Optical Assembly

Abstract

To provide an optical assembly including an optical element directly insert-molded on an optical laminate.SOLUTION: An optical laminate 120 includes an optical film and may include a liner in which the optical film is placed between an optical element and the liner. The liner, if included, can be removed from the optical film without substantially damaging the optical film. An outermost layer of the optical film may be diffusion bonded to a main surface of an optical element 110.SELECTED DRAWING: Figure 1A

Description

[Background technology]

[0001] In various applications, an optical film may be disposed over an optical element. Summary of the Invention

[0002] In some aspects herein, an optical assembly is provided that includes an optical element that is insert molded directly onto an optical stack that includes an optical film and a liner, the optical film being disposed between the optical element and the liner, and the liner being removable from the optical film without substantially damaging the optical film.

[0003] In some aspects herein, an optical assembly is provided that includes an integrally formed multilayer optical film and a first optical element that is injection insert molded directly onto the optical film. The optical film includes a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference. Each location over at least 80% of the total area of ​​the optical film has a reflectivity greater than about 80% for normally incident light having the same predetermined wavelength and the same first polarization state. The melting temperature of the first optical element is substantially higher than the glass transition temperature of the optical film.

[0004] In some aspects herein, an optical assembly is provided that includes an integrally formed multilayer optical film and an optical element that is insert molded directly onto the optical film. The optical film includes a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference. The optical film is diffusion bonded to the optical element. The bond of the optical film to the optical element is stronger than the interlayer bond between at least one pair of directly adjacent layers in the optical film.

[0005] In some aspects herein, an optical assembly is provided that includes an integrally formed multilayer optical film and an optical element that is insert molded directly onto the optical film. The optical film is diffusion bonded to the optical element. The optical film includes a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference. Each location over at least 90% of the total area of ​​the optical film has a reflectivity of greater than about 90% for normally incident light having the same predetermined wavelength and the same first polarization state.

[0006] In some aspects herein, an optical assembly is provided that includes an optical film and a lens that is insert molded directly onto the optical film. The optical film includes a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference. Each location over at least 90% of the total area of ​​the optical film has a reflectivity greater than 90% for normally incident light having the same predetermined wavelength and the same first polarization state. The lens has an optical retardance that varies more along its largest lateral dimension in a first direction and less along its largest lateral dimension in an orthogonal second direction. The optical retardance at each location on the lens is about 10 nm or less.

[0007] In some aspects herein, an optical assembly is provided that includes a lens and a multilayer optical film having opposing first and second major surfaces, the first major surface being disposed on a first portion of a first side of the lens. Each location over at least 80% of the total area of ​​the multilayer optical film has a reflectivity of greater than about 80% for normally incident light having the same predetermined wavelength and the same first polarization state. A second portion of the first side of the lens is substantially coplanar with the second major surface of the multilayer optical film.

[0008] In some aspects herein, an optical assembly is provided that includes a lens and an optical stack disposed on a major surface of the lens, the lens at least partially wrapping around an edge of the optical stack.

[0009] In some embodiments herein, an optical assembly includes a lens having a first major surface defining a curved recess therein, and a multilayer optical film adhesively conforming to the curved recess.

[0010] In some aspects herein, an optical assembly is provided that includes an optical film and a lens injection molded directly onto the optical film. Each location over at least 80% of the total area of ​​the optical film has a reflectivity of greater than about 80% for normally incident light having the same predetermined wavelength and the same first polarization state. The lens has an optical retardance of about 10 nm or less at each location over at least 80% of the major surface of the lens. The lens thickness at the first lens location is at least about 20% greater than the lens thickness at the second lens location. [Brief description of the drawings]

[0011] [Figure 1A] FIG. 2 is a schematic cross-sectional view of an optical assembly. [Figure 1B] FIG. 2 is a schematic cross-sectional view of an optical assembly. [Figure 1C] FIG. 1 is a schematic cross-sectional view of an optical element. [Diagram 2] FIG. 2 is a schematic cross-sectional view of an optical laminate. [Diagram 3] FIG. 1 is a schematic cross-sectional view of an optical film. [Figure 4A] FIG. 2 is a schematic cross-sectional view of an optical laminate. [Figure 4B] FIG. 4B is a schematic bottom view of the optical stack of FIG. 4A. [Figure 4C] FIG. 2 is a schematic cross-sectional view of an optical laminate. [Figure 4D] FIG. 2 is a schematic cross-sectional view of an optical laminate. [Figure 5A] FIG. 2 is a schematic cross-sectional view of an optical assembly. [Figure 5B] FIG. 2 is a schematic cross-sectional view of an optical assembly. [Figure 5C] FIG. 2 is a schematic cross-sectional view of a lens. [Figure 5D] FIG. 5D is a schematic top view of the lens of FIG. 5C. [Figure 6A]FIG. 2 is a schematic cross-sectional view of an optical assembly. [Figure 6B] FIG. 2 is a schematic cross-sectional view of an optical assembly. [Figure 7A] 1 illustrates a process for injection insert molding an optical element onto an optical film. [Figure 7B] 1 illustrates a process for injection insert molding an optical element onto an optical film. [Figure 7C] 1 illustrates a process for injection insert molding an optical element onto an optical film. [Figure 7D] 1 illustrates a process for injection insert molding an optical element onto an optical film. [Figure 7E] 1 illustrates a process for injection insert molding an optical element onto an optical film. [Figure 8A] FIG. 2 is a schematic cross-sectional view of an optical assembly. [Figure 8B] FIG. 2 is a schematic cross-sectional view of an optical assembly. [Figure 8C] FIG. 2 is a schematic cross-sectional view of an optical assembly. [Figure 9] FIG. 1 is a schematic cross-sectional view of an optical element. [Figure 10] FIG. 2 is a schematic top view of a lens. Detailed Description of the Invention

[0012] In the following description, reference is made to the accompanying drawings, which 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 disclosure. Accordingly, the following detailed description is not to be taken in a limiting sense.

[0013] There are a wide variety of applications in which it is desirable to place an optical film on an optical element. For example, a display may utilize a polarizing beam splitter (PBS) in which the optical film is placed on the hypotenuse of a prism. The optical film may be a multilayer polymer optical film that reflects or transmits light primarily by optical interference. As another example, a display system may utilize a folded optical system that includes a partial reflector and a reflective polarizer spaced adjacent to each other, as described, for example, in U.S. Pat. No. 9,557,568 (Ouderkirk et al.). In some cases, it is desirable to place the reflective polarizer on a major surface of a lens.

[0014] The optical assemblies herein typically include an optical film, such as an integrally formed multilayer optical film, disposed on an optical element, such as an optical lens. For example, the optical film may be disposed on a major surface of any of a biconvex lens, a plano-convex lens, a positive meniscus lens, a negative meniscus lens, a plano-concave lens, or a biconcave lens. In some embodiments, the optical element is injection molded onto the optical film such that a diffusion bond is formed between the optical film and the optical element. In some embodiments, the diffusion bond is stronger than the interlayer bond between adjacent layers in the optical film. In some embodiments, the optical element resulting from the insert molding process has an optical birefringence of less than 10 nm, and in some embodiments, the optical birefringence varies more along one direction than along an orthogonal direction.

[0015] FIG. 1A is a schematic cross-sectional view of an optical assembly 100 including an optical element 110 and an optical stack 120. In some embodiments, the optical element 110 is insert molded directly onto the optical stack 120. The optical element can be insert molded onto the optical stack by inserting the optical stack into a mold and molding the optical element onto the optical stack. The insert molding can be injection insert molding, compression insert molding, or some other form of insert molding. The material forming the optical element 110 is preferably melted when it comes into contact with the optical stack 120, so that the material forms a suitable bond with the optical stack 120 without including any additional adhesive layer. In some embodiments, the material forming the optical element 110 and the material forming the outermost surface of the optical stack 120 are selected to be compatible with each other such that a suitable diffusion bond is formed between the optical stack 120 and the optical element 110. For example, in some embodiments, similar or otherwise compatible (e.g., partially miscible) polymers are used for the materials forming the optical element 110 and the materials forming the outermost surface of the optical stack 120 facing the optical element 110. Similar or compatible polymers may have, for example, melting points that are approximately equal (e.g., within 50° C., or within 30° C., or within 20° C., or within 10° C.). In some embodiments, the optical stack 120 includes an optical film that includes multiple alternating polymer layers, where the bond of the optical film to the optical element 110 is stronger than the interlayer bond between at least one pair of immediately adjacent layers in the optical film.

[0016] In some embodiments, the optical element 110 is a lens. In some embodiments, the lens has refractive optical power in at least one direction. For example, the optical element 110 may be a cylindrical lens with optical power in one direction (e.g., the x-direction), or a spherical or aspherical lens with optical power in two directions (e.g., the x-direction and the y-direction). In some embodiments, other types of optical elements may be used. For example, the optical element may be a prism, and the optical stack 120 may be disposed on a face (e.g., a curved or substantially flat hypotenuse) of the prism.

[0017] In some embodiments, the optical stack 120 is disposed on a curved major surface of the optical element 110, and in some embodiments, the optical stack 120 is disposed on a substantially flat major surface of the optical element 110. The optical stack 120 may be disposed on the curved major surface of the optical element 110 such that at least one location on a first curved major surface of the optical element 110 has a radius of curvature in each of two mutually orthogonal directions (e.g., the x-direction and the y-direction) in a range from about 6 mm to about 1000 mm. A surface may be described as substantially flat if the best fit sphere has a radius greater than about 2000 mm.

[0018] The optical stack 120 may be or may include an optical film. In some embodiments, the optical film is a mirror film, and in some embodiments, the optical film is a reflective polarizer. Examples of reflective polarizers include multilayer polymer film reflective polarizers and wire grid polarizers, which may include wires that extend generally within the block axis of the reflective polarizer and are disposed on a substrate, which may be a polymer substrate. In some embodiments, the optical stack 120 is an integrally formed multilayer optical film that includes a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference. In some embodiments, the optical stack 120 includes an integrally formed multilayer optical film and at least one additional layer that is not integral with the multilayer optical film. As used herein, a first element that is "integrally formed" with a second element means that the first and second elements are not manufactured separately, but are manufactured together and then bonded. "Integral formed" includes manufacturing the first element and then manufacturing the second element on the first element. An optical film (e.g., a reflective polarizer) that includes multiple layers is integrally formed when the layers are manufactured together (e.g., combined as a melt stream and then cast onto a chill roll to form a cast film having each layer, and then orient the cast film) rather than being manufactured separately and then bonded. An additional layer that is not integral with the integrally formed multilayer optical film means that the additional layer is not integrally formed with the multilayer optical film. For example, the additional layer can be formed separately and then adhered to the multilayer optical film (e.g., laminated with an optically clear adhesive).

[0019] In some embodiments, the optical stack, or the optical films included in the optical stack, are mirror (e.g., visible mirror or infrared mirror) films or reflective polarizer films. The optical stack 120 in FIG. 1A is depicted as a reflective polarizer, and the optical stack 120b in FIG. 1B is depicted as a mirror. In some embodiments, each location over at least about 80%, or at least about 90%, or at least about 95%, or all of the total area of ​​the optical stack 120 or the optical films included in the optical stack 120 has a reflectivity of greater than about 80%, or greater than about 90%, or greater than about 95% for normally incident light having the same predetermined wavelength and the same first polarization state. The predetermined wavelength may be any or all wavelengths within a predetermined wavelength range. The predetermined wavelength range may be the visible range (400 nm to 700 nm) and / or may include infrared and / or ultraviolet wavelengths. In some embodiments, the predetermined wavelength is about 550 nm.

[0020] In some embodiments, each location across at least about 80%, or at least about 90%, or at least about 95%, or all of the total area of ​​the optical stack 120 or the optical films included in the optical stack 120 has a reflectivity of greater than about 80%, or greater than about 90%, or greater than about 95%, for normally incident light having the same predetermined wavelength and the same second polarization state orthogonal to the first polarization state.

[0021] The polarization state can be characterized by the direction of the electric field vector, which defines the axis along which normally incident light is tangent to the optical film. The polarization state can be considered to be the same if the axes tangent to the optical film or optical stack along the electric field of normally incident light at two different locations on the optical film are in parallel planes that each intersect the optical film along the curvature. The polarization state can similarly be considered to be the same if the axes tangent to the optical film or optical stack and perpendicular to the electric field of normally incident light at two different locations on the optical film are in parallel planes that each intersect the optical film along the curvature. For example, light traveling parallel to the negative z direction and incident on a vertex of the optical stack 120 (the point with the maximum z coordinate) can have a first polarization state with an electric field along the y direction and a second polarization state with an electric field along the x direction. The first polarization state 163 of the light ray 113 is the same as the first polarization state of the light incident on the vertex, since in both cases the electric field vector at the point of incidence is in a plane parallel to the yz plane. The second polarization state 193 of light ray 184 is the same as the second polarization state of light incident on the vertex because in both cases the electric field vector at the point of incidence is orthogonal to an axis (parallel to the y-axis) that is tangent to the optical film and lies in a plane parallel to the yz-plane.

[0022] In some embodiments, the optical stack 120 includes an optical film that is a reflective polarizer that substantially reflects normally incident light having a predetermined wavelength and a block polarization state and substantially transmits normally incident light having a predetermined wavelength and an orthogonal pass polarization state. Substantially reflecting can be understood to mean at least 60% reflectance, and substantially transmitting can be understood to mean at least 60% transmission. The block polarization state of the reflective polarizer can be described as the polarization state that has the lowest transmission through the reflective polarizer, and the pass polarization state is the orthogonal polarization state. The block polarization state at the center of the reflective polarizer can be a first polarization state. The block polarization state can vary from the first polarization state away from the center position due to, for example, changes induced by thermoforming the optical film into a curved shape (e.g., the block axis can vary by less than about 5 degrees, or less than about 2 degrees in plan view).

[0023] A light ray 113 having a predetermined wavelength λ is incident near-normally on the optical stack 120 in a first polarization state 163 and reflects from the optical stack 120 as reflected ray 116. A small non-zero angle of incidence is shown for ease of illustration. In this case, the light ray 116 is shown diagrammatically as being completely reflected from the optical stack 120 (100% reflectance and 0% transmission), however, the optical stack 120 may have less than 100% reflectance and may have some light of the first polarization state 163 transmitted through the optical stack 120. A light ray 184 having a predetermined wavelength λ is incident near-normally on the optical stack 120 in a second polarization state 193 and is transmitted through the optical stack 120 as transmitted ray 186. In this case, light ray 184 is shown diagrammatically as being completely transmitted from the optical stack 120 (100% transmission and 0% reflectance), although the optical stack 120 may have less than 100% transmission and may have some light in the second polarization state 193 reflected from the optical stack 120 (e.g., due to Fresnel reflection). The first polarization state 163 may be, or may be approximately, the block polarization state of a reflective polarizer in the optical stack 120 (e.g., a block axis within 2 degrees of the axis of the first polarization state 163 in a plan view). The second polarization state 193 may be, or may be approximately, the pass polarization state of a reflective polarizer in the optical stack 120 (e.g., a pass axis within 2 degrees of the axis of the second polarization state in a plan view).

[0024] In other embodiments, the optical stack 120 includes a mirror film that substantially reflects both the first polarization state 163 and the second polarization state 193. This is illustrated in FIG. 1B, which shows an optical assembly 100b similar to the optical assembly 100, except that the optical stack 120 is replaced with an optical stack 120b. The optical assembly 100b may have the properties described for the optical assembly 100, except for the reflective and transmissive properties for the second polarization state 193. In FIG. 1B, the light ray 184 is illustrated generally as being completely reflected from the optical stack 120b (100% reflectance and 0% transmission), although the optical stack 120b may have less than 100% reflectance and may have some light of the second polarization state 193 transmitted through the optical stack 120b. The optical stacks 120 and 120b may include optical films that substantially determine the reflectance and transmittance of the respective optical stacks.

[0025] The reflectance and / or transmittance may be specified over a region A that is a certain fraction of the total area of ​​the optical stack or optical film. For example, region A may be at least about 80% of the total area, excluding, for example, 20 percent of the total area near the periphery of the optical stack. In some embodiments, region A is the total area of ​​the optical stack 120 or 120b, or the total area of ​​the optical films included in the optical stack.

[0026] The optical assembly 100 may further include a second optical element (not shown in FIGS. 1A-1B) disposed on the optical stack 120 opposite the optical element 110. For example, the optical element 110 may be a first lens and the second optical element may be a second lens.

[0027] 1C is a schematic cross-sectional view of optical element 110 showing a maximum thickness h1 and a minimum thickness h2. The thickness at a location of the optical element can be described as the shortest distance through that location and through the opposing major surfaces of the optical element. In some embodiments, optical element 110 is a lens. In some embodiments, the lens has a lens thickness of about 50% or less ((H2-H1)) / H1.* In some embodiments, the lens thickness of the lens varies from position to position by at least about 20% ((H2-H1)) / H1. * 100% varies with position by at least about 20%, or at least about 30%, or at least about 40%, or at least about 50%, or at least about 60%, or at least about 75%, or at least about 100%, or at least about 150%, or at least about 200%. A lens thickness that varies with position by at least a specified percentage has at least one first lens position that is greater than the lens thickness at at least one second lens position by at least a specified percentage. For example, if H2 is at least 1.5 times H1, then the lens thickness varies with position by at least 50%, and the thickness H2 at the center position is at least 50% greater than the thickness H1 at the edge position.

[0028] 2 is a schematic cross-sectional view of an optical stack 220 including an integrally formed multilayer optical film 222 and an additional film or layer 230 bonded to the optical film 222 via an optional adhesive layer 232. The optical film 222 includes a plurality of interference layers 224 and non-interference layers 226a and 226b. The plurality of interference layers 224 includes alternating first polymer layers 221 and second polymer layers 223.

[0029] The multiple interference layers 224 reflect or transmit light primarily through optical interference. An interference layer can be described as reflecting or transmitting light primarily through optical interference if the reflectance and transmittance of the interference layer can be reasonably described by optical interference or can be reasonably accurately modeled as a result of optical interference. Such interference layers are described, for example, in U.S. Pat. No. 5,882,774 (Jonza et al.) and U.S. Pat. No. 6,609,795 (Weber et al.) and can be made by co-extruding a melt stream having alternating polymer layers, casting the melt stream to form a cast film, and then orienting the cast film (biaxially for a mirror film or substantially uniaxially for a reflective polarizing film) as known in the art to produce a birefringent layer (e.g., all other layers in the interference layer can be birefringent, while all other layers remain substantially isotropic). Adjacent pairs of interference layers with different refractive indices reflect light when the pairs have a combined optical thickness (refractive index x physical thickness) of 1-2 wavelengths of light. The interference layer typically has a physical thickness of less than about 200 nanometers. The non-interference layer has an optical thickness too large to contribute to the reflection of visible light by interference. Typically, the non-interference layer has a physical thickness of at least 1 micrometer, or at least three times the predetermined wavelength, or at least three times the maximum wavelength of the predetermined range. In some embodiments, two or more non-interference layers are included. In some embodiments, at least one non-interference layer (in the illustrated embodiment, non-interference layers 226a and 226b) is integrally formed with the plurality of interference layers 224 and does not reflect or transmit light primarily by optical interference.

[0030] In some embodiments, the additional layer 230 is a liner peelably bonded to the optical film 222. A liner that is bonded to the optical film but can be cleanly removed from the optical film without substantially damaging the optical film can be described as peelably bonded to the optical film. In some embodiments, a liner peelably bonded to the optical film can be removed from the optical film without visible damage to the optical film. In some embodiments, when a liner is removable from the optical film without substantially damaging the optical film, for each location over at least 80% of the total area of ​​the optical film, the difference between the reflectance of the optical film at that location before and after the liner is removed is less than about 5% (e.g., the absolute value of the difference in reflectance before and after the liner is removed divided by the reflectance after the liner is removed multiplied by 100% can be less than 5%), or less than about 2%, or less than about 1%. For example, in some embodiments, the optical film includes a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference, each location over at least about 80% of the total area of ​​the optical film has a reflectivity of greater than about 80% for normally incident light having the same predetermined wavelength and the same first polarization state, and the liner is releasably bonded to the optical film such that the difference in reflectivity of the optical film at that location before and after the liner is removed is less than about 5%, or less than about 2%, or less than about 1%. The releasably bonded liner may include a substrate having an adhesive layer that bonds strongly to the substrate but weakly to the optical film. For example, the liner may include a thin layer of low tack adhesive applied to a substrate that has been surface treated to increase bonding to the adhesive. Other suitable liners include those that electrostatically bond to the optical film, for example, as described in U.S. Pat. No. 6,991,695 (Tait et al.). One example of a suitable liner is OCPET NSA33T available from Sun A Kaken Co, Ltd.

[0031] In some embodiments, the optical stack 220 is formed into a curved shape, and then the optical components are insert molded onto the optical stack on the side opposite the additional layer 230. In some embodiments, the additional layer 230 is a liner that is attached to the optical film 222 prior to forming the optical stack 220 into a curved shape, such that the liner is removable from the resulting optical assembly after the optical elements are insert molded onto the optical stack 220 without substantially damaging the optical film 222.

[0032] In some embodiments, the additional layer 230 is optically transparent. In some embodiments, the additional layer 230 is a protective layer, which may be an optically transparent protective layer. A layer (e.g., an adhesive layer or a hard coat layer) can be described as optically transparent if it has a haze of less than 10% transmission. Haze can be determined according to the ASTM D1003-13 test standard. A suitable instrument for measuring haze is the Haze-Gard Plus Haze Meter (BYK Gardner, Columbia, Maryland).

[0033] FIG. 3 is a schematic diagram of an optical film 322 that can be optionally used in an optical stack (e.g., in place of the optical film 222 in the optical stack 220). The optical film 322 includes a first packet 224-1 and a second packet 224-2 of interference layers separated by a non-interference layer 326b. The optical film 322 further includes outer non-interference layers 326a and 326c. The optical film 322 may be integrally formed. The first packet 224-1 and the second packet 224-2 can utilize overlapping thickness ranges, for example, as described in U.S. Provisional Patent Application No. 62 / 467,712, filed March 6, 2017, entitled "High Contrast Optical Film and Devices Including the Same," which provides a reflective polarizer with a high contrast ratio (the ratio of pass-state transmittance to block-state transmittance) or a mirror with low leakage. In some embodiments, reflective polarizers utilizing packets having overlapping thickness ranges have a block state reflectance of at least 99%, or at least 99.5%, or at least 99.8%, for example.

[0034] In some embodiments, the optical film 222 or 322 has a reflectivity of greater than about 80% for normally incident light having a predetermined wavelength and the same first polarization state. In some embodiments, even after the optical film or optical stack (e.g., optical stack 220) is thermoformed into a curved shape and optical elements are molded onto the optical film or stack, the optical film 222 or 322 or other optical films herein still have a high reflectivity. For example, in some embodiments, each location over at least about 80%, or at least about 90%, or all of the total area of ​​the optical film has a reflectivity of greater than about 80%, or greater than about 90%, for normally incident light having the same predetermined wavelength and the same first polarization state. The optical film may also be low leaky even after it is formed and have optical elements molded onto it. For example, in some embodiments, each location over at least about 80%, or at least about 90%, or all of the total area of ​​the optical film has a transmission of less than about 5%, or less than about 2%, or less than about 1%, or less than about 0.6%, or less than about 0.5% for normally incident light having the same predetermined wavelength and the same first polarization state. In some embodiments, the optical film is a reflective polarizer that substantially reflects normally incident light having a predetermined wavelength and a block polarization state and substantially transmits normally incident light having a predetermined wavelength and an orthogonal pass polarization state. In some embodiments, each location over at least about 80%, or at least about 90%, or all of the total area of ​​the reflective polarizer has a transmission of less than about 5%, or less than about 2%, or less than about 1%, or less than about 0.6%, or less than about 0.5% for normally incident light having a predetermined wavelength and a block polarization state.

[0035] In some embodiments, the optical stack includes an optical film and an additional layer that extends beyond the periphery of the optical film. For example, the additional layer may extend in all directions tangent to the optical film along the periphery of the optical film. FIGS. 4A-4B are schematic side and bottom views of an optical stack 420 including an optical film 422 and an additional layer 430. In some embodiments, the optical film 422 is an integrally formed multilayer optical film (e.g., the optical film 422 may correspond to the optical film 222 or 322), as further described elsewhere herein. In some embodiments, the additional layer 430 is a protective layer (e.g., an optically clear hard coat) or a liner. In some embodiments, the additional layer 430 is a liner that is peelably bonded to the optical film 422. The optical film 422 has a periphery 425, and the additional layer 430 completely covers the optical film 422 and extends beyond the periphery 425 of the optical film 422. In some embodiments, the interface 428 between the additional layer 430 and the optical film 422 is optically smooth. In other embodiments, the interface 428 is textured. A surface is optically smooth if it is sufficiently smooth that there is substantially no scattering due to surface roughness. For example, if the surface roughness parameter Ra is significantly smaller than the wavelength of visible light (e.g., less than 50 nm), the optical effects from the surface roughness can be neglected and the surface can be described as optically smooth. A textured surface typically includes a texture with a sufficiently large amplitude that the surface is not optically smooth.

[0036] In some embodiments, additional layer 430, or other additional layers described elsewhere herein, is a protective layer (e.g., a layer formed by curing a coating) or a protective film (e.g., a film having a protective coating). In some embodiments, the protective coating comprises an at least partially cured composition, which composition comprises: a) 70 to 90 weight percent, based on the total weight of components a) to d), of a urethane (meth)acrylate compound having an average (meth)acrylate functionality of 3 to 9; b) 5 to 20% by weight, based on the total weight of components a) to d), of a (meth)acrylate monomer having a (meth)acrylate functionality of 1 to 2, which is not a urethane (meth)acrylate compound; c) 0.5 to 2 wt. % of a silicone (meth)acrylate, based on the total weight of components a) to d); and d) an optional effective amount of a photoinitiator.

[0037] Such protective coatings are further described in U.S. Provisional Patent Application No. 62 / 549,082, filed December 16, 2016, entitled "Infrared-Reflecting Optically Transparent Assembly and Method of Making the Same," which is incorporated herein by reference to the extent not inconsistent herewith. The composition can be coated onto the optical film and then cured before forming (e.g., thermoforming) the optical film into a desired shape.

[0038] The prefix "(meth)acrylic" refers to methacryl and / or acrylic. "Urethane (meth)acrylate compound" means a compound having at least one (preferably at least 2, 3, 4 or more) carbamate group (i.e., -NHC(=O)O-) and at least one (meth)acrylic group. By definition, the sum of the weight percents of the components in a composition should not exceed 100 weight percent.

[0039] Exemplary urethane (meth)acrylate compounds having an average (meth)acrylate functionality of 3 to 9 are available from commercial sources and / or can be prepared according to known methods.Commercially available urethane (meth)acrylate compounds include EBECRYL 264 aliphatic urethane triacrylate, EBECRYL 265 aliphatic urethane triacrylate, EBECRYL 1258 aliphatic urethane triacrylate, EBECRYL 4100 aliphatic urethane triacrylate, EBECRYL 4101 aliphatic urethane triacrylate, EBECRYL 8412 aliphatic urethane acrylate (trifunctional), EBECRYL 4654 aliphatic urethane triacrylate, EBECRYL 4666 aliphatic urethane triacrylate, EBECRYL 4738 aliphatic allophanate urethane triacrylate, EBECRYL 4740 aliphatic allophanate urethane triacrylate, EBECRYL 8405 aliphatic urethane tetraacrylate, and EBECRYL 8604 aliphatic urethane tetraacrylate, all manufactured by Allnex (Brussells, Belgium). Aliphatic urethane tetraacrylate, EBECRYL 4500 Aromatic urethane tetraacrylate, EBECRYL 4501 Aromatic urethane tetraacrylate, EBECRYL 4200 Aliphatic urethane tetraacrylate, EBECRYL 4201 Aliphatic urethane tetraacrylate, EBECRYL 8702 Aliphatic urethane hexaacrylate, EBECRYL 220 Aromatic urethane hexaacrylate, EBECRYL 221 Aromatic urethane hexaacrylate, EBECRYL 2221 Aromatic urethane hexaacrylate, EBECRYL 2221 Aromatic urethane hexaacrylate, EBECRYL 5129 Aliphatic urethane hexaacrylate, EBECRYL 1290 Aliphatic urethane hexaacrylate, EBECRYL 1291 Aliphatic urethane hexaacrylate, EBECRYL 8301-R Aliphatic urethane hexaacrylate, EBECRYL 8602 aliphatic urethane acrylate (non-functional); CN929 trifunctional urethane acrylate and CN9006 aliphatic urethane acrylate (hexafunctional) available from Sartomer Co., Exton, Pennsylvania.In some embodiments, the urethane (meth)acrylate compound can be synthesized by reacting a polyisocyanate compound with a hydroxyl-functional (meth)acrylate compound. Various polyisocyanates can be used in preparing the urethane (meth)acrylate compound. As used herein, the term "polyisocyanate" refers to any organic compound having two or more reactive isocyanate (-NCO) groups in a single molecule, such as, for example, diisocyanates, triisocyanates, tetraisocyanates, and mixtures thereof. For improved weather resistance and reduced yellowing, the urethane (meth)acrylate compound used herein is preferably aliphatic and thus derived from an aliphatic polyisocyanate.

[0040] The average (meth)acrylate functionality is calculated in the following manner: First calculate the functionality of the acrylate added for each compound. For example, the composition may include 1.0 equivalent of DESN100 (DESMODUR N100 biuret-based hexamethylene diisocyanate oligomer, 100% solids, 22.0% NCO by weight, 191 g / equivalent, available from Covestro LLC, Pittsburgh, Pennsylvania), 0.25 equivalent of HEA (2-hydroxyethyl acrylate, available from Alfa Aesar, Tewksbury, Massachusetts), and 0.75 equivalent of PET3A (pentaerythritol triacrylate, available from Sartomer Co., Exton, Pennsylvania, as SR444C). This means that the compound is the reaction product of one equivalent of isocyanate group (as DESN100) with 0.25 hydroxyl equivalents of hydroxyethyl acrylate and 0.75 hydroxyl equivalents of PET3A. HEA has one acrylate group per hydroxyl group, and PET3A has three acrylate groups per hydroxyl group. As a result, the added acrylate functionality of this compound is (0.25 x 1) + (0.75 x 3) or 2.5. The average (meth)acrylate functionality is found by multiplying the added acrylate functionality for each compound by the average functionality of the polyisocyanate. According to Covestro, the average functionality of DESN100 is 3.6, so the average (meth)acrylate functionality of this compound is 2.5 x 3.6 or 9. Other estimated average functionalities of the polyisocyanates for DESN3300, DESN3800, and DESZ4470BA are 3.5, 3.0, and 3.3, respectively.

[0041] In some embodiments, a portion of the isocyanate groups of the polyisocyanate can be reacted with a polyol, such as, for example, an alkoxylated polyol available from Perstorp Holding AB (Sweden) as Polyol 4800. Such polyols can have a hydroxyl number of 500 to 1000 mg KOH / g and a molecular weight ranging from at least 200 or 250 g / mole up to 500 g / mole.

[0042] In some embodiments, a portion of the isocyanate groups of the polyisocyanate can be reacted with a polyol, such as 1,6-hexanediol.

[0043] The selection of reaction conditions, and catalyst, if any, used to react the polyisocyanate with the (meth)acrylated alcohol will be apparent to one skilled in the art.

[0044] Useful (meth)acrylate monomers (preferably non-urethane and preferably non-silicone, although this is not required) have a (meth)acrylate functionality of 1 to 2. These monomers can function, for example, as diluents or solvents, viscosity reducers, binders during curing, and crosslinkers. Examples of useful (meth)acrylates include mono(meth)acrylates such as octyl (meth)acrylate, nonylphenol ethoxylate (meth)acrylate, isononyl (meth)acrylate, isobornyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, beta carboxyethyl (meth)acrylate, isobutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, n-butyl (meth)acrylate, methyl (meth)acrylate. , hexyl (meth)acrylate, (meth)acrylic acid, stearyl (meth)acrylate, hydroxy-functional caprolactone ester (meth)acrylate, isooctyl (meth)acrylate, hydroxymethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyisopropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyisobutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, alkoxylated versions of the above (meth)acrylate monomers, such as alkoxylated tetrahydrofurfuryl (meth)acrylate, and combinations thereof. In some embodiments, tetrahydrofurfuryl (meth)acrylate is preferred.Di(meth)acrylates include, for example, 1,6-hexanediol di(meth)acrylate, poly(ethylene glycol) di(meth)acrylate, polybutadiene di(meth)acrylate, polyurethane di(meth)acrylate, ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and alkoxylated versions of the above di(meth)acrylates, and combinations thereof. Of these, 1,6-hexanediol diacrylate is preferred in some embodiments. (Meth)acrylate monomers having a functionality of 1 or 2 (such as those described above) are widely available commercially.

[0045] Exemplary useful silicone (meth)acrylates include monofunctional and multifunctional silicone (meth)acrylates.Of these, silicone poly(meth)acrylates may be preferred, because the silicone (meth)acrylates generally reduce the possibility of unbonding after curing.Exemplary silicone (meth)acrylates include EBECRYL 350 silicone diacrylate and EBECRYL 1360 silicone hexaacrylate from Allnex, CN9800 aliphatic silicone acrylate and CN990 silicone urethane acrylate compound from Sartomer Co., and TEGO RAD 2100, TEGO RAD 2250, and TEGO RAD 2500 silicone polyether acrylate from Evonik Industries (Parsippany, New Jersey).

[0046] The curable composition may optionally, but preferably, further comprise an effective amount of a photoinitiator. The term "effective amount" means an amount that is at least an amount sufficient to cause curing of the curable composition under ambient conditions. It will be recognized that curing may be completed even if polymerizable (meth)acrylate groups remain.

[0047] Exemplary photoinitiators include α-cleavage photoinitiators such as benzoin and its derivatives, e.g., α-methylbenzoin; α-phenylbenzoin; α-allylbenzoin; α-benzylbenzoin; benzoin ethers, e.g., benzil dimethyl ketal (available as IRGACURE 651 from Ciba Specialty Chemicals, Tarrytown, New York), benzoin methyl ether, benzoin ethyl ether, benzoin n-butyl ether; acetophenone and its derivatives, e.g., 2-hydroxy-2-methyl-1-phenyl-1-propanone (available as DAROCUR 1173 from Ciba Specialty Chemicals) and 1-hydroxycyclohexyl phenyl ketone (available as IRGACURE 184 from Ciba Specialty Chemicals); 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone (available as IRGACURE 184 from Ciba Specialty Chemicals), and the like. 907); 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone (available as IRGACURE 369 from Ciba Specialty Chemicals); titanium complexes such as bis(η5-2,4-cyclopentadiene-1-yl)bis[2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl]titanium (available as CGI 784 DC from Ciba Specialty Chemicals); and mono- and bisacylphosphines (available as IRGACURE 1700, IRGACURE 1800, IRGACURE 1850, and DAROCUR 4265 from Ciba Specialty Chemicals). One useful photoinitiator, a bifunctional α-hydroxyketone, is available as ESACURE ONE from LAMBERTI SpA (Albizzate, Italy).

[0048] 4C shows an alternative embodiment in which the optical stack 420c includes a first layer 430c and a second layer 430b in addition to the optical film 422. The first layer 430c extends beyond the periphery 425 of the optical film 422, but the second layer 430b does not. In some embodiments, the second layer 430b is a protective layer (e.g., a hard coat) and the first layer 430c is a liner.

[0049] In some embodiments, the optical stack includes an optical film having an interface between a first major surface of the liner and an outermost major surface of the optical film. The interface may be optically smooth or textured. In some applications, it may be desirable for the interface to be optically smooth (e.g., to provide a specular reflection), while in other applications it may be desirable for it to be non-smooth (e.g., to add some diffusing properties to an otherwise specular reflection). FIG. 4D is a schematic cross-sectional view of an optical stack 420d including a liner 430d, an optical film 422d, and a textured interface 428d therebetween. The optical film often starts with an optically smooth surface, but the surface can be textured in subsequent film processing. The interface may be textured, for example, by the forming process. In some embodiments, the optical film may be formed into a desired shape, for example, in a thermoforming process, and the texture from the mold used in the thermoforming process may be imparted to the outer surface of the optical film that is then covered by the liner. The texture in the mold may be designed into the mold or may be an artifact of how the mold was made, for example. In other embodiments, a liner (which may or may not be the same liner used in the subsequent insert molding process) is applied to the optical film prior to thermoforming and any texture from the mold is not imparted to the optical film.

[0050] 5A is a schematic cross-sectional view of an optical assembly 500 including a lens having opposing first and second major surfaces 515 and 517, and an optical stack 520 disposed on the lens 510. The first major surface 515 includes a first portion 512 and a second portion 514. The optical stack includes an optical film 522 and an optional additional film or layer 530. The additional layer 530 may also be referred to as a first layer. More than one additional layer 530 may be included. For example, the additional layer may include a first layer disposed on the optical film 522 and a second layer disposed on the first layer opposite the lens 510 (e.g., the first layer may be a hard coat and the second layer may be a liner). The optical film 522, which may be a multilayer optical film as further described elsewhere herein, has a first major surface 527 and a second major surface 529. A first major surface 527 of the optical film 522 is disposed on a first portion 512 of the first major surface 515 of the lens 510. The optical film 522 is disposed between the lens 510 and an additional layer 530, which may be, for example, a liner or a protective layer. In some embodiments, the optical film 522 is an integrally formed multilayer optical film and the additional layer 530 is not integral with the optical film 522.

[0051] The second major surface 529 is substantially coplanar with the second portion 514 of the first major surface 515. A major surface of a film or layer can be described as being substantially coplanar with another surface (or other surface that is substantially coplanar with the major surface of the film or layer) if the separation between the major surface and the other surface is about 30% or less of the thickness of the film or layer. In some embodiments, the separation between the major surface of the film or layer and the other surface is 20% or less, or 10% or less of the thickness of the film or layer.

[0052] The second portion 514 of the first major surface 515 may extend perpendicularly from the first portion 512 of the first major surface 515, as shown generally in Figure 5A, or the second portion 514 may extend at an angle from the first portion 512. The precise angle can be determined by the shape of the edge of the optical film 522 when the lens is insert molded onto the optical stack 520. The shape of the edge can depend on how the optical film 522 was cut from a larger film (e.g., a roll of optical film).

[0053] In some embodiments, the additional layer 530 is not included. In some embodiments, the optical assembly 500 is formed with the additional layer 530 being a liner that is subsequently removed. Figure 5B is a schematic diagram of an optical assembly 500b that can be formed, for example, by removing the additional layer 530 from the optical assembly 500.

[0054] Figure 5C is a schematic cross-sectional view of lens 510 without an optical film(s) disposed on first major surface 515, and Figure 5D is a schematic top view of lens 510. First major surface 515 may be described as defining a curved recess 519. In the illustrated embodiment, curved recess 519 extends above first portion 512 of first major surface 515 and is bounded by second portion 514 of first major surface 515.

[0055] 5A, the lens 510 can be described as at least partially wrapping around the edge of the optical stack 520. The edge of the optical stack 520 includes the edge 551a of the optical film 522 and the edge 551b of the additional layer 530. In the illustrated embodiment, the lens 510 wraps at least partially around the edge 551a of the optical film 522 portion of the optical stack 520 to be flush with the optical film 522. Other optical elements, such as prisms, for example, may be molded on the optical film and may at least partially wrap around the edge of the optical film and may optionally be flush with the optical film.

[0056] In other embodiments, the lens may also at least partially wrap around the edges of the additional layer. FIG. 6A is a schematic cross-sectional view of an optical assembly 600 including an optical stack 620 disposed on a first portion 612 of a first major surface 615 of a lens 610. The lens 610 has a second major surface 617 opposite the first major surface 615. The optical stack 620 includes a multilayer optical film 622 and an additional layer or film 630 disposed on the multilayer optical film 622. The lens 610 at least partially wraps around the edges of the optical stack 620. In the illustrated embodiment, the lens 610 wraps around the edges of the optical film 622 and at least partially wraps around the edges of the additional film 630. In some embodiments, the lens 610 wraps around the edges of the additional film 630 at least partially to be flush with the additional film 630. For example, the outermost major surface of the additional film 630 opposite the first portion 612 may be flush with the second portion 614 of the first major surface 615 .

[0057] The multilayer optical film 622 includes a first major surface 627 disposed on the first portion 612 and includes an opposing second major surface 629. In some embodiments, the lens wraps completely around the edges of the multilayer optical film 622 and extends in a direction parallel to the normal 653 to the lens 610, beyond the second major surface 629 of the multilayer optical film 622, to the center of the first major surface 615 of the lens 610.

[0058] In some embodiments, the additional film 630 is a protective film (e.g., a hard coat). In some embodiments, the additional film 630 is a peelably attached liner. Figure 6B is a schematic cross-sectional view of optical assembly 600b, which corresponds to optical assembly 600 except that additional layer 630 has been removed.

[0059] In some embodiments, the lens has a first major surface that defines a curved recess therein, and the multilayer optical film is adhered and conforms to the curved recess. For example, any of the embodiments shown in Figures 5A-5B and 6A-6B can be described as having an optical film that conforms to the curved recess defined by the first major surface. The optical film can be adhered to the curved recess, for example, by being diffusion bonded to the lens via a diffusion bond, as further described elsewhere herein. Alternatively, the lens can be formed separately, and the optical film can be bonded to the curved recess, for example, with an optionally optically clear adhesive.

[0060] In some embodiments, the optical film disposed on the optical element is convex toward the optical element. In some embodiments, the optical film disposed on the optical element is concave toward the optical element. In some embodiments, the optical film is adhesively conforming to a convex surface (e.g., a convex surface of a curved concave). In some embodiments, the optical film is adhesively conforming to a concave surface (e.g., a concave surface of a curved concave). In some embodiments, the optical film is adhesively conforming to a flat surface.

[0061] 7A-7C show a schematic of a method for making an optical assembly. The method includes providing a first mold 460 having a first curved mold surface 462 (FIG. 7A) and placing a molded optical film or optical stack 720 on the first curved mold surface 462 (FIGS. 7B-7C). The optical stack is preferably formed (e.g., by thermoforming) into a desired shape that substantially matches the shape of the first curved mold surface 462. Thermoforming of the film or optical stack can be performed by heating the film or optical stack and contacting the optical stack with a curved mold while stretching the optical stack, as generally described, for example, by U.S. Pat. Nos. 9,557,568 (Ouderkirk et al.) and 6,788,463 (Merrill et al.). Next, the second mold 470 is positioned such that the second mold surface 472 of the second mold 470 is aligned with and spaced apart from the first curved mold surface 462. The second mold surface 472 may be curved as shown, or may be substantially planar. The first mold surface 462 and the second mold surface 472 define a mold cavity 480 therebetween (FIG. 7B). The mold cavity 480 is then filled or substantially filled with a flowable material 483 (FIG. 7C) and then solidified to form a solid optical element bonded to the optical stack 720 (see, e.g., optical element 110 of optical assembly 100). The flowable material 483 may be introduced into the mold cavity 480 through gate 481. The first mold 460 and the second mold 470 may be removed and excess material (e.g., runner material from gate 481) may be removed. Substantially filling the mold cavity may be understood to mean filling the mold cavity by more than 50 volume percent. In some embodiments, the mold cavity is filled to at least 80 volume percent, or at least 90 volume percent, or at least 95 volume percent. In some embodiments, the mold cavity 480 is completely filled with the flowable material 483, except for the volume occupied by the optical stack 720.

[0062] In some embodiments, when the flowable material 483 flows into the cavity 480, the flowable material 483 has a temperature higher than the glass transition temperature of the optical stack 720. In some embodiments, the first mold 460 and the second mold 470 are held at a temperature lower than the melting point of the flowable material 483 to solidify the flowable material 483. In some embodiments, when the flowable material 483 flows into the cavity 480, the temperature of the first mold 460 and the second mold 470 is also lower than the glass transition temperature of the optical stack 720. For example, the flowable material 483 may have a temperature in the range of 250-300°C when introduced into the cavity 480, the first and second molds may have a temperature in the range of 75-100°C, and the optical stack 720 may have a glass transition temperature in the range of 105-130°C. In some embodiments, the optical stack 720 has multiple layers and the flowable material 483 has a temperature greater than the glass transition temperature of each layer of the optical stack 720 when the flowable material 483 flows into the cavity 480. In some embodiments, the optical stack 720 has multiple layers and the flowable material 483 has a temperature greater than the glass transition temperature of at least one layer of the optical stack 720 when the flowable material 483 flows into the cavity 480. In some embodiments, the optical stack 720 has multiple layers and the flowable material 483 has a temperature greater than the glass transition temperature of the layer of the optical stack 720 that is immediately adjacent to the flowable material 483 when the flowable material 483 flows into the cavity 480 and contacts the optical stack 720. This layer may be, for example, a skin layer of an integrally formed optical film included in the optical stack 720. In some embodiments, the optical stack 720 includes multiple layers including a birefringent polymer layer, and the flowable material 483 has a temperature higher than the glass transition temperature of the birefringent polymer layer when the flowable material 483 flows into the cavity 480.

[0063] In some embodiments, the melting temperature of the formed optical element is substantially higher than the glass transition temperature of the optical film or optical laminate (the glass transition temperature can be any of the glass transition temperatures mentioned above). Substantially higher refers to a temperature greater than 10° C., unless otherwise indicated. In some embodiments, the melting temperature of the optical element is at least about 50° C. higher, or at least about 80° C. higher, than the glass transition temperature of the optical film. In some embodiments, the absolute value of the difference between the melting temperature of the optical element and the melting temperature of the optical film is less than about 50° C., or less than about 30° C., or less than about 20° C., or less than about 10° C. In some embodiments, the melting temperature of the optical element is about the same as the melting temperature of the optical film. About the same refers to a temperature difference of less than 10° C., unless otherwise indicated. The melting temperature of the optical film can be the melting temperature of any of the layers described for the glass transition temperature. For example, the melting temperature can be that of the layer of the optical film directly adjacent to the flowable material 483 when the flowable material 483 flows into the cavity 480 and contacts the optical film.

[0064] In some embodiments, the optical stack 720 includes a liner as described elsewhere herein. In some embodiments, the liner has a glass transition temperature greater than about 50° C. or greater than about 80° C.

[0065] The glass transition temperatures of the various films or layers can be determined by differential scanning calorimetry as described in test standard ASTM E1356-08(2014) "Standard Test Method for Assignment of the Glass Transition Temperatures by Differential Scanning Calorimetry."

[0066] In some embodiments, the first mold 460 is a first mold insert configured to be placed within a mold base. Similarly, in some embodiments, the second mold 470 is a second mold insert configured to be placed within a mold base.

[0067] The first curved mold surface 462 has a best fit spherical first radius of curvature R, which in some embodiments is in the range of about 30 mm to about 1000 mm. The first curved mold surface 462 has a sag S. In some embodiments, the ratio of the sag S to the best fit spherical first radius of curvature R is in the range of about 0.02 to about 0.2, or in the range of about 0.02 to about 0.15, or in the range of about 0.02 to about 0.12, or in the range of about 0.03 to about 0.12, or in the range of about 0.04 to about 0.12. In some embodiments, the optical stack 720 has a sag to radius ratio in any of these ranges.

[0068] 7D is a schematic cross-sectional view of an alternative optical stack 720d disposed on the first curved mold surface 462 of the first mold 460. In this case, the optical stack 720d does not extend to the edge of the first curved mold surface 462. The optical assembly resulting from injection molding of a lens onto the optical stack 720d can be, for example, as described for the optical assembly 600.

[0069] 7E is a schematic cross-sectional view of an alternative optical stack 720e disposed on the first curved mold surface 462 of the first mold 460. In this case, the optical stack 720e includes an optical film 722e that does not extend to the edge of the first curved mold surface 462, and an additional layer 730e (e.g., a liner releasably attached to the optical film 722e). The optical assembly resulting from injection molding of a lens onto the optical stack 720e can be, for example, as described for the optical assembly 500.

[0070] The insert molding process can be repeated using the first optical element injection molded onto the optical film as an insert for a second insert molding process to form a second optical element on the optical film opposite the first optical element.

[0071] 8A is a schematic cross-sectional view of an optical assembly 800 including an optical stack or optical film 820, a first optical element 810a that may be injection insert molded directly onto the optical film 820, and a second optical element 810b disposed on the optical film 820 opposite the first optical element 810a. The second optical element 810b may be injection insert molded directly onto the optical film 820 opposite the first optical element 810a. In some embodiments, the first optical element 810a and the second optical element 810b are first and second lenses. In some embodiments, each location on each of the first and second lenses has an optical retardance of about 10 nm or less.

[0072] In some embodiments, a lens having the shape of the second optical element 810b is molded onto the optical film 820 without including the first optical element 810a. Figure 8B is a schematic cross-sectional view of an optical assembly 800b including an optical film 820 and an optical element 810b that can be injection insert molded directly onto the optical film 820.

[0073] Another embodiment is shown in Figure 8C, which is a schematic cross-sectional view of an optical assembly 800c including an optical stack or film 820c and an optical element 810c insert molded onto the optical stack or film 820c, where the optical stack or film 820c is disposed on a substantially flat surface of the optical element 810c.

[0074] The optical retardance at a location on an optical element, such as a lens, is the phase retardance of light transmitted through the optical element that passes through that location and has the shortest path through the optical element. For example, FIG. 9 shows two rays 988 and 989 that are incident on an optical element 910 at location 987 and transmitted through the optical element 910. The optical retardance is specified for ray 989 because ray 989 has the shortest path through the optical element 910 for rays that pass through location 987. If the opposing major surfaces of the optical element 910 are approximately parallel, then approximately normally incident light has the shortest path through the optical element. If the opposing major surfaces are not parallel, the shortest path may be for non-normally incident light. The phase retardance is the maximum difference in phase for two orthogonally polarized rays that pass through that location. The wavelength of the incident light is approximately 550 nm unless otherwise indicated. The optical retardance of an optical element can be characterized by its location on the major surfaces of the optical element. In some embodiments, the optical element, such as a lens, has low optical retardance. In some embodiments, the optical retardance is about 10 nm or less at each location across at least 80% or at least 90% of the major surface (surface area) of the optical element. In some embodiments, the optical retardance at each location on the optical element is about 10 nm or less, or about 7 nm or less. In some embodiments, the optical element is a lens with an optical retardance of about 5 nm or less at the center of the lens.

[0075] In some embodiments, the optical retardance is low (e.g., in any of the ranges described above) even if the lens has substantial thickness variation. For example, in some embodiments, the lens has an optical retardance of about 10 nm or less at each position over at least 80% of the major surface of the lens, and has a lens thickness at a first lens position that is at least about 20% greater, or at least about 30% greater, or at least about 40% greater, or at least about 50% greater, or at least about 75% greater, or at least about 100% greater, or at least about 150% greater, or at least about 200% greater than the lens thickness at a second lens position.

[0076] The optical retardance of the optical element can be made low (e.g., less than 10 nm) by using a low retardance material as the flowable material 483 in making the optical element and / or by maintaining the flowable material 483 at an elevated temperature after filling the mold cavity 480 with the flowable material 483 for a sufficient time for the birefringence to substantially relax. Suitable materials that can be used for the flowable material 483 include polymethylmethacrylate (PMMA), polycarbonate, polystyrene, cyclic olefins, and polyethylene terephthalate (PET). A suitable PMMA that provides low birefringence is, for example, Optimas 7500 available from Mitsubishi Gas Chemical Company, Inc. It has been found that an optical film having multiple alternating polymer layers can still provide high reflectivity for at least one polarization state when the lens or optical element has a melting point higher than the glass transition temperature of the optical film but lower than the melting temperature of the optical film, even when the optical element is allowed to relax to low birefringence.

[0077] Even when the birefringence can be relaxed to a lower value, residual birefringence and optical retardance may still be present, but the optical retardance may be low (e.g., 10 nm or less). In some embodiments, the optical retardance remains about 10 nm or less while showing some spatial variation through the optical element. In some embodiments, the optical retardance of the optical element, which may be a lens, exceeds the optical retardance of the optical element at at least one location closer to the edge of the optical element and at least one location closer to the center of the optical element.

[0078] FIG. 10 is a schematic top view of a lens 1010 having a maximum lateral dimension along a first direction (parallel to the x-direction) of D1 and a maximum lateral dimension along an orthogonal second direction (parallel to the y-direction) of D2. D1 may be larger, smaller, or approximately the same as D2. In some embodiments, the lens 1010 has an optical retardance that varies less along the maximum lateral dimension in the orthogonal second direction D2 and more along the maximum lateral dimension in the first direction D1 that is about 10 nm or less at each location on the lens 1010. In some cases, the variation in optical retardance is due to the injection insert molding process used to create the lens 1010, where the optical retardance is higher near the gate and lower than other locations. For example, a first edge location 1094 may be an edge location near the gate and may have a higher optical retardance than a center location 1095. In some embodiments, the first edge position 1094 has an optical retardance higher than the optical retardance at the center position 1095 and higher than the optical retardance at the second edge position 1096. In some embodiments, the third edge position 1097 and the fourth edge position 1098 have an optical retardance within R1 of the optical retardance at the center position 1095, and the first edge position 1094 has an optical retardance greater than R2 plus the optical retardance at the center position 1095 (where R2>R1). For example, R2 may be 2.5 nm, R1 may be 1.5 nm, the optical retardance at the center position 1095 may be 4 nm, the optical retardance at each of the second edge position 1096, the third edge position 1097, and the fourth edge position 1098 may each be about 5 nm, and the optical retardance at the first edge position 1094 may be about 7 nm. In some embodiments, the highest optical retardance occurs at the first edge position 1094 (near the gate) and the lowest optical retardance occurs at the center position 1095.

[0079] The edge and center locations refer to locations near the edge or center, respectively, of the lens 1010. The center of the lens 1010 may refer to the center in a plan view where the first and second directions intersect. In some embodiments, the center location is within 10% of the lesser of D1 and D2 of the center of the lens 10, and the edge location is within 10% of the lesser of D1 and D2 of the edge of the lens 10.

[0080] In some embodiments, the lens 1010 is molded on an optical film or an optical stack including optical films, the optical film being a reflective polarizer, where each location on the reflective polarizer substantially reflects normally incident light having a predetermined wavelength and a block polarization state and substantially transmits normally incident light having a predetermined wavelength and an orthogonal pass polarization state. In some embodiments, the first direction is substantially parallel to the block polarization state at the center of the reflective polarizer. In some embodiments, the first direction is substantially parallel to the pass polarization state at the center of the reflective polarizer. In some embodiments, the first direction is at an oblique angle to the block polarization state at the center of the reflective polarizer. For example, the block axis of the reflective polarizer at the center of the reflective polarizer may be along an axis 1099 that makes an angle α with the first direction along D1. In some embodiments, the angle α is less than 10 degrees.

[0081] Terms such as "about" or "substantially" will be understood by those of skill in the art in the context in which they are used and described in the present description. If the use of "about" as applied to quantities describing feature shapes, quantities, and physical properties is not clear to those of skill in the art in the context in which they are used and described in the present description, "about" will be understood to mean within 10 percent of a particular value. A quantity given as about or approximately a particular value may be exactly that particular value. For example, if it is not clear to those of skill in the art in the context in which they are used and described in the present description, a quantity having a value of about 1 means a quantity having a value between 0.9 and 1.1 and the value may be 1.

[0082] Below is a list of exemplary embodiments of the present specification.

[0083] Embodiment 1 is an optical assembly including an optical element insert molded directly onto an optical laminate, the optical laminate including an optical film and a liner, the optical film being disposed between the optical element and the liner; The liner is removable from the optical film without substantially damaging the optical film.

[0084] Embodiment 2 is the optical assembly of embodiment 1, wherein each location over at least about 80% of the total area of ​​the optical film has a reflectivity of greater than about 80% for normally incident light having the same predetermined wavelength and the same first polarization state.

[0085] Embodiment 3 is the optical assembly of embodiment 2, wherein each location over at least about 80% of the total area of ​​the optical film has a reflectivity of greater than about 80% for normally incident light having a given wavelength and a same second polarization state that is orthogonal to the first polarization state.

[0086] Embodiment 4 is the optical assembly of embodiment 2, wherein each location over at least about 80% of the total area of ​​the optical film has a transmission of greater than about 80% for normally incident light having a given wavelength and a same second polarization state that is orthogonal to the first polarization state.

[0087] Embodiment 5 is the optical assembly of embodiment 2, wherein each location over at least about 80% of the total area of ​​the optical film has a transmission of less than about 5% for normally incident light having a given wavelength and a first polarization state.

[0088] Example 6 is the optical assembly of any one of Examples 1-5, wherein the optical film includes a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference.

[0089] Embodiment 7 is the optical assembly of embodiment 1, in which the optical element is injection insert molded directly onto the optical stack.

[0090] Embodiment 8 is the optical assembly of embodiment 7, wherein the melting temperature of the optical element is substantially higher than the glass transition temperature of the optical film.

[0091] Example 9 is the optical assembly of Example 7, wherein the melting temperature of the optical element is about the same as the melting temperature of the optical film.

[0092] Embodiment 10 is the optical assembly of embodiment 1, wherein the liner has a glass transition temperature greater than about 50°C.

[0093] Embodiment 11 is the optical assembly of embodiment 1, wherein the liner completely covers the optical film and extends beyond the periphery of the optical film.

[0094] A twelfth embodiment is the optical assembly of any one of the first to eleventh embodiments, wherein the optical element is a lens.

[0095] Embodiment 13 is the optical assembly of any one of Embodiments 1-12, wherein the optical element has an optical retardance of about 10 nm or less at each location on the optical element.

[0096] Embodiment 14 is an optical assembly of any one of embodiments 1 to 13, wherein the optical retardance of the optical element at at least one position closer to the edge of the optical element exceeds the optical retardance of the optical element at at least one position closer to the center of the optical element.

[0097] Embodiment 15 is the optical assembly of embodiment 1, wherein the interface between the first major surface of the liner and the outermost major surface of the optical film is optically smooth.

[0098] Embodiment 16 is the optical assembly of embodiment 1, wherein the interface between the first major surface of the liner and the outermost major surface of the optical film is textured.

[0099] Embodiment 17 is the optical assembly of embodiment 1, wherein a protective coating is disposed on the optical film between the optical film and the liner.

[0100] Embodiment 18 is the optical assembly of embodiment 1, wherein the optical film includes a plurality of interference layers and an outermost non-interference layer.

[0101] Embodiment 19 is the optical assembly of embodiment 18, wherein the outermost non-interference layer includes a protective coating.

[0102] Embodiment 20 is the optical assembly of embodiment 17 or 19, wherein the protective coating is a hard coat.

[0103] Embodiment 21 is a method for preparing a protective coating comprising: a) 70 to 90 weight percent, based on the total weight of components a) to d), of a urethane (meth)acrylate compound having an average (meth)acrylate functionality of 3 to 9; b) 5 to 20% by weight, based on the total weight of components a) to d), of a (meth)acrylate monomer having a (meth)acrylate functionality of 1 to 2, which is not a urethane (meth)acrylate compound; c) 0.5 to 2 wt. % of a silicone (meth)acrylate, based on the total weight of components a) to d); and d) an optional effective amount of a photoinitiator.

[0104] Embodiment 22 is the optical assembly of embodiment 1, wherein the optical element at least partially wraps around an edge of the optical stack.

[0105] Embodiment 23 is the optical assembly of embodiment 1, wherein the optical element at least partially wraps around an edge of the optical film so as to be substantially flush with the optical film.

[0106] Embodiment 24 is an integrally formed multilayer optical film; a first optical element injection insert molded directly onto the optical film, the optical film comprising a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference, each location over at least 80% of the total area of ​​the optical film having a reflectivity of greater than about 80% for normally incident light having the same predetermined wavelength and the same first polarization state; The optical assembly, wherein the melting temperature of the first optical element is substantially higher than the glass transition temperature of the optical film.

[0107] Embodiment 25 is the optical assembly of embodiment 24, wherein the melting temperature of the first optical element is at least about 50° C. higher than the glass transition temperature of the optical film.

[0108] Embodiment 26 is the optical assembly of embodiment 24 integrally formed.

[0109] Embodiment 27 is the optical assembly of embodiment 24, wherein the outermost layer of the optical film is diffusion bonded to a major surface of the first optical element.

[0110] Embodiment 28 is the optical assembly of embodiment 27, wherein the bond of the optical film to the optical element is stronger than an interlayer bond between at least one pair of immediately adjacent layers in the optical film.

[0111] Embodiment 29 is the optical assembly of embodiment 24, wherein the first optical element is a lens.

[0112] Embodiment 30 is the optical assembly of embodiment 24, wherein the absolute value of the difference between the melting temperature of the first optical element and the melting temperature of the optical film is less than 50°C.

[0113] Embodiment 31 is an optical assembly of embodiment 24, in which the first optical element has an optical retardance that varies more along its maximum lateral dimension in a first direction and less along its maximum lateral dimension in an orthogonal second direction.

[0114] Embodiment 32 is the optical assembly of embodiment 31, wherein the optical film is a reflective polarizer, each location on the reflective polarizer substantially reflects normally incident light having a predetermined wavelength and a block polarization state and substantially transmits normally incident light having a predetermined wavelength and an orthogonal pass polarization state, and the first direction is substantially parallel to the block polarization state at the center of the reflective polarizer.

[0115] Embodiment 33 is an integrally formed multilayer optical film, the optical film including a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference; an optical element insert molded directly onto the optical film, the optical film being diffusion bonded to the optical element; The bond of the optical film to the optical element is an optical assembly that is stronger than the interlayer bonds between at least one pair of immediately adjacent layers in the optical film.

[0116] Embodiment 34 is the optical assembly of embodiment 33, wherein each location on the optical film has a reflectivity of greater than about 80% for normally incident light having the same predetermined wavelength and the same first polarization state.

[0117] Embodiment 35 is the optical assembly of embodiment 34, wherein each location on the optical film has a reflectivity of greater than about 80% for normally incident light having a given wavelength and the same second polarization state that is orthogonal to the first polarization state.

[0118] Embodiment 36 is the optical assembly of embodiment 34, wherein each location on the optical film has a transmission of greater than about 80% for normally incident light having a given wavelength and the same second polarization state that is orthogonal to the first polarization state.

[0119] Embodiment 37 is the optical assembly of embodiment 33, wherein the optical element is injection insert molded directly onto the optical film, and the melting temperature of the first optical element is at least about 50° C. higher than the glass transition temperature of the optical film.

[0120] Embodiment 38 is an integrally formed multilayer optical film, the optical film including a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference, each location over at least 90% of a total area of ​​the optical film having a reflectivity of greater than about 90% for normally incident light having the same predetermined wavelength and the same first polarization state; an optical element insert molded directly onto the optical film, the optical film being diffusion bonded to the optical element.

[0121] Embodiment 39 is the optical assembly of embodiment 38, wherein the melting temperature of the optical element is substantially higher than the glass transition temperature of the optical film.

[0122] Embodiment 40 is the optical assembly of embodiment 38, wherein the melting temperature of the optical element is at least about 50° C. higher than the glass transition temperature of the optical film.

[0123] Embodiment 41 is the optical assembly of embodiment 38, wherein the absolute value of the difference between the melting temperature of the first optical element and the melting temperature of the optical film is less than about 50°C.

[0124] Embodiment 42 is the optical assembly of embodiment 38, wherein the bond of the optical film to the optical element is stronger than an interlayer bond between at least one pair of immediately adjacent layers in the optical film.

[0125] Embodiment 43 is the optical assembly of embodiment 38, wherein the optical film is a reflective polarizer, each location on the reflective polarizer substantially reflects normally incident light having a predetermined wavelength and a block polarization state and substantially transmits normally incident light having a predetermined wavelength and an orthogonal pass polarization state, the first polarization state being the block polarization state at the center of the reflective polarizer.

[0126] Embodiment 44 is the optical assembly of embodiment 43, wherein each location on the optical film has a transmission of less than about 1% for normally incident light having a predetermined wavelength and block polarization state.

[0127] Embodiment 45 is An optical assembly comprising: an optical film including multiple alternating polymer layers that reflect or transmit light primarily by optical interference, wherein each location over at least 90% of the total area of ​​the optical film has a reflectivity greater than 90% for normally incident light having the same predetermined wavelength and the same first polarization state; and a lens insert molded directly onto the optical film, wherein the lens has an optical retardance that varies more along its largest lateral dimension in a first direction and less along its largest lateral dimension in an orthogonal second direction, wherein the optical retardance at each location on the lens is about 10 nm or less.

[0128] Example 46 is the optical assembly of Example 45, wherein the optical film is a reflective polarizer, and each location on the reflective polarizer substantially reflects normally incident light having a predetermined wavelength and a block polarization state and substantially transmits normally incident light having a predetermined wavelength and an orthogonal pass polarization state.

[0129] Embodiment 47 is the optical assembly of embodiment 45, wherein each location on the optical film has a transmission of less than about 5% for normally incident light having a given wavelength and a first polarization state.

[0130] Embodiment 48 is the optical assembly of embodiment 45, wherein the lens at least partially wraps around an edge of the optical film so as to be substantially flush with the optical film.

[0131] Embodiment 49 is the optical assembly of embodiment 45, in which the optical film is diffusion bonded to the lens such that the bond of the optical film to the optical element is stronger than the interlayer bond between at least one pair of directly adjacent layers in the optical film.

[0132] Embodiment 50 is Lenses and a multilayer optical film having opposing first and second major surfaces, the first major surface disposed on a first portion of the first side of the lens, and each location over at least 80% of a total area of ​​the multilayer optical film has a reflectivity of greater than about 80% for normally incident light having the same predetermined wavelength and the same first polarization state; A second portion of the first side of the lens is substantially coplanar with the second major surface of the multilayer optical film, an optical assembly.

[0133] Embodiment 51 is the optical assembly of embodiment 50, wherein the lens is injection molded directly onto the multilayer optical film.

[0134] Embodiment 52 is the optical assembly of embodiment 50, wherein the lens is injection molded directly onto the optical stack that includes the multilayer optical film.

[0135] Embodiment 53 is an optical assembly of embodiment 52, wherein the optical stack further comprises a first layer that is not integral with the multilayer optical film, and the multilayer optical film is disposed between the lens and the first layer.

[0136] Embodiment 54 is the optical assembly of embodiment 53, wherein the first layer extends across the optical film and a second portion of the first side of the lens.

[0137] Embodiment 55 is the optical assembly of embodiment 53 or 54, wherein the first layer is a protective layer.

[0138] Embodiment 56 is an embodiment in which the protective layer comprises an at least partially cured composition, the composition comprising: a) 70 to 90 weight percent, based on the total weight of components a) to d), of a urethane (meth)acrylate compound having an average (meth)acrylate functionality of 3 to 9; b) 5 to 20% by weight, based on the total weight of components a) to d), of a (meth)acrylate monomer having a (meth)acrylate functionality of 1 to 2, which is not a urethane (meth)acrylate compound; c) 0.5 to 2 wt. % of a silicone (meth)acrylate, based on the total weight of components a) to d); and d) optionally an effective amount of a photoinitiator.

[0139] Embodiment 57 is the optical assembly of embodiment 53 or 54, wherein the first layer is a liner releasably attached to the multilayer optical film.

[0140] Embodiment 58 is the optical assembly of embodiment 50, wherein the second portion of the first side of the lens substantially surrounds a periphery of the first portion of the first side of the lens.

[0141] Embodiment 59 is the optical assembly of embodiment 50, wherein the optical film is diffusion bonded to the lens such that the bond of the optical film to the lens is stronger than the interlayer bond between at least one pair of immediately adjacent layers of the optical film.

[0142] Embodiment 60 is Lenses and an optical stack disposed on a major surface of the lens; The lens is an optical assembly that at least partially wraps around the edge of the optical stack.

[0143] Embodiment 61 is the optical assembly of embodiment 60, wherein the optical stack comprises a multilayer optical film including a plurality of alternating polymer layers that reflect or transmit light primarily by optical interference.

[0144] Embodiment 62 is the optical assembly of embodiment 61, wherein the lens is at least partially wrapped around an edge of the multilayer optical film.

[0145] Embodiment 63 is the optical assembly of embodiment 62, wherein the lens is flush with the multilayer optical film, at least partially wrapped around an edge of the multilayer optical film.

[0146] Embodiment 64 is the optical assembly of embodiment 61, wherein the optical stack further comprises an additional film not integral with the multilayer optical film.

[0147] Embodiment 65 is the optical assembly of embodiment 64, wherein the multilayer optical film is disposed between the additional film and the lens.

[0148] Embodiment 66 is the optical assembly of embodiment 64 or 65, wherein the lens does not wrap around the edge of the additional film.

[0149] Embodiment 67 is the optical assembly of embodiment 64 or 65, wherein the lens at least partially wraps around the edge of the additional film.

[0150] Embodiment 68 is the optical assembly of embodiment 64 or 65, wherein the lens wraps at least partially around an edge of the additional film to be flush with the additional film.

[0151] Embodiment 69 is a lens having a first major surface defining a curved recess therein; and a multilayer optical film that adheres and conforms to the curved recess.

[0152] Embodiment 70 is the optical assembly of embodiment 69, in which the multilayer optical film includes opposing outermost first and second major surfaces, the first major surface of the multilayer optical film is adhered to the curved recess, and a portion of the first major surface of the lens is flush with the second major surface of the multilayer optical film.

[0153] Embodiment 71 is an optical assembly of embodiment 69, in which the multilayer optical film includes opposing outermost first and second major surfaces, the first major surface of the multilayer optical film is adhered to the curved recess, and a portion of the first major surface of the lens wraps around the edge of the multilayer optical film and extends beyond the second major surface of the multilayer optical film in a direction parallel to the normal to the lens to the center of the first major surface of the lens.

[0154] Embodiment 72 is the optical assembly of embodiment 71, further comprising an additional layer disposed on the multilayer optical film opposite the lens, wherein the additional layer is not integral with the multilayer optical film, and a portion of the first main surface of the lens is flush with the outermost main surface of the additional layer opposite the multilayer optical film.

[0155] Embodiment 73 is the optical assembly of embodiment 69, wherein the optical film is diffusion bonded to the lens such that the bond of the optical film to the lens is stronger than an interlayer bond between at least one pair of immediately adjacent layers of the optical film.

[0156] Embodiment 74 is the optical assembly of embodiment 69, wherein each location over at least 80% of the total area of ​​the multilayer optical film has a reflectivity of greater than about 80% for normally incident light having the same predetermined wavelength and the same first polarization state.

[0157] Embodiment 75 is an optical film, wherein each location over at least 80% of a total area of ​​the optical film has a reflectivity of greater than about 80% for normally incident light having the same predetermined wavelength and the same first polarization state; and a lens injection molded directly onto the optical film, the lens having an optical retardance of about 10 nm or less at each position across at least 80% of a major surface of the lens, the lens thickness at a first lens position being at least about 20% greater than the lens thickness at a second lens position.

[0158] Embodiment 76 is the optical assembly of embodiment 75, wherein the optical film includes a plurality of alternating polymer layers, and the optical film is diffusion bonded to the lens such that the bond of the optical film to the lens is stronger than the interlayer bond between at least one pair of immediately adjacent layers in the plurality of alternating polymer layers. EXAMPLES

[0159] Example 1: Insert molding of lenses onto APF Multilayer optical film reflective polarizers (Advanced Polarizing film (APF) available from 3M Company, St. Paul, Minn.) were thermoformed into an 8 base lens shape as generally described in U.S. Pat. No. 9,557,568 (Ouderkirk et al.).

[0160] Optical film insert molding was performed on a Krauss Maffei 65 ton injection molding machine using an 8 base lens blank injection mold. The thermoformed optical film was trimmed to the exact size to fit the injection molding tool and then placed on the convex side of the mold tool. The injection molding process was then performed using PMMA molding material (Optimas 7500, Mitsubishi Gas Chemical Company, Inc.), which was injected at a temperature of 276°C into the mold tool cavity at 99°C. The resulting optical assembly was removed from the injection molding machine after a total injection molding cycle time of 66 seconds. Visual inspection of the film before and after the thermoforming and molding process showed no noticeable change in reflectance.

[0161] A crosshatch tape pull test was used to test the bond strength of the film to the lens. This was done by scoring the insert molded film on the lens surface with a crosshatch pattern, adhering tape onto the scored crosshatch film surface, and pulling the tape away from the surface. It was found that a portion of the multilayer optical film was removed with the tape, separating the multilayer optical film and leaving another portion on the lens. It was concluded that the PMMA molding material bonded strongly to the outer layer of the APF film, which was a blend of polycarbonate and copolyester (PC:coPET). For comparison, a cyclic olefin resin was injection molded into a thermoformed APF in a similar process and tested for adhesion as described above. It was found that the APF was completely removed with the tape, without leaving any optical film on the lens.

[0162] To determine the retardance of the lenses made by injection molding, lenses were formed as described above without the optical film and the retardance was measured using an Axometrics AxoScan™ Muller matrix polarimeter (available from Axometrics, Inc., Huntsville, AL). The lenses had a fairly constant thickness of about 2 mm, a radius of curvature of 36 mm, and a diameter of 70 mm. The retardance in nm as a function of polar angle and azimuth angle (using the spherical coordinates of the polar angle measured from the apex of the lens) is shown in Table 1. A wavelength of 550 nm was used and the results were averaged over 20 scans. Duplicate points were measured to determine the repeatability of the results (e.g., a polar angle of 48 degrees and an azimuth angle of 0 degrees corresponds to a polar angle of minus 48 degrees and an azimuth angle of 180 degrees). The retardance changed more in the direction from the gate side (at a polar angle of about -48 degrees and an azimuth angle of about 0 degrees) to the opposite side of the lens and changed less in the orthogonal direction. The retardance was higher than 10 nm in a small region near the gate and less than 10 nm over at least 80% of the lens. It is believed that longer annealing times will reduce the retardance near the gate, thereby resulting in a retardance less than 10 nm throughout the lens.

[0163] [Table 1]

[0164] Example 2: Insert molding of lenses onto optical stack of APF and liner The optical stack was thermoformed into an 8-base lens shape as generally described in U.S. Patent No. 9,557,568 (Ouderkirk et al.). The optical stack was a multilayer optical film reflective polarizer (APF) with a protective film liner (OCPET NSA33T, Sun A Kaken Co, Ltd) disposed on each major surface of the APF. The liner was aligned with the APF and did not extend beyond the edges of the APF.

[0165] The optical stack insert molding was performed on a Krauss Maffei 65 ton injection molding machine using an 8 base lens blank injection molding tool. The thermoformed optical stack was trimmed to the correct size to fit the injection molding tool and one of the liners was removed. The thermoformed optical stack was then placed on the convex side of the mold tool with the remaining liner facing away from the mold cavity. The injection molding process was then performed using PMMA molding material (Optimas 7500, Mitsubishi Gas Chemical Company, Inc.) injected at a temperature of 268°C into the mold tool cavity at 82°C. The resulting optical assembly was removed from the injection molding machine after a total injection molding cycle time of 66 seconds.

[0166] The bond strength of the film to the lens was tested as in Example 1. It was found that a portion of the multilayer optical film could be removed with tape, separating the multilayer optical film and leaving another portion on the lens.

[0167] Descriptions of elements in the figures should be understood to apply equally to corresponding elements in other figures unless otherwise indicated. Although specific embodiments have been illustrated and described herein, those skilled in the art will recognize that various alternative and / or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. The present application is intended to cover any adaptations or variations of the specific embodiments described herein. Accordingly, the present disclosure is to be limited only by the claims and their equivalents.

[0168] Any of the above references, patents, or patent applications are incorporated herein by reference in their entirety in a consistent manner. In the event of any inconsistency or contradiction between any of the incorporated references and this application, the information in the above description shall prevail.

Claims

1. 1. An optical assembly comprising: an integrally formed multilayer optical film; a first optical element injection insert molded directly onto the multilayer optical film, the multilayer optical film comprising a plurality of alternating birefringent and isotropic polymer layers that reflect or transmit light by optical interference, each location over at least 80% of a total area of ​​the multilayer optical film having a reflectivity greater than 80% for normally incident light having the same predetermined wavelength and the same first polarization state; the melting temperature of the first optical element is at least 50° C. higher than the glass transition temperature of the optical multilayer film; An optical assembly, wherein the difference between the melting temperature of the first optical element and the melting temperature of the multilayer optical film is less than 10°C.

2. The optical assembly of claim 1 , wherein the melting temperature of the first optical element is at least 80° C. higher than the glass transition temperature of the multilayer optical film.

3. The multilayer optical film is diffusion bonded to the first optical element; the bond of the multilayer optical film to the first optical element is stronger than an interlayer bond between at least one pair of immediately adjacent layers in the multilayer optical film; 10. The optical assembly of claim 1.

4. Each location over at least 90% of the total area of ​​the multilayer optical film has a reflectivity of greater than 90% for normally incident light having the same predetermined wavelength and the same first polarization state; the multilayer optical film is diffusion bonded to the first optical element; 10. The optical assembly of claim 1.

5. The first optical element is a lens, the lens has an optical retardance that varies more along its largest lateral dimension in a first direction and less along its largest lateral dimension in an orthogonal second direction, the optical retardance at each location on the lens being about 10 nm or less.

10. The optical assembly of claim 1.

6. The first optical element is a lens, the multilayer optical film has opposing first and second major surfaces, the first major surface disposed on a first portion of a first side of the lens; The optical assembly of claim 1 , wherein a second portion of the first side of the lens is coplanar with the second major surface of the multilayer optical film.

7. The first optical element is a lens, the lens at least partially wraps around an edge of the multilayer optical film; 10. The optical assembly of claim 1.

8. The first optical element is a lens having a first major surface defining a curved recess therein; the multilayer optical film is adhesively conforming to the curved recess; 10. The optical assembly of claim 1.

9. A lens, wherein a lens thickness at a first lens position is at least 20% greater than a lens thickness at a second lens position; 6. The optical assembly of claim 5.

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