In this section, we shall discuss the three Computer Display Technologies currently in vogue. The technologies are;

1. TFT-LCD Technology

2. BrightView/ VibrantView/ TruLife Technology

3. AMOLED Technology

TFT-LCD Technology:

The earliest among existing Computer Display technologies is the TFT-LCD (Thin Film Transistor - Liquid Crystal) Display, commonly referred to as TFT Technology. Older Notebooks and Desktop LCD Monitors use the TFT Technology.

The Thin Film Transistor is a special kind of field-effect transistor made by depositing thin films of a semiconductor active layer as well as the dielectric layer and metallic contacts over a supporting substrate. Glass is the most common substrate, since the primary application of TFTs is in liquid crystal displays.

In comparison with the other screen technologies, TFT does not allow very good vision in daylight. However, it does not reflect glare, therefore it is less of a strain on the eyes.

Again, although TFT offers less brightness in comparison with other technologies, it also offers more realistic colors.

TFT Technology consumes maximum power. Thus, it is a good choice for Desktop LCD Monitors, where electric supply is drawn from the mains.

Notebooks using TFT-LCD technology do not give more than 3 to 4 hours, working off the Notebook's Batteries. The batteries of Notebooks using the two other display technologies last longer.

TFT Screens are a little more susceptible to sharp points as they are 'plasticky', rather than like glass, which has a hard surface.

In terms of longevity, all the technologies are about even.

BrightView/ VibrantView/ TruLife Technology:

hp and Compaq (Compaq was purchased by hp, but hp has retained the Compaq range of Notebooks and sells both brands) call their display technology BrightView, IBM and Lenovo (Lenovo acquired IBM Desktops and Notebooks and now sell all Notebooks under the Lenovo brand name) call theirs VibrantView, while Dell calls theirs TruLife. These are all the same technology, with the vendors using different terms for their display technologies. These technologies allow significantly brighter screens, thus improving daylight vision. These are therefore quite well-suited for Mobile Phones, where the user is outdoors, more often than not!

On the flip side, their color reproduction is not as life-like as TFT displays. Professional DTP personnel therefore tend to shun them. In fact, a recent online poll conducted by Lenovo showed that 86% respondents prefer the older TFT technology for these reasons!

Again, BrightView/ VibrantView/ TruLife displays tend to reflect light, thus causing glare. On tiny Mobile Phone screens, this glare is not too conspicuous. However it may become rather irritating with the larger screens that Notebooks are equipped with. Therefore, the position of the lights in the room you are working in is a lot more important, if your Computer has a BrightView/ VibrantView/ TruLife display!

BrightView/ VibrantView/ TruLife displays consume about the same amount of power as TFT-LCD displays.

BrightView/ VibrantView/ TruLife display technologies have a significantly harder surface. Therefore, they are a little less susceptible to damage from a sharpened pencil point. However, the relative hardness also makes them more brittle and hence they are more likely to shatter during a fall or crash.

AMOLED Technology:

Active Matrix Organic Light Emitting Diode (AMOLED) is the latest display technology. OLED refers to a specific type of ultra-thin, ultra-bright display technology that does not require Backlighting - something that both TFT as well as BrightView/ VibrantView/ TruLife requires. Active Matrix refers to the technology behind the addressing of pixels.

An AMOLED display consists of OLED pixels that are integrated onto a Thin Film Transistor (TFT) array, to form a matrix of pixels. The matrix generates light, when activated electrically, thus producing clear, sharp and true-to-life-colors. Typically, current flow is controlled by at least two TFTs at each pixel - one to start up and stop the charging of a storage capacitor and the second to provide a constant voltage source at the level required to create a constant current to the pixel. This arrangement eliminates the need for very high currents that are required for Passive Matrix OLED operations.

Active Matrix OLED displays provide higher refresh rate than their Passive Matrix OLED counterparts. They also consume significantly less power and therefore are best suited for portable electronic gadgets, where power consumption is critical to battery life.

The amount of power the display consumes varies significantly depending on the color and brightness shown. For example, a commercial QVGA OLED display consumes 3 Watts while showing black text on a white background and a mere 0.7 Watts when displaying white text on a black background!

Notebooks using AMOLED display technologies are now available in the marketplace. Battery charge-discharge cycle time for AMOLED display Notebooks is currently at 8 to 9 hours, as compared with the 3 to 4 hours you get on the older Notebooks with TFT-LCD and BrightView/ VibrantView/ TruLife displays. Although AMOLED  displays are priced higher than TFT or BrightView/ VibrantView/ TruLife, they are likely to become cheaper in future.

Advantages of AMOLED:

AMOLED displays fabricated on flexible plastic substrates have the following advantages:

• Thin, lightweight and rugged

• Lower power consumption, superior image quality and low cost compared to LCD technology

• Rollable display to tuck away when not in use

Backlight is a form of illumination used in Liquid Crystal Displays (LCDs). Backlights illuminate the LCD from the side or back of the display panel. These are required in small displays to increase readability in low light conditions, and in computer displays and LCD televisions to produce light in a manner similar to a CRT display. As a result, Backlights consume more battery power. Modern LCD screens consist of several layers. The backlight is usually the first layer from the back. However, in order to create screen images, it is necessary to regulate the light intensity of the screen's pixels. The most common method of regulating light is by the use of Polarizing Filters that polarize light from the source in one of two transverse directions and then pass it through a switching Polarizing Filter, to block the path of undesirable light.