Registers – Records – Conductive
Reexamination Certificate
1998-05-15
2001-01-23
Frech, Karl D. (Department: 2876)
Registers
Records
Conductive
C235S380000
Reexamination Certificate
active
06176433
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a reader and/or writer for performing transmission of proximity radio operating power to and communications with proximity radio cards such as a cash card, a credit card, a railway ticket, a commutation ticket, a coupon ticket, a management card, an ID card, a license, etc. employed in, for example, a cash dispenser, electronic money, an automatic checking and collecting system, a room in/out management system, etc.
It has heretofore been known in Japanese Patent Application Laid-Open Nos. Hei 7-85233 and 9-62816 that power is supplied to a proximity radio card (IC card) from the power supply side in a noncontact manner with the card by using light or magnetic fields.
In a noncontact card system (proximity radio card system) wherein when cash cards, credit cards, railway tickets, commutation tickets, etc. to be used at wickets in railway stations or on buses or at entrances and exits or the like are brought into IC cards, and when a user causes his/her IC card to pass through a reader and/or writer provided at a wicket in a railway station or on a bus or at an entrance and exit or the like in a noncontact manner with the reader and/or writer, a power transmitting wave or a communication wave is radiated from a coil or an antenna of the reader and/or writer and the electromagnetic wave is received by and thereby a voltage is induced by a coil or an antenna provided on the card side to thereby operate circuits on the card side, whereby a signal is detected, the electric field radiated from the coil or antenna of the reader and/or writer needs to satisfy the restricted value (500 &mgr;V/m at a distance of 3 m) of the Wireless Telegraphy Act.
However, a problem arises in that since the upper limit of the value of a current flowing through the coil or antenna for the reader and/or writer is determined under the restricted value (500 &mgr;V/m at the distance of 3 m) of the radiated electric field according to the Wireless Telegraphy Act and the upper limit of the intensity of a magnetic field necessary for power transmission and communications is determined according to the upper limit of the current value, a communicable range is restricted.
Japanese Patent Application Laid-open No. Hei 9-212606 as a prior art discloses a noncontact reader and/or writer having three or more loop coils wherein carrier signals, which are different in phase to each other, are applied at a predetermined frequency across each of the plurality of loop coils with a phase shifter to cancel electromagnetic fields at a distant so that effect upon radiation to peripheral devices is suppressed. In such a prior art, however, a waveform on which magnetic fields generated from each coil are overlapped is supplied to a card. As a result, the overlapped wavefom has a waveform width wider than that of a desired waveform, resulting in deformation. Thus, it is impossible to transmit correct information.
SUMMARY OF THE INVENTION
With the foregoing problems in view, it is therefore an object of the present invention to provide a reader and/or writer suitable for use in a proximity radio card system, which is capable of satisfying the restricted value (500 &mgr;V/m at a distance of 3 m) of a radiated field according to the Wireless Telegraphy Act, and enlarging a communicable range, i.e., a communicable distance between the reader and/or writer and a proximity radio card (IC card) to establish good communications.
According to one aspect of this invention, for achieving the above object,'there is provided a reader and/or writer having a main coil or a spiral antenna for generating an electromagnetic field for performing both the supply of operating power to an IC card and transmission of a communication signal to the IC card or transmission and reception thereof to and from the IC card.
According to another aspect of this invention, for achieving the above object, there is provided a reader and/or writer for performing both the supply of operating power to an IC card and transmission of a communication signal to the IC card or transmission and reception thereof to and from the IC card, which comprises an antenna wherein a plurality of coils or spiral antennas are caused to distribute currents lying in the same direction and opposite in phase or lying in the opposite direction and being in phase to thereby generate magnetic fields serving as components opposite in phase to each other and the directivities thereof are synthesized, whereby power transmission and satisfactory communications are allowed in mutually interference-free very near areas and the magnetic fields interfere with each other and cancel out each other in the distance so that the radiated electric field is restrained. Owing to the above construction, a communicable range can be greatly enlarged or controlled while obeying the Wireless Telegraphy Act.
According to a further aspect of this invention, for achieving the above object, there is provided a reader and/or writer for performing the supply of operating power to an IC card and transmission or transmission and reception of a communication signal to and from the IC card, comprising a main coil or a spiral antenna for generating an electromagnetic field used for the two or power supply, and auxiliary coils or spiral antennas for generating magnetic fields opposite in phase to the electromagnetic field generated by the main coil or spiral antenna to thereby control or restrain the intensity of the electromagnetic field in the distance.
According to a still further aspect of this invention, for achieving the above object, there is provided a reader and/or writer for performing both the supply of operating power to an IC card and transmission of a communication signal to the IC card or transmission and reception thereof to and from the IC card, comprising a main coil or a spiral antenna for generating an electromagnetic field used for the two or power supply, and auxiliary coils or spiral antennas for generating axial magnetic fields opposite in direction to the electromagnetic field generated by the main coil or spiral antenna to thereby restrain the intensity of the electromagnetic field in the distance.
In the reader and/or writer according to the present invention, the main coil or spiral antenna and the auxiliary coils or spiral antennas are respectively supplied with power so as to differ in phase from each other.
Further, in the reader and/or writer according to the present invention, the main coil or spiral antenna and the auxiliary coils or spiral antennas are constructed so as to differ in winding direction from each other.
Moreover, in the reader and/or writer according to the present invention, the main coil or spiral antenna and the auxiliary coils or spiral antennas are respectively supplied with power so as to differ in phase from each other as to a power transmitting wave and supplied with power in phase with each other as to a signal wave.
According to a still further aspect of this invention, for achieving the above object, there is provided a reader and/or writer for performing both the supply of operating power to an IC card and transmission of a communication signal to the IC card or transmission and reception thereof to and from the IC card, wherein a main coil or a spiral antenna for generating an electromagnetic field for the two or power supply and auxiliary coils or spiral antennas for restraining the intensity of the electromagnetic field in the distance generated by the main coil or spiral antenna are provided side by side.
According to a still further aspect of this invention, for achieving the above object, there is provided a reader and/or writer for performing both the supply of operating power to an IC card and transmission of a communication signal to the IC card or transmission and reception thereof to and from the IC card, wherein a main coil or a spiral antenna for generating an electromagnetic field used for the two or power supply and auxiliary coils or spiral antennas are provided side by side and an
Hayashi Yoshihiko
Makuuchi Masami
Suga Takashi
Uesaka Kouichi
Yoshino Ryozo
Antonelli Terry Stout & Kraus LLP
Frech Karl D.
Hitachi , Ltd.
LandOfFree
Reader/writer having coil arrangements to restrain... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reader/writer having coil arrangements to restrain..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reader/writer having coil arrangements to restrain... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2458137