For some transparent raw materials such as glass and plastics, internal stress is inevitable, and its existence will not only affect the stability of the surface of raw materials, resulting in deformation of raw materials, but also affect the quality of finished products. For glass, uneven stress distribution may also cause accidents.
Therefore, it is also very important to control the internal stress of glass, plastics, etc. Within a certain range. Nowadays, the instrument commonly used to measure the internal stress of products is the Polariscope such as glass polariscope.
The operating principle of the polarized stress meter is based on the stress birefringence detection, that is, the glass is an isotropic body with the same refractive index in all directions. If there is stress in the glass, the isotropic properties will be destroyed, resulting in the change of refractive index, the refractive index of the two principal stress directions is no longer the same, and the birefringence phenomenon will occur.
The birefringence causes the material to produce optical phase retardation. As long as the phase retardation value can be measured, the internal electric force of the material can be known. Moreover, the value given by most polarization stress meters is the phase retardation value.
It is suitable for pharmaceutical enterprises, glass products factories, molding products factories and laboratories to measure the stress value of optical, glass products and other optical data.
