Technical data sheets for TVs and smartphones are often quite obscure, especially with regard to screen technologies. What is behind the names Amoled, LCD TFT or IPS? Here are our explanations.
Whether you choose a smartphone, a television or a computer monitor, the quality of the screen is one of the most important criteria. Knowing the different technologies is the best way to make a selection based on your needs and your budget.
Amoled screen technology
The Amoled (Active-Matrix Organic Light-Emitting Diode) or «Active Matrix Oled» screen uses the technical principle of the LCD screen in terms of individual pixel control but eliminating backlighting. Liquid crystals are replaced by organic light-emitting diodes that produce their own light under the effect of an electric current. This type of screen is characterized by the intensity of its colors, the depth of its blacks (because the pixels are then switched off) and the high level of contrast.
Moreover, the absence of backlighting reduces energy consumption compared to an LCD screen and makes it possible to manufacture slabs with a thinness of less than 5 millimetres. Since the response time is very short (less than 0.1 millisecond), the Amoled slabs do not produce a residual effect and offer an ideal fluidity for video games.
Those are the advantages, but there are also significant disadvantages. Amoled screens are much more expensive to produce because it is necessary to avoid any presence of moisture during the manufacturing process. Moreover, their service life is still largely perfectible (about 40,000 hours) compared to the LCD, mainly due to the degradation of the blue sub-pixels.
What is the difference between a TFT LCD and IPS?
An LCD screen consists of cells filled with liquid crystals that are illuminated by backlighting while filters set the colors. Each pixel of a screen consists of three sub-pixels red, green and blue. There are two categories of LCD screen:
- TFT or thin film transistor ;
- IPS or in-place switching.
TFT technology is widely used in computer screens, televisions and mobile devices. It is based on a thin film transistor matrix and an indium-tin oxide electrode that provide voltage control at each pixel, helping to improve response time and image stability. This is called an “active” matrix screen.
IPS technology is an evolution of TFT that was introduced by the Japanese firm Hitachi in 1996. It uses liquid crystals whose orientation varies to block or allow light from the backlight to pass through. This process makes it possible to improve the angle of visibility compared to a TFT screen but also to reduce energy consumption. In addition, IPS LCD displays offer brighter whites and brighter colors than TFT.
An LCD-only display uses TFT technology while an IPS display will mention this technology in its description.
In the end, if the Amoled technology is superior to the LCD, its still prohibitive cost is, for the moment, the main obstacle to its expansion. Some models of high-end smartphones and tablets use Amoled screens. On the television side, apart from LG, few manufacturers are firmly committed to the Oled market. The LCD technology still has good days ahead.