Types of Display

What is Display

A display is a computer output surface and projecting mechanism that shows text and often graphic images to the computer user, using a cathode ray tube ( CRT ), liquid crystal display ( LCD ), light-emitting diode, gas plasma, or other image projection technology. The display is usually considered to include the screen or projection surface and the device that produces the information on the screen

The screen, when combined with the touch element, is 'the' major element of the user interface and as such we go to great lengths when testing screens during our review process to measure a displays quality by measuring Contrast Ratio, Color Calibration, Brightness and Sunlight Legibility.

Types of Display

There are mainly Four types of disply

• LCD (Liquid Crystal Display) 
• IPS-LCD (In-Plane Switching Liquid Crystal Display) 
• OLED (Organic Light-Emitting Diode) 
• AMOLED (Active-Matrix Organic Light-Emitting Diode)

1. LCD (Liquid Crystal Display) :

LCD is a electronic display device that operates by applying a varying electric voltage to a layer of liquid crystal, thereby inducing changes in its optical properties. LCDs are commonly used for portable electronic games, as viewfinders for digital cameras and camcorders, in video projection systems, for electronic billboards, as monitors for computers, and in flat-panel televisions.

Segment code LCD screen was developed in Japan in the early stage and introduced into China in the 1980s. It is mainly used to replace LED digital tubes (composed of 7 pen segments, used to display Numbers 0-9), such as calculators and clocks. The display contents are all Numbers and relatively simple.

This has become a common display type for mid-range to high-end phones.

2. IPS-LCD (In-Plane Switching Liquid Crystal Display):

IPS, also known as In-Plane Switching, is a type of monitor display and screen technology. More specifically, an IPS panel is a type of TFT LCD (or "active matrix" LCD). LCD, or Liquid Crystal Display, is the use of light modulating properties from unlit liquid crystals for providing a flat panel or electronic visual display. TFT, which stands for Thin Film Transistor, is an LCD display variant built and marketed for enhanced color, as well as contrast and black levels. The two most common types of TFT LCDs are IPS and TN displays.

The level is the index standard that expresses liquid crystal display screen brightness intensity, namely the color index that says commonly. Now the market generally sees three-color quality: 256 colors, 4096 colors, and 64K(namely 65536) color and even higher 260,000 colors. The display effect of different color quality is different. Displays are divided into three categories: plain text, simple images (like cartoons, mostly menu charts, and drawn standby), and photo images. For users with higher photo quality requirements, 64K color is certainly a better choice.

3. OLED (Organic Light-Emitting Diode):

OLEDs are electronic devices that employ a series of thin, light-emitting films composed of hydrocarbon chains, rather than semiconductors laden with heavy metals like gallium arsenide phosphide as in existing LED technology. These organic arrays between two conductors with different work functions produce bright light by utilizing less energy [12]. The structure of OLEDs was initiated with a single layer and gradually evolved to double layer and triple layer and to their current multilayer anatomy

OLED screens display images by emitting light from pixels. In this respect, OLED screens are more technologically advanced than LCD screens. In addition, the thickness of the OLED screen can be made thinner, which is conducive to the thickness control of the whole machine. On the whole, they can be classified as LCD and OLED in a wide range. The two kinds of screens are essentially different from each other in terms of luminescence, one is illuminated by external light sources, the other is self-emitting light.

They consume less power as opposed to LCDs which always have the back-light on. When a pixel is 'black' on a OLED/AMOLED display the pixel is truly off.

4. AMOLED (Active-Matrix Organic Light-Emitting Diode):

AMOLED (active-matrix organic light-emitting diode) is a display technology used in smartwatches, mobile devices, laptops, and televisions. OLED describes a specific type of thin-film-display technology in which organic compounds form the electroluminescent material, and active matrix refers to the technology behind the addressing of pixels.[1] Active matrix organic light-emitting diodes (AMOLEDs) consist of pixels of electroluminescent organic compounds “printed” in a matrix onto a base layer. This base layer is currently glass and will be further developed to use flexible polymers in the future. Unlike liquid crystal displays, OLED displays do not require a backlight and consume very little power, making them suitable for battery-powered devices. AMOLEDs use a thin film transistor (TFT) to control the pixels.

AMOLED utilizes 'organic' LEDs which emits light and in the majority of cases does away with the need for the back-light of an LCD display resulting in a potentially thinner panel. It provides less washed out 'blacks' with a better contrast ration and is highly visible in low light conditions.