Datasheet

Display Devices

Digital Video Interface (DVI) There are several types of DVI pin conﬁgurations, but all

connectors are D-shaped. The wiring differs based on whether the connector is single-linked

or dual-linked (extra pins are used for the dual link). DVI differs from everything else in that

it includes both digital and analog signals at the same time, which makes it popular for LCD

and plasma TVs. Figure 1.19 shows a DVI connector.

FIGURE 1.19 One of several possible DVI connectors

High Definition Multimedia Interface (HDMi) These connectors are used to connect

compatible digital items (DVD players, for example). The Type A connector has 19 pins

and is backward compatible with DVI. Type B connectors have 29 pins and aren’t back-

ward compatible with DVI, but they support greater resolutions.

S-Video The S-Video connector looks much like a PS/2 connector, except that it has four

conductors. These are also known as Y/C connectors; they break the signal into two com-

ponents (luminance and chrominance) instead of carrying them in a single signal.

Component/RGB Component connectors are similar to what you use to connect video

recorders and other items to televisions. They have RCA jacks and use red, green, and

blue signals.

Liquid Crystal Displays

Two major types of LCDs are used in laptops today: active matrix screens and passive

matrix screens. Their main differences lie in the quality of the image. Both types use some

kind of lighting behind the LCD panel to make the screen easier to view.

Passive Matrix A passive matrix screen uses a row of transistors across the top of the screen

and a column of them down the side. It sends pulses to each pixel at the intersections of each

row and column combination, telling it what to display.

Passive matrix displays are becoming obsolete because they’re less bright and have poorer

refresh rates and image quality than active matrix displays. However, they use less power

than active matrix displays do.

Active Matrix An active matrix screen uses a separate transistor for each individual

pixel in the display, resulting in higher refresh rates and brighter display quality. These

screens use more power, however, because of the increased number of transistors that

must be powered. Almost all notebook PCs today use active matrix. A variant called

thin-ﬁlm transistor (TFT) uses multiple transistors per pixel, resulting in even better dis-

play quality.

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