MANUFACTURE OF SYNTHETIC RESIN CASTING HAVING WEDGY SECTION

PURPOSE:To enable manufacturing of a wedgy light guide plate which has high productivity, costs small and is superior in optical properties, by a method wherein the lower ends each of two templates are confronted with each other in a V-shaped state, both ends of an obtained wedgy space is sealed with a specific, flexible and platelike material and after casting of a resin material to be polymerized into the space, the same is left under a polymerized atmosphere while keeping the same under an upright state. CONSTITUTION:The lower ends each of two templates 2, 2' are confronted with each other in a V-shaped state and a confronting part is connected rockably with each other by making use of an adhesive tape 3. Along with the same, both ends of an obtained wedgy space is sealed with a flexible platelike material which is rich in solvent resistance against a resin monomer to be polymerized, an opening surface of the top space is sealed appropriately after casting of the resin material to be polymerized into the space and the same is left under a polymerized atmosphere while keeping the same under an upright state. Then the same is bulk-polymerized by adding polymerization accelerating means. With this construction, various bulky light guide plate which has high productivity and is superior in optical properties can be massproduced at a low cost.