Abstract:
The invention is a mold and method for using the mold to make a multi-stage intraocular lens. The mold is provided with a gate in fluid communication with a lens portion and/or haptic portion of the mold core. In addition, a gasket is provided around the mold core. As molding material is introduced into the mold via the gate, a vacuum is drawn around and through the gasket to evacuate air trapped in the mold core and to help pull the material through the mold core.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    None.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable.  
         APPENDIX  
         [0003]    Not Applicable.  
         BACKGROUND OF THE INVENTION  
         [0004]    1. Field of the Invention  
           [0005]    This invention relates generally to molds and, more particularly, to a mold for a multi-stage intraocular lens.  
           [0006]    2. Related Art  
           [0007]    Multi-lens intraocular lenses have been disclosed in U.S. Pat. No. 6,488,708 B1 issued Dec. 3, 2002 (“the &#39;708 patent”). Prior to the invention disclosed by the &#39;708 patent, lenses were only single stage lenses with haptics going from the lens to muscle tissue. The &#39;708 patent discloses multi-stage lenses that are stacked, with haptics traversing between each lens, connecting each lens together.  
           [0008]    While conceptually an excellent idea, there remains a need in the art to improve the manufacture of such intraocular lenses, such as providing a mold and molding method for making such multi-stage lenses.  
         SUMMARY OF THE INVENTION  
         [0009]    It is in view of the above problems that the present invention was developed. The invention is a mold and molding method for making a multi-stage intraocular lens. Specifically, the mold has a core with lens cavities, haptic cavities, and a gate in direct fluid communication with one or more of the cavities. In addition, the mold is provided with a gasket surrounding the core.  
           [0010]    In use, molding material is flowed through the gate and into the cavities. As the silicone flows into the cavities, a vacuum is drawn around the core and through the gasket. The vacuum evacuates air trapped in the mold core and helps pull the molding material through the mold core.  
           [0011]    Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and together with the description, serve to explain the principles of the invention. In the drawings:  
         [0013]    [0013]FIG. 1 is a perspective view of a multi-stage lens produced by the present invention;  
         [0014]    [0014]FIG. 2 is a perspective view of the mold, mold core, material gate, and gasket of the present invention;  
         [0015]    [0015]FIGS. 3A and 3B are top views of the mold core, illustrating the placement of the gate;  
         [0016]    [0016]FIG. 4 is a side view of the mold core;  
         [0017]    [0017]FIGS. 5A and 5B are perspective views of the mold core sections; and  
         [0018]    [0018]FIGS. 6A and 6B are partial cross-sectional views of the mold core illustrated in FIGS. 3A and 3B, respectively. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    Referring to the accompanying drawings in which like reference numbers indicate like elements, FIG. 1 illustrates a multi-stage intraocular lens, shown generally at  10 , which is produced by the present invention. It is understood that lens  10  is shown with a pair of lenses, but that multi-stage lenses having more than two (2) lenses may be produced by the method of the present invention. The multi-stage lens  10  is provided with an anterior lens  12  and a posterior lens  14  that are connected by a first haptic  16 , second haptic  18  and third haptic  20 . The multi-stage lens  10  is preferably made from silicone. The haptics  16 ,  18 ,  20  are bendable, allowing the lenses  12 ,  14  to be adjusted relative to each other. The haptics  16 ,  18 ,  20  can connect the lenses  12 ,  14  at their periphery  22  or in their interior region  24 .  
         [0020]    Turning now to FIG. 2, a mold, shown generally at  26 , has a mold core  28 , a material flow gate  30 , and a gasket  32 . The mold core  28  has a pair of lens cavities  34 ,  36  that are in communication with each other through haptic cavities  38 ,  40 ,  42 . The gasket  32  surrounds the mold core  28 , including the lens cavities  34 ,  36  and the haptic cavities  38 ,  40 ,  42 . The material flow gate  30  is in communication with any one of more of the cavities in the mold core  28 . Preferably, as illustrated in FIG. 3A, the material flow gate  30  is in communication with one mold core cavity, such as one of the lens cavities  34 ,  36 , and spaced apart from the haptic cavities  38 ,  40 ,  42 . The material flow gate  30  can also be in communication with multiple mold core cavities, including the haptic cavities  38 ,  40 ,  42 . For example, as illustrated in FIG. 3B, the material flow gate  30  is in communication with one of the haptic cavities  38  as well as the lens cavity  36 .  
         [0021]    As illustrated in FIG. 4 and FIGS. 5A and 5B, the mold  26  can be formed by a pair of blocks  44 ,  46  that enclose a center block  48 . FIG. 4 illustrates a side view of the mold core  28  with the center block  48  in place between the pair of blocks  44 ,  46 . FIG. 5A illustrates the inner portion of the block  44  on one side of the mold  26 , and FIG. 5B illustrates the inner portion of the block  46  on the opposite side of the mold  26  together with the center block  48 . The center block is preferably connected to a handle  50  that extends through the blocks  44 ,  46 . The handle  50  is equipped with offset pins  52  that guarantee the proper installation of the center block  48  into the mold  26 , preventing the accidental insertion in a backwards or upside down orientation.  
         [0022]    These views of the mold  26  in FIGS. 4, 5A and  5 B show a particular embodiment of the mold core  28  in which exterior sides of the lens cavities  34 ,  36  are formed as recesses  54 ,  56  in the respective pair of blocks  44 ,  46 . The interior sides of the lens cavities  34 ,  36  are enclosed by opposing sides  58 ,  60  of the center mold  48 . Similarly the exterior sides of the haptic cavities  38 ,  40 ,  42  are formed by haptic recesses  62 ,  64 ,  66  in the pair of blocks  44 ,  46  while their interior sides are enclosed by the circumference  68  of the center mold. It will be appreciated that each one of the haptic recesses  62 ,  64 ,  66  has complementary recessed portions  70 ,  70 ′ in the respective blocks  44 ,  46 . Accordingly, the haptic recesses  62 ,  64 ,  66  in each one of the blocks  44 ,  46  are formed from a pair of partial haptic recesses in the blocks  44 ,  46  (i.e., complementary recessed portions  70 ,  70 ′). The interface between the complementary recessed portions  70 ,  70 ′ should be identical in number, position and shape to reduce the potential for flashing and/or discontinuities in the haptics  16 ,  18 ,  20  during the molding process. The blocks  44 ,  46  fit together snugly at their complementary faces  72 ,  72 ′ through hardware elements  74  that pull the blocks  44 ,  46  together. As particularly illustrated in FIG. 4, the material flow gate  30  is formed by a groove  76  in one of the blocks  44 .  
         [0023]    [0023]FIGS. 6A and 6B illustrate partial cross-sectional views of the mold core  28  according to FIGS. 3A and 3B, respectively. The shape of the haptics  16 ,  18 ,  20  and connection to the lenses  12 ,  14  can be changed through the use of different mold shapes. For example, the haptic cavities  38 ,  40 ,  42  may be in communication with the periphery  78  of a lens cavity  34  or an interior region  80  of a lens cavity  36 . Similarly, the haptic cavities  38 ,  40 ,  42  could have an accordion cross-sectional shape  82 .  
         [0024]    In operation, the pair of blocks  44 ,  46  are locked in place while they enclose the center block  48 . A molding material  84  is flowed through gate  30  into any one or more of the one mold core cavities. Then, a vacuum is applied to the mold core  28  through the gasket  42 . The vacuum evacuates the air from the mold core cavities and assists the molding material  84  in flowing through all of the mold core cavities in the mold core  28 .  
         [0025]    In the preferred embodiment, the molding material  84  is silicone and first flows from the gate  30  into one lens cavity  34  and then flows into the other lens cavity  36  through the haptic cavities  38 ,  40 ,  42 . It will be appreciated that, in an alternative embodiment, a lens  86  (see FIG. 6B) could be made out of a different material and placed in one or both of the lens cavities  34 ,  36 . The lens  86  would at least partially fill one or both of the lens cavities  34 ,  36 , and the molding material could flow around a portion of the lens  86 . For example, the lens  86  could have attachment grooves or orifices where the molding material would lock into the lens  86 . Such alternative lens materials could include polymethylmethacrylate (PMMA), glass, and acrylics. Generally, the molding material can be any type of transparent, pliable material, like silicone and hydrogel. Other possible materials include hydroxyethylmethacrylate (HEMA) and polydimethyl siloxanes.  
         [0026]    In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.  
         [0027]    As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. For example, a multi-stage lens having three stacked lenses separated by three haptics may also be manufactured by the present invention. In such a case, the gate  30  can be placed in direct fluid communication with one lens cavity  34 . Then, material is flowed through gate  30  into the lens cavity  34 . As the vacuum is applied through the gasket  32 , material flows through each of the haptic cavities  38 ,  40 ,  42 , and into the connected lens cavities. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.