Smart cards with metal layer(s) and methods of manufacture
Metal layers of a smartcard may be provided with slits overlapping at least a portion of a module antenna in an associated transponder chip module disposed in the smartcard so that the metal layer functions as a coupling frame. One or more metal layers may be pre-laminated with plastic layers to form a metal core or clad subassembly for a smartcard, and outer printed and/or overlay plastic layers may be laminated to the front and/or back of the metal core. Front and back overlays may be provided. Pre-laminated metal layers having an array of card sites, with each position having a defined area prepared for the later implanting of a transponder chip module characterized by different sized perforations and gaps around this defined area adjacent to the RFID slit(s), to facilitate the quick removal of the metal in creating a pocket to accept a transponder chip module.
1. A predominantly metal smartcard having at least contactless capability, comprising:
a laminated structure comprising three metal layers (ML 1 , ML 2 , ML 3 );
wherein:
each of the metal layers has a slit extending from an outer edge of the metal layer to an inner position thereof.
2. The smartcard of claim 1 , wherein:
each of the metal layers has a thickness in the range of 200-300 μm.
3. The smartcard of claim 1 , wherein:
the slit in a given metal layer is offset in position from the slits of the other metal layers.
4. The smartcard of claim 1 , wherein:
the slits enable each metal layer to function as a coupling frame.
5. The smartcard of claim 1 , wherein:
the slit in a bottom one (ML 3 ) of the metal layers has an extended shape.
6. The smartcard of claim 1 , wherein:
outermost ones (ML 1 , ML 3 ) of the metal layers form the finished smartcard surfaces.
7. The smartcard of claim 6 , wherein the outermost metal layers are at least one of:
etched or laser patterned;
coated by pulsed vapor deposition (PVD);
coated with a suitable primer to facilitate direct printing of graphics onto the metal surface; and
screen printed and lacquered to bear artwork.
8. A smartcard having at least contactless capability, comprising:
a transponder chip module (TCM); and
a lamination subassembly (SAS) comprising at least two coupling frames (CF 1 , CF 2 );
wherein:
a first one of the coupling frames (CF 1 ) comprises a first module opening (MO 1 ) for the transponder chip module, and a first slit (S 1 ) extending from an edge of the first coupling frame to the first module opening; and
a second one of the coupling frames (CF 2 ) comprises an extended slit (S 2 ) and no module opening.
9. The smartcard of claim 8 , wherein:
the second slit (S 2 ) is offset in position from the first slit (S 1 ).
10. The smartcard of claim 8 , wherein:
the first and second coupling frames mutually support one another after lamination, particularly in regions of the card near the respective slits (S 1 , S 2 ).
11. The smartcard of claim 8 , wherein:
the first and second coupling frames each have a thickness of approximately 200 μm.
12. The smartcard of claim 8 , wherein:
the transponder chip module comprises 6 or 8 contact pads.
13. The smartcard of claim 8 , further comprising:
a front clear plastic overlay (OL) disposed atop the coupling frames.
14. The smartcard of claim 13 , further comprising:
a front plastic printed core layer (PCL) disposed between the front clear plastic overlay and the coupling frames.
15. The smartcard of claim 14 , further comprising:
an inner plastic layer (IPL) disposed between the front plastic printed core layer (PCL) and the coupling frames.
16. The smartcard of claim 15 , wherein:
the front clear plastic overlay (OL) has a thickness of approximately 50 μm;
the plastic printed core layer (PCL) has a thickness of 75-125 μm; and
the inner plastic layer (IPL) has a thickness of 20-100 μm.
17. The smartcard of claim 8 , wherein:
the second coupling frame with extended slit prevents distortion of rear printed layers and overlays of the card in a region of the second coupling frame which is cut out to accept embedding of the transponder chip module.
18. The smartcard of claim 8 , wherein:
the extended slit (S 2 ) has a width which varies along its length.
19. The smartcard of claim 8 , wherein:
the transponder chip module comprises a module antenna (MA); and
the extended slit (S 2 ) overlaps or runs adjacent to or is in close proximity with the module antenna.
20. The smartcard of claim 19 , wherein:
the extended slit (S 2 ) describes a nearly complete loop that permits passage of alternating electromagnetic fields though the coupling frames (CF 1 , CF 2 ) and the transponder chip module (TCM).
21. The smartcard of claim 19 , wherein:
the shape of the extended slit (S 2 ) is such as to direct eddy currents induced in the second coupling frame (CF 2 ) into close proximity with the module antenna (MA) and into the same direction or sense, locally around the transponder chip module (TCM) area, as the induced eddy current paths in the first coupling frame (CF 1 ).
22. The smartcard of claim 8 , wherein:
the extended slit (S 2 ) is designed to reside over a void usually formed by the creation of a module opening (MO) in a coupling frame (CF).
23. Method of making a smartcard, comprising:
providing a lamination subassembly (SAS) comprising at least two coupling frames (CF 1 , CF 2 ), wherein:
a first one of the coupling frames (CF 1 ) comprises a first module opening (MO 1 ) for the transponder chip module, and a first slit (S 1 ) extending from an edge of the first coupling frame to the first module opening; and
a second one of the coupling frames (CF 2 ) comprises an extended slit (S 2 ) and no module opening;
thereby preventing the formation of a visible defect or depression on the rear of a smartcard.
24. The method of claim 23 , further comprising:
an insert placed within the module opening in order to support plastic layers applied in subsequent lamination and/or to support the transponder chip module (TCM) in the final smartcard.
25. The method of claim 24 , wherein:
the insert is a plastic material, and facilitates ease of milling the module opening.