Multi-mark endoscopic imaging lens for digestive tract

Abstract

The invention discloses a multi-label endoscopic imaging lens for a digestive tract, and belongs to the field of biomedical microscopic endoscopic images. The endoscopic imaging lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The first lens focuses laser, and the second lens is matched with the first lens to limit a light beam in an effective clear aperture of the lens; the third lens corrects chromatic aberration; a fourth lens and a fifth lens are combined to correct aberration; the sixth lens is an aspheric lens and corrects spherical aberration brought in collimation and focusing systems, and the seventh lens is matched with the sixth lens to correct chromatic aberration. The working spectral range of the microscope objective set is 488-860 nm, the effective clear aperture is smaller than 1.8 mm, the mechanical outer diameter is not larger than 2.6 mm, the numerical aperture at the object space or the tissue is 0.55, the imaging view field is 450 microns, the magnification factor is 2.14 times, and the working distance is 84 microns. And the effect of matching excitation and fluorescence spectrum of a clinically available fluorescence contrast agent is realized.

Description

Technical Field

[0001] The present invention belongs to the field of biomedical microendoscopic imaging, and more specifically, relates to a multi-marked endoscopic imaging lens for the digestive tract. Background Art

[0002] Since entering the field of in vivo imaging, confocal endoscopy has proven its advantages in in situ and real-time examination of living tissues at a microscopic scale. However, current confocal endoscopy mainly relies on a single or limited fluorescence spectral band, and it is difficult to distinguish in vivo tissue information of different structures through a single fluorescence signal.

[0003] In order to simultaneously collect different structural / cellular information labeled with different fluorescent dyes, it is necessary to expand the working band to achieve a wide spectrum covering the visible light to near-infrared region. The ensuing problem is that the aberration correction of the wide-spectrum endoscopic imaging lens is difficult and the miniaturization design is difficult. Summary of the invention

[0004] In view of the defects of the related art, the purpose of the present invention is to provide a multi-labeled endoscopic imaging lens and an endoscopic imaging probe for the digestive tract, aiming to solve the problem that the working band range of the existing endoscopic imaging lens cannot simultaneously match the fluorescence spectrum bands labeled with different fluorescent dyes, resulting in difficulty in distinguishing different structural tissue information in the body.

[0005] To achieve the above-mentioned object, in a first aspect, the present invention provides a multi-marker endoscopic imaging lens for the digestive tract, wherein the endoscopic imaging lens is a microscope objective lens set;

[0006] The microscope objective lens group includes, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens;

[0007] The first lens is in direct contact with the organism to be tested, and is used to focus the laser and collect fluorescence signals at the same time; the second lens, in combination with the first lens, limits the laser beam to the effective aperture; the third lens adopts a double-cemented achromatic lens composed of a negative lens and a positive lens, and is used to correct chromatic aberration; the fourth lens and the fifth lens are respectively positive and negative lenses and are combined with each other to correct aberration; the sixth lens adopts an aspherical lens, and is used to correct the spherical aberration caused by the spherical lens in the collimation and focusing system; the seventh lens adopts a meniscus lens, and is used to correct chromatic aberration to improve imaging quality in combination with the sixth lens.

[0008] Optionally, the working spectrum range of the microscope objective lens group is 488-860nm, the effective aperture is less than 1.8mm, the numerical aperture at the object or tissue is 0.55, the imaging field of view is 450μm, the magnification is 2.14 times, and the working distance is 84μm.

[0009] Optionally, the first lens is made of H-LAF3B material;

[0010] The second lens is made of H-ZK9B material;

[0011] The third lens is made of H-ZF62 material for the lens close to the object plane and H-LAK53 material for the lens close to the image plane;

[0012] The fourth lens is made of H-LAF3B material;

[0013] The fifth lens is made of H-ZF62 material;

[0014] The sixth lens is made of polycarbonate resin EP10000;

[0015] The seventh lens is made of H-ZF62 material.

[0016] Optionally, the first lens is a plano-convex lens with a center thickness of 2.218 mm;

[0017] The second lens is a biconvex lens with a center thickness of 1.216 mm;

[0018] The third lens is a double cemented achromatic lens, the center thickness of the lens close to the object plane is 1.155 mm, and the center thickness of the lens close to the image plane is 0.783 mm;

[0019] The fourth lens is a plano-convex lens with a center thickness of 0.692 mm;

[0020] The fifth lens is a convex lens with a center thickness of 3.000 mm;

[0021] The sixth lens is an aspherical lens with a center thickness of 0.343 mm;

[0022] The seventh lens is a convex lens with a center thickness of 0.927 mm.

[0023] Optionally, the center distance between two adjacent surfaces of the first lens and the second lens is 0.100 mm;

[0024] The center distance between two adjacent surfaces of the second lens and the third lens is 0.100 mm;

[0025] The center distance between two adjacent surfaces of the third lens and the fourth lens is 0.100 mm;

[0026] The center distance between two adjacent surfaces of the fourth lens and the fifth lens is 0.219 mm;

[0027] The center distance between two adjacent surfaces of the fifth lens and the sixth lens is 0.100 mm;

[0028] The center distance between two adjacent surfaces of the sixth lens and the seventh lens is 0.283 mm;

[0029] The center distance between the seventh lens and two adjacent surfaces of the optical fiber bundle is 0.360 mm.

[0030] Optionally, the clear aperture of the mirror surface of the first lens close to the object plane is 0.514 mm; the curvature radius of the mirror surface of the first lens close to the image plane is -1.557 mm, and the clear aperture is 1.741 mm;

[0031] The curvature radius of the mirror surface of the second lens close to the object plane is 5.014 mm, and the net diameter is 1.803 mm; the curvature radius of the mirror surface of the second lens close to the image plane is -5.014 mm, and the net diameter is 1.745 mm;

[0032] The curvature radius of the mirror surface of the third lens close to the object plane is 6.215mm, and the net diameter is 1.731mm; the curvature radius of the middle cemented surface is 1.726mm, and the net diameter is 1.740mm; the curvature radius of the mirror surface of the third lens close to the image plane is -7.771mm, and the net diameter is 1.798mm;

[0033] The curvature radius of the mirror surface of the fourth lens close to the object plane is 2.975 mm, and the net diameter is 1.808 mm; the curvature radius of the mirror surface of the fourth lens close to the image plane is 20.983 mm, and the net diameter is 1.667 mm;

[0034] The curvature radius of the mirror surface of the fifth lens close to the object plane is -3.311 mm, and the clear aperture is 1.629 mm; the curvature radius of the mirror surface of the fifth lens close to the image plane is -3.358 mm, and the clear aperture is 1.805 mm;

[0035] The curvature radius of the mirror surface of the sixth lens close to the object plane is 2.191 mm, and the net diameter is 1.641 mm; the curvature radius of the mirror surface of the sixth lens close to the image plane is 0.889 mm, and the net diameter is 1.363 mm;

[0036] The mirror curvature radius of the seventh lens close to the object plane is 1.115 mm, and the net aperture is 1.537 mm; the mirror curvature radius of the seventh lens close to the image plane is 1.386 mm, and the net aperture is 1.090 mm.

[0037] Optionally, the coefficients of the aspheric lens close to the object plane are: K4=0.019, K6=-0.350, K8=0.151, K10=1.550, K12=-5.150, K14=6.497, K16=-3.230; the coefficients of the aspheric lens close to the image plane are K4=0.126, K6=-0.841, K8=1.401, K10=-1.121, K12=-1.457, K14=1.581, K16=-0.925.

[0038] Optionally, the system aperture surface is arranged between the third lens and the fourth lens to reduce the difficulty of aberration correction.

[0039] In a second aspect, the present invention further provides an endoscopic imaging probe, comprising an optical fiber bundle and a multi-marked endoscopic imaging lens for the digestive tract as described in any one of the first aspects, wherein the endoscopic imaging lens is coupled to the optical fiber bundle to form an endoscopic imaging probe.

[0040] Compared with the prior art, the above technical solutions conceived by the present invention can achieve the following

[0041] Beneficial effects:

[0042] 1. A multi-marked endoscopic imaging lens for the digestive tract. The first lens and the second lens are combined to limit the light beam within the effective aperture of the lens by combining seven spherical surfaces and one aspherical surface. The third lens uses a double-cemented achromatic lens to correct chromatic aberration. The fourth lens and the fifth lens are combined with positive and negative lenses to correct aberration. The sixth lens uses an aspherical lens to correct the spherical aberration brought by the spherical lens in the collimation and focusing system, while simplifying the system structure and facilitating processing. The seventh lens uses a meniscus lens, which is matched with the sixth lens to correct chromatic aberration to improve the imaging quality. The designed endoscopic imaging lens has an optical effective aperture of no more than 1.8mm, a mechanical outer diameter of the lens of 2.6mm, a working band of 488-860nm, a magnification of 2.14 times, and an imaging field of view of 450μm. The overall aberration is effectively corrected to ensure its imaging performance in the visible to near-infrared band, thereby realizing cell resolution imaging of the surface layer of the mucosa of the digestive tract tissue. The problem that the existing confocal endoscope has a single and limited fluorescence spectrum band and is difficult to distinguish information of different structural tissues in the body is solved. It can realize signal collection of multiple fluorescent dyes from visible light to near-infrared range, can match the excitation and fluorescence spectra of clinically available fluorescent contrast agents (including sodium fluorescein, methylene blue and indocyanine green), is compatible with the instrument channel of general endoscopes (including gastroscopes and colonoscopes) in the range of 2.8-3.8mm, enter the human body to collect multiple structures and cell information of different markers in esophageal, gastric and intestinal diseases, realize multi-information observation of digestive tract tissue structure and cells in vivo, and expand confocal endoscopy to in vivo / in situ multi-spectral fluorescence endoscopic imaging.

[0043] 2. A multi-marker endoscopic imaging lens for the digestive tract, which comprehensively considers parameters such as object-side numerical aperture, image-side numerical aperture and magnification, uses a double-cemented achromatic lens and a coating process to combine two glass materials to achieve chromatic aberration compensation. Combined with the adjustability of the aspheric lens, it maintains high-resolution performance in the visible to near-infrared band, solving the problems of difficulty in aberration correction and miniaturization design of wide-spectrum endoscopic imaging lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A diagram showing the optical path structure of a multi-marker endoscopic imaging lens for the digestive tract provided by the present invention;

[0045] Figure 2 An image-side spot diagram of a multi-marker endoscopic imaging lens provided by the present invention.

[0046] Figure 3 The MTF curves of the meridian plane and sagittal plane at six radial imaging positions of a multi-marker endoscopic imaging lens provided by the present invention and the MTF curve under the diffraction limit condition;

[0047] Figure 4 The image field curvature and distortion curve of a multi-marker endoscopic imaging lens provided by the present invention;

[0048] Figure 5 The optical path difference curves of a multi-marker endoscopic imaging lens provided by the present invention at six viewing fields in the image radial direction;

[0049] Figure 6 A color focus shift curve of a multi-marker endoscopic imaging lens provided by the present invention.

[0050] In the above figures, the reference numerals are:

[0051] L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; L5, fifth lens; L6, sixth lens; L7, seventh lens. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0053] The contents involved in the above embodiment are described below in conjunction with a preferred embodiment.

[0054] Embodiment 1

[0055] The present invention provides a multi-marked endoscopic imaging lens for the digestive tract, wherein the endoscopic imaging lens is a microscope objective lens group;

[0056] The first lens L1 is in direct contact with the organism to be tested, and is used to focus the laser and collect fluorescence signals at the same time; the second lens L2 is matched with the first lens L1 to limit the laser beam within the effective aperture; the third lens L3 adopts a double-cemented achromatic lens composed of a negative lens and a positive lens, which is used to correct chromatic aberration; the fourth lens L4 and the fifth lens L5 are respectively positive and negative lenses and are combined with each other to correct aberration; the sixth lens L6 adopts an aspherical lens to correct the spherical aberration brought by the spherical lens in the collimation and focusing system; the seventh lens L7 adopts a meniscus lens, which is matched with the sixth lens L6 to correct chromatic aberration to improve imaging quality.

[0057] like Figure 1As shown, a multi-label endoscopic imaging lens for the digestive tract provided by the present invention is generally designed in the form of a seven-group eight-piece structure. Through the combination of seven spherical surfaces and one aspherical surface, the overall aberration is effectively corrected to ensure imaging performance. The first lens is in direct contact with the organism to be tested, and is used to focus the laser and collect the fluorescence signal at the same time. The fluorescence signal is sequentially transmitted to the seventh lens through the second lens. The working spectrum range of the designed microscope objective lens group is 488-860nm, which ensures the excitation and fluorescence spectra of a variety of fluorescent dyes adapted to the visible light to near-infrared range. The effective aperture is less than 1.8mm, so that the mechanical outer diameter is not more than 2.6mm, and the numerical aperture at the object side or tissue is 0.55, which ensures the cell-level resolution of the lens, the imaging field of view is 450μm, the magnification is 2.14 times, and the working distance is 84μm, so as to realize the multi-information observation of the mucosal surface structure and cells. It achieves the effect of matching the excitation and fluorescence spectra of clinically available fluorescent contrast agents, and has a wide range of applications.

[0058] Optionally, the first lens L1 is made of H-LAF3B material;

[0059] The second lens L2 is made of H-ZK9B material;

[0060] The lens of the third lens L3 close to the object plane is made of H-ZF62 material, and the lens close to the image plane is made of H-LAK53 material;

[0061] The fourth lens L4 is made of H-LAF3B material;

[0062] The fifth lens L5 is made of H-ZF62 material;

[0063] The sixth lens L6 is made of polycarbonate resin EP10000;

[0064] The seventh lens L7 is made of H-ZF62 material.

[0065] Optionally, the first lens L1 is a plano-convex lens with a center thickness of 2.218 mm;

[0066] The second lens L2 is a biconvex lens with a center thickness of 1.216 mm;

[0067] The third lens L3 is a double cemented achromatic lens, the center thickness of the lens close to the object plane is 1.155 mm, and the center thickness of the lens close to the image plane is 0.783 mm;

[0068] The fourth lens L4 is a plano-convex lens with a center thickness of 0.692 mm;

[0069] The fifth lens L5 is a convex lens with a center thickness of 3.000 mm;

[0070] The sixth lens L6 is an aspherical lens with a center thickness of 0.343 mm;

[0071] The seventh lens L7 is a convex lens with a center thickness of 0.927 mm.

[0072] Optionally, the center distance between two adjacent surfaces of the first lens L1 and the second lens L2 is 0.100 mm;

[0073] The center distance between two adjacent surfaces of the second lens L2 and the third lens L3 is 0.100 mm;

[0074] The center distance between two adjacent surfaces of the third lens L3 and the fourth lens L4 is 0.100 mm;

[0075] The center distance between two adjacent surfaces of the fourth lens L4 and the fifth lens L5 is 0.219 mm;

[0076] The center distance between two adjacent surfaces of the fifth lens L5 and the sixth lens L6 is 0.100 mm;

[0077] The center distance between two adjacent surfaces of the sixth lens L6 and the seventh lens L7 is 0.283 mm;

[0078] The center distance between the seventh lens L7 and two adjacent surfaces of the optical fiber bundle is 0.360 mm.

[0079] Optionally, the clear aperture of the mirror surface of the first lens L1 close to the object plane is 0.514 mm; the curvature radius of the mirror surface of the first lens L1 close to the image plane is -1.557 mm, and the clear aperture is 1.741 mm;

[0080] The mirror curvature radius of the second lens L2 close to the object plane is 5.014 mm, and the net diameter is 1.803 mm; the mirror curvature radius of the second lens L2 close to the image plane is -5.014 mm, and the net diameter is 1.745 mm;

[0081] The mirror curvature radius of the third lens L3 close to the object plane is 6.215mm, and the net diameter is 1.731mm; the curvature radius of the middle cemented surface is 1.726mm, and the net diameter is 1.740mm; the mirror curvature radius of the third lens L3 close to the image plane is -7.771mm, and the net diameter is 1.798mm;

[0082] The mirror curvature radius of the fourth lens L4 close to the object plane is 2.975 mm, and the net diameter is 1.808 mm; the mirror curvature radius of the fourth lens L4 close to the image plane is 20.983 mm, and the net diameter is 1.667 mm;

[0083] The mirror curvature radius of the fifth lens L5 close to the object plane is -3.311 mm, and the clear aperture is 1.629 mm; the mirror curvature radius of the fifth lens L5 close to the image plane is -3.358 mm, and the clear aperture is 1.805 mm;

[0084] The mirror curvature radius of the sixth lens L6 close to the object plane is 2.191 mm, and the net diameter is 1.641 mm; the mirror curvature radius of the sixth lens L6 close to the image plane is 0.889 mm, and the net diameter is 1.363 mm;

[0085] The mirror curvature radius of the seventh lens L7 close to the object plane is 1.115 mm, and the net aperture is 1.537 mm; the mirror curvature radius of the seventh lens L7 close to the image plane is 1.386 mm, and the net aperture is 1.090 mm.

[0086] Optionally, the coefficients of the aspheric lens close to the object plane are: K4=0.019, K6=-0.350, K8=0.151, K10=1.550, K12=-5.150, K14=6.497, K16=-3.230; the coefficients of the aspheric lens close to the image plane are K4=0.126, K6=-0.841, K8=1.401, K10=-1.121, K12=-1.457, K14=1.581, K16=-0.925.

[0087] Furthermore, setting the system aperture surface between the double-cemented achromatic lens (the third lens) and the convex lens (the fourth lens) can further reduce the difficulty of aberration correction.

[0088] During the design process, the multi-marker endoscopic imaging lens was set as an image-space telecentric system, with an optical effective aperture of less than 1.8 mm and a mechanical outer diameter of 2.6 mm, which is compatible with the instrument channels of general endoscopes (including gastroscopes and colonoscopes) in the range of 2.8-3.8 mm. The working band of the endoscopic imaging lens designed according to the above parameters is 488-860 nm, covering the visible to near-infrared band, which is sufficient to match the fluorescence range of clinically available fluorescent contrast agents (including sodium fluorescein, methylene blue and indocyanine green), with a working distance of 84 μm and a magnification of 2.14 times, which can achieve cell-resolution imaging of the surface layer of the mucosa of the digestive tract tissue.

[0089] In order to match the numerical aperture of the optical fiber bundle, the numerical aperture of the multi-label endoscopic imaging lens at the image side or the optical fiber bundle end is 0.27, and the numerical aperture at the object side or the tissue is 0.55, thereby ensuring the cellular level resolution of the micro-objective lens.

[0090] Optionally, the distance between the microscope objective lens group and the biological tissue to be measured is adjustable, so as to generate high-resolution images at different depths.

[0091] Figure 2 This is an image point diagram of a multi-marker endoscopic imaging lens provided by the present invention. Six different fields of view, including on-axis, 0.3 field of view, 0.5 field of view, 0.707 field of view, 0.85 field of view and full field of view, were selected along the radial direction for full field of view image quality analysis. The root mean square radius of the diffuse spot in each field of view was 0.813μm, 0.892μm, 0.941μm, 0.940μm, 1.034μm and 1.094μm, respectively, which are all smaller than the diffraction limit of 1.277μm and smaller than the core radius of the commonly used image transmission fiber bundle of 2μm, which can maximize the coupling efficiency.

[0092] Figure 3 The MTF curves of the meridian and sagittal planes at the six radial imaging positions of a multi-marker endoscopic imaging lens provided by the present invention, as well as the MTF curves under the diffraction limit condition. As can be seen from the figure, the MTF curves of all fields of view are greater than 0.7 at the cutoff frequency, which greatly meets the design requirement that the MTF value should be greater than 0.5 at the cutoff frequency of the fiber bundle 132lp / mm, and further ensures that the endoscopic imaging resolution is not limited to the imaging performance of this embodiment.

[0093] Figure 4 The image-side field curvature and distortion curves of a multi-label endoscopic imaging lens provided by the present invention. As can be seen from the figure, the design wavelengths of this embodiment are 488nm, 515nm, 550nm, 785nm, 820nm, and 860nm, and the astigmatism and field curvature in the full field of view are fully constrained and corrected. The maximum field curvature of the image side in the full field of view is 8.49μm, which is 2.47μm when converted to the object side, which is less than the axial resolution of the confocal endoscopy system and meets the design requirements. The maximum value of the image-side astigmatism of each wavelength is 6.18μm, which is 1.80μm when converted to the object side, which maximizes the coupling efficiency of each wavelength in the wide spectrum fluorescence band. The distortion in the entire field of view is less than 2.51%, which is less than the limit that the human eye can recognize, and meets the design requirements.

[0094] Figure 5 The optical path difference curves of a multi-marker endoscopic imaging lens provided by the present invention at 6 radial fields of view on the image side, wherein the optical path difference of the curve at a wavelength of 550nm at 0.5 fields of view is the largest, and can reach a maximum of 0.54λ at the edge of the pupil. The optical path differences of the remaining curves are all less than half a wavelength. It can be considered that this embodiment achieves performance close to the diffraction limit.

[0095] Figure 6The chromatic focal shift curve of a multi-label endoscopic imaging lens provided by the present invention shows that the maximum focal shift change on the image side within the design wavelength range is 12.3250 μm, and the maximum focal shift on the object side is 3.58 μm, which is smaller than the axial resolution of the confocal endoscopy system. It can be considered that the chromatic aberration of this embodiment is fully corrected, thereby improving the collection and imaging performance of wide-spectrum fluorescence.

[0096] The embodiment of the present invention provides a multi-label endoscopic imaging lens for the digestive tract. By combining seven spherical surfaces with one aspherical surface, the designed endoscopic imaging lens has an optical effective aperture of no more than 1.8 mm, a mechanical outer diameter of the lens of 2.6 mm, a working band of 488-860 nm, a magnification of 2.14 times, and an imaging field of view of 450 μm. It solves the technical problem that the working band range of the endoscopic imaging lens cannot simultaneously match the fluorescence spectrum bands marked by different fluorescent dyes, resulting in difficulty in distinguishing different structural tissue information in the body, and realizes effective correction of overall aberrations to ensure its imaging performance in the visible to near-infrared band, thereby realizing cell-resolution imaging of the mucosal surface of digestive tract tissues. It realizes the signal collection of multiple fluorescent dyes from the visible to near-infrared range, and can match the excitation and fluorescence spectra of clinically available fluorescent contrast agents (including sodium fluorescein, methylene blue, and indocyanine green).

[0097] Embodiment 2

[0098] The present invention also provides an endoscopic imaging probe, comprising an optical fiber bundle and a multi-marked endoscopic imaging lens for the digestive tract as described in any one of the first embodiments, wherein the endoscopic imaging lens is coupled to the optical fiber bundle to form an endoscopic imaging probe.

[0099] By cooperating with a multi-marker endoscopic imaging lens for the digestive tract, an endoscopic imaging lens fiber bundle is obtained to achieve multi-information observation of the digestive tract tissue structure and cells in the body. The fiber bundle is bonded to form an endoscopic imaging probe, which is compatible with the instrument channel of general endoscopes (including gastroscopes and colonoscopes) in the range of 2.8-3.8mm, enters the human body to collect various structural and cell information of different markers in esophageal, stomach and intestinal diseases, and expands the confocal endoscope to in vivo / in situ multi-spectral fluorescence endoscopic imaging.

[0100] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-marker endoscopic imaging lens for the digestive tract, characterized in that: The endoscopic imaging lens is a microscope objective lens group; The microscope objective lens group includes, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens; The first lens is in direct contact with the organism to be tested, and is used to focus the laser and collect fluorescence signals at the same time; the second lens is matched with the first lens to limit the laser beam within the effective aperture; the third lens adopts a double-cemented achromatic lens composed of a negative lens and a positive lens, which is used to correct chromatic aberration; the fourth lens and the fifth lens are respectively positive and negative lenses and are combined with each other to correct aberration; the sixth lens adopts an aspherical lens to correct the spherical aberration caused by the spherical lens in the collimation and focusing system; the seventh lens adopts a meniscus lens, which is matched with the sixth lens to correct chromatic aberration to improve imaging quality.

2. The endoscopic imaging lens according to claim 1, wherein: The working spectrum range of the microscope objective lens group is 488-860nm, the effective aperture is less than 1.8mm, the numerical aperture at the object side or tissue is 0.55, the imaging field of view is 450μm, the magnification is 2.14 times, and the working distance is 84μm.

3. The endoscopic imaging lens according to claim 1, wherein: The first lens is made of H-LAF3B material; The second lens is made of H-ZK9B material; The third lens is made of H-ZF62 material for the lens close to the object plane and H-LAK53 material for the lens close to the image plane; The fourth lens is made of H-LAF3B material; The fifth lens is made of H-ZF62 material; The sixth lens is made of polycarbonate resin EP10000; The seventh lens is made of H-ZF62 material.

4. The endoscopic imaging lens according to claim 3, wherein: The first lens is a plano-convex lens with a center thickness of 2.218 mm; The second lens is a biconvex lens with a center thickness of 1.216 mm; The third lens is a double cemented achromatic lens, the center thickness of the lens close to the object plane is 1.155 mm, and the center thickness of the lens close to the image plane is 0.783 mm; The fourth lens is a plano-convex lens with a center thickness of 0.692 mm; The fifth lens is a convex lens with a center thickness of 3.000 mm; The sixth lens is an aspherical lens with a center thickness of 0.343 mm; The seventh lens is a convex lens with a center thickness of 0.927 mm.

5. The endoscopic imaging lens according to claim 3, wherein: The center distance between the two adjacent surfaces of the first lens and the second lens is 0.100 mm; The center distance between two adjacent surfaces of the second lens and the third lens is 0.100 mm; The center distance between two adjacent surfaces of the third lens and the fourth lens is 0.100 mm; The center distance between two adjacent surfaces of the fourth lens and the fifth lens is 0.219 mm; The center distance between two adjacent surfaces of the fifth lens and the sixth lens is 0.100 mm; The center distance between two adjacent surfaces of the sixth lens and the seventh lens is 0.283 mm; The center distance between the seventh lens and two adjacent surfaces of the optical fiber bundle is 0.360 mm.

6. The endoscopic imaging lens according to claim 3, wherein: The clear aperture of the mirror surface of the first lens close to the object plane is 0.514 mm; the curvature radius of the mirror surface of the first lens close to the image plane is -1.557 mm, and the clear aperture is 1.741 mm; The curvature radius of the mirror surface of the second lens close to the object plane is 5.014 mm, and the net diameter is 1.803 mm; the curvature radius of the mirror surface of the second lens close to the image plane is -5.014 mm, and the net diameter is 1.745 mm; The curvature radius of the mirror surface of the third lens close to the object plane is 6.215mm, and the net diameter is 1.731mm; the curvature radius of the middle cemented surface is 1.726mm, and the net diameter is 1.740mm; the curvature radius of the mirror surface of the third lens close to the image plane is -7.771mm, and the net diameter is 1.798mm; The curvature radius of the mirror surface of the fourth lens close to the object plane is 2.975 mm, and the net diameter is 1.808 mm; the curvature radius of the mirror surface of the fourth lens close to the image plane is 20.983 mm, and the net diameter is 1.667 mm; The curvature radius of the mirror surface of the fifth lens close to the object plane is -3.311 mm, and the clear aperture is 1.629 mm; the curvature radius of the mirror surface of the fifth lens close to the image plane is -3.358 mm, and the clear aperture is 1.805 mm; The curvature radius of the mirror surface of the sixth lens close to the object plane is 2.191 mm, and the net diameter is 1.641 mm; the curvature radius of the mirror surface of the sixth lens close to the image plane is 0.889 mm, and the net diameter is 1.363 mm; The mirror curvature radius of the seventh lens close to the object plane is 1.115 mm, and the net aperture is 1.537 mm; the mirror curvature radius of the seventh lens close to the image plane is 1.386 mm, and the net aperture is 1.090 mm.

7. The endoscopic imaging lens according to claim 2, wherein: The coefficients of the aspheric lens close to the object plane are: K4=0.019, K6=-0.350, K8=0.151, K10=1.550, K12=-5.150, K14=6.497, K16=-3.230; the coefficients of the aspheric lens close to the image plane are K4=0.126, K6=-0.841, K8=1.401, K10=-1.121, K12=-1.457, K14=1.581, K16=-0.

925.

8. The endoscopic imaging lens according to claim 1, wherein: The system aperture surface is arranged between the third lens and the fourth lens to reduce the difficulty of aberration correction.

9. An endoscopic imaging probe, characterized in that: It comprises an optical fiber bundle and a multi-marker endoscopic imaging lens for the digestive tract as described in any one of claims 1 to 8, wherein the endoscopic imaging lens is coupled to the optical fiber bundle to form an endoscopic imaging probe.

Images