Reader/writer for use with non-contact IC card and reader/writer system

• US 5,821,525 A
• Filed: 08/02/1995
• Issued: 10/13/1998
• Est. Priority Date: 08/03/1994
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation), Mitsubishi Electric Semiconductor Software Company Limited
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation), Mitsubishi Electric Semiconductor Software Company Limited
• Inventors: Takebayashi, Etsushi
• Primary Examiner(s): Hajec, Donald T.
• Assistant Examiner(s): Le, Thien Minh
• Application Number:
  US08/510,411
• Time in Patent Office: 1,168 Days
• Field of Search: 235/375, 235/491, 235/492, 235/493, 343/742, 343/867, 343/895, 340/572
• US Class Current: 235/492
• CPC Class Codes: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles

Abstract

A non-contact IC card reader/writer which offers an improved reliability in communication between a non-contact IC card and its reader/writer by reducing malfunction due to data communication error. The reader/writer includes a reader/writer main body electrically connected to a host machine for controlling communications, and an antenna external to and electrically connected to the reader/writer main body for transmitting and receiving electromagnetic waves to and from the non-contact IC card. Since the antenna is L-shaped in cross section, the non-contact IC card is free from right-angle antenna geometry to the antenna and maintains a good communications link with the reader/writer.

Claims

1. A non-contact IC card reader/writer system comprising:

a reader/writer main body electrically connected to a host machine for controlling data communication;

antenna means disposed externally to and electrically connected to said reader/writer main body for transmitting and receiving electromagnetic waves to and from the non-contact IC card in a wireless manner, said antenna means having a board with a plurality of plane portions, the plane portions being arranged at an angle to each other, and a conductor wire being wound in a coil about each of the plurality of plane portions;

input/output means electrically connected to the host machine for inputting and outputting a bidirectional signal to and from the host machine;

transmitter-receiver means for modulating and demodulating electromagnetic waves including trigger signals and data signals transmitted and received by said antenna means;

control means electrically connected between said input/output means and said transmitter-receiver means for controlling the data communication; and

bi-signal level switching means for switching the strength of the output electromagnetic waves emitted by said antenna means between a first level for the trigger signal and a second level for the data signal.

2. The non-contact IC card reader/writer systems as claimed in claim 1, wherein said plurality of plane portions of said board of said antenna means are connected integrally to each other at a side and a conductor wire is wound in a coil along said plane portions.

6. The non-contact IC card reader/writer systems as claimed in claim 1, comprising a plurality of said antenna means.

7. The non-contact IC card reader/writer systems as claimed in claims 1, wherein the reader/writer main body includes a plurality of connection means for being selectively and electrically connected to said antenna means.

8. A non-contact IC card reader/writer system as claimed in claim 1 further comprising a repeater including

an antenna circuit remotely disposed between said antenna means of said non-contact IC card reader/writer and said non-contact IC card, for performing transmission and reception of electromagnetic waves between said non-contact IC card reader/writer and said non-contact IC card,

control means for controlling transmission and reception of the electromagnetic waves,

memory means for temporarily storing the demodulated signals,

modulator means for modulating the temporarily stored signals;

and

input/output control means electrically connected to said demodulator means and said modulator means for controlling input and output of signals.

10. The non-contact IC card reader/writer system as claimed in claim 1 wherein said bi-signal level switching means includes:

a data status signal circuit that generates a signal responsive to the data signal;

an amplifier for amplifying transmission signals, said amplifier including output resistors; and

a switch coupled to said data status circuit and to said amplifier to switch the output resistors in response to the signal generated by said data status circuit to said amplifier.

3. A non-contact IC card reader/writer system comprising:

a reader/writer main body electrically connected to a host machine for controlling data communication;

antenna means disposed externally to and electrically connected to said reader/writer main body for transmitting and receiving electromagnetic waves to and from a non-contact IC card in a wireless manner, said antenna means having a board with a plurality of plane portions, said plurality of plane portions being arranged at an angle to and separated from each other, wherein a conductor wire is wound in a coil about each of the plurality of plane portions;

input/output means electrically connected to the host machine for inputting and outputting a bi-directional signal to and from the host machine; and

transmitter/receiver means for modulating and demodulating electromagnetic waves transmitted and received by the antenna means; and

antenna control means for switching between conductor wires on said plurality of plane portions at predetermined intervals, wherein said antenna control means monitors a time period between completion of transmission of one of the electromagnetic waves transmitted by said antenna means and reception of a response to the electromagnetic waves transmitted by said antenna means and wherein said antenna control means switches from a first conductor wire on one of the plurality of plane portions to a second conductor wire on another of the plurality of plane portions when the time period monitored by said antenna control means is greater than a predetermined time period.

9. The non-contact IC card reader/writer as claimed in claim 3 wherein said antenna control means switches conductor wires from one of the plurality of plane portions to another one of the plurality of plane portions responsive to the electromagnetic waves transmitted by said transmitter/receiver.

4. A non-contact IC card reader/writer system comprising:

a reader/writer main body electrically connected to a host machine for controlling data communication;

antenna means disposed externally to and electrically connected to said reader/writer main body for transmitting and receiving electromagnetic waves to and from the non-contact IC card in a wireless manner, said antenna means having a board with a plurality of plane portions, the plane portions being arranged at an angle to each other, and a conductor wire being wound about the plurality of plane portions in a coil;

input/output means electrically connected to the host machine for inputting and outputting a bidirectional signal to and from the host machine;

transmitter-receiver means for modulating and demodulating electromagnetic waves including data signals, the electromagnetic waves being transmitted and received by said antenna means;

control means electrically connected between said input/output means and said transmitter-receiver means for controlling the data communication; and

bi-time level switching means for switching the strength of the output electromagnetic waves after each data signal transmission cycle to transmit a signal of the same content at a plurality of transmission signal strengths.

5. The non-contact IC card reader/writer system as claimed in claim 4, further comprising bi-signal level switching means for switching the strength of the output electromagnetic waves emitted by said antenna means between a first level for a trigger signal and a second level for a data signal.