Abstract: A retardation film includes a plurality of unit areas in a direction parallel to a light-incident plane of the optical element, and the unit areas includes a plurality of unit areas 2 whose retardation with respect to light of a certain wavelength is different by 10 nm or more from retardation of adjacent unit areas with respect to light of the certain wavelength. The retardation film utilizes a difference in wavelength dependence between retardation r(n, ?) of each of the unit areas and synthetic retardation R(?) of a whole area including all of the unit areas. This realizes an optical element capable of easily controlling wavelength dispersion of retardation, without being constrained by a material.

Abstract: The invention aims at a curing agent, curable compositions or compositions for optical materials, capable of providing for cured artifacts having laudable heat resistance, optical transparency, and light resistance; optical materials and methods for their production; and liquid crystal displays and LED's made by using the materials. A curing agent, which comprises at least two SiH groups, is obtainable by subjecting an aliphatic organic compound (?1) and an acyclic and/or cyclic polyorganosiloxane (?1) to hydrosilylation reaction. The curing agent is also obtainable by subjecting an organic compound (?2) and a cyclic polyorganosiloxane (?2) to hydrosilylation reaction.

Abstract: The invention aims at a curing agent, curable compositions or compositions for optical materials, capable of providing for cured artifacts having laudable heat resistance, optical transparency, and light resistance; optical materials and methods for their production; and liquid crystal displays and LED's made by using the materials.