LCD Shielding (EMI/ESD)

Difficult sputtering

However, IPS LCD technology is prone to static charges and ESD (electrostatic discharge), and shielding layers are needed to protect the displays. Typically, a thin sputtered layer of ITO (indium tin oxide) on the color filter glass would suffice. However, ITO sputtering becomes increasingly difficult as display glasses are highly slimmed and substrate sizes grow larger. Wet coating such as slot-die or spray-coating do clearly outplay sputtering and provide the additional benefits of being faster throughput, less downtime and higher material yield.

Advanced formulations

Heraeus offers advanced conductive polymer formulations, Clevios™ F ELO, optimized for optical quality coatings on display glass. The product can be applied by an economical wet-coating process on the displays as a shielding layer. Excellent optical properties, a well adjustable and uniform sheet resistance, and high hardness and durability are some of the key features.

Controlling light reflection

When it comes to light reflection losses, Clevios™ clearly outperforms ITO due to its lower refractive index of approximately 1.5, matching well with glass. Compared to ITO coatings, light reflection is reduced by up to 50%. This can help improve display contrast such as in automotive interior applications where light reflection is a challenge.