METHOD OF MEASURING LEVEL OF MELT AND ROTATIONAL SPEED THEREOF WHEN GROWING CRYSTALS Russian patent published in 2015 - IPC C30B15/26 G01B11/03 

FIELD: physics, optics.

SUBSTANCE: invention relates to growing crystals. A diverging probing laser beam is directed onto the surface of a melt at an angle to the vertical axis. The obtained narrow light band is directed along the radius of the crucible. The position of the light beam reflected from the melt is then determined using a two-dimensional photodetector and an optical system. In the absence of rotation of the melt, the reflected beam falls on the peripheral part of the optical system, and upon increase deflects towards the opposite peripheral part. The photodetection plane of the photodetector is optically mated with the plane passing through the axis of the probing beam and the light band on the surface of the melt. In the plane of the two-dimensional photodetector, an image of a fragment of the light band is formed, which is shifted in an orthogonal direction when the level of the melt changes, said level being measured based on said shift. The next fragment of the light band located closer to the periphery of the crucible is formed with increase in the rotational speed of the melt in the plane of the two-dimensional photodetector. Angular velocity of melt is determined from the value of the shift of said fragment along the light band. The invention can be used in any growth apparatus.

EFFECT: improved method.

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