Substrateless structured optical film, and optical stack and display including same

Abstract

An optical stack includes a substrateless radiation-cured optical film having opposing first and second major surfaces; and a first layer disposed directly on, and substantially coextensive with, the first major surface of the optical film. The optical film includes a plurality of alternating optically transmissive and absorptive regions disposed between the first and second major surfaces of the optical film; and a first land region integral with a first plurality of the optically transmissive regions. The optically transmissive regions have an average height H from the first land region to the second major surface along a thickness direction of the optical film and an average width W in a first in-plane direction of the optical film orthogonal to the thickness direction. H / W is greater than about 1. A display includes the optical film.

Description

[0001] SUBSTRATELESS STRUCTURED OPTICAL FILM, AND OPTICAL STACK AND DISPLAY INCLUDING SAME

[0002] TECHNICAL FIELD

[0003] The present description relates generally to structured optical films.

[0004] BACKGROUND

[0005] A structured layer of an optical film can be made by casting and curing a resin in contact with a structured tool surface and a substrate.

[0006] SUMMARY

[0007] In some aspects, the present description provides an optical stack including a substrateless radiation-cured optical film having opposing first and second major surfaces; and a first layer disposed directly on, and substantially coextensive with, the first major surface of the optical film. The first layer can be a release liner that can be removed from the optical film, or the first layer can be an adhesive layer fixedly attached to the optical film. The optical film can be a light control film and / or can be incorporated into a display.

[0008] In some aspects, the present description provides an optical stack including a substrateless radiation-cured light control film having opposing first and second major surfaces; and a first layer disposed directly on, and substantially coextensive with the first major surface of the light control film. The first layer can be releasably attached to the first major surface, or the first layer can be a roomtemperature adhesive layer fixedly attached to the first major surface. The light control film includes a plurality of alternating optically transmissive and absorptive regions disposed between the first and second major surfaces of the light control film; and a first land region integral with a first plurality of the optically transmissive regions. The first land region includes the first major surface and extends from the first major surface to the optically absorptive regions. The first land region can have an average thickness in a range of about 0.05 to 200 micrometers. The optically transmissive regions have an average height H from the first land region to the second major surface along a thickness direction of the light control film and an average width W in a first in-plane direction of the light control film orthogonal to the thickness direction. H / W can be greater than about 1.

[0009] In some aspects, the present description provides an optical film including a first monolithic radiation-cured layer having a structured first major surface and an opposite second major surface. The structured first major surface has a plurality of structures having an average height H in a thickness direction of the optical film and an average width W in a first in-plane direction of the optical film orthogonal to the thickness direction. H / W can be greater than about 1. The optical film includes a second monolithic radiation-cured layer having a structured first major surface and an opposite second major surface. The structured first major surfaces of the first and second radiation-cured layers are disposed on, and substantially conform to, one another. For each of the first and second radiation-cured layers, the second major surface is not fixedly attached to any other layer or is directly fixedly attached to a roomtemperature adhesive layer substantially coextensive with the second major surface.

[0010] In some aspects, the present description provides a display including an emissive layer; a substrateless radiation-cured light control film having opposing first and second major surfaces with the second major surface facing the emissive layer; and an adhesive layer disposed between the second major surface and the emissive layer and having an average thickness greater than about 15 micrometers. The light control film includes a plurality of alternating optically transmissive and absorptive regions disposed between the first and second major surfaces of the light control film; and a first land region integral with a first plurality of the optically transmissive regions. The first land region includes the first major surface and extends from the first major surface to the optically absorptive regions. The first land region can have an average thickness in a range of about 0.05 micrometers to about 200 micrometers. The optically transmissive regions have an average height Ht from the first land region to the second major surface along a thickness direction of the light control film and an average width W in a first in-plane direction of the light control film orthogonal to the thickness direction. Ht / W can be greater than about 1. An average minimum distance between the optically absorptive regions and the emissive layer is less than about 35 micrometers. The first major surface is attached to a room-temperature adhesive layer having an average thickness greater than about 15 micrometers and being substantially coextensive with the first major surface. An average distance between the first major surface and the room-temperature adhesive layer is less than about 10 micrometers.

[0011] In some aspects, the present description provides a display including an emissive layer; a substrateless radiation-cured light control film having opposing first and second major surfaces, where the second major surface faces the emissive layer; a first adhesive layer disposed between the second major surface and the emissive layer; a cover glass; and a second adhesive layer disposed between the cover glass and the first major surface, where the second adhesive layer is disposed directly on the first major surface. The cover glass, the light control film, the first and second adhesive layers, and the emissive layer can be substantially coextensive with one another. Each of the first and second adhesive layers can be a room-temperature adhesive layer. The light control film can include a plurality of alternating optically transmissive and absorptive regions disposed between the first and second major surfaces of the light control film; and a first land region integral with a first plurality of the optically transmissive regions, where the first land region includes the first major surface 151 and extends from the first major surface to the optically absorptive regions. The first land region can have an average thickness in a range of about 0.05 to 200 micrometers. The optically transmissive regions have an average height Ht from the first land region to the second major surface along a thickness direction of the light control film and an average width W in a first in-plane direction of the light control film orthogonal to the thickness direction. Ht / W can be greater than about 1.

[0012] In some aspects, the present description provides an optical film including a first monolithic radiation-cured layer having a structured first major surface and an opposite second major surface. The structured first major surface includes a plurality of structures having an average height H in a thickness direction of the optical film and an average width W in an in-plane direction of the optical film. H / W can be greater than about 1. The second major surface of the first monolithic radiation-cured layer comprises about 0.3 to 3 atomic percent Si.

[0013] In some aspects, the present description provides an optical stack including a substrateless radiation-cured optical film including opposing first and second major surfaces and defining a structured interface therein; and first and second release liners disposed directly on, and substantially coextensive with, the respective first and second major surfaces. For each of the first and second release liners, the release liner has a 180 degree peel force from the corresponding major surface of the optical film that is in a range of about 2 g / in to about 600 g / in. A difference between the 180 degree peel forces of the first and second release liners is at least about 20 g / in.

[0014] In some aspects, the present description provides an optical stack including a substrateless radiation-cured optical film including opposing first and second major surfaces and defining a structured interface therein; and a first release liner disposed directly on, and substantially coextensive with, the first major surface. The first release liner has a first 180 degree peel force from the first major surface of the optical film that is in a range of about 30 g / in to about 600 g / in.

[0015] These and other aspects will be apparent from the following detailed description. In no event, however, should this brief summary be construed to limit the claimable subject matter.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a schematic cross-sectional view of a layer of an optical film, according so some embodiments.

[0018] FIG. 2 is a schematic cross-sectional view of an optical film including optically absorptive regions disposed on a structured major surface of a layer of the optical film, according to some embodiments.

[0019] FIGS. 3-4 are schematic cross-sectional views of optical films and stacks, according to some embodiments.

[0020] FIG. 5 is a schematic illustration of a peel force measurement, according to some embodiments.

[0021] FIG. 6-7 are schematic cross-sectional views of displays, according to some embodiments.

[0022] FIG. 8 is a schematic cross-sectional view of a comparative display that may be equivalent to the display of FIG. 7 except that the comparative display includes an additional substrate between a cover glass and an emissive layer of the display.

[0023] DETAILED DESCRIPTION

[0024] In the following description, reference is made to the accompanying drawings that form a part hereof and in which various embodiments are shown by way of illustration. The drawings are not necessarily to scale. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present description. The following detailed description, therefore, is not to be taken in a limiting sense.

[0025] As is known in the art, a structured layer of an optical fdm may be fabricated via microreplication from a tool by casting and curing a polymerizable resin composition in contact with a structured surface of the tool and with a substrate. Such cast and cure methods are generally described in U.S. Pat. Nos. 5,175,030 (Lu et al.) and 5,183,597 (Lu) and in U.S. Pat. Appl. Pub. No. 2012 / 0064296 (Walker, JR. et al.), for example. In such conventional cast and cure methods, the resulting structured layer is fixedly attached to the substrate which is thick enough to be self-supporting in conventional cast and cure processes. Light control films, for example, often include such a structured layer as described in U.S. Pat. Nos. 8,012,567 (Gaides et al.); 8,213,082 (Gaides et al.); 9,791,709 (Ouderkirk et al.); and 11,550,183 (Schmidt et al.) and in U.S. Pat. Appl. Pub. Nos. 2022 / 0019007 (Schmidt et al.); 2020 / 0341173 (Schmidt et al.); 2020 / 0400865 (Schmidt et al.); and 2023 / 0028958 (Liu et al.), for example.

[0026] In some cases, it is desired to provide an optical film having a structured layer without the substrate. This can be due to the substrate adding undesirable thickness to the optical film and / or due to undesirable optical effects of the substrate (e.g., undesired reflection from an interface with the substrate or undesired effects of any birefringence of the substrate) and / or due to undesirable physical properties of the substrate (e.g., some polymeric substrates can off-gas which forms bubbles and / or pockets when the optical film is laminated to an optically clear adhesive). However, conventional cast and cure processes result in the structured layer being fixedly attached to the substrate since the structured layer is cured in contact with the substrate and bonds to the substrate so that the structures of structured layer can be removed from the tool. Attempting to cast and cure a structured layer on a conventional release liner used as a substrate results in the structured layer not properly being released from the tool upon curing. This is particularly problematic for structures having a large aspect ratio (e.g., a height to width ratio greater than about 1 or 1.2 or 1.6 or 2 or in a range described elsewhere herein). However, it has been found, according to some embodiments, that a structured layer can be formed on a substrate such that the resulting structured layer has a peel resistance from the substrate substantially greater (e.g., at least about 30 g / in) than from conventional release liners but still sufficiently low (e.g., no more than about 600 g / in) that the structured layer can be peeled from the substrate without significant damage to the structured layer or the substrate. After forming the structured layer on the substrate, additional layer(s) can be added on the structured layer. The substrate can be removed and replaced with a different substrate (e.g., a premask providing a lower peel force of the structured layer from the substrate) or attached to another layer or component via an adhesive layer, for example.

[0027] In some cases, after the structured layer is formed on a first substrate, a resin coated onto a second substrate is applied to the structured layer with the resin facing the structures so that the resin substantially fills spaces between the structures and substantially planarizes the structured layer, and then the resin is cured in contact with the structured layer and with the second substrate. Conventionally, the second substrate would have been fixedly attached to the cured resin layer. However, it has been found, according to some embodiments, that the bonding of the resin to the second substrate can be selected such that the second substrate is releasably attached to the cured backfill resin with sufficient peel strength that the second substrate remains in place during processing of the film and can then be subsequently removed upon deliberately applying a suitable peel force.

[0028] In some embodiments, the optical film is a light control film that controls transmission versus viewing angle of light transmitted through the film. Such optical films are useful in display applications, for example, as described further elsewhere herein.

[0029] FIG. 1 is a schematic cross-sectional view of a layer 101 (e.g., a monolithic radiation-cured layer) of an optical film (e.g., a light control film), according so some embodiments. The layer 101 has a structured first major surface 141 and an opposite second major surface 142. The structured first major surface 141 includes a plurality of structures 143 having an average height H in a thickness direction (z- direction) of the optical film and an average width W in a first in-plane direction (x-direction) of the optical film orthogonal to the thickness direction. In some embodiments, H / W is greater than (or at least) about 1, 1.1, 1.2, 1.4, 1.6, 1.8, 2, 2.5, or 3. H / W may be up to about 50, 40, 30, 20, 10, 8, 6, or 5, for example. For example, in some embodiments, H / W is in a range of about 1 to about 50, or about 1.2 to about 40, or about 1.4 to about 30, or about 1.6 to about 20, or about 1.8 to about 10. The structures 143 can extend (e.g., substantially along an entire length or width of the layer) along a second in-plane direction (y-direction) orthogonal to the first in-plane and thickness directions. In-plane directions generally refer to directions in the plane of a layer or film which can be defined by the directions along which the layer or film primarily extend, and which can be understood to be a tangent plane in the case of a curved layer of film. The layer 101 includes a land region 135 integral with the structures 143 where the land region 135 comprises the second major surface 142 and extends from the second major surface 142 to the structures 143. The land region has an average thickness L. In some embodiments, the average thickness L is no more than about 200, 175, 150, 125, 100, 80, 60, 40, 30, 20, 10, 5, 2, or 1 micrometers. In some such embodiments, or in other embodiments, the average thickness L is at least about 0.05, 0.06, 0.08, 0.1, 0.15, 0.2, 0.3, 0.4, 0.6, 0.8, 1, 1.5, 2, 3, 5, 10, 20, 30, 40, or 50 micrometers. For example, in some embodiments, the average thickness L is in a range of about 0.05 micrometers to about 200 micrometers, or about 0.06 micrometers to about 175 micrometers, or about 0.08 micrometers to about 150 micrometers, or about 0.1 micrometers to about 125 micrometers, or about 0.4 micrometers to about 100 micrometers, or about 0.6 micrometers to about 80 micrometers, or about 0.8 micrometers to about 60 micrometers, or about 1 micrometer to about 40 micrometers. In some cases, a thinner land (e.g., no more than about 30, 20, 10, 5, 2, or 1 micrometer) is desired to reduce the overall thickness of the film. In other cases, a thicker land (e.g., at least about 40 or 50 micrometers) is desired for improved replication fidelity with high aspect ratio (e.g., H / W greater than about 2) structures. In some embodiments, the sum of the height H and the land thickness L is Ht and Ht / W is in any of the ranges described for H / W. For example, in some embodiments, Ht / W is in a range of about 1 to about 50, or about 1.2 to about 40, or about 1.4 to about 30, or about 1.6 to about 20, or about 1.8 to about 10.

[0030] The layer 101 can be made in a cast and cure process as described further elsewhere. In some embodiments, the layer 101 is made on a substrate 110 (see, e.g., FIGS. 2-4) such that the substrate is releasably attached to the layer 101. It has been found that a peel strength of the substrate 110 from the layer 101 can be suitably high (e.g., at least about 30 g / in) that the structures 143 can be formed from a cast and cure process even when the structures have a high aspect ratio (e.g., H / W greater than about 1 or 1.2 or 1.6 or 2) and still be low (e.g., no more than about 600 g / in) enough for the substrate to be removed from the layer 101 without significant damage to the layer 101. A light control film, for example, can be made using the layer 101 as described further elsewhere herein.

[0031] FIG. 2 is a schematic cross-sectional view of an optical film (or optical stack) 201 including a plurality of optically absorptive regions 120 disposed on a structured major surface 141 of a layer 101 of the optical film 201, according to some embodiments. The optical film 201 may be described as including optical film 211 (e.g., a substrateless light control film) disposed on layer 110. The optical film 201 can be made by substantially conformally (e.g., nominally conformal or conformal up to variations small compared to the width W of the structures 141) coating optically absorptive material (e.g., via layer-by- layer deposition) onto the structured first major surface 141 and then removing (e.g., via reactive ion etching) the optically absorptive material from the horizonal (in the plane of the film) surfaces leaving optically absorptive regions on the vertical (thickness or z-direction) surfaces. Such processes and materials are described in U.S. Pat. No. 11,550,183 (Schmidt et al.) and in U.S. Pat. Appl. Pub. Nos. 2022 / 0019007 (Schmidt et al.); 2020 / 0341173 (Schmidt et al.); 2020 / 0400865 (Schmidt et al.); and 2023 / 0028958 (Uiu et al.), for example, and can result in optically absorptive regions having a high aspect ratio. The optically absorptive regions 120 can have an average height Hl in the thickness direction and an average width W1 in the first in-plane direction. In some embodiments, Hl / Wl is greater than about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100. Hl / WI can be up to about 10000, 9000, 8000, 7000, 6000, 5000, 4000, 3000, 2000, 15000, or 1000, for example. The height Hl can be equal to or about equal to H. Optionally, a second layer (see, e.g., layer 102 schematically illustrated in FIG. 3) can be disposed over the first major surface 141 and the optically absorptive material. The first layer 110 can be releasably attached to the major surface 142, or the first layer 110 can be a room-temperature adhesive layer fixedly attached to the major surface 142.

[0032] As used herein, a “room-temperature adhesive” is an adhesive adapted to form a bond to a nonadhesive layer at room temperature (about 23 deg. C). A room -temperature adhesive can be a pressure sensitive adhesive and / or an optically clear adhesive, for example. A light (e.g., ultraviolet light) cured adhesive is a room-temperature adhesive when elevated temperature is not needed for the adhesive to cure and form a bond to an adjacent layer. A hot-melt adhesive that needs an elevated temperature to achieve bonding is not a room-temperature adhesive. A thermoplastic polymer layer bonded to adjacent thermoplastic polymer layers as a result of the layers being coextruded at an elevated temperature is not a room-temperature adhesive. A primer that facilitates bonding to an adhesive layer but not to a nonadhesive layer at room temperature is not a room-temperature adhesive. Useful room-temperature adhesives include, for example, optically clear adhesives available from 3M Company (St. Paul, MN) or Norland Products (Jamesburg, NJ).

[0033] FIG. 3 is a schematic cross-sectional view of an optical fdm (or optical stack) 202, according to some embodiments. The optical fdm 202 can be made from the optical fdm 201 by depositing (backfdling) the layer 102 over the layer 101. Each of the layers 101 and 102 can be radiation-cured layers. The optical fdm or stack 202 can be described as including an optical fdm 212 (e.g., a substrateless light control fdm) and additional layers. An optional layer 112 (e.g., release liner) can be added to the layer 102 (on major surface 152 of the optical fdm 212) on the opposite side of layer 101. Optionally, an adhesive layer (e.g., corresponding to adhesive layer 115 schematically illustrated in FIG. 4) can be disposed on major surface 152 between layer 102 and the layer 112. In some embodiments, the layer 112 and the resin (e.g., backfdl resin) that forms layer 102 are applied over the layer 101 in a same step and then the resin is cured. The layer 112 may be releasably attached to the resulting layer 102 and may be removed and optionally replaced with a different layer 112 having a different peel resistance with layer 102. Alternatively, the layer 112 may be a room-temperature adhesive layer directly fixedly attached to major surface 152 (e.g., after a releasably attached layer 112 has been removed from the major surface 152).

[0034] FIG. 4 is a schematic cross-sectional view of an optical film (or optical stack) 203, according to some embodiments. The optical film 203 can be made by filling or substantially filling spaces between the structures 143 with optically absorptive material (e.g., pigment, such as carbon black, and / or dye in a binder) to define optically absorptive regions 120 between adjacent optically transparent regions 118. Suitable materials for filing the spaces between the resulting structures 143 are described in U.S. Pat. Nos. 8,012,567 (Gaides et al.); 8,213,082 (Gaides et al.); and 9,791,709 (Ouderkirk et al.), for example. In the illustrated embodiment, an adhesive layer 115 is disposed on a major surface 152 of an optical film 213 (e.g., a substrateless light control film), a layer 112 is disposed on layer 115 opposite optical film 213, and a layer 110 is disposed on a major surface 151 of the optical film 213.

[0035] As used herein, a “self-supporting” film is a film that is capable of supporting itself such that it generally maintains its shape without being supported by any layer or substrate that is not part of the film. For example, a film or layer that is sufficiently thick (e.g., greater than about 20 microns) is typically self-supporting, while a thin coating applied onto a substrate is typically not self-supporting since the coating needs the substrate to support the coating.

[0036] As used herein, a “substrateless radiation-cured” film is a film that includes at least one radiation- cured layer and that does not include, and is not directly fixedly attached to, any self-supporting substrate to support the at least one radiation-cured layer. For example, a substrateless radiation-cured film does not include, and is not directly fixedly attached to, a self-supporting primed or unprimed glass or thermoplastic polymer layer (e.g., polyethylene terephthalate (PET) or polycarbonate (PC)) supporting the at least one radiation-cured layer.

[0037] Any of the substrateless radiation-cured light control fdm having opposing first and second major surfaces described herein can be a light control film that includes first and second (typically monolithic) structured layers having respective first and second structured major surfaces disposed on and conforming to one another where the first and second structured layers comprise the respective first and second major surfaces of the light control film and where at least one of the first and second structured layers is a radiation-cured layer. In some embodiments, each of the first and second structured layers is a radiation-cured layer.

[0038] In some embodiments, an optical stack 201, 202, 203 includes a substrateless radiation-cured light control film 211, 212, 213 having opposing first and second major surfaces 151 and 152 and optionally includes a first layer 110 disposed directly on, and substantially coextensive with, the first major surface 151 of the light control film. The first layer 110 can be releasably attached to the first major surface 151 or can be a room -temperature adhesive layer fixedly attached to the first major surface 151. In some embodiments, the light control film 211, 212, 213 includes a plurality of alternating optically transmissive and absorptive regions 118 and 120 disposed between the first and second major surfaces of the light control film; and a first land region 135 integral with a first plurality of the optically transmissive regions 118 (e.g., the optically transmissive regions comprised by first layer 101 (see, e.g., FIG. 3) or all of the optically transmissive regions (see, e.g., FIG. 4)), where the first land region 135 comprises the first major surface 151 and extends from the first major surface 151 to the optically absorptive regions 120. The first land region has an average thickness L (see, e.g., FIG. 1) in a range of about 0.05 micrometers to about 200 micrometers (or the average thickness L can be in another range described elsewhere herein). The optically transmissive regions 118 have an average height H from the first land region 135 to the second major surface 152 along a thickness direction (z-direction) of the light control film and an average width W in a first in-plane direction (x-direction) of the optical film orthogonal to the thickness direction. In some embodiments, H / W is greater than about 1 (or H / W can be in another range described elsewhere herein). In some embodiments, the substrateless radiation-cured light control film 211, 212, 213 is a self-supporting film.

[0039] Layers or elements can be described as substantially coextensive with each other if at least about 60% by area of each layer or element is coextensive with at least about 60% by area of each other layer or element. Here, area refers to the area of a major surface of the layer or element. In some embodiments, for layers or elements described as substantially coextensive, at least about 70%, or at least about 80%, or at least about 90%, or at least about 95% by area of each layer or element is coextensive with at least about 70%, or at least about 80%, or at least about 90%, or at least about 95% by area of each other layer or element.

[0040] In some embodiments, the light control film 211, 212, 213 includes a second layer 102 disposed over a structured first major surface 141 of a first layer 101. The first layer 101 can comprise the first land region 135 and the second layer 102 can comprise a second land region 235 (see, e.g., FIG. 3). The optically transmissive regions 118 of the light control fdm can include a first plurality of optically transmissive regions comprised by the first layer 101 alternating with a second plurality of optically transmissive regions comprised by the second layer 102. The first and second layers 101 and 102 can be first and second radiation-cured layers. In some embodiments, the optical stack 201, 202, 203 further includes a second land region 235 integral with a second plurality of the transmissive regions, where the second land region 235 comprises the second major surface 152 and extends from the second major surface 152 to the absorptive regions 120. In some embodiments, the second land region 235 has an average thickness less than the average thickness of the first land region 135. In some embodiments, the second land region 235 has an average thickness less than about 0.8, 0.6, 0.4, or 0.2 times the average thickness of the first land region 135. The second land thickness can be zero (e.g., the second land 235 may not be present) or can be greater than 0 or greater than about 0.05 or 0.1 micrometers, for example.

[0041] In some embodiments, the second major surface 152 is not fixedly attached to any other layer or is fixedly attached to an adhesive layer 115 (see, e.g., FIG. 4) substantially coextensive with the second major surface 152. It will be understood that the adhesive layer 115 may be optionally omitted from the embodiment schematically illustrated in FIG. 4, or that the adhesive layer 115 may optionally be included in the embodiment of FIG. 3 between layers 112 and 102, or that layer 112 (and / or 110) may optionally be an adhesive layer. In some embodiments, the optical stack 201, 202, 203 further includes an adhesive layer 115 disposed on, and substantially coextensive with, the second major surface 152 of the light control film. In some embodiments, the optical stack further includes a second layer 112 disposed on, substantially coextensive with, and releasably attached to, the adhesive layer 115. In some embodiments, the adhesive layer 115 is omitted. In some embodiments, the optical stack includes a second layer 112 disposed directly on, substantially coextensive with, and releasably attached to, the second major surface 152 of the light control film. In some embodiments, an additional adhesive layer is disposed between layers 101 and 101.

[0042] In some embodiments, after one of the layers 110 or 112 is removed, and adhesive layer (e.g., layer 115) is applied to the exposed surface, the optical film is attached to an article (e.g., a display component) via the adhesive layer, and then the other of the layers 110 or 112 is removed. Alternatively, in some embodiments, the adhesive layer is applied to the article, one of the layers 110 or 112 is removed and the exposed surface is attached to the adhesive layer on the article, then the other of the layers 110 or 112 is removed.

[0043] In some embodiments, an optical film 202 includes a first monolithic radiation-cured layer 101 having a structured first major surface 141 and an opposite second major surface 142; and a second monolithic radiation-cured layer 102 having a structured first major surface 161 and an opposite second major surface 162, where the structured first major surfaces of the first and second radiation-cured layers are disposed on, and substantially conform to, one another. In some embodiments, the structured first major surface having a plurality of structures have an average height H in a thickness direction of the optical film and an average width W in a first in-plane direction of the optical film orthogonal to the thickness direction, where H / W is greater than about 1 (or is in a range described elsewhere herein). In some embodiments, for each of the first and second radiation-cured layers 101 and 102, the second major surface 142, 162 is not fixedly attached to any other layer or is directly fixedly attached to a roomtemperature adhesive layer substantially coextensive with the second major surface. In some embodiments, the optical film 202 further includes a plurality of optically absorptive regions 120 disposed between the first and second monolithic radiation-cured layers. The optically absorptive regions 120 have an average height Hl in the thickness direction and an average width W1 in the first in-plane direction. In some embodiments, Hl / Wl is greater than about 10 (or is in another range described elsewhere herein). The optically absorptive regions 120 may be sufficiently thin (e.g., Hl / Wl at least about 10) that the first major surfaces of the layers 101 and 102 may be considered to substantially conform to one another even when the optically absorptive regions 120 are disposed between the first major surfaces.

[0044] FIG. 5 is a schematic illustration of a peel force measurement, according to some embodiments. In FIG. 5, a layer 310 (e.g., a release layer) is being peeled at a 180 degree angle from an optical film 315 that is attached to a plate 705 via a double-sided tape 703. Unless indicated otherwise, peel force F refers to the peel force per unit length of film orthogonal to the peel direction determined in a 180 degree peel test. The peel test is typically carried out at a peel speed of about 90 in / min, though other peel speeds may be used. In some embodiments, the light control film 211, 212, 213 is formed (e.g., via casting and curing) directly on the first layer 110. In order for the layer 110 to be releasably attached to the resulting light control film, the peel force is typically preferred to be less than about 600 g / in. In order for the structures 143 to release to from the tool and attach to the layer 110, the resulting peel force is typically at least about 30 g / in. However, it may be desired to have a lower peel force in subsequent manufacturing steps, for example. In some embodiments, the light control film 211, 212, 213 is formed on a different layer which is subsequently removed and then the first layer 110 is added. In this case, the first layer 110 can have a peel force of about 2 g / in to about 30 g / in, for example.

[0045] When the optical film is formed on the first layer 110, the desired peel force may be achieved by selecting a suitable substrate (first layer 110) that provides the desired peel force without including a primer or other surface treatment. Alternatively, a substrate can be treated to provide the desired peel force. It has been found, according to some embodiments, that polycarbonate (PC) is a suitable substrate for use with acrylate-based resins, for example, under certain processing conditions. For example, lowering the coating and / or tool temperature and / or lowering the ultraviolet curing intensity in a cast and cure process has been found to result in a lowered peel force of the cast and cured layer from a PC substrate while conventional process conditions result in a high peel force so that the cast and cured layer is not releasably attached to the PC substrate. It has been found that, polyethylene terephthalate (PET) without a primer provides a peel force that is too low to form the desired structures 143 in a cast and cure process but when conventional primers are included under conventional process conditions, the layer 110 becomes fixedly atached to the optical film (e.g., the peel force can be substantially greater than 600 g / in). It has been found that a desired peel force can be achieved by adding release additives (e.g., silicon- based release additives such as silicones available from Shin-Etsu Chemical Co., Ltd., Japan) to a primer (e.g., acrylic emulsion primers such as those available from Dow Chemical Company (Midland, MI) under the RHOPLEX tradename). Lor example, optional primer 492 schematically illustrated in PIG. 5 can include release additives. In some cases, when release additives are included in the primer 492, some of the additives are transferred to major surface 351 of the optical film 315 and are subsequently detectable (e.g., via X-ray photoelectron spectroscopy (XPS)). For example, in some embodiments, the major surface 142 of the layer 101 comprises about 0.3 to 3 atomic percent Si.

[0046] In some embodiments, a second substrate (second layer 112) is coated with a resin (e.g., used to form layer 102) and then applied to the structured surface 141 so that the resin planarizes the structured surface and then the resin is subsequently cured in contact with the structured surface and the second substrate. In such embodiments, the desired peel force may similarly be achieved by selecting a suitable substrate (e.g., PC) that provides the desired peel force without including a primer or other surface treatment, or a substrate can be treated (e.g., PET with modified primer) to provide the desired peel force, and by selecting suitable processing conditions (e.g., lowering tool temperature and / or lowering the ultraviolet curing intensity when the planarizing backfill resin is cured).

[0047] In some embodiments, the first layer 110 is releasably atached to the first major surface 151 and has a 180 degree peel force F from the first major surface 15 lof the light control film 211, 212, 213 that is in a range of about 2 g / in to about 600 g / in. In some such embodiments, or in other embodiments, the peel force F is at least about 2.5, 3, 3.5, 4, 4.5, 5, 6, 8, 10, 15, 20, 30, 40, or 50 g / in. In some such embodiments, or in other embodiments, the peel force F is no more than about 550, 500, 450, 400, 350, 300, or 250 g / in. In some embodiments, the first layer 110 is releasably atached to the first major surface 151 and has a 180 degree peel force F from the first major surface 151 of the light control film that is in a range of about 2, 2.5, 3, 3.5, 4, 4.5, or 5 g / in to about 30, 25, 20, 15 g / in. For example, the peel force can be in a range of about 2 g / in to about 30 g / in, or about 2.5 g / in to about 25 g / in, or about 3 g / in to about 15 g / in. Similarly, in some embodiments, the second layer 112 has a 180 degree peel force F from the second major surface 152 of the light control film that is in a range of about 2, 2.5, 3, 3.5, 4, 4.5, or 5 g / in to about 30, 25, 20, 15 g / in. Such peel force ranges may be preferred for premasks added to the optical film after the original first layer (or original second layer) has been removed. In some embodiments, the first layer 110 is releasably attached to the first major surface 151 and has a 180 degree peel force from the first major surface 151 of the light control film 211, 212, 213 that is in a range of about 30, 35, 40, 45, or 50 g / in to about 600, 500, 400, 300, 250 g / in (and / or the second layer 112 can be releasably atached to the second major surface 152 with a 180 degree peel force in any of these ranges). For example, the peel force can be in a range of about 30 g / in to about 600 g / in, or about 35 g / in to about 500 g / in, or about 40 g / in to about 400 g / in, or about 45 g / in to about 300 g / in, or about 50 g / in to about 250 g / in. Such peel force ranges may be preferred for the original first layer on which the optical film is formed, or the original second layer used to apply the backfill resin. In some embodiments, the desired peel force for the first layer is higher than the desired peel force for the second layer. Any of these 180 degree peel forces can be determined at a peel speed of about 90 in / min.

[0048] In some embodiments, an optical stack includes releasably attached layers on each opposing major surface of an optical film. In some embodiments, the peel forces for the two releasably attached layers can be substantially different (e.g., substantially higher for the first layer 110 when the optical film is formed on first layer 110 than for second layer 112 which may be added after a cast and cured layer of the optical film has been formed on first layer 110). In some embodiments, optical film 202 further includes first and second release liners 110 and 112 disposed directly on, and substantially coextensive with, the second major surface 142, 162 of the respective first and second radiation-cured layers 101 and 102, where for each of the first and second release liners 110 and 112, the release liner has a 180 degree peel force from the corresponding second major surface in a range of about 2 g / in to about 600, 500, 400, 300, or 250 g / in (or in another range described elsewhere herein for layer 110), where a difference between the 180 degree peel forces for the first and second release liners is at least about 20, 25, 30, 35, or 40 g / in. The 180 degree peel force can be determined at a peel speed of about 90 in / min. Here, a release liner is generally a substrate releasably attached to a major surface of the optical film or a radiation-cured layer of the optical film. A release film can be a substrate with a release-treated surface, or with release additives in a primer layer, for example, or can be a substrate (e.g., without release treatment) that the radiation-cured layer is releasably attached to.

[0049] In some embodiments, the first monolithic radiation-cured layer 101 comprises a release agent transferred onto the second major surface 142 of the first monolithic radiation-cured layer 101. In some embodiments, the release agent comprises Si (e.g., the release agent may be or include a silicon- containing compound such as a silicone added to a primer formulation). In some embodiments, the second major surface 142 of the first monolithic radiation-cured layer 101 comprises about 0.3 to 3 atomic percent Si.

[0050] In some embodiments, the optical film or stack 201, 202, 203 further includes a first substrate 110 substantially coextensive with, and releasably attached to, the second major surface 142 of the first monolithic radiation-cured layer 101. In some embodiments, the first substrate 110 comprises a primer layer (e.g., the primer layer 492 schematically illustrated in FIG. 5 may be disposed between layers 101 and 110 of any of FIGS. 2-4) facing the second major surface 142 of the first monolithic radiation-cured layer 101. In some embodiments, the primer layer 492 comprises one or more release agents. In some embodiments, the one or more release agents comprises at least one silicon-containing compound (e.g., at least one silicone). In some embodiments, the first substrate 110 comprises a polycarbonate layer directly contacting the second major surface 142 of the first monolithic radiation-cured layer 101 (e.g., the primer layer 492 may be omitted).

[0051] In some embodiments, an optical film 201, 202, 203 includes a first monolithic radiation-cured layer 101 having a structured first major surface 141 and an opposite second major surface 142, where the structured first major surface 141 comprises a plurality of structures 143 having an average height H in a thickness direction (z -direction) of the optical film and an average width W in an in-plane direction (x-direction) of the optical film, where H / W is greater than about 1 (or is in a range described elsewhere herein), and where the second major surface 142 of the first monolithic radiation-cured layer 101 comprises at least about 0.3, 0.4, or 0.5 atomic percent Si. The second major surface 142 can comprise up to about 5, 4, 3, 2.5, or 2 atomic percent Si. For example, in some embodiments, the second major surface 142 of the first monolithic radiation-cured layer 101 comprises about 0.3 to about 3 atomic percent Si.

[0052] In some embodiments, the optical film further includes a plurality of optically absorptive regions 120 disposed on the structured first major surface 141 and alternating with the structures 143 of the plurality of structures of the structured first major surface 141 (see, e.g., FIG. 4). In some embodiments, the optical film further includes a second monolithic radiation-cured layer 102 having a structured first major surface 161 and an opposite second major surface 162, where the structured first major surfaces 141, 161 of the first and second radiation-cured layers 101 and 102 are disposed on, and substantially conform to, one another (see, e.g., FIG. 3). In some embodiments, the optical film further includes a plurality of optically absorptive regions 120 disposed between the first and second monolithic radiation- cured layers 101 and 102. In some embodiments, the optically absorptive regions have an average height Hl in the thickness direction and an average width W1 in the first in-plane direction, where Hl VI is greater than about 10 (or is in a range described elsewhere herein).

[0053] In some embodiments, an optical stack 202, 203 includes a substrateless radiation-cured optical film 212, 213 including opposing first and second major surfaces 151 and 152 (or 152') and defining structured interface therein (e.g., interface at major surface 141 of layer 101); and first and second release liners 110 and 112 disposed directly on, and substantially coextensive with, the respective first and second major surfaces. In some embodiments, for each of the first and second release liners, the release liner has a 180 degree peel force (e.g., at a peel speed of about 90 in / min) from the corresponding major surface of the optical film that is in a range of about 2 g / in to about 600 g / in (or in a range described elsewhere herein), where a difference between the 180 degree peel forces of the first and second release liners is at least about 20 g / in (or is in a range described elsewhere herein). In some embodiments, the substrateless radiation-cured light control film is a self-supporting film.

[0054] In some embodiments, the substrateless radiation-cured optical film 212, 213 includes a first monolithic radiation-cured layer 101 comprising the first major surface 151 and an opposite structured major surface 141. The structured major surface 141 can include a plurality of structures 143 having an average height H in a thickness direction of the optical film and an average width W in a first in-plane direction of the optical film orthogonal to the thickness direction. In some embodiments, H / W is greater than about 1 (or is in another range described elsewhere herein).

[0055] In some embodiments, the substrateless radiation-cured optical film includes a second monolithic radiation-cured layer 102 comprising the second major surface 152 and an opposite structured major surface 161 substantially conforming to the structured major surface 141 of the first monolithic radiation- cured layer 101. In some embodiments, the substrateless radiation-cured optical film 212 further includes a plurality of optically absorptive regions 120 disposed between the first and second monolithic radiation- cured layers 101 and 102. The optically absorptive regions can have an average height Hl in the thickness direction and an average width W1 in the first in-plane direction, where Hl VI can be greater than about 10 (or can be in a range described elsewhere herein).

[0056] In some embodiments, the substrateless radiation-cured optical film includes a plurality of optically absorptive regions 120 disposed on the structured major surface 141 and alternating with the structures 143 of the plurality of structures of the structured major surface 141. In some embodiments, the second release liner 112 is disposed directly on the structured major surface 141, and the plurality of optically absorptive regions 120 is disposed between the structure major surface 141 and the second release liner 112. In some embodiments, the optical stack includes an adhesive layer which may be considered to be a layer of the optical film. In some embodiments, the optical film further includes an adhesive layer 115 disposed on the structured major surface 141 and comprising the second major surface 152' of the optical film, where the plurality of optically absorptive regions 120 is disposed between the structured major surface and the adhesive layer 115.

[0057] In some embodiments, an optical stack 202, 203 includes a substrateless radiation-cured optical film 212, 213 having opposing first and second major surfaces 151 and 152 and defining a structured interface therein; and a first release liner 110 disposed directly on, and substantially coextensive with, the first major surface 151. In some embodiments, the first release liner 110 has a first 180 degree peel force (e.g., at a peel speed of about 90 in / min) from the first major surface of the optical film that is in a range of about 30 g / in to about 600 g / in (or in another range described elsewhere herein). In some embodiments, the substrateless radiation-cured optical film is a self-supporting film. In some embodiments, the first release liner 110 comprises a first substrate and a primer layer (e.g., corresponding to primer layer 492 disposed on substrate 310 schematically illustrated in FIG. 5) disposed between the first substrate and the first major surface 151 of the optical film. In some embodiments, the primer layer comprises one or more release agents (e.g., silicon-containing release agent(s)). In some embodiments, the optical stack 202, 203 further includes a second release liner 112 disposed directly on, and substantially coextensive with, the second major surface 152 (or 152'). In some embodiments, the second release liner 112 has a second 180 degree peel force (e.g., at a peel speed of about 90 in / min) from the second major surface of the optical film that is less than the first 180 degree peel force by at least about 20 g / in (or by an amount in another range described elsewhere herein).

[0058] In some embodiments, the primer layer has an average thickness less than about 3, 2, 1, 0.8, 0.6, 0.5, or 0.4 micrometers. The primer layer can, for example, be at least 10, 20, 30, 50, 75, or 100 nm thick.

[0059] In some embodiments, the optical film 211, 212, 213 has a total thickness of less than about 300, 275, 250, 225, or 215 micrometers. In some such embodiments, or in other embodiments, the total thickness is at least 90, 100, 125, 150, or 160 micrometers. In some such embodiments, or in other embodiments, the total thickness is less than about 3, 2.75, 2.5, 2.25, 2, 1.75, or 1.5 times the height Hl of the optically absorptive regions 120.

[0060] In some embodiments, H is at least about 30, 40, 50, 55, 60, 65, or 70 micrometers. In some such embodiments, or in other embodiments, H is no more than about 400, 300, 250, 200, 150, 140, or 130 micrometers. For example, in some embodiments, H is in a range of about 30 to 300 micrometers, or about 40 to 200 micrometers, or about 50 to 150 micrometers. In some embodiments, Hl and / or Ht (see, e.g., FIGS. 6-8) are in any of these ranges.

[0061] Any of the optical films of the present description can be incorporated into a display (e.g., after removing any releasably attached layers). In some embodiments, the optical film is a light control film. In some embodiments, the light control film is included in an automotive display. For example, the light control film can be disposed (e.g., with structures 143 extending primarily along a horizontal direction) in an automotive display such that a driver and / or a passenger can view the display through the light control film but such that light (e.g., sunlight) reflected from the display is blocked by the light control film so that it does not reach the driver and / or passenger. The display can be an emissive display (e.g., an organic light emitting diode (OLED) display) including an emissive layer and the light control film may be positioned with the light absorbing regions sufficiently close (e.g., within about 35 micrometers) to the emissive layer to prevent objectionable optical ghosting that might otherwise occur due to reflections at interfaces with the optically absorptive regions.

[0062] FIG. 6 is a schematic cross-sectional view of a display 500, according to some embodiments. In some embodiments, the display 500 includes an emissive layer 400 and a substrateless radiation-cured light control film 314 (e.g., corresponding to any of 211, 212, 213) having opposing first and second major surfaces 151 and 152, where the second major surface 152 faces the emissive layer 400. The light control film 314 includes a plurality of alternating optically transmissive and absorptive regions 118 and 120 disposed between the first and second major surfaces 151 and 152 of the light control film 314; and a first land region 135 integral with a first plurality of the optically transmissive regions, where the first land region 135 comprises the first major surface 151 and extends from the first major surface 151 to the optically absorptive regions 120. The first land region 135 has an average thickness L (see, e.g., FIG. 1) in a range of about 0.05 micrometers to about 200 micrometers (or in a range described elsewhere herein). The optically transmissive regions 118 have an average height Ht from the first land region 135 to the second major surface 152 along a thickness direction (z-direction) of the optical film and an average width W in a first in-plane direction (x-direction) of the optical film orthogonal to the thickness direction. Ht may be equal to the height H (see, e.g., FIG. 4) or Ht may be equal to the height H plus the thickness of any land region 235 (see, e.g., FIG. 3). The thickness of the land region 235 may be small compared to H so that Ht is about equal to H. Ht can be in any range described elsewhere herein for H. In some embodiments, Ht / W is greater than about 1 or Ht / W can be in any range described elsewhere herein for H / W or for Ht / W. For example, Ht / W can be greater than about 2. The display 500 further includes an adhesive layer 250 disposed between the second major surface 152 and the emissive layer 400. In some embodiments, the adhesive layer 250 has an average thickness greater than about 15, 16, 17, 18, 19, 20, 21, 22, or 23 micrometers. The average thickness of the adhesive layer 250 can be up to about 32, 31, 30, 29, 28, 27, 26, or 25 micrometers, for example. In some embodiments, an average minimum distance Z1 between the optically absorptive regions 120 and the emissive layer 400 (unweighted mean over the absorptive regions of the minimum distance between the absorptive region and the emissive layer) is less than about 35, 34, 33, 32, 31, 30, 29, or 28 micrometers. In some embodiments, the adhesive layers 260 and 250 are disposed directly on the respective major surfaces 151 and 152. In some embodiments, the adhesive layer 250 is a room-temperature adhesive layer and / or an optically clear adhesive layer.

[0063] In some embodiments, the first major surface 151 is attached (e.g., directly attached or indirectly attached via a primer layer disposed on first major surface 151) to a room-temperature adhesive layer 260 having an average thickness greater than about 15, 16, 17, 18, 19, 20, 21, 22, or 23 micrometers and being substantially coextensive with the first major surface 151. The average thickness of the adhesive layer 260 can be up to about 100, 75, 50, 40, 35, 32, 31, 30, 29, 28, 27, 26, or 25 micrometers, for example. In some embodiments, an average distance between the first major surface 151 and the roomtemperature adhesive layer 260 is less than about 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or 0.5 micrometers (e.g., the average distance can be zero when no primer layer is included or can be the thickness of the primer layer when the primer layer is included). The room -temperature adhesive layer 260 can be an optically clear adhesive layer. An element 275 can be disposed on the room-temperature adhesive layer. Element 275 may be or include one or more of a cover glass, a circular polarizer, or a touch sensor (e.g., element 275 can correspond to the stack of elements 270, 261 and 280 schematically illustrated in FIG. 7). In some embodiments, the display 500 further includes a circular polarizer 275 attached to the room -temperature adhesive layer 260. An optically clear adhesive layer can have a luminous transmittance of greater than 80, 85, or 90% and an optical haze of less than 10, 5 or 3%. Luminous transmittance and optical haze can be determined according to ASTM DI 003 -21, for example.

[0064] FIG. 7 is a schematic cross-sectional view of a display 501, according to some embodiments. In some embodiments, display 501 includes an emissive layer 400; a substrateless radiation-cured light control film (314 or 211, 212, 213) having opposing first and second major surfaces 151 and 152 where the second major surface 152 faces the emissive layer 400; a first adhesive layer 250 disposed between the second major surface 152 and the emissive layer 400; a cover glass 270; and a second adhesive layer 260 disposed between the cover glass 270 and the first major surface 151, where the second adhesive layer 260 is disposed directly on the first major surface 151. In some embodiments, the first adhesive layer 250 is disposed directly on the second major surface 152. The cover glass, the light control film, the first and second adhesive layers, and the emissive layer can be substantially coextensive with one another. Each of the first and second adhesive layers can be a room-temperature adhesive layer. The light control film can include a plurality of alternating optically transmissive and absorptive regions 118 and 120 disposed between the first and second major surfaces of the light control film; and a first land region 135 integral with a first plurality of the optically transmissive regions, where the first land region 135 comprising the first major surface 151 and extends from the first major surface to the optically absorptive regions 120. The first land region can have an average thickness in a range of about 0.05 to 200 micrometers (or the average thickness can be in another range described elsewhere herein). The optically transmissive regions 118 have an average height Ht from the first land region 135 to the second major surface 152 along a thickness direction (z-direction) of the light control film and an average width W in a first in-plane direction (x-direction) of the light control film orthogonal to the thickness direction. Ht / W can be greater than about 1 or can be in another range described elsewhere herein for Ht / W or for H / W.

[0065] In some embodiments, the display 501 further includes a circular polarizer 276 disposed between the first adhesive layer 250 and the emissive layer 400. In some embodiments, a third adhesive layer 252 is disposed between, and bonds together, the circular polarizer 276 and a display panel 401 comprising the emissive layer 400.

[0066] In some embodiments, an average minimum distance (see, e.g., Z1 schematically illustrated in FIG. 6) between the optically absorptive regions 120 and the emissive layer 400 is less than about 35 micrometers or can be in a range described elsewhere herein. The circular polarizer 276 and adhesive layer 252 can optionally be omitted (or disposed above the light control film) to reduce the average minimum distance.

[0067] An optional element 280 can be disposed on adhesive layer 260 with an optional adhesive layer 261 disposed between the optional element 280 and the cover glass 270. In some embodiments, the element 280 and adhesive layer 261 are omitted so that the cover glass 270 directly contacts the adhesive layer 260. The element 280 can be a touch panel or a circular polarizer (e.g., if circular polarizer 276 is omitted). In some embodiments, the display 501 further includes a touch panel 280 between the cover glass 270 and the second adhesive layer 260. In some embodiments, the display further includes a third adhesive layer 261 (which may alternatively be referred to as a fourth adhesive layer) disposed between, and bonding together, the cover glass 270 and the touch panel 280. In some embodiments, the second adhesive layer 260 is disposed directly on the cover glass 271. In some embodiments, the display 501 further includes a circular polarizer (e.g., element 280 can be a circular polarizer) disposed between the cover glass 270 and the light control film 314.

[0068] In some embodiments, there is no self-supporting substrate disposed between the cover glass 270 and the light control film 314. In some embodiments, there is no self-supporting substrate disposed between the light control film 314 and the first adhesive layer 250. By eliminating self-supporting substrates adjacent to the light control film 314, the number of optical interfaces is reduced and this can result in reduced overall reflectance from the display 501. Antireflective coatings or layers can be included on the cover glass to further reduce reflection. In some embodiments, the cover glass 270 includes an antireflective surface 271 facing away from the light control film 314. The antireflective surface 271 can be a surface including nanostructures for reducing reflection and / or can include an antireflective coating which may include one or more layers. Antireflective nanostructures and (e.g., multilayer) antireflective coatings are known in the art. FIG. 8 is a schematic cross-sectional view of a display 501' which can be equivalent to display 501, according to some embodiments, except that display 501' includes a substrate 510 disposed between the second adhesive layer 260 and the first major surface 151 of the light control film 314. For the display 501', the light control film 314 may be formed directly on substrate 510 in a cast and cure process, for example. The display 501 can have a lower luminous reflectance of ambient light than that of the display 501' because of reflection from the substrate 510. The luminous reflectance is the reflectance of CIE illuminant D65 light weighted by the CIE 1931 tristimulus y function. Luminous reflectance can be determined according to the ASTM E308-22 test standard, for example.

[0069] In some embodiments, for an unpolarized incident light 600 substantially normally incident (e.g., within about 20, 15, 10, or 8 degrees of normal) on a cover glass side of the display 501, 501' (e.g., incident on surface 271 along the +z direction), the display 501 has a luminous reflectance less than that of a comparative display 501' by at least 0.3%, or 0.35%, or 0.38%, or 0.4% (e.g., if R1 and RE are the luminous reflectances of the respective displays 501 and 501' expressed as a percent, Rl' - R1 can be at least 0.3%), where the comparative display 501' is equivalent to the display 501 except that the comparative display 501' includes a biaxially oriented polyethylene terephthalate substrate 510 disposed between the second adhesive layer 260 and the first major surface 151 of the light control film 314. The difference in luminous reflectances can be up to about 0.6% or 0.5%, for example. In some embodiments, for an unpolarized incident light 600 substantially normally incident on a cover glass side of the display 501, 501', the display 501 has a luminous reflectance less than that of a comparative display 501' by at least 0.08%, or 0.09%, or 0.1%, or 0. 11%, where the comparative display 501' is equivalent to the display 501 except that the comparative display 501' includes a polycarbonate substrate 510 disposed between the second adhesive layer 260 and the first major surface 151 of the light control film 314. The difference in luminous reflectances can be up to about 0.2% or 0.15%, for example.

[0070] EXAMPLES

[0071] All parts, percentages, ratios, etc. in the examples are by weight, unless noted otherwise.

[0072] Materials Releasable Top Substrate (e.g., corresponding to layer 112)

[0073] A clear channel film (e.g., corresponding to layer 101) and etched channel film (e.g., corresponding to film 201) were prepared as generally described in U.S. Pat. Appl. Pub. No. 2020 / 0341173 (Schmidt et al.). The structure height H was about 77 micrometers and the structure width W was about 30 micrometers.

[0074] The etched channel film (ECF) was backfilled as follows. Unprimed PET was coated with Resin 2, and then subsequently laminated to the ECF between a superfinished tool and a nitrile or silicone nip roll followed by UV cure. The structures were backfilled with the Resin 2 at the nip which produced the pressure needed to fill the space between the structures. However, the adhesion to the PET was weak, and delamination occurred prior to the winding the film regardless of attempts to improve with process. Since the unprimed PET was intended to be removed after being used to carry the resin to fill the structures, it may be referred to as a sacrificial film (SF).

[0075] An experiment was conducted to explore planarizing with Resin 1 with a three different sacrificial film materials: 4 mil polycarbonate (PC), 2 mil primed PET, 2 and 5 mil unprimed PET. In this experiment, it was found that the adhesion level of PC could be controlled by process variables which contribute to the amount of heat induced into the film, specifically: UV % power (Fusion D-bulbs), coater infrared (IR) temperature and tool temperature. Peel adhesion was measured on an iMass (180° peel, 12 in / min, SF bonded to double sided tape). The line speed was a constant 20fpm for all conditions. Results are provided in the following table for conditions listed in the table. Condition 1 resulted in strong bonding, but delamination was still achieved without noticeable damage to the backfill. Conditions 2 through 4 resulted in good bonding with clean delamination. Condition 5 resulted in damage to the backfill when the SF was peeled. Conditions 6 and 7 resulting in the adhesion being too strong to pull the films apart and the samples were therefore destructed during the test. Primed PET was then tested as an SF, adjusting tool temperature and UV % power. Coater IRs were turned off. Many of the samples allowed the PET to be removed, however the primer would either tear out or transfer in a way that could be seen in the product. Since the substrate (which included the primer) was damaged and not substantially completely removed since visible primer was transferred to the film, the primed PET was not releasably attached to the film. When the tool temperature was dropped from 100°F to 80°F, the resin would “pop off’ of the sidewalls of the louvers, causing cosmetic defects that appear similar to long bubbles in the down-web direction.

[0076] Unprimed PET was then tested with tool and coater IR temperatures set to 190°F and 160°F, respectively. This was carried out on both 2mil PET (20fpm) and 5mil PET (40fpm). The 2mil PET survived the process with very light adhesion (by hand) even though it had no backfill land thickness, but the 5mil PET delaminated before the winder and therefore did not survive the process at 40 fpm (10pm land). Both films were curly, curling toward the ECF. Next, the corona treater was turned on for the 5mil PET at power = 0.4kW, which is equivalent to 0.3J / cm2 at 40fpm. The adhesion level for this condition was destructive.

[0077] Further experiments with PC substrates were conducted using a line speed set at 40 fpm and tool temperature at 100°F for all conditions. Coater IR and UV were chosen as the primary process variables. The clear channel film (CCF) was used as a substitute for the etched channel film (ECF) in this experiment which indicated that adhesion level could be controlled through coater IR temperature and UV % power, although Condition 22 may be an outlier (higher UV resulted in slightly lower adhesion). Adhesion ranged from 81 g / in to 784 g / in via Instron test depending on condition (180° peel, 51b load cell, 90in / min). A small roll was also produced with ECF using the process set points of Condition 27 for samples. Results are provided in the following tables for conditions listed in the table.

[0078] Further experiments were conducted to make CCF structures using Resin 3 on a 4mil PET substrate. Rolls of CCF were first produced with Resin 3, and then they were backfilled in a second pass. In this experiment, nip pressure and coater IR temperature were adjusted as the primary process variables during the backfill step. Tool temperature (100°F), line speed (45fpm), and UV % power (60 / 60 / 0) were all held constant. Furthermore, a 95 durometer nitrile nip was utilized throughout the run. Here, nip pressure did not have a large effect on adhesion to the PC SF, however coater IR temperature did have a significant effect, giving a substantial increase in peel adhesion between 120°F and 130°F from ~50±10g / in to ~275±25g / in respectively as measured with an iMass. Backfill land caliper was also measured. Results are provided in the following table.

[0079] Releasable Bottom Substrate (e.g., corresponding to layer 110)

[0080] Here, the bottom substrate (corresponding to layer 110) on which structures are cast and cured will be referred to as the primary substrate (PF) and the top substrate (corresponding to layer 112) will be referred to as the secondary substrate (SS). Clear channel film (CCF) was made as generally described above with Resin 3 but with 2mil PC (instead of 4mil) as the PS and SS.

[0081] A first series of samples were made for dialing in caliper and adhesion of the PS to the CCF resin, using a rubber covered nip roller and the following constant process set-points: Nip Pressure = 30psi, Line Speed = 45fpm, Tool Temperature = 100°F, Resin & Die Temperature = 130°F, UV % power = 100 / 100 / 0 (UV1 / UV2 / UVPC). With this first series of samples, coater IR temperature was controlled to 125°F, 130°F, 140°F, 150° and 160°F. CCF land thickness was measured between 19pm and 28.25pm, with high land at low coater IR and low land at high coater IR.

[0082] Peel adhesion was also measured on with an iMass (180 degrees, 90 in / min). At 125°F and 130°, adhesion values were measured at 94 g / in and 343 g / in respectively. Samples above 130°F could not be measured since the adhesion was too great. An output roll was then made at 125°F to be used for later experimentation that was not related to this invention. Peel adhesion for this roll was measured in three cross web locations with Left, Center, and Right (L, C, R) values of 108g / in, 330g / in, and 187g / in respectively for an average of 208g / in.

[0083] A second series of samples was then made at 120°F, 125°F, and 130°F. Peel adhesion was measured respectively as 95g / in, 503g / in, and lOlOg / in with this second series. Next, a second output roll to be use for backfill planarization was made at 120°F. With this roll, the L, C, R peel adhesion values measured at 33g / in, 62g / in, and 67g / in respectively for an average of 54g / in. The second roll, which was coated at 120°F, was then used for backfdl planarization as described above. Constant process set-points for backfdl were as follows: Line Speed = 45fpm, Tool Temperature = 100°F, Resin & Die Temperature = 130°F, UV % Power = 60% / 60% / 0%. A smooth superfmished tool was used as was a flat coating nip with Resin 3.

[0084] A series of samples were made by adjusting coater IR (CTR-IR) temperature from 100°F, 110°F and 120°F for the backfdl (BF) process. Peel adhesion of both the PS and the SS was then measured with an iMass (180 degrees, 90 in / min). PS / SS peel adhesion values were as follows: 95 / 49, 108 / 32, 122 / 41g / in at respective coater IR temperature of 100°F, 110°F, 120°F.

[0085] Adhesion increased by 41g / in, 54g / in, and 68g / in at 100°F, 110°F, and 120°F respectively when compared to the first pass PS average adhesion of 54g / in. During the second pass, and therefore a second exposure to heat, and the adhesion increased at acceptably moderate levels such that both the PS and the SS delaminated smoothly from the resin surface, leaving behind an article which was completely substrateless. Total thickness of the resulting article was around 7-8 mils.

[0086] Additional experiments were conducted as described above except that the primed PET was replaced with a PET having a primer coating that included release additives. The primer coating was RHOPLEX-3208 emulsion acrylic primer mixed with an emulsion release polymer that was prepared by mixing MA, NVP, KF-2001, and AA in a ratio by weight of 34.4 / 30.4 / 33.7 / 1.5. When the primer included 0.55 wt.% and 3.5 wt.% of the emulsion release polymer, the surface (e.g., corresponding to surface 142) of the resulting fdm after the PET was removed included about 0. 1 and 1.0 atomic percent Si, respectively, as determined by X-ray photoelectron spectroscopy (XPS).

[0087] Luminous Reflectance

[0088] Luminous reflectance was measured for test samples to show the reduction in reflectance arising from eliminating the substrate of the light control film. A light control film as generally described in U.S. Pat. Nos. 8,012,567 (Gaides et al.) was disposed between glass and black MAKROLON layers with the land and substrate side of the light control film facing the glass layer. CEF3104 adhesive was used to bond the light control film to the glass layer and CEF3502 adhesive was used to bond the light control film to the black MAKROLON layer. Comparative light control films including a biaxially oriented PET (BoPET) substrate or a polycarbonate (PC) substrate and a corresponding exemplary substrateless light control film made as generally described here (see, e.g., FIG. 4 and discussion thereof) were tested using a Minolta CM-3600d spectrophotometer facing the glass layer and using an illuminant D65 and a 2 degree observer. Results for the luminous reflectance were averaged over 5 measurements and are provided in the following table.

[0089] Terms such as “about” will be understood in the context in which they are used and described in the present description by one of ordinary skill in the art. If the use of “about” as applied to quantities expressing feature sizes, amounts, and physical properties is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, “about” will be understood to mean within 10 percent of the specified value. A quantity given as about a specified value can be precisely the specified value. For example, if it is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, a quantity having a value of about 1, means that the quantity has a value between 0.9 and 1. 1, and that the value could be 1.

[0090] Terms such as “substantially” will be understood in the context in which they are used and described in the present description by one of ordinary skill in the art. If the use of “substantially” with reference to a property or characteristic is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description and when it would be clear to one of ordinary skill in the art what is meant by an opposite of that property or characteristic, the term “substantially” will be understood to mean that the property or characteristic is exhibited to a greater extent than the opposite of that property or characteristic is exhibited.

[0091] All references, patents, and patent applications referenced in the foregoing are hereby incorporated herein by reference in their entirety in a consistent manner. In the event of inconsistencies or contradictions between portions of the incorporated references and this application, the information in the preceding description shall control.

[0092] Descriptions for elements in figures should be understood to apply equally to corresponding elements in other figures, unless indicated otherwise. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and / or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations, or variations, or combinations of the specific embodiments discussed herein.

[0093] Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.

Claims

What is claimed is:

1. An optical stack comprising: a substrateless radiation-cured light control film having opposing first and second major surfaces, the light control film comprising: a plurality of alternating optically transmissive and absorptive regions disposed between the first and second major surfaces of the light control film; and a first land region integral with a first plurality of the optically transmissive regions, the first land region comprising the first major surface and extending from the first major surface to the optically absorptive regions, the first land region having an average thickness in a range of about 0.05 to 200 micrometers, the optically transmissive regions having an average height H from the first land region to the second major surface along a thickness direction of the light control film and an average width W in a first in-plane direction of the light control film orthogonal to the thickness direction, H / W greater than about 1 ; and a first layer disposed directly on, and substantially coextensive with, the first major surface of the light control film, the first layer being releasably attached to the first major surface or being a roomtemperature adhesive layer fixedly attached to the first major surface.

2. The optical stack of claim 1, wherein the first layer is releasably attached to the first major surface and has a 180 degree peel force from the first major surface of the light control film that is in a range of about 2 g / in to about 30 g / in.

3. The optical stack of claim 1, wherein the first layer is releasably attached to the first major surface and has a 180 degree peel force from the first major surface of the light control film that is in a range of about 30 g / in to about 600 g / in.

4. The optical stack of claim 1 further comprising an adhesive layer disposed on, and substantially coextensive with, the second major surface of the light control film.

5. The optical stack of claim 1 further comprising a second layer disposed directly on, substantially coextensive with, and releasably attached to, the second major surface of the light control film.

6. An optical film comprising: a first monolithic radiation-cured layer having a structured first major surface and an opposite second major surface, the structured first major surface having a plurality of structures having an average height H in a thickness direction of the optical film and an average width W in a first in-plane direction of the optical film orthogonal to the thickness direction, H / W greater than about 1 ; anda second monolithic radiation-cured layer having a structured first major surface and an opposite second major surface, the structured first major surfaces of the first and second radiation-cured layers disposed on, and substantially conforming to, one another, wherein for each of the first and second radiation-cured layers, the second major surface is not fixedly attached to any other layer or is directly fixedly attached to a room-temperature adhesive layer substantially coextensive with the second major surface.

7. The optical film of claim 6 further comprising a first substrate substantially coextensive with, and releasably attached to, the second major surface of the first monolithic radiation-cured layer.

8. The optical film of claim 7, wherein the first substrate comprises a primer layer facing the second major surface of the first monolithic radiation-cured layer.

9. The optical film of claim 8, wherein the primer layer comprises one or more release agents.

10. The optical film of claim 7, wherein the first substrate comprises a polycarbonate layer directly contacting the second major surface of the first monolithic radiation-cured layer.

11. A display comprising: an emissive layer; a substrateless radiation-cured light control film having opposing first and second major surfaces, the second major surface facing the emissive layer, the light control film comprising: a plurality of alternating optically transmissive and absorptive regions disposed between the first and second major surfaces of the light control film; and a first land region integral with a first plurality of the optically transmissive regions, the first land region comprising the first major surface and extending from the first major surface to the optically absorptive regions, the first land region having an average thickness in a range of about 0.05 micrometers to about 200 micrometers, the optically transmissive regions having an average height Ht from the first land region to the second major surface along a thickness direction of the light control film and an average width W in a first in-plane direction of the light control film orthogonal to the thickness direction, Ht / W greater than about 1 ; and an adhesive layer disposed between the second major surface and the emissive layer and having an average thickness greater than about 15 micrometers, wherein an average minimum distance between the optically absorptive regions and the emissive layer is less than about 35 micrometers; and wherein the first major surface is attached to a room-temperature adhesive layer having an average thickness greater than about 15 micrometers and being substantially coextensive with the firstmajor surface, an average distance between the first major surface and the room-temperature adhesive layer being less than about 10 micrometers.

12. A display comprising: an emissive layer; a substrateless radiation-cured light control film having opposing first and second major surfaces, the second major surface facing the emissive layer, the light control film comprising: a plurality of alternating optically transmissive and absorptive regions disposed between the first and second major surfaces of the light control film; and a first land region integral with a first plurality of the optically transmissive regions, the first land region comprising the first major surface and extending from the first major surface to the optically absorptive regions, the first land region having an average thickness in a range of about 0.05 to 200 micrometers, the optically transmissive regions having an average height Ht from the first land region to the second major surface along a thickness direction of the light control film and an average width W in a first in-plane direction of the light control film orthogonal to the thickness direction, Ht / W greater than about 1 ; a first adhesive layer disposed between the second major surface and the emissive layer; a cover glass; and a second adhesive layer disposed between the cover glass and the first major surface, the second adhesive layer disposed directly on the first major surface; wherein the cover glass, the light control film, the first and second adhesive layers, and the emissive layer are substantially coextensive with one another; and wherein each of the first and second adhesive layers is a room-temperature adhesive layer.

13. An optical film comprising: a first monolithic radiation-cured layer having a structured first major surface and an opposite second major surface, the structured first major surface having a plurality of structures having an average height H in a thickness direction of the optical film and an average width W in an in-plane direction of the optical film, H / W greater than about 1, wherein the second major surface of the first monolithic radiation-cured layer comprises about 0.3 to 3 atomic percent Si.

14. An optical stack comprising: a substrateless radiation-cured optical film comprising opposing first and second major surfaces and defining a structured interface therein; and first and second release liners disposed directly on, and substantially coextensive with, the respective first and second major surfaces,wherein for each of the first and second release liners, the release liner has a 180 degree peel force from the corresponding major surface of the optical film that is in a range of about 2 g / in to about 600 g / in, a difference between the 180 degree peel forces of the first and second release liners being at least about 20 g / in.

15. An optical stack comprising: a substrateless radiation-cured optical film comprising opposing first and second major surfaces and defining a structured interface therein; and a first release liner disposed directly on, and substantially coextensive with, the first major surface, wherein the first release liner has a first 180 degree peel force from the first major surface of the optical film that is in a range of about 30 g / in to about 600 g / in.

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