RF proximity financial transaction card having metallic foil layer(s)

[0001] 1. Field of the Invention

[0002] The present invention relates to contactless financial transaction cards embodying RF proximity components that facilitate wireless data communication with reading devices. More particularly, the invention concerns RF proximity financial transaction cards having one or more metallic foil layers designed to provide a decorative reflective surface.

[0003] 2. Description of the Prior Art

[0004] By way of background, one type of contactless financial transaction card, commonly known as an RF proximity card, contains RF proximity components that allow such cards to be polled by wireless reader devices when the cards are brought into proximity therewith. However, RF proximity cards are generally functionally incompatible with the metallic foil layers that are sometimes used in financial transaction cards to provide decorative reflective surfaces. The foil layers tend to attenuate the RF signals exchanged between card and reader to the point where wireless communication is not possible at any distance from the reader. The present invention provides metallized foil financial transaction cards that can be used for RF proximity applications.

[0005] An RF proximity financial transaction card includes a plastic inlay having first and second substantially planar surfaces bounded by a continuous peripheral edge. An integrated circuit carried by the inlay stores card-specific data. An antenna carried by the inlay is operatively connected to the integrated circuit. A metallic foil layer substantially overlies at least one of the substantially planar surfaces. The foil layer provides the financial transaction card with a decorative metallic reflective appearance. Printed graphics or text may be disposed on or above the metallic foil layer. The card is constructed to inductively couple with a card reader that is spaced from the card in order to support limited-range wireless communication between the card and the card reader up to a maximum coupling distance, beyond which it will not couple.

[0019] Turning now to the figures, wherein like reference numerals are used to represent like elements in all of the several views, FIGS. 1-3 illustrate an RF proximity financial transaction card 2 constructed in accordance with an example embodiment. As used herein, a financial transaction card refers to a card having the purpose of conducting financial transactions such as a credit card, gift card, debit card, or stored value card, associated with payment. Financial transaction card physical characteristics, performance, and use may be governed by one or more of the following standards and test methods: ISO/IEC7810, ISO/IEC7811, ISO/IEC7813, and ISO/IEC 10373. A financial transaction card is typically configured as a rigid planar sheet of desired shape, typically made of plastic, having dimensions less than 5 inches×5 inches and a thickness between 0.005″ and 0.100.″ The most typical form is rectangular and is suitable for carrying in a purse or wallet. Such cards typically measure about 2.125″×3.3 75″×0.030,″ and have rounded corners.

[0020] A contactless integrated circuit (CICC) card refers to a card that contains within it an integrated circuit with data storage capability and an antenna for communicating via RF induction technology. Depending on application requirements, the integrated circuit may or may not include a microprocessor in addition to the circuit's data storage capability. Contactless cards are passive and the integrated circuit is only powered up when presented nearby to a card reading device (card reader). A card reader is a powered device for transmitting and receiving data to and from the contactless card via induction. As shown in FIG. 4, the card reader emits an electromagnetic RF field that powers the integrated circuit electronics within the card. The card antenna resonates when power is induced therein by the card reader magnetic field emissions. Digital information may then be transferred back and forth between the card and the card reader. In order for this to occur, the overall card design (including antenna, components, materials, and their arrangement) needs to be such that the card will optimally couple with the card reader.

[0021] Contactless cards may be classified according to their operating range. Three existing categories of contactless card are RF close-coupled cards for very close operation, RF proximity cards for nearby operation, and RF vicinity cards for longer distance operation. Each of these categories is governed by specifications jointly promulgated by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). The current governing specification for RF close-coupled cards is ISO/IEC 10536. This standard calls for a near surface-to-surface contact coupling range with RF close-coupled card readers that operate at a frequency of 125 kHz or 134 kHz. The current standard governing RF vicinity cards is ISO/IEC 15693. This standard calls for a coupling range of 0-1.5 meters with RF vicinity card readers that operate at a frequency of 900 MHz.

[0022] Although the card 2 may be constructed according to the above specifications governing RF close-coupled cards and RF vicinity cards, contactless financial transaction cards are most commonly constructed as RF proximity cards. The current governing specification for RF proximity cards is ISO/IEC 14443. According to this standard, the maximum coupling distance of RF proximity cards is within a range of 0-10 cm. This specification also provides that the card readers operate in the vicinity of 13.56 MHz+/−7 kHz at an RF Field Strength of 1.5-7.5 A/m rms. It should also be noted that some financial transaction card applications are set up with a maximum coupling distance within the range of 0-4 cm or a maximum coupling distance within the range of 4-10 cm, which are more stringent specifications and within the 0-10 cm range set for RF Proximity Cards.

[0023] The stated ranges for maximum coupling distance are related to practical functionality and desirable security for RF proximity card reading applications. If the card couples with the reader at a maximum distance of 4 cm or 10 cm, it couples at lesser distances from the reader as well. What is of interest is the maximum coupling distance of the card with respect to the reader. Being able to couple at distances greater than 4 cm or 10 cm may represent a security risk and may not be desirable for financial transaction card applications. For example, contactless cards in the pockets of users could potentially be scanned in an unauthorized manner if the cards were designed to couple at very large distances. On the other hand, it may also not be desirable to have a card that needs to directly contact the reader in order to couple (i.e., a coupling distance of zero). Such a card would be more difficult to use, and the use may be less reliable. It will be appreciated that the above-described specifications for RF proximity cards may be modified in the future (for example, in regard to maximum coupling distance specified for proximity applications, reader frequency and power output). The RF proximity cards disclosed herein are therefore intended to encompass all such modifications.

[0024] As shown in FIGS. 1-3, the card 2 includes an RF inlay 4 comprising a substrate 4a made of a suitable plastic material. Representative plastics that may be used include, but are not necessarily limited to, materials selected from the group consisting of polyvinyl chloride (PVC), polyethylene terephthalate glycolized (PETG), unmodified amorphous polyethylene terephthalate (APET), acrylonitrile-butadiene-styrene (ABS), general purpose polystyrene (GPPS), high impact polystyrene (HIPS), polyethylene terphthalate (PET), and combinations of the foregoing materials. The inlay 4 has first and second substantially planar surfaces 4b and 4c bounded by a continuous peripheral edge 4d. The substrate 4a carries an integrated circuit 4e for storing card-specific data and an antenna 4f operatively connected to the integrated circuit. As is conventional, these components may be bonded to or embedded within the substrate 4a. The construction details of the integrated circuit device and the antenna are well known in the art, and will not be described further herein. Such devices are readily available from commercial sources, and are generally sold as complete inlays (e.g., the inlay 4) ready for lamination into a contactless card. Assuming it is constructed in accordance with the RF proximity card ISO/IEC 14443 specification, the card 2 incorporating the integrated circuit 4e and the antenna 4f would be referred to as a PICC (Proximity Integrated Circuit Card). If the card 2 is implemented as an RF close-coupled card in accordance with the ISO/IEC 10536 specification, it would be referred to as a Close-Coupled CICC. If the card 2 is implemented as an RF vicinity card in accordance with the ISO/IEC 15963 specification, it would be referred to as a VICC (Vicinity Integrated Circuit Card).

[0025] The integrated circuit 4e stores financial information (e.g., identification data, credit data, debit data, etc.) in machine readable (e.g., digital) form. The financial transaction information could comprise an account number and/or account security information that is stored by the device, or it could comprise a code that corresponds to financial transaction information stored externally of the card (e.g., a barcode that when read allows financial transaction information associated with the card to be retrieved from a database). The antenna 4f is designed to inductively couple with an RF proximity card reader, which is spaced from the card 2 within the maximum coupling range specified by the applicable ISO/IEC standard in order to support wireless communication between the integrated circuit device 4e and the card reader. As indicated above, an RF proximity card couples with a nearby RF proximity card reader when the card antenna resonates. Power is induced in the card antenna by the magnetic field emitted from the card reader. Digital information may then be transferred back and forth between the card reader and the card. For this to happen, the card antenna and the card reader antenna need to be appropriately tuned within the environment of the card construction, reader construction, and environmental surroundings.

[0026] Designing an RF proximity card antenna involves choosing wire type, gauge, antenna shape, number of windings, circuit resistance, etc., so that the antenna transmits, receives, or resonates at the intended frequency and power. In the card 2, the antenna 4f is conventional in nature, and may be designed so that the card will inductively couple with an RF proximity card reader used for RF proximity cards according the applicable ISO/IEC 14443 specification. As shown in FIG. 1, the antenna 4f may be constructed with one or more four-sided antenna windings arranged in close proximity to each other and with the peripheral edge 4d. Other antenna designs may also be used. For example, instead of the antenna 4f extending around the entire peripheral edge 4d, it might cover only half the card 2, such that the antenna windings are proximate only to two or three sides of the peripheral edge 4d. As stated, for RF proximity cards, the maximum coupling distance for the card from an ISO/IEC 14443 compliant reader (frequency approximately 13-15.5 MHz at a field strength of approximately 1.5-7.5 A/m rms) is typically in the range of 0-10 cm or, depending on the application, specified to be more stringent, such as in the ranges of 0-4 cm or 4-10 cm.

[0027] The card 2 further includes a metallic foil layer 6 that substantially overlies at least one of the surfaces 4b or 4c. FIGS. 1-3 illustrate a two-foil layer construction wherein there are two metallic foil layers 6 that respectively cover the surfaces 4b and 4c. As additionally shown in FIG. 5, a single foil layer construction comprising only one metallic foil layer 6 may also be used. In that case, a substitute sheet 8 of desired thickness could replace the lower (or upper) metallic foil layer 6 of FIG. 1. The substitute sheet 8 may be formed using any of the plastic materials identified above in describing the inlay 4. It may be used if additional layer thickness is required in order to comply with financial transaction card size requirements. Otherwise, the substitute sheet 8 may not be required. The substitute sheet 8 may be opaque, clear (e.g. transparent or translucent), or partially light transmissive (within the human visible light range).

[0028] As shown in FIGS. 2 and 3, printed graphics or text 10 are printed on one or both of the metallic foil layers 6 (or on the substitute sheet 8, if present). Such information could also be printed above the metallic foil layers 6 or the substitute sheet (if present), such as on an overlay sheet. In most cases, one or both of the metallic foil layers 6 (or the substitute sheet 8, if present) will have printed information and/or graphics on or above surfaces thereof. For example, these layers may be printed with a card provider name and emblems. Other graphical items may also be applied to such layers, such as decorative designs and images. The substitute sheet 8 (if present) for carrying such printing and/or decorative coatings, may be a plastic material such as vinyl with a mounted thin layer of PET (Polyethylene Terephthalate), the PET having the function of balancing the metallic foil layer opposite it in the card construction.

[0029] Completing the card 2 are a pair of conventional transparent overlay sheets 12 and 14 that can be made from any of the plastic materials identified above in describing the inlay 4. The overlay sheets 14 and 16 are used to cover and protect the printed information during card use. It is also possible to substitute for the overlay sheets using conventional press-polish coatings to also provide protection for the printed information on the card. A magnetic storage device 16 (e.g., a “mag stripe”) may be optionally provided on the lower overlay 14 to store card-specific data in case an RF card reader is not available. The lower overlay 14 may also optionally carry a conventional signature panel 18. If present, the magnetic stripe 16 and the signature panel 18 may be provided on the exposed outer surface of the overlay 14. The magnetic stripe 16 may be used to store financial information (e.g., identification data, credit data, debit data, etc.) in machine readable (e.g., digital) form that can be read using a conventional card swiper. Other machine readable financial information storage or reference devices, such as barcodes, could also be present on the card 2.

[0030] The metallic foil layers 6 provide the card 2 with a decorative metallic reflective appearance. Different types of metals may be used, depending on the desired visual effect to be achieved. Examples include, but are not limited to, aluminum, copper, nickel, gold, silver, chromium, tin and lead. The metallic foil layer(s) 6 may also have any desired surface appearance or finish, including but not limited to, mirror reflective, gloss, semi-gloss, matte, rainbow, tinted, anodized, brushed, embossed, chemically etched, laser etched, holographically imaged, holographically etched, other surface treatments, and combinations thereof. The metallic foil layer(s) 6 may also have any desired color, including but not limited to aluminum, silver, gold, copper, chrome, bronze, gun-metal, charcoal, black, grey, blue, red, green and combinations thereof.

[0031] The metallic foil layer(s) 6 will thus provide a desired aesthetic characteristic of the card 2, contributing to the attractiveness of the card's graphic design and preferably conveying a favorable card issuer corporate image and providing the cardholder with a desirable personal self-image and perceived socioeconomic status. This is to be differentiated from using foil in cards for functional purposes, such as security stamps, or in antenna design. As stated, each metallic foil layer 6 substantially overlies one of the substantially planar surfaces 4b or 4c, although portions the foils layers may be selectively removed in some embodiments to support RF operation, as described in more detail below. In addition, there may be aesthetic reasons why the metallic foil layers do not completely cover the substantially planar surfaces 4b or 4c. Generally speaking, however, the goal of the metallic foil layers 6 is to provide a metallic reflective appearance across the front and/or rear face of the card 2.

[0032] Turning now to FIG. 6, each metallic foil layer 6 may be formed as a thin metallic foil sheet material 6a bonded to a backing layer 6b. The backing layer 6b may be formed using any of the plastic materials identified above in describing the inlay 4. Such materials may be opaque or transparent. The metallic foil sheet material 6a will usually be quite thin, e.g., between about 0.05-1.5 mils. Thus, the backing layer 6b is used to facilitate material handling during card lamination. The thickness of the backing layer 6b may vary, with 6-9 mils being suitable for supporting the foil sheet material 6a.

[0033] There are at least two types of foil that may be used for the foil sheet material 6a. One is a continuous metal foil that is a self-supporting sheet of metal. Such sheets typically range in thickness from 0.5-10 mils, with 0.5-1.5 mils being most compatible with the thickness constraints on financial transaction cards (i.e., 27-33 mils). This type of metallic foil sheet material 6a can be mounted to the backing layer 6b using a suitable adhesive. Another type of foil sheet material 6a is a metallized film comprising a thin plastic sheet or film of thickness 0.15-15 mils, such as polyester, nylon, or polypropylene, which has been sputtered or vacuum metallized with one or more thin layers of continuous metal (typically aluminum or chromium) to give a reflective metallic appearance. For the card 2, a plastic film thickness of 1 mil was found to be adequate. Sputtering can lay down a continuous metal coating of 5000 Angstroms or less. Vacuum metallizing can lay down a metal coating of 1000 Angstroms or less. Vacuum metallizing and sputtering, as generally practiced, provide a continuous layer of metal mounted on the plastic. This differs from a coating of metal particles in a coating vehicle or a printed pattern of metal in an ink vehicle where the metal particles are not necessarily in contact with each other. This type of metallic foil sheet material 6a can be mounted to the backing layer 6b using a conventional heat lamination technique and adhesives.

[0034] The card 2 may be formed using a conventional lamination technique with conventional financial transaction card production lamination equipment. Currently, financial transaction cards are typically made of a multitude of plastic layers in large sheet form (e.g., from 12″×18″ to 48″×48,″ with 22.75″×27.75″ being typical). The large form sheets are laminated together in a platen press operation under heat and pressure. Multiple large form card sheets are often laminated in the platen press concurrently by interspersing pre-laminate lay-ups among sets of eleven polished rigid steel plates, with ten pre-laminate lay-ups to a lamination book, and several lamination books to a press loading (other book and press combinations are possible). A typical lamination cycle is 10-30 minutes of applied heat (e.g., 17 minutes) at a temperature of 200E-350F (e.g., 300F), followed by 10-30 minutes of cooling (e.g., 17 minutes), all under effective pressures ranging from 100 to 600 psi. After lamination, the sheets are cut into cards having a substantially rectangular shape with rounded corners and respective height and width dimensions of 2.125″×3.375″ (there are also several less popular sizes). Signature panels, hologram stamps, and embossments are then added to each card.

[0035] Assuming the card 2 is to have an industry standard thickness range of approximately 30 mils (e.g., 27-33 mils), a suitable thickness range for the inlay 4 will be approximately 10-18 mils. Similarly, a suitable thickness range for the metallic foil layer(s) 6 will be approximately 7.5-10.5 mils (including the thin foil material sheet 6a and the backing layer 6b). If only one metallic foil layer 6 is present and the substitute sheet 8 is used, its thickness may be that of a standard financial transaction card core sheet, namely approximately 6-12 mils. If a PET layer is on the substitute sheet 8, its thickness range may be approximately 0.5-1.5 mils. The overlay sheets 12 and 14 may each have an industry standard thickness range of approximately 1-2 mils.

[0036] Shown below are two tables respectively illustrating example laminate layer thicknesses for the card 2 when constructed with two metallic foil layers 6 and with one such layer, respectively:

[0037]

TABLE 1
Two Metallic Foil Layers
	Layer 1	Clear Plastic Overlay (14): 1-2 mils
	Layer 2a	Foil Sheet Material (6a): 0.05-1.5 mils
		(With printing and/or decorative coatings)
	Layer 2b	Opaque or Clear Backing Layer (6b): 6-9 mils
	Layer 3	RF Inlay (4): 10-16 mils
	Layer 4a	Opaque or Clear Backing Layer (6b): 6-9 mils
	Layer 4b	Foil Sheet Material (6a): 0.05-1.5 mils
		(With printing and/or decorative coatings)
	Layer 5	Clear Plastic Overlay (16): 1-2 mils

[0038]

TABLE 2
One Metallic Foil Layer
	Layer 1	Clear Plastic Overlay (14): 1-2 mils
	Layer 2a	Foil Sheet Material (6a): 0.05-1.5 mils
		(With printing and/or decorative coatings)
	Layer 2b	Opaque or Clear Backing Layer (6b): 6-9 mils
	Layer 3	RF Inlay (4): 10-16 mils
	Layer 4a	Opaque or Clear Core Sheet (8): 6-12 mils
	Layer 4b	PET Layer on Core Sheet: 0.5-1.5 mils
		(With printing and/or decorative coatings)
	Layer 5	Clear Plastic Overlay (16): 1-2 mils

[0039] As stated in the Background section of this document, RF proximity financial transaction cards are generally functionally incompatible with metallic foil layers due to attenuation of the RF signals exchanged between the card and reader. Applicants believe that the mechanism of interference may be the formation of eddy currents induced in the foil by the RF signal. Applicants have discovered that the signal attenuating effect of metallic foil in an RF proximity financial transaction card can be mitigated by constructing the card 2 using certain design principles. By applying these design principles, one or more metallic foil layer(s) in an RF proximity financial transaction card may be used while still permitting the card to inductively couple with the card reader up to a desired maximum coupling distance. It has been further determined that the card construction can be varied depending on whether the foil comprises actual metal foil or a metallized film, as discussed above. For actual metal foil having a relatively high metal content, one design approach that may be used is to pattern the foil in the vicinity of the card antenna using one or more strategic cutouts. For metallized film, another design approach that may be used is to limit the metal content while maintaining a sufficient metal opacity to provide a metallic decorative effect. It is estimated that the metal thickness needed to provide a decorative effect is approximately 5 Angstroms for the metals listed above. For aluminum, which has a density of 2.7 g/cc., this thickness corresponds to a metal weight/area (metal content) of 0.000000868 g/sq. in. If the metal content of the metallized film cannot be sufficiently reduced without sacrificing decorative effect, then the patterning technique proposed for metal foil may be used.

[0040] Several examples will now be described to better illustrate the design principles summarized above. In each of the examples, RF proximity financial transaction cards (test cards) per ISO/IEC 14443 were constructed in the manner described thus far, while varying the metallic foil layers. In order to evaluate the test cards, a Saturn 3000 Reader manufactured by OnTrack Innovations (OTI) was procured. This reader is ISO/IEC14443 compliant. As described above, this is the prevailing standard for RF proximity cards. The reader has a flat 4.50″×2.75″ antenna sensor. When an ISO/IEC 14443 compliant card is placed parallel to the sensor, in a range somewhere between 0-10.0 cm, the reader emits an audible beep signifying a successful coupling of the reader with the card. The test cards were evaluated by measuring the maximum distance away from the sensor surface a card can be placed and yet still return the audible beep signifying coupling with the reader. The test cards were mounted on a horizontal plane, and the antenna sensor of the reader was raised and lowered via a lab jack to precisely adjust and measure the distance between the card and reader.

I. Examples Based On Metal Foil Cards

[0041] the following examples are all based on cards whose metallic foil layers use actual metal foil, namely aluminum foil having a thickness ranging between 0.22-1.50 mils obtained from Republic Foil Inc. The RF inlay was obtained from Inside Contactless Corporation, product designation Micropass L4-2G. The card 20 shown in FIG. 7 illustrates the shape of the antenna for this RF inlay (shown by reference number 24). The plastic layers were constructed using PVC overlay film and corestock materials obtained from Klockner Pentaplast GmbH.

[0042] In this example, four cards with different thicknesses of aluminum foil completely covering one card face were produced and tested. The design model for each card was as follows:

[0043]

	Layer 1	Klockner Pentaplast SB6 vinyl overlay film with
		adhesive facing aluminum foil: 1.5 mils
	Layer 2	Republic Foil aluminum foil: 0.22-1.50 mils
	Layer 3	Klockner Pentaplast SB6 vinyl film with
		adhesive facing aluminum foil: 1.5 mils
		(With printing and/or decorative coatings)
	Layer 4	Micropass L4-2G RF inlay: 15 mils
	Layer 5	Klockner Pentaplast clear vinyl corestock: 8 mils

[0044] The four cards evaluated in this example had respective foil thicknesses of 0.22, 0.35, 0.60 and 1.50 mils. Based on the density of aluminum, the foregoing foil thicknesses correspond to a metal weight/area of 0.00957 g/sq. in., 0.015489 g/sq. in., 0.026552 g./sq. in., and 0.66380 g./sq. in., respectively. None of these cards with a full face metal foil material were able to achieve coupling with the card reader at any distance, indicating total blockage of RF communication between the card and the ISO compliant reader for all thicknesses of aluminum foil practically available commercially.

[0045] In this example, three cards with three different cutout patterns in the otherwise full-face aluminum foil were produced and tested. The foil thickness was 0.22 mils and the metal weight/area was 0.00957 g/sq. in. for all cards. The design model for each card was as follows:

[0046]

	Layer 1	Republic Foil aluminum foil: 0.22 mils
	Layer 2	Klockner Pentaplast SB6 vinyl film: 1.5 mils
	Layer 3	Klockner Pentaplast printed white vinyl
		corestock: 6 mils
	Layer 4	Micropass L4-2G RF inlay: 15 mils
	Layer 5	Klockner Pentaplast printed white vinyl
		corestock: 6 mils
	Layer 6	Klockner Pentaplast SB6 vinyl
		overlay film: 1.5 mils

[0047] The card 26 in FIG. 8 is representative of the first card evaluated in this example. The metal foil material is patterned with a cutout 28 that is shaped, sized and located to conform to the windings of the antenna 24. It was found that this card is capable of coupling with the card reader up to a distance of 4.0 cm, which is a maximum distance that is within the ISO 14443 range for an RF proximity card. The maximum coupling distance was the same regardless of whether the foil side of the card was facing toward or away from the card reader.

[0048] The card 30 in FIG. 9 is representative of the second card evaluated in this example. The metal foil material is patterned with cutouts 32 that are shaped as notches that cross the windings of the antenna 24. It was found that this card is capable of coupling with the card reader up to a distance of 2.0 cm, which is a maximum distance that is within the ISO 14443 range for an RF proximity card. The maximum coupling distance was the same regardless of whether the foil side of the card was facing toward or away from the card reader.

[0049] The card 34 in FIG. 10 is representative of the third card evaluated in this example. The metal foil material is patterned with cutouts 36 that are shaped as slits that cross the windings of the antenna 24. It was found that this card is capable of coupling with the card reader up to a distance of 2.0 cm, which is a maximum distance that is within the ISO 14443 range for an RF proximity card. The maximum coupling distance was the same regardless of whether the foil side of the card was facing toward or away from the card reader.

[0050] Based on this example, it would be expected that other cutout patterns in the metal foil material would produce similarly acceptable coupling distances. The shape, size, orientation and number of such patterns may be determined by routine experiment using the guidance provided by the present disclosure.

II. Examples Based on Metallized Film Cards

[0051] The following examples are all based on cards whose metallic foil layers include metallized film. Three different types of metallized film were used with varying numbers of layers to adjust the metal content. One metallized film was an aluminum metallized PET film, product designation PL10, from Composecure LLC. The two other metallized films were aluminum films from JDSU Corporation, product designations JDSU WS08-225 and JDSU WS07-253. Three different types of RF inlay were also used. One RF inlay was obtained from Inside Contactless Corporation, product designation Micropass L4-2G. The card 20 shown in FIG. 7 illustrates the shape of the antenna for this RF inlay. Another RF inlay was obtained from Inside Contactless Corporation, product designation Micropass L4-2.5G. The card 38 shown in FIG. 11 illustrates the shape of the antenna for this RF inlay (shown by reference number 40). The third RF inlay was obtained from Texas Instruments, Corporation, product designation CLOA-PPPC060202-170408. The card 42 shown in FIG. 12 illustrates the shape of the antenna for this RF inlay (shown by reference number 44). The plastic layers were constructed using PVC overlay film and corestock materials obtained from Klockner Pentaplast GmbH.

[0052] In this example, multiple cards with different numbers of metallized film layers were evaluated to determine how maximum RF coupling distance changed as the metal content increased. For cards with two or more metallized film layers, one set of cards had metallized film on only one side of the card and another set of cards had metallized film on both sides of the card. The design model for the two-sided metallized film cards is shown below. The one-sided metallized film cards were of the same construction but lacked layer 5:

[0053]

	Layer 1	Composecure PL10 aluminum metallized PET film
		with bonded vinyl layers: zero or more layers @
		10 mils per layer
	Layer 2	Klockner Pentaplast SB6 vinyl film
		with adhesive: 1.5 mils
	Layer 3	Micropass L4-2G RF inlay: 15 mils
	Layer 4	Klockner Pentaplast SB6 vinyl film
		with adhesive: 1.5 mils
	Layer 5	Composecure PL10 aluminum metallized PET film
		with bonded vinyl layers: zero or more layers @
		10 mils per layer

[0054] Each metallized film layer was calculated to have a metal thickness of 80 Angstroms (based on published data relating opacity to thickness for metallized aluminum film) and a metal weight/area of 0.000014 g/sq. in. (based on the density of aluminum). The maximum RF coupling distances for each card were as follows:

[0055]

			Coupling	Coupling
Number of	Metal	Metal	Distance	Distance
Metallized	Thickness	Weight/Area	(cm) Foil -	(cm) Foil -
Film Layers	(Angstroms)	(g/sq. in.)	One Side	Two Sides
0	0	0	6.0	6.0
1	80	0.000014	5.8	—
2	160	0.000028	5.5	5.5
3	240	0.000042	5.0	4.4
4	320	0.000055	4.2	4.3
5	400	0.000069	3.6	3.9
6	480	0.000083	3.4	3.2
7	560	0.000097	3.0	2.1
8	640	0.000111	2.7	2.0
9	720	0.000125	No Coupling	No Coupling

[0056] In the case of this experiment, a primary factor in the measured coupling distances is the inlay characteristics. Without any metal layer involvement, the baseline performance of the inlay in the card samples allows it to couple with the ISO compliant reader at distances of 6.0 cm or less (a maximum coupling distance of 6.0 cm.) Based on the foregoing data, it is estimated that the no coupling point (failure to couple at any distance) of the card with the reader for this experiment was reached at a metal thickness in the card of 680 Angstroms and a metal weight/area of approximately 0.000118 g/sq. in. The estimated metal thickness and content where the card fails to couple with the reader at a distance of 4 cm and beyond was estimated to be 347 Angstroms and a metal weight/area of approximately 0.000060 g/sq. in. Insofar as the metal thickness needed to provide a decorative effect is estimated to be approximately 5 Angstroms, it can be seen that in the case of this experiment, such a card design with that minimal metal laydown, would still couple with the reader at distances of just under 6 cm and below.

[0057] In this example, the metallized aluminum film was the JDSU WS08-225 material and the RF inlay was the Inside Contactless Micropass L4-2.5G. The bottom core (substitute layer 4a/4b) was a prelaminated composite identified as JDSU WSO8-226 made of a thin 1 mil PET film bonded to a 5 mil clear PVC corestock. The card design model was based on Table 2 presented above, with the card having a single metallized film layer. The precise lay-up was as follows:

[0058]

Layer 1	Klockner Pentaplast SB6 vinyl overlay film: 1.5 mils
Layer 2a	JDSU WS08-225 metallized film: 1 mil
	(With holographic image)
Layer 2b	JDSU WS08-225 vinyl coresheet backing: 5 mils
Layer 3	Inside Contactless Micropass L4-2.5G RF Inlay:
	16 mils
Layer 4a	JDSU WSO8-226 vinyl corestock backing:
Layer 4b	JDSU WSO8-226 PET film layer: 1 mil
Layer 5	Klockner Pentaplast SB6 vinyl overlay film: 1.5 mils

[0059] The calculated metal layer thickness for layer 2a was 53 Angstroms (based on published data relating opacity to thickness for metallized aluminum film). Based on the density of aluminum, it is estimated that the metal weight/area was 0.000009147 g/sq. in. This card coupled with the ISO compliant card reader up to a distance of 7.8 cm, which is approximately 8 cm and consistent with the ISO 14443 requirements. Again, in this example, the exact distance range of coupling between the card and the ISO compliant reader is determined by the inlay performance characteristics and the metal content in the continuous metallic layer.

[0060] In this example, the metallized aluminum film was the JDSU WS07-253 material and the RF inlay was the Texas Instruments CLOA-PPPC060201-170408. The bottom core (substitute layer 4) was a Boltaron White Tru Print 3045-1796 white PVC corestock. This sheet has a full coverage of 12% Spectraflair 1500-14 Pearl in a vehicle of Apollo 510840 vinyl screen coating which was applied with a 305-mesh screen. The coating has the effect of balancing the metallized film on the top foil/corestock, thus preventing the cards from bowing. The card design model was based on Table 2 presented above, with the card having a single metallized film layer. The precise lay-up was as follows:

[0061]

Layer 1	Klockner Pentaplast SB6 vinyl overlay film: 1.5 mils
Layer 2a	JDSU WS07-253 metallized film: 1 mil
	(With holographic image)
Layer 2b	JDSU WS07-253 vinyl coresheet backing: 5 mils
Layer 3	TI CLOA-PPPC060201-170408 RF Inlay: 15 mils
Layer 4	Boltaron White Tru Print 3045-1796 vinyl corestock:
	6 mils
Layer 5	Klockner Pentaplast vinyl overlay film: 1.5 mils

[0062] The calculated metal layer thickness for layer 2a was 60 Angstroms (based on published data relating opacity to thickness for metallized aluminum film). Based on the density of aluminum, it is estimated that the metal weight/area was 0.000010355 g/sq. in. This card coupled with the card reader up to a distance of 7.8 cm, which is approximately 8 cm and consistent with the ISO 14443 requirements.

[0063] In this example, the metallized aluminum film was the JDSU WS07-253 material and the RF inlay was the Inside Contactless L4-2.5G. The card design model was based on Table 1 presented above, with the card having two metallized film layers. The precise lay-up was as follows:

[0064]

Layer 1	Klockner Pentaplast SB6 vinyl overlay film: 1.5 mils
Layer 2a	JDSU WS07-253 metallized film: 1 mil
Layer 2b	JDSU WS07-253 vinyl coresheet backing: 5 mils
Layer 3	TI CLOA-PPPC060201-170408 RF Inlay: 15 mils
Layer 4a	JDSU WS07-253 vinyl coresheet backing: 5 mils
Layer 4b	JDSU WS07-253 metallized film: 1 mil
Layer 5	Klockner Pentaplast SB6 vinyl overlay film: 1.5 mils

[0065] The calculated metal layer thickness for layers 2a and 4b were 60 Angstroms each (based on published data relating opacity to thickness for metallized aluminum film). Based on the density of aluminum, it is estimated that the metal weight/area was 0.000010355 g/sq. in. This card coupled with the ISO compliant card reader up to a distance of 5.0 cm. Again, in this example, the exact distance range of coupling between the card and the ISO compliant reader is determined by the inlay performance characteristics and the metal content in the continuous metallic layer.

[0066] Accordingly, an RF proximity financial transaction card having one or more decorative metallic foil layers has been disclosed. Although various embodiments of the invention have been described, it should be apparent that many variations and alternative embodiments could be implemented in accordance with the invention. It is understood, therefore, that the invention is not to be in any way limited except in accordance with the spirit of the appended claims and their equivalents.