IPS (in-plane switching) is a screen technology for liquid-crystal displays (LCDs). It was designed to solve the main limitations of the twisted nematic field effect (TN) matrix LCDs which were prevalent in the late 1980s. These limitations included strong viewing angle dependence and low-quality color reproduction. In-plane switching involves arranging and switching the orientation of the molecules of the liquid crystal (LC) layer between the glass substrates. This is done, essentially, parallel to these glass plates.
1 History 2 Technology
2.1 Implementation 2.2 Advantages 2.3 Disadvantages
3 IPS Alternative Technologies
3.1 Plane to Line Switching (PLS) 3.2 Advanced Hyper-Viewing Angle (AHVA)
4 Manufacturers 5 See also 6 References 7 External links
The TN method was the only viable technology for active matrix TFT
LCDs in the late 1980s and early 1990s. Early panels showed grayscale
inversion from up to down, and had a high response time (for this
kind of transition, 1 ms is visually better than 5 ms). In the
mid-1990s new technologies were developed—typically IPS and Vertical
Alignment (VA)—that could resolve these weaknesses and were applied
to large computer monitor panels.
One approach patented on October 14, 1996 was to use inter-digitated
electrodes on one glass substrate only to produce an electric field
essentially parallel to the glass substrates. However, the
inventor was not yet able to implement such IPS-LCDs superior to TN
After thorough analysis, details of advantageous molecular
arrangements were filed in
Name Nickname Year Advantage Transmittance/ contrast ratio Remarks
Super TFT IPS 1996 Wide viewing angle 100/100 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.
Colour shift free
IPS has since been superseded by S-IPS (Super-IPS,
AS-IPS, also developed by
IPS-Provectus IPS-Pro 2004 High contrast ratio 137/313 The latest panel from IPS Alpha Technology with a wider colour gamut[quantify] and contrast ratio[quantify] matching PVA and ASV displays without off-angle glowing.
IPS alpha IPS-Pro 2008 High contrast ratio
Next generation of IPS-Pro
IPS alpha next gen IPS-Pro 2010 High contrast ratio
LG IPS technology development
Name Nickname Year Remarks
Horizontal IPS H-IPS 2007 Improves[quantify] 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]. This is used in professional/photography LCDs.
Enhanced IPS E-IPS 2009 Wider[quantify] aperture for light transmission, enabling the use of lower-power, cheaper backlights. Improves[quantify] diagonal viewing angle and further reduce response time to 5ms.
Professional IPS P-IPS 2010 Offer 1.07 billion colours (30-bit colour depth). More possible orientations per sub-pixel (1024 as opposed to 256) and produces a better[quantify] 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.
Schematic diagram IPS LC 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. Because they are in the same plane and on a single glass plate, 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 and so is very small 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 electrical 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 - 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. Super-IPS was later introduced with better response times and colour reproduction.
This pixel layout is found in S-IPS LCDs. A chevron shape is used to widen the viewing cone.
IPS panels display consistent, accurate colour from all viewing
angles. A state-of-the-art (2014) comparison of IPS vs. TN panels
concerning colour consistency under different viewing angles can be
seen on the website of
IPS panels require up to 15% more power than TN panels. IPS panels are more expensive to produce than TN panels. IPS panels have longer response time than TN panels.
IPS Alternative Technologies
This section needs expansion. You can help by adding to it. (May 2011)
Plane to Line Switching (PLS)
Towards the end of 2010
Further improvement in viewing angle 10 percent increase in brightness Up to 15 percent decrease in production costs Increased image quality Flexible panel
Advanced Hyper-Viewing Angle (AHVA)
Computer monitor e-paper LCD TV TFT LCD Smart watch
^ a b Cross, Jason (18 March 2012). "Digital Displays Explained".
TechHive. PC World. p. 4. Archived from the original on 2 April
2015. Retrieved 19 March 2015.
^ "TFT Technology: Enhancing the viewing angle". Riverdi (TFT Module
Manufacturer). Archived from the original on 23 April 2016. Retrieved
5 November 2016. 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 Inversion
^ "Bibliographic data: US3834794 (A) ― 1974-09-10". Espacenet.com.
Retrieved 9 October 2013.
^ U.S. Patent 3,834,794: R. Soref,
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