Optical system for detecting circulating tumor cells

Abstract

The invention discloses an optical system for circulating tumor cell detection, which comprises a sample table for placing a sample, an objective lens imaging system, an image receiving system and an illuminating system which are sequentially arranged from front to back, the device is characterized in that the illumination system comprises a transmission illumination system arranged in front of the sample table and a fluorescent illumination system arranged behind the objective lens imaging system, and light emitted by the transmission illumination system enters the image receiving system through the sample and the objective lens imaging system; an excitation light beam emitted by the fluorescence illumination system is incident on a sample through the objective lens imaging system to excite fluorescence, and the fluorescence is incident on the image receiving system through the objective lens imaging system. And fluorescence illumination can be used for analyzing a sample with a fluorescence label, and a tiny or complex structure in the sample can be identified, so that the early detection sensitivity and specificity of diseases such as cancers and the like can be improved.

Description

Technical Field

[0001] The invention relates to an optical system, and in particular to an optical system for detecting circulating tumor cells. Background Art

[0002] Circulating tumor cells (CTCs) refer to tumor cells that have shed from primary tumors or metastatic lesions and entered the blood circulation system. Since CTCs can spread through the blood to other parts of the body to form new metastatic lesions, their number and characteristics can reflect the biological behavior and treatment response of the tumor. Therefore, CTCs are of great value in cancer diagnosis, prognosis assessment, and efficacy monitoring.

[0003] With the development of science and technology, methods for detecting CTCs have emerged one after another. When observing traditionally stained CTC slices, the sample is illuminated by the uniform illumination light provided by transmitted illumination, and the morphological and appearance information of CTC can be obtained by collecting the transmitted illumination light signal; when observing CTC slices with special fluorescent markers, the information of specific markers in the CTC slices cannot be obtained using transmitted illumination, so fluorescent illumination is required. Fluorescent illumination refers to the use of excitation light of a specific wavelength to illuminate the CTC slice. The excitation light can excite the fluorescent dye in the CTC slice. The fluorescent dye will produce fluorescence after being excited by the excitation light. Collecting the fluorescent signal can obtain the fluorescent image of CTC. Therefore, how to make full use of the advantages of transmitted illumination and fluorescent illumination to design an optical system to detect CTC has become a new development direction for technological innovation.

[0004] Existing optical systems for circulating tumor cell detection usually choose a single illumination mode among transmission illumination, dark field illumination or fluorescence illumination. Although images of CTC slices can be obtained, the functions are relatively simple. The Chinese invention patent application with application number 202311580141.0 provides a design method for a multi-channel fluorescence slice scanner, which can generate fluorescence of a specific wavelength under the excitation of different excitation light sources and obtain corresponding fluorescence images, but the detection method is still relatively simple. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an optical system for circulating tumor cell detection that reasonably combines transmitted illumination and fluorescent illumination, which can use transmitted illumination to analyze traditionally stained samples and use fluorescent illumination to analyze fluorescently labeled samples.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: an optical system for circulating tumor cell detection, including a sample stage for placing samples, an objective imaging system, an image receiving system and an illumination system arranged in sequence from front to back, the illumination system including a transmission illumination system arranged in front of the sample stage and a fluorescence illumination system arranged behind the objective imaging system, the light emitted by the transmission illumination system passes through the sample and the objective imaging system and is incident on the image receiving system, the excitation light beam emitted by the fluorescence illumination system passes through the objective imaging system and is incident on the sample to excite fluorescence, and the fluorescence passes through the objective imaging system and is incident on the image receiving system.

[0007] Compared with the prior art, the advantage of the present invention is that the illumination system of the entire optical system is composed of a transmission illumination system arranged in front of the sample stage and a fluorescence illumination system arranged behind the objective lens imaging system, and the light emitted by the transmission illumination system is incident on the image receiving system through the sample and the objective lens imaging system, while the excitation light beam emitted by the fluorescence illumination system is incident on the sample through the objective lens imaging system to excite fluorescence, and the fluorescence is incident on the image receiving system through the objective lens imaging system. The two illumination modes can be easily switched, and both transmission illumination can be used to analyze traditional stained samples and fluorescence illumination can be used to analyze samples with fluorescent labels. At the same time, transmission illumination and fluorescence illumination conditions are available, and high-resolution digital images can be generated, and tiny or complex structures in the sample can be identified, so as to improve the sensitivity and specificity of early detection of diseases such as cancer.

[0008] Preferably, the fluorescent illumination system comprises a fluorescent illumination module capable of emitting excitation light beams of multiple bands, a collimating lens group and a plurality of light separation modules matching the bands of the excitation light beams, the collimating lens group collimates the excitation light beam emitted by the fluorescent illumination module into a parallel excitation light beam, the light separation module is arranged on a separation module converter, the separation module converter is used to switch the light separation module into the optical path, the light separation module is used to reflect the parallel excitation light beams into the objective imaging system, and allow the light emitted by the objective imaging system to be transmitted into the image receiving system.

[0009] Preferably, the light separation module is composed of an excitation plate, a dichroic mirror and a cutoff plate, wherein the excitation plate is used to allow an excitation light beam of a specific wavelength band to pass through, the dichroic mirror is used to reflect the parallel excitation light beam into the objective imaging system, and allow the light emitted by the objective imaging system to be transmitted into the image receiving system, and the cutoff plate is used to filter the reflected or scattered excitation light beam, and allow the fluorescence generated by the sample to pass through. The excitation plate can filter out unnecessary wavelengths, selectively allow an excitation light beam of a specific wavelength band to pass through, and ensure that the sample receives an excitation light beam of a specific wavelength, thereby improving the specificity and contrast of imaging. The cutoff plate can filter out the excitation light beam reflected or scattered on the cutoff plate, and ensure that the image receiving system only receives the fluorescence generated by the sample, thereby improving the clarity and contrast of the image.

[0010] Preferably, the fluorescent lighting module is composed of a first LED light source, a second LED light source, a third LED light source and a fourth LED light source of different wavelength bands and a first dichroic mirror, a second dichroic mirror and a third dichroic mirror arranged in sequence along the optical path, wherein the first LED light source is arranged on one side of the first dichroic mirror, the second LED light source is arranged on one side of the second dichroic mirror, the third LED light source is arranged on one side of the third dichroic mirror, and the fourth LED light source is arranged on the rear side of the third dichroic mirror, the first dichroic mirror allows the excitation light beam emitted by the first LED light source to be reflected and allows the excitation light beam emitted by the second LED light source, the third LED light source and the fourth LED light source to be transmitted, the second dichroic mirror allows the excitation light beam emitted by the second LED light source to be reflected and allows the excitation light beam emitted by the third LED light source and the fourth LED light source to be transmitted, and the third dichroic mirror allows the excitation light beam emitted by the third LED light source to be reflected and allows the excitation light beam emitted by the fourth LED light source to be transmitted. By setting LED light sources of multiple wavelength bands, the types of fluorescent dyes used can be expanded to achieve multi-band detection.

[0011] Preferably, the separation module converter is provided with four light separation modules, which are respectively a first light separation module matching the wavelength of the excitation light beam emitted by the first LED light source, a second light separation module matching the wavelength of the excitation light beam emitted by the second LED light source, a third light separation module matching the wavelength of the excitation light beam emitted by the third LED light source, and a fourth light separation module matching the wavelength of the excitation light beam emitted by the fourth LED light source. Multiple fluorescence band illumination is achieved through one-to-one matching between the fluorescence illumination module and the light separation module, thereby expanding the types of fluorescent dyes used and realizing multi-band detection; that is, the dichroic mirror is used to separate the excitation light beam and the fluorescence, the excitation light beam is reflected by the dichroic mirror onto the sample to excite the fluorescence, and the fluorescence is transmitted through the subsequent optical system for detection, thereby obtaining a high-resolution image and minimizing the background noise.

[0012] Preferably, an electric shutter is provided between the sample stage and the transmission illumination system, and when the transmission illumination mode is used, the electric shutter is opened, and when the fluorescence illumination mode is used, the electric shutter is closed. This structure can prevent the excitation light beam emitted by the fluorescence illumination system from damaging the transmission illumination system.

[0013] Preferably, the objective lens imaging system includes an objective lens converter, on which at least one low-power objective lens and at least one high-power objective lens are arranged, and the low-power objective lens or the high-power objective lens is switched into the light path through the objective lens converter. In the transmission illumination mode and the fluorescence illumination mode, it is necessary to first confirm the approximate position of the sample using the illumination light in the low-power mode, and fine-tune the relative distance between the objective lens and the sample until the image of the sample is clearly seen; then use the objective lens converter to switch the high-power objective lens, and perform image acquisition in the transmission illumination mode and the fluorescence illumination mode. The present structure can conveniently switch between the two objective lenses.

[0014] The low-power objective lens may be a 2x objective lens, and the high-power objective lens may be a 40x objective lens.

[0015] Preferably, the wavelength band of the excitation beam of the first LED light source is 330nm-385nm, the wavelength band of the excitation beam of the second LED light source is 460nm-495nm, the wavelength band of the excitation beam of the third LED light source is 510nm-550nm, and the wavelength band of the excitation beam of the fourth LED light source is 620nm-650nm.

[0016] The optical system of the present invention can also be used in the field of pathology, especially in application scenarios that require high-precision imaging. The lens is required to capture tiny structures, and it is necessary to ensure that the optical system can distinguish extremely small points or line pairs in the details of the object to achieve high-definition imaging. For example, in the process of detecting sperm motility, the optical system of the present invention can be used to obtain information such as the number and morphology of sperm; for another example, in the process of breast cancer screening, the optical system of the present invention can be used to detect the expression of estrogen receptors and progesterone receptors in breast cancer cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an embodiment of the present invention; Figure 2 This is an optical principle diagram of Example 1 of the embodiment of the present invention; Figure 3 This is an optical principle diagram of Example 2 of the embodiment of the present invention; Figure 4 This is an optical principle diagram of Example 3 of the embodiment of the present invention; Figure 5 This is an optical principle diagram of Example 4 of the embodiment of the present invention; Figure 6 This is an optical principle diagram of Example 5 of Embodiment 1 of the present invention.

[0018] Description of reference numerals: 1. Sample stage; 2. Objective imaging system; 3. Image receiving system; 4. Transmitted illumination system; 41. Transmitted illumination light source; 42. Transmitted illumination collimator group; 5. Fluorescent illumination system; 51, fluorescent lighting module; 511, first LED light source; 512, second LED light source; 513, third LED light source; 514, fourth LED light source; 515, first dichroic mirror; 516, second dichroic mirror; 517, third dichroic mirror; 52. Light separation module; 52-1. First light separation module; 521-1. First excitation plate; 522-1. First dichroic mirror; 523-1. First cut-off plate; 52-2. Second light separation module; 521-2. Second excitation plate; 522-2. Second dichroic mirror; 523-2. Second cut-off plate; 52-3. Third light separation module; 521-3. Third excitation plate; 522-3. Third dichroic mirror; 523-3. Third cut-off plate; 52-4. Fourth light separation module; 521-4. Fourth excitation plate; 522-4. Fourth dichroic mirror; 523-4. Fourth cut-off plate; 53. Collimating lens group; 6. Electric shutter. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below with reference to the accompanying drawings.

[0020] Example: Figure 1 As shown, an optical system for circulating tumor cell detection includes a sample stage 1 for placing samples, an objective lens imaging system 2, an image receiving system 3, a transmission illumination system 4, a fluorescence illumination system 5 and an electric shutter 6. The transmission illumination system 4 is arranged in front of the sample stage 1. The transmission illumination system 4 includes a transmission illumination light source 41 and a transmission illumination collimating lens group 42. The fluorescence illumination system 5 includes a fluorescence illumination module 51, a collimating lens group 53 and a plurality of light separation modules 52. The light separation module 52 is arranged on a separation module converter behind the objective lens imaging system 2. The collimating lens group 53 and the fluorescence illumination module 51 are arranged on the side of the light separation module 52. The separation module converter is a prior art, and its function is to switch the corresponding light separation module 52 into the optical path. In this embodiment, there are four light separation modules 52, which are respectively Figure 2 and Figure 3 The first light separation module 52-1 shown, Figure 4 The second light separation module 52-2 shown, Figure 5 The third light separation module 52-3 and Figure 6 The fourth light separation module 52 - 4 is shown.

[0021] The light emitted by the transmitted illumination system 4 passes through the transmitted illumination collimating lens group 42, the sample on the sample stage 1 and the objective imaging system 2, and is incident on the image receiving system 3 through the first light separation module 52-1. The excitation light beam emitted by the fluorescent illumination module 51 is collimated into a parallel excitation light beam by the collimating lens group 53, passes through the first light separation module 52-1 or the second light separation module 52-2 or the third light separation module 52-3 or the fourth light separation module 52-4, and the objective imaging system 2, and is incident on the sample on the sample stage 1 to excite fluorescence. The fluorescence passes through the objective imaging system 2 and the corresponding light separation module and is incident on the image receiving system 3.

[0022] In order to prevent the excitation light beam emitted by the fluorescent illumination system 5 from damaging the transmission illumination system 4, an electric shutter 6 is arranged between the sample stage 1 and the transmission illumination system 4. When the transmission illumination mode is used, the electric shutter 6 is opened; when the fluorescent illumination mode is used, the electric shutter 6 is closed.

[0023] The fluorescent lighting module 51 can emit excitation light of multiple wavelength bands. In this embodiment, the fluorescent lighting module 51 is composed of a first LED light source 511 of 330nm-385nm wavelength band, a second LED light source 512 of 460nm-495nm wavelength band, a third LED light source 513 of 510nm-550nm wavelength band, a fourth LED light source 514 of 620nm-650nm wavelength band, a first dichroic mirror 515, a second dichroic mirror 516 and a third dichroic mirror 517. The first LED light source 511 is arranged on one side of the first dichroic mirror 515, the second LED light source 512 is arranged on one side of the second dichroic mirror 516, and the third LED light source 513 is arranged on the other side of the third dichroic mirror 517. On one side, the fourth LED light source 514 is arranged on the rear side of the third dichroic mirror 517, the first dichroic mirror 515 allows the excitation beam emitted by the first LED light source 511 to be reflected and allows the excitation beams emitted by the second LED light source 512, the third LED light source 513 and the fourth LED light source 514 to be transmitted, the second dichroic mirror 516 allows the excitation beam emitted by the second LED light source 512 to be reflected and allows the excitation beams emitted by the third LED light source 513 and the fourth LED light source 514 to be transmitted, and the third dichroic mirror 517 allows the excitation beam emitted by the third LED light source 513 to be reflected and allows the excitation beam emitted by the fourth LED light source 514 to be transmitted.

[0024] like Figure 2 and Figure 3 As shown, the first light separation module 52-1 is composed of a first excitation plate 521-1, a first dichroic mirror 522-1 and a first cut-off plate 523-1. Figure 4 As shown, the second light separation module 52-2 is composed of a second excitation plate 521-2, a second dichroic mirror 522-2 and a second cut-off plate 523-2. Figure 5 As shown, the third light separation module 52-3 is composed of a third excitation plate 521-3, a third dichroic mirror 522-3 and a third cut-off plate 523-3. Figure 6 As shown, the fourth light separation module 52 - 4 is composed of a fourth excitation plate 521 - 4 , a fourth dichroic mirror 522 - 4 and a fourth cut-off plate 523 - 4 .

[0025] The excitation light beam emitted by the first LED light source 511 is incident on the collimating lens group 53 after being reflected by the first dichroic mirror 515, and then is reflected by the first dichroic mirror 522-1 to the sample on the sample stage 1 to excite fluorescence. The fluorescence is transmitted through the first dichroic mirror 522-1 and then is incident on the image receiving system 3 through the first cut-off plate 523-1; the excitation light beam emitted by the second LED light source 512 is reflected by the second dichroic mirror 516 and then is transmitted through the first dichroic mirror 515, and then is incident on the collimating lens group 53; the excitation light beam emitted by the second LED light source 512 is reflected by the second dichroic mirror 516 and then is transmitted through the first dichroic mirror 515, and then is incident on the collimating lens group 53; the excitation light beam emitted by the second LED light source 512 is reflected by the second dichroic mirror 522-2 after being reflected by the second excitation light plate 521-2 to the sample on the sample stage 1 to excite fluorescence. The fluorescence is transmitted through the second dichroic mirror 522-2 and then is incident on the image receiving system 3 through the second cut-off plate 523-2; The excitation light beam is reflected by the third dichroic mirror 517 and then transmitted through the second dichroic mirror 516 and the first dichroic mirror 515 to enter the collimating lens group 53. After passing through the third excitation plate 521-3, it is reflected by the third dichroic mirror 522-3 to the sample on the sample stage 1 to excite fluorescence. The fluorescence is transmitted through the third dichroic mirror 522-3 and then transmitted through the third cut-off plate 523-3 to enter the image receiving system 3; the excitation light beam emitted by the fourth LED light source 514 is transmitted through the third dichroic mirror 517, the second dichroic mirror 516 and the first dichroic mirror 515 to enter the collimating lens group 53. After passing through the fourth excitation plate 521-4, it is reflected by the fourth dichroic mirror 522-4 to the sample on the sample stage 1 to excite fluorescence. The fluorescence is transmitted through the fourth dichroic mirror 522-4 and then transmitted through the fourth cut-off plate 523-4 to enter the image receiving system 3.

[0026] When using the transmitted illumination and fluorescent illumination modes, it is usually necessary to first confirm the approximate position of the sample using the illumination light in the low-magnification mode, and fine-tune the relative distance between the objective lens and the sample until the image of the sample is clearly seen; then use the high-magnification objective lens to capture the image. The objective lens imaging system 2 can be composed of an objective lens converter and a low-magnification objective lens and a high-magnification objective lens arranged on the objective lens converter, such as a 2x objective lens and a 40x objective lens. The low-magnification objective lens or the high-magnification objective lens can be easily switched into the light path through the objective lens converter.

[0027] The optical principle of the optical system of the present invention is described below with reference to several specific examples in conjunction with the accompanying drawings.

[0028] Example 1: like Figure 2As shown, at this time, the system is in the transmission illumination mode, the electric shutter 6 is in the open state, the fluorescent illumination system 5 does not emit light, only the transmission illumination system 4 emits light, and the separation module converter switches the first light separation module 52-1 into the light path. The light emitted by the transmission illumination light source 41 is collimated by the transmission illumination collimator lens group 42 to form parallel light and irradiate the sample on the sample stage 1. The parallel light transmitted by the sample passes through the objective lens imaging system 2, the first dichroic mirror 522-1, and the first cutoff plate 523-1 and is incident on the image receiving system 3.

[0029] Example 2: like Figure 3 As shown, at this time, the system is in the fluorescent illumination mode, and the electric shutter 6 is in the closed state. At this time, only the first LED light source 511 in the 330nm-385nm band emits light, and the separation module converter switches the first light separation module 52-1 into the optical path. The excitation light beam emitted by the first LED light source 511 is reflected by the first dichroic mirror 515 and then incident on the collimating lens group 53. The collimating lens group 53 collimates it into a parallel excitation light beam, passes through the first excitation plate 521-1, is reflected by the first dichroic mirror 522-1, passes through the objective imaging system 2, and is incident on the sample on the sample stage 1 to excite fluorescence. The fluorescence passes through the objective imaging system 2, the first dichroic mirror 522-1 and the first cut-off plate 523-1 and is incident on the image receiving system 3.

[0030] Example 3: like Figure 4 As shown, at this time, the system is in the fluorescent illumination mode, and the electric shutter 6 is in the closed state. At this time, only the second LED light source 512 in the 460nm-495nm band emits light, and the separation module converter switches the second light separation module 52-2 into the optical path. The excitation light beam emitted by the second LED light source 512 is reflected by the second dichroic mirror 516, transmitted through the first dichroic mirror 515 and incident on the collimating lens group 53, and is collimated by the collimating lens group 53 into a parallel excitation light beam, which is reflected by the second excitation plate 521-2 and the second dichroic mirror 522-2, and is incident on the sample on the sample stage 1 through the objective imaging system 2 to excite fluorescence, and the fluorescence is incident on the image receiving system 3 through the objective imaging system 2, the second dichroic mirror 522-2 and the second cut-off plate 523-2.

[0031] Example 4: like Figure 5As shown, at this time, the system is in the fluorescent illumination mode, the electric shutter 6 is in the closed state, and at this time, only the third LED light source 513 in the 510nm-550nm band emits light, and the separation module converter switches the third light separation module 52-3 into the optical path. The excitation light beam emitted by the third LED light source 513 is reflected by the third dichroic mirror 517, transmitted through the second dichroic mirror 516 and the first dichroic mirror 515, and is incident on the collimating lens group 53, collimated by the collimating lens group 53 into a parallel excitation light beam, and after passing through the third excitation plate 521-3, it is reflected by the third dichroic mirror 522-3, and is incident on the sample on the sample stage 1 through the objective lens imaging system 2 to excite fluorescence, and the fluorescence is incident on the image receiving system 3 through the objective lens imaging system 2, the third dichroic mirror 522-3 and the third cut-off plate 523-3.

[0032] Example 5: like Figure 6 As shown, at this time, the system is in the fluorescent illumination mode, the electric shutter 6 is in the closed state, and at this time, only the fourth LED light source 514 in the 620nm-650nm band emits light, and the separation module converter switches the fourth light separation module 52-4 into the optical path. The excitation light beam emitted by the fourth LED light source 514 is transmitted through the third dichroic mirror 517, the second dichroic mirror 516 and the first dichroic mirror 515, and then enters the collimating lens group 53, and is collimated by the collimating lens group 53 into a parallel excitation light beam, and then passes through the fourth excitation plate 521-4 and is reflected by the fourth dichroic mirror 522-4, and then passes through the objective lens imaging system 2 and enters the sample on the sample stage 1 to excite fluorescence, and the fluorescence passes through the objective lens imaging system 2, the fourth dichroic mirror 522-4 and the fourth cut-off plate 523-4 and enters the image receiving system 3.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit it. Although this patent belongs to the field of optical system technology, it can also be used for industrial algae detection, microbial observation, etc. on the basis of this patent. Although the present invention is described in detail according to the embodiments, a person of ordinary skill in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be covered by the protection scope of the claims of the present invention.

Claims

1. An optical system for detecting circulating tumor cells, comprising a sample stage for placing a sample, an objective lens imaging system, an image receiving system and an illumination system arranged in sequence, characterized in that: The illumination system comprises a transmission illumination system arranged in front of the sample stage and a fluorescence illumination system arranged behind the objective lens imaging system. The light emitted by the transmission illumination system passes through the sample and the objective lens imaging system and is incident on the image receiving system. The excitation light beam emitted by the fluorescence illumination system passes through the objective lens imaging system and is incident on the sample to excite fluorescence. The fluorescence passes through the objective lens imaging system and is incident on the image receiving system.

2. An optical system for detecting circulating tumor cells according to claim 1, characterized in that: The fluorescent illumination system comprises a fluorescent illumination module capable of emitting excitation light beams of multiple wavelength bands, a collimating lens group and a plurality of light separation modules matching the wavelength bands of the excitation light beams. The collimating lens group collimates the excitation light beam emitted by the fluorescent illumination module into a parallel excitation light beam. The light separation module is arranged on a separation module converter. The separation module converter is used to switch the light separation module into an optical path. The light separation module is used to reflect the parallel excitation light beams into the objective lens imaging system and allow the light emitted by the objective lens imaging system to be transmitted into the image receiving system.

3. An optical system for detecting circulating tumor cells according to claim 2, characterized in that: The light separation module is composed of an excitation plate, a dichroic mirror and a cutoff plate. The excitation plate is used to allow an excitation light beam of a specific wavelength band to pass through. The dichroic mirror is used to reflect the parallel excitation light beam into the objective imaging system and allow the light emitted by the objective imaging system to be transmitted into the image receiving system. The cutoff plate is used to filter the reflected or scattered excitation light and allow the fluorescence generated by the sample to pass through.

4. An optical system for detecting circulating tumor cells according to claim 3, characterized in that: The fluorescent lighting module is composed of a first LED light source, a second LED light source, a third LED light source and a fourth LED light source of different wavelength bands and a first dichroic mirror, a second dichroic mirror and a third dichroic mirror which are arranged in sequence. The first LED light source is arranged on one side of the first dichroic mirror, the second LED light source is arranged on one side of the second dichroic mirror, the third LED light source is arranged on one side of the third dichroic mirror, and the fourth LED light source is arranged on the rear side of the third dichroic mirror. The first dichroic mirror allows the excitation light beam emitted by the first LED light source to be reflected while allowing the excitation light beam emitted by the second LED light source, the third LED light source and the fourth LED light source to be transmitted. The second dichroic mirror allows the excitation light beam emitted by the second LED light source to be reflected while allowing the excitation light beam emitted by the third LED light source and the fourth LED light source to be transmitted. The third dichroic mirror allows the excitation light beam emitted by the third LED light source to be reflected while allowing the excitation light beam emitted by the fourth LED light source to be transmitted.

5. An optical system for detecting circulating tumor cells according to claim 4, characterized in that: Four light separation modules are arranged on the separation module converter, which are respectively a first light separation module matching the wavelength band of the excitation light beam emitted by the first LED light source, a second light separation module matching the wavelength band of the excitation light beam emitted by the second LED light source, a third light separation module matching the wavelength band of the excitation light beam emitted by the third LED light source, and a fourth light separation module matching the wavelength band of the excitation light beam emitted by the fourth LED light source.

6. An optical system for detecting circulating tumor cells according to any one of claims 1 to 5, characterized in that: An electric shutter is arranged between the sample stage and the transmission illumination system. When the transmission illumination mode is used, the electric shutter is opened, and when the fluorescence illumination mode is used, the electric shutter is closed.

7. An optical system for detecting circulating tumor cells according to claim 6, characterized in that: The objective lens imaging system comprises an objective lens converter, on which at least one low-power objective lens and at least one high-power objective lens are arranged, and the low-power objective lens or the high-power objective lens is switched into the optical path through the objective lens converter.

8. An optical system for detecting circulating tumor cells according to claim 7, characterized in that: The low-power objective lens is a 2-power objective lens.

9. An optical system for detecting circulating tumor cells according to claim 7, characterized in that: The high-power objective lens is a 40-times objective lens.

10. An optical system for detecting circulating tumor cells according to claim 4, characterized in that: The wavelength band of the excitation beam of the first LED light source is 330nm-385nm, the wavelength band of the excitation beam of the second LED light source is 460nm-495nm, the wavelength band of the excitation beam of the third LED light source is 510nm-550nm, and the wavelength band of the excitation beam of the fourth LED light source is 620nm-650nm.

Images