| 摘要 |
PURPOSE:To sufficiently observe even a large-bore single crystal by forming a concave surface on the tip of a quartz rod in the titled device provided with the quartz rod for observing the growth condition of the inside single crystal from the outside. CONSTITUTION:The growth condition of a single crystal in the device is observed by the quartz rod 4 from the outside in the device 6 for growing the single crystal of a easy-to-decompose compd. semiconductor consisting of an element having a high vapor pressure. In this case, one tip part (side surface part) 7 of a rod 4 is made concave to the outside, and the radius of curvature is made smaller than the distance between the tip part 7 and a body 8 to be observed. Since the tip part 7 is made concave in this way, the same action as a lens is provided, and the visual field is widened with the same diameter. When the angle between the normal 3 at the worked tip part and a light beam 2 passing through the quartz rod is assumed to be theta1 and the angle between the normal 3 and a light beam 1 passing through a gas to be theta2, the equation can be obtained by the Snell laws of refraction (n1 and n2 are the refractive indexes of the respective mediums). Since n1>n2 in this case, theta1<theta2, and the visual field is widened.
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