Eye objective lens for ultra-wide-angle fundus color imaging

Abstract

A simple optical structure is adopted, the eye objective lens adopts a combination of a meniscus lens and a group of glued lenses to realize large-view-field fundus imaging, the lens weight is reduced due to the small number of lenses, stray light caused by lens surface reflection is reduced, the glued surface of the eye objective lens is a spherical surface, and the visual field of the eye objective lens is improved. Gluing and processing of the balsaming lens are facilitated. The aspheric surface profile designed in the invention does not have retroflexion, and is easy to process and detect; and the light path trend does not have large turning, the tolerance is large, and the assembly is easy. According to the invention, the working distance is long, so that the comfort of a patient during shooting can be ensured; the resolution ratio is high, and the fundus resolution ratio is about 10 [mu] m; image distance / focal distance gt; and 0.6, stray light caused by lens surface emission can be reduced. Under the condition that high resolution and human eye comfort are guaranteed, the fundus imaging range is further enlarged, a 110-degree image space large view field can be provided, and a 165-degree ultra-wide-angle imaging view field corresponding to the fundus can be provided.

Description

Technical Field

[0001] The invention relates to the technical field of fundus imaging, and in particular to an eyepiece objective lens used for ultra-wide-angle fundus color imaging. Background Art

[0002] Retinal diseases are the third leading cause of blindness in the world (WHO 2024). The 2024 Global Eye Health Report shows that approximately 230 million people worldwide suffer from retinal diseases, which seriously threaten human visual health. They not only cause varying degrees of visual impairment, but can even cause blindness. Clinically, vascular lesions, infantile eye diseases, retinal tears and detachments are common diseases. These diseases often appear in the peripheral area of ​​the retina in the early stages, and then gradually affect the mid-periphery and posterior pole.

[0003] Traditional fundus imaging technology has significant limitations. It can only capture a 20°-60° fundus area and can effectively display two important fundus areas, the retina and the macula, which are mainly concentrated in the posterior pole (accounting for 30%-40% of the total retinal area). However, early lesions occur in the mid-peripheral and peripheral areas. Traditional fundus cameras cannot capture the lesion area, resulting in a missed diagnosis rate of up to 34% (2024 "Ophthalmology Clinical Data Annual Report"), and missing the opportunity to detect and treat patients early.

[0004] In recent years, based on ultra-wide-angle imaging technology, there have been major breakthroughs in increasing the field of fundus imaging. Fundus imaging equipment with a 90° field of view has emerged, and the shooting area basically covers the posterior pole and the mid-periphery, but the far peripheral area of ​​the retina cannot be observed. However, early lesion detection in this area is extremely important. The detection rate of neovascularization in the far peripheral vortex vein area in diabetic retinopathy is 2.6 times that of the mid-periphery; the rate of retinal thinning in the far peripheral area in high myopia peripheral degeneration is as high as 73%; retinal holes near the vortex vein exit point account for 68% of all holes.

[0005] Therefore, pursuing a larger fundus imaging field of view is still an important development direction of fundus imaging. Ultra-wide-angle imaging of the fundus can be performed by scanning imaging. Ultra-wide-angle fundus imaging equipment can obtain fundus images with a large field of view through a single non-mydriatic shooting, which optimizes the process of ophthalmic diagnosis and improves diagnostic efficiency. The eyepiece objective is a key component of ultra-wide-angle fundus imaging. It has a large imaging field of view, and the pupil is located in front of the eyepiece objective. The working distance between the pupil and the eyepiece objective is required to be as large as possible. These put forward high requirements on the design of the eyepiece objective. Summary of the invention

[0006] In order to achieve the above-mentioned purpose and other advantages of the present invention, the purpose of the present invention is to provide an eyepiece objective lens for ultra-wide-angle fundus color imaging, comprising an eyepiece objective lens single-piece lens and an eyepiece objective lens cemented lens, wherein the eyepiece objective lens single-piece lens and the eyepiece objective lens cemented lens are arranged in sequence from the pupil side to the image plane side;

[0007] The eyepiece objective single-piece lens is a meniscus lens, the concave surface of the meniscus lens is a spherical surface and faces the pupil, and the convex surface of the meniscus lens is an aspherical surface;

[0008] The eyepiece-objective lens is glued together in sequence from the pupil side to the image side by a first aspheric lens, a biconcave lens, and a second aspheric lens;

[0009] The first aspheric lens is a biconvex lens, the non-gluing surface and gluing surface of the first aspheric lens are aspheric and spherical respectively, the gluing surfaces on both sides of the biconcave lens are spherical, and the second aspheric lens is a biconvex lens, the gluing surface and non-gluing surface of the second aspheric lens are spherical and aspherical respectively.

[0010] Furthermore, the relationship between the eye-object image distance and the focal length is: 0.6<image distance / focal length<1.

[0011] Furthermore, the curvature radius of the concave surface of the meniscus lens is -40 to -42 mm, and the net aperture of the concave surface of the meniscus lens is 20 to 22 mm.

[0012] Furthermore, the convex surface of the meniscus lens is a standard second-order aspheric surface, the radius of curvature of the convex surface of the meniscus lens is -20 to -22 mm, the net aperture of the convex surface of the meniscus lens is 23 to 25 mm, and the conic coefficient of the convex surface of the meniscus lens is -0.34 to -0.36.

[0013] Furthermore, the center thickness of the eyepiece objective single lens is 13-15 mm.

[0014] Furthermore, the net aperture of the eyepiece objective cemented lens is 38-40 mm.

[0015] Furthermore, the non-glued surface of the first aspheric lens is a standard secondary aspheric surface, the curvature radius of the non-glued surface of the first aspheric lens is 67 to 69 mm, the cone coefficient of the non-glued surface of the first aspheric lens is -28 to -30, the curvature radius of the gluing surface of the first aspheric lens is -64 to -66 mm, and the center thickness of the first aspheric lens is 16 to 18 mm.

[0016] Furthermore, the curvature radius of the bonding surface of the biconcave lens close to the pupil side is -64 to -66 mm, the curvature radius of the bonding surface of the biconcave lens away from the pupil side is 100 to 102 mm, and the center thickness of the biconcave lens is 4 to 5 mm.

[0017] Furthermore, the radius of curvature of the bonding surface of the second aspheric lens is 100-102 mm, the non-bonded surface of the second aspheric lens is a high-order even-order aspheric surface, the radius of curvature of the non-bonded surface of the second aspheric lens is infinite, the cone coefficient of the non-bonded surface of the second aspheric lens is 0, the fourth-order term of the non-bonded surface of the second aspheric lens is -5.296E-06, the sixth-order term of the non-bonded surface of the second aspheric lens is 3.885E-09, the eighth-order term of the non-bonded surface of the second aspheric lens is -2E-12, the tenth-order term of the non-bonded surface of the second aspheric lens is 4.338E-16, and the center thickness of the second aspheric lens is 15-16 mm.

[0018] Furthermore, the center distance between the convex surface of the eyepiece objective lens and the non-cemented surface of the first aspherical lens is 0.3 to 0.5.

[0019] Furthermore, the refractive index Nd of the eyepiece objective single lens satisfies 1.6<Nd<1.8, and the Abbe number Vd satisfies 52<Vd<54, the refractive index Nd of the first aspheric lens satisfies 1.7<Nd<1.9, and the Abbe number Vd satisfies 45<Vd<47, the refractive index Nd of the biconcave lens satisfies 1.9<Nd<2.1, and the Abbe number Vd satisfies 17<Vd<19, and the refractive index Nd of the second aspheric lens satisfies 1.8<Nd<2, and the Abbe number Vd satisfies 40<Vd<42.

[0020] Furthermore, the eyepiece objective lens single lens and the eyepiece objective lens cemented lens are made of glass material.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] An eyepiece objective lens for ultra-wide-angle fundus color imaging

[0023] The present invention adopts a simple optical structure. The eyepiece lens adopts a combination of a meniscus lens and a group of cemented lenses to achieve large-field fundus imaging. The small number of lenses not only reduces the weight of the lens, but also reduces the stray light caused by the reflection of the lens surface. The eyepiece lens adopts a spherical surface on the cemented surface, which is conducive to the cementation and processing of the cemented lens. The aspheric surface designed in the present invention does not have a recurve, and is easy to process and detect. In the present invention, the direction of the optical path does not have a large turn, the tolerance is large, and it is easy to assemble.

[0024] The present invention has a longer working distance (the distance from the eyepiece to the pupil), which can ensure the comfort of the patient when photographing the patient. The present invention has a higher resolution, and the fundus resolution is about 10um. The image distance / focal length of the present invention is greater than 0.6, which can reduce the stray light caused by the lens surface emission.

[0025] While ensuring high resolution and human eye comfort, the present invention further increases the range of fundus imaging, and can provide a large image field of view of 110°, corresponding to an ultra-wide-angle imaging field of view of 165° for the fundus.

[0026] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0028] Figure 1 A schematic diagram of an eyepiece objective lens for ultra-wide-angle fundus color imaging;

[0029] Figure 2 is a spot diagram;

[0030] Figure 3 is the MTF graph;

[0031] Figure 4 The distortion map.

[0032] In the figure: 1, single lens of eyepiece objective lens; 2, cemented lens of eyepiece objective lens; 21, first aspheric lens; 22, biconcave lens; 23, second aspheric lens. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the drawings, the shapes and dimensions may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like components.

[0035] In the following description, words such as center, thickness, height, length, front, back, rear, left, right, top, bottom, upper, lower, etc. are defined relative to the structure shown in the drawings. In particular, "height" is equivalent to the dimension from top to bottom, "width" is equivalent to the dimension from left to right, and "depth" is equivalent to the dimension from front to back. They are relative concepts and may change accordingly according to their different positions and different usage states. Therefore, these or other directions should not be interpreted as restrictive terms.

[0036] Terms related to attachment, coupling, and the like (eg, "connected" and "attached") refer to either a fixed or attached relationship between structures, either directly or indirectly, and either movable or rigid attachments or relationships, unless expressly stated otherwise, of the structures to one another through intermediate structures.

[0037] Example 1

[0038] An eyepiece objective lens for ultra-wide-angle fundus color imaging can be used for 110° wide-field fundus imaging, and realizes ultra-wide-angle fundus imaging through reasonable optical structure design. Figure 1 As shown, the eyepiece objective lens includes an eyepiece objective lens single-piece lens 1 and an eyepiece objective lens cemented lens 2, and the eyepiece objective lens single-piece lens and the eyepiece objective lens cemented lens are arranged in sequence from the pupil side to the image side; that is, the eyepiece objective lens single-piece lens 1 is located on the side close to the pupil, and the eyepiece objective lens cemented lens 2 is located on the side away from the pupil.

[0039] The eyepiece objective single-piece lens is a meniscus lens, the concave surface of the meniscus lens is a spherical surface and faces the pupil, and the convex surface of the meniscus lens is an aspherical surface;

[0040] The eye-objective lens cemented lens 2 is glued in sequence from the pupil side to the image side by a first aspheric lens 21, a biconcave lens 22, and a second aspheric lens 23; that is, the eye-objective lens cemented lens 2 is glued by two aspheric lenses (i.e., the first aspheric lens 21 and the second aspheric lens 23) and a biconcave lens 22; among them, the first aspheric lens 21 of the eye-objective lens cemented lens 2 is close to the pupil of the human eye, the middle one is the middle biconcave lens 22 of the eye-objective lens cemented lens 2, and the second aspheric lens 23 of the eye-objective lens cemented lens 2 is far from the pupil of the human eye.

[0041] The first aspheric lens is a biconvex lens, the non-gluing surface and gluing surface of the first aspheric lens are aspheric and spherical respectively, the gluing surfaces on both sides of the biconcave lens are spherical, and the second aspheric lens is a biconvex lens, the gluing surface and non-gluing surface of the second aspheric lens are spherical and aspherical respectively.

[0042] In some embodiments, the focal length of the eyepiece objective is 28-32 mm, the field of view is 114°, the working distance (the distance between the eyepiece objective and the pupil) is 21 mm, the image distance is 13-15 mm, the eyepiece objective is image-square telecentric, and the telecentricity of each field of view is <0.3%. The long working distance can ensure the comfort of the human eye when the eyepiece objective is used, and the relationship between the image distance and the focal length is: 0.6 < image distance / focal length <1, which can reduce the stray light caused by the reflection of the eyepiece objective surface.

[0043] In some embodiments, the curvature radius of the concave surface of the meniscus lens is -40 to -42 mm, and the net aperture of the concave surface of the meniscus lens is 20 to 22 mm. Further, the convex surface of the meniscus lens is a standard second-order aspheric surface, the curvature radius of the convex surface of the meniscus lens is -20 to -22 mm, the net aperture of the convex surface of the meniscus lens is 23 to 25 mm, and the conic coefficient of the convex surface of the meniscus lens is -0.34 to -0.36. Further, the center thickness of the eyepiece single-piece lens is 13 to 15 mm.

[0044] In some embodiments, the net aperture of the eyepiece objective lens is 38 to 40 mm. Further, the non-cemented surface of the first aspheric lens is a standard secondary aspheric surface, the non-cemented surface curvature radius of the first aspheric lens is 67 to 69 mm, the non-cemented surface cone coefficient of the first aspheric lens is -28 to -30, the cemented surface curvature radius of the first aspheric lens is -64 to -66 mm, and the center thickness of the first aspheric lens is 16 to 18 mm.

[0045] Furthermore, the curvature radius of the bonding surface of the biconcave lens close to the pupil side is -64 to -66 mm, the curvature radius of the bonding surface of the biconcave lens away from the pupil side is 100 to 102 mm, and the center thickness of the biconcave lens is 4 to 5 mm.

[0046] Furthermore, the radius of curvature of the bonding surface of the second aspheric lens is 100-102 mm, the non-bonded surface of the second aspheric lens is a high-order even-order aspheric surface, the radius of curvature of the non-bonded surface of the second aspheric lens is infinite, the cone coefficient of the non-bonded surface of the second aspheric lens is 0, the fourth-order term of the non-bonded surface of the second aspheric lens is -5.296E-06, the sixth-order term of the non-bonded surface of the second aspheric lens is 3.885E-09, the eighth-order term of the non-bonded surface of the second aspheric lens is -2E-12, the tenth-order term of the non-bonded surface of the second aspheric lens is 4.338E-16, and the center thickness of the second aspheric lens is 15-16 mm.

[0047] Furthermore, the center distance between the convex surface of the eyepiece objective lens and the non-cemented surface of the first aspherical lens is 0.3 to 0.5.

[0048] Furthermore, the refractive index Nd of the eyepiece objective single lens satisfies 1.6<Nd<1.8, and the Abbe number Vd satisfies 52<Vd<54, the refractive index Nd of the first aspheric lens satisfies 1.7<Nd<1.9, and the Abbe number Vd satisfies 45<Vd<47, the refractive index Nd of the biconcave lens satisfies 1.9<Nd<2.1, and the Abbe number Vd satisfies 17<Vd<19, and the refractive index Nd of the second aspheric lens satisfies 1.8<Nd<2, and the Abbe number Vd satisfies 40<Vd<42.

[0049] In some preferred embodiments, the eyepiece objective lens and the eyepiece objective lens are made of glass. It should be noted that the eyepiece objective lens and the eyepiece objective lens can also be made of other materials such as plastic according to actual needs.

[0050] In one embodiment, the relevant parameters of each lens in the ultra-wide-angle eyepiece objective lens include the radius of curvature, thickness, clear aperture, center spacing, refractive index and Abbe number of the material, as shown below:

[0051] The radius of curvature of the concave surface of the eyepiece objective single-piece lens 1 is -41 mm;

[0052] The radius of curvature of the convex surface of the eyepiece objective single-piece lens 1 is -21.5 mm;

[0053] The radius of curvature of the non-cemented surface of the first aspherical lens 21 of the eyepiece objective cemented lens 2 is 68 mm;

[0054] The curvature radius of the cemented surface of the first aspheric lens 21 of the eyepiece objective cemented lens 2 is -65 mm;

[0055] The radius of curvature of the cemented surface of the biconcave lens 22 of the eyepiece objective cemented lens 2 close to the pupil side is -65mm;

[0056] The radius of curvature of the cemented surface of the biconcave lens 22 of the eyepiece objective cemented lens 2 away from the pupil side is 100 mm;

[0057] The curvature radius of the cemented surface of the second aspheric lens 23 of the eyepiece objective cemented lens 2 is 100 mm;

[0058] The radius of curvature of the non-cemented surface of the second aspherical lens 23 of the eyepiece objective cemented lens 2 is infinite;

[0059] The center thickness of the eyepiece single lens 1 is 15 mm;

[0060] The center thickness of the first aspherical lens 21 of the eyepiece objective cemented lens 2 is 17 mm;

[0061] The center thickness of the biconcave lens 22 of the eyepiece objective lens cemented lens 2 is 4.5 mm;

[0062] The center thickness of the second aspherical lens 23 of the eyepiece objective lens cemented lens 2 is 17 mm;

[0063] The net aperture of the concave surface of the eyepiece objective single-piece lens 1 is 21.618 mm;

[0064] The net diameter of the convex surface of the eyepiece objective single lens 1 is 24.05 mm;

[0065] The net aperture of the non-cemented surface of the first aspherical lens 21 of the eyepiece objective lens cemented lens 2 is 34.35 mm;

[0066] The net aperture of the cemented surface of the first aspheric lens 21 of the eyepiece objective cemented lens 2 is 34.7 mm;

[0067] The net diameter of the biconcave lens 22 of the eyepiece objective lens cemented lens 2 near the pupil side is 34.7 mm;

[0068] The net diameter of the biconcave lens 22 of the eyepiece objective lens cemented lens 2, which is away from the pupil side, is 38.5 mm;

[0069] The net aperture of the cemented surface of the second aspheric lens 23 of the eyepiece objective cemented lens 2 is 38.5 mm;

[0070] The net aperture of the non-cemented surface of the second aspherical lens 23 of the eyepiece objective lens cemented lens 2 is 39.15 mm;

[0071] The center distance between the convex surface of the eyepiece objective single lens 1 and the non-cemented surface of the first aspherical lens 21 of the eyepiece objective cemented lens 2 is 0.4 mm;

[0072] The refractive index of the single lens 1 of the eyepiece objective is 1.76, and the Abbe number is 52.3;

[0073] The first aspherical lens 21 of the eyepiece objective cemented lens 2 has a refractive index of 1.82 and an Abbe number of 46.6;

[0074] The biconcave lens 22 of the eyepiece-objective cemented lens 2 has a refractive index of 1.96 and an Abbe number of 17.5;

[0075] The second aspherical lens 23 of the eyepiece objective cemented lens 2 has a refractive index of 1.88 and an Abbe number of 40.8.

[0076] The image side field angle of the eyepiece objective is designed to be 110°, but the actual value is 114°, corresponding to a fundus imaging angle of 165°.

[0077] Figure 2 , Figure 3The point diagram and MTF diagram of the present invention have good image quality, close to the diffraction limit, indicating that the eyepiece objective has good imaging quality.

[0078] Figure 4 This is a distortion diagram of the present invention. The maximum distortion of the present invention is 15.9%. In a large field of view imaging lens, the distortion is relatively small.

[0079] The number of devices and processing scales described here are used to simplify the description of the present invention. Applications, modifications and variations of the present invention will be obvious to those skilled in the art.

[0080] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

[0081] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0082] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0083] The above description is only an embodiment of this specification and is not intended to limit one or more embodiments of this specification. For those skilled in the art, one or more embodiments of this specification may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of one or more embodiments of this specification shall be included in the scope of the claims of one or more embodiments of this specification.

Claims

1. An eyepiece lens for ultra-wide-angle fundus color imaging, comprising an eyepiece lens single lens and an eyepiece lens cemented lens, characterized in that : the eyepiece objective single lens and the eyepiece objective cemented lens are arranged in sequence from the pupil side to the image plane side; The eyepiece objective single-piece lens is a meniscus lens, the concave surface of the meniscus lens is a spherical surface and faces the pupil, and the convex surface of the meniscus lens is an aspherical surface; The eyepiece-objective lens is glued together in sequence from the pupil side to the image side by a first aspheric lens, a biconcave lens, and a second aspheric lens; The first aspheric lens is a biconvex lens, the non-gluing surface and gluing surface of the first aspheric lens are aspheric and spherical respectively, the gluing surfaces on both sides of the biconcave lens are spherical, and the second aspheric lens is a biconvex lens, the gluing surface and non-gluing surface of the second aspheric lens are spherical and aspherical respectively.

2. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 1, characterized in that: The relationship between the image distance of the eyepiece and the focal length is: 0.6<image distance / focal length<1.

3. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 1, characterized in that: The curvature radius of the concave surface of the meniscus lens is -40 to -42 mm, and the net aperture of the concave surface of the meniscus lens is 20 to 22 mm.

4. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 3, characterized in that: The convex surface of the meniscus lens is a standard second-order aspheric surface, the radius of curvature of the convex surface of the meniscus lens is -20 to -22 mm, the net aperture of the convex surface of the meniscus lens is 23 to 25 mm, and the conic coefficient of the convex surface of the meniscus lens is -0.34 to -0.

36.

5. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 4, characterized in that: The center thickness of the eyepiece objective lens is 13-15 mm.

6. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 1, characterized in that: The net aperture of the eyepiece objective lens is 38-40 mm.

7. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 6, characterized in that: The non-bonded surface of the first aspheric lens is a standard secondary aspheric surface, the curvature radius of the non-bonded surface of the first aspheric lens is 67 to 69 mm, the cone coefficient of the non-bonded surface of the first aspheric lens is -28 to -30, the curvature radius of the bonding surface of the first aspheric lens is -64 to -66 mm, and the center thickness of the first aspheric lens is 16 to 18 mm.

8. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 6, characterized in that: The curvature radius of the bonding surface of the biconcave lens close to the pupil side is -64 to -66 mm, the curvature radius of the bonding surface of the biconcave lens away from the pupil side is 100 to 102 mm, and the center thickness of the biconcave lens is 4 to 5 mm.

9. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 6, characterized in that: The radius of curvature of the bonding surface of the second aspheric lens is 100-102 mm, the non-bonded surface of the second aspheric lens is a high-order even-order aspheric surface, the radius of curvature of the non-bonded surface of the second aspheric lens is infinite, the cone coefficient of the non-bonded surface of the second aspheric lens is 0, the fourth-order term of the non-bonded surface of the second aspheric lens is -5.296E-06, the sixth-order term of the non-bonded surface of the second aspheric lens is 3.885E-09, the eighth-order term of the non-bonded surface of the second aspheric lens is -2E-12, the tenth-order term of the non-bonded surface of the second aspheric lens is 4.338E-16, and the center thickness of the second aspheric lens is 15-16 mm.

10. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 7, characterized in that: The center distance between the convex surface of the eyepiece objective lens and the non-cemented surface of the first aspherical lens is 0.3 to 0.

5.

11. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 1, characterized in that: The refractive index Nd of the eyepiece objective single lens satisfies 1.6<Nd<1.8, and the Abbe number Vd satisfies 52<Vd<54. The refractive index Nd of the first aspheric lens satisfies 1.7<Nd<1.9, and the Abbe number Vd satisfies 45<Vd<47. The refractive index Nd of the biconcave lens satisfies 1.9<Nd<2.1, and the Abbe number Vd satisfies 17<Vd<19. The refractive index Nd of the second aspheric lens satisfies 1.8<Nd<2, and the Abbe number Vd satisfies 40<Vd<42.

12. The eyepiece objective lens for ultra-wide-angle fundus color imaging according to claim 1, characterized in that: The eyepiece objective lens single-piece lens and the eyepiece objective lens cemented lens are made of glass material.

Images