Radial polarized lighting ellipsoidal surface pupil amplitude filtering confocal imaging device

Abstract

The invention discloses a radial polarized lighting ellipsoidal surface pupil amplitude filtering confocal imaging device which belongs to the optical microscope measurement field. After passing through a collimated beam expander, a polarizer, a radial polarized converter and a spectroscope in sequence, laser beams emitted by a laser of the confocal imaging device are converged onto the surface of an ellipsoidal reflector by an objective lens with large numerical aperture, are returned along a symmetric path after being reflected twice by the ellipsoidal reflector and a sample, and are reflected when passing through the spectroscope again. The reflected beams are firstly converged by a coupling lens, and are transmitted to a photomultiplier through an optical fiber for imaging. The focus of the objective lens with large numerical aperture overlaps with the distal focus F1 of the ellipsoidal reflector; and the proximal focus F2 of the ellipsoidal reflector is located on the surface of the sample. The ellipsoidal reflector is in a zonal structure; the reflectivity of two separated zones is identical; and the reflectivity of two adjacent zones is respectively 0 and 1. By using the confocal imaging device disclosed by the invention, the transverse resolution can be improved, and the ratio of the maximum axial electric energy current density to the maximum radial electric energy current density at the focus can be increased.

Description

technical field [0001] The radial polarized illumination ellipsoidal curved surface pupil amplitude filter confocal imaging device belongs to the field of optical microscope measurement; it mainly relates to an ultra-precise non-contact measurement device for measuring the surface topography of three-dimensional fine structures in microstructure industrial samples. Background technique [0002] Confocal scanning measurement is one of the main technical means to measure three-dimensional fine structure, micro-step, micro-groove line width, depth and surface shape in the fields of micro-optics, micro-mechanics and micro-electronics. Including differential confocal curvature radius measurement method and device (public number CN101526341), confocal microscope and its height measurement method (public number CN1392962), polychromatic super-resolution differential confocal measurement method and device (public number CN101182992) The lateral resolution of the confocal scanning me...

AI Technical Summary

Problems solved by technology

For this type of confocal scanning measurement system using traditional lens illumination and detection structures, the theoretical limit of the convergence angle of the objective lens composed of lens groups is 90°. However, the harsh processing technology and complex lens group structure make the maximum practical commercial dry objective The convergence angle is limited to 72° (corresponding to a numerical aperture of 0.95 and a refractive index of 1), so it is difficult for a confocal scanning system using a traditional lens illumination and detection structure to improve resolution by increasing the numerical aperture

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