luminous sub-pixels, the sub-pixels, the first intra-pixel region and the first inter-pixel region defining a first combined region, and the second intra-pixel region and the second inter-pixel region defining a second combined region; and A light diffraction layer is configured between the viewer and the display area and is disposed substantially parallel to the display area and spaced apart from the display area along the thickness direction of the display system. The light diffraction layer includes a light diffraction region configured to diffract light and a non-light diffraction region not configured to diffract light. The non-light diffraction region and the light diffraction region of the light diffraction layer are aligned with and extend substantially together with the corresponding first and second combined regions in length and width, such that for each sub-pixel, for a first light emission angle greater than about 10 degrees relative to the thickness direction and a second light emission angle less than about -10 degrees relative to the thickness direction, and for a first plane and a second plane orthogonal to each other and parallel to the thickness direction: Light emitted by the sub-pixel in the first plane at each of the first emission angle and the second emission angle is diffractedly transmitted by the diffraction region of the light diffraction layer; and Light emitted by the sub-pixel in the second plane at each of the first emission angle and the second emission angle is non-diffracted through the non-diffracting region of the optical diffraction layer.

2. The display system of claim 1, wherein each pixel comprises a first plurality of non-overlapping sub-pixels and a second plurality of sub-pixels, each of the first plurality of sub-pixels and the second plurality of sub-pixels comprising at least three different sub-pixels having at least three different emission spectra.

3. The display system of claim 2, wherein for each of the first plurality of sub-pixels and the combined plurality of sub-pixels including the first plurality of sub-pixels and the second plurality of sub-pixels, light emitted by the sub-pixels is transmitted by the light diffraction layer and exits the display system toward the viewer in air, at least some of the emitted light is diffractedly transmitted by the light diffraction layer, and the outgoing light has substantially the same normalized brightness distribution as a function of the light propagation angle relative to the thickness direction in the first plane, at least for light propagation angles in the range of about -50 degrees to about 50 degrees.

4. The display system of claim 2, wherein for each of the first plurality of sub-pixels and the combined plurality of sub-pixels including the first plurality of sub-pixels and the second plurality of sub-pixels, light emitted by the sub-pixels is transmitted by the light diffraction layer and exits the display system toward the viewer in air, at least some of the emitted light is diffractedly transmitted by the light diffraction layer, and the outgoing light has substantially the same normalized brightness distribution as a function of the light propagation angle relative to the thickness direction in the second plane, at least for light propagation angles in the range of about -50 degrees to about 50 degrees.

5. The display system of claim 2, wherein the pixels are arranged in rows of pixels extending along a first direction in the plane, each row of pixels comprising rows of sub-pixels among the first plurality of sub-pixels and rows of sub-pixels among the second plurality of sub-pixels, the average spacing between rows of sub-pixels within a row of pixels being less than the average spacing between adjacent rows of pixels.

6. The display system of claim 5, wherein the light diffraction region comprises a plurality of substantially parallel linear diffraction elements extending along the first direction and arranged along a second direction in a plane orthogonal to the first direction.

7. The display system according to any one of claims 1 to 5, wherein the light diffraction region comprises a two-dimensional grating, the two-dimensional grating comprising a plurality of diffraction elements arranged along each of two orthogonal in-plane directions.

8. A display system, the display system comprising: A display area is configured to form an image across the display area for a viewer to view and includes a plurality of pixels, the plurality of pixels defining an emitting area configured to emit light and a non-emitting area not configured to emit light, each pixel including a first plurality of sub-pixels and a second plurality of sub-pixels that do not overlap, each of the first plurality of sub-pixels and the second plurality of sub-pixels including at least three different sub-pixels having at least three different emission spectra; and A light diffraction layer is configured between the viewer and the display area, and is substantially parallel to and spaced apart from the display area along the thickness direction of the display system. The light diffraction layer includes a light diffraction region configured to diffract light and a non-light diffraction region not configured to diffract light. The light diffraction region is aligned with and extends substantially co-located with a first non-emitting region of the non-emitting region in length and width. The non-light diffraction region is aligned with and extends substantially co-located with a second non-emitting region comprising the light-emitting region and the non-light-emitting region in length and width. The first non-emitting region and the second non-emitting region are non-overlapping regions selected from the non-emitting region, such that for each of the first plurality of sub-pixels and the combined plurality of sub-pixels including the first plurality of sub-pixels and the second plurality of sub-pixels, light emitted by the sub-pixels is transmitted by the light diffraction layer and leaves the display system in the air toward the viewer, and at least some of the emitted light is diffractedly transmitted by the light diffraction layer, such that: In a first plane parallel to the thickness direction, at least for light propagation angles ranging from about -50 degrees to about 50 degrees, the emitted light has substantially the same first normalized brightness distribution as a function of the light propagation angle relative to the thickness direction; and In a second plane parallel to the thickness direction and orthogonal to the first plane, at least for light propagation angles in the range of about -50 degrees to about 50 degrees, the emitted light has substantially the same second normalized brightness distribution as a function of the light propagation angle relative to the thickness direction.

9. The display system of claim 8, wherein for at least the same sub-pixel among the at least three different sub-pixels of each of the first plurality of sub-pixels and the second plurality of sub-pixels of each pixel, when light emitted by the sub-pixel is transmitted by the light diffraction layer and leaves the display system toward the viewer in the air, the light diffraction layer increases the on-axis brightness of the emitted light by at least 20%.

10. The display system of claim 8 or 9, wherein the light diffraction region comprises a plurality of substantially parallel linear diffraction elements extending along a first direction in a plane and arranged along a second direction in a plane orthogonal to the first direction.

11. The display system according to claim 8 or 9, wherein the light diffraction region comprises a two-dimensional grating, the two-dimensional grating comprising a plurality of diffraction elements arranged along each of a first direction and a second direction in an orthogonal plane.

12. A display system, the display system comprising: A display area is configured to form an image across the display area for a viewer to view and includes a plurality of pixels, the plurality of pixels defining an emitting area configured to emit light and a non-emitting area not configured to emit light, each pixel including a first plurality of sub-pixels and a second plurality of sub-pixels that do not overlap, each of the first plurality of sub-pixels and the second plurality of sub-pixels including at least three different sub-pixels having at least three different emission spectra; and A light diffraction layer is configured between the viewer and the display area, and is substantially parallel to and spaced apart from the display area along the thickness direction of the display system. The light diffraction layer includes a light diffraction region configured to diffract light and a non-light diffraction region not configured to diffract light. The light diffraction region is aligned with and extends substantially co-located with a first non-emitting region of the non-emitting region in length and width. The non-light diffraction region is aligned with and extends substantially co-located with a second non-emitting region comprising the light-emitting region and the non-light-emitting region in length and width. The first non-emitting region and the second non-emitting region are non-overlapping regions selected from the non-emitting region, such that for each of the first plurality of sub-pixels and the combined plurality of sub-pixels including the first plurality of sub-pixels and the second plurality of sub-pixels, light emitted by the sub-pixels is transmitted by the light diffraction layer and leaves the display system in the air toward the viewer, and at least some of the emitted light is diffractedly transmitted by the light diffraction layer, such that: In a first plane parallel to the thickness direction, at least for light propagation angles in the range of approximately -50 degrees to approximately 50 degrees relative to the thickness direction, the emitted light has a first brightness distribution as a function of the light propagation angle relative to the thickness direction, the first brightness distribution being substantially symmetrical about a second plane parallel to the thickness direction and orthogonal to the first plane; and In the second plane, at least for the light propagation angle in the range of about -50 degrees to about 50 degrees with respect to the thickness direction, the emitted light has a second brightness distribution as a function of the light propagation angle with respect to the thickness direction, the second brightness distribution being substantially symmetrical about the first plane.

13. The display system of claim 12, wherein for at least the same sub-pixel among the at least three different sub-pixels of each of the first plurality of sub-pixels and the second plurality of sub-pixels of each pixel, when light emitted by the sub-pixel is transmitted by the light diffraction layer and leaves the display system toward the viewer in the air, the light diffraction layer increases the on-axis brightness of the emitted light by at least 20%.

14. The display system of claim 12 or 13, wherein the light diffraction region comprises a plurality of substantially parallel linear diffraction elements extending along a first direction in a plane and arranged along a second direction in a plane orthogonal to the first direction.

15. The display system of claim 12 or 13, wherein the light diffraction region comprises a two-dimensional grating, the two-dimensional grating comprising a plurality of diffraction elements arranged along each of a first direction and a second direction in an orthogonal plane.

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