Optical film and optical lens including the same

Abstract

The optical film includes a polarizer including an absorption polarizer layer, an olefin layer disposed on the polarizer, and an adhesive layer disposed between the olefin layer and the polarizer and bonding them. For light incident substantially perpendicularly, for the first and second orthogonal polarization states, and for at least one wavelength in the wavelength range from about 420 nm to about 680 nm, the polarizer substantially transmits incident light having the first polarization state, but does not substantially transmit incident light having the second polarization state. The adhesive layer, the olefin layer, and the absorption polarizer layer are coextruded and co-stretched with each other. The olefin layer can have a main surface that is not structured on the side opposite to the polarizer. The optical lens includes a lens substrate and an optical film disposed on and substantially conforming to the main surface of the lens substrate, with the olefin layer facing the lens substrate.

Description

Technical Field

[0001] [Summary of the Invention] In some aspects, this specification provides an optical film including a polarizer including an absorption polarizer layer, an olefin layer disposed on the polarizer, and an adhesive layer disposed between the olefin layer and the polarizer that adheres the olefin layer and the polarizer. For light incident substantially perpendicularly, for the first and second orthogonal polarization states, for at least one wavelength in the wavelength range from about 420 nm to about 680 nm, the polarizer substantially transmits incident light having the first polarization state, but does not substantially transmit incident light having the second polarization state. The olefin layer includes a cyclic olefin copolymer, a cyclic olefin polymer, or a blend thereof. The olefin layer can have a major surface that is not structured on the side opposite the polarizer. The adhesive layer, the olefin layer, and the absorption polarizer layer are coextruded and co-stretched with each other.

[0002] In some aspects, this specification provides an optical film including a polarizer including an absorption polarizer layer disposed on a reflective polarizer, an olefin layer disposed on the polarizer, and an adhesive layer disposed between the olefin layer and the polarizer that adheres the olefin layer and the polarizer. The reflective polarizer includes a plurality of at least 10 alternating first and second polymer layers in total, and each first and second polymer layer has an average thickness of less than about 500 nm. The olefin layer includes a cyclic olefin copolymer, a cyclic olefin polymer, or a blend thereof. The olefin layer can include a major surface that is not structured on the side opposite the polarizer. The absorption polarizer layer, the reflective polarizer, or both are coextruded and co-stretched with the adhesive layer and the olefin layer.

[0003] In some aspects, the present specification provides an optical film including a polarizer including an absorption polarizer layer, an olefin layer disposed on the polarizer, and an ethylene copolymer layer disposed between the olefin layer and the polarizer and bonding the olefin layer and the polarizer. For light incident substantially perpendicularly, for the first and second orthogonal polarization states, for at least one wavelength in the wavelength range from about 420 nm to about 680 nm, the polarizer substantially transmits incident light having the first polarization state, but does not substantially transmit incident light having the second polarization state. The olefin layer includes a cyclic olefin copolymer, a cyclic olefin polymer, or a blend thereof. The ethylene copolymer, the olefin, and the absorption polarizer layer are coextruded and co-stretched with each other.

[0004] In some aspects, the present specification provides an optical film including a polarizer including an absorption polarizer layer disposed on a plurality of alternating first and second polymer layers having a total of at least 10. Each of the first and second polymer layers has an average thickness of less than about 500 nm. An ethylene copolymer layer is disposed on the polarizer. The absorption polarizer layer, the plurality of alternating first and second polymer layers, or both are coextruded and co-stretched with the ethylene copolymer layer.

[0005] In some aspects, the present specification provides an optical lens including a lens substrate and the optical film described herein disposed on a main surface of the lens substrate and substantially conforming to the main surface of the lens substrate, with the olefin layer of the optical film facing the lens substrate.

[0006] In some aspects, the present specification provides a method for manufacturing an optical lens. The method includes providing an optical film. The optical film includes a polarizer including an absorption polarizer layer, an olefin layer disposed on the polarizer, and an adhesive layer disposed between the olefin layer and the polarizer to bond the olefin layer and the polarizer. For light incident substantially perpendicularly, for the first and second orthogonal polarization states, for at least one wavelength in the wavelength range from about 420 nm to about 680 nm, the polarizer substantially transmits the incident light having the first polarization state, but does not substantially transmit the incident light having the second polarization state. The olefin layer includes a cyclic olefin copolymer, a cyclic olefin polymer, or a blend thereof. Providing the optical film includes coextruding and co-stretching at least one of the olefin layer, the adhesive layer, and the polarizer layer. The method includes molding a lens substrate on the optical film such that the lens substrate faces and adheres to the olefin layer. The lens substrate can include an olefin composition.

[0007] These and other aspects will become apparent from the following detailed description. However, this brief summary should not be construed as limiting the claimed subject matter.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0009] In the following description, reference is made to the accompanying drawings which form a part hereof, and in which are shown various embodiments. It should be noted that the drawings are not necessarily to scale. Other embodiments are also contemplated and can be made without departing from the scope or spirit of this specification. Accordingly, the following detailed description should not be construed in a limiting sense.

[0010] An optical system can include one or more optical lenses including an optical film disposed on a lens substrate. For example, the optical system described in U.S. Patent No. 9,557,568 (Ouderkirk et al.) includes an optical lens having an optical film (e.g., a polarizing film) disposed on a lens substrate. In some embodiments, the lens substrate is desirably formed at least in part from an olefin such as a cyclic olefin copolymer (COC) or cyclic olefin polymer (COP) due to the low birefringence of such materials. However, with typical materials used for optical films (e.g., polyester), it can be difficult to achieve sufficient adhesion to such a lens substrate. According to some embodiments, it has been found that an optical film including a polarizer can include an outer layer that adheres well to such a lens substrate and an additional adhesive layer that adheres the outer layer to other layers of the polarizer. According to some embodiments, it has been found that by selecting the materials for the outer layer, the adhesive layer, and other layers of the optical film, the film can be formed, for example, by coextrusion and co-stretching.

[0011] Figures 1 to 8 are schematic cross-sectional views of an optical film according to some embodiments. The optical film 150 includes a polarizer 100 that can be an absorption polarizer layer or can include an absorption polarizer layer. The absorption polarizer layer can include a (e.g., dichroic) dye dispersed in a polymer. In FIG. 1, the polarizer 100 is a single layer and can be an absorption polarizer layer, but the polarizer 100 can optionally also include other layers. The optical film 150 can include an adhesive layer 26 that can be an ethylene copolymer layer, and can also include an olefin layer 28 disposed on the adhesive layer 26 as schematically shown in FIGS. 2 to 8. In FIG. 2, the polarizer 100 includes an absorption polarizer layer 120 disposed between optional protective layers 24 and 24'. In FIG. 3, the polarizer 100 includes a plurality 20 of alternating first (21) and second (22) polymer layers disposed on a first protective layer 24. In some embodiments, the optical film 150 includes an olefin layer 28 disposed on a first protective layer 24 opposite the plurality 20 of alternating first and second polymer layers, and includes an adhesive layer 26 between the olefin layer 28 and the first protective layer 24 that adheres the olefin layer 28 and the first protective layer 24. In some embodiments, at least one of the layers 21, 22, and 24 is an absorption polarizer layer. For example, the plurality 20 of layers 21, 22 can alternately include a high refractive index layer (e.g., 21) and a low refractive index layer (e.g., 22), and the high refractive index layer can include an absorption polarizer dye, for example, as described in U.S. Patent No. 10,928,571 (Haag et al.). Other suitable multilayer films including an absorption polarizer layer are described, for example, in U.S. Patent Nos. 10,466,398 (Johnson et al.), 10,838,127 (Haag et al.), and 11,022,734 (Stover et al.). The polarizer 100 can include a plurality of packets of alternating layers 21, 22, as schematically shown in FIG. 4, where each packet is separated by at least one layer thicker than each layer of layers 21, 22.

[0012] In some embodiments, for example, as schematically shown in FIGS. 5 to 8, the polarizer 100 includes an absorption polarizer layer 120, and further includes a plurality 20 of alternating first and second polymer layers 21, 22 disposed on the absorption polarizer 120. The polarizer 100 may be adhesively bonded, optionally with an adhesive layer 33, to a plurality 20 of alternating first and second polymer layers 21, 22 that may be disposed between protective layers 24'', 24''', as schematically shown in FIGS. 5 and 7, for example. Alternatively, for example, as schematically shown in FIGS. 6 and 8, the absorption polarizer layer 120 and the plurality 20 of alternating first and second polymer layers 21, 22 may be integrally formed with each other (e.g., co-extruded and co-stretched with each other). The polarizer 100 may include a reflective polarizer. For example, the plurality 20 of alternating first and second polymer layers 21, 22 may be a reflective polarizer, or the plurality 20 of alternating first and second polymer layers 21, 22 and the adjacent protective layers 24, 24' may together be a reflective polarizer. In some embodiments, the polarizer 100 includes a multilayer reflective polarizer 20, or 20 having an adjacent protective layer, adhesively bonded (directly or indirectly via an intermediate layer) to the absorption polarizer layer 120 with an adhesive layer 33. The absorption polarizer layer 120 may be disposed between the multilayer reflective polarizer and the olefin layer 28, as schematically shown in FIG. 5 (or FIG. 6 if the adhesive layer 33 is omitted), for example. Alternatively, the multilayer reflective polarizer may be disposed between the absorption polarizer layer 120 and the olefin layer 28, as schematically shown in FIG. 7 (or FIG. 8 if the adhesive layer 33 is omitted), for example. In some embodiments, the adhesive layer 26, the olefin layer 28, and the reflective polarizer 20 (or 20 having an adjacent protective layer) are co-extruded and co-stretched with each other. The reflective polarizer 20 is disposed between the absorption polarizer layer 120 and the olefin layer 28, and the adhesive layer 33 adhesively bonds the absorption polarizer layer 120 to the reflective polarizer 20 (directly or indirectly). In some embodiments, the olefin layer 28 and the absorption polarizer layer 120 are co-extruded and co-stretched with each other.The absorption polarizer layer 120 is disposed between the reflective polarizer 20 and the olefin layer 28, and an adhesive layer adhesively attaches (either directly or indirectly) the reflective polarizer 20 to the absorption polarizer layer 120.

[0013] In some embodiments, each of the first and second polymer layers 21, 22 has an average thickness of less than about 500, 400, 350, 300, 250, or 200 nanometers. The average thickness can be, for example, at least about 20 nanometers or at least about 40 nanometers. For example, in some embodiments, each of the first and second polymer layers can have an average thickness in the range of from about 20 nanometers to about 500 nanometers or from about 40 nanometers to about 400 nanometers. In some embodiments, the first protective layer 24 (and / or other protective layers) has, for example, an average thickness greater than about 750, 1000, 1500, or 2000 nanometers. The average thickness of the first protective layer 24 can be, for example, up to about 30 micrometers or about 20 micrometers. In some embodiments, the absorption polarizer layer 120 has, for example, an average thickness greater than about 750, 1000, 1500, or 2000 nanometers. The average thickness of the absorption polarizer layer 120 can be, for example, up to about 30 micrometers or about 20 micrometers. In some embodiments, for example, each of the first and second polymer layers has an average thickness of less than about 500 nanometers and the first protective layer has an average thickness greater than about 750 nanometers. In some embodiments, the adhesive layer 26 has an average thickness in the range of from about 0.5 to 20 micrometers, or from about 1 to 10 micrometers, or from about 1.5 to 8 micrometers. In some embodiments, the adhesive layer 26 has an average thickness greater than the average thickness of each of the first and second polymer layers. In some embodiments, the adhesive layer 26 has an average thickness greater than the average thickness of the first protective layer 24. In some embodiments, the olefin layer 28 has an average thickness within any of the ranges described for the adhesive layer 26 or the protective layer.

[0014] In some embodiments, the plurality of alternating first and second polymer layers total at least 10, 20, 50, 75, 100, 150, 200, 250, 300, 350, or 400. The plurality of alternating first and second polymer layers are, for example, at most 1500 or 1000 in total. For example, the plurality of alternating first and second polymer layers 21, 22 are from 10 to 1500 or from 20 to 1000 in total.

[0015] The optical film 150 can include additional layers. For example, the optical film can include a second protective layer 24' disposed on the opposite side of the first protective layer 24 from the plurality of alternating layers 21, 22. The optical film can further include one or more additional layers 25 disposed between some of the plurality of alternating layers 21, 22, as schematically shown in FIG. 4. One or more of the additional layers 25 (and layers 24, 24', 24'', 24''') can be protective boundary layers, as will be understood by those skilled in the art. At least one of the layers 25, 24, 24', 24'', 24''' can be an absorption polarizer layer. Each of the one or more additional layers 25 and / or the protective layers 24', 24'', 24''' can have any average thickness within the range described for the first protective layer 24.

[0016] In some embodiments, the adhesive layer 26 includes a plurality of sub-layers. For example, the adhesive layer 26 can include a sub-layer 26a for adhering to the olefin layer 28 and a sub-layer 26b for adhering to the first protective layer 24, as schematically shown in FIG. 4. The plurality of sub-layers can include only two sub-layers or more than two sub-layers. In some embodiments, the adhesive layer 26 can be a single monolithic layer that directly contacts the olefin layer 28 and the polarizer 100.

[0017] In some embodiments, the olefin layer 28 has a major surface 281 that is not structured on the side opposite the polarizer 100. The unstructured major surface generally does not include structures (e.g., microstructures) created on the surface for, e.g., optical or mechanical purposes, but can include marks and other features resulting from normal manufacturing processes. The unstructured major surface can be characterized in terms of surface roughness (e.g., the average peak-to-valley surface roughness, generally denoted as Rz) and / or haze. In some embodiments, the unstructured major surface 281 has an average peak-to-valley surface roughness Rz of less than about 2, 1.5, 1, 0.5, 0.4, 0.3, 0.2, or 0.1 micrometers. Rz can be as low as, for example, about 70, 60, 50, 40, 30, or 20 nanometers. In some embodiments, the optical film 150 has a transmission haze of less than about 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, or 1 percent. The transmission haze can be measured, for example, in accordance with the ASTM D1003-13 test standard.

[0018] The protective layer can have the same composition as either the first or second polymer layer. Suitable materials for the various layers include, for example, polyethylene naphthalate (PEN), coPEN (copolyethylene naphthalate terephthalate copolymer), polyethylene terephthalate (PET), polyhexyl ethylene naphthalate copolymer (PHEN), syndiotactic polystyrene (sPS), glycol-modified PET (PETG), glycol-modified PEN (PENG), coPET-polycarbonate alloy, various other copolyesters described elsewhere in this specification, polyolefins, polymethyl methacrylate (PMMA), coPMMA (copolymer of methyl methacrylate and ethyl acrylate), other acrylates, or blends thereof. For the various layers, other suitable materials include, for example, those described in U.S. Patent Nos. 5,103,337 (Schrenk et al.), 5,540,978 (Schrenk), 5,882,774 (Jonza et al.), 6,179,948 (Merrill et al.), 6,207,260 (Wheatley et al.), 6,783,349 (Neavin et al.), 6,967,778 (Wheatley et al.), 9,069,136 (Weber et al.), and 9,162,406 (Neavin et al.).

[0019] In some embodiments, at least one of the first and second polymer layers comprises a polymer comprising naphthalate groups (e.g., PEN or coPEN). In some embodiments, at least one of the first and second polymer layers comprises a polymer comprising terephthalate groups (e.g., PET or coPET). In some embodiments, the first polymer layer is birefringent and the second polymer layer is substantially optically isotropic. The birefringent layer can comprise a polymer comprising naphthalate groups and / or terephthalate groups. The substantially isotropic layer can comprise, for example, a polyester, copolyester, or polycarbonate / copolyester alloy. Additionally or alternatively, the protective layer can be formed from any of these materials. Such materials have been found to adhere well to an adhesive layer that adheres well to the olefin layer described elsewhere in this specification.

[0020] The absorption polarizer layer is a polymer layer containing or capable of containing aligned dye molecules 121 dispersed in the polymer layer. The dye molecules 121 can be dichroic dyes available from Mitsui Chemicals Fine (Japan). Examples of dichroic dyes available from Mitsui Chemicals Fine include PD-325H, PD-335H, PD-104, and PD-318H. The aligned dye molecules 121 can be substantially uniformly dispersed in the polymer of the polymer layer. The polymer can be any of the polymers described for the alternating first and second layers and the protective layer. In some embodiments, the polymer is birefringent (e.g., the polarizer layer can be stretched to align the dye molecules and polymer molecules in the stretching direction). In some embodiments, the polymer is substantially optically isotropic (e.g., the polarizer layer is stretched to align the dye molecules, but can be heated to a high enough temperature so that the polymer does not retain birefringence). In some embodiments, the polymer is PEN, coPEN, PET, or coPET. In some embodiments, the polarizer 100 includes at least one protective layer disposed on the absorption polarizer layer. The protective layer can be, for example, a polycarbonate / copolyester alloy layer. In some embodiments, the polarizer 100 includes a PEN or coPEN layer disposed between polycarbonate / copolyester alloy layers, and the PEN or coPEN layer contains dichroic dyes dispersed therein.

[0021] Any of the birefringent layers can have a maximum birefringence (e.g., the absolute value of the refractive index difference in the x and z directions) exceeding, for example, about 0.05, 0.08, 0.1, 0.12, or 0.15 at a first wavelength within the wavelength range from about 400 nm to about 700 nm (e.g., 532 nm, 550 nm, or 633 nm). Any of the substantially isotropic layers can have a maximum birefringence of less than, for example, about 0.025, 0.02, 0.015, 0.01, or 0.005 at the first wavelength. The birefringent layer can have a refractive index that is, at least at the first wavelength, for example, at least about 0.05, 0.08, 0.1, 0.12, or 0.15 higher than the refractive index of the substantially isotropic layer in at least one direction. The maximum difference in refractive index in the same direction between different layers, or the maximum difference in refractive index in different directions within the same layer, can be, at the first wavelength, for example, up to about 0.5, 0.4, or 0.3. For optically absorptive layers, unless otherwise specified, the refractive index refers to the real part of the complex refractive index.

[0022] In some embodiments, the adhesive layer 26 has a glass transition temperature (Tg) of less than about -100°C or less than about -120°C. In some such embodiments, or in other embodiments, the adhesive layer has a melting point that exceeds about 80°C, or exceeds about 100°C, or exceeds about 120°C. For example, the adhesive layer 26 can have a glass transition temperature of less than about -100°C and a melting point that exceeds about 80°C or exceeds about 100°C. As another example, the adhesive layer 26 can have a glass transition temperature of less than about -120°C and a melting point that exceeds about 100°C or exceeds about 120°C. In some embodiments, the olefin layer 28 has a glass transition temperature in the range of 100°C to 115°C, or in the range of 105°C to 110°C. By setting the Tg of the olefin layer 28 within these ranges, the processability of the film is improved. For example, in some processing methods, if the Tg is too low, the film may stick to the tenter clips, and if the Tg is too high, the film may not be oriented in the desired direction and the desired optical properties cannot be obtained. The glass transition temperature can be measured, for example, by differential scanning calorimetry according to the ASTM E1356-08 (reapproved in 2014) standard.

[0023] In some embodiments, the adhesive layer 26 (and / or other layers of the optical films 150, 150') has a weight average molecular weight that exceeds about 20,000, 30,000, 40,000, or 50,000 Daltons, or is within the ranges described elsewhere herein. In some embodiments, the composition of the adhesive layer 26 is different from the respective compositions of the first protective layer 24 and the first and second polymer layers 21 and 22. The adhesive layer 26 can be or include an ethylene copolymer. The ethylene copolymer can include, for example, one or more of a styrene group, an acrylic group, a vinyl group, or a maleic anhydride group. Suitable ethylene copolymers include, for example, those available under the trade name KRATON from KRATON Corporation (Houston, TX), and those available under the trade names BYNEL and ELVALOY from Dow Chemical (Midland, MI). The adhesive layer 26 can be or include, for example, a PETG layer. Suitable PETG includes, for example, GN071 available from Eastman Chemical (Kingsport, TN).

[0024] In some embodiments, the optical films 150, 150' include an ethylene copolymer layer 26 disposed over the first protective layer 24 on the opposite side of the plurality 20 of alternating first and second polymer layers 21 and 22. In some embodiments, the optical film 150 further includes an olefin layer 28, and the ethylene copolymer layer 26 adheres the olefin layer and the first protective layer to each other. The ethylene copolymer layer 26 can include an ethylene copolymer further described elsewhere herein.

[0025] The olefin layer 28 can include, for example, cyclic olefin copolymer (COC), cyclic olefin polymer (COP), or blends thereof. Olefin polymers and copolymers suitable for the olefin layer 28 and / or the lens substrate 220 (see, e.g., FIG. 3) include, for example, those available under the trade name TOPAS from TOPAS Advanced Polymers GmbH (Rauenheim, Germany) and those available under the trade name ZEONOR from Zeon Specialty Materials, Inc. (Sunnyvale, CA).

[0026] The materials of the various layers can be selected to provide a high peel force. In some embodiments, the optical film has an average peel force greater than about 100, 200, 300, 500, 1000, 1500, 2000, 3000, 4000, 4500, or 5000 g / in. In some embodiments, the peel force is so high that a layer of 1-inch-wide film strip cannot be peeled even using a 10-pound load cell. The peel force is measured using a 90-degree peel at a draw rate of 12 inches per minute unless otherwise specified. In some embodiments, the optical film having an average peel force within any of these ranges is formed from a plurality of alternating first and second polymer layers disposed on a first protective layer and includes an adhesive layer disposed on the first protective layer on the opposite side of the plurality of alternating first and second polymer layers. Each of the first polymer layers includes a polymer containing a naphthalate group and / or a terephthalate group. Each of the first protective layer and the second polymer layer includes a polyester, a copolyester, or a polycarbonate / copolyester alloy. The adhesive layer includes an ethylene copolymer. The polyester, copolyester, or polycarbonate / copolyester alloy of the first protective layer can have the same or a different composition from the polyester, copolyester, or polycarbonate / copolyester alloy of the second polymer layer. The ethylene copolymer can include one or more of a styrene group, an acrylic group, a vinyl group, or a maleic anhydride group.

[0027] In some embodiments, each layer of the optical film 150 is formed from a thermoplastic polymer. The thermoplastic polymer can be selected to be easily extruded and processed. For example, the thermoplastic polymer can be selected to have a molecular weight and / or intrinsic viscosity and / or melt flow index (MFI) within a range suitable for extrudability. In some embodiments, each thermoplastic polymer has a weight average molecular weight Mw greater than 20,000 Daltons, or greater than 30,000 Daltons, or greater than 40,000 Daltons, or greater than 50,000 Daltons. The weight average molecular weight Mw can be, for example, up to 1,000,000 Daltons, or up to 600,000 Daltons, or up to 400,000 Daltons, or up to 200,000 Daltons, or up to 150,000 Daltons. In some such embodiments, or in other embodiments, each thermoplastic polymer has an intrinsic viscosity in the range of 0.3 dl / g to 1.2 dl / g, or in the range of 0.4 dl / g to 1.0 dl / g, as measured in a solvent blend containing 60 weight percent o-chlorobenzene and 40 weight percent phenol. In some such embodiments, or in other embodiments, the thermoplastic polymer has a melt flow index greater than 5 g / 10 min, or greater than 10 g / 10 min, or greater than 20 g / 10 min. The melt flow index can be, for example, up to 300 g / 10 min, or up to 200 g / 10 min, or up to 100 g / 10 min. The weight average molecular weight Mw can be measured, for example, using gel permeation chromatography. The intrinsic viscosity can be measured, for example, using a capillary viscometer. The melt flow index (also referred to as melt flow rate) can be measured, for example, using an extrusion plastometer in accordance with ASTM D1238-20.

[0028] In an embodiment where the optical film 150 includes an adhesive layer, an olefin layer, and an absorption polarizer layer, the adhesive layer, the olefin layer, and the absorption polarizer layer can be co-extruded and co-stretched with each other. The optical film is generally stretched after extrusion to orient the polymer of the polarizer layer and / or the dye molecules in the polarizer layer. In an embodiment where the optical film 150 further includes a plurality 20 of alternating first and second polymer layers, the plurality of alternating first and second polymer layers can be co-extruded and co-stretched with the olefin layer, the adhesive layer, and the absorption polarizer layer. In an embodiment where the optical film 150 includes an adhesive layer 26, an olefin layer 28, an absorption polarizer layer 120, and a reflective polarizer 20, the absorption polarizer layer, the reflective polarizer, or both (100 and 20) can be co-extruded and co-stretched with the adhesive layer and the olefin layer. In an embodiment where the optical film 150 includes an ethylene copolymer layer, an olefin layer, and an absorption polarizer layer, the ethylene copolymer layer, the olefin layer, and the absorption polarizer layer can be co-extruded and co-stretched with each other. In an embodiment where the polarizer further includes a plurality 20 of alternating first and second polymer layers, the plurality of alternating first and second polymer layers can be co-extruded and co-stretched with the olefin layer, the ethylene copolymer layer, and the absorption polarizer layer. In an embodiment where the optical film 150 includes an ethylene copolymer layer 26, an absorption polarizer layer 120, and a plurality 20 of alternating first and second polymer layers, the absorption polarizer layer, the plurality of alternating first and second polymer layers, or both (120 and 20) can be co-extruded and co-stretched with the ethylene copolymer layer.

[0029] The optical film 150 can be integrally formed. As used herein, when a first element is "integrally formed" with a second element, it means that the first and second elements are manufactured together, rather than being manufactured separately and then joined. Integral formation includes manufacturing the second element on top of the first element after manufacturing the first element. When an optical film including multiple layers is integrally formed, all the layers are manufactured together (e.g., combined as a melt stream and then cast onto a cooling roll to form a cast film having each layer, and then the cast film is oriented), rather than being manufactured separately and then joined. In some embodiments, all the layers of the optical film 150 are coextruded. In some embodiments, all the layers of the optical film 150 are further co-stretched.

[0030] As is known in the art, multilayer optical films including alternating polymer layers can be used to provide desired reflection and transmission in a desired wavelength range by appropriately selecting the differences in layer thickness and refractive index. 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.), 6,783,349 (Neavin et al.), 6,949,212 (Merrill et al.), 6,967,778 (Wheatley et al.), and 9,162,406 (Neavin et al.).

[0031] FIG. 9 is a schematic diagram showing the relationship between the transmittances 241 and 242 of light incident substantially perpendicular to a polarizer for orthogonal first and second polarization states 141 and 142 (see, e.g., FIG. 1) in some embodiments and the wavelength. The polarizer in FIG. 9 can be an absorption polarizer layer (e.g., layer 120), a reflective polarizer (e.g., corresponding to a plurality of alternating layers 20 having any protective boundary layer), a plurality of alternating first and second polymer layers (e.g., the plurality 20), or the polarizer 100. The polarizer has average optical transmittances T1 and T2 for each of the first and second polarization states 141 and 142 over a wavelength range from λ1 (e.g., 400 nm, 420 nm, or 450 nm) to λ1 (e.g., 7000 nm, 680 nm, or 650 nm). As will be understood by those skilled in the art, the shape of the transmittance curve may be different from that schematically shown in FIG. 9. In some embodiments, for orthogonal first and second polarization states 141 and 142, for at least one wavelength within a wavelength range from about 420 nm to about 680 nm (e.g., 532 nm, 560 nm, and / or 633 nm), the polarizer 100 substantially transmits incident light having the first polarization state but substantially does not transmit incident light having the second polarization state. In some embodiments, for light 140 (see, e.g., FIG. 1) incident substantially perpendicular (e.g., with an incident angle of less than about 30 degrees, 20 degrees, 10 degrees, or 5 degrees), for orthogonal first and second polarization states 141 and 142, and for at least one wavelength within a wavelength range from about 420 nm to about 680 nm, the polarizer 100 substantially transmits incident light having the first polarization state but substantially does not transmit incident light having the second polarization state. Substantially transmitting means that more than 50 percent of the light is transmitted. In some embodiments, for at least one wavelength, the polarizer transmits more than 50, 60, 70, 80, or 85 percent of the incident light having the first polarization state 141. In some embodiments, for at least one wavelength, the polarizer 100 transmits less than 50, 40, 30, 20, or 10 percent of the incident light having the first polarization state 141.In some embodiments, for light 140 incident substantially perpendicularly and a predetermined wavelength range (e.g., from 400 nm to 700 nm, or from 420 nm to 680 nm, or from 450 nm to 650 nm), each of the polarizer 100, the absorption polarizer layer 120, the reflective polarizer, the plurality of alternating layers 20, the absorption polarizer layer 120 and the reflective polarizer, or the absorption polarizer layer 120 and the plurality of alternating layers 20 has an average optical transmittance T1 of more than 50 percent with respect to the first polarization state 141 and an average optical transmittance of less than 50 percent with respect to the second polarization state 142. The average optical transmittance T1 with respect to the first polarization state 141 can be, for example, more than 50, 60, 70, 80, or 85 percent. The average optical transmittance T2 with respect to the second polarization state 142 can be, for example, less than 50, 40, 30, 20, or 10 percent.

[0032] In some embodiments, the optical film 150 is an absorption polarizer. In some embodiments, the optical film 150 is a hybrid reflective absorption polarizer. The difference between 100% and T1 or T2 is the percentage of the incident light reflected and absorbed by the polarizer. In some embodiments, the absorption polarizer layer 120 absorbs at least 10, 20, 30, 40, 50, 60, 70, 80, 85, or 90% of the incident light with respect to at least one wavelength and the second polarization state 142. In some embodiments, the absorption polarizer layer 120 has a dichroic ratio of at least about 5, 10, 15, or 20. The dichroic ratio is generally understood as the ratio of the absorption constant in the block polarization state 142 to the absorption constant in the pass polarization state 141 and can be determined with respect to at least one wavelength in the wavelength range from about 420 nm to about 680 nm or as the average dichroic ratio in the wavelength range from about 420 nm to about 680 nm.

[0033] In embodiments where the reflective polarizer and the absorptive polarizer layer are coextruded and co-stretched with each other, the transmission axis of the reflective polarizer (e.g., the y-axis, or the axis along the polarization state 141, or the axis along which the transmission of substantially perpendicularly incident light polarized along the axis is highest) and the blocking axis (e.g., the x-axis, or the axis along the polarization state 142, or the axis along which the transmission of substantially perpendicularly incident light polarized along the axis is lowest) are generally well-aligned (e.g., within about 5 degrees, 4 degrees, 3 degrees, 2 degrees, or 1 degree) with the corresponding transmission axis and blocking axis of the absorptive polarizer. In embodiments where the reflective polarizer and the absorptive polarizer layer are formed separately and adhered to each other, it is generally desirable for the respective transmission axes and blocking axes to be properly aligned (e.g., within about 15 degrees, 12 degrees, 10 degrees, 8 degrees, 5 degrees, 4 degrees, 3 degrees, 2 degrees, or 1 degree). For example, the absorptive polarizer layer has a first blocking axis, the reflective polarizer has a second blocking axis, and the first and second blocking axes can be substantially parallel to each other or parallel within about 15 degrees, 12 degrees, 10 degrees, 8 degrees, 5 degrees, 4 degrees, 3 degrees, 2 degrees, or 1 degree.

[0034] FIG. 10 is a schematic cross-sectional view of an optical lens 200 according to some embodiments. The optical lens 200 includes a lens substrate 220 and any optical film 250 (e.g., corresponding to the optical film 150) described herein, and the optical film 250 is disposed on and substantially conforms to the main surface 221 of the lens substrate 220. The optical film 250 can substantially conform to the main surface when the lens is molded (e.g., injection molded) over the optical film and the optical film conforms to the main surface to normal manufacturing variations. The olefin layer 28 and / or the ethylene copolymer layer can face the lens substrate 220 (e.g., refer to the x-y-z coordinate system schematically shown in FIGS. 1-8). In some embodiments, the lens substrate 220 includes an olefin composition. The olefin composition can be or include a cyclic olefin polymer (COP), a cyclic olefin copolymer (COP), or a blend thereof. In some such embodiments or in other embodiments, the olefin layer 28 adheres the optical film 250 to the lens substrate 220.

[0035] FIG. 11 is a schematic diagram of a method for manufacturing an optical lens according to some embodiments. This method includes providing an optical film 250, which may be the same as the optical film 150 described elsewhere in this specification. For example, the optical film 250 can include a polarizer 100 including an absorption polarizer layer 120, an olefin layer 28 disposed on the polarizer 100, and an adhesive layer 26 disposed between and bonding the olefin layer 28 and the polarizer 100. This method includes molding a lens substrate 220 onto the optical film 250 such that the lens substrate 220 faces and adheres to the olefin layer 28. The lens substrate can include an olefin composition. The olefin layer can include a cyclic olefin copolymer, a cyclic olefin polymer, or a blend thereof. In some embodiments, providing the optical film includes coextruding and co-stretching at least one layer of the olefin layer, the adhesive layer, and the polarizer. In some embodiments, at least one layer of the polarizer includes an absorption polarizer layer. In some embodiments, the polarizer includes a total of at least 10 alternating first and second polymer layers, each of the first and second polymer layers having an average thickness of less than about 500 nm. In some such embodiments, at least one layer of the polarizer includes a plurality of alternating first and second polymer layers. Providing the optical film 250 includes coextruding and co-stretching all layers of the optical film. Molding the lens substrate 220 onto the optical film 250 can include an insert molding process. Briefly, the optical film 250 is placed adjacent to the surface of the upper mold part 460, and a resin 483 (e.g., a molten olefin composition) is injected into the cavity between the optical film 250 and the lower mold part 470 (e.g., through a gate 465). Appropriate insert molding processes are known to those skilled in the art. Details of appropriate insert molding processes are described, for example, in U.S. Patent Application Publication No. 2021 / 0208320 (Ambur et al.) and U.S. Patent No. 11,065,855 (Klun et al.).

Examples

[0036] All parts and percentages in the examples are by weight unless otherwise specified. Reagents and solvents are available from MILLIPORE-SIGMA (Burlington, Massachusetts) unless otherwise specified. [Table 1]

[0037] For some film samples, two sets of films having an ABCBA layer structure were made by coextrusion and subsequent co-stretching. These films showed that when the A layer is formed from an olefin and the C layer is formed from a polyester commonly used in multilayer optical films, a material coextrudable / co-stretchable for the B layer can be selected. For example, films containing an absorption polarizer layer, and / or films having a structure of ABC’DCDCDC… (where C’ is a protective layer (e.g., a protective boundary layer), and for example, when alternating D and C layers are adapted to reflect light mainly by optical interference, and / or when the D or C layer contains an absorption polarizing dye, etc.) can be made in the same way.

[0038] The first set of films having an ABCBA structure was produced by the following procedure. The outer (A) layer was manufactured by extruding the resin through a 27 mm twin screw extruder (TSE) and feeding it through a neck tube and a gear pump into a 5-layer feed block and die. This melt train used a progressive temperature extrusion profile with a maximum temperature of 270 °C. The adhesive (B) layer was manufactured by extruding the resin through a 27 mm TSE with a progressive temperature profile that peaks at 260 °C or near it and feeding it through a neck tube and a gear pump into a 5-layer feed block. The core (C) layer was manufactured by extruding the above resin through a 27 mm TSE with a progressive temperature profile that peaks at 270 °C or near it and feeding it through a neck tube and a gear pump into a 5-layer feed block. The feed block / die was maintained at a target temperature of 270 °C, and the casting wheel was operated between 50 °C and 70 °C. The film materials are shown in the following table. The feed rate for each TSE was 10 pounds per hour, but a feed rate of 14.4 pounds per hour was used for the C layer of sample 10. In the case of blends, the parts by weight are shown in parentheses.

Table 2

[0039] Various film samples were oriented and annealed in a two-stage KARO IV laboratory stretching device (available from Bruckner Maschinenbau, Siegsdorf, Germany) using the following procedure. The cast web film was conveyed into an oven at various temperatures shown in the following table, held for 60 seconds, and then stretched at several different ratios shown in the following table (when the draw ratio is shown as x×X, the oriented region of the film is x×X longer than the initial film in each direction). The film was then removed from the KARO and evaluated. The transmission haze was measured using a Haze-Gard i haze meter available from BYK Instruments.

[0040] The transmission haze (percent) of the film samples stretched at a draw ratio of 1×5 is reported in the following table. [Table 3]

[0041] The transmission haze (percent) of the film samples stretched at a draw ratio of 1×5.5 is reported in the following table. [Table 4]

[0042] The transmission haze (percent) of the film samples stretched at a draw ratio of 1×6 is reported in the following table. [Table 5]

[0043] The transmission haze (percent) of the film samples stretched at the specified draw ratio and annealed at 215°C for 15 seconds is reported in the following table. [Table 6]

[0044] The transmission haze (percent) of the non-annealed film samples and the corresponding samples annealed at 215°C for 15 seconds is reported in the following table. [Table 7]

[0045] The transmission haze (percent) of the film samples biaxially stretched at the specified draw ratio is reported in the following table. [Table 8]

[0046] The transmission haze (percent) of film samples biaxially stretched at a specified draw ratio and annealed at 215 °C for 15 seconds is reported in the following table.

Table 9

[0047] A second set of films having an ABCBA structure was made, for example, to examine the effect of the composition of the A layer (e.g., the effect of the glass transition temperature of the COC blend) on the optical and adhesion properties. Film samples were made using the resins shown in the following table by the method generally described above. The feed rate for each TSE of each sample was 10 pounds per hour.

Table 10

[0048] The glass transition temperature (Tg) of the A layer was obtained using a differential scanning calorimeter (DSC). The DSC used a heating / cooling / heating cycle. Each sample was weighed and placed in the DSC. The following method was used. Method log: 1: Data storage: Off 2: Equilibrate at -70.00 °C 3: Isothermal for 5.00 minutes 4: Data storage: On 5: Heat up to 200.00 °C at 20.00 °C / min 6: Mark the end of cycle 1 7: Data storage: Off 8: Equilibrate at 200.00 °C 9: Isothermal for 5.00 minutes 10: Data storage: On 11: Cool down to -70.00 °C at 20.00 °C / min 12: Mark the end of cycle 2 13: Data storage: Off 14: Equilibrate at -70.00 °C 15: Modulate + / -1.00 °C every 60 seconds 16: Isothermal for 5.00 minutes 17: Data storage: On 18: Heat up to 200.00 °C at 3.00 °C per minute 19: Mark the end of cycle 3 20: Data storage: Off 21: End of method

[0049] Tg is measured at the inflection point of the bulge during the second heating cycle starting from step 18, which is what those skilled in the art recognize as Tg. The obtained Tg is reported in the following table.

Table 11

[0050] Film samples were uniaxially oriented on a two-stage KARO lab stretching device using the following procedure. The cast web film was transported to ovens at various temperatures, held for 60 seconds, and then stretched at several different ratios. The film was then removed from the KARO and haze was evaluated as described above. The obtained transmission haze (percent) for various draw ratios and oven temperatures is shown in the following table.

Table 12

Table 13

[0051] The peel force of various cast film samples was measured using an IMASS SP-2100 equipped with a 10-pound load cell. The film was cut into 1-inch-wide samples and laminated to glass with double-sided tape. The glass was loaded into an IMASS holder and 90-degree peel was measured. The draw rate was set at 12 inches per minute, and after a 2-second delay, the force was averaged over 5 seconds. This was repeated 4 times. The average value was taken and reported. The following table reports the peel force data for these films. Many films showed a peel force that was impossible to peel or so high that separation of the film stack did not occur in end-use applications.

Table 14

[0052] Terms such as “about” are used in this specification and shall be understood by those skilled in the art in the context in which they are described. When the use of “about” applied to quantities representing the size, amount, and physical characteristics of features is not clear to those skilled in the art in the context in which it is used and described in this specification, “about” shall be understood to mean within 10% of the specified value. A quantity given as “about” a specified value can be the precisely specified value. For example, when not clear to those skilled in the art in the context in which it is used and described in this specification, a quantity having a value of “about 1” means that the quantity has a value between 0.9 and 1.1 and that value can be 1.

[0053] Terms such as “substantially” are used in this specification and shall be understood by those skilled in the art in the context in which they are described. When the use of “substantially” with respect to a property or feature is not clear to those skilled in the art in the context in which it is used and described in this specification, and when the opposite meaning of that property or feature is clear to those skilled in the art, “substantially” shall be understood to mean that the property or feature is shown to a greater extent than its opposite property or feature.

[0054] All of the foregoing references, patents, and patent applications are hereby incorporated by reference in their entirety in a consistent manner. In the event of any conflict or contradiction between the incorporated reference portions and this application, the information of the foregoing description shall prevail.

[0055] The description of elements in the figures is understood to apply equally to corresponding elements in other figures, unless otherwise noted. Although specific embodiments are illustrated and described herein, those skilled in the art will understand that various alternative and / or equivalent implementations may be substituted for the specific embodiments presented and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations, variations, or combinations of the specific embodiments discussed herein. Accordingly, the present disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. A polarizer including an absorption polarizer layer, an olefin layer disposed on the polarizer, and an adhesive layer disposed between the olefin layer and the polarizer to adhere the olefin layer and the polarizer, wherein the polarizer substantially transmits incident light having the first polarization state with respect to light incident substantially perpendicularly, with respect to the first and second orthogonal polarization states, and with respect to at least one wavelength in the wavelength range from about 420 nm to about 680 nm, while substantially not transmitting incident light having the second polarization state, the olefin layer includes a cyclic olefin copolymer, a cyclic olefin polymer, or a blend thereof, and the olefin layer has a major surface that is not structured on the side opposite to the polarizer, an optical film in which the adhesive layer, the olefin layer, and the absorption polarizer layer are coextruded and co-stretched with each other.

2. The optical film according to claim 1, wherein the polarizer further includes a plurality of alternating first and second polymer layers disposed on the absorption polarizer layer, and each of the first and second polymer layers has an average thickness of less than about 500 nm.

3. The optical film according to claim 2, wherein the plurality of alternating first and second polymer layers are coextruded and co-stretched together with the olefin layer, the adhesive layer, and the absorption polarizer layer.

4. The optical film according to claim 1, wherein the absorption polarizer layer has a polymer layer containing oriented dye molecules dispersed inside the polymer layer.

5. The optical film according to claim 1, wherein the unstructured major surface has an average peak-to-valley surface roughness Rz of less than about 1 micrometer.

6. The optical film according to claim 1, having a transmission haze of less than about 5 percent.

7. The optical film according to claim 1, wherein the adhesive layer has a glass transition temperature of less than about -100 °C and a melting point of greater than about 80 °C.

8. A polarizer including an absorption polarizer layer disposed on a reflective polarizer, an olefin layer disposed on the polarizer, and an adhesive layer disposed between the olefin layer and the polarizer to adhere the olefin layer and the polarizer, wherein the reflective polarizer includes a total of at least 10 alternating first and second polymer layers, and each of the first and second polymer layers has an average thickness of less than about 500 nm. The olefin layer includes a cyclic olefin copolymer, a cyclic olefin polymer, or a blend thereof, and the olefin layer has a major surface that is not structured on the side opposite the polarizer. An optical film in which the absorption polarizer layer, the reflective polarizer, or both are coextruded and co-stretched with the adhesive layer and the olefin layer. **Claim 9** The optical film according to claim 8, wherein all layers of the optical film are coextruded and co-stretched with each other. **Claim 10** A polarizer including an absorption polarizer layer, an olefin layer disposed on the polarizer, and an ethylene copolymer layer disposed between the olefin layer and the polarizer and bonding the olefin layer and the polarizer. The polarizer substantially transmits incident light having the first polarization state with respect to light incident substantially perpendicularly, with respect to first and second orthogonal polarization states, and with respect to at least one wavelength in the wavelength range of about 420 nm to about 680 nm, but does not substantially transmit incident light having the second polarization state. The olefin layer includes a cyclic olefin copolymer, a cyclic olefin polymer, or a blend thereof. An optical film in which the ethylene copolymer layer, the olefin layer, and the absorption polarizer layer are coextruded and co-stretched with each other. **Claim 11** A polarizer including an absorption polarizer layer disposed on a plurality of alternating first and second polymer layers, in total at least 10, and an ethylene copolymer layer disposed on the polarizer. Each of the first and second polymer layers has an average thickness of less than about 500 nm. An optical film in which the absorption polarizer layer, the plurality of alternating first and second polymer layers, or both are coextruded and co-stretched with the ethylene copolymer layer. **Claim 12** The optical film according to claim 11, further comprising an olefin layer, wherein the ethylene copolymer layer bonds the olefin layer and the polarizer to each other. **Claim 13** An optical lens comprising a lens substrate and the optical film according to any one of claims 1 to 10 or 12, wherein the optical film is disposed on a major surface of the lens substrate and substantially conforms to the major surface of the lens substrate, and the olefin layer faces the lens substrate. **Claim 14** An optical film, comprising: a polarizer including an absorption polarizer layer; an olefin layer disposed on the polarizer; and an adhesive layer disposed between the olefin layer and the polarizer to bond the olefin layer and the polarizer, wherein the polarizer substantially transmits incident light having the first polarization state with respect to light incident substantially perpendicularly, with respect to the first and second orthogonal polarization states, and with respect to at least one wavelength in the wavelength range from about 420 nm to about 680 nm, but does not substantially transmit incident light having the second polarization state, and the olefin layer includes a cyclic olefin copolymer, a cyclic olefin polymer, or a blend thereof, and a step of providing the optical film. A step of forming a lens substrate on the optical film such that the lens substrate faces the olefin layer and adheres to the olefin layer. The lens substrate includes an olefin composition. The step of providing the optical film includes co-extruding and co-stretching at least one layer of the olefin layer, the adhesive layer, and the polarizer. A method for manufacturing an optical lens.

15. The manufacturing method according to claim 14, wherein at least one layer of the polarizer includes the absorption polarizer layer.

Images