CN117084628A

CN117084628A - Multifocal multi-modality imaging catheter

Info

Publication number: CN117084628A
Application number: CN202210510632.7A
Authority: CN
Inventors: 朱锐
Original assignee: SHENZHEN VIVOLIGHT MEDICAL DEVICE & TECHNOLOGY CO LTD
Current assignee: SHENZHEN VIVOLIGHT MEDICAL DEVICE & TECHNOLOGY CO LTD
Priority date: 2022-05-11
Filing date: 2022-05-11
Publication date: 2023-11-21

Abstract

The application is applicable to the technical field of medical appliances, and provides a multi-focus multi-mode imaging catheter, which comprises: the catheter body and the lens component arranged in the inner cavity of the catheter body, the lens component comprises a coaxial component and a non-coaxial component connected with the coaxial component, the coaxial component is used for receiving excitation light provided by a host system and transmitting the excitation light to the non-coaxial component, the non-coaxial component can separate the excitation light into first OCT laser and first autofluorescence laser, the first OCT laser forms a first focus, the first autofluorescence laser forms a second focus to act on detected tissues, the detected tissues are excited to emit second OCT laser and second autofluorescence laser, the second OCT laser and the second autofluorescence laser are emitted to the host system through the lens component, different characteristic requirements of OCT imaging and autofluorescence imaging are met, and therefore imaging quality, accuracy, image acquisition time, sensitivity and the like are relatively high.

Description

Multifocal multi-modality imaging catheter

Technical Field

The application belongs to the technical field of medical appliances, and particularly relates to a multi-focus multi-mode imaging catheter.

Background

Optical coherence tomography (Optical Coherence Tomography, OCT) is a biomedical optical imaging technology, the resolution of OCT is extremely high, the axial resolution of OCT can reach about 10 mu m, the OCT has tissue distinguishing capability, namely, the main components and histological characteristics of plaques and different plaque components, such as common fibrous plaques, lipid plaques and calcified plaques in coronary arteries, can be basically known through OCT images, and different signal characteristics are presented under the OCT images, so that clinicians with abundant image reading experience can identify the types of the plaques according to the different signal characteristics on the images, and the OCT has important significance for diagnosing and selecting treatment schemes of coronary heart diseases. However, OCT still has limitations, OCT cannot recognize IPH, and intravascular expanded bleeding (IPH, intraplaque hemorrhages) is one of the features of high-risk atherosclerotic plaques, playing a key role in the progression of atherosclerotic disease. Current studies indicate that tissue autofluorescence (NIRAF, near-infrared autofluorescence) can detect IPH. However, intravascular NIRAF often lacks depth information, and the inability to distinguish and locate lipids is also one of the most critical features of plaque. Thus, OCT and NIRAF binding can be complemented for optimal effect.

Disclosure of Invention

The embodiment of the application aims to provide a multi-focus multi-mode imaging catheter, which aims to solve the technical problem that the requirements of different characteristics of OCT imaging and autofluorescence imaging cannot be met simultaneously in the prior art.

To achieve the above object, according to one aspect of the present application, there is provided a multi-focal multi-modality imaging catheter comprising: the pipe body with set up in the camera lens subassembly of pipe body inner chamber, the camera lens subassembly includes: the coaxial assembly is used for receiving excitation light provided by the host system and transmitting the excitation light to the non-coaxial assembly, the non-coaxial assembly can separate the excitation light into first OCT laser and first autofluorescence laser, the first OCT laser forms a first focus, the first autofluorescence laser forms a second focus to act on detected tissues, the detected tissues are excited to emit second OCT laser and second autofluorescence laser, and the second OCT laser and the second autofluorescence laser return to the host system through the lens assembly.

Optionally, the non-coaxial assembly comprises: the coaxial assembly, the first optical transmission assembly and the second optical transmission assembly are sequentially connected; the second optical transmission assembly comprises a first focusing unit and a second focusing unit, wherein the first focusing unit is arranged on the emergent path of the first OCT laser, so that the first OCT laser forms a first focus through the first focusing unit; the second focusing unit is arranged on the emergent path of the first self-fluorescence laser, so that the first self-fluorescence laser forms a second focus through the second focusing unit.

Optionally, the first optical transmission assembly includes a first lens unit and a second lens unit, and the first lens unit and the second lens unit are disposed at intervals; the first lens unit is disposed at an output end of the coaxial assembly, and the first lens unit includes: a first lens and a second lens, the first lens being disposed on a transmission path of the first OCT laser light so that the first OCT laser light refracted by the first lens is parallel to each other; the second lens is arranged on a first transmission path of the first self-fluorescence laser, and the first self-fluorescence laser refracted by the second lens is parallel to each other; the second lens unit comprises a third lens and a fourth lens, the third lens is positioned on one side of the first lens away from the coaxial assembly and is used for receiving the first OCT laser refracted by the first lens and transmitting the first OCT laser to the first focusing unit; the fourth lens is positioned at one side of the second lens far away from the coaxial assembly and is used for receiving the first self-fluorescence laser refracted by the second lens and transmitting the first self-fluorescence laser to the second focusing unit;

the first lens unit further includes: the fifth lens is positioned on the second transmission path of the first self-fluorescence laser, so that the first self-fluorescence laser refracted by the fifth lens is parallel to each other, and the fourth lens is also positioned on one side of the fifth lens far away from the coaxial assembly and is used for receiving the first self-fluorescence laser refracted by the fifth lens and transmitting the first self-fluorescence laser to the second focusing unit; the first lens, the second lens and the fifth lens are arranged along the radial direction of the coaxial assembly, and the first lens is arranged between the second lens and the fifth lens.

Optionally, the first optical transmission assembly further includes a first fixing member, two ends of the first fixing member are respectively connected with the first lens unit and the second lens unit, and the first fixing member can transmit the first OCT laser light and the first autofluorescence laser light after being refracted by the first lens unit to the second lens unit.

Optionally, the first light transmission component comprises a sixth lens and a dichroic mirror, the sixth lens is connected with the output end of the coaxial component, so that the first OCT laser light and the first autofluorescence laser light after being refracted by the sixth lens are emitted to the dichroic mirror in parallel; the dichroic mirror is arranged on one side of the sixth lens away from the coaxial assembly, is positioned between the first focusing unit and the second focusing unit, and is used for transmitting the first OCT laser refracted by the sixth lens and transmitting the first OCT laser to the first focusing unit, and reflecting the first autofluorescence laser refracted by the sixth lens and transmitting the first autofluorescence laser to the second focusing unit.

Optionally, the first light transmission assembly further includes a second fixing piece and a third fixing piece, the second fixing piece is connected with the dichroic mirror and the first focusing unit respectively, the dichroic mirror is further connected with the second focusing unit, and the third fixing piece is connected with the sixth lens and the second focusing unit respectively.

Optionally, the coaxial assembly includes a double-clad optical fiber and a coreless optical fiber, the coreless optical fiber is connected between the double-clad optical fiber and the non-coaxial assembly, the double-clad optical fiber includes a fiber core, an inner cladding sleeved on the fiber core, and an outer cladding sleeved on the inner cladding, the first OCT laser is transmitted through the fiber core, and the first autofluorescence laser is transmitted through the inner cladding.

Optionally, the coaxial assembly includes a fusion optical fiber, the fusion optical fiber has an optical fiber separation section, the first optical transmission assembly includes a single-mode optical fiber, a multimode optical fiber, a first amplifying lens and a second amplifying lens, an input end of the single-mode optical fiber and an input end of the multimode optical fiber are respectively connected with the optical fiber separation section, an output end of the single-mode optical fiber, the first amplifying lens and the first focusing unit are sequentially connected, and an output end of the multimode optical fiber, the second amplifying lens and the second focusing unit are sequentially connected; the fusion optical fiber comprises a single-mode optical fiber core, a multimode optical fiber cladding sleeved on the single-mode optical fiber core and a multimode optical fiber coating sleeved on the multimode optical fiber cladding, wherein the first OCT laser is transmitted from the single-mode optical fiber core, and the first self-fluorescence laser is transmitted from the multimode optical fiber cladding.

Optionally, a fourth fixing piece is connected between the first magnifying lens and the first focusing unit, and the fourth fixing piece can transmit the first OCT laser to the first focusing unit; a fifth fixing piece is connected between the second amplifying lens and the second focusing unit and can transmit the first self-fluorescence laser to the second focusing unit.

Optionally, the first focusing unit includes a first hemispherical lens, and the second focusing unit includes a second hemispherical lens.

The multi-mode imaging catheter with multiple focuses has the beneficial effects that: compared with the prior art, the lens component arranged in the inner cavity of the catheter body comprises the coaxial component and the non-coaxial component, wherein the coaxial component can simultaneously receive and transmit the first OCT laser and the first autofluorescence laser, the non-coaxial component can separate and transmit the first OCT laser and the first autofluorescence laser and form a first focus and a second focus to act on detected tissues, and different characteristic requirements of OCT imaging and autofluorescence imaging can be simultaneously met, so that imaging quality, accuracy, image acquisition time, sensitivity and the like are relatively high.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a multi-focal multi-modality imaging catheter according to an embodiment of the present application;

FIG. 2 is a schematic diagram of the structure shown in FIG. 1B according to an embodiment of the present application;

FIG. 3 is a schematic diagram of the structure at C in FIG. 1 according to an embodiment of the present application;

FIG. 4 is a schematic structural diagram of the first embodiment E in FIG. 3 according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of a second embodiment E in fig. 3 according to an embodiment of the present application;

FIG. 6 is a schematic structural diagram of a third embodiment E in FIG. 3 according to an embodiment of the present application;

fig. 7 is a schematic structural diagram of a fourth embodiment at E in fig. 3 according to an embodiment of the present application;

FIG. 8 is a schematic diagram of a dual-clad optical fiber according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of a fifth embodiment E in fig. 3 according to an embodiment of the present application.

Reference numerals related to the above figures are as follows:

10. a catheter body;

101. a proximal tube; 1011. a proximal shaft marker; 1012. a distal shaft marker;

102. a distal tube; 1021. a distal outer tube; 1022. a spring tube; 1023. pulling back the mark; 1024. marking a lens; 1025. a guidewire lumen; 1026. a fast swap area; 1027. a reinforcing tube; 1028. a tip mark; 1029. a tip tube; 1030. a sharp port;

103. A catheter connection base; 104. a protective sleeve;

11. a first OCT laser; 111. a transmission region of the first OCT laser;

12. a first autofluorescence laser; 121. a transmission region of the first autofluorescence laser;

20. double-clad optical fibers; 201. a fiber core; 202. an inner cladding; 203. an outer cladding;

21. fusing optical fibers; 211. a single mode fiber core; 212. multimode optical fiber cladding; 213. a multimode optical fiber coating layer;

22. an optical fiber separation section;

30. a first lens unit; 301. a first lens; 302. a second lens; 303. a fifth lens;

31. a second lens unit; 311. a third lens; 312. a fourth lens;

32. a first fixing member;

33. a sixth lens; 34. a dichroic mirror;

35. a second fixing member; 36. a third fixing member;

37. a single mode optical fiber; 371. a single mode optical fiber coating layer; 38. a multimode optical fiber; 381. multimode optical fiber cladding;

40. a first hemispherical lens; 41. a second hemispherical lens;

50. a coreless optical fiber; 51. a first magnifying lens; 52. a second magnifier lens; 53. a fourth fixing member; 54. and a fifth fixing member.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application 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 for purposes of illustration only and are not intended to limit the scope of the application.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. Embodiments of the application and features of the embodiments may be combined with each other without conflict. The application will be described in detail below with reference to the drawings in connection with embodiments.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing and simplifying the description based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "plurality" is two or more unless specifically defined otherwise.

As described in the background art, the OCT system and the NIRAF system are combined, and in order to acquire the OCT signal and the NIRAF signal of the same lumen, an OCT catheter and a NIRAF catheter are fused into one catheter, that is, two beams of light with different wavelengths are transmitted by using one catheter, and then both signals are acquired simultaneously. Because of the different characteristics of OCT imaging and autofluorescence imaging, for example, OCT imaging needs to be deep, whereas the autofluorescence optical signal is weak, how to increase the signal intensity (high sensitivity), and so on. Therefore, how to make a catheter transmit two light beams simultaneously and ensure the imaging quality is a problem that needs to be solved in the art.

Referring to fig. 1 to 9, in order to solve the above problems, according to an aspect of the present application, an embodiment of the present application provides a multi-focal multi-modality imaging catheter including: the pipe body 10 and set up in the camera lens subassembly of pipe body 10 inner chamber, the camera lens subassembly includes: the coaxial component is used for receiving excitation light provided by the host system and transmitting the excitation light to the non-coaxial component, the non-coaxial component can separate the excitation light into a first OCT laser 11 and a first autofluorescence laser 12, the first OCT laser 11 forms a first focus, the first autofluorescence laser 12 forms a second focus to act on detected tissues, the detected tissues are excited to emit a second OCT laser (not shown in the figure) and a second autofluorescence laser (not shown in the figure), and the second OCT laser and the second autofluorescence laser are emitted to the host system through the lens component.

Compared with the prior art, the lens component of the inner cavity of the catheter body 10 comprises a coaxial component and a non-coaxial component, wherein the coaxial component is used for transmitting two laser beams with the same axis, and the non-coaxial component is used for transmitting two laser beams with different axes in a dispersed manner and forming different focuses. The application uses the coaxial component to transmit the first OCT laser 11 and the first autofluorescence laser 12 at the same time, then uses the non-coaxial component to transmit the two beams of light separately, and then forms the first focus and the second focus to act on the detected tissue, thus meeting the different characteristic requirements of OCT imaging and autofluorescence imaging (high sensitivity autofluorescence measurement needs a high Numerical Aperture (NA) lens to realize, and Optical Coherence Tomography (OCT) needs a low Numerical Aperture (NA) to realize deep detection distance), thereby ensuring relatively high imaging quality, precision, image acquisition time, sensitivity and the like.

The two lasers of the host system as the light source of the present application can emit light of different wavelengths, respectively OCT excitation light and autofluorescence excitation light, which are used for exciting OCT probe light and autofluorescence probe light, respectively. Preferably, the OCT excitation light may emit laser light of 1310nm and the auto-fluorescence excitation light may emit laser light of 633nm, 1310nm is used for obtaining OCT signals, 633nm is used for obtaining auto-fluorescence signals, and the auto-fluorescence detection laser wavelength, the OCT excitation light wavelength, and the auto-fluorescence excitation laser wavelength are all different. The host system is connected with the catheter body 10, and transmits two laser beams through the catheter body 10. The catheter body 10 is shown with reference to fig. 1. In addition, the detected tissue absorbs the first OCT laser light 11 and the first autofluorescence laser light 12 and is excited to emit the second OCT laser light and the second autofluorescence laser light, that is, the first OCT laser light 11 and the first autofluorescence laser light 12 are OCT excitation light and autofluorescence excitation light, respectively, and the second OCT laser light and the second autofluorescence laser light are OCT probe light and autofluorescence probe light, respectively. Wherein the wavelengths of the first OCT laser 11, the first autofluorescence laser 12, and the second autofluorescence laser are different.

Referring to fig. 2, the catheter body 10 in this embodiment includes a proximal tube 101, a distal tube 102 and a catheter connector 103 respectively connected to two ends of the proximal tube 101, wherein the catheter connector 103 is provided with a protective sleeve 104, and the catheter connector 103 is used for connecting with a host system. Specifically, the outer diameter of the proximal tube body 101 is 1000-1200 μm, and the length is 1-1.5 m; referring to fig. 2, a distal shaft marker 1012 and a proximal shaft marker 1011 are provided on the proximal tube 101 to indicate positions of 10300.9m and 1m from the tip port. Referring to FIG. 3, the distal outer tube 1021 is of a stepped structure, has an outer diameter of 800-1000 μm and a length of 20-50cm, and is coated with a lubricating coating on the outer surface, thereby improving the passage performance of the catheter; the distal tube 102 is connected to the proximal tube 101, and the fiber and spring tube 1022 enters the lumen of the distal tube 102 from the lumen of the proximal tube 101 until the fiber probe reaches a position that is between 1030 10 and 20mm from the tip end opening, facilitating scanning of the distal lesion by the fiber probe. The spring tube 1022 is provided with a lens tab 1024 and a pullback tab 1023, which are spaced 50-100cm apart for assessing lesion length and the outer diameter of the spring tube 1022 is 350-600 μm. Tip tube 1029 is a segmented polyether amide/polyethylene three-layer plastic tube with an outer diameter of 600-800 μm and a length of 3-6 mm, and distal tube 102 is provided with a tip marker 1028 near tip tube 1029. A quick exchange area 1026 is arranged between the optical fiber probe and the tip tube 1029, a guide wire cavity 1025 is arranged on the catheter body 10 in the area, a reinforced tube 1027 for the guide wire to pass through is arranged in the guide wire cavity 1025, the guide wire passes through the guide wire cavity 1025, the catheter body 10 is guided to enter the target position of the blood vessel, and a motor in the host system controls the spring tube 1022 to rotate and pull back, so that the spring tube 1022 drives the lens component to rotate and pull back.

Referring to fig. 4 to 9, the non-coaxial assembly in this embodiment includes: the coaxial assembly, the first optical transmission assembly and the second optical transmission assembly are sequentially connected; the second optical transmission component comprises a first focusing unit and a second focusing unit, the first focusing unit is arranged on the emergent path of the first OCT laser 11, so that the first OCT laser 11 forms a first focus through the first focusing unit; the second focusing unit is disposed on the outgoing path of the first autofluorescence laser 12, so that the first autofluorescence laser 12 forms a second focus through the second focusing unit. It will be appreciated that the first OCT laser 11 and the first autofluorescence laser 12 are emitted from different focusing units, which are capable of forming different focal points, so as to meet different characteristic requirements of the first OCT laser imaging and the autofluorescence imaging.

Referring to fig. 4 to 5, the first light transmission assembly in the present embodiment includes a first lens unit 30 and a second lens unit 31, the first lens unit 30 and the second lens unit 31 being disposed at a spacing; the first lens unit 30 is disposed at an output end of the coaxial assembly, and the first lens unit 30 includes: a first lens 301 and a second lens 302, the first lens 301 being disposed on a transmission path of the first OCT laser light 11 such that the first OCT laser light 11 refracted by the first lens 301 is parallel to each other; the second lens 302 is disposed on the first transmission path of the first self-fluorescent laser light 12, and the first self-fluorescent laser light 12 refracted by the second lens 302 is parallel to each other; the second lens unit 31 includes a third lens 311 and a fourth lens 312, the third lens 311 being located on a side of the first lens 301 away from the coaxial assembly, for receiving the first OCT laser light 11 refracted by the first lens 301 and transmitting to the first focusing unit; the fourth lens 312 is located at a side of the second lens 302 away from the coaxial assembly, and is configured to receive the first autofluorescence laser light 12 refracted by the second lens 302 and transmit the first autofluorescence laser light to the second focusing unit; the first lens unit 30 further includes: the fifth lens 303, the fifth lens 303 is located on the second transmission path of the first self-fluorescent laser light 12, so that the first self-fluorescent laser light 12 refracted by the fifth lens 303 is parallel to each other, and the fourth lens 312 is further located on a side of the fifth lens 303 away from the coaxial assembly, and is used for receiving the first self-fluorescent laser light 12 refracted by the fifth lens 303 and transmitting to the second focusing unit; wherein the first lens 301, the second lens 302 and the fifth lens 303 are disposed along a radial direction of the coaxial assembly, and the first lens 301 is disposed between the second lens 302 and the fifth lens 303.

In the embodiment of the present application, the parameters of the five lenses of the first lens 301, the second lens 302, the third lens 311, the fourth lens 312, and the fifth lens 303 are different, and the refractive indexes are different in order to change the transmission direction of light so that the first OCT laser 11 and the first autofluorescence laser 12 are transmitted to the first focusing unit and the second focusing unit, respectively. The first OCT laser light 11 and the first autofluorescence laser light 12 are refracted by a first lens 301, a second lens 302, and a fifth lens 303, wherein the first lens 301 is used for refracting the first OCT laser light 11, and the second lens 302 and the fifth lens 303 are used for refracting the first autofluorescence laser light 12. The above-mentioned refracted first OCT laser light 11 and first autofluorescence laser light 12 are transmitted to the third lens 311 and fourth lens 312, respectively, by refraction, and the third lens 311 and fourth lens 312 further refract the first OCT laser light and first autofluorescence laser light 12 into the first focusing unit and the second focusing unit, respectively. The third lens 311 is used for refracting the first OCT laser 11, transmitting the first OCT laser 11 to the first focusing unit, and the fourth lens 312 is used for refracting the first autofluorescence laser 12, and transmitting the first autofluorescence laser 12 to the second focusing unit. The first focusing unit and the second focusing unit are used for forming a first focus and a second focus by two laser beams respectively and acting on the tissue. The vessel segment signal is obtained by rotating the pullback, i.e. the lens assembly transmits light to the tissue in the vessel by rotating the pullback of the spring tube 1022, the tissue receives the light and reflects the corresponding light to the lens assembly, and the light is transmitted to the host system by the optical fiber.

Referring to fig. 4 to 5, the first optical transmission assembly in this embodiment further includes a first fixing member 32, two ends of the first fixing member 32 are respectively connected to the first lens unit 30 and the second lens unit 31, and the first fixing member 32 is capable of transmitting the first OCT laser 11 and the first autofluorescence laser 12 refracted by the first lens unit 30 to the second lens unit 31. It is understood that the first fixing member 32 is used to fix the first lens unit 30 and the second lens unit 31. In this embodiment, the first fixing member 32 is a crystal, which has no influence on light, and can transmit the laser light to the focusing unit on the same side.

Referring to fig. 6 to 7, the first light transmission assembly in another embodiment of the present application includes a sixth lens 33 and a dichroic mirror 34, the sixth lens 33 being connected to the output end of the coaxial assembly, so that the first OCT laser light 11 and the first autofluorescence laser light 12 refracted by the sixth lens 33 exit in parallel to the dichroic mirror 34; the dichroic mirror 34 is disposed on a side of the sixth lens 33 away from the coaxial assembly and between the first focusing unit and the second focusing unit, and is configured to transmit the first OCT laser 11 refracted by the sixth lens 33 and transmit the first OCT laser to the first focusing unit, and reflect the first autofluorescence laser 12 refracted by the sixth lens 33 and transmit the first autofluorescence laser to the second focusing unit.

In the present embodiment, the first OCT laser light 11 and the first autofluorescence laser light 12 change the divergent beam into the horizontal beam by the sixth lens 33, and the two horizontal beams are transmitted to the dichroic mirror 34, and the dichroic mirror 34 selectively transmits the first OCT laser light 11, that is, the laser light of 1310 nm. The first OCT laser 11 passes through the dichroic mirror 34 to reach the first focusing unit, and the transmitted first OCT laser 11 is reflected by the first focusing unit and focused on the detected tissue; the first autofluorescence laser light 12 is totally reflected at the dichroic mirror 34 to the second focusing unit, through which the first autofluorescence laser light 12 is focused on the tissue to be examined. The vessel segment signal is obtained by rotating the pullback, i.e. the lens assembly transmits light to the tissue in the vessel by rotating the pullback of the spring tube 1022, the tissue receives the light and reflects the corresponding light to the lens assembly, and the light is transmitted to the host system by the optical fiber.

Referring to fig. 6 to 7, the first light transmission assembly further includes a second fixing member 35 and a third fixing member 36 in the present embodiment, the second fixing member 35 is connected to the dichroic mirror 34 and the first focusing unit, the dichroic mirror 34 is further connected to the second focusing unit, and the third fixing member 36 is connected to the sixth lens 33 and the second focusing unit, respectively. In this embodiment, the second fixing member 35 and the third fixing member 36 are both crystal for transmitting laser light and fixing the first focusing unit and the second focusing unit.

Referring to fig. 4 to 8, the coaxial assembly in this embodiment includes a double-clad optical fiber 20 and a coreless optical fiber 50, the coreless optical fiber 50 is connected between the double-clad optical fiber 20 and the non-coaxial assembly, the double-clad optical fiber 20 includes a core 201, an inner cladding 202 sleeved on the core 201, and an outer cladding 203 sleeved on the inner cladding, the first OCT laser 11 is transmitted through the core 201, and the first autofluorescence laser 12 is transmitted through the inner cladding 202. Referring to fig. 8, the double-clad optical fiber 20 transmits two light beams, the double-clad optical fiber 20 is inside a spring tube 1022, and the spring tube 1022 is used to generate a rotational pullback torque force optical fiber. The first OCT laser 11 and the first autofluorescence laser 12 are transmitted by the double-clad fiber 20, and the laser is amplified by the coreless fiber 50 for facilitating subsequent imaging.

Referring to fig. 8, another embodiment of the coaxial assembly of the present application includes a fusion optical fiber 21, where the fusion optical fiber 21 has an optical fiber separation section 22, and the first optical transmission assembly includes a single-mode optical fiber 37, a multimode optical fiber 38, a first amplifying lens 51 and a second amplifying lens 52, where an input end of the single-mode optical fiber 37 and an input end of the multimode optical fiber 38 are respectively connected to the optical fiber separation section 22, and an output end of the single-mode optical fiber 37, the first amplifying lens 51 and the first focusing unit are sequentially connected, and an output end of the multimode optical fiber 38, the second amplifying lens 52 and the second focusing unit are sequentially connected; the fusion fiber 21 includes a single-mode fiber core 211, a multimode fiber cladding 212 sleeved on the single-mode fiber core 211, and a multimode fiber coating 213 sleeved on the multimode fiber cladding 212, the first OCT laser 11 is transmitted from the single-mode fiber core 211, and the first autofluorescence laser 12 is transmitted from the multimode fiber cladding 212.

In this embodiment, the single-mode fiber and the multimode fiber are fused, that is, the single-mode fiber with the coating layer removed is substituted for the core of the multimode fiber, so that a fused fiber 21 similar to the multi-clad fiber in principle is formed, the first OCT laser 11 is transmitted from the single-mode fiber core 211, and the first autofluorescence laser 12 is transmitted from the multimode fiber cladding 212. The fusion fiber 21 extends from the proximal tube 101 all the way to the distal tube 102, at the tip of the fiber probe, the fusion fiber 21 is separated into a single-mode fiber 37 and a multi-mode fiber 38 by a separation technique, the single-mode fiber 37 having a single-mode fiber coating 371, the multi-mode fiber 38 having a multi-mode fiber cladding 381, wherein the single-mode fiber 37 transmits the first OCT laser 11, the multi-mode fiber 38 transmits the first autofluorescence laser 12, and then the single-mode fiber 37 and the multi-mode fiber 38 form the laser into a first focus and a second focus by respective connected focusing units, and transmit the laser onto the tissue to be examined. Wherein the first OCT laser 11 and the first autofluorescence laser 12 are amplified by a first amplifying lens 51 and a second amplifying lens 52, respectively, which is advantageous for subsequent imaging.

Referring to fig. 8, a fourth fixing member 53 is connected between the first magnifying lens 51 and the first focusing unit in the present embodiment, and the fourth fixing member 53 is capable of transmitting the first OCT laser light 11 to the first focusing unit; a fifth fixing member 54 is connected between the second magnifying lens 52 and the second focusing unit, and the fifth fixing member 54 is capable of transmitting the first autofluorescence laser light 12 to the second focusing unit. The fourth fixing member 53 and the fifth fixing member 54 in this embodiment are both crystals, and the two crystals play a role of connecting and supporting without affecting the laser.

Referring to fig. 4 to 7, and 9, the first focusing unit in the embodiment of the present application includes a first hemispherical lens 40, and the second focusing unit includes a second hemispherical lens 41. Specific examples are as follows:

referring to fig. 4 and 5, in the first and second embodiments, the first OCT laser 11 and the first autofluorescence laser 12 are transmitted by using the double-clad optical fiber 20, the coreless optical fiber 50 amplifies the light beams, and then the light beams of the first OCT laser 11 and the first autofluorescence laser 12 are separated by using lenses with different parameters and emitted from the hemispherical lenses of the first OCT laser 11 and the first autofluorescence laser 12, respectively, and the different hemispherical lenses form different focuses, so that the imaging quality, the accuracy, the image acquisition time, the sensitivity, and the like are relatively high. Specifically, the double-clad optical fiber 20 is bonded to the coreless optical fiber 50, which amplifies the first OCT laser light 11 and the first autofluorescence laser light 12, and the amplified laser light is refracted by three lenses, namely, a first lens 301, a second lens 302, and a fifth lens 303, disposed in the transmission region 111 of the first OCT laser light and the transmission region 121 of the first autofluorescence laser light, wherein the first lens 301 is used for refracting the first OCT laser light 11, and the second lens 302 and the fifth lens 303 are used for refracting the first autofluorescence laser light 12. The two laser beams are transmitted to the third lens 311 and the fourth lens 312 through the crystal by refraction, and the third lens 311 and the fourth lens 312 further refract the two laser beams to the first hemispherical lens 40 and the second hemispherical lens 41, respectively. The third lens 311 is used for refracting the first OCT laser 11, transmitting the first OCT laser 11 to the first hemispherical lens 40, the fourth lens 312 is used for refracting the first autofluorescence laser 12, transmitting the first autofluorescence laser 12 to the second hemispherical lens 41, and forming a first focus and a second focus by two hemispherical lenses respectively to act on the detected tissue. The vessel segment signal is obtained by rotating the pullback. Wherein the first hemispherical lens 40 and the second hemispherical lens 41 each have a convex surface and a plane, and a light shielding member (not shown) is provided on the plane of the first hemispherical lens 40 and the plane of the second hemispherical lens 41 so that total reflection can be performed, and the convex surfaces of the first hemispherical lens 40 and the second hemispherical lens 41 are each disposed toward the optical fiber.

It should be noted that, in this embodiment, the above elements are bonded by glue; the outer diameter except the hemispherical lens is 250 μm-400 μm; the size of a 633nm NIRAF excitation light spot is about 35 mu m, the incident angle of the first self-fluorescence laser on the end face of the optical fiber is more than 1 degree and less than 30 degrees, the numerical aperture of a fiber core is between 0.08 and 0.12, optimally 0.08, the numerical aperture of a cladding is not less than 0.46, optimally 0.8, the loss of the fiber core is not more than 40dB/km, the loss of the cladding is not more than 15dB/km, the diameter of a core layer is between 10 and 20 mu m, and the diameter of the cladding is between 130 and 300 mu m; the length of the coreless optical fiber 50 is less than 500-800 mu m, and the laser is amplified, so that the subsequent imaging is facilitated; the length of the crystal is less than 400-500 mu m; the five lenses have different parameters and different refractive indexes, so as to change the direction of light; the NA of the first hemispherical lens 40 and the second hemispherical lens 41 is 0.8 and 0.08. The first hemispherical lens 40 and the second hemispherical lens 41 are formed by melting and grinding fused quartz, can eliminate chromatic aberration and astigmatism, have an outer diameter ranging from 120-170 μm or 300 μm to 450 μm, and have a grinding angle of 35 DEG to 60 DEG, and the grinding surface is provided with a total reflection film layer which is a metal film layer so that total reflection can be performed. The grinding length and the diameter have smaller difference so as to reduce back reflection of the inclined surface, namely the diameter is less than or equal to-50 mu m and less than or equal to the grinding length and less than or equal to the diameter; rotation pullback parameters: 500 lines a per frame; a pullback speed of 40mm/s, 200 frames per second (fps), 100 revolutions/s, a pullback distance of 60mm, and a pullback time of not more than 3 seconds.

Referring to fig. 6, in the third embodiment, the first OCT laser 11 and the first autofluorescence laser 12 are transmitted by the double-clad optical fiber 20, the coreless optical fiber 50 amplifies the light beam, the first hemispherical lens 40 is located at the front end of the optical fiber, and the second hemispherical lens 41 is located at the side of the optical fiber. A first hemispherical lens 40 at the front end of the optical fiber is used to transmit light passing through the dichroic mirror 34, and a second hemispherical lens 41 at the side of the optical fiber is used to transmit light that cannot pass through the dichroic mirror 34. Specifically, the double-clad optical fiber 20 is bonded to the coreless optical fiber 50, the coreless optical fiber 50 amplifies the first OCT laser light 11 and the first autofluorescence laser light 12, the amplified laser light changes the divergent beam into the horizontal beam by the sixth lens 33, the crystal transmits the two horizontal laser light to the dichroic mirror 34, and the dichroic mirror 34 selectively transmits the first OCT laser light 11, that is, the laser light of 1310 nm. The first autofluorescence laser light 12 is totally reflected at the dichroic mirror 34 through the crystal to the second hemispherical lens 41, and the first autofluorescence laser light 12 is focused on the detected tissue through the second hemispherical lens 41. The first OCT laser light 11 transmitted through the dichroic mirror 34 passes through the crystal to reach the first hemispherical lens 40. The two laser beams form a first focus and a second focus respectively by two hemispherical lenses to act on the detected tissue. The vessel segment signal is obtained by rotating the pullback. Wherein the first and second hemispherical lenses 40 and 41 each have a convex surface and a plane, and a light shielding member (not shown) is provided on the plane of the first hemispherical lens 40 so that total reflection can be performed, and the convex surfaces of the first and second hemispherical lenses 40 and 41 are each disposed toward the optical fiber.

It should be noted that, the above elements are bonded by glue, such as UV glue; the outer diameter of the lens except the hemispherical lens is 250-400 μm; the size of the 633nm NIRAF excitation light spot is about 35 mu m, the incident angle of the first self-fluorescence laser 12 on the end face of the optical fiber is more than 1 degree and less than 30 degrees, the numerical aperture of the fiber core is between 0.08 and 0.12, and most preferably 0.08, the numerical aperture of the cladding is not less than 0.46, and most preferably 0.8, the loss of the fiber core is not more than 40dB/km, the loss of the cladding is not more than 15dB/km, the diameter of the core is between 10 and 20 mu m, and the diameter of the cladding is between 130 and 300 mu m; the length of the coreless optical fiber 50 is less than 500-800 mu m, and the laser is amplified, so that the subsequent imaging is facilitated; the dichroic mirror 34 has a length of 350-570 μm, and the three crystals have different shapes, and the main function is to perform a connection supporting function, and under the condition of not affecting laser light, the first crystal is connected with the coreless optical fiber 50 and the dichroic mirror 34, the second crystal is connected with the dichroic mirror 34 and the first hemispherical lens 40, the third crystal is connected with the first crystal and the second hemispherical lens 41, and the 8 hemispherical second hemispherical lens 41 is fixed. Wherein the first crystal is isosceles right triangle, two sides are equal to the diameter of the optical fiber (250-400 μm), and the other side is equal to the length of the dichroic mirror (350-570 μm). The second crystal has a triangular shape on one side and a concave hemispherical shape on the other side, so that the first hemispherical lens 40 is fixed, and the diameter of the second crystal is 250 μm-400 μm. The third crystal has a rectangular shape on one side and a concave hemispherical shape on the other side, so that the second hemispherical lens 41 is fixed, and the diameter of the third crystal is 250 μm-400 μm.

The NA of the first hemispherical lens 40 and the second hemispherical lens 41 is 0.8 and 0.08. The first hemispherical lens 40 and the second hemispherical lens 41 are formed by melting and grinding fused quartz, can eliminate chromatic aberration and astigmatism, have an outer diameter ranging from 250 μm to 400 μm, and have a grinding angle ranging from 35 DEG to 60 DEG, and have a total reflection film layer, which is a metal film layer, so that total reflection can be performed. The grinding length and the diameter have smaller difference so as to reduce back reflection of the inclined surface, namely the diameter is less than or equal to-50 mu m, the grinding length is less than or equal to the diameter, and the material is quartz glass.

In this embodiment, the rotation pullback parameter: 500 lines a per frame; a pullback speed of 40mm/s, 200 frames per second (fps), 100 revolutions/s, a pullback distance of 60mm, and a pullback time of not more than 3 seconds. In the present application, the rotation-back parameter is not limited.

Referring to fig. 7, in the fourth embodiment, the double-clad fiber 20 is bonded to the coreless fiber 50, the coreless fiber 50 amplifies the first OCT laser light 11 and the first autofluorescence laser light 12, the amplified laser light changes the divergent beam into the horizontal beam by the sixth lens 33, the crystal connected between the sixth lens 33 and the second hemispherical lens 41 transmits the two horizontal laser light to the second hemispherical lens 41, the dichroic mirror 34 (the grinding surface of the hemispherical lens is transparent) is disposed on the grinding surface of the second hemispherical lens 41, the dichroic mirror 34 selectively transmits the first OCT laser light 11, that is, the laser light that is transmitted through 1310nm, the first OCT laser light 11 transmitted through the dichroic mirror 34 passes through the crystal connected between the first hemispherical lens 40 and the dichroic mirror 34, and then enters the first hemispherical lens 40 to form the first focal point to act on the tissue to be detected. The first autofluorescence laser light 12 is totally reflected at the dichroic mirror 34, and the second focal point formed by the first autofluorescence laser light 12 is focused on the detected tissue by the second hemispherical lens 41. The vessel segment signal is obtained by rotating the pullback. Wherein the first and second hemispherical lenses 40 and 41 each have a convex surface and a plane, and a light shielding member (not shown) is provided on the plane of the first hemispherical lens 40 so that total reflection can be performed, and the convex surfaces of the first and second hemispherical lenses 40 and 41 are each disposed toward the optical fiber.

The first and second hemispherical lenses 40 and 41 are disposed along the axial direction of the optical fiber, and na of the first and second hemispherical lenses 40 and 41 is 0.8 and 0.08. The hemispherical lens is formed by melting and grinding fused quartz, can eliminate chromatic aberration and astigmatism, has an outer diameter ranging from 250 mu m to 400 mu m and a grinding angle ranging from 35 DEG to 60 DEG, and is provided with a total reflection film layer which is a metal film layer, so that total reflection can be carried out. The grinding length is less different from the diameter to reduce back reflection of the inclined surface, namely the diameter is-50 μm less than the grinding length less than the diameter.

The first lens is used for connecting and supporting the coreless optical fiber 50 and the first hemispherical lens 40, and the second lens is used for connecting and supporting the first hemispherical lens 40 and the second hemispherical lens 41, and the diameters of the lenses are smaller than or equal to the diameters of the hemispherical lenses.

Referring to fig. 9, in the fourth embodiment, the fusion fiber 21 is separated to obtain a single-mode fiber 37 and a multimode fiber 38, the single-mode fiber 37 transmits the first OCT laser light 11, the multimode fiber cladding 381 transmits the first autofluorescence laser light 12, the first OCT laser light 11 and the first autofluorescence laser light 12 are amplified by a first amplifying lens 51 and a second amplifying lens 52, respectively, and then the two laser light beams are transmitted to the lens first hemispherical lens 40 and the lens second hemispherical lens 41 by a fourth fixing member 53 and a fifth fixing member 54 (both the fourth fixing member 53 and the fifth fixing member 54 are crystalline). Wherein each of the first and second hemispherical lenses 40 and 41 has a convex surface and a plane, and a light shielding member (not shown) is provided on the plane of the first hemispherical lens 40 so that total reflection can be performed, the convex surface of the first hemispherical lens 40 is connected to the first magnifier lens 51 through a lens, and the convex surface of the second hemispherical lens 41 is connected to the second magnifier lens 52 through a lens.

It should be noted that the above elements are bonded by glue, such as UV glue. The outer diameter of the lens except the hemispherical lens is 250-400 μm; the size of the 633nm NIRAF excitation light spot is about 35 mu m, the incident angle of the first self-fluorescence laser 11 on the end face of the optical fiber is more than 1 degree and less than 30 degrees, the numerical aperture of the fiber core is between 0.08 and 0.12, and most preferably 0.08, the numerical aperture of the cladding is not less than 0.46, and most preferably 0.8, the loss of the fiber core is not more than 40dB/km, the loss of the cladding is not more than 15dB/km, the diameter of the core is between 10 and 20 mu m, and the diameter of the cladding is between 130 and 300 mu m. The first and second magnifier lenses 51 and 52 magnifie the laser light for subsequent imaging.

The two crystals mainly play a role of connecting and supporting under the condition of not affecting laser.

The NA of the first hemispherical lens 40 and the second hemispherical lens 41 is 0.8 and 0.08. The hemispherical lens is formed by melting and grinding fused quartz, can eliminate chromatic aberration and astigmatism, has an outer diameter ranging from 100 mu m to 200 mu m and a grinding angle ranging from 35 DEG to 60 DEG, and is provided with a total reflection film layer which is a metal film layer, so that total reflection can be carried out. The grinding length is less different from the diameter to reduce back reflection of the inclined surface, namely the diameter is-50 μm less than the grinding length less than the diameter. The material is quartz glass.

Rotation pullback parameters: 500 lines a per frame; a pullback speed of 40mm/s, 200 frames per second (fps), 100 revolutions/s, a pullback distance of 60mm, and a pullback time of not more than 3 seconds.

In summary, implementing the diagnosis and treatment catheter provided in this embodiment has at least the following beneficial technical effects: by arranging the coaxial component and the non-coaxial component in the inner cavity of the catheter body 10, the coaxial component can simultaneously receive and transmit the first OCT laser 11 and the first autofluorescence laser 12, and the non-coaxial component can separate and transmit the first OCT laser 11 and the first autofluorescence laser 12 and form a first focus and a second focus to act on detected tissues, different characteristic requirements of OCT imaging and autofluorescence imaging can be simultaneously met, and therefore imaging quality, accuracy, image acquisition time, sensitivity and the like are relatively high.

The foregoing description of the preferred embodiments of the application is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the application.

Claims

1. A multi-modality imaging catheter for multiple focal points, comprising: catheter body (10) and set up in the camera lens subassembly of catheter body (10) inner chamber, the camera lens subassembly includes: the coaxial component is used for receiving excitation light provided by a host system and transmitting the excitation light to the non-coaxial component, the non-coaxial component can separate the excitation light into a first OCT laser (11) and a first autofluorescence laser (12), the first OCT laser (11) forms a first focus, the first autofluorescence laser (12) forms a second focus to act on detected tissues, the detected tissues are excited to emit a second OCT laser and a second autofluorescence laser, and the second OCT laser and the second autofluorescence laser are emitted to the host system through the lens component.

2. The multi-modality imaging catheter of claim 1, wherein the non-coaxial assembly comprises: the coaxial assembly, the first optical transmission assembly and the second optical transmission assembly are sequentially connected;

the second optical transmission assembly comprises a first focusing unit and a second focusing unit, the first focusing unit is arranged on an emergent path of the first OCT laser (11), and the first OCT laser (11) forms a first focus through the first focusing unit; the second focusing unit is arranged on the emergent path of the first self-fluorescence laser (12), so that the first self-fluorescence laser (12) forms a second focus through the second focusing unit.

3. The multi-modality imaging catheter of claim 2, wherein the first light transmission assembly includes a first lens unit (30) and a second lens unit (31), the first lens unit (30) and the second lens unit (31) being spaced apart;

the first lens unit (30) is disposed at an output end of the coaxial assembly, the first lens unit (30) comprising: a first lens (301) and a second lens (302), wherein the first lens (301) is disposed on a transmission path of the first OCT laser light (11) such that the first OCT laser light (11) refracted by the first lens (301) is parallel to each other; the second lens (302) is disposed on a first transmission path of the first self-fluorescence laser light (12), and the first self-fluorescence laser light (12) refracted by the second lens (302) is parallel to each other;

The second lens unit (31) comprises a third lens (311) and a fourth lens (312), wherein the third lens (311) is positioned on one side of the first lens (301) away from the coaxial assembly and is used for receiving the first OCT laser (11) refracted by the first lens (301) and transmitting the first OCT laser to the first focusing unit; the fourth lens (312) is located at one side of the second lens (302) away from the coaxial assembly, and is used for receiving the first self-fluorescence laser (12) refracted by the second lens (302) and transmitting the first self-fluorescence laser to the second focusing unit;

the first lens unit (30) further includes: a fifth lens (303), wherein the fifth lens (303) is located on a second transmission path of the first self-fluorescence laser light (12), so that the first self-fluorescence laser light (12) refracted by the fifth lens (303) is parallel to each other, and the fourth lens (312) is further located at one side of the fifth lens (303) away from the coaxial assembly, and is used for receiving the first self-fluorescence laser light (12) refracted by the fifth lens (303) and transmitting the first self-fluorescence laser light to the second focusing unit;

wherein the first lens (301), the second lens (302) and the fifth lens (303) are arranged along the radial direction of the coaxial assembly, and the first lens (301) is arranged between the second lens (302) and the fifth lens (303).

4. A multi-modality imaging catheter of claim 3, wherein the first light transmission assembly further comprises a first fixing member (32), both ends of the first fixing member (32) are respectively connected to the first lens unit (30) and the second lens unit (31), and the first fixing member (32) is capable of transmitting the first OCT laser light (11) and the first autofluorescence laser light (12) refracted by the first lens unit (30) to the second lens unit (31).

5. The multi-modality imaging catheter of claim 2, wherein the first light transmission assembly includes a sixth lens (33) and a dichroic mirror (34), the sixth lens (33) being connected to the output end of the coaxial assembly such that the first OCT laser light (11) and the first autofluorescence laser light (12) after refraction by the sixth lens (33) exit in parallel to the dichroic mirror (34); the dichroic mirror (34) is disposed on a side of the sixth lens (33) away from the coaxial assembly, and is located between the first focusing unit and the second focusing unit, and is configured to transmit the first OCT laser light (11) refracted by the sixth lens (33) and transmit the first OCT laser light to the first focusing unit, and reflect the first autofluorescence laser light (12) refracted by the sixth lens (33) and transmit the first autofluorescence laser light to the second focusing unit.

6. The multi-modality imaging catheter of claim 5, wherein the first light transmission assembly further comprises a second mount (35) and a third mount (36), the second mount (35) being connected to the dichroic mirror (34), the first focusing unit, respectively, the dichroic mirror (34) being further connected to the second focusing unit, the third mount (36) being connected to the sixth lens (33), respectively.

7. The multi-modality imaging catheter of any of claims 1 to 6, wherein the coaxial assembly includes a double-clad fiber (20) and a coreless fiber (50), the coreless fiber (50) being connected between the double-clad fiber (20) and the non-coaxial assembly, the double-clad fiber (20) including a core (201), an inner cladding (202) over the core (201), and an outer cladding (203) over the inner cladding (202), the first OCT laser (11) being transmitted through the core (201), the first autofluorescence laser (12) being transmitted through the inner cladding (202).

8. The multi-focal multi-modality imaging catheter of claim 2, wherein the coaxial assembly comprises a fusion fiber (21), the fusion fiber (21) having a fiber separation section (22), the first optical transmission assembly comprising a single-mode fiber (37), a multi-mode fiber (38), a first amplifying lens (51) and a second amplifying lens (52), the input of the single-mode fiber (37), the input of the multi-mode fiber (38) being connected to the fiber separation section (22), respectively, the output of the single-mode fiber (37), the first amplifying lens (51), the first focusing unit being connected in sequence, the output of the multi-mode fiber (38), the second amplifying lens (52), the second focusing unit being connected in sequence;

The fusion optical fiber (21) comprises a single-mode optical fiber core (211), a multimode optical fiber cladding (212) sleeved on the single-mode optical fiber core (211) and a multimode optical fiber coating layer (213) sleeved on the multimode optical fiber cladding (212), wherein the first OCT laser (11) is transmitted from the single-mode optical fiber core (211), and the first autofluorescence laser (12) is transmitted from the multimode optical fiber cladding (212).

9. The multi-modality imaging catheter of claim 8, wherein a fourth mount (53) is connected between the first magnifying lens (51) and the first focusing unit, the fourth mount (53) being capable of transmitting the first OCT laser light (11) to the first focusing unit;

a fifth fixing piece (54) is connected between the second amplifying lens (52) and the second focusing unit, and the fifth fixing piece (54) can transmit the first self-fluorescence laser (12) to the second focusing unit.

10. The multi-modality imaging catheter of claim 2, wherein the first focusing unit includes a first hemispherical lens (40) and the second focusing unit includes a second hemispherical lens (41).