The Monitors using TFT are known as TFT-LCD monitors. The display of TFT monitor has two Glass substrates enclosing a layer of liquid crystal.
What is TFT Screen:
TFT displays are found in many applications these days, from mobile devices, appliance, medical devices, instrumentation, aircraft and certainly computer display devices as well as TV’s. The addition of the thin film transistor in LCD design vastly improved the use of LCD’s in all market areas.
Organic Electro Luminescent Display Based on the construction, OLED can be classified into Top emitting OLED – Its Substrate layer may be either reflective or non reflective. White OLED – It emits only White light and makes large lighting systems. Foldable OLED – Ideal to make Cell phone display since it is flexible and foldable.Active Matrix OLED The Anode is a transistor layer to control the pixel. All the other layers are similar to the typical OLED.Passive OLED – Here the external circuitry determines its pixel formation
A display screen made with TFT (thin-film transistor) technology is a liquid crystal display (LCD), common in notebook and laptop computers, that has a transistor for each pixel (that is, for each of the tiny elements that control the illumination of your display). Having a transistor at each pixel means that the current that triggers pixel illumination can be smaller and therefore can be switched on and off more quickly.
TFT is also known as active matrix display technology (and contrasts with “passive matrix” which does not have a transistor at each pixel). A TFT or active matrix display is more responsive to change. For example, when you move your mouse across the screen, a TFT display is fast enough to reflect the movement of the mouse cursor. (With a passive matrix display, the cursor temporarily disappears until the display can “catch up.”)
A more recent development is organic thin-film transistor technology, which makes it possible to have flexible display surfaces.
Thin Film Transistor (TFT full form) monitors are now popular in Computers, TV, Laptops, Mobile phones etc. It gives enhanced quality of images like contrast and address-ability. Unlike the LCD monitors, TFT monitors can be viewed from any angle without image distortion. TFT display is a form of Liquid Crystal Display with thin film transistors for controlling the image formation. Before going into the details of TFT technology, let us see how the LCD works.
How it differ from LCD:
The LCD contains Liquid crystals which is a state between liquid and solid. That is the matter can change its form from liquid to solid and viceversa. The liquid crystal flows like a liquid and it can orient to form the solid crystal. In the LCD displays, the liquid crystals used have the property of light modulation. The LCD screen do not emit light directly but it has a number of pixels filled with liquid crystals that pass light. These are arranged in front of a Back light which is the source of light. The pixels are distributed in columns and rows and the pixel behaves like a capacitor. Similar to a capacitor, the pixel has a liquid crystal sandwiched between two conductive layers. The images from The LCD may be Monochrome or colored. Each pixel is connected with a switching transistor.
When compared to the ordinary LCD, TFT monitors give very sharp and crisp text with increased response time. The TFT display has transistors made up of thin films of Amorphous silicon deposited on a glass using the PECVD technology. Inside each pixel, the transistor occupies only a small portion and the remaining space allows the passage of light.
Moreover, each transistor can works off at the expense of very little charge so that the image redrawing is very fast and the screen refreshes many times in a second. In a standard TFT Monitor around 1.3 million pixels with 1.3 million thin film transistors are present. These transistors are highly sensitive to voltage fluctuations and mechanical stress and will be damaged easily leading to the formation of Dots of colors . These dots without the image are called as Dead pixels. In the Dead pixels, the transistors are damaged and cannot work properly.
The Monitors using TFT are known as TFT-LCD monitors. The display of TFT monitor has two Glass substrates enclosing a layer of liquid crystal. The Front glass substrate has a color filter. The Back glass filter contains the thin transistors arranged in columns and rows. Behind the Back glass substrate, there is Back light unit that gives light. When the TFT display is charged, the molecules in the liquid crystal layer bend and allow the passage of light. This creates a pixel. The color filter present in the Front glass substrate gives the required color to each pixel.
How it differ from OLED:
Organic Electro Luminescent Display (OELD) is the recently evolved solid state semiconductor LED having a thickness of 100-500 nanometers. It is also called as Organic LED or OLED. It finds many applications including the displays in mobile phones, digital camera etc. The advantage of OELD is that it is much thinner than the LCD and consumes less power.
OLED is composed of aggregates of Amorphous and Crystalline molecules which are arranged in an irregular pattern. The structure has many thin layers of organic material. When current passes through these thin layers, light will be emitted through the process of Electrophosphorescence. The display can emit colors like Red, Green, Blue, White etc.
Based on the construction, OLED can be classified into
- Transparent OLED- All layers are transparent.
- Top emitting OLED – Its Substrate layer may be either reflective or non reflective.
- White OLED – It emits only White light and makes large lighting systems.
- Foldable OLED – Ideal to make Cell phone display since it is flexible and foldable.
- Active Matrix OLED – The Anode is a transistor layer to control the pixel. All the other layers are similar to the typical OLED.
- Passive OLED – Here the external circuitry determines its pixel formation