Research on Total Internal Reflection Detection Technology for Subsurface Defects of Optical Elements Based on...

During the manufacturing of precision optical elements, subsurface defects seriously affect the performance of the elements, leading to the enhancement of light fields, an increase in laser absorption and an decrease in mechanical properties. It has become a key technology to realize the high-precision quantitative automatic detection of subsurface defects of optical elements. This paper presents a method of subsurface defect detection based on spectral confocal scattering measurement, the system adopts a dispersive lens group with the working band of 480-670 nm, and combines the spectral confocal technology and total internal reflection technology to effectively suppress the interference of scattered light on the surface, and can realize high-precision nondestructive detection without fluorescent substances. The axial resolution of this method is 0.8 μm and the measuring depth range is 0.94 mm. By building a measurement system and carrying out experimental verification, the results show that this method can accurately measure the depth and location of subsurface defects and confirm its feasibility and effectiveness.