Post-focusing optical microscopic system

Abstract

The invention discloses a post-focusing optical microscopic system, and relates to the technical field of optical focusing, the post-focusing optical microscopic system comprises an objective lens group, a spectroscope, an imaging lens group and an image sensor, the objective lens group is used for collecting light emitted or reflected by a measured object and carrying out preliminary focusing; the spectroscope is used for decomposing light collected by the objective lens group into a plurality of monochromatic light, and the imaging lens group is used for secondarily focusing the monochromatic light decomposed by the spectroscope and projecting the monochromatic light onto the image charging sensor for optical imaging; wherein the number of imaging lenses in the imaging lens group is N, and when the distance between the measured object and the objective lens group deviates, any one imaging lens in the imaging lens group is moved, so that a microscopic image of the measured object is focused on the image sensor; the moving distance of the imaging lens and the object distance offset of the measured object are in a linear relation. According to the invention, the problems of complex structure and slow response speed of an optical microscopic system based on a focusing mode of integral lens group movement in the prior art are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical focusing technology, and particularly relates to a rear focusing optical microscopic system. BACKGROUND

[0002] The optical microscopic system is an imaging device for magnifying micro objects by using optical lenses, and is widely used in the fields of biomedical science, material science, electronic manufacturing, precision engineering and education and scientific research. By adjusting the positions of the optical elements in the optical path, the optical microscopic system can realize clear observation and analysis of the sample under different magnifications, and is one of the indispensable core devices in the research of the micro world.

[0003] In the prior art, the traditional optical microscopic system mainly adopts the focusing mode of moving the whole lens group. This focusing mode generally moves the objective lens or the eyepiece lens group along the optical axis direction by mechanical structure, so as to change the object distance or the image distance to realize clear imaging of the image. However, this method is relatively mature in technology, but still has some obvious defects. On the one hand, the focusing mode of moving the whole lens group depends on complex mechanical structure, such as slide rail, gear set, fine adjustment screw rod and the like, which not only increases the overall volume and manufacturing cost of the system, but also puts forward higher requirements for the structure precision and assembly process. On the other hand, due to the large mass of the whole lens group, the inertia in the moving process is strong, which leads to relatively slow response speed, and it is difficult to meet the application requirements of high frequency imaging or real-time adjustment.

[0004] It can be seen that the focusing mode of the optical microscopic system in the prior art based on moving the whole lens group has the problems of complex structure and slow response speed. SUMMARY

[0005] The present application aims to provide a rear focusing optical microscopic system, which solves the problems of complex structure and slow response speed of the focusing mode of the optical microscopic system in the prior art based on moving the whole lens group.

[0006] To achieve this purpose, the present application adopts the following technical solutions: A rear focusing optical microscopic system, comprising an objective lens group, a light splitting mirror, an imaging lens group and an image sensor which are sequentially arranged along the optical axis direction, and a measured object is located on one side of the objective lens group; The objective lens group is used for collecting the light emitted or reflected by the measured object and performing preliminary focusing; the light splitting mirror is used for decomposing the light collected by the objective lens group into several monochromatic lights; and the imaging lens group is used for performing secondary focusing on the several monochromatic lights decomposed by the light splitting mirror, and projecting the several monochromatic lights on the image sensor for optical imaging; The number of the image-forming lenses in the image-forming lens group is N. When the distance between the object and the objective lens group is offset, any one of the image-forming lenses in the image-forming lens group is moved to focus the microscopic image of the object on the image sensor; the moving distance of the image-forming lens and the object distance offset of the object are in a linear relationship.

[0007] Optionally, the number of the image-forming lenses in the image-forming lens group is three, the image-forming lens group comprises a first image-forming lens, a second image-forming lens and a third image-forming lens arranged in sequence along the optical axis, the first image-forming lens is arranged adjacent to the light splitting mirror, and the third image-forming lens is arranged adjacent to the image sensor.

[0008] Optionally, the moving any one of the image-forming lenses in the image-forming lens group specifically includes the following three working states: The first working state is to move the first image-forming lens, and the second image-forming lens and the third image-forming lens are stationary; The second working state is to move the second image-forming lens, and the first image-forming lens and the third image-forming lens are stationary; The third working state is to move the third image-forming lens, and the first image-forming lens and the second image-forming lens are stationary.

[0009] Optionally, the range of the object distance offset of the object is ±0.1 to ±1 mm.

[0010] Optionally, the objective lens group comprises a first objective lens, a second objective lens, a third objective lens and a fourth objective lens arranged in sequence along the optical axis, the first objective lens is located between the object and the second objective lens, and the fourth objective lens is located between the third objective lens and the light splitting mirror.

[0011] Optionally, the moving distance of the image-forming lens is calculated by the following formula: ; In the formula, y is the moving distance of the image-forming lens, mm, the direction close to the image sensor is positive, and the direction away from the image sensor is negative; k is a constant, unitless; Δ x is the object distance offset of the object, mm, the direction away from the objective lens group is positive, and the direction close to the objective lens group is negative.

[0012] Optionally, the image sensor is a CMOS or CCD sensor.

[0013] Optionally, based on the linear relationship between the moving distance of the imaging mirror and the object distance offset of the object under test, any one of the imaging mirrors in the imaging mirror group is moved by a motor so that the microscopic image of the object under test is focused on the image sensor.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a post-focusing optical microscopy system that achieves image focusing by moving any one of the imaging mirrors in an imaging mirror group. This avoids the complex mechanical structures required for moving the entire lens group in traditional systems, simplifying the system structure, reducing size and manufacturing costs, and facilitating miniaturization. Since only a single, relatively small imaging mirror needs to be moved, it has less inertia and a faster response speed compared to moving the entire lens group, meeting the application requirements of high-frequency imaging or real-time focusing, and improving focusing efficiency and image quality. Because the moving distance of the imaging mirror is linearly related to the object distance offset of the measured object, it is beneficial to use linear control algorithms for precise focusing, facilitating automated control and making it suitable for integrated, highly intelligent microscopic imaging systems. This invention eliminates the need for moving the entire lens group for focusing; instead, it uses the movement of a single mirror, reducing mechanical vibration and wear during system operation, improving operational stability and long-term reliability. Therefore, this invention solves the problems of complex structure and slow response speed in existing optical microscopy systems based on moving the entire lens group for focusing. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0017] Fig. 1 This is a schematic diagram of the structure of a post-focusing optical microscopy system provided in an embodiment of the present invention; Fig. 2 A schematic diagram illustrating the movement of a second imaging mirror in a post-focusing optical microscopy system provided in an embodiment of the present invention; Fig. 3 This is a schematic diagram illustrating the linear relationship between the moving distance of the second imaging mirror and the object distance offset of the measured object in a post-focusing optical microscopy system provided in an embodiment of the present invention.

[0018] Illustration: 001. Object under test; 100. Objective lens group; 110. First objective lens; 120. Second objective lens; 130. Third objective lens; 140. Fourth objective lens; 200. Beam splitter; 300. Imaging lens group; 310. First imaging lens; 320. Second imaging lens; 330. Third imaging lens; 400. Image sensor. Detailed Implementation

[0019] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0020] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the connection.

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] This invention provides a post-focusing optical microscopy system, such as... Figs. 1-3 As shown, it includes an objective lens group 100, a beam splitter 200, an imaging lens group 300 and an image sensor 400 arranged sequentially along the optical axis, with the object under test 001 located on one side of the objective lens group 100. The objective lens group 100 is used to collect the light emitted or reflected by the object under test 001 and perform preliminary focusing; the beam splitter 200 is used to decompose the light collected by the objective lens group 100 into several monochromatic lights; the imaging lens group 300 is used to perform secondary focusing of the several monochromatic lights after being decomposed by the beam splitter 200 and project them onto the image sensor for optical imaging. In this configuration, the number of imaging mirrors in the imaging mirror group 300 is N. When the distance between the object under test 001 and the objective lens group 100 shifts, the microscopic image of the object under test 001 is focused onto the image sensor 400 by moving any one of the imaging mirrors in the imaging mirror group 300. The moving distance of the imaging mirror is linearly related to the object distance shift of the object under test 001. The image sensor 400 is a CMOS or CCD sensor.

[0023] It should be noted that the post-focusing optical microscopy system provided by this invention achieves image focusing by moving any one of the imaging mirrors in the imaging mirror group 300, avoiding the complex mechanical structure required for moving the entire lens group in traditional methods. This simplifies the system structure, reduces size and manufacturing costs, and facilitates miniaturization. Since only a single, relatively small imaging mirror needs to be moved, it has less inertia and a faster response speed compared to moving the entire lens group, meeting the application requirements of high-frequency imaging or real-time focusing, and improving focusing efficiency and image quality. Because the moving distance of the imaging mirror is linearly related to the object distance offset of the measured object 001, it is beneficial to use linear control algorithms for precise focusing, facilitating automated control and making it suitable for integrated, highly intelligent microscopic imaging systems. This invention eliminates the need for moving the entire lens group for focusing; instead, it uses the movement of a single mirror, reducing mechanical vibration and wear during system operation, improving operational stability and long-term reliability. Therefore, this invention solves the problems of complex structure and slow response speed in existing optical microscopy systems based on moving the entire lens group for focusing.

[0024] like Fig. 1 As shown, the number of imaging mirrors in the imaging mirror group 300 is three. The imaging mirror group 300 includes a first imaging mirror 310, a second imaging mirror 320 and a third imaging mirror 330 arranged sequentially along the optical axis. The first imaging mirror 310 is arranged adjacent to the beam splitter 200 and the third imaging mirror 330 is arranged adjacent to the image sensor 400.

[0025] In practical implementation, since the first imaging mirror 310, the second imaging mirror 320, and the third imaging mirror 330 are arranged sequentially along the optical axis, they can effectively achieve step-by-step focusing of light, thereby improving the clarity and resolution of the microscopic image and ensuring that the imaging information received by the image sensor 400 is more accurate. At the same time, the optical path layout is optimized, reducing unnecessary optical components and complex optical adjustments, enhancing the stability of the entire microscopic system. This design reduces the influence of external interference, ensuring long-term stable image imaging results. The first imaging mirror 310, the second imaging mirror 320, and the third imaging mirror 330 can be flexibly adjusted in practical applications, improving the adjustability and maintainability of the optical system, and making it suitable for occasions with different magnifications and imaging requirements.

[0026] likeFigs. 1-3 As shown, by moving any one of the imaging mirrors in the imaging mirror group 300, the following three working states are specifically included: The first working state is that the first imaging mirror 310 is moved while the second imaging mirror 320 and the third imaging mirror 330 remain stationary. The second working state is as follows: the second imaging mirror 320 is moved, while the first imaging mirror 310 and the third imaging mirror 330 remain stationary. In this embodiment, when the object distance offset of the measured object 001 is -0.36mm, the moving distance d of the second imaging mirror 320 is -0.1mm; when the object distance offset of the measured object 001 is -1.44mm, the moving distance d of the second imaging mirror 320 is -0.4mm; when the object distance offset of the measured object 001 is 0.72mm, the moving distance d of the second imaging mirror 320 is 0.2mm; and when the object distance offset of the measured object 001 is 1.08mm, the moving distance d of the second imaging mirror 320 is 0.3mm. The third working state is that the third imaging mirror 330 is moved, while the first imaging mirror 310 and the second imaging mirror 320 remain stationary. In this embodiment, the first imaging mirror 310 and the second imaging mirror 320 are both single mirrors, and the third imaging mirror 330 is a cemented doublet mirror. Specifically, along the optical path from the object under test 001 to the image sensor 400, the first surface of the first imaging mirror 310 has a radius of curvature of -18.47 mm and a refractive index of 1.85; the second surface of the first imaging mirror 310 has a radius of curvature of -22.14 mm and a thickness of 3 mm; the first surface of the second imaging mirror 320 has a radius of curvature of 170.65 mm and a radius of curvature of -46.89 mm; the thickness of the second imaging mirror 320 is 5.1 mm and a refractive index of 1.7; the first surface of the third imaging mirror 330 has a radius of curvature of 26.37 mm and a refractive index of 1.7; the second surface of the third imaging mirror 330 has a radius of curvature of -76.6 mm and a refractive index of 1.81; and the third surface of the third imaging mirror 330 has a radius of curvature of 19.47 mm.

[0027] It should be noted that by designing three independent working states, any one of the first imaging mirror 310, the second imaging mirror 320, or the third imaging mirror 330 can be moved separately to achieve precise focusing of the microscopic image. This provides excellent flexibility and scalability, allowing the selection of the optimal focusing scheme based on specific imaging requirements or structural layout. In each working state, only a single imaging mirror needs to be moved, while the others remain fixed, greatly simplifying the structural design of the focusing actuator, reducing the complexity and power consumption of the drive system, and facilitating the realization of a miniaturized, low-cost, and highly reliable microscopic system. Based on the differences in the imaging optical path caused by the different mirror positions, the user can select to move the mirror closer to the object 001 or the image sensor 400 in the optical path, thereby obtaining higher focusing sensitivity and accuracy, suitable for imaging scenarios with different depth ranges or large variations in object distance.

[0028] In one embodiment, since the object distance offset of the measured object 001 is in the range of ±0.1~±1mm, effective focusing can be achieved within this range by moving any imaging lens. This can meet the small object distance offset caused by stage vibration, sample thickness change or clamping error during the imaging process of different types of samples such as common biological samples, microelectronic devices, and material surfaces, and has strong practical adaptability.

[0029] In one embodiment, the objective lens group 100 includes a first objective lens 110, a second objective lens 120, a third objective lens 130 and a fourth objective lens 140 arranged sequentially along the optical axis. The first objective lens 110 is located between the object under test 001 and the second objective lens 120, and the fourth objective lens 140 is located between the third objective lens 130 and the beam splitter 200.

[0030] Specifically, the moving distance of the imaging mirror is calculated using the following formula: ; In the formula, y The moving distance of the imaging mirror is in mm. The direction closer to the image sensor 400 is positive, and the direction farther away from the image sensor 400 is negative. k is a constant with no unit; the value of k is determined by the optical path design parameters of the optical microscope system. Δ x This represents the object distance offset of the measured object 001, in mm. The direction away from objective lens group 100 is positive, and the direction closer to objective lens group 100 is negative.

[0031] In one embodiment, based on the linear relationship between the moving distance of the imaging mirror and the object distance offset of the object under test 001, any one of the imaging mirrors in the imaging mirror group 300 is moved by a motor to focus the microscopic image of the object under test 001 onto the image sensor 400. In this embodiment, the first imaging mirror 310, the second imaging mirror 320, and the third imaging mirror 330 are each controlled by an independent motor.

[0032] It should be noted that since the moving distance of the imaging lens is linearly related to the object distance offset of the measured object 001, it is easy to establish a precise mathematical model for focusing control, thereby achieving fast and stable autofocus and meeting the focusing accuracy requirements of high-resolution microscopy. By configuring independent motor drives for the first imaging lens 310, the second imaging lens 320, and the third imaging lens 330, any one of the imaging lenses can be selected for movement according to imaging needs, without the need for overall adjustment of the imaging lens group 300 structure. This makes the system control more flexible and modular, suitable for various microscopic scenarios. Since only a single lens is driven at a time, and a precise motor drive is used, structural disturbances to the entire objective lens group 100 are reduced, which helps improve the system stability during the imaging process and avoids image blurring or shifting due to mechanical vibration.

[0033] In another embodiment, it is worth mentioning that the present invention also provides a focusing method applied to the post-focusing optical microscope system provided in the embodiments of the present invention, comprising: Step S1: Real-time detection of the object distance offset Δ between the object under test 001 and the objective lens group 100. x In this embodiment, the object distance offset can be obtained using a laser rangefinder or an image contrast analysis module known in the art.

[0034] Step S2, based on the object distance offset Δ x The amplitude and direction are dynamically selected to move the imaging mirror in the imaging mirror group 300; in this embodiment, when At that time, the third imaging mirror 330 is moved because small displacements result in higher sensitivity to the end optical path; when At that time, the second imaging mirror 320 is moved to balance the sensitivity with the movement stroke of the imaging mirror; when At this time, the first imaging mirror 310 is moved to reduce the impact of large displacement on the end of the imaging optical path. Additionally, when... First, move the objective lens group 100 to perform coarse focusing; then, move the imaging lens to perform fine focusing.

[0035] Step S3, based on the object distance offset Δ x Calculate the distance the selected imaging mirror should move. y The movement command is then sent to the corresponding drive mechanism; wherein the movement distance... yThrough linear functions y =k*Δ x The calculation shows that k is a constant pre-calibrated according to the optical system structure. In this embodiment, the drive mechanism is driven by a micro motor.

[0036] Step S4: Drive the selected imaging mirror to move along the optical axis to the target position. y The system monitors the image sharpness index in real time to see if it reaches a preset threshold. If not, it continues micro-oscillation scanning; if it has reached the threshold, it maintains the current lens position and ends the focusing process. After focusing is complete, the system will monitor the current lens position and Δ... x The values ​​are stored for quick reference and optimization during subsequent imaging processes, improving autofocus response speed and reproducibility.

[0037] In specific implementation, the micro-oscillation scanning in step S4 includes: using the target position y as a reference, generating 3 scanning points with a displacement of ±5%, and selecting the displacement corresponding to the maximum value of the image clarity index.

[0038] It should be noted that, in order to improve focusing accuracy, step S4 uses the image sharpness index fed back by the image sensor 400 to perform micro-oscillation scanning, thereby realizing a closed-loop control strategy that coordinates distance calculation and perception; the built-in image sharpness evaluation module of the microscope system analyzes the image (such as using algorithms such as Sobel transform, contrast, and spectral energy).

[0039] After step S4 is completed, if there is still a significant color difference at the image edge (such as blue channel blurring, purple fringing, etc.), the system enters the multi-lens collaborative anti-chromatic aberration mode; this mode moves the selected imaging lens adjacent to another imaging lens in a coordinated manner to collaboratively correct the color difference.

[0040] This focusing method also includes: Step S5: Let y_actual be the actual displacement of the imaging mirror selected in step S4, and move the other imaging mirror adjacent to the selected imaging mirror in conjunction to collaboratively correct chromatic aberration. In this embodiment, the displacement of the other imaging mirror that is moved in conjunction is calculated using the following formula: ; In the formula, α is the displacement ratio factor of the linkage lens relative to the main focusing lens, which is a dimensionless adjustment parameter that takes a value between (0,1). In this embodiment, the value of α is dynamically adjusted according to the optimization results of the color difference evaluation function (such as CIE-Lab color difference) to ensure that the focus positions of the RGB channels are consistent after focusing, thereby reducing axial or lateral color difference. In the specific implementation process, by using the ΔE value in the CIE-Lab color difference model as the optimization objective function, α is iteratively optimized multiple times until the image sharpness in the R, G, and B channels simultaneously reaches the set threshold, thereby completing the collaborative fine focusing of multiple lenses.

[0041] It should be noted that different lenses have different focusing sensitivities for different wavelengths. By linking adjacent lenses, the focus positions of the three RGB channels can be made more consistent, thereby suppressing chromatic aberration. The specific optimization process is as follows: initially, an α value is given, the auxiliary lens is moved, then three-channel images are acquired, and the ΔE chromatic aberration value is calculated. If the ΔE value decreases, optimization continues; otherwise, the α value is adjusted, and iteration continues until the ΔE value reaches its minimum or is below a set threshold. The adjusted system can achieve clear focus simultaneously in all three color channels, significantly reducing axial and lateral chromatic aberration. Specifically, step S5 is a closed-loop chromatic aberration correction step: first, the main lens is used for focusing, then adjacent lenses are linked proportionally, and the proportion is dynamically adjusted using the quantitative index of color difference until the three colors are focused consistently. This not only improves the image clarity but also makes the color reproduction of the microscopic image closer to reality.

[0042] Working Principle: This invention provides a post-focusing optical microscopy system that achieves image focusing by moving any one of the imaging mirrors in the imaging mirror group 300. This avoids the complex mechanical structure required for moving the entire lens group in traditional systems, simplifying the system structure, reducing size and manufacturing costs, and facilitating miniaturization. Since only a single, relatively small imaging mirror needs to be moved, it has less inertia and a faster response speed compared to moving the entire lens group, meeting the application requirements of high-frequency imaging or real-time focusing, and improving focusing efficiency and image quality. Because the moving distance of the imaging mirror is linearly related to the object distance offset of the measured object 001, it is beneficial to use linear control algorithms for precise focusing, facilitating automated control and making it suitable for integrated, highly intelligent microscopic imaging systems. This invention eliminates the need for moving the entire lens group for focusing; instead, it uses the movement of a single mirror, reducing mechanical vibration and wear during system operation, improving operational stability and long-term reliability. Therefore, this invention solves the problems of complex structure and slow response speed in existing optical microscopy systems based on moving the entire lens group for focusing.

[0043] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A post-focusing optical microscopy system, characterized in that, It includes an objective lens group (100), a beam splitter (200), an imaging lens group (300), and an image sensor (400) arranged sequentially along the optical axis, with the object under test (001) located on one side of the objective lens group (100); The objective lens group (100) is used to collect the light emitted or reflected by the object under test (001) and perform preliminary focusing; the beam splitter (200) is used to decompose the light collected by the objective lens group (100) into several monochromatic lights, and the imaging lens group (300) is used to perform secondary focusing on the several monochromatic lights decomposed by the beam splitter (200) and project them onto the image sensor for optical imaging; In this configuration, the number of imaging mirrors in the imaging mirror group (300) is N. When the distance between the object under test (001) and the objective lens group (100) shifts, the microscope image of the object under test (001) is focused onto the image sensor (400) by moving any one of the imaging mirrors in the imaging mirror group (300). The moving distance of the imaging mirror and the object distance shift of the object under test (001) are linearly related.

2. The post-focusing optical microscope system according to claim 1, characterized in that, The imaging mirror group (300) contains three imaging mirrors. The imaging mirror group (300) includes a first imaging mirror (310), a second imaging mirror (320), and a third imaging mirror (330) arranged sequentially along the optical axis. The first imaging mirror (310) is arranged adjacent to the beam splitter (200), and the third imaging mirror (330) is arranged adjacent to the image sensor (400).

3. The post-focusing optical microscope system according to claim 2, characterized in that, The process of moving any one of the imaging mirrors in the imaging mirror group (300) specifically includes the following three working states: The first working state is that the first imaging mirror (310) is moved, while the second imaging mirror (320) and the third imaging mirror (330) remain stationary; The second working state is that the second imaging mirror (320) is moved while the first imaging mirror (310) and the third imaging mirror (330) remain stationary. The third working state is that the third imaging mirror (330) is moved while the first imaging mirror (310) and the second imaging mirror (320) remain stationary.

4. The post-focusing optical microscope system according to claim 1, characterized in that, The object distance offset of the measured object (001) is in the range of ±0.1~±1mm.

5. The post-focusing optical microscopy system according to claim 1, characterized in that, The objective lens group (100) includes a first objective lens (110), a second objective lens (120), a third objective lens (130) and a fourth objective lens (140) arranged sequentially along the optical axis. The first objective lens (110) is located between the object under test (001) and the second objective lens (120), and the fourth objective lens (140) is located between the third objective lens (130) and the beam splitter (200).

6. The post-focusing optical microscope system according to any one of claims 1 to 5, characterized in that, The moving distance of the imaging mirror is calculated using the following formula: ； In the formula, y The moving distance of the imaging mirror is in mm. The direction closer to the image sensor (400) is a positive value, and the direction farther away from the image sensor (400) is a negative value. k is a constant and has no unit; Δ x The distance offset of the object (001) is measured in mm. The direction away from the objective lens group (100) is positive and the direction closer to the objective lens group (100) is negative.

7. The post-focusing optical microscopy system according to claim 1, characterized in that, The image sensor (400) is a CMOS or CCD sensor.

8. The post-focusing optical microscope system according to any one of claims 1 to 5 or 7, characterized in that, Based on the linear relationship between the moving distance of the imaging mirror and the object distance offset of the object under test (001), any one of the imaging mirrors in the imaging mirror group (300) is moved by a motor so that the microscopic image of the object under test (001) is focused on the image sensor (400).

Images