what's the difference between LCD and plasma TV?

Answer 1

A plasma display panel (PDP) is an emissive flat panel display where light is created by phosphors excited by a plasma discharge between two flat panels of glass. The gas discharge contains no mercury (contrary to the backlights of an AMLCD). An inert mixture of noble gases (neon and xenon) is used instead.


A liquid crystal display (LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is prized by engineers because it uses very small amounts of electric power, and is therefore suitable for use in battery-powered electronic devices.

Each pixel consists of a column of liquid crystal molecules suspended between two transparent electrodes, and two polarizing filters, the axes of polarity of which are perpendicular to each other. Without the liquid crystals between them, light passing through one would be blocked by the other. The liquid crystal twists the polarization of light entering one filter to allow it to pass through the other.

The molecules of the liquid crystal have electric charges on them. By applying small electrical charges to transparent electrodes over each pixel or subpixel, the molecules are twisted by electrostatic forces. This changes the twist of the light passing through the molecules, and allows varying degrees of light to pass (or not to pass) through the polarizing filters.

Before applying an electrical charge, the liquid crystal molecules are in a relaxed state. Charges on the molecules cause these molecules to align themselves in a helical structure, or twist (the "crystal"). In some LCDs, the electrode may have a chemical surface that seeds the crystal, so it crystallizes at the needed angle. Light passing through one filter is rotated as it passes through the liquid crystal, allowing it to pass through the second polarized filter. A small amount of light is absorbed by the polarizing filters, but otherwise the entire assembly is transparent.

When an electrical charge is applied to the electrodes, the molecules of the liquid crystal align themselves parallel to the electric field, thus limiting the rotation of entering light. If the liquid crystals are completely untwisted, light passing through them will be polarized perpendicular to the second filter, and thus be completely blocked. The pixel will appear unlit. By controlling the twist of the liquid crystals in each pixel, light can be allowed to pass though in varying amounts, correspondingly illuminating the pixel.

Many LCDs are driven to darkness by an alternating current, which disrupts the twisting effect, and become faint or transparent when no current is applied.

To save cost in the electronics, LCDs are often multiplexed. In a multiplexed display, electrodes on one side of the display are grouped and wired together, and each group gets its own voltage source. On the other side, the electrodes are also grouped, with each group getting a voltage sink. The groups are designed so each pixel has a unique, unshared combination of source and sink. The electronics, or the software driving the electronics then turns on sinks in sequence, and drives sources for the pixels of each sink.

Important factors to consider when evaluating an LCD monitor include resolution, viewable size, response time (sync rate), matrix type (passive or active), viewing angle, color support, brightness and contrast ratio, aspect ratio, and input ports (e.g. DVI or VGA).

Answer 2

Did you mean what's the difference in technology? If so, that has been answered. If you are asking about performance differences, then here is a summary of key points:

Picture quality of plasma is brighter, better color, better blacks than LCD. (There is something about looking directly at glowing phosphors!)

Sharpness is the same for equivalent pixel counts. Some newer LCDs have 1080 x 1920 resolution, most plasmas still in the 720 x 1250 range.

Plasma is heavier and uses more power.

There are reports that plasmas are not as reliable, but that may not be true with the latest models.

Plasmas are subject to burn-in. A stationary image left on the screen for a long time could produce a permanent ghost image. The most risk is when viewing a lot of 4:3 ratio pictures (non-HD), which are displayed with vertical dark areas on the left and right to fill in the wide screen. There are ways to minimize this, however. many sets have a "stretch" mode which widens the picture to fill the whole screen.

Plasmas come in largers sizes, although large LCDs are coming out, but they are expensive.

LCD contrast and brightness can be reduced when viewing from off-center.

Answer 3

LCD uses a lamp to shine thru the individual LCD panels (R, G, B) which are controlled to be either tranparent or opaque or anywhere inbetween.
Plasma uses electricity to illuminate gas. Gas is sandwiched between 2 glass plates with transparent electrodes. Then voltage is applied to one of the electrodes, a surface electrical discharge produces ultra violet rays that excite the colored phosphors painted inside the opposite plate of glass, emitting light through the glass plate to create an image. Because the phosphors are painted in red, green and blue, the image produced is in color.

Answer 4

grumpy mac is grumpy... but he does raise a fair point. thousands of resources on this questions and its not a short answer plasma for sports and fast action and realistic colors LED if you have a lot of windows and light coming into the room.. and most of all, personal preference.. go to a best buy magnolia or some place that has a darkened room to test out the differences

Answer 5

lcd u can watch straight and plasma u can watch frm any angle u will se th picture