| 摘要 |
PURPOSE:To equalize the contraction coefficient of an array direction in time of injection molding and prevent the generation of a weldline, by providing both edge parts along the lenses arranging direction of a sheet like lens array with the concave parts in a certain distance. CONSTITUTION:Concave parts 5 are provided to both edge parts 2a, 2b along the lenses arranging direction of a sheet like lens array 2 in a constant distance. The concave part 5 has at least the depth of the same degree as the height of the curved surface of each lens 1 and is provided to both the surface 2c and the back 2d of the sheet like lens array. By providing a mold 6 with the convex parts corresponding to the concave parts 5 the skin layers 7a of a molten resin 7 contacting to the mold 6 approaches each other at a concave position and the molten resin 7 is broken in its flow direction, i.e., an a array direction, then a sort of a gate seal effect is caused here. Therefore, the contraction coefficient is maintained constant in the array direction. |
