[nanoPost] Thin films for next-generation displays

Company USA

Two key technologies

1. engineered substrate that provides a flexible surface on which to build a display

2. thin film coating that protects a display from harmful air and moisture.

Because it prevents moisture vapor or air from passing through, glass—durable but rigid—has been the substrate used in both traditional liquid crystal displays (LCDs), such as cell phones and digital watches, and next- generation displays such as organic light-emitting diodes (OLEDs), which offer wider viewing angles, quicker response times and more ruggedness.

One challenge to manufacturing thin, flexible, and lightweight OLEDs was finding a way to make a flexible surface, such as plastic, also impermeable to air and moisture vapor, which quickly destroy an OLED display. The coating provides this protection. It also enables the manufacture of thinner displays with fewer potential failures at seams and joints by eliminating the bulky packaging required when using a glass substrate.

The coating is made of extremely thin layers of transparent ceramic barrier material deposited with alternating thin polymer (plastic) layers. The layering is repeated until the desired resistance to water vapor and oxygen permeability is achieved. The nanoscale inorganic layers (of less than 50 nanometers) sandwiched between the polymer layers (of less than one micron) produce composite structures that are flexible enough to be rolled yet still prevent air and moisture vapor from passing through. The  coating is typically less than two microns thick. A human hair, on average, is 100 microns thick.

The flexible glass engineered substrate is a transparent, flexible plastic sheet that blocks air and moisture but allows light to be transmitted, making it extremely useful in manufacturing sensitive organic electronic devices. Vacuum deposition techniques are used to deposit thin-film layers of nanoscale organic and inorganic materials in multi-layer stacks directly onto a substrate such as polyester film. Each stack is typically less than two microns thick. Display manufacturers can use the product as the substrate on which to build either OLED or plastic LCD displays. After the device is fabricated on the barrier substrate it can be hermetically sealed using encapsulation or another sheet of Flexible Glass barrier material.