Stress measurement apparatus of tempered glass, method of measuring stress of tempered glass, method of manufacturing tempered glass, tempered glass

摘要

The stress measuring device comprises a polarization phase difference variable member which changes the polarization phase difference of the laser light by one wavelength or more with respect to the wavelength of the laser light and a scattered light emitted when the laser light whose polarization phase difference is variable enters into the tempered glass, An image pickup element which picks up a plurality of images at intervals and acquires a plurality of images; and a controller which measures the periodic luminance change of the scattered light by using the plurality of images, calculates a phase change of the luminance change, And calculating the stress distribution in the depth direction from the surface of the tempered glass.