The Plasma TV Blog

The major difference between LCD and DLP TV is the manner in which the image is transferred from the electronic video signal to the screen. The CRT (cathode ray television) was the first method, and had served well providing a very high picture quality and contrast, but it had the disadvantage of size. As the demand increased for larger viewing areas, the CRT became a less attractive option as the larger the screen size, the more depth that was needed in the cathode ray tube. LCD and DLP were two of the new technologies that were developed to address this problem.

The LCD uses two polarized flat panels made up of small liquid crystal cells. They are placed in such a manner that light is blocked from passing from one cell to another unless an electrical charge is applied to the crystal which in effect, twists the light to pass through to the next panel, and light the pixel on the screen. Color is provided by what is basically a matter of subtraction. Various color wave lengths are blocked from pure white light, which contains all colors, until the right color is all that is left. This method provides a great variety of color possibilities.

The DLP is a rear projection type of television that uses a large number of micro mirrors to reflect light toward the pixels. The tilt of the mirrors is controlled by the incoming video signal. The color is provided by passing the light through a rapidly spinning color wheel.
The major advantage of the LCD is the reduction in size. LCD TV loses a bit when the screen size is enlarged to the popular Home Theatre sizes, but at smaller sizes it is comparable with the CRT, although the monitor can be almost flat. The major advantage of the DLP is that it is capable of being utilized in large screen applications with a considerable decrease in depth, and very little loss of picture quality.