Huffman imaging system and time difference incubator

Abstract

The utility model provides a Hoffman imaging system and a time difference incubator, and belongs to the technical field of medical instruments. The Hoffman imaging system comprises an illumination module, an imaging module and a sample vessel. The illumination module is arranged above the sample vessel and comprises an illumination light source, a light condensation system and a shaping slit plate, the illumination light source and the light condensation system are arranged at intervals in the direction close to the sample vessel, and a slit is formed in the shaping slit plate; the imaging module is arranged below the sample vessel and comprises an objective lens, a relay lens module, an objective lens modulation plate, a lens barrel lens and an image collector which are arranged at intervals in the direction away from the sample vessel, the objective lens modulation plate is matched with the slit, and the relay lens module is detachably connected with the imaging module; the relay lens module comprises a first lens and a second lens which are arranged in a spaced mode in the light path direction. Dynamic regulation and control of imaging resolution and contrast can be realized by adjusting the slit plate and the relay lens module according to different culture samples, and adaptability and imaging quality are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of medical devices, and particularly relates to a Hoffman imaging system and a time-lapse incubator. Background Art

[0002] With the continuous growth of the demand in the assisted reproduction market, embryo culture technology has received more attention. Traditional culture methods are inefficient and require a large amount of human resources. To solve this problem, the time-lapse culture system has become an emerging method for embryo culture and screening. A time-lapse incubator can dynamically observe the development process of embryos, evaluate the development of embryos, screen out the highest-quality embryos for transplantation, thereby effectively improving the success rate of embryo culture, increasing the implantation rate, and shortening the time for patients to achieve successful pregnancy.

[0003] The microscopic imaging module in the time-lapse incubator is the most crucial part. Only by taking a three-dimensional and hierarchical biological tissue image through a camera can the morphology and development of the biological tissue be accurately judged, and the accuracy of embryo evaluation and screening be improved. In related technologies, a traditional time-lapse incubator is provided with an illumination system and an imaging system on both sides of a sample dish respectively, and corresponding lenses are provided in the illumination system and the imaging system to realize imaging of a highly transparent embryo sample by using Hoffman imaging technology.

[0004] For imaging of highly transparent embryo samples in the time-lapse incubator in related technologies, it is usually necessary to be equipped with a specially designed Hoffman objective lens. Existing Hoffman objective lenses adapted to time-lapse incubators are all integrally formed products, which are limited by product specifications, and the imaging resolution and contrast are relatively fixed. For different types and specifications of samples, it is difficult to ensure imaging quality and the adaptability is poor by using a Hoffman objective lens with a fixed specification. Summary of the Utility Model

[0005] An embodiment of the utility model provides a Hoffman imaging system and a time-lapse incubator, which can dynamically adjust the imaging resolution and contrast according to different culture samples, and improve the adaptability and imaging quality. The technical solutions are as follows:

[0006] In a first aspect, an embodiment of the utility model provides a Hoffman imaging system, including: an illumination module, an imaging module, and a sample dish,

[0007] The illumination module is arranged above the sample dish and includes an illumination light source, a shaping slit plate, and a condenser system arranged at intervals along the direction close to the sample dish. The illumination light source and the condenser system are arranged at intervals along the direction close to the sample dish, and a slit is arranged on the shaping slit plate;

[0008] The imaging module is disposed below the sample dish and includes an objective lens, a relay lens module, an objective lens modulation plate, a tube lens, and an image collector that are arranged at intervals in a direction away from the sample dish. The objective lens modulation plate is matched with the slit. The relay lens module is detachably connected to the imaging module. The relay lens module includes a first lens and a second lens that are arranged at intervals along the optical path direction. The front focal plane of the first lens coincides with the rear focal plane of the objective lens.

[0009] Optionally, the shaping slit plate is movably connected to the illumination module so as to have a first working position located at the front focal plane of the condenser system and a second working position away from the optical path; the relay lens module and the objective lens modulation plate are jointly movably connected to the imaging module so as to have a third working position located between the objective lens and the tube lens and a fourth working position away from the optical path.

[0010] Optionally, the light passing aperture of the slit is adjustable.

[0011] Optionally, a polarizer is disposed between the illumination light source and the shaping slit plate, and an analyzer matched with the polarizer is disposed at the slit of the shaping slit plate.

[0012] Optionally, the polarizer and the analyzer are in sheet form, and the relative angle between the polarizer and the shaping slit plate is adjustable.

[0013] Optionally, the slit is in a ring shape, the analyzer is in a circular shape and coaxially covers the slit, and the diameter of the analyzer is larger than the inner diameter of the slit and smaller than the outer diameter of the slit.

[0014] Optionally, the illumination light source is a light-emitting diode illumination light source, and the wavelength range of the illumination light source is 400 to 700 nm.

[0015] Optionally, the image collector is a charge-coupled device camera or a complementary metal oxide semiconductor camera.

[0016] In a second aspect, an embodiment of the present invention provides a time-lapse incubator, including the Hoffman imaging system as described in the first aspect above.

[0017] The beneficial effects brought by the technical solution provided by the embodiment of the present invention at least include:

[0018] By adopting the Hofmann imaging system provided by the embodiments of the present utility model, a shaping slit plate, a relay lens module behind the objective lens, and an objective lens modulation plate are respectively arranged in the illumination module and the imaging module, and a Hofmann imaging structure is formed by the shaping slit plate, the objective lens, the relay lens module, and the objective lens modulation plate. Compared with the conventional Hofmann objective lens, the objective lens and the objective lens modulation plate are respectively arranged outside the relay lens module. The relay lens module is used to image the rear focal plane of the objective lens, and the objective lens modulation plate is used to image outside the objective lens. That is, a standard ordinary objective lens plus a relay lens module can be used to replace the Hofmann objective lens. While ensuring the Hofmann imaging function, better imaging quality can be achieved by selecting an objective lens with better performance. Further, by separately replacing the corresponding combination of the shaping slit plate and the objective lens modulation plate, dynamic regulation of the imaging resolution and imaging contrast of the system can be realized according to different types of actual samples and imaging requirements, without being restricted by the specifications of conventional Hofmann objective lens products, reducing redundant waste of labor and equipment, and improving adaptability and imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the description of the embodiments. Obviously, the following-described drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 is a schematic structural diagram of a Hofmann imaging system provided by the embodiments of the present utility model;

[0021] Figure 2 is a schematic diagram of the imaging principle of the relay lens module provided by the embodiments of the present utility model;

[0022] Figure 3 is a schematic structural diagram of a shaping slit plate provided by the embodiments of the present utility model;

[0023] Figure 4 is provided corresponding to the embodiments of the present utility model Figure 3 is a schematic structural diagram of the objective lens modulation plate;

[0024] Figure 5 is a schematic structural diagram of another Hofmann imaging system provided by the embodiments of the present utility model;

[0025] Figure 6 is a schematic structural diagram of another shaping slit plate provided by the embodiments of the present utility model;

[0026] Figure 7 is provided corresponding to the embodiments of the present utility model Figure 6Schematic structural diagram of the objective lens modulation plate.

[0027] In the figure:

[0028] 1 - Illumination module; 2 - Imaging module; 3 - Sample dish; 11 - Illumination light source; 12 - Condensing system; 13 - Shaping slit plate; 14 - Polarizer; 15 - Analyzer; 21 - Objective lens; 22 - Relay lens module; 23 - Objective lens modulation plate; 24 - Tube lens; 25 - Image collector; 131 - Slit; 221 - First lens; 222 - Second lens. Specific embodiments

[0029] To make the objectives, technical solutions, and advantages of the present utility model clearer, the following will further describe the embodiments of the present utility model in detail with reference to the accompanying drawings.

[0030] The microscopic imaging module in the time-lapse incubator is the most crucial part. Only by taking three-dimensional and hierarchical biological tissue images through a camera can the morphology and development of biological tissues be accurately judged, and the accuracy of embryo evaluation and screening be improved. In the related art, traditional time-lapse incubators respectively set an illumination system and an imaging system on both sides of the sample dish, and corresponding lenses are configured in the illumination system and the imaging system to achieve imaging of highly transparent embryo samples using Hoffman imaging technology.

[0031] For imaging highly transparent embryo samples in the related art, it is usually necessary to be equipped with a specially designed Hoffman objective lens. All existing Hoffman objective lenses adapted to time-lapse incubators are integrally formed products, which are limited by product specifications, and the imaging resolution and contrast are relatively fixed. For different types and specifications of samples, it is difficult to ensure imaging quality and the adaptability is poor when using fixed-specification Hoffman objective lenses.

[0032] Figure 1 is a schematic structural diagram of a Hoffman imaging system provided by an embodiment of the present utility model; Figure 2 is a schematic diagram of the imaging principle of the relay lens module provided by an embodiment of the present utility model; Figure 3 is a schematic structural diagram of a shaping slit plate provided by an embodiment of the present utility model; Figure 4 is corresponding to the one provided by an embodiment of the present utility model Figure 3 Schematic structural diagram of the objective lens modulation plate. Figure 5 is a schematic structural diagram of another Hoffman imaging system provided by an embodiment of the present utility model; Figure 6 is a schematic structural diagram of another shaping slit plate provided by an embodiment of the present utility model; Figure 7 is corresponding to the one provided by an embodiment of the present utility model Figure 6 Schematic structural diagram of the objective lens modulation plate. As Figures 1 to 4As shown, through practice, the embodiment of the present utility model provides a Hofmann imaging system, including: an illumination module 1, an imaging module 2, and a sample dish 3.

[0033] Among them, the illumination module 1 is arranged above the sample dish 3, and includes an illumination light source 11, a shaping slit plate 13, and a condenser system 12 arranged at intervals in the direction close to the sample dish 3. The illumination light source 11 and the condenser system 12 are arranged at intervals in the direction close to the sample dish 3, and a slit 131 is provided on the shaping slit plate 13.

[0034] The imaging module 2 is arranged below the sample dish 3, and includes an objective lens 21, a relay lens module 22, an objective modulation plate 23, a tube lens 24, and an image collector 25 arranged at intervals in the direction away from the sample dish 3. The objective modulation plate 23 is matched with the slit 131, and the relay lens module 22 is detachably connected to the imaging module 2. The relay lens module 22 includes a first lens 221 and a second lens 222 arranged at intervals along the optical path direction, and the front focal plane of the first lens 221 coincides with the rear focal plane of the objective lens 21.

[0035] In the embodiment of the present utility model, the Hofmann imaging system is arranged in a time-lapse incubator. When microscopic imaging of an embryo sample is required, the staff first loads the sample dish 3 containing the embryo sample into the time-lapse incubator. When the sample dish 3 is installed in place, it is located between the illumination module 1 and the imaging module 2.

[0036] Reference Figures 1 to 4 , when imaging cells with relatively high transparency, the illumination module 1 is started, and the illumination light source 11 emits light. When the light passes through the slit 131 of the shaping slit plate 13, it is blocked to a certain extent, and only part of the light of the illumination spot is allowed to pass through the slit 131. After passing through the condenser system 12, the light is focused on the transparent sample on the sample dish 3, generating refraction and diffraction. After the light passes through the rear focal plane of the objective lens 21, it is secondarily imaged through the first lens 221 and the second lens 222 in the relay lens module 22. The structure of the slit 131 and the objective modulation plate 23 are adjusted to the corresponding optimal imaging position to form a Hofmann imaging structure. Three regions of dark, gray, and bright are formed on the objective modulation plate 23. Finally, refracted and diffracted light at different angles hits different regions of the objective modulation plate 23, so that the transparent sample produces light and dark changes, and the imaging has a relief effect. Finally, it passes through the tube lens 24 and the sample is imaged using the image collector 25. By using the cooperative structure composed of the objective lens 21, the relay lens module 22, and the objective modulation plate 23, the imaging ability of the transparent sample is effectively improved, and the three-dimensional sense and layering of the microscopic imaging are improved.

[0037] By adopting the Hoffmann imaging system provided by the embodiments of the present utility model, a Hoffmann imaging structure is formed by respectively arranging a shaping slit plate 13, a relay lens module 22 behind the objective lens 21, and an objective lens modulation plate 23 in the illumination module 1 and the imaging module 2. Compared with a conventional Hoffmann objective lens, the objective lens 21 and the objective lens modulation plate 23 are respectively arranged outside the relay lens module 22. The relay lens module 22 images the rear focal plane of the objective lens 21, and the objective lens modulation plate 23 images outside the objective lens 21. That is, a Hoffmann objective lens can be replaced by a standard ordinary objective lens plus a relay lens module 22. While ensuring the Hoffmann imaging function, better imaging quality can be achieved by selecting an objective lens with better performance. Further, by separately replacing the corresponding combination of the shaping slit plate 13 and the objective lens modulation plate 23, dynamic regulation of the imaging resolution and imaging contrast of the system can be realized according to different types of actual samples and imaging requirements, without being restricted by the specifications of conventional Hoffmann objective lens products, reducing redundant waste of labor and equipment, and improving adaptability and imaging quality.

[0038] Exemplarily, referring to Figure 2 , in the embodiments of the present utility model, the imaging principle of the relay lens module 22 is as shown in the figure. The imaging object height of the transparent sample behind the objective lens 21 is h1. After secondary imaging by the first lens 221 and the second lens 222 in the relay lens module 22, the imaging image height on the rear focal plane of the relay lens module 22 is h2. The specific corresponding relationship is:

[0039]

[0040] where f1 and f2 are the focal lengths of the first lens 221 and the second lens 222 respectively.

[0041] Exemplarily, in the embodiments of the present utility model, on the basis of the fixed imaging magnification of the objective lens 21, the first lens 221 and the second lens 222 in the relay lens module 22 can be preset or configured separately in a detachable and adjustable form to adjust the imaging image height h2 on the rear focal plane of the relay lens module 22. For example, the magnification of the imaging system can be regulated by adjusting the focal lengths of the first lens 221 and the second lens 222.

[0042] Optionally, the shaping slit plate 13 is movably connected to the illumination module 1 to have a first working position located at the front focal plane of the condenser system 12 and a second working position deviated from the optical path; the relay lens module 22 and the objective modulation plate 23 are jointly movably connected to the imaging module 2 to have a third working position located between the objective 21 and the tube lens 24 and a fourth working position deviated from the optical path. Exemplarily, in the embodiment of the present invention, when imaging conventional biological tissues and cells using this imaging system, the shaping slit plate 13 can be adjusted to the second working position and the relay lens module 22 and the objective modulation plate 23 can be adjusted to the fourth working position manually or by a relevant driving structure, so that the shaping slit plate 13, the relay lens module 22 and the objective modulation plate 23 are all moved away from the light path of the illumination light source 11 and the imaging path of the image collector 25, and the overall is switched to the bright-field illumination mode. At this time, the illumination module 1 is started, and the light emitted by the illumination light source 11 is focused on the sample in the sample dish 3 through the condenser system 12 to achieve bright-field illumination, and the imaging module 2 composed of the objective 21, the tube lens 24 and the image collector 25 below the sample dish 3 is used to image the sample in the sample dish 3.

[0043] Further, when imaging biological tissues and cells with a certain transparency, the shaping slit plate 13 is adjusted to the first working position, and the relay lens module 22 and the objective modulation plate 23 are adjusted to the fourth working position, so that the shaping slit plate 13 is adjusted to the light path of the illumination light source 11. The illumination module 1 is started, and the light emitted by the illumination light source 11 is focused on the sample in the sample dish 3 after passing through the shaping slit plate 13 and the condenser system 12. The light on the shaping slit plate 13 is blocked by the slit 131, and only part of the light of the illumination spot is allowed to pass through the slit 131, and then is focused on the sample in the sample dish 3 through the condenser system 12 to achieve oblique illumination. Finally, the image collector 25 is used to image the sample with high resolution. Compared with the bright-field imaging mode, the collected pictures are more three-dimensional and hierarchical. With this adjustable design, the Hoffman imaging system can be freely switched between multiple imaging modes, reducing the redundancy of microscopic imaging equipment and further improving the adaptability and practicality.

[0044] Optionally, the light-transmitting aperture of the slit 131 is adjustable. Within a certain range, the larger the illumination angle of the spot formed by oblique illumination imaging on the sample in the sample dish 3, the stronger the imaging resolution. Exemplarily, in the embodiment of the present invention, multiple shaping slit plates 13 with slits 131 of different length and width size specifications can be prepared in advance. According to different types of samples and imaging requirements, different size specifications of slits 131 can be used for adjustment of the oblique illumination angle by replacement, further expanding the dynamic regulation range of imaging contrast and resolution.

[0045] Exemplarily, the shaping slit plate 13 can also be configured to be horizontally position-adjustable. Through external manual adjustment or a corresponding driving mechanism, the shaping slit plate 13 located at the first working position is moved left and right horizontally, so as to adjust the relative position of the light-passing area of the slit 131 with respect to the area irradiated by the light irradiated on the shaping slit plate 13. For example, referring to Figure 3 , while keeping the width L and length h of the light-passing area of the slit 131 unchanged, increasing the distance d between the center of the light-passing area and the center of the shaping slit plate 13 can increase the oblique illumination angle, thereby improving the imaging resolution and the three-dimensional sense when imaging a transparent sample within a certain range. Referring to Figure 4 The objective modulation plate 23 is located at the rear focal plane of the objective 21 and is in an optically conjugate state with the slit 131. The modulation plate 23 is also divided into three regions A, B, and C, and there are differences in the light transmittance of the three regions. The specific difference values need to be determined according to the design specifications of the system. Region A is generally set to a light transmittance of 0%, region B is generally set to a light transmittance of 10% - 50%, and region C is generally set to a light transmittance of 100%.

[0046] Optionally, a polarizer 14 is provided between the illumination light source 11 and the shaping slit plate 13, and an analyzer 15 matching the polarizer 14 is provided at the slit 131 of the shaping slit plate 13. Exemplarily, in the embodiment of the present invention, referring to Figure 5 , in another possible implementation manner, the polarization modulation of the light beam can also be achieved by providing a polarizer 14 between the illumination light source 11 and the shaping slit plate 13 and providing an analyzer 15 at the slit 131 of the shaping slit plate 13. For example, in the light-passing position between the illumination light source 11 and the shaping slit plate 13 located at the first working position, and in the form of providing corresponding polarizing sheets or linear polarizing films at the slit 131, the contrast and the overall light flux are controlled by modulating the polarization.

[0047] Optionally, the polarizer 14 and the analyzer 15 are in sheet form, and the relative angle between the polarizer 14 and the shaping slit plate 13 is adjustable. Exemplarily, referring to Figure 3 and Figure 4 , the light-passing area of the slit 131 can be divided into region A covered by the analyzer 15 and region B through which light can pass. When the distance d between the center of the light-passing area and the center of the shaping slit plate 13 is a fixed value, by rotating the polarizer 14 to reduce the light flux in region A, during the rotation of the polarizer 14, the light transmittance of region A will linearly change between 0% - 100%. The smaller the light flux in region A, the higher the imaging contrast and the stronger the three-dimensional sense of the image, but at the same time, the light flux of the image will also be lower. The length h of the slit 131 is generally determined according to the design requirements. The larger h is, the greater the light flux when the illumination spot reaches the sample surface.

[0048] Optionally, the slit 131 is annular, the analyzer 15 is circular and coaxially covers the slit 131, and the diameter of the analyzer 15 is greater than the inner diameter of the slit 131 and less than the outer diameter of the slit 131. Exemplarily, in another embodiment of the present invention, by improving the form of the slit 131 on the shaping slit plate 13, it is set as an annular slit. Refer to Figure 6 , the annular slit 131 is divided into three regions A, B, and C. Among them, region A is a region with a transmittance of 0%, that is, a light-impermeable region, region B is the region covered by the analyzer 15, and by adjusting the angle between the analyzer 15 and the polarizer 14, dynamic regulation of the light beam transmittance can be achieved, thereby dynamically adjusting the contrast of the image. Region C is a region with a transmittance of 100%, that is, the light completely passes through. The widths and positions of the three regions A, B, and C can all be adjusted according to the design of the system. The wider the width of region C, the greater the light flux of the incident light, but it will cause a decrease in resolution. The position where region C intersects with region B is farther away from the telecentric point, the higher the resolution of the image, but the effective light flux will be less. The above parameters need to be flexibly adjusted according to the system. Refer to Figure 7 , the objective modulation plate 23 is located at the rear focal plane of the objective 21 and is in an optically conjugate state with the slit 131. The modulation plate 23 is also divided into three regions A, B, and C, and there are differences in the light transmittance of the three regions. The specific difference values need to be determined according to the design indicators of the system. Region A is generally set to have a transmittance of 0%, region B is generally set to have a transmittance of 10% - 50%, and region C is generally set to have a transmittance of 100%; by using the annular slit 131 and the modulation plate 23 in combination, the resolution and contrast of the Hoffman imaging system can be effectively improved, and at the same time, the problem of one side of the image being too bright and the other side being too dark during the imaging of the Hoffman system can be effectively solved, further improving the imaging quality. Moreover, through the annular slit 131 structure, oblique illumination imaging forms such as Figure 5 can be realized at multiple angles. Compared with the traditional Hoffman objective lens that can only achieve oblique illumination at a single angle, it can provide higher imaging resolution.

[0049] Optionally, the illumination light source 11 is a light-emitting diode illumination light source, and the wavelength range of the illumination light source 11 is 400 to 700 nm. Exemplarily, in the embodiment of the present invention, the illumination light source 11 uses an LED lamp illumination light source with a wavelength range of 400 to 700 nm. The illumination method can adopt critical illumination or Köhler illumination. Köhler illumination has good illumination uniformity and is suitable for applications that require high precision and high resolution, while critical illumination has a simple structure and is more suitable for inspecting the surface quality and defects of samples. The present invention does not specifically limit the illumination form.

[0050] Optionally, the image collector 25 is a charge-coupled device camera or a complementary metal oxide semiconductor camera. Exemplarily, in the embodiment of the present invention, the image collector 25 may adopt a CCD (Charge coupled Device) camera or a CMOS (Complementary Metal Oxide Semiconductor) camera as the imaging device.

[0051] The embodiment of the present invention also provides a time-lapse incubator, including the Figures 1 to 7 Hoffmann imaging system as shown.

[0052] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings as understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the specification and claims of the patent application of the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, the terms such as "a" or "one" do not denote a quantity limitation, but mean that there is at least one. The terms such as "comprising" or "including" mean that the elements or objects appearing before "comprising" or "including" cover the elements or objects listed after "comprising" or "including" and their equivalents, and do not exclude other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to indicate relative position relationships, and when the absolute position of the object being described changes, the relative position relationships may also change accordingly.

[0053] The above are only optional embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A Huffman imaging system, characterized in that, Comprising: A lighting module (1), an imaging module (2), and a sample dish (3), The lighting module (1) is disposed above the sample dish (3), and includes a lighting light source (11), a shaping slit plate (13), and a condenser system (12) arranged at intervals along the direction close to the sample dish (3). The lighting light source (11) and the condenser system (12) are arranged at intervals along the direction close to the sample dish (3). A slit (131) is provided on the shaping slit plate (13); The imaging module (2) is disposed below the sample dish (3), and includes an objective lens (21), a relay lens module (22), an objective modulation plate (23), a tube lens (24), and an image collector (25) arranged at intervals along the direction away from the sample dish (3). The objective modulation plate (23) matches the slit (131). The relay lens module (22) is detachably connected to the imaging module (2). The relay lens module (22) includes a first lens (221) and a second lens (222) arranged at intervals along the optical path direction. The front focal plane of the first lens (221) coincides with the rear focal plane of the objective lens (21).

2. The Hofmann imaging system according to claim 1, wherein, The shaping slit plate (13) is movably connected to the lighting module (1) to have a first working position located at the front focal plane of the condenser system (12) and a second working position away from the optical path; the relay lens module (22) and the objective modulation plate (23) are jointly movably connected to the imaging module (2) to have a third working position located between the objective lens (21) and the tube lens (24) and a fourth working position away from the optical path.

3. The Hofmann imaging system according to claim 2, wherein The light passing aperture of the slit (131) is adjustable.

4. The Hofmann imaging system according to claim 3, characterized in that, A polarizer (14) is provided between the lighting light source (11) and the shaping slit plate (13), and an analyzer (15) matching the polarizer (14) is provided at the slit (131) of the shaping slit plate (13).

5. The Hofmann imaging system according to claim 4, characterized in that, The polarizer (14) and the analyzer (15) are in sheet form, and the relative angle between the polarizer (14) and the shaping slit plate (13) is adjustable.

6. The Hofmann imaging system according to claim 5, wherein The slit (131) is in a ring shape, the analyzer (15) is in a circular shape and coaxially covers the slit (131). The diameter of the analyzer (15) is greater than the inner diameter of the slit (131) and less than the outer diameter of the slit (131).

7. The Hofmann imaging system according to any one of claims 1 to 6, characterized in that, The lighting light source (11) is a light emitting diode lighting source, and the wavelength range of the lighting light source (11) is 400 to 700 nm.

8. The Hofmann imaging system according to any one of claims 1 to 6, characterized in that, The image collector (25) is a charge coupled device camera or a complementary metal oxide semiconductor camera.

9. A time-lapse incubator, characterized in that, Including the Hofmann imaging system according to any one of claims 1 to 6.

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