{{short description|Screen technology used for liquid crystal displays}} {{Use dmy dates|date=July 2024}} {{multiple issues | {{more citations needed|date=October 2013}} {{original research|date=October 2013}} }} '''In-plane switching''' ('''IPS''') is a screen technology used for liquid-crystal displays (LCDs). In IPS, liquid crystal molecules are sandwiched between, and aligned parallel to, two panels (planes) of glass substrate. The molecules are reoriented by applying electric field, while remaining essentially parallel to the surfaces to produce an image.{{Clarify|date=February 2026}} It was designed to remedy issues of poor viewing angle and color reproduction of the twisted nematic field effect (TN) matrix LCDs prevalent in the late 1980s.<ref name="DDExplained">{{cite web|last=Cross|first=Jason|date=18 March 2012|title=Digital Displays Explained|url=http://www.techhive.com/article/251988/digital_true_explained.html?page=4|url-status=live|archive-url=https://web.archive.org/web/20150402131332/http://www.techhive.com/article/251988/digital_displays_explained.html?page=4|archive-date=2 April 2015|access-date=19 March 2015|work=TechHive|publisher=PC World|page=4}}</ref>
== History == Computer monitors started utilizing active matrix TFT LCD panels in the 1980s and early 1990s, as an alternative technology to the cathode ray tube. These early LCD displays suffered from inverted grayscale, loss of contrast and color reproduction accuracy when viewed from extreme angles,<ref>{{cite web |title=TFT Technology: Enhancing the viewing angle |url=https://riverdi.com/technology/#technology-Angle |publisher=Riverdi (TFT Module Manufacturer) |access-date=5 November 2016 |archive-url=https://web.archive.org/web/20160423135213/http://riverdi.com/technology#technology-Angle |archive-date=23 April 2016 |quote=However, [twisted nematic] suffers from the phenomenon called gray scale inversion. This means that the display has one viewing side in which the image colors suddenly change after exceeding the specified viewing angle.}} (see image [https://riverdi.com/wp-content/uploads/2016/02/g_inversion.png Inversion Effect])</ref> and had significant display motion blur due to poor response time. IPS and vertical alignment (VA) are designed to alleviate these issues.
An early experimental IPS-LCD is described in a 1974 patent. It used inter-digitated electrodes on only one glass substrate, to produce electric field essentially parallel to the glass substrates.<ref>{{cite web |url=http://worldwide.espacenet.com/publicationDetails/biblio?locale=en_EP&CC=US&NR=3834794 |title=Bibliographic data: US3834794 (A) ― 1974-09-10 |website=Espacenet.com |access-date=9 October 2013 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308185719/https://worldwide.espacenet.com/publicationDetails/biblio?locale=en_EP&CC=US&NR=3834794 |url-status=dead }}</ref><ref>{{US Patent|3834794}}: R. Soref, ''Liquid crystal electric field sensing measurement and display device'', filed 28 June 1973.</ref> However, the inventor was not able to implement IPS-LCDs with superior quality to contemporary TN displays.
After thorough analysis, details of advantageous molecular arrangements were filed in Germany by Guenter Baur et al. and patented in various countries including the US on 9 January 1990.<ref>{{cite web |url=http://worldwide.espacenet.com/publicationDetails/biblio?locale=en_EP&CC=US&NR=5576867 |title=Bibliographic data: US5576867 (A) ― 1996-11-19 |website=Espacenet.com |access-date=9 October 2013 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308002522/https://worldwide.espacenet.com/publicationDetails/biblio?locale=en_EP&CC=US&NR=5576867 |url-status=dead }}</ref><ref>{{patent|US|5576867|patent|title=G. Baur, W. Fehrenbach, B. Staudacher, F. Windscheid, R. Kiefer, ''Liquid crystal switching elements having a parallel electric field and beta o which is not 0 or 90 degrees'', filed 9 January 1990}}</ref> The Fraunhofer Society in Freiburg, where the inventors worked, assigned these patents to Merck KGaA, Darmstadt, Germany.
Shortly thereafter, Hitachi of Japan filed patents on improvements to the technology.<ref>{{cite web |url=http://informationdisplay.org/IDArchive/2014/MarchApril/HonorsandAwards.aspx |title=2014 SID Honors and Awards |website=InformationDisplay.org |access-date=4 July 2014 |archive-url=https://web.archive.org/web/20140416002430/http://informationdisplay.org/IDArchive/2014/MarchApril/HonorsandAwards.aspx |archive-date=16 April 2014 }}</ref> In 1992, engineers at Hitachi worked out various practical details of the IPS technology to interconnect the thin-film transistor array as a matrix and to avoid undesirable stray fields in between pixels.<ref>{{cite web |url=http://worldwide.espacenet.com/publicationDetails/biblio?locale=en_EP&CC=US&NR=5598285 |title=Espacenet{{Snd}} Bibliographic data |website=Worldwide.espacenet.com |date=28 January 1997 |access-date=15 August 2014 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308044710/https://worldwide.espacenet.com/publicationDetails/biblio?locale=en_EP&CC=US&NR=5598285 |url-status=dead }}</ref><ref>{{US Patent|5598285}}: K. Kondo, H. Terao, H. Abe, M. Ohta, K. Suzuki, T. Sasaki, G. Kawachi, J. Ohwada, ''Liquid crystal display device'', filed 18 September 1992 and 20 January 1993.</ref> Hitachi also improved the viewing angle dependence further by optimizing the shape of the electrodes (''Super IPS''). NEC and Hitachi became early manufacturers of active-matrix addressed LCDs based on the IPS technology. This is a milestone for implementing large-screen LCDs having acceptable visual performance for flat-panel computer monitors and television screens. In 1996, Samsung developed the optical patterning technique that enables multi-domain LCD. Multi-domain and in-plane switching subsequently remain the dominant LCD designs through 2006.<ref>{{Cite news|url=http://www.nature.com/nature/journal/v382/n6593/pdf/382666c0.pdf |title=Optical Patterning |publisher=Nature |date=22 August 1996 |access-date=13 June 2008}}</ref>
Later, LG Display and other South Korean, Japanese, and Taiwanese LCD manufacturers adopted IPS technology.
IPS technology is widely used in panels for TVs, tablet computers, and smartphones. In particular, most IBM products marketed as ''Flexview'' from 2004 to 2008 have IPS LCDs with CCFL backlighting, and all Apple Inc. products marketed with the label ''Retina Display''<ref>[https://www.apple.com/iphone-5c/specs/ Technical specifications iPhone 5c] {{webarchive|url=https://web.archive.org/web/20131031105000/https://www.apple.com/iphone-5c/specs/ |date=31 October 2013 }}</ref><ref>[https://www.apple.com/ipad/compare/#comparison-chart Comparison of iPad models] {{webarchive|url=https://web.archive.org/web/20121024015359/http://www.apple.com/ipad/compare/ |date=24 October 2012 }}</ref> feature IPS LCDs with LED backlighting since 2010.
{| class="wikitable" style="font-size: 90%; text-align:left;" |+ Hitachi IPS technology development<ref>[http://www.ips-alpha.co.jp/en/technology/ips.html IPS-Pro (Evolving IPS technology)] {{webarchive|url=https://web.archive.org/web/20100329145251/http://www.ips-alpha.co.jp/en/technology/ips.html |date=29 March 2010 }}</ref><ref>{{cite web |url=http://www.barco.be/barcoview/downloads/IPS-Pro_LCD_technology.pdf |title=Archived copy |access-date=24 November 2013 |archive-url=https://web.archive.org/web/20121115091442/http://www.barco.be/barcoview/downloads/IPS-Pro_LCD_technology.pdf |archive-date=15 November 2012 }}</ref> |- ! style="width:12%;"| Name ! Nickname ! Year ! style="width:12%;"| Advantage ! Transmittance or<br />contrast ratio ! Remarks |- | Super TFT || IPS || 1996 || Wide viewing angle || 100/100<br />Base level || Most panels also support true 8-bit-per-channel colour. These improvements came at the cost of a lower response time, initially about 50 ms. IPS panels were also extremely expensive. |- | Super-IPS || S-IPS || 1998 || Colour shift free || 100/137 || IPS has since been superseded by '''S-IPS''' (Super-IPS, Hitachi in 1998), which has all the benefits of IPS technology with the addition of improved pixel refresh timing.{{quantify|date=September 2014}} |- | Advanced Super-IPS || AS-IPS || 2002 || High transmittance || 130/250 || AS-IPS, also developed by Hitachi in 2002, improves substantially{{quantify|date=September 2014}} on the contrast ratio of traditional S-IPS panels to the point where they are second only to some S-PVAs.{{citation needed|date=September 2014}} |- | IPS-Provectus || IPS-Pro || 2004 || High contrast ratio || 137/313 || The latest panel from IPS Alpha Technology with a wider colour gamut{{quantify|date=September 2014}} and contrast ratio{{quantify|date=September 2014}} matching PVA and ASV displays without off-angle glowing.{{citation needed|date=September 2014}} |- | IPS Alpha || IPS-Pro || 2008 || High contrast ratio || || Next generation of IPS-Pro |- | IPS Alpha Next-Gen || IPS-Pro || 2010 || High contrast ratio || || |}
{| class="wikitable" style="font-size: 90%; text-align:left;" |+ LG IPS technology development |- ! style="width:15%;"| Name ! Nickname ! Year ! Remarks |- | Horizontal IPS || H-IPS || 2007 || Improves{{quantify|date=January 2012}} contrast ratio by twisting electrode plane layout. Also introduces an optional Advanced True White polarizing film from NEC, to make white look more natural{{quantify|date=January 2012}}. This is used in professional/photography LCDs.{{Citation needed|date=January 2012}} |- | Enhanced IPS || E-IPS || 2009 || Wider{{quantify|date=January 2012}} aperture for light transmission, enabling the use of lower-power, cheaper backlights. Improves{{quantify|date=January 2012}} diagonal viewing angle and further reduce response time to 5 ms.{{Citation needed|date=January 2012}} |- | Professional IPS || P-IPS || 2010 || Offer 1.07 billion colours (30-bit colour depth).{{Citation needed|date=January 2012}} More possible orientations per sub-pixel (1024 as opposed to 256) and produces a better{{quantify|date=January 2012}} true colour depth. |- | Advanced High Performance IPS || AH-IPS || 2011 || Improved colour accuracy, increased resolution and PPI, and greater light transmission for lower power consumption.<ref>{{cite web |author=tech2 News Staff |url=http://tech.firstpost.com/news-analysis/lg-announces-super-high-resolution-ah-ips-displays-19506.html |title=LG Announces Super High Resolution AH-IPS Displays |date=19 May 2011 |website=Firstpost.com |access-date=10 December 2015 |url-status=live |archive-url=https://web.archive.org/web/20151211104520/http://tech.firstpost.com/news-analysis/lg-announces-super-high-resolution-ah-ips-displays-19506.html |archive-date=11 December 2015 }}</ref> |}
== Technology ==
thumb|300px|Schematic diagram IPS liquid crystal display
===Implementation=== In this case, both linear polarizing filters P and A have their axes of transmission in the same direction. To obtain the 90 degree twisted nematic structure of the LC layer between the two glass plates without an applied electric field (''OFF'' state), the inner surfaces of the glass plates are treated to align the bordering LC molecules at a right angle. This molecular structure is practically the same as in TN LCDs. However, the arrangement of the electrodes e1 and e2 is different. Electrodes are in the same plane and on a single glass plate, so they generate an electric field essentially parallel to this plate. The diagram is not to scale: the LC layer is only a few micrometers thick, very thin compared with the distance between the electrodes.
The LC molecules have a positive dielectric anisotropy and align themselves with their long axis parallel to an applied electrical field. In the ''OFF'' state (shown on the left), entering light L1 becomes linearly polarized by polarizer P. The twisted nematic LC layer rotates the polarization axis of the passing light by 90 degrees, so that ideally no light passes through polarizer A. In the ''ON'' state, a sufficient voltage is applied between electrodes and a corresponding electric field E is generated that realigns the LC molecules as shown on the right of the diagram. Here, light L2 can pass through polarizer A.
In practice, other schemes of implementation exist with a different structure of the LC molecules{{Snd}}for example without any twist in the ''OFF'' state. As both electrodes are on the same substrate, they take more space than TN matrix electrodes. This also reduces contrast and brightness.<ref name="techs" />
[[File:Wiki dell lcd.jpg|thumb|300px| This pixel layout is found in S-IPS LCDs. A chevron shape is used to widen the viewing cone.]]
=== Advantages === * IPS panels display consistent, accurate color from all viewing angles.<ref>[http://www.ipslcd.com/en/front/home/main.jsp Comparisons done by LG Display] {{webarchive|url=https://web.archive.org/web/20130113080608/http://www.ipslcd.com/en/front/home/main.jsp |date=13 January 2013 }}</ref> A comparison in 2014 of IPS vs. TN panels concerning color consistency under different viewing angles can be seen on the website of Japan Display Inc.<ref name=JDI>[http://www.j-display.com/english/technology/jdilcd/pictureq.html Visual comparison of IPS and TN done by Japan Display Inc.] {{webarchive|url=https://web.archive.org/web/20140328230635/http://www.j-display.com/english/technology/jdilcd/pictureq.html |date=28 March 2014 }}</ref> Also, compared to TN panels, IPS panels can display more color spaces. * Unlike TN LCDs, IPS panels do not lighten or show tailing when touched. This is important for touch-screen devices, such as smartphones and tablet computers.<ref>[http://www.lgdisplay.com/eng/product/technology/IPS IPS "Stable Panel"] {{webarchive|url=https://web.archive.org/web/20150502194224/http://www.lgdisplay.com/eng/product/technology/IPS |date=2 May 2015 }}</ref> * IPS panels offer clear and razor-sharp images without reflections, a wide viewing range, stable response time and better coloring.<ref>{{Cite web |title=Panel Mount Monitors {{!}} 7 to 27 inches {{!}} Beetronics |url=https://www.beetronics.com/open-frame-panel-mount-monitors |access-date=21 October 2023 |website=beetronics.com}}</ref><ref name=techs>{{cite web|url=http://www.tftcentral.co.uk/articles/panel_technologies.htm|title=Panel Technologies: TN Film, MVA, PVA and IPS Explained|first=Simon|last=Baker|date=30 April 2011|publisher=Tftcentral.co.uk|access-date=13 January 2012|url-status=live|archive-url=https://web.archive.org/web/20170629182048/http://www.tftcentral.co.uk/articles/panel_technologies.htm|archive-date=29 June 2017}}</ref>{{unreliable source?|date=October 2012|reason=Anonymous site, no editorial staff, united elsewhere, unestablished author}}<ref>{{cite web|url=https://www.esportsource.net/monitors/ips-tn-panel/|title=IPS or TN panel? |first=Winston|last=Mark|date=30 June 2021|publisher=EsportSource.net|access-date=7 February 2022}}</ref>
=== Disadvantages === Compared to TN displays, IPS ones may consume more power, cost more to manufacture, have slower response times, and suffer from uneven backlight brightness ("backlight bleeding") more easily.<ref>{{cite web |last1=Ivankov |first1=Alex |title=Advantages and disadvantages of IPS screen technology |url=http://www.versiondaily.com/advantages-and-disadvantages-of-ips-screen-technology/ |website=Version Daily |access-date=25 September 2017 |date=1 September 2016 |url-status=dead |archive-url=https://web.archive.org/web/20170926041030/http://www.versiondaily.com/advantages-and-disadvantages-of-ips-screen-technology/ |archive-date=26 September 2017}}</ref><ref>{{cite web|title=Display and Graphics Guide|date=3 May 2017 |url=https://www.isc.upenn.edu/how-to/display-and-graphics-guide|access-date=14 February 2019|publisher=The University of Pennsylvania}}</ref>
===Other names=== Samsung Electronics's use the marketing term Super PLS (Plane-to-Line Switching) to refer to IPS panel technologies with similar features and performance characteristics to LG's offering.<ref name="IPS">{{cite web|title=Samsung Adopts IPS instead of AMOLED: Why?| date=9 November 2012 |url=http://www.seoul.co.kr/news/newsView.php?id=20121109023018&spage=1/|publisher=Seoul Shinmun|access-date=9 November 2012|url-status=live|archive-url=https://web.archive.org/web/20121221112303/http://www.seoul.co.kr/news/newsView.php?id=20121109023018&spage=1%2F|archive-date=21 December 2012}}</ref><ref name="PLS">{{cite web|title=Samsung PLS improves on IPS displays like iPad's, costs less|url=http://www.electronista.com/articles/10/12/01/samsung.intros.pls.as.improvement.on.lcds/|publisher=electronista.com|access-date=30 October 2012|url-status=live|archive-url=https://web.archive.org/web/20121027053321/http://www.electronista.com/articles/10/12/01/samsung.intros.pls.as.improvement.on.lcds|archive-date=27 October 2012}}</ref>
== See also == * Computer monitor * e-paper * LCD TV * Liquid-crystal display * Smart watch * TFT LCD
== References == {{Reflist}}
== External links == {{Commons category}} * [http://www.tftcentral.co.uk/articles/panel_technologies.htm Panel Technologies] * [https://displaybenchmark.com/va-vs-ips/ IPS vs. VA Panel] * [https://www.ipsfullform.in/ips-full-form-in-display/ Full Form of IPS Display] {{Webarchive|url=https://web.archive.org/web/20190804123940/https://www.ipsfullform.in/ips-full-form-in-display/ |date=4 August 2019 }}
{{Display technology}}
{{DEFAULTSORT:Ips Panel}} Category:Display technology Category:Liquid crystal displays Category:German inventions Category:Japanese inventions Category:South Korean inventions