Roll-to-roll-imprinting
The present invention relates to roll-to-roll surface patterning by imprint method. A film of liquid phase resist is coated on a running web and subsequently brought into contact with a rolling replication tool with patterned features on its outer surface. In a simultaneous step, resist is 5 cured typically by heat or UV-light and patterned features on the rolling replication tool are replicated into the resist film during the contact with the replication tool. A major deficiency of conventional roll-to-roll imprinting is the generation of defects in the patterns due to trapped air. To overcome this limitation, the present invention describes a method and 10 apparatus to perform roll-to-roll imprinting under reduced-pressure or vacuum conditions.
1 . A roll-to-roll nanostructure manufacturing method comprising steps of:
unwinding a substrate web;
optionally pre-treating the substrate web;
preparing a resist by mixing at least two component substances, or obtaining and optionally stirring a single-component resist;
coating the substrate web with the resist to form a resist film;
patterning the resist film in a continuous process by applying a pressure on the resist film by pressing the resist film between the substrate web and a mold placed at or formed on the outer surface of a rolling replication tool, thereby the mold defining a plurality of nanostructures in the resist;
curing the patterned resist film comprising the mold-patterned nanostructures, wherein the curing at least partially occurs prior to detaching the patterned resist from the mold; and
rewinding the substrate web with the cured nanostructures,
enclosing apparatus for performing the steps in a reduced-pressure chamber,
reducing air pressure in the reduced-pressure chamber, so that air pressure within the reduced-pressure chamber is between 0 atm and 0.5 atm, and
performing the steps of the roll-to-roll nanostructure manufacturing method by said apparatus enclosed in the reduced-pressure chamber after said reducing of the air pressure.
2 . The roll-to-roll nanostructure manufacturing method according to claim 1 , wherein the method further comprises at least one of:
unwinding a protective liner from the unwound substrate web before performing the optional pre-treatment the substrate web by the pre-treatment unit and/or before coating the substrate web with the resist film, and
feeding a protective liner on top of the cured nanostructure on the substrate web before rewinding the substrate web with the cured nanostructures,
wherein
apparatus for performing said unwinding the protective liner and/or said feeding the protective liner is enclosed within the reduced-pressure chamber, and
said steps of unwinding the protective liner and/or said feeding the protective liner are performed within the reduced-pressure chamber after said reducing air pressure.
3 . The roll-to-roll nanostructure manufacturing method according to claim 1 , wherein the method further comprises at least one of:
adjusting an infeed angle of the substrate web coated with the resist film;
adjusting a pressure applied to the resist when it is pressed between the mold and the substrate web;
adjusting a curing temperature used for curing the resist;
adjusting an intensity of radiation used for curing the resist; and
adjusting a demolding angle of the substrate web with the at least partially cured resist.
4 . The roll-to-roll nanostructure manufacturing method according to claim 1 , further comprising:
obtaining each of the substances of the resist to be mixed from a respective storage container, wherein said respective storage container is within the reduced-pressure chamber, or said respective storage container is external to the reduced-pressure chamber, wherein internal pressure within the storage container is between 0 atm and 0.5 atm.
5 . The roll-to-roll nanostructure manufacturing method according to claim 1 , wherein the resist is an uncured monomer or pre-polymer mixture prepared by mixing said at least two component substances, or the resist is single-component substance.
6 . The roll-to-roll nanostructure manufacturing method according to claim 1 , wherein the method comprises:
reducing air pressure in the reduced-pressure chamber, so that air pressure within the reduced-pressure chamber is between 0.1 atm and 0.5 atm.
7 . The roll-to-roll nanostructure manufacturing method according to claim 4 , wherein internal pressure within the respective storage container is between 0.1 atm and 0.5 atm.
8 . The roll-to-roll nanostructure manufacturing method according to claim 4 , wherein internal pressure within the respective storage container is equal to the air pressure within the reduced pressure chamber during operation of the roll-to-toll imprinting apparatus.