Thermoformed windshield stack with one-piece moldable mold

Abstract

Fabricating a pre-formed stack of one or more lenses that can be attached to a curved substrate, such as an automobile windshield, includes placing a formable stack of one or more lenses and an adhesive layer in a mold, applying heat and pressure to the formable stack to fabricate a pre-formed stack of one or more lenses from the formable stack, and removing the pre-formed stack from the mold. The pre-formed stack can have a compound curvature. The compound curvature can match the curvature of the curved substrate. The mold can be formed using three-dimensional shape data obtained from the curved substrate, such as by optically scanning the curved substrate.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates generally to window glazings, and more particularly to glazings having multiple laminated lenses adhered together by an adhesive. [Background technology]

[0002] Applying transparent lenses to a curved substrate, such as a windshield (also called a windscreen), can have various advantages. Such coverings can provide protection from pitting and cracking, coloring (e.g., for privacy), thermal insulation, ultraviolet (UV) radiation blocking, and / or decoration. Stacking such transparent lenses can allow for easy tear-away when the outermost lens becomes soiled and obstructs the driver's view, as can occur in off-road vehicles.

[0003] The surface of a typical windshield usually exhibits a compound curvature. However, the transparent lens itself may be flat, as in the case of polyethylene terephthalate (PET) films manufactured using a roll-to-roll process. To attach a flat film to a compound-curved windshield surface, for example, the film is laid over the windshield and heat is applied to the upper surface, causing the film to shrink or stretch to conform to the shape of the windshield, allowing the film to be draped over the windshield. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 6,536,045 [Patent Document 2] U.S. Patent No. 9,295,297 [Patent Document 3] U.S. Patent No. 9,128,545 Summary of the Invention [Problem to be solved by the invention]

[0005] However, this method can result in uneven or overheating, which can cause optical distortion in the film or areas where the film does not adhere well to the windshield. Additionally, installers who apply pressure to the film with cards or squeegees can permanently scratch the visible surface during installation. [Means for solving the problem]

[0006] The present disclosure contemplates various systems and methods for overcoming the above-described drawbacks associated with the related art. One aspect of an embodiment of the present disclosure is a method for installing a stack of two or more lenses on a curved substrate. The method may include placing a moldable covering on the curved substrate. The moldable covering includes the stack of two or more lenses, an adhesive layer interposed between each pair of adjacent lenses from among the two or more lenses, and a sacrificial layer disposed on an outermost lens of the stack. The sacrificial layer includes a sacrificial lens and a sacrificial adhesive. The sacrificial adhesive is interposed between the sacrificial lens and the outermost lens of the stack. The method can include applying heat and pressure to the sacrificial layer to peel off the sacrificial layer, thereby revealing a stack of two or more lenses.

[0007] The curved substrate may be a compound curved substrate. The curved substrate may be a windshield. The sacrificial layer may be more heat resistant than the outermost lens of the stack.

[0008] The sacrificial layer may be less scratch resistant than the outermost lens of the stack. The sacrificial lens may be constructed with a biaxially oriented polyethylene terephthalate film that can withstand temperatures between room temperature and 220° C. for 2 hours.

[0009] The sacrificial lens may be constructed with an opaque polyester film. The outermost lens of the stack may be constructed with a transparent polyethylene terephthalate film. Another aspect of an embodiment of the present disclosure is a formable cover that can be applied to a curved substrate. The formable cover can include a stack of two or more lenses, an adhesive layer interposed between each pair of adjacent lenses from the two or more lenses, and a sacrificial layer disposed on an outermost lens of the stack. The sacrificial layer includes a sacrificial lens and a sacrificial adhesive. The sacrificial adhesive is interposed between the sacrificial lens and the outermost lens of the stack. The sacrificial layer has a higher heat resistance than the outermost lens of the stack.

[0010] The sacrificial lens may be constructed with a biaxially oriented polyethylene terephthalate film that can withstand temperatures between room temperature and 220° C. for 2 hours.

[0011] The sacrificial lens may comprise an opaque polyester film, and the outermost lens of the stack may comprise a transparent polyethylene terephthalate film. Another aspect of an embodiment of the present disclosure is a formable cover that can be applied to a curved substrate. The formable cover can include a stack of two or more lenses, an adhesive layer interposed between each pair of adjacent lenses from the two or more lenses, and a sacrificial layer disposed on an outermost lens of the stack. The sacrificial layer comprises a sacrificial lens and a sacrificial adhesive. The sacrificial adhesive is interposed between the sacrificial lens and the outermost lens of the stack. The sacrificial layer has lower scratch resistance than the outermost lens of the stack.

[0012] The sacrificial lens may be constructed with a biaxially oriented polyethylene terephthalate film that can withstand temperatures between room temperature and 220° C. for 2 hours.

[0013] The sacrificial lens may be constructed with an opaque polyester film. The outermost lens of the stack may be constructed with a transparent polyethylene terephthalate film. Another aspect of an embodiment of the present disclosure is a method for producing a molded stack of lenses that can be mounted on a curved substrate. The method may include placing a moldable stack of lenses onto a mold. The moldable stack of lenses includes two or more lenses and an adhesive layer between each pair of adjacent lenses from the two or more lenses. The method may further include applying heat and pressure to the moldable stack of lenses to produce a pre-molded stack of lenses from the moldable stack of lenses, and removing the pre-molded stack of lenses from the mold.

[0014] Another aspect of an embodiment of the present disclosure is a method for manufacturing a pre-formed stack of one or more lenses that can be attached to a curved substrate. The method may include placing a formable stack of one or more lenses on a mold. The formable stack includes one or more lenses and one or more adhesive layers respectively disposed thereon. The method may further include applying heat and pressure to the formable stack to produce a pre-formed stack of one or more lenses from the formable stack of one or more lenses, and removing the pre-formed stack of one or more lenses from the mold.

[0015] Either of the two methods may include a step of deriving three-dimensional shape data from a curved substrate and a step of forming a mold using the three-dimensional shape data. The deriving of the three-dimensional shape data may include a step of optically scanning the curved substrate. The curved substrate and the mold may be the same type of windshield. The mold may be composed of a compound curved surface.

[0016] The step of applying heat and pressure can include disposing multiple heaters on a frame positioned to direct the heaters toward the formable stack. The step of applying heat and pressure can include pressing the formable stack with one or more rollers.

[0017] The moldable stack can include a sacrificial layer disposed on an outermost lens of the stack. The sacrificial layer can include a sacrificial lens and a sacrificial adhesive. The sacrificial adhesive is interposed between the sacrificial lens and the outermost lens of the stack. The sacrificial layer can be more heat resistant than the outermost lens of the stack. The sacrificial layer can be less scratch resistant than the outermost lens of the stack. The sacrificial lens can include a biaxially oriented polyethylene terephthalate film. The biaxially oriented polyethylene terephthalate film can withstand temperatures between room temperature and 220°C for two hours. The sacrificial lens can be comprised of an opaque polyester film. The outermost lens of the stack can be comprised of a transparent polyethylene terephthalate film.

[0018] Another aspect of an embodiment of the present disclosure is a pre-formed stack of two or more lenses that can be mounted on a curved substrate. The pre-formed stack may include a stack of two or more lenses and an adhesive layer between each pair of adjacent lenses from the two or more lenses. The pre-formed stack may have a compound curvature.

[0019] Each of the two or more lenses may be constructed with a biaxially oriented polyethylene terephthalate film. These and other features and advantages of the various embodiments disclosed herein will become better understood with regard to the following description and drawings. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic side view of a formable jacket according to an embodiment of the present disclosure. [Figure 2] FIG. 10 illustrates the formable cover positioned on the windshield at the beginning of the process of applying heat and pressure to the sacrificial layer of the formable cover. [Figure 3] 1 illustrates the formable covering positioned on the windshield at the end of the heat and pressure application process. [Figure 4]FIG. 10 shows the formable coating on the windshield as the sacrificial layer is peeled away to expose the stack of transparent lenses. [Figure 5] A diagram showing the stack of clear lenses after they have been trimmed to fit the windshield. [Figure 6] FIG. 1 illustrates an exemplary operational flow according to an embodiment of the present disclosure. [Figure 7] FIG. 10 shows a frame for positioning a moldable stack of one or more lenses, a mold for manufacturing a pre-formed stack of lenses, and multiple heaters and / or rollers according to another embodiment of the present disclosure. [Figure 8] FIG. 10 illustrates an exemplary operational flow according to another embodiment of the present disclosure. [Figure 9] FIG. 10 illustrates an exemplary sub-operational flow of step 840 of FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present disclosure encompasses various embodiments of formable jackets comprising a stack of two or more lenses and methods for attaching the same, as well as various embodiments of pre-formed stacks of lenses and methods for manufacturing the same. The detailed description set forth below in connection with the accompanying drawings is intended as a description of some currently contemplated embodiments and is not intended to represent the only manner in which the disclosed invention may be developed or utilized. This specification defines functions and features in connection with the illustrated embodiments. However, it is understood that the same or equivalent functions may be achieved by different embodiments that are intended to be encompassed within the scope of the present disclosure. Furthermore, it should be understood that relational terms such as first and second are used only to distinguish one entity from another, without necessarily requiring or implying any actual relationship in the order between such entities.

[0022] FIG. 1 is a schematic side view of a moldable jacket 100 according to an embodiment of the present disclosure. The moldable jacket 100 can be affixed to a curved substrate 10, such as a windshield, as part of an installation process for a stack of lenses 110a, 110b, ... 110n (collectively, lenses 110). The stack of installed lenses 110 can provide the substrate 10 with protection, color, thermal insulation, ultraviolet (UV) radiation blocking, decoration, and / or the ability to peel and discard the outermost layer 110n (hereinafter, newly exposed layer 110) as needed during the product's life. In addition to the lenses 110, the moldable jacket 100 can include adhesive layers 120a, 120b, ... 120n (collectively, adhesive layers 120). An adhesive layer 120 is provided on each lens 110 such that the adhesive layer 120 is interposed between each pair of adjacent lenses 110 in the stack. The outermost lens 110n of the stack of lenses 110 may be provided with a sacrificial layer 130 to improve the process of attaching the stack of lenses 110 to the substrate 10. The sacrificial layer 130 may include a sacrificial lens 132 and a sacrificial adhesive 134. The sacrificial adhesive 134 is interposed between the sacrificial lens 132 and the outermost lens 110n of the stack of lenses 110. During attachment of the stack of lenses 110, heat and pressure can be applied to the sacrificial layer 130 to cause the stack of lenses 110 to conform to the shape of the curved substrate 10. The sacrificial layer 130 can then be peeled away to reveal a final product 140 including the attached lenses 110.

[0023] Simply draping a stack of lenses 110 onto a curved substrate 10 without the sacrificial layer 130 not only results in uneven heating and overheating as described above, but also risks permanently damaging the outermost lenses 110n with a card or squeegee. The inventors have discovered that these difficulties are primarily due to the lack of a female cavity to apply pressure as the stack of lenses 110 conforms to the male surface presented by the curved substrate 10. As a result, when an installer attempts to mold the stack of lenses 110 onto the curved substrate 10, neither heat nor pressure is distributed evenly, resulting in the aforementioned difficulties. By providing the sacrificial layer 130 to function as the missing female cavity, the disclosed moldable enclosure 100 is enabled to overcome these deficiencies in at least two ways. First, the sacrificial layer 130 allows the installer to apply heat and pressure without worrying about scratching or otherwise damaging the final product. Because the sacrificial layer 130 is simply discarded along with any surface damage, the outermost lens 110n of the stack of lenses 110 remains uncontaminated. Second, when heat and pressure are applied to the stack of lenses 110 through the sacrificial layer 130, the sacrificial layer 130 serves to distribute the heat and pressure over a wider area. Thus, the sacrificial layer 130 and the stack of lenses 110 below the sacrificial layer 130 together conform to the shape of the curved substrate 10, allowing the heat and pressure to be applied more evenly.

[0024] Lenses 110 may be constructed of a transparent polyethylene terephthalate (PET) film, such as biaxially oriented polyethylene terephthalate (BoPET), or may be made from sheets of polyester film sold under the trademark Mylar, owned by DuPont. Each lens 110 may have a thickness ranging from 0.5 mils (0.0127 mm) to 7 mils (0.1778 mm, where 1 mil is 0.001 inches (0.0254 mm)), such as 2 mils (0.0508 mm). Even after the adhesive material of adhesive layer 120 is applied to 2 mil-thick lenses 110, adhesive layer 120 still has only a nominal thickness. Thus, the combined thickness of 2 mil-thick lenses 110 and adhesive layer 120 may still be 2 mils (0.0508 mm).

[0025] The adhesive used for adhesive layer 120 can be applied to selective areas around the periphery of moldable enclosure 100, as described, for example, in U.S. Patent No. 6,239,999 to Wilson, entitled "Tear-Off Optical Stack Hubing Peripheral Seal Mount," issued March 25, 2003, the entire contents of which are expressly incorporated herein by reference. Adhesive layer 120 can be made of a transparent, optically low-tack material or can be composed of a water-based acrylic optically clear adhesive or an oil-based clear adhesive. Adhesive layer 120a used to attach moldable enclosure 100 to substrate 10 can be the same as or different from adhesive layers 120b, ..., 120n (e.g., stronger than adhesive layers 120b, ..., 120n). Adhesive layers 120b, ..., 120n are interposed between adjacent lenses 110 in each pair of the stack. For example, stronger adhesives can be used to separate individual lenses 110 without removing the entire stack of lenses 110 from the substrate 10 during use. Along the same lines, the adhesive used for the adhesive layers 120b, ..., 120n between each pair of adjacent lenses 110 may be stronger than the sacrificial adhesive 134 of the sacrificial layer 130. As a result, such a sacrificial layer 130 can be torn off without removing the outermost lens 110n from the stack of lenses 110. The sacrificial adhesive 134 may similarly be a low-tack material or comprise a water-based acrylic optically clear adhesive or an oil-based clear adhesive. However, in the case of the sacrificial adhesive 134, an opaque adhesive may be used instead, since the sacrificial adhesive 134 will be removed in the final product 140.

[0026] The lenses 110 may be optimized for scratch resistance and / or UV radiation blocking (absorption or reflection). For example, the outer surface of each lens 110 may be vapor-deposited, sprayed, laminated, or otherwise coated with a coating optimized for scratch resistance and / or UV radiation blocking (e.g., silicone ester acrylate oligomer and / or acrylated urethane polyol), as desired for the final product 140. These properties may be relaxed during the fabrication of the sacrificial layer 130 because the sacrificial layer 130 will not be present after installation is complete. Thus, for example, the sacrificial layer 130 may be less scratch-resistant than the outermost lens 110n of the stack of lenses 110. Alternatively, the sacrificial layer 130 may be coated with a coating optimized for heat resistance (e.g., silicone ester acrylate oligomer and / or acrylated urethane polyol), for example, since the sacrificial layer 130 may be directly heated as part of thermoforming the moldable enclosure 100 to the shape of the curved substrate 10. Such heat resistance properties may be relaxed for the underlying stack of lenses 100, which only experience heat indirectly through the sacrificial layer 130. Thus, for example, the sacrificial layer 130 may be more heat resistant than the outermost lens 110n of the stack of lenses 100.

[0027] The sacrificial layer 130 may be made of high-temperature PET, for example, capable of withstanding temperatures between room temperature and 220°C (e.g., without degradation) for two hours. The high-temperature PET may be transparent biaxially oriented polyethylene terephthalate (BoPET), such as a polyester film sold by Mitsubishi Polyester Film Group under the trade name Hostaphan RBB, to allow observation of the underlying stack of lens 110 during the molding process. Such high-temperature biaxially oriented polyethylene terephthalate (BoPET) may be preferable when hot air is used to heat the sacrificial layer 130 during the molding process. Alternatively, the sacrificial layer 130 may be made of an opaque (e.g., white) polyester film, such as that sold by Mitsubishi Polyester Film Group under the trade name Hostaphan WIN. Such an opaque polyester film can improve thermal uniformity when an infrared heater is used to heat the sacrificial layer 130 during the molding process.

[0028] The sacrificial layer 130 (e.g., the sacrificial lens 132 and / or the sacrificial adhesive 134) may be optimized to withstand the heat of the installation process and evenly distribute heat and pressure to the stack underlying the lens 110. However, the sacrificial layer 130 is generally not required to meet the more stringent performance standards of the stack underlying the lens 110. For example, the lens stack may be designed to meet federal standards for visible light transmittance (e.g., 70%), such as may be specified in American National Standards Institute (ANSI) standards Z26.1-1966 and Z26.1a-1969, and may be designed to resist scratches (e.g., from windshield wipers) and / or to protect the lens 110 from sun damage by absorbing or reflecting ultraviolet light, as described above. By relaxing these requirements on the sacrificial layer 130 while providing a more robust surface for the application of heat and pressure without concern during installation, the formable enclosure 100 may enable a more efficient method of attaching the lens 110 stack. With the sacrificial layer 130 acting as a female cavity, the lens 110 and adhesive layer 120 layers are well held, formed, and cured by the curved substrate 10, and will not be scratched during the installation process.

[0029] FIG. 2 shows the formable cover 100 positioned on the windshield of an automobile 20. The windshield serves as the substrate 10. FIG. 2 illustrates the beginning of a process in which heat and pressure are applied to the sacrificial layer 130 of the formable cover 100. The formable cover 100 may be adhered to the windshield with a dry mount adhesive (120a, see FIG. 1), as disclosed, for example, in U.S. Patent No. 6,229,623 to Wilson, entitled "Adhesive Mountable Stack of Removable Layers," issued March 29, 2016, the entire contents of which are expressly incorporated herein by reference. Alternatively, a wet mount adhesive (120a) may be used, as disclosed, for example, in U.S. Patent No. 6,229,623 to Wilson, entitled "Touchscreen Shield," issued September 8, 2015, the entire contents of which are expressly incorporated herein by reference. Because the formable covering 100 may be flat (e.g., manufactured using a roll-to-roll process), the formable covering 100 may not initially conform to the curved shape of the windshield, potentially resulting in areas of high or low adhesion and air pockets / bubbles between the formable covering 100 and the windshield. Therefore, to force the formable covering 100 to conform to the shape of the windshield, heat and pressure can be applied using a heater 30, such as a hot air source (e.g., a heat gun or blow dryer) or an infrared heater. Simultaneous pressure can also be applied to the formable covering 100 using a card or squeegee. When an installer applies heat and pressure to the sacrificial layer 130 of the formable covering 100, the sacrificial layer 130 shrinks and stretches, allowing the stack of lenses 110 to be sandwiched between the sacrificial layer 130 and the sacrificial layer 130 to conform to the contours of the opposing curved substrate 10 (windshield). In this way, the sacrificial layer 130 acts as a female cavity for thermoforming the stack of lenses 110 that resides beneath the sacrificial layer 130 into the shape of the windshield.That is, the sacrificial layer 130 is capable of evenly distributing heat and pressure to cure the adhesive layer 120 while shrinking and expanding the lens 110 to the correct shape.

[0030] 3 shows the formable cover 100 on the windshield at the end of the heat and pressure process. At this stage, the formable cover 100, including the underlying lens 110 and sacrificial layer 130, has molded to the curved shape of the windshield without any air pockets or bubbles. The top surface of the sacrificial layer 130 may have various scratches or blemishes caused by the installer applying pressure to the formable cover 100 using a squeegee or card. However, the underlying lens 110 remains untouched because it is protected by the sacrificial layer 130.

[0031] FIG. 4 shows the formable coating 100 on a windshield when the sacrificial layer 130 is peeled away to expose the stack of transparent lenses 110. What remains on the windshield is the final product 140 (see FIG. 1). The final product 140 includes the stack of lenses 110 and the adhesive layer 120. The final product 140 can meet performance standards such as those described above, including federal standards for visible light transmittance (e.g., 70%), scratch resistance, and / or UV absorption or rejection. The lenses 110 of the final product 140 can precisely conform to the shape of the windshield. Even the outermost lenses 110n can be scratch-free. The peeled sacrificial layer 130 can simply be discarded.

[0032] FIG. 5 shows a final product 140 comprising a stack of transparent lenses 110 after the stack of transparent lenses 110 has been trimmed to fit the windshield, which serves as substrate 10. The stack of transparent lenses 110 can be trimmed using a knife, such as a utility knife or box cutter, with a stainless steel blade (carbon blades may damage the windshield). Trimming may occur after the sacrificial layer 130 has been removed from the formable enclosure 100, as shown in FIG. 5, so that only the exposed final product 140 is trimmed. Alternatively, trimming may occur after the formable enclosure 100 has conformed to the shape of the windshield and before the sacrificial layer 130 has been removed, as shown in FIG. 3. In either case, the resulting trimmed final product 140 may be substantially invisible (although it may change the tint of the windshield, as in the case of window tint) because it conforms to the shape of the windshield underneath the final product 140.

[0033] FIG. 6 illustrates an exemplary operational flow according to an embodiment of the present disclosure. The operational flow of FIG. 6 may serve as an exemplary method for installing a final product 140 comprising a stack of lenses 110 as shown in FIG. 1. First, the formable covering 100, comprising both the final product 140 and the sacrificial layer 130, may be placed on a curved substrate 10, such as the windshield of the automobile 20 shown in FIG. 2, with the adhesive layer 120a on the windshield and the sacrificial layer 130 facing outward, away from the windshield (step 610). To facilitate attachment, the formable covering 100 may be roughly cut (e.g., using an electric film cutter) so that it does not protrude too far outward from the windshield. The operational flow may continue by applying heat and pressure to the sacrificial layer 130 of the formable covering 100, as described in connection with FIGS. 2 and 3, to thermoform the formable covering 100 to the curved shape of the windshield (step 620). After allowing the formable envelope 100 to cool, the operational flow can conclude with stripping away the sacrificial layer 130 to expose the final product 140 (step 630), as described in connection with Figure 4, and final trimming (step 640), as described in connection with Figure 5. As noted above, steps 630 and 640 may be performed in the order shown in Figure 6, or in reverse order. The final product 140, comprising the stack of lenses 110, is now uniformly formed and is then affixed to the windshield surface.

[0034] As described above, aspects of the disclosed subject matter enable the manufacture of a formable enclosure 100 comprising a stack of lenses 110 that are molded into place on an end user's vehicle windshield or other curved substrate 10. To this end, the formable enclosure 100 can comprise a sacrificial layer 130 that protects the underside of the stack of lenses 110 and serves as a female mold cavity. This allows an installer to easily and effectively mold the stack of lenses 110 using common equipment (e.g., a blow dryer and card) without risk of uneven heating or damage to the lenses 110. While these aspects can be of great benefit to users who wish to self-install a stack of lenses 110 with minimal risk, as described above, further simplification of the installation process may be desirable. For example, a user may be unable or unwilling (or simply unsure) to apply the heat and pressure necessary to form the formable covering 100 to the shape of their windshield 10 (step 620 of FIG. 6 ) or subsequently trim the formable covering (step 640 of FIG. 6 ). Accordingly, to further ease the burden on the installer, an additional aspect of the disclosed subject matter relates to the manufacture of a pre-molded stack of lenses 110 that are already shaped (all-ready-molded, and optionally already trimmed) to the shape of a vehicle windshield or other curved substrate 10. The installer is enabled to simply apply the stack of pre-molded lenses 110 to the curved substrate 10 (e.g., by exposing and / or activating adhesive layer 120 a and placing the stack of lenses 110 on the curved substrate 10) without having to worry about shaping and / or trimming the lenses 110 to fit the curved substrate 10.

[0035] 1 and 7, a pre-formed stack of lenses 110 can be fabricated from a moldable stack 700 that is identical to the moldable enclosure 100 shown in FIG. 1 or the previously described unmolded final product 140 (i.e., the moldable enclosure 100 but without the sacrificial layer 130). That is, similar to that described above with respect to the moldable enclosure 100, the moldable stack 700 can include two or more lenses 110 and an adhesive layer 120 interposed between each pair of adjacent lenses from the two or more lenses 110. (Note that the final product 140 of FIG. 1 can also represent a pre-formed stack of lenses 110, i.e., the moldable stack 700 after deformation as described herein.) As described in more detail below, the moldable stack 700 can generally be professionally shaped to fit a curved substrate 10 using specialized equipment and expertise with minimal risk of uneven heating / pressure or scratches to the outermost lenses 110. Thus, the sacrificial layer 130 described above may typically be omitted, although it is contemplated that the sacrificial layer 130 may be included and the formable stack 700 would thus be identical to the formable enclosure 100 shown in FIG.

[0036] Referring to FIG. 7 , the formable stack 700 can be placed on a suitably shaped mold 40, particularly a mold 40 that matches the curvature (typically a compound curve) of a vehicle windshield or other substrate 10 onto which the preformed stack of lenses 110 will ultimately be installed. The mold 40 can function as a lower mold (convex mold) or can be comprised of a compound curve. The mold 40 can be, for example, a windshield of the same type (e.g., model, shape, size) as the substrate 10 onto which the preformed stack of lenses 110 will be attached. In this regard, manufacturers of preformed stacks of lenses 110 are enabled to stock a variety of windshields currently available on the market for use with each mold 40. When an order for a preformed stack of lenses 110 is placed, the order can include instructions for the type of windshield the stack of lenses 110 should be preformed to fit. The moldable stack 700 can then be molded into a pre-formed stack of lenses 110 using the same type of windshield as the mold 40. Alternatively, the mold 40 can be formed using three-dimensional shape data of the windshield or other curved substrate 10 onto which the pre-formed stack of lenses 110 will be placed. For example, the curved substrate 10 can be optically scanned to derive three-dimensional shape data such as a polygonal model (e.g., a wireframe), and the mold 40 can be formed to fit the substrate 10 using the derived three-dimensional shape data. In this manner, the mold 40 can be custom molded to precisely match a customer's windshield.

[0037] Various techniques can be used to uniformly apply heat and pressure to the moldable stack 700 while it resides on the mold 40. FIG. 7 illustrates the use of a frame 50 (e.g., an aluminum truss or other lightweight support structure) located adjacent to the mold 40 and capable of supporting multiple heaters 60 for heating the moldable stack 700. The heaters 60 (e.g., hot air sources and / or infrared heaters) can be positioned on the frame 50 and directed toward the moldable stack 700. For example, the frame 50 can define a grid of attachment points that can be located along the illustrated horizontal and vertical bars that make up the illustrated frame 50. It is contemplated that the heaters 60 can be freely attached to the frame 50 so as to be evenly spaced apart on the moldable stack 700 as desired. The exact location of the heaters 60 can be adjusted depending, for example, on the size and shape of the mold 40. While heater 60 heats moldable stack 700, moldable stack 700 may also be pressed by one or more rollers 70, which may be attached to frame 50, for example, by one or more tracks and / or pivot points. Rollers 70 may be made of high-density foam. Rollers 70 may typically be configured with a pair of rollers 70 pressing against moldable stack 700 at the center and rolling away from each other (in the direction of the arrows in FIG. 7 ) to press moldable stack 700 downward against mold 40 while allowing lens 110 material to deform outward.

[0038] FIG. 8 illustrates an exemplary operational flow according to another embodiment of the present disclosure. FIG. 9 illustrates an exemplary sub-operational flow of step 840 of FIG. 8. The operational flows of FIGS. 8 and 9 may serve as an exemplary method for manufacturing a pre-formed stack of lenses 110 that can be attached to a curved substrate 10. The operational flow may begin with deriving three-dimensional shape data associated with the curved substrate 10 onto which the pre-formed stack of lenses 110 will ultimately be attached (e.g., by optically scanning the substrate 10) (step 810), and using the three-dimensional shape data to form a mold 40 (see FIG. 7) (step 820). Note that steps 810 and 820 may be omitted, instead of pre-forming the mold 40, such as when using various windshields known as molds 40, as described above. In this case, the mold 40 need only be selected according to the particular curved substrate 10 onto which the pre-formed stack of lenses 110 is intended to be attached. In either case, the operational flow can continue by placing moldable stack 700 (having lens 110) on mold 40 (step 830). As explained above, moldable stack 700 can be identical to moldable enclosure 100 shown in FIG. 1, or sacrificial layer 130 can be omitted.

[0039] Once the moldable stack 700 is placed on the mold 40, the operational flow of FIG. 8 continues with the application of heat and pressure to the moldable stack 700, resulting in the production of a pre-molded stack of lenses 110 (step 840). In some cases, the heat and pressure application process may proceed exactly as described above in connection with FIGS. 2-5, except that the mold 40 is used in place of the actual substrate 10 onto which the pre-molded stack of lenses 110 will ultimately be placed. Similarly, if a simple handheld heat source and a squeegee or card for applying pressure are used, it may be beneficial for the manufacturer of the pre-molded stack of lenses 110 to have the moldable stack 700 include a sacrificial layer 130. Preferably, however, specialized equipment is used to ensure even heating and safe application of pressure without damaging the outermost lenses 110, eliminating the need for a sacrificial layer 130. For example, referring to the sub-operational flow of Figure 9, the application of heat and pressure can be achieved by positioning heater 60 on frame 50 to direct heater 60 toward moldable stack 700 (step 842), as shown in Figure 7, and further pressing moldable stack 700 with one or more rollers 70 (step 844). In this manner, heat and pressure can be uniformly applied to moldable stack 700 to promote the necessary shrinkage and expansion of lenses 110 and curing of adhesive layer 120.

[0040] After sufficient heat and pressure has been applied to force the moldable stack 700 to conform to the shape of the mold 40, typically after cooling and trimming excess material around the perimeter of the mold 40 (and peeling away the sacrificial layer 130, if applicable), as described above in connection with FIG. 5 , the resulting pre-formed stack of lenses 110 can be removed from the mold 40 (step 850). The pre-formed stack of lenses 110 can then be shipped or otherwise delivered to a customer so that the customer can attach it with minimal effort to their windshield or other curved substrate 10 (step 860). For example, during delivery, a release liner or backing film may be provided on the innermost adhesive layer 120 a of the pre-formed stack of lenses 110, or the adhesive layer 120 a may be otherwise inactive. The customer simply peels off the release liner and places the stack of lenses 110 on their windshield 10, or simply places the stack of lenses 110 on the windshield 10 and activates the adhesive layer 120a (e.g., in the case of a pressure-sensitive adhesive, presses the stack of lenses 110 onto the windshield 10). Because the stack of lenses 110 is pre-shaped (pre-molded) (and optionally pre-trimmed) to fit the windshield 10, the customer need not be concerned with the process of shaping the lenses 110 and no specialized knowledge or equipment is required.

[0041] 1, which allows for illustrating both the formable enclosure 100 and also the formable stack 700 (or pre-formed stack after deformation), three lenses 110 are shown. However, the formable enclosure 100, the formable stack 700, or the pre-formed stack of lenses 110 may include a stack of four or more lenses 110, or a stack of two lenses 110, or even a stack of a single lens 110. That is, it is contemplated that the number of lenses 110 will depend on the particular application. Counterintuitively, the inventors have discovered that a stack of multiple lenses 110 is easier to thermoform onto a curved substrate 10 (or into a mold 40) than a stack having a single lens 110.

[0042] Throughout this disclosure, the term "transparent" is used broadly to encompass any material that can be seen through. The term "transparent" is not intended to exclude translucent, hazy, frosted, tinted, or pigmented materials.

[0043] The "coatings" described throughout this disclosure may be applied according to known methods such as spin coating, dip coating, vacuum deposition, and the like. The above description is provided by way of example, not limitation. Given the above disclosure, one skilled in the art will be able to devise variations that are within the scope and spirit of the invention disclosed herein. Furthermore, the various features of the embodiments disclosed herein can be used alone or in various combinations with each other and are not intended to be limited to the specific combinations described herein. Accordingly, the scope of the claims is not limited by the illustrated embodiments.

Claims

1. 1. A method for manufacturing a pre-formed stack of lenses that can be attached to a curved substrate, the method comprising: placing the moldable stack of lenses in a mold; producing the pre-formed stack of lenses from the formable stack of lenses by applying heat and pressure to the formable stack of lenses; removing the pre-formed stack of lenses from the mold; A method of providing

2. The method further comprises: deriving three-dimensional shape data from the curved substrate; forming the mold using the three-dimensional shape data; Equipped with The method of claim 1.

3. the step of deriving the three-dimensional shape data comprises optically scanning the curved substrate. The method of claim 2.

4. The curved substrate and the mold are the same type of windshield; The method of claim 1.

5. The mold has a compound curved surface. The method of claim 1.

6. applying the heat and the pressure comprises disposing a plurality of heaters on a frame positioned to direct the heaters toward the moldable stack of lenses; The method of claim 1.

7. applying the heat and the pressure comprises pressing the formable stack of lenses with one or more rollers; The method of claim 1.

8. the moldable stack of lenses further comprising a sacrificial layer disposed on an outermost lens of the moldable stack; the sacrificial layer comprises a sacrificial lens and a sacrificial adhesive; the sacrificial adhesive is interposed between the sacrificial lens and the outermost lens of the moldable stack; The method of claim 1.

9. the sacrificial layer is more heat resistant than the outermost lens of the moldable stack; The method of claim 8.

10. the sacrificial layer is less scratch resistant than the outermost lens of the moldable stack; 10. The method of claim 9.

11. the sacrificial layer is less scratch resistant than the outermost lens of the moldable stack; The method of claim 8.

12. the sacrificial lens comprises a biaxially stretched polyethylene terephthalate film; The method of claim 8.

13. The biaxially oriented polyethylene terephthalate film can withstand temperatures between room temperature and 220°C for 2 hours.

13. The method of claim 12.

14. the sacrificial lens comprises an opaque polyester film; The method of claim 8.

15. the outermost lens of the moldable stack comprises a transparent polyethylene terephthalate film; 15. The method of claim 14.

16. 1. A pre-formed stack of two or more lenses mountable to a curved substrate, said pre-formed stack comprising: a stack of two or more of said lenses; an adhesive layer interposed between each pair of adjacent lenses among the two or more lenses; It is equipped with the preformed stack having a compound curvature; Pre-formed stack.

17. each of the two or more lenses comprises a biaxially stretched polyethylene terephthalate film; 17. The preformed stack of claim 16.

18. 1. A method for manufacturing a pre-formed stack of one or more lenses that can be attached to a curved substrate, the method comprising: placing said moldable stack of one or more lenses onto a mold; applying heat and pressure to the formable stack of one or more of the lenses to produce the pre-formed stack of one or more of the lenses from the formable stack of one or more of the lenses; removing the pre-formed stack of one or more of the lenses from the mold; The method comprises:

19. The method further comprises: deriving three-dimensional shape data from the curved substrate; forming the mold using the three-dimensional shape data; Equipped with 20. The method of claim 18.

20. the step of deriving the three-dimensional shape data comprises optically scanning the curved substrate.

20. The method of claim 19.

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