Whats difference between an LCD & LED,its confusing many time,therefore for better understanding,i make it.

1. LED & LCD
ELECTRONICS AND COMMUNICATION ENGINEERING
POORNIMA INSTITUTE OF ENGINEERING & TECNOLOGY,
JAIPUR
A PRESENTATION ON
SUPERVISED BY:
Mr. Rahul Gupta
Assistant Professor
SUBMITTED BY:
-Madhusudhan
Agarwal

2. What is LED?
 A light emitting diode (LED) is essentially a PN junction
opto-semiconductor device.
 It emits a monochromatic (single color) light when
operated in a forward biased direction.
 LEDs convert electrical energy into light energy.

3. How Does An Work?
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a. When sufficient voltage is applied to
the chip across the leads of the LED,
electrons can move easily in only one
direction across the junction between
the p and n regions.
 When a voltage is applied and the
current starts to flow, electrons in the
n region have sufficient energy to move
across the junction into the p region.

4. How Does A LED Work?
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1.Each time an electron recombines with a
positive charge, electric potential energy is
converted into electromagnetic energy.
2.For each recombination of a negative and a
positive charge, a quantum of electromagnetic
energy is emitted in the form of a photon of
light with a frequency characteristic of the
semi-conductor material (usually a
combination of the chemical elements gallium,
arsenic and phosphorus)..

5. Inside a Light Emitting Diode
1. Transparent
Plastic
Case
2. Terminal
Pins
3. Diode

6. Driving LEDs
Two type of DRIVING LED
 Analog LED Drive Circuits
 Digital LED Drive Circuits
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7. Analog LED Drive Circuit
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8. Digital LED Drive Circuits
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9. Bargraph 7-segment Starburst Dot matrix
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Some Types of LEDs

10. Advantage of an LED
 Efficiency is high
 Small size
 On/Off time is less .
 Slow failure
 Lifetime

11. Applications of an
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• Sensor Applications
• Mobile Applications
• Sign Applications
• Automative Uses
• LED Signals
• Indicators

12. Liquid-Crystal (LCD) Displays

13. 1. What’s Liquid Crystals (LC)
 intermediary substance between a liquid and solid state
of matter.
e.g. soapy water
 light passes through liquid crystal changes when it is
stimulated by an electrical charge.
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14. 2. Introduction to Liquid Crystal Displays
 A liquid-crystal display (LCD) is a flat panel display
that uses the light modulating properties of liquid
crystals.
 Liquid crystals do not emit light directly
 It consists of an array of tiny segments (called pixels)
that can be manipulated to present information
 Using polarization of lights to display objects
 Common wrist watch and pocket calculator to an
advanced VGA(video graphic array) computer screen
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15. Different types of LCDs
There are Two type of LCDs available
1.Passive Matrix LCDs
2.Active Matrix LCDs
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16. Active Matrix V/S Passive Matrix LCDs
Active Matrix LCD
 Allow very high resolution
 It isn`t limited to about 50 rows
 Each sub-pixel is individually
controlled by an isolated thin-
film transistor (TFT).
 More use in Laptop & TV
Passive Matrix LCD
 Allow high resolution
 It is usually limited to about 50
rows
 Each sub-pixel is not individually
controlled by an isolated thin-
film transistor (TFT).
 Less use in Laptop & TV

17. LCD Display Technology
Technology Enhancements:
Better color through corrected CCFLs, LEDs
Improved black levels (compensating films)
Higher contrast (pulsed backlights)
Wider viewing angles (compensating films)
Higher resolution (1920x1080)
Improved LC twist times

18. Advantages
 Very compact and light.
 Low power consumption.
 Very little heat emitted during operation, due to low power consumption.
 No geometric distortion.
 Is very thin compared to a CRT monitor, which allows the monitor to be
placed farther back from the user, reducing close-focusing related eye-
strain.
 Can be made in almost any size or shape.
 No theoretical resolution limit.
 Can be made to large sizes (more than 24 inches) lightly and relatively
inexpensively.
.

19. Applications
 Thin Film Transistor (TFT)
 Alpha-numeric display
 Back lighting systems
 For brighter displays

20. Comparison Between LED & LCD
LED
 Power Consumption is less
 Faster response rate time
 Sizes Available
17inches and 70inches.
 Color Accuracy is less
 Cannot be extremely slim
LCD
 Power Consumption is more
 Slower response rate time
 Sizes Available
15inches to 65 inches
 Color Accuracy is more
 Can be extremely slim

21. AND

22. THANKYOUFOR YOUR
PATIENCE….