CompTIA A+® Certification All-In-One For Dummies®, 2nd Edition

7.4. Learning about LCD Panels

Liquid crystal display (LCD), a popular display type found in laptops for many years, is now a popular choice for desktop computers and TV display. LCDs also are popular on watches and other electrical devices.

An LCD has two sheets of material, surrounding a liquid that contains crystals that act as pixels for the display. Each crystal has a red, green, and blue cell that is illuminated by an electrical charge hitting the crystal, which then creates the image you see onscreen.

The two major types of LCDs are monochrome and color. The two subtypes of color LCD displays are active matrix and passive matrix.

• Monochrome: The original LCDs were single-color displays that showed blue or dark gray on a light gray background.

• Color: The two forms of color display are active matrix and passive matrix:

  • Active matrix: An active matrix display, the most popular type of display today, uses at least one transistor per pixel, or crystal, which allows the electrical charge to be held longer on the crystal. This helps to create very crisp images with high resolution. With active matrix displays, the images are clear and easy to view, even from an angle. Because it uses transistors, an active matrix display uses more power than a passive matrix display. Active matrix displays are also known as thin-film transistor (TFT) displays.

  • Passive matrix: A passive matrix display has one transistor for each vertical column of the display and one for each horizontal row of the ...