CN215006078U

CN215006078U - Medical endoscope optical system

Info

Publication number: CN215006078U
Application number: CN202121140480.3U
Authority: CN
Inventors: 郭毅军; 汤红
Original assignee: Chongqing Xishan Science and Technology Co Ltd
Current assignee: Chongqing Xishan Science and Technology Co Ltd
Priority date: 2021-05-26
Filing date: 2021-05-26
Publication date: 2021-12-03
Anticipated expiration: 2031-05-26

Abstract

The utility model discloses a medical endoscope optical system, which comprises an objective lens group, a rod lens group and an eyepiece lens group which are arranged in sequence from an object side to an image side, wherein the objective lens group comprises a first cemented lens, a second cemented lens and a third single lens, the second cemented lens comprises a second positive lens, a second negative lens and a third positive lens, and the third single lens is a fourth positive lens; the eyepiece includes a fourth cemented lens, a third negative lens, and a fifth positive lens. Because the objective lens group includes first cemented lens, second cemented lens and third single lens, first cemented lens includes first negative lens, plano-crystal lens and first positive lens, the second cemented lens includes second positive lens, second negative lens and third positive lens, the third single lens is the fourth positive lens, the objective lens group adopts the combination of two cemented lenses and a single lens, can eliminate the colour difference, improve resolution ratio, the setting of whole light path can also increase working distance, realize long-range high definition formation of image, medical endoscope optical system's application range has been enlarged.

Description

Medical endoscope optical system

Technical Field

The application relates to the technical field of optical imaging, in particular to a medical endoscope optical system.

Background

The medical endoscope is an endoscope applied to minimally invasive surgery, and comprises a uterine cavity endoscope, an abdominal cavity endoscope, a sinus endoscope and the like, wherein the core of the medical endoscope comprises an optical imaging system and a mechanical structure for supporting the optical imaging system to realize imaging. The optical imaging system consists of an objective lens group, a rod lens group and an ocular lens, is connected with the camera system through an ocular lens end, images to a rear-end image sensor to acquire image information, and magnifies and displays the image information on the display.

The working distance between the object plane of the optical system of the existing medical endoscope and the protective sheet is small, the long-range view is fuzzy, and the application scene range of the medical endoscope is limited.

SUMMERY OF THE UTILITY MODEL

The application provides a medical endoscope optical system, which mainly aims to improve the working distance of the medical endoscope optical system, realize long-range high-definition imaging and further enlarge the application range of a medical endoscope.

In one embodiment, a medical endoscope optical system includes an objective lens group, a rod lens group, and an eyepiece lens group sequentially arranged from an object side to an image side, the objective lens group including a first cemented lens, a second cemented lens, and a third single lens, the first cemented lens including a first negative lens, a plano-crystal lens, and a first positive lens sequentially arranged from the object side to the image side, the second cemented lens including a second positive lens, a second negative lens, and a third positive lens sequentially arranged from the object side to the image side, the third single lens being a fourth positive lens; the eyepiece group comprises a fourth cemented lens, and a third negative lens and a fifth positive lens are sequentially arranged from the object side to the image side of the fourth cemented lens.

In one embodiment, the incident surface and the exit surface of the second positive lens are convex surfaces; the incident surface and the emergent surface of the second negative lens are both concave surfaces, and the incident surface and the emergent surface of the third positive lens are both convex surfaces.

In one embodiment, the incident surface and the exit surface of the fourth positive lens are convex surfaces.

In one embodiment, the incident surface of the first negative lens is a plane, and the emergent surface of the first negative lens is a concave surface; the incident surface of the first positive lens is a plane, and the emergent surface of the first positive lens is a convex surface.

In one embodiment, the working distance of the medical endoscope optical system is 15-30 mm, the diameter of an entrance pupil is larger than 0.14mm, and the magnification is larger than 2.5 times.

In one embodiment, the focal length of the objective lens group is 1-2 mm, and the field angle of the objective lens group is greater than 70 °.

In one embodiment, the magnification of the rod lens group is 1.

In one embodiment, the focal length of the eyepiece group is less than 12 mm.

In one embodiment, the incident surface of the third negative lens is a convex surface, and the exit surface of the third negative lens is a concave surface; and the incident surface and the emergent surface of the fifth positive lens are convex surfaces.

In one embodiment, the medical endoscope optical system further comprises a first protective lens disposed at a front end of the optical path of the objective lens group and a second protective lens disposed at a rear end of the optical path of the eyepiece lens group.

According to the medical endoscope optical system in the above embodiment, the objective lens group includes the first cemented lens, the second cemented lens and the third single lens, the first cemented lens includes the first negative lens, the plano-crystal lens and the first positive lens, the second cemented lens includes the second positive lens, the second negative lens and the third positive lens, the third single lens is the fourth positive lens, and the objective lens group adopts the combination of the two cemented lenses and the single lens, so that chromatic aberration can be eliminated, the resolution ratio can be improved, the working distance can be increased due to the arrangement of the whole optical path, high-definition imaging in a long-range view can be realized, and the application range of the medical endoscope optical system can be enlarged.

Drawings

FIG. 1 is a schematic diagram of an optical system of a medical endoscope according to an embodiment;

FIG. 2 is a schematic diagram of an objective lens assembly according to an embodiment;

FIG. 3 is a schematic diagram of an embodiment of an eyepiece assembly;

FIG. 4 is a plot of the Modulation Transfer Function (MTF) of an optical system in one embodiment;

FIG. 5 is a dot diagram of an optical system in one embodiment.

Detailed Description

The present application will be described in further detail below with reference to the accompanying drawings by way of specific embodiments. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.

Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings). Herein, the end facing the object side is the front end, and the end facing the image side is the rear end.

The embodiment provides a medical endoscope optical system, including but not limited to a uterine cavity endoscope optical system. The optical system has larger optical working distance and can realize long-range high-definition imaging; the image has a larger entrance pupil diameter, the brightness of the image is improved, and the image is prevented from being darker; but also has greater magnification and clarity.

Referring to fig. 1, the optical system of the medical endoscope mainly includes: the optical lens system comprises an objective lens group 1, a rod lens group 2 and an eyepiece lens group 3, wherein the objective lens group 1, the rod lens group 2 and the eyepiece lens group 3 are arranged in sequence from an object side to an image side, and the objective lens group 1, the rod lens group 2 and the eyepiece lens group 3 are aligned on an optical axis. The objective lens group 1 is used for collecting large-field-of-view images and has a large field-of-view angle; the rod lens group 2 is used for transmitting the image formed by the objective lens group 1 to the ocular lens group 3, and the ocular lens group 3 amplifies the image transmitted by the rod lens group 2 and transmits the image to the camera system.

The medical endoscope optical system further comprises a first protective lens 4 and a second protective lens 5, wherein the first protective lens 4 is arranged at the optical front end of the objective lens group 1, the second protective lens 5 is arranged at the optical rear end of the eyepiece lens group 3, and the first protective lens 4 and the second protective lens 5 are respectively arranged at two sides of the imaging lens group. First protective glass piece 4 and second protective glass piece 5 are the plane lens, preferably adopt sapphire glass, and two protective glass pieces mainly play the effect of protection, avoid the foreign matter to enter into imaging lens group, and avoid imaging lens group to be scraped the flower, guarantee imaging lens group's image quality.

Referring to fig. 2, in the present embodiment, the focal length of the objective lens assembly 1 is 1-2 mm, and the field angle of the objective lens assembly 1 is greater than 70 °. The objective lens group 1 includes a first cemented lens 11, a second cemented lens 12 and a third single lens 13, wherein the first cemented lens 11 and the second cemented lens 12 are triple cemented lenses, the third single lens 13 is a single lens, and the first cemented lens 11, the second cemented lens 12 and the third single lens 13 are arranged at a distance from each other.

The first cemented lens 11 includes a first negative lens 111, a plano-crystalline lens 112, and a first positive lens 113, and the first negative lens 111, the plano-crystalline lens 112, and the first positive lens 113 are arranged in order from the object side to the image side. The first negative lens 111 is a plano-concave lens, the incident surface of the first negative lens 111 is a plane, the emergent surface of the first negative lens 111 is a concave surface, the radius of curvature of the concave surface is small, so that the first negative lens 111 has negative focal power, and the first negative lens 111 adopts a high-refractive-index material to realize large-field light collection. The optical lens 112 is a planar lens, the incident surface and the exit surface of the optical lens 112 are both planar, and the optical lens 112 is used for realizing different viewing angles. The first positive lens 113 is a plano-convex lens, the incident surface of the first positive lens 113 is a plane, the exit surface of the first positive lens 113 is a convex surface, the first positive lens 113 has positive focal power, and the first positive lens 113 is used for better converging light rays to ensure a proper real image surface position.

The second cemented lens 12 includes a second positive lens 121, a second negative lens 122, and a third positive lens 123, and the second positive lens 121, the second negative lens 122, and the third positive lens 123 are arranged in order from the object side to the image side. The second positive lens 121 is a biconvex lens, and both the incident surface and the exit surface of the second positive lens 121 are convex surfaces. The second negative lens 122 is a biconcave lens, and both the incident surface and the exit surface of the second negative lens 122 are concave surfaces. The third positive lens 123 is also a biconvex lens, and both the incident surface and the exit surface of the third positive lens 123 are convex surfaces.

The third single lens 13 is a biconvex lens, i.e., a positive lens, and has a positive focal power, and both the incident surface and the exit surface of the third single lens 13 are convex surfaces.

Wherein the second cemented lens 12 and the third single lens 13 are used for eliminating chromatic aberration and balancing the aberration of the system.

The rod lens group 2 is formed by connecting a plurality of same rod lens groups in series, the magnification of the whole rod lens group 2 is 1, and the rod lens group 2 mainly plays a role of transmitting images and transmits the images formed by the objective lens group 1 to the eyepiece lens group 3.

Referring to fig. 3, the eyepiece group 3 includes a fourth cemented lens, which is a double-cemented lens, the fourth cemented lens includes a third negative lens 31 and a fifth positive lens 32, and the third negative lens 31 and the fifth positive lens 32 are sequentially arranged from the object side to the image side. The third negative lens 31 is a meniscus lens, the incident surface of the third negative lens 31 is a convex surface, the exit surface of the third negative lens 31 is a concave surface, and the third negative lens 31 has negative refractive power. The fifth positive lens 32 is a biconvex lens, and both the incident surface and the exit surface of the fifth positive lens 32 are convex surfaces, and the fifth positive lens 32 has positive power. The focal length of the ocular group 3 is less than 12mm, and the ocular group 3 is designed into an object space telecentric optical path, so that the ocular group 3 can be better connected with the optical paths of the objective group 1 and the rod lens group 2.

Referring to fig. 4 and 5, fig. 4 is a Modulation Transfer Function (MTF) curve, the abscissa is a line-pair number of resolution, the ordinate is a contrast value of MTF, fig. 5 is a point diagram, and the Modulation Transfer Function (MTF) curve and the point diagram are important indicators of the imaging quality of the optical system. As can be seen from fig. 4, in the optical system, when the resolution satisfies 100lp/mm, the contrast value of the full field of view is greater than 0.2 and is close to the diffraction limit, which indicates that the imaging quality of the optical system is better. As can be seen from fig. 5, the circle in the graph is an airy disk, the black area in the circle is a diffuse disk, the diffuse disks in the dot-column diagram are all smaller than the airy disk, that is, the diameters of the light spots are all contained in the airy disk and are basically at the diffraction limit, which also shows that the imaging quality of the optical system is better.

In the embodiment, the working distance of the optical system is 15-30 mm, the working distance is large, and long-range high-definition imaging can be achieved. The diameter of the entrance pupil of the optical system is larger than 0.14mm, so that the phenomenon of dark images can be improved. The F/# is less than 11, when the resolution meets 100lp/mm, the full-field contrast value is more than 0.2, the resolution is higher, and the imaging quality is better. The focal length of the objective lens group 1 is 1-2 mm, the focal length of the ocular lens group is less than 12mm, and the magnification of the optical system is more than 2.5 times and has a larger magnification. Therefore, the medical endoscope optical system can meet the requirements of more use scenes.

The present application has been described with reference to specific examples, which are provided only to aid understanding of the present application and are not intended to limit the present application. For a person skilled in the art to which the application pertains, several simple deductions, modifications or substitutions may be made according to the idea of the application.

Claims

1. The medical endoscope optical system is characterized by comprising an objective lens group, a rod lens group and an eyepiece lens group which are sequentially arranged from an object side to an image side, wherein the objective lens group comprises a first cemented lens, a second cemented lens and a third single lens; the eyepiece group comprises a fourth cemented lens, and a third negative lens and a fifth positive lens are sequentially arranged from the object side to the image side of the fourth cemented lens.

2. The medical endoscope optical system according to claim 1, wherein the incident surface and the exit surface of the second positive lens are convex surfaces; the incident surface and the emergent surface of the second negative lens are both concave surfaces, and the incident surface and the emergent surface of the third positive lens are both convex surfaces.

3. The medical endoscope optical system according to claim 1, wherein the incident surface and the exit surface of the fourth positive lens are convex surfaces.

4. The medical endoscope optical system according to claim 1, wherein the incident surface of the first negative lens is a flat surface, and the exit surface is a concave surface; the incident surface of the first positive lens is a plane, and the emergent surface of the first positive lens is a convex surface.

5. The medical endoscope optical system according to claim 1, wherein the working distance of the medical endoscope optical system is 15 to 30mm, the diameter of the entrance pupil is more than 0.14mm, and the magnification is more than 2.5 times.

6. The medical endoscope optical system according to claim 1, wherein a focal length of the objective lens group is 1 to 2mm, and a field angle of the objective lens group is larger than 70 °.

7. The medical endoscope optical system according to claim 1, wherein the magnification of said rod lens group is 1.

8. The medical endoscope optical system according to claim 1, wherein a focal length of said eyepiece group is less than 12 mm.

9. The medical endoscope optical system according to claim 8, wherein the third negative lens has a convex incident surface and a concave exit surface; and the incident surface and the emergent surface of the fifth positive lens are convex surfaces.

10. The medical endoscope optical system according to claim 1, further comprising a first protective lens disposed at an optical path front end of the objective lens group and a second protective lens disposed at an optical path rear end of the eyepiece lens group.