FLAT PANEL Displays

First, LED, LCD, and Gas-Plasma are techniques for engineering the displays on Lap-Top or portable PCs.

The terms are:

  1. LED - Light Emitting Diode

  2. LCD - Liquid Crystal Display

  3. Gas-Plasma - Neon Gas

The primary problem with most portable computers is displaying information on a screen which is small enough to be portable. Most CRTs use serious amounts of electrical power. The batteries supplied with most LAPTOPs will not provide power to use a normal CRT, even if the weight and size was acceptable.

The three technologies listed above can be used in LAPTOPs; however, each of them present their particular advantages and disadvantages. Power consumption and its related problem of heat generation is the primary concerns. Lets look at each of them.

  1. Light Emitting Diodes - LEDs have the problem of being heavy consumers of power. To fully illuminate a screen, based on the resolution, you might need more than 100,000 LEDs to illuminate all the proposed pixels on a screen. A single LED may draw from 10 to 100 milliwatts (.001 watts). Even with the small size of an LED on a screen, they still draw much more power than is required by other technologies.

    LED monitors tend to fade in strong light, and they are expensive to fabricate, especially in larger screen sizes.

  2. Liquid Crystal Display - LCDs are the primary display technology used in LAPTOP computers. There are three types of LCDs: reflective LCDs, Backlit LCDs, and edgelit LCDs.

    While other technologies use light (energy) to display, the LCD simply block light otherwise available to them, thereby reducing energy usage.

    To make patterns visible, they may either selectively block reflected light (reflective LCDs), or use light generated by a secondary source either behing or adjacent to the LCD panel.

    The "backlight" source is usually an electroluminescent panel. Some laptops use cold-cathode floursecent (CCF) for brighter, white displays. The CCF costs more, are thicker, and more complex. An LCD color screen can easily add enough cost to double the original cost if the LED was monochrome.

  3. Gas-Plasma - This technology is the easiest to manufacture and it produces the sharpest images of the three technologies. However, it requires several times the amount of power required by a LCD screen, and at high voltages. This means you have to disperse a large amount of heat. The Gas-Plasma displays are used primarily in AC powered portables because of the difficulties of synthesizing high voltages from low-voltage batteries. A battery would have a lifecycle time of about 1 hour on a system with a gas-plasma display.
Controller Devices