| 摘要 |
PURPOSE:To easily and surely produce fine spherical surface shapes by combining a photographic technique and an etching technique to form many fine hemispherical recesses of high accuracy on the surface of a mold material. CONSTITUTION:A halftone pattern film 4 is superposed on a film 5 for continuous tone in tight contact therewith and is exposed; thereafter, a transparent film 6 and a diffusion sheet 7 are held between the film 5 for continuous tone and the halftone pattern film 4 in an undeveloped state. These films are superposed on each other in tight contact therewith and are exposed. This film 5 for continuous tone is developed to form an original plate 8 for etching. This original plate 8 is brought into tight contact with a continuous tone film 12 of a high contrast and is exposed; thereafter, the continuous tone film 12 is developed to obtain a positive original plate 13. This positive original plate 13 is brought into complete tight contact with carbon tissue 15 and is exposed. The exposed carbon tissue 15a is stuck to the mold material 16 (copper material) and is etched, by which a metallic mold 1 is produced. The metallic mold 1 having a mold surface 3 consisting of the many fine semispherical recesses of high accuracy is easily and surely obtd. in this way. |
