Method for producing thick laminated wafer for wafer thermoforming and injection molding
A three-layer laminate structure with specific thicknesses for polycarbonate and thermoplastic elastomer layers addresses defects in lens manufacturing by enhancing thermal insulation and mechanical rigidity, enabling efficient thermoforming and injection molding of high-base curve lenses.
Patent Information
- Application Number
- JP2025076145
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2020-02-26
- Filing Date
- 2025-05-01
- Publication Date
- 2025-07-25
AI Technical Summary
Existing methods for manufacturing lenses with functional films face defects due to temperature sensitivity, particularly when the glass transition temperature is approached, leading to issues during thermoforming and injection molding.
A method involving a three-layer laminate structure with a thermoplastic elastomer layer sandwiched between two polycarbonate layers, where the polycarbonate layers exceed 250 μm in thickness and the elastomer layer ranges from 15 μm to 150 μm, allowing for thermoforming and injection molding with reduced defects.
The method enables the production of lenses with improved structural integrity and reduced defects, such as buckling and haze, by controlling thermal insulation and mechanical rigidity, facilitating high-base curve formation without intermediate steps.
Smart Images
Figure 2025109735000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a thermoplastic elastomer-based optically functional film laminate, a film structure enabling thermoforming of a wafer to a high base curve, and suppression of haze and cooling flow lines during injection molding.
Background Art
[0002] The description of the background art herein is for the purpose of generally indicating the context of the present disclosure. The achievements of the present inventors named at the present time, the achievements within the scope described in the background art section, and the aspects of the description that may not be eligible as prior art at the time of filing are not admitted as prior art to the present disclosure, either explicitly or implicitly.
[0003] Functional optical films and / or laminates can be shaped (formed) and overmolded into lenses for dimming, polarizers or other functional applications. This includes methods of manufacturing a laminated structure, forming the laminate on a curved wafer, and injection molding to form a lens for health or light management.
[0004] Prescription or non-corrective eyewear lenses can be manufactured using injection molding of a polymer, such as polycarbonate or polyamide. This polymer injection molding method can be extended to overmolding of a thin multilayer laminated structure centered on a functional film of a given material that changes the overall functionality of the resulting lens. For example, a method of manufacturing a corrective or non-corrective polarizing sunglass lens can utilize a multilayer laminate including a layer impregnated with a dimming and / or polarizing dye as a central functional film.
Summary of the Invention
Problems to be Solved by the Invention
[0005] The physical properties of the central functional film can range from elastic to viscoelastic and can be crystalline to amorphous (and any intermediate portions) depending on the type of material and its physical and mechanical properties. However, in the case of a central functional film with a low glass transition temperature, as the operating temperature during manufacturing approaches the glass transition temperature of the central film, defects may occur in the resulting lens. Therefore, there is a need for a method of producing a thick laminated wafer through thermoforming and manufacturing a lens with fewer defects through injection molding.
Means for Solving the Problems
[0006] The present disclosure relates to a method of manufacturing an ophthalmic laminated lens, comprising the steps of forming a planar laminate by attaching a first polycarbonate layer to a first side of a thermoplastic elastomer layer and attaching a second polycarbonate layer to a second side of the thermoplastic elastomer layer, wherein the first polycarbonate layer has a thickness exceeding 250 μm, the second polycarbonate layer has a thickness exceeding 250 μm, and the thermoplastic elastomer layer has a thickness in the range of 15 μm to 150 μm; thermoforming the planar laminate into a curved laminate having a preformed curvature; placing the curved laminate in a mold; and molding the curved laminate into a curved lens using a polymer melt through a mold set at a predetermined temperature and a predetermined pressure.
[0007] The present disclosure additionally relates to an ophthalmic lens laminate comprising a first polycarbonate layer having a thickness exceeding 250 μm, a second polycarbonate layer having a thickness exceeding 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 polycarbonate layer and the second polycarbonate layer, and the thermoplastic elastomer layer being adhered to the first polycarbonate layer on a first side of the thermoplastic elastomer and adhered to the second polycarbonate layer on a second side of the thermoplastic elastomer.
[0008] It should be noted that this summary section does not specify any embodiments and / or progressively novel aspects of the present disclosure or the claims of the present invention. Rather, this summary merely presents prior discussions regarding different embodiments and corresponding novel points. For additional details and / or possible developments of the present invention and embodiments, reference may be made to the detailed description section of the present disclosure and the corresponding figures as described in more detail below.
[0009] Regarding various embodiments of the present disclosure proposed as multiple examples, the following figures in which similar elements are denoted by similar reference numerals will be referred to and described in detail.
Brief Description of the Drawings
[0010]
Figure 1A
Figure 1B
Figure 1C
Figure 1D
Figure 2A
Figure 2B
Figure 2C
Figure 2D
Figure 3A
Figure 3B
Figure 4
DETAILED DESCRIPTION OF THE INVENTION
[0011] The following disclosure provides many different embodiments or examples for implementing different features of the proposed subject matter. For the sake of clarity of the present disclosure, specific examples of elements and arrangements are described below. These are, of course, merely examples and are not intended to limit the present invention. For example, in the following description, forming the first feature to cover or overlay the second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features such that the first and second features cannot be in direct contact. Also, the present disclosure may repeat reference numerals and / or letters in various examples. This repetition is for the purpose of brevity and clarity and does not in itself refer to the relationship between the various embodiments and / or configurations being discussed. Further, spatially relative terms, such as "top", "bottom", "lower", "below", "under", "upper", "above", etc., may be used herein to facilitate the description of the relationship of one element or feature to another as illustrated. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. The device may be placed in different orientations (rotated 90 degrees or other orientations), and thus the spatially relative descriptors used herein can be interpreted similarly.
[0012] The order of discussion of the different steps described herein is presented for clarity purposes. Generally, these steps can be performed in any suitable order. Also, although each of the different features, techniques, configurations, etc. in this specification may be discussed at different places in the present disclosure, it is intended that each concept can be implemented independently of or in combination with each other. Accordingly, the present disclosure can be implemented and verified in many different ways.
[0013] A wafer can be cut from a planar laminated sheet into a circular or oval disk using a die-cutting tool. These planar laminated wafers are then thermoformed into a spherical dome shape. The diameter of the planar laminated wafer is determined by considering the desired lens diameter (e.g., 70 mm, 76 mm, 80 mm, etc.), the base curve of the thermoformed wafer (e.g., 0.25, 1.75, 3.00, 4.00, 4.50, 5.50, 6.00, 6.50, 7.25, 8.00 D, etc.), and the base curve of the mold insert (e.g., 1.75, 2.25, 3.25, 4.25, 5.50, 6.50, 7.50, 8.50 D, etc.). The base curve of the mold insert can be the same base curve as the convex refractive surface of the lens. If the wafer shrinks unevenly in one dimension more than in other dimensions, a nearly circular wafer can be obtained after thermoforming by using a flat, non-circular or oval wafer pattern. This forming process is generally performed by a vacuum-utilizing forming process in which the difficulty of converting a flat wafer into a high-quality thermoformed wafer increases with a high base (radius of curvature measured in diopters greater than 4.00 D).
[0014] Thermoplastic elastomers exhibit many beneficial properties when used as the main matrix in a functional center layer. The soft polymer segments exhibit flexibility and additive compatibility, while the harder segments exhibit torsional and flexural rigidity. However, thermoplastic elastomers (e.g., aliphatic thermoplastic polyurethanes, polyether block amide polyurethanes, etc.) are a class of polymers that can deform and flow under typical thermoforming and molding operations, resulting in overflow and bleed-out. Thermoplastic polyurethanes using polyether block polyamide segments are semi-crystalline polymers that can exhibit a hazy appearance (due to large spherulite growth) when gradually cooled from a viscous phase. Unlike functional films based on the polarity of hard polyvinyl alcohol (PVA), laminates formed from thermoplastic elastomers can have embossing or imprinting defects from contact with a hot defective surface (e.g., during insertion into a thermoformer or insertion into a concave or convex mold).
[0015] Furthermore, the thickness of many functional membranes or laminates ranges from 200 to 300 micrometers, and this thickness range is not sufficient to overcome all problems due to the physical and mechanical properties of the functional membrane, resulting in problems during thermoforming. Therefore, an improved laminate structure is needed to address the above problems.
[0016] The technology described herein provides a method and apparatus for manufacturing laminated lenses for glasses. The described embodiments can utilize a multilayer stack, such as a three-layer laminate formed by outer polymer layers provided on both sides of a central functional layer as part of the lens. As described above, the central functional layer can be affected by manufacturing conditions due to the temperature sensitivity of any material used in the central functional membrane. For example, the physical properties of the central functional membrane can range from elastic to viscoelastic, crystalline to amorphous (and any intermediate portions), and are affected by the operating temperature. The outer polymer membrane can be formed to provide improved thermal insulation to the central functional membrane. For example, changes in the thickness of one or both of the outer polymer membranes can accommodate the range of central functional membrane properties that occur during shaping the laminate from a planar wafer to a curved wafer (thermoforming, hydroforming, etc.), during injection molding, or both.
[0017] Figure 1A is a schematic view of a planar laminated wafer 100 according to an embodiment of the present disclosure. Figure 1A shows the diameters and base curves of various elements related to cutting, thermoforming, and molding. In one embodiment, the diameter d of the circular planar wafer fw is the same length as the arc length of the planar laminated wafer 100 after thermoforming.
[0018] Figure 1B is a schematic view of a thermoformed laminated wafer 105 according to an embodiment of the present disclosure. In one embodiment, the chord length d of the thermoformed laminated wafer 105 TF can be approximately the same diameter as the diameter of the lens.
[0019] Figure 1C is a schematic view of a concave mold insert 130 according to an embodiment of the present disclosure. In one embodiment, the diameter of the lens is, for example, the diameter d of the concave mold insert 130 Insertcan be determined accordingly. Thus, the chord length (d TF ) and the diameter of the concave mold insertion part 130 (d Insert ) can both be smaller than the diameter of the planar laminated wafer 100 (d fw ). The arc length of the concave mold insertion part 130 can be equal to or greater than the arc length of the thermoformed laminated wafer 105 due to the difference between the base curves of the planar laminated wafer 100 and the concave mold insertion part 130.
[0020] FIG. 1D is a schematic view of a molding apparatus according to an embodiment of the present disclosure. In one embodiment, the molding apparatus can include a first mold side surface 145a, a second mold side surface 145b, a concave mold insertion part 130, and a convex mold insertion part 135. The first mold side surface 145a and the second mold side surface 145b can each include a cavity portion, and the concave mold insertion part 130 and the convex mold insertion part 135 can be detachably disposed therein. As shown in FIG. 1D, the first mold side surface 145a including the concave mold insertion part 130 can be configured to be coupled with the second mold side surface 145b including the convex mold insertion part 135. When the concave mold insertion part 130 and the convex mold insertion part 135 are coupled, they can form a cavity connected to a hollow line formed by the coupling of the first and second mold side surfaces 145a, 145b. This line can be configured to receive a polymer via, for example, a screw feed or a similar device. The cavity can be configured to receive the thermoformed laminated wafer 105. The curved portions of the concave mold insertion part 130 and the convex mold insertion part 135 can determine the lens power of the resulting lens. For a semi-finished lens, the curved portion is fixed along the convex side of the lens, and the concave side of the lens can be corrected after molding, for example, via grinding and polishing. Note that since a plurality of lines for receiving the polymer can be connected, the injection of the polymer from the injection source can fill a plurality of molding apparatuses in a single injection, and a plurality of lenses can be manufactured in parallel.
[0021] Before placement into the forming device, the planar laminated wafer 100 can be thermoformed into the spherical dome shape of the thermoformed laminated wafer 105 via, for example, a thermoforming machine. During the execution of thermoforming, the planar laminated wafer 100 can be placed in a heated thermoforming insert, and a vacuum force can be applied to fix the planar laminated wafer 100 to the thermoforming insert. By adjusting the temperature of the applied heat and the applied vacuum force, the planar laminated wafer 100 can be formed into the curved shape of the thermoforming insert to manufacture the thermoformed laminated wafer 105.
[0022] In one embodiment, the planar laminated wafer 100 can include a first layer 115, a center layer 120, and a second layer 125. As shown in FIG. 1D, by thermoforming the planar laminated wafer 100, a curved structure can be manufactured in which the first layer 115 is on the concave side and the second layer 125 is on the convex side.
[0023] In one embodiment, the thermoformed laminated wafer 105 can be placed within the forming device adjacent to the female mold insert 130, and the convex side surface of the thermoformed laminated wafer 105 (i.e., the second layer 125) is adjacent to the female mold insert 130. The thermoformed laminated wafer 105 abuts against the female mold insert 130, and the edge of the thermoformed laminated wafer 105 protrudes (dTF = d Insert ) to fix the thermoformed laminated wafer 105 within the mold cavity. If the base curve of the thermoformed laminated wafer 105 is smaller than the base curve of the female mold insert 130, a planar laminated wafer 100 with a smaller diameter can be used to maintain a constant chord length (or lens diameter), i.e., the chord length of the base curve of all thermoformed laminated wafers 105 is preferably equal to the diameter of the female mold insert 130, to prevent the thermoformed laminated wafer 105 from falling out of the cavity during the loading operation. This is relevant particularly when using a vacuum and there is a need to seal between the thermoformed laminated wafer 105 and the female mold insert 130.
[0024] The outer perimeter of the planar laminated wafer 100 is d greater than the outer perimeter of the thermoformed laminated wafer 105 fw / d TFIt should also be noted that it can only increase by the ratio of. When exceeding a predetermined ratio, edge deformation occurs, and the extra length at the edge of the planar laminated wafer 100 can be accommodated by compression, out-of-plane deformation, buckling, or wrinkle formation at the edge of the thermoformed laminated wafer 105.
[0025] The planar laminated wafer 100 can be thermoformed into a medium (4.00D) to high (8.50D) base curve, and the diameter d of the planar laminated wafer 100 fw is much larger than the diameter d of the thermoformed laminated wafer 105 TF . The ability to apply tension and compression to the laminated structure (e.g., the planar laminated wafer 100) without failure is substantially based on the mechanical properties of the composition of the laminate. Mechanical properties such as torsional rigidity, ductility, and elasticity play an important role in the thermoforming of the planar laminated wafer 100. Using a softer and more ductile material (over 50 microns) for the central layer 120 increases the likelihood of defects. Commonly seen wafer defects include buckling and wrinkle formation at any arrangement or centering tab. Adjusting the layer thickness to increase the torsional rigidity of the planar laminated wafer 100 is described herein. It will be understood that the planar laminated wafer 100 can be thermoformed using known apparatuses and methods, such as LEMA of Italy machine, to gradually increase the curvature of the planar laminated wafer 100 while heat is applied.
[0026] Figure 2A is a schematic view of the layers of a planar laminated wafer 100 according to an embodiment of the present disclosure. It will be understood that the planar laminated wafer 100 can be manufactured using techniques known to those skilled in the art. In one example, an adhesive laminate can be used, where a first layer 115 and a second layer 125 are bonded to a central layer 120 using an adhesive and brought close to each other by a pair of nip rollers. The nip rollers can be configured to facilitate spreading of the adhesive while controlling the thickness of the planar laminated wafer 100 and squeezing the layers against each other. In another example where a high-temperature molten central layer 120 is sandwiched between the first layer 115 and the second layer 125, an extrusion laminate can be used. The thickness in this example can be adjusted through the gap setting of the nip rollers. In another example, an adhesive coating laminate can be used, and the central layer 120 can be solution-cast and dried on a carrier film. In this state, since the central layer 120 is more adhesive and sticky, it can be transferred from the carrier film to the first layer 115 and the second layer 125 using a pair of nip rollers configured to pressure-seal the layers. Thus, as described above, in some examples, an optional adhesive can be applied between the central layer 120 and the outer first and second layers 115, 125. In a plurality of other examples, the layers can be directly adhered to each other.
[0027] The central layer 120 can be an optically functional thermoplastic elastomeric resin. In one example, the central layer 120 can be thermoplastic polyurethane (TPU). In another example, the central layer 120 can be semi-crystalline polyether block polyamide (PEBA). In particular, optical additives (e.g., dimming dyes, color tone dyes, dye absorbers of selected wavelengths, electrochromic dyes, etc.) can be mixed with the central layer 120 to produce an optically functional film. The first layer 115 and the second layer 125 can be, for example, polycarbonate, cellulose ester (e.g., cellulose triacetate), acrylic, cyclic olefin copolymer, etc., and are optically transparent with little or no haze.
[0028] Figure 2B is a schematic view of the layers of the planar laminated wafer 100 with an asymmetric thickness according to an embodiment of the present disclosure. In one embodiment, the planar laminated wafer 100 may include a first layer 115, a central layer 120, and a second layer 125. The first layer 115 is configured to thermally insulate the central layer 120 and provide additional structural rigidity during thermoforming. The thicknesses of the first layer 115 and the second layer 125 are different. For example, the thickness of the second layer 125 may be about 250 micrometers (μm). To thermally insulate the central layer 120 and provide additional structural rigidity during thermoforming, the thickness of the first layer 115 may exceed 250 μm. For example, the thickness of the first layer 115 may be in the range of 350 - 800 μm. The thickness of the central layer 120 may be, for example, in the range of 15 - 150 μm. This structure can be used in Figure 3A. The thicker first layer 115 can also reduce defects in the form of buckling, deformation, or wrinkles when thermoforming to a high base curve, for example, a base curve of 4.00D or more. In particular, the thermoformed laminated wafer 105 having a thick first layer 115 can be directly formed to a high base curve (e.g., 8.00D) in one pass, skipping intermediate steps. That is, it can be directly formed from the planar laminated wafer 100 to an 8.00D base curve without performing any forming to an intermediate base curve.
[0029] In an alternative embodiment, the second layer 125 is thicker than the first layer 115. For example, the thickness of the first layer 115 may be about 250 μm, and the thickness of the second layer 125 may exceed 250 μm. Thus, when placed within the forming device, the thicker layer (the second layer 125) is adjacent to the recessed mold insert 130.
[0030] FIG. 2C is a schematic diagram of the layers within a planar laminated wafer 100 having a symmetric thickness according to an embodiment of the present disclosure. In one embodiment, the planar laminated wafer 100 may include a first layer 115, a central layer 120, and a second layer 125. The first layer 115 is configured to thermally insulate the central layer 120 during thermoforming to provide additional structural rigidity. The thicknesses of the first layer 115 and the second layer 125 are the same. To thermally insulate the central layer 120 and provide additional structural rigidity during thermoforming, the thickness of the first layer 115 may exceed 250 μm. For example, the thickness of the first layer 115 may be in the range of 350 - 800 μm. The thickness of the second layer 125 may be the same as that of the first layer 115. The thickness of the central layer 120 may be in the range of, for example, 15 - 150 μm.
[0031] FIG. 2D is a schematic diagram of the layers within a planar laminated wafer 100 having an asymmetric thickness and a varying diameter according to an embodiment of the present disclosure. In one embodiment, the planar laminated wafer 100 may include a first layer 115, a central layer 120, and a second layer 125. The first layer 115 and the central layer 120 have the same diameter that is smaller than the diameter of the second layer 125, and the second layer 125 is thicker than the first layer 115. To provide additional structural rigidity during thermoforming, the thickness of the second layer 125 may exceed 250 μm. For example, the thickness of the second layer 125 may be in the range of 350 - 800 μm. The thickness of the first layer 115 may be about 250 micrometers (μm). The thickness of the central layer 120 may be in the range of, for example, 15 - 150 μm. This structure can be used in FIG. 3B. In particular, one advantage of using an asymmetric thickness design is that it reduces the overall thickness of the laminate so that the planar laminated wafer 100 is not too thick to be formed. Also, since the diameters of the first layer 115 and the central layer 120 are smaller than that of the second layer 125, the planar laminated wafer 100 can be thermoformed such that defects along the edge of the wafer, delamination between layers, and buckling on the concave side are reduced. Furthermore, in an asymmetric thickness design, the overall thickness does not increase significantly, making it suitable for injection molding.
[0032] In an alternative embodiment, the thickness of the first layer 115 is the same as that of the second layer 125. For example, the thickness of the first layer 115 can be in the range of 350 to 800 μm. In this embodiment, the additional advantage of structural rigidity is achieved by one of the first layer 115 or the second layer 125 being thick.
[0033] FIG. 3A is a schematic view of a laminated wafer 105 thermoformed with an asymmetric layer thickness in a forming apparatus according to an embodiment of the present disclosure. In one embodiment, the thermoformed laminated wafer 105 is disposed in the cavity such that the thicker first layer 115 is adjacent to the location where the polymer melt 140 is injected into the cavity. Starting from the empty forming apparatus, the thermoformed laminated wafer 105 is disposed adjacent to the concave mold insert 130. The first mold side 145a that houses the concave mold insert 130 is brought closer to the second mold side 145b that houses the convex mold insert 135 so as to be joined. This can be performed, for example, by a hydraulic or electric press that presses one of the mold sides 145a, 145b against the other to close. After joining the mold sides 145a, 145b, the polymer melt 140 (e.g., molten polycarbonate) is injected into the cavity of the forming apparatus between the thermoformed laminated wafer 105 and the convex mold insert 135. In some implementations, the polymer melt 140 includes a transparent or translucent thermoplastic material such as polycarbonate, thermoplastic urethane, 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 or derivatives or mixtures thereof.
[0034] The polymer melt 140 gradually cools inside the mold over time, adheres to the thermoformed laminate wafer 105, and can be discharged from the molding apparatus when the mold sides 145a and 145b are separated. The mold sides 145a, 145b can be thermally controlled independently. The concave and convex mold inserts 130, 135 can also be thermally controlled independently or can depend on the mold sides 145a, 145b for heat dissipation. That is, the concave and convex mold inserts 130, 135 can be thermally coupled to the mold sides 145a, 145b, and the mold sides 145a, 145b can be made large enough for the heat sink to absorb the heat conducted from the polymer melt 140 to the concave and convex mold inserts 130, 135 during cooling. In particular, increasing the thickness of the first layer 115 or the second layer 125 leads to reducing the defects of the lens after injection molding in order to provide sufficient structural integrity to prevent buckling of the outer edge of the thermoformed laminate wafer 105 during thermoforming.
[0035] In one embodiment, the central layer 120 is a polyether block amide (PEBA). Injection molding of PEBA causes manufacturing difficulties due to the morphological properties of the PEBA polymer, which are mainly based on intermolecular order and crystallinity, both of which are affected by the temperature rise during manufacturing. When the thermoformed laminated wafer 105 having the PEBA central layer 120 is injection molded by the polymer melt 140, the resulting semi-finished lens may contain distinct and repetitive defects known as "haze" across the center or the entire lens. This haze may be the result of slow cooling following heating of the PEBA central layer 120 due to heat transfer from the polymer melt 140 across the first layer 115 to the central layer 120. Importantly, when the first and second layers 115, 125 are thin, the amount of heat conducted to the PEBA central layer 120 increases, melting the crystalline regions within the central layer 120. Further, since both the first and second layers 115, 125 are thin, the cooling of the PEBA central layer 120 follows the slower cooling rate of the polymer melt 140. This slow cooling rate allows the crystalline regions of the PEBA central layer 120 to grow, resulting in scattered light and haze in the final lens. Therefore, due to the asymmetric design of the thermoformed laminated wafer 105 having a thicker first layer 115 adjacent to the polymer melt 140, the temperature of the PEBA central layer 120 is closer to the temperature of the concave mold insert 130. This means that due to the thicker first layer 115, the PEBA central layer 120 is thermally insulated from the heat of the polymer melt 140, resulting in a faster cooling rate. A faster cooling rate inhibits the growth of large crystalline regions within the PEBA central layer 120, reducing scattered light in the final lens. Therefore, the thickness of the first layer 115 can be determined based on the temperature of the injected polymer melt 140 such that it prevents heat transfer from the polymer melt 140 to the central layer 120 exceeding a predetermined threshold, where the predetermined threshold is determined by the cooling rate of the central layer 120 such that the growth of crystalline regions within the central layer 120 is inhibited or completely prevented.
[0036] Figure 3B is a schematic view of a laminated wafer 105 thermoformed to different layer diameters within a forming apparatus, according to one embodiment of the present disclosure. In one embodiment, the diameters of the first layer 115 and the center layer 120 may be smaller than the second layer 125 such that the thermoformed laminated wafer 105 can be thermoformed extremely well up to a high base curve (greater than 4.0D base) without wrinkles at the edges. Another advantage of using an asymmetric design for thickness and diameter is that the injection molding process can be performed better to avoid contamination of the concave and convex mold inserts 130, 135. Similarly, the thermoformed laminated wafer 105 is disposed in the cavity such that the first layer 115 is adjacent to the location where the polymer melt 140 is injected into the cavity. Then, the injection molding process described with respect to FIG. 3A can be performed.
[0037] FIG. 4 is a flowchart of a method for manufacturing a spectacle lens according to an embodiment of the present disclosure. In step S401, a planar laminated wafer 100 is formed. For example, the planar laminated wafer 100 can be formed by an adhesive lamination, an extrusion lamination, an adhesive coating lamination, or any other known method. The planar laminated wafer 100 can include, for example, three layers in which the central layer 120 is a thermoplastic elastomer. In step S403, the planar laminated wafer 100 is formed into a thermoformed laminated wafer 105. Using a thermoforming apparatus, the curvature and shape of the planar laminated wafer 100 can be corrected before forming within the forming apparatus. In step S405, the thermoformed laminated wafer 105 is disposed within the forming apparatus. For example, the thermoformed laminated wafer 105 is disposed adjacent to a concave mold insertion portion 130 such that the convex side surface of the thermoformed laminated wafer 105 faces the concave mold insertion portion 130. The concave mold insertion portion 130 can fix the thermoformed laminated wafer 105 by a vacuum force. Mold side surfaces 145a and 145b can be pressed against each other and joined to form a seal. In step S407, the polymer melt 140 can be injected into the cavity of the mold apparatus between the thermoformed laminated wafer 105 and the convex mold insertion portion 135. In step S409, the lens is formed by cooling the polymer melt 140 within the mold apparatus. The heat and pressure from the polymer melt 140 can additionally heat the thermoformed laminated wafer 105 to press the thermoformed laminated wafer 105 against the curvature of the concave mold insertion portion 130 for further forming. It will be understood that the present method can be used to form "flat" spectacle lenses, plano spectacle lenses, prescription spectacle lenses, and "high wrap" sunglasses and goggles.
[0038] In the above description, the specific geometry of the processing system, various elements, and specific details of the processing and the like used therein have been disclosed. However, it will be understood that the techniques described in this specification can be implemented in other embodiments different from these specific details, and such details are for illustrative purposes and not for limiting purposes. The embodiments disclosed in this specification have been described with reference to the accompanying drawings. Similarly, specific numbers, materials, and configurations have been disclosed for illustrative purposes to provide a detailed understanding. Nevertheless, the embodiments can be implemented without such specific details. Components having substantially the same functional structure are denoted by the same reference numerals, and thus, all redundant descriptions can be omitted.
[0039] To assist in the understanding of various embodiments, various techniques have been described as a plurality of separate operations. The order of the description should not be construed as suggesting that these operations are necessarily order-dependent. In fact, these operations need not be executed in the presented order. The operations described can be executed in an order different from the described embodiments. Various additional operations can be performed and / or operations described in additional embodiments can be omitted.
[0040] Those skilled in the art will also understand that many modifications can be made to the operations of the above-described techniques while still achieving the same objectives of the present invention. Such modifications are intended to be included within the scope of this disclosure. Thus, the above description of the embodiments of the present invention is not intended to be limiting. Rather, any limitations on the embodiments of the present invention are set forth in the following claims.
[0041] The embodiments of the present disclosure can also be as indicated by the numbers in the following parentheses.
[0042] (1) A method of forming a laminated lens for glasses, comprising the steps of forming a planar laminate by attaching a first polycarbonate layer to a first side of a thermoplastic elastomer layer and attaching a second polycarbonate layer to a second side of the thermoplastic elastomer layer, wherein the first polycarbonate layer has a thickness exceeding 250 μm, the second polycarbonate layer has a thickness exceeding 250 μm, and the thermoplastic elastomer layer has a thickness in the range of 15 μm to 150 μm; thermoforming the planar laminate into a curved laminate having a preformed curvature; placing the curved laminate in a mold; and molding the curved laminate into a curved lens using a polymer melt through a mold set at a predetermined temperature and a predetermined pressure.
[0043] (2) The mold includes a concave mold insert and a convex mold insert, the curved laminate is placed in the mold such that the second polycarbonate layer is adjacent to the concave mold insert, and the polymer melt is injected between the first polycarbonate layer of the curved laminate and the convex mold insert in the method of (1).
[0044] (3) The thickness of the first polycarbonate layer is equal to the thickness of the second polycarbonate layer, and the first polycarbonate layer in contact with the polymer melt generates the concave surface of the curved lens in either method of (1) or (2).
[0045] (4) The first thickness of the first polycarbonate layer and the second thickness of the second polycarbonate layer are each in the range of 380 μm to 800 μm in any one of the methods of (1) to (3).
[0046] (5) The thickness of the first polycarbonate layer exceeds the thickness of the second polycarbonate layer, and the first polycarbonate layer in contact with the polymer melt generates the concave surface of the curved lens in either method of (1) or (2).
[0047] (6) The thickness of the first polycarbonate layer is in the range of 380 μm to 800 μm in any one of the methods of (1), (2), (4) or (5).
[0048] (7) The diameter of the first polycarbonate layer and the diameter of the thermoplastic elastomer layer are both smaller than the diameter of the second polycarbonate layer, by any one of the methods (1) to (6).
[0049] (8) The thickness of the second polycarbonate layer exceeds the thickness of the first polycarbonate layer, and the first polycarbonate layer in contact with the polymer melt forms the concave surface of the curved lens, by any one of the methods (1) to (7).
[0050] (9) The step of thermoforming the flat laminate into a curved laminate is performed without any intermediate forming steps, by any one of the methods (1) to (8).
[0051] (10) The thermoformed curved laminate has a base curve greater than 5.0D, by any one of the methods (1) to (9).
[0052] (11) The material of the thermoplastic elastomer layer is thermoplastic polyurethane, by any one of the methods (1) to (10).
[0053] (12) The material of the thermoplastic elastomer layer is polyether block polyamide, by any one of the methods (1) to (11).
[0054] (13) The thickness of the first polycarbonate layer is determined based on the temperature of the injected polymer melt so as to prevent heat transfer exceeding a predetermined threshold from the polymer melt to the thermoplastic elastomer layer, by any one of the methods (1) to (12).
[0055] (14) An ophthalmic lens laminate, comprising: a first polycarbonate layer having a thickness exceeding 250 μm; a second polycarbonate layer having a thickness exceeding 250 μm; and a thermoplastic elastomer layer having a thickness of 15 μm to 150 μm, disposed between the first polycarbonate layer and the second polycarbonate layer, bonded to the first polycarbonate layer on the first side of the thermoplastic elastomer, and bonded to the second polycarbonate layer on the second side of the thermoplastic elastomer layer.
[0056] (15) The ophthalmic lens laminate according to (14), wherein the thickness of the first polycarbonate layer is equal to the thickness of the second polycarbonate layer.
[0057] (16) The ophthalmic lens laminate according to either (14) or (15), wherein the thickness of the first polycarbonate layer and the thickness of the second polycarbonate layer are each in the range of more than 250 μm to 800 μm.
[0058] (17) The ophthalmic lens laminate according to any one of (14) to (16), wherein the thickness of the first polycarbonate layer and the thickness of the second polycarbonate layer are each in the range of 360 μm to 600 μm.
[0059] (18) The ophthalmic lens laminate according to (14), wherein the thickness of the first polycarbonate layer exceeds the thickness of the second polycarbonate layer.
[0060] (19) The ophthalmic lens laminate according to either (14) or (18), wherein the thickness of the first polycarbonate layer and the thickness of the second polycarbonate layer are each in the range of 250 μm to 800 μm.
[0061] (20) The ophthalmic lens laminate according to any one of (14), (18) or (19), wherein the thickness of the first polycarbonate layer is in the range of 360 μm to 800 μm, preferably in the range of 360 μm to 600 μm, and the thickness of the second polycarbonate layer is in the range of 250 μm to 550 μm, for example in the range of 450 μm to 550 μm, more preferably in the range of 250 μm to 350 μm.
[0062] (21) The thickness of the first polycarbonate layer is in the range of 360 μm to 600 μm, and the thickness of the second polycarbonate layer is in the range of 250 μm to 350 μm, for the spectacle lens laminate of (20).
Claims
1. A method of forming a laminated lens for glasses, comprising: forming a planar laminate by attaching a first polycarbonate layer to a first side of a thermoplastic elastomer layer and attaching a second polycarbonate layer to a second side of the thermoplastic elastomer layer, wherein the first polycarbonate layer has a thickness greater than 250 μm, the second polycarbonate layer has a thickness greater than 250 μm, and the thermoplastic elastomer layer has a thickness in the range of 15 μm to 150 μm; thermoforming the planar laminate into a curved laminate having a preformed curvature; placing the curved laminate in a mold; and molding the curved laminate into a curved lens using a polymer melt through the mold set at a predetermined temperature and a predetermined pressure. A method comprising the above steps.
2. The mold includes a concave mold insert and a convex mold insert, the curved laminate is placed in the mold such that the second polycarbonate layer is adjacent to the concave mold insert, and the polymer melt is injected between the first polycarbonate layer of the curved laminate and the convex mold insert. The method according to claim 1.
3. The thickness of the first polycarbonate layer is equal to the thickness of the second polycarbonate layer, and the first polycarbonate layer in contact with the polymer melt forms the concave surface of the curved lens. The method according to claim 2.
4. The first thickness of the first polycarbonate layer and the second thickness of the second polycarbonate layer are each in the range of 380 μm to 800 μm. The method according to claim 3.
5. The thickness of the first polycarbonate layer is greater than the thickness of the second polycarbonate layer, and the first polycarbonate layer in contact with the polymer melt forms the concave surface of the curved lens. The method according to claim 2.
6. The thickness of the first polycarbonate layer is in the range of 380 μm to 800 μm, and the second thickness of the second polycarbonate layer is in the range of 250 μm to 600 μm. The method according to claim 5.
7. Both the diameter of the first polycarbonate layer and the diameter of the thermoplastic elastomer layer are smaller than the diameter of the second polycarbonate layer. The method according to claim 2.
8. The thickness of the second polycarbonate layer exceeds the thickness of the first polycarbonate layer, and The method according to claim 7, wherein the first polycarbonate layer in contact with the polymer melt forms the concave surface of the curved lens. **Claim 9** The method according to claim 2, wherein the step of thermoforming the planar laminate into the curved laminate is performed without any intermediate forming steps. **Claim 10** The method according to claim 9, wherein the thermoformed curved laminate has a base curve greater than 5.0 D. **Claim 11** The method according to claim 2, wherein the material of the thermoplastic elastomer layer is thermoplastic polyurethane. **Claim 12** The method according to claim 2, wherein the material of the thermoplastic elastomer layer is polyether block polyamide. **Claim 13** The thickness of the first polycarbonate layer is determined based on the temperature of the injected polymer melt so as to prevent heat transfer exceeding a predetermined threshold from the polymer melt to the thermoplastic elastomer layer. The method according to claim 12. **Claim 14** An ophthalmic lens laminate, A first polycarbonate layer having a thickness greater than 250 μm, A second polycarbonate layer having a thickness greater than 250 μm, A thermoplastic elastomer layer having a thickness in the range of 15 μm to 150 μm, disposed between the first polycarbonate layer and the second polycarbonate layer, bonded to the first polycarbonate layer on a first side of the thermoplastic elastomer, and bonded to the second polycarbonate layer on a second side of the thermoplastic elastomer, a thermoplastic elastomer layer An ophthalmic lens laminate comprising. **Claim 15** The ophthalmic lens laminate according to claim 14, wherein the thickness of the first polycarbonate layer is equal to the thickness of the second polycarbonate layer. **Claim 16** The ophthalmic lens laminate according to claim 15, wherein the thickness of the first polycarbonate layer and the thickness of the second polycarbonate are each in the range of more than 250 μm to 800 μm. **Claim 17** The ophthalmic lens laminate according to claim 16, wherein the thickness of the first polycarbonate layer and the thickness of the second polycarbonate layer are each in the range of 360 μm to 600 μm. **Claim 18** The spectacle lens laminate according to claim 14, wherein the thickness of the first polycarbonate layer exceeds the thickness of the second polycarbonate layer.
19. The spectacle lens laminate according to claim 18, wherein the thickness of the first polycarbonate layer and the thickness of the second polycarbonate layer are each in the range of 250 μm to 800 μm.
20. The thickness of the first polycarbonate layer is in the range of 360 μm to 600 μm, and The spectacle lens laminate according to claim 19, wherein the thickness of the second polycarbonate layer is in the range of 250 μm to 550 μm.