Input, Output, and Storage - Computing Fundamentals - page 54

through the second filter and lights up the display in a certain spot.
Color displays have separate filters for red, green, and blue. Some new
mobile devices use organic light-emitting diode (OLED) technology,
which uses organic matter that lights up in response to an electrical
current.

organic light-emitting diode (OLED) A flat-
screen technology that uses organic matter that
lights up in response to electrical current to create
a display image.

© iStockphoto.com/dem10
Figure.3 16 An LCD monitor has a thin, flat screen.

Flat-screen displays vary in the number of transistors used to create the
display image. In an active matrix , each individual pixel in the display is
actively maintained by a separate transistor. Almost all LED screens today are
an improved variant of an active matrix called thin-film transistor (TFT) .
In a passive matrix (which is cheaper to manufacture), each pixel maintains
its state on its own until it decays or is refreshed. An OLED screen may be
active matrix or passive matrix, depending on the model.

active matrix An LCD type in which each pixel
is actively maintained by a separate transistor.

thin-film transistor An improved type of active
matrix common in modern monitors and display
screens.

passive matrix An LCD type in which each pixel
maintains its state on its own until it decays or is
refreshed.

A high-definition TV (HDTV) can also be used as a computer monitor by connecting the computer to one of its
high-definition multimedia interface (HDMI) input ports.

NOTE

high-definition TV (HDTV) A television that
displays at least 1920 × 1080 resolution (also
known as 1080p).

Cathode ray tube (CRT) is an older monitor technology that uses
a large vacuum tube and electron guns to create a display image on a
phosphor-covered glass. See Figure 3.17. The electrons strike phosphors
on the monitor glass and briefly light up. The display is refreshed many
times per second to maintain the image. The phosphors are arranged in
triads : red, green, and blue, as shown in Figure 3.18. Depending on what
color a particular pixel should be, different phosphors illuminate within
that triad. CRT monitors are heavy and bulky compared to LCDs, and
have mostly been replaced by LCD monitors. You may still see one in use
with an older computer, however.

high-definition multimedia interface
(HDMI) A type of connector used to connect an
HDTV to another device, such as a computer or a
home theater system.

cathode ray tube (CRT) An older type of
monitor technology that uses a vacuum tube and
electron guns to create a display image.

triad A cluster of three phosphors: one red, one
green, and one blue.