ELECTRONIC SKIN: A MODEL FOR THE NEW FUTURE

 ELECTRONIC SKIN

“Technological innovation is indeed important to economic growth and the enhancement of human possibilities.”

 Electronic skin is flexible, stretchable, and self-healing electronics that are able to mimic functionalities of human or even animal skin.  As we all know skin is the largest organ in our body and has a wide variety of interesting properties such as stretchability, self-healing ability, tactile sensing capability, and high mechanical toughness.

Electronic skin or e-skin is a device that mimics such properties of human skin along with additional features.

Electrical skin technology

The applications of e-skin vary widely. The key application areas are in the wearable or skin attachable devices, prosthetics, and robotics. The broad class of materials often contains sensing abilities that are intended to produce the capabilities of human skin to respond to all environmental factors like changes in heat, temperature, and pressure.

Madhu Bhaskaran, research leader says that the pain-sensing prototype is a significant advance towards next-generation  biomedical technologies and intelligent robotics.

No electronic technologies have been able to realistically mimic that very human feeling of pain. We sense the things all the time through the skin but our pain response only kicks in at a certain point, such as when we touch something too hot or too cold.

·       Stretchable electronics, which combine oxide materials with biocompatible silicon to deliver transparent, wearable, and unbreakable electronics, thin like a stickers.

·       Self-modifying coating 1000 times, even thinner than our hair, based on a material that transforms in response to heat.

·       Electronic memory cells that imitate the way the brain uses long term memory to recall, and also retain previous information.

When electronic skin is attached to human skin or is functioning as skin in prosthetics or robotics, first, they need to well adhere to moving surfaces. At the joints, the surface will undergo lateral tension, twisting, and compression.  For the electronic skin to have adhered to the body under such conditions,  stretchability is of a critical matter. Without this stretchability, the electronic skin is likely to be delaminated from the surface.

Electrical Skin

For skin-attachable applications, since stretchable materials can stretch along with the surface of the skin. The user will experience higher comfort. In addition to it, stretchability is needed to provide the necessary mechanical degrees of freedom to prevent the breakage of electronic skin during usage.

When electronic skin is attached to human skin or is replacing skin in prosthetics. The daily human motion will generate strain values up to 30%, without stretchability, the electronic skin will likely undergo serious damage. In the case of robotics, the stretchability of electronic skin will enable the robot to take on a variety of shapes and it enables a high degree of freedom in movement.

Our skin has several unique properties that distinguish it from conventional electronics. In addition to that, our skin is capable of repairing itself, drastically increasing its durability and its lifetime.

E-skin will be exposed to a variety of mechanical stresses, causing strains in various directions. Hence, it is imperative that the electronic skin maintains its functionality under such strains. Regards that, research on stretchable electronic materials and devices has been intensively investigated, and huge improvements have been witnessed over the past few years.

Electronic skin features:

·        Optimization of pressure sensors

·        Electronic readout but no Human Readable output

·        Built is an 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 applied pressure.

·        It can measure the electrical activity of the heart, brainwaves, and other vital signs.

·        record electrical activity along the scalp.

·        Muscle contraction in the neck, control the mouse in a computer game

Structure of pixel of electronic skin

·       OLED: bi-layer structure whose color controlled by emissive layer materials.

·       The nanotube TFT drain is connected to the anode of OLED.

·       Conductivity of PSR (alpha) is applied pressure.

AMOLED

We can arrange single-pixel OLED control circuitry in to an active matrix OLED which is then integrated with the pressure sensor to get a skin.

Each of the pixels can be individually addressed using nanotube TFTs.

Method to convert display into electronic skin

There is 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 the pressure: shortening of tunneling path between conductive carbon nanoparticles reduce the resistance of PSR modulates the current flowing through OLEDs and it also changes the brightness of the output.

Advantages

·        It reduces the wires

·        It is compact in size

·       Less in weight

·       Device is Floppy

·       Device is also Flexible

Disadvantages

·        It’s cost is high

·        Single use

Applications of electrical skin

·    In Automatic control panel

·     In interactive input devices

·    In robotics

·     In medical devices

·    In health monitoring devices

Future scope of e-skin

In the future, even the virtual skins may be placed on the device for knowing our body functionality.

“Whenever you take technology and mix it with art, you always come up with something innovative.”