LCD vs Plasma

At present consumers who have decided that a flat panel display best suits their needs have a choice between plasma or LCD (Liquid Crystal Display) technologies. Both have strengths and weakness and selection is dependent upon the individual consumer’s needs and preferences. Presently, LCD HDTV have a significant number of sales lead over plasma HDTV. A look at the Bestselling flat panel list at Amazon will give an idea of the relative popularity of each display type.

Plasma Display Technology in Brief

Plasma technology is based on pixels containing three sub-pixels of microscopic fluorescent lamps in the primary colors red, green and blue. Variation of the intensity of these sub-pixels produces a wide palette of colors combined by the human eye. The lamps don’t actually produce a visible light requiring a scintillator (phosphor) coating which converts the invisible radiation into visible light. As there are millions of sub-pixels in high definition display, multiplexing is used rather than individual sub-pixel control wires. Each sub-pixel is on a unique combination of horizontal and vertical control lines and is addressed by the display electronics when required to turn on. Alternative Coplanar Current (ACC) is another wide-spread plasma panel type. ACC panel control is more complex with each sub-pixel having three electrodes.

Plasma Display Strengths

wider, more vibrant color range equating to more realistic pictures. Plasma displays do not create the RGB (red, green, blue) sub-pixels by filtering as with an LCD and have a wider range of color reproduction from the scintillator materials available.
widest viewing angles (compared to plasma) providing flexibility to place seating further out from the centreline of the display without compromising image quality
deeper blacks with more detail in darker scenes (off plasma pixel emits no light whereas LCD have a backlight)
superb contrast for better rendering of subtle color details and improved viewing in higher ambient light settings
excellent motion handling (eg. sports broadcasts without blur of fast moving objects)
long display life commonly ranging from 60,000 to 100,000 hours

Plasma Display Weaknesses

some burn-in susceptibility (permanent shadow on screen) from overexposure of parts of a screen to the same image however, manufacturer’s are steadily reducing the risk through technologies like pixel shifting
size restriction due to plasma pixel size limitations mean that the smallest size is about 42 inches (diagonal)
higher cost for display size than LCD due to difficulty of manufacture and component costs.
sitting too close to a plasma screen may cause eye discomfort - due to flickering from Pulse Code Modulation (PCM) brightness control. Plasma pixels have two states, on (lit) or off (dark), requiring manufacturers to use PCM to vary brightness by varying frequency with which pixels are lit.

LCD Technology in Brief

LCD pixels don’t emit any light. All the qualities but, also all the faults of the technology stem from that key characteristic. As with plasma displays, an LCD pixel is made up of three primary color sub-pixels. Backlighting is required as the LCD doesn’t emit any light working more like a light valve. Color is added filters with the amount of light allowed to pass through each LCD sub-pixel (valve) providing intensity control. This is a very simplified explanation with the actual physics involved depending upon polarization of light. Importantly though, LCD pixels can be modulated to provide intermediate states between on and off as opposed to plasma pixels.

LCD Display Strengths

small pixel sizes possible make an LCD display the option for screen sizes below 40 inches (101 cm) LCD have higher resolution for the same screen size
price for display size advantage due to lower manufacturing costs associated with use of lithographic production techniques pioneered by the computer chip industry
significantly lower power consumption than plasma displays of the order of 30%
no flicker making them easier on the eye from closer distances.
generally lighter and slimmer than plasma displays
long display panel life commonly 60,000 hours

LCD Display Weaknesses

slightly narrower viewing angle range there is dimming and color shift at shallower angles than plasmas
more prone to motion blur but, performance gap is closing with faster refresh rates (down to 4 msec) and higher frame rates