Low electrostatic optically removable lens stack

Abstract

A removable lens stack includes a base layer comprising a substrate, an antistatic coating comprising quaternary ammonium cations and located on a first side of the substrate, and one or more removable lens layers stacked over the base layer. Each removable lens layer may include a substrate, an antistatic coating comprising quaternary ammonium cations and located on a first side of the substrate, and an adhesive located on a second side of the substrate opposite the first side. One or more removable lens layers may be stacked over the base layer such that the second side of the substrate of each removable lens layer faces the first side of the immediately preceding layer of substrate. The refractive indices of the substrate of the base layer, the substrate of each removable lens layer, and the adhesive of each removable lens layer may match (e.g., within 0.2).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is related to U.S. Provisional Application No. 63 / 377,155, filed on September 26, 2022, entitled “LOW STATIC OPTICAL REMOVABLE LENS STACK” and claims priority to the provisional application, the entire contents of which are expressly incorporated herein by reference.

[0003] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH / DEVELOPMENT

[0004] not applicable Background Art

[0005] Currently, optical removable lens stacks (such as those currently manufactured by Racing Optics, Inc. of Las Vegas, Nevada, the disclosure of which is expressly incorporated herein by reference) have become the industry standard for field of view and surface protection. One industrial area where such lens stacks have not been widely used is in sandblasting applications. Sandblasters wear protective helmets with rigid visors. The visors of the helmets wear very quickly, resulting in impaired field of view. Ideally, the helmet would incorporate the current removable lens stacks into the visor, and one layer of the stack would be removed when the field of view is impaired. However, it has been found that static electricity is generated when one layer of the stack is removed, and particles in the air will stick to the remaining lens stack surface and the visor. Each time an outer layer is removed from the lens stack, more static electricity is generated and released. In order for conventional lens stacks to be effectively used in sandblasting and other industrial and medical environments where static charge is undesirable, static electricity must be eliminated.

[0006] Static electricity is the name given to the accumulated charge on the surface of an insulator (a poor conductor of electricity). It is a surface phenomenon and occurs when two or more surfaces are brought into contact with each other and then separated. These charges are then released as each lens layer is removed. Polymers / plastics tend to have a negative charge. Air and skin tend to be positively charged. Surfaces of the same polarity repel each other. Surfaces of different polarities attract each other. This is why you feel a static shock when you separate two pieces of plastic from each other. The negative ions jump to the nearest positive ions in the air and on your skin. Summary of the invention

[0007] The present disclosure contemplates various systems and methods that can overcome the above-mentioned shortcomings associated with the prior art. One aspect of an embodiment of the present disclosure is a removable lens stack. The removable lens stack may include a base layer, the base layer including a substrate and an antistatic coating containing quaternary ammonium cations, the antistatic coating being disposed on a first side of the substrate. The removable lens stack may also include one or more removable lens layers stacked above the base layer, each removable lens layer including a substrate, an antistatic coating containing quaternary ammonium cations, and an adhesive, the antistatic coating being disposed on a first side of the substrate, and the adhesive being disposed on a second side of the substrate opposite to the first side. One or more removable lens layers may be stacked above the base layer so that the second side of the substrate of each removable lens layer faces the first side of the substrate of the base layer and the immediately preceding layer of the one or more removable lens layers. The refractive index of the substrate of the base layer, the substrate of each removable lens layer, and the adhesive of each removable lens layer may be matched to within 0.2.

[0008] Each removable lens layer may include an adhesion enhancement treatment portion between the substrate and the adhesive on the second side of the substrate. Each removable lens layer may be corona treated on the second side of the substrate. The base layer may include an adhesive disposed on a second side of the substrate opposite to the first side. The base layer may include an adhesion enhancement treatment portion between the substrate and the adhesive on the second side of the substrate. The base layer may be corona treated on the second side of the substrate. The base material of each removable lens layer may include a polyethylene terephthalate (PET) film or a thermoplastic polyurethane (TPU) film. The base material of the base layer may include a PET film or a TPU film.

[0009] Another aspect of the disclosed embodiments is a sandblasting helmet. The sandblasting helmet may include a face mask and one or more removable lens layers stacked on the face mask. Each removable lens layer may include a substrate, an antistatic coating containing quaternary ammonium cations, and an adhesive, the antistatic coating being disposed on a first side of the substrate, and the adhesive being disposed on a second side of the substrate opposite to the first side. One or more removable lens layers may be stacked on the face mask so that the second side of the substrate of the first removable lens layer in the one or more removable lens layers faces the face mask, and the second side of the substrate of each removable lens layer after the first removable lens layer faces the first side of the substrate of the immediately preceding removable lens layer in the one or more removable lens layers. The refractive index of the substrate of each removable lens layer may be matched to the refractive index of the adhesive of each removable lens layer (e.g., matched to within 0.2).

[0010] Each removable lens layer may include an adhesion enhancing treatment between the substrate and the adhesive on the second side of the substrate. Each removable lens layer may be corona treated on the second side of the substrate. The substrate of each removable lens layer may include a PET film or a TPU film.

[0011] Another aspect of the disclosed embodiments is a method for manufacturing a removable lens stack. The method may include providing an antistatic coating on a first substrate, the antistatic coating comprising quaternary ammonium cations. The method may also include providing an adhesive on a second substrate, and stacking the second substrate on the first substrate so that the adhesive disposed on the second substrate faces the antistatic coating disposed on the first substrate. The refractive indices of the first substrate, the second substrate, and the adhesive may be matched (e.g., matched to within 0.2).

[0012] The method may include providing an adhesion enhancing treatment on the second substrate prior to providing the adhesive. The method may include corona treating the second substrate prior to providing the adhesive. The first and / or second substrate may include a PET film or a TPU film. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] These and other features and advantages of the various embodiments disclosed herein may be better understood with reference to the following description and accompanying drawings, in which like reference numerals refer to like parts throughout, and in which:

[0014] Figure 1 A removable lens stack for a visor applied to a sandblasting helmet according to an embodiment of the present disclosure is shown;

[0015] Figure 2 is along Figure 1 A cross-sectional view of the removable lens stack and mask taken along line 2-2 in FIG.

[0016] Figure 3 is another cross-sectional view of the removable lens stack and the face mask with the outermost layer being peeled away from the removable lens stack; and

[0017] Figure 4 is an example operation flow according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0018] The present disclosure covers various embodiments of removable lens stacks that can be secured to a visor for a sandblasting helmet or that can be used as a visor for a sandblasting helmet, and methods of making and using the same. The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of several currently contemplated embodiments and is not intended to represent the only forms in which the disclosed invention may be developed or utilized. The present description sets forth functions and features in conjunction with the illustrated embodiments. However, it should be understood that the same or equivalent functions may also be achieved by different embodiments, which are also intended to be included within the scope of the present disclosure. It should also be understood that relational terms such as first and second, etc., are used solely to distinguish one entity from another and do not necessarily require or imply any such actual sequential relationship between such entities.

[0019] Figure 1A removable lens stack 100 is shown for a face shield 10 applied to a sandblasting helmet 20 according to an embodiment of the present disclosure, wherein: Figure 2 is a cross-sectional view thereof. The removable lens stack 100 may include a base layer 110 that may be secured (e.g., mechanically or with an adhesive) to a mask 10 or other surface, such as a visor lens or a visor or a transparent window of a helmet, shield, or gown, and the like, particularly those surfaces used in sandblasting or other activities that would benefit from avoiding static electricity buildup. Alternatively, the base layer 110 of the removable lens stack 100 may itself be used as a lens, visor, mask, or other surface, such as by attaching its periphery to the frame of a helmet, shield, gown, goggles, or other article. The removable lens stack 100 may also include one or more removable lens layers 120a, 120b, etc. (collectively 120) stacked above the base layer 110, each removable lens layer including: a substrate 122, such as a polyethylene terephthalate (PET) or thermoplastic polyurethane (TPU) film; and an adhesive 124 for bonding the removable lens layer 120 to the previously bonded lens layer 120 (or, in the case of the innermost removable lens layer 120, to the base layer 110). As debris accumulates on the outermost removable lens layer 120 during sandblasting or other activities, or as the layer 120 becomes concave or otherwise damaged, the wearer can simply tear it off, revealing the next new lens layer 120 (or base layer 110) underneath. Depending on the number of removable lens layers 120 in the stack, this process can be repeated several times before replacing the stack 100.

[0020] Figure 3 1 is another cross-sectional view of the removable lens stack 100 and the mask 10, wherein the outermost layer 120b of the removable lens stack 100 is being peeled off. In order to prevent static electricity accumulation that may otherwise be caused by peeling off each removable lens layer 120, each removable lens layer 120 may also include a Figure 2 and Figure 3 The antistatic coating 126 is shown. The antistatic coating 126 may include positively charged ions 30, for example, polyatomic ions such as quaternary ammonium cations (QAC), which may be dispersed in, for example, an acrylic or urethane polymer. By embedding the positive ions into the mating surfaces between the layers in this manner, static electricity caused by the separation of the negatively charged (usually plastic) lens 122 may be neutralized. Figure 3As shown, for example, the antistatic coating 126 of the removable lens layer 120a to be retained on the stack 100 is in direct contact with the removable adhesive 124 of the removable lens layer 120b being peeled off. The positive ions 30 embedded in the antistatic coating 126 attract the negative ions 40 released from the removable lens layer 120b when the layer 120 is peeled off. Although the negative ions 40 would normally create a net negative charge on the remaining removable lens layer 120a, thereby causing undesirable attraction of dust and debris from the air, in contrast, the negative ions 40 are attracted and neutralized by the positive ions 30 in the remaining removable lens layer 120a. In this way, when the layer 120 is removed from the stack 100, most, if not all, of the charge can be completely eliminated, thereby allowing for a static-free embodiment for sandblasting or other activities where static buildup is undesirable.

[0021] In addition to applying the antistatic coating 126, various other surface treatments may also be applied to the removable lens layer 120, typically in the form of a very thin coating that helps promote the effect on the surface of the lens layer 120. For particular uses in the context of the disclosed removable lens stack 100, each removable lens layer 120 may also include an adhesion enhancing treatment 128 between the substrate 122 and the adhesive 124. The adhesion enhancing treatment 128 may be, for example, a very thin (e.g., 5 to 10 nm) rough coat of acrylic or polyurethane. Alternatively, the substrate 122 may be corona treated to promote adhesion. By promoting adhesion of the substrate 122, it can be ensured that when a given layer (e.g., layer 120b) is removed from the underlying layer (e.g., layer 120a), the adhesive 124 remains with the substrate 122. Advantageously, this can prevent the transfer of undesirable residues to the next layer 120, which could impair the field of vision of the sandblaster or other wearers of the lens stack 100. Such clean removal typically results in increased static buildup, making the disclosed antistatic coating(s) 126 particularly beneficial where the removable lens layer 120 has been treated to enhance adhesion.

[0022] Similar to the removable lens layer 120, the base layer 110 of the removable lens stack 100 may include a substrate 112 and an antistatic coating 116, which may be the same as the substrate 122 and antistatic coating 126 of each removable lens layer 120. If the base layer 120 is to be secured to the mask 10 or other surface, the base layer 110 may also include an adhesive 114 (e.g., a self-wetting removable adhesive) and an optional adhesion enhancing treatment 118, which may be the same as the adhesive 124 and adhesion enhancing treatment 128 of each removable lens layer 120. In order to keep optical distortion as low as possible, the refractive indices of the substrates 112, 122 and any adhesives 114, 124 used can be matched (e.g., to within 0.2), as described in U.S. Patent No. 9,295,297, entitled "Adhesive Mountable Stack of Removable Layers," the entire contents of which are incorporated herein by reference.

[0023] Figure 4 is an example operation flow according to an embodiment of the present disclosure. Figure 4 The operation flow can be used as Figures 1 to 3An example method of manufacturing the removable lens stack 100 is described. The operational flow may begin by providing substrates 112, 122 to be used for the base layer 110 and each removable lens layer 120 (step 410). As previously described, substrates 112, 122 can be made of PET (e.g., biaxially oriented PET or BoPET) or TPU, and can be selected for specific modulation transfer function (MTF) data, or can be manufactured while actively monitoring MTF data in a continuous or batch process, as described in any of U.S. patent application publication No. 2021 / 0162645, entitled “Method and Apparatus for Reducing Non-Normal Incidence Distortion in Glazing Films,” U.S. patent application publication No. 2022 / 0032591, also entitled “Method and Apparatus for Reducing Non-Normal Incidence Distortion in Glazing Films,” or U.S. patent application publication No. 2021 / 0283994, entitled “Protective Barrier for Safety Glazing,” the entire contents of each of the above patent applications are incorporated herein by reference. In this regard, the step of providing the substrate 112, 122 may include, for example, melting a resin, extruding the molten resin through a die to form a film, and cooling the film. Specifically, examples of TPU films can be found in co-owned U.S. Patent Application No. 17 / 937,371, entitled "Multi-layer Windshield Film having Progressive Thickness Layers," the entire contents of which are incorporated herein by reference.

[0024] One side of each substrate 112, 122 may be coated with an antistatic coating 116, 126 (step 420). The antistatic coating 116, 126 may include an acrylic or urethane polymer having positively charged ions 30 dispersed therein, which may be applied to the substrate by, for example, spin coating, dip coating, or vacuum deposition. For example, the ions 30 may be the same as those found in consumer products such as dryer sheets or conditioners, but advantageously, the ions 30 may be dispersed in a very thin (e.g., 5 to 10 nm) optically transparent coating 116, 126 whose refractive index may be matched to that of the substrate 112, 122 (e.g., to within 0.2) to reduce optical distortion. On the opposite side, each removable lens layer substrate 122 (and optionally, the base layer substrate 112) may also be provided with an adhesion enhancing treatment 128, 118 (step 430), such as an acrylic or polyurethane rough coating or a corona treatment, and then coated with an adhesive 124, 114 (step 440), which is preferably wet deposited but may be applied according to any suitable method, including spin coating, dip coating, or vacuum deposition. The adhesive 114, 124 may be a wet mounting adhesive, such as disclosed in U.S. Patent Nos. 9,128,545, 9,274,625, and 10,620,670, all of which are entitled "Touch Screen Shield," the entire contents of each of which are incorporated herein by reference; or a dry mounting adhesive, such as disclosed in the aforementioned Patent No. 9,295,297. The adhesive 114 , 124 may be an acrylic or silicone adhesive, such as an acrylic pressure sensitive adhesive (PSA) or a silicone PSA, and in particular, may be an optically clear adhesive (OCA).

[0025] Figure 4The operational flow may continue by stacking one or more resulting lenses 120 on a base layer 110 to form a removable lens stack 100, the lens 120 comprising a substrate 122, an adhesive 124, an antistatic coating 126, and an optional adhesion enhancing treatment 128, the base layer 110 comprising a substrate 112 and an antistatic coating 116 (and in some cases, an adhesive 114 and an optional adhesion enhancing treatment 118) (step 450). An example stacking and adhesive curing process that may be used in conjunction with producing the removable lens stack 100 is described in co-owned U.S. patent application Ser. No. 17 / 823,413, entitled “Stack of Sterile Peelable Lenses with Low Creep,” the entire contents of which are incorporated herein by reference. If an adhesive 114 is used on the base layer 110, a release liner may be used to protect the adhesive 114 prior to applying the removable lens stack 100 to a mask or other article.In addition to the substrates 112, 122, adhesives 114, 124, antistatic coatings 116, 126, and adhesion enhancing treatments 118, 128 described herein, it is contemplated that the base layer 110 and / or each removable lens layer 120 may also include other layers or additives, such as the hard coating described in the above-mentioned U.S. Patent Application Publication No. 2021 / 0283994, the anti-reflective coating described in U.S. Patent Application Publication No. 2020 / 0124768, entitled “Transparent Covering Having Anti-Reflective Coatings”, the thermochromic film described in U.S. Patent Application Publication No. 2021 / 0070017, entitled “NanoParticle Solar Control Film”, and the thermochromic film described in U.S. Patent Application Publication No. 2021 / 0070017, both entitled “Low Haze UV ​​Blocking Removable Polymer Film”. The UV blocking layers or additives described in co-owned U.S. Patent Application Nos. 17 / 342,373 and 17 / 938,308, entitled “Low Reflectance Removable Lens Stack”, the moth-eye and / or fluoropolymer coatings described in U.S. Patent No. 11,307,329, entitled “Low Reflectance Removable Lens Stack”, and / or the coatings with different refractive indices described in U.S. Patent Nos. 10,427,385 and 11,141,959, both entitled “Low Reflectance Optical Web” and U.S. Patent Application Publication No. 2021 / 0402744, the entire contents of each of the above patents or patent applications are incorporated herein by reference. In order to keep optical distortion as low as possible, the refractive indices of the substrates 112, 122, adhesives 114, 124, antistatic coatings 116, 126, adhesion enhancing treatments 118, 128, and any other layers or additives within each layer 110, 120, and similarly, the refractive indices between the individual layers 110, 120 of the stack 100 can be matched (e.g., to within 0.2), as described in the aforementioned Patent No. 9,295,297.

[0026] exist Figure 2 and Figure 3In the example of , two removable lens layers 120 are shown stacked on the base layer 110 to form the removable lens stack 100. However, it is contemplated that there may be more than two (e.g., three, four, or more) removable lens layers 120, or there may be only a single removable lens layer 120. It should also be noted that not all removable lens layers 120 need to be identical. For example, the outermost removable lens layer 120 may not have an antistatic coating 126, because in the case of the outermost layer 120, the increased static charge accumulation caused by the previously removed layer 120 is no longer an issue. It is also contemplated that the thickness of the removable lens layer 120 may vary, for example, as described in the aforementioned U.S. Patent Application No. 17 / 937,371, or may have an easily torn off peripheral tab, the position of which may vary along the periphery of the layer 120. In this regard, an example system that can allow a removable lens stack 100 to be easily torn off when secured to a mask or other article is described in U.S. Patent Application Publication No. 2022 / 0304412, entitled “Tearoff Tab Tensioner,” the entire contents of which are incorporated herein by reference.

[0027] The above description is given by way of example and not limitation. Based on the above disclosure, those skilled in the art can design variations within the scope and spirit of the invention disclosed herein. In addition, the various features of the embodiments disclosed herein can be used alone or in different combinations from each other, and are not intended to be limited to the specific combinations described herein. Therefore, the scope of the claims is not limited by the illustrated embodiments.

Claims

1. A removable lens stack comprising: a substrate layer comprising a substrate and an antistatic coating comprising quaternary ammonium cations, the antistatic coating being disposed on a first side of the substrate; as well as one or more removable lens layers stacked over the base layer, each removable lens layer comprising a substrate, an antistatic coating comprising quaternary ammonium cations, and an adhesive, the antistatic coating being disposed on a first side of the substrate, and the adhesive being disposed on a second side of the substrate opposite to the first side, the one or more removable lens layers being stacked over the base layer such that the second side of the substrate of each removable lens layer faces the first side of the substrate of the base layer and an immediately preceding layer of the one or more removable lens layers, The refractive indices of the substrate of the base layer, the substrate of each removable lens layer, and the adhesive of each removable lens layer are matched to within 0.

2.

2. The removable lens stack of claim 1 , wherein: Each removable lens layer also includes an adhesion enhancing treatment between the substrate and the adhesive on a second side of the substrate.

3. The removable lens stack of claim 1 , wherein: Each removable lens layer is corona treated on the second side of the substrate.

4. The removable lens stack of claim 1 , wherein: The base layer also includes an adhesive disposed on a second side of the substrate opposite the first side.

5. The removable lens stack of claim 4, wherein: The base layer also includes an adhesion enhancing treatment between the substrate and the adhesive on a second side of the substrate.

6. The removable lens stack of claim 4, wherein: The base layer is corona treated on the second side of the substrate.

7. The removable lens stack of claim 1 , wherein: The substrate of each removable lens layer includes a polyethylene terephthalate (PET) film.

8. The removable lens stack of claim 1, wherein: The substrate of each removable lens layer includes a thermoplastic polyurethane (TPU) film.

9. The removable lens stack of claim 1, wherein: The base material of the base layer includes a polyethylene terephthalate (PET) film.

10. The removable lens stack of claim 1, wherein: The base material of the base layer includes a thermoplastic polyurethane (TPU) film.

11. A sandblasting helmet comprising: Face mask; as well as one or more removable lens layers stacked on the face mask, each removable lens layer comprising a substrate, an antistatic coating comprising quaternary ammonium cations, and an adhesive, the antistatic coating being disposed on a first side of the substrate, and the adhesive being disposed on a second side of the substrate opposite to the first side, the one or more removable lens layers being stacked on the face mask such that the second side of the substrate of a first removable lens layer of the one or more removable lens layers faces the face mask, and the second side of the substrate of each removable lens layer after the first removable lens layer faces the first side of the substrate of an immediately preceding removable lens layer of the one or more removable lens layers, The refractive index of the substrate of each removable lens layer is matched to the refractive index of the adhesive of each removable lens layer within 0.

2.

12. The sandblasting helmet according to claim 11, wherein: Each removable lens layer also includes an adhesion enhancing treatment between the substrate and the adhesive on a second side of the substrate.

13. The sandblasting helmet of claim 11, wherein: Each removable lens layer is corona treated on the second side of the substrate.

14. The sandblasting helmet of claim 11, wherein: The substrate of each removable lens layer includes a polyethylene terephthalate (PET) film.

15. The sandblasting helmet of claim 11, wherein: The substrate of each removable lens layer includes a thermoplastic polyurethane (TPU) film.

16. A method of manufacturing a removable lens stack, the method comprising: providing an antistatic coating on a first substrate, the antistatic coating comprising quaternary ammonium cations; providing an adhesive on a second substrate; stacking the second substrate on the first substrate so that the adhesive disposed on the second substrate faces the antistatic coating disposed on the first substrate, Wherein, the refractive indices of the first substrate, the second substrate and the adhesive are matched to within 0.

2.

17. The method of claim 16, further comprising providing an adhesion enhancing treatment on the second substrate prior to the step of providing the adhesive.

18. The method of claim 16, further comprising corona treating the second substrate prior to the step of providing the adhesive.

19. The method according to claim 16, wherein: The second substrate includes a polyethylene terephthalate (PET) film.

20. The method according to claim 16, wherein: The second substrate includes a thermoplastic polyurethane (TPU) film.

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