Patent Abstract:
Extraneous liquid is absorbently removed from the rim or sealing area of a contact lens package prior to sealing it, so as to promote good adhesion of the foil cover to the rim when the package is sealed. As the package moves through the system, the package rim and an absorbent blotter are moved into contact with one another. The blotter absorbs any extraneous liquid on the rim. A vacuum or other dryer can be included to further remove the absorbed liquid from the blotter.

Full Description:
[0001]    This application claims the benefit under 35 USC §119 (e) of U.S. provisional application Ser. No. 61/373,023 filed on Aug. 12, 2010, incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates generally to the packaging of ophthalmic contact lenses and, more specifically, to promoting good sealing of the contact lens package. 
         [0004]    2. Description of the Related Art 
         [0005]    As shown in  FIGS. 1-2 , hydrophilic ophthalmic contact lenses are commonly packaged in individual packages  10 , generally known as “blister packages” or “blister packs.” A blister pack generally consists of a plastic (e.g., polypropylene) shell  12  having a bowl-shaped depression or cavity  13  in which a lens (not shown) is disposed immersed in a sterile aqueous solution (not shown) and sealed with a laminate foil cover  14 . A flat rim  16  surrounds the cavity  13 . (Shells  12  may include additional features to aid use and handling, but they are not shown for purposes of clarity.) As shown in  FIG. 2 , blister packages are generally manufactured in strips comprising a number, such as five, of adjoining blister packages that a user can easily separate by snapping them apart from one another. Such packaging keeps the lens in a hydrated and sterile state before being opened and worn by a user. Often, a lens is contained within a blister package for a significant amount of time while the lens is being shipped and held in storage before use. Therefore, it is important that the aqueous solution be hermetically sealed therein, to ensure that the solution cannot leak out and to prevent contaminants from entering the lens containment area. In one method of hermetically sealing the laminate foil to the plastic shell, a heating element or heated seal plate presses the laminate foil against the rim  16  to heat-seal the foil cover  14  to the shell. 
         [0006]    Undesirable conditions during sealing can sometimes give rise to a poor, i.e., non-hermetic, seal between the foil cover  14  and the plastic shell  12 . For example, droplets or moisture between the cover and seal area can create wrinkles in the foil cover and/or prevent the foil cover from properly adhering to the shell. These conditions can create undesired channels or pathways between the foil and bowl that can permit the aqueous solution to leak out of the blister package or contaminants to infiltrate the lens area. 
         [0007]    Accordingly, needs exist for improvements to contact lens packaging systems that promote good, i.e., hermetic, seals between the cover and plastic shell of a blister package. The present invention is directed to these needs and others in the manner described below. 
       SUMMARY 
       [0008]    The present invention relates to a system and method for absorbently removing (such as by absorbent blotting) of extraneous liquid from the rim or sealing area of a contact lens package prior to sealing it, so as to promote adhesion of the foil cover to the rim when the package is sealed. In some embodiments of the invention, an absorbent blotter may be moved into contact with the rim of a contact lens package. In other embodiments, the contact lens package may be moved into contact with an absorbent blotter. In still other embodiments, both the contact lens package and absorbent blotter can move. For example, a conveyor can advance the contact lens packages toward a blotting position. In coordination with the advancement of a contact lens package into the blotting position, an actuator can extend the absorbent blotter into contact with the rim. 
         [0009]    In some embodiments, the system can include a liquid-detecting sub-system for detecting moisture or a droplet on the rim and trigger the blotting or absorbent removing of liquid to occur only when such liquid is detected. 
         [0010]    In some embodiments, the system can include a dryer subsystem for removing liquid from the absorbent blotter. The dryer can include a vacuum for removing liquid by suction. Alternatively or in addition, heating, wiping, squeezing, or other means for removing liquid from the absorbent blotter can be employed. 
         [0011]    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 embodiments of the invention are exemplary and explanatory only, and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a side elevation view of a blister pack in accordance with the prior art, showing the foil cover over the rim of the shell. 
           [0013]      FIG. 2  is a top view of a strip of blister pack shells in accordance with the prior art. 
           [0014]      FIG. 3  is a side elevation view of an absorbent system for blotting or wicking extraneous liquid from contact lens packages, such as the blister pack shells of  FIG. 1 , prior to sealing the package, showing the system in a first position, in accordance with one exemplary embodiment of the invention. 
           [0015]      FIG. 4  is similar to  FIG. 3  and shows the system in a second position, as it blots contact lens packages. 
           [0016]      FIG. 5  is a side elevation view of another absorbent system for blotting or wicking or otherwise absorbently removing extraneous liquid from a contact lens package prior to sealing the package, in accordance with another exemplary embodiment of the invention. 
           [0017]      FIG. 6  is a side elevation view of a portion of  FIG. 5 , enlarged to show the ribbon-shaped absorbent blotter in contact with contact lens packages. 
           [0018]      FIG. 7  is a side elevation view of a portion of an absorbent blotter, showing an exemplary layered construction. 
           [0019]      FIG. 8  is a side elevation view of still another absorbent system for blotting or wicking or otherwise absorbently removing extraneous liquid from a contact lens package prior to sealing the package, showing the system in a first position, in accordance with still another exemplary embodiment of the invention. 
           [0020]      FIG. 9  is similar to  FIG. 8  and shows the system in a second position, as it blots a contact lens package. 
           [0021]      FIG. 10  is a flow diagram, illustrating a method for blotting or wicking or otherwise absorbently removing extraneous liquid from a contact lens package prior to sealing it. 
           [0022]      FIG. 11  is a flow diagram, illustrating sub-steps of the method of  FIG. 10 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0023]    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. 
         [0024]    Also, as used in this specification (“herein”) 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 regard to specific combinations of elements described herein, such elements can alternatively be combined in any other suitable manner with each other or with still other elements, and some elements can be omitted, or portions of the elements combined together with portions of other elements to form elements that differ from those specifically described. With regard to specific method steps described herein, unless otherwise stated, the steps can alternatively be performed in sequences other than those specifically described, and some steps can be omitted, or portions of the steps combined together to form steps that differ from those specifically described. Persons skilled in the art to which the invention relates will appreciate that the invention encompasses such alternatives. 
         [0025]    As illustrated in  FIG. 3 , a conveyor has a moving portion  18  (e.g., a belt) that carries contact lens package shells  12  in a direction, indicated by an axis  20  and corresponding arrows, toward a position where successive shells  12  are blotted as described below. Shells  12  are carried in a carrier tray  22  on conveyor moving portion  18 . Carrier tray  22  can be of any suitable design, such as the conventional type commonly used in contact lens manufacturing to carry such shells  12  from one machine or process station to another. For example, such conveyors are commonly used to move a shell  12  from a station at which the lens is placed in the bowl-shaped depression or cavity  13  ( FIG. 1 ) to a station at which the cavity  13  is filled with the aqueous solution, etc. Each carrier tray  22  carries, for example, a conventional strip of five shells  12  (see  FIG. 2 ). The cavities  13  of shells  12  that arrive at the system of  FIG. 3  from such previous stations in the manufacturing process have been filled with a contact lens and the aqueous solution at previous stations (not shown for purposes of clarity). Accordingly, it is possible that during the filling step some of the solution may have splashed upon or otherwise undesirably become disposed upon the rim or area immediately surrounding cavity  13  (sometimes also referred to in the art as the sealing area, as it is this area to which foil cover  14  ( FIG. 1 ) is to be adhered). 
         [0026]    In the embodiment illustrated in  FIG. 3 , an actuator subsystem  24 , which can operate electrically, pneumatically or in any other suitable manner, has a piston-like member  26  with a pad-shaped absorbent blotter  28  attached to its distal end. The term “blotter” is used herein to mean a piece of absorbent material of a suitable size and shape to absorb or wick (e.g., through capillary action) moisture, droplets or other liquid from the rim or sealing area of shell  12 . The term “blotting” is used herein to mean the absorbent or wicking action of a piece of absorbent material to remove liquid. As illustrated in  FIG. 4 , when actuator subsystem  24  is activated, it causes member  26  to extend downwardly, i.e., perpendicularly to axis  20 , (or, alternatively, in other embodiments it could extend in another suitable direction) in a piston-like manner until absorbent blotter  28  contacts the rim of the shell  12  that the conveyor has positioned beneath absorbent blotter  28 , or at least until the blotter contacts a droplet in the sealing area to wick the droplet off of the shell (at the “blotting position”). The contact between absorbent blotter  28  and the rim causes liquid on the rim to be drawn into absorbent blotter  28  by absorption or capillary action. Desirably most or substantially all of such liquid is drawn into the absorbent blotter  28 . After this blotting has been performed, actuator subsystem  24  lifts member  26  or otherwise causes it to retract. The conveyor then advances the next shell  12  to be blotted into the blotting position, and advances the shell  12  that has just been blotted out of the blotting position, in the direction indicated by the arrows and axis  20  in  FIGS. 3-4 . Persons skilled in the art to which the invention relates will appreciate that the actuator mechanism of subsystem  24  can operate in any suitable manner known in the art. For example, in other embodiments it can passively allow gravity to drop absorbent blotter  28  and then actively retract it after blotting. Also, although in the illustrated embodiment, the actuator mechanism moves in a linear manner, in other embodiments it can move in any other suitable manner, such as by rotating an absorbent blotter or portion thereof into contact with a shell  12  in a rotary manner. 
         [0027]    Actuator subsystem  24  optionally includes suitable control electronics that control its activation, and/or can be linked to the operation of other components of the production system. For example, it can activate each time the conveyor advances another shell  12  into the blotting position. Alternatively, it can activate only in response to detection of liquid on the rim of the shell  12 . The liquid detector can comprise a suitable camera system  30  and associated electronic image processing circuitry in subsystem  24 . When the liquid detector detects liquid on the rim of a shell  12 , it signals the actuator to blot that shell  12  in the manner described above. 
         [0028]    A dryer subsystem  32  can also be included for removing liquid from absorbent blotter  28 . Dryer subsystem  32  can comprise, for example, a vacuum or suction pump (not separately shown) that draws liquid by suction from absorbent blotter  28  and deposits the liquid in a collection vessel for disposal. In such an embodiment, the distal portion of member  26  can be a hollow cylinder or have an internal passage, such that the distal end of the cylinder acts as a suction nozzle against the absorbent blotter  28  attached to it. A suitable hose  34  or other conduit can couple the vacuum pump in dryer subsystem  32  to the member interior or passage. Dryer subsystem  32  can include suitable control electronics, in electronic communication with actuator subsystem  24 , to control when the vacuum is activated. For example, it can be activated each time a shell  12  is blotted. Alternatively, it could be activated on a timed basis, such as every few minutes, or on any other suitable basis. It can be activated while a shell  12  is being blotted or, alternatively, between blotting one shell  12  and the next. In other embodiments, the dryer can use means for removing liquid other than or in addition to suction (vacuum), such as heat and/or a fan or blower. 
         [0029]    As illustrated in  FIG. 5 , in another exemplary embodiment, the moving portion  36  of a conveyor like that described above with regard to  FIGS. 3-4  carries shells  12  in carrier trays  38  in the direction indicated by an axis  40  and corresponding arrows, toward a blotting position where shells  12  are blotted by a ribbon-like absorbent blotter  42 . Absorbent blotter  42  is wound about two reels  44  and  46  and guided by suitable guide rollers  48  toward the blotting position. Reel  44  is a supply reel on which a supply of absorbent blotter ribbon  42  is wound in preparation for operation. Reel  46  is a take-up reel that accepts absorbent blotter  42  after having been used in blotting. A suitable actuator  50  drives take-up reel  46  or otherwise causes absorbent blotter  42  to unwind from supply reel  44 , move through the blotting position between reels  44  and  46 , and become wound about take-up reel  46 . Successive shells  12 , carried on trays  38  (e.g., five to a tray), move in coordination with this movement of absorbent blotter  42  such that they successively come into contact with absorbent blotter  42  in an essentially continuous blotting process. The blotter ribbon may be advanced with each successive shell, after blotting a set number of shells, after reaching a predetermined level of moisture saturation, or according to some other protocol. After blotting, shells  12  similarly continue moving in the same direction (e.g., toward another station or process step, as described further below). Note that, alternatively, actuator  50  could be omitted in an embodiment in which absorbent blotter  42  is passively driven by the frictional contact with the rims of shells  12 . In the depicted embodiment, the blotter ribbon advances in a direction parallel to the conveyor direction. In alternate embodiments, the blotter ribbon advances crosswise or perpendicular to the conveyor direction, or obliquely thereto. 
         [0030]    A dryer subsystem  52 , like that described above with regard to  FIGS. 3-4 , can also be included in the embodiment shown in  FIG. 5  for removing liquid from absorbent blotter  42 . Accordingly, a nozzle or similar portion  54  abuts absorbent blotter  42  and is coupled via a suitable hose  56  or other conduit to the vacuum pump (not separately shown) in dryer subsystem  52 . Although portion  54  is shown as abutting absorbent blotter  42  outside of the blotting position, alternatively, it could be disposed inside the blotting position, abutting the surface of absorbent blotter  42  opposite that which contacts shells  12 . In alternate embodiments, the blotter ribbon forms a continuous loop, with successive portions being dried between blotting sequences. 
         [0031]    A portion of the blotting position described above with regard to  FIG. 5  is shown in enlarged form in  FIG. 6  (with carrier tray  38  shown in dashed line for clarity), showing how absorbent blotter  42  contacts a number of the rims of successive shells  12  to blot them of liquid. The blotting position and blotting action for the embodiment shown in  FIGS. 3-4  are essentially the same as in this embodiment ( FIGS. 5-6 ), but the blotting position covers only a single shell  12  in  FIGS. 3-4  whereas the blotting position may cover several shells  12  in this embodiment. Note that features of carrier trays  38 , which can be of any suitable conventional design, such as indexing pins and receptacles for seating shells  12 , are not shown in any figure for purposes of clarity. 
         [0032]    Absorbent blotter  42  is shown in further detail in  FIG. 7 . Note that it can comprise more than one layer, such as an upper layer  58  of non-woven polyester fiber matting bonded to a lower layer  60  (i.e., the layer that contacts shells  12 ) of non-woven ultra-high molecular weight (UHMW) super-absorbent polyester fiber matting. These materials and layered structure are intended only to be exemplary, and persons skilled in the art to which the invention relates will recognize many other suitable materials and arrangements of one or more layers, in view of the teachings herein. Absorbent blotters included in the other embodiments described herein can similarly have any such suitable structure. 
         [0033]    As illustrated in  FIGS. 8-9 , another embodiment can be similar to that described above with regard to  FIG. 5  but which, rather than continuously blotting successive shells  12  as they pass through a multi-shell blotting position, blots shells  12  individually at a single-shell blotting position. The moving portion  62  of a conveyor like that described above with regard to  FIGS. 3-5  carries shells  12  in trays  64  in the direction indicated by an axis  66  and corresponding arrows, toward a blotting position where shells  12  are blotted by a ribbon-like absorbent blotter  68 . Absorbent blotter  68  is wound about supply and take-up reels  70  and  72  and guided by suitable guide rollers  74  in the same manner as described above with regard to  FIG. 5 . A suitable actuator  76  drives take-up reel  72  or otherwise causes absorbent blotter  42  to unwind from supply reel  70 , move through the blotting position, and become wound about take-up reel  72 . 
         [0034]    In some embodiments, movement of the conveyor is indexed, and blotting occurs only when the conveyor halts movement of shells  12 , with a shell  12  in the blotting position. In other embodiments, movement of the conveyor is continuous, and the blotting actuation is timed to the conveyor movement. As in the embodiment of  FIGS. 3-4 , an actuator subsystem  78 , which can operate electrically, pneumatically or in any other suitable manner, has a piston-like member  80 . Note in  FIG. 8  that absorbent blotter  68  is spaced from (and held taut above) the rims of shells  12  before blotting. Then, as illustrated in  FIG. 9 , when actuator subsystem  78  is activated, it causes member  80  to extend downwardly, i.e., perpendicularly to axis  66 , (or, alternatively, in other embodiments it could extend in another suitable direction) in a piston-like manner, and urge a portion of absorbent blotter  68  into contact with the rim of the shell  12  that the conveyor has positioned beneath member  80  at the blotting position, or at least into wicking contact with any droplets thereon. The contact between absorbent blotter  68  and the rim or droplets thereon causes any liquid on the rim to be drawn into absorbent blotter  68  by absorption or capillary (wicking) action. After this blotting has been performed, actuator subsystem  78  lifts member  80  or otherwise cause it to retract. The conveyor then advances the next shell  12  to be blotted into the blotting position, and advances the shell  12  that has just been blotted out of the blotting position. 
         [0035]    Actuator subsystem  78  includes suitable control electronics that control when it activates. For example, it can activate each time the conveyor advances another shell into the blotting position. Alternatively, it can activate only in response to detection of liquid on the rim of the shell  12 . The liquid detector can comprise a suitable camera system  82  and associated electronic image processing circuitry in actuator subsystem  78 . When the liquid detector detects liquid on the rim of the shell  12  then in the blotting position, it signals the actuator to blot the shell  12  in the manner described above. Following blotting, the actuator  76  that drives take-up reel  72  can be signaled to advance absorbent blotter  68  by a suitable amount, such as the length of a single shell  12  (“shell spacing”). Actuators  76  and  78  can thus operate to advance both shells  12  and absorbent blotter  68  in such a coordinated or synchronized manner. 
         [0036]    A dryer subsystem  84 , like that described above with regard to  FIGS. 3-5 , can also be included in the embodiment shown in  FIGS. 8-9  for removing liquid from absorbent blotter  68 . Accordingly, a nozzle or similar portion  86  abuts absorbent blotter  68  at a suitable position along its length and is coupled via a suitable hose  88  or other conduit to the vacuum pump (not separately shown) in dryer subsystem  84 . 
         [0037]    Although only single-conveyor systems are described above for purposes of clarity, it should be understood that the system can include multiple conveyors and blotting systems operating in parallel. 
         [0038]    As illustrated in  FIGS. 10-11 , an exemplary method for removing extraneous liquid using the systems described above can be performed in conjunction with one or more of the process steps or stations of a conventional contact lens manufacturing process line. As these steps are performed, shells  12  are carried in the carrier trays in the manner described above, or otherwise conveyed through the stations or machines at which the process steps are performed. First, the conventional steps  90  and  92  of placing a contact lens (not shown) into a shell cavity and filling the cavity with aqueous solution, respectively, are performed. The steps can be performed continuously, such that successive shells  12  are filled as they pass through the lens placement and solution-filling stations (not shown). At step  94 , the filled shells  12  are optionally conveyed into a station (not shown) that uses ultrasonic vibration to remove any bubbles in the solution, as such bubbles could interfere with optical inspection of the lenses at a subsequent station. Although the ultrasonic bubble remover station is conventional, it is contemplated that the blotting station can be integrated with this station in a suitable manner. Thus, at step  96 , the shells  12  can optionally be blotted in the manner described above in conjunction with vibrational bubble removal. 
         [0039]    As described above, and with further reference to  FIG. 11 , the blotting step  96  can comprise sub-steps  98 ,  100 , and  102  of, respectively: detecting whether there is any liquid on the rim of a shell; bringing the shell and a portion of the absorbent blotter into contact with one another if liquid is detected; and applying a vacuum or otherwise drying a portion of the absorbent blotter to remove some of the liquid. As noted above, the steps can be performed in any suitable order and at any suitable time with respect to each other and other steps. 
         [0040]    Following bubble removal, the conventional step  104  of optically inspecting each lens by imaging the lens through the cavity area of shell  12  using a camera and image-processing equipment (not shown) can be performed. 
         [0041]    At step  106 , shells  12  arrive at a station (not shown) that places the above-described foil covers  14  (see  FIG. 1 ) on them and, at step  108 , seals each cover to the rim in a conventional manner, such as by applying a heat-sealing plate (not shown). The likelihood that a good seal will result is increased because the extraneous liquid is removed, as are contaminants or debris that may have become disposed upon the rims during the filling or other steps described above. 
         [0042]    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. With regard to the claims, no claim is intended to invoke the sixth paragraph of 35 U.S.C. Section 112 unless it includes the term “means for” followed by a participle.

Technology Classification (CPC): 1