Communications: radio wave antennas – Antennas – High frequency type loops
Reexamination Certificate
2002-02-04
2003-11-04
Le, Hoanganh (Department: 2821)
Communications: radio wave antennas
Antennas
High frequency type loops
C343S867000
Reexamination Certificate
active
06642896
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a reader coil antenna, and a non-contacting type card identification system using the same, and more particularly to an improved reader coil antenna which can form a magnetic field, transmit an operating frequency, and receive a frequency from a non-contacting type card in order to decode data of the non-contacting type card, and a non-contacting type card identification system using the same.
2. Description of the Related Art
Both a contacting type magnetic card having a magnetic strip portion which is rubbed for identification, and a non-contacting type card which transmits/receives data by frequency in a magnetic field space have been generally used as means for making payment. Examples of magnetic cards are credit cards and pre-paid telephone cards, while examples of the non-contacting type card are pre-paid transportation cards, and non-contacting type subway credit cards.
FIG. 1
is a block diagram illustrating a conventional non-contacting type card identification system. Referring to
FIG. 1
, the conventional non-contacting type card identification system
10
includes an antenna system
16
, a card reader
18
and a control unit
20
.
The card reader
18
generates a current to sense a non-contacting type card
14
, and transmits a magnetic field formed by the current through the antenna system
16
.
The non-contacting type card
14
manually charges a battery by the transmitted magnetic field, and transmits a signal including an internally-stored data to the antenna system
16
.
The signal received in the antenna system
16
is output to the control unit
20
through the card reader
18
.
The signal received in the control unit
20
is compared with master security information (not shown) stored in the control unit
20
to decide card identification, and is transmitted through the antenna system
16
.
Further, the antenna system
16
includes a reader coil antenna, and generates the magnetic field by the applied current to the reader coil antenna and receives the signal from the non-contacting type card
14
.
FIG. 2
is a perspective diagram illustrating a conventional reader coil antenna. As shown therein, the conventional reader coil antenna includes a driving loop antenna
22
, double loop antennas
32
,
34
and a non-magnetic conductive material
26
.
Here, the double loop antennas
32
,
34
are connected to each other in a cross-over type connection
36
. In addition, the non-magnetic conductive material
26
contains aluminum, silver, copper, brass or gold to induce the magnetic field of the driving loop antenna
22
by providing a shield against an eddy current. A driving current for driving the non-contacting type card
14
is applied to terminals
28
,
30
connected to the card reader
18
. The magnetic field is generated in the driving loop antenna
22
due to the applied current. Here, an induced current is generated in the double loop antennas
32
,
34
by the driving loop antenna
22
. The induced current has a phase difference of 180° from a direction of the current flowing through the driving loop antenna
22
.
The double loop antennas
32
,
34
are adhered to the surface of the non-magnetic conductive material
26
. Accordingly, the magnetic field is generated on the front surface of the antenna system
16
where the non-contacting type card
14
is positioned, but induced and absorbed on the rear surface thereof.
In the above-described reader coil antenna, the driving loop antenna
22
and the double loop antennas
32
,
34
have the opposite current direction. It is thus difficult to increase a reading distance which is the data recognition distance between the antenna system
16
and the non-contacting type card
14
. Moreover, the non-magnetic conductive material
26
induces and absorbs the magnetic field, thus reducing strength of the magnetic field. As a result, the reading distance due to the magnetic field is further shortened.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a reader coil antenna which can increase the reading distance, where a non-contacting type card is read, due to strength of an internal magnetic field, and a non-contacting type card identification system using the same.
In one aspect of the present invention, a reader coil antenna of a non-contacting type card identification system includes: an outer coil forming a predetermined loop, and forming a magnetic field by receiving a current; and at least one inner coil disposed inside the loop of the outer coil, for generating a constructive interference in a direction of the magnetic field of the outer coil by receiving a current.
In another aspect of the present invention, a non-contacting type card identification system using a reader coil antenna includes: the reader coil antenna for forming a magnetic field due to a signal applied to flow in an identical direction; a card reader for transmitting an operating signal through the reader coil antenna, and decoding an input signal from a non-contacting type card; and a control unit for deciding identification of the non-contacting type card according to the decoded signal.
According to the present invention, a sensing region of the center portion of the coil is increased due to the reader coil antenna provided with the identical direction current. In addition, strength of the magnetic field is increased near the center portion of the coil, by inserting a non-conductive magnetic material into the inner coil. As a result, the sensing region is increased, communication reliability is improved, and a dead zone is reduced.
REFERENCES:
patent: 4857893 (1989-08-01), Carroll
patent: 5541399 (1996-07-01), de Vall
patent: 6165567 (2000-12-01), Ventzek et al.
patent: 6176433 (2001-01-01), Uesaka et al.
patent: 6385407 (2002-05-01), Inose
patent: 2002/0089049 (2002-07-01), Leduc et al.
patent: 2003/0025186 (2003-02-01), Leduc et al.
patent: 197 01 167 (1998-07-01), None
patent: 0 948 083 (1999-10-01), None
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