Ultra-resolution dual shaft differential confocal measurement method and device

Abstract

The invention belongs to the technical field of optical precise measurement and relates to a super-resolution double-shaft differential confocal measuring method and a super-resolution double-shaft differential confocal measuring device. In the method and the device, pupil filtering technology is fused in a double-shaft confocal measuring structure, and a differential treatment method is used for receiving a measured light beam and carrying out treatment, thereby achieving the aims of improving resolution, expanding working distance, improving anti-interference capability and improving linear range. The invention can be used for precise measurement in such fields as micro-electronics, materials, industrial precise detection, biomedicine, etc.

Description

technical field [0001] The invention belongs to the technical field of optical precision measurement and can be used for precision measurement in the fields of microelectronics, materials, industrial precision detection, biomedicine and the like. technical background [0002] American scholar M.Minsky first proposed the idea of ​​confocal microscope in 1957, and obtained the US patent in 1961, the patent number is US3013467. The confocal microscope places the point light source, point object, and point detector in corresponding conjugate positions, forming a point illumination and point detection microscopic imaging system with unique tomographic capabilities in optical microscopic imaging. [0003] The tomographic imaging capability of a confocal microscope is determined by the full width at half maximum (FWHM) of its axial response curve, and FWHM is proportional to the wavelength λ of the light wave and inversely proportional to the square of the numerical aperture NA of ...

AI Technical Summary

Problems solved by technology

[0006] To sum up, the measurement methods based on the traditional coaxial confocal microscopy technology generally have the problem that the size of the objective lens and the system resolution cannot be well balanced. If the system resolution is improved by increasing the numerical aperture of the objective lens, it will The size of the objective lens increases, the working distance of the system decreases, and it is not easy to miniaturize

The dual-axis structure that symmetrically arranges the illumination optical path and the measurement optical path on both sides of the normal of the measurement surface can effectively balance the space size of the entire confocal system, but the design of its single detector is still not conducive to eliminating the light intensity drift of the light source. Common mode noise such as electronic drift of detectors and detectors, and does not have the capabilities of absolute position targeting and bipolar tracking

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