| abstract |
The complete vertical inversion of a combination of the resin layer 2 and resin layer 3 in (a) is (b). Accordingly, (a) and (b) have the same optical characteristics. Between the resin layer 2 and resin layer 3, the resin layer that is sandwiched between the substrate 1 and the uppermost resin layer (i.e., the resin layer 2 in (a) and the resin layer 3 in (b)) does not have its surface directly contacting the outside air, but the uppermost resin layer (i.e., the resin layer 3 in (a) and the resin layer 2 in (b)) has its surface contacting the outside air. Accordingly, after comparing the resin in the resin layer 2 and the resin in the resin layer 3 in terms of environmental durability, if the environmental durability of the resin in the resin layer 2 is superior to the environmental durability of the resin in the resin layer 3, the construction shown in (b) may be adopted, and if the environmental durability of the resin in the resin layer 3 is superior to the environmental durability of the resin in the resin layer 2, then the construction shown in (a) may be adopted. |