| 摘要 |
The invention provides a thin optical lenses forming apparatuses with little distortion and excellent stability of surface accuracy. In the manufacturing method of the optical lens forming apparatus, injection moldings are carried out for the annular ethylene series resins through a die combined through an opening of a sprue. The die corresponds to a cavity and the sprue of the die, thereby an optical lenses forming apparatus with a flange combined with the lens by a recess and diameters less than 10mm is produced. In addition, the flange is provided with a thickness less than 0.5mm. The recess, thinner than the flange, is provided with a thickness less than 0.4mm. The invention is characterized in that injection moldings are carried out for the annular ethylene series resins through the die. The sprue thickness t1 and the flange thickness t2 at the opening of the sprue along the height direction of the die cavity meet a formula (1) as t2*0.1<=t1<=t2. Moreover, the sprue gets narrowed at the side facing the height direction of the die cavity. An inclination angle Beta meets a formula (2) as the Beta is not less than 20 degrees but not more than 60 degrees. |
