High tomography and anti-scatter laser differential confocal tomography method and device

Abstract

The invention relates to a high-chromatography and anti-scattering laser differential confocal chromatography focusing method and device, and belongs to the technical field of optical measurement. Forthe common bottleneck problems of high precision and anti-scattering focus of the inner and outer surfaces of components in the size parameter measurement of optical component, a confocal characteristic curve for sharpening the defocusing detection optical path system by large and small virtual pinhole lateral subtraction detection in the confocal measurement system is proposed, the differentialsubtraction process of the pre-focus and post-focus sharpening confocal characteristic curves is detected by the dual optical path to realize the differential confocal bipolar fixed focus measurementof the measured surface, the linear fitting of the differential confocal fixed focus curve is performed to improve the focus position capture accuracy, and the ray tracing model compensation is used to reduce the mutual interference between the fixed focal planes, thereby achieving high-precision chromatography focusing of the inner and outer surfaces of the optical elements / components under testand the high-precision focusing of the fine grinding scattering surface, so as to solve the common bottleneck problem of high-precision chromatography focusing in optical component parameter measurement. The technology has broad application prospects.

Description

technical field [0001] The invention belongs to the technical field of optical precision measurement, and relates to a high-resolution, anti-scattering laser differential confocal tomography focusing method and device, which can be used for the measurement of various surfaces of spherical / aspherical components, especially optical elements / components It lays the foundation for high-precision measurement of component parameters such as radius of curvature, focal length, and lens group spacing. The inventive technology can be widely used in the optical measurement of component / part dimension parameters, especially the large-size and super-large-size parameters of the component / component. [0002] technical background [0003] There is a common problem in the field of optical measurement: due to the limitation of the diffraction limit, the further improvement of the focusing ability of optical measurement is restricted, which in turn restricts the improvement of the accuracy perf...

AI Technical Summary

Problems solved by technology

[0003] There is a common problem in the field of optical measurement: due to the limitation of the diffraction limit, the further improvement of the focusing ability of optical measurement is restricted, which in turn restricts the improvement of the accuracy performance of detection instruments

Interferometric fixed focus is mainly used for fixed focus aiming on the surface of components, which restricts its application in the measurement of internal interface parameters such as lens refractive index, thickness and spacing;

[0006] 2) Poor anti-surface scattering ability

Surface scattering will destroy the conditions for forming interference, which will make it difficult for interferometric focusing to adapt to measurement fields such as non-perfect polished surface optical components, metal surfaces, and ceramic surfaces, hindering the scope of application of the interferometric focusing measurement method;

[0007] 3) Interference fixed focus speed is slow

The interference focusing method based on the acquisition and analysis of full-frame interference fixed-focus images will inevitably reduce the speed and accuracy of optical focusing, and it is difficult to achieve fast fixed-focus measurement, resulting in long measurement time and large system drift, which will ultimately affect measurement accuracy;

[0008] 4) Poor ability to resist environmental interference

[0013] Aiming at the common problem of precise focusing in the measurement of large-scale optical components, the inventor once re-innovated the principle of confocal microscopic imaging used in the field of microscopic measurement. Confocal microscopy technology is pioneered in the field of measurement of large-scale optical components, and related papers have been published in Optics Express, a well-known international journal in the field of optics, etc. (Optics Express, v17, n22, 2009; Optics Express, v18, n3, 2010; Optics Express ,v21,n19,2013), and also applied for and authorized Chinese invention patents "Measurement method and device for confocal combination ultra-long focal length" (ZL 200810226967.6), "Measurement method and device for differential confocal combination ultra-long focal length" (ZL200810226966 .1) and "Differential Confocal Inner Focusing Lens Optical Axis and Thickness Measuring Method and Device" (ZL201010121848.1) and many other invention patents, but the fixed focus method used in the above inventor's papers and patents is not figure 2 The shown long diffraction focal depth, ultra-large radius of curvature and ultra-long focal length still have problems such as low sensitivity of fixed focus and insufficient ability to resist environmental interference.

Images