new way to display technology...

3. WELCOME
•

4. By
VISHNU MOHAN V.M
Seminar guides,
Athira A.P
Divya nateshan

5. AGENDA
INTRODUCTION
HISTORY
ABOUT LEP
ARCHITECTURE
WORKING
MARIX DISPLAYS
MANUFACTURING
TYPES OF PLED
COMPARISON WITH LCD
ADVANTAGE
DISADVANTAGES
APPLICATIONS
FUTURE SCOPES

6. INTRODUCTION
 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.

7. HISTORY
 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.

8. About LEP………..
Electroluminescence is the principle behind
the LEP.
LEP comes under the category of
conjugated polymers.
Polymers with metallic and
semiconductor characteristics.
Delocalized pi electrons
Band gap ranges from 2.2 to 2.8 ev
Wave length depends on the band gap of
LEP.

9.  Thin film of semiconducting
polymer sandwiched between an
ANODE and CATHODE. Metal Cathode
Polymer
 ANODE: ITO(Indium Tin Oxide)
 CATHODE: Metals (depends upon
the type of LEP)
Glass Substrate
 SUBSTRATE: Glass, clear plastic
(depends upon the type of LEP) Transparent Anode (ITO)
 Voltage is applied between anode
and cathode

10.  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.

12. 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
• 2 matrix

13. TWO TYPES OF MATRIX DISPLAY SYSTEMS
 PASSIVE MATRIX DISPLAYS
 ACTIVE MATRIX DISPLAYS

14. 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 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.

15. Passive matrix displays……
 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.

16. 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 AMOLED

17. HOW IT IS MADE………………………………….?

18. • Substrate is placed on spinning
STEP 1 plate.
• Plate is spinning at a speed of
few thousand rotation per
STEP 2 minute.
• Robotic arm will pour small
amount of polymer solution to
STEP 3 the substrate.
• After spreading ,it is baked to
STEP 4 evaporate any remaining liquid.
• Extremely fine layer of polymers
having a thickness of about
STEP 5 100nm

19.  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.

20. TYPES OF LEP……….(PLED)
 Flexible Organic Light Emitting
Polymers(FOLEP).
 Stacked Organic Light Emitting
Polymers(SOLEP)
 Transparent Organic Light Emitting
Polymers(TOLEP)

21. 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.

23. 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.

25. 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.

26.  Screen Refreshing Rates  Higher than LCD
 Viewing quality  Higher than LCD
 Screen size  Size is not limited in LEP
display
 Viewing angle  Glare free up to 170
degree
 Power consumption  Lesser than LCD

27. ADVANTAGES…..
 Require only 3.3v & life time of more than 30,000 hr.
 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.

28. 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.

29. APPLICATIONS……
 Multi or full color cell phone displays
 Full color high-resolution personal digital
assistants(PDAs)
 Lightweight wrist watches
 Roll-up daily refreshable electronic newspapers
 Automobile light systems without bulbs

30. FUTURE SCOPES….
 LEP-in future cars


31. LAPTOPS……

32. TELEVISIONS…

33.  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…..