Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
  • B29C51/10—Forming by pressure difference, e.g. vacuum
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D11/00—Producing optical elements, e.g. lenses or prisms
  • B29D11/00009—Production of simple or compound lenses
  • B29D11/00019—Production of simple or compound lenses with non-spherical faces, e.g. toric faces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D11/00—Producing optical elements, e.g. lenses or prisms
  • B29D11/0073—Optical laminates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/30—Polarising elements
  • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
  • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
• • G—PHYSICS
  • G02—OPTICS
  • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
  • G02C7/00—Optical parts
  • G02C7/12—Polarisers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2791/00—Shaping characteristics in general
  • B29C2791/004—Shaping under special conditions
  • B29C2791/007—Using fluid under pressure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2011/00—Optical elements, e.g. lenses, prisms
  • B29L2011/0016—Lenses
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2325/00—Polymers of vinyl-aromatic compounds, e.g. polystyrene
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2377/00—Polyamides
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S623/00—Prosthesis, i.e. artificial body members, parts thereof, or aids and accessories therefor
  • Y10S623/901—Method of manufacturing prosthetic device
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31507—Of polycarbonate
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31551—Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
  • Y10T428/31565—Next to polyester [polyethylene terephthalate, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31786—Of polyester [e.g., alkyd, etc.]

Definitions

• the field of the present invention relates to ophthalmic lenses, and particularly to an ophthalmic lens utilizing a polarizing film.
• ophthalmic lenses are known as described in, for example, U.S. Patent Nos . 4,418,992 and 4,274,717, each of these disclosures hereby incorporated by reference as if fully set forth herein.
• Such lenses may comprise a number of different types of materials ranging from inorganic to thermoset plastics, such as allyl diglycol carbonate sold under the CR-39 ⁇ trademark of PPG Industries, Inc. ("CR-39®”), to more recent formulations using thermoplastic materials, such as polycarbonate (“PC”) .
• polarizers used in hard resin thermoset lenses or polycarbonate thermoplastic lenses are based on polyvinylalchohol ("PVA") films imbued with a polarizing material.
• PVA polyvinylalchohol
• the polarizing film is either adhesively bonded to a lens substrate, or it is placed within a mold assembly and the liquid resin mixture placed around it (sequentially or simultaneously) to form the lens.
• the film is commonly part of a multi-layer construction (often referred to as a wafer) designed for better rigidity and thermal stability.
• thermoplastic lens manufacturing for example, monomer or polymeric pellets are heated past their softening point (for PC, above 230°C),and injected into a mold form.
• softening point for PC, above 230°C
• Conventional polarizer films comprising PVA or similar polymers cannot withstand these temperatures. For instance, PVA has its glass transition temperature (“T g ”) between 90- 95°C, and softens with decomposition at approximately 200°C.
• the PVA film lose its shape, but it will also lose physical integrity (color, polarization efficiency, mechanical strength, etc.) at typical molding temperatures .
• the dyes or polarizing commonly agents used therein are also temperature-sensitive. The temperature-sensitivity of the common polarized film and the dyes or polarizing agents used therein can cause severe non-uniformity or non- reproducibility, adversely affecting either the optical and cosmetic quality of a given lens or lot-to-lot consistency.
• U.S. Patent No. 5,059,356 which is incorporated by reference as if fully set forth herein, discloses a polarized film of polyethylene terephthalate (PET) .
• PET polyethylene terephthalate
• This material has several advantages over PVA, including affordability, significantly better heat, moisture, and solvent resistance, and good mechanical stability. It is also more stable to ultra-violet radiation (UV) , which is especially useful for lens production and coating processes with UV curing cycles.
• UV ultra-violet radiation
• the present inventors recognized that an ophthalmic lens utilizing PET film might offer advantages over an ophthalmic lens utilizing current PVA film if the PET film could be reliably incorporated into ophthalmic lens manufacture.
• the present inventors are unaware of effective use of PET film in ophthalmic lenses. Its absence of incorporation into ophthalmic lens manufacture can be attributed to a number of different reasons. The primary reason is due to PET's chemical inertness. A secondary reason includes PET' s relatively low degree of optical quality, which is not able to match or accommodate ophthalmic lenses.
• the present inventors have experimented with PET film and noted that PET cannot be reliably adhered within or to the lens and additional coatings cannot be reliably adhered to the PET film.
• simple adhesive boncing application of liquid adhesives or glues
• additional processing such as grinding to prescription strength or be subjected to additional coating processes for mechanical or optical enhancement.
• the preferred embodiments relate to an ophthalmic lens having a PET polarizing film integrally bonded thereto and, optionally, a hard coating integrally bonded to the PET polarizing film after it has been bonded to the lens.
• the PET film may be surface treated, either physically and/or chemically, for integrally bonding the film to the lens substrate.
• the film may be physically and/or chemically surface treated for integrally bonding the hard coating to the PET film.
• Various other embodiments may utilize some but not all of the above elements, or may include additional refinements, while obtaining the benefit of an ophthalmic lens utilizing PET film.
• Fig. 1 shows an ophthalmic thermoplastic lens utilizing PET polarizing film, wherein the lens is constructed according to a preferred embodiment
• Fig. 2 shows an ophthalmic thermoset lens utilizing PET polarizing film, wherein the lens is constructed according to a preferred embodiment
• Fig. 3 shows a detailed view of the integral bonding that occurs between the PET polarizing film and the lens substrate, and particularly illustrates the integral bond between the PET film within the thermoset lens substrate shown in Fig. 2;
• Fig. 4 is a flowchart illustrating the general process of using PET polarizing film in ophthalmic lenses
• Fig. 5 is a flowchart illustrating thermoset lens forming that utilizes PET polarizing film according to a preferred embodiment
• Fig. 6 is a flowchart illustrating thermoplastic lens forming that utilizes PET polarizing film according to a preferred embodiment.
• Fig. 1 shows an ophthalmic thermoplastic lens 100 utilizing PET polarizing film 102, wherein the lens 100 is constructed according to a preferred embodiment.
• the ophthalmic lens 100 includes a lens substrate or lens material 104 having a PET polarizing film 102 integrally bonded thereto and a hard coating 106 integrally bonded to the film 102 after it has been bonded to the lens substrate 104.
• the film may be surface treated, either physically and/or chemically, to effect an integral bond 108 (such a bond being shown in detail in Fig. 3 with respect to a thermoset lens) between the film 102 and the lens substrate 104, i.e., the film 102 is unsupported and directly bonded to the substrate 104.
• the film 102 may be physically and/or chemically surface treated to effect an integral bond 112 between the hard coating 106 and the film 102.
• Fig. 2 shows an ophthalmic thermoset lens 200 utilizing PET polarizing film 202, wherein the lens 200 is constructed according to a preferred embodiment.
• the thermoset lens 200 includes a lens substrate or material 204 having a PET polarizing film 202 integrally bonded thereto.
• film 202 is bonded near the front surface 212 of the lens substrate 204.
• film 202 is interposed between first and second members 204a, 204b of substrate 204.
• the first member 204a of the lens material 204 protects the film 202, there may be no need to hardcoat it.
• member 204a may optionally be hardcoated.
• the hard coating 206 is optional, it is shown in dashed lines.
• both sides of the PET film 202 may be surface treated, either physically and/or chemically, to effect an integral bond 208 between the film 202 and the second substrate member 204b and an integral bond 210 between the film 202 and the first substrate member 204a. Bonds 208, 210 are shown in detail in Fig. 3. Should a hard coat be desired, the first member 204a of substrate 204 may be surface treated to improve adhesion of the hard coating 206 to the member 204a.
• the lens substrate or material may comprise a thermoset material or a thermoplastic material .
• the preferred materials comprise polymers from diethylene glycol bis (allyl carbonate) or diallyl diglycol carbonate, such as CR-39® or PPG, or Akzo Nobel brand NS205.
• the lens substrate may comprise other thermoset materials such as polymers of 1,3 butylene glycol dimethacrylate, acrylonitrile, allyl methacrylate, ethoxymethyl methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate; ally esters; co-polymers of allyl esters with styrene or vinyl type monomers, such as diallyl maleate, diallyl phthalate, methallyl methacrylate, etc.; and high index copolymers containing, e.g., vinyl functionality, isocyanates, urethanes, sulfur-containing aromatic vinyl compounds, and bromine-containing aromatic acrylic compounds.
• thermoset materials such as polymers of 1,3 butylene glycol dimethacrylate, acrylonitrile, allyl methacrylate, ethoxymethyl methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate; ally esters; co-polymers of allyl
• the preferred materials comprise PC resin such as that sold by Bayer, Inc. of Pittsburgh, PA under their trademarks Makrolon® DPI-1821 or 1815, or Lexan® OQ2720 manufactured by General Electric.
• the lens substrate may comprise other thermoplastic materials such as polysulfones, polyethersulfones, polyamides, polystyrenes; and mixtures of polycarbonate and polyurethanes, polyesters, polysulfones, polystyrenes, amorphous polyolefins, and acrylics.
• the PET film should be of very high optical quality to match ophthalmic standards, such as Developmental Film 99-04 manufactured by R&S Enterprises of Yokohama, Japan with a polarizing efficiency of at least 96.3% and a transmission average (400-700 nm) of 14-18%.
• the present inventors currently prefer the un-annealed form to the standard annealed form of Developmental Film 99-04 manufactured by R&S Enterprises.
• the PET film may further comprise a crystalline or semi-crystalline naphthalene dicarboxylic acid, such as polyethylene naphthalate polyester or a copolymer derived from ethylene glycol, naphthalene dicarboxylic acid, and some other acids such as terephthalate .
• the hard coating may comprise an SDC hardcoat, such as SDC-1175, for thermoplastic lenses and an LTI-UV cured hardcoat, such as LTI-SHC-175Y, 33% solids, for thermoset lenses .
• SDC hardcoat such as SDC-1175
• LTI-UV cured hardcoat such as LTI-SHC-175Y, 33% solids, for thermoset lenses .
• a general process 300 of using PET polarizing film in ophthalmic lenses includes the first step of "Form film to curve" 302 for forming the film to curve or fit the desired shape of the lens substrate or material.
• the film may be curved or formed by techniques commonly known to those skilled in the art as described in, for example, U.S. Patent No. 5,434,707, which disclosure is hereby incorporated by reference as if fully set forth herein.
• the next step includes "Treat film surface for improved adhesion to lens material” 304.
• the film surface should be prepared or treated. Different surface treatments or coatings may be necessary to achieve the best adhesion with different materials (e.g., lens material vs. coating material) . This point is especially true for chemical bonding, which requires compatible reactive sites. In other words, when PET is subjected to UV or plasma treatments, a common chemical change is the formation of either radicals or phenolic groups (aromatic rings with -OH groups) on the treated surface.
• these groups can be effective for strong bonding or can even repel the new material.
• these groups are beneficial species for improved bonding to subsequent thermal and UV curing hard coatings. Because of the molecular structure of CR39®-type hard resins and PC, UV and plasma treatment may also enhance adhesion to these materials as well.
• the type of surface "treatment" of the film may vary.
• a polyurethane coating may be applied by itself to the film to integrally bond with the lens substrate.
• the film surface Prior to the polyurethane coating, the film surface may be prepared or treated by using physical and/or chemical treatments. The physical treatment may include, for example, scrub roughening of the surface to achieve a "Velcro" effect.
• the film may also be chemically prepared or treated for bond-breaking and bond formation between the surface and the subsequent layers by coating the film with a reactive layer, e.g., the film may be coated with a layer having reactive groups or the film may be coated with a layer containing -OH groups.
• step 304 is the step of "Form solid lens with film at or near front surface" 306.
• thermoset lens forming those skilled in the art may use techniques commonly known to them as described in, for example, U.S. Patent No. 5,286,419 and Applicant's ABO- approved presentation on sunwear, copyright 1999, each of these disclosures hereby incorporated by reference as if fully set forth herein.
• thermoplastic lens forming those skilled in the art may use techniques commonly known to them as described in, for example, U.S. Patent No. 5,051,309, which disclosure is hereby incorporated by reference as if fully set forth herein.
• the next step in the overview of the general ophthalmic manufacturing process 300 includes "Treat outer surface of film/lens (if needed) for improved adhesion of hard coating” 308.
• the film surface may treated, physically and/or chemically, for integrally bonding the film to the hard coating.
• a hard coating may be applied as illustrated in step "Apply hard coating (if desired)" 310.
• thermoset lens forming 400 that utilizes PET polarizing film according to a preferred embodiment.
• the first step includes "form film to curve" 402. Similar to the general process 300 flowchart illustrated in Fig. 4, the film may be formed or shaped using conventional techniques known those skilled in the art.
• the next step involves prepping the surface of the film to allow the film to integrally bond to the lens substrate. As shown in Fig. 5, the step is "Treat film surface for improved adhesion to lens material, e.g., - coat both film surfaces with polyurethane-based material, but do not cure coating, or -UV treat surface, or - plasma treat surface" 404.
• both sides of the film or both film surfaces may be coated or dipped with an uncured polyurethane-based material or UV treated or plasma treated.
• UV treatment conventional techniques known to those skilled in the art may be employed such as that described in, for example, “The Influence of Vacuum-Ultraviolet Radiation on Poly (ethylene terephthalate) , " Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 34, pp. 1511-1516 (1996), which disclosure is hereby incorporated by reference as if fully set forth herein.
• the plasma treatment conventional techniques known to those skilled in the art may be employed such as that described in, for example, “Plasma Treatment for Improved Bonding: A Review," J. Adhesion, Vol. 30, pp. 199-218 (1989) and “Plasma Sources for Polymer Surface Treatment," Handbook of Thin Film Process Technology (1996), which disclosures are hereby incorporated by reference as if fully set forth herein.
• the next steps are "Place film in gasket of lens assembly” 406, "Introduce lens monomer above and below film, either in equal or unequal amounts for desired film positioning” 408, and “Cure lens monomer by standard thermoset methods (heat, UV, hot bath, etc.)” 410.
• the polyurethane bond is preferably strengthened for at least three hours as illustrated in the step of "Strengthen polyurethane bond (if used) by additional cure (e.g., 100°C, 3+ hours)" 412.
• step 416 optionally includes treating the outer surface of the lens to improve adhesion of an optionally applied hard coating.
• the surface treatment of the lens may be physical or chemical treatments, or a combination thereof, which may include mechanical roughening of the lens substrate, chemical modification of the surface tension, chemical modification of the surface reactivity, or UV or plasma exposure.
• Step 416 is illustrated in Fig. 5 as "Treat outer surface of lens (if needed) for improved adhesion of subsequent hard coat, e.g., -Mechanical roughening of lens material (CR scrub) - Chemical modification of surface tension - Chemical modification of surface reactivity - Coat with layer containing -OH groups -UV or plasma exposure" .
• thermoplastic lens forming 500 that utilizes PET polarizing film according to a preferred embodiment.
• the first step of "Form film to curve" 502 is similar to steps 302, 402, respectively illustrated in Figs. 4 and 5.
• the next step of "Treat film surface for improved adhesion to lens material, e.g., - coat inner film surface with polyurethane-based material, but do not cure coating, or - UV or plasma treat surface” 504 is directed to preparing the inner surface of the film facing the lens substrate, such as substrate 104, for integral bonding thereto.
• This temperature will cause severe damage to a free-standing or unsupported film, but could also affect the optical properties of a PET film (because of the low T g ) .
• Carefully controlling the temperature of molding protects the PET from burning while still allowing the PC to flow smoothly within the mold. Typically, this control means dropping the molding temperatures approximately 30°F for all stages of the molding process.
• the next step of "Treat film at front surface of thermoplastic Lens for improved adhesion to hard coating” 510 involves prepping the outer surface of the film for integrally bonding the lens to the hard coating. This step may be effected in one of two ways, depending on whether the lens will experience UV exposure as illustrated in the step of "Will lens experience UV exposure during treatment or subsequent coating" 512.
• step 514 If “YES,” as shown in step 514, and if polyurethane was used, as shown in steps “Was polyurethane coating used?" 518 and "YES" 520, then the polyurethane/thermoplastic material bond should be strengthened as illustrated in the step of "Strengthen polyurethane/PC bond by e.g., 100°C, 8+ hour cure" 526.
• the outside surface of the film may optionally be treated to integrally bond the optional hard coating to the film as shown in the step of "Treat film/lens for improved adhesion to hard coat, e.g., - UV or plasma exposure - Coat film with layer having reactive groups - Coat film with layer having reactive -OH groups" 528.
• the hard coating should be applied and then cured as shown in the steps of "Apply UV or thermal hard coat” 530 and "Cure UV or thermal hard coat” 532.
• the outer surface of the film is then preferably chemically treated for optionally bonding a hard coating thereto, as shown in the steps of "NO” 516 and "Coat with reactive layer for chemical bond to thermal hard coat, e.g., - Coat film with layer having reactive groups - Coat film with layer containing -OH groups” 524.
• the hard coating should be applied and cured for integrally bonding the hard coating to the film as shown in the steps of "Apply thermal hard coat” 534 and "Thermally cure hard coating” 536.
• a 4D (diopters of lens power, referenced to a refractive index of 1.53) curved PET film was positioned within a 4D single vision lens insert cavity of a polycarbonate-molding machine. Standard PC molding conditions were used to inject PC into the same cavity to form a polarized single vision lens.
• Adhesion of the lens/film combination was not consistently acceptable, as measured by cutting a narrow cross-section of the lens, scoring into the lens from the back almost to the front surface, and then breaking the lens along the score line to determine where adhesion is lost.
• the intrinsic cohesiveness of the PET was exceeded before the lens delaminated. This means that a very strong bond was achieved.
• adhesion failure often occurred at the interface between the PET and the back surface of the lens.
• the adhesion of subsequent hard coats was also inconsistent.
• a wet chemical hard coat (approximately 4 microns thick) was applied by standard spin coating techniques, then cured by infrared and UV light exposure for 25 seconds.
• This polarized lens was not compromised in color or polarizing efficiency by exposure to ultraviolet (UV) light during the hard coating process.
• UV ultraviolet
• the adhesion of the hard coat to the PET surface as tested by the ASTM method of cross-hatch scoring of the hard coated surface, pressing 3M brand 810 tape firmly across the cut surface, and snap tape testing, showed highly variable results.
• some lenses showed no coating removal, while others showed partial or entire removal of coating in the tested area.
• thermoset lens casting assembly two glass lens surface molds, spaced apart from each other and held in that configuration by an outer plastic gasket
• Standard lens casting procedures were used to form a hard resin lens around the PET film.
• Adhesion as measured by the cross-sectioning test described above showed moderate adhesion, with less than 20% delamination between the PET film surface and the resin lens interfaces .
• Example 3 demonstrates the advantages allowed by treating the surface of the PET film prior to forming the solid lens with the film at or near the front surface of the lens substrate.
• Example 3 is directed to thermoplastic lens forming.
• both sides of the PET film may be coated or dipped with polyurethane in thermoset lens forming, the advantages of such treatment may equally apply to thermoset optical manufacturing.
• Example 4 demonstrates the advantages allowed by surface treating the lens/film prior to the optional hardcoating step. Although optional, most ophthalmic lenses are hardcoated for improved abrasion resistance of at least the front surface of the lens. This step is particularly important for PC lenses because the softer material is easily scratched even in packaging and transport. Accordingly, Example 4 is primarily directed to thermoplastic lens forming, however, it also demonstrates the advantages of treating the lens surface of a thermoset lens should this lens be hardcoated.
• Adhesion was tested by cross-hatch cutting the hardcoated surface, pressing 3M-brand 810 tape firmly across the cut region and quickly pulling the tape from the surface. An improvement in adhesion is indicated if less material is removed form the cross-hatched region, but a "fail” is still recorded if any coating is removed from the squares of the cross-hatch.
• a PET polarized ophthalmic lens and methods of ophthalmic lens manufacture are disclosed, wherein the manufacturing process integrally bonds the PET film to the lens substrate and optional hard coating without losing its required physical properties. While preferred embodiments are disclosed herein, many variations are possible which remain within the concept and scope of the invention. Such variations would become clear to one of ordinary skill in the art after inspection of the specification and drawings herein. The inventions therefore are not to be restricted except within the spirit and scope of the appended claims .

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• Engineering & Computer Science (AREA)
• Ophthalmology & Optometry (AREA)
• Health & Medical Sciences (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Optics & Photonics (AREA)
• General Physics & Mathematics (AREA)
• Manufacturing & Machinery (AREA)
• General Health & Medical Sciences (AREA)
• Surface Treatment Of Optical Elements (AREA)
• Polarising Elements (AREA)
• Eyeglasses (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)

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• 1999
  • 1999-12-29 US US09/475,424 patent/US6220703B1/en not_active Expired - Lifetime
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