Contact lens package integrity testing using linear actuators

Abstract

One method may include: introducing a contact lens blister package into a packaging integrity testing unit, wherein the contact lens blister package includes a packaging 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 packaging integrity testing unit includes a linear actuator including an actuation arm; contacting the sealing material with the actuation arm; measuring the deflection of the sealing material; and detecting whether the contact lens blister package contains defects, at least based on the deflection of the sealing material.

Description

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

[0002] Contact lens blister packaging is a relatively economical option for storing lenses before use by the wearer. Traditional blister packaging for disposable lenses includes a packaging base comprising a cavity surrounded by a flange. This cavity contains the contact lens and a packaging solution and is sealed along a sealing area by a removable cap, typically made of a film (e.g., a multilayer film including a sealing layer and a foil layer). The contact lens base is typically a thermoformed plastic material produced by injection molding of polyethylene, polypropylene, polyvinyl chloride, or polyethylene terephthalate. The contact lens base has high rigidity but is capable of limited plastic deflection and includes a pre-formed cavity. This cavity is filled with a suitable packaging solution, preferably a buffered saline solution, and a single lens is accommodated within the cavity. The cavity is then sealed and sterilized using steam and pressure (e.g., autoclaving).

[0003] The packaging base provides several important functions for the contact lens. It protects the lens during transport and maintains its hydration by keeping it submerged in the packaging solution. The packaging base can be designed to support the submerged lens, with either the convex surface of the lens facing the removable cap, or the concave (corneal contact) surface of the lens facing the removable cap. The packaging base also supports the lens to prevent it from folding or inverting during transport (which could lead to incorrect application and use of the lens).

[0004] Packaging integrity testing is a critical step in contact lens production. Contact lens packaging must be leak-proof to maintain sterility and lens hydration. Current packaging integrity testing methods require technicians to remove a representative number of sample packages from each batch manufactured. These samples are then subjected to dye entry testing, whereby the lens package is immersed in dye under vacuum. For defective contact lens packages, dye can be drawn into the defective package under vacuum and is therefore identifiable. If the packaging is deemed defective, the entire batch manufactured is discarded. While dye entry testing is effective in determining whether an individual package is defective, it cannot detect every defect in a manufacturing batch. For example, if a defective package is not among the representative samples, it may not be detected. Furthermore, dye entry testing is time-consuming and requires quality control operators to physically select and handle samples from each representative batch and insert them into the dye and vacuum chamber. During quality control testing, the manufacturing batch may be paused, increasing work-in-process (WIP) and delivery time for the batch. Summary of the Invention

[0005] This document discloses an example method comprising: introducing a contact lens blister pack into a packaging integrity testing unit, wherein the contact lens blister pack includes a packaging 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 packaging integrity testing unit includes a linear actuator including an actuator arm; contacting the material with the actuator arm; measuring the deflection of the material; and detecting whether the contact lens blister pack contains defects, at least based on the deflection of the material.

[0006] This document also discloses an example method comprising: introducing a contact lens blister package into a packaging integrity testing unit, wherein the contact lens blister package includes a packaging 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 packaging integrity testing unit includes a moving-coil actuator including an actuator arm; contacting the foil with the actuator arm with a force in the range of about 0.5 N to about 10.0 N; measuring the deflection of the foil; and detecting whether the contact lens blister package contains defects based at least on the deflection of the material. Attached Figure Description

[0007] These figures illustrate certain aspects of embodiments of the invention and should not be construed as limiting or restricting the invention.

[0008] Figure 1 This is a schematic perspective view of a device used for sterilizing and repackaging an interconnected blister pack array for sterilizing contact lenses.

[0009] Figure 2a is a schematic diagram of a blister pack array.

[0010] Figure 2b is a side view of the blister pack array.

[0011] Figure 2c is a schematic diagram of two nested blister pack arrays with the seals facing outwards.

[0012] Figure 3 This is a diagram illustrating a method for measuring the deflection of foil seals in blister packaging using a linear actuator.

[0013] Figure 4 This is a bar graph showing the displacement of the foil in blister packaging. Detailed Implementation

[0014] This article discloses a method for detecting defects in contact lens packaging, and more specifically, this article discloses a method for detecting defects in contact lens packaging by using a sterilization unit to drain a portion of the liquid inside the contact lens packaging and detecting the volume change of the liquid inside the contact lens packaging.

[0015] Examples of packaging integrity testing methods include using a sterilization unit to drain a portion of the liquid within the contact lens packaging and detecting changes in the volume of the liquid within the contact lens packaging. The example methods offer several advantages over previous methods for testing the integrity of contact lens packaging, some of which may only be mentioned herein. The example methods for packaging integrity testing allow for in-line testing of each contact lens package that can be manufactured on a production line, and thus ensure the quality of each contact lens package released to the customer. The example methods also individually identify defective contact lens packages within a manufacturing batch, so that only those considered defective are disposed of, thus avoiding unnecessary disposal of the rest of the manufacturing batch. The example in-line packaging integrity testing methods also reduce ongoing work by eliminating the need to store the manufacturing batch while testing a representative sample of the batch. The example methods for packaging integrity testing also allow for the removal of several pieces of equipment and chemicals from the manufacturing process, as the method of the present invention does not require vacuum equipment and dye solutions, which reduces the amount of waste stream associated with contact lens manufacturing. Furthermore, the example methods can be automated, thereby eliminating the need for operators to manually handle representative samples of contact lens packaging, thus reducing the overhead costs associated with manufacturing contact lens packaging.

[0016] Contact lens manufacturing method Contact lenses can be formed by introducing a reactive mixture into a mold, where the mold defines the optical properties of the contact lens. The reactive mixture can be photo- and / or thermally cured to form the contact lens. After curing, the contact lens can be removed from the mold and subjected to various processing steps, such as hydration and extraction, and transferred to a packaging step, in which the contact lens can be deposited into a packaging base along with a packaging solution. The finished blister pack containing the contact lens can then be sterilized, such as in an autoclave, before final packaging into a carton.

[0017] In the first step of contact lens manufacturing, a reactive mixture can be formed into a contact lens by dispensing the mixture into a mold assembly and subsequently curing the mixture. The mold assembly may include a bottom curved surface and a front curved surface, the bottom curved surface being a mold half of the rear surface of the contact lens, and the front curved surface being a mold half of the rear surface of the contact lens. When joined together, the front and bottom curved surfaces can define and enclose a cavity between them containing the reactive mixture.

[0018] The molding components of the mold assembly (front-curved mold and bottom-curved mold) can be made of a variety of materials, including disposable or reusable materials. For example, the mold may include a thermoplastic optical mold. The mold assembly can be made of any suitable material, including but not limited to polyethylene, polypropylene, polyolefins (including homopolymers, copolymers, and terpolymers), polystyrene, polystyrene copolymers, polyesters such as poly(ethylene terephthalate) and poly(butylene terephthalate), polyamide, 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 nearly transparent to the wavelength of the activated photoinitiator, thereby allowing irradiation through the front and bottom curved surfaces. The materials in the front and bottom surfaces may be the same or different. Examples of materials for the front surface of the mold assembly may include COP (such as Zeonor 1060R) or COC (such as Topas 8007 or 5013), either pure or as blends, such as approximately 90:10 (w / w) blends of COC or COP with hydrogenated styrene-butadiene block copolymers, respectively. Examples of suitable materials for the bottom surface of the mold assembly may include the aforementioned COC, COP, polypropylene, blends thereof, and blends with hydrogenated styrene-butadiene block copolymers. Blends of approximately 90:10 (w / w) cyclic olefin polymers and polypropylene may also be used.

[0019] The activating radiation source for initiating a photoinitiator may include, but is not limited to, a lamp that emits light at a suitable wavelength for such initiation. One method may include emitting activating radiation from a light-emitting diode (LED) lamp. An LED lamp that emits radiation at a desired intensity and in a wavelength range including from about 200 nanometers (nm) to about 600 nm can be used. Alternatively, from about 300 nm to about 500 nm, most preferably from about 350 nm to about 450 nm.

[0020] The curing step can be achieved by exposing the reactive mixture to radiation or a combination thereof, including an activation wavelength (i.e., the wavelength required to activate the photoinitiator). The radiation can be directed to either or both of the bottom and front surfaces of the mold assembly. The radiation energy at the bottom surface may be greater than the radiation energy at the front surface.

[0021] The intensity of the radiation is typically around 0.1 mW / cm². 2 Approximately 25 mW / cm2 Within that range. Alternatively, at approximately 1 mW / cm². 2 Approximately 10 mW / cm 2 Approximately 1mW / cm 2 Approximately 15 mW / cm 2 Approximately 15mW / cm 2 Approximately 25 mW / cm 2 , or any range thereof.

[0022] After curing, the lens can undergo further processing steps, such as hydration to cause swelling, extraction to remove unreacted components from the lens, and release of the lens from the lens mold. These steps can be performed in any order. Extraction can be performed using an extraction fluid, including but not limited to organic solvents, alcohols, aqueous solutions including water, and mixtures thereof. Examples of aqueous solutions may include at least about 20% by weight of water, or at least about 50% by weight of water, or at least about 70% by weight of water, or at least about 95% by weight of water. Aqueous solutions may also include additional water-soluble compounds, such as inorganic salts or release agents, wetting agents, slip agents, pharmaceuticals and nutritional preparations, and combinations thereof. Release agents may include compounds or mixtures of compounds that, when combined with water, reduce the time required to remove the contact lens from the mold compared to using an aqueous solution without a release agent.

[0023] Extraction can be achieved, for example, by immersing the lens in an extraction fluid or exposing the lens to a flowing extraction fluid. Extraction may also include one or more of the following: heating the extraction fluid; agitating the extraction fluid; increasing the level of a release agent in the extraction fluid to a level sufficient to detach the lens; mechanically or ultrasonically stirring the lens; and incorporating at least one filtration or extraction agent into an aqueous solution until a level sufficient to promote adequate removal of unreacted components from the lens. The above operations can be performed in batch or continuous methods, with or without heating, agitation, or both. The lens can be hydrated before or after removal from the lens mold.

[0024] The lenses can then be transferred to a packaging process, where the lenses and packaging liquid are deposited into a packaging base having cavities therein. The packaging liquid may include an isotonic saline solution to prevent dehydration and keep the lenses in a wear-ready state. The packaging base can be hermetically sealed with any suitable sealing material, including, for example, aluminum laminate foil, which may include aluminum sandwiched between a polyester printed material layer and an oriented polypropylene layer to form a contact lens blister package. The contact lens blister packages can be joined together by continuous foil sheets having perforations therein to provide an array of blister packages comprising two or more individual blister packages, wherein the perforations are aligned on the edges between the blister packages so that individual blister packages can be separated from the blister package array. The packaged lenses can then be transferred to a sterilization process, where the packaged lenses are sterilized by placing the blister packages in a sterilization unit (such as an autoclave) under elevated humidity, temperature, and pressure for a period of time.

[0025] Reactive mixtures "Conventional hydrogels" refer to polymer networks made from components that do not contain any siloxy, siloxane, or carbosiloxane groups. Conventional hydrogels can be prepared from reactive mixtures including hydrophilic monomers. Examples include 2-hydroxyethyl methacrylate ("HEMA"), N-vinylpyrrolidone ("NVP"), N,N-dimethylacrylamide ("DMA"), or vinyl acetate. Conventional hydrogels can also be formed from polyvinyl alcohol. Conventional hydrogel lenses may contain a coating, and the coating may be the same as or different from the substrate material. Conventional hydrogels may include additives such as polyvinylpyrrolidone, and comonomers including phosphorylcholine, methacrylic acid, etc. Examples of conventional hydrogels include, but are not limited to, etafilcon, genfilcon, hilafilcon, lenefilcon, nesofilcon, omafilcon, polymacon, and vifilcon, including all their variations.

[0026] "Organosilicon hydrogel" refers to a polymer network made of at least one hydrophilic component and at least one component containing organosilicon. Examples of suitable types of hydrophilic components that may be present in the reactive mixture include (meth)acrylates, styrene, vinyl ethers, (meth)acrylamide, N-vinyl lactam, N-vinylamide, N-vinylimide, N-vinylurea, O-vinylcarbamate, O-vinyl carbonate, other hydrophilic vinyl compounds, and mixtures thereof. The organosilicon-containing component may include at least one polymerizable group (e.g., (meth)acrylate, styrene, vinyl ether, (meth)acrylamide, N-vinyl lactam, N-vinylamide, O-vinylcarbamate, O-vinyl carbonate, vinyl group, or mixtures thereof), at least one siloxane group, and one or more linking groups (which may be bonds) connecting one or more polymerizable groups to one or more siloxane groups. The organosilicon-containing component may, for example, contain from about 1 siloxane repeating unit to 220 siloxane repeating units. The organosilicon-containing component may also contain at least one fluorine atom. Silicone hydrogel lenses may include a coating, and the coating may be the same as or different from the substrate. Examples of suitable silicone hydrogels may include acquafilcon, asmofilcon, balafilcon, comfilcon, delefilcon, enfilcon, fanfilcon, formofilcon, galyfilcon, kalificlon, lotrafilcon, narafilcon, riofilcon, samfilcon, senofilcon, serafilcon, somofilcon, stenfilcon, and verofilcon, including all their variants.

[0027] Initiator The reactive mixture includes a photoinitiator. This photoinitiator can absorb (and be activated by) light of various wavelengths, such as UV wavelengths and / or visible wavelengths. The photoinitiator can absorb light in the visible range of the electromagnetic spectrum (approximately 380 nm to approximately 780 nm). Suitable visible light photoinitiators may include, but are not limited to, aromatic α-hydroxy ketones, alkoxyoxophenyl ketones, acetophenones, acylphosphine oxides, diacylphosphine oxides, and tertiary amine diketones, mixtures thereof, etc. Examples of photoinitiators include, but are not limited to, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-prop-1-one, bis(2,6-dimethoxybenzoyl)-2,4-4-trimethylpentylphosphine oxide (DMBAPO), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure819), 2,4,6-trimethylbenzyl diphenylphosphine oxide and 2,4,6-trimethylbenzoyl diphenylphosphine oxide, methyl benzoin, and combinations of camphorquinone and ethyl 4-(N,N-dimethylamino)benzoate. An effective amount of the initiator that can initiate the photopolymerization of the reactive mixture (including about 0.1 parts by weight to about 2 parts by weight per 100 parts of one or more reactive monomers) is included in the reactive mixture.

[0028] The reactive mixture may also include a thermal initiator that decomposes at a certain rate depending on the temperature. The thermal initiator may include, but is not limited to, azo compounds such as 1,1'-azobisisobutyronitrile and 4,4'-azobis(4-cyanopentanoic 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.

[0029] Packaging integrity test Figure 1 This illustration depicts a portion of a contact lens blister packaging production line, and specifically, a perspective schematic representation of the overall operational structure of equipment 100 used for performing sterilization and packaging integrity testing, as well as secondary packaging into cartons. Although Figure 1 An example of conveying an array of blister packs into a sterilization chamber 104 is illustrated, but several equivalent methods of conveying arrays of blister packs known in the art are possible. Furthermore, although as... Figure 1 The blister pack arrays described herein are multiple, but the method of the present invention is applicable to methods that utilize one or more blister packs for single packaging.

[0030] Figure 1An example is shown where blister pack array 102 enters packaging integrity testing unit 112 in the direction of arrow L. The operation of packaging integrity testing unit 112 will be described in detail below. Arrow L can originate from any other part of the manufacturing process that came into contact with the blister pack after the packaging process, when the lens is placed in the packaging fluid and a foil seal is applied to prepare the blister pack. In packaging integrity unit 112, the foil seal of each blister pack is inspected for defects. Defective packs can be removed from the flow as indicated by arrow R, while the remaining undefective packs can be conveyed as indicated by arrow A for placement in a paired, staggered relationship via a product pick-up and rotation device as indicated by arrow B. The staggered blister pack array 102 can also be conveyed to be positioned in the space between the outwardly extending fingers of the endless loop pallet loading shuttle assembly 106, which can be forward-rotated in the direction of arrow C until all the space along its vertical travel is filled with pairs of staggered blister pack arrays 102. The conveyor assembly can then be adapted to temporarily stop, and a suitable pusher 108 can transfer the vertical stack of blister pack arrays 102 from the conveyor to the array receiving space of vertical columns or rows in the inverted pallet 110. The pallet 110 can be intermittently rotated in the direction of arrow D until all the spaces in its vertical rows are filled with staggered pairs of blister pack arrays 102. Although Figure 1 The example shown is an interlaced array of blister packs, but a single array of blister packs or a single contact lens blister pack can be inserted into tray 110.

[0031] like Figure 1As further illustrated, the array filling tray 110 is conveyed in the direction of arrow E, while being rotated to a horizontal position in the direction of arrow F beforehand, and can be stacked with other similarly filled trays 110 for conveying into the sterilization chamber 104. The sterilization chamber 104 may include an autoclave. As will be discussed below, the sterilization chamber 104 can be operated in such a manner that at least a portion of the packaging fluid present in the defective blister pack array 102 escapes from the blister packs. The stack of trays 110 containing the blister pack array 102 can then be conveyed from the sterilization chamber 104 in the direction of arrow G and introduced into the packaging integrity test unit 112. In the packaging integrity test unit 112, the sterilized blister packs 102 can undergo non-destructive testing to determine the presence of any defective blister pack arrays 102. The operation of the packaging integrity test unit 112 will be described in detail below. Defective packages can be removed from the cycle as indicated by arrow R, and the remaining defect-free packages can be conveyed for packaging as indicated by arrow H, in which trays can be destacking and continuously and individually advanced and inverted. The flipped tray 110 can be positioned to align with the unloading reciprocating conveyor assembly 116, allowing the pusher element to sequentially engage into the vertical row of spaces containing the blister pack arrays of the tray 110, and to transfer the blister pack arrays into the spaces between outwardly extending fingers present on the endless loop conveyor of assembly 116. The conveyor can be rotated forward in the direction of arrow I, and the pusher element slides a series of multiple sterilized blister pack arrays 102 into the open end of a carton 114, which has been aligned with it by a cartoning machine. The filled carton 114 can then be closed and sealed, and conveyed along arrow J to the appropriate location for further processing, such as strapping as indicated by arrow K.

[0032] The sterilization chamber 104 includes a cavity for storing the blister pack array 102 during sterilization cycles. The cavity can be made of any suitable durable material, such as stainless steel or an alloy, which can withstand thermal and pressure conditions during sterilization cycles. The cavity may also include one or more doors to provide access to the cavity, wherein the doors may be designed with tight seals to prevent leakage during sterilization cycles. One or more doors may include locking mechanisms and associated interlocks to prevent the doors from opening during sterilization cycles. The sterilization chamber may also include inlets and outlets, and controllable valves operatively associated with the inlets and outlets to allow controlled flow of fluids and gases into the cavity. The sterilization chamber 104 may also include a pressure control system to manage and maintain a desired pressure level within the cavity, and may include components such as pressure relief valves and pressure transducers and / or strain gauges that transmit pressure data to the control system to monitor and regulate the pressure within the cavity. The sterilization chamber 104 may also include temperature sensors, such as thermocouples or resistance temperature detectors, that transmit temperature data to the control system to measure and control the temperature within the cavity. The sterilization chamber 104 also includes a heating system to achieve and maintain a desired temperature within the chamber. The heating system may include an electric heater or a steam-powered heater located inside the chamber or in an external jacket surrounding the chamber. For steam, a boiler and / or a steam-powered heater may be operatively coupled to the chamber inlet. The sterilization chamber 104 also includes a control system for operating the sterilization cycle, which may be further integrated into a distributed control system for the contact lens production line.

[0033] This control system may include a computer-based control system that can be used to monitor and control various processes within the sterilization chamber. The control system typically includes multiple components, including: sensors: these devices measure the physical properties of the process, such as temperature, pressure, and flow rate; controllers: these devices use data from the sensors to calculate necessary adjustments to the process; actuators: these devices implement 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 process. Logic control can be programmed into the control system software and can be used to ensure that the equipment operates within predefined limits.

[0034] The sterilization cycle can be initiated by the control system sending a signal to the controller associated with the steam system to open one or more inlet valves leading to the chamber. Before, during, and after the sterilization cycle, the instrumentation reports conditions within the various sections of the sterilization chamber 104 to the controller or control system, such as steam pressure and temperature in the pipelines, plant steam pressure and temperature, radiator pressure, air pressure and temperature, water pressure and temperature, valve status, and safety interlock status. The sterilization cycle typically involves increasing the chamber pressure and temperature to a setpoint, maintaining the pressure and temperature at the setpoint for a defined period of time, and releasing the pressure while using, for example, air to cool the chamber. The sterilization cycle setpoint temperature, pressure, and holding time can be selected so that contact lens blister packs are safely sterilized without damaging the lenses or blister packs. The rates of increase and decrease in temperature and pressure can be controlled so that the lenses and blister packs are not damaged. For example, if the pressure differential across the foil seal is greater than the strength of the seal, reducing the pressure within the chamber may cause the blister packs to burst.

[0035] The selected setpoint temperature can be in the range of approximately 110°C to approximately 140°C. Alternatively, it can be in the range of approximately 110°C to approximately 120°C, approximately 120°C to approximately 130°C, approximately 130°C to approximately 140°C, or any range therebetween. The setpoint pressure can be selected in the range of approximately 300 kPa to approximately 450 kPa. Alternatively, it can be in the range of approximately 300 kPa to approximately 350 kPa, approximately 350 kPa to approximately 400 kPa, approximately 400 kPa to approximately 450 kPa, or any range therebetween. The ramp time for the sterilizer unit to reach the temperature setpoint can be in the range of approximately 1 minute to approximately 5 minutes. Alternatively, it can be in the range of approximately 1 minute to approximately 2 minutes, approximately 2 minutes to approximately 3 minutes, approximately 3 minutes to approximately 5 minutes, or any range therebetween. The ramp time for the sterilizer unit to reach the pressure setpoint can be in the range of approximately 1 minute to approximately 5 minutes. Alternatively, the duration of the sterilizer cycle may be within the range of approximately 1 minute to approximately 2 minutes, approximately 2 minutes to approximately 3 minutes, approximately 3 minutes to approximately 5 minutes, or any range therebetween. The holding time of the sterilizer cycle may be a value within the range of approximately 10 minutes to approximately 30 minutes. Alternatively, the duration may be within the range of approximately 10 minutes to approximately 20 minutes, approximately 20 minutes to approximately 25 minutes, approximately 20 minutes to approximately 30 minutes, or any range therebetween. The sterilizer may have a descent time for the sterilizer unit to reach atmospheric pressure within the range of approximately 5 minutes to approximately 20 minutes. Alternatively, the duration may be within the range of approximately 5 minutes to approximately 10 minutes, approximately 10 minutes to approximately 15 minutes, approximately 15 minutes to approximately 20 minutes, or any range therebetween. The sterilizer may have a descent time for the sterilizer unit to reach ambient temperature within the range of approximately 5 minutes to approximately 20 minutes. Alternatively, the duration may be within the range of approximately 5 minutes to approximately 10 minutes, approximately 10 minutes to approximately 15 minutes, approximately 15 minutes to approximately 20 minutes, or any range therebetween.

[0036] As discussed above, contact lens blister packs can be damaged by the sterilization cycle or other parts of the manufacturing process, such as during transport and handling. Additionally, the seal formed between the blister pack base and the cap may be defective; the cap itself may be defective, or the pack base may be defective, making it impossible to maintain the sterility of the blister pack. For these and other reasons, a process may be necessary to determine whether each blister pack in a manufacturing batch is defective.

[0037] The method for determining whether a blister pack contains a defect is to apply force to the seal of the blister pack and measure the deflection of the seal. The amount of deflection is then correlated with whether the blister pack is defective or intact. Seals in defective blister packs deflect to a greater extent than seals in intact packs. For intact blister packs, the volume of the headspace (which includes the packaging solution and any air or other gases within the blister pack) does not change significantly during different processing steps, such as handling, sterilization, and packaging. The larger headspace volume in intact blister packs provides resistance to deflection and therefore results in less deflection than in blister packs with a smaller headspace volume. For blister packs containing defects, the volume of the headspace can change due to the removal of a portion of the packaging solution, air, or other gases from the blister pack at various stages of production. Without being bound by theory, the volume of the headspace may change when a portion of the packaging fluid is withdrawn from the blister pack during a sterilization cycle, such as by flashing a portion of the packaging solution into vapor, boiling a portion of the packaging solution, or pumping a portion of the packaging solution out when the pressure in the sterilization chamber decreases. Additionally, when handling blister packaging, the packaging solution and gas may leak due to defects.

[0038] A linear actuator can be used to apply force to the seal, and the deflection can be measured using any suitable measuring device. A moving-coil actuator can be used to apply force to the seal, and the deflection can be measured using feedback from the moving-coil actuator. A moving-coil actuator includes: a voice coil having a wire 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 movement of the voice coil; and a housing that guides the magnetic flux and holds the remaining components of the moving-coil actuator. Current flows through the voice coil to generate a magnetic field that interacts with the permanent magnet, which generates a force through the Lorentz force principle to drive the rod connected to the voice coil. The linear displacement of the rod is controlled by changing the magnitude and direction of the current. The moving-coil actuator includes a position sensor, such as a linear encoder or a Hall effect sensor, to provide accurate position data of the rod's position. In another embodiment, the linear actuator includes an electromechanical linear actuator.

[0039] Figure 2a is a schematic diagram of a blister pack array 102. As illustrated, the blister pack array 102 includes five adjacently positioned contact lens blister packs 201. Each blister pack 201 includes a packaging base 202 having a cavity 204 for receiving a contact lens 206 immersed in a packaging solution, and wherein the blister pack array 102 is sealed and covered by a single flexible foil seal 208 formed by a printed label so that it can be separated into individual blister packs 201 along a perforation line 210, each blister pack containing a single contact lens.

[0040] Figure 2b is a side profile view of a single blister pack array 102. As shown in Figure 2b, the blister pack 201 includes a cavity 204 sealed by a foil seal 208. Figure 2c is a side profile view of two nested, staggered blister pack arrays 102 such that the foil seal 208 of each blister pack 201 faces outward.

[0041] Figure 3 This is an illustration of a method 300 for measuring the deflection of a foil seal in blister packaging using a linear actuator. Figure 3 As shown, a blister pack 201 is positioned below a linear actuator 302, with a foil seal 208 facing an actuator arm 304. The actuator arm 304 contacts the foil seal 208 and applies a force of known magnitude to the foil seal 208. The deflection of the foil seal 208 is then measured via feedback from the actuator arm 304 or via a separate measuring device. The linear actuator 302 includes a position sensor, such as a linear encoder or a Hall effect sensor, to provide accurate position data of the position of the actuator arm 304, thereby resolving the amount of deflection of the foil seal 208. The deflection of the foil seal can be measured using optical microscopy techniques coupled to software-based image analysis. The deflection of the foil seal can also be measured using interferometric techniques such as white light interferometry and / or phase-shifting interferometry.

[0042] Packaging integrity test unit (such as Figure 1 The packaging integrity test unit 112 includes a linear actuator 302. The packaging integrity test unit 112 is configured to accept blister packs 201 and position the blister packs 201 below the linear actuator 302, such as... Figure 3 As described herein, the linear actuator 302 applies a force to the foil seal. The deflection of the foil seal is measured and compared to a deflection threshold to determine whether the foil seal has deflected beyond the threshold, which indicates that the blister pack 201 contains a defect.

[0043] Linear actuators can be used in several ways to determine if blister packaging is defective. Actuation arm 304 can contact the blister packaging foil and measure the deflection of the foil over a period of time to determine if the measured deflection has changed. The measured deflection can be compared to a nominal expected deflection over time, for that packaging type and the force applied to the foil via actuation arm 304, 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 packaging can be considered defective. Alternatively, actuation arm 304 and the foil can contact at a calibrated distance, and the resulting measured force can be used to determine if the foil deflects beyond the expected nominal amount. The foil deflection deviating from the nominal amount can then be correlated with defects in the packaging.

[0044] The actuating arm can contact the foil seal with a force ranging from about 0.5 Newtons (N) to about 10.0 N. Alternatively, the actuating arm can contact the foil seal with a force ranging from 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 range thereof. The selected force should not damage the foil seal but should also provide sufficient deflection to allow clear differentiation between intact and defective blister packs. A force can be selected such that the foil seal of an intact blister pack is deflected by about 5 micrometers to about 100 micrometers. Alternatively, a force can be selected such that the foil seal of an intact blister pack is deflected by about 5 micrometers to about 10 micrometers, about 10 micrometers to about 50 micrometers, about 50 micrometers to about 100 micrometers, or any range thereof.

[0045] The actuator arm can forcefully contact the foil seal for a period of time to detect whether the deflection changes over time. For example, applying force to the foil seal may cause some packaging fluid to be expelled from a defective blister pack. This may not be immediately detected, but will be considered as a gradual increase in foil deflection as the packaging fluid is forced out of the defective blister pack. The actuator arm can contact the foil seal for approximately 1 second to approximately 1 minute. Alternatively, the contact may last for approximately 1 second to approximately 10 seconds, approximately 10 seconds to approximately 30 seconds, approximately 30 seconds to approximately 1 minute, or any range therebetween.

[0046] The deflection of the foil seal can be compared to a deflection threshold to determine whether the blister pack is intact or defective. The threshold for distinguishing between intact and defective blister packs can range from approximately 100 micrometers to approximately 1500 micrometers. For example, a threshold of 100 micrometers would mean that a blister pack with a deflection of 100 micrometers or less would be considered intact, and a blister pack with a deflection greater than 100 micrometers would be considered defective. Alternatively, the threshold for distinguishing between intact and defective blister packs can range from approximately 100 micrometers to approximately 500 micrometers, from approximately 500 micrometers to approximately 100 micrometers, from approximately 1000 micrometers to approximately 1500 micrometers, or any range in between.

[0047] Additional Implementation Plan Therefore, this disclosure provides a method for detecting defects in contact lens packaging by using a sterilization unit to drain a portion of the liquid within the contact lens packaging and detecting changes in the volume of the liquid within the contact lens packaging. The method may include any of the various features disclosed herein, including one or more embodiments of the following implementations.

[0048] Implementation Scheme 1: A method comprising: introducing a contact lens blister package into a packaging integrity testing unit, wherein the contact lens blister package includes a packaging 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 packaging integrity testing unit includes a linear actuator including an actuation arm; contacting the sealing material with the actuation arm; measuring the deflection of the sealing material; and detecting whether the contact lens blister package contains defects, at least based on the deflection of the sealing material.

[0049] Implementation Scheme 2. The method according to Implementation Scheme 1, wherein the linear actuator includes an electromechanical linear actuator.

[0050] Implementation Scheme 3. The method according to any one of Implementation Schemes 1 to 2, wherein the linear actuator comprises a moving-coil actuator.

[0051] Implementation Scheme 4. The method according to any one of Implementation Schemes 1 to 3, wherein the actuating arm contacts the sealing material with a force in the range of about 0.5 N to about 10.0 N.

[0052] Implementation Scheme 5. The method according to any one of Implementation Schemes 1 to 4, wherein the actuating arm contacts the sealing material such that the sealing material of the complete blister package is deflected by an amount of about 5 micrometers to about 100 micrometers.

[0053] Implementation Scheme 6. The method according to any one of Implementation Schemes 1 to 5, wherein the actuating arm contacts the sealing material for a period of about 1 second to about 1 minute.

[0054] Implementation Scheme 7. The method according to Implementation Scheme 6, wherein detecting whether the contact lens blister packaging is defective based at least on the deflection of the sealing material comprises: measuring the deflection of the sealing material during the time period, and determining that the contact lens blister packaging contains a defect if the deflection of the sealing material increases during the time period.

[0055] Implementation Scheme 8. The method according to any one of Implementation Schemes 1 to 7, wherein measuring the deflection of the sealing material comprises: using one or more Hall effect sensors in the linear actuator to determine the position of the actuator arm.

[0056] Implementation Scheme 9. The method according to any one of Implementation Schemes 1 to 8, wherein measuring the deflection of the sealing material comprises: using one or more linear encoders in the linear actuator to determine the position of the actuator arm.

[0057] Implementation Scheme 10. The method according to any one of Implementation Schemes 1 to 9, wherein measuring the deflection of the sealing material comprises: measuring using optical microscopy techniques.

[0058] Implementation Scheme 11. The method according to any one of Implementation Schemes 1 to 10, wherein measuring the deflection of the sealing material comprises: measuring using an interferometric technique selected from white light interferometry, phase-shifting interferometry, and combinations thereof.

[0059] Implementation Scheme 12. The method according to any one of Implementation Schemes 1 to 11, wherein detecting whether the contact lens blister packaging contains a defect based at least on the deflection of the sealing material comprises: comparing the measured deflection with a deflection threshold, and determining that the contact lens blister packaging contains a defect if the deflection of the sealing material is greater than the deflection threshold.

[0060] Implementation Scheme 13. The method according to Implementation Scheme 12, wherein the deflection threshold is from about 100 micrometers to about 1500 micrometers.

[0061] Implementation Scheme 14. The method according to any one of Implementation Schemes 1 to 13, wherein the packaging integrity testing unit is part of the contact lens blister packaging production line, and wherein the packaging integrity testing unit is located before and / or after the sterilizer unit in the contact lens blister packaging production line.

[0062] Implementation Scheme 15. A method comprising: introducing a contact lens blister package into a packaging integrity testing unit, wherein the contact lens blister package includes a packaging 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 packaging integrity testing unit includes a moving-coil actuator including an actuator arm; contacting the sealing material with the actuator arm with a force in the range of about 0.5 N to about 10.0 N; measuring the deflection of the sealing material; and detecting whether the contact lens blister package contains defects based at least on the deflection of the sealing material.

[0063] Implementation Scheme 16. The method according to Implementation Scheme 15, wherein the actuating arm contacts the foil, causing the sealing material of the complete blister package to deflect by an amount of about 5 micrometers to about 100 micrometers.

[0064] Implementation Scheme 17. The method according to Implementation Schemes 15 to 16, wherein detecting whether the contact lens blister packaging contains a defect based at least on the deflection of the sealing material comprises: comparing the measured deflection with a deflection threshold, and determining that the contact lens blister packaging contains a defect if the deflection of the sealing material is greater than the deflection threshold.

[0065] Implementation Scheme 18. The method according to Implementation Schemes 15 to 17, wherein the deflection threshold is from about 100 micrometers to about 1500 micrometers.

[0066] Implementation Scheme 19. The method according to Implementation Schemes 15 to 18, wherein the actuating arm contacts the sealing material for a period of about 1 second to about 1 minute.

[0067] Implementation Scheme 20. The method according to Implementation Schemes 15 to 19, wherein detecting whether the contact lens blister packaging is defective based at least on the deflection of the sealing material comprises: measuring the deflection of the sealing material during the time period, and determining that the contact lens blister packaging contains a defect if the deflection of the sealing material increases during the time period.

[0068] To facilitate a better understanding of the present invention, the following embodiments of certain aspects of some implementation schemes are provided. These embodiments should not in any way be construed as limiting or restricting the entire scope of this disclosure. Example

[0069] In this example, linear actuators were used to measure the deflection of the intact foil seal of a blister pack, and contact was made with intentionally defective blister packs. Five defective blister packs were produced by laying an 80-micron line on the surface of the foil seal before heat-sealing the foil seal to the pack base to introduce an 80-micron defect in the seal. The line was then removed. The testing setup consisted of five moving-coil linear actuators configured to apply a constant force to the foil of the blister pack and report the return displacement. The experimental results are as follows: Figure 4 As shown. It was observed that, for the selected force, the intact wireless blister pack had an average displacement of approximately 120 micrometers, while the defective pack base had an average displacement of approximately 1000 micrometers.

[0070] It should be understood that this disclosure is not limited to a specific method, although the method may vary. Furthermore, it should be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. All numerical values ​​and ranges disclosed herein may vary in some quantities. Whenever a numerical range with a lower and upper limit is disclosed, any numerical value falling within that range and any included range is specifically disclosed. Although various embodiments are discussed herein, the invention covers all combinations of all those embodiments. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” include both singular and plural references. Furthermore, the word “may” is used throughout this application in a permissive sense (i.e., potentially, capable) rather than a mandatory sense (i.e., must). The term “comprising” and its derivatives mean “including but not limited to.” The term “connected” means a direct or indirect connection. If the use of words or terms in this specification conflicts in any way with one or more patents or other documents that may be incorporated herein by reference, the definitions consistent with this specification should be adopted for the purposes of understanding the invention.

[0071] For the sake of brevity, this document only explicitly discloses certain ranges. However, a range from any lower limit can be combined with any upper limit to describe a range not explicitly stated, and a range from any lower limit can be combined with any other lower limit to describe a range not explicitly stated, just as a range from any upper limit can be combined with any other upper limit to describe a range not explicitly stated. Additionally, whenever a range of values ​​having a lower and upper limit is disclosed, any value falling within that range and any included range are specifically disclosed. Specifically, each range of values ​​disclosed herein (in the form of “about a to about b” or equivalent “about a to b” or equivalent “from about ab”) should be understood as listing every value and range covered within a broader range of values, even if not explicitly stated. Thus, each point or single value can be used as its own lower or upper limit, combined with any other point or single value or any other lower or upper limit to describe a range not explicitly stated.

[0072] The scope of this disclosure includes any feature or combination of features disclosed herein (explicitly or implicitly), or any generalization thereof, whether or not it alleviates any or all of the problems addressed herein. Various advantages of this disclosure have been described herein; however, embodiments may provide some, all, or no of these advantages, or may provide other advantages.

Claims

1. A method comprising: The contact lens blister pack is introduced into the packaging integrity test unit, wherein the contact lens blister pack includes a packaging base with 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 packaging integrity test unit includes a linear actuator, the linear actuator including an actuator arm; Make the sealing material contact the actuator arm; Measure the deflection of the sealing material; as well as The presence of defects in the contact lens blister packaging is detected at least based on the deflection of the sealing material.

2. The method according to claim 1, wherein, The linear actuator includes an electromechanical linear actuator.

3. The method according to claim 1, wherein, The linear actuator includes a moving-coil actuator.

4. The method according to claim 1, wherein, The actuating arm contacts the sealing material with a force ranging from about 0.5N to about 10.0N.

5. The method according to claim 1, wherein, The actuating arm contacts the sealing material, causing the sealing material of the complete blister pack to deflect by an amount of approximately 5 micrometers to approximately 100 micrometers.

6. The method according to claim 1, wherein, The actuating arm contacts the sealing material for a period of approximately 1 second to approximately 1 minute.

7. The method according to claim 6, wherein, Detecting whether the contact lens blister packaging is defective based at least on the deflection of the sealing material includes: measuring the deflection of the sealing material within the time period, and determining that the contact lens blister packaging contains a defect if the deflection of the sealing material increases within the time period.

8. The method according to claim 1, wherein, Measuring the deflection of the sealing material includes using one or more Hall effect sensors in the linear actuator to determine the position of the actuator arm.

9. The method according to claim 1, wherein, Measuring the deflection of the sealing material includes determining the position of the actuation arm using one or more linear encoders in the linear actuator.

10. The method according to claim 1, wherein, Measuring the deflection of the sealing material includes using optical microscopy techniques.

11. The method according to claim 1, wherein, Measuring the deflection of the sealing material includes using an interferometric technique selected from white light interferometry, phase-shifting interferometry, and combinations thereof.

12. The method according to claim 1, wherein, Detecting whether the contact lens blister packaging contains a defect, at least based on the deflection of the sealing material, includes: comparing the measured deflection with a deflection threshold, and determining that the contact lens blister packaging contains a defect if the deflection of the sealing material is greater than the deflection threshold.

13. The method according to claim 12, wherein, The deflection threshold is approximately 100 micrometers to approximately 1500 micrometers.

14. The method according to claim 1, wherein, The packaging integrity testing unit is part of the contact lens blister packaging production line, and the packaging integrity testing unit is located before and / or after the sterilizer unit in the contact lens blister packaging production line.

15. The method according to claim 1, wherein, The sealing material is a multilayer film.

16. The method according to claim 1, wherein, The sealing material is a multilayer film comprising at least a foil layer and a sealing layer.

17. A method comprising: The contact lens blister pack is introduced into the packaging integrity test unit, wherein the contact lens blister pack includes a packaging base with 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 packaging integrity test unit includes a moving coil actuator, wherein the moving coil actuator includes an actuator arm; The sealing material is brought into contact with the actuator arm by a force ranging from about 0.5 N to about 10.0 N; Measure the deflection of the sealing material; as well as The presence of defects in the contact lens blister packaging is detected at least based on the deflection of the sealing material.

18. The method according to claim 17, wherein, The actuating arm contacts the sealing material, causing the sealing material of the complete blister pack to deflect by an amount of approximately 5 micrometers to approximately 100 micrometers.

19. The method according to claim 17, wherein, Detecting whether the contact lens blister packaging contains a defect, at least based on the deflection of the sealing material, includes: comparing the measured deflection with a deflection threshold, and determining that the contact lens blister packaging contains a defect if the deflection of the sealing material is greater than the deflection threshold.

20. The method of claim 17, wherein, The deflection threshold is approximately 100 micrometers to approximately 1500 micrometers.

21. The method according to claim 17, wherein, The actuating arm contacts the sealing material for a period of approximately 1 second to approximately 1 minute.

22. The method according to claim 21, wherein, Detecting whether the contact lens blister packaging is defective based at least on the deflection of the sealing material includes: measuring the deflection of the sealing material within the time period, and determining that the contact lens blister packaging contains a defect if the deflection of the sealing material increases within the time period.

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