Everything You Need to Know About TV Technologies

Plasma

It’s time to enter the realm of futuristic flat-panel TV, the kind of display that existed in science fiction for decades before becoming real with the advent of plasma and LCD televisions. Let’s talk about plasma first: the display is composed of two panels of glass holding tiny cells full of a mixture of noble gases (xeon and neon). An electrical charge turns the gas into plasma. The ultraviolet photons emitted by the plasma excite the phosphor coating in the back of each cell to give off colored light. They become like fluorescent lamps and can be ionized 85 times per second. The latest generation of plasma displays has a lifetime of 60,000 hours, or 27 years at 6 hours per day. After that, the brightness level goes down by 50%. Bear in mind that a traditional CRT television loses about 30% of its brightness after 20,000 hours of use.

The main problem concerning first generation plasma displays was screen burn-in. Static images like TV channel logos and other graphical elements could over time burn them unto the screen. The phosphor was to blame since it got tired of the pixels being lit and unlit over and over following the same pattern to form a particular image. Nowadays the plasma manufacturers have devised several countermeasures to screen burn-in, like improving the quality of the phosphor coating and washing routines to shake up the static graphical elements so they cannot be imprinted upon the screen. Plasma displays can reach resolution of Full HD and be as big as 150 inches (like a recent model unveiled by Panasonic). The technology, however, is loosing ground to LCD displays. A study that included consumer surveys spanning six countries in three regions – North America (United States and Canada), Asia Pacific and Europe (United Kingdom, France and Germany) – said that plasma TV will have less than 15% of the flat-screen displays market share by 2011.

Model example: LG 50PG20 (50” 720p HDTV)

Strong points

• Can be as big as 150 inches.
• Excellent black level and better colors than LCD.
• Big viewing angle.

Weak points

• Risk of burn-in still exists.
• High power consumption.
• Gets hot.
• Models are 20% heavier than same screen size LCD counterparts.
• High resolution models are more expensive than LCD with the same screen resolution.