Method for forming fine concavo-convex patterns, method for producing optical diffraction structure, and method for copying optical diffraction structure
A method for forming fine concavo-convex patterns by using a relief formation material 3 having a relief formation layer 2 composed of a resin having thermoplasticity and a relief pattern sheet 6 having on a surface thereof fine concavo-convex patterns 5 , wherein a photothermal conversion layer 7 is formed in the relief formation material 3 or the relief pattern sheet 6 ; the photothermal conversion layer 7 is irradiated with light 8 to make the photothermal conversion layer 7 generate heat in the state that the relief formation layer 2 is brought into contact with the fine concavo-convex patterns 5 ; and the fine concavo-convex patterns 5 are formed on the relief formation layer 2.
1. A method for forming fine concavo-convex patterns, the method comprising:
providing a relief formation material comprising a substrate for the relief formation material composed of plastic film, a photothermal conversion layer 0.1 to 5 μm thick on the substrate for the relief formation material, and a relief formation layer composed of an ionizing radiation-curable resin having thermoplasticity on the photothermal conversion layer;
forming a relief pattern sheet by coating a second ionizing radiation-curable resin composition onto a substrate, contacting the second ionizing radiation-curable resin with a diffraction lattice pattern resin master-hologram having fine concavo-convex patterns, partially curing the ionizing radiation-curable resin composition by temporarily exposing the substrate and diffraction lattice pattern resin master-hologram laminate to ionizing radiation thereby imparting the fine concavo-convex patterns from the diffraction lattice pattern resin master-hologram to the second ionizing radiation-curable resin, separating the diffraction lattice pattern resin master-hologram from the second ionizing radiation-curable resin, exposing the fine concavo-convex patterns of the substrate to further ionizing radiation to completely cure the fine concavo-convex patterns in the second ionizing radiation-curable resin;
contacting the relief formation material and the relief pattern sheet with each other in such a manner that the relief formation layer is brought into contact with the fine concavo-convex patterns of the substrate, the fine concavo-convex patterns of the master hologram corresponding to the fine concavo-convex patterns formed on the relief formation layer;
irradiating the photothermal conversion layer with an energy beam from the relief pattern sheet side to make the photothermal conversion layer generate heat; and
separating the relief pattern sheet and the relief formation layer and exposing the relief formation layer to curing ionizing radiation.
2. The method for forming fine concavo-convex patterns according to claim 1 , further comprising providing the relief formation layer as an ionizing radiation-curable resin having thermoplasticity.
3. The method for forming fine concavo-convex patterns according to claim 1 , wherein during the contacting step, the relief formation material and the relief pattern sheet are attached to each other by vacuum adsorption.