AMOLED - Theory behind

You've heard the AMOLED term bunch of time when talking about the smartphones, or try to find out the characteristic difference while comparing with other mobile devices. Whether you already know AMOLED or not, here at ATCAPH you will find the complete information about AMOLED so that when someone says that its mobile having some sort of AMOLED, you know what exactly they are talking about.

What is AMOLED ?

AMOLED, stands for active-matrix organic light-emitting diode. It is a hybrid display technology that pairs the active matrix backplane from a traditional TFT display with an OLED display.

OLED describes a specific type of thin-flim-display technology in which organic compounds from the electroluminescent material, and active matrix refers to the technology behind the addressing of pixles. Each pixel has an active element (a thin-film transistor, or TFT) that actively provides current to the OLED, maintaining that pixel's brightness while the other pixels are being addressed. "Without the active matrix, OLED displays are small and low-resolution, used for applications like mobile phone sub-displayes."

AMOLED is a display technology for use in mobiles, Smartphones, tablets, televisions and continues to make progress toward low-power, low-cost and large-size applications.

Design and How AMOLED displays work ?

AMOLED displayes are inherently simpler and have only two main layers :

1. An OLED (organic light-emitting diode) layer that emits light upon electrical activation that have been deposited or integrated onto a thin-film-transistor (TFT) array.

2. A backplane, made of TFT(thin-film-transistor) circuits that provide current to the OLEDs, therby controlling their brightness. The two primary TFT backplane technologies, namely polycrystalline silicon (poly-Si) and amorphous silicon (a-Si), are used today in AMOLEDs.

Fig 1: Schamatic of an active-matrix OLED display.

Active matrix (AM) OLED displays stack cathode, organic, and anode layers on top of another layer - or substrate - that contains circuitry. The pixels are defined by the deposition of the organic material in a continuous, discrete "dot" pattern. Each pixel is activated directly: A corresponding circuit delivers voltage to the cathode and anode materials, stimulating the middle organic layer. AMOLED pixels turn on and off more than three times faster than the speed of conventional motion picture film -making these displays ideal for fluid, full-motion video.

AMOLED vs LCD which is best ?

LCD :

LCD stands for Liquid Crystal Display that uses the light modulating properties of liquid crystals, has been part of our lives for years now. Besides mobile devices we see LCD screens being used with almost every computer monitor, and in the majority of recent TVs. LCD screens produce some of the most realistic colors you can find on a screen, but might not offer as wide of a contrast ratio (darker get more darks and brighter more brighten). Some concern terms can be find associated with LCD displays are TFT and IPS. TFT stands for thin-film transistor which makes the wiring of LCD screens more efficient by reducing the number of electrodes per pixel. While on the other hand is IPS display which stands for In-plane Switching, which improves upon TFT by offering much wider viewing angles and color reproduction on LCD screens.

Fig 2: AMOLED pentile display (RGBG) vs LCD (RGB RGB) display.

AMOLDED :

AMOLED screen brought a perfectly black to screen technology for the first time, also by reducing power consumption. Amoled screens consist of a thin layer of organic polymers that light up when zapped with an electric current. Due to this simple construction, AMOLED screens can be extremely thin and don't require a backlight. AMOLED screens are sometimes called as "pentile" display. Instead of having just a single red, blue and green sub pixel per actual pixel, pentile displays have a RGBG sub pixel layout which has two green sub pixel for each red and blue.

Fig 3: Moto X with Super AMOLED HD display

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