What is meaning of LCD projector

'LCD' is the short form for 'Liquid Crystal Display' and is the same technology that you find inside an LED/LCD TV. The LCD panel is made up of millions of tiny Liquid Crystals, one each for every pixel in a Digital picture: that means for the High Definition HD format there will be 1920x1080 which equals to just over 2 million Liquid crystals in each tiny LCD Chip which goes into a projector.

Each Liquid crystal can independently turn 'on' or 'off' with an electric voltage applied to it. When in the Opaque state it blocks the passage of light through it and when in the transparent state, will allow light to pass through.

Thus the LCD chip acts like the film rolls used in projectors of the old Cinema houses. Those film rolls had translucent coloured images imprinted on the film and a bright light beam passed through the film to project the colored film picture on to the cinema screen. In a digital picture the color picture signals are in RGB: Red, Green and Blue color information. In 3LCD projector, 3 separate RGB: Red, Green and Blue light beam is passed through 3 separate LCD chips and then the outgoing beams of RGB light are combined by prisms back into a multicolored beam and projected on to the screen.

LCD projectors are mostly 3 chip projectors and mostly based on the '3LCD' brand configuration as shown in the image above. 3LCD is a technology was pioneered in the 1980s by the Japanese Company 'Seiko Epson', famous for their Watches and also the makers of Epson Projectors and Printers. The 3LCD technology is now marketed by an Epson affiliated Company known by the same name: '3LCD'. Epson has licensed the 3LCD technology out to many other projector manufacturers.

How the EPSON 3 LCD projector works is explained in the picture above. A bright white light source is split into individual beams of RGB light, using 3 Dichroic mirrors. Dichroic mirrors are mirrors which reflects certain wave length light and let others pass through. In the case of the 3LCD projector, the first Dichroic mirror reflects Red light but allows Green and Blue light to pass through. The second Dichroic mirror reflects Green but lets Blue light through and the final mirror reflects the remaining Blue light.