As such the surface roughness of the first substrate 110A at the region of the microstructures MS1 may be greater than 1nm. The 底層 116A may have a thickness TU1 at the portion in contact with and may be covered by the 取向層 118A. In some embodiments, the thickness TP1 may be similar to or identical to the thickness TU1 and the thickness TC1 may be smaller than the thickness TU1, but not limited thereto. The concaves CV1 may not be covered by the material of the 取向層 118A.