Patent Publication Number: US-2023148025-A1

Title: Optical microstructure-containing laminate for ophthalmic lens incorporation

Description:
BACKGROUND 
     Field of the Disclosure 
     The present disclosure relates to a laminate, comprising optical microstructures that allow for universal application to ophthalmic lenses for correction of aberrant vision. 
     Description of the Related Art 
     Myopia, also known as near-sightedness and short-sightedness, is a condition of the eye where the light that enters the eye is not focused directly on the retina. Instead, the light that enters the eye is focused in front of the retina, causing the image that the individual observes to be in or out of focus depending on a distance of an object from the eye of the individual. For instance, when an object is a distant object, the observed object will be out of focus while, when the object is a near object, the observed object will be in focus. 
     Though correctable by refractive surgery, myopia is most commonly corrected through the use of corrective lenses, such as glasses or contact lenses. The corrective lenses have a negative optical power (i.e., have a net concave effect), which compensates for the excessive positive diopters of the myopic eye. Negative diopters are generally used to describe a severity of a myopic condition, as this is the value of the lens to correct the vision. 
     Recently, efforts in addressing the progression of myopia in children and young adults have included providing optical microstructures directly on surfaces of corrective lenses. The optical microstructures may be microlenses, for instance, that redirect part of the incoming light to the retina. The use of microlenses on the surface of a regular single vision lens to introduce peripheral defocus has been shown to be very effective in slowing the progression of myopia. 
     To now, however, optical microstructures have been incorporated directly on surfaces of the corrective lenses. The optical microstructures may be engraved, etched, or embossed directly on either a convex surface of the corrective lens (e.g. a lens surface opposite to a lens surface adjacent to an eye of a wearer) or a concave surface of the corrective lens (e.g. a lens surface adjacent to an eye of a wearer). In one instance, this arrangement may lead to scratching or other damage to the optical microstructures as a result of everyday use. Moreover, by creating the optical microstructures directly on a lens surface of the corrective lenses, a unique design may be needed for each lens substrate material as each optical microstructure design is dependent on a change in refractive index between the optical microstructure and a surrounding medium, every lens substrate material requiring a unique set of optical designs. In this way, each lens substrate material may require a unique optical microstructure architecture and arrangement. It can be appreciated that such an approach becomes impracticable at scale and demands a more generally-applicable solution. 
     According to an embodiment, the present disclosure provides a solution that allows a limited number of optical microstructure designs to be used with any given material and on a variety of lens substrate materials. 
     The foregoing “Background” description is for the purpose of generally presenting the context of the disclosure. Work of the inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present disclosure. 
     SUMMARY 
     According to the claims, the present disclosure relates to a laminate and a method of generating a laminate for prevention of myopia progression. 
     According to an embodiment, the present disclosure further relates to a laminate, comprising a first film, of a first material having a first refractive index, including a pattern of microstructures embossed on a first surface of the first film, each microstructure of the embossed pattern of microstructures being an optical microstructure arranged at a predetermined distance between adjacent optical microstructures, and a second film, of a second material having a second refractive index, including structures arranged on a first surface of the second film at positions corresponding to areas of the first surface of the first film defined by the predetermined distance between adjacent optical microstructures, wherein when the second film is laminated to the first film, the structures arranged on the first surface of the second film are in contact with the areas of the first surface of the first film defined by the predetermined distance between adjacent optical microstructures, a height of the structures of the second film is greater than a height of each optical microstructure, and a delta between the height of the structures of the second film and the height of each optical microstructure encapsulates, upon the lamination of the second film to the first film, a void fill material within at least a portion of at least one void defined by the delta, the void fill material having a predetermined refractive index. 
     The foregoing paragraphs have been provided by way of general introduction, and are not intended to limit the scope of the following claims. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG.  1    is an illustration of a lens having optical microstructures directly on a surface thereof; 
         FIG.  2    is an illustration of a laminate including optical microstructures, according to an exemplary embodiment of the present disclosure; 
         FIG.  3 A  is an illustration of a laminate including optical microstructures, according to an exemplary embodiment of the present disclosure; 
         FIG.  3 B  is a flow diagram of a method of preparing a laminate including optical microstructures, according to an exemplary embodiment of the present disclosure; 
         FIG.  4 A  is an illustration of a first film of a laminate including optical microstructures, according to an exemplary embodiment of the present disclosure; 
         FIG.  4 B  is an illustration of a second film of a laminate including optical microstructures, according to an exemplary embodiment of the present disclosure; 
         FIG.  5    is an illustration of a first film of a laminate including optical microstructures, according to an exemplary embodiment of the present disclosure; 
         FIG.  6 A  is an illustration of a lens having a laminate including optical microstructures laminated thereto, according to an exemplary embodiment of the present disclosure; 
         FIG.  6 B  is an illustration of a lens having a laminate including optical microstructures laminated thereto, according to an exemplary embodiment of the present disclosure; 
         FIG.  7 A  is an illustration of a lens having a laminate including optical microstructures laminated thereto via adhesive, according to an exemplary embodiment of the present disclosure; and 
         FIG.  7 B  is an illustration of a lens having a laminate including optical microstructures laminated thereto via adhesive, according to an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The terms “a” or “an”, as used herein, are defined as one or more than one. The term “plurality”, as used herein, is defined as two or more than two. The term “another”, as used herein, is defined as at least a second or more. The terms “including” and/or “having”, as used herein, are defined as comprising (i.e., open language). Reference throughout this document to “one embodiment”, “certain embodiments”, “an embodiment”, “an implementation”, “an example” or similar terms means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of such phrases or in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments without limitation. 
     The terms “wafer” and “laminate” may be used interchangeably to refer to a similar structure. 
     The terms “about” and “approximately” are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment the terms are defined to be within 10%, preferably, within 5%, more preferably, within 1%, and most preferably, within 0.5%. 
     According to an embodiment, the present disclosure provides a solution that allows a limited number of optical microstructure designs to be used with any given material and on a variety of lens substrate materials. In effect, the present disclosure describes a laminate containing optical microstructures that may be broadly applicable via lamination to a given corrective lens. 
     In particular, the present invention pertains to a method to incorporate plano, flat, or curved wafers comprising laminated films that contain optical microstructures (e.g. microscale features) into the bulk or onto the surface of an optical lens (e.g., plano or powered) that is devoid of optical microstructures. In this way, the intensive design and fabrication process associated with generating unique architectures and arrangements for different lens substrate materials can be avoided in favor or more generally applicable approach. 
     In an embodiment, the curved wafer, or laminate, can be a single design and material that can be used with several optical lens substrate materials. As introduced above, this approach circumvents the need for using different optical microstructure designs with different optical lens substrate materials. 
     In an embodiment, the optical microstructure design may be a protrusion from a surface of a film of the wafer. The optical microstructure design may be a microlens, for instance, and may have an appearance of concentric circles or other organized arrangement of patterns on the lens surface. The design of the microlens array that provides the concentric circles or other surface pattern appearance may be fixed relative to other components of the wafer. For instance, the design of the microlens may be fixed with consideration to the difference between a refractive index of the microlens material and a refractive index of a neighboring medium (e.g., a coating, an adhesive, a conformational film, etc.). 
     Turning now to the Figures, the above-introduced design of each optical microstructure of an array of optical microstructures allows for application of a wafer, or a laminate, of the present disclosure to a variety of optical lens substrates. This approach is an improvement over present technology, described in  FIG.  1   , wherein an optical lens  101  may be directly modified through engraving, etching, embossing, coating, or other approach to provide optical microstructures  105  directly on a surface of the optical lens  101 . As described, direct modification of a surface of the optical lens  101  may lead to poor visual acuity as a result of, for instance, scratching of the optical microstructures  105  disposed thereon. Accordingly, the present disclosure describes a laminate, introduced in  FIG.  2   , allowing for wide use of a single architecture and arrangement of optical microstructures to accommodate a variety of optical lens substrates. 
     With reference to  FIG.  2   , a cross-sectional schematic of a laminate  210  before lamination, a first film  211  and a second film  212  of the laminate  210  are provided. The first film  211  may be a first material having a first refractive index. In an example, the first film  211  may be, as the first material, cellulose triacetate (TAC), poly(methyl methacrylate) (PMMA), or polycarbonate (PC), wherein the first material has a refractive index of approximately 1.48, 1.5, or 1.59 for the material thereof. The first film  211  may include, disposed on a first surface  216  of the first film  211 , one or more optical microstructures  205 . Each of the one or more optical microstructures  205  may have a dimensional height  207 , a dimensional width  260 , and may be separated from an adjacent one of the one or more optical microstructures  205  by a predetermined distance  206  that defines an area between the one or more optical microstructures  205 . Presented as having a hemispherical shape in  FIG.  2   , each of the one or more optical microstructures  205  may have a variety of shapes including hemispherical, rectangular, cylindrical, pyramidal, circular, elliptical, triangular, and prismatic, among others, as demanded by a visual requirement. It can be appreciated that the first film  211 , having on the first surface  216  thereof the one or more optical microstructures  205 , provides the concentric circles or other surface pattern appearance. The second film  212  of the laminate  210  may be a second material having a second refractive index. In an example, the second material of the second film  212  may have the same, lower, or higher refractive index. Accordingly, the second refractive index may be, for instance, 1.4, 1.5 or 1.74. It can be appreciated that the use of the phrases “lower refractive index” and “higher refractive index” reflect relative terms between the first material of the first film  211  and the second material of the second film  212 . The second film  212  may include, disposed on a first surface  217  of the second film  212 , one or more structures  214 . The one or more structures  214  may have a dimensional height  215  and may be separated by a distance such that a contacting surface  218  is aligned with a corresponding area of the first film  211  defined by the predetermined distance  206  between adjacent ones of the one or more optical microstructures  205 . Presented as having a rectangular shape in  FIG.  2   , each of the one or more structures  214  may have a variety of shapes including hemispherical, rectangular, cylindrical, pyramidal, circular, elliptical, prismatic, and triangular, among others, as dictated by the shape of the area defined by the predetermined distance  206  between adjacent ones of the one or more optical microstructures  205 . 
     According to an embodiment, each of the one or more optical microstructures  205  may have a higher refractive index than a medium surrounding it. In other words, a difference in refractive indices may be positive. 
     According to an embodiment, the one or more optical microstructures  205  may be hemispherical and the dimensional width  260  may be a diameter. Given a fixed diameter, and assuming a difference between refractive indices of the one or more optical microstructures  205   and a surrounding medium is large (i.e., Δ = 0.7), the dimensional height  207  of the one or more optical microstructures  205  may be small. If, however, given a fixed diameter and assuming a difference between refractive indices of the one or more optical microstructures  205  and a surrounding medium is small (i.e., Δ = 0.2), the dimensional height  207  of the one or more optical microstructures  205  may be large. 
     In an example, if the difference between refractive indices of the one or more optical microstructures  205  and a surrounding medium is negative, concavity of the one or more optical microstructures  205  must change (e.g. be inverted) to ensure the same power result. In an embodiment, the curvature design depends on the desired target functionality of the one or more optical microstructures  205 . If the desired target functionality is prevention of myopia progression, a positive difference in refractive indices is preferred. It can be appreciated that, given a surrounding medium refractive index of 1.0, a refractive index of the one or more optical microstructures  205  may be 1.74, thereby producing a minimal dimensional height  207 . 
     In an embodiment, with reference to  FIG.  3 A  and  FIG.  3 B , a laminate  310  similar to that of  FIG.  2    may comprise a first film  311  and a second film  312 . During lamination, one or more structures  314  disposed on a second surface  317  of the second film  312  may be aligned, at step  320  of method  300 , and brought into contact with areas of a first surface  316  of the first film  311  defined by a predetermined distance  306  between one or more optical microstructures  305  disposed on the first surface  316  of the first film  311 , at step  325  of method  300 . Lamination can be achieved by a roll-to-roll process, among others. As can be appreciated from  FIG.  3 A , the laminate  310  may be designed such that a magnitude of a dimensional height  315  of the one or more structures  314  is greater than a magnitude of a dimensional height  307  of each of the one or more optical microstructures  305 . In this way, at least one void remains between the first film  311  and the second film  312  upon lamination. Following lamination, a void fill material  313  may be encapsulated, forming a surrounding medium, within at least a portion of the at least one void at step  330  of method  300 . The void fill material  313  may be a material having a predetermined refractive index. In an example, the void fill material  313  may be a gel, a solid, a fluid such as a liquid or a gas, or a combination thereof. The gas may be an impermeable gas and/or may be air, nitrogen, argon, xenon, and the like. The predetermined refractive index of the void fill material  313  may be 1.0. 
     According to an embodiment, the laminate  310  of  FIG.  3    may be incorporated onto a convex surface of a thermoplastic or thermoset optical lens, by methods such as front-side lamination (e.g. laminating a wafer on a convex surface of the lens), to produce an optical lens having optical microstructures on the convex side. 
     Referring now to  FIG.  4 A , a first film  411  may be a first material having a first refractive index. The first film  411  may have a one or more optical microstructures  405  disposed on a first surface  416  of the first film  411 . Each of the one or more optical microstructures  405  may have a dimensional height  407  and be separated from an adjacent one of the one or more optical microstructures  405  by a predetermined distance  406 . 
     According to an embodiment, the one or more optical microstructures  405  may be disposed on the first surface  416  of the first film  411  by one of a plurality of methods. In one instance, a nickel-platinum plated-shim or nickel-silicon plated-shim may be used to emboss a given optical microstructure architecture and design on the first surface  416  of the first film  411 . The nickel-platinum plated-shims and/or nickel-silicon plated-shims may include an array of the one or more optical microstructures to be embossed. The first film  411  may be heated to a temperature above a glass transition temperature (T g ) of the first material. In another instance, a stamp may be imprinted into the first surface  416  of the first film  411  to dispose the one or more optical microstructures  405  thereon. The imprinting may be aided by an ultraviolet process, wherein a thin-coated layer of ultraviolet-curable material is applied to the first surface  416  of the first film  411  and is then cured by ultraviolet light to solidify a pattern of the one or more optical microstructures  405  on the first surface  416  of the first film  411 . 
     Referring now to  FIG.  4 B , a second film  412  may be a second material having a second refractive index. The second film  412  may have a one or more structures  414  disposed on a first surface  417  of the second film  412 . Each of the one or more structures  414  may have a dimensional height  415  and be separated from an adjacent one of the one or more structures  415  by a predetermined distance corresponding to a predetermined distance between one or more optical microstructures of a first film of a laminate. This allows the one or more structures  415  to occupy at least a portion of a space not covered by the one or more optical microstructures of the first film. This may be referred to as ‘anti-microlens coverage’ of an ‘interstitial space’. The one or more structures  414  of the second film  412  may be flatter, smaller or larger, and occupy more or less space than the one or more optical microstructures of the first film. 
     According to an embodiment, the one or more structures  414  may be disposed on the first surface  417  of the second film  412  by one of a plurality of methods, described above with reference to  FIG.  4 A . In one instance, a nickel-platinum plated-shim or nickel-silicon plated-shim may be used to emboss a given architecture and design on the first surface  417  of the second film  412 . The nickel-platinum plated-shims and/or nickel-silicon plated-shims may include an array of the one or more structures to be embossed. The second film  412  may be heated to a temperature above a glass transition temperature (T g ) of the second material. In another instance, a stamp may be imprinted into the first surface  417  of the second film  412  to dispose the one or more structures  414  thereon. The imprinting may be aided by an ultraviolet process, wherein a thin-coated layer of ultraviolet-curable material is applied to the first surface  417  of the second film  412  and is then cured by ultraviolet light to solidify a pattern of the one or more structures  414  on the first surface  417  of the second film  412 . 
     According to an embodiment, and in view of the above, a first film  511  and a second film  512  of a laminate  510 , as in  FIG.  5   , may be laminated such that a void fill material is not encapsulated within at least a portion of at least one void between one or more optical microstructures  505  of the first film  511  and the second film  512 . The first film  511  may be a first material having a first refractive index. The second film  512  may be a second material having a second refractive index. As described above, the second refractive index may be different from the first refractive index. 
     In an embodiment, the first film  511  of the laminate  510  of  FIG.  5    may be fabricated according to one of a variety of methods described with respect to the above-described first film  411  of  FIG.  4 A . The second film  512  may be deposited on the first film  511  including one or more optical microstructures  505  by means of material deposition on a first surface of the first film  511 . Examples of deposition processes may include chemical vapor deposition, physical vapor deposition, inkjetting, dry or wet spray coating, electric or magnetic field assisted plating digital printing, and the like and may be followed by a densification process involving the application of heat and pressure. Such heat and pressure may be applied by an autoclave, between heated nipped rollers, in a flat plate stamp, and the like. Alternatively, a first surface, or contacting side, of the second film  512  may be heated to above its softening temperature by means of an infrared lamp, hot air, or convection, and brought into contact with the first surface of the first film  511  in a pressing process. The pressing process may include nipped rollers, a flat plate stamp, vacuum forming, or the like. 
     In an embodiment, a coating can be applied via a slot die coater to encapsulate one or more optical microstructures on a first film. The coating may be a thick coating and may be water-based, solvent-based, or solvent-less. The coating may be applied as a first coating type and a second coating type, wherein a volatile carrier (e.g., water, solvent) evaporate, leaving coating solids as a residue. A third coating type may be used to cure the coating. The third coating type may be one of thermal, ultraviolet, E-beam, and the like. The third coating type may be a third material having a third refractive index. The third material may be MR-8, having a refractive index of ~1.60, MR-10, having a refractive index of ~1.67, or any other plastic having a refractive index of between ~1.70 and ~1.74. 
     The above describe coatings, and similar coatings, may be applied using slot die, curtain, doctor blade or other thick film coating method to encapsulate the one or more optical microstructures. This application may be aided by use of a self-leveling coating material on top of the one or more optical microstructures of the first film to create the second film. The coating may be a solvent-less coating using energy-assisted curing, may be one of thermal, ultraviolet, E-beam, and the like, or may be solvent-based (e.g., water-based or VOC solvent-based) and dried and densified in a convection, conduction, or infrared oven. 
     In another embodiment, a second film of a laminate may be brought into contact with a first film of the laminate, the first film having one or more optical microstructures on a first surface thereof, and laminated by application of an adhesive. The adhesive may be a water-based adhesive, solvent-based adhesive, or solvent-less adhesive, as appropriate. 
     In another embodiment, in view of  FIG.  5   , a second film of a laminate may be brought into contact with a first film of the laminate by extrusion lamination. The first film of the laminate may include one or more optical microstructures. During extrusion lamination, the second film may be a hot extruded film and may be brought into contact with the first film via nip roller. 
     With reference now to  FIG.  6 A  and  FIG.  6 B , any one of the above-described laminates, as a non-limiting group, may be cut, formed into curved wafers, and incorporated into an optical lens  601 . The incorporation of a laminate  610 , including optical microstructures, may be performed by, among other techniques, injection overmolding, wafer casting (i.e., on-surface or in-lens), or pressure and/or heat assisted “front-side lamination” and/or “back-side lamination” onto existing semi-finished and/or finished lenses. Any one of the above-identified techniques may require one or both surfaces of the laminate to contain, or be coated with, a primer layer or adhesive layer (e.g., pressure-sensitive adhesive, hot-melt adhesive) to facilitate adhesion to the lens substrate material. As in  FIG.  6 A , a laminate  610  may be adhered to a convex surface of an optical lens  601 , thus arranging the laminate  610  opposite a surface of the optical lens  601  adjacent an eye of an eyeglass wearer. As in  FIG.  6 B , a laminate  610  may be adhered to a concave surface of an optical lens  601 , thus arranging the laminate  610  on a surface of the optical lens  601  adjacent an eye of an eyeglass wearer. The optical lens  610  may be an existing thermoplastic or thermoset optical lens. 
     According to an embodiment, and with reference to  FIG.  7 A  and  FIG.  7 B , a laminate, or wafer  710 , including one or more optical microstructures  705  and having refractive index RI waƒer , may be prepared according to a concave surface of an optical lens  701  and then laminated onto a convex surface of the optical lens  701 . The optical lens  701  may have refractive index RI lens . The one or more optical microstructures may be microlenses and, in particular, microlenses of the Fresnel-lens type. The lamination may be facilitated by use of an adhesive  702  of refractive index RI adh . The adhesive  702  may be a water-based adhesive, solvent-based adhesive, or solvent-less adhesive, as appropriate. Of course, as an alternative, a laminate  710  may be prepared according to a convex surface of an optical lens  701  and then laminated onto the concave surface of the optical lens  701 , as desired. 
     In an embodiment, the resulting diopter powers of the one or more optical microstructures is dependent upon ΔRI = (RI wafer  - RI adh ) and is independent of RI lens,  assuming that RI waƒer  ≠ RI adh . In this way, it can be appreciated that substrate material is immaterial to the function of the laminate when the laminate and the adhesive are carefully selected. 
     According to an embodiment, the laminate may be produced by, in addition to the methods described above, injection molding. The lamination step can be performed during injection molding of an optical thermoplastic lens by an in-mold lamination process, thus making the process scalable for mass production. Additionally, the lamination may be carried out in a prescribing lab by “front-side lamination” or “back-side lamination” based upon the desired result. 
     In other words, a variety of fabrication options exist. In at least one option, a laminate, as described above, may be positioned within a mold prior to forming an optical lens. In at least one option, a laminate can be adhered and/or bonded to an already formed optical lens. For instance, in order to form thermoplastic polycarbonate (PC) lenses, a laminate can be overmolded on a convex surface of the lens. In other words, a molten PC may be injected behind the laminate. In another instance, for thermoset cast lenses, a laminate can be positioned on a surface of a casting mold or the laminate may be offset from the surface of the casting mold by 0.1 mm to 1.0 mm. In this way, at least a portion of at least one void therebetween may be filled with thermoset monomers/resin and allowed to cure. A primer layer may be required to allow a surface of the laminate to bond to the thermoset monomers/resin. 
     Obviously, numerous modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. 
     Embodiments of the present disclosure may also be as set forth in the following parentheticals. 
     (1) A laminate, comprising a first film, of a first material having a first refractive index, including a pattern of microstructures embossed on a first surface of the first film, each microstructure of the embossed pattern of microstructures being an optical microstructure arranged at a predetermined distance between adjacent optical microstructures, and a second film, of a second material having a second refractive index, including structures arranged on a first surface of the second film at positions corresponding to areas of the first surface of the first film defined by the predetermined distance between adjacent optical microstructures, wherein when the second film is laminated to the first film, the structures arranged on the first surface of the second film are in contact with the areas of the first surface of the first film defined by the predetermined distance between adjacent optical microstructures, a height of the structures of the second film is greater than a height of each optical microstructure, and a delta between the height of the structures of the second film and the height of each optical microstructure encapsulates, upon the lamination of the second film to the first film, a void fill material within at least a portion of at least one void defined by the delta, the void fill material having a predetermined refractive index. 
     (2) The laminate according to (1), wherein the laminate is laminated on a convex surface of a lens, the convex surface of the lens being opposite a surface of the lens adjacent an eye of a lens wearer, a second surface of the first film being in contact with the convex surface of the lens. 
     (3) The laminate according to either (1) or (2), wherein the laminate is laminated on a convex surface of a lens, the convex surface of the lens being opposite a surface of the lens adjacent an eye of a lens wearer, a second surface of the second film being in contact with the convex surface of the lens. 
     (4) The laminate according to any one of (1) to (3), wherein the first refractive index of the first material is different from the predetermined refractive index of the void fill material. 
     (5) The laminate according to any one of (1) to (4), wherein the first refractive index of the first material is greater than 1.4. 
     (6) The laminate according to any one of (1) to (5), wherein the first material of the first film and the second material of the second film are a same thermoplastic. 
     (7) The laminate according to any one of (1) to (6), wherein the void fill material is an impermeable gas. 
     (8) A method of generating a laminate, comprising laminating a first film of the laminate, the first film being a first material having a first refractive index, to a second film of the laminate, the second film being a second material having a second refractive index, by contacting structures arranged on a first surface of the second film with areas of a first surface of the first film defined by a predetermined distance between adjacent optical microstructures, wherein each optical microstructure is a microstructure of a pattern of microstructures embossed on the first surface of the first film and arranged at the predetermined distance between adjacent optical microstructures, the structures on the first surface of the second film are arranged to correspond with the areas of the first surface of the first film defined by the predetermined distance between adjacent optical microstructures, a height of the structures on the first surface of the second film is greater than a height of each optical microstructure embossed on the first surface of the first film, and a delta between the height of the structures on the first surface of the second film and the height of each optical microstructure embossed on the first surface of the first film encapsulates, upon the laminating of the first film and the second film, a void fill material within at least a portion of at least one void defined by the delta, the void fill material having a predetermined refractive index. 
     (9) The method according to (8), further comprising laminating the laminate on a convex surface of a lens, the convex surface of the lens being opposite a surface of the lens adjacent an eye of a lens wearer, a second surface of the first film being in contact with the convex surface of the lens. 
     (10) The method according to either (8) or (9), further comprising laminating the laminate on a convex surface of a lens, the convex surface of the lens being opposite a surface of the lens adjacent an eye of a lens wearer, a second surface of the second film being in contact with the concave surface of the lens. 
     (11) The method according to any one of (8) to (10), wherein the laminating includes applying an adhesive to a contacting surface of the structures arranged on the first surface of the second film and to the areas of the first surface of the first film defined by the predetermined distance between adjacent optical microstructures. 
     (12) The method according to any one of (8) to (11), wherein the first refractive index of the first material is different from the predetermined refractive index of the void fill material. 
     (13) The method according to any one of (8) to (12), wherein the first refractive index of the first material is greater than 1.4. 
     (14) The method according to any one of (8) to (13), wherein the first material of the first film and the second material of the second film are a same thermoplastic. 
     (15) The method according to any one of (8) to (14), wherein the void fill material is an impermeable gas. 
     Thus, the foregoing discussion discloses and describes merely exemplary embodiments of the present invention. As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting of the scope of the invention, as well as other claims. The disclosure, including any readily discernible variants of the teachings herein, defines, in part, the scope of the foregoing claim terminology such that no inventive subject matter is dedicated to the public.