Dark-Field Fourier Light Field Microscopic Measurement Device and Method Based on Angular Illumination

Abstract

The present invention discloses a dark-field Fourier light field microscopic measurement device and method based on angular illumination, comprising: an inclined beam illumination module, an x-direction dark-field Fourier light field detection module, a y-direction dark-field Fourier light field detection module, and a z-direction dark-field Fourier light field detection module; the inclined beam illumination module is used for transferring, splitting, and focusing the light fields of a series of uncorrelated illumination beams, irradiating the sample to be measured with the illumination beams at an inclination angle α to achieve inclined illumination and form scattered light in the x, y, and z directions; the x, y, and z-direction dark-field Fourier light field detection modules are used for respectively collecting, Fourier light field decomposing, and collecting image signals of the scattered light in the corresponding three directions, and performing calculation and reconstruction through a light field refocusing algorithm; by analyzing the dark-field Fourier light field information, a high-contrast dark-field image is reconstructed to achieve rapid reconstruction of a three-dimensional sample; and the resolution in each direction is made consistent by using the collected scattered signals.

Description

Technical Field

[0001] The present invention relates to the technical field of optical precision measurement, and more particularly to a dark field Fourier light field microscopic measurement device and method based on angle illumination. Background Art

[0002] At present, high-performance optical components and optical materials are widely used in precision instrument manufacturing and major optical engineering research, and are the foundation of optical system performance. At the same time, in order to be suitable for use under high throughput, the aperture of the optical components used in the device is relatively large, usually in the meter range. Therefore, it plays an important role in high-speed and high-resolution precision detection of contamination defects and lattice structural defects on the surface and sub-surface of large-aperture optical components and optical materials; among them, the sub-surface defect structure of the optical component will have a serious impact on the light field distribution of the outgoing light beam, reduce the spot quality, and affect the service life of the optical component.

[0003] Dark-field microscopy has the advantages of high imaging speed and high imaging contrast brought by dark background, and has become an important means of non-destructive testing of optical components. However, ordinary optical dark-field microscopy based on oblique illumination can only achieve two-dimensional imaging of samples and detect surface geometric defects such as scratches and bubbles, but it cannot obtain the three-dimensional characteristics of defects and accurately locate defects. In order to more comprehensively characterize the defect characteristics of optical components and materials, and to more accurately identify and classify defects, microscopy methods integrating multiple modes have been more widely used in the field of defect measurement. However, high-speed detection of defect signals of large-caliber samples is still not possible.

[0004] Therefore, how to provide a dark-field Fourier light-field microscopy measurement device and method based on angle illumination to achieve rapid three-dimensional imaging of samples is a problem that technicians in this field urgently need to solve. Summary of the invention

[0005] In view of this, the present invention provides a dark-field Fourier light-field microscopy measurement device and method based on angle illumination, which realizes rapid reconstruction of three-dimensional samples and achieves the function of consistent resolution of three-dimensional morphology measurement of samples in all directions.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A dark field Fourier light field microscopic measurement method based on angle illumination comprises the following steps:

[0008] S1. A series of unrelated illumination beams are switched, split and focused, and the illumination beams are irradiated on the sample to be tested at an inclination angle α to achieve oblique illumination and form scattered light in the x, y and z directions;

[0009] S2. The scattered light in the corresponding three directions is respectively collected, Fourier optical field decomposed, and the image signal is collected by the dark-field Fourier optical field detection modules in the x, y, and z directions, and the dark-field image is obtained through calculation and reconstruction by the optical field refocusing algorithm.

[0010] S3. Analyze the dark-field images obtained in the x, y, and z directions, perform three-dimensional reconstruction, and perform three-dimensional topography measurement with consistent resolution in each direction on the sample.

[0011] Preferably, the specific content of S2 includes: collecting the scattered light in the x direction through the first collecting objective lens, passing through the third and fourth tube lenses, performing Fourier optical field decomposition through the first microlens array, and calculating and reconstructing the signal collected by the first image acquisition CCD through the optical field refocusing algorithm to obtain the dark-field image.

[0012] Preferably, the specific content of S2 further includes: collecting the scattered light in the y direction through the second collecting objective lens, passing through the fifth and sixth tube lenses, performing Fourier optical field decomposition through the second microlens array, and calculating and reconstructing the signal collected by the second image acquisition CCD through the optical field refocusing algorithm to obtain the dark-field image.

[0013] Preferably, the specific content of S2 further includes: collecting the scattered light in the z direction through the third collecting objective lens, passing through the seventh and eighth tube lenses, performing Fourier optical field decomposition through the third microlens array, and calculating and reconstructing the signal collected by the third image acquisition CCD through the optical field refocusing algorithm to obtain the dark-field image.

[0014] A dark-field Fourier optical field microscopic measurement device based on angular illumination includes: an inclined beam illumination module, a dark-field Fourier optical field detection module in the x direction, a dark-field Fourier optical field detection module in the y direction, and a dark-field Fourier optical field detection module in the z direction;

[0015] The inclined beam illumination module is used to transfer, split, and focus the optical field of a series of uncorrelated illumination beams. The illumination beams are incident on the sample to be measured at an inclination angle α to achieve inclined illumination and form scattered light in the x, y, and z directions;

[0016] The dark-field Fourier optical field detection modules in the x, y, and z directions are used to respectively collect, Fourier optical field decompose, and collect the image signal of the scattered light in the corresponding three directions, and obtain the dark-field image through calculation and reconstruction by the optical field refocusing algorithm.

[0017] Preferably, a dark-field Fourier optical field microscopic measurement device based on angular illumination further includes a terminal measurement module, which is used to analyze the dark-field images obtained in the x, y, and z directions, perform three-dimensional reconstruction, and perform three-dimensional topography measurement with consistent resolution in each direction on the sample.

[0018] Preferably, the x-direction dark-field Fourier light field detection module sequentially includes, in the light propagation direction: a collecting objective lens I, a tube lens III, a tube lens IV, a microlens array I, and an image acquisition CCD I.

[0019] Preferably, the y-direction dark-field Fourier light field detection module sequentially includes, in the light propagation direction: a collecting objective lens II, a tube lens V, a tube lens VI, a microlens array II, and an image acquisition CCD II.

[0020] Preferably, the z-direction dark-field Fourier light field detection module sequentially includes, in the light propagation direction: a collecting objective lens III, an aperture stop, a tube lens VII, a tube lens VIII, a microlens array III, and an image acquisition CCD III.

[0021] Preferably, the tilted beam illumination module sequentially includes, in the light propagation direction: an annular LED array, a tube lens I, a tube lens II, a focusing objective lens, and a sample to be measured.

[0022] As can be seen from the above technical solutions, compared with the prior art, the present invention discloses a dark-field Fourier light field microscopic measurement device and method based on angular illumination. By analyzing the dark-field Fourier light field information after illumination by the annular LED array, a high-contrast dark-field image is reconstructed to achieve rapid reconstruction of a three-dimensional sample; using the scattered signals collected in three directions for correlation calculation, the resolution in each direction can be made consistent. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0024] Figure 1 The drawings are a schematic structural diagram of a dark-field Fourier light field microscopic measurement device based on angular illumination provided by the present invention;

[0025] Among them, 1 - annular LED array, 2 - tube lens I, 3 - tube lens II, 4 - focusing objective lens, 5 - sample to be measured, 6 - collecting objective lens I, 7 - tube lens III, 8 - tube lens IV, 9 - microlens array I, 10 - image collecting CCD I, 11 - collecting objective lens II, 12 - tube lens V, 13 - tube lens VI, 14 - microlens array II, 15 - image acquisition CCD II, 16 - collecting objective lens III, 17 - aperture stop, 18 - tube lens VII, 19 - tube lens VIII, 20 - microlens array III, 21 - image acquisition CCD III. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Embodiment 1

[0028] A dark field Fourier light field microscopic measurement method based on angle illumination comprises the following steps:

[0029] S1. A series of unrelated illumination beams are switched, split and focused, and the illumination beams are irradiated on the sample to be tested at an inclination angle α to achieve oblique illumination and form scattered light in the x, y and z directions;

[0030] S2. The dark field Fourier light field detection modules in the x, y and z directions respectively collect the scattered light in the corresponding three directions, decompose the Fourier light field and collect the image signal, and calculate and reorganize the dark field image through the light field refocusing algorithm;

[0031] S3. Analyze the dark field images obtained in the x, y and z directions, and perform 3D reconstruction to measure the 3D morphology of the sample with consistent resolution in all directions.

[0032] In order to further implement the above technical solution, the specific content of S2 includes: collecting the scattered light in the x direction through the collecting objective lens 1, passing through the tube lens 3 and the tube lens 4, performing Fourier light field decomposition through the microlens array 1, and calculating and reorganizing the signal collected by the image acquisition CCD 1 through the light field refocusing algorithm to obtain a dark field image.

[0033] In order to further implement the above technical solution, the specific content of S2 also includes: the scattered light in the y direction is collected by collecting objective lens 2, passes through tube lens 5 and tube lens 6, and is decomposed into Fourier light field by microlens array 2, and the signal collected by image acquisition CCD 2 is calculated and reorganized by light field refocusing algorithm to obtain a dark field image.

[0034] In order to further implement the above technical solution, the specific content of S2 also includes: the scattered light in the z direction is collected by collecting objective lens three, passes through tube lens seven and tube lens eight, and is decomposed into Fourier light field by microlens array three, and the signal collected by image acquisition CCD three is calculated and reorganized by light field refocusing algorithm to obtain a dark field image.

[0035] Embodiment 2

[0036] A dark-field Fourier light field microscopic measurement device based on angle illumination, such as Figure 1, including: an inclined beam illumination module, an x-direction dark-field Fourier light field detection module, a y-direction dark-field Fourier light field detection module, and a z-direction dark-field Fourier light field detection module;

[0037] The inclined beam illumination module is used to transfer, split, and focus the light fields of a series of unrelated illumination beams. The illumination beams are incident on the sample to be measured 5 at an inclination angle α to achieve inclined illumination and form scattered light in the x, y, and z directions;

[0038] The x, y, and z-direction dark-field Fourier light field detection modules are used to respectively collect, perform Fourier light field decomposition on, and collect image signals of the scattered light in the corresponding three directions, and calculate and reconstruct through the light field refocusing algorithm to obtain dark-field images.

[0039] To further implement the above technical solution, a dark-field Fourier light field microscopic measurement device based on angular illumination further includes a terminal measurement module, which is used to analyze the dark-field images obtained in the x, y, and z directions, perform three-dimensional reconstruction, and perform three-dimensional topography measurement with consistent resolution in each direction on the sample.

[0040] To further implement the above technical solution, the x-direction dark-field Fourier light field detection module sequentially includes, in the light propagation direction: a collecting objective lens 6, a tube lens 3 7, a tube lens 4 8, a microlens array 1 9, and an image acquisition CCD 1 10.

[0041] To further implement the above technical solution, the y-direction dark-field Fourier light field detection module sequentially includes, in the light propagation direction: a collecting objective lens 2 11, a tube lens 5 12, a tube lens 6 13, a microlens array 2 14, and an image acquisition CCD 2 15.

[0042] To further implement the above technical solution, the z-direction dark-field Fourier light field detection module sequentially includes, in the light propagation direction: a collecting objective lens 3 16, an aperture stop 17, a tube lens 7 18, a tube lens 8 19, a microlens array 3 20, and an image acquisition CCD 3 21.

[0043] To further implement the above technical solution, the inclined beam illumination module sequentially includes, in the light propagation direction: an annular LED array, a tube lens 1, a tube lens 2, a focusing objective lens, and a sample to be measured.

[0044] In this embodiment, the size of the microlens array is 1 - 3 mm, and the size of the CCD image plane is 3 mm.

[0045] In practical applications, the inclined beam illumination module further includes a non-polarizing beam splitter, which is disposed between the focusing objective lens and the tube lens 2.

[0046] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0047] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dark-field Fourier light field microscopy measurement method based on angular illumination, characterized in that, The following steps are involved: S1. A series of unrelated illumination beams are switched, split and focused, and the illumination beams are irradiated on the sample to be tested at an inclination angle α to achieve oblique illumination and form scattered light in the x, y and z directions; S2. The dark field Fourier light field detection modules in the x, y and z directions respectively collect the scattered light in the corresponding three directions, decompose the Fourier light field and collect the image signal, and calculate and reorganize the dark field image through the light field refocusing algorithm; S3. Analyze the dark field images obtained in the x, y and z directions, and perform three-dimensional reconstruction to measure the three-dimensional morphology of the sample with consistent resolution in all directions; The specific contents of S2 include: The scattered light in the x direction is collected by collecting objective lens 1, passes through tube lens 3 and tube lens 4, and is decomposed into a Fourier light field by microlens array 1. The signal collected by image acquisition CCD 1 is reorganized by calculation through a light field refocusing algorithm to obtain a dark field image. The scattered light in the y direction is collected by collecting objective lens 2, passes through tube lens 5 and tube lens 6, and is decomposed into Fourier light field by microlens array 2. The signal collected by image acquisition CCD 2 is reorganized by calculation through light field refocusing algorithm to obtain a dark field image. The scattered light in the z direction is collected by collecting objective lens three, passes through tube lens seven and tube lens eight, and is subjected to Fourier light field decomposition by microlens array three. The signal collected by image acquisition CCD three is computationally reorganized by a light field refocusing algorithm to obtain a dark field image.

2. A dark-field Fourier light field microscopic measurement device based on angular illumination, characterized in that include: An inclined beam illumination module, an x-direction dark field Fourier light field detection module, a y-direction dark field Fourier light field detection module, and a z-direction dark field Fourier light field detection module; The inclined beam illumination module is used to switch, split and focus a series of unrelated illumination beams. The illumination beam is irradiated on the sample to be tested at an inclination angle α to achieve inclined illumination and form scattered light in the x, y and z directions. Dark field Fourier light field detection modules in the x, y and z directions are used to collect scattered light in the corresponding three directions, decompose the Fourier light field and collect image signals, and obtain dark field images by calculating and reorganizing through the light field refocusing algorithm; The terminal measurement module is used to analyze the dark field images obtained in the x, y and z directions, and perform three-dimensional reconstruction to measure the three-dimensional morphology of the sample with consistent resolution in all directions; The inclined beam illumination module includes, in order according to the light propagation direction: a ring-shaped LED array, a tube lens 1, a tube lens 2, a focusing objective lens and a sample to be tested; The x-direction dark field Fourier light field detection module includes, in order according to the light propagation direction: a collecting objective lens 1, a tube lens 3, a tube lens 4, a microlens array 1 and an image acquisition CCD 1; The dark field Fourier light field detection module in the y direction includes, in order according to the light propagation direction: a collecting objective lens 2, a tube lens 5, a tube lens 6, a microlens array 2 and an image acquisition CCD 2; The dark field Fourier light field detection module in the z direction includes, in order according to the light propagation direction: a collecting objective lens three, an aperture diaphragm, a tube lens seven, a tube lens eight, a microlens array three and an image acquisition CCD three.

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