Tft Display Technology

by Alba Soler Photography

TFT displays are a type of liquid crystal display (LCD) that uses the thin film transistor (TFT) technology. Most commonly used as display units for computers and TVs, TFT modules have become the new standard in viewing digital media. They contain thousands of pixels (transistors) made of a thin film silicon deposited on a glass panel. The glass panel can either be matte or glossy. Plasma-enhanced chemical vapor deposition is a process used to deposit thin films from a gas state to a solid state on a substrate. One of the best picture producing TFT displays is found on the Lenovo W700 laptop computer which boosts a 1920X1200 screen resolution, 400 brightness level and a 500:1 contrast ratio. However, not all TFT modules are the same. Resolution, brightness and contrast vary greatly depending on the technology used to create the display.

Twisted Nematic (TN) is the least expensive to make and are the most widely available. They have high response times, which are great for gamers, although they lack color reproduction. Viewing angles and contrast ratios of TN panels are the worst of any current LCD panel technology.

S-PVA/MVA panels have better color richness and viewing angles than TN panels. They also have slower response times than TN or S-IPS, offer the best contrast ratios though may suffer from color shifting or input lag.

IPS panels are generally considered the best all around panel type, except that they are more expensive and are not made in abundance.

TFT Modules incorporate two different forms of backlighting; Cold cathode fluorescent lamps (CCFL) and Light Emitting Diode (LED). CCFL light uses fluorescent lamps to light the TFT displays which has certain drawbacks most notably the power consumption and the longevity of the lamps. They require an inverter to supply power to the lamps. Laptops usually have one tube at the top and one at the bottom. In TVs, there is a series of tubes behind the TFT display. Brightness and color enhancement in LED technology are superior to the CCFL backlighting option. LED can be edge mounted or direct mounted. Direct mounted LED provide better contrast ratio and fine backlight control while edge mounted LED can be used to make screens incredibly thin. In addition to direct and edge mounted, LEDs can use either white or RGB light. Red, green and blue LEDs are capable of a broader color spectrum.

Organic Light Emitting Diode technology is the next generation of display modules. They will soon be in direct competition with TFT LCD screens as they are expected to produce an even better picture and viewing angles. The OLEDs actually produce the color, where LED backlights just provide a white light source which is then filtered through a color LCD matrix to produce the picture.