LCD uses liquid crystals one for every pixel. The light goes through them on its way to the lenses and it in modulated by the liquid crystals that it is traversing. It is a transitive technology. The DLP uses microscopic mirrors, one for every pixel reflecting the light. This is a modulating technology and it is reflexive.

LCOS is a combination from these two technologies. Mainly it is a reflexive technology using liquid crystals instead of individual mirrors. At LCOS, the liquid crystals are applied on a reflexive, mirror like, type layer. As the crystals open and close the light is reflected but not towards the mirror they are applied on. This is how the image is created. The LCOS projectors are using mainly 3 chips one for the modulation of the light on the channels red, green and blue. Similar to LCD, LCOS projects the red, green and blue components simultaneously. The rotating disc from DLP technology is absent.

The LCOS technology has a very high resolution and naturally is more expensive than the majority of LCD or DLP products. There are no SVGA resolutions at LCOS projectors and seldom XGA equipments. Generally the LCOS projectors come with SXGA (1365x 1024) technologies or higher and that is why, by definition, they are not cheap.

So, due to the high resolution and the large dimension, the LCOS technology was not adapted for the slender, portable video projectors. The LCD and DLP projectors are presently selling in large quantities and are the best sold options for mobile, educational and Home Theater usage; this is the reason for which they are enjoying a higher attention. Because LCOS is not sold in similar quantities many people believe it is not that good. This is not correct at all. Many well informed video-fans looking for elegant solutions in home theaters are choosing the LCOS technology due to those characteristics that neither LCS nor DLP can use.

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