Patent Application
20110094898
This application claims foreign priority under 35 U.S.C. §119 of Singapore Patent Application No. 200907048-3 filed Oct. 22, 2009, incorporated by reference in its entirety.
The present invention relates generally to packaging for contact lenses, and more specifically to a contact lens blister pack having a textured interior bowl surface for reducing the incidence of surface chip defects on the contact lens.
Contact lenses are commonly packaged in blister packs. Blister packs come in many different forms, and typically include a container having a concave bowl or cavity formed therein, and a removable cover adhered over the bowl to retain the contact lens and a dose of saline therein and maintain sterility. The contact lens may be subjected to in-container quality assurance inspection while within the bowl of the container.
Surface chip defects can occur on a contact lens when the front curve of the contact lens adheres to the interior surface of the container's bowl, for example, before the saline dosing process or during autoclaving. The adhesion of the contact lens to the container surface may be so great that small chips are torn off of the front face of the contact lens as the lens detaches from the container, creating surface chip defects.
Surface chip defects sometimes result in a lower quality product, reduced efficiency, and increased manufacturing costs. Accordingly, it can be seen that needs exist in the contact lens manufacturing field for reducing the incidence of surface chip defects.
In example embodiments, the present invention relates to an improved container for contact lenses that reduces the incidence and/or severity of surface chip defects. One or more micro-textured patterns applied to regions or zones of the interior surface of the container reduce adhesion of the lens. In example forms of the invention, the regions or zones to which the micro-textured patterns are applied are concentric, adjacent, or otherwise configured relative to one another. Transitions between the micro-textured patterns applied to the regions or zones may be smooth and continuous, or alternatively may be discrete or discontinuous.
In one aspect, the present invention relates to a container for a contact lens. The container includes a cavity for receiving the contact lens, the cavity having an interior surface. At least a portion of the interior surface of the cavity has a micro-textured pattern thereon, wherein the micro-textured pattern is formed of a plurality of microstructures, the microstructures having a substantially rounded dome-like configuration.
In another aspect, the invention relates to a container for a contact lens. The container includes a cavity having an interior surface defining first and second zones of microstructure patterns. The first zone includes microstructures having a first configuration and the second zone includes microstructures having a second configuration, wherein the first configuration is different from the second configuration.
In still another aspect, the invention relates to a method of preventing adherence of a contact lens to a contact lens container, the method including applying a micro-textured pattern to an interior surface of the contact lens container.
In another aspect, the invention relates to a method of manufacturing a contact lens container. The method includes the steps of applying an inverse micro-textured pattern to a mold surface of a mold, and forming the contact lens container in the mold and thereby transferring a mirror image of the inverse micro-textured pattern of the mold surface onto the formed contact lens container.
In another aspect, the invention relates to a method of in-container inspection of a contact lens within a contact lens container. The method includes the steps of capturing an image of the contact lens within the container, and analyzing the image of the contact lens to determine whether it contains a lens defect. The contact lens container has an interior surface with a micro-textured pattern applied thereon, and the micro-textured pattern is not indicated as the lens defect in the analysis of the image.
These and other aspects, features and advantages of the invention will be understood with reference to the drawing figures and detailed description herein, and will be realized by means of the various elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following brief description of the drawings and detailed description of the invention are exemplary and explanatory of preferred embodiments of the invention, and are not restrictive of the invention, as claimed.
The present invention may be understood more readily by reference to the following detailed description of the invention taken in connection with the accompanying drawing figures, which form a part of this disclosure. It is to be understood that this invention is not limited to the specific devices, methods, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the claimed invention. Any and all patents and other publications identified in this specification are incorporated by reference as though fully set forth herein.
Also, as used in the specification including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” or “approximately” one particular value and/or to “about” or “approximately” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment.
With reference now to the drawing figures, wherein like reference numbers represent corresponding parts throughout the several views,
The container 10 comprises a body 12 having a generally concave bowl or cavity 20 formed therein. The bowl or cavity 20 has a smoothly curved inner surface 21 for containing the contact lens and a dose of saline therein. An attachment zone is optionally provided on the body 12 surrounding the bowl 20 for releasably attaching a cover sheet (unshown) over the bowl to retain the lens and saline within the bowl and prevent contamination.
The inner surface 21 of the bowl 20 has a micro-texture pattern 22 applied thereon, an example embodiment of which can be seen more clearly in the microscopic view of
In alternate embodiments, the individual micro-structures can take the form of a concavely recessed cup or bowl, angular peaks or ridges, raised flats, and/or other geometric forms; and may be uniform or non-uniform in configuration and distribution along substantially all of the inner surface 21 of the bowl 20, or along one or more portions of the inner surface of the bowl. Preferably, the micro-texture pattern 22 is applied to the inner surface of the bowl at least in the region of the central, lowermost nadir of the bowl 20. The micro-texture pattern 22 can take different forms, including, but not limited to, a wave-like pattern, a jagged pattern, or a grid-like pattern or the like, each pattern formed of a multiplicity of micro-structures that are replicated along at least a portion of the bowl surface to create the pattern.
Optionally, the micro-structures 24 of the micro-texture pattern 22 have different sizes in different regions of the bowl 20. In an example embodiment, the micro-structures 24 near the center of the bowl 20 have a greater diameter of about 24 μm while the micro-structures nearer the peripheral sides of the bowl have a lesser diameter of about 18 μm. The size change of the micro-structures 24 can be gradual and substantially continuous along the extent of the micro-texture pattern 22, or can change from a greater dimension to a smaller dimension at a sharp pattern transition.
In example modes of manufacture according to the present invention, the container 10 is formed by injection molding in a metal mold. The micro-texture pattern 22 on the container 10 can be formed by application of a mirror-image pattern on the mold, which is then transferred onto the container during the molding process; or alternatively the micro-texture pattern can be directly formed on each container. In particular embodiments, the micro-texture pattern 22 is formed by Electrical Discharge Machining (EDM) of the corresponding mold surface that forms the bowl of the blister pack, by shot-peening (for example using microbeads of glass or other material applied at a high velocity to the mold surface) the mold surface, or by other machining or metal forming methods.
The present invention further comprises a method for performing an In-Package Inspection (IPI) of a contact lens while it is housed within the bowl of a blister pack container. In an example inspection method according to the present invention, a light source is directed towards the blister pack and a camera captures an image of the cavity with the contact lens resting therein using the light source as a backdrop. The light source illuminates any possible surface defects on the contact lens, which images of which are then captured on image by the camera. The top face of the blister pack will be understood to be the view represented by
In order for the IPI to be carried out successfully, a certain amount of light transmittance percentage through the container bowl is desirable, since the IPI process utilizes light to inspect the contact lens. Accordingly, the container is optionally formed of a transparent or translucent material. The specified configurations of the micro-texture pattern on the surface result in relatively little or no negative impact upon the yield and inspection efficiency of the In-Packaging Inspections. More specifically, the light transmittance through the cavity is maintained at a percentage suitable for inspection, even with the presence of the micro texture pattern. Expected adverse effects due to the presence of the micro-texture pattern, such as light scattering or light reflecting, are not found to interfere with the IPI process, and the micro-texture pattern is not recognized as a surface defect. In alternate modes of inspection according to the present invention, computerized inspection algorithms may account for the micro-texture surface pattern and filter it out of the inspection analysis.
While the invention has been described with reference to preferred and example embodiments, it will be understood by those skilled in the art that a variety of modifications, additions and deletions are within the scope of the invention, as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200907048-3 | Oct 2009 | SG | national |
