Method and device for orientated growth of fluoride crystals by bridgman method

The invention provides a device and method for orientated growth of fluoride crystals by a bridgman method. The device and the method is characterized by that when the fluoride crystals in a specific direction grow under a vacuum condition by the bridgman method, seed crystals in the specific direction are placed in a hole of a neck of a crucible, and in order to ensure that the seed crystals are melted partially in an early growth stage of the crystals, lower portions of the seed crystals are protected against being melted by a method of mounting an umbrella-shaped reflecting screen on the outer side of the neck of the crucible; and the temperature of the seed crystals is monitored in real time by a non-contact type optical pyrometer so as to ensure the upper portions of the seed crystals to be melted fully but the lower portions of the seed crystals not to be melted, and single crystals can grow in an orientated mode under the condition. According to the umbrella-shaped reflecting screen and the optical pyrometer provided by the invention, the temperature is measured in the initial stage of growth of the crystals, the seed crystals can be exactly melted effectively by one-third to half in the initial stage of growth of fluoride single crystals in the specific direction, and in a regrowing process, a sensor of a temperature control portion is switched into a thermocouple so as to control temperature until growth of the crystals is finished.