ELECTRONIC DISPLAYPresented By:
Prof Sujatha B.M
Dept. of E&C,AIT
Department of Electronics & Communication,
Acharya Institute Of Technology
• Nicholas K. Sheridon invented Gyricon at
Xerox Palo Alto Research Center
(Xerox PARC), In the 1970’s
• Eventually became the basis of the
• Gyricon and E-paper never had much
success, but was on the right track.
3.Organic and Inorganic Conducting Layers
5.Thin Film Transistors
• The primary flexible substrate
candidates are plastics and thin glass.
• Plastic substrates are inexpensive, roll-
to roll processable and can be
laminated to multi-layers.
• Thin glass substrates exhibit better
thermal stability and have higher visual
transparency than plastics, but cannot
•Since flexible displays utilize organic materials, a barrier
layer is essential in protecting and enclosing the
functional materials and layers from oxygen and degraded
•Since organic materials tend to oxidize and hydrolyze,
oxygen and water permeation through a flexible substrate
is of particular importance flexible electronics.
3.Organic andInorganic Conducting Layers
• Indium tin oxide (ITO) is the typical conducting layer used in
display technology because of its excellent optical clarity.
• When ITO is deposited on a polymeric substrate, it can crack
under tensile strain and cause catastrophic failure.
• Conducting polymers are also being considered for flexible display
• There is a new conducting substrate technology based on
• The various types of electro-optic materials for flexible display fall
into three categories – emissive, reflective, and transmissive.
• In order to have a truly low power display, a reflection mode of
operation will have to be implemented on flexible substrates.
• Polymer-dispersed liquid crystals, encapsulated electrophoretics,
gyricon, and bi chromic ball composites all operate in the
5.Thin Film Transistors
• A thin-film transistor (TFT) is a special
kind of field-effect transistor.
• Made by depositing thin films of an
active semiconductor layer as well as
the dielectric layer and metallic contacts
over a supporting substrate.
• A common substrate is flexible glass.
• This differs from the
conventional transistor, where the
semiconductor material typically is the
substrate, such as a silicon wafer.
3.FLEXIBLE LCD DISPLAY
1. F-OLED DISPLAY
• Organic light emitting diodes
(OLED) display is another
promising technology for flexible
flat panel displays.
• Works on the principle of
• Flexible OLEDs are very
lightweight and durable. Their use
in devices such as cell phones and
PDAs can reduce breakage.
HOW IT EMITS LIGHT ??
1. Electrical current flows from the cathode to
the anode through the organic layers,giving
electrons to the emissive layer and
removing electrons from the conductive
2. Removing electrons from the conductive
layer leaves holes that need to be filled
with the electrons in the emissive layer.
3. The holes jump to the emissive layer and
recombine with the electrons. As the
electrons drop into the holes, they release
their extra energy as light. 23
F-OLED DISPLAY TYPES
• PM-FOLEDs have strips of
cathode, organic layers and strips
of anode. The anode strips are
arranged perpendicular to the
• The intersections of the cathode
and anode make up the pixels
where light is emitted.
• The brightness of each pixel is
proportional to the amount of
PASSIVE MATRIX OLED
F-OLED DISPLAY TYPES
• AM-FOLEDs have full layers of
cathode, organic molecules and
anode, but the anode layer
overlays a thin film transistor
(TFT) array that forms a matrix.
• The TFT array itself is the
circuitry that determines which
pixels get turned on to form an
• AM-FOLEDs consume less power
than PMOLEDs because the TFT
array requires less power than
external circuitry, so they are
efficient for large displays.
ACTIVE MATRIX OLED
2. GYRICON DISPLAY
• Gyricon are spherical beads with
one black and one white
• The spheres are only 100um in
diameter and make a display that is
only 200um thick.
• In the display, the beads are
dispersed in a transparent rubber
sheet and suspended in oil, allowing
it to rotate in response to an electric
• The electric field is applied by the
GYRICON DISPLAY WORKING
• When voltage is applied to the surface of the sheet, the
beads rotate to present one colored side to the viewer.
• Voltages can be applied to the surface to create images
such as text and pictures.
• The image will persist until new voltage patterns are
Comparison of Flexible Screens (F-OLED's) vs. LCD Screens (LED)
Cost Durability Weight Speed Applications
made of flexible
plastic. Hence it
to be just a thin
sheet of plastic.
applied to curved
or round services.
Low: Ability to
Fragile: Screen is
made of glass and
glass and more
a flat, straight