Abstract:
The present invention discloses a method for cleaning contact lens molds. The method comprises the steps of placing a contact lens mold within an enclosed or substantially enclosed area, directing an inflow of gas under pressure into the enclosed area against the contact lens mold, and providing an outflow of gas from the enclosed area, thereby dislodging and removing debris.

Description:
This application is a division of U.S. Ser. No. 09/409,759 flied Sep. 30, 1999, now U.S. Pat. No. 6,497,000, which claims the benefit under 35 U.S.C. §119(e) of U.S. provisional Application No. 60/186,090 flied Sep. 30, 1998. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to an apparatus for use in manufacturing ophthalmic components, such as contact lenses, and more particularly, to an apparatus for cleaning the molds used to form contact lenses. 
     The manufacture of ophthalmic components, for example contact lenses, is typically carried out in a large number of separate production steps. Very often these production steps must be carried out in an ultra-clean (i.e., inert and sterile) environment such as a “clean room”. Each production step, for example the manufacture and transfer of intermediate components, the positioning of equipment, such as molds, or the operation of equipment, presents an opportunity for contamination of the ophthalmic component. The danger for contamination is especially acute in the manufacture of contact lenses. If the lens manufacturing process is contaminated or corrupted in any way, in most cases the finished lens must be discarded. 
     Contact lenses are generally manufactured in automated or semi-automated production processes. Lens molds consisting of base curve (convex) and front curve (concave) mold halves are transported on carriers through the production process. The molds are symmetrical and are fitted together to form a small crescent shaped mold cavity between the base curve and front curve molds. A lens is formed by introducing a monomer in the front curve mold and then sandwiching the monomer between the base curve and front curve molds. The monomer is then polymerized through heat treatment, light treatment or other polymerizing process, thus forming a lens. The lens is then removed from the molds for further treatment and is packaged for consumer use. 
     If either the base curve or front curve mold is contaminated in any way, the lens formed will contain a flaw, such as an uneven face, and will most likely have to be discarded. Therefore, great care is taken to clean the base curve and front curve molds prior to introducing the monomer to the front curve mold. Currently, the cleaning of the base curve and front curve molds is accomplished manually. Using a hand held compressed gas (i.e. nitrogen) gun, compressed gas is blown over the mold halves to remove any debris that may be present on the surface of the molds. 
     Manual cleaning is an inefficient method by which to clean equipment used in the manufacture of ophthalmic components, especially contact lens molds. Given that the majority of the manufacturing steps involved in the production of contact lenses are automated, the use of any manual cleaning method has the potential to damage equipment, reduce the quality of finished product or at a minimum reduce the efficiency of the overall manufacturing process. For example, lens molds typically travel through the contact lens manufacturing process on carriers which are designed to hold the molds securely throughout the process. If the lens molds are manually cleaned, they are susceptible to becoming misaligned in their carriers or contaminated through inadvertent human contact. A misaligned mold half could form a misaligned lens mold. Misaligned molds result in flawed contact lenses or in manufacturing downtime to either remove or repair the misaligned mold. Similarly, as a result of fatigue or inattention, a technician could inadvertently permit a contaminated mold to proceed through the contact lens manufacturing process, thus resulting in a defective contact lens that could be sold to consumers. 
     The need therefore exists for providing an apparatus for use in the manufacture of ophthalmic components, especially contact lenses, that cleans a desired intermediate component or part to prevent contamination of that part, yet overcomes the above-described disadvantages of manual cleaning methods. In particular, the novel apparatus permits the cleaning of contact lens molds to occur automatically, uniformly and concurrently with other manufacturing steps. The apparatus of the present invention allows for continuous operation, and thus makes more extensive automation of the manufacturing operation possible. 
     OBJECTS OF THE INVENTION 
     It is an object of this invention to provide an apparatus and method for cleaning ophthalmic devices, especially contact lens molds. 
     It is a further object of this invention to provide an apparatus to automate the cleaning of ophthalmic devices, especially contact lens molds. 
     It is a further object of this invention to provide an automated apparatus and method for the cleaning of contact lens molds that increases the efficiency of the contact lens manufacturing process. 
     SUMMARY OF THE INVENTION 
     All of the above and other objects are achieved by an apparatus for the cleaning of ophthalmic components, especially contact lens molds. In its simplest form, the apparatus includes an ophthalmic component carrier, a conveying means, such as a conveyor, for transporting the carrier, and a cleaning station to receive and clean the ophthalmic devices. The cleaning station includes at least one cleaning assembly that is mechanically lowered onto the top of the lens mold carrier. There are recesses formed in the cleaning assembly such that when the cleaning assembly is lowered the recesses and the carrier define a substantially enclosed cavity in which a lens mold is housed. Compressed gas is then injected into the cavity to dislodge any debris that may be on the lens mold. The cavity is subjected to a vacuum to remove any debris that may be present. 
     In a preferred embodiment, the apparatus includes at least one front curve lens mold carrier and at least one base curve lens mold carrier. The front curve lens mold carrier includes a front curve top plate and a front curve bottom plate attached to the top plate. The front curve bottom plate has a plurality of holes and receiving slots formed therein. The receiving slots engage receiving members (e.g. pins) located on the base curve mold to stabilize the mold during monomer polymerization. The front curve top plate also has a plurality of holes formed therein. The top plate holes are in axial alignment with the bottom plate holes thereby providing an opening completely through the carrier when the top plate and the bottom plate are connected to each other. The top plate hole is separated into two sections by a flange. A hollow piston, guided by the flange, travels up and down in the two sections of the top plate hole. The piston is supported by a spring housed in the second section of the top plate hole which rests upon the top surface of the bottom plate. The top plate also has two top plate receiving slots in axial alignment with the bottom plate receiving slots. 
     The preferred embodiment of the apparatus further includes at least one base curve lens mold carrier. The base curve lens mold carrier also has a plurality of holes formed therein. The holes formed in the base curve lens mold carrier are divided into a first (or top) section and a second (or bottom) section with the first section being larger in diameter than the second section. The base curve lens mold carrier also has a channel extending from the edge of the first section to the edge of the carrier which provides rotational alignment for the molds by engaging with a protrusion on the outer diameter of the mold flange. The base curve lens mold carrier also includes two raised receiving members (e.g. pins) which are in axial alignment with the receiving slots formed in the front curve lens mold carrier and which engage with the receiving slots to form a stable mold for manufacturing a contact lens. Preferably, the carriers are transported to the cleaning station on a conventional conveyor. 
     The cleaning station which receives the front curve and base curve lens mold carriers is essentially table-like and includes at least two cleaning assemblies suspended from the underside of the table that can be lowered onto the top of the lens mold carriers. Preferably, the cleaning station consists of four legs and two parallel cross support members attached to the upper portion of the legs. A mounting plate (the table top) is movably attached to both cross support members in a manner that allows the mounting plate to move (i.e. slide) in relation to the cross support members. At least two means for providing vertical movement, such as pneumatic cylinders, are attached to the bottom surface of the mounting plate. At least two connectors for connecting the lens mold cleaning assemblies to the pneumatic cylinders are attached to the bottom of the pneumatic cylinders. 
     At least one front curve lens mold cleaning assembly and one base curve lens mold cleaning assembly are attached to the connectors. Each of the cleaning assemblies includes a top plate, a middle plate, and a bottom plate. The bottom plate of each assembly has a number of recesses corresponding to the number of lens molds carried on the lens mold carrier. The bottom plate recesses are also formed such that they can be in axial alignment with the holes of each carrier. 
     Each of the top, middle and bottom plates has a plurality of holes and recesses arranged to form two channels of fluid communication through the cleaning assembly. In operation, the first channel allows compressed gas to flow through the assembly to be injected into the recesses formed in the bottom plate. The injected gas dislodges any debris that may be present on the lens molds. The second channel of fluid communication allows an external vacuum source to pull the gas and debris out of the recesses. 
     After the front curve and base curve lens molds are cleaned, the cleaning assemblies retract and the conveyor carries the lens mold carriers to subsequent stations in the contact lens manufacturing process. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a preferred embodiment of an apparatus for use in manufacturing ophthalmic components according to the invention; 
     FIG. 2 is a top view of a front curve lens mold carrier; 
     FIG. 3 is a cross-section of the front curve lens mold carrier of FIG. 2 taken along line  3 — 3 ; 
     FIG. 4 is a top view of a base curve lens mold carrier; 
     FIG. 5 is cross-section of the base curve lens mold carrier of FIG. 4 taken along line  4 — 4 ; 
     FIG. 6 is an elevation view of the apparatus of FIG. 1 showing the cleaning assemblies positioned over the lens mold carriers; 
     FIG. 7 is an elevation view showing how the front curve lens mold carrier and the base curve lens mold carrier join to form completed lens molds; 
     FIG. 8 is a top view of the apparatus of FIG. 1 showing the mounting plate moved to the side; 
     FIG. 9 is an end view of the apparatus of FIG. 1 showing the cleaning assemblies positioned over the lens mold carriers with a portion of a cross support member removed for clarity; 
     FIG. 10 is a top view of a front curve mold cleaning assembly according to the invention; 
     FIG. 11 is a cross-section of the front curve mold cleaning assembly of FIG. 10 taken along line  11 — 11 ; 
     FIG. 12 is a cross-section of the front curve mold cleaning assembly of FIG. 10 taken along line  12 — 12 ; 
     FIG. 13 is a top view of a front curve mold cleaning assembly top plate; 
     FIG. 14 is a cross-section of the front curve mold cleaning assembly top plate of FIG. 13 taken along line  14 — 14 ; 
     FIG. 15 is a cross-section of the front curve mold cleaning assembly top plate of FIG. 13 taken along line  15 — 15 ; 
     FIG. 16 is top view of a front curve mold cleaning assembly middle plate; 
     FIG. 17 is a cross-section of the front curve mold cleaning assembly middle plate of FIG. 16 taken along line  17 — 17 ; 
     FIG. 18 is a detailed view of the front curve mold cleaning assembly of FIG. 11 showing channels of fluid communication; 
     FIG. 19 is a top view of a front curve cleaning mold assembly bottom plate; 
     FIG. 20 is a cross-section of the front curve mold cleaning assembly bottom plate of FIG. 19 taken along line  20 — 20 ; 
     FIG. 21 is a cross-section of the front curve mold cleaning assembly bottom plate of FIG. 19 taken along line  21 — 21 ; 
     FIG. 22 is a top view of a base curve mold cleaning assembly according to the invention; 
     FIG. 23 is a cross-section of the base curve mold cleaning assembly of FIG. 22 taken along line  23 — 23 ; 
     FIG. 24 is a cross-section of the base curve mold cleaning assembly of FIG. 22 taken along line  24 — 24 ; 
     FIG. 25 is a top view of a base curve mold cleaning assembly top plate; 
     FIG. 26 is a cross-section of the base curve mold cleaning assembly top plate of FIG. 25 taken along line  26 — 26 ; 
     FIG. 27 is a cross-section of the base curve mold cleaning assembly top plate of FIG. 25 taken along line  27 — 27 ; 
     FIG. 28 is a top view of a base curve mold cleaning assembly middle plate; 
     FIG. 29 is a cross-section of the base curve mold cleaning assembly middle plate of FIG. 28 taken along line  29 — 29 ; 
     FIG. 30 is a top view of a base curve mold cleaning assembly bottom plate; 
     FIG. 31 is a cross-section of the base curve mold cleaning assembly bottom plate of FIG. 30 taken along line  31 — 31 ; 
     FIG. 32 is a cross-section of the base curve mold cleaning assembly bottom plate of FIG. 30 taken along line  32 — 32 ; 
     FIG. 33 is a detailed view of the base curve mold cleaning assembly of FIG. 23 showing channels of fluid communication. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following description, like reference numerals designate like or corresponding parts throughout the several figures. It is to be also understood that such terms as “front”, “rear”, “side”, “up”, and “down” are used for purposes of locating one element relative to another and are not to be construed as limiting terms. Further, it should be understood that the illustrations are for the purpose of describing preferred embodiments of the invention, and thus are not intended to limit the invention in any manner. 
     Referring now to the drawings, FIG. 1, is a perspective view of an apparatus, indicated generally at  10 , for use in the manufacture of ophthalmic components, especially contact lenses. In particular, the apparatus  10  is a cleaning device designed to provide automated cleaning of contact lens molds. Contact lens molds typically have two parts: a front curve lens mold  12  and a base curve lens mold  14 . FIG.  7 . To manufacture a contact lens a polymerizable lens formulation is placed into the front curve lens mold. The base curve mold is then placed in contact with the front curve mold and the polymerizable formulation is allowed to polymerize. 
     The cleaning device  10  has a front curve lens mold carrier  16 , a base curve lens mold carrier  18 , a means for conveying the lens mold carriers  20 , and a cleaning station  22 . Preferably, the cleaning device  10  is designed such that it is capable of cleaning multiple front and base curve lens molds simultaneously. While the embodiment shown in the figures is designed to clean 16 front curve lens molds (2 sets of 8) and 16 base curve lens molds (2 sets of 8) it should be understood that the invention could be easily modified to create a device designed to clean any multiple of front or base lens molds. Similarly, the invention could easily be modified to clean lens molds arranged in circular carriers rather than in the rectangular carriers shown in the figures. The particular embodiment shown in the figures should not be viewed as limiting the scope of the invention or the claims. 
     Overview 
     Referring now to FIG.  1  and FIG. 6, two front curve lens mold carriers  16 , each holding eight front curve lens molds, and two base curve lens mold carriers  18 , each holding eight lens molds, are transported to a cleaning station  22 , by a conveying means  20 . At cleaning station  22  the lens mold carriers are positioned under lens mold cleaning assemblies  24  and  26 . Cleaning assemblies  24  and  26  are lowered and placed in close proximity to the lens molds which are carried by lens mold carriers  16  and  18 . Compressed gas is then blown onto the lens molds to dislodge any debris that may be present, and vacuum is applied to remove any debris. The cleaning assemblies are then retracted and the lens mold carriers proceed to the polymer injection station. The apparatus and process will be discussed in greater detail below. 
     Front Curve Lens Mold Carriers 
     A front curve lens mold carrier (“front curve carrier”) is shown in FIG.  2  and FIG.  3 . The front curve carrier  16 , consists of two plates; a top plate  28 , and a bottom plate  30  which are fixedly attached. Bottom plate  30  contains a plurality of holes  32 , which provide fluid communication through bottom plate  30 . Bottom plate  30  also contains two receiving slots  34 . 
     Top plate  28  having a top and bottom surface, contains a plurality of holes  36 , which provide fluid communication through the top plate  28 . Top plate holes  36 , are in axial alignment with bottom plate holes  32  thereby providing fluid communication through top plate  28  and bottom plate  30 . Top plate holes  36 , have a top (or first) section  38 , having a first outer diameter and a bottom (or second) section  40 , having a second outer diameter smaller than the first outer diameter separated by flange  42 . A channel  44 , extends from first section  38  to the outer perimeter of top plate  28 . Bottom (or second) section  40 , of hole  36  is situated beneath flange  42  and abuts hole  32  thereby creating fluid communication through front curve carrier  16 . The outer diameter of hole  32  is smaller than the outer diameter of bottom (or second) section  40  thereby creating a ledge  46  at the junction of hole  32  and second section  40 . Top plate  28  also contains two receiving slots  34  that are in axial alignment with bottom plate receiving slots  34 . 
     Spring  48  is situated within bottom (or second) section  40  and rests upon ledge  46 . A hollow piston  50 , is situated in the path of travel created by flange  42 . Piston  50  rests upon spring  48  and has freedom of movement through flange  42 . In the absence of tension exerted upon the spring, the top of piston  50  rests slightly above the top of flange  42  as shown in FIG.  3 . When front curve lens mold carrier  16  joins with base curve carrier  18  during lens formation, FIG. 7, spring  48  creates tension between the front curve mold  12  and the base curve mold  14 . 
     Front curve carrier  16  and base curve carrier  18  are joined by engaging front curve locking bar  35 , FIG. 2, with notch  61  in base curve stabilizing member  60 , FIG.  7 . Front curve locking bar  35  travels in front curve top plate locking bar channel  37  which intersects receiving slots  34 . Locking bar  35  contains a semicircular notch  39  with an arc at least equal to that of receiving slot  34 . When notch  39  is aligned with receiving slot  34 , the front curve assembly is in the “open” position and can receive base curve stabilizing member  60 . When stabilizing members  60  are in place, locking bar  35  is moved along locking bar channel  37  such that notch  39  is no longer in alignment with receiving slot  34  thus locking stabilizing member  60  and base curve mold  18  in place. FIG.  7 . Locking bar  35  may be moved by exerting force on attached pin  33 . 
     Base Curve Lens Mold Carriers 
     A base curve lens mold carrier (or base curve carrier) is shown in FIG.  4 . The base curve carrier  18 , is a solid plate having a top and bottom surface. Base curve carrier  18  contains a plurality of holes  52 , which provide fluid communication through base curve carrier  18 . Holes  52  are arranged such that they are in axial alignment with holes  36  when base curve carrier  18  joined with front curve carrier  16 . FIG.  7 . 
     Base curve carrier holes  52 , have a top (or first) section  54 , having a first outer diameter and a bottom (or second) section  56  having a second outer diameter smaller than said first outer diameter. FIG. 5. A channel  58 , extends from first section  54  to the outer perimeter of base curve carrier  18 . 
     Base curve carrier  18  also has two raised stabilizing members  60  which contain notch  61 . FIG.  7 . Raised stabilizing members  60  are in axial alignment with the receiving slots  34  on front curve carrier  16 . As discussed previously, raised stabilizing members  60  engage with receiving slots  34  to form a stable mold during injection and polymerization. 
     Conveying Means 
     The conveying device or means  20  could be any type of conveyor or conveyor belt. In a preferred embodiment, shown in FIG. 9, the conveying means consists of a solid pallet upon which the lens mold carriers are secured and a conveyor which transports the lens molds to cleaning station  22  and on to further processing. 
     The Cleaning Station 
     The cleaning station  22  has a frame, at least one lens mold cleaning assembly (front curve or base curve), and a means for positioning the lens mold cleaning assembly over the lens mold carriers. In a preferred embodiment, shown in FIG.  1  and FIG. 6, the cleaning station frame comprises four legs  66  placed substantially symmetrically about one point. The legs are spaced apart to form an area between the legs sufficient for a conveyor or other conveying means  20  to pass between and through the legs. Cross support members  68  are attached to the legs  66  and are parallel to one another. A mounting plate  70  is movably attached to the cross support members  68 . When connected, the mounting plate  70  the cross support members  68  and the legs  66  form a frame with a generally table like arrangement. 
     Cross support members  68  contain grooves  72  which run longitudinally down the length of cross support members  68  allowing the mounting plate  70  to move in a horizontal fashion relative to cross support members  68 . In the preferred embodiment shown in FIG. 6, mounting plate  70  is fixedly attached to a bracket and bushing assembly  74  which contains three bushings,  76 . The bracket and bushing assembly  74  is attached to the cross support member  68  such that the bushing  76  fits within groove  72 . In this manner the mounting plate  70  may move horizontally with respect to cross support members  68  while remaining attached to cross support members  68 . FIG.  8 . Providing horizontal movement for mounting plate  70  allows easy inspection of the device or lens molds in the event non-optimum operation of the cleaning device is observed. For example, horizontal movement of mounting plate  70  allows an operator access to the mold carriers to reseat misplaced molds as determined by proximity sensors  80 . 
     At least one securing mechanism  78  is provided to secure the position of the mounting plate  70  with respect to the cross support members  68 . The securing mechanism could be a set screw securing the bracket and bushing assembly  74  to the cross support members  68  or any other securing device. In a preferred embodiment shown in FIG.  1  and FIG. 6, the securing mechanism  78  consists of a spring loaded pin that secures mounting plate  70  when pressed down through a hole in cross support member  68 . Proximity sensor  81  is employed to ensure that mounting plate  70  is properly aligned and secured before the cleaning station can be activated. 
     Means for Positioning Mold Cleaning Assemblies 
     Referring now to FIG.  6  and FIG. 8, attached to the bottom surface of mounting plate  70  are a plurality of means for positioning lens mold cleaning assemblies  82 . In the preferred embodiment shown in FIG.  6  and FIG. 8, the means for positioning  82  are four pneumatic cylinders which are attached to a source of compressed gas (not shown). The pneumatic cylinders are arranged substantially symmetrically and attached to the bottom surface of mounting plate  70 . Although the preferred embodiment of the invention utilizes pneumatic cylinders, it is to be understood that any means for providing vertical movement such as hydraulic cylinders, electric motors or mechanical hand cranks may be employed. 
     Front and Base Curve Cleaning Assemblies 
     In a preferred embodiment shown in FIG. 1, FIG. 6, and FIG. 9, four cleaning assemblies are shown: two front curve lens mold cleaning assemblies  24  and two base curve lens mold cleaning assemblies  26 . Each cleaning assembly is connected to pneumatic cylinders  82  by means of a connector  84 . Each front curve and base curve cleaning assembly has three joined plates that allow fluid communication through the plates. 
     Front Curve Cleaning Assembly 
     Referring now to FIG. 10, FIG. 11, and FIG. 12, the front curve cleaning assembly  24  is formed by a top plate  86  a middle plate,  88 , and a bottom plate  90 . The three plates are of approximately equal outer dimension, said dimension being approximately equal to the outer dimension of front curve carrier  16 . In a preferred embodiment, the three plates are generally rectangular and of such a size to allow at least eight symmetrically arranged lens molds to fit within its dimensions. In another preferred embodiment, the shape of the outer dimensions of the three plates is square and the size of plates allows at least sixteen symmetrically arranged lens molds to fit within its dimensions. In operation, the three plates are fixedly attached to is each other, for example, by screws  97  that are placed at the circumferencial edge of the cleaning assembly. 
     Referring now to FIG. 13, FIG. 14, and FIG. 15, a top plate  86  has a top surface  92 , a bottom surface  94 , gas injection hole  96  and vacuum hole  98 . The top plate  86  is attached to connector  84 , as shown in FIG.  9 . The bottom surface  94  contains a milled recess  100 , and the recess has an outer perimeter generally smaller than and symmetrical with the outer perimeter of said top plate  86 , thereby creating an outer ridge  102  along the outer perimeter of the plate. The bottom surface  94  also has a cylindrical island  104 , through which vacuum hole  98  passes to form circular ridge  106 . Ridges  102  and  106  contain channels  108  and  110  respectively, which accommodate O-rings or some other appropriate sealing device. FIG.  12 . The sealing device allows the top plate  86  and the middle plate  88  to be pneumatically sealed. 
     Gas injection hole  96  establishes fluid communication between front curve top plate top surface  92  and recess  100 . Fluid communication between top surface  92  and bottom surface  94  is established by vacuum hole  98 . 
     Referring now to FIG. 11, FIG.  16  and FIG. 17, a front curve middle plate  88  having a top surface  112  and bottom surface  114  is attached to front curve top plate  86  thereby forming a cavity  116  defined by middle plate top surface  112  and the recess  100  of top plate  86 . FIG.  10  and FIG.  18 . O-rings or some other appropriate sealing device seal cavity  116 . Front curve middle plate  88  contains a hole  118  in axial alignment with top plate vacuum hole  98  and of approximately the same diameter as top plate vacuum hole  98 . Hole  118  and vacuum hole  98  provide fluid communication between the top surface of the top plate  92  and the bottom surface of the middle plate  114 . 
     The front curve middle plate  88  also contains a plurality of orifices  120  providing fluid communication between cavity  116  and middle plate bottom surface  114 . In a preferred embodiment, there are eight orifices  120  which are arranged symmetrically. The orifices  120  preferably contain a nozzle  122  or other means to direct the flow of gas through orifice  120 . FIG.  11  and FIG.  18 . Annular extensions  124  which are in axial alignment with orifices  120  and which have an inner diameter approximately equal to the diameter of orifices  120  extend from the middle plate bottom surface  114 . Nozzle  122  and annular extensions  124  direct the flow of compressed gas to the lens molds. FIG.  18 . 
     Referring now primarily to FIG. 19, FIG. 20, and FIG. 21, a front curve bottom plate  90  having a top surface  126  and a bottom surface  128  is attached to front curve middle plate  88 . FIG.  11 . The top surface  126  contains a recess  130  having an outer perimeter generally smaller than and symmetrical with the outer perimeter of the bottom plate  90  thereby creating an outer ridge  132  along the outer perimeter of the plate. Ridge  132  contains channel  134  which accommodates an O-ring or other sealing device. FIG.  12 . The sealing device pneumatically seals the bottom plate and the middle plate when the plates are assembled. When front curve bottom plate  90  is attached to front curve middle plate  88 , a cavity  136  as shown in FIG. 11, FIG.  12  and FIG. 18 is created by recess  130  and middle plate bottom surface  114 . 
     Referring now to FIG. 18, front curve bottom plate bottom surface  128  contains a plurality of raised cylindrical portions  138  having an inner diameter and an outer diameter thereby defining a cylindrical ridge  140  and a cylindrical wall of a recess  142 , situated within cylindrical portion  138 . Optionally, a sealing means, especially an elastomeric sealing means, e.g., o-ring, is attached to the cylindrical ridge  140 , especially at the bottom thereof. Recess  142  extends to a point intermediate top surface  126  and bottom surface  128 . In a preferred embodiment, shown in FIG.  20  and FIG. 21, there are eight raised cylindrical portions  138  symmetrically arranged and in axial alignment with front curve middle plate orifices  120 . 
     A second cylindrical recess  144  having a diameter smaller than the diameter of cylindrical recess  142  extends downward from the bottom of recess  130 . Second cylindrical recess  144  is axially aligned with cylindrical recess  142  and is in fluid communication with cavity  136  and cylindrical recess  142 . Second cylindrical recess  144  is of sufficient diameter to allow middle plate annular extension  124  to substantially occupy recess  144  thereby defining an annular space  146 . Annular space  146  maintains fluid communication between cylindrical recess  142  and cavity  136 . FIG.  18 . 
     Operation of the Front Curve Mold Cleaning Assembly 
     In operation, the front curve mold cleaning assemblies  24  and front curve lens mold carriers  16  are arranged so that cylindrical recesses  142  are in axial alignment with front curve lens mold carrier top plate holes  36 . The front curve cleaning assembly  24  is lowered by positioning means  82  to place the ridge  140  close to the flange of the lens mold  12 , e.g., approximately {fraction (15/1,000)} of an inch from the base of a front curve lens mold, thereby forming a substantially enclosed area. FIG.  18 . Alternatively, especially when the ridge  140  is equipped with sealing means, the front curve cleaning assembly  24  is lowered to place the sealing means of the ridge  140  on the flange of the lens mold  12 , thereby pneumatically sealing the lens mold  12  and the cylindrical recess  142 . 
     Two channels of fluid communication into cylindrical recess  142  are present. The first channel includes hole  96 , cavity  116 , orifices  120 , and annular extensions  124 . The first channel allows an inflow of compressed gas at greater than atmospheric pressure from an outside source (not shown) into cylindrical recess  142  to dislodge any debris residing on the lens mold. The desirable flow rate and/or pressure of the gas impinging on the lens mold may be varied depending on, for example, the effectiveness of the system at removing contaminants. Preferably, the gas is supplied to the cleaning assembly at a pressure of about 15 psi to about 25 psi, more preferably about 20 psi. The compressed gas is filtered before it is applied on the mold to ensure that the gas does not introduce external particulate matters. Gases suitable for the invention include nitrogen, carbon dioxide and air, and desirably, the gas is deionized. FIG.  18 . The second channel of fluid communication is under the influence of a vacuum source or any other device that provides an outflow of gas. Preferably, the outflow device applies between about 1.0 inch of Hg and about 2.0 inches of Hg, more preferably about 1.5 inches of Hg, of vacuum force at the vacuum hole  98  of the cleaning assembly. The second channel is used to remove the gas and debris located in recess  142 . Beginning with recess  142 , the gas and any debris present leave recess  142  via annular space  146  and proceed through cavity  136 , through middle plate vacuum hole  118  and out top plate vacuum hole  98  into a vacuum line (not shown). Gas injection and application of the vacuum can occur independently, simultaneously or sequentially and can be of variable duration. For example, the vacuum is applied first and then quickly the pressurized gas is applied to ensure that all the debris located on the lens mold and in the recess  142  is removed through the annular space  146 . 
     Base Curve Cleaning Apparatus 
     Referring now to FIG. 9, FIG. 22, FIG. 23, and FIG. 24, the base curve cleaning assembly  26  is formed by a top plate  148 , a middle plate  150 , and a bottom plate  152 . The three plates are of approximately equal outer dimension, said dimension being approximately equal to the outer dimension of the base curve lens mold carrier  18 . In a preferred embodiment, the plates are generally rectangular and of such a size to allow at least eight symmetrically arranged lens molds to fit within its dimensions. In another preferred embodiment, the shape of the outer dimensions of the plates is square, and the size of plates allows at least sixteen symmetrically arranged lens molds to fit within its dimensions. In operation, the three plates are fixedly attached to each other, for example, by screws  159  that are placed at the circumferencial edge of the cleaning assembly. 
     Referring now to FIG. 25, FIG. 26, and FIG. 27, a top plate  148  has a top surface  154 , a bottom surface  156 , gas injection hole  158 , vacuum hole  160 , and receiving slots  162 . The top plate  148  is attached to a connector  84 . The bottom surface  156  contains a milled recess  164 , having an outer diameter generally smaller than and symmetrical with the outer perimeter of the top plate  148 , thereby creating a ridge  166  along the outer perimeter of the plate. Ridge  166  contains channel  168  which houses an o-ring or other appropriate sealing device. FIG.  24 . Again, the sealing device forms a pneumatic seal to allow the inflow and outflow of gas are routed through the intended channels when the plates are assembled. The recess also contains raised cylindrical portions  170  and  176  situated in the central portion of bottom surface  156 . Raised cylindrical portions  170  house receiving slots  162  thereby creating cylindrical ridges  172  which contain channels  174 . Channels  174  house o-rings or other appropriate sealing devices. FIG.  26 . 
     Raised cylindrical portion  176  houses vacuum hole  160  thereby creating cylindrical ridge  178  which contains channel  180 . Channel  180  houses an o-ring or other appropriate sealing device. FIG.  24 . 
     Referring now to FIG.  28  and FIG. 29, a base curve middle plate,  150 , having a top surface  182  and bottom surface  184  is attached to the base curve top plate  148 , thereby forming a cavity  186  defined by middle plate top surface  182  and top plate recess  164 . Base curve middle plate  150  contains a hole  188  in axial alignment with base curve vacuum hole  160  and of approximately the same diameter as vacuum hole  160 . Hole  188  and vacuum hole  160  establish fluid communication between the top surface of the base curve top plate  154  and the bottom surface of the base curve middle plate  184 . Base curve middle plate  150  also contains two holes or receiving slots  190  that are in axial alignment and of approximately the same diameter as top plate receiving slots  162 . 
     The base curve middle plate  150  also contains a plurality of orifices  192  providing fluid communication between cavity  186  and middle plate bottom surface  184 . In a preferred embodiment, there are eight orifices  192  which are arranged symmetrically. Orifices  192  preferably contain a nozzle  194 , or other means to direct the flow of gas through orifice  192 , which provides an inflow of compressed gas onto the lens mold that is to be cleaned. FIG.  33 . Annular extensions  196  which are in axial alignment with orifices  192  and which have an inner diameter approximately equal to the diameter of orifices  192  extend from the middle plate bottom surface  184 . 
     Referring now primarily to FIG. 30, FIG. 31, and FIG. 32, a base curve bottom plate  152  having a top surface  198  and a bottom surface  200  is attached to base curve middle plate  150 . FIG.  23 . The top surface  198  contains a recess  202  having an outer perimeter generally smaller than and symmetrical with the outer perimeter of the plate thereby creating an outer ridge  204 . Outer ridge  204  contains a channel  206  which houses an o-ring. FIG.  24 . Within recess  202  are two raised cylindrical portions  208  which house receiving slots  210  thereby creating cylindrical ridges  212 . Ridges  212  contain channels  214 , which house o-rings. FIG.  23 . When base curve bottom plate  152  is attached to base curve middle plate  150 , a cavity  216 , as shown in FIG. 23 is created by recess  202 , and middle plate bottom surface  184 . 
     Base curve bottom plate bottom surface,  200 , contains a plurality of raised cylindrical portions  218  having an inner diameter and an outer diameter thereby defining a cylindrical ridge  220  and the cylindrical wall of a recess  222  having a definite depth situated within cylindrical portion  218 . Optionally, a sealing means, especially an elastomeric sealing means, e.g., o-ring, is attached to the cylindrical ridge  220 , especially at the bottom thereof. Cylindrical recess  222  extends upward into base curve bottom plate  152  to a point intermediate top surface  198  and bottom surface  200 . In a preferred embodiment shown in FIG. 30, there are eight cylindrical portions  218  symmetrically arranged and in axial alignment with base curve middle plate orifices  192 . 
     A second cylindrical recess  224  having a diameter smaller than the diameter of cylindrical recess  222  extends downward from the bottom of recess  202  and is axially aligned with cylindrical recess  222  and establishes fluid communication between recess  202  and cylindrical recess  222 . Second cylindrical recess  224  is of sufficient diameter to allow middle plate annular extensions  196  to substantially occupy recess  222  thereby defining an annular space  226 . Annular space  226  maintains fluid communication between cylindrical recess  222  and cavity  216 . 
     Operation of the Base Curve Cleaning Assembly 
     In operation, base curve mold cleaning assemblies  26  and base curve lens mold carriers  18  are arranged so that cylindrical recesses  222  are in substantially axial with base curve carrier holes  52 . The base curve cleaning assembly  26  is lowered by positioning means  82  to place ridge  218  close to the flange of the lens mold, e.g., approximately {fraction (15/1,000)} of an inch above the base of the lens mold, thereby forming a substantially enclosed area. FIG.  33 . Alternatively, especially when the ridge  218  is equipped with sealing means, the base curve mold cleaning assembly  26  is lowered to place the sealing means of the ridge  218  on the flange of the lens mold, thereby pneumatically sealing the lens mold and the cylindrical recess  222 . Two channels of fluid communication are created. The first channel consisting of hole  158 , cavity  186 , orifices  192  and annular extensions  196  allow compressed gas to flow at greater than atmospheric pressure from an outside source (not shown) into cylindrical recess  222  to dislodge any debris residing on the lens mold. Preferably, the gas is supplied to the cleaning assembly at a pressure of about 15 psi to about 25 psi, more preferably about 20 psi. Gases suitable for the invention include nitrogen, carbon dioxide and air, and desirably the gas is deionized. This flow of gas is shown schematically in FIG.  23  and FIG.  33 . 
     The second channel of fluid communication is under the influence of a vacuum and provides an outflow of gas. Preferably, the outflow device applies between about 1.0 inch of Hg and about 2.0 inches of Hg, more preferably about 1.5 inches of Hg, of vacuum force at the vacuum hole  160  of the cleaning assembly. The channel is used to remove the gas and debris located around the lens mold. Beginning with recess  222 , the gas and any debris present leave cylindrical recess  222  via annular space  226  and proceed through cavity  216  through middle plate hole  188  and out top plate vacuum hole  160  into a vacuum line (not shown). Again, gas injection and application of the vacuum can occur independently, simultaneously or sequentially and can be of variable duration. For example, the vacuum is applied first and then quickly the pressurized gas is applied to ensure that all the debris located on the lens mold and in the recess  222  is removed through the annular space  226 . 
     After the lens molds are cleaned the lens molds proceed to subsequent stations in the lens manufacturing process. 
     The invention has been described in detail, with reference to certain preferred embodiments, in order to enable the reader to practice the invention without undue experimentation. However, a person having ordinary skill in the art will readily recognize that many of the components and parameters may be varied or modified to a certain extent without departing from the scope and spirit of the invention. Furthermore, titles, headings, or the like are provided to enhance the reader&#39;s comprehension of this document, and should not be read as limiting the scope of the present invention. Accordingly, the intellectual property rights to the invention are defined only by the following claims and reasonable extensions and equivalents thereof.