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Lithium tetraborate(Li2B4O7 : LBO)crystal is a superior substrate material for surface acoustic wave and bulk acoustic wave devices due to its fairly high electromechanical coupling factor(k2 =1%)and zero temperature coefficient of frequency in(110)plane.In the past decades,we are engaged in the developed of large size LBO piezocrystals and industrial growth of φ3~4" LBO crystals has been realized by the modified vertical Bridgman method.The technique shows several advantages..(1)the crystal shape depends on the shape of the crucible,which means high utility of as-grown crystals;(2)a small temperature gradient in the solid-liquid interface and in-situ annealing process considerably reduce the thermal stress in crystals;(3)5~8 LBO boules can be grown in the furnace at the same time,which means low cost.