Display devices and printer What is Display Device ? Classification of Display Devices

1. VARIOUS DISPLAY DEVICES
AND PRINTERS
By:- SUMEET PATEL
Enroll. No. :- 110050111040
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2. Contents
 What is Display Device ?
 Classification of Display Devices
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3. Display Devices
 A display device is an output device for presentation
of information in visual.
 When the input information is supplied as an electrical
signal, the display is called an electronic display.
 A display device visually conveys text, graphics, and
video information.
 Common applications for electronic visual
displays are televisions or computer monitors.
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4. Classification
1. Analog display devices (cathode-ray tubes)
• Oscilloscope tubes
• TV CRTs
2. Digital display devices
• LED (including OLED) displays
• VF (vacuum fluorescent ) displays
• LCD (liquid crystal) displays
• Nixie tube displays and PDPs (plasma display panels)
• Electroluminescent displays (ELDs)
3. Others:
• Electronic paper or E paper
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5. Analog display devices -
cathode-ray tubes
A cathode ray tube (CRT) contains four basic parts:
● Electron gun
● Focusing and accelerating systems
● Deflecting systems
● Evacuated glass envelope with a
phosphorescent screen that glows visibly when
struck by the electron beam.
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6. Cathode-ray tubes
● An electron gun consists of a series of
electrodes producing a narrow beam of high-velocity
electrons.
● Electrons are released from the indirectly heated
cathode.
● The intensity of the beam is controlled by
variation of the negative potential of the
cylindrical control grid surrounding the cathode.
This electrode is called the modulator.
● The control grid has a hole in the front to allow
passage of the electron beam.
● The electrons are accelerated and focused.
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7. Examples of CRT Devices
CRT TELEVISION CRT MONITOR
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8. Digital display devices: LED
 Light emitting diodes are used in LED displays.
 Operation of the LED displays is based on the injection
luminescence.
 LED displays are available in many different sizes and
shapes.
 Usually LED displays radiate red, orange, yellow or
green light.
 They have a wide operating temperature range, are
inexpensive, easily interfaced to digital logic, easily
multiplexed, do not require high voltages and have fast
response time.
 The viewing angle is good and display of arbitrary
numbers of digits is easily assembled.
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9. Examples of LED display
LED MONITOR
LED DISPLAY
LED MATRIX
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10. Vacuum fluorescent displays
 Vacuum fluorescent displays are variation on the
triode vacuum tube. The filament of thin, oxide-coated
tungsten is heated enough to emit electrons.
 When this emitted electrons strike the phosphor on
the anode, light is produced.
 Some displays can show only digits or alphanumeric
characters. They are called segment displays,
because they are composed of several segments that
switch on and off.
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11. VACUUM FLUORESCENT DISPLAYS
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12. Liquid crystal displays
 LCD are digital passive displays characterised by very
low power consumption and good contrast with
characteristics such a scattering and reflective
configuration.
 The heart of all liquid crystal displays (LCDs) is a liquid
crystal itself. A liquid crystal is a substance that flows
like a liquid, but its molecules orient themselves in the
manner of a crystal.
 Two liquid crystal materials which are important in
display technology are NEMATIC and CHOLESTERIC
.
 Basically LCD comprises of thin layer of nematic liquid
crystal (NLC) fluid, sandwiched between two glass
plates having electrodes, at least one of which is
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13. Nixie tube displays and PDPs (plasma
display panels)
 A nixie tube is an electronic device for displaying
numerals or other information, in the form of a glass
tube containing multiple cathodes and a wire mesh
anode, filled with neon and often a little mercury and/or
argon at a small fraction of atmospheric pressure.
 When electrons in tube collide with gas atoms they
transfer this energy to the atoms, thereby exciting them
into energy levels above the ground state. The atoms
may then lose energy and return to the ground state.
Then the gas emits orange-red light. The ionised gas is
called plasma and gas displays are therefore often
called plasma displays
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14. Electroluminescent displays (ELDs)
 The electroluminescent display is similar in idea to an
ac plasma display, except that the gas-filled area is
replaced by a thin film of electroluminescent material or
Phosphor powder.
 When sufficiently large ac voltage (typically 150 to
200 V) is applied between the front and rear electrodes,
the material between them emits light.
 The advantages of ELDs include very slim
constructions, high resolution, wide operating
temperature range, and moderate power consumption.
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15. Electronic paper / e- paper
 Electronic paper, also sometimes called e-paper or
electronic ink, is a display technology designed to
mimic the appearance of regular ink on paper.
 Electronic paper reflects light like ordinary paper and is
capable of holding text and images indefinitely without
drawing electricity, while allowing the image to be
changed later.
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16. PRINTERS
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17. What is PRINTER ?
 A printer is an output device that produces text and
graphics on paper.
 Many printers are primarily used as local peripherals,
and are attached by a printer cable or a USB cable to a
computer which serves as a document source.
 Printers are classified into following types...
1. Impact and non impact printer.
2. Fully formed character and dot matrix
printer.
3. Character at a time and line at a time
printer.
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18. 1. Impact and Non impact printers.
● Impact printers form character on paper by striking
paper with a print head and squeezing inked ribbon
between print head and paper.
● Non impact printers form characters without
engaging the print mechanism with the print surface.
2. Fully formed character and dot matrix printer.
● In fully formed printers characters are embossed in
reverse on the type bars of typewriter. When printed,
all type elements appear connected or fully formed.
● Dot matrix characters are shaped by combinations of
dots that form a group representing a letter or
number viewed together.
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19. 3. Character at a time and line at a time printer.
● Character at time printers print each character
serially and instantly.
● Line at a time printers print each line virtually
instantaneously.
 Other types of printers are as follow.
● Dye sublimation printer
● All in one printer
● Photo printer
● Laser printer
● Inkjet printers etc.
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20. LINE PRINTER
LASER PRINTER
DOTMATRIX PRINTER
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21. BIBLIOGRAPHY
● Electronic Instrumentation - H S KALSI
● www.google.co.in
● en.wikipedia.org
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22. ANY QUESTIONS ???
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23. THANK YOU
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