GB2371263A

GB2371263A - Forming a low frequency contact-less smart card with an antenna coil

Info

Publication number: GB2371263A
Application number: GB0101316A
Authority: GB
Inventors: Chi Keung Lee; Kwok Lam Kwan
Original assignee: Pioneer Oriental Engineering Ltd
Current assignee: Pioneer Oriental Engineering Ltd
Priority date: 2001-01-18
Filing date: 2001-01-18
Publication date: 2002-07-24
Also published as: GB0101316D0; TWI222600B

Abstract

Milled trough 14 and punched cavity 16 are formed on major surface 12 of core sheet 10. Antenna coil 20 is joined to integrated circuit (IC) 22 by soldering of wire coil 20 and the antenna is then implanted into the trough and the IC implanted into the cavity (see Fig 5). The card can then be laminated with outer sheets (24, 26, Fig 6) and smart card or IC card (30, Fig 7) can be punched from the resulting card panel (28, Fig 7). Trough 14 can also be formed by punching, in which case a backing sheet would be secured to the core sheet and the antenna coil secured by adhesive to the backing sheet. A thinner card can be produced by this process to comply with international standards of card thickness. A low frequency contact-less smart card with an antenna coil can be used for paying highway tolls as it can pick up radio signals from a relatively long distance.

Description

An IC Card and a Method of Forming an IC Card This invention relates to a method of forming a card embedded with at least one integrated circuit, generally known as an"IC Card"or"Smart card". The invention also relates to such an IC card.

Cards have long been used as a data carrier. Ordinary cards may carry data visually, e. g. having information or the like printed or written on one or both major surfaces of the card.

Cards may also act as magnetic data carriers in the form of magnetic cards. In magnetic cards, a magnetic strip is pressed on a particular location of a card. The magnetic strip carries data which are readable by a magnetic data reader. Magnetic cards may be used as train tickets, bank cards etc.. Such magnetic cards, however, suffer from the drawback that the amount of data which can be carried or stored by a magnetic strip is small. In addition, magnetic cards can only be over-written a relatively small number of times, and are easily damaged. Magnetic cards are also prone to be affected by magnetic fields in the environment, and may even lose the data stored therein.

As an improvement over the above conventional data-carrying cards,"smart cards"or "IC cards"have been provided. Such are cards embedded with an integrated circuit (IC) for

storing data. With existing technology, an IC can store over 30k byte of data, and can be over-written and read for over 100, 000 times. As the IC can contain both the data and the programme, the smart cards can be used remote of a computer terminal. IC cards are used as telephone cards or credit cards. Such cards sometimes also include a magnetic strip, thus providing two interfaces.

IC cards may be generally classified as contact cards and contact-less cards. For contact cards, at least a major surface of the IC with a read/write interface is exposed to the outside environment. When in use, the read/write interface of the IC card is in direct physical contact with a read/write head of a computer terminal or processor, whereby data may be written into

and/or read from the IC in the card. On the other hand, a contact-less card is provided with coils of a copper wire, which is secured at or adjacent to its two ends with the IC, which is fully embedded within the IC card. The coil of copper wire acts as an antenna for transmitting and/or receiving radio frequency signals. The IC may then be coupled to an external system, e. g. a computer system, by radio frequency (RF) transmission. In this case, the IC needs not be in direct contact with any read/write head of the external computer system.

If a contact IC card is frequently used, say once or twice a day or more, the IC of the card will be easily damaged. In certain circumstances, the use of contact cards will also be more time-consuming. For example, for paying highway toll, the use of contact cards will mean that each car passing through a toll counter will have to stop for processing payment. Contact-less cards are thus appropriate for use in transactions which are relatively frequent but involve relatively small amount of money.

Contact-less IC cards may be further classified as high-frequency contact-less IC cards and low-frequency contact-less IC cards. The operating frequency of a high-frequency contact-less IC card (also called a high-frequency card) is 13. 56MHz, while that of a lowfrequency contact-less IC card (also called a low-frequency card) is 125kHz. A highfrequency card is provided with a coil of 4 to 5 rounds of copper wire, and the operation distance is within roughly 10cm. The chance of a high-frequency card accidentally affecting, or being affected by, the operation of other nearby high-frequency cards is small, and is thus very reliable. For a low-frequency card, such is provided with a coil of 250 to 300 rounds of a copper wire. While the manufacture of low-frequency cards is rather complicated and not readily susceptible to automation, its main advantage is that its operation distance may be up to 3m.

High-frequency cards are usually adopted for personal use, e. g. for travelling on trains or buses. As to low-frequency cards, such may be used for paying highway tolls, as the radio frequency signals can be transmitted through a long distance and it is relatively easy to differentiate between different cars.

According to the applicable international standard, the thickness of such a card should be 0. 76 : t0. 08mm. However, in particular for low-frequency contact-less cards, such a standard can seldom be achieved. Usually, the cards are of a thickness of over 0.84mm, the reason being that the antenna coil is too thick.

It is thus an object of the present invention to provide an IC card, and a method of forming such an IC card, in which the aforesaid shortcoming is mitigated, or at least to provide a useful alternative to the public.

According to a first aspect of the present invention, there is provided a method of forming a card embedded with at least one integrated circuit and an antenna coil, said method including the steps of (a) forming a first cavity on a sheet; (b) forming a second cavity on said sheet; (c) positioning at least part of said integrated circuit into said first cavity of said sheet; and (d) positioning at least part of said antenna coil into said second cavity of said sheet.

According to a second aspect of the present invention, there is provided a card embedded with at least one integrated circuit and an antenna coil, wherein said card includes at least one sheet with a cavity receiving at least part of said antenna coil.

An embodiment of the present invention will now be described, as an example only, with reference to the accompanying drawings, in which : Fig. 1 shows a core sheet provided with a trough for receiving an antenna coil, according to the present invention; Fig. 2 shows a cross sectional view of the core sheet taken along the line A-A in Fig. 1 ; Fig. 3 shows the punching of a cavity in the core sheet for receiving an IC according to the present invention;

Fig. 4 shows the positioning of the antenna coil and the IC into the core sheet shown in Fig.

3 ; Fig. 5 shows the antenna coil and the IC as positioned into the core sheet shown in Fig. 3 ; Fig. 6 shows the piling together of sheets for lamination according to the present invention; and Fig. 7 shows the punching out of a product card from the laminated panel according to the present invention.

As shown in Figs. 1 and 2, a core sheet 10 is provided on a major surface 12 thereof with a trough 14 for receiving an antenna coil, to be discussed below. The trough 14 is formed by milling. A cavity 16 is then formed by a punching machine or a punch tool 18, as shown in Fig. 3. In the production of low-frequency contact-less cards, an antenna coil 20 (which is made up of 250 to 300 rounds of a copper wire) is already secured and electrically connected with an integrated circuit (IC) chip 22, as shown in Fig. 4. Such may be effected by soldering two ends of the wire coil 20 with the IC 22.

The antenna coil 20 and the IC chip 22 are then implanted into the core sheet 10, as

shown in Fig. 5, in which the antenna coil 20 is received in the trough 14 and the IC chip 22 is received within the cavity 16. An adhesive which is compatible with the material of which the core sheet 10 is made may be applied on the bottom surface of the trough 14 for securing of the antenna coil 20 within the trough 14. It is found in practice that it is desirable that, before lamination, the depth of the trough 14 is smaller than the thickness of the antenna coil 20 by 0.1 to 02. mm. With such an arrangement, after lamination, the antenna coil 20 will be fully received within the trough 14, and will not take up any thickness in the final product.

For the purpose of lamination, the core sheet 10 is positioned between and aligned with various outer sheets 24,26. Although only two outer sheets 24,26 are shown, it should be understood that more outer sheets may be employed. Such outer sheets 24,26 may include filler sheets, protective sheets, graphical printing sheets, and outer transparent sheets, depending on the purpose of the product card.

When the outer sheets 24,26 and the core sheet 10 are properly piled up and aligned with one another, such will be spot-welded to ensure that they will remain at the proper relative position during lamination. During lamination, the piled up and aligned core sheet 10 and outer sheets 24,26 will be secured with one another under pressure and high temperature in the lamination machine, to form a laminated card panel 28. A product IC card 30 may then be cut out from the card panel 28 by punching.

Alternatively, a cavity for receiving the antenna coil 20 may be formed on the core sheet 10 by punching. In this way, a through-hole is formed in the core sheet 10. The core sheet 10 may then be secured, e. g. by adhesive, to a backing sheet. Adhesive may be applied on the area of the backing sheet exposed through the through-hole of the core sheet 10. The antenna coil 20 may then be secured within the through-hole of the core sheet 10, by being adhered onto the backing sheet.

It should be understood that the above only illustrates an example whereby the present invention may be carried out, and that various modifications and/or alterations may be made thereto without departing from the spirit of the invention.

It should also be understood that various features of the invention which are, for brevity, described in the context of a single embodiment, may be provided separately or in any appropriate sub-combinations.

Claims

CLAIMS :1. A method of forming a card embedded with at least one integrated circuit and an antenna coil, said method including the steps of (a) forming a first cavity on a sheet; (b) forming a second cavity on said sheet; (c) positioning at least part of said integrated circuit into said first cavity of said sheet; and (d) positioning at least part of said antenna coil into said second cavity of said sheet.
2. A method according to Claim 1 wherein the thickness of said antenna coil is larger than the depth of said second cavity by substantially 0.1 to 0.2mm.
3. A method according to Claim 1 or 2 wherein said integrated circuit is electrically connected with said antenna coil before said integrated circuit is positioned into said first cavity of said sheet.
4. A method according to any of the preceding claims wherein said integrated circuit is secured with said antenna coil before said integrated circuit is positioned into said first cavity of said sheet.
5. A method according to any of the preceding claims wherein an adhesive is applied within at least part of said second cavity.
6. A method according to any of the preceding claims including a step (e) of positioning said sheet between at least two outer sheets for lamination.
7. A method according to Claim 6 further including a step (f) of punching at least one product IC card from the laminated sheets.
8. A card embedded with at least one integrated circuit and an antenna coil, wherein said card includes at least one sheet with a first cavity receiving at least part of said antenna coil.
9. A card according to Claim 8 wherein said sheet includes a second cavity for receiving at least part of said integrated circuit.
10. A card according to Claim 8 or 9 wherein said sheet is positioned between at least two outer sheets.
11. A card according to any one of Claims 8 to 10 wherein said card is a low-frequency contact-less IC card.
12. A card substantially as herein described and shown in the accompanying drawings.