Phase conjugate reflection bi-pass lighting confocal microscopic device

Abstract

The invention discloses a phase conjugate reflection bi-pass lighting confocal microscopic device, belonging to an optics measuring microtechnique. A collimation beam expander and a spectroscope are configured on a laser direct light path in sequence; a focusing objective lens and a three-dimensional micrometric displacement objective table are configured on a spectroscope reflecting light path; a collecting objective lens is configured on a spectroscope transmission light path; a collecting objective lens converging light is conducted to a photoelectric detector through conduction optical fibers; an ellipsoid reflecting lens is also configured on the spectroscope reflecting light path; a near focus of the ellipsoid reflecting lens is located on a surface of a sample put on the three-dimensional micrometric displacement objective table; and a phase conjugate reflecting lens is configured at a remote focus of the ellipsoid reflecting lens. According to the device, bi-pass lighting to a large curvature convex surface is carried out by adopting a characteristic that a reflection ray as a phase conjugate light wave of an incidence light of the phase conjugate reflecting lens can go back along an original way in combination with a characteristic that the ellipsoid reflecting lens is provided with a pair of isoplanatic image formation conjugate focuses, so that the device has a measurement ability of the large curvature convex surface and a characteristic of a high axial resolution force.

Description

technical field [0001] The invention belongs to optical microscopic measurement technology, and mainly relates to an ultra-precise measuring instrument for three-dimensional microstructure, microstep, microgroove line width, depth and surface shape measurement in microstructured optical elements, microstructured mechanical elements, and integrated circuit elements. Non-contact measuring device. Background technique [0002] Confocal scanning measurement is one of the important technical means to measure three-dimensional microstructure, micro-step, micro-groove line width, depth and surface shape in the fields of micro-optics, micro-mechanics and micro-electronics. The basic idea is to introduce a pinhole detector Stray light is suppressed and axial tomography capability is produced, but traditional confocal technology has always been limited by the principle that the numerical aperture of traditional lens imaging is less than 1. [0003] Double-pass illumination confocal m...

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Problems solved by technology

[0004] The lack of commonality between the existing double-pass illumination confocal measurement method and the confocal measurement method proposed by Minsky is that when measuring a surface with a large curvature, the reflected measurement light exceeds the collection aperture of the collecting objective lens due to the change of the surface normal direction, so , the system will not be able to measure large curvature surfaces

At the same time, the system resolution is also closely related to the numerical aperture of the collecting objective lens. The larger the numerical aperture, the higher the axial resolution. However, due to the limitation of the principle that the imaging numerical aperture of the traditional lens is less than 1, it is difficult for both of them to increase the numerical aperture. Aperture to further improve axial resolution

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