What is OLED?
OLED, which stands for Organic Light Emitting Diode, is a relatively new type of display for televisions, smartphones, and computer monitors. After only being invented in 1987, OLED is already one of the two top display technologies in the industry. OLED display technology uses organic (carbon-containing) compounds that emit light when a current is passed through it. OLED materials can be small molecule organic material or polymer material. OLED displays are known for their high picture quality, flexibility, and lower power consumption along with its premium price point. They are also extremely long-lasting with a lifespan of around 22 years if used 6 hours a day.
Since the Cathode Ray Tube (CRT) display was rendered obsolete, OLED’s only competitor has been the cheaper liquid crystal display, abbreviated LCD. However, OLED’s picture quality is substantially better with higher contrast ratio (also known as HDR high dynamic range) and larger viewing angles making it ideal for high-end electronics. OLED panels are also lighter and more flexible than LCD displays.
OLED vs. LCD
OLED has better image quality, contrasts, viewing angles, color accuracy, flexibility, and power-efficiency in comparison to LCD. OLED provides better color contrasts because it can create a pure black unlike LCD displays. LCD only works with backlighting. Backlighting is when a light is put behind a device in order to display an image. Because this backlight is always on, LCDs can never achieve a full-black like an OLED can. An OLED can show deeper and truer black levels.
Also because of the LED backlight, the power consumption of the OLED is less than that of LCD. OLED only emits light when electric current is passed through, so if there is no current, there is absolutely no light. OLED can also change the brightness of a picture pixel by pixel. Because of the limitation of the backlight, LCD displays can at best only dim the screen by small regions. This is because the only way to dim the picture is to reduce the brightness of the backlight, and it is not feasible to have a backlight for every pixel.
AMOLED ― Active Matrix OLED
An AMOLED display is an OLED display that is driven by an active matrix backplane, it is a type of OLED display that can achieve high performance.
AMOLED also light up pixels that are energized in both axes. Each pixel has switches made of transistors and capacitors connected to it to store power, and the voltage on the X axis controls the switching on and off.
Features:
1.The formation of semiconductor elements in each pixel complicates circuits and manufacturing processes, and increases costs.
2.Switches can prevent current leakage (crosstalk)
3.Since the voltage does not drop immediately due to capacitor storage, brightness can be maintained even when the duty ratio is shortened.
PMOLED ― Passive Matrix OLED
A PMOLED display uses a simple control scheme in which you control each row (or line) in the display sequentially (one at a time). PMOLED display do not contain a storage capacitor and so the pixels in each line are actually off most of the time. To compensate for this you need to use more voltage to make them brighter. If you have 10 lines, for example, you have to make the one line that is on 10 times as bright (the real number is less then 10, but that's the general idea).
So while PMOLEDs are easy (and cheap) to fabricate, they are not efficient and the OLED materials suffer from lower lifetime (due to the high voltage needed). PMOLED displays are usually small and are used to display character data or small icons: they are being used in wearable devices, small gadgets and sub displays.
Features:
1.Simple structure and low cost
2.Time-resolved dynamic drive (line sequential drive) requires higher voltage than AMOLED
3.The larger the screen, the shorter the duty ratio (time to apply voltage to each single pixel), and the lower the brightness.
Micro-OLED
Micro-OLED, also known as OLEDoS and OLED microdisplays, is one of the rare cases where the tech is exactly as it sounds: tiny OLED "micro" displays. Micro OLED displays are silicon-based OLED display that use a monocrystalline silicon wafer as the actively driven backplane, so it is easier to achieve high PPI (pixel density), a high degree of integration, and small size. This ensures they are easy to carry, have good anti-seismic performance, and have ultra-low power consumption.
On the backside of Micro OLED, it has an integrated CMOS driver circuit on the semiconductor, so it won't need an extra driver IC like LCD or OLED. Then it`s pixel pattern conducting layer above the CMOS circuit.
The other layers are just like OLED, from bottom to top, there are a lower electrode, an isolation layer, an organic light-emitting layer, and an upper electrode (for connecting cathodes of all pixels).
In a word, the white light and color filter layer is to generate FULL-COLOR images. The color filter layer is comprised of an RGB color filter and a black material matrix isolation strip.
The last step is to use a closed glass cover for encapsulation, a complete silicon-based OLED display comes out.
