GB2492944A

GB2492944A - A wearable contactless radio frequency identification (RFID) tag

Info

Publication number: GB2492944A
Application number: GB1110584.8A
Authority: GB
Inventors: Benjamin Nicholas Parton
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-06-22
Filing date: 2011-06-22
Publication date: 2013-01-23
Also published as: GB201110584D0

Abstract

A passive contactless RFID device comprises: an antenna for receiving a radio frequency signal from a reader and for transmitting a radio frequency signal to a reader; an integrated circuit (IC) or chip connected to the antenna for storing identification data and for processing and sending signals to the antenna; wherein the antenna is a helically-wound wire coil having multiple turns. The antenna is a compact coil which is sufficiently small to allow the device to be incorporated into wearable objects such as a watch wrist-strap or a finger ring. Uses of the device include as an entry tag, swipe-card, travel card, payment card or identification means.

Description

INTELLECTUAL

. . PROPERTY OFFICE Application No. GBI 110584.8 RTINI Dale:23 September 2011 The following terms are registered trademarks and should be read as such wherever they occur in this document: MIFARE. DESFire Intellectual Property Office is an operaling name of Ihe Patent Office www.ipo.gov.uk A wearable passive Contactiess Radio Frequency Identification (REID) Tae Technical Back2round The present invention provides a new design for a compact coil (Fig. 1 & 2) for use with certain types of existing High-Fmquency contactless Radio Frequency Identification (RFID) entry tag/swipe-card/travel card/paymenthdentification systems and infrastructures.

-Where the RFJD tag cannot have it's own power source (totally passive) and has to be used in close proximity to the reader (approx 10cm or less, usually 1-6cm) in order to work effectively because the signal strength generated by the reader/base station/touch-point/door entry point, must be restricted to minimise the possibility of interference with other Near Field Communication (NEC) devices, and where data security/privacy is a concern.

Disclosure of the Invention

The present invention is as defined in the accompanying claims.

The coil is designed to work with existing passive chip designs that operate with a Baudrate (Kbits/s) 106-848 at 13.56 MFli where the coil alone provides the required power to the chip and doubles as an antenna to communicate with the reader. e.g. those that adhere to the ISO/IEC 14443 Type A contactle.ss smart card standard, without the need to adjust or upgrade the reader.

The layout of the passive tag coil designs (fig. l& 2) are determined by the lack of an integrated battery in the tag and therefore the operational current required by the RFID chip (fig. 1,3) and by the signal strength and frequency being used/generated by the reader.

The new type of coil design (fig. I & 2) uses a unique layout (fig. I,l & 2,1) to reduce the cross-sectional area of the coil (fig. 1,2) and consequently the size of the whole tag without hindering it's ability to be powered by, or communicate with, the reader.

This in turn allows for a variety of new compact exterior forms (the overall shape of the body of material protecting the coil and chip). including smaller, more convenient, wearable tags. For example rings you can wear on your finger (fig. 3-7) and Watch widgets that can be retrofitted to any watchst rap without getting in the way or hindering the genera] use of the watch (Figs. 8-12).

The coil is made of length of enamelled copper wire 11 24mrn±Smrn (fig, 1,1) wound helically! vertically a specific number of turns (fig. 2,1), that are capable of being ananged parallel to the surface of the reader or touch-in' point (fig. 13 & 14). This is in contrast to the spirally-wound anangement of coils used in existing entry-card' or travel-card' tags.

Depending the final exterior shape of the tag required, the coil can he wound into different shapes e.g. square, circle, triangle or rectangular format (as long as they have a circumference or perimeter of 64mm±2mmm. Each turn in the coil butts up to the last without a gap (fig. 2). The coils can be large enough to site a standard ISO/IEC 14443 Type A 13.56 MHz contactiess smart card chip at its centre (in this case a NXP MIFARE DESFire EVI chip) (fig. 1,3) The coil (fig. 13,2 & 14,2) can then be set in solid plastic (fig.13,1 & 14,1) for increased protection without hindering it's operational effectiveness, and when completely surrounded in plastic rather than laminated in a flat bendab]e form the components are is far less susceptible to damage or malfunction from being over flexed. And once you are wearing it cannot be misplaced, forgotten and much less likely interferer with, react to or with any other NEC devises or tags you may be carrying.

In accordance with one embodiment, the invention provides a watchstrap widget (fig. 8- 12) consists of the aforementioned REID chip and coil (fig. 14.1) encased in silicone rubber that can be fitted to any watchstrap (fig. 34,2). The consistency of the rubber is firm enotgh to provide protection to the electronic components inside the main body of the widget while allowing the fastening strap to stretch and grip around the majority of watchstrap thicknesses and widths. It is thus held securely in place and is not susceptible to slipping.

Claims

<claim-text>Claims 1) A passive contactiess radio frequency identification (REID) tag tbr identifying the tag to a reader, which device comprises: an antenna for receiving a radio frequency signal from a reader and for transmitting a radio frequency signal to a reader; and an integrated circuit connected to the antenna for storing data identifying the tag and for processing signals received from the antenna and for sending signals to the antenna for transmission to a reader; wherein the antenna is a helically wound wire coil having multiple turns of a circumference of 64mm ± 12mm.</claim-text> <claim-text>2) A tag as claimed in claim I, wherein the antenna includes 16 to 20 turns, i.e. 16,17, 18, 19 or 20 turns, especially 18 turns.</claim-text> <claim-text>3) A tag as claimed in claim I or claim 2, wherein the wire in the antenna has a diameter of 0.1 to 0.2, e.g. about 0.15mm.</claim-text> <claim-text>4) A tag as claimed in any preceding claim, wherein the coil is a coil of insulated wire without gaps between the turns.</claim-text> <claim-text>5) A tag as claimed in any preceding claim, wherein the wire is insulated copper wire, especially enamel-coated copper wire.</claim-text> <claim-text>6) A tag as claimed in any preceding claim, wherein the helically wound wire coil has an axis that is perpendicular to the plane of each turn.</claim-text> <claim-text>7) A tag as claimed in any preceding claim, wherein the depth of the helically wound wire coil between the top thm and the bottom turn of the coil is 3.5 to 4mm, e.g. about 3.8mm.</claim-text> <claim-text>8) A tag as claimed in any preceding claim, wherein the helically wound wire coil is rectangular (including square), circular or triangular in cross-section taken perpendicular to the axis of the helix.</claim-text> <claim-text>9) A tag as claimed in claim 8, wherein the helically wound wire coil is rectangular, in cross-section and one side of the rectangle has a length of 18-22mm, e.g. 19- 21mm, for example 20±0.5 mm and the other side of the rectangle has a length of 10-14mm, e.g. 11-13mm, for example 12±0 5mm.</claim-text> <claim-text>10) A tag as claimed in any preceding claim, wherein the length of the wire in the coil is ll24rnm±lBmm.</claim-text> <claim-text>11) A tag as claimed in any preceding claim, wherein the integrated circuit operates at a baudrate of 106-848 Kbits/s at 13.56 MHz.</claim-text> <claim-text>12) A tag as claimed in any preceding claim, which is embedded in a rigid plastics material or iii a rubber material, e.g. silicone rubber.</claim-text> <claim-text>13) A band for encircling another object, especially for encircling a part of a person's hand, e.g. a finger, or wrist or for encircling an article worn on a person's hand or wrist e.g. a watchstrap. which band carries a tag as claimed in any preceding claim.</claim-text> <claim-text>14) A band as claimed in claim 13, which is a wrist strap or band.</claim-text> <claim-text>15) A band as claimed in claim 13, which is configured to be worn ainund a wrist strap, e.g. around a wristwatch strap.</claim-text> <claim-text>16) A band as claimed in any of claims 13 to 15, wherein pail of the band has a flat front face and the coil is embedded under the flat front face with each turn of the coil lying generally parallel to the front face.</claim-text> <claim-text>17) A band as claimed in claim 13, which is a finger ring.</claim-text> <claim-text>18) A band as claimed in claim 14, wherein the ring has a flat front face, e.g. in the manner of a signet ring, and the coil is embedded under the flat front face with each turn of the coil lying generally parallel to the front face.</claim-text> <claim-text>19) A band as claimed in any of claims 13-18, wherein the band is made of mouldable material, especially a stiff natural or artificial rubber, e.g. silicone rubber or a rigid plastic material.</claim-text>