Polytronics - Seminar Paper

Abstract:

                    For many years plastics were well known merely as INSULATORS and were used predominantly for shielding copper wires. Now the emerging new technology POLYTRONICS, changes our viewpoint in visualizing the conducting polymers as a material of MICROELECTRONICS. 

                 Microelectronics technology in conjunction with silicon is flexible enough to easy rolling up of circuits that consume less power and above all they can be manufactured at a fraction of cost involved in making semiconductor chips. This technology has number of upcoming areas of interest where lot of research is going on to manufacture microelectronic components on plastic substrates which would allow manufacturing of gadgets through just printing process. In this paper I would like to impart my ideas on INKJET PRINTING TECHNOLOGY which plays main role in printing polymer circuits, ELECTRONIC PAPER, construction and manufacturing of Plastic batteries, medicinal applications of Polytronics using RUBBER CIRCUITS and ELECTRO ACTIVE POLYMER and ORGANIC LED (OLED). If this technology emerges practically, the world of electronics will take a new leap.

Introduction

                    In today’s world of ever-expanding technology, Polytronics is going to change the whole world of consumer electronics and form the principal root for the major advancement in the design of electronic circuits and manufacture of printed circuit boards (PCB).The era of polymer electronics has taken a great start and all the technological companies have turned their entire research towards Polytronics. We hope that, in the forthcoming years Polytronics will accelerate the pace of the technological advancements and describe a new dimension in the near future.

 Introduction:

                    Silicon has largely influenced the Electronics industry and would continue to do so over a period of time. However, technologists are now looking at other alternatives, mainly “PLASTIC CIRCUITS”, to meet our future needs. Here is a look into how plastics would influence the world of electronics.

The study of usage of polymeric materials in electronics is termed as “POLYTRONICS”.This polytronics has some advantages over silicon technology. They are

1. Easy Manufacturability (mass production).

2. Low cost.

3. They can be recycled and reused

        (decreases environmental stress).

4. Consumes less power.

5. They are mobile, small, and light in weight.

6. They are used to make display devices that have extraordinary picture quality.

       The feasibility of developing entire electronic components on basis of polymers is met by “INKJET PRINTING TECHNOLOGY” and is illustrated by several applications such as electronic paper, plastic batteries, etc.

Inkjet printing technology:

             The huge cost of manufacturing Silicon microchip is due to the large complex processes involved. Photolithographic techniques are used to pattern wafers with microcircuit, which is grown in powerful vacuum, while the wafers are baked at temperatures of several hundred centigrades.The INKJET PRINTING TECHNOLOGY provides continuous production line of plastic circuits on plastic substrates and then cut into individual units. The substrates are made of acetate material that is as transparent as vugraph sheets.This printing technology plays a major role in the development of “flat screen” displays. 

Principle

 A piezoelectric material expands when a voltage is passed across it, pressing on a reservoir fluid and sending droplets flying out on to the substrates.

Here, the construction of “TOPGATE TRANSISTOR” is explained below.

Construction of topgate transistor  

The water based droplets contain an organic conductor-POLY (3,4- ethylenedioxythiophene) doped with a solution of polystyrene sulphonic acid otherwise known as PEDOT/PSS.As the droplets dry they become a conducting layer and form source and drain of a transistor. They are then coated with a layer of semiconducting polymer (9, 9-dioctyl flourene-co-bithiophene) followed by a dielectric layer of polyvinylphenol.Finally gate is printed, creating a so called top gate transistor.

How the semiconductor polymer dries is very crucial. The molecular chains must line up in a way that makes it easy for an electron to hop from one chain to another, but the polymers tend to form into disordered microstructure that reduces electron charge.        

 Resolution of the screen can be improved by coating glass substrate with a hydrophobic film of polyimide pattern. When the water based droplets fall on the surface they are forced away from the hydrophobic regions in the required pattern.

Plastic batteries:

Plastic batteries are new type of low power batteries that do not require a case and are thin enough to be printed on a paper. They are of low cost and can be mass produced as the battery material is roughly 0.5 millimeters thick.

      

Construction:

• The new battery consists of 3 different layers.
• It has conventional zinc manganese dioxide components as anode and cathode which are thin foil-like plastic sheets.
• Electrolyte is a polymer gel placed between electrodes.

Uses:

• They can be used for incorporating power source in integrated circuits.
• The polymer battery system can be used to power space satellites, giving them uninterrupted power supply by harnessing solar energy while -

Organic light emitting diodes (OLED):

          Unlike traditional LCD’s, OLED’s are self-luminous and do not require backlighting, diffusers, polarizers or any other baggage that goes with liquid crystal displays. OLED consists of two charged electrodes on the top of some organic light emitting material. This eliminates the need for bulky and environmentally undesirable mercury lamps and fields a thinner, more versatile and more compact display. The low power consumption provides for maximum efficiency and helps to minimize heat and electric interference in electronic devices.  

There are two types of OLEDs:

• Passive matrix display
• Active matrix display

Passive matrix display:

The passive matrix OLED display has a simple structure and is well suited for low cost and low information content applications such as alpha-numeric displays. It is formed by providing an array of pixels by intersecting anode and cathode conductors.

Construction:

                             Organic materials and cathode metals deposited into a “RIB” structure(base and pillar) in which the rib structure automatically produces OLED display panel with desired electrical isolation for cathode lines. The major advantage of this method is that all patterning steps are conventional. So entire panel fabrication process can be easily adapted to large area, high through put manufacturing.

 Passive matrix display        

 To get a passive matrix OLED to work electrical current is passed through selected pixels by applying a voltage to the corresponding rows and columns from drivers attached to each row and column. An external controller circuit provides necessary input power, video data signal and multiplex switches. A video output is thus displayed on the panel by scanning through all the rows successfully in a frame time, which is typically 1/60th of a second.

Active display matrix:

    In contrast to the OLED matrix display, active matrix OLED display has an integrated electronic backplane, it lends itself to high resoluion, high information content applications including videos and graphics. This form of display is made possible by poly-silicon technology because of its high carrier mobility. It provides “Thin Film Transistors (TFT)” with high current capability and high switching speed.

Construction:

  The basic OLED cell structure consists of thin organic layers sandwiched between a transparent anode and a metallic cathode. The organic layer comprises a hole-injection layer, hole-transport layer, emissive layer and an electron transport layer. When appropriate voltage (2-10) V is applied to the cell, the injected positive and negative charges recombine in the emissive layer to produce light (Electron Luminescence).

The structure of organic layers and the choice of anode and cathode are designed to maximize the recombination process in emissive layer, thus maximizing the light output from the OLED device.

Advantages:

• Robust design: OLEDs are tough enough to use in portable devices such as cellphones, digital video cameras and DVD players..
• Production advantage: 20% to 50% cheaper than LCD processes.

Electronicpaper:  

          E-paper is a unique type of display whose flexibility, high contrast and bistability give it paper like functionality .These versatile displays are poised for dramatic growth across multiple application especially, in an “always-on” world of mobile broadband. Plastic electronics is the technology of choice for E-paper backplanes, especially for flexible and large displays. This technology overcomes the hurdle to large, high resolution, flexible electronic displays-the backplane. By connecting E-paper to the internet wirelessly with a phone or computer or LAN we can down load favourite newspapers and carry them all on sheet of paper.

        . .Polytronics Contributions:

1. Torpedoes contain a large circuitry which is to be protected from water .By using the POLYTRONICS we can make the Torpedo compact as there is no need for protection for the plastic circuitry.

2. Using POLYTRONICS, we can convert a big computer into a single polymer sheet, which contains a OLED display screen and mother board, processor and drivers at the back. This computer has some advantages over the existing computers and lap tops. They are 

Water proof

It can easily rolled 

Light in weight

3. We can construct a sensor system which can detect the position of submarine.

4. The present cell phones are not water resistance, by using POLYTRONICS we can make them water resistant as well as compact. 

CONCLUSION:

             In today’s world of ever-expanding technology, Polytronics is going to change the whole world of consumer electronics and form the principal root for the major advancement in the design of electronic circuits and manufacture of printed circuit boards (PCB).The era of polymer electronics has taken a great start and all the technological companies have turned their entire research towards Polytronics. So I conclude that, in the forthcoming years Polytronics will accelerate the pace of the technological advancements and describe a new dimension in the near future.