Active solid-state devices (e.g. – transistors – solid-state diode – Integrated circuit structure with electrically isolated... – Passive components in ics
Reexamination Certificate
2002-09-25
2004-09-21
Graybill, David E. (Department: 2827)
Active solid-state devices (e.g., transistors, solid-state diode
Integrated circuit structure with electrically isolated...
Passive components in ics
C257S679000, C257S783000, C438S111000, C438S062000, C438S238000
Reexamination Certificate
active
06794727
ABSTRACT:
The present invention relates to the field of portable objects such as, in particular, contactless electronic labels and chip cards provided with an electronic module comprising an integrated microcircuit.
The invention also relates to a process for manufacturing such modules and such portable objects.
Portable objects are already known in the form of contactless cards, of ISO format, which are intended to perform various operations such as, for example, payment operations for transport, telephone or other services. These operations are conducted by means of remote coupling between the card's electronic module and a receiver or reader unit. Coupling may be made in reading mode only or in reading/writing mode.
In respect of cards, it is to be noted that the invention does not only concern cards which operate exclusively without contact. It also relates to mixed or hybrid cards which are able to operate in both modes: without and with contact. These mixed cards are intended, for example, for operations of electronic cash dispensing type for which, after being charged with units of value (monetary units, payment units for various services) they are remote debited by a certain number of these units of value when they are passed in the proximity of a reading terminal: this type of debiting assumes contactless operation. If required, these cards can be re-charged in a purpose-designed dispenser.
For the needs of the present disclosure, and for simplification purposes, contactless cards shall be construed as meaning both mixed cards and contactless cards.
Also portable items are known in the form of electronic labels, generally used for various identification or follow-up operations. They are made up firstly of an electronic module with a microcircuit, and secondly of a carrier for this module associated with a coiled antenna operating at relatively low frequency (150 Khz) and of relatively large size in relation to the size of the module.
Such as they are currently produced, portable objects in the form of electronic labels comprise antennae having a large number of turns, often over 100, and their size makes their handling difficult, especially during the label production stages when the antenna is connected by welding to the module's microcircuit.
Similarly, portable objects in the form of contactless cards also have disadvantages. Such as they are currently produced, contactless cards are portable objects of normalized size. A usual, but in no way restrictive, standard for the present invention is the so-called ISO 7810 standard which corresponds to a card of standard format 85 mm long, 54 mm wide and 0.76 mm thick.
In most known contactless cards, each card comprises a card body made up of an assembly of plastic sheets and of an electronic module, embedded in this assembly, comprising an integrated circuit or microcircuit also called a <<chip>> connected via two connection terminals to a coiled antenna of self-inductance type. The chip has a memory and may, in some cases, comprise a microprocessor. The size of the electronic module is substantially smaller than the size of the card, the module generally being positioned in one of the corners of the card, since the mechanical stresses exerted on the module through bending of the card are not as high in the corners as in the centre of the card.
In some known contactless cards, however, provision is made in the card body for a cavity, and provision is made for a module fitted with a coil connected to an integrated circuit, to enable contactless operation of the card.
In this category of contactless cards, an assembly unit is particularly known after DE-A-43 11 493 (AMATECH), for the production of identification units in card format.
According to a first embodiment, a module
21
comprises a module carrier
28
on which is fixed an integrated circuit chip
29
. A coil
30
surmounts chip
29
in such manner as to confer contactless identification capacity upon the module. This document specifies that the reading distance between the module and the contactless reader is small. Also, to date no chip card using such a module with antenna has apparently been marketed given the problems of cost and small range which necessarily arise with the described module structure.
Also, it is to be noted that in this document the antenna is in the form of a coiled air antenna inserted over the chip which gives rise to difficulties relating to production, cost, yield and lack of homogeneous performance.
Also, after DE 37 21 822 C1 (PHILIPS) a chip card operating without contact is known, whose design is intended to solve a problem of poor connection between the coil and the integrated circuit. For this purpose, this document describes a chip card without a module, an antenna
4
being fabricated on the semiconductor itself on which an integrated circuit
5
is made. The antenna is made at the same time as the upper tracks of the integrated circuit so that the resulting integrated circuit is 4×6 to 6×8 mm
2
carrying 20 small turns.
As a result the effective surface area of the antenna is small, which is detrimental to its range. Also, the card in accordance with this document cannot be produced in economic manner. It is known that the size of an elementary semiconductor pad is one of the main cost factors for mass produced integrated circuits. In this document, however, the minimum size of the integrated circuit incorporating the antenna is of about at least 24 mm
2
, whereas cheap contactless cards generally use microcircuits of very small size, of about 1 mm
2
.
A plurality of other processes for making contactless cards are also known, such as those described in French patent applications made by the same applicant and filed under numbers 95 400305.9, 95 400365.3 and 95 400790.2. These patent applications all describe a contactless card provided with an antenna whose size is substantially the same as that of the card and is connected to a micromodule carrying the chip.
Such antenna has the advantage of having a relatively high range for a given reading or writing magnetic field. The equation which determines the electromotive force E appearing at the terminals of the receiver antenna when it breaks an electromagnetic field is of the following type:
E
r
=l
e
(
K
e
S
e
N
e
)·(
K
r
S
r
N
r
)/
D
3
(1)
in which K is a constant, S is the surface area of an average turn of antenna, N is the number of turns coiled to form the antenna, indices e and r represent the emitting and receiver sides respectively, and D is the reading distance, i.e. the distance between the card antenna and the antenna of the outside reader.
To cause the circuits of the card chip to operate in order to initialize and conduct a reading operation, voltage E must be exceed a certain threshold, which is generally in the region of 3 Volts.
It will therefore be seen that for a given reading or writing distance D that it is sought to achieve with the contactless card, the surface area of the average turn and/or the number N of antenna turns needs to be increased on the reading and/or writing side.
The efficiency of the antenna, at the chosen frequency for reading or writing, will be determined by the overvoltage coefficient of the antenna coil which is given by the equation:
Q=L&ohgr;/R
(2)
in which L is the coil inductance which increases with coil diameter and the number of turns, &ohgr;=2&pgr;f in which f is the reading frequency which is fixed for a given application, and R is the electric resistance of the antenna coil, which is proportional to the length of wire of which it is formed.
Since L and R have contrary effects on the efficiency of the antenna, they tend to offset one another so that the true efficiency factor of the antenna is especially related to the total surface area SN of the antenna.
For a given planar coil size, the number N of turns is limited by the width of a turn and the space between two turns which depend upon the technology used for fabrication.
It is therefore seen that, all o
Kalinowski Richard
Leduc Michel
Martin Philippe
Gemplus
Graybill David E.
Plottel Roland
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