Optical lens comprising an optical film bonded to a lens substrate

Abstract

An optical lens comprising a lens substrate comprising a cyclic olefin copolymer; an optical film comprising a plurality of alternating first and second polymer layers; and a bonding film disposed on a major surface of the lens substrate and bonding the optical film to the major surface of the lens substrate. The bonding film has an average peel force to separate the optical film from the lens substrate of greater than about 100 g / in while at least one outermost major surface of the optical film maintains an average displacement surface roughness Sa of less than about 10 nm and a tilt magnitude error of less than about 100 μrad, and / or a lower spatial frequency tilt magnitude error and a higher spatial frequency tilt magnitude error each of less than about 100 μrad.

Description

Background Technology

[0001] Optical lenses can be used in a variety of applications. For some applications, it is desirable to place optical films, such as reflective polarizing films, on the main surface of the lens substrate. Summary of the Invention

[0002] This invention relates generally to an optical lens comprising an optical film bonded to a lens substrate by an adhesive film. The optical film may be a multilayer optical film comprising a plurality of alternating polymer layers, and the lens substrate may be a cyclic olefin copolymer lens substrate. The adhesive film is adapted to bond the optical film to the lens substrate with a desired adhesive strength while maintaining a desired low surface texture or substantially no surface texture in the optical film.

[0003] In some aspects of this specification, an optical lens is provided. The optical lens includes a lens substrate having opposite first and second primary surfaces, wherein at least one of the first and second primary surfaces is curved. The lens substrate comprises a cyclic olefin copolymer. The optical lens includes an optical film comprising a plurality of alternating first and second polymer layers, totaling at least 10. Each of the first and second polymer layers has an average thickness of less than about 500 nm. The optical lens includes an adhesive film comprising an adhesive layer having a composition different from both the cyclic olefin polymer and the cyclic olefin copolymer, and having a refractive index in the range of 1.45 to 1.6.

[0004] In some embodiments, an adhesive film is disposed on the first main surface and the optical film is bonded to the first main surface, such that the average peel force separating the optical film from the lens substrate is greater than about 100 g / in, while at least one outermost main surface of the optical film maintains an average displacement surface roughness Sa of less than about 10 nm and a tilt value error of less than about 100 μrad.

[0005] In some embodiments, the adhesive film is disposed on the first major surface and bonds the optical film to the first major surface, and the average peel force for separating the optical film from the lens substrate is greater than about 100 g / in while the at least one outermost major surface of the optical film maintains both a lower spatial frequency tilt magnitude error and a higher spatial frequency tilt magnitude error less than about 100 μrad. The lower spatial frequency tilt magnitude error and the higher spatial frequency tilt magnitude error are determined from surface profiles filtered with respective lower spatial frequency bandpass Fourier filters and higher spatial frequency bandpass Fourier filters. The higher spatial frequency bandpass Fourier filter has band edge wavelengths of W1 and W2, and the lower spatial frequency bandpass Fourier filter has band edge wavelengths of W3 and W4, where 0.1 mm ≤ W1 < W2 ≤ W3 < W4 ≤ 10 mm, W2 ≥ 2W1, and W4 ≥ 2W3.

[0006] These and other aspects will become apparent from the following detailed description. However, in no event should the foregoing summary be construed as limiting the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figures 1 to 2 is a schematic cross-sectional view of an optical lens according to some embodiments.

[0008] Figure 3 [[ID=十三]]

[0009] Figure 4 Schematically shows the determination of various surface characterizations from a surface profile.

[0010] Figure 5 Schematically shows surface roughness and tilt error.

[0011] Figures 6A to 6C is a schematic diagram of a bandpass Fourier filter according to some embodiments. DETAILED DESCRIPTION

[0012] In the following description, reference is made to the accompanying drawings, which form a part of the present invention and in which various embodiments are shown by way of illustration. The drawings are not necessarily to scale. It should be understood that other embodiments may be envisioned and effected without departing from the scope or spirit of the present specification. Accordingly, the following detailed description should not be taken in a limiting sense.

[0013] ​Optical lenses with optical films bonded to a lens substrate can be used in a wide range of applications. For example, reflective polarizing films bonded to a lens substrate can be used in optical systems utilizing folded optics designs, such as those broadly described in U.S. Patent 10,678,052 (Ouderkirk et al.). In some cases, it is desirable to use lens substrates formed of cyclic olefin copolymers (COCs) due to desired optical properties of such materials, such as low birefringence and / or low dispersion (refractive index as a function of wavelength) and / or low haze. For example, COC lens substrates can be formed by inserting COC resin into an optical film via injection molding, or the optical film can be bonded to a previously formed lens substrate via an optically transparent adhesive. However, for multilayer optical films comprising multiple alternating polymer layers, it has been found difficult to achieve adequate bonding between the optical film and the lens substrate without undesirably increasing the surface texture (e.g., roughness or waviness) of one or both outermost principal surfaces of the optical film at the same time. For example, a wide range of adhesives may be used between the optical film and the lens substrate, but many of these adhesives result in poor adhesion and / or undesirable surface textures in the optical film.

[0014] According to some embodiments of the invention, an adhesive film can be disposed between an optical film and a lens substrate to provide desired high peel strength (e.g., greater than about 100 g / in), desired low surface texture (e.g., average displacement surface roughness Sa less than about 10 nm and / or tilt magnitude error less than about 100 μrad), and desired optical properties (e.g., the adhesive film may include an adhesive layer adjacent to the optical film, the refractive index of which is within about 0.1 of the refractive index of the lens substrate). Suitable materials for the adhesive layer have been found to include copolymers containing ethylene and vinyl acetate groups, copolymers containing styrene and butadiene groups, and optically transparent adhesives containing (meth)acrylate groups having a straight-chain alkyl chain with at least four carbons and having a glass transition temperature not exceeding 25°C. The term "(meth)acrylate" is used to refer to both acrylate and methacrylate compounds. For example, solvent-deposited polymer layers have been found to result in low surface texture. Adhesive layers having low glass transition temperatures (e.g., not exceeding 25°C or not exceeding 0°C) have been found to provide high adhesion to the optical film. In some embodiments, the adhesive layer is or includes (e.g., solvent-deposited) ethylene vinyl acetate, (e.g., solvent-deposited) styrene-butadiene rubber, or (meth)acrylate (containing acrylate groups having a straight-chain alkyl chain containing at least 4 carbons), wherein the adhesive layer has a glass transition temperature not exceeding 25°C.

[0015] Figure 1 and Figure 2These are schematic cross-sectional views of optical lenses 100 and 100' according to some embodiments. Optical lens 100 (and correspondingly 100') includes a lens substrate 110 (and correspondingly 110') having opposing first and second main surfaces 111 and 112 (and correspondingly 111' and 112'), an optical film 120, and an adhesive film 130 disposed on the first main surface 111 (and correspondingly 111') and bonding the optical film 120 to the first main surface 111 (and correspondingly 111'). The adhesive film includes an adhesive layer. Figure 1 In the illustrated embodiment, the adhesive film 130 is an adhesive layer. Figure 2 In the illustrated embodiments, in addition to the adhesive layer 132, the adhesive film 130' also includes a carrier layer or substrate 131. In other embodiments, the adhesive film includes an adhesive layer on the opposite side of the carrier or substrate layer. The lens substrate 110 (correspondingly 110') is typically formed of a cyclic olefin copolymer (COC). In some embodiments, the carrier layer or substrate 131 is an olefin substrate adapted to be bonded to the lens substrate when the lens is injection molded onto the adhesive film. In some such embodiments, the adhesive layer is selected to bond to both the olefin substrate and the outermost layer of the optical film. The adhesive film typically contacts the main surfaces of both the COC lens substrate and the optical film directly.

[0016] Lens substrates 110 and 110' can have any suitable geometry. For example, the lens substrate can be a biconvex lens, plano-convex lens, positive meniscus lens, negative meniscus lens, plano-concave lens, or biconcave lens substrate. The lens substrate can be integral or a single piece. In the case of compound lenses, the lens substrate can refer to the lens element facing the optical film, such that the adhesive film directly bonds the optical film to the lens element, which can be integral or a single piece.

[0017] In some embodiments, the adhesive film 103' includes an olefin substrate 131, wherein an adhesive layer 132 is disposed on and substantially co-elongated with the olefin substrate 131, and wherein the adhesive layer 132 faces the optical film 120. The substrate 131 may be, for example, a cyclic olefin polymer (COP) substrate. Layers may be described as substantially co-elongated with each other if at least about 60% of each layer is co-elongated with at least about 60% of each other layer. In some embodiments, for layers described as substantially co-elongated, at least about 70%, or at least about 80%, or at least about 90% of each layer is co-elongated with at least about 70%, or at least about 80%, or at least about 90% of each other layer. The adhesive film may be a single adhesive layer or may include an adhesive layer and at least one other layer. The adhesive film may be a self-supporting film (e.g., including a carrier and an adhesive layer disposed on the carrier) or may be a non-self-supporting film (e.g., an adhesive layer formed as a coating on an optical film, which may be a non-self-supporting film).

[0018] In some embodiments, the adhesive layer has a composition different from both cyclic olefin polymers and cyclic olefin copolymers. In other words, in some embodiments, the adhesive layer is neither a cyclic olefin polymer nor a cyclic olefin copolymer. In some embodiments, the adhesive layer has a refractive index close to that of the lens substrate. For example, the lens substrate may have a refractive index of about 1.53, while the adhesive layer may have a refractive index in the range of, for example, 1.45 to 1.6. The refractive index can be measured at a wavelength of about 589 nm (sodium D-line) and can be determined according to, for example, ASTM D542-14 test standards.

[0019] Suitable adhesive layers have been found to include copolymers containing ethylene and vinyl acetate groups, copolymers containing styrene and butadiene groups, or certain optically transparent adhesives, such as those comprising or based on (meth)acrylates, such as polymers containing (meth)acrylate groups having a straight-chain alkyl chain having at least 4, 6, or 8 carbons, and preferably having a glass transition temperature not exceeding 25°C. In some embodiments, each (meth)acrylate group comprises at least 20% or at least 50% of a straight-chain alkyl chain having at least 4, 6, or 8 carbons, based on the number of (meth)acrylate groups in the polymer. Suitable (meth)acrylates include poly(n-butyl methacrylate) polymers such as ELVACITE 2044 or 4325 (available from Lucite International, Cordova, TN) or acrylate adhesives available as CEF19 Contrast Enhancement Film from 3M Company, St. Paul, MN, USA. In some embodiments, the adhesive layer is or comprises an optically clear adhesive containing long-chain (meth)acrylates. As used herein, long-chain (meth)acrylates are polymers comprising (meth)acrylate groups having a straight-chain alkyl chain containing at least 8 carbons. In some embodiments, each (meth)acrylate group comprises at least 20% or at least 50% of the number of (meth)acrylate groups in the polymer, containing a straight-chain alkyl chain containing at least 8 carbons, or at least 10 carbons, or at least 12 carbons, or at least 14 carbons. Long-chain (meth)acrylates are described in, for example, U.S. Patent Application Publication 2018 / 0094173 (Everaerts). Suitable copolymers comprising ethylene and vinyl acetate groups include, for example, ethylene vinyl acetate (EVA or VAE) ELVAX 40W (available from Dow Chemical Company, Midland, MI), ATEVA 3325 and 4030 (available from Celanese, Irving, TX), DUR-O-SET E352 (available from Celanese, Irving, TX), and FLEXBOND 150 (available from Celanese, Irving, TX). For example, the vinyl acetate content in ethylene vinyl acetate can range from 10 to 80, or 20 to 50, or 30 to 45 mol%.Suitable copolymers containing styrene and butadiene groups include, for example, styrene-butadiene rubber BUTOFAN NS 222 (purchased from BASF, Ludwigshafen, Germany).

[0020] In some embodiments, the adhesive layer is or includes a solvent-deposited polymer. Solvent-deposited polymers have been found to provide thin layers with low surface roughness and low tilt size error. The solvent-deposited layer is formed by coating a mixture of polymer and solvent (e.g., a solution or emulsion) and then removing the solvent. The solvent can be a solvent used for the polymer, or the polymer can be insoluble in the solvent (e.g., an aqueous emulsion of the polymer can be used). Suitable solvents include water, toluene, methyl ethyl ketone (MEK), alcohols and glycol ethers (e.g., DOWANOLPM available from Dow Chemical Company) or combinations thereof.

[0021] In some embodiments, the adhesive layer comprises a substantially nonpolar polymer. In some embodiments, the adhesive layer comprises a polymer having a substantially aliphatic backbone (e.g., aliphatic or containing no more than about 10 mol% aromatic groups). In some embodiments, the substantially aliphatic backbone contains less than about 10 mol%, or less than about 5 mol%, or less than about 1 mol% aromatic groups.

[0022] In some embodiments, the adhesive layer has an average thickness t1 of less than about 30 micrometers, or less than about 25 micrometers, or less than about 20 micrometers, or less than about 15 micrometers, or less than about 10 micrometers. In some such embodiments, or in others, the adhesive layer has an average thickness of at least about 2 micrometers, or at least about 3 micrometers, or at least about 5 micrometers. For example, in some embodiments, the average thickness t1 is in the range of about 2 micrometers to about 25 micrometers, or about 3 micrometers to about 20 micrometers. Typically, if the thickness of the adhesive layer is too large, the surface texture of the optical film becomes too large when it is bonded to the lens substrate, while if the thickness of the adhesive layer is too small, the adhesion is too weak. In some cases, the preferred thickness range may depend on the material of the adhesive layer.

[0023] In some embodiments, the adhesive layer has a glass transition temperature (Tg) of less than or greater than 25°C, or not greater than 10°C, or not greater than 0°C, or not greater than -10°C, or not greater than -15°C, or not greater than -20°C. In some such embodiments or in others, the glass transition temperature is at least -60°C, at least -50°C, or at least -45°C. For example, in some embodiments, the glass transition temperature is in the range of -60°C to 25°C or to 0°C, or in the range of -45°C to 0°C. The glass transition temperature can be determined by differential scanning calorimetry (DSC) as known in the art. For example, the glass transition temperature can be determined as an onset temperature according to the ASTM E1356-08 (2014) test standard. It has been found that lower (e.g., not greater than 25°C or not greater than 0°C) glass transition temperatures can result in improved adhesion and lower surface texture.

[0024] In some implementations, the average peeling force F that separates the optical film from the lens substrate (see, for example) Figure 2 The force is greater than about 100 g / in, or greater than about 300 g / in, or greater than about 500 g / in, or greater than about 700 g / in, or greater than about 900 g / in, or greater than about 1000 g / in. In some embodiments, the optical film comprises a plurality of alternating first polymer layers and second polymer layers, and the average peel force F separating the optical film from the lens substrate is greater than the average interlayer delamination force Fd of the plurality of alternating first polymer layers and second polymer layers (see, for example...). Figure 3 The average peel force F (force per unit width) can be determined using a 90-degree peel test, averaging over 5 seconds at a peel speed of 6 inches per minute. The lens substrate can be held stationary, and the optical film is peeled along a fixed Cartesian direction that defines a 90-degree peel angle at the center or apex of the lens's main surface. The average interlaminar delamination force Fd of the optical film can be determined using the same peel test as the average peel force F, except that the optical film is scratched at an angle with a razor blade before the peel test to test the delamination. Suitable delamination testing methods are described, for example, in U.S. Patent 10,288,789 (Johnson et al.).

[0025] Figure 3 This is a schematic cross-sectional view of an optical film 120 according to some embodiments. The optical film 120 includes a plurality of alternating first polymer layers 121 and second polymer layers 122, totaling at least 10. The number of alternating first polymer layers 121 and second polymer layers 122 may be substantially greater than [amount missing]. Figure 3The quantities are schematically shown. For example, the total number of the plurality of alternating first polymer layers 121 and second polymer layers 122 may be at least 50, at least 100, or at least 150. In some embodiments, the total number of the plurality of alternating first polymer layers 121 and second polymer layers 122 may not exceed 1000 or 800. Each of the first polymer layers 121 and second polymer layers 122 has an average thickness (e.g., average thickness t0) of less than about 500 nm, less than about 400 nm, or less than about 300 nm. The optical film 120 includes a first outermost layer 124 and a second outermost layer 126, each of which may have an average thickness greater than about 500 nm, greater than about 1 micrometer, or greater than about 2 micrometers.

[0026] Alternating first polymer layers 121 and second polymer layers 122 can be selected to provide desired reflection and transmission spectra. As is known in the art, optical films comprising alternating polymer layers can be used to provide desired reflection and transmission in desired wavelength ranges by appropriately selecting layer thicknesses and refractive index differences. Multilayer optical films and methods of manufacturing multilayer optical films are described, for example, in U.S. Patent Nos. 5,882,774 (Jonza et al.); 6,179,948 (Merrill et al.); 6,783,349 (Neavin et al.); 6,967,778 (Wheatley et al.); and 9,162,406 (Neavin et al.).

[0027] In some embodiments, the optical film 120 is a reflective polarizer that substantially transmits (e.g., at least about 60%, or at least about 70%, or at least about 80% of the average transmittance in the wavelength range of 450 nm to 650 nm) substantially perpendicularly incident (e.g., within 20 degrees, or 10 degrees, or 5 degrees of the normal) light 301 having a first polarization state 302, and substantially reflects (e.g., at least about 60%, or at least about 70%, or at least about 80% of the average reflectance in the wavelength range of 450 nm to 650 nm) substantially perpendicularly incident light 301 having a second polarization state 303 orthogonal to the first polarization state 302. Figure 3 Transmitted light 304 and reflected light 305 are schematically shown. Suitable reflective polarizers include, for example, 3M Advanced Polarizing Film (APF), available from 3M Company, St. Paul, MN, USA. Other suitable optical films include those described below: for example, International Patent Application WO 2020 / 012416 (Le et al.) and U.S. Patent Application Publication WO 2020 / 0183065 (Haag et al.).

[0028] In some embodiments, the optical film has a first outermost major surface 127 facing the lens substrates 110, 110' and an opposite second outermost major surface 129 facing away from the lens substrates 110, 110'. In some embodiments, the first outermost major surface 127 has a lower average displacement surface roughness than the second outermost major surface 129. For example, according to some embodiments, Figure 3 the average displacement surface roughnesses Sa1 and Sa2 of the first outermost major surface 127 and the second outermost major surface 129 are schematically shown. For example, in some embodiments, Sa1 < Sa2, or Sa1 < 0.9Sa2, or Sa1 < 0.8Sa2. In other embodiments, the first outermost major surface 127 has a higher average displacement surface roughness than the second outermost major surface 129. The optical film 120 can be formed by co-extruding alternating polymer layers with an outermost protective boundary layer and / or skin layer, casting the co-extruded layers onto a casting wheel, and then stretching the cast sheet. The outermost major surface of the optical film facing the casting wheel can have a higher surface roughness than the opposite outermost major surface. The optical film 120 can be oriented such that the rougher outermost major surface faces away from the lens substrate. In other embodiments, the first outermost major surface 127 has a higher average displacement surface roughness than the second outermost major surface 129.

[0029] In some embodiments, the optical film 120 includes a first outermost layer 124 facing the adhesive layers 130, 132. The optical film 120 can also include a second outermost layer 126 opposite the first outermost layer 124. In some embodiments, the first outermost layer 124 and in some cases the second outermost layer 126 comprise polycarbonate. In some embodiments, the first outermost layer 124 and in some cases the second outermost layer 126 comprise a blend of polycarbonate and copolyester.

[0030] In some embodiments, the adhesive films 130, 130' have an average peel force F for separating the optical film 120 from the lens substrates 110, 110' that is greater than about 100 g / in, while at least one outermost major surface of the optical film 120 (e.g., outermost major surface 127 or 129) maintains at least two surface characterizations within a desired corresponding range. The at least two surface features can include an average displacement surface roughness Sa, which can be, for example, less than about 10 nm. The at least two surface characterizations can include at least one tilt magnitude error, which can be less than, for example, about 100 μrad. The tilt magnitude error can be represented as <|θ|> to represent the average value of the absolute value of the tilt error. The at least two surface characterizations can include a lower spatial frequency tilt magnitude error and a higher spatial frequency tilt magnitude error <|θ|> H and <|θ|> HBoth can be less than, for example, about 100 μrad. At least two surface characterizations can be determined on at least two different length scales. Figure 4 The diagram schematically illustrates starting from a surface profile (e.g., the surface displacement profile of the outermost principal surfaces 127 or 129) and applying different Fourier filters (Fourier filters 1, 2, etc.) to achieve different surface representations (surface representations 1, 2, etc.). For example, surface representations 1 and 2 could be Sa and <|θ|> or <|θ|>. L and <|θ|> H For example, in some embodiments, surface characterization 1 to 3 is measured, which can be Sa, <|θ|> L and <|θ|> H . Figure 5 A filtered surface profile 328 with an average displacement surface roughness Sa and a tilt error θ is schematically shown, which can be described as the local tilt of the surface relative to the desired surface. The average (unweighted average) magnitude of θ is the tilt magnitude error.

[0031] The tilt magnitude error is determined based on a surface profile filtered to remove horizontal, spherical, and cylindrical terms. As used herein, the tilt magnitude error is determined based on a surface profile further filtered to remove surface roughness length scale errors (e.g., less than about 0.3 mm, or less than about 0.1 mm) and long length scale errors (e.g., shape errors on the length scale greater than about 10 mm, or greater than about 5 mm, or greater than about 2 mm, or greater than about 1 mm). The tilt magnitude error may also be referred to as mid-spatial frequency tilt error, mid-wavelength tilt error, or waviness. For example, the tilt magnitude error can be determined based on a surface profile filtered with a passband Fourier filter having band-edge wavelengths W1 and W2 (where 0.1 mm ≤ W1 ≤ 0.3 mm and W1 ≤ W2 ≤ 10 mm). In some embodiments, 2W1 ≤ W2 or 3W1 ≤ W2. In some embodiments, W2 ≤ 5 mm, or W2 ≤ 2 mm, or W2 ≤ 1 mm. For example, in some embodiments, 3W1 ≤ W2 ≤ 1 mm. In some embodiments, W1 is about 0.1 mm and W2 is about 0.3 mm, or W1 is about 0.3 mm and W2 is about 1 mm, or W1 is about 0.1 mm and W2 is about 1 mm. In some embodiments, the tilt magnitude error is determined based on the surface profile filtered by a passband Fourier filter having band-side wavelengths of, for example, about 0.1 mm and about 0.3 mm, or about 0.3 mm and about 1 mm, or about 0.1 mm and about 1 mm. For example, the tilt magnitude error determined for any one or more of these frequency ranges may be less than 100 μrad, or less than about 80 μrad, or less than about 60 μrad, or less than about 55 μrad, or less than about 50 μrad. For example, the tilt magnitude error may be in the range of 5 μrad to 100 μrad or 10 μrad to 60 μrad.

[0032] In some embodiments, the tilt magnitude error is defined for at least two different spatial frequency ranges. For example, a lower spatial frequency tilt magnitude error and a higher spatial frequency tilt magnitude error can be determined based on surface profiles filtered with a corresponding lower spatial frequency bandpass Fourier filter and a higher spatial frequency bandpass Fourier filter, where the higher spatial frequency bandpass Fourier filter has band edge wavelengths of W1 and W2, and the lower spatial frequency bandpass Fourier filter has band edge wavelengths of W3 and W4, and where 0.1 mm ≤ W1 < W2 ≤ W3 < W4 ≤ 10 mm, W2 ≥ 2W1, and W4 ≥ 2W3. For example, in some embodiments, W1 is about 0.1 mm, W2 and W3 are each about 0.3 mm, and W4 is about 1 mm. For example, the lower spatial frequency tilt magnitude error and the higher spatial frequency tilt magnitude error can each be less than about 100 μrad, or can be within any of the ranges of tilt magnitude error described elsewhere herein. In some embodiments, the lower spatial frequency tilt magnitude error is less than the higher spatial frequency tilt magnitude error. In some embodiments, the higher spatial frequency tilt magnitude error is less than the lower spatial frequency tilt magnitude error. For example, in some embodiments, at least one of the higher and lower spatial frequency tilt magnitude errors is less than about 60 μrad, or less than about 55 μrad, or less than about 50 μrad, or less than about 45 μrad.

[0033] The average displacement surface roughness Sa is determined from a surface profile filtered to remove the horizontal, spherical, and cylindrical terms. As used herein, the average displacement surface roughness Sa is determined from a surface profile further filtered to remove the medium spatial frequency slope error length scale and the longer length scale. For example, the slope magnitude error can be determined from a surface profile filtered with a band-pass Fourier filter having band-edge wavelengths W1 and W2, where 0.1 mm ≤ W1 ≤ 0.3 mm and W1 ≤ W2 ≤ 10 mm, and the surface roughness can be determined from a surface profile filtered with a band-pass Fourier filter having band-edge wavelengths Wa and Wb, where Wa < Wb ≤ W1, or 1.5Wa < Wb ≤ W1, or 2Wa < Wb ≤ W1. In some embodiments, Wb is about 0.1 mm, or about 0.2 mm, or about 0.3 mm. In some such embodiments, or in other embodiments, Wa is about 0.06 mm, or about 0.05 mm, or about 0.04 mm. For example, in some embodiments, the average displacement surface roughness Sa is determined from a surface profile filtered with a band-pass Fourier filter having band-edge wavelengths of about 0.06 mm and about 0.1 mm. When determining the lower spatial frequency slope magnitude error and the higher spatial frequency slope magnitude error, the average displacement surface roughness Sa can be determined from a surface profile filtered to remove both the lower spatial frequency slope magnitude error and the higher spatial frequency slope magnitude error length scales. In some embodiments, the average displacement surface roughness Sa is less than about 10 nm, or less than about 8 nm, or less than about 6 nm, or less than about 5 nm. The average displacement surface roughness Sa can be in the range of, for example, about 1 nm to about 10 nm or to about 8 nm.

[0034] For example, the average displacement surface roughness Sa and the slope magnitude error can be determined as an average over an area in the clear aperture of the lens and / or near the center of the film. The area can be an approximately elliptical or circular or rectangular or square area, the dimensions of which (e.g., major diameter and minor diameter or width and length) are at least the reciprocal of the minimum frequency of the Fourier filter. In some embodiments, an approximately square area having a width of about 4 mm is used.

[0035] Figure 6A is a schematic diagram of a band-pass Fourier filter 250 showing the size of the filter versus spatial frequency according to some embodiments. The band-pass Fourier filter 250 has band-edge frequencies F1 and F2 and corresponding band-edge wavelengths W1' (associated with the corresponding band-edge frequency of 1 / F1) and W2' (associated with the corresponding band-edge frequency of 1 / F2), which can correspond to wavelengths W1 and W2, or W3 and W4, or Wa and Wb as described elsewhere herein. Alternatively, the Fourier filter can be plotted as a function of wavelength (the reciprocal of spatial frequency). Figure 6BThese are schematic diagrams of bandpass Fourier filters 251 and 252 according to some embodiments, illustrating the filter size relative to wavelength. For example, bandpass Fourier filter 251 has band-side wavelengths Wa and Wb and can be used to define a surface roughness Sa. For example, bandpass Fourier filter 252 has band-side wavelengths Wc and Wd (which may alternatively be represented as W1 and W2) and can be used to define a tilt magnitude error. In the illustrated embodiment, Wc = Wb. In other embodiments, Wc > Wb. Figure 6C These are schematic diagrams of bandpass Fourier filters 251, 253, and 254 according to some embodiments, illustrating the filter size relative to wavelength. For example, bandpass Fourier filter 253 has band-side wavelengths W1 and W2 and can be used to limit the tilt magnitude error at higher spatial frequencies (lower wavelengths). In the illustrated embodiment, W1 = Wb. In other embodiments, W1 > Wb. For example, bandpass Fourier filter 254 has band-side wavelengths W3 and W4 and can be used to limit the tilt magnitude error at lower spatial frequencies (higher wavelengths). In the illustrated embodiment, W3 = W2. In other embodiments, W3 > W2.

[0036] In some embodiments, the optical lens 100 (correspondingly 100') includes a lens substrate 110 (correspondingly 110') having a first primary surface 111 and opposite second primary surfaces 112 (correspondingly 111' and 112'), wherein at least one of the first primary surface and the second primary surface is curved, and wherein the lens substrate 110 (correspondingly 110') is or includes a cyclic olefin copolymer; an optical film 120 comprising a plurality of alternating first polymer layers 121 and second polymer layers 122 totaling at least 10, wherein each of the first polymer layers 121 and the second polymer layers 122 has an average thickness (e.g., average thickness t0) of less than about 500 nm; and an adhesive film 130 (correspondingly 130') comprising an adhesive layer 130 (correspondingly 132) having a composition different from that of the cyclic olefin polymer and the cyclic olefin copolymer and having a refractive index in the range of 1.45 to 1.6.

[0037] In some embodiments, an adhesive film 130 (correspondingly 130') is disposed on a first main surface 111 (correspondingly 111') and the optical film is bonded to the first main surface 111 (correspondingly 111'), such that the average peel force F separating the optical film 120 from the lens substrate 110 (correspondingly 110') is greater than about 100 g / in, while at least one outermost main surface of the optical film 120 (e.g., outermost main surface 127 or outermost main surface 129, or both outermost main surfaces 127 and 129) maintains an average displacement surface roughness Sa of less than about 10 nm (e.g., corresponding to...). Figure 5 The Sa shown Figure 4 the surface characterization 1) shown in Figure 5 and an inclination magnitude error less than about 100 μrad (e.g., corresponding to the average value of the magnitude of the angle θ shown in Figure 4 the surface characterization 2) shown in Figure 6B In some embodiments, the inclination magnitude error is determined based on the surface profile filtered by a band - pass Fourier filter having edge wavelengths W1 and W2 (e.g., corresponding to the wavelengths Wc and Wd depicted in Figure 6C the wavelengths W1 and W2 depicted in Figure 6C the wavelengths W3 and W4 depicted in ), where 0.1 mm ≤ W1 ≤ 0.3 mm, and 2W1 ≤ W2 ≤ 10 mm, or where W1 and W2 are within any range described elsewhere herein.

[0038] In some embodiments, an adhesive film 130 (correspondingly 130') is disposed on the first major surface 111 (correspondingly 111') and bonds the optical film to the first major surface 111 (correspondingly 111'), and the average peel force F for separating the optical film 120 from the lens substrate 110 (correspondingly, 110') is greater than about 100 g / in, while at least one outermost major surface of the optical film 120 (e.g., the outermost major surface 127 or 129) maintains a lower spatial - frequency inclination magnitude error and a higher spatial - frequency inclination magnitude error both less than about 100 μrad (e.g., corresponding to Figure 4 the surface characterizations 1 and 2 shown in Figure 4 the Fourier filters 1 and 2 depicted in Figure 6C the Fourier filters 254 and 253 depicted in ). The lower - spatial - frequency inclination magnitude error and the higher - spatial - frequency inclination magnitude error are determined based on the surface profile filtered by the corresponding lower - spatial - frequency band - pass Fourier filter and higher - spatial - frequency band - pass Fourier filter (e.g., corresponding to Figure 6C ). In some embodiments, 0.1 mm ≤ W1 < W2 ≤ W3 < W4 ≤ 10 mm, W2 ≥ 2W1, and W4 ≥ 2W3; or W1, W2, W3, and W4 can be within any range described elsewhere herein.

[0039] Example

[0040] Unless otherwise indicated, all parts, percentages, and ratios reported in the following examples are based on weight.

[0041] Material

[0042]

[0043]

[0044]

[0045] Lens substrates are formed on an optical film by insert injection molding. Prior to injection molding, an adhesive layer is applied to the optical film, which is then placed into a mold. The optical film is a polymer multilayer optical film reflective polarizer, as described in Example 1 of International Patent Application WO2020 / 012416 (Le et al.). The adhesive layer is either applied directly to the optical film or first applied to a release liner and then transferred to the optical film. In these specific samples, the lens substrates formed by injection molding have a flat main surface facing the optical film and a curved main surface opposite it. The following molding conditions are used:

[0046]

[0047]

[0048] The adhesion of the packaging tape was used to test the samples to determine whether they were "pass" or "fail". The average peel strength of various pass samples was tested. A 90-degree peel test was performed at a rate of 6 inches / minute, and the peel force was averaged over 5 seconds. The surface profile of samples that appeared to have low surface texture was determined and characterized as described below.

[0049]

[0050]

[0051] Optical lenses comprising optical films were prepared by insert molding using adhesive layers deposited with various solvents, as described above. For the ELVACITE sample, the solvent was isopropanol (IPA). For the EVA sample, the solvent was toluene or a blend of toluene and methyl ethyl ketone (MEK), ranging from 100% toluene to a 50 / 50 mixture of toluene and MEK. For the emulsion, the solvent was water. The average peel force was measured as described above. The surface texture of the outermost master surface of the bonded optical film was examined. If significant surface texture was observed, the surface texture was characterized as “poor”; otherwise, the surface texture was characterized as “acceptable”. The results are reported in the table below: As shown in the table below, some adhesive layers were irradiated with a radiation dose (in Mrad) before the lens substrate was injection molded onto the optical film.

[0052]

[0053]

[0054] An optical lens comprising an optical film bonded to a lens substrate via an adhesive film was prepared as described above. The adhesive film was prepared by coating an adhesive layer, as shown in the table below, onto a cyclic olefin polymer (COP) substrate. The adhesive film was then laminated to the optical film sample, with the adhesive layer facing the optical film. Lamination was performed at room temperature (RT) or 150°F. Insertion molding was performed with the lens substrate formed on the olefin substrate opposite the optical film. The average peel force was measured as described above. The results are reported in the table below:

[0055]

[0056]

[0057] An optical lens was fabricated as described above using adhesive layers deposited with various solvents shown in the table below. The optical lens comprised an optical film bonded to a lens substrate using an adhesive film comprising an adhesive layer and an olefin substrate. The adhesive film was laminated to the optical film at room temperature. A surface profile away from the outermost surface of the lens substrate was measured over a roughly square area of ​​approximately 4 mm width using a white light interferometer (purchased from Bruker Corporation, Billerica, MA). The mean displacement surface roughness Sa and the tilt magnitude error were determined based on the surface profile. The surface profile was filtered using Fourier filters with passband edge wavelengths of 0.06 mm and 1 mm when determining the mean displacement surface roughness Sa. The surface profile was filtered using various Fourier filters with passband edge wavelengths shown in the table below when determining the tilt magnitude error.

[0058]

[0059]

[0060] Other samples prepared with BUTOFAN NS 222 and with a thickness of 16 micrometers or less resulted in poor adhesion.

[0061] Optical lenses were fabricated as described above using adhesive layers deposited with various solvents shown in the table below. The optical lenses comprise an optical film bonded to a lens substrate using an adhesive film comprising the adhesive layer and a COP substrate. The adhesive film was laminated to the optical film at 150℉. The average displacement surface roughness Sa and tilt magnitude error were measured as described above. The results are reported in the table below:

[0062]

[0063] Terms such as “about” will be understood in the context in which they are used and described by those skilled in the art. If it is unclear to those skilled in the art in the context of their use and description of “about” to express quantities of characteristic size, quantity, and physical properties, then “about” will be understood to mean within 10% of a specified value. A quantity given a specified value as “about” can be precisely the specified value. For example, if it is unclear to those skilled in the art in the context of their use and description of this specification, a quantity having a value of about 1 means that the quantity has a value between 0.9 and 1.1, and that the value can be 1.

[0064] All cited references, patents, and patent applications are incorporated herein by reference in their entirety in a consistent manner. In the event of any inconsistency or contradiction between the incorporated references and this application, the information in the foregoing description shall prevail.

[0065] Unless otherwise stated, the description of elements in the accompanying drawings should be understood to apply equally to corresponding elements in the other drawings. While specific embodiments have been illustrated and described herein, those skilled in the art will recognize that various alternative and / or equivalent embodiments may be used instead of the illustrated and described embodiments without departing from the scope of this disclosure. This application is intended to cover any modifications, variations, or combinations of the specific embodiments discussed herein. Therefore, this disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. An optical lens, the optical lens comprising: A lens substrate having opposite first and second main surfaces, at least one of the first and second main surfaces being curved, the lens substrate comprising a cyclic olefin copolymer; An optical film comprising at least 10 alternating first polymer layers and second polymer layers, each of the first polymer layer and the second polymer layer having an average thickness of less than about 500 nm. and An adhesive film comprising an adhesive layer having a composition different from that of a cyclic olefin polymer and a cyclic olefin copolymer and having a refractive index in the range of 1.45 to 1.6, the adhesive film being disposed on a first main surface and bonding an optical film to the first main surface, such that the average peel force separating the optical film from the lens substrate is greater than about 100 g / in, while at least one outermost main surface of the optical film maintains an average displacement surface roughness Sa of less than about 10 nm and a tilt magnitude error of less than about 100 μrad, wherein the adhesive layer has a glass transition temperature of not more than 25 °C, wherein the adhesive layer comprises ethylene vinyl acetate, styrene-butadiene rubber, or (meth)acrylate comprising an acrylate group having a straight-chain alkyl chain containing at least 4 carbons.

2. The optical lens according to claim 1, wherein, The tilt magnitude error is determined based on the surface profile filtered by a bandpass Fourier filter with band-side wavelengths W1 and W2, where 0.1mm ≤ W1 ≤ 0.3mm and 2W1 ≤ W2 ≤ 10mm.

3. The optical lens according to claim 1, wherein, The tilt magnitude error is determined based on the surface profile filtered by a bandpass Fourier filter with band-side wavelengths of approximately 0.1 mm and approximately 0.3 mm.

4. The optical lens according to claim 1, wherein, The tilt magnitude error is determined based on the surface profile filtered by a bandpass Fourier filter with band-side wavelengths of approximately 0.3 mm and approximately 1 mm.

5. The optical lens according to claim 1, wherein, The tilt magnitude error is determined based on the surface profile filtered by a bandpass Fourier filter with band-side wavelengths of approximately 0.1 mm and approximately 1 mm.

6. The optical lens according to claim 1, wherein, The tilt magnitude error is less than about 60 μrad, and the average displacement surface roughness Sa is less than about 6 nm.

7. An optical lens, the optical lens comprising: A lens substrate having opposite first and second main surfaces, at least one of the first and second main surfaces being curved, the lens substrate comprising a cyclic olefin copolymer; An optical film comprising at least 10 alternating first polymer layers and second polymer layers, each of the first polymer layer and the second polymer layer having an average thickness of less than about 500 nm. and An adhesive film, the adhesive film comprising an adhesive layer having a composition different from cycloolefin polymers and different from cycloolefin copolymers and having a refractive index in the range of 1.45 to 1.6, the adhesive film being disposed on the first major surface and bonding the optical film to the first major surface, and such that the average peel force for separating the optical film from the lens substrate is greater than about 100 g / in, while at least one outermost major surface of the optical film maintains a lower spatial frequency tilt magnitude error and a higher spatial frequency tilt magnitude error each less than about 100 μrad, the lower spatial frequency tilt magnitude error and the higher spatial frequency tilt magnitude error being determined from the surface profile filtered with a corresponding lower spatial frequency band-pass Fourier filter and a higher spatial frequency band-pass Fourier filter, the higher spatial frequency band-pass Fourier filter having band-edge wavelengths of W1 and W2, the lower spatial frequency band-pass Fourier filter having band-edge wavelengths of W3 and W4, 0.1 mm ≤ W1 < W2 ≤ W3 < W4 ≤ 10 mm, W2 ≥ 2W1, W4 ≥ 2W3, wherein the adhesive layer has a glass transition temperature not greater than 25 °C, and wherein the adhesive layer comprises ethylene vinyl acetate, styrene-butadiene rubber, or a (meth)acrylate comprising an acrylate group having a straight-chain alkyl chain with at least 4 carbons.

8. The optical lens according to claim 7, wherein W1 is about 0.1 mm, W2 and W3 are each about 0.3 mm, and W4 is about 1 mm.

9. The optical lens according to claim 7, wherein at least one outermost major surface of the optical film has an average displacement surface roughness Sa less than about 10 nm.

10. The optical lens according to claim 7, wherein at least one of the lower spatial frequency tilt magnitude error and the higher spatial frequency tilt magnitude error is less than about 60 μrad.

11. The optical lens according to any one of claims 1 to 10, wherein the optical film includes a first outermost layer facing the adhesive layer, the first outermost layer comprising polycarbonate.

12. The optical lens according to any one of claims 1 to 10, wherein the adhesive film includes an olefin substrate, an adhesive layer disposed on the olefin substrate and substantially coextensive with the olefin substrate, the adhesive layer facing the optical film.

13. The optical lens according to any one of claims 1 to 10, wherein the adhesive layer comprises a solvent-deposited polymer.

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