AMOLED Display

By Mehdi | Updated : (Oct 21, 2019)

Active Matrix Organic Light Emitting Diode (AMOLED) is a technology used in the display screen of smart watches, mobile devices, laptops and televisions. here, organic light emitting diode(OLED) refers to a particular type of thin-film-display technology in  which electroluminescent material is formed by the organic compounds and active matrix means to the technology used in addressing of pixels.

This technology is in use since 2008. it has been used for mobile phones, digital camera and media players. From the day it came into use till now, it is continuously progressing to serve low-power, high resolution, low-cost and large-size particulars in the respective devices.

Designing

An active matrix of OLED pixels which generates light upon electrical activation that have been deposited or integrated onto a thin-film transistor (TFT) array constitutes the AMOLED display that functions as a series of switches to control the flowing of current to each individual pixel.

The continuous current flow is monitored by at least two TFTS at each pixel to trigger the luminescence. The first TFT starts and stops the charging of storage capacitor and the second to provide a voltage source at the level needed to create a constant current to the pixel, eliminating the need for the very high current required for passive-matrix OLED operation.

Future Development

In the fabrication of AMOLED displays, TFT backplane technology is very crucial. Two primary TFT backplane technologies, polycrystalline silicon (poly-si) and amorphous silicon (a-si),are used currently to directly fabricate  the active matrix backplanes at low temperature on the flexible plastic substrates for producing flexible AMOLED displays.

Comparison to prevalent technologies

In the AMOLED fabrication process, in-cell touch panels are developed integrating the production of capacitive sensor arrays. AU Optronics and Samsung include the in-cell sensor AMOLED fabricators. Samsung is trading its version of technology as “super AMOLED”. Researchers at DUPONT used CFD (Computational fluid dynamics) software to amplify the coating process for a new solution-coated AMOLED display technology which is giving competition in cost and performance with the current chemical vapor deposition (CVD) technology. Samsung has also developed long and short-range film thickness control and uniformity which is commercially viable at glass sizes using custom modeling and analytic approach.

It provides higher refresh rates than passive matrix reducing response time to less than a millisecond while consuming less power.

AMOLED display is not clearly visible as LCDs because of their minimized brightness range. Super AMOLED developed by Samsung address this issue by reducing the gap between layers of the screen. The organic substance used in AMOLED are degraded easily in a very short duration of time. Resulting in color distortion as one color fades faster than other which results in color shift. This leads to image persistence or burn-in effects.

Marketing Terms

Super AMOLED

This term is used as a marketing term by the device manufacturers of AMOLED display with an integrated digitalizer.the touch detection layer is integrated into the screen rather than laid over the top. In Samsung words, “the super AMOLED SCREENS deflects one-fifth sunlight as the first generation AMOLED .super AMOLED is a member of penTile matrix family. It is abbreviated many times as SAMOLED.

Super AMOLED Advanced

this is a term marketed by Motorola to present a more pronounced display than super AMOLED screens, but also a higher resolution-qhd or 960/ 540 for super AMOLED advanced than WVGA or 800/480 for super AMOLED and are 25%more energy efficient. Super AMOLED advanced have penTile provides a higher resolution display by sharpening sub pixels in between pixels. But while sharpening the sub pixels the, picture quality is lost. This type of display is used in Motorola droid RAZR and HTC one S.

Super AMOLED Plus

The super AMOLED plus, has been introduced along with Samsung galaxy S II and Samsung Droid Charge Smartphone, is used as a branding by Samsung where the penTile RGBG pixel matrix (2 sub pixels) which was  experimented in SUPER AMOLED display has been replaced with a traditional RGB  (3 SUBPIXELS) arrangement used in LCDs typically. This new variant is brighter and more energy efficient than super AMOLED displays and generates punchier and less grainy images because of increase counts of sub pixels. When compared with AMOLED and super AMOLED displays, it is more energy-efficient and brighter.

HD Super AMOLED

Samsung branded HD super AMOLED for an HD-resolution (above 1280/720) super AMOLED display. The first device to use the display was Samsung Galaxy Note. The galaxy nexus and the galaxy S III both uses the HD super AMOLED with a pentile RGBG-matrix (2 sub pixels/pixel), but Galaxy note II uses an RBG matrix (3 sub pixels/pixels), not in the standard 3 stripe arrangement.

HD Super AMOLED Plus

a version of the Samsung s3 using Tizen OS 1 WAS benchmarked using a non-penTile HD super AMOLED plus screen in 2012.

Full HD Super AMOLED

Samsung galaxy s4, Samsung galaxy s5, and Samsung galaxy note 3, featured the display that has a resolution of 1920/1080 which is better known as 1080P.

Quad HD Super AMOLED

In April 2014, AU Optronics used Quad HD super AMOLED screen .after AU OPTRONICS launched its phone having a QUAD HD super AMOLED screen, the other companies including Samsung released phone equipped with the technology. The phone models that were released at that time were Samsung galaxy note 5 broadband LTE-A and Samsung galaxy S6 and S7.

Future

Future displays shows flexible, 3d, unbreakable, transparent super AMOLED plus displays exhibited by Samsung using very high resolution and in varying sizes for phones. These unlaunched prototypes used a polymer as a substrate eliminating the need of glass cover, a metal backing, and touch matrix, combining them into one integrated layer.

In future, 3D stereoscopic displays are modeled that use eye-tracking to provide full resolution 3D visuals