Contact lens package integrity testing using a linear actuator

Abstract

A method may include: introducing a contact lens blister package into a package integrity testing unit, wherein the contact lens blister package comprises a package base having a cavity, a contact lens disposed in the cavity, a packaging solution disposed in the cavity, and a material forming a seal over the cavity, and the package integrity testing unit comprises a linear actuator comprising an actuation arm; contacting the seal material with the actuation arm; measuring a deflection of the seal material; and detecting whether the contact lens blister package contains a defect based at least on the deflection of the seal material.

Description

CONTACT LENS PACKAGE INTEGRITY TESTING USING A LINEAR ACTUATORRELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 549,715, filed February 5, 2024.BACKGROUND

[0002] Contact lens blister packaging is a relatively economical option for storage of the lens prior to use by a wearer. The traditional blister pack for disposable lenses includes a package base comprising a well surrounded by a flange. The well contains the contact lens and packaging solution and is sealed along a seal region by a removable lid typically made of film, for example, a multilayer film comprising a sealing layer and a foil layer. The contact lens base is usually thermoformed plastic material produced by injection molding of polyethylene, polypropylene, polyvinyl chloride, or polyethylene terephthalate. The contact lens base has high stiffness but is capable of limited plastic deflection and includes a pre-formed well. The well is filled with a suitable packaging solution, preferably a buffered saline solution, and receives a single lens into the well. The well is then sealed and sterilized (e.g., autoclaved) using steam and pressure.

[0003] The package base serves several important functions for contact lenses. The package base protects the lens during transportation and keeps the contact lens hydrated by keeping the contact lens immersed in packaging solution. Package bases may be designed to support the immersed lens with the convex surface of the lens facing the removable lid or, with the concave (corneal contact) surface of the lens facing the removable lid. The package base also supports the lens such that during transportation, the lens does not fold or invert (which may result in incorrect application and use of the lens).

[0004] Package integrity testing is an important step in the production of contact lenses. The contact lens packaging must be leak proof to remain sterile and keep the lens hydrated. Current methods of package integrity testing require a technician to pull a representative amount of sample packages from each lot manufactured. The samples may be then subjected to a dye ingress test whereby the lens packages are submerged in a dye under vacuum. For contact lens packages with a defect, the dye may be pulled into the defective package under vacuum and thus be identifiable. If a package is deemed defective, the manufactured lot is disposed. While dye ingress testing iseffective at determining if an individual package is defective, dye ingress testing is unable to detect every defect in a manufactured lot. If a defective package is not in the representative sample, for example, the defective package may not be detected. Further, the dye ingress testing is time consuming and requires a quality control operator to physically select and handle each representative lot of samples and insert the samples into the dye and vacuum chamber. During the quality control testing, the manufactured lots may be placed on hold increasing work in progress (WIP) and lead time for manufactured lots.SUMMARY

[0005] Disclosed herein is an example method including: introducing a contact lens blister package into a package integrity testing unit, wherein the contact lens blister package comprises a package base having a cavity, a contact lens disposed in the cavity, a packaging solution disposed in the cavity, and a material forming a seal over the cavity, and the package integrity testing unit comprises a linear actuator comprising an actuation arm; contacting the material with the actuation arm; measuring a deflection of the material; and detecting whether the contact lens blister package contains a defect based at least on the deflection of the material.

[0006] Further disclosed herein is an example method including: introducing a contact lens blister package into a package integrity testing unit, wherein the contact lens blister package comprises a package base having a cavity, a contact lens disposed in the cavity, a packaging solution disposed in the cavity, and a material forming a seal over the cavity, and the package integrity testing unit comprises a moving coil actuator comprising an actuation arm; contacting the foil with the actuation arm with a force in a range of about 0.5 N to about 10.0 N; measuring a deflection of the foil; and detecting whether the contact lens blister package contains a defect based at least on the deflection of the material.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These drawings illustrate certain aspects of embodiments of the present invention and should not be used to limit or define the invention.

[0008] FIG. 1 is a schematic perspective view of an apparatus for the sterilization and secondary packaging of arrays of interconnected blister packages for the sterilized containment of contact lenses.

[0009] FIG. 2a is a schematic illustration of a blister package array.

[0010] FIG. 2b is a side view schematic illustration of a blister package array.

[0011] FIG. 2c is a schematic illustration of two blister package arrays nested together with the seal facing outwards.

[0012] FIG. 3 is an illustration showing a method for using a linear actuator to measure deflection of a foil seal in a blister pack.

[0013] FIG. 4 is a bar graph of an experiment showing displacement of a foil in a blister pack.DETAILED DESCRIPTION

[0014] Disclosed herein are methods of detecting defects in contact lens packaging, and more particularly disclosed herein are methods of detecting defects in contact lens packaging using a sterilization unit to evacuate a portion of a liquid within a contact lens packaging and detecting a change in volume of the liquid within the contact lens packaging.

[0015] Examples of the package integrity testing method include utilizing a sterilization unit to evacuate a portion of a liquid within a contact lens package and detecting a change in volume of the liquid within the contact lens package. The example methods provide several advantages over the previous methods of contact lens package integrity testing, only some of which may be alluded to herein. The example method of package integrity testing allows for in-line testing of every contact lens package that may be manufactured on a manufacturing line and thus quality may be assured for each contact lens package released to customers. The example methods also individually identify defective contact lens packages within a manufactured lot such that only the contact lens packages deemed defective are disposed of thus saving the remainder of the manufactured lot from being unnecessarily disposed of. The example in-line package integrity testing methods also reduce work in progress by eliminating the need to store manufactured lots while a representative sample of the manufactured lot is tested. The example methods of package integrity testing also allow for removal of several pieces of equipment and chemicals from the manufacturing process, as the vacuum equipment and dye solutions and are not required for the present methods, which reduces the number of waste streams associated with the manufacture of contact lenses. Additionally, the example methods may be automated thereby eliminating the need for an operator to manually handle the representative samples of contact lens packages thus reducing overhead costs associated with manufacturing the contact lens packages.Contact Lens Manufacturing Process

[0016] Contact lenses may be formed by introducing reactive mixtures into a mold where the mold defines the optical properties of the contact lens. The reactive mixtures may be cured by lightand / or heat to form the contact lens. After curing, the contact lens may be removed from the mold, subject to various processing steps such as hydration and extraction, and transferred to a packaging step where the contact lens may be deposited into a package base with a packaging solution. The finished blister pack containing the contact lens may then be sterilized, such as in an autoclave, before final packaging into cartons.

[0017] In a first step of contact lens manufacturing, reactive mixtures may be formed into contact lenses by dispensing the mixture into a mold assembly and subsequently curing the mixture. The mold assembly may include a base curve, which may be the mold half that contacts the posterior surface of the lens, and a front curve, which may be the mold half that contacts the anterior surface of the lens. The front curve and base curve, when brought together, may define and enclose a cavity between them which contains the reactive mixture.

[0018] The mold components (front curve and base curve) of the mold assembly may be made from various materials, including disposable or reusable materials. For instance, the mold may include a thermoplastic optical mold. The mold assembly may be made from any suitable material including, without limitation, polyethylene, polypropylene, polyolefins including homopolymers, copolymers, and terpolymers, polystyrene, polystyrene copolymers, polyesters such as poly(ethylene terephathalate) and poly(butylene terephthalate), polyamides, poly(vinyl alcohol) and its derivatives, hydrogenated styrene butadiene block copolymers, cyclic olefin polymers (COP) and copolymers (COC), and combinations thereof. COP plastic resins are commercially available from Zeon Chemicals (Zeonex and Zeonor resins), and Japan Synthetic Rubber (JSR). COC plastic resins are commercially available from Topas Advanced Polymers (Topas resins) and Mitsui (APEL resins). The mold may be selected to be transparent or mostly transparent to wavelengths that may activate the photoinitiator, thus permitting irradiation through the front and base curves. The material may be the same or different in the front and base curves. Examples of materials for the front curve of the mold assembly may include COP such as Zeonor 1060R or COC such as Topas 8007 or 5013 either neat or as a blend for example about 90: 10 (w / w) blend of COC or COP and hydrogenated styrene butadiene block copolymer, respectively. Examples of suitable materials for the base curve of the mold assembly may include COC, COP described above, polypropylene, blends thereof and blends with hydrogenated styrene butadiene block copolymer, about 90:10 (w / w) blend of cyclic olefin polymer and polypropylene.

[0019] Sources of activating radiation for initiating the photoinitiators may include, without limitation, lamps that transmit light at the appropriate wavelengths for such initiation. One method may include emitting activating radiation from a light emitting diode (LED) lamp. LED lamps may be utilized that transmit at the desired intensity and at a range of wavelengths that include from about 200 nanometers (nm) to about 600 nm. Alternatively, from about 300 nm to about 500 nm, most preferably from about 350 nm to about 450 nm.

[0020] The curing step may be carried out by exposing the reactive mixture to radiation or a combination thereof that includes the activating wavelength (the wavelength required to activate the photoinitiator). Radiation may be directed at either or both the base curve and the front curve of the mold assembly. The radiation may have a radiant energy at the base curve which may be greater than the radiation's radiant energy at the front curve.

[0021] The intensity of the radiation may generally be in the range of from about 0.1 mW / cm2to about 25 mW / cm2. Alternatively, from about 1 mW / cm2to about 10 mW / cm2, about 1 mW / cm2to about 15 mW / cm2, about 15 mW / cm2to about 25 mW / cm2, or any ranges therebetween.

[0022] After curing, the lens may be subjected to additional processing steps such as hydration to swell the lens, extraction to remove unreacted components from the lens, and release of the lens from the lens mold. These steps may take place in any order. The extraction may be carried out using extraction fluids, including, but not limited to, organic solvents, alcohols, aqueous solutions comprising water, and mixtures thereof. Examples of the aqueous solutions may include at least about 20 weight percent water, or at least about 50 weight percent water, or at least about 70 weight percent water, or at least about 95 weight percent water. Aqueous solutions may also include additional water-soluble compounds such as inorganic salts or release agents, wetting agents, slip agents, pharmaceutical and nutraceutical formulas, and combinations thereof. Release agents may include compounds or mixtures of compounds which, when combined with water, decrease the time required to release a contact lens from a mold, as compared to the time required to release such a lens using an aqueous solution that does not comprise the release agent.

[0023] Extraction may be accomplished, for example, via immersion of the lens in an extraction fluid or exposing the lens to a flow of an extraction fluid. Extraction may also include, for example, one or more of: heating the extraction fluid; stirring the extraction fluid; increasing the level of release aid in the extraction fluid to a level sufficient to cause release of the lens; mechanical or ultrasonic agitation of the lens; and incorporating at least one leaching or extraction aid in theaqueous solution to a level sufficient to facilitate adequate removal of unreacted components from the lens. The foregoing may be conducted in batch or continuous processes, with or without the addition of heat, agitation, or both. Before or after extraction of the lens and removal of the lens from the lens mold, the lens may be hydrated.

[0024] The lens may then be transferred to a packaging process where the lens and a packaging liquid may be deposited into a package base having a well therein. The packaging liquid may include an isotonic saline solution to prevent dehydration and to maintain the lenses in a ready-to- wear condition. The package base may be hermetically sealed with any suitable seal material including, for example, an aluminum laminate foil which may include aluminum sandwiched between layers of polyester printing materials and oriented polypropylene, to form a contact lens blister pack. The contact lens blister packs may be joined together by a continuous sheet of foil with perforations therein to provide blister pack arrays comprising two or more individual blister packs, wherein the perforations align on an edge between the blister packs such that individual blister packs may be separated from the blister pack array. The packaged lens may be then transferred to a sterilization process where packaged lenses may be sterilized by placing the blister pack in a sterilizing unit, such as an autoclave, at an elevated humidity, temperature, and pressure for a period of time.Reactive Mixture

[0025] ‘ ‘Conventional hydrogels” refer to polymeric networks made from components without any siloxy, siloxane or carbosiloxane groups. Conventional hydrogels may be prepared from reactive mixtures comprising hydrophilic monomers. Examples include 2-hydroxyethyl methacrylate (“HEMA”), N-vinyl pyrrolidone (“NVP”), N, N-dimethylacrylamide (“DMA”) or vinyl acetate. Conventional hydrogels may also be formed from polyvinyl alcohol. Conventional hydrogel lenses may contain a coating, and the coating may be the same or different material from the substrate. Conventional hydrogels may include additives such as polyvinyl pyrrolidone, and comonomers including phosphoryl choline, methacrylic acid and the like. Examples of conventional hydrogels include, but are not limited to, etafilcon, genfilcon, hilafilcon, lenefilcon, nesofilcon, omafilcon, polymacon, and vifilcon, including all of their variants.

[0026] “ Silicone hydrogels” refer to polymeric networks made from at least one hydrophilic component and at least one silicone-containing component. Examples of suitable families of hydrophilic components that may be present in the reactive mixture include (meth)acrylates,styrenes, vinyl ethers, (meth)acrylamides, N-vinyl lactams, N-vinyl amides, N-vinyl imides, N- vinyl ureas, O-vinyl carbamates, O-vinyl carbonates, other hydrophilic vinyl compounds, and mixtures thereof. The silicone-containing component may comprise at least one polymerizable group (e.g., a (meth)acrylate, a styryl, a vinyl ether, a (meth)acrylamide, an N-vinyl lactam, an N- vinylamide, an O-vinylcarbamate, an O-vinylcarbonate, a vinyl group, or mixtures of the foregoing), at least one siloxane group, and one or more linking groups (which may be a bond) connecting the polymerizable group(s) to the siloxane group(s). The silicone-containing components may, for instance, contain from about 1 siloxane repeat unit to about 220 siloxane repeat units. The silicone-containing component may also contain at least one fluorine atom. Silicone hydrogel lenses may contain a coating, and the coating may be the same or different material from the substrate. Examples of suitable silicone hydrogels may include acquafilcon, asmofilcon, balafilcon, comfilcon, delefilcon, enfilcon, fanfilcon, formofilcon, galyfilcon, kalifilcon, lotrafilcon, narafilcon, riofilcon, samfilcon, senofilcon, serafilcon, somofilcon, stenfilcon, and verofilcon including all of their variants.Initiators

[0027] The reactive mixture includes a photoinitiator. The photoinitiator may absorb (and be activated by) various wavelengths of light, for instant UV wavelengths and / or visible wavelengths. The photo initiator may absorb within the visible range (about 380 nm to about 780 nm) of the electromagnetic spectrum. Suitable visible light photoinitiators may include, but are not limited to, aromatic alpha-hydroxy ketones, alkoxyoxybenzoins, acetophenones, acylphosphine oxides, bisacylphosphine oxides, and a tertiary amine plus a diketone, mixtures thereof and the like. Examples of photoinitiators may include, but are not limited to, 1 -hydroxy cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-l-phenyl-propan-l-one, bis(2,6-dimethoxybenzoyl)-2,4-4- trimethylpentyl phosphine oxide (DMBAPO), bis(2,4,6-trimethylbenzoyl)-phenyl phosphineoxide (Irgacure 819), 2,4,6-trimethylbenzyldiphenyl phosphine oxide and 2,4,6- trimethylbenzoyl diphenylphosphine oxide, benzoin methyl ester and a combination of camphorquinone and ethyl 4-(N,N-dimethylamino)benzoate. The initiator may be included in the reactive mixture in effective amounts to initiate photopolymerization of the reactive mixture, including from about 0.1 to about 2 parts by weight per 100 parts of reactive monomer(s).

[0028] The reactive mixture may further include a thermal initiator which decomposes at a certain rate depending on the temperature. A thermal initiator may include, without limitations, an azocompound such as 1 , l'-azobisisobutyronitrile and 4,4'-azobis(4-cyanovaleric acid), peroxides such as benzoyl peroxide, tert-butyl peroxide, tert-butyl hydroperoxide, tert-butyl peroxybenzoate, dicumyl peroxide, and lauroyl peroxide, peracids such as peracetic acid and potassium persulfate, and combinations thereof.Package Integrity Testing

[0029] FIG. 1 illustrates a portion of a contact lens blister package production line and in particular, a perspective schematic representation of the overall operating structure of an apparatus 100 for implementing sterilization and package integrity testing as well as secondary packaging into cartons. While FIG. 1 illustrates one method of conveying blister package arrays into sterilization chamber 104, there may be several equivalent methods of conveying blister package arrays known in the art. Additionally, while blister package arrays as described in FIG. 1 are plural, the present methods are applicable to methods where one or more blister individual packs are utilized.

[0030] FIG. 1 illustrates the infeed of the blister package arrays 102 along the direction of arrow L into package integrity testing unit 112. The operation of package integrity testing unit 112 will be described in detail below. Arrow L may be from any another part of the contact manufacture process after the packaging process when the lens is disposed in the packaging fluid and the foil seal is applied to make the blister package. In package integrity unit 112, the foil seal of each blister package is checked for defects. Defective packages may be removed from circulation as indicated by arrow R and the remaining non-defective packages may be conveyed by arrow A so as to be placed in paired interleaved relationship by a product pick-up and rotating device as in arrows B. The interleaved blister package arrays 102 may be further conveyed to be positioned in spaces present between outwardly extending fingers of an endless loop-type tray loading shuttle conveyor assembly 106 which may be indexed forwardly in the direction of arrow C until all of the spaces along a vertical run thereof may be filled with paired interleaved blister package arrays 102, whereupon the conveyor assembly may be adapted to be temporarily brought to a standstill, and a suitable pusher 108 may transfer a vertical stack of the blister package arrays 102 from the conveyor into a vertical column or row of array-receiving spaces in an upended tray 110. The tray 110 may be intermittently indexed in the direction of arrow D until all of the vertical rows of spaces therein may be filled with interleaved pairs of blister package arrays 102. While illustrated in FIG.1 as interleaved blister package arrays, a single blister package array or an individual contact lens blister package may be inserted into tray 110.

[0031] As further illustrated in FIG. 1, the array-filled tray 110 conveyed along the direction of arrow E, while being prior thereto rotated in the direction of arrow F into a horizontal position and may be stacked with other similarly filled trays 110 to be conveyed into a sterilization chamber 104. The sterilization chamber 104 may include an autoclave. As will be discussed below, the sterilization chamber 104 may be operated in such a manner as to cause at least a portion of the packaging fluid present in defective blister package arrays 102 to escape from the blister package. From the sterilization chamber 104, the stacks of trays 110 with the blister package arrays 102 contained therein, may be then conveyed along the direction of the arrow G and introduced into package integrity testing unit 112. In package integrity testing unit 112, the sterilized blister packages 102 may be subjected to non-destructive testing to determine if there are any defective blister package arrays 102. The operation of package integrity testing unit 112 will be described in detail below. Defective packages may be removed from circulation as indicated by arrow R and the remaining non-defective packages may be conveyed to packaging as indicated by arrow H where the trays may be unstacked and individually advanced and upended in succession. The upended tray 110 may be positioned in alignment with an unloading shuttle conveyor assembly 116 to enable a pusher member to sequentially engage into vertical rows of spaces of the tray 110 housing the arrays of blister packages and transfer the latter into spaces present between outwardly extending fingers on a loop-type endless conveyor of assembly 116. The conveyor may be indexed forwardly in the direction of the arrow I, and a pusher element slides a succession of a plurality of sterilized arrays 102 of blister packages into the open end of a carton 114 which has been brought into alignment therewith by means of a cartoner. The filled cartons 114 may be then closed and sealed and conveyed along arrow J to suitable locations for further handling such as bundling as indicated by arrow K.

[0032] Sterilization chamber 104 includes a chamber for storing the blister package arrays 102 during a sterilization cycle. The chamber may be made of any suitable durable material such as stainless steel or alloys which may withstand the heat and pressure conditions during a sterilization cycle. The chamber may also include one or more doors for providing access to the chamber wherein the door may be designed with a tight seal to prevent leaks during the sterilization cycle. The one or more doors may include locking mechanisms and associated interlocks to prevent thedoor from opening during the sterilization cycle. The sterilization chamber may further include inlets and outlets as well as controllable valves operatively associated with the inlets and outlets to allow for the controlled flow of fluids and gases into the chamber. The sterilization chamber 104 may further include a pressure control system to manage and maintain the desired pressure levels within the chamber and may include components such as pressure relief valves and pressure transducers and / or strain gauges that send pressure data to a control system to monitor and regulate the pressure within the chamber. The sterilization chamber 104 may further include temperature sensors, such as thermocouples or resistance temperature detectors, which send temperature data to the control system to measure and control the temperature inside the chamber. Sterilization chamber 104 further includes a heating system to achieve and maintain the desired temperature within the chamber. The heating system may include electric or steam-powered heaters located either inside the chamber or in an external jacket surrounding it. For steam, a boiler and / or steam- powered heater may be operatively coupled to an inlet of the chamber. Sterilization chamber 104 further includes a control system for operating a sterilization cycle which may be further integrated into a distributed control system for a production line for contact lenses.

[0033] The control system may include a computer-based control system that may be used to monitor and control the different processes in the sterilization chamber. The control system typically comprises a number of components, including: sensors: these devices measure the physical properties of the process, such as temperature, pressure, and flow rate, controllers: these devices use the data from the sensors to calculate the necessary adjustments to the process, actuators: these devices implement the control commands from the controllers, such as opening or closing valves, and a human-machine interface (HMI) which may include a graphical user interface that allows operators to monitor and control the process. The control system uses various types of logic control such as PID controllers, ladder logic, and sequential function charts to control the processes. The logic control may be programmed into the control system software and may be used to ensure that the equipment operates within predefined limits.

[0034] A sterilization cycle may be initiated by the control system sending a signal to the controller associated with the steam system to open one or more of the inlet valves to the chamber. Before, during, and after the sterilization cycle, instrumentation reports back to the controller or control system conditions within the various parts of the sterilization chamber 104 such as steam pressure and temperature in lines, plant steam pressure and temperature, radiator pressure, air pressure andtemperature, water pressure and temperature, valve state, and safety interlock state, for example. The sterilization cycle typically includes increasing chamber pressure and temperature to a setpoint, holding the pressure and temperature at the setpoint for a determined period of time, and releasing the pressure while cooling the chamber using air for example. The sterilization cycle setpoint temperature, pressure, and hold time may be selected such that the contact lens blister pack is safely sterilized without compromising the lens or blister pack packaging. The rate of temperature and pressure ramping up and down may be controlled so that the lens and blister packaging is not damaged. For example, reducing the pressure within the chamber may cause the blister packaging to burst if the differential pressure across the foil seal is greater than the strength of the seal.

[0035] The set point temperature selected may be in a range of about 110 °C to about 140 °C. Alternatively, in a range of about 110 °C to about 120 °C, about 120 °C to about 130 °C, about 130 °C to about 140 °C, or any ranges therebetween. The set point pressure may be selected in a range of about 300 kPa to about 450 kPa. Alternatively, in a range of about 300 kPa to about 350 kPa, about 350 kPa to about 400 kPa, about 400 kPa to about 450 kPa, or any ranges therebetween. The ramp time for the sterilizer unit to reach the temperature set point may be a time in a range of from about 1 minute to about 5 minutes. Alternatively, in a range of about 1 minute to about 2 minutes, about 2 minutes to about 3 minutes, about 3 minutes to about 5 minutes, or any ranges therebetween. The ramp time for the sterilizer unit to reach the pressure set point may be a time in a range of from about 1 minute to about 5 minutes. Alternatively, in a range of about 1 minute to about 2 minutes, about 2 minutes to about 3 minutes, about 3 minutes to about 5 minutes, or any ranges therebetween. The hold time of the sterilizer cycle may be a value in a range of about 10 minutes to about 30 minutes. Alternatively, in a range of about 10 minutes to about 20 minutes, about 20 minutes to about 25 minutes, about 20 minutes to about 30 minutes, or any ranges therebetween. The sterilizer may have a ramp down time for the sterilizer unit to reach atmospheric pressure at a time in a range from about 5 minutes to about 20 minutes. Alternatively, in a range of about 5 minutes to about 10 minutes, about 10 minutes to about 15 minutes, about 15 minutes to about 20 minutes, or any ranges therebetween. The sterilizer may have a ramp down time for the sterilizer unit to reach ambient temperature at a time in a range from about 5 minutes to about 20 minutes. Alternatively, in a range of about 5 minutes to about 10 minutes, about 10 minutes to about 15 minutes, about 15 minutes to about 20 minutes, or any ranges therebetween.

[0036] As discussed above, the contact lens blister packaging may be damaged by the sterilization cycle or other parts of the manufacturing process such as during transportation and handling of the blister packs. Additionally, the blister pack may be defective at the seal formed between the package base and the lid, the lid may be defective, or the package base may be defective such that the sterility of the blister pack may not maintained. For these and other reasons, it may be desirable to have a process to determine whether the blister pack is defective for every blister pack in a manufactured lot.

[0037] A method to determine if a blister pack contains a defect is to apply a force to the seal of the blister pack and measure the deflection of the seal. The amount of deflection is then correlated to whether the blister pack is defective or intact. The seal in defective blister packages deflects to a greater degree than seals in intact packages. For intact blister packages, the volume of the headspace, which includes the packaging solution and any air or other gasses in the blister package, does not appreciably change through the different processing steps such as handling, sterilization, and packaging steps. The greater headspace volume in intact blister packages provides resistance to deflection and therefore deflect less than blister packages which have less headspace volume. For blister packages which contain a defect, the volume of the headspace may change from a portion of the packaging solution, air, or other gasses being removed from the blister package at various stages of production. Without being limited by theory, the volume of the headspace may change when a portion of the packaging fluid is evacuated from the blister package during the sterilization cycle such as by flashing a portion of the packaging solution to vapor, boiling off of a portion of the packaging solution, or a portion of the packaging solution being pumped out when the pressure in the sterilization chamber is lowered. Additionally, packaging solution and gases can leak off through a defect as the blister packages are handled.

[0038] The force may be applied to the seal using a linear actuator and the deflection is measured using any suitable measurement device. The force may be applied to the seal using a moving coil actuator and the deflection is measured using feedback from the moving coil actuator. The moving coil actuator includes a voice coil having a wire that is wound around a conductive cylinder, a permanent magnet arranged in a cylindrical shape around the voice coil, a rod connected to the voice coil to translate the linear motion of the voice coil, and a housing to direct magnetic flux and hold the rest of the components of the moving coil actuator. Current is passed through the voice coil to generate a magnetic field which interacts with the permanent magnet which generates aforce by the Lorentz force principle, to drive the rod connected to the voice coil. By varying the magnitude and direction of the current, the linear displacement of the rod is controlled. The moving coil actuator includes position sensors such as linear encoders or Hall effect sensors to provide accurate position data for the location of the rod. In further embodiments, the linear actuator includes an electro-mechanical linear actuator.

[0039] FIG. 2a is a schematic illustration of a blister package array 102. As illustrated, the blister package array 102 includes five adjacently located contact lens blister package 201. Each blister package 201 includes a package base 202 having a cavity 204 for the containment of a contact lens 206 immersed in a packaging solution, and with the blister package array 102 being sealingly covered by a single printed label-forming flexible foil seal 208, so as to be separable along perforation lines 210 into individual blister package 201, each respectively containing a single contact lens.

[0040] FIG. 2b is a side profile view of a single blister package array 102. As shown in FIG. 2b, blister package 201 includes cavity 204 being sealed by a foil seal 208. FIG. 2c is side profile view of two interleaved blister package arrays 102 nested together such that the foil seal 208 of each blister package 201 is facing outwards.

[0041] FIG. 3 is an illustration showing a method 300 for using a linear actuator to measure deflection of a foil seal in a blister pack. As shown in FIG. 3, blister package 201 is positioned below linear actuator 302 with foil seal 208 facing towards actuation arm 304. The actuation arm 304 is brought in contact with foil seal 208 and the actuation arm exerts a force with a known magnitude into foil seal 208. The deflection of the foil seal 208 is then measured either by feedback from the actuation arm 304 or by a separate measurement device. Linear actuator 302 includes position sensors such as linear encoders or Hall effect sensors to provide accurate position data for the location of actuation arm 304 to resolve the deflection amount of foil seal 208. The deflection of the foil seal may be measured using an optical microscopy technique coupled with softwarebased image analysis to measure the deflection. The deflection of the foil seal may be measured by interferometric techniques such as white-light interferometry and / or phase-shifting interferometry.

[0042] A package integrity testing unit such as package integrity testing unit 112 in FIG. 1, includes a linear actuator 302. The package integrity testing unit 112 is configured to accept a blister package 201 and position the blister package 201 under linear actuator 302 as described inFIG. 3 and the linear actuator 302 applies the force to the foil seal. The deflection of the foil seal is measured and compared against a threshold value of deflection to determine if the foil seal is deflected more than the threshold value which indicates that the blister package 201 contains a defect.

[0043] The linear actuator may be used in a variety of ways to determine if the blister package is defective. The actuation arm 304 may be brought into contact with the blister pack foil and the deflection of the foil may be measured over a period of time to determine if the measured deflection changes. The measured deflection may be compared to a nominal expected deflection over time for the package type and force applied through the actuation arm 304 into the foil to determine if the measured deflection is greater than the nominal expected deflection. If the measured deflection is greater than the nominal expected deflection, the package may be deemed defective. Alternatively, the actuation arm 304 and foil may be brought into contact at a calibrated distance and the resulting measured force may be used to determine if the foil is deflecting more than an expected nominal amount. The foil deflection from the nominal amount may then be correlated to a defect in the packaging.

[0044] The actuation arm may contact the foil seal with a force in a range of about 0.5 newtons (N) to about 10.0 N. Alternatively, the actuation arm contacts the foil seal with a force in a range of about 0.5 N to about 1.0 N, about 1.0 N to about 3.0 N, about 3.0 N to about 5.0 N, about 5.0 N to about 10.0 N, or any ranges therebetween. The force selected should not damage the foil seal but should also provide enough deflection such that a clear differentiation between the intact and defective blister packages can be made. The force may be selected such that foil seals of intact blister packages deflects by an amount of about 5 micrometers to about 100 micrometers. Alternatively, the force may be selected such that foil seals of intact blister packages deflects by an amount of about 5 micrometers to about 10 micrometers, about 10 micrometers to about 50 micrometers, about 50 micrometers to about 100, or any ranges therebetween.

[0045] The actuation arm may contact the foil seal with the force for a period to detect if deflection changes over time. For example, the application of a force to the foil seal can cause a portion of the packaging fluid to be evacuated from a defective blister package which may not be immediately detected but would be seen as a gradual increase in the foil deflection amount as the packaging fluid is pressed out of the defective blister package. The actuation arm may contact the foil sealfor about 1 second to about 1 minute. Alternatively, for about 1 second to about 10 seconds, about 10 seconds to about 30 seconds, about 30 seconds to about 1 minute, or any ranges therebetween.

[0046] The deflection of the foil seal may be compared to a deflection threshold value to determine if the blister package is intact or defective. The threshold value to differentiate between intact and defective blister packages may be in a range of about 100 micrometers to about 1500 micrometers. For example, a threshold value of 100 micrometers would mean that blister packages which deflect 100 micrometers or less are deemed intact and blister packages which deflect more than 100 micrometers would be deemed defective. Alternatively, the threshold value to differentiate between intact and defective blister packages may be in a range of about 100 micrometers to about 500 micrometers, about 500 micrometers to about 100 micrometers, about 1000 micrometers to about 1500 micrometers, or any ranges therebetween.Additional Embodiments

[0047] Accordingly, the present disclosure may provide methods of detecting defects in contact lens packaging using a sterilization unit to evacuate a portion of a liquid within a contact lens packaging and detecting a change in volume of the liquid within the contact lens packaging. The methods may include any of the various features disclosed herein, including one or more of the following embodiments.

[0048] Embodiment 1: A method comprising: introducing a contact lens blister package into a package integrity testing unit, wherein the contact lens blister package comprises a package base having a cavity, a contact lens disposed in the cavity, a packaging solution disposed in the cavity, and a material forming a seal over the cavity, and the package integrity testing unit comprises a linear actuator comprising an actuation arm; contacting the seal material with the actuation arm; measuring a deflection of the seal material; and detecting whether the contact lens blister package contains a defect based at least on the deflection of the seal material.

[0049] Embodiment 2. The method of embodiment 1 wherein the linear actuator comprises an electro-mechanical linear actuator.

[0050] Embodiment 3. The method of any of embodiments 1-2 wherein the linear actuator comprises a moving coil actuator.

[0051] Embodiment 4. The method of any of embodiments 1 -3 wherein the actuation arm contacts the seal material with a force in a range of about 0.5 N to about 10.0 N.

[0052] Embodiment 5. The method of any of embodiments 1 -4 wherein the actuation arm contacts the seal material such that the seal material of intact blister packages deflects by an amount of about 5 micrometers to about 100 micrometers.

[0053] Embodiment 6. The method of any of embodiments 1 -5 wherein the actuation arm contacts the seal material for a time period of about 1 second to about 1 minute.

[0054] Embodiment 7. The method of embodiment 6 wherein detecting whether the contact lens blister package has a defect based at least on the deflection of the seal material comprises measuring the deflection of the seal material for the time period and determining that the contact lens blister package contains a defect if the deflection of the seal material increases over the period of time.

[0055] Embodiment 8. The method of any of embodiments 1-7 wherein measuring the deflection of the seal material comprises determining a position of the actuation arm using one or more hall effect sensors in the linear actuator.

[0056] Embodiment 9. The method of any of embodiments 1-8 wherein measuring the deflection of the seal material comprises determining a position of the actuation arm using one or more linear encoders in the linear actuator.

[0057] Embodiment 10. The method of any of embodiments 1-9 wherein measuring the deflection of the seal material comprises measuring using an optical microscopy technique.

[0058] Embodiment 11. The method of any of embodiments 1-10 wherein measuring the deflection of the seal material comprises measuring using an interferometric technique selected from white-light interferometry, phase-shifting interferometry, and combinations thereof.

[0059] Embodiment 12. The method of any of embodiments 1-11 where detecting whether the contact lens blister package contains a defect based at least on the deflection of the seal material comprises comparing the measured deflection to a deflection threshold value and determining that the contact lens blister package contains a defect if the deflection of the seal material is greater than the deflection threshold value.

[0060] Embodiment 13. The method of embodiment 12 wherein the deflection threshold value is about 100 micrometers to about 1500 micrometers.

[0061] Embodiment 14. The method of any of embodiments 1-13 wherein the package integrity testing unit is part of a contact lens blister package production line, and wherein the packageintegrity testing unit is positioned before and / or after a sterilizer unit in the contact lens blister package production line.

[0062] Embodiment 15. A method comprising: introducing a contact lens blister package into a package integrity testing unit, wherein the contact lens blister package comprises a package base having a cavity, a contact lens disposed in the cavity, a packaging solution disposed in the cavity, and a material forming a seal over the cavity, and the package integrity testing unit comprises a moving coil actuator comprising an actuation arm; contacting the seal material with the actuation arm with a force in a range of about 0.5 N to about 10.0 N; measuring a deflection of the seal material; and detecting whether the contact lens blister package contains a defect based at least on the deflection of the seal material.

[0063] Embodiment 16. The method of embodiment 15 wherein the actuation arm contacts the foil such that seal material of intact blister packages deflect by an amount of about 5 micrometers to about 100 micrometers.

[0064] Embodiment 17. The method of embodiment 15-16 wherein detecting whether the contact lens blister package contains a defect based at least on the deflection of the seal material comprises comparing the measured deflection to a deflection threshold value and determining that the contact lens blister package contains a defect if the deflection of the seal material is greater than the deflection threshold value.

[0065] Embodiment 18. The method of embodiment 15-17 wherein the deflection threshold value is about 100 micrometers to about 1500 micrometers.

[0066] Embodiment 19. The method of embodiment 15-18 wherein the actuation arm contacts the seal material for a time period of about 1 second to about 1 minute.

[0067] Embodiment 20. The method of embodiment 15-19 wherein detecting whether the contact lens blister package has a defect based at least on the deflection of the seal material comprises measuring the deflection of the seal material for the time period and determining that the contact lens blister package contains a defect if the deflection of the seal material increases over the period of time.

[0068] To facilitate a better understanding of the present invention, the following examples of certain aspects of some embodiments are given. In no way should the following examples be read to limit, or define, the entire scope of the disclosure.EXAMPLES

[0069] In this example, linear actuators were utilized to measure the deflection of intact foil seals of blister packages and contact blister packages produced with intentional defects. Five defective blister packages were produced by laying an 80 micron wire across the foil seal surface prior to heat sealing the foil seal to the package base to introduce an 80 micron defect in the seal. The wire was then removed. The test setup consisted of 5 moving coil linear actuators configured to apply a constant force to the foil of the blister package and report back the displacement. The results of the experiment are shown in FIG. 4. It was observed that the intact no wire blister packages had an average displacement of about 120 micrometers for the selected force whereas the defective package bases had an average displacement of about 1000 micrometers.

[0070] It is to be understood that the present disclosure is not limited to particular methods, which may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. All numbers and ranges disclosed herein may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. Although individual embodiments are discussed herein, the invention covers all combinations of all those embodiments. As used herein, the singular forms “a”, “an”, and “the” include singular and plural referents unless the content clearly dictates otherwise. Furthermore, the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not in a mandatory sense (i.e., must). The term' “include,” and derivations thereof, mean “including, but not limited to.” The term “coupled” means directly or indirectly connected. If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted for the purposes of understanding this invention.

[0071] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range fallingwithin the range are specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values even if not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

[0072] The scope of the present disclosure includes any feature or combination of features disclosed herein (either explicitly or implicitly), or any generalization thereof, whether or not it mitigates any or all of the problems addressed herein. Various advantages of the present disclosure have been described herein, but embodiments may provide some, all, or none of such advantages, or may provide other advantages.

Claims

What is claimed is:

1. A method comprising: introducing a contact lens blister package into a package integrity testing unit, wherein the contact lens blister package comprises a package base having a cavity, a contact lens disposed in the cavity, a packaging solution disposed in the cavity, and a material forming a seal over the cavity, and the package integrity testing unit comprises a linear actuator comprising an actuation arm; contacting the seal material with the actuation arm; measuring a deflection of the seal material; and detecting whether the contact lens blister package contains a defect based at least on the deflection of the seal material.

2. The method of claim 1 wherein the linear actuator comprises an electro-mechanical linear actuator.

3. The method of claim 1 wherein the linear actuator comprises a moving coil actuator.

4. The method of claim 1 wherein the actuation arm contacts the seal material with a force in a range of about 0.5 N to about 10.0 N.

5. The method of claim 1 wherein the actuation arm contacts the seal material such that seal material of intact blister packages deflects by an amount of about 5 micrometers to about 100 micrometers.

6. The method of claim 1 wherein the actuation arm contacts the seal material for a time period of about 1 second to about 1 minute.

7. The method of claim 6 wherein detecting whether the contact lens blister package has a defect based at least on the deflection of the seal material comprises measuring the deflection of the sealmaterial for the time period and determining that the contact lens blister package contains a defect if the deflection of the seal material increases over the period of time.

8. The method of claim 1 wherein measuring the deflection of the seal material comprises determining a position of the actuation arm using one or more hall effect sensors in the linear actuator.

9. The method of claim 1 wherein measuring the deflection of the seal material comprises determining a position of the actuation arm using one or more linear encoders in the linear actuator.

10. The method of claim 1 wherein measuring the deflection of the seal material comprises measuring using an optical microscopy technique.

11. The method of claim 1 wherein measuring the deflection of the seal material comprises measuring using an interferometric technique selected from white-light interferometry, phaseshifting interferometry, and combinations thereof.

12. The method of claim 1 wherein detecting whether the contact lens blister package contains a defect based at least on the deflection of the seal material comprises comparing the measured deflection to a deflection threshold value and determining that the contact lens blister package contains a defect if the deflection of the seal material is greater than the deflection threshold value.

13. The method of claim 12 wherein the deflection threshold value is about 100 micrometers to about 1500 micrometers.

14. The method of claim 1 wherein the package integrity testing unit is part of a contact lens blister package production line, and wherein the package integrity testing unit is positioned before and / or after a sterilizer unit in the contact lens blister package production line.

15. The method of claim 1 wherein the seal material is a multi-layer film.

16. The method of claim 1 wherein the seal material is a multi-layer film comprising at least a foil layer and a sealing layer.

17. A method comprising: introducing a contact lens blister package into a package integrity testing unit, wherein the contact lens blister package comprises a package base having a cavity, a contact lens disposed in the cavity, a packaging solution disposed in the cavity, and a material forming a seal over the cavity, and the package integrity testing unit comprises a moving coil actuator comprising an actuation arm; contacting the seal material with the actuation arm with a force in a range of about 0.5 N to about 10.0 N; measuring a deflection of the seal material; and detecting whether the contact lens blister package contains a defect based at least on the deflection of the seal material.

18. The method of claim 17 wherein the actuation arm contacts the seal material such that seal material of intact blister packages deflect by an amount of about 5 micrometers to about 100 micrometers.

19. The method of claim 17 wherein detecting whether the contact lens blister package contains a defect based at least on the deflection of the seal material comprises comparing the measured deflection to a deflection threshold value and determining that the contact lens blister package contains a defect if the deflection of the seal material is greater than the deflection threshold value.

20. The method of claim 17 wherein the deflection threshold value is about 100 micrometers to about 1500 micrometers.

21. The method of claim 17 wherein the actuation arm contacts the seal material for a time period of about 1 second to about 1 minute.

22. The method of claim 21 wherein detecting whether the contact lens blister package has a defect based at least on the deflection of the seal material comprises measuring the deflection of the seal material for the time period and determining that the contact lens blister package contains a defect if the deflection of the seal material increases over the period of time.

Images