https://vrarwiki.com/index.php?action=history&feed=atom&title=Liquid_crystal_on_siliconLiquid crystal on silicon - Revision history2026-04-07T05:32:21ZRevision history for this page on the wikiMediaWiki 1.43.0https://vrarwiki.com/index.php?title=Liquid_crystal_on_silicon&diff=36194&oldid=prevRealEditor: Copy from https://www.xvrwiki.org/wiki/Liquid_crystal_on_silicon2025-07-02T20:12:49Z<p>Copy from https://www.xvrwiki.org/wiki/Liquid_crystal_on_silicon</p>
<p><b>New page</b></p><div>'''Liquid crystal on silicon''' ('''LCOS''') is a type of manufacturing process for making microdisplays and [[SLM]]s.<br />
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Liquid crystal on silicon (LCoS or LCOS) is a miniaturized reflective active-matrix liquid-crystal display or "[[microdisplay]]" using a layer of [[liquid crystal]] on top of a silicon backplane. It is a type of [[spatial light modulator]]. LCoS initially was developed for projection televisions, but has since been used in near-eye displays.<br />
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LCOS phase only SLMs operate on the principle of the [[birefringence]] of the liquid crystal material.<br />
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== Construction ==<br />
===Layers===<br />
An LCOS module is layered.<br />
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The first layer is the top layer. It is the counter electrode (CE). It is made of a standard glass (such as [[Corning 1737F]]) covered by a layer of [[indium tin oxide]] (ITO).<ref>https://tfcg.elis.ugent.be/publi/docvdsteen/docvdsteen.pdf Page 46</ref><br />
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There is a top layer of ITO and a bottom layer of ITO. Between them is the liquid crystal. Underneath the bottom layer of ITO is a [[CMOS backplane]].<br />
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===Parameters===<br />
The counter electrode glass must have a thermal expansion coefficient that matches the backplane's as closely as possible.<br />
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The liquid crystal material used in LCOS gadgets is typically a nematic liquid crystal.<br />
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The distance from the backplane to the glass substrate may be around 2 microns.<br />
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== Manufacturing ==<br />
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Manufacturing of LCOS gadgets can be separated from the process of etching the silicon.<br />
A manufacturing facility may be able to receive pre-etched and pixelated backplane CMOS wafers from a fab. Then the facility can simply fill the liquid crystal, do layer alignment, and packaging.<br />
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=== Inputs ===<br />
The inputs to the manufacturing process are:<br />
* CMOS silicon wafers with a TFT pattern etched into them<br />
* cover glass wafers<br />
* indium tin oxide<br />
* liquid crystal<br />
* polyamide or inorganic material for an alignment layer<br />
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The CMOS silicon wafers already have CMOS patterns in them.<br />
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The CMOS silicon wafer is known as a backplane.<br />
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=== Steps ===<br />
* Liquid crystal fill and seal<br />
* Electrode attachment<br />
* Packaging<br />
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== History ==<br />
Some of the first LCOS modulators were made at Hughes Research Laboratories.<br />
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== Display product companies ==<br />
* [[Forth Dimension Displays]]<br />
* [[Kopin]]<br />
* [[Holoeye]]<br />
* [[CamOptics]]<br />
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== Silicon foundries ==<br />
* Amkor<ref>https://tfcg.elis.ugent.be/publi/docvdsteen/docvdsteen.pdf Page 61</ref><br />
* SMIC<br />
* TSMC<br />
* UMC<br />
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==References==<br />
{{Reflist}}<br />
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[[Category:Electronics manufacturing]]</div>RealEditor