| 摘要 |
PURPOSE:To surely obtain high accuracy and reproducibility of the optical axis and thickness of optical surfaces, which are transferred to a workpiece by a method wherein a conical surface is formed at the outer peripheral surface in the neighborhood of the optical surface of a punch and the inner wall part of a die, which is the holding member of the punch, is made into a conical shape, which engages with the conical surface formed on the punch. CONSTITUTION:A workpiece 31 is pinched between an upper and a lower dies 29 and 30 and between an upper and a lower punches 27 and 28 and vibrated and pressurized in the directions indicated with the thin arrows by means of an upper and a lower molding actuators 33 and 34. At this time, the workpiece 31 is softened by the heat developed by the shearing action due to vibration so as to be transferred optical surface shapes formed on the upper and the lower punches 27 and 28. In this case, since the conical surfaces 27a and 29a of the upper punch 27 and of the upper die 29 engage with each other, optical surfaces formed by the punches 27 and 28 and vertically and horizontally positioned to the predetermined positions and formed by vibrational heat, resulting in forming both the position of the optical axis and the dimension of the thickness of the optical surfaces of the workpiece 31 with good reproducibility. By shifting the upper and the lower punches 27 and 28 in the direction indicated with the thick arrows, only a portion to which the optical surfaces are transferred is blanked out of the workpiece 31. |
