Synthetic sapphire is a single crystal of aluminum oxide, a transparent colorless variety of sapphire. Sapphire is one of the hardest minerals, optically transparent, has a high melting point, and is extremely resistant to damage, including in aggressive environments. It has high thermal conductivity at low temperatures and record-breaking high resistivity. Sapphire is synthesized on an industrial scale throughout the world. Currently, the main use of synthetic sapphire is the production of substrates for LEDs and integrated silicon microcircuits (SoS), used to create windows for airplanes and armored vehicles, as well as to protect the dial in expensive watches. Recently, Apple has found the use of synthetic sapphire as very durable glasses in its popular innovative products (iPhone, iPad, iWatch, etc.). For the cultivation of high-purity sapphire single crystals of large size, suitable for the production of plates for the manufacture of substrates with different orientations and other products with high optical properties, the Kyropoulos method is usually used. Raw material for it is powdered or crystalline alumina. This relatively inexpensive method is based on the growth of crystals from the melt.
The task was to modernize the existing equipment of the type “XXX” for growing sapphire single crystals. To do this, it was necessary to develop and integrate into the existing growth machine a modern automated system with a human-machine interface for controlling crystal synthesis modes (based on equipment and NI LabVIEW of National Instruments Corporation). Moreover, it was necessary to equip the new system with an innovative solution that allows the seeding of the crystal in a fully automatic mode without an operator. For this, the automated system was supplemented with the function of technical vision.
The main results were obtained with the implementation of the project:
In the developed automated control system, the following main functions were transferred to the new platform: