LIGHT EMITTING POLYMERS

PRESENTED BY:RASHIQUE KMH7152

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•INTRODUCTION•HISTORY•ARCHITECTURE•WORKING•MARIX DISPLAYS•MANUFACTURING•TYPES OF PLED•COMPARISON WITH LCD•ADVANTAGE•DISADVANTAGES•APPLICATIONS•FUTURE SCOPES

CONTENTS

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•LEP or PLED or P OLED

•Polymer which emits light(EM radiations).

•Polymers are chains of smaller molecular components called MONOMERS.

•CDT & UDC are developing LEP display.

INTRODUCTION

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•1977 conducting polymers are discovered. •Alan J. Heeger , Alan G. MacDiarmid got Nobel prize

•From this OLED evolved.

•In 1990 Friend et al found Electroluminescence in the conducting polymers.

•Birth of “LIGHT EMITTING POLYMERS”!

•Poly phinylene vinylene (PPV) is the first LEP discovered.

HISTORY

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•Thin film of semiconducting polymer sandwiched between an ANODE and CATHODE.

•ANODE: ITO(Indium Tin Oxide)

•CATHODE: Metals (depends upon the type of LEP)

•SUBSTRATE: Glass, clear plastic (depends upon the type of LEP)

•Voltage is applied between anode and cathode

ARCHITECTURE

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ARCHITECTURE

PolymerMetal Cathode

Glass Substrate

Transparent Anode (ITO)

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HOW IT WORKS

•Electroluminescence is the principle behind the LEP.

•Due to applied voltage electrons and holes will migrate to polymer lattice.

•They will combine together to form excitons

•Excitons returns to initial state by emitting radiation.

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HOW IT WORKS

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LEP FOR COMMERSIALISED DISPLAY

MATRIX DISPLAYS:

•PLED displays consists of matrix of pixels.

•Each pixel is a light emitting polymer.

•Emit light by turning OFF and ON the pixels.

•Primary color pixels are positioned very close to form other colored pixels

•To control each pixel DRIVERS are needed.

•DRIVERS are Transistors 9

MATRIX DISPLAYS

•PASSIVE MATRIX DISPLAYS

•ACTIVE MATRIX DISPLAYS

TWO TYPES OF MATRIX DISPLAYS

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PASSIVE MATRIX DISPLAY

•Each row and column have its own drivers.

•The organic layer is between strips of cathode and anode.

•Intersection forms the Pixel.

•Matrix scan every pixel to be switched on or off as required.

•Data signal is send to the pixel sequentially.

•If brightness is to increase, current through that electrode

will be increased.

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PASSIVE MATRIX DISPLAY

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PASSIVE MATRIX DISPLAY

• Easy to make.

•Use more power.

•If size of display increases..it will become difficult.

•Each pixel only emits light for a small length of time.

•Flickering is more.

•Only for small displays.

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ACTIVE MATRIX DISPLAYS

•Each pixel is addressed by incorporating a TFT.

•Brightness of each pixel is controlled by TFT.

•TFT will hold the current.

•Current flow is controlled by setting TFT drivers.

•More efficient than passive matrix displays.

•Can be used in large area displays.

•AMOLEP or AMOLED14

ACTIVE MATRIX DISPLAYS

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HOW IT IS MADE

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SPIN COATING METHOD

•Substrate is placed on spinning plate

•Plate is spinning at a speed of few thousand rotation per minute

•Robotic arm will pour small amount of polymer solution to the substrate.

•After spreading ,it is baked to evaporate any remaining liquid.

•Extremely fine layer of polymers having a thickness of about 100nm

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INK-JET PRINTING

•Ink-jet head, Ink and substrate for printing are different

•Primary colour polymers are jetted to the substrate.

•Uniformly spread the substrate.

•Mainly used for printing LEP images.

•Also used for making large display.

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INK-JET PRINTING

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TYPES OF LEP

•Flexible Organic Light Emitting Polymers(FOLEP).

•Stacked Organic Light Emitting Polymers(SOLEP)

•Transparent Organic Light Emitting Polymers(TOLEP)

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FLEXIBLE ORGANIC LEP(FOLEP)

•Built on a flexible substrate.

•They have the ability to conform, bend or roll a display into any shape.

•They are less fragile and more impact resistant.

•Ultra lightweight & thin form.

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FLEXIBLE ORGANIC LEP(FOLEP)

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TRANSPARENT ORGANIC LEP(TOLEP)

•Substrate is transparent.

•LEPs sandwiched between 2 transparent layers.

•Top and bottom emitting layers.

•High resolution.

•More than 70% transparent when turned off.

•Better efficiency.

•Faster response.23

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STACKED ORGANIC LEP(SOLEP)

•Array of vertically stacked TOLEP sub-pixels.

•Color is tuned by individually controlling R-G-B sub pixels

•Brightness is adjusted by adjusting the total current in the stack.

•It will only turn on the desired color pixel only.

•Can be used in large displays

•True color quality.25

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COMPARISON WITH LCD

Screen Refreshing Rates-

Viewing quality-

Screen size -

Viewing angle-

Power consumption-

Higher than LCD

Higher than LCD

Size is not limited in LEP display

Glare free up to 170 degree

Lesser than LCD

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ADVANTAGES

•Require only 3.3v for operation.•Low power consumption.•Self luminous.•No viewing angle dependence.•Manufacturing cost is less.•Can be scaled to any dimension.•No environmental draw backs.•Simple to use.•Very slim flat panel displays.

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DISADVANTAGES

•Voltage drops may affect the performance.

•Limited market availability.

•Aging of LEP• Degradation of luminescence• Light intensity gradually decreases.• Disintegrate due to contact with oxygen.

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FUTURE SCOPES

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IN CARS

LAPTOPS

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CONCLUSION

•Have both electrical and optical property

•A low cost solution for flat panel display.

•Many manufactures are working to introduce a revolutionary changes in the market.

•Hazardless to environment.

•Simpler and cheaper

•Have some limitations

•Till it is the superior technology………for the future…..

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REFERENCES

•http://en.wikipedia.org/wiki/OLED

•http://www.cdtltd.co.uk/

•“Inkjet Printing of Light-Emitting Polymer Displays” by Tatsuya Shimoda, Katsuyuki Morii, Shunichi Seki, and Hiroshi Kiguchi

•“LIGHT-EMITTING POLYMERS: THE REVOLUTIONARY DISPLAY TECHNOLOGY” by SHRINIVAS A. PATIL, ELECTRONICS FOR YOU, APRIL 2002

•“LIGHT EMITTING POLYMERS” by Dmitrii F. Perepichka,

•“Display Technology Overview” by Jeremy Gurski & Lee Ming Quach

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THANK YOU

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