Polarized lens with color enhancement characteristics

Abstract

The invention relates to a color-enhanced polarizing multilayer film (1) comprising:-a polarizing layer (12) having a front side and a back side; a first protective layer (11); a second protective layer (13); and-one or more isotropic dyes contained in at least one of the first protective layer or the second protective layer; wherein the first protective layer is disposed on the front side of the polarizing layer and the second protective layer is disposed on the back side of the polarizing layer, and wherein the one or more isotropic dyes comprise at least 90 wt.%, preferably at least 95 wt.%, also preferably at least 99 wt.% of the total content of the dyes contained in the first and second protective layers.

Description

Technical Field

[0001] The present invention relates to the technical field of polarized lenses, and more particularly to such polarized lenses having color enhancement properties. Such polarized lenses are suitable for use in sunglasses. Background Art

[0002] Polarized lenses with color enhancement properties are known in the art. Various methods can be used to manufacture such lenses. For example, US 9575335B1 of Oakley Inc. (USA) provides color-enhanced lenses with an absorbance peak at about 470nm and another absorbance peak at about 570nm. These color-enhanced lenses contain "chromaticity enhancement dyes", which are defined as dyes that produce a discernible and / or significant chromaticity enhancement effect in at least some types of scenes viewed by a viewer when the amount is sufficient. Such dyes are used in conjunction with light polarizing films to filter out polarized light reflected from a surface such as water. The resulting lenses are said to improve color perception, clarity, and vividness.

[0003] US 6145984 A also describes a color enhanced polarized lens, in which the polarized lens is dyed to have trichromatic properties, i.e., to favor the transmission of three different colors (about 440nm, 500nm and 630nm). The lens is made of a polarizing film sandwiched between a front photochromic lens and a rear lens with trichromatic properties. Not much is said about the dyes used. Such lenses are said to provide improvements in color perception and clarity, and reduce glare.

[0004] Other documents such as US2017 / 0139234 use a combination of polarizing filters and retarder stacks to achieve color enhancement through spectral transmission tuning. Dyes can be used but only to provide the desired color balance and overall hue of the lens. In particular, such lenses include a retarder stack sandwiched between two polarizers. The alignment of the polarizer and retarder stack is critical to achieving the desired color effect.

[0005] US2298058 A and WO 2016 / 125694 A1 use two color polarization filters that are fixed at 90° to each other (the former) or one is rotatable relative to the other (the latter). In these lenses, dichroic dyes are used. Here, dichroism is described as the property of differential absorption of the components of the incident light beam according to the vibration direction of these components. In order to achieve the dichroic property, the dye must be oriented. Again, the necessity of the orientation of the dye on two separate filters makes the manufacture of the lens more difficult, because a small misalignment will not provide the desired color effect.

[0006] Further, while in some cases the result of misalignment does not affect the color enhancement properties, it may nevertheless reduce the amount of transmitted light. However, in some applications, and particularly for sunglasses, the reduction in the amount of transmitted light may prevent the lenses from being suitable for certain activities, such as driving. In fact, laws define a minimum amount of transmitted light for sunglasses to be labeled suitable for driving. Summary of the invention

[0007] It is an object of the present invention to overcome at least one of the disadvantages of the prior art.

[0008] The object is achieved by providing a color-enhanced polarizing multilayer film, the color-enhanced polarizing multilayer film comprising:

[0009] - having a front and a back polarizing layer;

[0010] - first protective layer;

[0011] - a second protective layer; and

[0012] - one or more isotropic dyes contained in at least one of the first protective layer or the second protective layer;

[0013] wherein the first protective layer is disposed on the front side of the polarizing layer, and the second protective layer is disposed on the back side of the polarizing layer, and

[0014] The one or more isotropic dyes account for at least 90 wt.%, preferably at least 95 wt.%, and further preferably at least 99 wt.% of the total content of dyes contained in the first protective layer and the second protective layer.

[0015] The present invention achieves effective color enhancement by changing two features common in current color-enhancing polarized lenses: it uses only one polarizing layer, and it uses isotropic dyes rather than dichroic dyes in one or more of the color-enhancing layers.

[0016] The use of isotropic dyes in a color enhancement layer applied to a polarizing film to achieve a color enhanced polarized lens is unknown to the authors of the present invention.The different layers of such polarized lenses are bonded together by lamination.

[0017] The use of a dichroic dye in a non-oriented manner in the color enhancement layer can in principle avoid the obligation to orient the dye-containing layer parallel to the polarizing layer in order to obtain the desired color enhancement effect. However, even when the dichroic dye of the color enhancement layer is not intentionally oriented, the process used to form the layer (e.g., an extrusion process) results in a certain percentage of the dichroic dye being aligned in one direction (e.g., the extrusion direction). Therefore, when laminating the color enhancement layer and the polarizing layer together, the angle between the different layers must be precisely controlled in order to avoid undesirable effects, such as a significantly reduced amount of transmitted light.

[0018] The inventors have found that using isotropic dyes eliminates the risk of dye orientation during layer formation (eg by extrusion) and still provides a colour enhancing effect to the lens.

[0019] Another aspect of the present invention relates to an ophthalmic lens comprising the multilayer film of the present invention and a substrate injection molded onto the multilayer film.

[0020] Another aspect of the present invention relates to a method for producing the multilayer film of the present invention, the method comprising the following steps:

[0021] - providing a polarizing layer;

[0022] - extruding a first mixture comprising a first base material to obtain a first protective layer;

[0023] - extruding a second mixture comprising a second base material to obtain a second protective layer; and

[0024] - laminating the first protective layer, the polarizing layer and the second protective layer into a multilayer film;

[0025] wherein the one or more isotropic dyes are contained in at least one of the first mixture or the second mixture; and

[0026] The one or more isotropic dyes account for at least 90 wt.%, preferably at least 95 wt.%, and even more preferably at least 99 wt.% of the total content of dyes contained in the first mixture and the second mixture.

[0027] Another aspect of the invention relates to a method for producing an ophthalmic lens of the invention from a multilayer film of the invention, the method comprising injection molding a substrate onto the multilayer film. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] exist Figure 1 , the transmission spectra of an arbitrary example of a gray polarizing film and a colored polarizing film and the polarization efficiency (PE) of the colored polarizing film as a function of wavelength are shown.

[0029] exist Figure 2 , the transmission spectra of a combination of an arbitrary example of a gray polarizing film and a colored polarizing film at various orientation angles between the two films are shown.

[0030] Figure 3 Shown are the transmission spectra of the CE layer and its polarization efficiency (PE) as a function of wavelength.

[0031] Figure 4 The transmission spectrum of the prototype lens is shown in , along with the transmission spectrum of a standard Type 3 green-grey polarized lens (no colour enhancement).

[0032] Figure 5a-5c The color enhancement (chromaticity difference ΔC) of a color enhanced polarized lens relative to a standard tinted polarized lens at 20,000 lux is shown in FIG. Figure 5a-5c Also shown above is the change in hue (Δh) of the color enhanced polarized lens compared to the hue observed in the absence of any kind of filter.

[0033] Figure 6 is a schematic cross-sectional view of a multilayer film of the present invention.

[0034] Figure 7 is a schematic cross-sectional view of another embodiment of a multilayer film of the present invention having a convex front side and a concave back side. DETAILED DESCRIPTION

[0035] The object of the present invention is a color-enhanced polarizing multilayer film 1 comprising:

[0036] - a polarizing layer 12 having a front side and a back side;

[0037] - a first protective layer 11;

[0038] - a second protective layer 13; and

[0039] - one or more isotropic dyes contained in at least one of the first protective layer 11 or the second protective layer 13;

[0040] The first protective layer 11 is placed on the front side of the polarizing layer 12, and the second protective layer 13 is placed on the back side of the polarizing layer 12, and

[0041] The one or more isotropic dyes account for at least 90 wt.%, preferably at least 95 wt.%, and further preferably at least 99 wt.% of the total content of dyes contained in the first protective layer 11 and the second protective layer 13.

[0042] The multilayer film 1 of the present invention can be included in an ophthalmic lens to impart polarization and color enhancement properties to the lens. For example, the inclusion of the multilayer film 1 in an ophthalmic lens can be obtained by injection molding a lens substrate on one side of the film. In some embodiments, the multilayer film 1 of the present invention can be used directly as a color-enhanced polarized ophthalmic lens, for example after forming it into a spherical shape and edging it to make it suitable for mounting on a spectacle frame.

[0043] As defined herein, an ophthalmic lens may be a finished lens or a semi-finished lens designed to fit into a spectacle frame (in some cases after various processing steps such as surface treatment and edging) in order to protect the eye and / or correct or enhance or change vision. The ophthalmic lens may be a non-corrective ophthalmic lens (also known as a plano lens or afocal lens) or a corrective ophthalmic lens. Corrective lenses may be single-focal lenses, bifocal lenses, trifocal lenses, or progressive lenses.

[0044] As defined herein, the front side is the side that is further away from the wearer's eyes when the film is included in the ophthalmic lens of a pair of glasses. The back side is the side that is closer to the wearer's eyes when the film is included in the ophthalmic lens of a pair of glasses.

[0045] The first protective layer 11 and the second protective layer 13 provide protection for the polarizing layer 12, for example, protection from high temperatures used during injection molding or protection during storage and use.

[0046] As defined herein, an isotropic dye is a dye having a dichroic ratio (A || / A ⊥ ) is less than 3, wherein A || and A ⊥ are the absorbance values ​​of linearly polarized light having polarization axes parallel to and perpendicular to the film stretch axis, respectively. To measure the absorbance values, the dye is dispersed in a polyvinyl alcohol polymer film and oriented by stretching the film (e.g., at a stretch ratio between 1:3 and 1:10). As defined herein, anisotropy is a dye having a dichroic ratio greater than 10 as measured by the above method.

[0047] The multilayer film 1 may include one or more layers in addition to the polarizing layer 12 and the first and second protective layers 11 and 13 .

[0048] As defined herein, a layer "on" a surface is defined as a layer that (a) is located above the surface, (b) need not be in contact with the surface, i.e., one or more intermediate layers may be disposed between the surface and the layer in question, and (c) need not completely cover the surface. However, preferably, a layer "on" a surface completely covers the surface.

[0049] The low amount of anisotropic dye contained in the first and second protective layers 13 makes it simpler to extrude these layers and laminate the films without causing undesirable effects such as unexpected color changes or significantly reduced amounts of transmitted light.

[0050] In one embodiment, the multilayer film 1 of the present invention comprises only one polarizing layer 12 .

[0051] As defined herein, polarizing layer 12 is a stretched polymer layer that includes additives that enhance the polarizing function of the stretched polymer layer. Such additives may include dichroic dyes.

[0052] Preferably, in the multilayer film 1 of the present invention, the one or more isotropic dyes account for at least 90 wt.%, more preferably at least 95 wt.%, even more preferably at least 99 wt.% of the total content of dyes contained in the layers other than the polarizing layer 12.

[0053] Preferably, in the multilayer film 1 of the present invention, substantially all dyes contained in the first protective layer 11 and the second protective layer 13 are contained in the first protective layer 11 , or substantially all dyes contained in the first protective layer 11 and the second protective layer 13 are contained in the second protective layer 13 .

[0054] Preferably, in the multilayer film 1 of the present invention, substantially all dyes contained in layers other than the polarizing layer 12 are contained in the first protective layer 11 and the second protective layer 13, more preferably, substantially all dyes contained in layers other than the polarizing layer 12 are contained in the first protective layer 11, or substantially all dyes contained in layers other than the polarizing layer 12 are contained in the second protective layer 13.

[0055] Preferably, in the multi-layer film 1 of the present invention, the dye contained in the first protective layer 11 and the second protective layer 13 does not substantially contain an anisotropic dye.

[0056] Preferably, in the multilayer film 1 of the present invention, the dye contained in the layers other than the polarizing layer 12 does not substantially contain an anisotropic dye.

[0057] Preferably, in the multilayer film 1 of the present invention, the one or more isotropic dyes contained in at least one of the first protective layer 11 or the second protective layer 13 include at least one of a broadband isotropic dye and a narrowband isotropic dye.

[0058] Preferably, in the multilayer film 1 of the present invention, the one or more isotropic dyes contained in at least one of the first protective layer 11 or the second protective layer 13 comprise at least one narrow-band isotropic dye and optionally at least one broadband isotropic dye.

[0059] Preferably, in the multilayer film 1 of the present invention, the one or more isotropic dyes contained in at least one of the first protective layer 11 or the second protective layer 13 include 1 to 10 narrow-band dyes and 1 to 10 broadband dyes, more preferably 1 to 5 narrow-band dyes and 1 to 5 broadband dyes.

[0060] As defined herein, a broadband dye is a dye whose main absorption peak has a full width at half maximum (FWHM) of at least 90 nm.

[0061] Throughout this invention document, the standard definition of FWHM is used, except for absorption peaks near the edge of the visible light wavelength range (near 380nm or near 780nm), for which FHWM is defined as twice the half-width at half maximum measured on the peak side in the visible light range.

[0062] As defined herein, a narrow-band dye is a dye whose main absorption peak has a full width at half maximum of less than 80 nm. A narrow-band absorption peak is an absorption peak with a full width at half maximum of less than 80 nm.

[0063] As defined herein, the main absorption peak of a dye is an absorption peak having a maximum in the visible region (between 380 nm and 780 nm), which is the highest of all absorption peaks of the dye having a maximum in the visible region. According to this definition, in particular, the derivative of the curve: absorbance = f (λ) is 0 at the maximum of the absorption peak.

[0064] Preferably, in the multilayer film 1 of the present invention, the at least one broadband isotropic dye is selected from the group consisting of: Solvent Yellow 93, Solvent Orange 60, Solvent Red 52, Solvent Red 111, Solvent Red 169, Solvent Violet 13, Solvent Violet 14, Solvent Violet 31, Solvent Violet 36, Solvent Violet 38, Solvent Violet 50, Solvent Blue 101, Solvent Blue 104, Solvent Blue 138 and Solvent Green 3.

[0065] One skilled in the art can select broadband dyes in order to balance the color of the multilayer film 1 to obtain a desired color.

[0066] Preferably, in the multilayer film 1 of the present invention, when the at least one narrow-band isotropic dye is incorporated into a layer of the multilayer film 1 comprising the same, the at least one narrow-band isotropic dye exhibits a maximum value of a narrow-band absorption peak at 400 to 700 nm, more preferably 450 to 640 nm, and even more preferably 470 to 615 nm.

[0067] In the present invention, the specific selection of narrow-band dyes and the wavelength of their absorption peaks is causing the color enhancement effect.

[0068] Color enhancement can be quantified by measuring chromaticity (C) and hue (h) using a model developed by the International Commission on Illumination called CIECAM02, see International Commission on Illumination. A Color Appearance Model For Color Management Systems: CIECAM02. CIE 159:2004. CIE Central Bureau, 2004. In particular, the color enhancement of a particular filter is evaluated by comparing the chromaticity (C) values ​​with and without the filter or with two different filters that may be desired to be compared for 18 specific colors. The C value for each color is calculated by the equation set forth in the CIECAM02 model after obtaining the product of the spectral reflectance of the color and the spectral transmittance of the filter. The selection of these 18 colors is intended to simulate the colors of natural objects (e.g., human skin, foliage, and flowers); as well as primary colors such as red, green, blue, yellow, magenta, and cyan. The percent change in C (% ΔC) for each of the 18 colors can be given as:

[0069]

[0070] Color enhancement filters may also distort the natural hue of the color, making the object color look different. Hue (h) is a measure expressed in degrees that describes the color of the object in numbers. The hue of each color is also the output result calculated by the equation set forth in the CIECAM02 model after obtaining the spectral reflectance of the color. The hue of each color with a filter can also be calculated by multiplying the spectral reflectance of the color with the spectral transmittance of the filter. The hue of a specific filter is evaluated by comparing the hue (h) values ​​with and without the filter for 18 specific colors. The hue shift (Δh) of each color is calculated as the hue with the filter minus the hue without the filter. The hue shift can be negative or positive. For this reason, the absolute value of the hue difference is used to understand how much color shift there is.

[0071] Δh=|h 滤光器 -h 无滤光器 |

[0072] The maximum hue difference of those 18 colors can then be used to understand how much total shift there may be.

[0073] The calculation can be adjusted to simulate outdoor brightness levels. For example, for a sunny environment, an illuminance value of 20,000 lux can be used, while for a shaded environment, an illuminance value of 100 lux can be used. These can be referred to as "C20K" and "C100", respectively. The 18 different %ΔC values ​​for each color can then be averaged to calculate a value known as %ΔC 平均 The average change of .

[0074] The Macbeth ColorChecker codes for the 18 colors are: (E2,116); (D1,120); (B3,139); (F1,178); (F3,219); (C1,248); (A3,263); (B2,265); (E1,282); (D2,316); (E3,349); (C2,16); (C3,24); (B1,41); (A1,42); (A2,55); (F2,75); and (D3,92).

[0075] Preferably, the multilayer film 1 of the present invention comprises a first narrow-band isotropic dye, which, when incorporated into a layer of the multilayer film 1 comprising the first narrow-band isotropic dye, exhibits a main absorption peak maximum at 485 to 515 nm, more preferably 490 to 510 nm; and a second narrow-band isotropic dye, which, when incorporated into a layer of the multilayer film 1 comprising the first narrow-band isotropic dye, exhibits a main absorption peak maximum at 570 to 600 nm, even more preferably 575 to 595 nm.

[0076] As demonstrated in the Examples section of this invention document, this specific selection of narrow-band dyes imparts a particularly desirable color enhancement effect to the inventive multilayer film 1, wherein there is only minimal color distortion in view of the color enhancement achieved.

[0077] Preferably, the second narrow-band isotropic dye is present in the multilayer film 1 in a concentration comprised between 1.2 and 2 times the concentration of the first narrow-band isotropic dye.

[0078] Preferably, in the multilayer film 1 of the present invention, the at least one narrow-band isotropic dye exhibits a FWHM of 15 to 40 nm, more preferably 16 to 38 nm, even more preferably 18 to 36 nm.

[0079] In this case, it is to be understood that, in case the multilayer film 1 comprises more than one narrow-band isotropic dye, each narrow-band isotropic dye exhibits a FWHM as defined above.

[0080] Preferably, in the multilayer film 1 of the present invention, the at least one narrow-band isotropic dye is selected from the group consisting of: Epolight 5841, Epolight 5819 and Epolight 6698.

[0081] Preferably, the first narrow-band isotropic dye is Epolight 5841 and the second narrow-band isotropic dye is Epolight 5819.

[0082] Preferably, in the multilayer film 1 of the present invention, the first protective layer 11 and the second protective layer 13 independently contain a thermoplastic polymer selected from polycarbonates such as polycarbonate of bisphenol A, polyesters such as polyethylene terephthalate, polyacrylates such as poly(ethyl methacrylate) or poly(methyl methacrylate) and mixtures thereof as a base material, more preferably, the first protective layer 11 and the second protective layer 13 contain the same thermoplastic polymer as a base material, even more preferably, the first protective layer 11 and the second protective layer 13 contain polycarbonates such as polycarbonate of bisphenol A as a base material.

[0083] According to the invention, the base material of a layer constitutes at least 95 wt.% of said layer.

[0084] Preferably, in the multi-layer film 1 of the present invention, the polarizing layer 12 contains polyvinyl alcohol as a base material.

[0085] Preferably, the multilayer film 1 of the invention comprises a front side 14 and a back side 15 , wherein the front side 14 is convex and the back side 15 is concave.

[0086] Preferably, in this case, all layers comprised in the multilayer film 1 according to the invention have a convex front side and a concave back side.

[0087] The front side 14 and the back side 15 of the multilayer film 1 and all layers comprised therein are defined mutatis mutandis as the front side and the back side of the polarizing layer 12 defined above.

[0088] Preferably, in the multilayer film 1 of the present invention, the first protective layer 11 is a uniaxially stretched layer, for example, having a stretching ratio of 1:2 to 1:10.

[0089] In some cases, stretching the polymer forming the first protective layer 11 improves the properties of the multilayer film 1 of the present invention. This is the case, for example, when the polymer used for the first protective layer 11 exhibits birefringence. In this case, when the multilayer film 1 is included in a lens, the light sequentially passes through the birefringent layer and through the polarizing layer before reaching the wearer's eye. As a result, the wearer will experience unwanted image distortion. In these cases, the undesirable birefringence effect of the first protective layer 11 can be eliminated by orienting the polymer in the first protective layer 11 (e.g., by stretching).

[0090] It has been noted that when a layer is stretched, there is a risk that the dye contained within the layer becomes oriented. The inventors have found that when the dye is anisotropic, this can lead to unwanted changes in the absorption spectrum of the layer. Using an isotropic dye helps to avoid this.

[0091] According to the present invention, the stretch ratio of a layer is defined as the ratio between the initial length and the final length of the film before and after stretching.

[0092] Another object of the invention is an ophthalmic lens comprising the multilayer film 1 according to the invention and a substrate injection-moulded onto the multilayer film 1 .

[0093] Preferably, in the ophthalmic lens of the present invention, the substrate is injection molded directly onto the second protective layer 13. Alternatively, in the ophthalmic lens of the present invention, the substrate is injection molded directly onto the first protective layer 11.

[0094] Preferably, the ophthalmic lens of the present invention exhibits a |Δh lower than 15°, more preferably lower than 10°. 最大 |value.

[0095] Preferably, the ophthalmic lenses of the present invention exhibit a % ΔC of at least 7%, more preferably at least 10%, as measured according to the above-mentioned model developed by the International Commission on Illumination called CIECAM02. 平 all.

[0096] Another object of the present invention is a method for producing the multilayer film 1 according to the invention, comprising the following steps:

[0097] - providing a polarizing layer;

[0098] - extruding a first mixture comprising a first base material to obtain a first protective layer 11;

[0099] - extruding a second mixture comprising a second base material to obtain a second protective layer 13; and

[0100] - laminating the first protective layer 11, the polarizing layer 12 and the second protective layer 13 into a multilayer film 1;

[0101] wherein the one or more isotropic dyes are contained in at least one of the first mixture or the second mixture; and

[0102] The one or more isotropic dyes account for at least 90 wt.%, preferably at least 95 wt.%, and even more preferably at least 99 wt.% of the total content of dyes contained in the first mixture and the second mixture.

[0103] Preferably, the method for producing the multilayer film 1 of the present invention further comprises stretching the first protective layer 11 , wherein the stretching is performed before lamination; for example, the stretching is performed at a stretching ratio between 1:2 and 1:10.

[0104] Preferably, the method for producing the multilayer film 1 according to the invention further comprises shaping the multilayer film 1 , in particular by using a cutting press.

[0105] Preferably, the method for producing the inventive multilayer film 1 further comprises thermoforming the multilayer film 1 to provide a multilayer film 1 having a convex front side 14 and a concave back side 15, wherein thermoforming is performed after lamination and, where applicable, after forming.

[0106] Another object of the invention is a method for producing an ophthalmic lens according to the invention from a multilayer film 1 according to the invention, comprising injection molding a substrate onto the multilayer film 1 .

[0107] Preferably, in the method for producing the ophthalmic lens of the invention, the substrate is injection molded onto the back side 15 of the multilayer film 1 .

[0108] Examples

[0109] Model experiment

[0110] This model experiment was designed to demonstrate the transmission loss that may result from misalignment of a polarizing layer and misalignment of another layer containing an oriented anisotropic dye.

[0111] In this model experiment, any example of a grey polarizing layer was combined with a colored polarizing layer comprising an oriented dichroic dye.

[0112] exist Figure 1 , the transmission spectra of an arbitrary example of a gray polarizing film and a colored polarizing film and the polarization efficiency (PE) of the colored polarizing film as a function of wavelength are shown.

[0113] exist Figure 2 , the transmission spectra of any example of a gray polarizing film and a combination of a colored polarizing film at various orientation angles between the two films are shown. As the orientation of the two films changes from parallel to perpendicular, the transmission spectra change significantly.

[0114] Examples according to the present invention

[0115] Step 1: Extrusion of the Color Enhancement (CE) layer

[0116] The colored CE layer according to the present invention was extruded from a mixture of dye and polycarbonate (PC) resin (Panlite L-1250VX from Teijin) to a thickness of 300 μm.

[0117] Table 1 lists the formulations and amounts of dyes included in the CE layer according to the invention for green-grey, grey and brown lenses. Table 2 lists the characteristics of the absorption peaks of the dyes. All dyes are isotropic. Broadband dyes are selected to balance the color.

[0118] Table 1 Enco CE layer dye formula

[0119]

[0120]

[0121] Table 2 Dye absorption characteristics

[0122]

[0123] *Full width at half maximum (FWHM) calculation is only for peaks in the visible region (380 to 780 nm). For Solvent Yellow 93 (SY93), the maximum absorbance λ is about 390 nm, with a portion of the band less than 380 nm. Therefore, the FWHM is calculated using a modified version: FWHM for SY93 = (λ at 1 / 2 maximum - 390) × 2

[0124] Figure 3 The transmission spectrum of the gray-green CE layer and its polarization efficiency (PE) as a function of wavelength are shown. It can be noted that the PE of the CE layer is close to 0 over the entire wavelength range due to the use of isotropic dyes.

[0125] Step 2: Formation of the multilayer film 1 (PC / PVA / CE laminate) according to the invention

[0126] A stretched transparent PC layer 11 (ophthalmic grade PC from Teijin), a type 2 gray polarizing layer 12 made of polyvinyl alcohol (PVA) from Onbitt, and a CE layer 13 were laminated using PVA glue.

[0127] Step 3: Formation of lens including PC / PVA / CE laminate

[0128] A substrate made of polycarbonate (ophthalmic grade PC from Teijin) was injection molded onto the gray-green CE layer of the PC / PVA / CE laminate to obtain 3 types of prototype lenses.

[0129] Figure 4 The transmission spectrum of the prototype gray-green lens and the transmission spectrum of a standard Type 3 gray-green polarized lens (Essilor's Xperio gray-green polarized lens without color enhancement) are shown in FIG.

[0130] For grey, brown and grey-green lenses, the colour enhancement (chromaticity difference ΔC) of the colour-enhanced polarised lenses relative to standard polarised lenses (Xperio polarised lenses from Essilor) at 20,000 lux is included in Figure 5a-5c middle. Figure 5a-5c Also shown above is the change in hue (Δh) of the color enhanced polarized lens compared to the hue observed in the absence of any kind of filter.

[0131] ΔC was measured for 18 specific colors and the MacWhite card codes for these colors are given on the graph.

[0132] Color-enhanced polarized lenses achieve superior %ΔC compared to standard comparison lenses 平均 , 10.9% for gray lenses, 11.2% for brown lenses, and 7.7% for gray-green lenses. Moreover, these color enhancement values ​​are achieved while inducing only minimal color distortion. In fact, for gray lenses, |Δh 最大 | is only 12.6°, for brown lenses, |Δh 最大 | is only 13.4°, and for gray-green lenses, |Δh 最大 |Only 8.6°.

Claims

1. A color-enhanced polarizing multilayer film (1), comprising: - having a front and a back polarizing layer (12); - a first protective layer (11); - a second protective layer (13); as well as - one or more isotropic dyes contained in at least one of the first protective layer or the second protective layer; wherein the first protective layer is disposed on the front surface of the polarizing layer, and the second protective layer is disposed on the back surface of the polarizing layer, and wherein the one or more isotropic dyes account for at least 90 wt.% of the total content of dyes contained in the first protective layer and the second protective layer.

2. The multilayer film according to claim 1, wherein The one or more isotropic dyes account for at least 90 wt.% of the total content of dyes contained in the layers other than the polarizing layer.

3. The multilayer film according to claim 1 or 2, wherein Substantially all of the dye contained in the first protective layer and the second protective layer is contained in the first protective layer, or substantially all of the dye contained in the first protective layer and the second protective layer is contained in the second protective layer.

4. The multilayer film according to claims 1 to 3, wherein The dye contained in the first protective layer and the second protective layer does not substantially contain an anisotropic dye.

5. The multilayer film according to claims 1 to 4, wherein The one or more isotropic dyes contained in at least one of the first protective layer or the second protective layer include at least one narrow-band isotropic dye and optionally at least one broadband isotropic dye.

6. The multilayer film according to claim 5, wherein The at least one broadband isotropic dye is selected from the group consisting of Solvent Yellow 93, Solvent Orange 60, Solvent Red 52, Solvent Red 111, Solvent Red 169, Solvent Violet 13, Solvent Violet 14, Solvent Violet 31, Solvent Violet 36, Solvent Violet 38, Solvent Violet 50, Solvent Blue 101, Solvent Blue 104, Solvent Blue 138 and Solvent Green 3.

7. The multilayer film according to claim 5 or 6, wherein The at least one narrow-band isotropic dye exhibits a maximum of a narrow-band absorption peak at 400 to 700 nm in the layer of the multilayer film comprising it.

8. The multilayer film according to any one of claims 5 to 7, wherein The at least one narrow-band isotropic dye is selected from the group consisting of: Epolight 5841, Epolight 5819 and Epolight 6698.

9. The multilayer film according to any one of claims 1 to 8, wherein The first protective layer and the second protective layer independently comprise a thermoplastic polymer selected from polycarbonate, polyester, polyacrylate and a mixture thereof as a base material.

10. The multilayer film according to any one of claims 1 to 9, wherein The polarizing layer includes polyvinyl alcohol as a base material.

11. The multilayer film according to any one of claims 1 to 10, wherein The first protective layer is a uniaxially stretched layer.

12. An ophthalmic lens comprising the multilayer film of any one of claims 1 to 11 and a substrate injection molded onto the multilayer film.

13. A method for producing a multilayer film as claimed in any one of claims 1 to 11, comprising the steps of: - providing said polarizing layer; - extruding a first mixture comprising a first base material to obtain said first protective layer; - extruding a second mixture comprising a second base material to obtain said second protective layer; as well as - laminating the first protective layer, the polarizing layer and the second protective layer into the multilayer film; wherein the one or more isotropic dyes are contained in at least one of the first mixture or the second mixture; and The one or more isotropic dyes account for at least 90 wt.%, preferably at least 95 wt.%, and even more preferably at least 99 wt.% of the total content of dyes contained in the first mixture and the second mixture.

14. The method of claim 13, further comprising stretching the first protective layer, wherein the stretching is performed prior to lamination.

15. A method for producing an ophthalmic lens as claimed in any one of claims 1 to 11 from a multilayer film as claimed in any one of claims 1 to 11, the method comprising injection molding a substrate onto the multilayer film.

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