A method for preparing a multilayer of nanocrystals. The collar defines a shaft slot, into which the shaft may be inserted. The other Fresnel lens sheet comprises a Fresnel lens on one surface thereof, and a fly-eye lens or prisms as a regular concavities and convexities configuration for suppressing regular reflection on the surface thereof on a side opposite to the side having the Fresnel lens formed thereon. The first and second bores meet to form the fluid passageway.