Method of Measuring Internal Stress Distribution of Sapphire Based on FPGA and Polarization Difference Algorithm

Abstract

The invention relates to a sapphire internal stress distribution measuring system based on a field programmable gate array (FPGA) and a polarization difference algorithm, and belongs to the technical fields of analysis and measuring control. The system consists of a laser light source, a light measuring elastic device and a linear array charge coupled device (CCD) detection device. According to the system provided by the invention, the stress distribution in a sapphire substrate and residual stress on a specific crystal surface are researched by combining polarization imaging and a photoelastic method, the internal stress distribution of sapphire is subjected to equal-precision measurement and calculation by using the polarization difference algorithm and the FPGA, and an advanced analysis and measuring control technology is adopted, so that the technical defects in the traditional measuring method and the existing optical measuring method are solved, and the guidance is provided for optimization of the sapphire substrate processing process.

Description

technical field [0001] The invention relates to a system for measuring sapphire internal stress distribution based on FPGA and polarization difference algorithm, which belongs to the technical field of analysis and measurement control. Background technique [0002] Today's semiconductor lighting industry has a bright future, and LED manufacturers around the world are actively expanding. Fiery investment has driven the demand for upstream materials. Sapphire is currently the most widely used and most industrialized LED chip substrate material. With the continuous expansion of downstream demand in the LED industry chain, the sapphire market is showing a rapid development trend. It is estimated that the sapphire substrate, the upstream material of LED chips, is urgently out of stock. [0003] In fact, during the production process of sapphire substrates, the internal stress distribution of substrate materials has an important influence on the properties of corresponding devic...

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Problems solved by technology

[0004] In view of the above problems, the purpose of the present invention is to provide a system for measuring the internal stress distribution of sapphire based on FPGA and polarization difference algorithm, which solves the limitation of material anisotropic stress measurement in traditional measurement methods and the existing optical measurement method. The problems that have a serious impact on the performance of materials provide guidance for the optimization of sapphire substrate processing technology. It has the characteristics of clear principle, high measurement accuracy and easy operation.

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