About LCoS Projection TV Technology

Liquid crystal on silicon (LCoS) is a "micro-projection" or "micro-display" technology most used in projection televisions. It is a reflective technology similar to DLP projectors, but uses liquid crystals instead of individual mirrors. In an LCoS Projection TV, liquid crystals are applied directly to the surface of a silicon chip coated with an aluminized layer, with some type of passivation layer, which is highly reflective. LCoS technology can produce much higher resolution images than liquid crystal display (LCD) and plasma display technologies, which makes it less expensive to implement in televisions and similar devices.

LCoS Projection TV technology has the potential to enable the manufacture of big screen high-definition televisions (HDTV) with very high picture quality at relatively low cost. LCoS can, however, be a difficult technology to master. A number of companies have dropped out of the LCoS Projection TV business in recent years. At the 2004 CES, Intel announced plans for mass production of inexpensive LCoS chips for use in flat panel displays. These plans were cancelled in October 2004.

Nonetheless, as of June 2006, proprietary methods for mass production LCoS Projection TV have been developed, and at least four manufacturers now produce LCoS rear-projection televisions for the mass market. Sony has made it to market with the Sony-VPL-VW100 or "Ruby" projector, using SXRD, 3 LCoS chips each with a native resolution of 1080p (1920 × 1080), and a stated contrast ratio of 15,000:1 using a dynamic iris.

Commercial implementations of LCoS technology include Sony's SXRD (Silicon X-tal Reflective Display) and JVC's D-ILA (Digital Direct Drive Image Light) Amplifier. Most companies which produce and market a LCoS Projection TV uses three panel LCoS technology. Sony and JVC also produce and market front projection displays that use three LCoS panels.

In a three panel LCoS device the light is separated into three components and then combined back. Two beam splitters are needed. In LCoS Projection TV the light is additionally polarized and then analyzed; four beam splitters are needed. In most LCoS Projection TV set a color wheel separates colors from a lamp, using one chip for all three colors. SXRD sets use three separate chips, one for each color (red, green, and blue respectively).

Direct-view LCoS Projection TV devices such as the single panel, LED illuminated devices made by Displaytech and Forth Dimension Displays are also used as electronic viewfinders for digital cameras and within Near to Eye (NTE) applications such as Head Mounted Displays (HMDs). These devices are made using ferroelectric liquid crystals, which are naturally faster than other types of liquid crystals.