Method for preparing a sheet using a stretched polymer for thermoforming of the sheet and an injection molded ophthalmic lens comprising the sheet

Abstract

A method of forming an ophthalmic laminated lens, comprising: forming a flat laminate (100) by adhering a first stretched polymer layer (115) to a first side of a thermoplastic elastomer layer (120) and adhering a second polymer layer (125) to a second side of the thermoplastic elastomer layer (120), the first stretched polymer layer (115) having a thickness greater than 250 μm, the second polymer layer (125) having a thickness greater than 250 μm, and the thermoplastic elastomer layer (120) having a thickness in the range of 15 μm to 150 μm. m; thermoforming a flat laminate (100) into a curved laminate (105) having a preformed curvature; arranging the curved laminate (105) in a mold (145a); and molding the curved laminate (105) into a curved lens using a polymer melt (140) by setting the mold (145a, 145b) at a predetermined temperature and a predetermined pressure, wherein the temperature of the polymer melt (140) is higher than the stretching temperature of the first stretched polymer layer (115).

Description

Technical Field

[0001] The present disclosure relates to laminates for preventing contamination of injection mold cavities caused by outflow of thermoplastic elastomer-based optically functional film layers during lens manufacturing. Background Art

[0002] The "background" description provided herein is intended to generally present the context of the present disclosure. The work of the presently named inventors is neither explicitly nor implicitly admitted to be prior art against the present disclosure to the extent that the work described in this background section, and aspects of this description that may not have been identified as prior art at the time of filing, is prior art against the present disclosure.

[0003] Functional optical films and / or laminates can be molded (formed) and overmolded into lenses for photochromic applications, polarizer applications, or other functional applications. This includes methods of making laminated constructions, molding laminates into curved sheets, and injection molding to form lenses for health or light management applications.

[0004] Injection molding of polymers such as polycarbonate or polyamide can be used to make prescription or non-corrective eyeglass lenses. This polymer injection molding method can be extended to overmolding thin, multi-layer laminate structures having a central functional film of a predetermined material that will change the overall function of the resulting lens. For example, a method of making a corrective or non-corrective polarized sunglass lens can utilize a multi-layer laminate that includes a layer impregnated with a photochromic dye and / or a polarizing dye as the central functional film.

[0005] The use of thermoplastic elastomer (TPE) based materials in the construction of laminated sheets can provide certain advantages (e.g., soft polymer segments, ductility, chemical compatibility with additives, etc.), but these advantages may lead to difficulties associated with the production of the final lens. When injection molding a TPE based laminated sheet onto the front (convex) power surface of a lens substrate, the high temperature and pressure in the mold can cause the softened TPE material to be squeezed and flow outward from the unrestricted edge of the sheet, resulting in mold (including inserts and mold cavities) contamination. This outflow (edge ​​seepage, leakage) is related to the plastic / viscous flow of the center film layer at high temperature and the pressure applied to the surface of the sheet. Therefore, there is a need for a method for producing lenses by injection molding without contaminating the mold. Summary of the invention

[0006] The present disclosure relates to a method for forming an ophthalmic laminated lens, comprising: forming a flat laminate by adhering a first stretched polymer layer to a first side of a thermoplastic elastomer layer and adhering a second polymer layer to a second side of the thermoplastic elastomer layer, the first stretched polymer layer having a thickness greater than 250 μm, the second polymer layer having a thickness greater than 250 μm, and the thermoplastic elastomer layer having a thickness in a range of 15 μm to 150 μm; thermoforming the flat laminate into a curved laminate having a preformed curvature; arranging the curved laminate in a mold; and molding the curved laminate into a curved lens with a polymer melt by setting the mold at a predetermined temperature and a predetermined pressure, wherein the temperature of the polymer melt is higher than the stretching temperature of the first stretched polymer layer.

[0007] The present disclosure also relates to an ophthalmic lens laminate comprising: a first stretched polymer layer having a thickness greater than 250 μm; a second polymer layer having a thickness greater than 250 μm; and a thermoplastic elastomer layer having a thickness in the range of 15 μm to 150 μm, the thermoplastic elastomer layer being disposed between the first stretched polymer layer and the second polymer layer, the thermoplastic elastomer layer being bonded to the first stretched polymer layer on the first side of the thermoplastic elastomer and to the second polymer layer on the second side of the thermoplastic elastomer layer.

[0008] It should be noted that this Summary of the Invention section does not describe in detail every embodiment and / or progressively novel aspect of the present disclosure or claimed invention. Rather, this Summary of the Invention only provides a preliminary discussion of different embodiments and corresponding novel points. For additional details and / or possible perspectives of the present invention and embodiments, the reader is referred to the Detailed Description section of the present disclosure and the corresponding drawings discussed further below. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Various embodiments of the present disclosure, presented as examples, will be described in detail with reference to the following drawings, in which like reference numerals refer to like elements, and in which:

[0010] Figure 1A is a schematic diagram of a flat laminate sheet according to an embodiment of the present disclosure.

[0011] Figure 1B is a schematic diagram of a thermoformed laminate sheet according to an embodiment of the present disclosure.

[0012] Figure 1C is a schematic diagram of a female mold insert according to an embodiment of the present disclosure.

[0013] Figure 1D is a schematic diagram of a molding device according to an embodiment of the present disclosure.

[0014] Figure 2A is a schematic diagram of the layers in a flat laminate sheet according to an embodiment of the present disclosure.

[0015] Figure 2B is a schematic diagram of the layers in a flat laminate sheet including an asymmetrically stretched polymer structure according to an embodiment of the present disclosure.

[0016] Figure 2C is a schematic diagram of the layers in a flat laminate sheet including a symmetrically stretched polymer structure according to an embodiment of the present disclosure.

[0017] Figure 3A is a schematic diagram of a thermoformed laminate sheet having a stretch polymer for the first layer according to an embodiment of the present disclosure.

[0018] Figure 3B is a schematic diagram of a thermoformed laminate sheet having a stretched polymer for both the first layer and the second layer according to an embodiment of the present disclosure.

[0019] Figure 3C is a schematic top view of a flat laminate sheet before and after uniaxial shrinkage according to an embodiment of the present disclosure.

[0020] Figure 3D is a schematic top view of a flat laminate sheet before and after biaxial shrinkage according to an embodiment of the present disclosure.

[0021] Figure 4 is a flow chart of a method of manufacturing an ophthalmic lens according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0022] The following disclosure provides many different embodiments or examples for implementing the different features of the proposed subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are only examples and are not intended to be limiting. For example, forming a first feature on or on a second feature in the following description may include an embodiment in which the first feature and the second feature are directly contacted and formed, and may also include an embodiment in which an additional feature may be formed between the first feature and the second feature, so that the first feature and the second feature may not be in direct contact. In addition, the present disclosure may repeat the reference numerals and / or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself specify the relationship between the various embodiments and / or configurations discussed. Further, for ease of description, spatial relative terms such as "top", "bottom", "below", "below", "lower", "above", "above", etc. may be used herein to describe the relationship between an element or feature as shown in the figure and another (multiple) element or feature. In addition to the orientation depicted in the figure, the spatial relative terms are intended to include different orientations of the device when used or operated. The device may be oriented in other ways (rotated 90 degrees or in other orientations) and the spatial relative descriptors used herein may also be interpreted accordingly.

[0023] For the sake of clarity, the order of discussion of the different steps as described herein has been presented. Generally, these steps can be performed in any suitable order. In addition, although each of the different features, techniques, configurations, etc. herein can be discussed in different places of the present disclosure, it is intended that each concept can be performed independently of each other or in combination with each other. Therefore, the present disclosure can be implemented and viewed in many different ways.

[0024] The die cutting tool can be used to cut the sheets from the flat laminated sheet into circular or oval disks. These flat laminated sheets are then thermoformed into spherical dome shapes. The diameter of the flat laminated sheet is determined by considering at least one or more of the following: the desired lens diameter (e.g., 70 mm, 76 mm, 80 mm, etc.), the base curve of the thermoformed sheet (e.g., 0.25D, 1.75D, 3.00D, 4.00D, 4.50D, 5.50D, 6.00D, 6.50D, 7.25D, 8.00D, etc.), and the base curve of the mold insert (e.g., 1.75D, 2.25D, 3.25D, 4.25D, 5.50D, 6.50D, 7.50D, 8.50D, etc.). The base curve of the mold insert can be the same base curve as the convex power surface of the lens.

[0025] Thermoplastic elastomers provide many beneficial properties when used as the primary matrix of the functional core layer. The soft polymer segments provide flexibility and additive compatibility, while the harder segments provide stiffness and hardness. However, thermoplastic elastomers (e.g., aliphatic thermoplastic polyurethanes, polyether block amide polyurethanes, etc.) are a class of polymers that deform and flow under typical thermoforming and molding operations, resulting in edge oozing and leakage.

[0026] The methods disclosed herein at least address the challenges associated with optically functional thermoplastic elastomer (TPE) materials flowing out from between the outer transparent polymer film layers (e.g., transparent polycarbonate film layers) during any sheet processing step. Under the high temperature and pressure conditions of injection molding, this inner layer softens and flows out of the laminate sheet in a radial direction, thereby contaminating the mold cavity. By incorporating a unidirectional (MO) or biaxially oriented (BO) stretched polymer film (e.g., stretched polycarbonate film) on the final concave surface of the laminate sheet, the diameter of this stretched film can shrink (due to heat) during thermoforming and / or injection overmolding, causing the edge of the film to retract from the edge of the lens (move away from the edge of the lens), while leaving the cooler polymer film (e.g., polycarbonate film) on the convex side at or close to its original diameter. This can reduce the amount of TPE that can seep or leak out from the edge of the laminate and contaminate the mold cavity, the gap area between the female insert and the cavity wall, and the insert surface. In particular, clear stretched polymer films (e.g., clear stretched polycarbonate films) on the convex and concave sides of the TPE optical film can be used to produce flat laminates, curved sheets, and optically functional (e.g., photochromic) lenses (prescription or non-corrective lenses).

[0027] Figure 1A is a schematic diagram of a flat laminate sheet 100 according to an embodiment of the present disclosure. Figure 1A The diameters and base curves of various components involved in cutting, thermoforming and forming are shown. In one embodiment, the diameter d of the circular flat sheet is fw The length is the same as the arc length of the flat laminate sheet 100 after thermoforming.

[0028] Figure 1B FIG. 1 is a schematic diagram of a thermoformed laminate sheet 105 according to an embodiment of the present disclosure. In one embodiment, the rope length d of the thermoformed laminate sheet 105 is TF It may be of approximately the same diameter as the lens.

[0029] Figure 1C is a schematic diagram of a female mold insert 130 according to an embodiment of the present disclosure. In one embodiment, the diameter of the lens can be determined by, for example, the diameter d of the female mold insert 130. 嵌件 Therefore, the chord length (d TF ) and the diameter (d嵌件 ) both of which may be smaller in diameter than the diameter (d fw ). Due to the difference in base arcs of the flat laminate sheet 100 and the female mold insert 130 , the arc length of the female mold insert 130 is equal to or greater than the arc length of the thermoformed laminate sheet 105 .

[0030] Figure 1D is a schematic diagram of a molding apparatus according to an embodiment of the present disclosure. In one embodiment, the molding apparatus may include a first mold side 145a, a second mold side 145b, a female mold insert 130, and a male mold insert 135. The first mold side 145a and the second mold side 145b may each include a hollow portion, wherein the female mold insert 130 and the male mold insert 135 may be removably disposed in the hollow portion. Figure 1D As shown, a first mold side 145a including a female mold insert 130 can be configured to be coupled to a second mold side 145b including a male mold insert 135. When coupled, the female mold insert 130 and the male mold insert 135 can form a cavity connected to a hollow line formed by the coupling of the first and second mold sides 145a, 145b. This line can be configured to receive a polymer, for example, by a screw feeder or similar device. The cavity can be configured to receive a thermoformed laminate sheet 105. The curvature of the female mold insert 130 and the curvature of the male mold insert 135 can determine the lens power of the resulting lens. For a semi-finished lens, the curvature along the convex side of the lens is fixed, while the concave side of the lens can be modified after molding, such as by grinding and polishing. It should be noted that multiple lines for receiving polymer can be connected so that injecting polymer from one source can fill multiple mold devices with a single injection and allow multiple lenses to be manufactured in parallel.

[0031] Prior to being placed in a forming device, the flat laminate sheet 100 may be thermoformed into a spherical dome-shaped thermoformed laminate sheet 105, such as by a thermoformer. During thermoforming, the flat laminate sheet 100 may be placed on a heated thermoforming insert, and a vacuum force may be applied to secure the flat laminate sheet 100 to the thermoforming insert. By adjusting the temperature of the applied heat and the force of the applied vacuum, the flat laminate sheet 100 may be formed into the curved shape of the thermoforming insert to produce a thermoformed laminate sheet 105.

[0032] In one embodiment, the flat laminate sheet 100 may include a first layer 115, a center layer 120, and a second layer 125. Figure 1D As shown, thermoforming the flat laminate sheet 100 can produce a curved structure in which the first layer 115 is the concave side and the second layer 125 is the convex side.

[0033] In one embodiment, the thermoformed laminate sheet 105 can be arranged in a forming device adjacent to a female mold insert 130, wherein the convex side (i.e., the second layer 125) of the thermoformed laminate sheet 105 is adjacent to the female mold insert 130. The thermoformed laminate sheet 105 rests on the female mold insert 130, and the edge of the thermoformed laminate sheet 105 extends beyond the edge of the female mold insert 130 (d TF =d 嵌件 ) to secure the thermoformed laminate sheet 105 in the mold cavity. When the base curve of the thermoformed laminate sheet 105 is smaller than the base curve of the female mold insert 130, a flat laminate sheet 100 with a smaller diameter can be used to maintain a constant rope length (or lens diameter), that is, the rope length is preferably equal to the diameter of the female mold insert 130 for all base curves of the thermoformed laminate sheet 105 to prevent the thermoformed laminate sheet 105 from falling out of the cavity during the loading operation. This is particularly important when a vacuum is used and a seal is required between the thermoformed laminate sheet 105 and the female mold insert 130.

[0034] It should also be noted that the perimeter of the flat laminate sheet 100 may be greater than the perimeter of the thermoformed laminate sheet 105. fw / d TF Above a predetermined ratio, edge deformation occurs, and the extra length at the edge of the flat laminate sheet 100 can be accommodated by compression, out-of-plane deformation, warping, or crease formation at the edge of the thermoformed laminate sheet 105.

[0035] The flat laminate sheet 100 can be thermoformed to a medium base curve (4.00D, radius of curvature diopters) to a high base curve (8.50D), wherein the diameter d of the flat laminate sheet 100 is fw Much larger than the diameter d of the thermoformed laminate sheet 105 TF . The ability to successfully render a laminated structure (e.g., a flat laminated sheet 100) without failure under tensile and compressive forces is fundamentally based on the mechanical properties of the laminated composition. Mechanical properties such as stiffness, ductility, and elasticity play a major role in the thermoforming of the flat laminated sheet 100. The use of softer and more ductile materials (>50 microns) for the center layer 120 increases the likelihood of defects. Commonly observed sheet defects include warping and crease formation at any alignment or centering protrusions. This article describes increasing the stiffness of the flat laminated sheet 100 by adjusting the thickness of the layer. It will be appreciated that known devices and methods can be used to thermoform the flat laminated sheet 100, such as the Italian LEMA machine, which gradually increases the curvature of the flat laminated sheet 100 under applied heat.

[0036] Figure 2A1 is a schematic diagram of each layer in a flat laminated sheet 100 according to an embodiment of the present disclosure. It is understood that techniques known to those skilled in the art can be used to manufacture the flat laminated sheet 100. In one example, adhesive lamination can be utilized, wherein an adhesive is used to bond the first layer 115 and the second layer 125 to the center layer 120 and to bring it close by a pair of nip rollers. The nip rollers can be configured to promote the spreading of the adhesive, thereby controlling the thickness of the flat laminated sheet 100 and being used to squeeze the layers together. In another example, extrusion lamination can be utilized, wherein the hot melt center layer 120 is sandwiched between the first layer 115 and the second layer 125. The thickness can be adjusted by setting the nip roller gap in this example. In another example, adhesive coating lamination can be utilized, wherein the center layer 120 solvent can be cast on a carrier film and dried. In this state, the center layer 120 is more viscous and sticky, thereby allowing the center layer to be transferred from the carrier film to the first layer 115 and the second layer 125 using a pair of nip rollers configured to seal the layers together under pressure. Thus, as described above, in some examples, an optional adhesive may be disposed between the central layer 120 and the outer first and second layers 115, 125. In other examples, the layers may be directly bonded.

[0037] The center layer 120 can be an optically functional thermoplastic elastomer resin. In one example, the center layer 120 can be a thermoplastic polyurethane (TPU). In another example, the center layer 120 can be a semi-crystalline polyether block polyamide (PEBA). It is worth noting that optical additives (e.g., photochromic dyes, coloring dyes, selective wavelength dye absorbers, electrochromic dyes, etc.) can be mixed with the center layer 120 to produce an optically functional film. The first layer 115 and the second layer 125 can be, for example, polycarbonate, cellulose esters (e.g., triacetyl cellulose), acrylic resins, cyclic olefin copolymers, etc., and are optically transparent and have little haze.

[0038] Thermoplastic elastomers can provide beneficial properties when used as the main matrix of the center layer 120. Block copolymers can include soft polymer segments that provide flexibility and additive compatibility, while harder segments provide stiffness and hardness. However, TPEs (e.g., amorphous thermoplastic polyurethanes, semi-crystalline polyether block amides, etc.) are a class of polymers that are easily deformed and flowed under typical thermoforming and molding operations, resulting in edge oozing and leakage. This may lead to contamination of the molding device, such as contamination on the cavity wall and the surface of the concave and convex inserts 130, 135. This may cause the surface of the lens (convex surface and outer edge of the lens) of the final manufacturing to be contaminated, which can cascade downstream during the manufacturing process, thereby contaminating other instruments, such as wet coating systems. In addition, TPE may fill the gap volume between the first and second mold sides 145a, 145b and the concave mold inserts and convex mold inserts 130, 135, making it difficult to remove the concave mold inserts and convex mold inserts 130, 135 from the molding device.

[0039] Figure 2B is a schematic diagram of the layers in a flat laminated sheet 100 including an asymmetrically stretched polymer structure according to an embodiment of the present disclosure. In one embodiment, the flat laminated sheet 100 may include a first layer 115, a center layer 120, and a second layer 125, wherein the first layer 115 is a stretched polymer. For example, the first layer 115 is a stretched polycarbonate, wherein the polycarbonate can be uniaxially or biaxially stretched. The thickness of the first layer 115 can be greater than 250 μm. For example, the thickness of the first layer 115 can be in the range of 300 μm to 800 μm. The thickness of the second layer 125 can be greater than 250 μm. For example, the thickness of the second layer 125 can be in the range of 300 μm to 800 μm. The thickness of the center layer 120 can be in the range of, for example, 15 μm to 150 μm. The flat laminate 100 (and the thermoformed laminate 105) may also include alignment tabs to prevent the flat laminate 100 from moving over the edge of the lens near the alignment bosses and to keep the thermoformed laminate 105 centered when placed in the female molding insert 130. This structure may be used in Figure 3A middle.

[0040] Stretched polymers (e.g., stretched polycarbonates) can be manufactured, for example, by stretching on a series of rollers set at a predetermined stretching temperature and stretching rate. The predetermined stretching temperature can be, for example, equal to or greater than the glass transition temperature of the polymer (e.g., polycarbonate). As the polymer (e.g., polycarbonate) moves downstream in the roller series, the roller heating can be gradually increased to increase the temperature of the polymer (e.g., polycarbonate) so as to promote the elongation of the film. For uniaxially stretched polymers (e.g., uniaxially stretched polycarbonates), the rollers can stretch the polymer (e.g., polycarbonate) along the direction in which the polymer (e.g., polycarbonate) travels between the rollers. For biaxially stretched polymers (e.g., biaxially stretched polycarbonates), the uniaxially stretched polymer (e.g., uniaxially stretched polycarbonate) can be stretched in a second direction transverse to the direction in which the polymer (e.g., polycarbonate) travels between the rollers. This second transverse stretching can be performed, for example, by a series of clamping devices that are attached to the edge of the polymer film (e.g., polycarbonate film) and pulled apart in the second direction. This pulling can be performed in an oven set at a predetermined stretching temperature to increase the temperature of the polymer (e.g., polycarbonate) so as to promote elongation of the film. By stretching the polymer (e.g., polycarbonate) at the predetermined stretching temperature and then cooling the polymer (e.g., polycarbonate), the polymer (e.g., polycarbonate) remains in a stretched state until the polymer (e.g., polycarbonate) is exposed to the predetermined stretching temperature again, so that the stretched polymer (e.g., stretched polycarbonate) can reversibly relax and shrink.

[0041] Figure 2C is a schematic diagram of the layers in a flat laminated sheet 100 including a symmetrically stretched polymer structure according to an embodiment of the present disclosure. In one embodiment, the flat laminated sheet 100 may include a first layer 115, a center layer 120, and a second layer 125, wherein the first layer 115 and the second layer 125 are stretched polymers. For example, the first layer 115 is a stretched polycarbonate. The thickness of the first layer 115 may be greater than 250 μm. For example, the thickness of the first layer 115 may be in the range of 300 μm to 800 μm. The thickness of the second layer 125 may be greater than 250 μm. For example, the thickness of the second layer 125 may be in the range of 300 μm to 800 μm. The thickness of the first layer 115 and the second layer 125 may be approximately equal, for example within a manufacturing tolerance of 5 μm. The thickness of the center layer 120 may be in the range of, for example, 15 μm to 150 μm. The flat laminated sheet 100 (and the thermoformed laminated sheet 105) may also include alignment protrusions. This structure can be used in Figure 3B middle.

[0042] As previously described, the flat laminated sheet 100 can be thermoformed into a spherical dome-shaped thermoformed laminated sheet 105, such as by a thermoformer, before being placed in a forming device. During the thermoforming process, the non-stretched polymer second layer 125 (e.g., non-stretched polycarbonate second layer 125) of the flat laminated sheet 100 can be arranged on a curved former surface (e.g., a thermoformer insert), and the stretched polymer first layer 115 (e.g., stretched polycarbonate first layer 115) of the flat laminated sheet 100 can be exposed to a heat source in the thermoformer.

[0043] In one embodiment, only the first layer 115 is a stretched polymer (e.g., stretched polycarbonate), and when the heat source causes the temperature of the stretched polymer first layer 115 (e.g., stretched polycarbonate first layer 115) to rise above a predetermined stretch annealing temperature (i.e., stretch freezing temperature), the stretched polymer first layer 115 (e.g., stretched polycarbonate first layer 115) on the concave side of the thermoformed laminate sheet 105 can partially shrink in one (for uniaxial) or both (for biaxial) axes. This is achievable because the TPE material of the center layer 120 softens, deforms, and / or flows before reaching the predetermined stretch annealing temperature, which relieves the interdependence of the second convex layer 125 and the first concave layer 115. As a result, the diameter of the outer second convex layer 125 is slightly larger than the diameter of the inner first concave layer 115 (on one or both film axes).

[0044] In one embodiment, a heating source in the thermoforming machine is configured to maintain the temperature of the stretched polymer first layer 115 (eg, stretched polycarbonate first layer 115) below a predetermined stretching temperature to prevent partial or complete shrinkage.

[0045] Figure 3A1 is a schematic diagram of a thermoformed laminate sheet 105 having a stretched polymer for a first layer 115 according to an embodiment of the present disclosure. In one embodiment, the thermoformed laminate sheet 105 is arranged in a mold cavity so that the stretched polymer for the first layer 115 is adjacent to the location where the polymer melt 140 will be injected into the mold cavity. Starting from the mold opening device, the thermoformed laminate sheet 105 is arranged adjacent to the female mold insert 130. A first mold side 145a in which the female mold insert 130 is accommodated is coupled together with a second mold side 145b in which the male mold insert 135 is accommodated. This can be performed by, for example, a hydraulic or electric press to push one of the mold sides 145a, 145b against the other. After coupling the mold sides 145a, 145b, a polymer melt 140 (e.g., molten polycarbonate) is injected into the mold cavity of the mold device, between the thermoformed laminate sheet 105 and the male mold insert 135. In some implementations, the polymer melt 140 includes a transparent or translucent thermoplastic material, such as polycarbonate, thermoplastic polyurethane, polyacrylate, polyester, copolyester, polymethacrylate, poly(methyl methacrylate), polystyrene, polyamide, polysulfone, polyphenylsulfone, polyetherimide, polypentene, polyolefin, ionomer, ethylene methacrylic acid, cyclic olefin copolymer, acrylonitrile, styrene maleic anhydride, copolymers thereof, or derivatives or mixtures thereof.

[0046] The polymer melt 140 slowly cools inside the mold over time, bonds with the thermoformed laminate sheet 105, and can be ejected from the mold assembly when the mold sides 145a, 145b separate. The mold sides 145a, 145b can be independently thermally controlled. The female and male mold inserts 130, 135 can also be independently thermally controlled or rely on the mold sides 145a, 145b to dissipate heat. That is, the female and male mold inserts 130, 135 can be thermally coupled to the mold sides 145a, 145b, and the mold sides 145a, 145b can be large enough heat sinks to absorb the heat transferred from the polymer melt 140 to the female and male mold inserts 130, 135 during cooling.

[0047] In one embodiment, the stretched polymer first layer 115 may shrink due to raising the temperature of the stretched polymer above a predetermined stretch annealing (freezing) temperature by heat transfer from the polymer melt 140. This stretched polymer first layer 115 may shrink from the edge of the non-shrinking second layer 125 on the opposite side of the thermoformed laminate sheet 105. The shrinking direction of the first layer 115 may be along the direction of stretching of the polymer during manufacturing. The cooler temperature of the female mold insert 130 thermally coupled to the first mold side 145a is below the predetermined stretch annealing temperature, so the temperature of the second layer 125 can be maintained below the predetermined stretch annealing temperature. The temperature of the first mold side 145a (and by means of heat conduction, the temperature of the female mold insert 130) can be maintained much cooler (e.g., >120°C cooler) by a cooling device (e.g., by circulating a chilled water-based or oil-based fluid inside the first mold side 145a). The temperature of the second mold side 145b (and by means of heat conduction, the temperature of the male mold insert 135) can be similarly maintained.

[0048] The mechanism for preventing the center layer 120 from flowing out (edge ​​oozing, leakage, etc.) is described as follows. The stretched polymer first layer 115 shrinks due to the heat from the polymer melt 140, while the diameter of the second layer 125 remains relatively unchanged. The stretched polymer first layer 115 pulls the center layer 120 away from the edge of the thermoformed laminate sheet 105 as it shrinks. This shrinkage prevents the TPE material of the center layer 120 from overflowing the edge of the resulting lens and contaminating the resulting lens itself. This shrinkage also prevents the TPE material of the center layer 120 from reaching and contaminating the side walls of the cavity of the molding device. The shrinkage of the first layer 115 and the center layer 120 can also allow the polymer melt 140 to fill along the edges of the first layer 115 and the center layer 120, thereby essentially encapsulating the first layer 115 and the center layer 120 in the polymer melt 140.

[0049] Figure 3B is a schematic diagram of a thermoformed laminate sheet 105 having a stretched polymer for both a first layer 115 and a second layer 125 according to an embodiment of the present disclosure. In one embodiment, the thermoformed laminate sheet 105 is arranged in a mold cavity such that the stretched polymer for the first layer 115 is adjacent to where a polymer melt 140 will be injected into the mold cavity, and the stretched polymer for the second layer 125 is arranged adjacent to a female mold insert 130.

[0050] Figure 3C1 is a schematic top view of a uniaxially stretched flat laminate sheet 100a before and after uniaxial contraction according to an embodiment of the present disclosure. As shown, after thermoforming and injection molding to form a uniaxially stretched lens 195a, the stretched polymer in the first layer 115 can be uniaxially contracted in a single direction, thereby causing the opposite edges of the first layer 115 (and concomitantly, the center layer 120) to retract from the diameter of the uniaxially stretched lens 195a along the contraction direction.

[0051] Figure 3D 1 is a top view schematic diagram of a biaxially stretched flat laminate sheet 100b before and after biaxial contraction according to an embodiment of the present disclosure. As shown, after thermoforming and injection molding to form a biaxially stretched lens 195b, the stretched polymer in the first layer 115 can be biaxially contracted, causing the entire circumference of the first layer 115 (and concomitantly, the center layer 120) to retract from the diameter of the biaxially stretched lens 195b.

[0052] Figure 41 is a flow chart of a method for manufacturing an ophthalmic lens according to an embodiment of the present disclosure. In step S401, a flat laminated sheet 100 is formed. For example, the flat laminated sheet 100 can be formed by adhesive lamination, extrusion lamination, adhesive coating lamination or any other known method. The flat laminated sheet 100 can include, for example, three layers, wherein the center layer 120 is a thermoplastic elastomer and one or both of the first and second layers 115, 125 are stretched polymers. In step S403, the flat laminated sheet 100 is formed into a thermoformed laminated sheet 105. The thermoforming device can be used to modify the curvature and shape of the flat laminated sheet 100 before molding in the molding device. In step S405, the thermoformed laminated sheet 105 is arranged in the molding device. For example, the thermoformed laminated sheet 105 is placed adjacent to the concave mold insert 130 so that the convex side of the thermoformed laminated sheet 105 faces the concave mold insert 130. The female mold insert 130 can fix the thermoformed laminated sheet 105 by vacuum force. The mold sides 145a, 145b can be pushed together to connect and form a seal. In step S407, the polymer melt 140 can be injected into the mold cavity of the mold device, between the thermoformed laminated sheet 105 and the male mold insert 135. In step S409, the lens is molded by cooling the polymer melt 140 in the mold device. The heat and pressure from the polymer melt 140 can be transferred to the stretched polymer of the first layer 115, thereby causing the first layer 115 to shrink and retract from the edge of the lens. The shrinkage of the first layer 115 can cause a concomitant retraction of the edge of the center layer 120. The heat from the polymer melt 140 can additionally heat the thermoformed laminated sheet 105 so as to further mold the thermoformed laminated sheet 105 according to the curvature of the female mold insert 130. It will be appreciated that the method may be used to form "flat" eyeglass lenses, plano eyeglass lenses, prescription eyeglass lenses, and "high-rimmed" sunglasses and goggles.

[0053] As previously described, the stretched polymer can be a stretched polycarbonate. In addition, the stretched polymer can be uniaxially or biaxially stretched. For biaxially stretched polymers, two-dimensional shrinkage during lens manufacturing can include the following advantages: i) keeping the thermoformed laminate sheet 105 centered between the female and male mold inserts 130, 135, ii) providing a spacing distance between the edges of the thermoformed laminate sheet 105 and the side walls of the mold device cavity, iii) allowing the first layer 115 and the center layer 120 to be encapsulated by the injected polymer melt 140 during shrinkage, iv) fixing the leading edge of the thermoformed laminate sheet 105 in place against the female mold insert 130 when filling the cavity, v) preventing the thermoformed laminate sheet 105 from being displaced away from the initial position before filling, and vi) preferentially aligning the thermoformed laminate sheet 105 within the cavity by the alignment protrusions.

[0054] General advantages include the following: i) a simple, low-cost sheet die-cutting process that produces clean sheet edges (almost no TPE at the sheet edges); ii) the sheet design follows lens molding through a standard PC polarized lens overmolding process; iii) the encapsulated run-off area at the lens edge can be retained as part of the final lens product after injection molding, or it can be removed by grinding it (shaping); iv) the final lens product made with this sheet encapsulation method can be a photochromic lens, a polarized lens, or any other functional lens containing contaminating materials or adhesives in any film or laminate structure; v) the contaminating center layer 120 can be a photochromic film or adhesive that melts and flows under the influence of heat and pressure; and vi) the method can be used for sheet injection molding, overmolding, mold casting, or surface casting processes.

[0055] In the foregoing description, specific details have been set forth, such as the specific geometry of the processing system and the description of the various components and processes used therein. However, it should be understood that the technology herein can be practiced in other embodiments that are separated from these specific details, and these embodiments are for illustrative rather than limiting purposes. The embodiments disclosed herein have been described with reference to the accompanying drawings. Similarly, for the purpose of explanation, specific numbers, materials, and configurations have been set forth to provide a thorough understanding. However, the embodiments can be practiced without these specific details. Components having substantially the same functional structure are represented by the same reference numerals, so any redundant descriptions can be omitted.

[0056] Various techniques have been described as multiple discrete operations to help understand various embodiments. The order of description should not be interpreted as implying that these operations must rely on the order. In fact, these operations do not need to be performed in the order presented. The described operations can be performed in an order different from the described embodiments. In additional embodiments, various additional operations can be performed and / or the described operations can be omitted.

[0057] It will also be appreciated by those skilled in the art that many changes may be made to the operation of the above-mentioned techniques while still achieving the same objectives of the present invention. Such changes are intended to be covered by the scope of the present disclosure. Therefore, the foregoing description of the embodiments of the present invention is not intended to be restrictive. Rather, any limitations to the embodiments of the present invention are set forth in the following claims.

[0058] Embodiments of the present disclosure may also be described as follows in brackets.

[0059] (1) A method for forming an ophthalmic laminated lens, comprising forming a flat laminate by adhering a first stretched polymer layer to a first side of a thermoplastic elastomer layer and adhering a second polymer layer to a second side of the thermoplastic elastomer layer, the first stretched polymer layer having a thickness greater than 250 μm, the second polymer layer having a thickness greater than 250 μm, and the thermoplastic elastomer layer having a thickness in the range of 15 μm to 150 μm; thermoforming the flat laminate into a curved laminate having a preformed curvature; arranging the curved laminate in a mold; and molding the curved laminate into a curved lens with a polymer melt by setting the mold at a predetermined temperature and a predetermined pressure, wherein the temperature of the polymer melt is higher than the stretching temperature of the first stretched polymer layer.

[0060] (2) A method as described in (1), wherein the mold includes a female mold insert and a male mold insert, the curved laminate is arranged in the mold so that the second polymer layer is adjacent to the female mold insert, and the polymer melt is injected between the first stretched polymer layer of the curved laminate and the male mold insert.

[0061] (3) The method according to (1) or (2), wherein the first stretched polymer is a uniaxially stretched polycarbonate.

[0062] (4) The method according to any one of (1) to (2), wherein the first stretched polymer is a biaxially stretched polycarbonate.

[0063] (5) The method according to any one of (1) to (4), wherein the second polymer layer is a stretched polymer and is uniaxially stretched.

[0064] (6) The method according to any one of (1) to (4), wherein the second polymer layer is a stretched polymer and is biaxially stretched.

[0065] (7) The method according to any one of (1) to (6), wherein the thickness of the first stretched polymer layer and the thickness of the second polymer layer are each in the range of greater than 250 μm to 800 μm.

[0066] (8) The method according to any one of (1) to (7), wherein the thickness of the first stretched polymer layer is substantially equal to the thickness of the second polymer layer.

[0067] (9) The method according to any one of (1) to (8), wherein the thickness of the thermoplastic elastomer layer is in the range of 25 μm to 75 μm.

[0068] (10) The method of any one of (1) to (9), wherein the thermoformed curved laminate has a base curve greater than 5.0D.

[0069] (11) The method according to any one of (1) to (10), wherein the material of the thermoplastic elastomer layer is thermoplastic polyurethane or polyether block polyamide.

[0070] (12) The method according to any one of (1) to (11), wherein after heating to a temperature higher than the stretching temperature, the diameter of the first stretched polymer layer is narrowed to be smaller than the diameter of the second polymer layer.

[0071] (13) The method according to any one of (1) to (12), wherein the polymer melt encapsulates the first stretched polymer layer and the thermoplastic elastomer layer on the second polymer layer.

[0072] (14) An ophthalmic lens laminate comprising a first stretched polymer layer having a thickness greater than 250 μm; a second polymer layer having a thickness greater than 250 μm; and a thermoplastic elastomer layer having a thickness in the range of 15 μm to 150 μm, the thermoplastic elastomer layer being disposed between the first stretched polymer layer and the second polymer layer, the thermoplastic elastomer layer being bonded to the first stretched polymer layer on a first side of the thermoplastic elastomer and to the second polymer layer on a second side of the thermoplastic elastomer layer.

[0073] (15) The ophthalmic lens laminate of (14), wherein the thickness of the first stretched polymer layer is substantially equal to the thickness of the second polymer layer.

[0074] (16) The ophthalmic lens laminate of (14) or (15), wherein the thickness of the first stretched polymer layer and the thickness of the second polymer layer are each in the range of greater than 250 μm to 800 μm.

[0075] (17) The ophthalmic lens laminate according to any one of (14) to (16), wherein the first stretched polymer is a uniaxially stretched polycarbonate.

[0076] (18) The ophthalmic lens laminate according to any one of (14) to (16), wherein the first stretched polymer is a biaxially stretched polycarbonate.

[0077] (19) The ophthalmic lens laminate according to any one of (14) to (18), wherein the thickness of the thermoplastic elastomer layer is in the range of 25 μm to 75 μm.

[0078] (20) The ophthalmic lens laminate according to any one of (14) to (19), wherein the material of the thermoplastic elastomer layer is thermoplastic polyurethane or polyether block polyamide.

Claims

1. A method of forming an ophthalmic laminated lens, comprising: forming a flat laminate by adhering a first stretched polymer layer to a first side of a thermoplastic elastomer layer and adhering a second polymer layer to a second side of the thermoplastic elastomer layer, the first stretched polymer layer having a thickness greater than 250 μm, the second polymer layer having a thickness greater than 250 μm, and the thermoplastic elastomer layer having a thickness in a range of 15 μm to 150 μm; thermoforming the flat laminate into a curved laminate, the curved laminate having a preformed curvature; placing the curved laminate in a mold cavity such that the stretched polymer for the first layer is adjacent to where the polymer melt will be injected into the cavity; as well as The curved laminate is formed into a curved lens using the polymer melt by the mold set at a predetermined temperature and a predetermined pressure, wherein, The temperature of the polymer melt is higher than the stretching temperature of the first stretched polymer layer.

2. The method of claim 1, wherein: The mold comprises a female mold insert and a male mold insert, placing the curved laminate in the mold such that the second polymer layer is adjacent to the female mold insert, and The polymer melt is injected between the first stretched polymer layer of the curved laminate and the male mold insert.

3. The method of claim 2, wherein: The first stretched polymer is a uniaxially stretched polycarbonate.

4. The method of claim 2, wherein: The first stretched polymer is a biaxially stretched polycarbonate.

5. The method of claim 2, wherein: The second polymer layer is a stretched polymer and is uniaxially stretched.

6. The method of claim 2, wherein: The second polymer layer is a stretched polymer and is biaxially stretched.

7. The method of claim 1, wherein: The thickness of the first stretched polymer layer and the thickness of the second polymer layer are each in a range of greater than 250 μm to 800 μm.

8. The method of claim 7, wherein: The thickness of the first stretched polymer layer is equal to the thickness of the second polymer layer.

9. The method of claim 1, wherein: The thickness of the thermoplastic elastomer layer is in the range of 25 μm to 75 μm.

10. The method of claim 1, wherein: The thermoformed curved laminate has a base curve greater than 5.0D.

11. The method of claim 1, wherein: The material of the thermoplastic elastomer layer is thermoplastic polyurethane or polyether block polyamide.

12. The method of claim 1, wherein: When heated above the stretching temperature, the diameter of the first stretched polymer layer narrows to be smaller than the diameter of the second polymer layer.

13. The method of claim 1, wherein: The polymer melt encapsulates the first stretched polymer layer and the thermoplastic elastomer layer on the second polymer layer.

14. An ophthalmic lens laminate comprising: a first stretched polymer layer having a thickness greater than 250 μm; a second polymer layer having a thickness greater than 250 μm; as well as A thermoplastic elastomer layer having a thickness in the range of 15 μm to 150 μm, the thermoplastic elastomer layer being disposed between the first stretched polymer layer and the second polymer layer, the thermoplastic elastomer layer being bonded to the first stretched polymer layer on the first side of the thermoplastic elastomer and to the second polymer layer on the second side of the thermoplastic elastomer layer.

15. The ophthalmic lens laminate of claim 14, wherein: The thickness of the first stretched polymer layer is equal to the thickness of the second polymer layer.

16. The ophthalmic lens laminate of claim 15, wherein: The thickness of the first stretched polymer layer and the thickness of the second polymer layer are each in a range of greater than 250 μm to 800 μm.

17. The ophthalmic lens laminate of claim 14, wherein: The first stretched polymer is a uniaxially stretched polycarbonate.

18. The ophthalmic lens laminate of claim 14, wherein: The first stretched polymer is a biaxially stretched polycarbonate.

19. The ophthalmic lens laminate of claim 14, wherein: The thickness of the thermoplastic elastomer layer is in the range of 25 μm to 75 μm.

20. The ophthalmic lens laminate of claim 14, wherein: The material of the thermoplastic elastomer layer is thermoplastic polyurethane or polyether block polyamide.

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