IPS Technology
In-Plane Switching (IPS) technology controls the orientation of liquid crystals within an LCD. When voltage is applied, the liquid crystals rotate parallel to the display plane (in-plane), rather than standing upright. This parallel alignment allows light to pass through more efficiently, enhancing several key display characteristics.
Compared to traditional Twisted Nematic (TN) panels, IPS displays offer superior colour accuracy and much wider viewing angles. Additionally, thanks to their high brightness levels, many IPS-based TFTs are readable even in direct sunlight.
How It Works
In the animation above, both linear polarising filters are aligned with their transmission axes in the same direction. To achieve the 90-degree twisted nematic configuration of the liquid crystal layer (in the OFF state), the inner surfaces of the glass substrates are treated to align adjacent liquid crystal molecules at right angles to one another. Because the electrodes are positioned in the same plane on a single glass substrate, they create an electric field that runs parallel to the glass.
The liquid crystal molecules, which have a positive dielectric anisotropy, align their long axis in the direction of the electric field when voltage is applied. In the OFF state, incident light first passes through a polariser and becomes linearly polarised. The twisted nematic structure of the liquid crystal layer then rotates the light’s polarisation by 90 degrees, ideally preventing it from passing through the second polariser.
In the ON state, a sufficient voltage is applied across the electrodes, generating an electric field that realigns the liquid crystal molecules. This prevents the light from being rotated, allowing it to pass through the second polariser and become visible to the viewer