Liquid crystal on silicon 471167 216244075 2008-05-31T19:44:52Z Gjon1024 7220503 '''Liquid crystal on silicon''' ('''LCOS''' or '''LCoS''') is a "micro-projection" or "micro-display" [[technology]] typically applied in projection [[television]]s. It is a reflective technology similar to [[DLP]] projectors; however, it uses liquid crystals instead of individual mirrors. By way of comparison, [[LCD projector]]s use transmissive [[LCD]] chips, allowing light to pass through the liquid crystal. In LCoS, 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]] and [[plasma display]] technologies, which makes it less [[Cost|expensive]] to [[Implementation|implement]] in such [[Display device|device]]s as televisions. At the 2004 [[Consumer Electronics Show|CES]], [[Intel]] announced plans for the large scale production of inexpensive LCoS chips for use in flat panel displays. These plans were cancelled in October 2004. [[Sony]] has made it to market (December 2005) with the Sony-VPL-VW100 or "Ruby" projector, using SXRD, 3 LCoS chips each with a [[native resolution]] of [[1080p]] (1920 × 1080), with a stated [[contrast ratio]] of 15,000:1 using a dynamic iris. == History and implementations == LCoS technology has the potential to enable the manufacture of big-screen high-definition televisions with very high picture quality at relatively low cost. LCoS, while conceptually straightforward, can be a difficult technology to master; a number of companies have dropped out of the LCoS business in recent years. Nonetheless, as of June [[2006]], proprietary methods for mass-producing LCoS developed, and at least four manufacturers now produce LCoS-based rear-projection televisions for the consumer market. 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. Every company which produces and markets LCoS rear-projection televisions uses three-panel LCoS technology,{{Fact|date=September 2007}}. Sony and JVC also produce and market front-projection displays that use three LCoS panels. Direct-view LCoS devices such as the single-panel LED-illuminated devices made by Displaytech and Forth Dimension Displays (Dalgety Bay, Fife, Scotland) (formerly known as CRLO Displays) are also used as electronic viewfinders for digital cameras and within Near to Eye (NTE) applications such as [[Head-mounted display|Head Mounted Displays (HMDs)]]. These devices are made using ferroelectric liquid crystals, which are inherently faster than other types of liquid crystals. Developers and manufacturers of LCoS panels who are now defunct, or have exited LCoS, include: Philips, Microdisplay Corporation, Spatialight, Syntax-Brillian. == Display system architectures == There are two broad categories of LCoS displays: three-panel and single-panel. In three-panel designs, there is one display chip per color, and the images are combined optically. In single-panel designs, one display chip shows the red, green, and blue components in succession with the observer's eyes relied upon to combine the color stream. As each color is presented, a color wheel (or an RGB [[LED]] array) illuminates the display with only red, green or blue light. If the frequency of the color fields is lower than about 540 Hz, an effect called color breakup is seen, where false colors are briefly perceived when either the image or the observer's eye is in motion. While less expensive; single-panel projectors require higher-speed display elements to process all three colors during a single frame time, and the need to avoid color breakup makes further demands on the speed of the display technology. === Three-panel designs === In a [[DLP]] device the light is separated into three components and then combined back: Two [[beam splitter]]s are needed. In LCoS devices the light is additionally [[polarized]] and then analyzed; four beam splitters are needed. In most DLP sets 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. === One-panel designs === There were three single-panel LCoS displays in production. One by [[Philips]], one by Microdisplay Corporation and one from Forth Dimension Displays. Forth Dimension Displays have a Ferroelectric LCoS display technology (known as TDI) (available in SXGA and 720P resolutions) which is mainly, but not exclusively, used in high resolution NTE applications such as Training & Simulation. == See also == * [[Comparison of display technology]] * [[DLP]] * [[SXRD]] == External links == * Biever, Celeste. [http://www.newscientist.com/news/news.jsp?id=ns99994550 'Intel inside' comes to flat panel TVs] (January 9, 2004 - No longer planned for development) ''NewScientist.com''. * [http://www.pcworld.com/news/article/0,aid,118088,00.asp contrast vs brightness] * [http://www.spatialight.com/Technology/lcos_explained.htm LCOS Technology Explained], SpatiaLight, Inc. * [http://www.jvc-victor.co.jp/english/pro/dila/feature.html D-ILA Technology Explained], JVC * [http://www.displaytech.com/history_1992-present.html "Display Technologies" 1992 to Present], Displaytech Inc. * [http://www.holoeye.com/lcos_microdisplays.html LCoS displays] Holoeye Photonics AG. * [http://www.forthdd.com/ LCoS displays] Forth Dimension Displays. * [http://www.hardwaresecrets.com/article/544 Everything You Need to Know About TV Technologies] {{Display Technology}} [[Category:Display technology]] [[Category:Silicon]] [[ca:Cristall líquid sobre silici]] [[de:LCoS]] [[es:Cristal líquido sobre silicio]] [[fr:LCOS]] [[ja:LCOS]] [[zh:液晶覆硅]]