MADHUBEN AND BHANUBHAI PATEL WOMEN’S INSTITUTE OF ENGINEERING FOR STUDIES AND RESEARCH IN COMPUTER AND COMMUNICATION TECHNOLOGY Presentation on: (LED TVs) Prepared as a part of the requirements for the subject of AUDIO VIDEO SYSTEM B. E. Semester – IV (E.C. Branch) BY- Soni Margi A. ( ) GUJARAT TECHNOLOGICAL UNIVERSITY (GTU)

It is nothing but light emitting diode (LED) based video display. LED TV displays are not an entirely new technology, but a variation on LCD displays. LCD TVs use cold cathode fluorescent lamp(CCFL) while LEDs use light emitting diodes. 2

 An LED TV uses less power, provides a brighter display with better contrast, a thinner panel, and lesser heat dissipation than a conventional LCD TV.  This is because an LED TV uses light-emitting diodes for backlighting as opposed to the CCFLs of conventional LCD TVs.  The display of an LED TV is not an LED display, so a more technically correct name for it would be "LED-backlit LCD television." 3

 RGB Dynamic LEDs show true blacks and whites and thus get higher dynamic contract ratio at the cost of less detail in small bright objects on a dark background.  White LEDs are less costly, while red, green and blue (RGB) LEDs provide a richer color gamut.  An LED TV offers more colors, especially ones that use RGB-LED backlighting. 4

 LED stands for light emitting diode whereas LCD stands for liquid crystal display.  LED tv uses light emitting diode, LCD tv uses cold cathode fluorescent lamp (CCFL).  While CCFL backlights typically provide white light, LED backlights may supply either white light or a mixture of red, green, and blue. 5

 LED backlights don’t require high ac voltages, LCD backlit require high ac voltage.  The difference in lights and in lighting placement has generally meant that LED TVs can be thinner than LCDs.  LED TVs are consume less power than LCD TVs.  CCFL tubes can’t be switched on or off while a display is turned on and can only be arranged in vertical or horizontal lines. This creates picture quality problems. LEDs, on the other hand, can be quickly switched on or off. This allows much better control of light. 6

Plasma TVLED TV Best for black rooms.Best for bright rooms. Good picture quality.Less picture quality than Plasma TV. Consume more space.Consume less space. Less expensive than LED TVs.Expensive than Plasma tv. It light themselves using gas cells that emit ultraviolet light. It lights the screen using light emitting diode. Heavier compared to LED-lit LCD TV.Lighter compared to plasma TV. Not as bright as LED-lit LCD.Brighter than plasma or OLED Screen size is 42 inches and above.Screen size is up to 90inches. Less energy efficient than LED TVs.More energy efficient than Plasma TVs. Manufacturer: Panasonic, LG, Samsung.Manufacturer: All TV manufacturing companies. 7

 OLED stands for organic light-emitting diode.  Both OLED and LED use the same principle of electroluminescence- the optical and electrical phenomenon where certain materials emit light in response to an electric current passing through it.  OLED  Lighter weight  Perform at lower efficiencies  Less power consumption  Organic based chemicals 8

 Composed of two substrate layers on the outside  Emissive and conductive layer lie between the cathode and the anode layers  A current is applied across the LED, where electrons move from cathode to anode  The cathode gives electrons to the emissive layer, where the anode withdraws these electrons from the conductive layer  The emissive layer becomes rich in negative charge while the conductive layer becomes more positively charged  The two charges recombine in the emissive layer, creating a drop in energy levels of the electrons  The drop in energy levels results in radiation that is on the visible spectrum, emitting light 9

 Passive-matrix OLED  Active-matrix OLED  Transparent OLED  Top-emitting OLED  Foldable OLED  White OLED 10

 Thinner, lighter and more flexible  Plastic substrates rather then glass  High resolution  Do not require backlight  Low voltage, low power and emissive source  Robust Design  Brighter- good daylight visibility  Larger viewing angles -170 o 11

 Lifetime  White, Red, Green  46, ,000 hours About 5-25 years  Blue  14,000 hours About 1.6 years  Expensive  Susceptible to water 12