Active-Matrix Displays

Active-matrix displays are also known as TFTs (thin film transistors). They differ from dual-scan screens because they have a transistor for every pixel on the screen rather than just at the edges. Electrodes apply voltages at the perimeter of the grid to address each pixel individually.

Because each pixel is powered individually, generating its own light and the appropriate color, a much brighter and more vivid picture results. Creating light instead of altering reflection provides a wider viewing angle, which allows more than one viewer to see the screen at a time. The refreshes are faster and the display lacks the fuzziness associated with the dual-scan systems.

Naturally, the cost of having 480,000 transistors instead of merely 1400 (on an 800 × 600 screen) makes the active-matrix screen more expensive. It also requires a lot more power and drains batteries faster. Failure of a transistor causes individual "dead pixels," but this is far less noticeable than the black line caused by a transistor failure of the dual-scan screen.

Larger screens and higher resolutions mimicking that of desktop models have become the standard on high-end laptops. Many portable systems today also include PCI (Peripheral Component Interconnect) bus video adapters. These screens come very close to the quality of a desktop display, but lack some of the fine controls available on fixed units.