Polarizing PVA flakes for reducing optical distortion

Abstract

The present disclosure relates to a polarizing sheet comprising the following stacked on each other in the following order: A1) a thermoplastic film, B) a PVA polarizing film, A2) a thermoplastic film, A1) and A2) being the same or different, the thickness of A1) and the thickness of A2) being the same or different, and wherein: the thickness of A1) and the thickness of A2) are each less than or equal to 80 [mu] m, and the thickness of B) is less than or equal to 40 [mu] m, and / or the total thickness of the polarization sheet is less than or equal to 180 [mu] m. The disclosure also relates to an ophthalmic lens comprising such a sheet, to a method for preparing such an ophthalmic lens, and to the use of a polarizing sheet for imparting polarizing properties to an ophthalmic lens while avoiding or limiting optical distortion.

Description

Technical Field

[0001] This disclosure relates to polymeric ophthalmic lenses having polarization properties.

[0002] This disclosure specifically relates to the use of polarization sheets for imparting polarization properties to ophthalmic lenses while avoiding or limiting optical distortion.

[0003] This disclosure also relates to a method for preparing such ophthalmic lenses.

[0004] This disclosure also relates to a primer-coated sheet. Background Art

[0005] Optical sheets can be included in ophthalmic lenses to provide functions to the ophthalmic lenses. The functions can be light absorption functions (e.g., for absorbing UV light, visible light, and / or IR light), photochromic functions, polarization functions, color enhancement functions.

[0006] Thus, optical sheets are films having optical and thermomechanical properties that make them suitable for inclusion in ophthalmic lenses and include functional films that provide one or more desired functions to the lenses. In some cases, the sheet can be the ophthalmic lens itself.

[0007] Optical sheets can be included in ophthalmic lenses by inserting the optical sheet into a lens mold and injection molding (in the case of a thermoplastic lens substrate) or casting (in the case of a thermosetting lens substrate) the lens substrate against the optical sheet in the lens mold. Thus, the optical sheet can be included on the front surface of the lens substrate, on the back surface of the lens substrate, or embedded in the lens substrate.

[0008] Optical sheets can also be included in ophthalmic lenses by laminating the optical sheet to the lens substrate. In this case, an adhesive can be used to ensure strong adhesion of the optical sheet to the lens substrate.

[0009] Typically, optical sheets are produced by cutting them from a film having the same layer structure as the sheet to the desired size.

[0010] When an optical sheet is included in an ophthalmic lens via injection molding or casting, it is also necessary to shape the sheet before injection molding or casting so as to give the sheet a curvature adapted to the desired curvature of the lens. The shaping is carried out by heating and pressing the sheet in a shaping machine.

[0011] During this process, it is important to protect the sheet or the film used to produce the sheet in order to avoid appearance defects in the final lens. For example, it is necessary to protect the sheet or the film used to produce the sheet from possible contamination or scratches. For this purpose, the optical sheet or the film used to produce the sheet is covered on one or both of its major surfaces with a peelable liner. The liner is removed in the final step of the method if required (e.g., before the injection molding or casting step or before laminating the optical sheet onto the lens substrate).

[0012] Polarizing sheets are typically made of PVA films. Such sheets are widely used, for example, in sunglass lenses. To improve the robustness of the sheet and to facilitate its handling during the casting process of the lens, the polarizing PVA film can be sandwiched between two transparent protective layers of thermoplastic material.

[0013] Typically, the total thickness of a TAC / PVA / TAC sheet is about 200 μm.

[0014] However, the sheet and the polymeric material of the lens exhibit different mechanical properties, such as hardness.

[0015] After demolding from the casting unit, the lens undergoes further processing, such as surface finishing and hard coating, and can be exposed to high temperatures. During these processes, the polymeric material of the lens releases stress and deforms. The deformation of the polymeric material is not at the same level as the deformation of the sheet. In addition, the deformation at the thinnest region of the lens is different from that at the thickest region. This deformation difference can lead to optical distortion of the lens. It has been found that there is a correlation between the optical distortion of the lens and the thickness of the sheet. The higher the thickness of the sheet, the higher the optical distortion.

[0016] The sheets disclosed herein are intended to remedy these drawbacks. SUMMARY OF THE INVENTION

[0017] The following clauses are disclosed herein:

[0018] A. A polarizing sheet comprising the following stacked on top of each other in the following order:

[0019] A1) A thermoplastic film,

[0020] B) A PVA polarizing film,

[0021] A2) A thermoplastic film,

[0022] A1) and A2) are the same or different,

[0023] The thickness of A1) and the thickness of A2) are the same or different, and

[0024] wherein the thickness of A1) and the thickness of A2) are each less than or equal to 80 μm,

[0025] The thickness of B) is less than or equal to 40 μm.

[0026] Abis. A polarizing sheet comprising the following stacked on top of each other in the following order:

[0027] A1) A thermoplastic film,

[0028] B) A PVA polarizing film,

[0029] A2) A thermoplastic film,

[0030] A1) and A2) are the same or different,

[0031] The thickness of A1) and the thickness of A2) are the same or different, and

[0032] wherein the total thickness of the polarizing sheet is less than or equal to 180 μm.

[0033] B. The polarizing sheet according to clause A, wherein the total thickness of the polarizing sheet is less than or equal to 180 μm.

[0034] C. The polarizing sheet according to any one of clauses A - B, wherein the thermoplastic film A1) consists of a single thermoplastic layer.

[0035] D. The polarizing sheet according to any one of clauses A - C, wherein the thermoplastic film A2) consists of a single thermoplastic layer.

[0036] E. The polarizing sheet according to any one of clauses A - D, wherein the PVA polarizing film B) consists of a single thermoplastic layer.

[0037] F. The polarizing sheet according to any one of clauses A - E, wherein the thickness of A1) and the thickness of A2) are the same or different, and are 25 μm to 80 μm, particularly 28 μm to 60 μm, particularly 30 μm to 55 μm, particularly 33 μm to 50 μm, particularly 35 μm to 45 μm, particularly 36 μm to 44 μm, particularly 37 μm to 43 μm, particularly 38 μm to 42 μm, particularly 39 μm to 41 μm.

[0038] G. The polarizing sheet according to any one of clauses A - F, wherein the thickness of B) is 25 μm to 35 μm, particularly 26 μm to 34 μm, particularly 27 μm to 33 μm, particularly 28 μm to 32 μm, particularly 29 μm to 31 μm.

[0039] H. The polarizing sheet according to any one of clauses A - G, wherein the total thickness of the polarizing sheet is 50 μm to 150 μm, particularly 75 μm to 150 μm, particularly 75 μm to 125 μm.

[0040] I. The polarizing sheet according to any one of clauses A - H further includes an intermediate adhesive layer C1) between film B) and film A1) and / or an intermediate adhesive layer C2) between film B) and film A2).

[0041] J. The polarizing sheet according to clause I, wherein the thickness of the intermediate adhesive layer C1) and the thickness of the intermediate adhesive layer C2) are the same or different and are less than or equal to 4 μm.

[0042] K. The polarizing sheet according to clause J, wherein the thickness of C1) and the thickness of C2) are the same or different and are 0.5 μm to 3.5 μm, particularly 1 μm to 3 μm, particularly 1.5 μm to 2.5 μm.

[0043] L. The polarizing sheet according to any one of clauses A - K, wherein the polarizing sheet consists of:

[0044] - The thermoplastic films A1) and A2)

[0045] - The PVA polarizing film B), and

[0046] - Optionally, the adhesive layer C1)

[0047] - Optionally, the adhesive layer C2).

[0048] M. The polarizing sheet according to any one of clauses A - L further includes a dry primer layer D1) applied to film A1) and / or a dry primer layer D2) applied to film A2), and D1) and D2) are the same or different.

[0049] N. The polarizing sheet according to clause M, wherein the thickness of D1) and the thickness of D2) are the same or different and each is less than or equal to 4 μm.

[0050] O. The polarizing sheet according to claim N, wherein the thickness of D1) and the thickness of D2) are the same or different and are 0.5 μm to 3.5 μm, particularly 1 μm to 3 μm, particularly 1.5 μm to 2.5 μm.

[0051] P. The polarizing sheet according to any one of clauses A - O, wherein the thermoplastic films A1) and A2) independently comprise polycarbonate (PC), polymethyl methacrylate (PMMA), polyamide (nylon), polyester (PET), cellulose acetate butyrate (CAB), triacetyl cellulose (TAC), cycloolefin copolymer (COC) or a mixture thereof.

[0052] Q. The polarizing sheet according to any one of clauses A - P has a curved shape.

[0053] AA. A polarized ophthalmic lens, which comprises a polymeric material and a polarizing sheet as described in any one of Clauses A - Q, wherein the polarizing sheet is embedded in the polymeric material or placed on the surface of the polymeric material.

[0054] BB. The polarized ophthalmic lens according to Clause AA, wherein the polymeric material is a thermosetting polymer or a thermoplastic polymer.

[0055] CC. The polarized ophthalmic lens according to Clause BB, wherein the thermoplastic polymer is polycarbonate.

[0056] DD. The polarized ophthalmic lens according to Clause BB, wherein the thermosetting polymer is a urethane or a thiourethane polymer or diethylene glycol bisallyl carbonate.

[0057] EE. The polarized ophthalmic lens according to any one of Clauses AA - DD, wherein the thickness of the polymeric material is not uniform throughout the polarized ophthalmic lens.

[0058] FF. The polarized ophthalmic lens according to any one of Clauses AA - EE, which has a curved shape.

[0059] GG. The polarized ophthalmic lens according to any one of Clauses AA - FF, which further comprises a hard coat applied on at least one surface of the polarized ophthalmic lens.

[0060] HH. The polarized ophthalmic lens according to any one of Clauses AA - GG, wherein the ophthalmic lens is a semi - finished or finished lens.

[0061] AAA. A method for manufacturing a polarized ophthalmic lens according to any one of Clauses AA - FF, the method comprising the following steps:

[0062] - Providing a polarizing sheet as described in any one of Clauses A - P;

[0063] - Providing a liquid polymerizable composition containing monomers or oligomers that form the polymeric material upon polymerization;

[0064] - Cutting and shaping the polarizing sheet to obtain a curved polarizing sheet;

[0065] - Placing the curved polarizing sheet in a casting unit;

[0066] - Introducing the polymerizable liquid composition into the casting unit and depositing the polymerizable liquid composition on one side of the polarizing sheet, or embedding the polarizing sheet in the polymerizable liquid composition;

[0067] - Polymerize the polymerizable liquid composition in the casting unit to obtain a polymeric material; and

[0068] - Demold the polymeric material.

[0069] BBB. The method according to clause AAA, wherein the polymeric material is surface processed.

[0070] CCC. The method according to clause AAA or clause BBB, wherein the polymeric material is hard coated.

[0071] AAAA. Use of the polarizing sheet according to any one of clauses A - Q in the ophthalmic lens according to any one of clauses AA - HH, wherein the polarizing sheet is embedded in the polymeric material or placed on the surface of the polymeric material to impart polarizing properties to the lens while avoiding or limiting optical distortion. Detailed Description

[0072] The sheet of the present disclosure allows for good processability in molding and casting. It is thinner than other TAC / PVA / TAC laminates on the market. It still provides benefits in terms of handling, as the PVA film is protected and enclosed by two TAC film layers on each side.

[0073] The molding process remains simple. No film handling steps are required, allowing for good cost savings in the molding and casting processes.

[0074] The polarizing sheet of the present disclosure can be used to manufacture polarizing ophthalmic lenses with refractive indices of 1.5, 1.6, and 1.67 obtained by a casting process.

[0075] The polarizing sheet of the present disclosure provides better customer perception, improved quality, and reduced manufacturing costs.

[0076] Polarizing sheet

[0077] The polarizing sheet can be attached to one surface of the lens, both surfaces of the lens, or embedded in the lens or any combination thereof.

[0078] The polarizing sheet can be manufactured using a thin polyvinyl alcohol (PVA) polarizing film. To manufacture a lens including the PVA polarizing film, the PVA polarizing film can be subjected to several processing steps, including thermoforming, cutting to a desired diameter, primer application, and placement into a casting unit. The fragile nature of the thin PVA polarizing film combined with these multiple processing steps may increase the likelihood of film damage. Accordingly, the polarizing PVA film of the present disclosure is laminated between thermoplastic films such as triacetyl cellulose (TAC) films in order to provide a robust protective support layer on the surface of the PVA film. A polarizing sheet including the PVA polarizing film laminated between TAC thermoplastic films may be referred to as a TAC-PVA-TAC laminate.

[0079] The thermoplastic film A1) and the thermoplastic film A2) are the same or different.

[0080] The thickness of A1) and the thickness of A2) are the same or different, each being less than or equal to 80 μm. In particular, the thickness of A1) and the thickness of A2) are the same or different and can each be less than or equal to 50 μm.

[0081] In one embodiment, the thickness of the thermoplastic film A1) and the thickness of the thermoplastic film A2) are the same or different and are 25 μm to 80 μm, particularly 28 μm to 60 μm, particularly 30 μm to 55 μm, particularly 33 μm to 50 μm, particularly 35 μm to 45 μm, particularly 36 μm to 44 μm, particularly 37 μm to 43 μm, particularly 38 μm to 42 μm, particularly 39 μm to 41 μm.

[0082] The thickness of the PVA polarizing film B) is less than or equal to 40 μm.

[0083] In one embodiment, the thickness of B) is 25 μm to 35 μm, particularly 26 μm to 34 μm, particularly 27 μm to 33 μm, particularly 28 μm to 32 μm, particularly 29 μm to 31 μm.

[0084] In one embodiment, the sheet of the present disclosure further includes an intermediate adhesive layer C1) placed between the film B) and the layer A1) and / or an intermediate adhesive layer C2) placed between the film B) and the layer A2).

[0085] The intermediate adhesive layer can include polyurethane, glyoxal, or EVOH.

[0086] In one embodiment, the thickness of the intermediate adhesive layer C1) and the thickness of the intermediate adhesive layer C2) are the same or different, each being less than or equal to 4 μm.

[0087] In one embodiment, the thickness of C1) and the thickness of C2) are the same or different and are from 0.5 μm to 3.5 μm, particularly from 1 μm to 3 μm, particularly from 1.5 μm to 2.5 μm.

[0088] In one embodiment, the sheet further comprises a dry primer layer D1) applied on layer A1) and / or a dry primer layer D2) applied on layer A2), and D1) and D2) are the same or different.

[0089] The primer layer can be used to increase the adhesion between the TAC film and the polymeric material of the lens. For example, KR 993596B1 describes a primer coating for improving the adhesion between a TAC film and a cast CR-39 plastic lens in which a TAC laminate is embedded. WO 2018 / 052454 and WO 2019175354A1 describe a primer coating for improving the adhesion between a TAC film and a cast CR-39 plastic lens in which a TAC laminate is embedded. To prepare a CR-39 lens with an embedded TAC laminate, a TAC laminate having a primer coating deposited on the lens contact surface of the laminate is placed in CR-39 monomer such that both surfaces of the TAC polarizing laminate are in contact with the CR-39 monomer. The CR-39 monomer is polymerized to provide a solid polarizing lens, wherein the polarizing function is provided by the TAC polarizing laminate embedded in the lens. WO 2021 / 170702 describes a primer coating for improving the adhesion of a TAC polarizing laminate, which is placed and cast on top of a poly(thio)urethane lens (such as a high refractive index UHI Mitsui lens) (TAC-on-TOP). In a TAC-on-TOP lens, there is only one adhesion interface between the TAC film or TAC laminate and the UHI lens. Since TAC itself may not have sufficient adhesion to the UHI lens, a primer coating may be required to adhere the TAC film or TAC laminate to the UHI lens.

[0090] The primer composition can be applied to any one surface of the sheet or to both surfaces of the sheet. Preferably, the primer composition is applied to one major surface of the sheet.

[0091] The primer composition can be applied to the sheet by any method, including but not limited to spraying or roll coating. The primer composition can be air dried or dried in an air oven and can be cured by UV irradiation or exposure to heat. Preferably, the primer composition is dried in an air oven and then cured by UV irradiation before the next step.

[0092] The degree of curing of the primer composition is not limited. For example, when the primer composition does not move on the surface of the sheet in the casting unit for casting lenses described below, the primer composition can be considered to be sufficiently cured. In addition, when the primer composition does not appear wet, the primer composition can be considered to be sufficiently cured.

[0093] A protective film layer can be applied on the dried primer-coated sheet to maintain the integrity of the surface quality. In a roll-to-roll process, the rolled-up roll with the protective film layer attached can be safely stored.

[0094] After applying the primer coating composition, the sheet can be formed into the desired shape before applying a lining to protect the primer surface. For example, the sheet can be bent to fit into the casting unit for casting lenses, or cut into a suitable shape or size. Preferably, after the primer coating composition is sufficiently cured by UV or heat, the sheet is formed into the desired shape.

[0095] The thickness of D1) and the thickness of D2) are the same or different.

[0096] The thickness of D1) and the thickness of D2) can each be less than or equal to 4 μm.

[0097] In one embodiment, the thickness of D1) and the thickness of D2) are the same or different and are 0.5 μm to 3.5 μm, particularly 1 μm to 3 μm, particularly 1.5 μm to 2.5 μm.

[0098] The thermoplastic film layers A1) and A2) are the same or different and can independently comprise polycarbonate (PC), polymethyl methacrylate (PMMA), polyamide (nylon), polyester (PET), cellulose acetate butyrate (CAB), triacetyl cellulose (TAC), cycloolefin copolymer (COC) or a mixture thereof.

[0099] In one embodiment, the sheet disclosed herein has a curved shape.

[0100] Ophthalmic lens

[0101] The polarizing ophthalmic lens disclosed herein comprises a polymeric material and a polarizing sheet as previously described, with the polarizing sheet being embedded in the polymeric material or placed on the surface of the polymeric material.

[0102] In one embodiment, the polymeric material is a thermosetting polymer [CR39, MR7] or a thermoplastic polymer.

[0103] In one embodiment, the polarizing ophthalmic lens has a curved shape.

[0104] In one embodiment, the thickness of the polymeric material across the polarized ophthalmic lens is not uniform. In fact, typically, the thickness at the center of the lens is less than the thickness at the edge of the lens.

[0105] In one embodiment, the thermoplastic polymer is polycarbonate.

[0106] In one embodiment, the thermosetting polymer is a urethane or thiourethane polymer [MR-7] or diethylene glycol bis allyl carbonate [CR39].

[0107] For example, a poly(thio)urethane lens having a refractive index of about 1.67 such as The lens can be produced by polymerizing (diisocyanate) and (trithiol). The poly(thio)urethane lens can be a high refractive index lens (1.60) or an ultra-high refractive index lens (1.67). Poly(thio)urethane lenses typically have an ultra-high refractive index and can be preferably used for producing high-quality glasses.

[0108] In one embodiment, the polarized ophthalmic lens as previously described further comprises a hard coat applied on at least one surface of the polarized ophthalmic lens.

[0109] In one embodiment, the ophthalmic lens is a semi-finished or finished lens.

[0110] Method for manufacturing a polarizing ophthalmic lens

[0111] The lens of the present disclosure can be manufactured by a method comprising the following steps:

[0112] - Providing a polarized sheet comprising the following stacked on top of each other in the following order:

[0113] A1) A thermoplastic film layer,

[0114] B) A PVA polarizing film,

[0115] A2) A thermoplastic film layer,

[0116] A1) and A2) are the same or different,

[0117] The thickness of A1) and the thickness of A2) are the same or different, and

[0118] wherein the thickness of A1) and the thickness of A2) are each less than or equal to 80 μm, for example less than 50 μm,

[0119] The thickness of B) is less than or equal to 40 μm;

[0120] - Providing a liquid polymerizable composition containing monomers or oligomers that form the polymeric material upon polymerization;

[0121] - Cut the polarizing sheet and shape it to obtain a bent polarizing sheet;

[0122] - Place the bent polarizing sheet in a casting unit;

[0123] - Introduce the polymerizable liquid composition into the casting unit and deposit the polymerizable liquid composition on one side of the polarizing sheet, or embed the polarizing sheet in the polymerizable liquid composition;

[0124] - Polymerize the polymerizable liquid composition in the casting unit to obtain a polymeric material; and

[0125] - Demold the polymeric material.

[0126] In one embodiment, the monomer comprises at least one urethane monomer, preferably at least one thiourethane lens casting monomer, such as

[0127] In one embodiment, the monomer comprises CR39, which is a blend of an allyl monomer and an oligomer derived from diethylene glycol bis(allyl carbonate).

[0128]

[0129] Diethylene glycol bis(allyl carbonate)

[0130] The sheet and the polymerizable liquid composition can be placed in the casting unit such that a lens is formed on one surface of the sheet. The sheet and the polymerizable liquid composition can also be placed in the casting unit such that the sheet is embedded in the lens. Preferably, the sheet and the polymerizable liquid composition are placed in the casting unit such that a lens is formed on the side of the sheet on which a dry primer layer composition has been applied.

[0131] Any casting unit suitable for casting lenses can be used. Additionally, the casting conditions are not limited as long as the lens is properly formed from the lens casting monomer in the casting unit.

[0132] After the lens is formed, the lens is demolded, i.e., removed from the casting unit, and optionally subjected to suitable treatments such as prescription surface finishing treatment, hard coating treatment, and anti-reflection coating treatment.

[0133] Use

[0134] Another aspect of the present disclosure is the use of the polarizing sheet of the present disclosure in an ophthalmic lens comprising a polymeric material, wherein the polarizing sheet is embedded in the polymeric material or placed on the surface of the polymeric material for imparting polarizing properties to the lens while avoiding or limiting optical distortion.

[0135] General definition

[0136] As defined herein, an ophthalmic lens is a lens designed for use in a monocle or spectacles (including sunglasses, goggles, and safety glasses). As defined herein, a contact lens is not an ophthalmic lens. Ophthalmic lenses are typically used to protect the eyes and / or correct vision. Ophthalmic lenses can be non-corrective ophthalmic lenses (also known as plano or afocal lenses) or corrective ophthalmic lenses. Corrective lenses can be single-focus lenses, bifocal lenses, trifocal lenses, or progressive lenses. As defined herein, an ophthalmic lens can be a finished lens of a semi-finished lens. The semi-finished lens undergoes various processing steps such as surface finishing, coloring, coating, and edging before finally being incorporated into spectacles or a monocle. The finished lens is ready to be incorporated into spectacles or a monocle.

[0137] As defined herein, a film is a stack of one or more layers.

[0138] A layer corresponds to the thickness of a given material between two interfaces. As defined herein, a stack of two or more layers is not a layer. The interface between two consecutive layers can typically be observed with a microscope.

[0139] Layers can be assembled by coextrusion or by pressing the layers against each other. In some cases, inserting an adhesive layer between two layers before pressing the two layers together facilitates the assembly of the two layers. In some cases, the electrostatic force between the layers is sufficient to assemble them with only minimal pressure. As defined herein, an adhesive layer is considered a layer.

[0140] In the present disclosure, a polymeric material can comprise only one polymer or a blend of polymers. It should be understood that in such cases, in addition to the only one polymer or polymer blend, a layer can contain additives.

[0141] As defined herein, a film or layer "placed on a surface" is defined as a film or layer that (a) is placed above the surface, (b) does not need to be in direct contact with the surface, i.e., one or more intermediate layers can be provided between the surface and the film or layer in question, and (c) does not need to completely cover the surface. However, preferably, the film or layer completely covers the surface.

[0142] Example

[0143] The tested sheets are as follows (showing the thickness; when "layer" is plural, there are two identical such layers, and the thickness shown is the thickness of one layer):

[0144]

[0145] For each sheet, a lens sample was obtained as follows:

[0146] - Place the bent sheet in the casting unit;

[0147] - Introduce CR39 into the casting unit and deposit it on the concave side of the bent sheet;

[0148] - Polymerize the CR39 to obtain a semi-finished lens sample;

[0149] - Machine the surface of the semi-finished lens sample to a central thickness of 2.1 mm and a sphericity of -6.0 diopters to obtain a finished lens sample.

[0150] For each lens, a 2D map of the surface of the lens is measured using a dual-lens mapper (from Automation & Robotics SA). Figure 1 The distribution maps presented are obtained from these 2D maps. They represent the power error measured on the convex surface of the lens (i.e., the deviation compared to the target power of the lens, which corresponds to unwanted distortion).

[0151] It can be seen that lens samples 1 and 2 have satisfactory power errors, while lens samples 3 and 4 have much higher errors. At the same time, compared to lens sample 1, lens sample 2 is easier to obtain (sheet 2 is easier to process because it is protected by the TAC layer, and sheet 1 requires additional adjustment steps and higher requirements in terms of controlling humidity and temperature conditions).

Claims

1. A polarizing sheet, which comprises the following stacked on top of each other in the following order: A1) A thermoplastic film, B) A PVA polarizing film, A2) A thermoplastic film, A1) and A2) are the same or different, The thickness of A1) and the thickness of A2) are the same or different, and wherein the thickness of A1) and the thickness of A2) are each less than or equal to 80 μm, The thickness of B) is less than or equal to 40 μm.

2. A polarizing sheet, which comprises the following stacked on top of each other in the following order: A1) A thermoplastic film, B) A PVA polarizing film, A2) A thermoplastic film, A1) and A2) are the same or different, The thickness of A1) and the thickness of A2) are the same or different, and wherein the total thickness of the polarizing sheet is less than or equal to 180 μm.

3. The polarizing sheet according to claim 1, wherein, The total thickness of the polarizing sheet is less than or equal to 180 μm.

4. The polarizing sheet according to any one of claims 1 - 3, wherein, The thickness of A1) and the thickness of A2) are the same or different, and are 25 μm to 80 μm, particularly 28 μm to 60 μm, particularly 30 μm to 55 μm, particularly 33 μm to 50 μm, particularly 35 μm to 45 μm, particularly 36 μm to 44 μm, particularly 37 μm to 43 μm, particularly 38 μm to 42 μm, particularly 39 μm to 41 μm.

5. The polarizing sheet according to any one of claims 1 - 4, wherein, The thickness of B) is 25 μm to 35 μm, particularly 26 μm to 34 μm, particularly 27 μm to 33 μm, particularly 28 μm to 32 μm, particularly 29 μm to 31 μm.

6. The polarizing sheet according to any one of claims 1 - 5, wherein, The total thickness of the polarizing sheet is 50 μm to 150 μm, particularly 75 μm to 150 μm, particularly 75 μm to 125 μm.

7. The polarizing sheet according to any one of claims 1 - 6, which further comprises an intermediate adhesive layer C1) between film B) and film A1) and / or an intermediate adhesive layer C2) between film B) and film A2).

8. The polarizing sheet according to any one of claims 1 - 7, wherein, The polarizing sheet consists of the following: - The thermoplastic films A1) and A2) - The PVA polarizing film B), and - Optionally, the adhesive layer C1) - Optionally, the adhesive layer C2).

9. The polarizing sheet according to any one of claims 1 - 8, which further comprises a dry primer layer D1) applied to film A1) and / or a dry primer layer D2) applied to film A2), D1) and D2) being the same or different.

10. The polarizing sheet according to any one of claims 1 - 9, wherein, The thermoplastic films A1) and A2) independently comprise polycarbonate (PC), polymethyl methacrylate (PMMA), polyamide (nylon), polyester (PET), cellulose acetate butyrate (CAB), triacetyl cellulose (TAC), cycloolefin copolymer (COC) or a mixture thereof.

11. The polarizing sheet according to any one of claims 1 - 10, which has a curved shape.

12. A polarizing ophthalmic lens, which comprises a polymeric material and the polarizing sheet according to any one of claims 1 - 11, with the polarizing sheet being embedded in the polymeric material or placed on the surface of the polymeric material.

13. The polarizing ophthalmic lens according to claim 12, wherein, the ophthalmic lens is a semi - finished or finished lens.

14. A method for manufacturing the polarizing ophthalmic lens according to claim 12 or claim 13, the method comprising the following steps: - providing the polarizing sheet according to any one of clauses 1 - 10; - providing a liquid polymerizable composition containing monomers or oligomers that form the polymeric material upon polymerization; - cutting and shaping the polarizing sheet so as to obtain a curved polarizing sheet; - placing the curved polarizing sheet in a casting unit; - introducing the polymerizable liquid composition into the casting unit and depositing the polymerizable liquid composition on one side of the polarizing sheet, or causing the polarizing sheet to be embedded in the polymerizable liquid composition; - polymerizing the polymerizable liquid composition in the casting unit to obtain a polymeric material; and - demolding the polymeric material.

15. Use of the polarizing sheet according to any one of claims 1 - 11 in the ophthalmic lens according to claim 12 or 13, with the polarizing sheet being embedded in the polymeric material or placed on the surface of the polymeric material, for imparting polarizing properties to the lens while avoiding or limiting optical distortion.

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