Non-contact ic card

• US 20060118638A1
• Filed: 10/23/2003
• Published: 06/08/2006
• Est. Priority Date: 11/22/2002
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kawabe, Hideo, Ohsako, Junichi, Ueda, Mitsunori, Odake, Ryota
• Granted Patent: US 7,575,175 B2
• Time in Patent Office: Days
• US Class Current: 235/492
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07703 the interface being visual
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 3/3629 using liquid crystals having memory effects, e.g. ferroelectric liquid crystals

Abstract

In a contactless IC card (1), a rectification circuit (17) rectifies an electromagnetic wave received via an antenna (10) to provide a DC voltage, and an electric double-layer capacitor (18) quickly stores the power from the rectification circuit (17). The electric double-layer capacitor (18) supplies the electric power to circuits such as a modem (11), CPU (12), memory (13), controller IC (14), driver IC (15), etc. for operation, and rewrites information for display on a display device (16) using a cholesteric liquid crystal, ferroelectric liquid crystal or the like.

Claims

1. A contactless IC card that exchanges information with an external data processor in a non-contact manner by an electromagnetic wave, the device including:

a rectifying means for rectifying an electromagnetic wave sent from the data processor;

an electric double-layer capacitor for storing a rectified power supplied from the rectifying means;

a controlling means for controlling the information exchange with the data processor and the display of information received from the data processor; and

a displaying means having a storing function to hold the display even after power supply is stopped and which displays the information under the control of the controlling means,

the electric double-layer capacitor being designed to store, for a shorter time than a time required for writing information, a sufficient power for supply to each component of the contactless IC card until the information is completely written to the displaying means under the control of the controlling means.

2. The device according to claim 1, wherein the displaying means is a liquid crystal display means having at least two stable states of alignment of liquid crystal molecules thereof and takes one of at least the two stable states of alignment of the liquid crystal molecules to display the information.

3. The device according to claim 2, wherein the liquid crystal is a ferroelectric or cholesteric one.

4. The device according to claim 1, further comprising:

a storage means for storing information received from the data processor; and

an information selecting means for selecting one to be displayed on the displaying means from the information stored in the storage means.

5. The device according to claim 1, wherein the electric double-layer capacitor is designed to store, in a time of 0.165 sec or less, a sufficient power for supply to each component of the contactless IC card until the information is completely written.

6. The device according to claim 1, having a thickness of 0.9 mm or less.