Bilateral misalignment differential confocal ultra-long focal length measurement method

Abstract

The invention provides a bilateral misalignment differential confocal ultra-long focal length measurement method, and belongs to the technical field of optical precision measurement. According to thebilateral misalignment differential confocal ultra-long focal length measurement method disclosed by the invention, in a confocal measurement system, large and small virtual pinhole detection areas are set via software on an Airy disk image detected by a CCD, subtraction processing is performed on two confocal characteristic curves detected by the CCD to sharpen the confocal characteristic curves,then bilateral misalignment differential subtraction processing is performed on the confocal characteristic curves to obtain differential confocal characteristic curves with high axial sensitivity, and then zero points of the bilateral misalignment differential confocal characteristic curve and a focal point of the confocal measurement system accurately correspond to the characteristic to preformhigh-precision focusing positioning on position points of a mobile measurement plane mirror in ultra-long focal length measurement, so as to achieve the high-precision measurement of the ultra-long focal length. Compared with the existing ultra-long focal length measurement method, the bilateral misalignment differential confocal ultra-long focal length measurement method provided by the invention has the advantages of high measurement precision, high ambient interference resistance, simple structure and the like, thereby having a wide application prospect in the technical field of optical precision measurement.

Description

technical field [0001] The invention relates to a bilateral misalignment differential confocal ultra-long focal length measurement method, which belongs to the technical field of precision measurement of optical element parameters. [0002] technical background [0003] Long focal length optical components are widely used in the research fields of large optical systems such as laser nuclear fusion, space optical systems and high energy lasers. However, the high-precision measurement of the focal length of long focal length lenses has always been a major problem in the field of optical testing, and its measurement accuracy also directly affects the imaging quality and performance of large optical systems. Therefore, finding a high-precision measurement method with a long focal length has very important application value, and it is also a technical bottleneck to be solved urgently in the development and installation of major national projects such as laser nuclear fusion, space...

AI Technical Summary

Problems solved by technology

[0008] 1) The depth of focus is long and affected by the diffraction effect, it is difficult to focus accurately;

[0009] 2) The focal length is long and the measurement optical path is long, which is difficult to measure precisely due to the influence of measurement environment interference and system drift;

[0011] Aiming at the problem of ultra-long focal length and high-precision measurement, the inventor once re-innovated the principle of confocal microscopic imaging used in the field of microscopic measurement, and successfully pioneered the confocal microscopic technology in the field of microscopic imaging testing for the first time in the world. It is widely used in the field of measurement of large-scale optical components, and related papers have been published in OpticsExpress, a well-known international journal in the field of optics (Optics Express, v17, n22, 2009; Optics Express, v18, n3, 2010; Optics Express, v21, n19, 2013) At the same time, it also applied for and authorized the Chinese invention patents "Confocal combination ultra-long focal length measurement method and device" (ZL 200810226967.6), "Differential confocal combination ultra-long focal length measurement method and device" (ZL200810226966.1) and "Differential Confocal internal focusing method lens optical axis and thickness measurement method and device” (ZL 201010121848.1) and many other invention patents, but the above inventor’s papers and patents still have low sensitivity of fixed focus and resistance to environment when measuring fixed focus with ultra-long focal length Insufficient interference capability and complex fixed focus system

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