The LCOS technology is a hybrid of LCD (Liquid Crystal Display) and DLP (Digital Light Processing) technology. LCD uses liquid crystals, one for each pixel, on glass panels. Light passes through these LCD panels on the way to the lens and is modulated by the liquid crystals as it passes. Thus it is a "Transmissive" technology.

This is a reflective technology that uses liquid crystals rather than individual mirrors. In LCOS, liquid crystals are applied to a reflective mirror substrate. As the liquid crystals open and close, light is either reflected from the mirror below, or blocked. This modulates the light and creates the image.

LCOS-based projectors typically use three LCOS chips to modulate light in the red, green and blue channels.

The Advantages of LCOS

The LCOS technology have several key advantages over other more established technologies like the LCD and DLP. First, due to inherent high resolution and high fill factors (minimal space between pixels) on the chips, visible pixelation on an LCOS machine is almost nonexistent. Even close up the pixel structure from the LCOS is less visible than what you get with the high resolution 1280x720 DLP chip. Hence, the resulting video image is smoother.

Next, with LCOS the pixel edges tend to be smoother compared to the DLP. This gives them an analog-like response, whereas micro-mirrors add high frequencies that accentuate their digital nature. In practical terms, this gives the LCOS image a smoother, more natural look and feel, while DLP tends to impart a synthetic sharpness to the image that some photographers would describe as harsh.

Third, LCOS and LCD projectors deliver continuous red, green and blue simultaneously onto the screen. Single-chip DLPs deliver color sequentially, alternating between red, green and blue one color at a time. Though DLP projectors are capable of delivering rich, well saturated colors, thus LCOS products tend to be more superior in this regard.