« PreviousContinue »
(12) United States Patent
(io) Patent No.: (45) Date of Patent:
US 7,271,039 B2 *Sep. 18, 2007
(54) METHOD FOR MANUFACTURING
DEVICE USING TRANSFER PAPER AND
DEVICE PRODUCED USING THIS METHOD
(75) Inventor: Christophe Halope, Cannes (FR)
(73) Assignee: ASK S.A., Valbonne (FR)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 192 days.
This patent is subject to a terminal disclaimer.
(21) Appl. No.: 11/126,314
(22) Filed: May 11, 2005
(65) Prior Publication Data
US 2005/0230486 Al Oct. 20, 2005
Related U.S. Application Data
(63) Continuation-in-part of application No. 10/333,022, filed as application No. PCT/FR02/01625 on May 14, 2002, now Pat. No. 6,908,786.
(30) Foreign Application Priority Data
May 16, 2001 (FR) 01 06480
(51) Int. CI.
H01L 21/48 (2006.01)
H01L 21/50 (2006.01)
(52) U.S. CI 438/127; 438/125; 257/E21.502
(58) Field of Classification Search 438/25,
438/26, 51, 55, 64, 106, 110, 125, 126, 127;
A method for manufacturing a radiofrequency identification device which includes a manufacturing process for an antenna which includes screen-printing turns of an electrically conductive polymer ink onto a transfer paper sheet, and then subjecting the support to heat treatment to bake and polymerize the conductive ink, connection of a chip 14, provided with contacts, to the antenna 12, lamination which includes making the transfer paper sheet integral with a layer of plastic material 16 which constitutes the support for the antenna, by hot press molding, in such a way that the screen-printed antenna and the chip are both embedded within the layer of plastic material, and removal of the transfer paper sheet.
METHOD FOR MANUFACTURING
DEVICE USING TRANSFER PAPER AND
DEVICE PRODUCED USING THIS METHOD 5
This application is a continuation-in-part of U.S. application Ser. No. 10/333,022, filed on Jan. 15, 2003 now U.S. Pat. No. 6,908,786, and which is the U.S. National Stage of International application PCT/FR02/01625, filed May 14, 10 2002.
This invention concerns the field of smart cards (or 15 tickets), and more particularly a manufacturing method for a radiofrequency identification device (RFID).
Smart cards and tickets, and more particularly ISO format cards, have become extremely widespread in recent years. Above and beyond their use as credit cards, smart cards have become indispensable tools in many areas. This growth is largely due to the fact that, in addition to the traditional use 25 of cards which make contact with the appropriate reader (e.g. bank and telephone cards), the new cards can be used without any physical contact with the reader.
The exchange of information between the contactless card or hybrid contact-contactless card and the associated reader 30 is accomplished by remote electromagnetic coupling between an antenna integrated into the contactless card and a second antenna located in the reader. In order to create, store and process the information, the card is provided with a chip which is connected to the antenna. The antenna is 35 generally located on a dielectric support made of plastic material. This ease of use has made the development of many other applications possible. For example, the development of the electronic wallet. In the transportation sector, smart cards have been developed as a means of paying 40 highway tolls. At events, smart cards can be used by supporters as a season ticket for venues. For security applications, many companies have set up systems for staff identification based on ISO contactless smart cards.
The conventional contactless cards found on the market 45 consist of several layers of plastic material, notably polyvinyl chloride (PVC). One of these layers constitutes the support for the antenna, and the others generally constitute the body of the card. The card's antenna is most commonly a copper wire or is chemically etched onto the card. 50
However, the production of such cards is relatively expensive. This is because the use of copper and etching processes are both expensive. Moreover, producing such an antenna on a PVC support necessarily entails using sophisticated—and therefore expensive—machinery. 55
Now, the development of contactless technology is dependent on a reduction in the manufacturing costs for such cards. One way of reducing production costs involves cheaper manufacturing methods for the antenna, notably by creating it using a screen-printing process with a conductive 60 ink.
However, screen-printing on PVC is associated with a number of drawbacks. Furthermore, PVC exhibits poor thermomechanical properties. During the card body lamination process, material flow is significant and the antenna's 65 shape factor is not maintained. Before lamination, when the conductive ink used to create the antenna is drying, the
temperature is higher than that at which the plastic material becomes soft so there is deformation of the support which affects the antenna's electrical performance. This leads to antenna malfunction as electrical parameters (inductance and resistance) vary. Even more serious, it is not uncommon to experience antenna breakage in areas where strong sheer stresses are present. Moreover, it is impossible to replace the thermoplastic material with a thermosetting one since the latter is not amenable to hot lamination.
Another disadvantage is that, when the antenna is screenprinted onto PVC, connecting the chip to the antenna is much more difficult.
SUMMARY OF THE INVENTION
The purpose of the invention is thus to overcome these drawbacks by providing a manufacturing method for producing a radiofrequency identification device (RFID) such as a contactless smart card, made of plastic, with an antenna created by screen-printed ink, with a low cost price but which is nevertheless very reliable.
The invention thus concerns a method for manufacturing a radiofrequency identification device which includes the following steps:
a manufacturing process for the antenna consisting in screen-printing turns of electrically conductive polymer ink on a transfer paper sheet, and then subjecting said support to heat treatment in order to bake and polymerize said conducting ink, connection of a chip, provided with contacts, to the antenna,
lamination consisting in making the transfer paper sheet integral with a layer of plastic material which constitutes the antenna support, by hot press molding, in such a way that the screen-printed antenna and the chip are both embedded within the plastic material, and removal of the transfer paper sheet. Another object of the invention is a radiofrequency identification device such as a smart card, generated by the method according to the invention, which includes an antenna support made of a plastic material and at least one layer of plastic material on either side of the antenna support constituting the body of the card, in which both the screenprinted antenna and the chip are embedded in the antenna support.
BRIEF DESCRIPTION OF THE DRAWINGS
The purposes, objects and characteristics of the invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which:
FIG. 1 shows a side view of a sheet of transfer paper bearing a screen-printed antenna and a chip connected to this antenna.
FIG. 2 shows a longitudinal section through axis A-A of the transfer paper sheet as shown in FIG. 1.
FIG. 3 shows a longitudinal section through the transfer paper sheet in contact with the plastic antenna support after a lamination step.
FIG. 4 shows a longitudinal section through the antenna support after removal of the transfer paper sheet.
FIG. 5 shows a longitudinal section through the finished card according to one of the applications of the invention.