Introduction to Epidermal Electronic System(E-Skin)

Mohammad Akter Hossain (244951)&

Nabid Faiem (238769)

Traditional ECG

Traditional EEG

Replacement of traditional with a noble approach…

Electronic Skin (E-Skin)

What is E-Skin?• E-skin is a ultrathin electronic device.• Light weight, Stretchable.• Attach to the skin like temporary tattoo.

E-Skin

• Mimic of human skin.• Physical properties (moduli, thickness and

others) should be matched with epidermis.• A thin film on epidermis-dermis bilayer

substrate.• https://www.youtube.com/watch?v=wvg-9aeS

TrE

Application of E-Skin

• Monitoring (EEG, ECG, EMG)• Wound measurement/treatment• Biological/chemical sensing• Human-machine interaction• Stimulation of certain tissue/organ

Application of E-Skin

Sectors on Thin film substrate

• Sensor • Power supply• Communication components• Interconnects exploit ultrathin layout (< 7µm)

Measurand Sense by Sensors

• Temperature • Strain • Electrophysiological parameter (ECG, EEG, EMG)

Basic Electronic Components

• Micro-scale light emitting diode (LED)• Active/Passive components (Transistor, diode, resistor)• Wireless power coils• RF communication module (High frequency inductors, capacitors, oscillators, antennae)

Sectors of E-Skin

E-Skin

Properties of Ultrathin Film(Substrate)

• Thin surface (around 30nm)• Gas permeable elastomeric sheet. It is based on

modified polyester. • Young Modulus is around 60kPa.• Robust adhesion with skin by only van der Waals

force.• Water absorbable polymer sheet ‘Polyvinyl Alcohol

(PVA)’.

Properties of Ultrathin Film(Electronics)

• Ultrathin layout (<7µm) of interconnection.• Electronics materials are based on Si or GaAs.• Filamentary serpentine shape of electronics.

Mechanical properties of EES(E-Skin)

• Depends on ‘effective modulus’ and ‘Thickness’ of both the circuit and sensor and the substrate.

• Effective modulus (EEES) can be expressed by-EEES = Eint(1 + Ld/Ls)

– Eint is the effective modulus of interconnects.– Ld is characteristic device size– Ls is distance between devices

• EEES can be minimized by reducing Eint and Ld/Ls.• Bending stiffness (EIEES) decreases with the thickness

of the device, interconnects and substrate.

Multifunctional Operation

• E-Skin is used to monitor Electrophysiological process (EEG, ECG).

• Applied sensor electrode incorporates with MOSFET.• FS design is used for this setup.• FS-MOSFET• Si based FS resistor• FS electrode

Multifunctional Operation

• The gate of a FS-MOSFET connects to an extended FS electrode for efficient coupling to the body potential.

• Analogous design based on rectangular device island.• FS interconnects via contact with the skin in a

common source amplifier configuration.

Multifunctional Operation

• Resistance based temperature sensors build with meander of Pt.

Multifunctional Operation

• In-plane strain gauges based on carbon black-doped Si.

Multifunctional Operation

Multifunctional Operation

• LED and photo detectors based on AlInGaP.

Multifunctional Operation

• Si FS photovoltaic cell able to generate few tens of microwatts.

Multifunctional Operation• Wireless powering via inductive effects act as an

alternative source.• FS inductive coil connected to a LED with

electromagnetic modeling of its RF response.• Able to charge the batteries or capacitors by RF coil.• Interconnected pair of FS inductors and capacitors

designed for RF operation.

Systems for Electrophysiological Recording

• Measurement of ECG, EMG and EEG in conformal, skin-mounted mode.

• No conductive gels or penetrating needles• Direct contact with skin • Biocompatible

Systems for Electrophysiological Recording

• ECG records from the chest, revealed high-quality signal.

• EMG is measured from leg muscle contraction.• EES mounted on throat can monitor muscle activity

during speech.• EEG is measured from the region of the forehead.

Future aspects

• In future, E-skin can be used to stimulate a certain tissue/organ, which is not able to receive commands from central nervous system (CNS).

• E-nose.• E-tongue.

Thank you