Temporary Polarizing Patch

Abstract

To provide an inexpensive, but attractive approach for easily changing spectacles into polarization sunglasses.SOLUTION: A flexible polarization patch is formed using an optical polymer sheet which has a light delay, an elastic modulus, and a Shore A hardness within specific ranges. The polarization patch conforms to shapes of non-polarization lens varying in power, and provides polarization efficiency corresponding to ordinary polarization lenses.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the field of spectacle lenses and polarizing laminates for spectacle lenses. [Background technology]

[0002] Sun and glare protection options are limited for individuals who wear prescription eyeglasses. Prescription sunglasses are typically more expensive than prescription eyeglasses and require the eyeglass wearer to carry a second pair of glasses. Although photochromic lenses darken in sunlight, these lenses do not offer the anti-glare features of polarized lenses. Clip-on sunglasses provide a removable sun cover for eyeglasses, but this option may be considered unattractive to many consumers. Summary of the Invention [Problem to be solved by the invention]

[0003] Lens and sunglass manufacturers have produced frameless sunshade films that are attached to the surface of eyeglass lenses. US 2014 / 0232978 discloses optical elements that are reversibly bonded to an optical lens. These elements require a pressure sensitive adhesive to bond the elements to the optical lens. The adhesive can leave a residue on the lens that attracts dust and other particulates even after it is removed. Furthermore, the adhesion of the elements gradually weakens with each repeated application and removal. US 2014 / 0118681 discloses a process for making temporary photochromic patches for eyeglass lenses. The patches can be temporarily affixed to eyeglass lenses without the need for adhesives. However, the process of mixing polydimethylsiloxane and photochromic dyes cannot be used to make polarized patches. US Patent No. 5,764,333 discloses a method for making sunshades for sunglasses. The method includes cutting a single layer plastic film into the shape of an eyeglass lens. The materials available for manufacturing the single layer plastic film are limited, and plastic film optical retardation is not disclosed.

[0004] Despite advances in the field of converting eyeglasses to polarized sunglasses, currently available options have many shortcomings. There is a need for an inexpensive yet attractive approach to easily convert eyeglasses to polarized sunglasses. [Means for solving the problem]

[0005] Disclosed herein is an optical polymer sheet having a specific range of optical retardation, modulus, and Shore A hardness. The optical polymer sheet contains a polarizing component and can be removably attached to a non-polarized lens to provide a polarizing function. The polarizing patch is flexible and can conform to the shape of various prescription eyeglass lenses, providing polarization performance equivalent to conventional polarized lenses. The flexible polarizing patch can be pre-cut to the shape of the lens or can be cut by the consumer and can be applied to non-polarized eyeglasses to temporarily convert them into polarized eyewear.

[0006] The polarizing patch disclosed herein converts prescription glasses into polarized glasses, providing the same polarizing function as regular polarized sunglasses. The polarizing patch has the same polarization efficiency as regular sunglasses, and about the same anti-glare effect. In some embodiments, the polarizing patch is formed by sandwiching a polyvinyl alcohol (PVA) polarizing film between two transparent polymer sheets. In some aspects, the polarizing film is aligned perpendicular to the polarization axis and horizontally to the absorption axis. The PVA polarizing film performs the anti-glare function. Since glare is typically horizontally polarized, i.e. perpendicular to the polarization axis of the film, most of the glare is absorbed, while light polarized parallel to the polarization axis is transmitted.

[0007] The objective of the present disclosure is to provide a removable polarizing laminate that reduces the transmission of light to non-polarized optics. The polarizing laminate provides the wearer with polarization and anti-glare features not found in photochromic lenses. The polarizing laminate does not require adhesives for attachment to eyeglass lenses. The laminate materials, particularly the front side, are selected to avoid optical retardation that would change the polarization state of the incident glare. In some aspects, the front layer of the polarizing patch laminate is selected to minimize or avoid optical retardation. In some embodiments, the patch includes the use of a polarizing laminate consisting of a polarizing film bonded between two flexible polymeric sheets. The laminate is cut to the shape of an eyeglass lens and applied to the eyeglass to provide the polarization function. The laminate may be made of a polymeric material with minimal optical retardation, a modulus within a certain range, and a Shore A hardness below a certain value to form a polarizing patch that can conform to the shape of lenses with various powers.

[0008] In some embodiments, the patch that reduces the transmission of light to a non-polarizing optical component is made of a flat flexible laminate that includes at least one polarizing film. The patch is releasably securable to the non-polarizing optical component and can be secured to the optical component using a pressure sensitive adhesive (PSA) or electrostatic adhesion. In embodiments that use a pressure sensitive adhesive, the pressure sensitive adhesive is placed on the side of the patch that contacts the lens. In some embodiments, the patch is applied to the lens using water or soapy water.

[0009] In some embodiments, the polarizing film includes a polarizing film sheet laminated between a first transparent front polymer sheet and a second transparent back polymer sheet in contact with the lens. The polarizing film sheet may be a polyvinyl alcohol (PVA) sheet, a PVA-based sheet, polyester (PET), PVA-PVE (polyvinylene), wire grid, a multilayer reflective polarizing sheet (e.g., 3M Vikuiti™ DBEF (dual brightness enhancement film)), or other polarizing film sheets known in the industry. The laminate may include at least one adhesive and / or at least one primer between the layers to bond the layers together. The adhesive and / or primer may be selected from adhesives and primers used in the field of laminates. The first and second transparent polymer sheets may be individually selected from polyvinyl chloride (PVC), thermoplastic polyurethane (TPU), polydimethylsiloxane (PDMS), polyester, or thermoplastic elastomer (TPE). In some embodiments, the optical retardation of the transparent front polymeric sheet is π / 5 radians or less, preferably π / 10 radians or less. In some embodiments, the elastic modulus of the patch is 700 Mpa or less. In some aspects, the thickness of the patch is 200 μm or less. In additional embodiments, the Shore A hardness of the patch is 80 or less. In some aspects, the elastic modulus, thickness, and Shore A hardness are selected to provide flexibility to the patch to allow for releasable attachment to a variety of non-polarizing optical component shapes.

[0010] In some aspects, the patch reduces the transmission of non-perpendicularly polarized light. In some embodiments, the patch is the same size and shape as the non-polarizing optic to which it is releasably securable. In some embodiments, the patch can be manufactured or cut by a manufacturer to the same size and shape as the optic. In other embodiments, the patch can be cut by a user to the same size and shape as the optic. In some embodiments, the patch is not the same size and shape as the non-polarizing optic to which it is releasably securable. In some embodiments, the patch has a nominal magnification.

[0011] Shore A hardness is measured with an instrument known as a durometer, and is therefore also known as "durometer hardness." The hardness value is measured by the penetration of the durometer's indenter foot into the sample. Because the rebound forces of rubber and plastics can cause the indentation reading to change over time, the indentation time is sometimes reported along with the hardness number. The ASTM test method standard is ASTM D2240 00, with related methods including ISO 7619 and ISO 868; DIN 53505; and JIS K 6301, which has been discontinued and replaced by JIS K 6253.

[0012] Any embodiment of the disclosed compositions and / or methods may consist of or consist essentially of any of the described elements and / or features and / or steps rather than including / containing / having any of them. Thus, in any claim, any of the open-ended linking verbs listed above may be substituted with the terms "consisting of" or "consisting essentially of" in order to modify the scope of a given claim from that which would be the case if the open-ended linking verb were used.

[0013] The term "substantially" and variations thereof are defined as generally, but not necessarily completely, understood by those of skill in the art, and in one non-limiting embodiment, "substantially" refers to within 10%, within 5%, within 1%, or within 0.5%.

[0014] The terms "about" or "approximately" or "substantially unchanged" are defined as close to the degree that would be understood by one of ordinary skill in the art, and in one non-limiting embodiment, these terms are defined as within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0015] The articles "a" or "an" when used in conjunction with the term "comprising" in the claims and / or this specification may mean "one," but are also consistent with the meanings of "one or more," "at least one," and "one or more."

[0016] As used in the specification and claims, the words "comprising" (and any form of including, such as "include" or "includes"), "having" (and any form of having, such as "having" or "comprising"), "containing" (and any form of including, such as "containing" or "embracing"), or "containing" (any form of containing, such as "containing" or "incorporating") are open ended and do not exclude additional, unrecited elements or method steps.

[0017] The compositions and methods of use thereof can "comprise," "consist essentially of," or "consist of" any element or step disclosed throughout this specification. In one non-limiting aspect, with respect to the transitional phrase "consisting essentially of," a basic and novel feature of the compositions and methods disclosed herein involves the ability of the patches to provide polarizing functionality to prescription lenses.

[0018] Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the following detailed description and examples, while indicating specific embodiments of the present invention, are given for illustrative purposes only. It is also believed that modifications and variations within the spirit and scope of the present invention will become apparent to those skilled in the art from the following detailed description. [Brief description of the drawings]

[0019] [Figure 1] 1 shows one embodiment of a polarized patch laminate. The laminate includes a polarized PVA layer covered by a PVC layer on either side. An adhesive is used to bond the layers of the laminate together. [Diagram 2] 1 shows a horizontal cross-sectional view of a TPU / PVA / TPU polarized patch embodiment, in which the patch laminate layers, from top to bottom, include a TPU layer, a layer of pressure sensitive adhesive, a polarized PVA layer, a layer of pressure sensitive adhesive, and a TPU layer. [Figure 3A] 1 shows a patch sample prepared for adhesion testing: PET film with low tack adhesive on one side and high tack adhesive on the other side. [Figure 3B]1 shows patch samples prepared for adhesion testing, and elliptical patches cut from a film of a polarizing laminate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Various features and advantageous details will be more fully described with respect to the non-limiting embodiments illustrated in the accompanying drawings and detailed below. It should be understood, however, that the detailed description and specific examples, while illustrating embodiments, are for illustrative purposes only and are not intended to limit the invention. Various substitutions, modifications, additions and / or rearrangements will become apparent to those skilled in the art from this disclosure.

[0021] In the following description, numerous specific details are provided to provide a thorough understanding of the disclosed embodiments. However, one of ordinary skill in the art will recognize that the present invention can be practiced without one or more of the specific details, or without other methods, elements, materials, etc. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the present invention.

[0022] The presently disclosed polarizing patch can be applied to optical lenses with or without adhesive to provide polarization performance comparable to that of conventional sunglasses. In order for the polarizing patch to provide polarization efficiency comparable to that of regular polarized sunglasses, the polymer sheet, particularly the front side, is selected to avoid optical retardation that would change the polarization state of the incident glare. If optical retardation is present in the front polymer sheet, the polarizing patch will not be able to effectively block the horizontal glare that is typically blocked by regular polarized sunglasses.

[0023] The polarizing patches disclosed herein are flexible enough to conform to the shapes of lenses of various powers, typically from approximately 0 to 8 degrees or more. Again, selection of an outer polymeric sheet with the proper modulus of elasticity is important to create a polarizing patch with adequate flexibility.

[0024] Although not required, it is preferred that the polarizing patch can be attached to an existing eyeglass lens without the use of adhesive. There is a need for a polarizing patch that can conform to the surface contour of the lens while being subject to electrostatic adhesion. Therefore, it is highly advantageous to select a back polymer sheet with an appropriate hardness. In other embodiments, an adhesive may be used to attach the polarizing patch to the lens.

[0025] The polarized patch disclosed herein, in some embodiments, comprises a PVA polarizing film bonded between two polymeric sheets. To create a suitable polarized patch, the optical retardation, modulus, and hardness of the polymeric sheets are selected to provide the user of the patch with polarization functionality comparable to that of conventional polarized sunglasses.

[0026] In order for the polarizing patch to achieve an anti-glare effect equivalent to that of ordinary polarized sunglasses, the optical retardation of the front polymer sheet, i.e., the side exposed to air when attached to the lens, is π / 5 radians or less, preferably π / 10 radians or less. The retardation of the polymer sheet is defined by the following formula:

number

[0027] In the above formula, Δn and L are the birefringence and thickness of the polymer sheet, respectively. 0 is the vacuum wavelength of the incident light. One way to minimize retardation is to choose a polymer sheet with low birefringence. Typically, the birefringence of a polymer sheet is due to orientation effects due to processing. Solution cast films generally have much lower azimuthal birefringence than extruded ones. In a preferred embodiment, the polarizing patch is made using a solution cast film, such as a cast polyvinyl chloride (PVC) film, or an extruded film of a material with low intrinsic birefringence, such as an aliphatic thermoplastic polyurethane (TPU).

[0028] Furthermore, for the polarizing patch to be flexible enough to conform to the shapes of lenses of various powers, the elastic modulus of the component polymeric sheet must be maintained below a certain threshold. In some embodiments, the elastic modulus of the component polymeric sheet is 700 MPa or less. Additionally, the thickness of the polymeric sheet is selected to enhance its flexibility. In some embodiments, the thickness of the polymeric sheet is 200 μm or less, preferably 100 μm or less. The Shore A hardness of the polymeric sheet material is selected to allow the polarizing patch to be applied to existing eyeglass lenses without the need for adhesives. In some embodiments, the Shore A hardness of the polymeric sheet material is preferably 60 or less.

[0029] [Example] Laminate samples were made using a nip roll laminator with pressure and gap control.

[0030] Example 1: PVC / PVA / PVC Polarized Patch A PVC / PVA / PVC polarizing patch, as shown in the exemplary embodiment of FIG. 1, was made using a 53 μm thick PVC layer, a 25 μm thick permanent acrylic adhesive layer, a 32 μm thick PVA film as the polarizing layer, and two 38 μm thick clear polyester liners as outer protective layers (not shown).

[0031] Example 2: TPU / PVA / TPU polarized patch TPU / PVA / TPU polarized patches, as shown in the exemplary embodiment of FIG. 2, were made with a 150 μm or 50 μm thick TPU film, a 40 μm thick PSA layer, and a 32 μm thick polarized PVA layer.

[0032] Example 3: PET / PVA / PET polarized patch PET / PVA / PET polarized patches were made using a 25 μm or 127 μm thick PET film, a 30-40 μm thick PSA layer, and a 32 μm thick PVA film.

[0033] Patch Characterization Birefringence Test Birefringence was tested by viewing an LCD screen through the laminate at various angles and observing the presence of a polychromatic birefringent pattern. Birefringence was then tested by attaching the ellipse to plano eyeglasses. The eyeglasses were worn by an observer in a sunny outdoor environment. While viewing glare (e.g., a car windshield), the presence of a polychromatic birefringent pattern was observed at various head tilt angles.

[0034] Adhesion Test A4 samples of perm / peel double-sided transfer adhesive were cut into thin strips. The protective release liner was removed from the high tack side of the transfer adhesive. The adhesive strips were then manually applied to fixed tint polarizer laminate film samples. Ellipses were then manually cut from the film using a cutting press. The adhesive strips were used in a configuration where the maximum coverage of the periphery of the ellipse was measured to be 3mm from the edge of the ellipse.

[0035] The adhesion of the ellipse was monitored by applying the ellipse to a convex sample lens and measuring the peel time.

[0036] PVC / PVA / PVC Polarized Patch Results Since the PVC film is non-birefringent (hence no optical retardation) and optically clear, the resulting PVC / PVA / PVC polarizing patch maintains the same polarizing efficiency as the PVA polarizing film alone. The PVC film has an elastic modulus of about 500 MPa and is therefore flexible and soft. The patch was applied with soapy water to the front side of a weak lens. For stronger lenses with larger surface curvature, PSA would need to be used.

[0037] The 53 μm thick PVC used to make the PVC / PVA / PVC polarized patches was stiff and these patches did not conform to the shape of strong lenses. A thinner PVC film, e.g., a 33 μm thick PVC film, mitigated this problem. The polarized patches exhibited high polarization efficiency, almost completely blocking light in the cross-polarized positions.

[0038] TPU / PVA / TPU Polarized Patch Results Like PVC films, TPU films have no birefringence or high transparency. The resulting polarized patches did not show any visible birefringence, and good adhesion and high polarization efficiency were observed for all types of lenses tested. The patches can be applied to the front side of low-power lenses without adhesive. Using PSA, the patches can be adhered to 7 and 8 degree lenses without issue and conform to the shape of the lens. The TPU polarized patches showed high polarization efficiency and almost completely blocked light in the cross-polarized positions.

[0039] PET / PVA / PET polarized patch results Good polarization efficiency was observed when the principal axis (towards the incident light) of the top PET layer was aligned with the polarization axis of the PVA. If the principal birefringent axes of the PET were not aligned, the polarization efficiency was reduced. The PET film was stiff, and the resulting polarized patch did not conform to the shape of some low power lenses without the adhesive.

[0040] Based on the above results, it was determined that TPU and clear PVC film were the most suitable outer layer materials for application of the polarized patch.

[0041] The claims should not be construed as including means- or step-plus-function limitations unless expressly recited in a given claim using the phrase "means for" or "step for," respectively.

Claims

1. A patch that reduces the transmission of light to a non-polarized optical component, a flat flexible laminate including at least one polarizing film; the patch is releasably securable to the non-polarizing optical component; the polarizing film includes a polarizing film sheet laminated between a first transparent polymer sheet on a front side and a second transparent polymer sheet on a back side in contact with the non-polarizing optical component; The patch, wherein the first and second transparent polymeric sheets have a tensile modulus of 700 MPa or less, a thickness of 200 μm or less, and a Shore A hardness of 60 or less.

2. The patch according to claim 1 , wherein the polarizing film sheet is a sheet containing PVA as a main component.

3. The patch of claim 1 , wherein the first and second transparent polymeric sheets are individually selected from PVC, TPU, or PDMS (polydimethylsiloxane).

4. The patch of claim 3 , wherein the first transparent polymeric sheet has an optical retardation of less than or equal to π / 5 radians.

5. The patch of claim 3 , wherein the first transparent polymeric sheet has an optical retardation of less than or equal to π / 10 radians.

6. The patch of claim 1 , wherein the patch has a tensile modulus of 700 MPa or less.

7. The patch of claim 1 , wherein the patch has a thickness of 200 μm or less.

8. The patch of claim 1 , wherein the patch has a Shore A hardness of 80 or less.

9. The patch of claim 1 , wherein the patch is releasably securable to the non-polarizing optic by electrostatic adhesion.

10. The patch of claim 1 , wherein the patch reduces light transmission for non-vertically polarized light.

11. The patch of claim 1 , wherein the patch is the same size and shape as the non-polarizing optic to which it is releasably securable.

12. The patch of claim 1 , wherein the patch is not the same size and shape as the non-polarizing optic to which it is releasably securable.

13. The patch of claim 12 , wherein the tensile modulus, thickness, and Shore A hardness are selected to provide the patch with flexibility for releasably attaching to the shape of a non-polarizing optic.

14. The patch of claim 1 , wherein the first and second transparent polymeric sheets have a thickness of 100 μm or less.

15. The patch of claim 1 , wherein the patch is applied to the lens using water or soapy water.

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