Multi-marked endoscopic imaging lens for digestive tract

Abstract

The application discloses a multi-marked endoscopic imaging lens for digestive tract, and belongs to the field of biomedical microscopic endoscopic imaging. 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; the second lens is matched with the first lens to limit a light beam in an effective light aperture of the lens; the third lens corrects chromatic aberration; the fourth lens and the fifth lens are combined to correct aberration; the sixth lens adopts an aspheric lens to correct spherical aberration caused in a collimating and focusing system; and the seventh lens is matched with the sixth lens to correct chromatic aberration. The working spectral range of the microscopic objective lens group is 488-860 nm, the effective light aperture is less than 1.8 mm, the mechanical outer diameter is not greater than 2.6 mm, the numerical aperture at the object side or the tissue is 0.55, the imaging field of view is 450 microns, the magnification is 2.14 times, and the working distance is 84 microns. The effect of matching excitation and fluorescence spectrum of a clinically available fluorescence contrast agent is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of biomedical microscopic endoscopic imaging, and more particularly relates to a multi-label endoscopic imaging lens for the digestive tract. BACKGROUND

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

[0003] In order to simultaneously collect different structural / cellular information marked by different fluorescent dyes, it is necessary to expand the working waveband to achieve a wide spectrum covering the visible light to the near-infrared region, and the resulting problem is that it is difficult to correct the aberration of the wide-spectrum endoscopic imaging lens and to design a miniaturized lens. SUMMARY

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

[0005] To achieve the above-mentioned purpose, in a first aspect, the present application provides a multi-label endoscopic imaging lens for the digestive tract, wherein the endoscopic imaging lens is a microscopic objective lens group.

[0006] The microscopic objective lens group comprises, in order 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 biological object to be measured and is used to focus the laser and simultaneously collect the fluorescence signal; the second lens, in cooperation with the first lens, limits the laser beam within the effective clear aperture; the third lens is a double cemented achromatic lens formed by cementing a negative lens and a positive lens, and is used to correct chromatic aberration; the fourth lens and the fifth lens are positive and negative lenses, respectively, and are combined with each other to correct aberration; the sixth lens is an aspheric lens, which is used to correct the spherical aberration caused by the spherical lens in the collimation and focusing system; and the seventh lens is a meniscus lens, which is used to correct chromatic aberration in cooperation with the sixth lens to improve the imaging quality.

[0008] Optionally, the working spectrum range of the microscopic objective lens group is 488-860nm, the effective clear aperture is less than 1.8mm, the numerical aperture at the object side or the 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 adopts H-LAF3B material;

[0010] The second lens adopts H-ZK9B material;

[0011] The third lens adopts H-ZF62 material near the object plane and adopts H-LAK53 material near the image plane;

[0012] The fourth lens adopts H-LAF3B material;

[0013] The fifth lens adopts H-ZF62 material;

[0014] The sixth lens adopts polycarbonate resin EP10000;

[0015] The seventh lens adopts H-ZF62 material.

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

[0017] The second lens adopts a double-convex lens with a center thickness of 1.216mm;

[0018] The third lens adopts a double cemented achromatic lens with a center thickness of 1.155mm near the object plane and a center thickness of 0.783mm near the image plane;

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

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

[0021] The sixth lens adopts an aspheric lens with a center thickness of 0.343mm;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0037] Optionally, the coefficients of the aspherical 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, and K16=-3.230; and the coefficients of the aspherical 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, and K16=-0.925.

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

[0039] In a second aspect, the present application further provides an endoscopic imaging probe, which comprises a fiber bundle and a multi-marked endoscopic imaging lens for the digestive tract according to any one of the first aspect, and the endoscopic imaging lens is coupled to the fiber bundle to form the endoscopic imaging probe.

[0040] By means of the above technical scheme of the present application, compared with the prior art, the following advantages can be achieved

[0041] Advantages:

[0042] 1. A multi-label endoscopic imaging lens for digestive tract, by means of combination of seven spherical surfaces and one aspherical surface, the first lens and the second lens are matched to limit the light beam within the effective aperture of the lens, the third lens adopts double cemented achromatic lens to correct chromatic aberration, the fourth lens and the fifth lens are matched by positive and negative lens combination to correct aberration, the sixth lens adopts aspherical lens to correct spherical aberration caused by spherical lens in collimating and focusing system, and simplify the system structure and facilitate processing, and the seventh lens adopts meniscus lens matched with the sixth lens to correct chromatic aberration and improve imaging quality. The designed endoscopic imaging lens has optical effective aperture not greater than 1.8 mm, mechanical outer diameter of the lens is 2.6 mm, working waveband is 488-860 nm, magnification is 2.14 times, and imaging field of view is 450 μm; overall aberration is effectively corrected to ensure the imaging performance in visible light to near infrared waveband, so that the cell resolution imaging of the mucosal surface layer of digestive tract tissue is realized. The problems that the existing confocal endoscope has single and limited fluorescent spectral band and is difficult to distinguish different structural tissue information in vivo are solved. The signal collection of multiple fluorescent dyes from visible light to near infrared range is realized, the excitation and fluorescent spectrum of the clinically available fluorescent contrast agent (including fluorescein sodium, methylene blue and indocyanine green) can be matched, the instrument channel in the range of 2.8-3.8 mm of general endoscope (including gastroscope and colonoscope) can be compatible, different markers of multiple structures and cell information in esophageal, stomach and intestinal diseases in human body can be collected, the multi-information observation of in vivo digestive tract tissue structure and cells is realized, and the confocal endoscope is expanded to multispectral fluorescent endoscopic imaging in vivo / in situ.

[0043] 2. A multi-label endoscopic imaging lens for digestive tract, considering the parameters of object numerical aperture, image numerical aperture and magnification, using the color aberration correction means of color aberration compensation by mutual combination of two kinds of glass materials of double cemented achromatic lens and coating process, and the adjustability of aspherical lens, the performance of high resolution in visible light to near infrared waveband is maintained, and the problems of wide spectrum endoscopic imaging lens that aberration correction is difficult and miniaturization design is difficult are solved. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 A light path structure diagram of a multi-label endoscopic imaging lens for digestive tract provided by the present application;

[0045] Figure 2 An image side point array diagram of a multi-label endoscopic imaging lens provided by the present application.

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

[0047] Figure 4 A field curvature and distortion curve of an image side of a multi-mark endoscopic imaging lens provided by the present application;

[0048] Figure 5 An optical path difference curve of a multi-mark endoscopic imaging lens provided by the present application at six radial fields of view of an image side;

[0049] Figure 6 A chromatic focal shift curve of a multi-mark endoscopic imaging lens provided by the present application.

[0050] In the above figures, the reference signs 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 objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0053] The content involved in the above examples is described below in combination with a preferred embodiment.

[0054] Example 1

[0055] The present application provides a multi-mark endoscopic imaging lens for a digestive tract, which is a microscopic objective lens group.

[0056] The first lens L1 is directly in contact with a biological object to be measured for focusing a laser and collecting a fluorescent signal; the second lens L2 is matched with the first lens L1 to limit a laser beam within an effective clear aperture; the third lens L3 is a double cemented achromatic lens formed by cementing a negative lens and a positive lens together for correcting chromatic aberration; the fourth lens L4 and the fifth lens L5 are positive and negative lenses, respectively, and are combined with each other for correcting aberration; the sixth lens L6 is an aspheric lens for correcting spherical aberration caused by a spherical lens in a collimating and focusing system; and the seventh lens L7 is a meniscus lens matched with the sixth lens L6 for correcting chromatic aberration to improve imaging quality.

[0057] As Figure 1As shown, the application provides a multi-label endoscopic imaging lens for digestive tract, the overall design adopts a structure form of seven groups and eight pieces, through the combination of seven spherical surfaces and one aspherical surface, the overall aberration is effectively corrected to ensure the imaging performance. The first lens directly contacts with the biological to be measured for focusing laser and collecting fluorescent signal, and the fluorescent signal is transmitted to the seventh lens in sequence through the second lens. The working spectral range of the designed microscope objective group is 488-860nm, which ensures the excitation and fluorescent spectrum of various fluorescent dyes in the visible light to near infrared range, the effective clear aperture is less than 1.8mm, the mechanical outer diameter is not greater than 2.6mm, 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 mucosal surface structure and cells. The excitation and fluorescent spectrum of the fluorescent contrast agent available in clinic are matched, and the effect of wide application range is realized.

[0058] Optionally, the first lens L1 adopts H-LAF3B material;

[0059] The second lens L2 adopts H-ZK9B material;

[0060] The third lens L3 adopts H-ZF62 material near the object surface, and adopts H-LAK53 material near the image surface;

[0061] The fourth lens L4 adopts H-LAF3B material;

[0062] The fifth lens L5 adopts H-ZF62 material;

[0063] The sixth lens L6 adopts polycarbonate resin EP10000;

[0064] The seventh lens L7 adopts H-ZF62 material.

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

[0066] The second lens L2 adopts a double convex lens with a center thickness of 1.216mm;

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

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

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

[0070] The sixth lens L6 adopts an aspherical lens, and the center thickness is 0.343 mm;

[0071] The seventh lens L7 adopts a convex lens, and the center thickness is 0.927 mm.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0086] Optionally, the coefficients of the aspheric lens near 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 near 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] Further, the system stop plane is arranged between the doublet apochromatic lens (the third lens) and the convex lens (the fourth lens), which can further reduce the difficulty of aberration correction.

[0088] In the design process, the multi-mark endoscopic imaging lens is set as an image-side telecentric system, the optical effective light aperture is less than 1.8 mm, the mechanical outer diameter of the lens is 2.6 mm, and the lens can be compatible with the instrument channel in the range of 2.8-3.8 mm of a general endoscope (including a gastroscope and a colonoscope). The working waveband of the endoscopic imaging lens designed according to the above parameters is 488-860 nm, covering the visible light to near-infrared waveband, which is sufficient to match the fluorescence range of the clinically available fluorescent contrast agent (including sodium fluorescein, methylene blue and indocyanine green), the working distance is 84 μm, the magnification is 2.14 times, and the cell resolution imaging of the mucosal surface layer of the digestive tract tissue can be realized.

[0089] In order to match the numerical aperture of the fiber bundle, the numerical aperture of the image side or the fiber bundle end of the multi-mark endoscopic imaging lens is 0.27, and the numerical aperture of the object side or the tissue is 0.55, which ensures the cell level resolution of the micro objective lens.

[0090] Optionally, the distance between the microscopic 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 A point spread function of the multi-mark endoscopic imaging lens is provided. Six different fields of view, i.e., 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, are selected along the radial direction for full field of view image quality analysis. The root mean square radius of the diffraction spot in each field of view is 0.813 μm, 0.892 μm, 0.941 μm, 0.940 μm, 1.034 μm and 1.094 μm, respectively, which is less than the diffraction limit of 1.277 μm and also less than the core radius of 2 μm of the commonly used image fiber bundle, so that the coupling efficiency can be maximized.

[0092] Figure 3 MTF curves of the meridional plane and the sagittal plane of six radial imaging positions of the multi-mark endoscopic imaging lens and the MTF curve under the diffraction limit condition are provided. As shown in 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 132 lp / mm of the fiber bundle, and further ensures that the endoscopic imaging resolution is not limited by the imaging performance of the embodiment.

[0093] Figure 4 Image field curvature and distortion curves of the multi-mark endoscopic imaging lens are provided. As shown in the figure, the design wavelengths of the embodiment are 488 nm, 515 nm, 550 nm, 785 nm, 820 nm and 860 nm, and the astigmatism and field curvature in the full field of view are fully constrained and corrected. The maximum image field curvature in the image space is 8.49 μm, which is converted to 2.47 μm in the object space, which is less than the axial resolution of the confocal endoscopic system and meets the design requirements. The maximum image astigmatism of each wavelength is 6.18 μm, which is converted to 1.80 μm in the object space, thereby maximizing the coupling efficiency of each wavelength in the wide spectrum fluorescent band. The distortion in the entire field of view is less than 2.51%, which is less than the limit that can be recognized by the human eye and meets the design requirements.

[0094] Figure 5 The optical path difference curves of the multi-mark endoscopic imaging lens at six radial fields of view in the image space are provided. The maximum optical path difference of the 550 nm wavelength at the 0.5 field of view is 0.54λ at the pupil edge, and the optical path differences of the other curves are less than half a wavelength, so that the embodiment can be considered to achieve the approximate diffraction limit performance.

[0095] Figure 6The color focal shift curve of the multi-label endoscopic imaging lens provided by the application is shown in the figure, from which it can be seen that the maximum focal shift change in the design wavelength range is 12.3250 μm, and the maximum focal length displacement of the object side is 3.58 μm, which is smaller than the axial resolution of the confocal endoscopic system, and the chromatic aberration of the embodiment can be considered to be fully corrected, and the collection and imaging performance of the wide-spectrum fluorescence are improved.

[0096] The multi-label endoscopic imaging lens for the digestive tract provided by the embodiment of the application is designed by combining seven spherical surfaces and one aspherical surface, and has an optical effective aperture not greater than 1.8 mm, a mechanical outer diameter of 2.6 mm, a working waveband of 488-860 nm, a magnification of 2.14 times, and an imaging field of view of 450 μm; the technical problem that the working waveband range of the endoscopic imaging lens cannot simultaneously match the fluorescence spectral bands of different fluorescent dyes, resulting in difficulty in distinguishing different structural tissue information in the body, is solved, the overall aberration is effectively corrected, the imaging performance in the visible light to near-infrared waveband is ensured, and thus the cell resolution imaging of the mucosal surface layer of the digestive tract tissue is realized. The signal collection of multiple fluorescent dyes from the visible light to the near-infrared range is realized, and the excitation and fluorescence spectrum of the clinically available fluorescent contrast agent (including fluorescein sodium, methylene blue and indocyanine green) can be matched.

[0097] Embodiment two

[0098] The application further provides an endoscopic imaging probe, which comprises a fiber bundle and the multi-label endoscopic imaging lens for the digestive tract according to any one of the embodiment one, and the endoscopic imaging lens is coupled to the fiber bundle to form the endoscopic imaging probe.

[0099] The multi-label endoscopic imaging lens for the digestive tract is matched to obtain an endoscopic imaging lens fiber bundle, which realizes the multi-information observation of the in-vivo digestive tract tissue structure and cells. The fiber bundle is bonded to form an endoscopic imaging probe, which can be compatible with the instrument channel in the range of 2.8-3.8 mm of a general endoscope (including a gastroscope and a colonoscope), enters the human body to collect the multiple structure and cell information of different markers in the esophagus, stomach and intestinal diseases, and expands the confocal endoscope to the in-vivo / in-situ multi-spectral fluorescence endoscopic imaging.

[0100] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the application, and is not used to limit the application, and any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A multi-label 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, from the object side to the image side, includes: 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 under test, used to focus the laser while collecting fluorescence signals; the second lens, in combination with the first lens, confines the beam within the effective aperture; the third lens is a cemented doublet achromatic lens composed of a negative lens and a positive lens, used to correct chromatic aberration; the fourth and fifth lenses, through a combination of positive and negative lenses, are used to correct aberrations; the sixth lens is an aspherical lens, used to correct spherical aberration introduced by spherical lenses in the collimation and focusing system; the seventh lens is a convex-concave lens, used in combination with the sixth lens, to correct chromatic aberration and improve image quality; The microscope objective lens group consists of eight lenses, with the optical power combinations being positive, positive, negative, positive, positive, negative, negative, positive in sequence; The microscope objective lens group has a working spectral range of 488-860 nm, an effective aperture of less than 1.8 mm, a numerical aperture of 0.55 at the object or tissue level, an imaging field of view of 450 μm, a magnification of 2.14 times, and a working distance of 84 μm.

2. The endoscopic imaging lens as described in claim 1, characterized in that, 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 near the object plane and H-LAK53 material for the lens near 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.

3. The endoscopic imaging lens as described in claim 2, characterized in that, 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 cemented doublet achromatic lens, with a center thickness of 1.155 mm near the object plane and a center thickness of 0.783 mm near the image plane. The fourth lens is a convex-concave lens with a center thickness of 0.692 mm; The fifth lens is a concave-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-concave lens with a center thickness of 0.927 mm.

4. The endoscopic imaging lens as described in claim 2, characterized in that, The center-to-center distance between two adjacent surfaces of the first lens and the second lens is 0.100 mm; The center-to-center distance between two adjacent surfaces of the second and third lenses is 0.100 mm; The center-to-center distance between two adjacent surfaces of the third and fourth lenses is 0.100 mm; The center-to-center distance between two adjacent surfaces of the fourth and fifth lenses is 0.219 mm; The center-to-center distance between two adjacent surfaces of the fifth and sixth lenses is 0.100 mm; The center-to-center distance between two adjacent surfaces of the sixth and seventh lenses is 0.283 mm; The center-to-center distance between the seventh lens and the two adjacent surfaces of the fiber bundle is 0.360 mm.

5. The endoscopic imaging lens as described in claim 2, characterized in that, The net aperture of the first lens near the object plane is 0.514m; the radius of curvature of the first lens near the image plane is -1.557mm, and the net aperture is 1.741mm. The second lens has a mirror curvature radius of 5.014 mm near the object plane and a net aperture of 1.803 mm; the second lens has a mirror curvature radius of -5.014 mm near the image plane and a net aperture of 1.745 mm. The radius of curvature of the third lens near the object plane is 6.215 mm, and the net aperture is 1.731 mm; the radius of curvature of the cemented surface in the middle is 1.726 mm, and the net aperture is 1.740 mm; the radius of curvature of the third lens near the image plane is -7.771 mm, and the net aperture is 1.798 mm. The fourth lens has a mirror curvature radius of 2.975 mm near the object plane and a net aperture of 1.808 mm; the fourth lens has a mirror curvature radius of 20.983 mm near the image plane and a net aperture of 1.667 mm. The fifth lens has a mirror curvature radius of -3.311 mm near the object plane and a light-transmitting aperture of 1.629 mm; the fifth lens has a mirror curvature radius of -3.358 mm near the image plane and a light-transmitting aperture of 1.805 mm. The sixth lens has a mirror curvature radius of 2.191 mm near the object plane and a net aperture of 1.641 mm; the sixth lens has a mirror curvature radius of 0.889 mm near the image plane and a net aperture of 1.363 mm. The seventh lens has a mirror curvature radius of 1.115 mm near the object plane and a net aperture of 1.537 mm; the seventh lens has a mirror curvature radius of 1.386 mm near the image plane and a net aperture of 1.090 mm.

6. The endoscopic imaging lens as described in claim 1, characterized in that, The coefficients of the aspherical lens near 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 aspherical lens near 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.

7. The endoscopic imaging lens as described in claim 1, characterized in that, The system aperture is positioned between the third and fourth lenses to reduce the difficulty of aberration correction.

8. An endoscopic imaging probe, characterized in that, It includes an optical fiber bundle and a multi-marker endoscopic imaging lens for the digestive tract as described in any one of claims 1-7, wherein the endoscopic imaging lens is coupled to the optical fiber bundle to form an endoscopic imaging probe.

Images