AMOLED displays: Introduction
Steven Van Slyke and Ching Wan Tang pioneered organic OLED at Eastman Kodak in 1979. The first OLED product was a display for a car stereo , released by Pioneer in 1997. Kodak’s EasyShare LS633 digital camera, introduced in 2003, it was the first consumer electronics product to feature a full color OLED display. The first TV with an OLED screen, produced by Sony, entered the market in 2008. Currently, Samsung uses OLED in all its smartphones and LG makes large OLED screens for premium TVs . Other companies currently incorporating OLED technology include Apple, Google, Facebook, Motorola, Sony, HP, Panasonic, Konica, Lenovo, Huawei, BOE, Philips, and Osram.The OLED display market is expected to grow to $57 billion by 2026.
AMOLED (Active Matrix Organic Light Emitting Diode) is a type of OLED display device technology. OLED is a type of display technology in which organic material compounds make up the electroluminescent material, and active matrix is the technology behind individual pixel addressing.
An AMOLED display consists of an active array of OLED pixels that generate light (luminescence) upon electrical activation that have been deposited on or embedded in a Thin Film Transistor (TFT) array, which functions as an array of switches to control the current flowing to each individual pixel.
Typically this continuous current flow is controlled by at least two TFTs in each pixel (to trigger the luminescence), with one TFT to start and stop charging a storage capacitor and the second to provide a voltage source to the level necessary to create a constant current to the pixel, thus eliminating the need for the very high currents required for PMOLEDs .
TFT backplane technology is crucial in the manufacturing of AMOLED displays. In AMOLED, the two main TFT backplane technologies, polycrystalline silicon (poly-Si) and amorphous silicon (a-Si), are currently used and offer the potential to directly fabricate active matrix backplanes at low temperatures (below 150° C) on flexible plastic substrates to produce flexible AMOLED displays. The brightness of AMOLED is determined by the strength of the electron current. Colors are controlled by red, green, and blue light-emitting diodes. It’s easier to understand by thinking that each pixel has an independent color, mini-LED.
What are the advantages and disadvantages of an AMOLED screen?
Benefits of an AMOLED:
-No backlight means AMOLED can display any area needed and less power consumption and longer battery life.
-No backlight means AMOLED can achieve a very slim profile display.
-No backlight means there is no backlight that can provide bright and vibrant colors to the human eye.
-No backlight, which means the background can have deep blacks and high contrast.
-AMOLED does not like LCD has a viewing angle problem that has all viewing angles.
-AMOLED does not like that the LCD screen has response problems. It does not have the image lag and has a very fast response time.
Negative points of using an AMOLED:
-AMOLED is more expensive to produce than TFT, the cost is high, so it can only be used for high-end products.
-AMOLED has a shorter lifespan than TFT and also has burn-in issues.
-AMOLED uses color mixing to obtain a white color that may appear yellowish.
-AMOLED panels are affected by the presence of water.
-AMOLED needs to be run hard to get higher brightness. OLED outdoor sunlight is not readily available.
IPS TFT Screens: Introduction
Surprisingly, the TFT IPS (In Plane Switching) screen was invented much later than AMOLED. TFT IPS LCD was developed by Hitachi in Japan in the mid-1990s.
IPS technology is like an improvement on the traditional TFT LCD display module in that it has the same basic structure, but with more enhanced functions and more widespread usability compared to the previous generation of TN type TFT display (commonly used for low cost applications). computer monitors). Actually, it’s called super TFT. The IPS LCD screen consists of the following high-end features. It has much wider viewing angles, more consistency, better color in all viewing directions, higher contrast, and faster response time. But IPS displays are not perfect due to their higher manufacturing cost compared to TN TFT LCDs.
LCD screen TFT TN (Thin-Film-Transistor Liquid Crystal Display) has a sandwich structure with liquid crystal material filled between two glass plates. Two polarizing filters, color filters (RGB, red/green/blue), and two alignment layers determine exactly how much light is allowed to pass through and what colors are created. Each pixel in an active matrix is combined with a transistor that includes capacitors that give each sub-pixel the ability to hold its charge, rather than requiring an electrical charge to be sent each time it needs to be switched. The TFT layer controls the flow of light, a color filter displays the color, and a top layer houses your visible screen.
Using an electrical charge that causes the liquid crystal material to change its molecular structure allowing various wavelengths of background light to “pass through”. The TFT display’s active matrix is in constant flux and changes or updates rapidly based on the incoming signal from the control device.
IPS LCDs, unlike TN LCDs, place both electrodes at the same level, behind the liquid crystal layer. When the electric field is applied, this forces the liquid crystal molecules to align parallel to the layers of the IPS device instead of perpendicularly like the TN molecules.
Opposite to TN, when the electric field is applied, IPS technology will polarize the light to pass , while when the electric field is not applied, the light will not be polarized to pass. Due to the orientation of the glass, IPS displays require brighter, more powerful backlights to produce the correct amount of brightness for the screen.
What are the advantages and disadvantages of an IPS TFT screen?
Benefits of an IPS TFT screen:
-IPS TFT LCD has lower cost manufacturing processes and the price is more affordable.
-Many manufacturers can produce IPS LCD screens, which means a wide range of standard sizes available on the market and customization is also less expensive than AMOLED.
-IPS TFT display uses backlight which can have the flexibility to use high-efficiency LED lamp and can easily get a sunlight-readable display.
Negative aspects of an IPS TFT screen:
-The IPS TFT screen uses backlighting, which limits the contrast ratio.
-IPS has much better viewing angles compared to TN TFT, but color inversion can still be poorer compared to AMOLED, especially at extreme viewing angles.
-The IPS TFT screen uses backlight, which makes the screen not completely black for the background.
-IPS TFT screen responds slower than AMOLED screens, especially in low temperature environments.
In conclusion
AMOLED and IPS LCD have their own advantages and disadvantages . Choosing one display technology over another should be purely a matter of personal preference.
Apple started with the iPhone X and is moving to AMOLED screens. Samsung is the largest AMOLED manufacturer in the world. Of course, Samsung is also the biggest user and proponent of using AMOLED in all Samsung Galaxy Note, Android phones and watch series. Samsung even developed S-AMOLED (Super AMOLED displays), which are AMOLED screens that have built-in touch: instead of having a capacitive touchscreen that recognizes touch on top of the screen, the overlay is built right into the screen. same. Of course, it adds to the cost of the premium.
We predict that AMOLED and will coexist in our market for a long time, making the world more colorful and beautiful.