| 摘要 |
PURPOSE:To vapor-deposit an interference thin film in uniform thickness and to improve the antireflection effect by rotating a material to be vapor-deposited whose vapor-depositing surface is a convex curved surface on its axis and vapor-depositing the interference thin film on the surface to be vapor-deposited from a specified angle. CONSTITUTION:The angle between a line 3 connecting the central point O of the spherical surface of an infrared lens 1 and one point on the outermost periphery of the convex spherical surface and the rotation axis 2 of the infrared lens 2 is regulated to alpha. When the angle between a vaporization source 4 and the rotation axis 2 is expressed as beta, the vaporization source 4 is arranged at a position where the angle betais regulated to >=1/2 the angle alpha. By this constitution, the infrared lens 1 is rotated on the rotation axis 2 and an interference thin film is vapor-deposited on the convex spherical surface of the infrared lens 2 from the vaporization source 4. The vapor deposition time is the shortest at the outer peripheral part P nearest to the vapor deposition source 4, the vapor deposition time is progressively prolonged as the distance from the vapor deposition source 4 increases and the vapor deposition velocity can be balanced. Consequently, an interference thin film can be vapor-deposited in uniform thickness over the whole convex spherical surface. |
