LCOS (Light Crystal Over Silicon) is a technology used in display systems.
LCOS combines with two ideas: -
LCD (Liquid Crystal Display) and DLP (Digital Light Processing) displays.
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.
DLP uses tiny mirrors, one for each pixel, to reflect light. DLP modulates the image by tilting the mirrors either into or away from the lens path. It is therefore a "reflective" technology. So, these two technology makes the LCOS much more better for our display technologies.
Lets, talk about how LCOS works: -
The process begins with an intense light beam that is passed through a condenser lens. This lens has employed for focusing and directing the beam. It has a filter which allows to pass only visible light. The white light is separated into separate colored components by polarizing it with the use of a light beam splitter. This device passes the beam through separate filters. After this particular stage, the single light beam is separated into three and each has a different color which are RED, GREEN and BLUE.
Alternatively, to separate the different colored light beams we use Dichroic mirrors. This Dichroic mirrors reflect or block some wavelengths of light while it allows to pass the rest through. One mirror can block blue light and allow to pass the red and green then, second mirror blocks the red light which means only the green light passes through. Each of the individual beams then hits a designated LCOS micro-device. Each Micro Device has a liquid crystal layer which is sandwiched between a clear TFT and a silicon semiconductor. The colored beam passes through polarizing filters to strike the Micro Device. The liquid crystals act as a control device that manages the amount of light which hits the pixilated, reflective surface of the silicon semiconductor.
The light reflected from these micro-devices is passed through a prism which combines the light and creates a full-color image. This is directed through a projection lens that renders the image on the screen.
Advantages and Disadvantages of the LCOS: -
LCOS systems produce better and more natural looking image displays than their LCD or PLP counterparts. LCOS produces smoother and seemingly more refined images. But, to produce these qualities we have to involved in a convoluted process which is the primary drawback of the displaying images. LCOS system has higher cost as compare to LCD and DLP.
