High precision combined optical grating device for optical 3D measurement

Abstract

The high precision combined grating device for 3D optical measurement includes 13 grating patterns etched on quartz glass via electronic beam scanning process, including 1 projector calibrating grating, 1 all-white grating, 8 Gray code gratings and 4 phase shift gratings, with the first phase shift grating being the last Gray code grating. All the gratings are in the same size, and have parallel stripes arranged orderly on the quartz glass and in the shift direction of the projecting mechanism to ensure the alignment precision. The present invention can meet the requirement of 3D optical measurement based on the Gray code method and 3D optical measurement based on phase shift method simultaneously, ensues the measurement precision and stability and has practical engineering application value.

Description

Technical field: [0001] The invention relates to a grating device, in particular to a high-precision combined grating device for optical three-dimensional measurement, comprising a projector calibration grating, a Gray code grating and a phase-shift grating made based on an electron beam scanning lithography method, belonging to mechanical engineering and optics measurement technology. Background technique: [0002] With the increasingly fierce competition in the global market, reverse engineering, as an important technology for rapid product development and product innovation design, has been widely valued and widely used in the industry. The three-dimensional measurement of objects is the first step in reverse engineering, and the accuracy of the measurement results directly affects the quality of the reverse, which plays a very important role. Optical 3D measurement is widely used at present and has become an important way of 3D measurement. In an optical three-dimensio...

AI Technical Summary

Problems solved by technology

LCD projectors project digital rasters through programming methods, which have good alignment, but cannot project stripes with continuous light intensity distribution, low contrast (about 1:20), low maximum light intensity, and small depth of field

In the prior art, G.Wiora mentioned in the High resolution measurement of phase-shift amplitude and numeric object phase calculation article published in the Proceedings of SPIE-The International Society for Optical Engineering volume 4117 in 2000 that the slide projection consists of several slide gratings Composition, can obtain more than 1:100 contrast ratio and very high light intensity, due to the small size of the slide grating, can achieve a large depth of field; its disadvantage is that the precise arrangement of the slides cannot be guaranteed, and the switching between slides is done through linear Or rotating precision displacement mechanism, the requirements for displacement accuracy are very high, so the precise alignment of the grating cannot be effectively guaranteed

Images