Abstract: An apparatus for producing a light transmitting article of synthetic resin in which a monomer Ma is incompletely polymerized to form a network polymer Pa having a refractive index Na, thereby forming a self supporting body material, and subsequently a monomer Mb, which forms a polymer Pb having a refractive index Nb different from the refractive index Na, is diffused into the body material and simultaneously polymerized. The apparatus includes a mold in which the body material is formed, a diffusion chamber in which the monomer Mb is diffused into the body material, and a heat-treating tube for heating the body material so that the distribution of the monomer Mb is fixed in the body material. According to the invention, a light transmitting article of synthetic resin is produced continuously in good quality.

Abstract: A method of producing a light transmitting article of synthetic resin by polymerizing incompletely a monomer Ma which forms a network polymer Pa having a refractive index Na, thereby forming a self-supporting body material, and subsequently diffusing a monomer Mb, which forms a polymer Pb having a refractive index Nb different from the refractive index Na, into said body material and simultaneously polymerizing said monomer Mb, wherein said method comprises steps of drawing out continuously a body material from a molding means in which said body material has been formed and is ready for the diffusion of the monomer Mb, and passing said body material through a diffusion means and a heating means one after the other, diffusing the monomer Mb into said body material by the aid of said diffusion means and then heating said body material by the aid of said heating means so that the distribution of said monomer Mb is fixed in said body material.