METHOD FOR PRODUCING END SURFACES WITH CURVATURE ON SAPPHIRE SINGLE CRYSTALS Russian patent published in 2021 - IPC C30B15/34 C30B29/20 C30B29/62 C30B29/66 G02B1/02 G02B3/00 

FIELD: growing single-crystal sapphire billets.

SUBSTANCE: invention relates to the field of growing single-crystal sapphire billets from a melt for the manufacture of parts from sapphire for optical applications, microscopy, measuring technology. The method for producing end surfaces with curvature on sapphire single crystals includes seeding from the surface of the shaper 1 onto a seed crystal 3, growing a crystal 4 of the required shape from the melt column 5 and a sharp separation of the crystal 4 from the shaper 1, which is made with cylindrical recesses 2 with a working surface diameter d, equal or greater than the transverse dimensions of surfaces with curvature 7, and depth H equal or greater than d, the position of grooves 2 corresponds to the position of surfaces with curvature 7 in the section of crystal 4, before the separation of the crystal 4, the grooves filled with melt 5 are located under the crystallization front 6. At the moment of separation the condition of the engagement of the meniscus of the melt 5 over the edge of the cylindrical recess 2. The former 1 is made with an opening of the supply channel with a diameter of 10 to 200 μm. Before the separation of the crystal 4, the height of the melt meniscus is increased by increasing the temperature in the crystallization zone and / or increasing the rate of crystal growth.

EFFECT: technical result consists in simplifying the technological process of obtaining end optical surfaces with curvature on single crystal sapphire, reducing the transverse dimensions of products to 0.3 mm or less, on which surfaces with curvature are obtained.

4 cl, 4 dwg