Textiles with Electronic Functionality Professor Tilak Dias Advanced Textiles Research Group School of Art and Design 07 th March 2013
Smart & Interactive Textiles (SMIT) 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) New emerging sector of textiles Although still in its infancy, the US market for SMIT was $70.9 million in 2006, and $391.7 million in 2012 Market growth rate is forecasted at 40% annually and to reach US$2.5 billion by 2021
Why use textiles to create interactive systems? Textile structures are created by binding fibres (physical binding) General properties of textiles (fibre structures) 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 Key manufacturing features Robust and easily programmable manufacturing systems High production speeds Large area structures Introduction
Advantages of using textiles to develop SMITs 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 Capability of creating large-area electronic systems Sensor systems for ambient intelligence Lighting and heating/cooling systems Smart & Interactive Textiles Introduction
SMART & Interactive Textiles Core Elements Transducers Intelligent Signal Processing Actuators Introduction
Computerised flat-bed knitting technology to create e-textiles 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
Electrically Active Knitted Structures Concept of creating textiles with significant electrical properties: Incorporate conductive elements into the structure Electro Conductive Area (ECA) Knitted structure
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
Modelling R H R L R L R H Unit Cell - Stitch Electrical Equivalent Circuit
Equivalent resistance in KΩ Equivalent resistive mesh circuit of the ECA 22 20 18 16 14 12 20 10 10 0 0 5 10 15 20 Dimensions of the ECA: m courses & n wales Relationship between equivalent resistance and stitch density of ECA Assumption: L leg = 2 L head
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
Standard Ag-AgCl Electrodes with conductive gel Garment for vital sign monitoring
Electrodes knitted with silver yarn (dry state) Garment for vital sign monitoring
Sensor sock for monitoring of 3D foot orientation Knitted stocking with: Knitted resistive stretch (KRS) sensors Knitted conductive pathways Seamless knitted garment
Performance of the Sensor Sock Heel lift Toe off Heel strike Kinematic signal KRS sensor output Sensor sock with kinematic markers used for trials Sensor output and scaled kinematic signal against time for a single walking trial Sensor sock for monitoring of 3D foot orientation
Electronically active fibres/yarns Technology is based on the encapsulated area not exceeding 110% of the thread thickness
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)
Electronically Active Fibre/Yarn Technology Involves encapsulating micro-devices with a flexible hermetic seal for mechanical, thermal and electrical protection
Potential of the core technology Sensor Fibres Strain measurement Temperature measurement Fluid/gas measurement Radiation sensing Light measurement Acoustic measurement Motion detection Pressure measurement SMIT Active Fibres RFID Light emitting Vibration Magnetic Transmission Peltiers Intelligent Fibres Micro-controllers Micro-processors
Thank You 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 Contact details: Professor Tilak Dias Advanced Textiles Research Group Tel.: 0115 848 6518 Email: tilak.dias@ntu.ac.uk