PROXIMITY AND DUAL INTERFACE METAL CARDS AND METHODS OF MAKING CARD BODIES WITH TWO METAL LAYERS
Proximity cards or contactless smartcards manufactured by folding a metal layer along one or two fold lines to form a metal card body (MCB) having the dimensions of a standard ID-1 smartcard. An antenna structure (AS) on a flexible or rigid circuit sandwiched powering an RFID chip may be disposed between the folded metal layer or metal layers. A smartcard (SC) characterized by a booster antenna (BA) arranged on a rear plastic layer laminated to a front metal layer (ML) having a slit (S). A sense coil (SeC) component may be arranged around the slit, and may overlap the slit in a zigzag fashion or the like. The sense coil may have a loop, spiral or helix shape. The booster antenna may form a closed loop circuit or an open loop circuit.
1 . A method of making a card body (CB) for an RFID device of a given size, comprising:
providing an oversize metal layer (OML) having a full size middle portion (MP) flanked by two half size side portions (SP) extending from opposite side edges of the middle portion; and
folding the two side portions, towards each other, over the middle portion so that their outer edges (oe) oppose and nearly touch each other, leaving a slit (S) therebetween.
2 . The method of claim 1 , further comprising:
providing an insulating layer between the middle portion and the side portions.
3 . The method of claim 1 , further comprising:
providing a full size module opening (fMO) in the middle portion; and
providing a half size module opening (hMO) in each of the side portions.
4 . The method of claim 3 , wherein:
when the side portions are folded over the middle portion, the half size module openings oppose each other, and together form a full size module opening.
5 . The method of claim 1 , further comprising:
providing a slit (S) in the middle portion.
6 . The method of claim 1 , further comprising:
after folding, trimming one of the outer edges.
7 . The method of claim 1 , wherein:
the RFID device is a smartcard (SC) or a proximity card (PC).
8 . The method of claim 1 , wherein:
the middle portion represents a first metal layer (ML- 1 );
the folded over side portions represent a second metal layer (ML- 2 ); and
further comprising disposing an RFID chip module between the two metal layers.
9 . The method of claim 8 , wherein:
both metal layers have a slot to accept a lanyard.
10 . The method of claim 8 , further comprising:
providing an antenna structure which is adjacent to or overlaps the slit.
11 . A smartcard comprising:
a coupling frame (CF) comprising a metal layer (ML) with a slit (S); and
a booster antenna (BA).
12 . The smartcard of claim 11 , wherein:
the booster antenna comprises a sense coil (SeC) disposed in, or across, or overlapping the slit, including an area adjacent to the slit.
13 . The smartcard of claim 11 , further comprising:
ferrite disposed between the booster antenna and the coupling frame.
14 . The smartcard of claim 11 , wherein:
the smartcard is a contactless smartcard, or is a dual interface (contactless and contact) smartcard.
15 . The smartcard of claim 11 , wherein the booster antenna comprises:
a perimeter coil (PC) component extending around a peripheral area of the card body, and having one or more turns;
a coupling or coupler coil (CC) component located at the module opening for coupling with an antenna (MA) in the transponder chip module, and having one or more turns; and
a sense coil (SeC) component located at an area of the slit.
16 . The smartcard of claim 15 , wherein:
the sense coil has a zigzag, loop, helical or spiral shape.
17 . The smartcard of claim 15 , wherein:
the sense coil crosses over the slit several times, perpendicular to and overlapping the slit.
18 . The smartcard of claim 15 , wherein:
the sense coil traverses back and forth (meanders) in the slit, parallel to the slit.
19 . The smartcard of claim 15 , wherein:
the sense coil (acting like a pickup coil) interacts/couples with the coupling frame, at the location of the slit, and comprises one or more of the following:
the sense coil comprises embedded wire, and traverses the slit a number of times, generally perpendicular to the slit, including an area outside of the slit;
the sense coil comprises embedded wire, and zigzags, extending generally parallel to the slit, including an area outside of the slit;
the sense coil comprises embedded wire in the form of a spiral, or the like, overlapping the slit; and
the sense coil comprises a conductive track, or “ribbon”, such as in US 2018/0341847, and extends parallel inward, cross the slit, and extend parallel outward, including overlapping an area outside of the slit.
20 . The smartcard of claim 11 , wherein:
the booster antenna comprises wire embedded in a plastic layer (PL); and
further comprising ferrite disposed between the plastic layer and the coupling frame.