INJECTION-COMPRESSION MOLDED OPTICAL RESIN SHEET, APPARATUS AND METHOD FOR INJECTION-COMPRESSION MOLDING

PROBLEM TO BE SOLVED: To suppress a decrease of durability caused by a wear or a deformation with an excellent machining accuracy without internal strain of a resin molding by forming an optical structure on a surface by injection-compression molding, stopping a flow of an injection-compression resin of a molten state, finally clamping a mold and making the strain uniform. SOLUTION: A hydraulic cylinder 12 is driven to move a shut-off member 9 so as to connect a channel 9A to an introducing unit 6B and a cavity 8. Then, a movable mold 6 is brought into close contact with a fixed mold to form the cavity 8. Molten resin is supplied to a sprue 5, and charged in the cavity 8 at a high pressure through the channel 9A. At this time, the mold 6 starts separating from the fixed mold by means of a pressure of the charged molten resin. Here, the cylinder 12 is driven to move the member 9 to shut OFF the unit 6B from the cavity 8. A mold clamping force of the mold 6 is maximized, the mold 6 is brought into close contact with the fixed mold, a compression force is uniformly applied to the resin of the cavity 8, and hence a small pattern 6A is transferred.