Registers – Records – Conductive
Reexamination Certificate
1999-10-27
2001-01-16
Pitts, Harold I. (Department: 2876)
Registers
Records
Conductive
C343S720000
Reexamination Certificate
active
06173900
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an antenna member (hereinafter also referred to as an antenna part material). The antenna member according to the present invention is useful to be applied to a so-called IC card. Particularly, the present invention relates to the art durable for use of a plurality of antenna members piled up with or without intention.
2. Description of the Related Art
Lately, an IC card has been developed which embeds an IC chip (a semiconductor integrated circuit element) and an antenna for wireless transmission and reception of data. These are intended to be widely utilized, for example, for a commutation ticket and a coupon ticket in various transport facilities, a telephone card, an in-and-out card to room, an ID card, a license, or a music ticket, etc. Further typical use of the card intended includes the object for pachinko, a card for recreational facilities such as an amusement park, a theater, and so on, for a medical use, or for various applications of self-governing communities, etc. Thus, the present invention can be applied to these various cards.
As a typical example of an antenna member according to the present invention, there is provided a so-called IC card.
FIG. 1
shows a contactless type IC card as one example thereof.
FIG. 1
is a plan view showing a conception of the IC card, showing an arrangement of an IC chip
2
and an antenna embedded in an IC card
1
. The number of windings of an antenna coil is simplified in the drawing for better understanding of an explanation. In the drawings, for example,
FIGS. 9
,
12
,
13
,
14
,
15
and
16
, showing a card with the similar conception described below, to which similar simplification is likewise applied.
FIG. 2
is an explanatory view showing a usage pattern thereof. In this example, an IC card
4
is not always in contact with a data writer-reader
5
(normally called a reader/writer), and exchanges information by an induction electromagnetic field in communication with an antenna
7
embedded in the IC card
4
. Because of this reason, the card of this type is called a contactless type. Within the frame indicated by dotted lines at the upper portion of
FIG. 2
, an antenna
6
mounted on the reader/writer
5
, and an antenna
7
and a rectifying circuit
8
mounted on the IC card
4
are illustrated.
Further, this IC card contains no battery, and a supply of power is received through the antenna
7
from the reader/writer
5
side. That is, a signal Vs from the reader/writer
5
is transmitted to the IC card through the antenna
6
. The IC card
4
side takes in this signal by the electromagnetic induction through the antenna
7
. Generally, a signal source used on the reader/writer side is 13.5 MHz. At this time, a signal is taken in efficiently by resonance with a resonant frequency of a value close to a signal frequency fs by inductance and condenser C of the antenna
7
. The thus taken-in signal can obtain a signal voltage Vout by the rectifying circuit
8
embedded in the IC card
4
. This signal voltage Vout is supplied to a circuit for the signal processing embedded in the IC card. The circuit used for this purpose and the aforementioned rectifying circuit are incorporated in the IC chip. In
FIG. 2
, reference numerals
10
and
10
′ each designates a reader/writer, and a communication controller included in the IC card, respectively.
The general explanation of the IC card appears, for example, on “Data Carrier (II),” Nihon-Kogyo Press, Tokyo: pp. 137-194 March 1991. Further, an IC card using a thin chip has been proposed in Japanese Patent Application Laid-Open No. Hei3-87299.
SUMMARY OF THE INVENTION
It is thus an object of the present invention to provide an IC card, wherein even if a state should occur in which antenna members, such as IC cards are piled up in any direction for use, the received power of the IC cards is not greatly lowered to secure a normal usage pattern. In the present specification, an IC card which is a typical example of an antenna member according to the present invention will be explained as an example. The content of the explanation is regarded as an antenna member according to the present invention including the IC card.
FIG. 3
schematically shows a state in which a plurality of IC cards
4
and
9
are piled up on a reader/writer
5
in a suitable direction for use.
While in the aforementioned explanation, a description has been made in which a plurality of IC cards are merely piled up for use, it includes (1) the case where a plurality of antenna members are used being piled up, and (2) the case where a plurality of IC cards are piled up without being intended for use. In the case of (1), there are many cases where the same kind of IC cards are used. On the other hand, in the case of (2), often, there are many cases where a different kind of IC cards are not discriminated, but for example, they are inserted into a pass case altogether and are used together with other IC cards for different purposes.
Regarding the way of piling up IC cards, it is generally assumed that they are piled up almost along the contour of the IC card. Examples contemplated include (1) the way of piling up a card by turning it over in a vertical direction (to top and bottom) and lateral direction (to left and right) with respect to a single card, (2) the way of piling up a card by turning it over in a lateral direction relative to a single card, and (3) the way of piling up a card with (1) and (2) compounded. In the case of piling up a plurality (three or more) of cards, a plurality of these ways of piling up are present. Further, there is a case where while one card is in use, the other card is inserted. In this case, the way of piling up changes with time.
A problem will be described hereinafter in the case where a plurality of IC cards are piled up. In the case where a plurality of IC cards are piled up, a plurality of antenna coils of each IC card influence on one another so that capacity and inductance of the antenna coils of each IC card equivalently increase along therewith. That is, this state is that a different antenna coil is arranged parallel to one antenna coil. Therefore, a resonant frequency of the antenna coils of an IC card is deviated to a lower frequency than that of the case where a card is independently used. The deviation of the resonant frequency leads to such a state in which a signal voltage V
2
obtained from a signal taken in the IC card considerably lowers, and as a result, a circuit for processing a signal of the IC card become inoperative.
Detailed description of occurrence of a deviation in resonant frequency by a plurality of antenna coils mentioned above will be made later.
The summary of a basic idea of the present invention will be explained, and then various concrete forms of the invention disclosed in the present specification will be explained.
The present invention relates to a shape of an antenna in which when a plurality of IC cards are pilled up for use, even if the IC cards are piled up in any direction, receiving power of the IC cards is not greatly lowered and a normal using condition is secured.
An antenna is a device for radiating or receiving an electromagnetic wave, and for an IC card, in the form of a coil is normally often used. Many of such antenna coils are formed on a fixed IC card substrate. The simplest forming method is to print a conductor for an antenna on an IC card substrate into a desired shape, which is also inexpensive to implement. Or there are methods in which a conductor layer for an antenna is formed on an IC card substrate, followed by etching into a desired shape, and a method in which a conductor for an antenna is formed separately from an IC card substrate to mount it on the substrate later. It is noted that physical or electric specifications such as a thickness, an electric conductivity or the like of an antenna conductor may be applied with the related art ones. As for various techniques other than the antenna shape, such as a tuning cir
Andou Kimiaki
Date Shigeru
Dobashi Hisanobu
Kanno Shin
Ookawa Takehiro
Hitachi , Ltd.
Mattingly Stanger & Malur, P.C.
Pitts Harold I.
LandOfFree
IC card does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with IC card, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and IC card will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2454994