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Transcript of A monitor or display is an electronic visual display for computers. The monitor consists of : o the...
COMPUTER SCREENS
Prepared By : Mohamed K. Mustafa
Introduced To : Mr. Ahmed Abu Mosameh
COMPUTER MONITOR
A monitor or display is an electronic visual
display for computers.
The monitor consists of :
o the display device
o circuitry
o enclosure
The display device in modern monitors is a Thin
film transistor - liquid crystal display (TFT-LCD)
. Older monitors use a cathode ray tube
(CRT).
SCREEN SIZE
The size of a rectangular display is usually
given as the distance between two opposite
screen corners, that is, the diagonal of the
rectangle.
The diagonal measurement of the rectangle is
equal to the diameter of the tube's face.
This method continued even when cathode ray
tubes {CRT} were manufactured as rounded
rectangles.
SCREEN SIZE
An example to show how the screen size can be calculated
PERFORMANCE MEASUREMENTS
The performance of a monitor is measured by the following :
1. Luminance is measured in candelas per square meter.
2. Viewable image size is measured diagonally. For CRTs, the
viewable size is 1 in (25 mm) smaller than the tube
itself.
3. Aspect ratios is the ratio of the horizontal length to the
vertical length. 4:3 is the standard aspect ratio
4. Display resolution is the number of distinct pixels in each
dimension that can be displayed.
5. Dot pitch is the distance between subpixels of the same
color in millimeters.
PERFORMANCE MEASUREMENTS
6. Refresh rate is the number of times in a second that a
display is illuminated.
7. Response time is the time a pixel in a monitor takes to go
from active (black) to inactive (white) and back to active
(black) again.
8. Contrast ratio is the ratio of the luminosity of the brightest
color (white) to that of the darkest color (black) that the
monitor produced.
9. Power consumption is measured in watts.
10. Viewing angle is the maximum angle at which images on the
monitor can be viewed, without distortion .
COMPARISON ‘ CRT ’
Adv.
• High dynamic range , excellent
color , low black level .
• No input lag
• Sub-millisecond response times
• Near zero color, saturation, contrast
or brightness distortion. Excellent
viewing angle.
• Usually much cheaper than LCD or
Plasma screens.
Disadv.
• Large size and weight
• High power consumption
• Geometric distortion
• Older CRTs are prone to screen burn-
in
• Produces flickers at low refresh
rates
CRT MOINTORS
COMPARISON ‘ LCD ’
Adv.• Very compact and light
• Low power consumption
• No geometric distortion
• Rugged
• Little or no flicker
Disadv.
• Limited viewing angle, causing color,
saturation, contrast and brightness
to vary , causing some distortion • Slow response times• Input lag • Dead pixels may occur during
manufacturing or through use.
LCD MOINTORS
COMPARISON ‘ PLASMA’
Adv.
• Compact and light.
• High contrast ratios excellent color,
low black level.
• High speed response.
• Near zero color, saturation, contrast or
brightness distortion
• No geometric distortion.
• Highly scalable, with less weight gain
per increase in size
Disadv.
• Large pixel pitch, meaning large screen.
• Flickers when viewed at close range
• High operating temperature and power
consumption
• Fixed bit depth
• Input lag
• Older ones may burn-in
• Dead pixels are possible during
manufacturing
PLASMA MOINTORS
PROBLEMS
o Phosphor burn-in
In older screens the phosphor layer of a CRT screen where it has
displayed a static bright image for many years. This results in a
faint permanent image 3:4 on the screen , even when turned off.
o Plasma burn-in
Burn-in is existing with early plasma displays , which are more
week to this than CRTs.
Screen savers with moving images may be used with these to
minimize burn.
PROBLEMS
o Glare
Glare is a problem caused by the relationship between lighting
and screen, or by using monitors in bright sunlight
o Color mis-registration
Most LCD screens , have mis-registration of the color channels,
that is, the centers of the red, green , and blue dots do not
line up perfectly.
o Incomplete spectrum
RGB [registered] displays produce most of the visible color
spectrum, but not all. This can be a problem .
MONITORS USAGE
o Multiple monitors
More than one monitor can be attached to the same device. To
show the same image or each monitor can display a different
image.
o Multiple video sources
Multiple devices can be connected to the same monitor using a
video switch. It is designed to switch all of the user interface
devices for a workstation between different computers at once.
o Virtual displays
Much software and video hardware supports the ability to create
additional, virtual pieces of desktop, commonly known as
workspaces.
ADDITIONAL FEATURES
o Power saving Most modern monitors will switch to a power-saving mode.
This allows modern operating systems to turn off a monitor after a specified period
o Integrated accessories Many monitors have other accessories integrated. So no need
for another separate , camera , microphone , and speakers.o Glossy screen Some displays replace the traditional anti-glare matte finish
with a glossy one. The image is better . o Directional screen Narrow viewing angle screens are used in some security
applications .
ADDITIONAL FEATURES
o Auto polyscopic screen A directional screen which generates 3D images .
o Touch screen These monitors use touching of the screen as an input
method. Items can be selected or moved with a finger .
o Tablet screens A combination of a monitor with a graphics tablet. Such
devices are typically unresponsive to touch without the use of one or more special tools' pressure.
THANK YOU