Liquid crystal optical element comprising an alignment control layer having a plurality of projections and manufacturing method thereof

A liquid crystal optical element comprising:

• a substrate;
• a first alignment control layer disposed on the substrate and comprising projections arranged at a predetermined pitch;
• a first liquid crystal layer disposed on the first alignment control layer;
• a second alignment control layer disposed on the first liquid crystal layer and comprising projections arranged at a predetermined pitch;
• and
• a second liquid crystal layer disposed on the second alignment control layer, wherein
• the first liquid crystal layer comprises liquid crystal molecules which are aligned such that major axes of the liquid crystal molecules extend along the projections, respectively, and cured in a state where alignment directions of the liquid crystal molecules are fixed,
• the first alignment control layer is formed of a crosslinkable liquid crystal polymer,
• the second liquid crystal layer comprises liquid crystal molecules which are aligned such that major axes of the liquid crystal molecules extend along the projections of the second alignment control layer, respectively, and cured in a state where alignment directions of the liquid crystal molecules are fixed, and
• the second alignment control layer is formed of a crosslinkable liquid crystal polymer.

A manufacturing method of a liquid crystal optical element, comprising:

• applying a crosslinkable liquid crystal polymer on a substrate and forming a first alignment control layer comprising projections arranged at a predetermined pitch by a thermal nanoimprint method or a photo-nanoimprint method;
• applying a liquid crystal material on the first alignment control layer, curing the liquid crystal material in a state where liquid crystal molecules included in the liquid crystal material are aligned in a predetermined direction according to alignment restriction force of the first alignment control layer, to form a first liquid crystal layer;
• applying a crosslinkable liquid crystal polymer on the first liquid crystal layer, and forming a second alignment control layer comprising projections arranged at a predetermined pitch by the thermal nanoimprint method or the photo-nanoimprint method;
• and
• applying a liquid crystal material on the second alignment control layer, curing the liquid crystal material in a state where liquid crystal molecules included in the liquid crystal material are aligned in a predetermined direction according to alignment restriction force of the second alignment control layer, to form a second liquid crystal layer.