In many applications conductive coatings are used to form electrical circuits. Eikos is able to formulate stable CNT inks for a variety of patterning techniques.
Invisicon coating technology enables use of both additive and subtractive coating methods.
The direct formation of conductive coating, through additive patterning, eliminates the multistep process typically needed during the subtractive patterning process. For example ITO is typically uniformly coated over a substrate, then photo lithographic processing steps are used to remove excess coating and form a pattern. This approach requires many steps, use of wet chemical etching, washing, and extensive handling all of which greatly increases cost and environmental impact.
Invisicon® can be directly coated using any common additive patterning techniques. For example gravure, imprinting, masking, and inkjet.
Invisicon coatings can be patterned additively and subtractively. Vacuum deposited transparent conductors can only be patterned substractively, limiting their utility and complicating their manufacturing. Because of the two-step deposition process, nanotubes can be patterned, while the binder is uniform. This possibility allows for independently designing the optical and electronic properties of a device. Eikos has demonstrated patterning several ways:
Additive Patterning is achieved by techniques like gravure and inkjet printing. Additive patterning is advantageous because it reduces ink waste and eliminates manufacturing steps. Additive patterning can be applied to prototyping or large-scale roll-to-roll printing.
Substrate Patterning is a convenient way to pattern nanotube and binder coatings deposited after substrate treatment. By locally depositing a hydrophobic layer onto the substrate, Invisicon inks will selectively remain on hydrophilic areas. This method is compatible with spray and slot-die coated Invisicon.
Subtractive Patterning is completely compatible with Invisicon. Eikos has demonstrated photolithography as a simple means to create patterned nanotube film. Removal of unwanted Invisicon coating from the substrate is complete, resulting in fine, conductive wires. Additionally, Eikos has demonstrated that excimer laser patterning is an effective subtractive method to pattern Invisicon coatings.