METHOD OF GROWING MONOCRYSTALLINE SAPPHIRE HEMISPHERICAL BLANKS Russian patent published in 1997 - IPC

FIELD: crystal growing. SUBSTANCE: invention relates to technique of growing crystals from melt with variable cross-section shape. Proposed method is distinguished with that seeding is conducted onto seeding plate along all the perimeter of tubular shaper to form a hollow closed space. End surface of shaper is made with central recess in the form of spherical segment. Stretching out is effected from the column of melt. When hollow profile is transformed into monolithic one, blank is stretched to a length equal to height of spherical segment, whereupon crystal is sharply detached from the shaper. It is additionally possible to obtain several hemispherical blanks during one growing cycle. To do this, a hemispherical blank, once detached, is used for repeated seeding over all shaper perimeter, while another blank is stretched out. Number of seedings depends on required number of blanks. This additional performance may be achieved with by still moor efficient way: when blank is stretched out to required length, shaper hollow is connected to atmosphere through side opening which is closed when following blank begins growing. EFFECT: improved procedure and increased productivity. 3 cl, 7 dwg