There are different types of OLEDs.
1. Passive Matrix OLEDs (PMOLEDs)
These OLEDs have anode strips that are arranged perpendicular to the cathode strips. This
specific intersection makes up pixels that emit light. The brightness of each pixel is proportional
to the amount of the current applied. They are good to use in text displays, icon
displays and smaller screens such as mobile phone screens.
2. Active Matrix OLEDs(AMOLEDs)
They have a Thin Film Transistor (TFT) under the anode layer which forms a matrix. The
TFT array determines which pixel gets turned on in order to form an image. Typically, these
PMOLEDs are used for computer monitors, TV screens and electronic signs.
3. Transparent OLEDs
They are built using transparent materials. When this type of OLEDs are turned off, they are
transparent up to 85%. Once they are turned on, light can pass through in both directions.
They can be either active or passive matrix. These are mostly used for heads up displays
such as google or aircrafts.
4. Top Emitting OLEDs
They have a substrate that can either be opaque or reflective. They work better with active
matrix design. These are mainly used for smart cards.
5. Fordable OLEDs
In this type of OLEDs, the substrate is made using flexible metallic foils or plastic. They are
extremely lightweight and durable. Some cell phone companies have started using fordable
OLEDs for their products since they can prevent the breakage of the devices that they are in.
6. White OLEDs
They emit light that is brighter and more energy efficient than fluorescent lights. These
OLEDs can be used in lighting houses and buildings.
There are different types of
screens that are made up of OLEDs.
Since smartphones require a higher
refresh rate for HD images and other
frequently changing content,
they use AMOLED displays. Another
scenario where OLEDs are
used is devices like calculators with
PMOLED displays, which usually
display the same information on
the screen for a longer period than
a phone and refresh less often.
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University of Peradeniya GAUGE Magazine