Confocal probe catheter and confocal microscopic imaging instrument

Abstract

The utility model discloses a confocal probe catheter confocal microscopic imaging instrument. The confocal probe catheter comprises an optical fiber bundle, a coupling objective lens group and an objective lens connecting sleeve, the objective lens connecting sleeve comprises an objective lens positioning part and an optical fiber connecting part, the objective lens positioning part and the optical fiber connecting part are hollow and coaxial, the coupling objective lens group is arranged in the objective lens positioning part, and the near end of the optical fiber bundle is arranged in the optical fiber connecting part. The objective lens connecting sleeve enables the near end of the optical fiber bundle installed in the objective lens connecting sleeve to be coaxial with the coupling objective lens set, and images on the end face of the optical fiber bundle can be clearly imaged on the image plane of the coupling objective lens set only by adjusting the distance between the coupling objective lens set and the optical fiber bundle in the axial direction. After the optimal imaging position between the coupling objective lens group and the end face of the optical fiber bundle is fixed, the formed confocal probe catheter can be directly butted with a confocal host for use, focusing is not needed, and the inspection time can be effectively shortened.

Description

Technical Field

[0001] The utility model belongs to the field of biomedical imaging, and more specifically relates to a confocal probe catheter and a confocal microscopic imaging instrument. Background Art

[0002] With the maturity of laser technology and fiber optic imaging technology, confocal laser microscopy technology is becoming more and more widely used in clinical pathological biopsy. The current probe-type confocal microendoscope (pCLE) uses a confocal probe to connect to the optical system of the confocal host to obtain submicroscopic images. The probe-type confocal microendoscope (pCLE) is a medical device that can enter the natural cavity of the human body with the help of channels such as gastroscopes and colonoscopes to obtain local histological images to achieve accurate diagnosis of tiny lesions, gastrointestinal lesions, early gastrointestinal cancer and other lesions. Because it is fast, accurate and non-invasive, it may replace traditional endoscopic biopsy and pathological examination in the near future.

[0003] As described in patents such as CN1681432A, CN107065077B, CN108761653B, CN210605191 U, and CN109459848B, current probe-based confocal microendoscopes generally consist of two components: a confocal main unit and a confocal probe. The former primarily includes a laser, beam expander, dichroic mirror, two-dimensional scanning mechanism, relay lens, coupling objective lens, pinhole, and detector; the latter primarily comprises a fiber bundle and a micro-objective lens. The former achieves optical signal coupling and transmission by moving the coupling objective lens to align its focal plane with the end face of the fiber bundle.

[0004] As described in patents CN112904548A and CN117392701A, the movement of the coupled objective lens in the confocal mainframe is a focusing process. Considering factors such as motion accuracy and image recognition, this focusing process takes at least 2-3 minutes. Confocal endoscopy examinations are typically short, such as within 10 minutes. Therefore, the time required to focus and position the coupled objective lens and the fiber bundle is relatively long, which reduces the physician's operating experience and the efficiency of confocal endoscopy. Utility Model Content

[0005] In response to the above defects or improvement needs of the existing technology, the present invention provides a confocal probe catheter and a confocal microscope, which aims to solve the problem that the focusing positioning between the confocal host and the confocal probe is required during the existing confocal imaging process, which is time-consuming.

[0006] To achieve the above objectives, according to one aspect of the present invention, a confocal probe catheter is provided, comprising an optical fiber bundle, a coupled objective lens group, and an objective lens connecting sleeve, wherein the objective lens connecting sleeve comprises an objective lens positioning portion and an optical fiber connecting portion, wherein the interiors of the objective lens positioning portion and the optical fiber connecting portion are hollow and coaxial, the coupled objective lens group is disposed in the objective lens positioning portion, and the proximal end of the optical fiber bundle is disposed in the optical fiber connecting portion.

[0007] Through this technical solution, the objective lens connector sleeve places the proximal end of the fiber bundle mounted within it coaxially with the coupled objective lens assembly. Simply adjusting the distance between the coupled objective lens assembly and the fiber bundle in the axial direction allows for a clear image of the fiber bundle end face on the coupled objective lens assembly's image plane. Once the optimal imaging distance between the coupled objective lens assembly and the fiber bundle end face is fixed, the resulting confocal probe catheter can be directly docked with the confocal mainframe, eliminating the need for focusing and effectively reducing inspection time.

[0008] Furthermore, the confocal probe catheter also includes an objective lens end cover, which is arranged at the end of the objective lens positioning part away from the optical fiber connection part, and glue is filled between the objective lens end cover, the coupling objective lens group and the objective lens connecting sleeve.

[0009] Furthermore, the confocal probe catheter further includes a proximal ferrule, the proximal end of the optical fiber bundle is arranged in the proximal ferrule, and the proximal ferrule is arranged in the optical fiber connecting portion.

[0010] Furthermore, the confocal probe catheter also includes a proximal end of a plug, which includes a connecting sleeve positioning portion and a core connecting portion. The interiors of the connecting sleeve positioning portion and the core connecting portion are hollow, the objective lens connecting sleeve is arranged in the connecting sleeve positioning portion, and the proximal core is arranged in the core connecting portion.

[0011] Furthermore, the coupled objective lens group includes a fifth lens, a fourth lens, a third lens, a second lens, and a first lens arranged in sequence along the optical axis from the objective lens end cover to the optical fiber bundle, wherein the first lens has a concave surface facing the image side and a convex surface facing the object side, the second lens has a convex surface facing the image side and a flat surface facing the object side, the third lens has a flat surface facing the image side and a convex surface facing the object side, the fourth lens has a concave surface facing the image side and a convex surface facing the object side, and the fifth lens has a convex surface facing the image side and a convex surface facing the object side.

[0012] Furthermore, the total optical length of the coupled objective lens group is TTL, 13.5 mm < TTL < 17.3 mm, and the maximum outer diameter is BD, 2.79 mm < BD < 2.94 mm.

[0013] Furthermore, when the surface of the fifth lens facing the object side is convex, a sixth lens is further arranged between the fifth lens and the image side, and both surfaces of the sixth lens are flat surfaces.

[0014] According to another aspect of the present invention, a confocal microscope is provided, comprising a confocal mainframe and the aforementioned confocal probe catheter, wherein the confocal mainframe comprises a housing and a laser, a beam expander lens group, a dichroic mirror, a two-position scanning mechanism, a relay lens group, a pinhole lens, and a detector within the housing, wherein a probe connection mechanism is provided on one side of the housing, and the confocal probe catheter is fixed in the probe connection mechanism.

[0015] Furthermore, it also includes a miniature objective lens at the distal end of the optical fiber bundle.

[0016] In general, the utility model has the following advantages:

[0017] (1) The coupling objective lens group is integrated into the confocal probe to form a confocal probe catheter that does not require focusing, which can effectively reduce the confocal examination time;

[0018] (2) The optical design of the coupling objective lens group was carried out to reduce its length and outer diameter. The obtained coupling objective lens group is smaller in size and is convenient for combining with the confocal probe;

[0019] (3) The axial positioning of the optical fiber bundle and the coupled objective lens group is achieved through the structures such as the objective lens connecting sleeve, the proximal ferrule, and the proximal end of the plug to ensure that the two are concentric. The installation and adjustment process is simpler. Only the distance between the two can be adjusted axially to find the optimal imaging distance.

[0020] (4) The coupling objective lens group is installed at the proximal end of the optical fiber bundle, which can protect the proximal end of the optical fiber bundle and prevent the proximal end of the optical fiber bundle from being directly exposed and damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a cross-sectional diagram of the confocal probe catheter. Figure 1 ;

[0022] Figure 2 This is a cross-sectional diagram of the confocal probe catheter. Figure 2 ;

[0023] Figure 3 This is a cross-sectional diagram of the confocal probe catheter. Figure 3 ;

[0024] Figure 4 This is a cross-sectional diagram of the confocal probe catheter. Figure 4 ;

[0025] Figure 5This is a schematic diagram of the overall structure of the connection process between the proximal end of the plug and the handle in the confocal probe catheter;

[0026] Figure 6 This is a schematic diagram of the overall structure of the confocal probe catheter after the proximal end of the plug and the handle are connected;

[0027] Figure 7 is a schematic diagram of the overall structure of a coupled objective lens assembly in some embodiments;

[0028] Figure 8 is a schematic diagram of the overall structure of the coupled objective lens group in other embodiments;

[0029] Figure 9 (a) is a diagram showing the state of the confocal probe guide tube during installation and adjustment;

[0030] Figure 9 Middle (b) is a diagram showing the confocal probe guide tube after installation and adjustment.

[0031] Figure 10 This is a schematic diagram of the overall structure of a confocal microscope.

[0032] In the figure, 1. optical fiber bundle; 2. coupled objective lens group; 3. objective lens connecting sleeve; 31. objective lens positioning part; 32. optical fiber connecting part; 4. objective lens end cover; 5. proximal ferrule; 6. proximal end of plug; 61. connecting sleeve positioning part; 62. ferrule connecting part; 7. handle plug; 71. miniature objective lens; L1. first lens; L2. second lens; L3. third lens; L4. fourth lens; L5. fifth lens; L6. sixth lens; 8. confocal host; 81. laser; 82. beam expander group; 83. dichroic mirror; 84. two-position scanning mechanism; 85. relay lens group; 86. pinhole lens; 87. detector; 9. observation tooling; 91. tube mirror; 92. camera. DETAILED DESCRIPTION

[0033] 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 with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining 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 may be combined with each other as long as they do not conflict with each other.

[0034] like Figure 1As shown, the present invention proposes a confocal probe catheter, including an optical fiber bundle 1, a coupled objective lens group 2 and an objective lens connecting sleeve 3. The objective lens connecting sleeve 3 includes an objective lens positioning portion 31 and an optical fiber connecting portion 32. The interiors of the objective lens positioning portion 31 and the optical fiber connecting portion 32 are hollow and coaxial. The coupled objective lens group 2 is arranged in the objective lens positioning portion 31, and the proximal end of the optical fiber bundle 1 is arranged in the optical fiber connecting portion 32.

[0035] Placing the coupled objective lens assembly 2 within the objective lens positioning portion 31 and the optical fiber bundle 1 within the optical fiber connection portion 32 ensures that the coupled objective lens assembly 2 and the optical fiber bundle 1 are concentric after installation. Focusing the optical fiber bundle 1 and the coupled objective lens assembly 2 can be achieved by simply adjusting the distance between the coupled objective lens assembly 2 and the optical fiber bundle 1 in the axial direction. After focusing, the positions of the two are fixed to form a confocal probe catheter, which can be directly docked with the confocal mainframe for use without the need for focusing. During clinical use, focusing time can be reduced by 2-3 minutes per examination, effectively shortening the duration of confocal endoscopic examinations.

[0036] Furthermore, the existing confocal probe is composed of a distal miniature objective lens 71, an optical fiber bundle 1, a proximal handle, and a handle plug 7. The distal miniature objective lens 71 enters the human body along the clamp channel of an ordinary endoscope, and the coupling objective lens group 2 at the interface of the confocal host focuses the excitation light inside the confocal host onto the end face of the optical fiber bundle 1 at the axis of the end face of the confocal probe inserted into the optical fiber connector. The plugging and unplugging of the confocal probe realizes the coupling and disconnection of the optical system. In conventional designs, the coupling objective lens group 2 is arranged in the confocal host and optically coupled with the confocal probe. Since the coupling accuracy of the coupling objective lens group 2 is extremely high, reaching the micron level requirement, in order to adapt to confocal probes produced in batches and with low consistency, a focusing adjustment mechanism for the coupling objective lens group 2 is provided in the confocal host. By adjusting the position of the coupling objective lens group 2, different batches of confocal probes with the same interface can be adapted. The confocal probe catheter of the present invention assembles the coupling objective lens group 2 and the optical fiber bundle 1 together, separates the coupling objective lens group 2 from the confocal host, and designs it on the confocal probe. Therefore, when replacing different batches of confocal probes, the present invention does not require repeated focusing, which can greatly improve inspection efficiency and enhance operating experience.

[0037] Furthermore, existing confocal probes and confocal scanners typically use a full-stroke scanning method to align the focus, identifying the clearest image location for positioning. This full-stroke scanning and identification process consumes considerable time, and accidentally touching the confocal probe during the identification scan will result in scan failure. The confocal probe catheter of the present invention eliminates the need for this focusing process during use, effectively avoiding increased inspection time due to focus failures.

[0038] Furthermore, if Figure 2As shown, the confocal probe catheter also includes an objective lens end cover 4, which is arranged at the end of the objective lens positioning part 31 away from the optical fiber connection part 32, and glue is filled between the objective lens end cover 4, the coupling objective lens group 2 and the objective lens connecting sleeve 3.

[0039] Specifically, the objective lens end cap 4 and the end of the objective lens connecting sleeve 3 can be connected and fixed by means of a threaded pair, an interference fit, a clearance fit, or the like. Glue is then filled during the connection, and after the glue solidifies, it provides a sealing effect, thereby protecting the coupled objective lens assembly 2 within. After the objective lens end cap 4 is connected and fixed to the end of the objective lens connecting sleeve 3, the most convex point of the lens in the coupled objective lens assembly 2 closest to the objective lens end cap 4 should be slightly lower than the surface of the objective lens end cap 4, thereby preventing accidental scratches and facilitating cleaning of the outer surface of the lens.

[0040] Furthermore, if Figure 3 As shown, the confocal probe catheter further includes a proximal ferrule 5 , in which the proximal end of the optical fiber bundle 1 is disposed, and the proximal ferrule 5 is disposed within the optical fiber connecting portion 32 .

[0041] The proximal ferrule 5 is coated on the proximal side of the optical fiber bundle 1, and the optical fiber bundle 1 can be positioned and provided with a hard shell. During the positioning process, the proximal ferrule 5 only needs to be connected and fixed with the optical fiber connector 32 to fix the proximal end of the optical fiber bundle 1. Specifically, when the proximal end of the optical fiber bundle 1 is inserted into the proximal ferrule 5, the circumferential side can be smeared with glue for filling. After the glue is cured, the position of the optical fiber bundle 1 and the proximal ferrule 5 can be fixed, and a waterproof effect can be achieved at the same time. The optical fiber connector 32 of the objective lens connecting sleeve 3 is hollow, and the proximal ferrule 5 carries the proximal end of the optical fiber bundle 1 and is inserted here. By the coaxial arrangement of the optical fiber connector 32 and the objective lens positioning portion 31, the coaxial positioning of the optical fiber bundle 1 and the coupled objective lens group 2 can be achieved. The proximal ferrule 5 and the inside of the optical fiber connecting part 32 can be connected and fixed by a threaded pair. By adjusting the distance between the proximal ferrule 5 and the coupling objective lens group 2 in the axial direction, the spacing between the end face of the optical fiber bundle 1 and the coupling objective lens group 2 can be adjusted to achieve the clearest end face imaging.

[0042] Furthermore, if Figure 4 As shown, the confocal probe catheter also includes a proximal plug end 6, which includes a connecting sleeve positioning portion 61 and a ferrule connecting portion 62. The interiors of the connecting sleeve positioning portion 61 and the ferrule connecting portion 62 are hollow, the objective lens connecting sleeve 3 is arranged in the connecting sleeve positioning portion 61, and the proximal ferrule 5 is arranged in the ferrule connecting portion 62.

[0043] The outer diameter and length of the proximal end 6 of the plug conform to the interface standards with the confocal mainframe. The proximal ferrule 5 and the exterior of the objective lens connection sleeve 3 are connected to the confocal mainframe via the proximal end 6 of the plug. Specifically, the portion of the proximal ferrule 5 located outside the objective lens connection sleeve 3 is connected to the ferrule connection portion 62 via a threaded pair. Before connection, glue can be applied to the threads of the two for sealing and securing. The objective lens connection sleeve 3 and the connection sleeve positioning portion 61 can be connected and secured by a threaded pair, an interference fit, a clearance fit, or the like. Glue is applied to the contact surface of the two for curing and sealing. The end faces of the two ends away from the optical fiber bundle 1 are flush.

[0044] More specifically, the outer diameter of the connecting sleeve positioning portion 61 of the proximal end of the plug 6 is larger than the outer diameter of the ferrule connecting portion 62, so a limiting step is formed at the connection between the two. The outer diameter of the ferrule connecting portion 62 can be provided with an external thread, which is threadedly connected to the existing confocal probe handle plug 7, and the outer part of the connecting sleeve positioning portion 61 is connected to the interface of the confocal host.

[0045] like Figure 5 and Figure 6 As shown, the confocal probe catheter of the present invention is based on the existing confocal probe, and a proximal ferrule 5, an objective lens connection sleeve 3, a coupling objective lens group 2 and a proximal plug 6 are added to the proximal end of the optical fiber bundle 1. Then, one end of the proximal plug 6 is connected to the handle plug 7. Before connection, Figure 5 As shown, after connection Figure 6 As shown, the other end is connected to the confocal mainframe, which is a minor improvement to the existing confocal probe structure. At the same time, the proximal ferrule 5 and the objective lens connecting sleeve 3 integrate the coupling objective lens group 2 with the optical fiber bundle 1, thereby avoiding the focusing process between the confocal probe and the confocal mainframe.

[0046] Furthermore, if Figure 7 and Figure 8 As shown, the coupling objective lens assembly 2 includes a fifth lens L5, a fourth lens L4, a third lens L3, a second lens L2, and a first lens L1, which are arranged in sequence along the optical axis from the objective lens end cover 4 to the optical fiber bundle 1.

[0047] On the optical axis, the direction toward the objective lens end cap 4 is the image side, and the direction toward the optical fiber bundle 1 is the object side. Light emitted from the object side passes through the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 in sequence before reaching the image side for imaging. Through the coordination of these lenses, the numerical aperture is matched to that of the optical fiber bundle 1 while maintaining a large working distance.

[0048] In some embodiments, as Figure 7As shown, the fifth lens L5 has a convex surface facing the image side and a concave surface facing the object side, the fourth lens L4 has a concave surface facing the image side and a convex surface facing the object side, the third lens L3 has a flat surface facing the image side and a convex surface facing the object side, the second lens L2 has a convex surface facing the image side and a flat surface facing the object side, and the first lens L1 has a concave surface facing the image side and a convex surface facing the object side.

[0049] In other embodiments, the fifth lens L5 has a convex surface facing the image side and a convex surface facing the object side, the fourth lens L4 has a concave surface facing the image side and a convex surface facing the object side, the third lens L3 has a flat surface facing the image side and a convex surface facing the object side, the second lens L2 has a convex surface facing the image side and a flat surface facing the object side, and the first lens L1 has a concave surface facing the image side and a convex surface facing the object side. A sixth lens L6 may further be provided on the side of the fifth lens L5 away from the fourth lens L4. Figure 8 As shown, both sides of the sixth lens L6 are planes.

[0050] The total optical length of the coupled objective lens group 2 is TTL, 13.5 mm < TTL < 17.3 mm, and the maximum outer diameter is BD, 2.79 mm < BD < 2.94 mm.

[0051] Because the confocal probe must pass through narrow human cavities, its outer diameter is very small. The diameter of the confocal probe handle is also relatively small, typically less than 3 mm. The coupled objective lens assembly designed in this utility model has a maximum outer diameter of no more than 2.94 mm and a total optical length of no more than 17.3 mm. Compared to the coupled objective lens assembly in existing confocal microendoscopes, it has a smaller mechanical outer diameter and shorter length. Therefore, the coupled objective lens assembly can be more easily assembled into the proximal end 6 of the handle plug 7, achieving a "plug and play" effect, and obtaining clear, high-contrast images without the need for focusing.

[0052] Furthermore, the numerical aperture (NA) of coupled objective lens assembly 2 is 0.35. This NA ensures clear cell imaging with the confocal endoscope. The focal length (f) is 6.7 mm. This focal length ensures a sufficient field of view for cell imaging. The back focus distance (BL) is 3.45 mm < BL < 3.68 mm. The design wavelengths of coupled objective lens assembly 2 are 488 nm, 520 nm, and 550 nm. The coordination of the back focus distance and focal length improves imaging quality.

[0053] Furthermore, 0.810<(D1+D2) / (D1+D2+D12)<0.850, where D1 represents the center thickness of the first lens L1, D2 represents the center thickness of the second lens L2, and D12 represents the center thickness between two adjacent surfaces of the first lens L1 and the second lens L2.

[0054] The first lens L1 and the second lens L2 are the first two lenses that light passes through during the imaging process. By allocating and designing the parameters of these two lenses, the incident angle of light can be controlled. By limiting the center thickness of the two lenses, the shape of the lenses can be reasonably controlled, thereby achieving the best imaging effect with the shortest possible length.

[0055] 0.812<(R51+R52)×|r51 / r52| / D5<1.332, where R51 represents the clear semi-aperture of the image-side surface of the fifth lens element L5, R52 represents the clear semi-aperture of the object-side surface of the fifth lens element L5, r51 represents the curvature radius of the image-side surface of the fifth lens element L5, r52 represents the curvature radius of the object-side surface of the fifth lens element L5, and D5 represents the center thickness of the fifth lens element L5.

[0056] By designing the above-mentioned parameter allocation for the fifth lens L5, the emission angle of the light can be controlled, and the field curvature and phase difference can be well converged, distortion can be reduced, and the imaging quality of the miniature coupling objective lens group can be improved. At the same time, in combination with other lens parameters, the smallest possible mechanical outer diameter can be achieved while ensuring optimal light performance, so that the coupling objective lens has a miniature effect and can be combined with a miniature-sized confocal probe.

[0057] More specifically, in some embodiments, the coupling objective lens group 2 provided is as follows Figure 7 As shown, the fifth lens L5 has a convex surface facing the image side and a concave surface facing the object side. Specific parameters of each lens are detailed in Table 1.

[0058] Table 1

[0059]

[0060] In this embodiment, surface number 1 is the image surface, and surface number 12 is the object surface.

[0061] The center thickness of the fifth lens element L5 between its image-side surface and the image plane is 0.500mm. The radius of curvature of its image-side surface is 9.128mm, with a clear semi-aperture of 2.55mm. The radius of curvature of its object-side surface is 39.178mm, with a clear semi-aperture of 2.45mm. The fifth lens element L5 is made of SAPPHIRE and has a center thickness of 1.399mm. The center thickness between the adjacent surfaces of the fifth lens element L5 and the fourth lens element L4 is 1.675mm.

[0062] The image-side radius of curvature of the fourth lens element, L4, is -4.970mm, with a clear semi-aperture of 2.33mm. The object-side radius of curvature is -12.011mm, with a clear semi-aperture of 2.60mm. The fourth lens element, L4, is made of H-ZF73 and has a center thickness of 1.056mm. The center thickness between the adjacent surfaces of the fourth lens element, L4, and the third lens element, L3, is 0.500mm.

[0063] The image-side surface of the third lens element, L3, is flat with an infinite radius of curvature and a clear semi-aperture of 2.75mm. The object-side surface has a radius of curvature of -7.057mm and a clear semi-aperture of 2.84mm. The third lens element, L3, is made of H-ZLAF68N and has a center thickness of 1.645mm. The center thickness between the adjacent surfaces of the third lens element, L3, and the second lens element, L2, is 0.500mm.

[0064] The image-side surface of the second lens element, L2, has a radius of curvature of 7.795mm and a clear semi-aperture of 2.50mm. The object-side surface is flat, with an infinite radius of curvature and a clear semi-aperture of 2.18mm. The material of the second lens element, L2, is H-LAK52, with a center thickness of 1.565mm. The center thickness between the adjacent surfaces of the second lens element, L2, and the first lens element, L1, is 0.549mm.

[0065] The image-side radius of curvature of the first lens element L1 is -6.971mm, with a clear semi-aperture of 2.06mm. The object-side radius of curvature is -10.829mm, with a clear semi-aperture of 1.87mm. The material of the first lens element L1 is H-BAK7, with a center thickness of 1.000mm. The center thickness between the object-side surface and the object plane is 3.601mm.

[0066] In this embodiment, among the surface numbers 2-11, except for the plane, all other surfaces are spherical surfaces.

[0067] The field of view diameter of the coupled objective lens group is 0.4mm, the total optical length TTL is 14mm, the maximum outer diameter is 2.84mm, and the mechanical back focus is 3.6mm.

[0068] According to Table 1, D1 = 1.000 mm, D2 = 1.565 mm, D12 = 0.549 mm, and (D1 + D2) / (D1 + D2 + D12) = 0.824.

[0069] R51=2.55mm, R52=2.45mm, r51=9.128mm, r52=39.178mm, D5=1.399mm, (R51+R52)×|r51 / r52| / D5=0.833.

[0070] In this embodiment, the RMS radius of the diffuse spot is less than 1.0 μm across the entire field of view, significantly smaller than the 3.5 μm core pitch of the fiber bundle used with it. This maximizes optical signal coupling efficiency and increases the contrast of the confocal image. Furthermore, the field area is fully corrected and less than 10 μm across the entire field of view. Distortion is less than 0.2%, less than 5% of the human eye's discernible value, demonstrating excellent imaging performance. Axial chromatic aberration within the design wavelength range is less than 3.034 μm, demonstrating that the coupled objective assembly is fully corrected for chromatic aberration.

[0071] In other embodiments, the coupling objective lens group 2 provided is as follows: Figure 8 As shown, the fifth lens element L5 has a convex surface facing the image side and a convex surface facing the object side. A sixth lens element L6 is positioned between the fifth lens element L5 and the image side. Both surfaces of the sixth lens element L6 are flat and made of glass, primarily for physical protection. An antireflection coating can also be applied to the object-facing side of the sixth lens element L6 to reduce the transmittance of laser and fluorescent light during imaging, while also providing corrosion and high-temperature resistance. Specific parameters for each lens element are detailed in Table 2.

[0072] Table 2

[0073]

[0074]

[0075] In this embodiment, surface number 1 is the image surface, and surface number 14 is the object surface.

[0076] The center thickness between the image-side surface and the image plane of the sixth lens element L6 is 0.500mm. The image-side surface of the sixth lens element L6 is flat with an infinite radius of curvature and a clear semi-aperture of 2.60mm. The object-side surface of the sixth lens element L6 is flat with an infinite radius of curvature and a clear semi-aperture of 2.60mm. The material of the sixth lens element L6 is SAPPHIRE, and the center thickness is 1.000mm. The center thickness between the adjacent surfaces of the sixth lens element L6 and the fifth lens element L5 is 0.500mm.

[0077] The image-side surface of the fifth lens element, L5, has a radius of curvature of 14.585mm and a clear semi-aperture of 2.58mm. The object-side surface has a radius of curvature of -39.612mm and a clear semi-aperture of 2.52mm. The fifth lens element, L5, is made of H-ZLAF68N and has a center thickness of 1.444mm. The center thickness between the adjacent surfaces of the fifth lens element, L5, and the fourth lens element, L4, is 1.861mm.

[0078] The image-side surface of the fourth lens element, L4, has a radius of curvature of -5.391mm and a clear semi-aperture of 2.29mm. The object-side surface has a radius of curvature of -30.821mm and a clear semi-aperture of 2.67mm. The fourth lens element, L4, is made of H-ZF73 and has a center thickness of 2.146mm. The center thickness between the adjacent surfaces of the fourth lens element, L4, and the third lens element, L3, is 0.500mm.

[0079] The image-side surface of the third lens element, L3, is flat with an infinite radius of curvature and a clear semi-aperture of 2.81mm. The object-side surface has a radius of curvature of -7.252mm and a clear semi-aperture of 2.94mm. The third lens element, L3, is made of H-ZLAF68N and has a center thickness of 1.714mm. The center thickness between the adjacent surfaces of the third lens element, L3, and the second lens element, L2, is 0.753mm.

[0080] The image-side surface of the second lens element, L2, has a radius of curvature of 7.303mm and a clear semi-aperture of 2.59mm. The object-side surface is flat, with an infinite radius of curvature and a clear semi-aperture of 2.24mm. The material of the second lens element, L2, is H-LAK52, with a center thickness of 1.797mm. The center thickness between the adjacent surfaces of the second lens element, L2, and the first lens element, L1, is 0.547mm.

[0081] The image-side surface of the first lens L1 has a radius of curvature of -7.423mm and a clear semi-aperture of 2.12mm. The object-side surface has a radius of curvature of -9.545mm and a clear semi-aperture of 1.94mm. The first lens L1 is made of H-BAK7 and has a center thickness of 1.000mm. The center thickness between the object surface and the object plane is 3.516mm.

[0082] In this embodiment, among the surface numbers 2-11, except for the plane, all other surfaces are spherical surfaces.

[0083] The field diameter of the coupled objective lens group is 0.4mm, the total optical length TTL does not exceed 17.3mm, the maximum outer diameter does not exceed 2.94mm, and the mechanical back focus is 3.5mm.

[0084] According to Table 2, D1 = 1.000 mm, D2 = 1.797 mm, D12 = 0.547 mm, and (D1 + D2) / (D1 + D2 + D12) = 0.836.

[0085] R51=2.58mm, R52=2.52mm, r51=14.585mm, r52=-39.612mm, D5=1.444mm, (R51+R52)×|r51 / r52| / D5=1.300.

[0086] In this embodiment, the RMS radius of the diffuse spot is less than 1.0 μm across the entire field of view, significantly smaller than the 3.5 μm core pitch of the fiber bundle used with it. This maximizes optical signal coupling efficiency and increases the contrast of the confocal image. Furthermore, the field area is fully corrected and less than 10 μm across the entire field of view. Distortion is less than 0.2%, less than 5% discernible by the human eye, demonstrating excellent imaging performance. Axial chromatic aberration within the design wavelength range is 4.0848 μm, slightly larger than the diffraction limit of 3.696 μm, demonstrating that the coupled objective assembly is fully corrected for chromatic aberration.

[0087] Multiple spacers are located within the objective lens positioning portion 31. The outer diameter of these spacers is consistent with the outer diameter of each lens in the coupled objective lens. These spacers are hollow, annular structures. Each lens in the coupled objective lens assembly 2 is connected to the spacers via threaded connections, interference fits, clearance fits, or other methods. These spacers help position the distance between the lenses while not blocking light passing through the coupled objective lens assembly 2.

[0088] The present invention also proposes a method for assembling and adjusting a confocal probe catheter, such as Figure 9 As shown in (a) and (b), the following steps are included:

[0089] S1, make the observation tool 9, the coupling objective lens group 2, and the optical fiber bundle 1 coaxial, and the observation tool 9 includes a tube lens 91 and a camera 92;

[0090] S2: Move the coupled objective lens group 2 and the optical fiber bundle 1 relative to each other, and observe the imaging result of the camera 92 until the clarity of the imaging result is optimal. Then, fix the coupled objective lens group 2 and the optical fiber bundle 1 so that their relative positions do not change. The confocal probe catheter is installed and adjusted.

[0091] The coupling objective lens group 2 is installed in the objective lens positioning part 31, and the optical fiber bundle 1 is inserted into the optical fiber connecting part 32 through the proximal core 5. The coupling objective lens group 2 and the optical fiber bundle 1 can be coaxial. On the axis, observation is performed through the tube lens 91 and the camera 92. While observing the imaging results, the distance between the coupling objective lens and the optical fiber bundle 1 is adjusted to obtain the distance between the two when the clarity is best. Finally, the positions of the two are fixed, and the obtained confocal probe catheter can perform clear confocal imaging.

[0092] In order to further explain the use of tooling, Figure 7 The coupling objective lens in the paper is further explained in detail. Theoretically, Figure 7The distance between the first lens L1 and the object plane, that is, the distance between the two surfaces numbered 11 and 12 in Table 1, is the distance between the coupled objective lens assembly 2 and the optical fiber bundle 1 after they are assembled. However, in practice, the shape and optical path of the first lens L1 are affected by many factors and may deviate from the theoretical value. Therefore, it is still necessary to rely on the observation tool 9 to perform fine adjustments to obtain the position with the clearest image. In other words, the distance between the coupled objective lens assembly 2 and the optical fiber bundle 1 is adjusted through the installation and adjustment method of the present invention.

[0093] Specifically, during actual adjustment, it is only necessary to adjust the relative position of the coupling objective lens group 2 and the optical fiber bundle 1. This embodiment is explained by taking the change of the position of the coupling objective lens group 2 as an example. The coupling objective lens group 2 is installed in the objective lens positioning portion 31, and the optical fiber bundle 1 is installed in the proximal ferrule 5. The optical fiber bundle 1 is flush with the end of the proximal ferrule 5 close to the coupling objective lens group 2; the objective lens positioning portion 31 and the proximal ferrule 5 are respectively installed at both ends of the proximal end 6 of the plug, and then the position of the observation tool 9 is set according to S1. The proximal ferrule 5 can be matched with the ferrule connection portion 62 and the optical fiber connection portion 32 in a threaded manner and filled with glue. The relative position of the optical fiber bundle 1 and the coupling objective lens group 2 is adjusted by rotating the proximal end 6 of the plug. When the camera 92 obtains the clearest image, the focusing of the coupling objective lens group 2 and the optical fiber bundle 1 is completed. Stop rotating the proximal end 6 of the plug. At this time, the glue at the threaded connection fixes the relative position of the coupling objective lens group 2 and the optical fiber bundle 1 due to solidification, and there is no need to focus again during subsequent use. Figure 9 (a) shows the positional relationship between the observation tool 9, the optical fiber bundle 1, and the coupling objective lens group 2 before assembly. The distance between the coupling objective lens group 2 and the optical fiber bundle 1 will change during the assembly process. When the camera 92 obtains the clearest image, the coupling objective lens group 2 is assembled and adjusted. The position between the coupling objective lens group 2 and the optical fiber bundle 1 is as shown in FIG. Figure 9 (b) shown.

[0094] In some embodiments, the coupling objective lens group 2 and the optical fiber bundle 1 move relative to each other in a step-by-step manner. The parameter for determining the clarity of the imaging result is the image resolution. Taking the step distance of the coupling objective lens group 2 as 1 mm as an example, each time the coupling objective lens group 2 moves 1 mm, the camera 92 obtains an imaging result. During this process, the clarity of the imaging result will gradually increase until it reaches the optimal value, and then begin to decline. When the clarity of the imaging result obtained by the camera 92 begins to decline, the coupling objective lens group 2 is returned to the previous position. At this time, the distance between the coupling objective lens group 2 and the optical fiber bundle 1 is the distance at which the imaging is clearest. By fixing the position of the coupling objective lens group 2 at this position, a confocal probe catheter can be obtained.

[0095] During the movement of the coupled objective lens assembly 2, the distance between it and the observation fixture 9 increases, while the distance between it and the optical fiber bundle 1 decreases. Because collimated light is transmitted between the tube lens 91 and the coupled objective lens assembly 2, the increased distance between them does not affect imaging. Consequently, the coupled objective lens assembly 2 ultimately positions the proximal end face of the optical fiber bundle 1 on the object plane of the coupled objective lens assembly 2, ultimately resulting in a clear image on the detection surface of the camera 92. When the confocal probe catheter is docked with the confocal mainframe 8, scanning focus is no longer required.

[0096] The present invention also provides a confocal microscope imager, such as Figure 10 As shown, the confocal system comprises a confocal mainframe 8 and the aforementioned confocal probe catheter. The confocal mainframe 8 includes a housing and, within the housing, a laser 81, a beam expander lens assembly 82, a dichroic mirror 83, a two-position scanning mechanism 84, a relay lens assembly 85, a pinhole lens 86, and a detector 87. A probe connection mechanism is provided on one side of the housing, into which the confocal probe catheter is secured.

[0097] Compared to the prior art, the confocal mainframe 8 of the present invention omits the coupling objective lens assembly 2, which is instead integrated into the confocal probe, forming a confocal probe conduit. The spacing between the coupling objective lens assembly 2 and the fiber bundle 1 is adjusted using the aforementioned adjustment method to achieve the clearest imaging spacing. The resulting confocal probe conduit can be used directly with the confocal mainframe 8, eliminating the need for focusing, thereby effectively reducing confocal inspection time.

[0098] Furthermore, compared with the existing confocal microscope, since there is no need for focusing, the structure in the probe connection mechanism that plays a focusing role can be removed, thereby simplifying the existing probe connection mechanism.

[0099] Furthermore, the confocal microscope also includes a micro-objective lens 71 located at the distal end of the optical fiber bundle 1. The micro-objective lens 71 can be a gradient refractive index lens or a dedicated lens optimized for specific usage scenarios, such as the type of fluorescent dye and different departments. Depending on the diameter of the cavity in the application scenario, micro-objective lenses 71 of different diameters are selected. In some application scenarios, the bare optical fiber bundle 1 can be used directly for imaging without the micro-objective lens 71. The confocal microscope of the present invention can be applied to application scenarios including the gallbladder and pancreas, lungs, digestive tract, and heart.

[0100] It is easy for those skilled in the art to understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A confocal probe catheter, characterized in that: It includes an optical fiber bundle, a coupled objective lens group and an objective lens connecting sleeve. The objective lens connecting sleeve includes an objective lens positioning part and an optical fiber connecting part. The interiors of the objective lens positioning part and the optical fiber connecting part are hollow and coaxial. The coupled objective lens group is arranged in the objective lens positioning part, and the proximal end of the optical fiber bundle is arranged in the optical fiber connecting part.

2. The confocal probe catheter according to claim 1, characterized in that: The confocal probe catheter further includes an objective lens end cap, which is arranged at an end of the objective lens positioning portion away from the optical fiber connection portion. Glue is filled between the objective lens end cap, the coupling objective lens group, and the objective lens connection sleeve.

3. The confocal probe catheter according to claim 2, characterized in that: The confocal probe catheter further includes a proximal ferrule, the proximal end of the optical fiber bundle is arranged in the proximal ferrule, and the proximal ferrule is arranged in the optical fiber connecting portion.

4. The confocal probe catheter according to claim 3, characterized in that: The confocal probe catheter also includes a proximal end of a plug, which includes a connecting sleeve positioning portion and a ferrule connecting portion. The interiors of the connecting sleeve positioning portion and the ferrule connecting portion are hollow. The objective lens connecting sleeve is arranged in the connecting sleeve positioning portion, and the proximal ferrule is arranged in the ferrule connecting portion.

5. The confocal probe catheter according to claim 2, characterized in that: On the optical axis, the side facing the objective lens end cap is the image side, and the side facing the optical fiber bundle is the object side. The coupled objective lens group includes a fifth lens, a fourth lens, a third lens, a second lens, and a first lens arranged in sequence along the optical axis from the objective lens end cap to the optical fiber bundle. The first lens has a concave surface facing the image side, and a convex surface facing the object side. The second lens has a convex surface facing the image side, and a flat surface facing the object side. The third lens has a flat surface facing the image side, and a convex surface facing the object side. The fourth lens has a concave surface facing the image side, and a convex surface facing the object side. The fifth lens has a convex surface facing the image side, and a concave or convex surface facing the object side.

6. The confocal probe catheter according to claim 5, characterized in that: The total optical length of the coupled objective lens group is TTL, 13.5 mm < TTL < 17.3 mm, and the maximum outer diameter is BD, 2.79 mm < BD < 2.94 mm.

7. The confocal probe catheter according to claim 6, characterized in that: When the surface of the fifth lens facing the object side is convex, a sixth lens is further provided between the fifth lens and the image side, and both surfaces of the sixth lens are planes.

8. A confocal microscope, characterized in that: The confocal mainframe comprises a confocal mainframe and a confocal probe catheter as described in any one of claims 1 to 6, wherein the confocal mainframe comprises a housing and a laser, a beam expander lens group, a dichroic mirror, a two-position scanning mechanism, a relay lens group, a pinhole lens, and a detector inside the housing; a probe connecting mechanism is provided on one side of the housing, and the confocal probe catheter is fixed in the probe connecting mechanism.

9. The confocal microscope according to claim 8, characterized in that: Also included is a miniature objective lens located at the distal end of the optical fiber bundle.

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