Method and apparatus for selectively controlling contact lens movement during the packaging process

Abstract

A method for selectively controlling movement of a contact lens within a blister package having a cavity, the method comprising the steps of: storing an electric charge at a predetermined location within the cavity, securing the contact lens in the blister package at the location having the electric charge, and, after securing the contact lens, injecting a lens hydration solution into the cavity to hydrate the lens.A method for selectively controlling movement of a contact lens within a blister package having a cavity, the method comprising the steps of depositing droplets of a first lens hydration solution into the cavity, securing the contact lens in the blister package using the droplets, and, after securing the contact lens, injecting a second lens hydration solution into the cavity to hydrate the lens.

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for controlling contact lens movement during the packaging process. [Background technology]

[0002] Current technology for packaging contact lenses involves placing a dry (i.e., unhydrated) hydrophilic lens into the cavity (also called a "well") of an empty blister package. The package typically contains a plurality of separated wells; however, the package may also contain a web of wells.

[0003] After a lens is placed in each well, the package is transported to one or more stations where the lenses are further processed (e.g., inspected or hydrated). After processing, a lid material (e.g., aluminum foil) is added to seal the lens in the cavity, and the lens is sterilized by heating (e.g., by autoclaving).

[0004] If the package contains individual wells, each blister can be sealed with a separate lidstock, or multiple blisters can be sealed with a single sheet of lidstock such that the blisters are connected by the lidstock. The plastic blisters and lidstock form the primary packaging for the lens. Typically, the packaged lens is placed into secondary packaging (e.g., a carton) for sale.

[0005] During transport of the lenses before hydration, the lenses located in the wells are typically subjected to relatively high speed movement between stations, where the lenses are subjected to, for example, substantial acceleration and deceleration, movement around bends, vibration, and / or movement between conveyors by pick-and-place machinery. Because both the lenses and wells are dry, there is little friction to hold the lenses in place, allowing the lenses to move relatively freely around the cavities in the web during transport, especially if the wells are dome-shaped. This results in uncertainty about the position of the lenses during processing, including when liquid is injected into the wells during the hydration step.

[0006] A further source of uncertainty regarding the position of a dry lens within a well arises from the possible presence of random static charges within the well. Such static charges can cause the dry lens to move within the well and / or adhere to the sides of the well. For example, it is common for the well to have a slight negative charge, and the dry lens also to have a slight negative static charge. In such a situation, the lens is repelled by the well, bouncing off the well or "floating" above the well surface, where the lack of friction makes the lens more susceptible to movement. In some instances, to avoid the deleterious effects associated with positional uncertainty, a static neutralizer is used to remove static charges from the well before placing the lens in the well. Summary of the Invention [Problem to be solved by the invention]

[0007] Movement of lenses within the wells presents a quality risk because movement can cause one or more lenses to slide out of the well onto the machine or into adjacent wells during lens transport.

[0008] Another quality risk resulting from lens movement within the well is called eversion, which refers to the lens being "inside out"; i.e., rather than the lens recess being formed on the posterior surface of the lens (to accommodate the posterior surface to the wearer's eye), the recess is formed on the anterior surface. Eversion can occur through multiple mechanisms. For example, transport between stations can cause the lens to invert (i.e., turn inside out) within the well, and subsequent hydration can complete the lens inversion, with the recess being formed on the anterior surface. Alternatively, forces associated with the injection of purified water or saline can cause the lens to evertip if movement or static electricity causes the lens to rise up the wall of the well.

[0009] Further complicating quality control of the lens packaging process is the fact that it can be difficult or impossible to detect when a lens is in an inverted state using conventional machine vision equipment. Lenses that are subjected to sterilization while in an inverted state will have their dimensions permanently changed (e.g., the lens will become flatter and wider), which can create lens performance issues and / or wearer comfort issues. [Means for solving the problem]

[0010] According to an embodiment of the present invention, the lens is temporarily attached to a well formed in the packaging material using static electricity or a liquid. Typically, the attachment location is the center of the well (e.g., the center of a dome-shaped well). The attachment itself reduces or eliminates lens movement during the packaging process, increasing positional certainty during the packaging process. Furthermore, if movement does occur, because the lens starts in a central location, the movement is less likely to pose a quality risk.

[0011] An aspect of the present invention is directed to a method for selectively controlling movement of a contact lens within a blister package having a cavity, the method comprising the steps of storing an electric charge at a predetermined location within the cavity, securing the contact lens in the blister package at the location with the electric charge, and, after securing the contact lens, injecting a lens hydration solution into the cavity to hydrate the lens and terminate the securing.

[0012] In some cases, the charge accumulation step is accomplished using a first electrode and a second electrode on opposite sides of the cavity, one of the electrodes being a ground electrode, and the accumulated charge being a negative charge.

[0013] In some examples, one of the electrodes is a negative electrode, and the negative electrode is located above a concave surface that defines a cavity. The cavity may be dome-shaped.

[0014] In some examples, accumulating charge includes forming a linearly varying voltage signal between the electrodes, while in other examples, accumulating charge includes forming a constant magnitude voltage between the electrodes.

[0015] The location may be a central location. Accumulation may be achieved using an electrostatic charging device.

[0016] In some examples, the method further includes sealing the cavity containing the contact lens and hydration solution with a lid material, and autoclaving the packaged lens and hydration solution after the sealing step.

[0017] Another aspect of the invention relates to a packaged contact lens that includes a blister package with a cavity having a contact lens fixed in a central position in the cavity by an electric charge.

[0018] Yet another aspect of the present invention is directed to a method for selectively controlling movement of a contact lens within a blister package having a cavity, the method comprising depositing a droplet of a first lens hydration solution within the cavity, securing the contact lens in the blister package using the droplet, and, after securing the contact lens, injecting a second lens hydration solution into the cavity to hydrate the lens.

[0019] In some cases, the liquid is one of saline or purified water. The liquid may include alcohol.

[0020] The droplet may be deposited at a central location.

[0021] In some instances, the second lens hydration solution is the same as the first lens hydration solution.

[0022] In some instances, the step of injecting the second lens hydration solution occurs after the droplet has evaporated to the point where the lens is no longer secured by the droplet.

[0023] In some cases, the step of injecting the second lens hydration solution occurs before the droplet evaporates to a point where the droplet no longer secures the lens, thereby causing the step of injecting the second lens hydration solution to terminate the fixation of the contact lens.

[0024] In some examples, the method further includes sealing the cavity containing the contact lens and hydration solution with a lid material, and autoclaving the packaged lens and hydration solution after the sealing step.

[0025] Yet another aspect of the present invention relates to a packaged contact lens comprising a blister package with a cavity having a contact lens secured therein by about 40-45 mL of lens hydration solution.

[0026] In some instances, the lens hydration solution is purified water.

[0027] As used herein, the term "central location of a well (or cavity)" is defined to mean within about 15 percent of the radial distance from the center of the well to the edge of the well, measured in a plane parallel to a plane containing the edge of the well (i.e., the largest outer dimension of the contour forming the well), and in some instances, to mean within about 10 percent of the radial distance from the center of the well to the edge of the well.

[0028] These and other aspects of the present invention will become evident upon reference to the following detailed description and appended claims.

[0029] Exemplary, non-limiting embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which the same reference numerals are used to designate the same or similar components in different figures. [Brief explanation of the drawings]

[0030] [Figure 1A] 1 is a series of schematic diagrams illustrating an example of an apparatus and process for selectively controlling movement of a contact lens within a blister package with a cavity, according to an aspect of the present invention. [Figure 1B] 1 is a series of schematic diagrams illustrating an example of an apparatus and process for selectively controlling movement of a contact lens within a blister package with a cavity, according to an aspect of the present invention. [Figure 1C] 1 is a series of schematic diagrams illustrating an example of an apparatus and process for selectively controlling movement of a contact lens within a blister package with a cavity, according to an aspect of the present invention. [Figure 2A] 1 is a series of schematic diagrams illustrating another embodiment of an apparatus and process for selectively controlling movement of a contact lens within a blister package, in accordance with an aspect of the present invention. [Figure 2B]1 is a series of schematic diagrams illustrating another embodiment of an apparatus and process for selectively controlling movement of a contact lens within a blister package, in accordance with an aspect of the present invention. [Figure 2C] 1 is a series of schematic diagrams illustrating another embodiment of an apparatus and process for selectively controlling movement of a contact lens within a blister package, in accordance with an aspect of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Aspects of the present invention are further described with reference to the following specific examples, which are provided by way of illustration and are understood to be in no way intended to limit the claimed invention beyond the language set forth in the claims.

[0032] 1A-1C are a series of schematic diagrams illustrating an example of an apparatus and process for controlling the movement of contact lenses 50a-50d within a blister package 100 containing cavities 102a-102d, according to an embodiment of the present invention. For example, each diagram may correspond to a station where contact lenses (also referred to herein simply as lenses) are processed during the packaging process. While three processes are illustrated, one or more inspection or other processes may occur before, after, or between the illustrated processes. While four lenses in four wells are shown, according to an embodiment of the present invention, a process may be applied to one or more lenses. The blister package 100 may be formed of separate pieces, each having a single well (as shown) or a web of connected wells.

[0033] As shown in FIG. 1A, charge accumulates at a location within the cavity (i.e., on the concave surface defining the cavity). For example, relatively negative and positive electrodes 104a-104d, 104a'-104d', are positioned on opposite sides of the well; a voltage sufficient to generate an arc between the electrodes is applied. In some cases, it may be advantageous for one of the electrodes to be a ground electrode. Typically, charge accumulates at a central location within each well; however, charge may accumulate at any location deemed to pose an appropriately low quality risk.

[0034] When an arc occurs, a charge C accumulates on the surface of each well 102a-102d as the arc passes through the well and ionizes the area. As discussed below, it will be understood that the accumulated charge can be negative or positive, depending on the electrode configuration. Due to the insulating properties of the plastic that makes up wells 102a-102d, the charge remains localized in close proximity to the location where the arc formed. For example, the blister package can be made from polypropylene, polyethylene, polyvinyl chloride, or polystyrene.

[0035] In the illustrated embodiment, negative electrodes 104a-104d are positioned above (and spaced apart from) their corresponding wells 102a-102d, and ground electrodes 104a'-104d' are positioned below (and in contact with) their corresponding wells. In particular, in the illustrated embodiment, the ground electrodes are provided by a conductive (e.g., metal) pallet 110 on which the blister packs are placed and connected to electrical ground. Because the wells 102a-102d are dome-shaped, the ground electrodes may contact each of the wells at substantially a single point; alternatively, the blisters are not in contact with the metal pallet but are close enough for an arc to occur through the blister material. Thus, when electrodes 104a-104d are lowered into the wells (e.g., to 4-15 mm above the bottom of the well), an arc forms between the electrodes, and a charge builds up at the bottom of each well.

[0036] For example, in some embodiments, to accumulate charge, a voltage signal is formed between the positive and negative electrodes associated with each well, and the voltage signal varies linearly between -20 kV and +20 kV (kilovolts) over a period of 500 mS (milliseconds). After the charge has accumulated, the electrodes 104a-104d are moved out of the well and the blister is moved to another station. Alternatively, a fixed voltage can be applied by the electrodes. For example, a fixed voltage of -14 kV can be used over a period of 300-400 mS to form an arc. For example, the resulting arc can be approximately 5 mm. 2 In some embodiments, charge present on the package (e.g., random charge generated during manufacturing) is neutralized before the charge can accumulate due to arcing.

[0037] In addition to the voltage setting of the ionizer, the strength of the bond between the contact lens and the well is also affected by the charge on the contact lens itself, allowing for several different scenarios. Some contact lens designs tend to be positively charged (0.3 kV) after manufacture, and therefore achieve stronger blister adhesion when the blisters are negatively charged. For example, if a contact lens has a charge of +6 kV on its surface and the blister well is given a charge of -6 kV, the lens is expected to have a moderately strong adhesion to the well. If the lens is negatively charged, applying a positive charge to the blister will result in better adhesion. However, it will be understood that if the contact lens is negatively charged to -6 kV and the blister well is given a charge of -6 kV, the well is expected to repel the lens. It should also be understood that if no charge exists on the lens (e.g., the charge is neutralized), the well can be given either a positive or negative charge to provide adhesion.

[0038] It is understood that the polarity and strength of the voltage present on the lens will depend on the design and manufacture of the lens. For example, an uncontrolled ion cloud may exist inside the machine enclosure in which the lens is manufactured as a result of a malfunctioning anti-static device, or may be the result of a charge source. The polarity and strength of the charge provided to the well using such a system can be selected based on the type of lens or blister or the automation in use.

[0039] Examples of devices that can be used to store charge are summarized as follows (all manufactured by SIMCO-Ion, Technology Group of Hatfield, PA USA): Performax IQ Easy for neutralizing static surfaces IML spider electrode and pin assembly for delivering an arc to the surface IML SPIDER Charge Distribution Module CMM IQ Easy for generating electric charges · Manager IQ Easy, a human-machine interface for managing charge processes.

[0040] Devices with one or more electrodes for accumulating charge are commonly referred to as electrostatic charging devices or surface ionization devices. In some examples, electrodes 104a-104d are electrically connected to one another via a charge distribution module (e.g., an IML Spider), as shown, to facilitate uniform distribution of charge to the cavity. While the techniques described above represent some options for accumulating localized charge on a plastic material, any suitable technique may be used.

[0041] As shown in FIG. 1B, contact lenses 50a-50d are temporarily secured in blister package 100 at positions bearing an electrical charge C. The lenses can be loaded into the wells using any suitable conventional technique (e.g., manually or automated). Once the lenses are loaded into wells 102a-102d, they adhere to the charged positions. In some instances, it has been found that the electrical charge is sufficient to allow the lenses to remain secured in the wells even when the blister pack is inverted (i.e., upside down) and shaken; however, any suitable amount of electrical charge may be used to reduce the risk of migration to a suitable level. It will be appreciated that lenses secured by electrical charge can be transported between stations during the packaging process with reduced risk of quality issues.

[0042] As shown in FIG. 1C, after the step of placing contact lenses 50a-50d (shown in FIG. 1B) is completed and after any high-risk transport, lens hydration solution L is injected into the cavities, thereby hydrating and securing lenses 50a-50d (fabricated with conventional hydrophilic materials). That is, conventional lens hydration solution (e.g., saline or purified water) is applied to the wells from nozzles 106a-106d in a conventional manner and in a conventional amount for packaging lenses, dissipating the local charge and thereby releasing the lenses from the cavity walls. Importantly, application of the hydration solution releases the lenses from the well surfaces, and the lenses within the packages behave as if no charge had been applied.

[0043] 2A-2C are a series of schematic diagrams illustrating another embodiment of an apparatus and process for controlling movement of contact lenses 50a-50d within a blister package 100 according to an embodiment of the present invention.

[0044] As shown in FIG. 2A, droplets D of a first lens hydration solution are deposited into cavities 102a-102d by nozzles 202a-202d. The droplet volume is approximately 40-45 mL (milliliters) of liquid. The droplet volume is selected so that the lenses 50a-50d are not so large that they float on the liquid (separated from the well walls), nor so small that they do not remain adhered to the well walls. The liquid can be safe for application to the wearer's eye or one that evaporates before the lens is applied to the wearer's eye. For example, the hydration solution can be purified water, saline, or an alcohol such as isopropyl alcohol. Typically, the droplets are deposited in a central location within each well; however, the droplets can be deposited in any location deemed appropriate and pose a risk of poor quality. In some examples, nozzles 202a-202d are fluidly coupled to one another as shown, facilitating the delivery of droplets to multiple cavities or webs of cavities.

[0045] As shown in FIG. 2B, contact lenses 50a-50d are secured to blister package 100 by droplet D, which is shown spreading across the lens and well walls. Lenses 50a-50d may be loaded into cavities 102a-102d using any suitable conventional technique (e.g., manually using a tool or in an automated manner). Once the lens is loaded into the well, it adheres to the well walls, likely due to adhesive properties of the liquid within the lens to the liquid on the walls and / or cohesive forces between the liquid and the plastic. Furthermore, as water is absorbed by the lens, the lens shape changes (locally at the location where the water is absorbed) and the lens has a larger contact area with the well, which may add to the lens's resistance to movement.

[0046] As shown in FIG. 2C, after the process of placing contact lenses 50a-50d is completed and after any high-risk transport, a second lens hydration solution is injected into cavities 102a-102d. Application of the second lens hydration solution by nozzles 106a-106d can be accomplished using a conventional lens hydration solution (e.g., saline or purified water) in a conventional manner and in a conventional amount for packaging contact lenses. The second lens hydration solution is applied in an amount that allows the lens (manufactured from a conventional hydrophilic material) to absorb the second hydration solution, which terminates the cohesive / adhesive properties achieved by droplet D and releases lenses 50a-50d from the well walls. The first and second lens hydration solutions may be the same or different from each other. Importantly, application of the hydration solution does not functionally alter the lens; the lens within the packaging behaves as if droplet D had not been applied.

[0047] It should be understood that the hydration liquid droplets evaporate over time. Therefore, any transport of the lenses 50a-50d that occurs with the lenses adhering to the walls of the cavities 102a-102d should occur before substantial evaporation of the droplets so that the lenses remain sufficiently fixed to the cavity walls during transport. In some examples, according to the present invention, the droplets may be allowed to completely evaporate after transport and before injection of a second lens hydration liquid if the risk of lens movement within the well associated with injection of liquid (into a well containing a dry lens) is deemed sufficiently low. It should be understood that the amount of liquid in the droplets and the ambient air conditions (which affect evaporation) allow for control of droplet evaporation and, therefore, selective control of lens movement. However, it should be noted that if the second hydration liquid is injected before substantial evaporation of the first hydration liquid, the step of injecting the second lens hydration liquid into the cavity will hydrate and complete fixation of the lenses 50a-50d.

[0048] While various embodiments have been shown and described in detail herein, it will be apparent to those skilled in the art that various modifications, additions, substitutions, and the like, can be made without departing from the spirit of the invention and are therefore considered to be within the scope of the invention as defined in the claims that follow.

[0049] Further embodiments of the present invention are defined in the following clauses: Item 1: A method for selectively controlling movement of a contact lens within a blister package having a cavity, comprising: storing an electric charge at a predetermined location within the cavity; securing the contact lens in the blister package at the charged location; and a step of injecting a lens hydration solution into the cavity after the step of fixing the contact lens, whereby the lens is hydrated and fixing is completed; A method comprising: Item 2: The method of item 1, wherein the step of accumulating the charge is accomplished using a first electrode and a second electrode on either side of the cavity. Item 3: The method of item 2, wherein one of the electrodes is a ground electrode. Item 4: The method according to Item 1, wherein the charge is a negative charge. Item 5: The method according to item 2, wherein one of the electrodes is a negative electrode, and the negative electrode is located above the concave surface that defines the cavity. Item 6: The method of item 1, wherein the cavity is dome-shaped. Item 7: The method of item 2, wherein the step of accumulating charge includes forming a linearly varying voltage signal between the electrodes. Item 8: The method according to Item 2, wherein the step of accumulating charge includes the step of forming a voltage of a certain magnitude between the electrodes. Item 9: The method of item 1, wherein the location is a central location. Item 10: The method of item 1, wherein the accumulation is achieved using an electrostatic charging device. Item 11: sealing the cavity containing the contact lens and hydration solution with a lid; and autoclaving the packaged lenses and hydration solution after said sealing step. Item 1, the method of claim 1 further comprising: Item 12: A packaged contact lens comprising a blister package with a cavity having a contact lens fixed in a central position in the cavity by an electric charge. Item 13: A method for selectively controlling movement of a contact lens within a blister package having a cavity, comprising: depositing a droplet of a first lens hydration solution within the cavity; securing the contact lens in the blister package with the droplet; and after the step of fixing the contact lens, injecting a second lens hydration solution into the cavity to hydrate the lens. A method comprising: Item 14: The method of item 13, wherein the liquid is one of saline or purified water. Item 15: The method according to Item 13, wherein the liquid comprises alcohol. Item 16: The method of item 13, wherein the droplet is deposited at a central location. Item 17: The method of Item 13, wherein the second lens hydration solution is the same as the first lens hydration solution. Item 18: The method of item 13, wherein the step of injecting the second lens hydration solution occurs after the droplets have evaporated to a point where the lens is no longer secured by the droplets. Item 19: The method of item 13, wherein the step of injecting the second lens hydration solution occurs before the droplet evaporates to a point where the droplet no longer secures the lens, thereby completing the fixation of the contact lens. Item 20: sealing the cavity containing the contact lens and hydration solution with a lid; and autoclaving the packaged lenses and hydration solution after the sealing step. Item 14. The method of item 13, further comprising: Item 21: A packaged contact lens, comprising a blister package with a cavity, the cavity having a contact lens secured therein by about 40-45 mL of lens hydration solution. Item 22: The packaged contact lens of item 21, wherein the lens hydration solution is purified water.

Claims

1. 1. A method for selectively controlling movement of a contact lens within a blister package having a cavity, comprising: storing an electric charge at a predetermined location within the cavity; securing the contact lens in the blister package at the charged location; and a step of injecting a lens hydration solution into the cavity after the step of fixing the contact lens, whereby the lens is hydrated and fixing is completed; A method comprising:

2. 2. The method of claim 1, wherein said storing charge is accomplished using a first electrode and a second electrode on opposite sides of said cavity.

3. 3. The method of claim 2, wherein one of the electrodes is a ground electrode.

4. The method according to any one of claims 1 to 3, characterized in that the charge is a negative charge.

5. 4. The method of claim 2 or 3, wherein one of the electrodes is a negative electrode, the negative electrode being located above a concave surface that defines the cavity.

6. The method according to any one of claims 1 to 5, characterized in that the cavity is dome-shaped.

7. A method according to any one of claims 1 to 6, characterized in that the step of accumulating charge comprises forming a linearly varying voltage signal between the electrodes.

8. The method according to any one of claims 1 to 7, wherein the step of storing the charge includes the step of forming a voltage of a certain magnitude between the electrodes.

9. A method according to any one of claims 1 to 8, characterized in that said location is a central location.

10. A method according to any one of claims 1 to 9, characterized in that the accumulation is achieved using an electrostatic charging device.

11. sealing the cavity containing the contact lens and hydration solution with a lid; and autoclaving the packaged lenses and hydration solution after said sealing step. The method according to any one of claims 1 to 10, further comprising:

12. 1. A packaged contact lens comprising a blister package having a cavity with a contact lens fixed in a central position of the cavity by an electric charge.

13. 1. A method for selectively controlling movement of a contact lens within a blister package having a cavity, comprising: depositing a droplet of a first lens hydration solution within the cavity; securing the contact lens in the blister package with the droplet; and after the step of fixing the contact lens, injecting a second lens hydration solution into the cavity to hydrate the lens. A method comprising:

14. 14. The method of claim 13, wherein the liquid is one of saline or purified water.

15. 14. The method of claim 13, wherein the liquid comprises alcohol.

16. A method according to any one of claims 13 to 15, characterized in that the droplet is deposited at a central location.

17. A method according to any one of claims 13 to 16, characterized in that the second lens hydration solution is the same as the first lens hydration solution.

18. 18. The method of any one of claims 13 to 17, wherein the step of injecting the second lens hydration solution occurs after the droplet has evaporated to the point where it no longer secures the lens.

19. 19. The method of any one of claims 13 to 18, wherein the step of injecting the second lens hydration solution is performed before the droplet evaporates to a point where the lens is no longer fixed by the droplet, thereby completing the fixation of the contact lens.

20. sealing the cavity containing the contact lens and hydration solution with a lid; and autoclaving the packaged lenses and hydration solution after the sealing step. The method according to any one of claims 13 to 19, further comprising:

21. 1. A packaged contact lens comprising a blister package having a cavity, the cavity having a contact lens secured therein by about 40-45 mL of lens hydration solution.

22. 22. The packaged contact lens of claim 21, wherein the lens hydration solution is purified water.

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