| 摘要 |
PURPOSE:To prevent the breakage of a crucible due to shrinkage at the time of cessation of heating and to improve durability by constituting the shape of the internal surface of a crucible of a combination of a spherical base and a conical side face widening upward. CONSTITUTION:The internal surface 5, to be in contact with a molten substance 3, of a crucible 1 made of graphite used as an evaporation source for vacuum vapor deposition is formed of a combination of a spherical base 6 and a conical side face 7 widening toward the upper part of the crucible 1. It is preferable that the base 6 has a nearly semi-spherical spherical plane whose diameter becomes maximum in the upper part and also the side face 7 has a conical plane widening upward at an angle of about 5-45 deg. with respect to the vertical axis of the crucible 1. Even if the crucible 1 is shrinked earlier than the molten substance 3 when the heating of the crucible 1 and the evaporation of the molten substance 3 are stopped, the breakage of the crucible 1 due to contraction can be avoided because the solidified molten substance 3 in the crucible 1 is raised upward by its shrinkage force. Accordingly, heating and evaporation can be repeatedly carried out while obviating the necessity of taking the molten substance 3 out of the crucible 1. |
