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{{short description|Micro projection technology}}
The
<!-- Image with unknown copyright status removed: [[Image:6ribbons GLV.JPG|300 px|thumb|Figure1: The GLV Device with alternate ribbons deflected to form a dynamic diffraction grating]] -->
Silicon Light Machines (SLM), in Sunnyvale CA, markets and licenses GLV technology with the capitalised trademarks "'Grated Light Valve'" and GLV, previously Grating Light Valve.<ref>{{Cite web|quote=our patented Grated Light Valve (GLV) modules|url=http://www.siliconlight.com/htmlpgs/homeset/homeframeset.html|title=Home page|publisher=Silicon Light Machines|
==Brief history==
The light valve was initially developed at [[Stanford University]], in California, by electrical engineering professor [[David M. Bloom]], along with [[William Banyai|William C. Banyai]], Raj Apte, Francisco Sandejas, and [[Olav Solgaard]], professor in the [[Stanford Department of Electrical Engineering]]. In 1994, the start-up company [[Silicon Light Machines]] was founded by Bloom to develop and commercialize the technology. Cypress Semiconductor acquired Silicon Light Machines in 2000 and sold the company to Dainippon Screen. Before the acquisition by Dainippon Screen, several marketing articles were published in EETimes, EETimes China, EETimes Taiwan, Electronica Olgi, and Fibre Systems Europe, highlighting Cypress Semiconductor's new MEMS manufacturing capabilities. The company is now wholly owned by Dainippon Screen Manufacturing Co., Ltd.<ref>[http://www.screen.co.jp/press/NR080702E.pdf Dainippon Screen Mfg. Co., Ltd.]</ref>
In July 2000, [[Sony]] announced the signing of a technology licensing agreement with SLM<ref>[http://www.sony.net/SonyInfo/News/Press_Archive/200206/02-023E/ Sony Develops a Grating Light Valve display device that gives high resolution, excellent contrast ratio and wide color reproduction]</ref><ref>{{Cite web |url=http://meko.co.uk/glv.shtml |title=Sony Signs Technology License Agreement with SLM |access-date=2010-02-03 |archive-url=https://web.archive.org/web/20100120030238/http://www.meko.co.uk/glv.shtml |archive-date=2010-01-20
SLM then partnered with [[Evans & Sutherland]] (E&S). Using GLV technology, E&S developed the E&S Laser Projector, designed for use in domes and planetariums.<ref>{{Cite web |url=http://www.es.com/products/digital_theater/digistar3-laser.asp |title=Digistar 3 Laser |access-date=2009-02-03 |archive-date=2009-01-16 |archive-url=https://web.archive.org/web/20090116183836/http://www.es.com/products/digital_theater/digistar3-laser.asp
== Technology ==
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<!-- Image with unknown copyright status removed: [[Image:Different wavelength deflection.gif|thumb|500 px|Figure2:example of application of different wavelength deflection]] -->
The GLV device is built on a silicon [[wafer]] and consists of parallel rows of "'highly reflective micro-ribbons'" – ribbons of sizes of a few
The ribbons and the substrate are electrically conductive so that the [[Electrostatic deflection (structural element)|deflection]] of the ribbon can be controlled in an analog manner: When the voltage of the active ribbons is set to ground potential, all ribbons are undeflected, and the device acts as a mirror so the incident light returns along the same path. When a voltage is applied between the ribbon and base conductor, an electrical field is generated and deflects the active ribbon downward toward the substrate. This deflection can be as big as one-quarter wavelength hence creating diffraction effects on incident light that is reflected at an angle that is different from that of the incident light. The wavelength to diffract is determined by the spatial frequency of the ribbons. As this spatial frequency is determined by the photolithographic mask used to form the GLV device in the [[CMOS]] fabrication process, the departure angles can be very accurately controlled, which is useful for optical switching applications.
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=== Displays ===
To build a display system using the GLV device, different approaches can be followed: ranging from a simple process using a single GLV device with white light as a source, thus having a [[monochrome]] system, to a more complex solution using three different GLV devices each for one of the RGB primaries' sources that once diffracted require additional optical filters to point the light onto the screen or an intermediate using a single white source with a GLV device.
Besides, the light can be diffracted by the GLV device into an eyepiece for [[virtual retinal display]] or into an optical system for image projection onto a screen ([[Video projector|projector]] and [[Rear-projection television|rear-projector]]).<ref>Teklas S. Perry. ''Tomorrow's TV'', ''[[IEEE Spectrum]]'', April 2004. </ref><ref>{{Cite web |url=http://www.siliconlight.com/webpdf/SPIE%20Jan04%20SLM%20WrtEng%205348-5%20.pdf |title=Jahja I. Trisnadi, Clinton B. Carlisle, Robert Monteverde. "Overview and Applications of Grating Light Valve-based optical write engines for high-speed digital imaging", January 26, 2004. |access-date=February 25, 2010 |archive-url=https://web.archive.org/web/20081010015714/http://www.siliconlight.com/webpdf/SPIE%20Jan04%20SLM%20WrtEng%205348-5%20.pdf |archive-date=October 10, 2008
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=== Computer to plate printing ===
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