MODERN DISPLAYS

Submitted By :-

Anuj Rakheja

Evolution Of Displays:-

Display is the most interesting topics now days, as the technology is increasing day by day, similarly our need are also increasing.

Today we will discuss about the displays and their evolution with time.

First of all we will start with:

Types Of Displays:-

CRT (Cathode Ray Tube) TFT (Thin Film Transistor) LCD (Liquid Crystal Display) LED (Light Emitting Diodes) OLED (Organic Light Emitting Diodes) OFET (Organic Field-Effect Transistor)

Cathode Ray Tube Display:-

We all are familiar with display We are currently using it in our Labs.

Its Advantage:-

Cheaper, Easily applicable, Easily available,

Disadvantages:-

Uses much electricity, No higher resolution supported, Difficult to create display practically above

30”, Bigger size, Heavyweight, Heats Up.

About:-

In a CRT the electron beam is produced by heating a metal filament, which "boils" electrons off its surface.

The electrons are then accelerated and focused in an electron gun, and aimed at the proper location on the screen using electromagnets.

The majority of the power budget of a CRT goes into heating the filament, which is why the back of a CRT-based television is hot.

The atmospheric force on the front face of the tube grows with the area, which requires ever-thicker glass.

This limits practical CRTs to sizes around 30 inches; displays up to 40 inches were produced but weighed several hundred pounds, and televisions larger than this had to turn to other technologies like TFT:-

THIN FILM TRANSISTER:-

A TFT monitor uses thin-film transistor technology for the ultimate LCD display. LCD monitors, also called flat panel displays, are replacing the old style cathode ray tubes (CRTs) as the displays of choice. Nearly all LCD monitors today use TFT technology.

PHYSICAL STRUCTURE:-

Inner Structure:-

1 - Glass plates 2/3 - Horizontal and vertical polarisers 4 - RGB color mask 5/6 - Horizontal and vertical command lines 7 - Rugged polymer layer 8 - Spacers 9 - Thin film transistors 10 - Front electrode 11 - Rear electrodes

BENEFIT:-

The benefit of a TFT monitor is a separate, tiny transistor for each pixel on the display. Because each transistor is so small, the amount of charge needed to control it is also small. This allows for very fast re-drawing of the display, as the image is re-painted or refreshed several times per second.

DISADVANTGE:-

A typical 17-inch TFT monitor has about 1.3 million pixels and 1.3 million transistors. Upon delivery, a TFT monitor can have "dead pixels" for this reason.

A dead pixel is a pixel whose transistor has failed, thereby creating no display image. On a solid black background, dead pixels will stand out as tiny dots of red, white or blue. Most manufacturers will not replace a TFT monitor that has less than 11 dead pixels. This was a good technology but due to some disadvantage we moved on to LCD in association with TFT technology.

Liquid Crystal Display:-

A liquid crystal display (LCD) is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals. Liquid crystals do not

emit light directly.

Applications:-

LCDs are used in a wide range of applications including computer monitors, televisions, instrument panels, aircraft cockpit displays, and signage.

They are common in consumer devices such as video players, gaming devices, clocks, watches, calculators, and telephones, and have replaced cathode ray tube (CRT) displays in most applications.

They are available in a wider range of screen sizes than CRT.

LCD TAKEN OF MARKET WIDELY:-

In 2008, LCD TV shipments were up 33 percent year-on-year compared to 2007 to 105 million units. In 2009, LCD TV shipments raised to 146 million units (69% from the total of 211 million TV shipments) .In 2010, LCD TV shipments reached 187.9 million units (from an estimated total of 247 million TV shipments).

Current major manufacturers such as Sony, Sharp Corporation, LG Display, Panasonic and Samsung have announced larger sized models:

In October 2004, Sharp announced the successful manufacture of a 65" panel.

In March 2005, Samsung announced an 82" LCD panel. In August 2006, LG Display Consumer Electronics

announced a 100" LCD television In January 2007, Sharp displayed a 108" LCD panel

under the AQUOS brand name at CES in Las Vegas.

But The Main Disadvantage:-

LCD don't emits light directly, it produce the image on the last layer, so because of this view angle is limited.

An LCD have a Maximum angle of 160-170 degrees.

Also

Although current LCD panels are able to deliver all sRGB colors using an appropriate combination of backlight's spectrum and optical filters, manufacturers want to display even more colors.

One of the approaches is to use a fourth, or even fifth and sixth color in the optical color filter array. Another approach is to use two sets of suitably narrowband backlights so here comes LEDs:

Light Emitting Diodes:-

LED TV is just an LCD TV that's backlit with light-emitting diodes (LED’s) instead of standard cold-cathode fluorescent lights (or CCFL’s)

Instead of led TV they should be called as LCD/LED TV.

Technology:

There is a new backlight technology that is becoming available that uses Light Emitting Diodes (LEDs) for the backlighting requirements. There are numerous advantages to this technology over CCFLs, so device is likely to be significantly thinner than its CCLF powered counterparts. So do not need bulky fluorescent tubes.

LEDs are also powered by standard low voltage electronics and are much more efficient at producing light than CCFLs are.

This leads to a brighter image and better power efficiency.

LED TV By Sony:-

Some General Form Of LED:-

The future of LED Technology - OLED

Here OLED is ORGANIC LED, This new technology replaces the need for a

backlight all-together as each pixel produces its own light:

This is a diagram

showing pixels in an led>>

This Show The Diff. in LCD and OLED:

AMOLED:

A type of OLED : AMOLED (active-matrix organic light-emitting diode) is a display technology for use in mobile devices and televisions.

As of 2012, AMOLED technology is used in mobile phones, media players and digital cameras, and continues to make progress toward low-power, low-cost and large-size (for example, 40-inch) applications.

Till now samsung has offered Super AMOLED display for some limited products.

SUPER AMOLED:

Samsung's Super-AMOLED displays are AMOLED displays with an integrated touch function.

Samsung has placed a touch-sensor (on-cell) over the display and made it evaporate. The thickness of the touch sensor is just 0.001mm (!) this allows the screen to provide better images and to have great visibility even in direct sunlight (Samsung says that they perform 20% better than regular touch AMOLED outdoors).

Super-AMOLEDs also have better lifetime than regular AMOLED and are very responsive to touch - even better than the iPhone's display.

Super-AMOLED have been announced in January 2010

Super AMOLED Plus

In January 2011 Samsung announced their next-gen AMOLED displays called Super AMOLED Plus.

The major advance is that the new displays use regular sub-pixel design which means 50% more sub-pixels and a clearer display.

Super AMOLED Plus displays are also thinner, brighter and use 18% less energy.

OFET (Organic Field-Effect Transistor):

It is a field effect transistor using an organic semiconductor in its channel,

By this we can create flexible display:-

OFETs can be prepared either by vacuum evaporation of small molecules,

by solution-casting of polymers or small molecules, or by mechanical transfer of a peeled single-crystalline organic

layer onto a substrate. These devices have been developed to realize low-cost, large-

area electronic products and biodegradable electronics.

This Was All About Modern Displays.

Thank You.