Download - Smart Textiles – Adding Value to Sri Lankan Textiles The Electronic Textiles Option (Handout)
Smart Textiles – Adding Value to Sri Lankan TextilesThe Electronic Textiles Option
Dr Tilak DiasSchool of MaterialsThe University of Manchester, UK
Tilak Dias
• All current commodity textiles are passive;
i.e. not capable of adapting to environmental
changes
• Current technical textiles are engineered to
perform within a defined set of parameters; may
have the ability to adapt to changes within very
narrow bandwidth of environmental changes
Introduction
Question
What are they ?
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Next generation of textiles will be active and
intelligent;
i.e. they would be able to adapt to changes in
the environment
Introduction
SMART & Intelligent Knitted Structures
Core Elements
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Knitted transducers
Intelligent signal processing
Knitted actuators
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Background
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Background
Research team:
• Anura Fernando
• Edward Lay
• Kim Mitcham
• Ravindra Monaragala
• Ravindra Wijesiriwardana
• William Hurley
Research in Electro-textiles
• Heat generating knitted structures
• Knitted transducers and sensors
• Light emitting fabrics
• Electronically active yarns
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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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Advantage of using knitted structures
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Science and Technology Base
Use of electro-conductive fibres/yarns
Metal yarns (mono-filament and multi-filament)
Metal deposition yarns
Carbon fibres and yarns
Conducting polymeric yarns
Stainless steel yarn
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Creation of ECA
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
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Creation of ECA
Use of electro-conductive fibres/yarns
Metal yarns (mono-filament and multi-filament)
Metal deposition yarns
Carbon fibres and yarns
Conducting polymeric yarns
Silicone monofilament yarn loaded with Carbon (0.5mm diameter); FabRoc®
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Creation of ECA
Computerised flat-bed knitting technology to create
three dimensionally shaped seamless stockings
Stoll CMS 330.6, E18
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Scan2Knit Technology
• Precision positioning of fibers in 3D space
• Ability to create seamless 3D structures
• Multilayer structures
• True seamless garment knitting techniques
• “Scan2Knit” technology
Advantages of using modern computerised flat-
bed knitting technology to create medical textiles
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Base structure
ECA
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Conductive pathway 2
Example of a knitted sensorConductive pathway 1
Unit Cell - Stitch Electrical Equivalent Circuit
RH
RH
RLRL
Modelling
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Calculation of RH and RL
A
LR
leg
L
RL Resistance of the stitch leg
Lleg Yarn length in the stitch leg
A Yarn cross sectional area
ρ Resistivity of yarn
A
LR head
H
RH Resistance of the stitch head
Lhead Yarn length in the stitch head
A Yarn cross sectional area
ρ Resistivity of yarn
Modelling
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Equivalent resistive mesh circuit of the ECA
Dimensions of the ECA: m courses x n wales
Modelling
Relationship between equivalent resistance and stitch density of the ECA
Assumption: Lleg = 2 Lhead
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Equ
ival
en
t R
esi
stan
ce (
Req
)
Current Distribution in Stitch Heads
Current Distribution in Stitch Legs
Temperature Distribution in Stitch Heads
Temperature Distribution in Stitch Legs
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Theoretical Prediction of Current Distribution
ThermoKnit® heater elements (ECA)
Power Vs Temperature (Room temp: 25°C ) Voltage Vs Average Steady State Temperature (Room temp: 25°C)
Heating Glove
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Conductive pathways
Motivation:Development of Next Generation of Textiles for the Automotive Industry
Knitted Switch Technology “K-Switch”
• Heating textiles
Industry Requirement:
• Textile based switches and sensors with electro conductive pathways
• Light emitting textiles (headliners)
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Knitted structure with 4 dual ECAs (K-Switches)
Knitted structure 20mm
ECA2
ECA1
Constructional information: The minimum gap between the ECAs:• Yarn filament diameter;• Stitch length
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Principle of operation:
Measurement of DC resistance between
the two ECAs
K-Switch Technology
DC Resistance variation
Determined with a precision digital multimeter under two wire resistance measurement configuration at 0.1s sample rate
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Operation of the K-Switch
Principle of operation:Measurement of the DC resistance between the two ECAs
K-Switch Technology
DC Resistance variation with time
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Observation: less than 300µs settling time
K-Switch Technology Applications
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Analysis
Advantages:
• Easy and reliable manufacture
• Higher degree of design capability (3 yarn jacquard knitting)
• Cost effective manufacture
• Higher durability and life time
• Straightforward integration of K-Switches for different applications
K-Switch Technology
Limitations:
• Simple electronics
• Switch characteristics depends on skin resistance
• Ineffective to other materials
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Modelling of Impedance between the ECAs
K-Switch Technology
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Cole-Cole model equivalent circuit of the ECA - Skin - ECA Impedance
K-S
wit
ch T
ech
no
logy
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Imp
ed
ance
in M
Ω
Frequency in MHz
Open circuit impedance is 0.1954 MΩ at frequencies greater than 2 MHz
Influence of the measurement frequency on the impedance - open circuit of the ECAs
K-S
wit
ch T
ech
no
logy
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Impedance characteristics of K-Switch Closed circuit of the ECAs
K-S
wit
ch T
ech
no
logy
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Impedance characteristics of K-Switch Closed circuit of the ECAs
Electro-Luminescent Fibre Structures
Theoretical background:Exposure of an electroluminescent substance to a high frequency electrical field radiate light
The state-of-the-art
EL polymer sheetsScreen printing micro-encapsulated phosphors (Osram) on to plastic sheets
Plastic sheet (base)
Silver layer (µm)
2 dielectric layers (µm)
EL layer (µm) Conductive transparent layer (µm)
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EL Yarn Technology
Motivation:
Develop EL Yarns which could be integrated into textile structures
1. Electro-conductive yarn2. Dielectric layer3. EL layer4. Transparent protective
layer5. Conductive wire
Concept
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Experimental Rig
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Knitted EL Samples
Activated – low frequency
Activated – high frequency
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Not activated
Application of EL Fibres
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• Light Emitting Textiles
• Transport sector, passenger cabin design of vehicles; e.g. headliners, carpets, upholstery
• Advertising industry; e.g. flexible and drapable billboards and notice boards
• Buildings; e.g. ceilings, walls, carpets
• Household products; e.g. curtains, furniture fabrics, wall hangings, lamp shades, decorative products
• Safety and security products
• Light Emitting Braids and Ropes• Safety and security products• Decorative and fashion products
Suggestion from School of Medicine, University of Manchester
Background
Initiation of partnership between Imaging Science and Biomedical Engineering (ISBE), Medical School; Digital Signal Processing Group (DSPG), School of Electrical & Electronics, and Department of Textiles (UMIST) in 2002
Setting-up research team for Science & Technology development
Initial funding from The Department of Trade and Industry, UK
Garment System for vital sign monitoring
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Research Achievements
• Creation of Science base for knitted transducers• Knitted dry electrodes• Knitted strain gauges• Knitted inductive sensors • Knitted conductive pathways
• Development of technology for producing a garment with integrally knitted sensors and conductive pathways
• Development of vest with 2 lead ECG (proof of concept)
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Commercialisation of Technology
• Raised funds by SmartLife® for development of core technology in the University (SoM, ISBE, DSPG)
• Development of “Health Vest” with 3 leads ECG, Respiratory and Skin Temperature monitoring
• Development of hardware and signal processing software
• IPR protected by UMIP1 core patent
• IPR assigned to a group of entrepreneurs
• Formation of a joint venture company by UMIPSmartLife® Technology Ltd
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2004 2007
20
04
SmartLife® Health Vest
Signal comparison
Signal from standard Ag/AgCl Gel electrodes Signal from SmartLife® electrodes
Signal Section
Amplitude (mV) Duration (ms)
Ag/AgCl Vest Ag/AgCl Vest
P wave 0.2 0.3 120 120
QRS complex 2.0 2.5 80 80
T wave 0.5 0.5 240 240
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Target Markets
1. Health, Wellbeing & Homecare Market size e.g. cardiovascular: ECG US$8bn1
Predictive monitoring
Clinical monitoring of patients in their own homes
2. Sports Estimated market size US$2bn – Professional Personal monitoring Training, lifestyle, personal
3. Hazardous Environment – first responders, military Estimated market size US$2bn
[1] Global Market For Patient Monitoring devices US$11.4bn (Frost & Sullivan 2005)
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Current Research
Sensor sock for drop foot detection
High frequency textile antenna
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Electronically functional yarns
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Future ……
Fibres and yarns with
sensors, transducers
and activators
Fibres/Yarn Manufacture
Fabric Manufacture
Garment Manufacture
GA
RM
ENT
Key process steps Integration of electronic devices with apparels
1st
Ge
ne
rati
on
1st
Ge
ne
rati
on
2n
dG
en
era
tio
n
3rd
Ge
ne
rati
on
Apparel Manufacturing Process Interface
Active and sensory micro-devices
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Technology is based on the encapsulated area not exceeding 110% of the thread thickness
Electronically active and sensor fibres
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Vision
The development of novel technology for
fabricating electronically active and sensor
fibres which will be the basic building blocks of
the next generation ‘SMART’ fibrous materials
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Micro-device Encapsulation Technology
Involves encapsulating devices with a flexible hermetic seal for mechanical, thermal and electrical protection
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μ-devices:
• electronic chips
• magnetic devices
• optical devices
• thermal devices
Schematic diagram of a yarn device
• Development of the concept of encapsulating
• Mathematical modelling
• Design and development of an experimental rig
• Demonstrator E-Yarn with a working diode (LED) and RFID tag
MET Platform
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MET Platform
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INVENTION
Micro-device Encapsulation Technology Platform
Prototype Demonstrator ?
Yarn with a working Diode (0.4 x 1.0 x 0.3 mm LED)
Light Emitting Fibres
Energised
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Demonstrator 1
Light Emitting Garments
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Events Garments
RFID Fibres
Aim: Development of MET for embedding Hitachi MU Tag
Demonstrator 2
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Development of sensory yarn capable of:
• Monitoring strain/stress
• Sensing temperature
• Pressure measurement
• Sensing fluids/liquids
Current Research
Development of light emitting fabrics
• Active fashion garments
• Displays
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Thank You