Textiles with Electronic Functionality

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Professor Tilak Dias Advanced Textiles Research Group

School of Art and Design 07th March 2013

Smart & Interactive Textiles (SMIT)

• New emerging sector of textiles

• Market growth rate is forecasted at 40% annually and to reach US$2.5 billion by 2021

• Although still in its infancy, the US market for SMIT was $70.9 million in 2006, and $391.7 million in 2012

Smart and interactive textiles (SMIT) can sense electrical, thermal, chemical, magnetic or other stimuli in the environment and adapt or respond to them, using functionalities integrated into the textile’s structure.

(Foresight Horizon Scanning Centre, www.bis.gov.uk/foresight, URN: 10/1252 – Technology

and innovation futures)

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Introduction

• Good tensile recovery properties

• Superior conformability and excellent skin contact with knitted structures

• Breathability; the structures are air permeable hence better comfort

• Freedom of constructing structures with different pattern elements

Textile structures are created by binding fibres (physical binding)

Why use textiles to create interactive systems?

General properties of textiles (fibre structures)

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• Robust and easily programmable manufacturing systems

• High production speeds

• Large area structures

Key manufacturing features

Introduction

Capability of creating comfortable wearable electronics

• Efficient sensors (vital signs, posture) and actuators (interaction) on the body

• Ability for placing sensors and actuators accurately

• Uninterrupted monitoring

• Possibility of providing therapy during day to day activities

Advantages of using textiles to develop SMITs

Smart & Interactive Textiles

Capability of creating large-area electronic systems

• Sensor systems for ‘ambient intelligence’

• Lighting and heating/cooling systems

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SMART & Interactive Textiles

Core Elements

Transducers

Intelligent Signal Processing

Actuators

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Advantages of this technology

• Precision positioning of fibers in 3D space

• Ability to create seamless 3D structures

• Multilayer structures

• Ability to process different types of yarns

Computerised flat-bed knitting technology to create e-textiles

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Electrically Active Knitted Structures

Electro Conductive Area (ECA)

Concept of creating textiles with significant electrical properties: Incorporate conductive elements into the structure

Knitted structure

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Use of electro-conductive fibres/yarns

Metal yarns (mono-filament and multi-filament)

Metal deposition yarns

Carbon fibres and yarns

Conducting polymeric yarns

PA yarn vacuum coated with Ag nano layer

Creation of ECA

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Unit Cell - Stitch Electrical Equivalent Circuit

Modelling

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Equivalent resistive mesh circuit of the ECA

Dimensions of the ECA: m courses & n wales

Relationship between equivalent resistance and stitch density of ECA

Assumption: Lleg = 2 Lhead

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Garment for vital sign monitoring

Study of knitted electrodes - Objectives

• Quantify signal to noise ratio dependence on knitted electrode pressure

• Compare performance of a number of conductive yarns for electrode construction

• Determine the design for the ECG garment design

Garment for vital sign monitoring

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Standard Ag-AgCl Electrodes with conductive gel

Garment for vital sign monitoring ATRG_TD

Electrodes knitted with silver yarn (dry state)

Garment for vital sign monitoring ATRG_TD

Sensor sock for monitoring of 3D foot orientation

Knitted stocking with:

• Knitted resistive stretch (KRS) sensors

• Knitted conductive pathways

• Seamless knitted garment

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Sensor sock for monitoring of 3D foot orientation

Performance of the Sensor Sock

Sensor sock with kinematic markers used for trials Sensor output and scaled kinematic signal against time

for a single walking trial

Kinematic signal

KRS sensor output

Heel lift Toe off Heel strike

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Technology is based on the encapsulated area not exceeding 110% of the thread thickness

Electronically active fibres/yarns

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Vision

The development of the technology for fabricating

electronically active intelligent fibres/yarns which

will be the basic building blocks of the next

generation ‘Smart and Interactive Textiles (SMIT)’

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Involves encapsulating micro-devices with a flexible hermetic seal for mechanical, thermal and electrical protection

Electronically Active Fibre/Yarn Technology

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Sensor Fibres

• Strain measurement • Temperature measurement • Fluid/gas measurement • Radiation sensing • Light measurement • Acoustic measurement • Motion detection • Pressure measurement

• RFID • Light emitting • Vibration • Magnetic • Transmission • Peltiers

Active Fibres

Potential of the core technology

• Micro-controllers • Micro-processors

Intelligent Fibres

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Thank You

Contact details: Professor Tilak Dias Advanced Textiles Research Group Tel.: 0115 848 6518 Email: tilak.dias@ntu.ac.uk

Advanced Textiles Research Group School of Art and Design Nottingham Trent University Nottingham NG1 4BU http://twitter.com/#!/advancedtextile www.facebook.com/ntuadvancedtextiles www.ntuadvancedtextiles.wordpress.com

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Textiles with Electronic Functionality

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