IPS, In-Plane Switching

What is IPS? And why does it matter? IPS stands for In-Plane Switching. According to Wikipedia:

In-plane switching was developed by Hitachi Ltd. in 1996 to improve on the poor viewing angle and the poor color reproduction of TN panels at that time. Its name comes from the main difference from TN panels, that the crystal molecules move parallel to the panel plane instead of perpendicular to it. This change reduces the amount of light scattering in the matrix, which gives IPS its characteristic wide viewing angles and good color reproduction.

TN-based LCD panels still have relatively poor viewing angles and that means rapid color degradation when viewing the display from anywhere but center. IPS, in my opinion, is the best LCD technology for those who need color accuracy on their displays. That’s one of the reasons why Apple continues to put IPS panels into their high-end systems (iPhone 4, iPad, iMacs, Cinema displays), except for its notebook PCs (MacBook Air, MacBook, MacBook Pro).

There might be a reason for this. Liquid crystals in an IPS LCD panel twists on a horizontal plane with an electrical field that is applied through each end of the crystal. This design requires two transistors for each pixel. Transistors are not transparent and blocks light, reducing light transmittance. To compensate the brightness level needs to be increased leading to more power consumption. This used to be true.

With Enhanced IPS or E-IPS the aperture has been increased, meaning the transistor portion of the panel has been made smaller. This redesign increases light transmittance allowing for a lower-power backlight.

There are several LCD manufacturers that are producing IPS panels today but the largest by far is LG Display (LGD) based in South Korea. LGD has worked closely with Apple for quite some time. The most advanced IPS is called Professional IPS or P-IPS manufactured by LGD. P-IPS refers to a 10-bit LCD panel that can reproduce 1.07 billion colors.

Portable gadgets like the iPhone 4, the iPad, and the Samsung Galaxy Tab will continue to grab attention from a population that wants portable computing with them wherever they are. The display makes up a large portion of a mobile device and its success increasingly depends on the performance of the display. That performance in turn is based on touch responsiveness, color fidelity at all viewing angles, brightness, sunlight readability, etc.

These requirements play right into the strengths of IPS LCD technology. In my opinion IPS will rule in tablets and eventually in notebook PCs, monitors and TVs. Although Samsung has been vying for supremacy in LCD manufacturing with its PVA (Patterned Vertical Alignment) technology, the company has recently licensed intellectual property from Hydis and Hitachi to manufacture IPS LCD panels to supply Apple. In the smartphone space IPS will compete fiercely with OLED technology, especially from Samsung with its Super AMOLED.