In Liquid Crystal Display projectors, a light source typically shines through a layer of liquid crystal material. Because the light is transmitted through the layer, this form of projection technology is commonly labeled transmissive.

LCD projectors range from mid-sized to very small, medium weight (20 kilos or so) to very light (under 3 kilos), and have become increasingly standardized (and hence easy to set up and use), making them the most popular choice for a wide variety of presentation applications.

In LCD projectors, a light source typically shines through a layer of liquid crystal material. Because the light is transmitted through the layer, this form of projection technology is commonly labeled transmissive. An electrical charge is applied to the crystals in the layer, causing them to rotate the plane of polarized light - in effect, turning different colors on or off. Each pixel (colour dot) projected to a screen is generated by three separate crystal cells, one each to produce red, green and blue color signals. The polarized light coming out of the layers passes through a prism to create the unified projected image your audience sees.

The performance of the projector is determined by a variety of components, most significantly the quality of the transistor layer that controls the liquid crystals. Newer projectors use polysilicon transistors - which are smaller, absorb less light (making the projected image brighter) and switch faster than earlier generations - and have three separate layers to produce the colour signals going into the projection prism.

In the context of alternative technologies of the same basic size and weight, LCD projectors have the advantage of being the more-established technology, which means the installed base is larger, and hence more people are experienced in setting up and using this form of presentation support.

LCoS Technology:

Liquid Crystal on Silicon - a hybrid technology in which the light is reflected off modified LCD panels to offer some of the benefits of DLP particularly at higher contrast levels and a higher "perceived" resolution because of the smoothness of the image. LCoS has yet to gain the market acceptance of DLP or LCD, but it is very well suited to presentation applications that show fine detail or graphics and require higher projected resolutions.

next to DLP® technology