" deformation temperature and thermal decomposition temperature) of the binder resin in the light-heat exchange layer is preferably higher than that of materials used in other layers formed on the light-heat exchange layer. [0048] Examples of such a binder include homopolymers and copolymers of acrylic monomers such as acrylic acid and the like (e.g. poly(methyl methacrylate)); cellulose polymers s" . . . .