| 摘要 |
The invention relates to a mould and a method for the hot forming of a thermoplastic optical lens. The inventive mould consists of two dies (1, 2) which are mounted in a hollow shaft (3), so as to slide along the axis (6) thereof, and which comprise opposing forming surfaces (4, 5). The two dies (1, 2) and the shaft (3) are provided with intrinsic heat transfer means. The inventive method comprises the following steps, consisting in: placing a paraison or preform (P) of said thermoplastic material between the two dies (1, 2) and enclosing all of the latter inside the shaft (3); heating the dies (1, 2) and the shaft (3) to a forming temperature, using the intrinsic heat transfer means thereof (15, 16, 19, 20); bringing the dies (1, 2) closer together, in order to form the material by means of plastic deformation, until a pre-determined relative position is reached, said position corresponding to the desired thickness of the lens; cooling the dies (1, 2) and the shaft (3) to a stripping temperature, using the intrinsic heat transfer means thereof (15, 16, 19, 20); and extracting the finished lens (L) from the mould. |
