Optical layers and optical systems

Abstract

An optical system includes a lens layer including a plurality of microlenses arranged along orthogonal first and second directions; and at least one optically opaque mask layer spaced apart from the lens layer and defining therein a plurality of through openings arranged along the first and second directions. There is a one-to-one correspondence between the microlenses and the openings, such that for each microlens, the microlens and the corresponding opening are substantially centered on a line having the same oblique angle with the lens layer. The optical layer may include a lens layer and an optically opaque mask layer embedded in the optical layer.

Description

Background Art

[0001] A device including a liquid crystal display may include a fingerprint sensor behind the display. Summary of the invention

[0002] In some aspects, the present disclosure provides an optical system comprising a lens layer including a plurality of microlenses arranged along orthogonal first and second directions; and at least one optically opaque mask layer spaced apart from the lens layer and defining therein a plurality of through openings arranged along the first and second directions. There may be a one-to-one correspondence between the microlenses and the openings, such that for each microlens, the microlens and the corresponding opening are substantially centered on a straight line having the same oblique angle with the lens layer. The optical layer may include a lens layer and an optically opaque mask layer embedded in the optical layer.

[0003] In some aspects, the present disclosure provides an optical system, the optical system comprising: a lens layer, the lens layer comprising a plurality of microlenses arranged along orthogonal first and second directions; an optically opaque first mask layer, the optically opaque first mask layer being spaced apart from the lens layer and defining therein a plurality of through first openings arranged along the first and second directions; and an optically opaque second mask layer, the optically opaque second mask layer being spaced apart from the lens layer and the first mask layer and defining therein a plurality of through second openings arranged along the first and second directions. The first mask layer is disposed between the lens layer and the second mask layer. There is a one-to-one correspondence between the microlenses and the first and second openings, such that for each microlens, the microlens and the corresponding first and second openings are substantially centered on a straight line having the same oblique angle with the lens layer. When image light carrying an image is incident on the microlens along a straight line with the image light substantially filling the microlens, greater than about 35%, or greater than about 40%, or greater than about 45%, or greater than about 50% of the incident image light is transmitted by the second opening. At least one of the first opening and the second opening is sized so as to reduce image quality degradation due to the microlens.

[0004] In some aspects, the present disclosure provides an optical layer comprising: a structured first major surface and an opposing second major surface, the structured first major surface comprising a plurality of microlenses arranged along orthogonal first and second directions; and an embedded optically opaque first mask layer, the embedded optically opaque first mask layer being disposed between the first major surface and the second major surface and spaced apart from the first major surface and the second major surface. The first mask layer defines a plurality of through first openings arranged along the first and second directions therein. There may be a one-to-one correspondence between the microlenses and the first openings. For each first opening of at least a majority of the first openings, the first opening defines a voided region having a maximum thickness greater than an average thickness of the first mask layer.

[0005] In some aspects, the present disclosure provides an optical layer, the optical layer comprising: a structured first major surface and an opposite second major surface, the structured first major surface comprising a plurality of microlenses arranged along an orthogonal first direction and a second direction; and an embedded optically opaque first mask layer, the embedded optically opaque first mask layer being disposed between the first major surface and the second major surface and spaced apart from the first major surface and the second major surface. The first mask layer defines a plurality of through first openings arranged along the first direction and the second direction therein. There may be a one-to-one correspondence between the microlenses and the first openings. For each first opening in at least most of the first openings, the first opening defines a voided region, the voided region having a top major surface facing the first major surface and an opposite bottom major surface facing the second major surface. In a cross-section of the optical layer substantially perpendicular to the optical layer, the optical layer comprises a plurality of nanoparticles concentrated along at least one of the top major surface and the bottom major surface of the voided region. In some embodiments, the first mask layer comprises a first material, and the nanoparticles comprise at least one of the first material or an oxide of the first material.

[0006] In some aspects, the present disclosure provides an optical layer, the optical layer comprising: a structured first major surface and an opposite second major surface, the structured first major surface comprising a plurality of microlenses arranged along orthogonal first and second directions; and an embedded optically opaque first mask layer, the embedded optically opaque first mask layer being disposed between the first major surface and the second major surface and spaced apart from the first major surface and the second major surface. The first mask layer defines a plurality of through first openings arranged along the first and second directions therein. There may be a one-to-one correspondence between the microlenses and the first openings. For each first opening in at least a majority of the first openings, the first opening defines a voided region, the voided region having a top major surface facing the first major surface and an opposite bottom major surface facing the second major surface. In a cross-section of the optical layer substantially perpendicular to the optical layer, the spacing of the top surface and the bottom surface closer to the center of the voided region is greater than the spacing closer to the edge of the voided region. At least one of the top major surface and the bottom major surface may have a surface roughness in the range of 10 nm to 200 nm.

[0007] In some aspects, the present disclosure provides a method of manufacturing an optical layer. The optical layer can be any of the optical layers described elsewhere herein. The method can include irradiating an embedded optically opaque mask layer through a plurality of microlenses to form a plurality of through first openings in the mask layer.

[0008] In some aspects, the present disclosure provides an optical system comprising an optical element and a refractive component. The optical element comprises a lens layer comprising a plurality of microlenses arranged along an orthogonal first direction and a second direction; and an optically opaque first mask layer, which is spaced apart from the lens layer and defines a plurality of through first openings arranged along the first direction and the second direction. There is a one-to-one correspondence between the microlenses and the first openings, so that for each microlens, the microlens and the corresponding first opening are substantially centered on a straight line. Each straight line is at the same oblique angle to the lens layer. The refractive component extends along the first direction and the second direction and is disposed near the optical element so that for at least one first light beam incident on the refractive component along a third direction substantially orthogonal to the lens layer, the refractive component splits the first light beam into 2 to 9 beam segments that leave the refractive component along corresponding 2 to 9 main directions. The first main direction of the 2 to 9 main directions is substantially parallel to each straight line.

[0009] In some aspects, the present disclosure provides an optical system comprising a refractive component, an optical element, a light source, and an optical sensor. The refractive component extends along orthogonal first and second directions, so that for at least one first light beam incident on the refractive component along a third direction substantially orthogonal to the first and second directions, the refractive component splits the first light beam into 2 to 9 beam segments that leave the refractive component along corresponding 2 to 9 principal directions. The 2 to 9 principal directions include the first principal direction. The optical element is disposed near the refractive component so that at least 45% of the light in the beam segment incident on the optical element along the first principal direction (but not any other principal direction) is transmitted through the optical element. The light source is disposed to emit light along a direction substantially parallel to a second principal direction among the 2 to 9 principal directions. The optical sensor is disposed to receive light transmitted through the optical element along the first principal direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic cross-sectional view of an optical system;

[0011] Figure 2A-2C schematically illustrates light incident on a microlens;

[0012] Figure 3 is a schematic graph of the intensity distribution of light transmitted through a microlens;

[0013] Figure 4 is a schematic cross-sectional view of an optical element or layer;

[0014] Figure 5A-5D is a schematic cross-sectional view of a portion of an optical element or layer;

[0015] Figure 6 is a schematic cross-sectional view of an optical system including an optical element or layer;

[0016] Figure 7 is a schematic top view projection of a microlens array and a through opening;

[0017] Figure 8-Figure 9 is a schematic cross-sectional view of an optical system;

[0018] Figure 10A-10B is a schematic diagram of the maximum projected area of ​​the optical element and the refractive component;

[0019] Fig.11 is a schematic cross-sectional view of a refractive component;

[0020] Figure 12A-12C is a schematic conoscopic diagram;

[0021] Fig.13A is a schematic cross-sectional view of an optical element or layer including a microlens and an optical decoupling structure;

[0022] Fig. 13B is attached to the adjacent layer Fig.13A Schematic cross-sectional view of an optical element or layer;

[0023] Fig.14 is a schematic cross-sectional view of an optical element or layer including two pluralities of microlenses;

[0024] Figure 15-17 is a graph of the calculated point spread function of the optical system; and

[0025] Figure 18-Figure 20 is an image of a cross section through an opening in the embedded mask layer. DETAILED DESCRIPTION

[0026] In the following description, reference is made to the accompanying drawings, which form a part of the present invention and in which various embodiments are shown by way of example. The drawings are not necessarily drawn to scale. It should be understood that other embodiments may be conceived and carried out without departing from the scope or essence of the present description. Therefore, the following specific embodiments should not be considered to have a limiting meaning.

[0027] For some applications, such as smartphone or tablet computer applications, it is desirable to place the fingerprint sensor behind a liquid crystal display (LCD). However, a liquid crystal display typically includes a refractive component, such as a crossed prismatic film, behind the liquid crystal display panel. Light reflected from the fingerprint is typically split into multiple beam segments by the refractive component, and this can degrade the quality of the optical image of the fingerprint when incident on the sensor. According to some embodiments, optical elements, layers, and systems are provided that avoid or substantially reduce such image quality degradation.

[0028] Figure 1 1 is a schematic cross-sectional view of an optical system 150 including a lens layer 110, an optically opaque first mask layer 120, and an optically opaque second mask layer 125. In some embodiments, the optical element or layer 100 includes the lens layer 110 and each of the first mask layer 120 and the second mask layer 125. The optical element or layer 100 may have a structured first major surface 103 and an opposing second major surface 104. In other embodiments, different optical elements may include one or more of the different layers. For example, a first optical element may include a lens layer 110 and a first mask layer 120, and a second optical element spaced apart from the first optical element may include a second mask layer 125.

[0029] The lens layer 110 includes a plurality of microlenses 102 arranged (e.g., in a regular array) along orthogonal first and second directions (x - direction and y - direction). The optically opaque first mask layer 120 is spaced apart from the lens layer 110 by a distance d1, which can be, for example, in the range of 2 micrometers to 35 micrometers. The optically opaque first mask layer 120 defines therein a plurality of through - going first openings 122 arranged along the first and second directions. The optically opaque second mask layer 125 is spaced apart from the lens layer 110 and the first mask layer 120 and defines therein a plurality of through - going second openings 127 arranged along the first and second directions. The first mask layer 120 is disposed between the lens layer 100 and the second mask layer 125. The second mask layer 125 is spaced apart from the first mask layer 120 by a distance d2, which can be, for example, in the range of 1 micrometer to 20 micrometers. In some embodiments, d2 < d1, or d2 < 0.7d1, or d2 < 0.5d1. There can be a one - to - one correspondence between the microlenses 102 and the first openings 122 and the second openings 127 (i.e., for each microlens 102, one first opening 122 and one second opening 127 correspond to the microlens), such that for each microlens 102, the microlens and the corresponding first opening 122 and second opening 127 are centered on a straight line 140 that is at substantially the same oblique angle θ with respect to the lens layer 110. For example, microlens 102a corresponds to first opening 122a and second opening 127a, and microlens 102a and the corresponding first opening 122a and second opening 127a are centered on straight line 140a. For example, when a line passes through the center of a lens or an opening or within about 20%, or about 10%, or about 5% of the diameter of the lens or opening respectively when passing through the center, the lens or opening can be described as being centered on a straight line 140.

[0030] A microlens is generally a lens having at least two orthogonal dimensions (e.g., height and diameter, or diameters along two axes) less than 1 mm and greater than 100 nm. For example, a microlens can have an average diameter in the range of 10 micrometers to 100 micrometers. For example, a microlens can have an average radius of curvature in the range of 5 micrometers to 50 micrometers. For example, a microlens can be a spherical microlens or an aspherical microlens. It has been found that aspherical microlenses can provide improved optical properties (e.g., improved focusing) for light incident at a desired off - axis angle (e.g., along line 140). For example, the optical element or layer 100 or other optical elements or layers described elsewhere herein can have a total thickness in the range of 10 micrometers to 100 micrometers.

[0031] When less than 20%, or less than 15%, or less than 10%, or less than 5%, or less than 3% of the non-polarized visible light vertically incident on the layer in the area between the openings is transmitted through the layer, the mask layer can be described as optically opaque. The mask layer can be optically absorbing or optically reflective. Suitable mask layers include metal layers (e.g., vapor deposited or sputtered), metal oxide layers, dark material (e.g., including optically absorbing dyes) coatings, and optically absorbing or reflecting films. The mask layer may have a sufficient thickness to make the material appropriately optically opaque. For example, the average thickness t and t' of the mask layer may each be in the range of 5nm to 5 microns. In some embodiments, t and / or t' are in the range of, for example, 10nm to 500nm, or 10nm to 150nm, or 15nm to 100nm, or 15nm to 50nm, or 20nm to 40nm.

[0032] A first mask layer 120 and a second mask layer 125 may be included to limit light transmitted through the optical element to substantially only light along line 140. The second mask layer 125 may be included to reduce crosstalk in the event that light incident on one microlens is transmitted through an opening corresponding to another microlens. For example, light 108 that would otherwise cause crosstalk is blocked by the second mask layer 125. In some embodiments, the second mask layer 125 is omitted. In some embodiments, as further described elsewhere herein, a pixelated photosensor may be used in place of the second mask layer 125. Related optical elements are described in International Application No. IB2019 / 056781 (Yang et al.).

[0033] In some embodiments, the first opening 122 is a physical opening. The physical opening has a material that is removed from the mask layer so that a physical hole exists. For example, a physical opening or hole can be formed in an optically opaque layer by laser ablation. In some embodiments, the first opening is an optical opening. The optical opening has a material that is processed so that light can be transmitted through the optical opening even if the material is present in the optical opening. For example, an optical opening can be formed in an optically opaque layer by bleaching (for example, an optically opaque layer incorporating a dye can be photobleached or thermally bleached so that the bleached dye is no longer optically absorbed). The optical opening can be formed in a birefringent reflective film by reducing the birefringence in the opening, as generally described in U.S. Pat. No. 9,575,233 (Merrill et al.). An absorbing outer coating can be optionally applied to the optical film to increase the absorption of energy from the laser. In some embodiments, the second opening 127 is a physical opening. In some embodiments, the second opening 127 is an optical opening. In some embodiments, the average diameter d of the first openings 122 ranges from, for example, 500 nm to 50 microns, or 1 micron to 40 microns, or 2 microns to 30 microns, or 3 microns to 20 microns, or 5 microns to 15 microns. In some embodiments, the average diameter d' of the second openings 127 ranges from, for example, 500 nm to 50 microns, or 1 micron to 40 microns, or 2 microns to 30 microns, or 3 microns to 20 microns, or 5 microns to 15 microns.

[0034] In some embodiments, for each of at least a majority of first openings 122, the first openings define a voided region. The voided region may have a top major surface facing first major surface 103 and an opposing bottom major surface facing second major surface 104. In some embodiments, in a cross-section of the optical layer substantially perpendicular to the optical layer, the optical layer includes a plurality of nanoparticles concentrated along at least one of the top major surface and the bottom major surface of the voided region, as further described elsewhere. In some embodiments, in a cross-section of the optical layer substantially perpendicular to the optical layer, the top and bottom surfaces are spaced farther apart nearer the center of the voided region than nearer the edge of the voided region. In some such embodiments or in other embodiments, the surface roughness of at least one of the top and bottom major surfaces is in a range of 10 nm to 200 nm or in a range described elsewhere.

[0035] In some embodiments, the additional layer 244 is disposed on the second mask layer 125 opposite the first mask layer 120. In other embodiments, the additional layer 244 is omitted. In some embodiments, for each second opening in at least a majority of the second openings 127, the second openings define a voided region. The voided region may have a top major surface facing the first major surface 103 and an opposing bottom major surface facing the second major surface 104. In some embodiments, in a cross-section of the optical layer substantially perpendicular to the optical layer, the optical layer includes a plurality of nanoparticles concentrated along at least one of the top major surface and the bottom major surface of the voided region, as further described elsewhere. In some embodiments, in a cross-section of the optical layer substantially perpendicular to the optical layer, the spacing of the top surface and the bottom surface closer to the center of the voided region is greater than the spacing closer to the edge of the voided region. In some such embodiments or in other embodiments, the surface roughness of at least one of the top major surface and the bottom major surface is in the range of 10 nm to 200 nm or in the range described elsewhere.

[0036] In some embodiments, additional layers are included. For example, additional layers (such as primer layers or tie layers) may be provided on the Figure 1 At any one or more interfaces between adjacent layers depicted in order to improve bonding between the adjacent layers.

[0037] For ease of description, spatially relative terms (including but not limited to "top", "bottom") are used to describe the spatial relationship of one element relative to another element. Such spatially relative terms encompass different orientations of the device when in use or operation in addition to the specific orientations depicted in the drawings and described herein. For example, if an object depicted in a drawing is turned over or inverted, portions previously described as being below or beneath other elements would now be above those other elements.

[0038] Figure 2A is a schematic diagram of light 130 incident on microlens 102 according to some embodiments. Figure 2B is a schematic diagram of light 130 incident on a microlens 102, wherein the microlens causes image quality degradation, according to some embodiments. Figure 2C1 is a schematic diagram of light 130 incident on a microlens 102, wherein at least one of first opening 122 and second opening 127 is sized to reduce image quality degradation due to the microlens. In some embodiments, when image light 130 carrying image 133 is incident on microlens 102 along line 140 with image light 130 substantially filling microlens 102, greater than about 35%, or greater than about 40%, or greater than about 45%, or greater than about 50% of the incident image light is transmitted by second opening 127. In some embodiments, at least one of first opening 122 and second opening 127 is sized to reduce image quality degradation due to the microlens. For example, the image light may be described as substantially filling the microlens when the image light fills the microlens, or when the image light fills at least 70%, or at least 80%, or at least 90% of the outer surface area of ​​the microlens.

[0039] Figure 3 is a schematic graph of the intensity distribution at a nominal image plane of light transmitted through a microlens causing image quality degradation. The diameter D of the opening in the mask layer is shown, which is sized so as to reduce image quality degradation due to the microlens. For example, a microlens can cause image quality degradation when the surface of the microlens deviates from an ideal shape due to manufacturing constraints. For example, a tool for forming a microlens may have a surface formed by removing material from a layer that produces multiple facets that approximately, but not exactly, follow the ideal shape of the microlens.

[0040] In some embodiments, the optical system is configured to detect fingerprints. Light propagating through the optical system from any point at the front surface of the display panel preferably has a limited spatial range when incident on the fingerprint sensor so as to form a desired (e.g., suitably clear) fingerprint image. This spatial range can be quantified by the point spread function of the optical system. The greater the spatial spread of the point spread function, the blurrier the fingerprint image. According to some embodiments, it has been found that including an optical element as described herein in the optical system can reduce the width of the point spread function. In some embodiments, the optical system has a point spread function for light incident on the optical system from a Lambertian point source, which point spread function is provided in the optical element (see, e.g., Figure 8-Figure 9 ) has a full width at half maximum (FWHM) of less than about 300 microns, or less than about 200 microns, or less than about 150 microns, or less than about 100 microns at the optical sensor behind it.

[0041] As further described elsewhere herein (see e.g. Figure 8-Figure 9), in some embodiments, the optical element 100 (e.g., or 300) includes a lens layer 110 and a first mask layer 120 and a second mask layer 125, and the optical system 150 further includes: a refractive component 160 extending along the first direction and the second direction and disposed near the optical element 100, so that for at least one first light beam 230 incident on the refractive component along a third direction (-z direction) substantially orthogonal to (e.g., within 30 degrees, or within 20 degrees, or within 10 degrees) the lens layer 110, the refractive component splits the first light beam into 2 to 9 beam segments 112, 114 that leave the refractive component along corresponding 2 to 9 main directions 131, 132, the first main direction 131 of the 2 to 9 main directions being substantially parallel to (e.g., within 30 degrees, or within 20 degrees, or within 10 degrees) each straight line 140. For example, the at least one first light beam 230 can be any light beam having a width greater than the width of a prism (or other refractive element) in the refractive component. Other beams of narrower width may be split into fewer than 2 to 9 principal directions. Each beam segment is a transmitted portion of the incident beam that propagates generally in the same direction, referred to as the principal direction. The beam segments and principal directions can be identified from a conoscopic diagram of the transmitted light intensity, for example, as further described elsewhere herein (see, e.g., Figure 12A-12C ).

[0042] In some embodiments, the optical system 150 further includes a liquid crystal display 270 extending along the first direction and the second direction, a light guide 265 configured to illuminate the liquid crystal display, a refractive component 160 disposed between the liquid crystal display 270 and the light guide 265, and an optical sensor 145 disposed near the light guide 265 and opposite to the liquid crystal display 270 (see, e.g., Fig. 9 In some embodiments, the optical element 100 (e.g., or 300) including the lens layer 110 and the first mask layer 120 and the second mask layer 125 is disposed between the light guide 265 and the optical sensor 145 such that the second mask layer 125 faces the optical sensor 145 (e.g., for example, Figure 1 and Figure 8 The optical element 300 is oriented as indicated by the xyz coordinate system, Figure 1 The optical element or layer 100 may be as Figure 8 Place as shown).

[0043] In some embodiments, each sublayer of the optical element 100 (e.g., the lens layer 110, the first mask layer 120, and the second mask layer 125) is bonded to an adjacent layer of the optical element 100. In such embodiments, the optical element 100 may be referred to as an optical layer. In some embodiments, the first mask layer 120 is embedded in the optical layer. In some embodiments, the additional layer 244 is disposed on the second mask layer 125 opposite the first mask layer 120, such that the second mask layer 125 is also an embedded layer. In some embodiments, the second mask layer 125 may be omitted.

[0044] Figure 4 is a schematic cross-sectional view of an optical element or layer 200. In some embodiments, the optical element or layer 200 includes a structured first major surface 103 and an opposite second major surface 104, wherein the structured first major surface 103 includes a plurality of microlenses 102 arranged along orthogonal first and second directions (x-direction and y-direction). The optical layer also includes an embedded optically opaque first mask layer 120, which is disposed between the first major surface 103 and the second major surface 104 and is spaced apart from the first major surface and the second major surface. The first mask layer 120 defines a plurality of through first openings 122 arranged along the first direction and the second direction. There may be a one-to-one correspondence between the microlenses and the first openings. In some embodiments, for each first opening in at least most of the first openings 122, the first opening defines a region 123 with a void.

[0045] In some embodiments, the optical element or layer 200 is prepared by microreplicating a plurality of microlenses 102 using, for example, a casting and ultraviolet (UV) curing process, wherein a resin is cast on a substrate and cured in contact with a replication tool surface, as generally described in U.S. Pat. Nos. 5,175,030 (Lu et al.), 5,183,597 (Lu), and 9,919,339 (Johnson et al.), and U.S. Patent Application Publication No. 2012 / 0064296 (Walker, JR. et al.). An optically opaque first mask layer 120 may then be formed, for example, by coating an opaque material onto a major surface 143 of the microlens substrate opposite the first major surface 103. The opaque material may have a sufficient thickness to render the material suitably optically opaque. For example, the opaque material may have a thickness of 10 nm to 5 microns. In some embodiments, the opaque material is aluminum having a thickness of 10 nm to 500 nm (e.g., 15 nm to 150 nm, or 15 nm to 100 nm, or 20 nm to 50 nm), which can be applied using, for example, standard magnetron sputtering. The additional layer 144 can be coated or laminated onto the opaque material layer. If desired, an optional second mask layer can then be deposited on the additional layer 144. If desired, an optional second additional layer can then be disposed on a second mask layer opposite to the additional layer 144. The opening 122 can then be formed, for example, by laser ablation through the microlens 102. Suitable lasers include, for example, a fiber laser operating at a wavelength of 1070 nm, such as a 40W pulsed fiber laser. In some embodiments, layer 120 is formed by applying a reflective multilayer optical film to the major surface 143. A physical or optical through-opening can then be formed in the optical film by irradiating the microlens with a laser. Using a laser to form holes in a layer through a microlens array is generally described in, for example, US 2007 / 0258149 (Gardner et al.) Other suitable methods of forming openings include microprinting and photolithography (eg, involving using a microlens layer to expose a photolithographic mask).

[0046] In some embodiments, a method for preparing an optical layer is provided. The method may include providing a first layer including a structured first major surface 103 and an opposite second major surface 104. The structured first major surface 103 includes a plurality of microlenses 102 arranged along orthogonal first and second directions. The first layer includes an embedded optically opaque first mask layer, which is disposed between the first major surface and the second major surface and is spaced apart from the first major surface and the second major surface. The method may also include irradiating the first mask layer through the plurality of microlenses 102 to form a plurality of through first openings 122 arranged along the first direction and the second direction in the first mask layer. There may be a one-to-one correspondence between the microlenses and the first openings. In some embodiments, the first layer also includes an optically opaque second mask layer, wherein the first mask layer is disposed between the first major surface 103 and the second mask layer and is spaced apart from the first major surface and the second mask layer. The irradiation step of the first mask layer may also include irradiating the second mask layer through the plurality of microlenses 102 and through the first mask layer to form a plurality of through second openings 127 arranged along the first direction and the second direction in the second mask layer. There may be a one-to-one correspondence between the micro lenses 102 and the second openings 127 .

[0047] Figure 5A-5D is a schematic cross-sectional view of a region in an optical element or layer near an embedded optically opaque first mask layer 120 according to some embodiments. In some embodiments, for each of at least a majority of the first openings 122, the first opening defines a voided region 723 having a maximum thickness h greater than an average thickness t of the first mask layer 120. In some embodiments, the first mask layer 120 has an average thickness t, the first openings 122 have an average maximum lateral dimension d, and t / d<0.05, or t / d<0.01, or t / d<0.005. In some embodiments, for each of at least a majority of the first openings, the voided region 123 or 723 extending through the first opening is substantially laterally coextensive with the first opening. The voided region can be described as being substantially laterally coextensive with the first opening when the voided region fills at least 60% (or at least 70%, or at least 80%, or at least 90%) of the total area of ​​the first opening. Figure 5A is a schematic cross-sectional view of a portion of an optical layer including a mask layer 120 including an opening 122 and a voided region 723 laterally coextensive with the opening 122 . Figure 5B 1 is a schematic cross-sectional view of a portion of an optical layer including a mask layer 120, the mask layer including an opening 122 and a voided region 723 that is substantially laterally coextensive, but not completely laterally coextensive, with the opening 122. The voided region is an area from which solid material has been removed. Air or gas may be present in the voided region.

[0048] In some embodiments, voided region 723 has a top major surface facing first major surface 103 and an opposing bottom major surface facing second major surface 104, wherein in a cross section of the optical layer substantially perpendicular to the optical layer, the top surface and the bottom surface are closer to the center of the voided region by a separation h1 (see Figure 5C ) is greater than the spacing h2 closer to the edge of the region with the voids, where h1>h2. At least one of the top major surface and the bottom major surface may have a surface roughness R. For example, the surface roughness R may be at least 10nm, or at least 12nm, or at least 15nm, or at least 20nm. For example, the surface roughness R may not exceed 200nm, or not exceed 150nm, or not exceed 120nm. The surface roughness may be caused by laser ablation of the mask layer. For example, laser ablation of the mask layer may roughen the surface of the region 723 with the voids by depositing nanoparticles along the surface. Surface roughness refers to the average deviation of the surface from an average smooth surface.

[0049] In some embodiments, for each of at least a majority of first openings 122, the first opening defines a voided region 723 having a top major surface 171 facing first major surface 103 and an opposing bottom major surface 173 facing second major surface 104. Figure 5D , the optical layer includes a plurality of nanoparticles 177 concentrated along at least one of the top major surface 171 and the bottom major surface 173 of the voided region (e.g., in a cross section of the optical layer substantially perpendicular to the optical layer). In some embodiments, in a cross section of the optical layer substantially perpendicular to the optical layer (e.g., in Figure 5D ), the spacing between the top surface 171 and the bottom surface 173 closer to the center of the voided region is greater than the spacing closer to the edge of the voided region 723 (e.g., as shown in FIG. Figure 5A , where the spacing near the center is h and the spacing near the edge is about t, or as Figure 5C , where h1>h2). The surface roughness of at least one of the top major surface and the bottom major surface can be in the range of 10 nm to 200 nm or in the range described elsewhere.

[0050] In some embodiments, the top surface 171 and the bottom surface 173 are substantially concave toward each other (e.g., greater than 50%, or at least 60%, or at least 70% of the area along one or both of the surfaces is concave toward each other).

[0051] In some embodiments, the first mask layer 120 includes a first material, and the nanoparticles 177 include at least one of the first material or an oxide of the first material. In some embodiments, the first material is a metal. Any suitable metal can be used for the first material. For example, the metal can be aluminum, titanium, chromium, zinc, tin, tungsten, gold, silver, or an alloy thereof. In some embodiments, the nanoparticles include an oxide of the metal. For example, the nanoparticles can include aluminum oxide, titanium oxide, chromium oxide, zinc oxide, or a combination thereof. In some embodiments, the nanoparticles 177 are or include aluminum and aluminum oxide. In some embodiments, the nanoparticles 177 include aluminum oxide at greater than about 50 weight percent.

[0052] In some embodiments, at least 90% of the nanoparticles 177 have an average diameter less than about 150 nm, or less than about 100 nm. In some embodiments, at least 90% of the nanoparticles have an average diameter greater than about 1 nm, or greater than about 5 nm, or greater than about 10 nm. The average diameter of a nanoparticle is the diameter of a sphere whose volume is equal to the volume of the nanoparticle.

[0053] In some embodiments, the optical layer includes a first polymer layer disposed between the first major surface and the mask layer, and a second polymer layer disposed between the mask layer and the second major surface. In some embodiments, at least one of the first polymer layer and the second polymer layer includes a plurality of second nanoparticles uniformly dispersed therein. For example, the second nanoparticles can be included to increase the refractive index of the layer as known in the art (see, e.g., U.S. Pat. No. 8,202,573 (Pokorny et al.)).

[0054] In some embodiments, Figure 4 The optical element or layer 200 schematically shown in FIG. 1 also includes an optically opaque second mask layer 125 (see, for example, Figure 1 ), the optically opaque second mask layer defines a plurality of through second openings 127 arranged along the first direction and the second direction, wherein the first mask layer 120 is disposed between the first main surface 103 and the second mask layer 125 and is spaced apart from the first main surface and the second mask layer, wherein there can be a one-to-one correspondence between the microlenses and the second openings. In some embodiments, for each microlens, the microlens and the corresponding first opening and second opening are substantially centered on a straight line that is at the same oblique angle to the first mask layer. The first opening and / or the second opening can be as described elsewhere (see, e.g. Figure 5A-5D ).

[0055] Figure 6is a schematic cross-sectional view of an optical element or layer 200 disposed on a photosensor 225. In some embodiments, an optical system 250 includes an optical element or layer 200 and a photosensor 225 including a plurality of sensor pixels 227. In some embodiments, there is a one-to-one correspondence between microlenses 102 and sensor pixels 227, such that for each microlens in at least a majority of the microlenses 102, the microlens 102 and the corresponding first opening 122 and sensor pixel 227 are substantially centered on a line 140 that is at the same oblique angle θ with the first mask layer 120.

[0056] Figure 7 1 is a schematic top view projection of a plurality of microlenses 102 and through openings 126 (e.g., corresponding to the first through opening 122 or the second through opening 127). The microlenses 102 are arranged along orthogonal first and second directions (x and y directions), and the openings 126 are arranged along the first and second directions. In the illustrated embodiment, the microlenses 102 and the through openings 126 are located on a regular triangular array. Other patterns are also possible (e.g., square or rectangular arrays, other periodic arrays, or irregular patterns).

[0057] Figure 8 is a schematic diagram of an optical system 350 according to some embodiments. Fig. 9 is a schematic diagram of some embodiments of optical system 350.

[0058] In some embodiments, the optical system 350 includes an optical element 300 (e.g., corresponding to 100 or 200) and a refractive component 160. The optical element 300 includes a lens layer 110, which includes a plurality of microlenses arranged along orthogonal first and second directions (x and y directions); and an optically opaque first mask layer 120, which is spaced apart from the lens layer 110 and defines a plurality of through first openings arranged along the first and second directions. In some embodiments, there is a one-to-one correspondence between the microlenses and the first openings, such that for each microlens, the microlens and the corresponding first opening are substantially centered on a straight line 140, wherein each straight line is at the same oblique angle θ with the lens layer 110. In some embodiments, the refractive component 160 extends along the first and second directions and is disposed near the optical element, such that for at least one first light beam 230 incident on the refractive component along a third direction (-z direction) substantially orthogonal to the lens layer, the refractive component 160 splits the first light beam into light beams along corresponding 2 to 9 main directions 667 (see, e.g., Figure 12A-12C ) 2 to 9 beam segments 665 leaving the refractive component (see e.g. Figure 12A-12C ), wherein the first main direction 131 among 2 to 9 main directions is substantially parallel to each straight line 140.

[0059] In some embodiments, the optical element 300 further includes an optically opaque second mask layer 125 that is spaced apart from the lens layer 110 and the first mask layer 120 and defines a plurality of through second openings 127 arranged along the first direction and the second direction, wherein the first mask layer 120 is disposed between the lens layer 110 and the second mask layer 125 (see, e.g., Figure 1 In some embodiments, there is a one-to-one correspondence between microlenses and second openings, such that for each microlens 102a and corresponding straight line 140a, the microlens 102a and the corresponding first opening 122a and second opening 127a are substantially centered on the straight line 140.

[0060] In some embodiments, the optical system 350 also includes a photosensor 225 adjacent to the optical element 300 (see, e.g., Figure 6 As further described elsewhere herein, photosensor 225 may include a plurality of sensor pixels. There may be a one-to-one correspondence between microlenses and sensor pixels, such that for each microlens and corresponding straight line, the microlens and corresponding first opening and sensor pixel are substantially centered on straight line 140.

[0061] In some embodiments, for each microlens of at least a majority of the microlenses in the plurality of microlenses, at least two of the beam segments 112, 114 are incident on the microlens, wherein at least two of the beam segments 112, 114 include the first beam segment 112 propagating along the first principal direction 131. In some embodiments, at least 30%, or at least 40%, or at least 45%, or at least 50%, or at least 55% of the light in the beam segments incident on the optical element 300 along the first principal direction 131 (but not any other principal directions) is transmitted through the optical element 300. In some embodiments, for each principal direction 132 other than the first principal direction 131, no more than 10%, or no more than 5%, of the light in the beam segments incident on the optical element 300 along the principal direction is transmitted through the optical element.

[0062] In some embodiments, the optical system 350 includes a refractive component 160 extending along orthogonal first and second directions such that for at least one first light beam 230 incident on the refractive component 160 along a third direction substantially orthogonal to the first and second directions, the refractive component splits the first light beam into 2 to 9 beam segments that exit the refractive component along corresponding 2 to 9 principal directions, wherein the 2 to 9 principal directions include the first principal direction 131. In some embodiments, the 2 to 9 principal directions define an angle β therebetween, wherein each angle β is greater than about 30 degrees. In some embodiments, the refractive component 160 includes a first prism film 252 including a first plurality of prisms 254 extending along a first longitudinal direction (x direction) substantially parallel to the lens layer 110. In some embodiments, the refractive component 160 also includes a second prism film 256 adjacent to the first prism film 252. The second prism film 256 may include a second plurality of prisms 258 extending along a second longitudinal direction (y direction) substantially parallel to the lens layer 110 and substantially orthogonal to the first longitudinal direction.

[0063] The optical system 350 may also include an optical element 300 disposed near the refractive component 160 so that at least 45% (or any of the ranges described elsewhere herein) of the light in the beam segment incident on the optical element 300 along the first principal direction 131 (but not any other principal direction 132) is transmitted through the optical element 300. The optical system 350 may also include a light source 139 and / or 141, which is configured to emit light 142 and / or 147, respectively, in a direction substantially parallel to a second principal direction of the 2 to 9 principal directions. In some embodiments, the light source is an infrared light source. In some embodiments, the optical system 350 includes an infrared diffuser. For example, the infrared diffuser may be positioned between the infrared light source and the touch surface of the display to improve the uniformity of the infrared light incident on the touch surface. The optical system 350 may also include an optical sensor 145, which is configured to receive light transmitted through the optical element 300 along the first principal direction 131. In some embodiments, the optical sensor 145 is an infrared light sensor. In some embodiments, the first main direction and the second main direction are different (e.g., the first main direction can be direction 131, and the second main direction can be direction 132). In some embodiments, the first main direction and the second main direction are the same (e.g., the first main direction and the second main direction can each be direction 131).

[0064] Figure 10A-10B is a schematic diagram of the maximum projected area of ​​the optical element 300 and the refractive component 160 according to some embodiments. Fig. 10ASchematically illustrated, in some embodiments, optical element 300 is substantially coextensive with at least a portion of refractive component 160, wherein the maximum projected area of ​​the portion of refractive component 160 is at least about 30% of the maximum projected area of ​​refractive component 160. Fig. 10B Schematically shown in FIG. 1 , in some embodiments, optical element 300 and refractive component 160 are substantially coextensive. A layer or surface can be substantially coextensive with another layer or surface when at least 60%, or at least 70%, or at least 80%, or at least 90% of the total area of ​​the layer or surface is coextensive with at least 60%, or at least 70%, or at least 80%, or at least 90% of the total area of ​​the other layer or surface.

[0065] The number of principal directions may be determined, for example, by the number and shape of light redirecting films included in the refractive component 160. For example, at least one first light beam incident on a single prismatic film (e.g., a substantially perpendicularly incident light beam having a diameter greater than the prism width) will result in two principal directions, while a first light beam incident on crossed prismatic films will result in four principal directions. Fig.11 3 is a schematic cross-sectional view of a truncated prismatic film 352, which includes a plurality of truncated prisms 354 arranged along a first direction (x direction) and extending along an orthogonal second direction (y direction). At least one first light beam incident on the film 352 will be divided into 3 beam segments, each beam segment corresponding to a small face of the truncated prism 354. More generally, n non-vertical small faces can result in n beam segments. Two crossed truncated prismatic films 352 will result in 9 main directions. In some embodiments, 2 to 9 main directions are 2, 4 or 9 main directions. In some embodiments, 2 to 9 main directions are 4 main directions.

[0066] Figure 12A-12C 667. Each point in the conoscopic diagram represents a direction (specified by an azimuth and a polar angle). Darker areas indicate higher intensity transmitted light. The beam segment 665 is a higher intensity region representing a beam that propagates primarily along the main direction 667, which can be considered the direction in which the intensity has a local maximum. Fig. 12A In FIG. 12 a, there are two beam segments 665, which propagate in two main directions 667; in FIG. 12 b, there are four beam segments 665, which propagate in four main directions 667; and Fig. 12C In , there are nine beam segments 665 , which propagate in nine main directions 667 .

[0067] In some embodiments, the microlens layer is bonded to the display panel via a low refractive index layer. In some embodiments, the low refractive index layer has a refractive index of no more than 1.3 (e.g., in the range of 1.1 to 1.3), and is disposed on the first major surface 103 of the lens layer 110 and has a major surface that is substantially conformal to the first major surface. Unless otherwise specified, the refractive index refers to the refractive index at 633 nm. The layer having a refractive index of no more than 1.3 can be, for example, a nanovoided layer as described in U.S. Patent Application Publication Nos. 2013 / 0011608 (Wolk et al.) and Nos. 2013 / 0235614 (Wolk et al.).

[0068] In some embodiments, optical decoupling structures (also referred to as elongated spacer elements) are disposed on the first major surface 103 such that the optical decoupling structures can be bonded to an adjacent display panel with an adhesive layer, for example, while creating an air gap between the microlenses and the adhesive layer.

[0069] Fig.13A is a schematic cross-sectional view of an optical element 1300a (e.g., corresponding to 100, 200, or 300) that includes a layer 1360a having opposing first and second major surfaces 1362 and 1364a. The first major surface 1362 includes an array of microlenses 1350 and an array of optical decoupling structures 1355 extending from the layer 1360a to above the tops of the microlenses 1350. For example, the optical decoupling structures 1355 can be pillars. Each microlens in the microlens array 1350 is recessed toward the second major surface 1364a. Each optical decoupling structure 1357 of at least a majority of the optical decoupling structures in the array of optical decoupling structures 1355 is positioned between two or more adjacent microlenses 1351 and 1352 in the microlens array 1350 and is arranged in a direction away from the second major surface 1364a (e.g., the z direction, see Fig.13A The xyz coordinate system shown in FIG. 1 extends over two or more adjacent microlenses 1351 and 1352. For example, all optical decoupling structures in the array of optical decoupling structures 1355 may be positioned between two or more adjacent microlenses in the array of microlenses 1350, or all optical decoupling structures except for optical decoupling structures near corners or edges of the array of microlenses 1350 may be positioned between two or more adjacent microlenses.

[0070] In some embodiments, layer 1360a is an integral layer (e.g., formed together with microlenses 1350 during, for example, a casting and curing process). In other embodiments, optical decoupling structures 1355 are printed onto the microlens layer such that the optical decoupling structure layer and the microlens layer are sublayers of layer 1360a.

[0071] In some embodiments, the array of optical decoupling structures 1355 is adapted to substantially scatter, diffuse, reflect, or absorb light obliquely incident on the optical element 1300a. This can be achieved, for example, by adding diffusing particles to the printed optical decoupling structures, or by appropriately selecting the shape of the optical decoupling structures (e.g., the curvature of the sides), or by applying a coating (e.g., a reflective coating) to the optical decoupling structures. This can provide reduced crosstalk between adjacent microlenses. For example, obliquely incident light 1303 can be transmitted through the optical decoupling structures and through a first microlens to a mask layer aligned with an adjacent microlens (see, e.g., Fig. 13B ) in the array of optical decoupling structures 1355. Such crosstalk can be significantly reduced if the optical decoupling structures substantially scatter, diffuse, reflect or absorb obliquely incident light. This schematically illustrates that light 1308 is diffused by the optical decoupling structures in the array of optical decoupling structures 1355, thereby reducing potential crosstalk.

[0072] The optical decoupling structure can be any object that protrudes beyond the microlens to attach to the adjacent layer so that the adjacent layer does not contact the microlens. The optical decoupling structure can be a cylindrical column, or it can be a column with a non-circular cross-section (e.g., a rectangular, square, elliptical, or triangular cross-section). The optical decoupling structure may have a constant cross-section, or the cross-section may vary along the thickness direction (e.g., the optical decoupling structure may be a column that tapers to become thinner near the top of the column). In some embodiments, the optical decoupling structure has a tapered elliptical cross-section. For example, the optical decoupling structure may have any of the geometric shapes of the optical decoupling structures described in International Application Publication No. WO 2019 / 135190 (Pham et al.). In some embodiments, the optical decoupling structure extends from the base of the microlens array. In some embodiments, at least some of the optical decoupling structures are disposed on top of at least some of the microlenses.

[0073] Fig. 13B 1360b. The optical element 1300b includes the optical element 1300a and further includes a layer 1360b. The layers 1360a and 1360b together define a first layer having a first major surface 1362 and an opposite second major surface 1364b. The optical element 1300b also includes a mask layer 1388 disposed on the second major surface 1364b. The mask layer 1388 is also indirectly disposed on the second major surface 1364a. The additional layer 1374 is disposed on the mask layer 1388. If desired, an optional second mask layer can be disposed on the additional layer 1374 opposite to the mask layer 1388.

[0074] Masking layer 1388 includes an array of through openings 1380, as further described elsewhere herein. Optical element 1300b also includes an adhesive layer 1343 adjacent to first major surface 1362. Each optical decoupling structure 1355 at least partially penetrates adhesive layer 1343, and each microlens 1350 is completely separated from adhesive layer 1343 by an air gap 1344. In the illustrated embodiment, adhesive layer 1343 is attached to display 1390.

[0075] In some embodiments, the optical element or layer includes two pluralities of microlenses. Fig.14 1 is a schematic cross-sectional view of an optical element or layer 400 (e.g., corresponding to 100, 200, or 300) having opposing first and second major surfaces 103, 104, wherein the first major surface 103 includes a first plurality of microlenses 102, and the second major surface 104 includes a second plurality of microlenses 202. The optical element or layer 400 includes an embedded optically opaque first mask layer 120 disposed between and spaced apart from the first and second major surfaces 103, 104. The first mask layer 120 defines a plurality of first openings 122 therethrough. The microlenses 102 and 202 can be formed on opposite sides of the mask layer 120 (e.g., embedded between polymer layers) using a casting and curing process, for example, wherein the microlenses 102 and 202 are aligned, and after forming the microlenses 102 and 202, the first openings 122 can be formed in the mask layer 120.

[0076] In some embodiments, there is a one-to-one correspondence between microlenses 102 and first openings 122. In some embodiments, microlenses 102 and corresponding first openings 122 are substantially centered on a line 140 that is at the same oblique angle θ with lens layer 110 or with first mask layer 120. In some embodiments, there is a one-to-one correspondence between at least most of microlenses 102 and at least most of microlenses 202. In some embodiments, there is a one-to-one correspondence between microlenses 102 and microlenses 202. In some embodiments, microlenses 102 and corresponding first openings 122 and corresponding microlenses 202 are substantially centered on line 140. In some embodiments, for each of at least most of the first openings 122, the first opening defines a voided region 123. As further described elsewhere, the voided region can have a maximum thickness greater than an average thickness of the first mask layer 120. For example, microlenses 102 can be used to focus light on openings 122, and microlenses 202 can be used to collimate light transmitted through openings 122. In some embodiments, the optical element or layer 400 includes two spaced-apart mask layers disposed between the first major surface 103 and the second major surface 104 (see, e.g., Figure 1 ).

[0077] Example

[0078] Examples 1-2 and Comparative Example C1

[0079] Optical modeling using LightTools ray tracing software (available from Synopsis, Inc., Mountain View, CA) was performed as follows. A Lambertian point source was used to represent the fingerprint. In the model, a crossed prismatic film was placed between the point source and the image sensor, an LCD display panel was placed between the point source and the crossed prismatic film, and an optical element similar to optical element or layer 100 or 200 was placed between the crossed prismatic film and the image sensor, with the microlenses facing the crossed prismatic film and the mask layer facing the image sensor. The through openings were positioned so that light incident on the microlenses at 52 degrees relative to the normal to the plane of the optical element would pass through the optical element. The model parameters are as follows: the LCD panel thickness is 0.5 mm; the distance from the point source to the optical element is 1 mm; the radius of curvature of the microlens is 25 microns; the distance from the top of the microlens layer to the first mask layer is 32 microns; when two mask layers are included, the spacing between the two mask layers is 5 microns; the through opening diameter is 3 microns; the refractive index of the microlens is 1.65; and the material of the mask layer is modeled as a perfect optical absorber.

[0080] Figure 15-17 Point spread functions determined for the case where the optical element includes two mask layers (Example 1), for the case where the optical element includes only one mask layer (Example 2), and for the case where the optical element is omitted (Comparative Example C1) are shown respectively. When the optical element is included, the width of the point spread function is significantly reduced compared to the case where the optical element is omitted. Including two mask layers significantly reduces the point spread function compared to the case where a single mask layer is used.

[0081] Example 3

[0082] An optical element similar to optical element 100 is prepared as follows. A microlens layer is formed on a 0.92 mil thick PET substrate using a casting and curing process. The microlens layer is formed of an acrylic resin having a refractive index of about 1.69 at 532 nm. The average radius of curvature of the microlenses is about 17 microns and is arranged at a pitch of about 20 microns. A 30 nm thick aluminum layer is vacuum coated onto the PET substrate on the side substrate opposite the microlens layer, a 4 micron thick polymer layer is coated onto the aluminum layer and cured, a second 30 nm thick aluminum layer is vacuum coated onto the polymer layer, and a 1 micron thick polymer layer is coated onto the second aluminum layer and cured. Vias are then formed in the aluminum layer by laser ablation through the microlens layer. A 40 W SPI laser (SPI Lasers, Southampton, UK) was used at 50% power, 7x expander installed, 167 mm F-theta lens, 30 nm pulse length, 20 kHz repetition rate, 2 m / s scan speed, and 100 micron spacing.

[0083] Approximately 120 nm thick segments of the resulting optical layer were microdissected from the sample. Fig.18 is a transmission electron microscope (TEM) image of a cross section through an opening in the first mask layer 120, which is an embedded layer of the optical element 100. Voided regions 723 or air traps resulting from the ablation process are visible in the image. Cracks in the mask layers 120 and 125 resulting from the microdissection process are visible. Voided regions are formed in the mask layer 125 outside the region shown in the figure. The maximum thickness of the voided regions 723 is greater than the thickness of the first mask layer. Fig.19 φ is a high angle annular dark field (HAADF) image of a cross section through the opening in the first mask layer 120 . Fig. 20 for Fig.19 Higher magnification image of a portion of. Nanoparticles are visible at the opposite surface of the voided area. STEM-EDS (Scanning Transmission Electron Microscopy - Energy Dispersive Spectroscopy) analysis shows that the nanoparticles are mainly composed of aluminum and oxygen.

[0084] Terms such as "about" will be understood by one of ordinary skill in the art in the context of use and description in this specification. If it is not clear to one of ordinary skill in the art in the context of use and description in this specification that "about" should be used to express the amount of feature size, quantity, and physical properties, then "about" will be understood to mean within 10% of the specified value. A quantity given as about a specified value may be exactly the specified value. For example, if it is not clear to one of ordinary skill in the art in the context of use and description 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 the value may be 1.

[0085] All references, patents, and patent applications cited above are hereby incorporated by reference in their entirety in a consistent manner. In the event of inconsistencies or conflicts between an incorporated reference portion and the present application, the information in the foregoing description shall prevail.

[0086] Unless otherwise indicated, the description of the elements in the drawings should be understood to apply equally to the corresponding elements in the other drawings. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that the specific embodiments shown and described may be replaced with a variety of alternative and / or equivalent implementations without departing from the scope of the present disclosure. The present application is intended to cover any modification or variation of the specific embodiments discussed herein. Therefore, the present disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. An optical layer, the optical layer include: a structured first major surface and an opposing second major surface, the structured first major surface comprising a plurality of microlenses arranged along orthogonal first and second directions; and an embedded optically opaque first mask layer disposed between and spaced apart from the first major surface and the second major surface, the first mask layer defining therein a plurality of laser-ablated through-going first openings arranged along the first direction and the second direction, a one-to-one correspondence between the microlenses and the first openings, wherein for each of at least a majority of the first openings, the first opening defines a region having a void, the voided region having a top major surface facing the first major surface and an opposing bottom major surface facing the second major surface, wherein in a cross-section of the optical layer substantially perpendicular to the optical layer, the top major surface and the bottom major surface are separated more near a center of the voided region than near an edge of the voided region; The average thickness of the first mask layer is t, the first opening has an average maximum lateral dimension d, and t / d<0.

05.

2. The optical layer according to claim 1, in, The voided region has a maximum thickness greater than the average thickness of the first mask layer.

3. The optical layer according to claim 1, wherein wherein in a cross-section of the optical layer substantially perpendicular to the optical layer, the optical layer comprises a plurality of nanoparticles concentrated along at least one of the top major surface and the bottom major surface of the voided region. 4 . The optical layer of claim 3 , wherein the first mask layer comprises a first material, and the nanoparticles comprise at least one of the first material or an oxide of the first material.

5. The optical layer according to claim 1, in, At least one of the top major surface and the bottom major surface has a surface roughness in a range of 10 nm to 200 nm.

6. An optical system, the optical system include: The optical layer according to any one of claims 1 to 5; an optically opaque second mask layer, the optically opaque second mask layer being spaced apart from the lens layer and the first mask layer and defining a plurality of penetrating second openings arranged along the first direction and the second direction therein, the first mask layer being disposed between the lens layer and the second mask layer, and there being a one-to-one correspondence between the microlenses and the first openings and the second openings, so that for each microlens, the microlens and the corresponding first opening and second opening are substantially centered on a straight line having the same oblique angle as the lens layer, wherein when image light carrying an image is incident on the microlens along the straight line, the image light substantially fills the microlens, more than 45% of the incident image light is transmitted by the second opening, and at least one of the first opening and the second opening is sized so as to reduce image quality degradation caused by the microlens. The optical system of claim 6 , wherein the first opening is a physical opening.

8. The optical system of claim 6, wherein the first opening is an optical opening.

9. The optical system according to claim 6, further comprising: include: a liquid crystal display extending along the first direction and the second direction; a light guide configured to illuminate the liquid crystal display; a refractive component disposed between the liquid crystal display and the light guide, the refractive component comprising a first prismatic film, the first prismatic film comprising a first plurality of prisms extending along a first longitudinal direction substantially parallel to the lens layer; and an optical sensor disposed near the light guide and opposite to the liquid crystal display, An optical element including the lens layer and the first and second mask layers is disposed between the light guide and the optical sensor such that the second mask layer faces the optical sensor.

10. The optical system of claim 9, wherein the refractive component further comprises a second prism film adjacent to the first prism film, the second prism film comprising a second plurality of prisms extending along a second longitudinal direction substantially parallel to the lens layer and substantially orthogonal to the first longitudinal direction.

11. An optical system, the optical system include: An optical element comprising an optical layer according to any one of claims 1 to 5, wherein, for each microlens, the microlens and the corresponding first opening are substantially centered on a straight line, each straight line having a same oblique angle with the lens layer; and a refractive component extending along the first direction and the second direction and disposed near the optical element such that, for at least one first light beam incident on the refractive component along a third direction substantially orthogonal to the lens layer, the refractive component splits the first light beam into 2 to 9 beam segments exiting the refractive component along corresponding 2 to 9 main directions, a first main direction of the 2 to 9 main directions being substantially parallel to each straight line.

12. The optical system of claim 11 , wherein the optical element further comprises an optically opaque second mask layer, the optically opaque second mask layer being spaced apart from the lens layer and the first mask layer and defining therein a plurality of penetrating second openings arranged along the first direction and the second direction, the first mask layer being disposed between the lens layer and the second mask layer, and there being a one-to-one correspondence between the microlenses and the second openings, such that for each microlens and the corresponding straight line, the microlens and the corresponding first opening and second opening are substantially centered on the straight line.

13. The optical system according to claim 11 further includes a photosensor, which is adjacent to the optical element and includes a plurality of sensor pixels, and there is a one-to-one correspondence between the microlenses and the sensor pixels, so that for each microlens and the corresponding straight line, the microlens and the corresponding first opening and the sensor pixel are substantially centered on the straight line.

14. The optical system according to claim 11, further comprising an infrared light source arranged to emit light toward the refractive component in a direction substantially parallel to a second principal direction among the 2 to 9 principal directions.

15. An optical system, the optical system include: a refractive component extending along orthogonal first and second directions such that, for at least one first light beam incident on the refractive component along a third direction substantially orthogonal to the first and second directions, the refractive component splits the first light beam into 2 to 9 beam segments exiting the refractive component along respective 2 to 9 principal directions, the 2 to 9 principal directions including a first principal direction; an optical element disposed adjacent to the refractive component such that at least 45% of the light in the beam segment incident on the optical element along the first principal direction, but not in any other principal direction, is transmitted through the optical element, wherein the optical element comprises an optical layer according to any one of claims 1 to 5; a light source arranged to emit light in a direction substantially parallel to a second main direction of the 2 to 9 main directions; and An optical sensor is arranged to receive light transmitted through the optical element along the first principal direction.

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