3LCD

3LCD is the name of one of the main technologies used in modern digital projectors. 3LCD technology was pioneered by Epson in the 1980s and was first used in a projector that was launched in 1989. 3LCD is today marketed by an independent organization called the [3LCD Group] that has licensed the technology to about 40 different projector manufacturers worldwide. Citing findings by research company Pacific Media Associates in 2009, the 3LCD Group claims that projectors using 3LCD technology comprised about 51% of the world's digital projector market in 2008.

The technology gets its name from the three LCD panel chips used in its image generation engine.

Creating Colours from White Light: A projector using 3LCD technology works by first splitting the white light from the lamp into its three primary colours of red, green and blue by using special dichroic filter / mirror assemblies called “dichroic mirrors.” Each dichroic mirror only allows specific coloured wavelengths of light to pass through while reflecting the rest away. In this way, the white light is split into its three primary colour beams and each is directed toward its own LCD panel

Image Generation at the LCDs: The three LCD panels of the projector are the elements that receive the electronic signals to create the image which is to be projected. Each pixel on an LCD is covered by liquid crystals. By changing the electrical charge given to the liquid crystals, pixels on an LCD can be darkened until they are totally opaque (for full black), lightened until they are totally transparent (allowing all the lamp light to pass through for full white), or shaded in varying degrees of translucence (for different shades of gray).

This is similar to how a digital watch’s characters appear bold and black on its LCD when its battery is new, but start to fade gradually as its battery weakens. In this way, the brightness level for every pixel can be very precisely controlled.

Colour Image Recombination and Projection: After each coloured light is filtered through its individual LCD panel, the beams are recombined in a dichroic prism that forms the final image which is then reflected out toward the lens. This results in images with rich and full colour, since all three basic colours are included in each pixel of the projected image at all times.

The main competitors to Epson's 3LCD technology are Texas_Instruments's 1-Chip DLP and LCOS projection technologies.

^[1]

• 3LCD Group web site