A rigid tube optical microscope endoscope and its objective lens

Abstract

The present invention belongs to the field of endoscopes, and particularly relates to a rigid tube optical microscope endoscope and its objective lens, wherein the objective lens is provided with a first negative power lens, a first positive power triplet lens group, a second positive power triplet lens group, and a fifth positive power lens in sequence from the object side to the image side; wherein: the first positive power triplet lens group is composed of a second negative power lens, a first positive power lens, and a second positive power lens; the second positive power triplet lens group is composed of a third positive power lens, a third negative power lens, and a fourth positive power lens. The endoscope objective lens of the present invention is composed of a first negative power lens, a first positive power triplet lens group, a second positive power triplet lens group, and a fifth positive power lens, which solves the problem of lens miniaturization while improving imaging quality to 8K.

Description

Technical Field

[0001] The invention belongs to the field of endoscopes, and in particular relates to a hard-tube optical microendoscope and an objective lens thereof. Background Art

[0002] A medical endoscope is a minimally invasive medical device that typically enters the body through natural channels or small incisions. Doctors use the endoscope to observe internal tissues and organs and, in conjunction with other minimally invasive surgical instruments, perform procedures. Endoscopes can reveal lesions that X-rays cannot, making them extremely valuable to doctors. With technological advancements and breakthroughs in CMOS imaging technology, 4K-quality images have become commonplace, and in some high-end applications, 8K is already being adopted. However, current endoscopic camera systems are limited by the optical system's image quality and cannot meet the detailed, detailed observation requirements of doctors. Currently, there is no effective solution to the challenge of increasing image quality from 4K to 8K while miniaturizing the endoscope.

[0003] Based on the above content, a rigid tube optical microendoscope and its objective lens are proposed. Summary of the Invention

[0004] The present invention aims to solve the technical problems existing in the prior art and proposes an endoscope objective lens design that improves the imaging quality to 8K while solving the problem of lens miniaturization.

[0005] The above purpose is achieved by the following preparation process:

[0006] The present invention provides a rigid tube optical microscope endoscope objective lens, wherein the objective lens is provided with a first negative power lens, a first positive power triplet lens group, a second positive power triplet lens group, and a fifth positive power lens in sequence from the object side to the image side; wherein:

[0007] The first positive power triplet lens group consists of a second negative power lens, a first positive power lens, and a second positive power lens;

[0008] The second positive power triplet lens group consists of a third positive power lens, a third negative power lens and a fourth positive power lens.

[0009] As a further improvement of the above technical solution, the first negative power lens is a single-group planar meniscus concave lens;

[0010] The second negative power lens is a plano-concave lens, the first positive power lens is a biconvex lens, and the second positive power lens is a meniscus convex lens;

[0011] The third positive power lens is a biconvex lens, the third negative power lens is a biconcave lens, and the fourth positive power lens is a biconvex lens;

[0012] The fifth positive power single lens is a single-group biconvex lens.

[0013] As a further improvement of the above technical solution, the F number of the objective lens is 2.4.

[0014] The first negative power lens has a convex surface on the side close to the object plane and a concave surface on the side close to the image plane;

[0015] The second negative power lens has a flat surface on the side close to the object plane and a concave surface on the side close to the image plane;

[0016] The first positive power lens has a convex surface on the side close to the object plane and a convex surface on the side close to the image plane;

[0017] The second positive power lens has a concave surface on the side close to the object plane and a convex surface on the side close to the image plane;

[0018] The third positive power lens has a convex surface on the side close to the object plane and a convex surface on the side close to the image plane;

[0019] The third negative power lens has a concave surface on the side close to the object plane and a concave surface on the side close to the image plane;

[0020] The fourth positive power lens has a convex surface on the side close to the object plane and a convex surface on the side close to the image plane;

[0021] The fifth positive power lens has a convex surface on the side close to the object plane and a convex surface on the side close to the image plane.

[0022] As a further improvement of the above technical solution,

[0023] As a further improvement of the above technical solution, the ratio of the focal length fA of the first negative power lens to the focal length fW of the entire optical system satisfies: -1.5 <fA / fW<-0.75;

[0024] The ratio of the focal length fB of the first positive power triplet lens group to the focal length fW of the entire optical system satisfies: 1.5 <fB / fW<3.6;

[0025] The ratio of the focal length fC of the second positive power triplet lens group to the focal length fW of the entire optical system satisfies: 7.2 <fC / fW<14;

[0026] The ratio of the focal length fD of the fifth positive power lens to the focal length fW of the entire optical system satisfies the following relationship: 2.5 <fD / fW<4.3。

[0027] As a further improvement to the above technical solution, the ratios of the focal length f2 of the second negative power lens, the focal length f3 of the first positive power lens, the focal length f4 of the second positive power lens, and the focal length fB of the first positive power triplet lens group satisfy the following in sequence:

[0028] -3 <f2 / fB<-0.5;

[0029] 0.32 <f3 / fB<2;

[0030] 1.5 <f4 / fB<6.6。

[0031] As a further improvement to the above technical solution, the ratios of the focal length f5 of the third positive power lens, the focal length f6 of the third negative power lens, the focal length f7 of the fourth positive power lens, and the focal length fC of the second positive power triplet lens group satisfy the following in sequence:

[0032] 0.07 <f5 / fC<0.28;

[0033] -0.16 <f6 / fC<-0.04;

[0034] 0.11 <f7 / fC<0.42。

[0035] As a further improvement to the above technical solution, the refractive index n1 of the first negative power lens, the refractive index n3 of the second positive power lens, the refractive index n6 of the third negative power lens, and the refractive index n8 of the fifth positive power lens satisfy the following:

[0036] 1.65 <n1<1.9;

[0037] 1.85 <n3<2.0;

[0038] 1.65 <n6<1.9;

[0039] 1.5 <n8<1.75。

[0040] As a further improvement to the above technical solution, the Abbe number Vd1 of the first negative power lens, the Abbe number Vd4 of the third positive power lens, the Abbe number Vd7 of the third negative power lens, and the Abbe number Vd8 of the fifth positive power lens satisfy the following:

[0041] 30 <Vd1<60;

[0042] 10 <Vd4<50;

[0043] 60 <Vd7<100;

[0044] 50 <Vd8<90。

[0045] The present invention also provides a rigid tube optical microendoscope, comprising the rigid tube optical microendoscope objective lens.

[0046] The beneficial effects of the present invention are as follows: the endoscope objective lens of the present invention is composed of a first negative optical focal length lens, a first positive optical focal length triplet lens group, a second positive optical focal length triplet lens group, and a fifth positive optical focal length lens, which solves the problem of lens miniaturization while improving the imaging quality to 8K. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 1 is a schematic diagram of the optical path of the objective lens of the rigid tube optical microendoscope according to embodiment 1 of the present invention;

[0048] Figure 2 1 is an MTF transfer function diagram of the objective lens of the rigid optical microendoscope according to Example 1 of the present invention;

[0049] Figure 3 is a field curvature diagram of the objective lens of the rigid-tube optical microendoscope according to Example 1 of the present invention;

[0050] Figure 4 1 is a distortion diagram of the objective lens of the rigid tube optical microendoscope according to Example 1 of the present invention;

[0051] Figure 5 Schematic diagram of the optical path of the objective lens of the rigid tube optical microendoscope according to embodiment 2 of the present invention;

[0052] Figure 6 1 is an MTF transfer function diagram of the objective lens of the rigid tube optical microendoscope according to Example 2 of the present invention;

[0053] Figure 7 is a field curvature diagram of the objective lens of the rigid-tube optical microendoscope according to Example 2 of the present invention;

[0054] Figure 8 1 is a distortion diagram of the objective lens of the rigid tube optical microendoscope according to Example 2 of the present invention;

[0055] Figure 9 Schematic diagram of the optical path of the objective lens of the rigid tube optical microendoscope according to embodiment 3 of the present invention;

[0056] Figure 10 1 is an MTF transfer function diagram of the objective lens of the rigid tube optical microendoscope according to Example 3 of the present invention;

[0057] Figure 11 is a field curvature diagram of the objective lens of the rigid-tube optical microendoscope according to Example 3 of the present invention;

[0058] Figure 12 3 is a distortion diagram of the objective lens of the rigid tube optical microendoscope according to Example 3 of the present invention. DETAILED DESCRIPTION

[0059] The present application will be described in further detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0060] The objective lens of the rigid optical microendoscope of this embodiment is provided with a first negative power lens, a first positive power triplet lens group, a second positive power triplet lens group, and a fifth positive power lens in order from the object side to the image side; wherein:

[0061] The first positive power triplet lens group consists of a second negative power lens, a first positive power lens, and a second positive power lens;

[0062] The second positive power triplet lens group consists of a third positive power lens, a third negative power lens and a fourth positive power lens.

[0063] The first negative power lens is a single-group planar meniscus concave lens, wherein the side of the first negative power lens close to the object plane is convex, and the side close to the image plane is concave;

[0064] The second negative power lens is a plano-concave lens, wherein the side of the second negative power lens close to the object plane is flat, and the side close to the image plane is concave;

[0065] The first positive power lens is a biconvex lens, wherein the side of the first positive power lens close to the object plane is convex, and the side close to the image plane is convex;

[0066] The second positive power lens is a meniscus convex lens, the side of the second positive power lens close to the object plane is concave, and the side close to the image plane is convex;

[0067] The third positive power lens is a biconvex lens, wherein the side of the third positive power lens close to the object plane is convex, and the side close to the image plane is convex;

[0068] The third negative power lens is a biconcave lens, wherein the side of the third negative power lens close to the object plane is concave, and the side close to the image plane is concave;

[0069] The fourth positive power lens is a biconvex lens; the fourth positive power lens has a convex surface on the side close to the object plane and a convex surface on the side close to the image plane;

[0070] The fifth positive power single lens is a single-group double-convex lens. The side of the fifth positive power lens close to the object plane is convex, and the side close to the image plane is convex.

[0071] The ratios of the focal length fA of the first negative power meniscus lens, the focal length fB of the first positive power triplet lens group, the focal length fC of the second positive power triplet lens group, the focal length fD of the fifth positive power singlet lens, and the focal length fW of the entire optical system satisfy the following in sequence:

[0072] -1.5 <fA / fW<-0.75;

[0073] 1.5 <fB / fW<3.6;

[0074] 7.2 <fC / fW<14;

[0075] 2 <fD / fW<3。

[0076] The ratios of the focal length f2 of the second negative power lens, the focal length f3 of the first positive power lens, the focal length f4 of the second positive power lens, and the focal length fB of the first positive power triplet lens group satisfy the following in sequence:

[0077] -3 <f2 / fB<-0.5;

[0078] 0.32 <f3 / fB<2;

[0079] 1.5 <f4 / fB<6.6。

[0080] The ratios of the focal length f5 of the third positive power lens, the focal length f6 of the third negative power lens, the focal length f7 of the fourth positive power lens, and the focal length fC of the second positive power triplet lens group satisfy the following in sequence:

[0081] 0.07 <f5 / fC<0.28;

[0082] -0.16 <f6 / fC<-0.04;

[0083] 0.11 <f7 / fC<0.42。

[0084] The refractive index n1 of the first negative power lens, the refractive index n3 of the second positive power lens, the refractive index n6 of the third negative power lens, and the refractive index n8 of the fifth positive power lens satisfy the following:

[0085] 1.65 <n1<1.9;

[0086] 1.85 <n3<2.0;

[0087] 1.65 <n6<1.9;

[0088] 1.5 <n8<1.75。

[0089] The Abbe number Vd1 of the first negative power lens, the Abbe number Vd4 of the third positive power lens, the Abbe number Vd7 of the third negative power lens, and the Abbe number Vd8 of the fifth positive power lens satisfy the following:

[0090] 30 <Vd1<60;

[0091] 10 <Vd4<50;

[0092] 60 <Vd7<100;

[0093] 50 <Vd8<90。

[0094] In order to prove the effect of the objective lens of the present invention, the following specific embodiments are provided for illustration:

[0095] Example 1

[0096] The F number of the objective lens in this embodiment is 2.4, and the objective lens composition is as follows: Figure 1 As shown. The parameter data of the endoscope objective lens is shown in the table below:

[0097]

[0098]

[0099] Depend on Figure 2 From the MTF transfer function diagram, it can be seen that when the modulation index is 0.2, the spatial frequency value of the central field of view can reach above 480lp / mm. Figure 3 and Figure 4 It can be seen that the distortion of the objective lens is less than 3.5%, and the sagittal field curvature and meridional field curvature values ​​are both less than 0.003 mm.

[0100] Example 2

[0101] The F number of the objective lens in this embodiment is 2.4, and the objective lens composition is as follows: Figure 5 As shown. The parameter data of the endoscope objective lens is shown in the table below:

[0102]

[0103]

[0104] Depend on Figure 6 From the MTF transfer function diagram, it can be seen that when the modulation index is 0.2, the spatial frequency value of the central field of view can reach above 480lp / mm. Figure 7 and Figure 8 It can be seen that the distortion of the objective lens is less than 3.04%, and the sagittal field curvature and meridional field curvature values ​​are both less than 0.008 mm.

[0105] Example 3

[0106] The F number of the objective lens in this embodiment is 2.4, and the objective lens composition is as follows: Figure 9 As shown. The parameter data of the endoscope objective lens is shown in the table below:

[0107]

[0108]

[0109] Depend on Figure 10 From the MTF transfer function diagram, it can be seen that when the modulation index is 0.2, the spatial frequency value of the central field of view can reach above 480lp / mm. Figure 11 and Figure 12 It can be seen that the distortion of the objective lens is less than 2.84%, and the sagittal field curvature and meridional field curvature values ​​are both less than 0.009 mm.

[0110] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous improvements without departing from the scope of the present invention, and such improvements are all within the scope of protection of the present invention.

Claims

1. A rigid tube optical microendoscope objective lens, characterized in that: The objective lens has eight lenses with optical power, and is provided with a first negative optical power lens, a first positive optical power triplet lens group, a second positive optical power triplet lens group, and a fifth positive optical power lens in sequence from the object side to the image side; wherein: The first positive power triplet lens group consists of a second negative power lens, a first positive power lens, and a second positive power lens; The second positive power triplet lens group consists of a third positive power lens, a third negative power lens, and a fourth positive power lens; The first negative power lens is a single-group meniscus concave lens, the side of the first negative power lens close to the object plane is convex, and the side close to the image plane is concave; The second negative power lens is a plano-concave lens, wherein the side of the second negative power lens close to the object plane is a flat surface, and the side close to the image plane is a concave surface; The first positive power lens is a biconvex lens, wherein the side of the first positive power lens close to the object plane is convex, and the side close to the image plane is convex; The second positive power lens is a meniscus convex lens, the side of the second positive power lens close to the object plane is concave, and the side close to the image plane is convex; The third positive power lens is a biconvex lens, wherein the side of the third positive power lens close to the object plane is convex, and the side close to the image plane is convex; The third negative power lens is a biconcave lens, wherein the side of the third negative power lens close to the object plane is concave, and the side close to the image plane is concave; The fourth positive power lens is a biconvex lens, wherein the side of the fourth positive power lens close to the object plane is convex, and the side of the fourth positive power lens close to the image plane is convex; The fifth positive power lens is a single-group biconvex lens, wherein the side of the fifth positive power lens close to the object plane is convex, and the side close to the image plane is convex; The ratio of the focal length fA of the first negative power lens to the focal length fW of the entire optical system satisfies: -1.5 <fA / fW<-0.75; The ratio of the focal length fB of the first positive power triplet lens group to the focal length fW of the entire optical system satisfies: 1.5 <fB / fW<3.6; The ratio of the focal length fC of the second positive power triplet lens group to the focal length fW of the entire optical system satisfies: 7.2 <fC / fW<14; The ratio of the focal length fD of the fifth positive power lens to the focal length fW of the entire optical system satisfies the following relationship: 2.5 <fD / fW<4.3; The ratios of the focal length f2 of the second negative power lens, the focal length f3 of the first positive power lens, the focal length f4 of the second positive power lens, and the focal length fB of the first positive power triplet lens group satisfy the following in sequence: -3 <f2 / fB<-0.5; 0.32 <f3 / fB<2; 1.5 <f4 / fB<6.6; The ratios of the focal length f5 of the third positive power lens, the focal length f6 of the third negative power lens, the focal length f7 of the fourth positive power lens, and the focal length fC of the second positive power triplet lens group satisfy the following in sequence: 0.07 <f5 / fC<0.28; -0.16 <f6 / fC<-0.04; 0.11 <f7 / fC<0.42; The refractive index n1 of the first negative power lens, the refractive index n3 of the second positive power lens, the refractive index n6 of the third negative power lens, and the refractive index n8 of the fifth positive power lens satisfy the following: 1.65<n1<1.9； 1.85<n3<2.0； 1.65<n6<1.9； 1.5<n8<1.75； The Abbe number Vd1 of the first negative power lens, the Abbe number Vd4 of the third positive power lens, the Abbe number Vd7 of the third negative power lens, and the Abbe number Vd8 of the fifth positive power lens satisfy the following: 30 <Vd1<60; 10 <Vd4<50; 60 <Vd7<100; 50 <Vd8<90。 2. The rigid tube optical microendoscope objective lens according to claim 1, characterized in that: The F number of the objective lens is 2.

4.

3. A rigid tube optical microendoscope, characterized in that: The invention comprises the rigid tube optical microendoscope objective lens as described in any one of claims 1-2.

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