High-speed replication of light-extraction structure with thermal roller nanoimprinting

[Display omitted] •We demonstrated the high-speed replication of a light-extraction structure by thermal roller nanoimprinting.•The relationships between the replicated structure, the feeding speed and the heating temperature were investigated.•A microlens array pattern was replicated onto a polymethyl methacrylate film at a speed of 2500mm2/s.•The replicated pattern height was 11μm, compared with the mold depth of 15μm.•The light-extraction efficiency of the patterned film was 1.37 times that of a flat film. We demonstrated the high-speed replication of the light-extraction structure of an organic light-emitting diode (OLED) by thermal roller nanoimprinting (TRN). The mold used consists of a Ni substrate with a microlens array (MLA) pattern as the light-extraction structure. The roller mold is heated then pressed on a polymethyl methacrylate (PMMA) film. The heated surface of the pressed PMMA has a low viscosity and fills the mold pattern, thus replicating the nanostructure. In this method, replication can be achieved with a short cycle time compared with conventional thermal nanoimprinting. The effect of the heating time in TRN on the replicated pattern height is investigated by heat conduction calculation and experimentally. Furthermore, the relationship between the light-extraction efficiency and the replicated pattern height is investigated by the ray-tracing method and optical measurement. We successfully demonstrated replication at a speed of 2500mm2/s using a mold with an MLA pattern having a 15μm height. The replicated pattern height was 11μm and the light-extraction efficiency of the patterned film was 1.37 times that of a flat film.