Specifications

Video Display Technologies
871
DVI—Digital Signals for CRT Monitors
The latest trend in CRT monitor design is the use of digital input signals using the same Digital Video
Interface (DVI) standard used for LCD flat-panel displays. Although several major monitor vendors
announced support for DVI-I interfaces for their CRT monitors in 1999, most CRT monitors (except
for a few 19'' or larger high-end monitors) continue to use the conventional 15-pin analog VGA
connector. CRT monitors that use the DVI-I connector—unlike the TTL digital displays of the 1980s
that supported only a few colors—support the same unlimited color spectrum as analog CRTs. Users
benefit from digital displays because these displays can feature better picture quality, better signal
reception, and precise auto setup.
Because most low-end and mid-range video cards still feature only analog (DB-15) VGA connectors,
many of these monitors feature both analog and 20-pin DVI interfaces. However, as all-digital LCD pan-
els that also use the DVI interface increase in popularity and DVI interfaces on video cards continue to
increase in popularity, analog VGA eventually might be replaced by DVI-based CRT and LCD panels.
◊◊ See “LCD Panels,” p. 871.
◊◊ See “Flat-Panel LCD Monitors,” p. 874.
LCD Panels
Borrowing technology from laptop manufacturers, most major monitor makers sell monitors with liq-
uid crystal displays (LCDs). LCDs have low-glare, completely flat screens and low power requirements
(5 watts versus nearly 100 watts for an ordinary monitor). The color quality of an active-matrix LCD
panel actually exceeds that of most CRT displays.
At this point, however, LCD screens usually are more limited in resolution than typical CRTs. Table
15.1 compares the typical resolutions of LCD monitors from 15'' to 22'' to mainstream CRT monitors
ranging from 17'' to 22'' with comparable viewable areas.
Table 15.1 LCD and CRT Resolutions Compared
LCD Size LCD Resolution CRT Size CRT Viewable Area CRT Maximum Resolution
15'' 1024×768 17'' 16'' 1024×768
1280×1024
1600×1200*
17'' 1280×1024 — — —
18.1'' 1280×1024 19'' 18'' 1600×1200
1920×1440*
19'' 1280×1024 — — —
20.1'' 1600×1200 21'' 20'' 1600×1200
1920×1440*
*Available on high-end monitors only
As you can see from Table 15.1, you need a 20.1'' or larger LCD panel to achieve resolutions above
1280×1024, although most 18'' CRT displays can achieve 1600×1200.
Despite recent price drops, LCD panels continue to be more expensive than comparably sized CRTs.
A typical 15'' LCD panel sells for around $250–$400, compared to flat-screen 17'' CRTs, which sell for
around $150–$250. However, as Table 15.1 shows, it is important to consider that an LCD screen pro-
vides a larger viewable image than a CRT monitor of the same size. See Figure 15.3 for an example of
a typical desktop LCD panel.
Chapter 15
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