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UE7465

PLASMA DISPLAY PANEL

What is plasma panel display ?

PDP is a type of flat panel display

Many tiny cells between two panels of glass hold a mixture of noble gases.

The gas in the cells is electrically turned intoa plasma which then excitesphosphors to emit light.

Need For The PDP

Former CRT TV’S were very bulky.

To increase the screen width in a CRT set, you also have to increase the length of the tube . So overall size increases a lot.

Power consumption was high in CRT TVs.

To improve the picture quality .

What Is Plasma ?

Plasma is a partially ionized gas, in which a certain proportion of electrons are free rather than being bound to an atom or molecule.

Generated by passing low frequency RF (<100 kHz) electric field to the gap between two metal electrodes.

Basic Construction Of Plasma Display

Consists two plates of glass containing gases helium , xenon, neon.

These gases are in form of tiny cellsElectrodes are there in front and back of

these cellsAddress electrode is along the rear of glass

plateDisplay electrode which is transparent is in

front of glass plateVoltage across electrodes creates ionization

of gases to form plasma.

Figure showing different layers

Colour Controlling

The back of each cell is coated with a phosphor of different colours which are Red ,Blue and Green.

These three cells make one pixel.

By varying the pulses of current flowing through the different cells thousands of times per second, the control system can vary the intensity of each subpixel colour to create billions of different combinations of red, green and blue.

Figure showing pixels along with the different layers of PDP

Contrast Ratio

Contrast ratio is the difference between the brightest and darkest parts of an image.

Contrast ratios for plasma displays can be as high as 1,000,000:1.

Each cell on a plasma display has to be precharged which doesn’t allow plasma to achieve a true black.

Screen Burn-in

The phosphor compounds which emit the light lose their luminosity with use.

Certain areas of the display which are used more frequently looses its luminosity and the result is called burn-in.

Most plasma display producers state a 100,000 hours time before brightness halves, giving it over 10 years of life.

Response time

A screen’s response time is a measure of how fast its pixels can complete one full picture ‘cycle’, so that they’re ready to play a part in the next frame of the picture.

Screens with long response times can have moving objects looking blurred and smeared.

Plasmas uses just a pulse to produce a picture so response time is instantaneous.

Viewing angle

Viewing angle is the maximum angle at which a display can be viewed with acceptable visual performance .

Due to the fact that Plasma display emit light directly from each of their screen cells or pixels. Plasma TVs can actually be watched from very wide viewing angles without any significant loss in colour or contrast.

Energy consumption

Plasma TVs require just a single ignition of a plasma cell to cause a pixel to illuminate. Since darkness is achieved in plasma pixels by stopping electrical current getting into them, it follows that plasma TVs need relatively little power to reproduce dark scenes.

So overall energy consumption is less than CRT’s but more than LCD’s

Advantages of plasma display

Slim profileCan be wall mountedLighter and less bulky than rear-projection televisionsAchieves better and more accurate colour reproduction

than LCDs (68 billion (236) versus 16.7 million (224)) Produces deep, true blacks allowing for superior

contrast ratios (up to 1,000,000:1) Far wider viewing angles than those of LCD (up to 178°)Virtually nonexistent motion blur, contributes to the

superior performance of when displaying rapid motion

Disadvantages of Plasma Display

Cost is much high for sizes smaller than 32 inches.

Lower brightness which makes it susceptible to reflection glare in bright rooms.

Heavier than LCD due to the requirement of a glass screen to hold the gases.

Uses more electricity, on average, than a LCD TV.

Less resolution than LCD’s

Current Market Status

Plasma display is facing a tough competition from LCD technology.

According to industry estimates, for every one plasma TVs sold there are at least eight LCD TVs .

The sale in Plasma TVs this year is nearly constant whereas for LCD TVs rise in sale is 141 %

Reasons For Down Market

Plasmas are available in size more than 32 inches whereas demand is more for small size screens .

Plasmas cant be used with computers whereas LCD can be interfaced .

Due to improvements in technology LCD has become more slim and lighter than plasmas .

Plasmas Doesn’t offer high resolution such as 1920 X 1080 (1080P) which is easily available in LCDs

Thank You