POLED & AMOLED: The OLED Technologies

In today’s world the Display panel terminology is growing & expanding day by day & hence making it tougher for its users to easily understand the actual technology behind them. People sometimes also get confused about these terminologies & different types of displays present around them which in turn prove out to be a bad deal in some cases. Now as companies have also started producing POLED’s i.e plastic OLED displays which will be a very new thing to understand for the users. A company like Samsung which is very well-known for marketing its Super AMOLED display technology which is also known for forming the backbone of its very latest curved edge smartphone designs. So you should know something about the technologies of the POLED and AMOLED.

OLED Display Technology Theories (AMOLED & POLED)

For a better understanding of these newer display technologies, firstly you must have a better understanding of the basic OLED tech & leave behind the P of POLED & AM of AMOLED for some time. So let’s get started with the basic now:

The OLED Tech

• The display panels are built from millions of Organic Light Emitting Diodes, the little components that light up when current passes through them.
• These diodes are aligned in various red, green & blue configurations which then may combine & produce a full range of colors.

• The excellent contrast ratio is obtained with these light-emitting diodes as they can be switched off completely when needed thus giving complete deep blacks. (LCD’s can’t give deep blacks as they don’t get completely switched off).
• Current is passed to these pixels using two methods: a passive wiring matrix or an active wiring matrix.
• The Passive matrix displays at one time provide current to an entire row of LED that is cheap, not ideal while the Active matrix allows each pixel to get driven individually at particular voltages through the introduction of a Capacitor & a thin filmed Transistor network.

• The driving matrix is part of the panel which is on the top of the substrate that is usually a glass.
• For more detailed information regarding the subject OLED please refer to our previous article under the section Tech Ivagination: Let’s Know About OLED Display.

The AMOLED Tech

• Though today, all the Smartphones & other high-resolution displays of the same size need to use an Active matrix technology (as Passive matrix needs higher voltages for introducing more pixels, which also degrades LED’s life & so can’t be used for higher-resolution display panels).

• If you have understood the above-stated theories related to the smartphone displays, then you can simply guess out the Samsung’s AMOLED tech now i.e Active Matrix OLED.
• For more detailed information regarding the subject AMOLED please refer to our another article under the section Tech Ivagination: Let’s Know More About AMOLED Display.

The POLED Tech

• As we told you about the glass substrates being used in the OLED panels or AMOLED panels, so the desire to achieve more interesting form factors, this glass substrate seems moving on to much more flexible plastic components as a layered structure of the OLED display.
• With the glass as substrate we can only get fixed & rigid displays & as per today’s demands everything we want is much more flexible for easy handling, these plastic substrates can play a very important role in order to achieve flexible as well as new forms & new shaped displays.

• Although being much more cost effective than the traditional method of molding glasses, different range of plastics have been experimented.
• A wide range of plastics tested for producing flexible displays includes the very commonly used PET’s (poly ethylene terephthalate) & the PEN’s (poly ethylene naphtholate).
• However while using the material of plastic for substrate preparation, it is also very important to keep in mind about the type of TFT techs being used.
• For proper accommodation of both the substrate to the TFT, either the manufacturing temperatures should be lowered or such plastic be used which can easily withstand higher temperatures.

• So after much research & experiment, Polyamide plastics are being used by the POLED manufacturers to produce flexible displays.
• The type of Substrate & heating process also plays a very important role in defining the flexibility of the display.

The Future Tech

Although you all have already gone through the thorough introductory part for OLED, AMOLED & POLED after which most you have recognized the various upcoming advanced technologies built-in to various devices. But being a POLED it remains very flexible & in the same way it may also differ with its performance characteristic as on the TFT side, a-Si & more expensive poly-Si i.e based on LTPS or both may be used for driving such flexibility. Also, the LTPS technology is better suited for OLED panels because of its higher electron mobility when compared to a-Si, which is important for driving current hungry LEDS. This can even differ in characteristics based on the manufacturing techniques used.

Nowadays all of us are very much aware of the upcoming curved display techs from two major manufacturers & there is some confusing part, that Samsung’s edge AMOLED displays are built on plastic substrates with poly-Si TFT technology, such as the one inside the Galaxy S8. LG Display’s POLED technology is clearly using plastic and poly-Si is assumed for adequate performance too. So it’s absolutely possible to build a plastic substrate, active matrix OLED panel, and that’s what both of the big two panel manufacturers are doing when it comes to curved mobile displays.