Display types (LED, LCD, Plasma, Plotter, Virtual Reality)

This is one of my assignments which I did in the University. This is about display types with small descriptions.

1. GRAPHICS AND IMAGE PROCESSING
ICT 2403
RAVI YASAS JAYASUNDRA
ICT /10/11/013

ASSIGNMENT #1

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Plasma panel display

Overview
 This is a flat panel display consist of two glass panels each with parallel electrodes
deposited on their surface.
 Electrodes covered with a dielectric layer.
 The long electrodes are stripes of electrically conducting material that also lie
between the glass plates, in front of and behind the cells.
 As can be seen in the illustration, the electrodes are covered by an insulating
protective layer.
 The transparent display electrodes are mounted in front of the cell, along the front
glass plate.
 Control circuitry charges the electrodes that cross paths at a cell, creating a voltage
difference between front and back.
 The "address electrodes" sit behind the cells, along the rear glass plate, and can be
opaque.
 To erase a cell all voltage is removed from a pair of electrodes.
 With flow of electricity (electrons), some of the electrons strike mercury particles as
the electrons move through the plasma, momentarily increasing the energy level of
the molecule until the excess energy is shed.

Advantages
 It has a high contrast ratio because it is used over 16 million colors.
 Can be used for large screen sizes.
 This type of display has 160 degree viewing angle.
 It is very thin than CRT display.

Disadvantages
 Does not perform well at high altitudes above 2km.
 Uses more power than LCDs.
 Has shorter lifespan than LCDs.
 More expensive

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Liquid Crystal Display (LCD)

Overview
 This is used light modulating properties of liquid crystals.
 This is made of two sheets of a flexible polarizing material with a layer of liquid
crystal solution.
 This type of display does not refresh like CRT.
 An electric current passed through the liquid causes the crystals to align so that
light cannot pass through them.
 Each crystal, therefore, is like a shutter, either allowing light to pass through or
blocking the light.


Advantages
 Very thin, compact and light weight.
 Very low power consumption.
 No geometric distortion at the native resolution.
 Can be created small and large size of displays with high resolutions (Theoretically
no limit).
 Images are perfectly sharp and produce very bright images due to high peak
intensity.

Disadvantages
 Low refresh rate
 Slow response times.
 Limited viewing angle.
 The aspect ratio and resolution are fixed.
 Low contrast than CRT due to a poor black level.

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LED Backlit Display

Overview
 These types of displays use LED as a light resource.
 These type of displays are not self-illuminating.
 There are few types of Backlit LED displays.
1. RGB LED backlighting
2. An edge backlight with white LEDs
3. A flat backlight based on white LEDs.


Advantages
 It gives better dynamic contrast.
 Have a long lifespan.
 Uses less power.
 Extremely thin (less than 0.5inch displays are available).
 It has fast response.


Disadvantages
 This types of displays are more expensive.

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Plotter

Overview
 Plotter is a printer that is used to print vector graphics.
 This is not like a simple printer, it is used automated pens to draw.
 There are different types of plotters.

1. Drum plotter
2. Flatbed plotter
3. Electrostatic plotter

 Now a days there are cutting plotters also in the market which can be used to print
and cut.
 HP is the leading plotter vendor in the world.
 This is widely used to draw in engineering field like to CAD and CAM.

Advantages
 Can be used to large size of printings like posters, banners etc.
 Can print not only simple papers but also hard papers like weather resistance
papers.
 Have a good contrast than normal printers.

Disadvantages
 Plotters are very expensive than printers.
 It gets lot of time to print.
 Printing materials are expensive.

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Head Mounted Display

Overview
 This is a simple helmet which includes display with lenses and semitransparent
mirrors.
 Real pictures or pictures generated by a computer can be seen through this device.
 Modern HMD devices are come with LCD display. Because this should be light
weighted and compact.
 Very rarely it comes with other display technologies like LED, EPD (Electrophoretic
Displays), VRD (Virtual Retinal Displays), and Plasma etc.
 Many of these HMD devices come with integrated speakers or headphones.
 HMDs widely used in video games, simulators, military purposes, medicine and
engineering areas.

Advantages
 It can make a better simulation environment than other equipment.
 Even when you are on the bed, you can wear this. It need not a relevant position to
wear.
 It is easy to handle because of its compactness.

Disadvantages
 It may be caused to headache and your eyes can be harmed when you use it a long
time.
 These devices are expensive.

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Virtual reality

Overview
 This is the way that you can get a real experience of hard situations without any
harm.
 In this technology use HMD (Head Mounted Display) which is giving a 3D images.
 User can get the simulating experience using sound, images and videos.
 Now a days there is a device called ‘Haptic Device’ to get the further experience of
touch and force feedback enabled environment.
 This technology is developed by scientists and computer programmers.


Advantages
 Can be create 3D situations.
 Can be used for simulating purposes
1. To train doctors
2. To get the real experience of gaming
3. To train soldiers using battle situations.


Disadvantages
 This is high costly technology.
 It is hard to use in home.