An aspherical optical system for an abdominal endoscope

Abstract

An aspherical optical system for a laparoscope, belonging to the technical field of medical devices. The aspherical optical system is composed of an objective lens system, an image relay system, and an eyepiece system. Among them, the objective lens system forms an image through 4 aspherical lenses arranged in sequence with intervals, the image relay system composed of 3 groups of doublet lenses performs image relay, and finally forms an image on the human eye or CCD through the eyepiece system composed of three lenses. The maximum distortion of the entire optical system is only -2%, ensuring that there is almost no difference between the edge imaging and the imaging at the center of the field of view. At the same time, the optical imaging quality is excellent, being close to the diffraction limit value. In the present invention, the rear of the objective lens I, the rear of the objective lens II, the front of the objective lens III, and the front of the objective lens IV are all even aspherical surfaces. Adopting a 4-surface aspherical structure can greatly display the design theoretical value, having a higher ability to clearly identify, and achieving the best match with the existing high-definition 4K imaging technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and particularly relates to an aspherical optical system for an abdominal endoscope. Background Art

[0002] With the rapid development of medical technology, the technology of using endoscopes for examinations or participating in minimally invasive surgeries has been gradually improved. An endoscope is a detection instrument integrating optics, electronics, and software. It enters through a human body orifice and reaches the lesion location to be examined, and performs real-time dynamic imaging monitoring on the lesion situation. Therefore, in order to improve the observation effect, the requirements for the high-definition performance of endoscope products are getting higher and higher, and the key technology of high-definition endoscopes is a high-definition optical system.

[0003] Most of the existing domestic endoscopes adopt spherical optical systems, which have general imaging quality and large aberrations. After the sine intensity distribution functions of various different frequencies are imaged by the optical system, the values are low, and the clarity cannot be guaranteed to the greatest extent, which will cause visual fatigue to doctors.

[0004] There are also some that adopt one or two aspherical surfaces on the market, such as an endoscope adapter optical system with internal focusing disclosed in CN112099212A, a small-size endoscope optical system disclosed in CN108873311A, and a small-aperture optical system for an endoscope disclosed in CN207473186U. Their image clarity is still not good enough, and problems such as large distortion and large aberration have not been well improved. Summary of the Invention

[0005] Aiming at the problems existing in the endoscope optical system of the prior art, such as general imaging quality, large aberrations, low values after the sine intensity distribution functions of various different frequencies are imaged by the optical system, large distortion, large aberration, inability to guarantee clarity to the greatest extent, and causing visual fatigue to doctors. The present invention provides an aspherical optical system for an abdominal endoscope, and designs that the objective lens end adopts a 4-surface aspherical optical system, which greatly reduces the distortion generated during the light transmission process. The whole system has high clarity and can obtain high-quality optical characteristics and high-definition image effects. The specific technical solution is as follows:

[0006] An aspherical optical system for an abdominal endoscope, the optical system includes an objective lens system 1, an image rotation system 2, and an eyepiece system 3. The objective lens system 1 is composed of 4 aspherical lenses, the image rotation system 2 is composed of 3 groups of doublet lenses, and the eyepiece system 3 is composed of three lenses; the total length of the optical system is 390 - 430 mm, the initial design of the field of view angle is 80 degrees, the lens diameter of the optical system is 3 - 7 mm, and there are 43 image planes in total.

[0007] In the above technical solution, the maximum distortion of the optical system is -2%.

[0008] In the above technical solution, the objective lens system 1 includes an objective lens I 1.1, an objective lens II 1.2, an objective lens III 1.3, and an objective lens IV 1.4; the objective lens I 1.1, the objective lens II 1.2, the objective lens III 1.3, and the objective lens IV 1.4 are arranged in sequence from front to back; the rear of the objective lens I 1.1, the rear of the objective lens II 1.2, the front of the objective lens III 1.3, and the front of the objective lens IV 1.4 are all even aspheres.

[0009] In the above technical solution, the center distance between the objective lens I 1.1 and the objective lens II 1.2 is 1.5 - 1.8 mm, the center distance between the objective lens II 1.2 and the objective lens III 1.3 is 0.8 - 1 mm, and the center distance between the objective lens III 1.3 and the objective lens IV 1.4 is 1 - 1.5 mm.

[0010] In the above technical solution, the front of the objective lens I 1.1 is a spherical surface with a curvature radius of -185.5 mm; the rear of the objective lens I 1.1 is an even aspherical surface with a vertex curvature radius of 3.45 mm and a k value of 1 - 3; the center thickness of the objective lens I 1.1 is 1.2 - 1.5 mm, and the refractive index is 1.8044.

[0011] In the above technical solution, the front of the objective lens II 1.2 is a spherical surface with a curvature radius of 32.285 mm; the rear of the objective lens II 1.2 is an even aspherical surface with a vertex curvature radius of -3.05 mm and a k value of -2 - 3; the center thickness of the objective lens II 1.2 is 3.8 - 4 mm, and the refractive index is 1.794.

[0012] In the above technical solution, the front of the objective lens III 1.3 is an even aspherical surface with a vertex curvature radius of -120 mm and a k value of 0 - 2; the rear of the objective lens III 1.3 is a spherical surface with a curvature radius of -12.45 mm; the center thickness of the objective lens III 1.3 is 1.4 - 2 mm, and the refractive index is 1.606.

[0013] In the above technical solution, the front of the objective lens IV 1.4 is an even aspherical surface with a vertex curvature radius of 10.36 mm and a k value of -1 - 3; the rear of the objective lens IV 1.4 is a spherical surface with a curvature radius of -6.25 mm, and the center thickness of the objective lens IV 1.4 is 2.2 - 3 mm, and the refractive index is 1.782.

[0014] In the above technical solution, the doublet lenses of the image relay system 2 are grouped by two image relay lenses. The doublet lenses are double-sided glued and bonded and edged by photosensitive glue. The spacing distance between each group of doublet lenses is 4 - 12 mm. Each group of doublet lenses includes an image relay lens I 2.1 and an image relay lens II 2.2.

[0015] In the above technical solution, the lengths of the image relay lens I 2.1 and the image relay lens II 2.2 are 35 - 40 mm, and the spacing distance between the image relay lens I 2.1 and the image relay lens II 2.2 is 3 - 8 mm.

[0016] In the above technical solution, the front curvature radius of the image relay lens I 2.1 is -18 mm, and the rear curvature radius is 18 mm.

[0017] In the above technical solution, the eyepiece system 3 includes an eyepiece lens I 3.1, an eyepiece lens II 3.2, and an eyepiece lens III 3.3. The eyepiece lens I 3.1, the eyepiece lens II 3.2, and the eyepiece lens III 3.3 are arranged in sequence front to back. The center distance between the eyepiece lens I 3.1 and the eyepiece lens II 3.2 is 6 - 8 mm, and the center distance between the eyepiece lens II 3.2 and the eyepiece lens III 3.3 is 0.5 - 4 mm.

[0018] In the above technical solution, the front of the eyepiece lens I 3.1 is a plane, the rear of the eyepiece lens I 3.1 is a spherical surface with a curvature radius of -8.56 mm, the center thickness of the eyepiece lens I 3.1 is 3.5 mm, and the refractive index is 1.814.

[0019] In the above technical solution, the front of the eyepiece lens II 3.2 is a spherical surface with a curvature radius of 16.8 mm; the rear of the eyepiece lens II 3.2 is a spherical surface with a curvature radius of -10.2 mm; the center thickness of the eyepiece lens II 3.2 is 4.5 mm, and the refractive index is 1.9013.

[0020] In the above technical solution, the front of the eyepiece lens III 3.3 is a spherical surface with a curvature radius of 16.5 mm; the rear of the eyepiece lens III 3.3 is a spherical surface with a curvature radius of -18.5 mm; the center thickness of the eyepiece lens III 3.3 is 6.5 mm, and the refractive index is 1.506.

[0021] In the above technical solution, the k value of the even aspheric surface is the conic coefficient.

[0022] A kind of aspherical optical system for abdominal endoscope of the present invention, compared with the prior art, has the beneficial effects that:

[0023] 1. The total length of the optical system designed by the present invention is 390 - 430 mm, the initial designed field angle is 80 degrees, the lens diameter of the optical system is 3 - 7 mm, and there are 43 image planes in total, having the advantages of large depth of field and large field of view.

[0024] 2. The optical system of the present invention is composed of an objective lens system, an image rotation system, and an eyepiece system. Among them, the objective lens system forms an image through 4 aspherical lenses arranged in sequence with intervals, the image rotation system composed of 3 groups (6 pieces) of doublet lenses rotates the image, and finally forms an image on the human eye or CCD through the eyepiece system composed of three lenses. The maximum distortion of the entire optical system is only -2%, ensuring that there is almost no difference between the edge imaging and the imaging at the center of the field of view, and at the same time, the optical imaging quality is excellent, being close to the diffraction limit value.

[0025] 3. The back of objective lens Ⅰ, the back of objective lens Ⅱ, the front of objective lens Ⅲ, and the front of objective lens Ⅳ in the design of the present invention are all even aspherical surfaces, a total of 4 even aspherical surfaces, adopting a 4 - surface aspherical structure. Among them, the center distances, center thicknesses, refractive indices, and the radius of curvature and k value of each even aspherical surface and each radius of curvature of the four objective lenses are designed respectively. This parameter design can show the design theoretical value to a great extent, having a higher clear recognition ability and achieving the best match with the existing high - definition 4K imaging technology; the combination of the 4 aspherical structures and spherical lenses can greatly reduce the distortion generated during the light transmission process, and the maximum distortion is only -2%.

[0026] 4. The doublet lens of the present invention is double - sided glued and ground and edged through photosensitive glue. This design can optimize the spherical aberration and chromatic aberration of the system, and at the same time, grinding and edging after gluing can effectively ensure the decentration value of the lens.

[0027] In summary, most of the existing domestic endoscopes adopt spherical optical systems, whose imaging quality is average, the aberration is large, and the numerical value is low after the sine intensity distribution functions of various different frequencies are imaged through the optical system, unable to ensure the clarity to the greatest extent, which will cause visual fatigue to doctors. While the present invention mainly designs the optical system of the abdominal cavity endoscope. The objective lens end adopts an aspherical optical system, combined with the design of parameters such as the lens spacing, radius of curvature, center thickness, and refractive index of its image rotation system and eyepiece system series, greatly reducing the distortion generated during the light transmission process. The clarity of the whole set of systems is very good, greatly obtaining high - quality optical characteristics and high - definition image effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 FIG. is a schematic structural diagram of the objective lens system of an aspherical optical system for an abdominal cavity endoscope according to an embodiment of the present invention;

[0029] Figure 2 FIG. is a schematic structural diagram of the image rotation system of an aspherical optical system for an abdominal cavity endoscope according to an embodiment of the present invention;

[0030] Figure 3 Schematic structural diagram of the eyepiece system of an aspherical optical system for an abdominal endoscope according to an embodiment of the present invention;

[0031] Figures 1-3 In the figure, 1 - objective lens system, 1.1 - objective lens Ⅰ, 1.2 - objective lens Ⅱ, 1.3 - objective lens Ⅲ, 1.4 - objective lens Ⅳ; 2 - image rotation system, 2.1 - image rotation lens Ⅰ, 2.2 - image rotation lens Ⅱ; 3 - eyepiece system, 3.1 - eyepiece lens Ⅰ, 3.2 - eyepiece lens Ⅱ, 3.3 - eyepiece lens Ⅲ.

[0032] Figure 4 Diffraction modulation transfer function diagram of all positions in the field of view of an aspherical optical system for an abdominal endoscope according to Embodiment 1 of the present invention.

[0033] Figure 5 Grid distortion diagram of an aspherical optical system for an abdominal endoscope according to Embodiment 1 of the present invention.

[0034] Figure 6 Simulated image of an aspherical optical system for an abdominal endoscope according to Embodiment 1 of the present invention. Detailed implementation manners

[0035] The following further illustrates the present invention in conjunction with specific implementation cases and attached Figures 1-6 drawings, but the present invention is not limited to these embodiments.

[0036] Embodiment 1

[0037] An aspherical optical system for an abdominal endoscope, as Figures 1-3 shown, the optical system includes an objective lens system 1, an image rotation system 2 and an eyepiece system 3. The objective lens system 1 is composed of 4 aspherical lenses, the image rotation system 2 is composed of 3 groups of doublet lenses, and the eyepiece system 3 is composed of three lenses; the total length of the optical system is 410 mm, the initial design of the field of view angle is 80 degrees, the lens diameter of the optical system is 6 mm, and there are 43 image planes in total.

[0038] The objective lens system 1 includes an objective lens Ⅰ 1.1, an objective lens Ⅱ 1.2, an objective lens Ⅲ 1.3 and an objective lens Ⅳ 1.4; the objective lens Ⅰ 1.1, the objective lens Ⅱ 1.2, the objective lens Ⅲ 1.3 and the objective lens Ⅳ 1.4 are arranged in sequence front and back; the back of the objective lens Ⅰ 1.1, the back of the objective lens Ⅱ 1.2, the front of the objective lens Ⅲ 1.3 and the front of the objective lens Ⅳ 1.4 are all even aspheres.

[0039] The center distance between the objective lens Ⅰ 1.1 and the objective lens Ⅱ 1.2 is 1.6 mm, the center distance between the objective lens Ⅱ 1.2 and the objective lens Ⅲ 1.3 is 0.9 mm, and the center distance between the objective lens Ⅲ 1.3 and the objective lens Ⅳ 1.4 is 1.2 mm.

[0040] The front of the objective lens Ⅰ 1.1 is a spherical surface with a curvature radius of -185.5 mm; the back of the objective lens Ⅰ 1.1 is an even aspherical surface with a vertex curvature radius of 3.45 mm and a k value of 2; the center thickness of the objective lens Ⅰ 1.1 is 1.3 mm and the refractive index is 1.8044.

[0041] The front of the objective lens Ⅱ 1.2 is a spherical surface with a curvature radius of 32.285 mm; the back of the objective lens Ⅱ 1.2 is an even aspherical surface with a vertex curvature radius of -3.05 mm and a k value of -1; the center thickness of the objective lens Ⅱ 1.2 is 3.9 mm and the refractive index is 1.794.

[0042] The front of the objective lens Ⅲ 1.3 is an even aspherical surface with a vertex curvature radius of -120 mm and a k value of 1; the back of the objective lens Ⅲ 1.3 is a spherical surface with a curvature radius of -12.45 mm; the center thickness of the objective lens Ⅲ 1.3 is 1.7 mm and the refractive index is 1.606.

[0043] The front of the objective lens Ⅳ 1.4 is an even aspherical surface with a vertex curvature radius of 10.36 mm and a k value of -1; the back of the objective lens Ⅳ 1.4 is a spherical surface with a curvature radius of -6.25 mm, and the center thickness of the objective lens Ⅳ 1.4 is 2.6 mm and the refractive index is 1.782.

[0044] The doublet lens of the image relay system 2 consists of 2 relay lenses in a group. The doublet lens is double-sided glued and bonded and edged by photosensitive glue; the spacing distance between each group of doublet lenses is 8 mm; each group of doublet lenses includes a relay lens Ⅰ 2.1 and a relay lens Ⅱ 2.2;

[0045] The lengths of the relay lens Ⅰ 2.1 and the relay lens Ⅱ 2.2 are 36 mm, and the spacing distance between the relay lens Ⅰ 2.1 and the relay lens Ⅱ 2.2 is 5.5 mm.

[0046] The front curvature radius of the relay lens Ⅰ 2.1 is -18 mm and the back curvature radius is 18 mm.

[0047] The eyepiece system 3 includes an eyepiece lens Ⅰ 3.1, an eyepiece lens Ⅱ 3.2 and an eyepiece lens Ⅲ 3.3; the eyepiece lens Ⅰ 3.1, the eyepiece lens Ⅱ 3.2 and the eyepiece lens Ⅲ 3.3 are arranged in sequence front and back. The center distance between the eyepiece lens Ⅰ 3.1 and the eyepiece lens Ⅱ 3.2 is 7 mm, and the center distance between the eyepiece lens Ⅱ 3.2 and the eyepiece lens Ⅲ 3.3 is 2.2 mm.

[0048] The front surface of the eyepiece lens I 3.1 is flat, and the rear surface is spherical with a curvature radius of -8.56 mm. The central thickness of the eyepiece lens I 3.1 is 3.5 mm, and the refractive index is 1.814;

[0049] The front surface of the eyepiece lens II 3.2 is spherical with a curvature radius of 16.8 mm; the rear surface of the eyepiece lens II 3.2 is spherical with a curvature radius of -10.2 mm; the central thickness of the eyepiece lens II 3.2 is 4.5 mm, and the refractive index is 1.9013;

[0050] The front surface of the eyepiece lens III 3.3 is spherical with a curvature radius of 16.5 mm; the rear surface of the eyepiece lens III 3.3 is spherical with a curvature radius of -18.5 mm; the central thickness of the eyepiece lens III 3.3 is 6.5 mm, and the refractive index is 1.506.

[0051] The aspherical optical system of this embodiment has a very good application effect. The diffraction modulation transfer function at all positions of the field of view is as Figure 4 shown, the grid distortion is as Figure 5 shown, the simulated image is as Figure 6 shown. The maximum distortion of the entire optical system is only -2%, ensuring that there is almost no difference between the edge imaging and the imaging at the center of the field of view. At the same time, the optical imaging quality is excellent and is close to the diffraction limit value. There are 43 image planes in total, greatly reducing the distortion generated during the light transmission process. The clarity of the entire system is very good, and high-quality optical characteristics and high-definition image effects are greatly obtained.

[0052] Embodiment 2

[0053] An aspherical optical system for an abdominal endoscope, as Figures 1-3 shown. The optical system includes an objective lens system 1, an image relay system 2, and an eyepiece system 3. The objective lens system 1 is composed of 4 aspherical lenses, the image relay system 2 is composed of 3 groups of doublet lenses, and the eyepiece system 3 is composed of three lenses; the total length of the optical system is 390 mm, the initial design of the field of view angle is 80 degrees, the lens diameter of the optical system is 3 mm, and there are 43 image planes in total.

[0054] The objective lens system 1 includes an objective lens I 1.1, an objective lens II 1.2, an objective lens III 1.3, and an objective lens IV 1.4; the objective lens I 1.1, the objective lens II 1.2, the objective lens III 1.3, and the objective lens IV 1.4 are arranged in sequence front and back; the rear surface of the objective lens I 1.1, the rear surface of the objective lens II 1.2, the front surface of the objective lens III 1.3, and the front surface of the objective lens IV 1.4 are all even aspheres.

[0055] The center distance between the objective lens Ⅰ 1.1 and the objective lens Ⅱ 1.2 is 1.5 mm, the center distance between the objective lens Ⅱ 1.2 and the objective lens Ⅲ 1.3 is 0.8 mm, and the center distance between the objective lens Ⅲ 1.3 and the objective lens Ⅳ 1.4 is 1 mm.

[0056] The front surface of the objective lens Ⅰ 1.1 is a spherical surface with a curvature radius of -185.5 mm; the rear surface of the objective lens Ⅰ 1.1 is an even aspherical surface with a vertex curvature radius of 3.45 mm and a k value of 1; the center thickness of the objective lens Ⅰ 1.1 is 1.2 mm and the refractive index is 1.8044.

[0057] The front surface of the objective lens Ⅱ 1.2 is a spherical surface with a curvature radius of 32.285 mm; the rear surface of the objective lens Ⅱ 1.2 is an even aspherical surface with a vertex curvature radius of -3.05 mm and a k value of -2; the center thickness of the objective lens Ⅱ 1.2 is 3.8 mm and the refractive index is 1.794.

[0058] The front surface of the objective lens Ⅲ 1.3 is an even aspherical surface with a vertex curvature radius of -120 mm and a k value of 1; the rear surface of the objective lens Ⅲ 1.3 is a spherical surface with a curvature radius of -12.45 mm; the center thickness of the objective lens Ⅲ 1.3 is 1.4 mm and the refractive index is 1.606.

[0059] The front surface of the objective lens Ⅳ 1.4 is an even aspherical surface with a vertex curvature radius of 10.36 mm and a k value of -1; the rear surface of the objective lens Ⅳ 1.4 is a spherical surface with a curvature radius of -6.25 mm, and the center thickness of the objective lens Ⅳ 1.4 is 2.2 mm and the refractive index is 1.782.

[0060] The doublet lens of the image rotation system 2 is composed of 2 image rotation lenses as a group. The doublet lens is double-sided glued and bonded and edged through photosensitive glue; the spacing distance between each group of doublet lenses is 4 mm; each group of doublet lenses includes the image rotation lens Ⅰ 2.1 and the image rotation lens Ⅱ 2.2;

[0061] The lengths of the image rotation lens Ⅰ 2.1 and the image rotation lens Ⅱ 2.2 are 35 mm, and the spacing distance between the image rotation lens Ⅰ 2.1 and the image rotation lens Ⅱ 2.2 is 3 mm.

[0062] The front-end curvature radius of the image rotation lens Ⅰ 2.1 is -18 mm, and the rear-end curvature radius is 18 mm.

[0063] The eyepiece system 3 includes the eyepiece lens Ⅰ 3.1, the eyepiece lens Ⅱ 3.2 and the eyepiece lens Ⅲ 3.3; the eyepiece lens Ⅰ 3.1, the eyepiece lens Ⅱ 3.2 and the eyepiece lens Ⅲ 3.3 are arranged in sequence front and back. The center distance between the eyepiece lens Ⅰ 3.1 and the eyepiece lens Ⅱ 3.2 is 6 mm, and the center distance between the eyepiece lens Ⅱ 3.2 and the eyepiece lens Ⅲ 3.3 is 0.5 mm.

[0064] The front surface of the eyepiece lens Ⅰ 3.1 is flat, the rear surface is spherical, with a radius of curvature of -8.56 mm, the central thickness of the eyepiece lens Ⅰ 3.1 is 3.5 mm, and the refractive index is 1.814;

[0065] The front surface of the eyepiece lens Ⅱ 3.2 is spherical, with a radius of curvature of 16.8 mm; the rear surface of the eyepiece lens Ⅱ 3.2 is spherical, with a radius of curvature of -10.2 mm; the central thickness of the eyepiece lens Ⅱ 3.2 is 4.5 mm, and the refractive index is 1.9013;

[0066] The front surface of the eyepiece lens Ⅲ 3.3 is spherical, with a radius of curvature of 16.5 mm; the rear surface of the eyepiece lens Ⅲ 3.3 is spherical, with a radius of curvature of -18.5 mm; the central thickness of the eyepiece lens Ⅲ 3.3 is 6.5 mm, and the refractive index is 1.506.

[0067] The aspherical optical system in this embodiment has a very good application effect. The maximum distortion of the entire optical system is only -2%, ensuring that there is almost no difference between the edge imaging and the imaging at the center of the field of view. At the same time, the optical imaging quality is excellent, similar to the diffraction limit value. There are 43 image planes in total, greatly reducing the distortion generated during the light transmission process. The clarity of the entire system is very good, greatly obtaining high-quality optical characteristics and high-definition image effects.

[0068] Embodiment 3

[0069] An aspherical optical system for an abdominal endoscope, as Figures 1-3 shown. The optical system includes an objective lens system 1, an image relay system 2, and an eyepiece system 3. The objective lens system 1 is composed of 4 aspherical lenses, the image relay system 2 is composed of 3 groups of doublet lenses, and the eyepiece system 3 is composed of three lenses; the total length of the optical system is 430 mm, the initial design of the field of view angle is 80 degrees, the lens diameter of the optical system is 7 mm, and there are 43 image planes in total.

[0070] The objective lens system 1 includes an objective lens Ⅰ 1.1, an objective lens Ⅱ 1.2, an objective lens Ⅲ 1.3, and an objective lens Ⅳ 1.4; the objective lens Ⅰ 1.1, the objective lens Ⅱ 1.2, the objective lens Ⅲ 1.3, and the objective lens Ⅳ 1.4 are arranged in sequence front and back; the rear surface of the objective lens Ⅰ 1.1, the rear surface of the objective lens Ⅱ 1.2, the front surface of the objective lens Ⅲ 1.3, and the front surface of the objective lens Ⅳ 1.4 are all even aspheres.

[0071] The center distance between the objective lens Ⅰ 1.1 and the objective lens Ⅱ 1.2 is 1.8 mm, the center distance between the objective lens Ⅱ 1.2 and the objective lens Ⅲ 1.3 is 1 mm, and the center distance between the objective lens Ⅲ 1.3 and the objective lens Ⅳ 1.4 is 1.5 mm.

[0072] The front surface of the objective lens I 1.1 is spherical with a radius of curvature of -185.5 mm; the rear surface of the objective lens I 1.1 is an even aspherical surface with a vertex radius of curvature of 3.45 mm and a k value of 3; the central thickness of the objective lens I 1.1 is 1.5 mm and the refractive index is 1.8044.

[0073] The front surface of the objective lens II 1.2 is spherical with a radius of curvature of 32.285 mm; the rear surface of the objective lens II 1.2 is an even aspherical surface with a vertex radius of curvature of -3.05 mm and a k value of 3; the central thickness of the objective lens II 1.2 is 4 mm and the refractive index is 1.794.

[0074] The front surface of the objective lens III 1.3 is an even aspherical surface with a vertex radius of curvature of -120 mm and a k value of 2; the rear surface of the objective lens III 1.3 is spherical with a radius of curvature of -12.45 mm; the central thickness of the objective lens III 1.3 is 2 mm and the refractive index is 1.606.

[0075] The front surface of the objective lens IV 1.4 is an even aspherical surface with a vertex radius of curvature of 10.36 mm and a k value of 3; the rear surface of the objective lens IV 1.4 is spherical with a radius of curvature of -6.25 mm, the central thickness of the objective lens IV 1.4 is 3 mm and the refractive index is 1.782.

[0076] The doublet lens of the image relay system 2 consists of 2 relay lenses as a group. The doublet lens is double-sided glued and bonded and edged by photosensitive glue; the spacing distance between each group of doublet lenses is 12 mm; each group of doublet lenses includes relay lens I 2.1 and relay lens II 2.2;

[0077] The lengths of relay lens I 2.1 and relay lens II 2.2 are 40 mm, and the spacing distance between relay lens I 2.1 and relay lens II 2.2 is 8 mm.

[0078] The front end radius of curvature of relay lens I 2.1 is -18 mm, and the rear end radius of curvature is 18 mm.

[0079] The eyepiece system 3 includes eyepiece lens I 3.1, eyepiece lens II 3.2 and eyepiece lens III 3.3; eyepiece lens I 3.1, eyepiece lens II 3.2 and eyepiece lens III 3.3 are arranged in sequence front and back. The center distance between eyepiece lens I 3.1 and eyepiece lens II 3.2 is 8 mm, and the center distance between eyepiece lens II 3.2 and eyepiece lens III 3.3 is 4 mm.

[0080] The front surface of eyepiece lens I 3.1 is flat, the rear surface of eyepiece lens I 3.1 is spherical with a radius of curvature of -8.56 mm, the central thickness of eyepiece lens I 3.1 is 3.5 mm and the refractive index is 1.814;

[0081] The front surface of the eyepiece lens II 3.2 is spherical with a radius of curvature of 16.8 mm; the rear surface of the eyepiece lens II 3.2 is spherical with a radius of curvature of -10.2 mm; the central thickness of the eyepiece lens II 3.2 is 4.5 mm and the refractive index is 1.9013;

[0082] The front surface of the eyepiece lens III 3.3 is spherical with a radius of curvature of 16.5 mm; the rear surface of the eyepiece lens III 3.3 is spherical with a radius of curvature of -18.5 mm; the central thickness of the eyepiece lens III 3.3 is 6.5 mm and the refractive index is 1.506.

[0083] The aspherical optical system of this embodiment has a very good applicable effect. The maximum distortion of the entire optical system is only -2%, ensuring that there is almost no difference between the edge imaging and the imaging at the center of the field of view. At the same time, the optical imaging quality is excellent and is close to the diffraction limit value. There are a total of 43 image planes, greatly reducing the distortion generated during the light transmission process. The clarity of the entire system is very good, greatly obtaining high-quality optical characteristics and high-definition image effects.

[0084] Embodiment 4

[0085] An aspherical optical system for an abdominal endoscope, as Figures 1-3 shown. The optical system includes an objective lens system 1, an image relay system 2, and an eyepiece system 3. The objective lens system 1 is composed of 4 aspherical lenses, the image relay system 2 is composed of 3 groups of doublet lenses, and the eyepiece system 3 is composed of three lenses; the total length of the optical system is 400 mm, the initial designed field of view angle is 80 degrees, the lens diameter of the optical system is 4 mm, and there are a total of 43 image planes.

[0086] The objective lens system 1 includes an objective lens I 1.1, an objective lens II 1.2, an objective lens III 1.3, and an objective lens IV 1.4; the objective lens I 1.1, the objective lens II 1.2, the objective lens III 1.3, and the objective lens IV 1.4 are arranged in sequence from front to back; the rear surface of the objective lens I 1.1, the rear surface of the objective lens II 1.2, the front surface of the objective lens III 1.3, and the front surface of the objective lens IV 1.4 are all even aspheres.

[0087] The center distance between the objective lens I 1.1 and the objective lens II 1.2 is 1.6 mm, the center distance between the objective lens II 1.2 and the objective lens III 1.3 is 0.9 mm, and the center distance between the objective lens III 1.3 and the objective lens IV 1.4 is 1.1 mm.

[0088] The front surface of the objective lens I 1.1 is spherical with a radius of curvature of -185.5 mm; the rear surface of the objective lens I 1.1 is an even asphere with a vertex radius of curvature of 3.45 mm and a k value of 1.5; the central thickness of the objective lens I 1.1 is 1.3 mm and the refractive index is 1.8044.

[0089] The front surface of the objective lens II 1.2 is spherical with a radius of curvature of 32.285 mm; the rear surface of the objective lens II 1.2 is an even aspherical surface with a vertex radius of curvature of -3.05 mm and a k value of -1; the central thickness of the objective lens II 1.2 is 3.8 mm and the refractive index is 1.794.

[0090] The front surface of the objective lens III 1.3 is an even aspherical surface with a vertex radius of curvature of -120 mm and a k value of 1; the rear surface of the objective lens III 1.3 is spherical with a radius of curvature of -12.45 mm; the central thickness of the objective lens III 1.3 is 1.5 mm and the refractive index is 1.606.

[0091] The front surface of the objective lens IV 1.4 is an even aspherical surface with a vertex radius of curvature of 10.36 mm and a k value of -1; the rear surface of the objective lens IV 1.4 is spherical with a radius of curvature of -6.25 mm, the central thickness of the objective lens IV 1.4 is 2.3 mm and the refractive index is 1.782.

[0092] The doublet lenses of the image relay system 2 are grouped in sets of 2 relay lenses. The doublet lenses are double-sided glued and bonded and edged by photosensitive glue; the spacing between each set of doublet lenses is 5 mm; each set of doublet lenses includes relay lens I 2.1 and relay lens II 2.2;

[0093] The lengths of relay lens I 2.1 and relay lens II 2.2 are 36 mm, and the spacing between relay lens I 2.1 and relay lens II 2.2 is 4 mm.

[0094] The front end radius of curvature of relay lens I 2.1 is -18 mm, and the rear end radius of curvature is 18 mm.

[0095] The eyepiece system 3 includes eyepiece lens I 3.1, eyepiece lens II 3.2 and eyepiece lens III 3.3; the eyepiece lens I 3.1, eyepiece lens II 3.2 and eyepiece lens III 3.3 are arranged in sequence front to back, the center distance between the eyepiece lens I 3.1 and the eyepiece lens II 3.2 is 6.5 mm, and the center distance between the eyepiece lens II 3.2 and the eyepiece lens III 3.3 is 1 mm.

[0096] The front surface of the eyepiece lens I 3.1 is flat, the rear surface of the eyepiece lens I 3.1 is spherical with a radius of curvature of -8.56 mm, the central thickness of the eyepiece lens I 3.1 is 3.5 mm and the refractive index is 1.814;

[0097] The front surface of the eyepiece lens II 3.2 is spherical with a radius of curvature of 16.8 mm; the rear surface of the eyepiece lens II 3.2 is spherical with a radius of curvature of -10.2 mm; the central thickness of the eyepiece lens II 3.2 is 4.5 mm and the refractive index is 1.9013;

[0098] The front surface of the eyepiece lens Ⅲ 3.3 is a spherical surface with a radius of curvature of 16.5 mm; the rear surface of the eyepiece lens Ⅲ 3.3 is a spherical surface with a radius of curvature of -18.5 mm; the central thickness of the eyepiece lens Ⅲ 3.3 is 6.5 mm, and the refractive index is 1.506.

[0099] The aspherical optical system of this embodiment has a very good application effect. The maximum distortion of the entire optical system is only -2%, ensuring that there is almost no difference between the imaging at the edge and the imaging at the center of the field of view. At the same time, the optical imaging quality is excellent, being close to the diffraction limit value. There are a total of 43 image planes, greatly reducing the distortion generated during the light transmission process. The clarity of the entire system is very good, greatly obtaining high-quality optical characteristics and high-definition image effects.

[0100] Embodiment 5

[0101] An aspherical optical system for an abdominal endoscope, as Figures 1-3 shown, the optical system includes an objective lens system 1, an image relay system 2, and an eyepiece lens system 3. The objective lens system 1 is composed of 4 aspherical lenses, the image relay system 2 is composed of 3 groups of doublet lenses, and the eyepiece lens system 3 is composed of three lenses; the total length of the optical system is 420 mm, the initial design of the field of view angle is 80 degrees, the lens diameter of the optical system is 5 mm, and there are a total of 43 image planes.

[0102] The objective lens system 1 includes an objective lens Ⅰ 1.1, an objective lens Ⅱ 1.2, an objective lens Ⅲ 1.3, and an objective lens Ⅳ 1.4; the objective lens Ⅰ 1.1, the objective lens Ⅱ 1.2, the objective lens Ⅲ 1.3, and the objective lens Ⅳ 1.4 are arranged in sequence front and back; the rear surface of the objective lens Ⅰ 1.1, the rear surface of the objective lens Ⅱ 1.2, the front surface of the objective lens Ⅲ 1.3, and the front surface of the objective lens Ⅳ 1.4 are all even aspherical surfaces.

[0103] The center distance between the objective lens Ⅰ 1.1 and the objective lens Ⅱ 1.2 is 1.7 mm, the center distance between the objective lens Ⅱ 1.2 and the objective lens Ⅲ 1.3 is 0.95 mm, and the center distance between the objective lens Ⅲ 1.3 and the objective lens Ⅳ 1.4 is 1.4 mm.

[0104] The front surface of the objective lens Ⅰ 1.1 is a spherical surface with a radius of curvature of -185.5 mm; the rear surface of the objective lens Ⅰ 1.1 is an even aspherical surface with a vertex radius of curvature of 3.45 mm and a k value of 2.5; the central thickness of the objective lens Ⅰ 1.1 is 1.4 mm, and the refractive index is 1.8044.

[0105] The front surface of the objective lens Ⅱ 1.2 is a spherical surface with a radius of curvature of 32.285 mm; the rear surface of the objective lens Ⅱ 1.2 is an even aspherical surface with a vertex radius of curvature of -3.05 mm and a k value of 2.5; the central thickness of the objective lens Ⅱ 1.2 is 4 mm, and the refractive index is 1.794.

[0106] The front surface of the objective lens III 1.3 is an even aspherical surface with a vertex curvature radius of -120 mm and a k value of 1.8; the rear surface of the objective lens III 1.3 is a spherical surface with a curvature radius of -12.45 mm; the central thickness of the objective lens III 1.3 is 1.9 mm and the refractive index is 1.606.

[0107] The front surface of the objective lens IV 1.4 is an even aspherical surface with a vertex curvature radius of 10.36 mm and a k value of 2.5; the rear surface of the objective lens IV 1.4 is a spherical surface with a curvature radius of -6.25 mm, the central thickness of the objective lens IV 1.4 is 2.8 mm and the refractive index is 1.782.

[0108] The doublet lens of the image conversion system 2 is grouped by 2 image conversion lenses. The doublet lens is double-sided glued and bonded and edged by photosensitive glue; the spacing distance between each group of doublet lenses is 10 mm; each group of doublet lenses includes the image conversion lens I 2.1 and the image conversion lens II 2.2;

[0109] The lengths of the image conversion lens I 2.1 and the image conversion lens II 2.2 are 39 mm, and the spacing distance between the image conversion lens I 2.1 and the image conversion lens II 2.2 is 7 mm.

[0110] The front-end curvature radius of the image conversion lens I 2.1 is -18 mm and the rear-end curvature radius is 18 mm.

[0111] The eyepiece system 3 includes an eyepiece lens I 3.1, an eyepiece lens II 3.2 and an eyepiece lens III 3.3; the eyepiece lens I 3.1, the eyepiece lens II 3.2 and the eyepiece lens III 3.3 are arranged in sequence front and back, the central distance between the eyepiece lens I 3.1 and the eyepiece lens II 3.2 is 7.5 mm, and the central distance between the eyepiece lens II 3.2 and the eyepiece lens III 3.3 is 3 mm.

[0112] The front surface of the eyepiece lens I 3.1 is a plane, the rear surface of the eyepiece lens I 3.1 is a spherical surface with a curvature radius of -8.56 mm, the central thickness of the eyepiece lens I 3.1 is 3.5 mm and the refractive index is 1.814;

[0113] The front surface of the eyepiece lens II 3.2 is a spherical surface with a curvature radius of 16.8 mm; the rear surface of the eyepiece lens II 3.2 is a spherical surface with a curvature radius of -10.2 mm; the central thickness of the eyepiece lens II 3.2 is 4.5 mm and the refractive index is 1.9013;

[0114] The front surface of the eyepiece lens III 3.3 is a spherical surface with a curvature radius of 16.5 mm; the rear surface of the eyepiece lens III 3.3 is a spherical surface with a curvature radius of -18.5 mm; the central thickness of the eyepiece lens III 3.3 is 6.5 mm and the refractive index is 1.506.

[0115] The aspherical optical system in this embodiment has a very good applicable effect. The maximum distortion of the entire optical system is only -2%, ensuring that there is almost no difference between the imaging at the edge and the imaging at the center of the field of view. At the same time, the optical imaging quality is excellent and is close to the diffraction limit value. There are a total of 43 image planes, greatly reducing the distortion generated during the light transmission process. The clarity of the entire system is very good, greatly obtaining high-quality optical characteristics and high-definition image effects.

Claims

1. An aspherical optical system for an abdominal endoscope, characterized in that The optical system includes an objective lens system (1), an image relay system (2), and an eyepiece system (3). The objective lens system (1) consists of 4 aspherical lenses, the image relay system (2) consists of 3 groups of doublet lenses, and the eyepiece system (3) consists of three lenses. The total length of the optical system is 390 - 430 mm, the initial designed field of view angle is 80 degrees, the lens diameter of the optical system is 3 - 7 mm, and there are 43 image planes in total. The objective lens system (1) includes an objective lens I (1.1), an objective lens II (1.2), an objective lens III (1.3), and an objective lens IV (1.4). The objective lens I (1.1), the objective lens II (1.2), the objective lens III (1.3), and the objective lens IV (1.4) are arranged in sequence front to back. The rear of the objective lens I (1.1), the rear of the objective lens II (1.2), the front of the objective lens III (1.3), and the front of the objective lens IV (1.4) are all even aspheres. The center distance between the objective lens I (1.1) and the objective lens II (1.2) is 1.5 - 1.8 mm, the center distance between the objective lens II (1.2) and the objective lens III (1.3) is 0.8 - 1 mm, and the center distance between the objective lens III (1.3) and the objective lens IV (1.4) is 1 - 1.5 mm. The front of the objective lens I (1.1) is a spherical surface with a curvature radius of -185.5 mm. The rear of the objective lens I (1.1) is an even aspherical surface with a vertex curvature radius of 3.45 mm and a k value of 1 - 3. The center thickness of the objective lens I (1.1) is 1.2 - 1.5 mm, and the refractive index is 1.8044. The front of the objective lens II (1.2) is a spherical surface with a curvature radius of 32.285 mm. The rear of the objective lens II (1.2) is an even aspherical surface with a vertex curvature radius of -3.05 mm and a k value of -2 - 3. The center thickness of the objective lens II (1.2) is 3.8 - 4 mm, and the refractive index is 1.

794. The front of the objective lens III (1.3) is an even aspherical surface with a vertex curvature radius of -120 mm and a k value of 0 - 2. The rear of the objective lens III (1.3) is a spherical surface with a curvature radius of -12.45 mm. The center thickness of the objective lens III (1.3) is 1.4 - 2 mm, and the refractive index is 1.

606. The front of the objective lens IV (1.4) is an even aspherical surface with a vertex curvature radius of 10.36 mm and a k value of -1 - 3. The rear of the objective lens IV (1.4) is a spherical surface with a curvature radius of -6.25 mm. The center thickness of the objective lens IV (1.4) is 2.2 - 3 mm, and the refractive index is 1.

782.

2. The aspherical optical system for an abdominal endoscope according to claim 1, characterized in that, The doublet lens of the image relay system (2) is grouped by two image relay lenses. The doublet lens is glued on both sides and bonded and edged by photosensitive glue. The spacing distance between each group of doublet lenses is 4 - 12 mm. Each group of doublet lenses includes an image relay lens I (2.1) and an image relay lens II (2.2). The lengths of the image relay lens I (2.1) and the image relay lens II (2.2) are 35 - 40 mm, and the spacing distance between the image relay lens I (2.1) and the image relay lens II (2.2) is 3 - 8 mm. The front curvature radius of the image relay lens I (2.1) is -18 mm, and the rear curvature radius is 18 mm.

3. The aspherical optical system for an abdominal endoscope according to claim 1, wherein The eyepiece system (3) includes an eyepiece lens I (3.1), an eyepiece lens II (3.2), and an eyepiece lens III (3.3). The eyepiece lens I (3.1), the eyepiece lens II (3.2), and the eyepiece lens III (3.3) are arranged in sequence front to back. The center distance between the eyepiece lens I (3.1) and the eyepiece lens II (3.2) is 6 - 8 mm, and the center distance between the eyepiece lens II (3.2) and the eyepiece lens III (3.3) is 0.5 - 4 mm.

4. The aspherical optical system for an abdominal endoscope according to claim 3, wherein The front surface of the eyepiece lens I (3.1) is a plane, the rear surface is a spherical surface with a curvature radius of -8.56 mm, the center thickness of the eyepiece lens I (3.1) is 3.5 mm, and the refractive index is 1.

814. The front surface of the eyepiece lens II (3.2) is a spherical surface with a curvature radius of 16.8 mm; the rear surface is a spherical surface with a curvature radius of -10.2 mm; the center thickness of the eyepiece lens II (3.2) is 4.5 mm, and the refractive index is 1.9013. The front surface of the eyepiece lens III (3.3) is a spherical surface with a curvature radius of 16.5 mm; the rear surface is a spherical surface with a curvature radius of -18.5 mm; the center thickness of the eyepiece lens III (3.3) is 6.5 mm, and the refractive index is 1.506.

Images