Smart Textiles – Adding Value to Sri Lankan Textiles The Electronic Textiles Option (Handout) By Tilak Dias School of Materials The University of Manchester, UK

1. Smart Textiles – Adding Value to Sri Lankan Textiles
The Electronic Textiles Option
Dr Tilak Dias
School of Materials
The University of Manchester, UK

2. Tilak Dias
Introduction
• 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

3. Tilak Dias
Introduction
Next generation of textiles will be active and
intelligent;
i.e. they would be able to adapt to changes in
the environment
Question
What are they ?

4. Tilak Dias
SMART & Intelligent Knitted Structures
Core Elements
Knitted transducers
Intelligent signal processing
Knitted actuators

5. Tilak Dias
Background

6. Tilak Dias
Background
Research team:
• Anura Fernando
• Edward Lay
• Kim Mitcham
• Ravindra Monaragala
• Ravindra Wijesiriwardana
• William Hurley

7. Tilak Dias
Research in Electro-textiles
• Heat generating knitted structures
• Knitted transducers and sensors
• Light emitting fabrics
• Electronically active yarns

8. Tilak Dias
Electrically Active Knitted Structures
Concept of creating textiles with significant electrical properties:
Incorporate conductive elements into the structure
knitted structure
Electro Conductive Area (ECA)

9. Tilak Dias
Science and Technology Base
Advantage of using knitted structures
•
•
•
•

10. Tilak Dias
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
Stainless steel yarn

11. Tilak Dias
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

12. Tilak Dias
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®

13. Tilak Dias
Scan2Knit Technology
Computerised flat-bed knitting technology to create
three dimensionally shaped seamless stockings
Stoll CMS 330.6, E18

14. Tilak Dias
Advantages of using modern computerised flat-
bed knitting technology to create medical textiles
• Precision positioning of fibers in 3D space
• Ability to create seamless 3D structures
• Multilayer structures
• True seamless garment knitting techniques
• “Scan2Knit” technology

15. Tilak Dias
Example of a knitted sensor
Conductive pathway 1
Base structure
ECA
Conductive pathway 2

16. Tilak Dias
Modelling
RH
RL RL
RH
Unit Cell - Stitch Electrical Equivalent Circuit

17. Tilak Dias
Modelling
Calculation of RH and RL
Lleg Lhead
RL  RH 
A A
RL Resistance of the stitch leg RH Resistance of the stitch head
Lleg Yarn length in the stitch leg Lhead Yarn length in the stitch head
A Yarn cross sectional area A Yarn cross sectional area
ρ Resistivity of yarn ρ Resistivity of yarn

18. Tilak Dias
Equivalent resistive mesh circuit of the ECA
Modelling 22
Equivalent Resistance (Req)
20
18
16
14
12
10
20
10 20
15
10
0 5
0
Relationship between equivalent
resistance and stitch density of the ECA
Dimensions of the ECA:
m courses x n wales Assumption: Lleg = 2 Lhead

19. Tilak Dias
Theoretical Prediction of Current Distribution
Current Distribution in Stitch Heads Temperature Distribution in Stitch Heads
Current Distribution in Stitch Legs Temperature Distribution in Stitch Legs

20. Tilak Dias
Heating Glove
Conductive pathways
ThermoKnit® heater
elements (ECA)
Power Vs Temperature (Room temp: 25°C ) Voltage Vs Average Steady State Temperature (Room temp: 25°C)

21. Tilak Dias
Knitted Switch Technology “K-Switch”
Motivation:
Development of Next Generation of Textiles for the Automotive
Industry
Industry Requirement:
• Textile based switches and sensors with electro conductive
pathways
• Heating textiles
• Light emitting textiles (headliners)

22. Tilak Dias
Knitted structure with 4 dual ECAs (K-Switches)
ECA2
ECA1
Knitted structure 20m
m
Constructional information:
Principle of operation:
The minimum gap between the ECAs:
Measurement of DC resistance between • Yarn filament diameter;
the two ECAs • Stitch length

23. Tilak Dias
K-Switch Technology
DC Resistance variation
Operation of the K-Switch
Principle of operation:
Measurement of the DC resistance
between the two ECAs
Determined with a precision digital multimeter
under two wire resistance measurement
configuration at 0.1s sample rate

24. Tilak Dias
K-Switch Technology
DC Resistance variation with time
Observation: less than 300µs settling time

25. Tilak Dias
Applications K-Switch Technology

26. Tilak Dias
K-Switch Technology
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
Limitations:
• Simple electronics
• Switch characteristics depends on skin resistance
• Ineffective to other materials

27. Tilak Dias
K-Switch Technology
Modelling of Impedance between the ECAs
Cole-Cole model equivalent circuit of the
ECA - Skin - ECA Impedance

28. Tilak Dias
Influence of the measurement frequency on the
impedance - open circuit of the ECAs
Open circuit impedance is 0.1954 MΩ
at frequencies greater than 2 MHz
Impedance in MΩ
K-Switch Technology
Frequency in MHz

29. Tilak Dias
Impedance characteristics of K-Switch
Closed circuit of the ECAs
K-Switch Technology

30. Tilak Dias
Impedance characteristics of K-Switch
Closed circuit of the ECAs
K-Switch Technology

31. Tilak Dias
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 sheets
Screen printing micro-encapsulated phosphors (Osram) on to
plastic sheets
EL layer (µm) Conductive transparent layer (µm)
2 dielectric layers (µm)
Silver layer (µm)
Plastic sheet (base)

32. Tilak Dias
EL Yarn Technology
Motivation:
Develop EL Yarns which could be integrated into textile structures
Concept
1. Electro-conductive yarn
2. Dielectric layer
3. EL layer
4. Transparent protective
layer
5. Conductive wire

33. Tilak Dias
Experimental Rig

34. Tilak Dias
Not activated Activated – low frequency
Knitted EL Samples
Activated – high frequency

35. Tilak Dias
Application of EL Fibres
• 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

36. Tilak Dias
Garment System for vital sign monitoring
Background
Suggestion from School of Medicine, University of Manchester
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
Initial funding from The Department of Trade and Industry, UK
Setting-up research team for Science & Technology
development

37. Tilak Dias
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)

38. Tilak Dias
Commercialisation of Technology
• IPR protected by UMIP
1 core patent
• IPR assigned to a group of entrepreneurs
• Formation of a joint venture company by UMIP
SmartLife® Technology Ltd
• 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

39. Tilak Dias
SmartLife® Health Vest
2004
2004 2007

40. Tilak Dias
Signal comparison
Signal from standard Ag/AgCl Gel electrodes Signal from SmartLife® electrodes
Amplitude (mV) Duration (ms)
Signal
Section 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

41. Tilak Dias
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)

42. Tilak Dias
Current Research
Sensor sock for drop
foot detection
High frequency textile
antenna

43. Tilak Dias
Future …… Electronically functional yarns
Fibres and yarns with
sensors, transducers
and activators

44. Tilak Dias
Apparel Manufacturing Process Interface
Key process steps Integration of electronic devices with apparels
Active and sensory micro-devices
GARMENT
Fibres/Yarn Fabric Garment
Manufacture Manufacture
2nd Generation Manufacture
3rd Generation
1st Generation
1st Generation

45. Tilak Dias
Electronically active and sensor fibres
Technology is based on the encapsulated area not
exceeding 110% of the thread thickness

46. Tilak Dias
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

47. Tilak Dias
Micro-device Encapsulation Technology
Involves encapsulating devices with a flexible hermetic
seal for mechanical, thermal and electrical protection

48. Tilak Dias
MET Platform
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

49. Tilak Dias
MET Platform

50. Tilak Dias
INVENTION
Micro-device
Encapsulation
Technology Platform
Prototype
Demonstrator ?

51. Tilak Dias
Demonstrator 1 Light Emitting Fibres
Yarn with a working Diode Energised
(0.4 x 1.0 x 0.3 mm LED)

52. Tilak Dias
Light Emitting Garments
Events Garments

53. Tilak Dias
Demonstrator 2 RFID Fibres
Aim: Development of MET for embedding Hitachi MU Tag
© Copyright EntellFibres Ltd 2008

54. Tilak Dias
Current Research
Development of light emitting fabrics
• Active fashion garments
• Displays
Development of sensory yarn capable of:
• Monitoring strain/stress
• Sensing temperature
• Pressure measurement
• Sensing fluids/liquids

55. Thank You