A method and
system referred to as PALM (Patterning by
Adhesive of Large Relief Three-Dimensional Microstructures) with large reliefs exceeding 1 μm and being as large as 100 μm. The microstructures can be either deterministic (such as microprisms), or random (such as diffusers), the first obtained by
copying an original supermaster, and latter obtained by
copying a
laser speckle pattern. The master process entails
copying a supermaster into the form of the
microstructure constituting a pattern on the patterning cylinder (called a drum), to be then continuously multiplied in the PALM
system, in a continuous roll-to-roll web process. The latter method, together with the related
system, is the subject of this invention. The rolls continuously repeat the master pattern, copying by
adhesive with large
viscosity on acrylic (
hybrid) as well as by a monolithic process. The monolithic process can be accomplished using
temperature and pressure, or by UV-cured
polymerization. Therefore, the invention comprises three alternative processes: one,
hybrid (
adhesive on acrylic), and two monolithic ones. In the PALM (
hybrid) process, an
epoxy is wet-coated on film substrates such as
polycarbonate (PC),
polyester (PET), (PE), or other flexible material. The
adhesive, in liquid form, is applied to the substrate by a self-metered
coating sub-process. In the present invention, the adhesive is used for forming the
microstructure pattern. The
microstructure pattern is replicated from a master roll or image drum onto a
coating roll.