Presented by Varun Kvarunkpa@gmail.com

USER INTRRACTIVE ELECTRONIC SKIN(E-SKIN) FOR INSTANTNEOUS

PRESSURE VISUALIZATION.

INTRODUCTION

What is ELECTRONIC SKIN?

Material which mimics the Human Skin in one or more ways.

Human skin can sense pressure , temperature , stretch and can heal itself

Where it is used?

ROBOTICS

HEALTH APPLICATION

SMART WALLPAPERS

DEVELOPMENT OF E-SKIN

• 2010:

I. Attaching nanowire transistors to sticky substrate, embedded in in thin pressure sensitive rubber-capable of sensing wide range of pressures(California University)

II. First prototype for e-skin

• 2011:

I. Stretchable solar cell used to power the electronic skin(Stanford)

• 2012:

I. Self healing capacity

II. Made by plastic and nickel

DEVELOPMENT OF E-SKIN(cont..)

I. No requirement of high temperature for self healing capacity.

E-SKIN FEATURES

• Optimization of pressure sensors & Electronic read out-but no Human Readable output.

• The new e-skin: Spatially map the applied pressure and instantaneous visual response through OLED.

• BUILT IN ACTIVE ORGANIC LED DISPLAY: OLEDs are turned on locally where the surface is touched and the intensity of the emitted light quantifies the magnitude of the applied pressure.

• System on plastic Demonstration 1.Thin film Transistor

2.Pressure sensor

3.OLED arrays

How Visual response is achieved?

Passive matrix

• Grid of vertical and horizontal lines

• Each pixel is controlled by an intersection of 2 wires

• Color and brightness is altered by changing electrical signal.

Active matrix

• Each pixel is controlled by TFT thin film transistors

• Act as switch for addressing either voltage or current devices

• TFTs contains Semiconductor enriched nanotubes as the channel materials.

• Carbon nanotubes-High current drives for OLEDs

Structure of pixel of e-skin

• Nanotube TFT drain connected to anode of OLED.

• OLED: Bi-layer structure whose color controlled by emissive layer material.

• PSR: Electrical contact with cathode of OLED.

• Conductivity of PSR αapplied pressure

Electrical performance of carbon nano tubes

L=20 um, W=2000 Vds=-5vOffset current of the transistor varies from 0.1 to 3uA.For this work this variation is acceptable. But can be again reduced by high purity nanotube.

OLED characteristics

• Led whose electroluminescent layer is organic compound.

• OLED Vs LCD

• Low power consumption, Faster refresh rate

• Better contrast

• Greater contrast, Brightness.

• Better durability-Better temperature range.

• By simply changing emissive layer the emitted peak wavelength can be adjusted to 489,523,562,601 nm.

How to control OLED

• Control ckt: By interconnecting the anode of an OLED with carbon nanotube TFT.

•By sweeping the gate voltage/Power supply Vdd of the control TFT, the current flowing through OLED can be controlled which translates in to the modulation of OLED brightness allowing the OLEDs to be turned ON and OFF.

AMOLED

• We can arrange above described single pixel OLED control circuitry in to an active matrix OLED which then integrated with pressure sensor to get e skin.

•Above figure represents Single color flexible AMOLED display with -5 and 10 v applied to all of the scan and data lines respectively

The above figure shows full color display being fully turned on in the relaxed and bent states.Each pixel can be individually addressed using nanotube tfts.

How to convert display in to e-skin

• PSR lamination on the top of the leads to make Pressure sensitive.

• The cathode of each OLED is connected to the ground through PSR. Application of pressure: shortening of tunneling path between conductive carbon nano particles-reduced resistance of PSR modulates the current flowing through the OLEDs and changes the brightness of the output.

I-V characteristics

Video Demonstration-eSkin

Electronic Skin.mp4

Advantages

• First demonstration of a user interactive flexible system that can not only detect the spatially map external stimuli but also respond with an integrated display.

• System enables sensed pressure profile to be instantaneously visible without the need for sophisticated data acquisition ckts and electronic boards.

APPLICATIONS

• Automatic control panel

• Interactive input devices

• Robotics

• Medical & Health monitoring device

THANK YOU