Medical endoscope

Abstract

The invention provides a medical endoscope which comprises a lens module, and the lens module comprises a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from the object side to the image side. According to the technical scheme, the first lens, the second lens, the diaphragm, the third lens, the fourth lens, the fifth lens and the sixth lens are sequentially arranged from the object side to the image side, so that aberration, coma, astigmatism, field curvature and distortion are effectively inhibited; the diaphragm is arranged on the object side of the third lens, so that the aberration can be easily corrected, and the angle of the high-image-height light incident on the imaging element can be easily controlled.

Description

Background Art

[0002] Endoscopic minimally invasive technology is increasingly being used in orthopedics, and is commonly used in joint surgery, spinal surgery, and other fields. Endoscopic technology refers to a soft or hard tubular tool equipped with a light source, camera, and instrumentation that can reach the lesion through the body's natural orifices (such as the gastrointestinal tract) or a small incision made by a doctor to perform surgery. Common clinical techniques include arthroscopy, intervertebral foraminal endoscopy, and intervertebral disc endoscopy.

[0003] Patent document CN111624733A discloses an objective lens for an endoscope, which includes 6 lenses (the 5th lens and the 6th lens are combined into a cemented lens) and has a relatively small field of view, with a full field of view of about 134°. It is not only expensive and large in size, but also has a small field of view. Summary of the invention

[0004] The present application provides a medical endoscope, which is used to realize a miniaturized, large-field-of-view, high-image-quality, and low-cost endoscope.

[0005] In a first aspect, a medical endoscope is provided, comprising: a lens module, wherein:

[0006] The lens module includes a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens and a sixth lens which are arranged in sequence from the object side to the image side.

[0007] In the above technical solution, by arranging the first lens, the second lens, the aperture, the third lens, the fourth lens, the fifth lens and the sixth lens in sequence from the object side to the image side, aberrations, coma, astigmatism, field curvature and distortion are effectively suppressed; the aperture is arranged on the object side of the third lens, which is easy to correct various aberrations and easy to control the angle of high image highlight light when it is incident on the imaging element.

[0008] In a specific implementation manner, the first lens is a plano-concave lens with its concave surface facing the image side, the second lens is a meniscus lens with its convex surface facing the object side, the third lens is a bi-convex lens, the fourth lens is a bi-concave lens, the fifth lens is a meniscus lens with its convex surface facing the object side, and the sixth lens is a meniscus lens with its convex surface facing the object side.

[0009] In a specific implementation manner, the refractive indexes of the first lens and the sixth lens are both greater than 1.7;

[0010] The Abbe numbers of the first lens and the sixth lens are both greater than 49.

[0011] In a specific implementation manner, the refractive index of the third lens is less than 1.65, and the Abbe number of the third lens is greater than 60.

[0012] In a specific implementation manner, the refractive indices of the second lens, the fourth lens and the fifth lens are all greater than 1.8.

[0013] In a specific implementation scheme, the lens module satisfies the following relationship:

[0014] -2.0≤f1 / f6≤-1.5;

[0015] -2.5≤(R11+R12) / (R11-R12)≤-2.0;

[0016] 0.12≤F / TTL≤0.13;

[0017] Among them, f1 is the focal length of the first lens, f6 is the focal length of the sixth lens; R11 is the curvature radius of the object side of the sixth lens, R12 is the curvature radius of the image side of the sixth lens, TTL is the total system length of the lens module; F is the focal length of the entire medical endoscope.

[0018] In a specific implementation scheme, the lens module satisfies the following relationship:

[0019] 5.8≤f6 / F≤6.2;

[0020] Wherein, f6 is the focal length of the sixth lens; and F is the focal length of the entire medical endoscope.

[0021] In a specific implementation scheme, the lens module satisfies the following relationship:

[0022] N3<1.62, V3≧60;

[0023] N1>1.7, N6>1.7; V1≧49, V6≧49;

[0024] N2>1.8, N4>1.8, N5>1.8;

[0025] Wherein, N1-N6 are the refractive indices of the first lens to the sixth lens respectively, and V1-V6 are the Abbe numbers of the first lens to the sixth lens respectively.

[0026] In a specific implementation scheme, the lens module satisfies the following relationship:

[0027] 0.95≤f3 / F≤1.05;

[0028] Among them, f3 is the focal length of the third lens, and F is the focal length of the entire medical endoscope.

[0029] In a specific implementation scheme, the lens module satisfies the following relationship:

[0030] 2.3≤f1 / f4≤2.8;

[0031] 0.9≤f2 / f5≤1.1;

[0032] Wherein, f2 is the focal length of the third lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens;

[0033] 0.85≤D1 / F≤0.90;

[0034] Wherein, D1 is the thickness of the first lens on the optical axis, and F is the focal length of the entire medical endoscope. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of the structure of a medical endoscope provided in an embodiment of the present application;

[0036] Figure 2 A schematic diagram of the structure of the end of the endoscope head provided in an embodiment of the present application;

[0037] Figure 3 An optical structure diagram of a lens module provided in an embodiment of the present application;

[0038] Figure 4 A point diagram of a lens module provided in an embodiment of the present application;

[0039] Figure 5 Field curvature / distortion diagram of the lens module provided in the embodiment of the present application;

[0040] Figure 6 This is the MTF diagram of the lens module provided in the embodiment of the present application.

[0041] Among them, L1 is the first lens, L2 is the second lens, L3 is the third lens, L4 is the fourth lens, L5 is the fifth lens, L6 is the sixth lens, and ST is the aperture. DETAILED DESCRIPTION

[0042] The present application is further described in detail below through the accompanying drawings and embodiments. Through these descriptions, the characteristics and advantages of the present application will become clearer and more specific.

[0043] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0044] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0045] To facilitate understanding of the medical endoscope provided in the embodiment of the present application, its application scenario is first explained. The medical endoscope provided in the embodiment of the present application is used to realize a miniaturized, large field of view, high image quality, and low-cost endoscope. The application of minimally invasive endoscope technology in orthopedics is becoming more and more extensive, and is widely used in the fields of joint surgery, spinal surgery, etc. Endoscopic technology refers to a soft or hard tubular tool equipped with a light source, a camera, and an instrument. It can reach the human lesion through the natural channels of the human body (such as the gastrointestinal tract) or a small incision made by a doctor's surgery and perform surgery. Common clinical methods include arthroscopy, intervertebral foraminal endoscope, and intervertebral disc endoscope. Patent document CN111624733A discloses an objective lens for an endoscope, which includes 6 lenses (where the 5th lens and the 6th lens are combined into a cemented lens) and the field of view is relatively small, with a full field of view of about 134°. It is not only costly and bulky, but also has a small field of view. To this end, the present application provides a medical endoscope to realize a miniaturized, large field of view, high image quality, and low-cost endoscope. The following is a detailed description of the embodiment in conjunction with specific drawings.

[0046] refer to Figures 1 to 6 , Figure 1 A schematic diagram of the structure of a medical endoscope provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of the end of the endoscope head provided in an embodiment of the present application; Figure 3 An optical structure diagram of a lens module provided in an embodiment of the present application; Figure 4 A point diagram of a lens module provided in an embodiment of the present application; Figure 5 Field curvature / distortion diagram of the lens module provided in the embodiment of the present application; Figure 6 This is the MTF diagram of the lens module provided in the embodiment of the present application.

[0047] exist Figures 1 to 3 In the embodiment of the present application, a medical endoscope is provided, comprising: a lens module, wherein:

[0048] The lens module includes a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5 and a sixth lens L6 which are arranged in sequence from the object side to the image side.

[0049] In the above technical solution, by arranging the first lens, the second lens, the aperture, the third lens, the fourth lens, the fifth lens and the sixth lens in sequence from the object side to the image side, aberrations, coma, astigmatism, field curvature and distortion are effectively suppressed; the aperture is arranged on the object side of the third lens, which is easy to correct various aberrations and easy to control the angle of high image highlight light when it is incident on the imaging element.

[0050] Specifically, refer to Figures 1 to 3The medical endoscope comprises a head end, an insertion part, a liquid stop valve, an operating part and a connecting part; the head end comprises a lens module, an image sensor and a lighting module; the lens module comprises six lenses with refractive power, which include, from the object side to the image side: a first lens L1 with negative optical power; a second lens L2 with positive optical power; an aperture ST; a third lens L3 with positive optical power; a fourth lens L4 with negative optical power; a fifth lens L5 with positive optical power; and a sixth lens L6 with positive optical power.

[0051] In a specific implementation, the first lens is a plano-concave lens with a concave surface facing the image side, the second lens is a meniscus lens with a convex surface facing the object side, the third lens is a biconvex lens, the fourth lens is a biconcave lens, the fifth lens is a meniscus lens with a convex surface facing the object side, and the sixth lens is a meniscus lens with a convex surface facing the object side. Aberrations, coma, astigmatism, field curvature and distortion are effectively suppressed; the aperture is arranged on the object side of the third lens, so it is easy to correct various aberrations and easy to control the angle of high image highlight light when it is incident on the imaging element.

[0052] In a specific implementation manner, the refractive index of the first lens and the sixth lens is greater than 1.7; the Abbe number of the first lens and the sixth lens is greater than 49. The chromatic aberration and aberration of the system are effectively controlled.

[0053] In a specific implementation manner, the refractive index of the third lens is less than 1.65, and the Abbe number of the third lens is greater than 60. The chromatic aberration and the aberration of the system are effectively controlled.

[0054] In a specific embodiment, the refractive indexes of the second lens, the fourth lens and the fifth lens are all greater than 1.8. The aberration of the system is effectively controlled.

[0055] In a specific implementation scheme, the lens module satisfies the following relationship:

[0056] -2.0≤f1 / f6≤-1.5;

[0057] -2.5≤(R11+R12) / (R11-R12)≤-2.0;

[0058] 0.12≤F / TTL≤0.13;

[0059] Wherein, f1 is the focal length of the first lens, f6 is the focal length of the sixth lens, R11 is the radius of curvature of the object side of the sixth lens, R12 is the radius of curvature of the image side of the sixth lens, TTL is the total system length of the lens module, and F is the focal length of the entire medical endoscope. By satisfying the range of the above relationship, chromatic aberration, astigmatism, field curvature and distortion can be well corrected.

[0060] In a specific implementation scheme, the lens module satisfies the following relationship:

[0061] 5.8≤f6 / F≤6.2.

[0062] Wherein, f6 is the focal length of the sixth lens; F is the focal length of the entire medical endoscope. It can well correct coma, astigmatism and distortion.

[0063] In a specific implementation scheme, the lens module satisfies the following relationship:

[0064] N3<1.62, V3≧60;

[0065] N1>1.7, N6>1.7; V1≧49, V6≧49;

[0066] N2>1.8, N4>1.8, N5>1.8;

[0067] Wherein, N1 to N6 are the refractive indices of the first lens to the sixth lens, respectively, and V1 to V6 are the Abbe numbers of the first lens to the sixth lens. By satisfying the range of the above relationship, chromatic aberration can be well corrected.

[0068] In a specific implementation scheme, the lens module satisfies the following relationship:

[0069] 0.95≤f3 / F≤1.05;

[0070] Wherein, f3 is the focal length of the third lens, and F is the focal length of the entire medical endoscope. Spherical aberration, coma, astigmatism, field curvature and distortion can be well corrected.

[0071] In a specific implementation scheme, the lens module satisfies the following relationship:

[0072] 2.3≤f1 / f4≤2.8;

[0073] 0.9≤f2 / f5≤1.1;

[0074] Wherein, f2 is the focal length of the third lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens;

[0075] 0.85≤D1 / F≤0.90;

[0076] Wherein, D1 is the thickness of the first lens on the optical axis, and F is the focal length of the entire medical endoscope. By satisfying the above relationship, coma, astigmatism, field curvature and distortion can be well corrected.

[0077] Specifically, the values ​​of the relationship equations involved in the lens module are shown in the following table:

[0078] Relational value f1 / f6 -1.81 (R11+R12) / (R11-R12) -2.37 F / TTL 0.125 f6 / F 5.96 f3 / F 1.01 f1 / f4 2.57 f2 / f5 0.94 D1 / f 0.87

[0079] Table 1 Values ​​of the relational expressions involved in the lens module

[0080] The optical performance of the lens module of this embodiment is shown in Figures 4 to 6 , from the point diagram, field curvature / distortion diagram, and MTF diagram, the relevant data all meet the design requirements, and each aberration has been well corrected. Among them, the MTF at 1 / 2 maximum cutoff frequency (112lp / mm) is above 0.5, which is suitable for high-resolution image sensors and has good image quality.

[0081] The maximum field of view of this embodiment reaches 150°, which is more conducive to the detection of diseased tissues.

[0082] The basic parameters of the lens module of this embodiment are shown in the following table:

[0083]

[0084] Table 2 Basic parameters of lens module

[0085] Those skilled in the art will appreciate that the present application may be implemented as a system, method or computer program product.

[0086] Therefore, the present disclosure may be specifically implemented in the following forms, namely: it may be completely hardware, it may be completely software (including firmware, resident software, microcode, etc.), or it may be a combination of hardware and software, generally referred to herein as a "circuit", "module" or "system". In addition, in some embodiments, the present application may also be implemented in the form of a computer program product in one or more computer-readable media, and the computer-readable medium may contain computer-readable program code.

[0087] Any combination of one or more computer-readable media can be used. Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or devices, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: electrical connections with one or more wires, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In this document, computer-readable storage media can be any tangible medium containing or storing a program, which can be used by or in combination with an instruction execution system, device or device.

[0088] Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art can change, modify, replace and modify the above embodiments within the scope of the present application. On this basis, a variety of replacements and improvements can be made to the present application, all of which fall within the scope of protection of the present application.

Claims

1. A medical endoscope, characterized in that: include: Lens module, wherein: The lens module includes a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens and a sixth lens which are arranged in sequence from the object side to the image side.

2. The medical endoscope according to claim 1, characterized in that: The first lens is a plano-concave lens with a concave surface facing the image side, the second lens is a meniscus lens with a convex surface facing the object side, the third lens is a biconvex lens, the fourth lens is a biconcave lens, the fifth lens is a meniscus lens with a convex surface facing the object side, and the sixth lens is a meniscus lens with a convex surface facing the object side.

3. The medical endoscope according to claim 2, characterized in that: The refractive indexes of the first lens and the sixth lens are both greater than 1.7; The Abbe numbers of the first lens and the sixth lens are both greater than 49.

4. The medical endoscope according to claim 3, characterized in that: The refractive index of the third lens is less than 1.65, and the Abbe number of the third lens is greater than 60.

5. The medical endoscope according to claim 4, characterized in that: The refractive indexes of the second lens, the fourth lens and the fifth lens are all greater than 1.

8.

6. The medical endoscope according to claim 5, characterized in that: The lens module satisfies the following relationship: -2.0≤f1 / f6≤-1.5; -2.5≤(R11+R12) / (R11-R12)≤-2.0; 0.12≤F / TTL≤0.13; Among them, f1 is the focal length of the first lens, f6 is the focal length of the sixth lens; R11 is the curvature radius of the object side of the sixth lens, R12 is the curvature radius of the image side of the sixth lens, TTL is the total system length of the lens module; F is the focal length of the entire medical endoscope.

7. The medical endoscope according to claim 6, characterized in that: The lens module satisfies the following relationship: 5.8≤f6 / F≤6.2; Wherein, f6 is the focal length of the sixth lens; and F is the focal length of the entire medical endoscope.

8. The medical endoscope according to claim 7, characterized in that: The lens module satisfies the following relationship: N3<1.62, V3≧60; N1>1.7, N6>1.7; V1≧49, V6≧49; N2>1.8, N4>1.8, N5>1.8; Wherein, N1-N6 are the refractive indices of the first lens to the sixth lens respectively, and V1-V6 are the Abbe numbers of the first lens to the sixth lens respectively.

9. The medical endoscope according to claim 8, characterized in that: The lens module satisfies the following relationship: 0.95≤f3 / F≤1.05; Among them, f3 is the focal length of the third lens, and F is the focal length of the entire medical endoscope.

10. The medical endoscope according to claim 9, characterized in that: The lens module satisfies the following relationship: 2.3≤f1 / f4≤2.8; 0.9≤f2 / f5≤1.1; Wherein, f2 is the focal length of the third lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens; 0.85≤D1 / F≤0.90; Wherein, D1 is the thickness of the first lens on the optical axis, and F is the focal length of the entire medical endoscope.

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