Sterilized peelable multi-lens stack with low creep - Patent Application 20070122999

Abstract

A method for producing a sterilized lens stack of peelable lenses comprises the steps of coating a first lens (or lens stack) with a first adhesive coating, heating the first adhesive coating to initiate curing, exposing the first adhesive coating to ultraviolet light to continue curing, laminating a second lens (or lens stack) onto the surface of the first adhesive coating to produce a lens stack, coating the second lens with a second adhesive coating, heating the second adhesive coating to initiate curing, exposing the second adhesive coating to ultraviolet light to continue curing, laminating a third lens (or lens stack) onto the surface of the second adhesive coating to add the third lens to the lens stack, and exposing the lens stack to an electron beam to continue curing of the first adhesive coating and the second adhesive coating.

Description

[Technical Field]

[0001] The present invention relates to a sterilized, peelable multi-lens stack having low creep. [Background technology]

[0002] Laminated, peelable, low peel strength (e.g., about 30-80 grams-inch) optical lens stacks can be used in a variety of situations, such as in connection with protective eyewear or vehicle windshields. The low peel strength allows each lens to be removed from the stack one at a time. (For example, when the peel strength increases above about 600 grams-inch, the bond can be considered permanent.) As each lens is added to create the laminate, the heat and UV exposure used to cure each successive layer of adhesive can also affect the already cured adhesive layers. For example, in a four-layer laminate, the first layer may be exposed to the curing process three or more times, while the last layer is exposed only once. This can result in an undercured layer that can lead to peel creep (i.e., increased peel strength) over time and at normal storage temperatures (e.g., 15°C to 30°C (59°F to 86°F)). Summary of the Invention [Problem to be solved by the invention]

[0003] The present disclosure contemplates various ways to overcome the above-mentioned shortcomings associated with the related art. [Means for solving the problem]

[0004] One aspect of an embodiment of the present disclosure is a method for producing a lens laminate consisting of multiple peelable lenses. The method may include the steps of: coating a first lens with a first adhesive coating (e.g., containing 30% or more solvent); a first heating step of heating the first adhesive coating to evaporate at least a portion of the solvent in the first adhesive coating and initiate curing of the first adhesive coating; and a first ultraviolet light exposure step of exposing the first adhesive coating to ultraviolet light to continue curing the first adhesive coating after the first heating step. The method may further include the step of laminating a second lens onto the surface of the first adhesive coating after the first ultraviolet light exposure step to produce a lens laminate. The method may further include a step of coating the second lens with a second adhesive coating (e.g., containing 30% or more solvent), a second heating step of heating the second adhesive coating to evaporate at least a portion of the solvent in the second adhesive coating and initiate curing of the second adhesive coating, and a second ultraviolet light exposure step of exposing the second adhesive coating to ultraviolet light after the second heating step to continue curing of the second adhesive coating.The method may further include a laminating step after the second ultraviolet light exposure step of laminating a third lens onto the surface of the second adhesive coating to add the third lens to the lens stack.The method may further include an electron beam exposure step after the laminating step of exposing the lens stack to an electron beam to continue curing of the first adhesive coating and the second adhesive coating.

[0005] The electron beam exposure step may be performed while the lens stack is on a roll-to-roll processing device. The temperature of the second heating step may be higher than the temperature of the first heating step. The exposure time of the second ultraviolet light exposure step may be longer than the exposure time of the first ultraviolet light exposure step. After the second heating step, the thickness of the first adhesive coating may be 20 μm or less, and the thickness of the second adhesive coating may be 20 μm or less. After the second heating step, the thickness variation of the first adhesive coating may be less than 0.5 μm over a 12 mm interval, and the thickness variation of the second adhesive coating may be less than 0.5 μm over a 12 mm interval. Each of the first lens, the second lens, and the third lens may comprise polyethylene terephthalate (PET). Each of the first adhesive coating and the second adhesive coating may comprise an optically clear adhesive (OCA). Each of the first adhesive coating and the second adhesive coating may comprise an acrylate.

[0006] The method may include an additional step after the laminating step and before the electron beam exposure step. The additional step may include a step of coating the third lens with a third adhesive coating (e.g., containing 30% or more solvent), a third heating step of heating the third adhesive coating to evaporate at least a portion of the solvent in the third adhesive coating and initiate curing of the third adhesive coating, and a third ultraviolet light exposure step of exposing the third adhesive coating to ultraviolet light after the third heating step to continue curing of the third adhesive coating. The additional step may further include a step of laminating a fourth lens onto the surface of the third adhesive coating after the third ultraviolet light exposure step to add the fourth lens to the lens stack. The electron beam exposure step may further continue curing of the third adhesive coating.

[0007] In some cases, the third lens and the fourth lens are already bonded together before the third lens is laminated onto the surface of the second adhesive. That is, two lens stacks consisting of two (or more) lenses may be combined together. In this regard, another aspect of an embodiment of the present disclosure is a method for producing a peelable lens stack, the method may include: coating a first lens with a first adhesive coating (e.g., containing 30% or more solvent); a first heating step of heating the first adhesive coating to evaporate at least a portion of the solvent in the first adhesive coating and initiate curing of the first adhesive coating; and a first ultraviolet light exposure step of exposing the first adhesive coating to ultraviolet light to continue curing of the first adhesive coating after the first heating step. The method may further include a step of laminating a second lens onto the surface of the first adhesive coating after the first ultraviolet light exposure step to produce a first lens stack. The method may further include a step of coating a third lens with a third adhesive coating (e.g., containing 30% or more solvent), a third heating step of heating the third adhesive coating to evaporate at least a portion of the solvent in the third adhesive coating and initiate curing of the third adhesive coating, and a third ultraviolet light exposure step of exposing the third adhesive coating to ultraviolet light to continue curing of the third adhesive coating after the third heating step. The method may further include a step of laminating a fourth lens onto the surface of the third adhesive coating to produce a second lens laminate after the third ultraviolet light exposure step.The method may further include a step of coating the second lens with a second adhesive coating (e.g., containing 30% or more solvent), a second heating step of heating the second adhesive coating to evaporate at least a portion of the solvent in the second adhesive coating and initiate curing of the second adhesive coating, and a second ultraviolet light exposure step of exposing the second adhesive coating to ultraviolet light after the second heating step to continue curing of the second adhesive coating. The method may further include a step of laminating the second lens stack onto the surface of the second adhesive coating after the second ultraviolet light exposure step to produce a combined lens stack from the first lens stack and the second lens stack. The method may further include an electron beam exposure step of exposing the combined lens stack to an electron beam to continue curing of the first adhesive coating, the second adhesive coating, and the third adhesive coating.

[0008] The electron beam exposure step may be performed while the assembled lens stack is on a roll-to-roll processing device. The temperature of the second heating step may be higher (e.g., by about 20%) than the temperature of the first heating step. The exposure time of the second ultraviolet light exposure step may be longer (e.g., by about 50%) than the exposure time of the first ultraviolet light exposure step. After the second heating step, the thickness of the first adhesive coating may be 20 μm or less, and the thickness of the second adhesive coating may be 20 μm or less. After the second heating step, the thickness variation of the first adhesive coating may be less than 0.5 μm over a 12 mm interval, and the thickness variation of the second adhesive coating may be less than 0.5 μm over a 12 mm interval, thereby reducing optical distortion. Each of the first lens, the second lens, the third lens, and the fourth lens may comprise polyethylene terephthalate (PET). Each of the first adhesive coating, the second adhesive coating, and the third adhesive coating may include an optically clear adhesive (OCA). Each of the first adhesive coating, the second adhesive coating, and the third adhesive coating may include an acrylate.

[0009] More generally, with respect to combining together a lens stack of two or more lenses, another aspect of an embodiment of the present disclosure may include a method of making a peelable lens stack, the method comprising a first production step of producing a first lens stack and a second production step of producing a second lens stack. The first production step may include providing a lens that will become the initial outermost lens in the first lens stack, and performing one or more of the following series of steps: coating the outermost lens in the first lens stack with an adhesive coating (e.g., containing 30% or more solvent), heating the adhesive coating to evaporate at least some solvent in the adhesive coating and initiate curing of the adhesive coating, exposing the adhesive coating to ultraviolet light to continue curing of the adhesive coating, and laminating an additional lens onto a surface of the adhesive coating, where the additional lens will in turn become the outermost lens in the first lens stack. Similarly, the second producing step may include providing a lens that will become the initial outermost lens in the second lens stack, and performing the following sequence of steps one or more times: coating the outermost lens in the second lens stack with an adhesive coating (e.g., containing 30% or more solvent); heating the adhesive coating to evaporate at least some of the solvent in the adhesive coating and initiate curing of the adhesive coating; exposing the adhesive coating to ultraviolet light to continue curing of the adhesive coating; and laminating an additional lens onto a surface of the adhesive coating, where the additional lens will now become the outermost lens in the second lens stack.The method may further include a step of coating the outermost lens of the first lens stack with an adhesive coating (e.g., containing 30% or more solvent), a heating step of heating the adhesive coating coated on the outermost lens of the first lens stack to evaporate at least a portion of the solvent in the adhesive coating and initiate curing of the adhesive coating, and an ultraviolet light exposure step of exposing the adhesive coating to ultraviolet light after the heating step to continue curing of the adhesive coating. The method may further include a step of laminating the second lens stack onto the surface of the adhesive coating after the ultraviolet light exposure step to combine the first lens stack and the second lens stack into a combined lens stack. The method may further include a step of exposing the combined lens stack to an electron beam to continue curing of the adhesive coating contained in the combined lens stack.

[0010] These and other features and advantages of the various embodiments disclosed herein may be better understood with regard to the following description and drawings. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 illustrates an example operational flow for manufacturing a stack of peelable lenses according to one embodiment of the present disclosure. [Figure 2] 2 illustrates an example sub-operational flow that may represent sub-steps of either or both of steps 110 and 120 in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure encompasses various embodiments of methods for manufacturing peelable multi-lens stacks, particularly stacks that may exhibit low peel creep. 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 deployed or utilized. The description describes functions and features in connection with the illustrated embodiments. It may be understood that the same or equivalent functions may be achieved by various embodiments that are, however, also intended to be encompassed within the scope of the present disclosure. It is further understood that relative terms such as "first" and "second" are used only to distinguish one entity from another entity and do not necessarily require or imply any actual relationship or order between such entities.

[0013] Figure 1 illustrates an example operational flow for manufacturing a lens laminate of multiple peelable lenses according to one embodiment of the present disclosure. Unlike conventional processes, the operational flow of Figure 1 includes a final step of exposing the lens laminate to an electron beam to crosslink all layers of the laminate and complete the curing process. As a result, under-cure can be avoided and peel creep can be significantly reduced. Advantageously, the electron beam exposure can simultaneously sterilize any microorganisms trapped between the laminated layers of the laminate, eliminating the need for subsequent radiation sterilization.

[0014] Peelable multi-lens laminates may function as or be attached to protective eyewear (e.g., goggles, glasses, or face masks) for off-road vehicle use or for surgical and other medical procedures. Display screens on mobile phones, personal computers, ATMs, and vending terminals may similarly use peelable multi-lens laminates to prevent damage to the underlying screen or to block side views (e.g., for privacy and security in public places). In other cases, peelable multi-lens laminates may function as or be attached to larger building windows or vehicle windshields for tinting (e.g., for privacy), thermal insulation, ultraviolet (UV) protection, or decoration. In any such setting, the outermost lens of the laminate may become soiled and obstruct the wearer's or operator's vision, allowing the outermost lens to be peeled off to reveal the next, fresh lens underneath. Examples of peelable multi-lens stacks that may be produced as described herein, and methods of production and installation that may be used with the processes described herein, include U.S. Pat. No. 8,361,260, entitled "Automobile having a Radiant Barrier," U.S. Pat. Nos. 9,128,545, 9,274,625, and 10,620,670, all entitled "Touch Screen Shield," and U.S. Pat. Nos. 9,295, 965, 975, 980, 995, 1000, and 1010, all entitled "Adhesive Mountable Stack of Removable Layers."No. 2020 / 0124768 entitled "Transparent Covering Having Anti-Reflective Coatings," U.S. Patent Application Publication No. 2020 / 0247102 entitled "Thermoform Windshield Stack with Integrated Formable Mold," U.S. Patent No. 11,364,715 entitled "Polymer Safety Glazing for Vehicles," U.S. Patent Application Publication No. 2021 / 0070017 entitled "Nano Particle Solar Control Film," and U.S. Patent Application Publication No. 2021 / 0070017 entitled "Method and Apparatus for Reducing Non-Normal Incidence Distortion in Glazing Films." Nos. 2021 / 0162645 and 2022 / 0032591, both entitled "Protective Barrier for Safety Glazing," 2021 / 0283994, entitled "Protective Barrier for Safety Glazing," 2022 / 0040956, entitled "Protective Barrier for Surfaces," 17 / 210,241, entitled "Tearoff Tab Tensioner," 17 / 342,373, entitled "Low Haze UV ​​Blocking Removable Lens Stack," and 17 / 342,373, entitled "Low Reflectance Removable Lens Stack," U.S. Patent No. 11,307, entitled "U ...329 and U.S. Pat. No. 10,427,385 entitled "Low Reflectance Optical Web," the entire contents of each of which are incorporated herein by reference.

[0015] 1 may begin with steps of producing first and second lenses, or first and second lens stacks of lenses (steps 110, 120). In the simplest case, producing only two stacks, steps 110 and 120 may, for example, each produce only one lens, which may then be combined according to steps 130-170. When producing a lens stack of three or more lenses, one or both of steps 110 and 120 may itself produce a lens stack of lenses (which may be a sub-stack of the final lens stack produced by steps 130-170).

[0016] As an example, a lens stack consisting of three lenses may be produced according to the operational flow of FIG. 1 as follows. The operational flow may begin with producing a first lens stack consisting of two lenses (step 110). For example, referring to the sub-operational flow of FIG. 2, step 110 begins with providing a first lens (step 210), such as a polyethylene terephthalate (PET) lens or other optically clear substrate, which may be provided as a web for roll-to-roll processing. The first lens may be, for example, 25 μm-400 μm thick. The first lens may be coated with a first adhesive coating (step 220), including a laminating adhesive, such as an optically clear adhesive (OCA), which may be a pressure-sensitive adhesive (PSA) type. To meet the criteria of high transmission, low haze, and low distortion, a very thin coating of laminating adhesive, on the order of 10-20 μm (or even 5-20 μm), may be preferred, especially considering that optical errors such as haze and distortion are added with each additional layer in the laminate. To this end, the adhesive coating may contain a high solvent to solids content, e.g., 30% or more. To produce a thin PSA, for example, 30%-60% solvent may be mixed with the acrylate to reduce the viscosity of the liquid, which may then be placed onto the first lens via gravure, rod, or slot die in a roll-to-roll process. The surface of the first lens may be nano-roughened to promote high peel strength of the PSA, so that the PSA remains permanently attached to the first lens surface when the first lens is peeled from the next laminated lens.

[0017] The coated first lens may then go through several curing stages. For example, as shown in FIG. 2, the adhesive coating is first heated (e.g., by one or more ovens at approximately 150-220°F) to evaporate at least a portion of the solvent (step 230). This can reduce the thickness by 40%-70%, flattening the coating to a consistent thickness and minimizing optical distortion. After heating (or after subsequent heating steps, when the effect is cumulative), for example, the adhesive coating may have a thickness of 20 μm or less (e.g., 5 μm-20 μm), with a thickness variation of less than 0.5 μm over a 12 mm interval across the web. Heating may also initiate curing of the first adhesive coating, at which point some crosslinking may begin to occur. The adhesive coating may then be exposed to ultraviolet (UV) light (e.g., 0.1 Mj / m 2 -1.0Mj / m 2 ) to begin photoinitiation of the cross-linking process (step 240).

[0018] With the first adhesive coating in this partially cured state, the operational flow may proceed to laminating an additional lens onto the surface of the partially cured adhesive coating, for example by a nipping roller (step 250). At this stage, the sub-process of Figure 2 has produced a two-lens lens stack that can function as the first lens stack produced by step 110 of Figure 1.

[0019] The operational flow of FIG. 1 may then proceed to producing a second lens or stack (step 120), which may be simply a single lens in the case of producing a three-layer stack. In this regard, the operational flow of FIG. 2 may begin again at this point, this time as a sub-process of step 120. Because only a single lens is produced in this step, steps 220-250 may be omitted, and the lens may simply be provided in step 210. Thus, in a relatively simple example of a three-layer stack, a two-layer stack may be produced by step 110, while a single lens is produced by step 120. The operational flow of FIG. 1 may then proceed to covering the outermost lens in the first lens stack (produced by step 110) with an adhesive coating (step 130). In this case, the outermost lens in the first lens stack may be an additional lens laminated onto the first lens in step 250 during the sub-operational flow of step 110. The adhesive coating (second adhesive coating) may be the same as that described above and may also be heated (step 140) and exposed to UV light (step 150). A third lens may be added to the lens stack by laminating one lens produced by step 120 onto the surface of the partially cured second adhesive coating, for example, by a nipping roller (step 160).

[0020] Unlike conventional processes for manufacturing peelable multi-lens laminates, the operational flow of FIG. 1 may conclude with step 170, in which the entire assembled lens laminate is exposed to an electron beam to continue curing the adhesive coatings contained therein (i.e., the first and second adhesive coatings in the example of a three-layer laminate). The electron beam exposure may preferably be performed while the lens laminate is still on the roll-to-roll processing equipment used to assemble it. Advantageously, the electron beam exposure can complete the curing function equally in all layers of the laminate. Because the laminate is relatively thin (e.g., about 0.254 mm–0.635 mm (10–25 mils)), the electron beam exposure can be very uniform from top to bottom of the laminate. If a UV-absorbing compound is present in the adhesive coating (e.g., to improve weatherability), the electron beam may still provide a uniform exposure, unlike that seen with UV exposure processes in the presence of a UV-absorbing compound.

[0021] It will be appreciated that the processing time for each adhesive layer may vary, as each additional layer experiences fewer heating and UV processes than the previous layer. As discussed above, electron beam curing can help achieve uniform curing between layers by completing the curing function for the entire stack. It is also contemplated that varying the curing process throughout the operational flow of FIG. 1 can further enhance uniformity of curing. For example, the temperature of a later heating process (e.g., step 140) may be higher than the temperature of an earlier heating process (e.g., step 230). That is, using the three-layer stack described above as an example, the heating temperature of the second adhesive coating may be higher than the heating temperature of the first adhesive coating. Alternatively, or in addition, the exposure time of a later UV exposure process (e.g., step 150) may be longer than the exposure time of an earlier UV exposure process (e.g., step 240). For example, continuing with the three-layer example described above, the exposure time of the second adhesive coating to UV light may be longer than the exposure time of the first adhesive coating to UV light. In this way, the higher temperatures and / or longer UV exposure experienced by subsequent adhesive coatings can help them "catch up" with the cure of earlier adhesive coatings that have already received some heating and / or UV exposure. By modifying the thermal and UV cure at each layer, a more uniform partial cure can be achieved before the entire stack is exposed to the electron beam for a final cure (step 170) to more accurately meet the target peel strength at each layer of the stack.

[0022] Similarly, and generally, the thermal and UV curing times and other parameters may be selected with the subsequent electron beam curing in mind. In particular, the thermal and UV curing may be less than in conventional manufacturing processes so that the electron beam curing does not over-harden the laminate and excessively increase the peel strength. Generally, the electron beam curing may adjust the peel strength of the adhesive coating toward the target peel strength, and the earlier thermal and UV curing are therefore only intended to initiate the curing process, not to reach the target peel strength.

[0023] As a further consequence of exposing the lens laminate to an electron beam while it is still in the roll-to-roll process, the electron beam exposure can also provide sterilization of any microorganisms trapped between the laminated layers of the laminate, thus ensuring a sterile lens laminate. This significantly increases the efficiency of the manufacturing process compared to, for example, first cutting the desired shapes (e.g., eyewear lens shapes) from a roll and then shipping them to a laboratory for gamma sterilization of the interlayers. In this regard, it should be noted that electron beam exposure typically cannot be used for this type of downstream sterilization because it is unclear whether peel strength would be affected by further crosslinking of the adhesive.

[0024] In the above example, a lens stack of three lenses is produced according to the operational flow of Figure 1, with step 110 producing a sub-laminate of two lenses (by performing steps 210-250) and step 120 producing one lens (by performing only step 210). If a lens stack of four lenses, five lenses, or more lenses is desired, the operational flow of Figure 1 is performed in substantially the same manner, while steps 220-250 are repeated as desired during step 110, with each new adhesive coating being applied to each additional lens in succession. Thus, for example, a lens stack of four lenses may be produced according to the operational flow of Figure 1 as follows: First, a lens stack consisting of three lenses is produced (step 110), i.e., referring to the sub-operation flow of FIG. 2, the steps include providing a first lens (step 210), coating the first lens with a first adhesive coating (step 220), heating the first adhesive coating to evaporate at least a portion of its solvent (step 230), exposing the first adhesive coating to UV light to continue curing the first adhesive coating (step 240), and attaching a second lens to the first adhesive coating. laminating a second lens onto the surface of the first adhesive coating (step 250); coating a second lens with a second adhesive coating (step 220 again); heating the second adhesive coating to evaporate at least a portion of its solvent (step 230 again); exposing the second adhesive coating to UV light to continue curing the second adhesive coating (step 240 again); and laminating a third lens onto the surface of the first adhesive coating (step 250 again).1 may then proceed to producing a single lens as described above (step 120, which consists solely of a subprocess of step 210), or may continue with coating the outermost lens in the first lens stack (produced by step 110) with a third adhesive coating (step 130), heating and exposing the third adhesive coating to UV light (steps 140 and 150), adding a fourth lens to the lens stack by laminating the single lens produced by step 120 onto the surface of the partially cured third adhesive coating (step 160), and finally exposing the combined lens stack to an electron beam (step 170). Larger stacks can be produced by simply repeating steps 220-250 additional times during step 110.

[0025] A lens stack may be created by combining two sub-stacks (e.g., a 2x2 stack, a 2x3 stack, etc.) each consisting of two or more lenses. To illustrate this, another approach to creating a lens stack of four lenses according to the operational flow of FIG. 1 is as follows. First, referring to the sub-operational flow of FIG. 2, a stack of two lenses may be created (step 110) by performing steps 210-250 once without repeating steps 220-250. Then, a second stack of two lenses may be created in exactly the same way, i.e., by performing steps 210-250 once without repeating steps 220-250 (step 120). 1 may then continue with coating the outermost lens of the first two-lens sub-laminate (produced by step 110) with an adhesive coating (step 130), heating the adhesive coating and exposing it to UV light (steps 140 and 150), laminating the second two-lens sub-laminate (produced by step 120) onto the surface of the partially cured adhesive coating to combine the two sub-laminates into a four-lens lens stack (step 160), and finally exposing the combined lens stack to an electron beam (step 170). Larger stacks of this type can be easily produced by repeating steps 220-250 additional times during either or both steps 110 and 120.

[0026] If one or both of steps 110 and 120 include repetitions of steps 220-250 of FIG. 2, each successive repetition of the heating and UV exposure processes (steps 230 and 240) can have different parameters to achieve a more uniform partial cure, as described above. Thus, for example, step 230 in earlier repetitions can have a lower temperature, step 230 in later repetitions can have a higher temperature, and the final heating step in step 140 can be at the highest temperature. Similarly, step 240 in earlier repetitions can have a shorter UV exposure time, step 240 in later repetitions can have a longer UV exposure time, and the final UV exposure in step 150 can have the longest UV exposure time. In this way, a more uniform partial cure can be achieved before the entire stack is exposed to the electron beam for final cure (step 170) to more accurately meet the target peel strength for each layer of the stack.

[0027] Generally, however, any of the above processes and subprocesses can be repeated until the desired number of lenses have been laminated into the peelable laminate. In some cases, sublaminates can be combined to form a laminate, or the laminates themselves can be sublaminates that can be combined into a larger laminate. For example, one possible process is to combine two laminates of two lenses each, and then combine the resulting four-lens laminate with another four-lens laminate to produce a single eight-lens laminate. The resulting combined laminate can then be exposed to an electron beam (step 170) to complete the curing process for all adhesive coatings contained therein.

[0028] The above description is provided by way of example, not limitation. Given the above disclosure, those 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 varying combinations with each other and are not intended to be limited to the specific combinations described herein. Therefore, the scope of the claims should not be limited by the embodiments shown.

Claims

1. A method for producing a lens stack consisting of a plurality of peelable lenses, comprising: coating a first lens with a first adhesive coating; a first heating step of heating the first adhesive coating to evaporate at least a portion of the solvent in the first adhesive coating and to initiate curing of the first adhesive coating; a first ultraviolet light exposure step after the first heating step of exposing the first adhesive coating to ultraviolet light to continue curing of the first adhesive coating; laminating a second lens onto the surface of the first adhesive coating after the first ultraviolet light exposure step to produce a lens stack; coating the second lens with a second adhesive coating; a second heating step of heating the second adhesive coating to evaporate at least a portion of the solvent in the second adhesive coating and to initiate curing of the second adhesive coating; a second ultraviolet light exposure step after the second heating step of exposing the second adhesive coating to ultraviolet light to continue curing of the second adhesive coating; a laminating step after the second ultraviolet light exposure step, of laminating a third lens onto the surface of the second adhesive coating to add the third lens to the lens stack; and an electron beam exposure step after the laminating step of exposing the lens stack to an electron beam to continue curing of the first adhesive coating and the second adhesive coating.

2. The method of claim 1 , wherein the electron beam exposure step is performed while the lens stack is on a roll-to-roll processing tool.

3. The method of claim 1 , wherein the temperature of the second heating step is higher than the temperature of the first heating step.

4. 2. The method of claim 1, wherein the exposure time of the second ultraviolet light exposure step is longer than the exposure time of the first ultraviolet light exposure step.

5. 10. The method of claim 1, wherein after the second heating step, the first adhesive coating has a thickness of 20 μm or less and the second adhesive coating has a thickness of 20 μm or less.

6. 10. The method of claim 1, wherein after the second heating step, the first adhesive coating has a thickness variation of less than 0.5 μm over a 12 mm interval and the second adhesive coating has a thickness variation of less than 0.5 μm over a 12 mm interval.

7. The method of claim 1 , wherein the first lens, the second lens, and the third lens each comprise polyethylene terephthalate (PET).

8. The method of claim 1 , wherein the first adhesive coating and the second adhesive coating each comprise an optically clear adhesive (OCA).

9. The method of claim 1 , wherein the first adhesive coating and the second adhesive coating each comprise an acrylate.

10. The method further comprises, after the laminating step and before the electron beam exposing step, coating the third lens with a third adhesive coating; a third heating step of heating the third adhesive coating to evaporate at least a portion of the solvent in the third adhesive coating and to initiate curing of the third adhesive coating; a third ultraviolet light exposure step after the third heating step of exposing the third adhesive coating to ultraviolet light to continue curing of the third adhesive coating; after the third ultraviolet light exposure step, laminating a fourth lens onto the surface of the third adhesive coating to add the fourth lens to the lens stack; The method of claim 1 , wherein the electron beam exposure step further continues the curing of the third adhesive coating.

11. A method for producing a lens stack consisting of a plurality of peelable lenses, comprising: coating a first lens with a first adhesive coating; a first heating step of heating the first adhesive coating to evaporate at least a portion of the solvent in the first adhesive coating and to initiate curing of the first adhesive coating; a first ultraviolet light exposure step after the first heating step of exposing the first adhesive coating to ultraviolet light to continue curing of the first adhesive coating; laminating a second lens onto the surface of the first adhesive coating after the first ultraviolet light exposure step to produce a first lens stack; coating the third lens with a third adhesive coating; a third heating step of heating the third adhesive coating to evaporate at least a portion of the solvent in the third adhesive coating and to initiate curing of the third adhesive coating; a third ultraviolet light exposure step after the third heating step of exposing the third adhesive coating to ultraviolet light to continue curing of the third adhesive coating; laminating a fourth lens onto the surface of the third adhesive coating after the third ultraviolet light exposure step to produce a second lens stack; coating the second lens with a second adhesive coating; a second heating step of heating the second adhesive coating to evaporate at least a portion of the solvent in the second adhesive coating and to initiate curing of the second adhesive coating; a second ultraviolet light exposure step after the second heating step of exposing the second adhesive coating to ultraviolet light to continue curing of the second adhesive coating; laminating the second lens stack onto the surface of the second adhesive coating after the second ultraviolet light exposure step to create a combined lens stack from the first lens stack and the second lens stack; exposing the assembled lens stack to an electron beam to continue curing the first adhesive coating, the second adhesive coating, and the third adhesive coating.

12. The method of claim 11 , wherein the electron beam exposure step is performed while the assembled lens stack is on a roll-to-roll processing tool.

13. 12. The method of claim 11, wherein the temperature of the second heating step is higher than the temperature of the first heating step.

14. 12. The method of claim 11, wherein the exposure time of the second ultraviolet light exposure step is longer than the exposure time of the first ultraviolet light exposure step.

15. 12. The method of claim 11, wherein after the second heating step, the first adhesive coating has a thickness of 20 μm or less and the second adhesive coating has a thickness of 20 μm or less.

16. 12. The method of claim 11, wherein after the second heating step, the first adhesive coating has a thickness variation of less than 0.5 μm over a 12 mm interval and the second adhesive coating has a thickness variation of less than 0.5 μm over a 12 mm interval.

17. 12. The method of claim 11, wherein each of the first lens, the second lens, the third lens, and the fourth lens comprises polyethylene terephthalate (PET).

18. The method of claim 11 , wherein the first adhesive coating, the second adhesive coating, and the third adhesive coating each comprise an optically clear adhesive (OCA).

19. The method of claim 11 , wherein the first adhesive coating, the second adhesive coating, and the third adhesive coating each comprise an acrylate.

20. A method for producing a lens stack consisting of a plurality of peelable lenses, comprising: A first production step of producing a first lens laminate, providing a lens that will be the initial outermost lens in the first lens stack; carrying out the following sequence of steps one or more times: coating the outermost lens in the first lens stack with an adhesive coating; heating the adhesive coating to evaporate at least a portion of the solvent in the adhesive coating and to initiate curing of the adhesive coating; exposing the adhesive coating to ultraviolet light to continue curing the adhesive coating; and a first producing step including: laminating an additional lens onto a surface of the adhesive coating, the additional lens then becoming the outermost lens in the first lens stack, the first producing step being performed one or more times; A second production step of producing a second lens laminate, providing a lens that will be the first outermost lens in the second lens stack; carrying out the following sequence of steps one or more times: coating the outermost lens in the second lens stack with an adhesive coating; heating the adhesive coating to evaporate at least a portion of the solvent in the adhesive coating and to initiate curing of the adhesive coating; exposing the adhesive coating to ultraviolet light to continue curing the adhesive coating; and a second producing step including performing one or more steps of laminating an additional lens onto the surface of the adhesive coating, the additional lens then becoming the outermost lens in the second lens stack; coating the outermost lens in the first lens stack with an adhesive coating; a heating step of heating the adhesive coating coated on the outermost lens of the first lens stack to evaporate at least a portion of the solvent in the adhesive coating and to initiate curing of the adhesive coating; an ultraviolet light exposure step after the heating step of exposing the adhesive coating to ultraviolet light to continue curing of the adhesive coating; laminating the second lens stack onto the surface of the adhesive coating after the ultraviolet light exposure step to combine the first lens stack and the second lens stack into a combined lens stack; exposing the assembled lens stack to an electron beam to continue curing of the adhesive coating contained within the assembled lens stack.

21. A method for producing a lens stack consisting of a plurality of peelable lenses, comprising: providing a lens stack having an adhesive coating disposed between each pair of adjacent lenses in the lens stack; exposing the lens stack to an electron beam to adjust the peel strength of the adhesive coating towards a target peel strength and simultaneously sterilize the lens stack.

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