12. 11.1" TFT LED Backlit Display: A Solution For The Mobility Energy Crisis?

The TX series laptops are all equipped with an 11.1" TFT display.

About thirty percent of the power in a laptop PC is used by the display and its various related subcomponents, when the unit is employed for normal office work and applications. These gory details are spelled out completely in another of our articles: Squeezing More Life Out of Your laptop's Battery Part I. To realize the longest possible battery lifetime, Sony's designers had to think through the problem very carefully.

The power consumption of a display depends on both its size and on the type and brightness of the backlighting it uses. The display size also dictates the form factor and the overall size of the laptop - that makes this parameter impossible to "fudge." In the most typical cases, cold cathode light sources deliver backlighting for displays. These devices are also known as phosphorescent lamps or Cold Cathode Fluorescent Lights (CCFLs).

One of the most important reasons for the low power consumption of an LED-backlit laptop is the markedly lower power levels required for this light source to work (Source: Sony Corporation).

This light source entails various disadvantages, though. For one thing, these devices are relatively thick and mean that it's not possible to make displays as thin as designers might like. In addition, they require a voltage converter, because they need high voltage levels (around 500 V) to work properly. A laptop battery delivers far less voltage, which makes a transformer necessary. And of course, transformers themselves also consume additional energy. In other words: simply delivering the right amount of electrical power required to make the display function consumes relatively large amounts of energy, on top of what the display itself uses.