Comparison of LCD & Plasma HDTVs

Both LCD and plasma HDTVs have excellent picture quality.

LCD (liquid crystal display) and plasma are two popular technologies for flat-screen, high-definition television (HDTV). Each technology may have some advantages and benefits over the other, in terms of one or more aspect of performance, but no one technology is universally better than the other. In a plasma HDTV, millions of small glass cells emit ultraviolet (UV) light to display an image, while an LCD HDTV uses crystals that reposition themselves in liquid panels, blocking light in some areas and allowing it to pass through in others, forming the images on screen.

Contrast Ratio

The contrast ratio for a TV is a measure of how clearly it can produce and discern between extreme colors. The contrast ratio is expressed as a ratio of "brightest white light against darkest black," with higher values producing clearer pictures. Plasma HDTVs are better capable of discerning between extreme colors, compared to LCD HDTVs. For example, subtle differences in a portion of the screen displaying a dark image will be better generated and displayed in a plasma HDTV, whereas in an LCD HDTV, the various degrees of black may dissolve into each other. Contrast ratios for plasma TVs are typically in the 200:1 range, and for an LCD TV, the average ratio is 400:1.

Saturation

In HDTV technology, color saturation is a measure of the amount of gray there is in a color, where more presence of gray corresponds to lower saturation values. A plasma HDTV screen, owing to its operational technology, is able to switch off pixels. When a pixel is turned off, there is no interference with adjacent pixels (that may be active), and as a result, there is little or no saturation due to stray light. An LCD HDTV screen, unable to turn pixels on and off like a plasma screen, produces some color saturation when bright on-screen images have some stray light.

Brightness

For most consumers, screen brightness is an important measure of HDTV performance. Technically, brightness is measured in cd/m2 (candelas per squared meter) for LCD and plasma screens. Plasma TVs usually have a measurement of 100 cd/m2, while for an LCD TV, it may be as high as 450 cd/m2. The higher cd/m2 value for an LCD HDTV means that its screen can display brighter images than a plasma screen. If the two screens are playing the same video, and if video settings for both the LCD and plasma screens are set at default, the LCD screen will be brighter.

Applications & Ideal Setting

Some attributes of LCD HDTVs make it more suitable for use as a gaming display screen or computer monitor. Burn-in refers to the tendency of some screen to hold a color for longer than intended. Burn-in occurs when a very bright image is displayed on the same region of the screen for a long time. Plasma HDTVs may occasionally suffer from some burn-in, but LCD HDTVs never experience the phenomenon. LCD HDTVs are also less reflective than plasma HDTVs, and may look better in a brightly-lit environment.

Angular Viewing

A plasma HDTV has a very wide viewing angle, and viewers from the side can see more or less the same image as viewers from the center, with no loss in quality. In an LCD HDTV, some degradation occurs when viewing the screen from an angle.

References

• Ecoustics: LCD vs. Plasma TVs
• Consumer Reports: LCD vs Plasma