Plural-coil non-contact IC card having pot cores and shielding walls

• US 5,198,647 A
• Filed: 11/27/1990
• Issued: 03/30/1993
• Est. Priority Date: 11/28/1989
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Mizuta, Masaharu
• Primary Examiner(s): Shepperd, John W.
• Assistant Examiner(s): Sikorski, Edward
• Application Number:
  US07/618,402
• Time in Patent Office: 854 Days
• Field of Search: 235/493, 235/492, 235/449, 235/382, 340/825.54, 340/825.31, 336/83, 336/84 R, 336/84 C, 336/90, 336/96, 336/205
• US Class Current: 235/449
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies
• CPC Class Codes: G06K 19/07779 the inductive antenna being a coil
• CPC Class Codes: G06K 19/07781 the coil being fabricated in a winding process
• CPC Class Codes: G06K 19/07783 the coil being planar
• CPC Class Codes: G06K 19/07784 the inductive antenna consisting of a plurality of coils stacked on top of one another
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil

Abstract

In a non-contact IC card based on an electromagnetic induction system, N small thin-film coils formed by thin-film technology are arranged to perform N-bit parallel data transfer at an increased data transfer rate. Each thin-film coil may be constructed with a pot core to solve a problem relating to errors in positioning the card relative to a terminal unit and thereby improving the reliability of data transfer. Shielding walls may be provided between the adjacent thin-film coils to prevent interference therebetween. The N thin-film coils are integrally formed as a thin-film coil module.

Claims

1. A non-contact IC card for transmission and reception of a signal between the card and a terminal unit by electromagnetic induction comprising:

memory means for storing data;

first coil means for parallel transfer of N-bit data between the card and the terminal unit by electromagnetic induction, said first coil means including an insulating substrate, N thin-film coils disposed on said substrate, where N is an integer greater than one, a respective ferromagnetic pot core for each of said N thin-film coils, each of said N coils including at least one layer of a spiral electrically conductive thin-film pattern surrounded by the respective pot core, and electrically conducting shielding walls disposed on said substrate between adjacent coils and corresponding pot cores for magnetically shielding said thin-film coils from each other;

second coil means including a coil for receiving from the terminal unit an instruction signal for parallel reading and writing of data and a respective pot core, said coil of said second coil means including at least one layer of a spiral electrically conductive thin-film pattern surrounded by said pot core;

control means connected between said first and second coil means and said memory means to control reading and writing of the parallel data to said memory means in accordance with the instruction signal; and

power supply means for receiving electric power from outside of the card by electromagnetic induction.

2. A non-contact IC card according to claim 1 wherein the said thin-film coils of said first and second coil means are an integral module disposed on the insulating substrate, said module including a molded cover.

3. A non-contact IC card according to claim 2 wherein said pot core is selected from the group consisting of ferrite and permalloy and said molded cover is an electrically insulating material.

4. A non-contact IC card according to claim 1 wherein said memory means includes a non-volatile memory, and said power supply means includes a power coil for receiving power from the terminal unit by electromagnetic induction, a clock signal line for supplying a current induced in said power coil to said control means and said memory means as a clock signal, and a rectifier circuit for rectifying the induced current and supplying the rectified current to said memory means and said control means.

5. A non-contact IC card according to claim 1 wherein said memory means includes a volatile memory, and said power supply means includes a power coil for receiving power from the terminal unit by electromagnetic induction, a clock signal line for supplying a current induced in said power coil to said control means and said memory means as a clock signal, a rectifier circuit for rectifying the induced current and supplying rectified power to said memory means and said control means, an internal battery for backup of said memory means, and a circuit for selectively supplying the rectified power from said rectifier circuit and power from said internal battery to said memory means and said control means.

6. A non-contact IC card according to claim 1 wherein N=8 for 8-bit parallel data transfer between the card and the terminal.

7. A non-contact IC card system comprising:

a non-contact IC card according to claim 1; and

a terminal unit having third coil means positioned for facing said first coil means of said IC card, for transferring the N-bit parallel data signal, and including N thin-film coils, fourth coil means positioned for facing said second coil means and including a thin-film coil for transferring the instruction signal, and second power supply means for supplying power to said power supply means of said IC card by electromagnetic induction.