Patent ID: 7399360
Filing Date: 2008-07-15
Classification: C30B,Y10T

Abstract:
1. A crucible for growth of a single crystal along the crystal plane of a seed by melting and cooling an optical part material, comprising a starting material carrying section in which the starting material of said optical part material is loaded and a seed carrying section in which said seed is loaded characterized in that a tapered cone surface is formed between the starting material carrying section and the seed carrying section in which said seed is loaded, the wall surface of said starting material carrying section is smoothly connected to the cone surface via a concave curved surface having a curvature radius of at least 1/10 of an inner diameter within the wall surface of the starting material carrying section, and said cone surface is smoothly connected to the wall surface of the seed carrying section via a convex curved surface having a curvature radius of at least 1/10 of an inner diameter within the wall surface of the starting material carrying section, and further characterized in that the surface roughness of the inner surface of the crucible as measured by the maximum height method is no greater than R