A Beginner's Guide to the Technology Behind IPS Display

IPS is an acronym for in-plane switching, which is a screen technology that is used with LCD screens. In-plane switching was designed to address limitations in the LCD screens of the late 1980s that used a twisted nematic field effect matrix. The TN method was the only technology available at the time for active matrix TFT (Thin Film Transistor) LCDs. The main limitations of the twisted nematic field effect matrix LCDs are low-quality color and a narrow viewing angle. IPS-LCDs deliver better color reproduction and wider viewing angles.

IPS-LCDs are commonly used on midrange and high-end smartphones and portable devices. All Retina Display Apple iPhones feature IPS-LCDs, as does the Motorola Droid and some TVs and tablets.

Information on IPS Displays

IPS-LCDs feature two transistors for each pixel, whereas TFT-LCDs use just one. This requires a more powerful backlight, which delivers more accurate colors and lets the screen be viewed from a wider angle.

IPS-LCDs don't show when the screen has been touched, which you might notice in some older monitors. This is particularly advantageous for touch-screen displays like those on smartphones and touch-screen laptops.

The downside is that an IPS-LCD consumes more power than a TFT-LCD, possibly up to 15 percent more. They're also more expensive to make and have longer response times.

IPS Advances in Technology

IPS has gone through a number of developmental phases within Hitachi and LG Display.

• Hitachi widened the viewing angle with Super TFT (IPS) in 1996.
• It also released Super-IPS (S-IPS) in 1998 to remove color shifting.
• In 2001, Advanced Super-IPS (AS-IPS) improved transmittance from 100/100 (in 1996) to 130/250.
• Hitachi improved the contrast ratio in 2004, 2008 and 2010 with the releases of IPS-Provectus, IPS Alpha, and IPS Alpha next gen.

LG Display's IPS technology timeline looks like this:

• Contrast ratio was improved in 2007 with Horizontal IPS (H-IPS).
• Enhanced IPS (E-IPS) improved the viewing angle and reduced the response time to five milliseconds, while also widening the aperture for light transmission. It was released in 2009.
• 2010 saw Professional IPS (P-IPS), which offered more than a billion colors and more orientations per pixel. IPS-Pro is highly advanced and expensive. 
• LG Display released Advanced High-Performance IPS (AH-IPS) in 2011 to improve color accuracy, increase the resolution, and provide more light when in lower power mode.

IPS Alternatives

Samsung introduced Super PLS (Plane-to-Line Switching) in 2010 as an alternative to IPS. It's similar to IPS but with the added benefits of a better viewing angle, a brightness increase of 10 percent, a flexible panel, better image quality, and a 15 percent lower cost than IPS-LCDs.

In 2012, AHVA (Advanced Hyper-Viewing Angle) was introduced by AU Optronics to provide an IPS alternative that featured IPS-like panels but with higher refresh rates.