The surface stress meter is an instrument used to detect the value and distribution of stress in transparent products. It is not only widely used in optical glass, optical instruments, glass products, plastic products and other industries, but also occupies an important position in the inspection of safety and explosion-proof indicators of building materials, lamps, pharmaceuticals, beverages, and handicrafts. It is used in the production of crystal jewelry, geology and minerals, and materials. There are also many applications in the field of science. At the same time, the surface stress meter is also an ideal teaching experiment equipment for universities and colleges.
The measuring principle of the surface stress meter is to use the optical waveguide effect of the ion exchange layer on the glass surface to measure. The divergent light emitted from the light source passes through the slit and is condensed by the high refractive index cylindrical prism to become parallel light. By adjusting the position of the light source, a beam of parallel light is incident on the interface between the glass and the prism at a critical angle.
Due to the stress on the glass surface, the light is decomposed into vector light perpendicular to the two vibrating surfaces. The two beams of light have different propagation velocities in the ion exchange layer of glass, so they are refracted to the prism at different total reflection angles. The light emitted from the prism is reflected by the mirror into the interference filter, focused by the telescope system, and then imaged on the reticle after passing through the analysis mirror to form a bright and dark step image. Through the analysis software, the height of the step and the number of step lines can be accurately measured to calculate the surface stress intensity and the depth of the stress layer. Due to uneven cooling or other reasons such as mechanical action, internal stress will be generated in transparent objects, resulting in birefringence. Crystal material itself has the optical characteristics of birefringence.
The Glass Surface Stress Meter (ASM-200FAP)measures surface compressive stress of chemically tempered glass and the depth of stress layer according to photoelastic technology by letting light spread along the glass surface. This equipment is equipped with a PC, which can reduce measurement errors caused by operators . Moreover, it is more convenient for the management of measuring data. Thickness Gauge is optional to improve the measurement efficiency. It has been widely used in the quality control for phone glass panel , LCD panel and other chemically tempered glass panel.
