2. Cathode Ray Tube (CRT)
VERTICAL
ELECTRON PHOSPHOR
DEFLECTION
GUN COATED
FOCUSING PLATES
SCREEN
BASE SYSTEM
HORIZONTAL
CONNECTOR
DEFLECTION
PINS ELECTRON
PLATES
BEAM
3. RESOLUTION
• The maximum number of points that can
be displayed without overlap on a CRT.
• The number of points per centimeter that
can be plotted horizontally and vertically.
4. PLASMA PANELS
• Also called gas-discharge displays.
• Constructed by filling the regions between
two glass plates with a mixture of gases
that usually includes neon.
• Firing applied to a pair of horizontal and
vertical conductors cause the gas at the
intersection of the two conductors to break
down into a glowing plasma of electrons
and ions.
7. Liquid Crystal Display (LCD)
• These produce picture by passing polarized light
from the surroundings or from the internal light
source through a liquid-crystal material that can
be alligned to either transmit or block the light.
• The main principle behind liquid crystal molecules is
that when an electric current is applied to them, they
tend to untwist. This causes a change in the light
angle passing through them. This causes a change
in the angle of the top polarizing filter with respect to
it. So little light is allowed to pass through that
particular area of LCD. Thus that area becomes
darker comparing to others.
8.
9.
10.
11. LASER PRINTER
• It uses a very fine powder known as ‘Toner’.
• The photoconducting drum which is the key component of the laser printer
has a special coating which receives the positive and negative charge from
a charging roller.
• A rapidly switching laser beam scans the charged drum line by line. When
the beam flashes on, it reverses the charge of tiny spots on the
drum, respecting to the dots that are to be printed black.
• As soon the laser scans a line, a stepper motor moves the drum in order to
scan the next line by the laser.
• A developer roller is coated with charged tonner particles. As the drum
touches the developer roller, the charged tonner particles cling to the
discharged areas of the drum, reproducing your images and text reversely.
• As the paper passes through a charging wire it applies a charge on it
opposite to the toner’s charge.
• When the paper meets the drum, due to the opposite charge between the
paper and toner particles, the toner particles are transferred to the paper.
12.
13. INK-JET PRINTERS
• At the heart of an ink jet printer are a large number of
high-precision microscopic nozzles which eject ink onto
the paper.
• The ink jet nozzles are all mounted together on a moving
carriage assembly that moves at high speed back and
forth across the paper.
• Ink drops are commonly printed at a resolution of 600 or
1200 dots per inch.
• Optical encoders precisely control the location of the
printed dots, both across and down the page.
