Optical imaging systems and endoscopes

Abstract

The present application discloses an optical imaging system and an endoscope. The optical imaging system includes a front objective lens group, a relay rod lens mechanism, and a rear eyepiece group, which are arranged in sequence from the object side to the image side; the relay rod lens mechanism includes an odd number of rod lens groups, which are arranged in sequence from the object side to the image side along the optical axis; the rear eyepiece group includes an eighth lens, a ninth lens, and an exit pupil, which are arranged in sequence from the object side to the image side along the optical axis, the eighth lens is a double-cemented lens, and the ninth lens is a double-convex symmetrical lens; wherein the defocus of white light and fluorescence in the optical imaging system is no more than 0.02mm. The optical imaging system and endoscope of the present application can solve the problem that the endoscope optical imaging system needs to refocus when switching between white light and fluorescence modes.

Description

Technical Field

[0001] The present application relates to the field of medical device technology, and in particular to an optical imaging system and an endoscope. Background Art

[0002] Conventional white-light endoscopes are now widely used, with image resolution advancing from standard definition to high definition, facilitating the development of minimally invasive surgery. However, traditional white-light endoscopes lack disease-specific optical features, making them incapable of locating and visualizing precancerous lesions. Furthermore, the diffuse and patchy nature of certain lesions further hinders detection. With further technological advancements, fluorescence endoscopes are being used to improve the identification of diseased tissue.

[0003] In recent years, 4K laparoscopes have provided a higher-definition surgical field of view based on traditional high-definition laparoscope systems, making up for the shortcomings of conventional laparoscopes in image description, and presenting a clearer, more realistic and better surgical field of view than what can be seen with the naked eye on the big screen. The addition of fluorescence technology adds a visual mode based on conventional high-definition technology. In this mode, ICG (indocyanine green) will turn fluorescent green, clearly showing the entire lymphatic drainage path, making it easier for medical staff to find and remove sentinel lymph nodes. At the same time, in this fluorescence mode, the optical imaging system should have the ability to image with a wide spectrum, with a wavelength range covering white light (400nm-700nm) and near-infrared fluorescence (750nm-950nm). Traditional white light endoscopes can also achieve fluorescence imaging, but after switching to fluorescence mode, the object needs to be refocused, and frequent switching will affect the work efficiency of medical staff. Summary of the Invention

[0004] The main purpose of the present application is to provide an optical imaging system and an endoscope to solve the problem that the endoscope optical imaging system needs to refocus when switching between white light and fluorescence modes.

[0005] According to one aspect of the present application, an optical imaging system is provided, comprising a front objective lens group, a relay rod lens mechanism, and a rear eyepiece group, which are sequentially arranged from the object side to the image side;

[0006] The front objective lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in sequence along the optical axis from the object side to the image side, the image side surface and the object side surface of the first lens are both aspherical, the second lens is a turning prism, the object side surface of the third lens is a plane, the image side surface of the third lens is a convex surface, the fourth lens and the fifth lens are both triplet lenses, the sixth lens is a doublet lens, and the image side surface and the object side surface of the seventh lens are both aspherical;

[0007] The relay rod lens mechanism includes an odd number of rod lens groups, which are arranged in sequence along the optical axis from the object side to the image side;

[0008] The rear eyepiece assembly includes an eighth lens, a ninth lens, and an exit pupil, which are sequentially arranged along the optical axis from the object side to the image side. The eighth lens is a doublet lens, and the ninth lens is a biconvex symmetrical lens.

[0009] Wherein, the defocusing amount of the white light and the fluorescence of the optical imaging system is no more than 0.02 mm.

[0010] Furthermore, the optical imaging system satisfies the relationship: 8.2≤f / EPD≤8.7, wherein f is the effective focal length of the optical imaging system, and EPD is the entrance pupil diameter of the optical imaging system.

[0011] Furthermore, the optical imaging system satisfies the relationship: D≤6 mm, where D is the maximum diameter of the effective surface of the optical element in the optical imaging system.

[0012] Furthermore, the optical imaging system satisfies the relationship: |Dist.|≤6%, wherein |Dist.| is the absolute value of the distortion of the optical imaging system.

[0013] Furthermore, the optical imaging system satisfies the relationship: 0.9≤f9 / f 目 ≤1.1, where f9 is the effective focal length of the ninth lens, f 目 is the effective focal length of the rear eyepiece assembly.

[0014] Furthermore, the optical imaging system satisfies the relationship: 0.87≤f 物 / f≤0.92, where f 物 is the effective focal length of the optical imaging system, and f is the effective focal length of the optical imaging system.

[0015] Furthermore, the rod lens group includes a first rod lens group, a second rod lens group and a third rod lens group;

[0016] The first rod lens group, the second rod lens group and the third rod lens group are symmetrically arranged along the midpoint of the relay rod lens mechanism, and the first rod lens group, the second rod lens group and the third rod lens group each include a rod lens portion and a cemented lens portion that are separated from each other.

[0017] Furthermore, the rod lens parts of the first rod lens group and the third rod lens group each include a first rod lens and a second rod lens, and the cemented lens parts of the first rod lens group and the third rod lens group each include a first cemented lens and a second cemented lens;

[0018] The first cemented lens, the first rod lens, the second rod lens and the second cemented lens are arranged in sequence from the object side to the image side along the optical axis.

[0019] Furthermore, the rod lens portion of the second rod lens group includes a third rod lens and a fourth rod lens, and the cemented lens portion of the second rod lens group includes a third cemented lens, a fourth cemented lens, a fifth cemented lens, and a sixth cemented lens;

[0020] The third cemented lens, the third rod lens, the fourth cemented lens, the fifth cemented lens, the fourth rod lens and the sixth cemented lens are sequentially arranged along the optical axis from the object side to the image side.

[0021] On the other hand, the present application also provides an endoscope, which includes the above-mentioned optical imaging system.

[0022] In this application, the structure of the optical imaging system is improved so that the defocus between white light and fluorescence of the optical imaging system is no more than 0.02 mm, and high resolution and high definition can be maintained when the optical system switches between white light and fluorescence modes. When the optical imaging system of this application is used in an endoscope, medical staff do not need to focus the optical imaging system again when switching between white light and fluorescence modes, and can achieve confocality of white light and fluorescence modes, which can reduce the operation frequency of medical staff and facilitate rapid inspection of lesions in the lesion area. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0024] Figure 1 A schematic structural diagram of an optical imaging system disclosed in an embodiment of the present application;

[0025] Figure 2 This is a schematic structural diagram of the front-end objective lens assembly disclosed in an embodiment of the present application;

[0026] Figure 3 A schematic structural diagram of the first rod mirror group or the third rod mirror group disclosed in the embodiments of the present application;

[0027] Figure 4 This is a schematic structural diagram of the second rod mirror assembly disclosed in an embodiment of the present application;

[0028] Figure 5 This is a schematic structural diagram of the rear-end eyepiece assembly disclosed in an embodiment of the present application;

[0029] Figure 6This is a white light distortion diagram of the front-end objective lens assembly disclosed in the embodiment of this application;

[0030] Figure 7 This is a fluorescence distortion diagram of the front-end objective lens assembly disclosed in the embodiment of this application;

[0031] Figure 8 A diagram of the white light field curvature of the front-end objective lens assembly disclosed in an embodiment of the present application;

[0032] Figure 9 A fluorescence field curvature diagram of the front-end objective lens assembly disclosed in an embodiment of the present application;

[0033] Figure 10 This is a white light distortion diagram of the relay rod mirror mechanism disclosed in the embodiment of this application;

[0034] Figure 11 This is a fluorescence distortion diagram of the relay rod mirror mechanism disclosed in the embodiment of this application;

[0035] Figure 12 A diagram of the white light field curvature of the relay mirror rod mechanism disclosed in the embodiment of the present application;

[0036] Figure 13 A fluorescence field curvature diagram of the relay mirror rod mechanism disclosed in an embodiment of the present application;

[0037] Figure 14 This is a white light distortion diagram of the rear eyepiece assembly disclosed in the embodiment of this application;

[0038] Figure 15 This is a fluorescence distortion diagram of the rear eyepiece assembly disclosed in the embodiment of this application;

[0039] Figure 16 A field curvature diagram of the rear eyepiece assembly disclosed in an embodiment of the present application;

[0040] Figure 17 A field curvature diagram of the rear eyepiece assembly disclosed in an embodiment of the present application;

[0041] Figure 18 A white light distortion diagram of the optical imaging system disclosed in the embodiments of this application;

[0042] Figure 19 A fluorescence distortion diagram of the optical imaging system disclosed in an embodiment of the present application;

[0043] Figure 20 A white light field curvature diagram of the optical imaging system disclosed in an embodiment of the present application;

[0044] Figure 21 A fluorescence field curvature diagram of the optical imaging system disclosed in an embodiment of the present application;

[0045] Figure 22A diagram of the white light optical modulation function of the optical imaging system disclosed in an embodiment of the present application;

[0046] Figure 23 This is a fluorescence optical modulation function diagram of the optical imaging system disclosed in an embodiment of the present application.

[0047] The above drawings include the following reference numerals:

[0048] 10. Front objective lens group; 11. First lens; 12. Second lens; 13. Third lens; 14. Fourth lens; 15. Fifth lens; 16. Sixth lens; 17. Seventh lens; 20. Relay rod-mirror mechanism; 21. First rod-mirror group; 22. Second rod-mirror group; 23. Third rod-mirror group; 201. First rod-mirror; 202. Second rod-mirror; 203. First cemented lens; 204. Second cemented lens; 205. Third rod-mirror; 206. Fourth rod-mirror; 207. Third cemented lens; 208. Fourth cemented lens; 209. Fifth cemented lens; 210. Sixth cemented lens; 30. Rear eyepiece group; 31. Eighth lens; 32. Ninth lens; 33. Exit pupil. DETAILED DESCRIPTION

[0049] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0051] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary, not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0052] See also Figures 1 to 5 As shown, according to an embodiment of the present application, an optical imaging system is provided, which can be used for endoscopes. The optical imaging system includes a front objective lens group 10, a relay rod lens mechanism 20, and a rear eyepiece group 30 arranged in sequence from the object side to the image side.

[0053] Specifically, the front objective lens group 10 includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16 and a seventh lens 17, which are arranged in sequence along the optical axis from the object side to the image side. Among them, the image side surface and the object side surface of the first lens 11 are both aspherical surfaces, the second lens 12 is a turning prism, the object side surface of the third lens 13 is a plane, the image side surface of the third lens 13 is a convex surface, the fourth lens 14 and the fifth lens 15 are both triplet lenses, the sixth lens 16 is a doublet lens, and the image side surface and the object side surface of the seventh lens 17 are both aspherical surfaces.

[0054] In the present embodiment, the front objective lens group 10 is the core part of the optical imaging system, has positive field curvature, and has assumed the effect of improving aberration and optimizing optical performance. In the present embodiment, the object side and image side of the first lens 11 are both set to aspheric surfaces, which is not only convenient for optimizing aberration and improving the distortion of the front objective lens group 10, but also convenient for improving the optical modulation function of the marginal visual field of the optical imaging system, which is conducive to compressing the aperture of the front objective lens group 10. The second lens 12 is set to a steering prism, which can reasonably arrange the overall structure of the optical imaging system and is convenient for realizing the miniaturized design of the optical imaging system. The steering prism in the present embodiment is a 30° steering prism (i.e., a 0° viewing angle system after expansion). Of course, in other embodiments of the present application, the steering degree of the steering prism can be designed and selected according to actual use requirements, and is not specifically limited in the present application. The object side of the third lens 13 is a plane, and the image side is a convex surface, which is convenient for realizing the convergence of light and is conducive to improving the imaging resolution of the optical imaging system. The fourth lens 14 and the fifth lens 15 are both triplet lenses, which are conducive to further compressing the aperture of the front objective lens group 10 and have a good improvement effect on the field curvature of the front objective lens group 10. At the same time, setting the fourth lens 14 and the fifth lens 15 as triplet lenses is more convenient for production and measurement. The sixth lens 16 is a doublet lens, which adopts a structure of convex and concave lenses glued together. The double convex lens adopts a low refractive index (refractive index of 1.4 to 1.7) material, and the double concave lens adopts a high refractive index (refractive index of 1.7 to 2.0) material, which is conducive to optimizing the chromatic aberration of the optical imaging system. The image side surface and object side surface of the seventh lens 17 are both aspherical surfaces, and are located in front of the virtual image plane of the front objective lens group 10. It has a significant compensation effect on the field curvature and astigmatism of the optical imaging system, and can also further improve the optical performance of the edge field of the optical imaging system.

[0055] Furthermore, the relay rod lens mechanism 20 includes an odd number of rod lens groups, which are arranged sequentially along the optical axis from the object side to the image side. Specifically, the number of rod lens groups in this embodiment can be three, five, or seven. This embodiment is described using three rod lens groups, namely, a first rod lens group 21, a second rod lens group 22, and a third rod lens group 23. The first rod lens group 21, the second rod lens group 22, and the third rod lens group 23 are symmetrically arranged about the midpoint of the relay rod lens mechanism 20. During actual assembly, the relay rod lens mechanism 20 does not need to distinguish between the front and back sides, which facilitates rapid assembly of the optical imaging system and further reduces the production and processing costs of the optical imaging system in this embodiment. Furthermore, the first rod lens group 21, the second rod lens group 22, and the third rod lens group 23 all include separate rod lens portions and cemented lens portions. This arrangement facilitates the processing of the relay rod lens mechanism 20 and can, to a certain extent, reduce the accumulated errors during the processing of the relay rod lens mechanism 20. In addition, during the processing of the optical imaging system, the relay rod mirror mechanism 20 is difficult to process and difficult to center due to its relatively long length, which is not conducive to assembly. However, the present application separates the rod mirror part and the glued lens part of each group of relay rod mirror groups. During processing, the rod mirror part and the lens part can be processed separately, which can greatly reduce the processing difficulty of the relay rod mirror mechanism 20 and avoid the problem of difficulty in centering the rod mirror part. During installation, the relative positions of the separately set rod mirror part and the glued lens part can be adjusted, which is more convenient for debugging the optical imaging system.

[0056] Furthermore, the rod lens sections of the first and third rod lens groups 21 and 23 each include a first rod lens 201 and a second rod lens 202, and the cemented lens sections of the first and third rod lens groups 21 and 23 each include a first cemented lens 203 and a second cemented lens 204. The first cemented lens 203, the first rod lens 201, the second rod lens 202, and the second cemented lens 204 are arranged sequentially along the optical axis from the object side to the image side. In other words, cemented lenses are provided at both ends of the rod lens section in this embodiment. This arrangement effectively corrects the field curvature of the optical imaging system between the relay rod lens groups, improving the imaging quality of the optical imaging system. In other embodiments of the present application, the rod lens sections of the first and third rod lens groups 21 and 23 may also include three or more rod lenses. In this application, using two rod lenses not only meets the requirements of optical imaging but also reduces the production cost of the optical imaging system in this embodiment to a certain extent. Optionally, the first cemented lens 203 and the second cemented lens 204 in this embodiment are both double cemented lenses, and the first cemented lens 203 and the second cemented lens 204 are symmetrically arranged about the midpoint of the first cemented lens 203 or the second cemented lens 204, which is convenient for assembly. The double cemented lens is assembled with a combination of high (refractive index of 1.7 to 2.0) and low (refractive index of 1.4 to 1.7) refractive index materials, specifically a combination structure of convex lenses and concave lenses, which can well improve the field curvature of the optical imaging system. In addition, the double cemented lens has a simple structure and is easier to process, which can further reduce the production cost of the optical imaging system disclosed in the embodiment of the present application. Of course, in other embodiments of the present application, the number of lens blocks of the first cemented lens 203 and the second cemented lens 204 can also be designed and selected according to actual usage requirements, and is not specifically limited in this application.

[0057] The rod lens portion of the second rod lens group 22 includes a third rod lens 205 and a fourth rod lens 206, and the cemented lens portion of the second rod lens group 22 includes a third cemented lens 207, a fourth cemented lens 208, a fifth cemented lens 209 and a sixth cemented lens 210; wherein the third cemented lens 207, the third rod lens 205, the fourth cemented lens 208, the fifth cemented lens 209, the fourth rod lens 206 and the sixth cemented lens 210 are arranged in sequence along the optical axis from the object side to the image side. During actual installation, the aperture of the optical imaging system is installed between the fourth cemented lens 208 and the fifth cemented lens 209. At this time, the fourth cemented lens 208 and the fifth cemented lens 209 located on both sides of the aperture are both double cemented lenses. The double cemented lenses are assembled with a combination of high (refractive index is 1.7 to 2.0) and low (refractive index is 1.4 to 1.7) refractive index materials, specifically a combination structure of convex lens and concave lens. The fourth cemented lens 208 and the fifth cemented lens 209 can well optimize the chromatic aberration of the optical imaging system, reducing the pressure on the front-end objective lens group 10 to optimize the chromatic aberration.

[0058] Furthermore, the rear eyepiece assembly 30 in this embodiment includes an object-space telecentric structure. The aperture stop of this object-space telecentric structure is imaged at infinity by the lens in front of it, so that the principal light is parallel to the optical axis. As a result, when the object moves forward and backward, the image point on the image plane will only blur, while the position center will not change. The rear eyepiece assembly 30 in this embodiment can be used to connect with the relay rod mirror mechanism 20. The virtual image plane of the relay rod mirror mechanism 20 is used as the object plane of the rear eyepiece assembly 30. When combined with an ideal lens group, a relatively high-quality image can be obtained on the final image plane. In this application, there is a virtual image plane behind the relay rod mirror assembly. When tracing, light will converge well on this image plane. In this case, the object-space telecentric structure is used to connect well with the eyepiece assembly. In addition, the field curvature on the virtual image plane at the front end of the rear eyepiece assembly 30 is very small. The use of the object-space telecentric structure in the rear eyepiece assembly 30 can ensure good optical performance on this image plane. The rear eyepiece assembly 30 in this embodiment includes an eighth lens 31, a ninth lens 32, and an exit pupil 33, which are arranged in sequence along the optical axis from the object side to the image side. The eighth lens 31 is a doublet lens, and the ninth lens 32 is a biconvex symmetrical lens.

[0059] Furthermore, the defocus between the white light and fluorescence of the optical imaging system is no more than 0.02mm, for example, 0.02mm, 0.1mm, etc. The smaller defocus ensures that the images are clear and detailed in both white light and fluorescence imaging modes. In fluorescence imaging mode, light of a specific wavelength is usually used to excite fluorescent markers in the patient's tissue, thereby producing a contrast effect. If the defocus is properly controlled, this contrast effect can be increased, making the lesion area more obvious. In other words, by ensuring that the defocus between the white light and fluorescence of the optical imaging system is no more than 0.02mm in this embodiment, high resolution and high definition can be maintained when the optical system switches between white light and fluorescence modes. When the optical imaging system of this embodiment is used in an endoscope, medical staff do not need to refocus the optical imaging system when switching between white light and fluorescence modes, and can achieve confocality between white light and fluorescence modes, which can reduce the medical staff's operation frequency and facilitate rapid inspection of lesions in the lesion area.

[0060] Furthermore, the optical imaging system in this embodiment satisfies the relationship: 8.2 ≤ f / EPD ≤ 8.7. For example, f / EPD can be 8.2, 8.3, 8.4, 8.5, 8.6, or 8.7, where f is the effective focal length of the optical imaging system and EPD is the entrance pupil diameter of the optical imaging system. In this embodiment, by controlling the ratio of the effective focal length of the optical imaging lens to the entrance pupil diameter within a certain range, it is advantageous to control the position of the entrance pupil of the optical imaging system, improve the structural stability of the optical system, and significantly improve the diffraction limit of the optical modulation function (MTF) of the optical imaging system.

[0061] Furthermore, the optical imaging system in this embodiment satisfies the relationship: D ≤ 6 mm, where D is the maximum diameter of the effective surface of the optical elements in the optical imaging system. For example, D can be 6 mm, 5 mm, 4 mm, 3 mm, etc. By controlling the maximum diameter of the effective surface of the optical elements in the optical imaging system to be less than or equal to 6 mm, this embodiment meets the requirements for thinner and smaller optical imaging systems, making them more convenient for use in endoscopes.

[0062] Furthermore, the optical imaging system in this embodiment satisfies the relationship: |Dist.| ≤ 6%, where |Dist.| is the absolute value of the distortion of the optical imaging system. For example, |Dist.| can be 6%, 5%, 4%, 3%, 2%, and so on. By ensuring |Dist.| ≤ 6% in this embodiment, the requirement for small distortion of the optical imaging system is met, which helps reduce the aberrations of the optical imaging system and significantly improves the imaging quality of the optical imaging system. Furthermore, small optical distortion can restore the true appearance of an object to the greatest extent possible. Thus, when the optical imaging system in this embodiment is used in an endoscope, the condition of a patient's lesion can be more accurately detected.

[0063] Furthermore, the optical imaging system in this embodiment satisfies the relationship: 0.9≤f9 / f 目 ≤1.1, where f9 is the effective focal length of the ninth lens 32, f 目 is the effective focal length of the rear eyepiece group 30. For example, f9 / f 目 The examples are 0.9, 0.95, 1.0, 1.1, etc. In this embodiment, 0.9≤f9 / f 目 ≤1.1, which can effectively control the exit pupil position and size of the optical imaging system, making it easy to match a variety of bayonet lenses during use. At the same time, it can control the incident angle of the main light from the side image, improving the matching degree between the lens and the chip.

[0064] Furthermore, the optical imaging system in this embodiment satisfies the relationship: 0.87≤f 物 / f≤0.92, where f 物 is the effective focal length of the optical imaging system, and f is the effective focal length of the optical imaging system. 物 / f can be 0.87, 0.88, 0.89, 0.90, 0.91 or 0.92, etc. In this embodiment, 0.87≤f 物 / f≤0.92, which can effectively control the angle of incident light and promote the reduction of the aperture of the optical imaging system. 物 / f≤0.92, which can reasonably distribute the effective focal length of the front objective lens group 10, helps to improve the aberration of the optical imaging system, and effectively controls the field curvature and astigmatism of the optical imaging system.

[0065] The optical imaging system of the present application will be described in detail with reference to specific embodiments below.

[0066] Example 1

[0067] See Figures 1 to 23 As shown, according to the first embodiment of the present application, an optical imaging system is provided, which includes a front objective lens group 10, a relay rod lens mechanism 20 and a rear eyepiece group 30 arranged in sequence from the object side to the image side.

[0068] The front objective lens assembly 10, the intermediate rod lens mechanism 20, and the rear eyepiece assembly 30 can be made of glass, plastic, or a combination of both. This not only improves the optical performance of the optical imaging system, but also increases its strength and service life. During actual assembly, a protective glass is provided on the object side of the first lens 11 to protect the optical imaging system.

[0069] In this embodiment, the front objective lens group 10 includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16, and a seventh lens 17, which are arranged in sequence from the object side to the image side. Among them, the object side surface and the image side surface of the first lens 11 are both aspherical, and the object side surface of the first lens 11 is convex at the optical axis position, and the image side surface is concave at the optical axis position; the second lens 12 is a turning prism; the object side surface of the third lens 13 is a plane, and the image side surface is convex; the fourth lens 14 is a triplet lens, the object side surface and the image side surface of the first lens of the triplet lens are both convex, the image side surface of the second lens of the triplet lens is concave, and the image side surface of the third lens of the triplet lens is convex; the fifth lens 15 is a plurality of lenses, and the first lens of the triplet lens is a plurality of lenses. The lens 15 is also a triplet lens, the object side surface and the image side surface of the first lens of the triplet lens are both convex, the image side surface of the second lens of the triplet lens is concave, and the image side surface of the third lens of the triplet lens is convex; the sixth lens 16 is a doublet lens, the object side surface and the image side surface of the first lens of the doublet lens are both convex, and the image side surface of the second lens is concave; the object side surface and the image side surface of the seventh lens 17 are both aspherical, and the image side surface and the object side surface of the seventh lens 17 are both convex at the optical axis.

[0070] The relay rod lens mechanism 20 includes a first rod lens group 21, a second rod lens group 22, and a third rod lens group 23, which are sequentially arranged along the optical axis. The first rod lens group 21 includes a first cemented lens 203, a first rod lens 201, a second rod lens 202, and a second cemented lens 204, which are sequentially arranged from the object side to the image side. The object side and image side surfaces of the first lens of the first cemented lens 203 of the first rod lens group 21 are both convex, and the image side surface of the second lens of the first cemented lens 203 of the first rod lens group 21 is concave. The image side and object side surfaces of the first rod lens 201 of the first rod lens group 21 are both convex. The object side and image side surfaces of the second rod lens 202 of the first rod lens group 21 are both convex. The object side and image side surfaces of the first lens of the second cemented lens 204 of the first rod lens group 21 are both concave, and the image side surface of the second lens of the second cemented lens 204 of the first rod lens group 21 is convex. The second rod lens group 22 includes a third cemented lens 207, a third rod lens 205, a fourth cemented lens 208, a fifth cemented lens 209, a fourth rod lens 206, and a sixth cemented lens 210, which are arranged in order from the object side to the image side. The object side and image side of the first lens of the third cemented lens 207 of the second rod lens group 22 are both convex; the image side of the second lens of the third cemented lens 207 of the second rod lens group 22 is a concave surface; the object side and image side of the third rod lens 205 of the second rod lens group 22 are both convex; the object side and image side of the first lens of the fourth cemented lens 208 of the second rod lens group 22 are both concave; the image side of the second lens of the fourth cemented lens 208 of the second rod lens group 22 is a convex surface. The object-side and image-side surfaces of the first lens element of the fourth cemented lens 208 of the second rod-lens group 22 are both concave; the image-side surface of the second lens element of the fourth cemented lens 208 of the second rod-lens group 22 is concave; the object-side and image-side surfaces of the fourth rod-lens 206 of the second rod-lens group 22 are both convex; the object-side and image-side surfaces of the first lens element of the sixth cemented lens 210 of the second rod-lens group 22 are both concave; the image-side surface of the second lens element of the sixth cemented lens 210 of the second rod-lens group 22 is concave. The third rod-lens group 23 includes the first cemented lens 203, the first rod-lens 201, the second rod-lens 202, and the second cemented lens 204, which are arranged in order from the object side to the image side. Among them, the object side surface and the image side surface of the first lens of the first cemented lens 203 of the third rod lens group 23 are both convex surfaces; the image side surface of the second lens of the first cemented lens 203 of the third rod lens group 23 is a concave surface; the image side surface and the object side surface of the first rod lens 201 of the third rod lens group 23 are both convex surfaces; the object side surface and the image side surface of the second rod lens 202 of the third rod lens group 23 are both convex surfaces; the object side surface and the image side surface of the first lens of the second cemented lens 204 of the third rod lens group 23 are both concave surfaces; and the image side surface of the second lens of the second cemented lens 204 of the third rod lens group 23 is a convex surface.

[0071] The rear eyepiece assembly 30 includes an eighth lens 31 and a ninth lens 32, arranged sequentially from the object side to the image side. The eighth lens 31 is a doublet. The object-side and image-side surfaces of the first lens element of the eighth lens 31 are both concave, while the image-side surface of the second lens element of the eighth lens 31 is convex. Both the object-side and image-side surfaces of the ninth lens 32 are convex. The characteristics of the optical imaging system in this embodiment are shown in Table 1. Table 1 shows the characteristics of the optical imaging system in this embodiment, where the units of radius and thickness are both mm.

[0072] Table 1

[0073]

[0074]

[0075]

[0076] Figures 6 to 9 The figure shows the distortion and field curvature of the front objective lens group of the optical imaging system in this embodiment under white light and fluorescence modes. Figures 10 to 13 The figure shows the distortion and field curvature of the relay rod mirror mechanism of the optical imaging system in this embodiment in white light and fluorescence modes. Figures 14 to 17 Figure 3 shows the distortion and field curvature of the rear eyepiece group of the optical imaging system in this embodiment in white light and fluorescence modes. Figures 18 to 21 The distortion and field curvature of the overall optical imaging system in this embodiment in white light and fluorescence modes are shown, where the horizontal axis of the distortion diagram is the distortion rate (%); the horizontal axis of the field curvature diagram is the focal length, in mm, X represents the sagittal imaging surface curvature, and Y represents the meridional imaging surface curvature. Figure 22 and Figure 23 The optical modulation function diagram of the white light and fluorescence of the optical imaging system disclosed in this embodiment is shown. Figures 6 to 23 It can be seen that the optical imaging system provided in the first embodiment can achieve good imaging quality.

[0077] According to the above embodiments, it can be known that the optical imaging system of the present invention is respectively composed of a front objective lens group, a relay rod mirror mechanism, and a rear eyepiece group along the direction of light propagation. Among them, the first lens of the front objective lens group adopts an aspherical design, which can effectively improve the distortion of the optical system and plays a vital role in optimizing the field curvature at the objective lens end. The remaining lenses are all ordinary spherical lenses, which are convenient for processing and detection. The relay rod mirror mechanism includes three groups of relay rod mirror groups, and each group of relay rod mirror groups has a group of double-cemented lenses at both ends to optimize the field curvature. The structures of the first group of relay rod mirror groups and the third group of relay rod mirror groups are exactly the same. The aperture is located in the middle of the second group of relay rod mirror groups, and there is a group of double-cemented lenses on each side of the aperture to optimize chromatic aberration.

[0078] The optical imaging system provided by the present invention has an aperture of about 10 mm, an imaging system field of view of about 76°, an optical distortion of less than 6%, is compatible with an F22 (focal length f=22 mm) bayonet lens, and a rear eyepiece group field of view of 14.2°. It adopts an object-space telecentric structure, and when light is traced, it will converge well on the image plane. The object-space telecentric structure can well connect with the relay rod mirror mechanism; in addition, the field curvature on the virtual image plane at the front end of the rear eyepiece group is very small, and the rear eyepiece group uses an object-space telecentric structure, which can ensure good optical performance on the image plane. At the same time, in this application, by making the defocus between the white light and fluorescence of the optical imaging system no more than 0.02 mm, high resolution and high definition can be maintained when the optical system switches between white light and fluorescence modes. When the optical imaging system of this embodiment is used in an endoscope, medical staff do not need to focus the optical imaging system again when switching between white light and fluorescence modes. The white light and fluorescence modes can be confocal, which can reduce the operation frequency of medical staff and facilitate rapid inspection of lesions in the diseased area.

[0079] On the other hand, the embodiment of the present application further provides an endoscope, which includes the above-mentioned optical imaging system, and thus the endoscope includes all the technical effects of the above-mentioned optical imaging system. Since the technical effects of the optical imaging system have been described in detail above, they will not be repeated here.

[0080] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0081] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0082] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An optical imaging system, characterized in that: It comprises a front objective lens group (10), a relay rod lens mechanism (20) and a rear eyepiece lens group (30) which are sequentially arranged from the object side to the image side; The front objective lens group (10) comprises a first lens (11), a second lens (12), a third lens (13), a fourth lens (14), a fifth lens (15), a sixth lens (16) and a seventh lens (17) which are arranged in sequence along the optical axis from the object side to the image side, the image side surface and the object side surface of the first lens (11) are both aspheric surfaces, the second lens (12) is a turning prism, the object side surface of the third lens (13) is a plane, the image side surface of the third lens (13) is a convex surface, the fourth lens (14) and the fifth lens (15) are both triplet lenses, the sixth lens (16) is a doublet lens, and the image side surface and the object side surface of the seventh lens (17) are both aspheric surfaces; The relay rod lens mechanism (20) comprises an odd number of rod lens groups, which are arranged in sequence from the object side to the image side along the optical axis; The rear eyepiece group (30) comprises an eighth lens (31), a ninth lens (32) and an exit pupil (33) which are sequentially arranged along the optical axis from the object side to the image side, the eighth lens (31) being a doublet lens, and the ninth lens (32) being a biconvex symmetrical lens; Wherein, the defocusing amount of the white light and the fluorescence of the optical imaging system is no more than 0.02 mm.

2. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies the relationship: 8.2≤f / EPD≤8.7, where f is the effective focal length of the optical imaging system, and EPD is the entrance pupil diameter of the optical imaging system.

3. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies the relationship: D≤6 mm, where D is the maximum diameter of the effective surface of the optical element in the optical imaging system.

4. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies the relationship: |Dist.|≤6%, where |Dist.| is the absolute value of the distortion of the optical imaging system.

5. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies the relationship: 0.9≤f9 / f 目 ≤1.1, wherein f9 is the effective focal length of the ninth lens (32), f 目 is the effective focal length of the rear eyepiece assembly (30).

6. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies the relationship: 0.87≤f 物 / f≤0.92, where f 物 is the effective focal length of the optical imaging system, and f is the effective focal length of the optical imaging system.

7. The optical imaging system according to any one of claims 1 to 6, characterized in that: The rod lens group comprises a first rod lens group (21), a second rod lens group (22) and a third rod lens group (23); The first rod lens group (21), the second rod lens group (22) and the third rod lens group (23) are symmetrically arranged along the midpoint of the relay rod lens mechanism (20), and the first rod lens group (21), the second rod lens group (22) and the third rod lens group (23) all include mutually separated rod lens parts and cemented lens parts.

8. The optical imaging system according to claim 7, wherein: The rod lens parts of the first rod lens group (21) and the third rod lens group (23) both include a first rod lens (201) and a second rod lens (202); and the cemented lens parts of the first rod lens group (21) and the third rod lens group (23) both include a first cemented lens (203) and a second cemented lens (204); The first cemented lens (203), the first rod lens (201), the second rod lens (202), and the second cemented lens (204) are arranged in sequence along the optical axis from the object side to the image side.

9. The optical imaging system according to claim 7, wherein: The rod lens portion of the second rod lens group (22) includes a third rod lens (205) and a fourth rod lens (206), and the cemented lens portion of the second rod lens group (22) includes a third cemented lens (207), a fourth cemented lens (208), a fifth cemented lens (209), and a sixth cemented lens (210); The third cemented lens (207), the third rod lens (205), the fourth cemented lens (208), the fifth cemented lens (209), the fourth rod lens (206) and the sixth cemented lens (210) are arranged in sequence along the optical axis from the object side to the image side.

10. An endoscope, characterized in that: The endoscope comprises the optical imaging system according to any one of claims 1 to 9.

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