Future Trends of Televisions

By: Rion Núñez

Team 11

Types of Televisions

CRT (cathode ray tube) Plasma LCD (liquid crystal display) DLP (digital light processing) OLED (organic light emitting diode) SED (surface-conduction electron-emitter

display)

CRT (cathode ray tube)

Invented in 1897 by Karl Ferdinand Braun

Standard for televisions until recent years

How CRT works A=cathode B=conductive coating C=anode D=phosphor-coated screen E=electron beams F=shadow mask

Uses R,G,and B phosphors The three beams are

accelerated and focused by the anode

CRT Advantages

High color fidelity and contrast

Better resolution with moving images

CRT Disadvantages

susceptible to phosphor burn-in

Bulky and heavy sets

Consume a lot of energy

Old technology

Plasma Displays

invented at the University of Illinois at Urbana-Champaign in 1964 for the PLATO Computer System

1983 IBM introduced 19” orange on black monochrome

Gas made up of free flowing ions and electrons

How Plasmas work Made up of tiny fluorescent lights Each pixel contains a red, green,

and blue light xenon and neon gas is contained in

hundreds of thousands of cells positioned between two plates of glass along with electrodes

When charged, it releases ultraviolet photons which act with the phosphors

This brings their energy level up, when it goes back down it is released as visible light photons

Plasma Advantages

Brighter than CRTs

Flat panel

Lowering in cost

Plasma Disadvantages

Susceptible to phosphor burn-in

Not well used in bright rooms

LCD (liquid crystal display)

Liquid crystals were first discovered in 1888, by Austrian botanist Friedrich Reinitzer

First experimental LCD by RCA in 1968

Based on properties of polarized light

How LCD works Formed by two glass layers called

substrates One is in charge of columns, and the

other is in charge of rows Liquid crystals are sandwiched in

between these two layers Uses a grid to charge specific pixels When this happens the crystals untwist

and allow light to pass through

LCD Advantages

More efficient use of electricity than CRT

Produce little glare compared to plasmas

Largest screen sizes than other flat panels

LCD Disadvantages

Manufacturers often reject about 40 % of the panels that come off the assembly line

Color contrast is not the best

DLP (digital light processing)

Developed by Texas instruments

Created by Dr. Larry Hornbeck in 1987

How DLP works One DLP chip contains more than 2 million

mirrors Each mirror made of aluminum represents

one pixel on the screen The chip will rapidly decode a bit-streamed

image code that enters through the semiconductor

It changes the data from interlaced to progressive scanning and adjusts the picture

The mirrors then tilt off and on to allow light to pass and can do it up to 5,000 times per second

The is then sent through a transparent, spinning color wheel that is synchronized with the chip into red, green, and blue, light, and can produce 16.7 million colors

DLP Advantages

Insusceptible to phosphor burn-in

More affordable than plasmas and LCDs

DLP Disadvantages

Not as thin as other high definition displays

OLED (organic light emitting diode)

Developed by Eastman-Kodak

Competing against LCD and plasma television displays

How OLED works Has two to three layers of organic material

the emissive and conductive layer These these are sandwiched in between

the cathode and anode When an electrical current is sent through

the LED, it moves from the cathode to anode (negative to positive)

The cathode gives electrons to the emissive layer, and the anode takes away electrons from the conductive layer

When they recombine, the extra energy is given off as light which corresponds to the type of organic molecule

The voltage also depends on how much light is given off

OLED Advantages

Thinner, lighter, more flexible Can be plastic instead of glass Does not require backlighting Brighter than traditional LED’s Consume less power than LED’s Large field of view around 170 degrees

OLED Disadvantages

Easily damaged by water

High manufacturing costs

Blue OLED films have shorter lifespan than Red and Green

SED (surface-conduction electron-emitter display)

Formed in 2004 between Toshiba and Canon

Created SED Co. LTD for developing and producing SED technology

Canon for electron source technology

Toshiba for the display

How SED works Uses millions of cathode ray tubes

called SCEs (surface-conduction electron emitters)

They have a layer of carbon with a gap down the center

Half of the carbon layer is connected to a negative electrode, the other to a positive

Activates SCEs all at once instead of CRT going one row at a time

Does not use interlacing

SED Advantages

Lower power consumption Fast video response High contrast of color 3cm thick Better picture than LCD and Plasma

SED Disadvantages

Cost

Availability

Extra

http://www.youtube.com/watch?v=hxv7mmKHRhs

Sources http://electronics.howstuffworks.com/lcd.htm http://electronics.howstuffworks.com/oled1.htm http://electronics.howstuffworks.com/plasma-display.htm http://entertainment.howstuffworks.com/sed-tv.htm http://www.howstuffworks.com/tv.htm http://www.howstuffworks.com/tv3.htm http://electronics.howstuffworks.com/dlp.htm http://reviews.cnet.com/8301-12760_7-9673322-5.html?tag=txt http://reviews.cnet.com/8301-12760_7-9674057-5.html?tag=txt