Hardware Reference
In-Depth Information
over 1000:1 offer little perceptible visual difference. A good combination of both bright-
ness and contrast is a brightness rating of 300 nits (or more) along with a static contrast
ratio of 1000:1.
Note
When you evaluate an LCD TV monitor, be sure to note the brightness settings available in
computermodeandTVmode.ManyofthesedisplaysprovideabrighterpictureinTVmode
than in computer mode.
Display Power Management Signaling
Monitors, like virtually all power-consuming computer devices, have been designed to
save energy wherever and whenever possible. Virtually all monitors sold in recent years
have earned the Environmental Protection Agency's Energy Star logo by reducing their
current draw down to 15 watts (CRTs) or 5 watts (LCDs) or less when idle. Power-man-
agement features in the monitor, as well as controls provided in the system BIOS and in
the latest versions of Windows, help monitors and other types of computing devices use
less power.
For more information about power management,
see
Chapter 18
,
“
Power Supplies
,
”
p.
833
.
Display Power-Management Signaling (DPMS) is a VESA specification that defines the
signals a computer sends to a monitor to indicate idle times. The OS normally decides
when to send these signals, depending on how you have set up the power management
settings.
Table 12.19
shows the various signal states and relative power consumption according to
the DPMS state selected. Normally the monitor is placed in Suspend mode after a period
of inactivity specified in the OS power management settings.
Table 12.19 Display Power Management Signaling States
Virtually all CRT monitors with power management features meet the requirements of
the United States EPA's Energy Star labeling program, which requires that monitor power
usage be reduced from up to 100 watts or more (when operating normally) to 15 watts
