Abstract:
Advanced Smart Cards and similar form factors (e.g. documents, tags) having high quality external surfaces of Polyvinylchloride (PVC), Polycarbonate (PC), synthetic paper or other suitable material can be made with highly sophisticated electronic components (e.g. Integrated Circuit chips, batteries, microprocessors, Light Emitting Diodes, Liquid Crystal Displays, polymer dome switches, and antennae), integrated in the bottom layer of the card structure, through use of injection molded thermosetting or thermoplastic material that becomes the core layer of said Advanced Smart Cards. A lamination finishing process can provide a high quality lower surface, and the encapsulation of the electronic components in the thermosetting or thermoplastic material provides protection from the lamination heat and pressure.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to advanced smart cards that may contain batteries, LEDs, LCDs, polymer dome switches, fingerprint sensors, and other electronic components that are not found in conventional smart cards. A conventional smart card is the size of a traditional credit card, and they usually contain an Integrated Circuit (IC) chip and may contain an antenna if the card must transfer data using Radio Frequency (RF) transmission. Advanced smart cards may include components that are not found in conventional smart cards, such as batteries, displays, and keypads. Advanced smart cards may therefore be capable of many sophisticated functions, such as displaying data, enabling users to enter Personal Identification Numbers (PIN) and passwords, and detecting security threats. 
     Smart cards are being widely utilized for access control systems, storage of biometric data, national border control, and in many other applications. Smart cards typically contain information about a user. For example, the U.S. Department of Defense (DoD) Common Access Card (CAC) project requires a contactless chip to contain biometric data about a citizen including a digitized portrait and fingerprint data. 
     These advanced smart cards typically consist of a multi-layer structure having one or more plastic layers surrounding integrated circuits that store the data. Data is transferred to and from the cards through radio frequency (RF) transmission. Cards that transfer data only by RF transmission are so-called “contactless” cards. For RF transmission, contactless advanced smart cards include an antenna for transmitting data to and from the integrated circuits. With increasing security concerns in the post-September 11 environment, contactless RFID chips are being incorporated into documents like passports and other document or note formats. 
     Several problems exist with prior art smart card arrangements in that PVC is utilized for its rigidity in order to protect the antenna and integrated circuit from breaking upon flexure. Each layer of PVC must be of a prescribed thickness to surround and protect the components. In order to maintain the rigidity required and house the components necessary, these PVC cards tend to be relatively thick as compared to other types of cards such as a credit card. Generally, such resulting multi-layer structures are approximately 0.060 inches thick. Additionally, PVC tends to become brittle with age and exposure to ultraviolet rays. This contributes to card failure in time. Additionally, specialized printing equipment is required to print information on the outer surfaces of the PVC material. 
     Many other problems frequently occur with the very high temperatures and pressures required for hot lamination including damage to fragile Integrated Circuit (IC) chips, antenna (often thin wire coils, thinly etched copper, or thinly deposited silver), and other electronic components. The very high heat levels, typically about 300° F., and the very high pressures, typically ranging from 1,000 to 30,000 PSI or greater, used in the plastic card lamination production process are the cause of severe thermal and physical stress on smart card components. 
     What is needed is an improved method for producing an Advanced Smart Card (containing Integrated Circuits, antennae, batteries, polymer dome switches, Liquid Crystal Displays, Light Emitting Diode arrays, fingerprint sensors), that allows sensitive components to be securely and reliably incorporated into a very thin and flexible card structure, and that utilizes low heat (e.g. less than 150° F.) and low pressure (e.g. less than 100 PSI). 
     A new generation of highly sophisticated smart cards has become technically feasible due to advances in materials science and electronics. Miniature batteries, data displays, keypads, and even fingerprint sensors have been developed that may be incorporated into a smart card sized form factor. These advances are stimulating new smart card capabilities and applications. For example, a smart card equipped with a battery, data display, and keypad would enable users to view data regarding: 1) the current balance of electronic purse applications, 2) recent credit card transaction information, or 3) bank account balance information. These capabilities could also be utilized to enhance security with password-enabled credit card functions. While these expanded smart card capabilities offer tremendous potential for new applications, large scale production of advanced cards with lamination-based manufacturing techniques is extremely difficult due to the electronic component damage caused by the high heat and pressure used in lamination. A new card production process utilizing low heat and pressure is needed to enable delicate electronic components to be effectively incorporated within card bodies. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of this invention to provide an Advanced Smart Card with a thickness not greater than 0.80 mm (the thickness of a conventional credit card) that contains securely encapsulated Advanced Smart Card electronics that may include: Integrated Circuits, antennae, batteries, polymer dome switches, Liquid Crystal Displays, Light Emitting Diode arrays, fingerprint sensors. 
     This and other objects are achieved by providing a multi-layer card structure with a top layer of material such as synthetic paper, PVC, PC, or other suitable material, a bottom layer that is comprised of an integrated electronics assembly (that may include Integrated Circuits, antennae, batteries, polymer dome switches, Liquid Crystal Displays, Light Emitting Diode arrays, and fingerprint sensors), with a core layer of injected polymeric material that securely encapsulates the electronic components that make up the bottom layer, and securely bonds to the top layer of synthetic paper or other suitable material. 
     The void space between the top layer and the bottom layer facilitates an even flow and a complete encapsulation of the electronic components by injected polymeric material. The void space of approximately 0.1 to 0.25 mm allows injected polymer to fill the void space and cover the electronic components and the bottom surface of the top layer, with no voids, pockets and with an even and complete distribution of the polymeric material in the void space. 
     The integrated electronics assembly that makes up the bottom layer is produced on a single continuous sheet, which is then cut by a machine tool in a form that allows the Advanced Smart Card perimeter to be covered by the injected polymer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cut-away side view of an Advanced Smart Card made according to the teachings of this patent disclosure. 
         FIGS. 2 and 3  are cut-away side views of a mold tool set up for making a first preferred embodiment of an Advanced Smart Card of this patent disclosure wherein certain Advanced Smart Card components (e.g. Integrated Circuit chips and antenna coil) are shown before a liquid polymeric material is injected between the Advanced Smart Card&#39;s top and bottom layers (see  FIG. 4  and after (see  FIG. 5 ) the polymeric material is injected into a void space between the top and bottom layers and thereby filling said void space with a polymeric material and cold forming the top layer of the Advanced Smart Card to the contour of the top mold&#39;s document-forming cavity. 
         FIG. 4  is a cut-away view showing a mold tool being removed from a precursor Advanced Smart Card body formed by the system generally depicted in  FIG. 3 . 
         FIG. 5  depicts a mold tool system that is capable of making six Advanced Smart Cards (with dimensions of approximately 54 mm by 85 mm) simultaneously. 
         FIG. 6  illustrates a cut-away view of a Contacted Advanced Smart Card made according to the teachings of this patent disclosure. 
         FIG. 7  illustrates a cut-away view of a Contactless Advanced Smart Card made according to the teachings of this patent disclosure. 
         FIG. 8  illustrates a cut-away view of a Dual Interface Advanced Smart Card made according to the teachings of this patent disclosure. 
         FIG. 9  illustrates a cut-away view of a Dual Interface Advanced Smart Card with a Fingerprint Sensor  30  made according to the teachings of this patent disclosure. 
         FIG. 10  illustrates a cut-away view of a Chemosensitive Advanced Smart Card with a Sensor Strip  37  that is chemically reactive and provides a visual signal when particular chemical substances or radiation has been detected. The heat-sensitive Sensory Strip is protected from high temperature deterioration by the low-temperature, low-pressure process used with the card manufacturing method in this disclosure. 
         FIG. 11  illustrates a cut-away view of a Contactless Advanced Smart Card with an Acoustic Speaker  73  made according to the teachings of this patent disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  depicts a cut-away side view of an Advanced Smart Card  22  made according to the teachings of this patent disclosure. In its finished form, such an Advanced Smart Card will be comprised of a top layer  24 , a bottom layer  26 , and a center or core layer  28 . 
     The top layer  24  is a film or sheet of synthetic paper PVC, Polycarbonate, or other suitable material. The bottom layer  26  is an electronics assembly on substrate circuit board (e.g. polyimide for flexible printed circuits or industry standard FR 4  for conventional printed circuit boards) containing a number of integrated electronic components such as a Light Emitting Diode (LED)  30 , a battery  32 , a polymer dome switch  33 , a microprocessor  35 , an antenna  31 , a Liquid Crystal Display (not shown). The center or core layer consists of a thermosetting polymeric material  34  (e.g., an initially liquid or semi-liquid thermosetting resin) that, upon curing, constitutes the center or core layer  28  of a finished Advanced Smart Card. The center or core layer  28  completely encapsulates all exposed electronic components on the top surface of the bottom layer  26 . The thermosetting material  34  that eventually becomes the center layer  28  of the Advanced Smart Card is injected into the void space  36  between the top layer  24  and bottom layer  26 . This injected polymeric material  34  should be capable of being injected under the relatively cold, low pressure forming conditions employed in applicant&#39;s process. 
     In any case, such thermosetting polymeric materials will be injected into, and fill, the void space  36  defined between the inside surface  38  of the top layer  24  and the inside surface  40  of the bottom layer  26 . Upon curing, the polymeric material  34  of the center layer  28  should bond or otherwise adhere to both the inside surface  38  of the top layer  24  and the inside surface  40  of the bottom layer  26  to produce a unified Advanced Smart Card body. Such adhesion can be aided by treating the inside surfaces  38  and  40  of the top and bottom layers, respectively, in any one of several ways. 
     For example, bond promoting agents known to this art (e.g. chloro-polyolefins) may be employed to enhance bonding between the core layer-forming thermoset material and the material(s) from which the top and bottom layers are made (e.g., PVC, polyimide). By way of example only, Minnesota Mining and Manufacturing&#39;s base primer product 4475.RTM can be used for this bond enhancing purpose, especially when the top or bottom layer material is PVC. Other treatments that can be applied to the inside surfaces of the top and/or bottom layers include plasma corona treatments and acid etching. 
     The Advanced Smart Card&#39;s thickness  39  is defined by placement of the mold faces (not shown in  FIG. 1 ) as the thermoset material is injected into the void space  36  as part of the cold, low pressure forming process of this patent disclosure. In effect, the injection of the thermoset material into the void space  36  between the top and bottom layers fills any portion of that void space  36  that is not otherwise occupied by the electronic components protruding from the bottom layer  26 . 
     The layout of electronic components on the top surface of the bottom layer in the manner generally suggested in  FIG. 2  allows the incoming liquid or semi-liquid polymeric material to flow over and around all sides of exposed electronic components. 
     The elastomeric properties of the cured thermoset polymer provide protection from physical and thermal stressors for the electronic components in the bottom layer. The shock-absorbing properties of the elastomer that encapsulates all exposed electronics enable the assembly to resist flexion and/or torsion and/or impact forces that the Advanced Smart Card may encounter upon either of its major outside surfaces or on any of its four outside edge surfaces. The thermal insulation properties of the elastomer also reduce the amount of heat to which the electronic components may be exposed during a final hot lamination process employing a thin layer of PVC to create a high quality exterior surface on the bottom surface of the bottom layer. 
       FIGS. 2 and 3  are contrasted to illustrate a first preferred embodiment of applicant&#39;s methods for making Advanced Smart Cards. 
     That is to say that  FIG. 2  depicts a particularly preferred embodiment of this invention wherein a flat, top layer or sheet  24  of synthetic paper or plastic material such as PVC is shown before it is cold, low pressure formed according to the teaching of this patent disclosure. In other words,  FIG. 2  depicts the mold tool set-up just prior to the injection of the polymeric material and wherein a flat, top layer  24  (e.g., a flat sheet of PVC) is shown as it is initially placed under an Advanced Smart Card-forming cavity of the top mold  44  and a bottom layer  26  (e.g., an integrated electronics assembly on a substrate) is shown as it is placed over a bottom mold  46 . Again, however, in some less-preferred, but still viable, embodiments of applicant&#39;s processes the top layer  24  may be pre-molded or at least partially pre-molded, preferably, to the general contour of the Advanced Smart Card-forming cavity  64  in the top mold. By way of comparison, the bottom mold  46  has no cavity comparable to the cavity in the top mold  44 . A nozzle  48  for injecting a liquid or semi-liquid, thermoplastic or thermosetting polymeric material  34  is shown being inserted into an orifice  49  that leads to the void space  36  that is defined between the inside surface  38  of the top layer  24  and the inside surface  40  of the bottom layer  26 . The distance between the top surface of the top layer and the bottom surface of the bottom layer of the Advanced Smart Card is depicted by distance  39 . The void space  36  is shown extending from the left end to the right end of the juxtaposed top layer  24  and bottom layer  26 . In other words, in  FIG. 2  the outside surface  55  of the top layer  24  is not yet in contact with the inside surface  56  of the Advanced Smart Card-forming cavity  64  of the top mold  44 . By way of contrast, the outside surface  58  of the bottom layer  26  is shown in substantially flat, abutting contact with the inside surface  60  of the bottom mold  46 .  FIG. 3  depicts the effects of injecting the thermoset polymeric material into the void space  36  between the top and bottom layers  24  and  26 . Thus,  FIG. 3  shows the top layer  24  after it has been molded into an Advanced Smart Card-forming cavity  64  in the top mold  44 . 
     In both  FIGS. 2 and 3  the electronic components contained in the bottom layer  26  of the Advanced Smart Card (e.g., the antenna  31 , battery  32 , IC chip  35 ) are shown as they may be positioned in the integrated electronics assembly comprising the bottom layer. This invention for producing Advanced Smart Cards is compatible and viable for a wide range of card designs that incorporate a variety of components and devices in the bottom layer. The detailed design of the electronic components in bottom layer  26  will depend on the specific application(s) for which the Advanced Smart Card is intended. These applications may include: access control for building entry, data display for bank cards or ATM cards, password entry for Identification Cards, and fingerprint verification (using a fingerprint sensor) for security-related applications. 
     For the purpose of this invention, the detailed design of the circuit and electronic components in bottom layer  26  is not critical except for the dimensional constraints that must be satisfied. For an ISO 7810-compliant Advanced Smart Card produced using this method, the electronic elements in the bottom layer must fit within a form factor of 81 mm (length) by 49 mm (width) and with a maximum height of 0.55 mm (including the bottom layer substrate). The distance  43  in  FIG. 3  is about 0.15 mm and it represents the minimum clearance from the inside surface  38  of the top layer  24  and the top-most surface of the highest electronic component  30  mounted on the bottom layer  26 . The minimum distance  43  is required to allow sufficient injected polymeric material to encapsulate the electronic components mounted on the bottom layer and to provide adequate shock-absorption and thermal insulation properties. 
     In  FIG. 2  the top mold  44  is shown having a cavity  64 , which defines the surface contour of the top of the Advanced Smart Card to be formed during the injection process. To this end, the injection of the liquid or semi-liquid thermoset polymeric material  34  should be under pressure and temperature conditions such that the top layer  24  is cold, low pressure, formed into the cavity  64  of the top mold  44 .  FIG. 3  shows how the cold, low pressure forming process of this patent disclosure has in fact conformed the top surface  55  of the top layer  24  to the configuration of the Advanced Smart Card-forming cavity  64  in the top mold  44 . Again, the bottom surface  58  of the bottom layer  26  is shown in  FIG. 3  molded against a substantially flat inside surface  60  of the bottom mold  46 . This is a particularly preferred arrangement for making the Advanced Smart Cards of this patent disclosure. 
     In  FIGS. 2 and 3  a front lip region  66  of the top mold  44  and a front lip region  68  of the bottom mold  46  are shown spaced apart from each other by a distance  70  that (taking into consideration the thickness of the top and bottom layers  24  and  26 ), in effect, defines the distance  36  (i.e., the width of the void space) between the top layer  24  and the bottom layer  26  at these lip regions of the two molds  44  and  46 . This distance  70  should be such that the thermoset polymeric material  34  can be injected into the void space  36  over the entire length of the Advanced Smart Card (e.g., from its left side to its right side). The counterpart distance  70 ′ of the mold device setting on the right side of the system shown in  FIG. 2  may differ from that of its counterpart distance  70  on the left side. In any case the distance  70 ′ should be such that the distance  36 ′ defined between the inside surface  38  of the top layer  24  that passes through the rear lip  66 ′ of the top mold  44  and the inside surface  40  of the bottom layer  26  that passes through the rear lip  68 ′ of the bottom mold  46  is very small—but still finite. That is to say that this very small distance  36 ′ should be large enough to allow gases  72  (e.g., air, polymeric ingredient reaction product gases, etc.) in the void space  36  that originally existed between the top and bottom layers  24  and  26  (see again,  FIG. 2 ) and excess polymeric material to be exhausted from said void space  36 , but still be small enough to hold the injection pressures used to inject the thermoset polymeric material. Indeed, the distance  36 ′ is preferably sized large enough to allow even thin layers of the liquid polymeric material  34  itself to be “squirted” or “flashed” out of the void space  36 —and thus allowing all gases residing in, or created in, the void space  36  to be expunged out of said void space and, indeed, out of the mold system itself. Thus, all such gases  72  are completely replaced by the incoming liquid thermoset material  34 . This gas exhaust technique serves to prevent gas bubbles from forming in the body of the thermoset material  34  that eventually (i.e., upon curing of the thermoset material) comprises the center layer  28 . 
       FIG. 4  shows a semi-finished or precursor Advanced Smart Card of the type shown in  FIG. 3  being removed from a mold system. Section lines  84 - 84  and  86 - 86  respectively show how the left end and right end of the precursor Advanced Smart Card can be cut or trimmed away to create the sharp edges and precise dimensions of a finished Advanced Smart Card. In this case the distance  74  is about 85 millimeters to conform to ISO 7810 specifications for an Identification Card. 
       FIG. 5  illustrates a molding procedure being carried out according to some of the preferred embodiments of this patent disclosure wherein six Advanced Smart Cards with dimensions of approximately 85 mm by 54 mm are being molded simultaneously. 
       FIG. 6  illustrates a completed contacted Advanced Smart Card made according to the teachings of this patent disclosure. 
       FIG. 7  illustrates a completed contactless Advanced Smart Card made according to the teachings of this patent disclosure. 
       FIG. 8  illustrates a dual interface Advanced Smart Card made according to the teachings of this patent disclosure. 
       FIG. 9  illustrates a dual interface Advanced Smart Card with fingerprint sensor  30  made according to the teachings of this patent disclosure. 
       FIG. 10  illustrates a chemosensitive Advanced Smart Card with a sensor strip  37  that is chemically reactive and provides a visual signal when particular chemical substances or radiation has been detected. The heat-sensitive sensor strip is protected from high-temperature deterioration by the low-temperature, low-pressure process used with the card manufacturing method in this disclosure. 
       FIG. 11  illustrates a contactless Advanced Smart Card with an acoustic speaker  73  made according to the teachings of this patent disclosure. 
     While this invention has been described with respect to various specific examples and a spirit that is committed to the concept of the use of special glues and gluing procedures, it is to be understood that the hereindescribed invention should be limited in scope only by the following claims.