Variable focal length surgical microscope objective

Abstract

The application discloses a variable focal length surgical microscope objective lens, which comprises a first lens group and a second lens group arranged in sequence along the direction away from the observed object; the first lens group has a negative focal length and comprises a first lens and a second lens; the first lens is a positive lens, the first lens has a first concave spherical surface and a first convex spherical surface; the first concave spherical surface is concave to the observed object, and the first convex spherical surface is convex to the second lens group; the second lens is a negative lens; the focal length of the first lens group is F1, the focal length of the second lens group is F2, and the focal length ratio of the first lens group to the second lens group satisfies the following relationship: 0.93<|F1 / F2|<1.08. The application can provide a larger working distance range under the premise of meeting the magnification requirement, expand the application range, meet the use requirements of more departments of hospitals, and improve the imaging quality.

Description

Technical Field

[0001] The invention relates to a variable-focus surgical microscope objective lens. Background Art

[0002] The surgical microscope objective lens, as a crucial component of the surgical microscope, directly impacts the imaging results. The distance between the surgical microscope objective lens (the spherical vertex of the lens at the front of the lens) and the object being observed is called the working distance. Working distance requirements vary significantly between different departments. For example, hand surgery requires a working distance of 200-300mm; ENT and neurosurgery require 200-500mm; spinal surgery requires 500-600mm; and exoscopic surgery requires a working distance of 650mm. A wider working distance range provides the surgeon with ample operating space and space for various surgical instruments, improving the success rate of surgery. However, to meet magnification requirements, the working distance range is relatively narrow, limiting its scope of application and failing to meet industry requirements. Furthermore, this also affects imaging quality. Summary of the Invention

[0003] In order to overcome the shortcomings of the existing technology, the purpose of the present invention is to provide a variable focal length surgical microscope objective lens, which can provide a larger working distance range while meeting the magnification requirements, expand its scope of application, meet the use requirements of more departments in the hospital, and improve imaging quality.

[0004] The purpose of the present invention is achieved by the following technical solutions:

[0005] A variable focal length surgical microscope objective lens, comprising a first lens group and a second lens group arranged in sequence in a direction away from an object being observed; the first lens group has negative optical power and includes a first lens and a second lens; the first lens is a positive lens, having a first concave spherical surface and a first convex spherical surface; the first concave spherical surface is concave toward the object being observed, and the first convex spherical surface is convex toward the second lens group; the second lens is a negative lens, the second lens group has positive optical power and includes a third lens with positive optical power and a positive cemented unit with positive optical power; the distance d between the first lens group and the second lens group is 0.8 mm <d<27mm,所述第一镜组的焦距为F1,所述第二镜组的焦距为F2,所述第一镜组与第二镜组的焦距比值满足以下关系式:0.93<|F1 / F2|<1.08。

[0006] The second lens has a second concave spherical surface and a third concave spherical surface. The second concave spherical surface is concave toward the object being observed, and the third concave spherical surface is concave toward the second lens group.

[0007] The radius of the second concave spherical surface is the same as the radius of the first convex spherical surface, and the second concave spherical surface is fitted together with the first convex spherical surface.

[0008] -120mm <F1<-101mm。

[0009] The third lens has a second convex spherical surface and a third convex spherical surface, and the radius of the second convex spherical surface is greater than the radius of the third convex spherical surface.

[0010] The second convex spherical surface is convex toward the object being observed, and the third convex spherical surface is convex toward a side of the third lens away from the object being observed.

[0011] The focal length of the third lens is F3, 125mm <F3<170mm。

[0012] The focal length of the positive cemented unit is F4, and the focal length ratio of the positive cemented unit to the third lens satisfies the following relationship: 3.3 <F4 / F3<3.8。

[0013] The positive cemented unit includes a fourth lens with positive optical power and a fifth lens with negative optical power.

[0014] The working distance between the first lens group and the object to be observed is WD, where WD=200 mm to 750 mm.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention provides a variable-focal-length surgical microscope objective lens. Based on the use of a first lens group and a second lens group, the first lens group and the second lens group are reasonably arranged, and the focal length ratio of the first lens group to the second lens group is reasonably set. Thus, while meeting magnification requirements, the objective lens can provide a larger working distance range, expand its scope of application, and meet the working distance requirements of surgical microscopes in more hospital departments. Furthermore, the objective lens has excellent imaging quality and lower cost. Furthermore, the manufacturability of each lens is good, and the entire device can be easily assembled and adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the variable focal length surgical microscope objective lens of the present invention;

[0018] Figure 2 Schematic diagram of the structure of the first mirror group;

[0019] Figure 3 Schematic diagram of the structure of the second mirror group;

[0020] Figure 4 It is a structural diagram of the regulating device;

[0021] Among them, 10, first lens group; 20, first lens; 21, first concave spherical surface; 22, first convex spherical surface; 30, second lens; 31, second concave spherical surface; 32, third concave spherical surface; 40, second lens group; 50, third lens; 51, second convex spherical surface; 52, third convex spherical surface; 60, positive cemented unit; 70, fourth lens; 71, fourth convex spherical surface; 72, fifth convex spherical surface; 80, fifth lens; 81, fourth concave spherical surface; 82, sixth convex spherical surface; 90, adjustment device; 91, mounting seat; 92, screw; 93, screw nut; 94, driving device. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0023] like Figure 1-4 As shown, a variable-focus surgical microscope objective lens includes a first lens group 10 and a second lens group 40 arranged in sequence along a direction away from the object being observed; the first lens group 10 has negative optical power and includes a first lens 20 and a second lens 30; the first lens 20 is a positive lens and has a first concave spherical surface 21 and a first convex spherical surface 22; the first concave spherical surface 21 is concave toward the object being observed, and the first convex spherical surface 22 is convex toward the second lens group 40; the second lens 30 is a negative lens, and the second lens group 40 has positive optical power and includes a third lens 50 with positive optical power and a positive cemented unit 60 with positive optical power; the distance d between the first lens group 10 and the second lens group 40 is 0.8 mm. <d<27mm,所述第一镜组10的焦距为F1,所述第二镜组40的焦距为F2,所述第一镜组10与第二镜组40的焦距比值满足以下关系式:0.93<|F1 / F2|<1.08。在使用时,若F1为-110mm,依据

[0024] 0.93<|F1 / F2|<1.08, then F2 is 101.85-118.27.

[0025] When in use, the light beam emitted by the observed object forms a parallel beam after passing through the variable focal length surgical microscope objective lens, passes through a continuously variable magnification telescopic optical system, and then the binocular tube optical system forms a primary magnified image of the observed object. This image is exactly at the front focal plane of the eyepiece. The eyepiece magnifies it for a second time and then enters the observer's eyes, and the observer finally obtains a magnified image. The present invention provides a variable-focal-length surgical microscope objective lens. Based on the use of a first lens group 10 and a second lens group 40, the first lens group 10 adopts a first lens 20 and a second lens 30. The first lens 20 is configured as a positive lens and is provided with a first concave spherical surface 21 and a first convex spherical surface 22, such that the first concave spherical surface 21 is concave toward the object being observed, and the first convex spherical surface 22 is convex toward the second lens group 40. The second lens group 40 is configured to have positive focal power, and adopts a third lens 50 with positive focal power and a positive cemented unit 60 with positive focal power. Simultaneously, by reasonably setting the focal length ratio of the first lens group 10 to the second lens group 40, a larger working distance range can be provided while meeting magnification requirements, thereby expanding the scope of application and meeting the working distance requirements of surgical microscopes in more hospital departments. Furthermore, imaging quality can be improved.

[0026] In this embodiment, the radius of the first concave spherical surface 21 is 70.51 mm, the refractive index of the first concave spherical surface 21 is 2.0007, and the Abbe number of the first concave spherical surface 21 is 25.43. The radius of the first convex spherical surface 22 is 45.76 mm, the distance between the concave point of the first concave spherical surface 21 and the convex point of the first convex spherical surface 22 is 5.4-5.6 mm, the refractive index of the first convex spherical surface 22 is 1.717, and the Abbe number of the first convex spherical surface 22 is 47.9. The diameter of the first lens 20 is 48 mm to improve image quality and reduce production costs.

[0027] The second lens 30 has a second concave spherical surface 31 and a third concave spherical surface 32. The second concave spherical surface 31 is concave toward the object being observed, and the third concave spherical surface 32 is concave toward the second lens group 40. By adopting the above structure and properly arranging the second lens 30, a wider working distance range can be provided and costs can be reduced.

[0028] The radius of the second concave spherical surface 31 is the same as that of the first convex spherical surface 22, and the second concave spherical surface 31 is bonded to the first convex spherical surface 22. Specifically, the second concave spherical surface 31 and the first convex spherical surface 22 are bonded together by optical glue, so as to facilitate processing and manufacturing.

[0029] In this embodiment, the radius of the third concave spherical surface 32 is 1077.48 mm, the radius of the second concave spherical surface 31 is 45.76 mm, the distance between the concave point of the third concave spherical surface 32 and the concave point of the second concave spherical surface 31 is 3.2-3.4 mm, and the diameter of the second lens 30 is 48 mm, so as to improve the imaging quality and lower the production cost.

[0030] Preferably, -120mm <F1<-101mm。通过合理设置第一镜组10的焦距,可进一步提供更大的工作距离范围。

[0031] The third lens 50 has a second convex surface 51 and a third convex surface 52. The radius of the second convex surface 51 is larger than the radius of the third convex surface 52. The second convex surface 51 is convex toward the object being observed, while the third convex surface 52 is convex toward the side of the third lens 50 away from the object being observed. By adopting this structure for the third lens 50, image quality is improved while also being easier to manufacture and reducing costs.

[0032] The focal length of the third lens 50 is F3, 125mm <F3<170mm。通过合理设置第三透镜50的焦距,可进一步提供更大的工作距离范围。

[0033] In this embodiment, the radius of the second convex spherical surface 51 is 434.81 mm, the refractive index of the second convex spherical surface 51 is 1.4378, the Abbe number of the second convex spherical surface 51 is 94.5, the radius of the third convex spherical surface 52 is 83.3 mm, and the distance between the convex point of the second convex spherical surface 51 and the convex point of the third convex spherical surface 52 is 6.63-6.77 mm. The diameter of the third lens 50 is 48 mm, which improves image quality and reduces production costs.

[0034] The focal length of the positive cemented unit 60 is F4, and the focal length ratio of the positive cemented unit 60 to the third lens 50 satisfies the following relationship: 3.3 <F4 / F3<3.8。通过合理设置正胶合单元60与第三透镜50的焦距比值,可进一步提供更大的工作距离范围。

[0035] The positive cemented unit 60 includes a fourth lens 70 with positive refractive power and a fifth lens 80 with negative refractive power.

[0036] The fourth lens 70 has a fourth convex surface 71 and a fifth convex surface 72. The radius of the fourth convex surface 71 is greater than the radius of the fifth convex surface 72. The fourth convex surface 71 is convex toward the object being observed, while the fifth convex surface 72 is convex toward the side of the fourth lens 70 away from the object being observed. By adopting this structure for the fourth lens 70, image quality is improved while also being easier to manufacture and reducing costs.

[0037] In this embodiment, the radius of the fourth convex spherical surface 71 is 3031.83 mm, the refractive index of the fourth convex spherical surface 71 is 1.6127, the Abbe number of the fourth convex spherical surface 71 is 58.6, the radius of the fifth convex spherical surface 72 is 63.02 mm, the distance between the convex point of the fourth convex spherical surface 71 and the convex point of the fifth convex spherical surface 72 is 7.4-7.6 mm, the refractive index of the fifth convex spherical surface 72 is 1.8503, and the Abbe number of the fifth convex spherical surface 72 is 32.3. The diameter of the fourth lens 70 is 48 mm to improve the imaging quality and lower the production cost.

[0038] The fifth lens 80 has a fourth concave spherical surface 81 and a sixth convex spherical surface 82. The radius of the fourth concave spherical surface 81 is smaller than the radius of the sixth convex spherical surface 82. The fourth concave spherical surface 81 is concave toward the object being observed, while the sixth convex spherical surface 82 is convex toward the side of the fifth lens 80 away from the object being observed. By adopting this structure for the fifth lens 80, image quality is improved while also being easier to manufacture and reducing costs.

[0039] Preferably, the focal length of the positive gluing unit 60 can be set to: 410mm <F4<500mm。

[0040] Specifically, the third lens 50 is located between the first lens group 10 and the positive cementing unit 60, with the third convex spherical surface 52 facing the positive cementing unit 60. The fifth convex spherical surface 72 of the fourth lens 70 and the fourth concave spherical surface 81 have the same radius, and the fifth convex spherical surface 72 of the fourth lens 70 are bonded to the fourth concave spherical surface 81. The fifth convex spherical surface 72 and the fourth concave spherical surface 81 of the fourth lens 70 are bonded together using optical glue, thereby facilitating processing and manufacturing.

[0041] In this embodiment, the radius of the sixth convex spherical surface 82 is 140.24 mm, the radius of the fourth concave spherical surface 81 is 63.02 mm, the distance between the convex point of the sixth convex spherical surface 82 and the concave point of the fourth concave spherical surface 81 is 3.2-3.4 mm, the refractive index of the fourth concave spherical surface 81 is 1.8503, and the Abbe number of the fourth concave spherical surface 81 is 32.3. The diameter of the fifth lens 80 is 48 mm, which improves image quality and reduces manufacturing costs.

[0042] Preferably, the working distance between the first lens group 10 and the object to be observed is WD, WD=200 mm to 750 mm, so as to expand its working distance range.

[0043] Preferably, the variable focal length surgical microscope objective further comprises an adjusting device 90, the adjusting device 90 comprising a mounting base 91, a lead screw 92, a lead screw nut 93, a driving device 94; the first lens group 10 is in sliding fit with the mounting base 91 and is connected with the lead screw nut 93; the lead screw 92 is horizontally arranged and is rotatably mounted on the mounting base 91, the lead screw nut 93 is matchedly sleeved on the lead screw 92, and the driving device 94 is used for driving the lead screw 92 to rotate; in use, when the driving device 94 drives the lead screw 92 to rotate forward, the lead screw nut 93 is driven to move forward to drive the first lens group 10 to move towards the second lens group 40, and when the driving device 94 drives the lead screw 92 to rotate reversely, the lead screw nut 93 is driven to move backward to drive the first lens group 10 to move away from the second lens group 40, so that the distance between the second lens group 40 and the first lens group 10 can be flexibly adjusted.

[0044] Preferably, the driving device 94 comprises a motor, and an output shaft of the motor is connected with the lead screw 92, so as to facilitate the connection.

[0045] The above-mentioned embodiments are only the preferred embodiments of the present application, and cannot be used to limit the protection scope of the present application, and any non-essential changes and replacements made by the person skilled in the art on the basis of the present application shall fall within the protection scope of the present application.

Claims

1. A variable focal length surgical microscope objective lens, characterized in that: It consists of a first lens group and a second lens group arranged in sequence along a direction away from the observed object; the first lens group is movable and has a negative optical power, and the first lens group consists of a first lens and a second lens; the first lens is a positive lens, and the first lens has a first concave spherical surface and a first convex spherical surface; the first concave spherical surface is concave towards the observed object, and the first convex spherical surface bulges towards the second lens group; the second lens is a negative lens, the second lens group has a positive optical power, and consists of a third lens with a positive optical power and a positive cemented unit with a positive optical power; the distance between the first lens group and the second lens group is d, 0.8mm < d < 27mm, the focal length of the first lens group is F1, the focal length of the second lens group is F2, and the ratio of the focal lengths of the first lens group and the second lens group satisfies the following relationship: 0.93 < |F1 / F2| < 1.08; the focal length of the third lens is F3, the focal length of the positive cemented unit is F4, and the ratio of the focal lengths of the positive cemented unit and the third lens satisfies the following relationship: 3.3 < F4 / F3 < 3.8; the positive cemented unit consists of a fourth lens with a positive optical power and a fifth lens with a negative optical power.

2. The variable focal length surgical microscope objective lens according to claim 1, wherein: The second lens has a second concave spherical surface and a third concave spherical surface, the second concave spherical surface is concave towards the observed object, and the third concave spherical surface is concave towards the second lens group.

3. The variable focal length surgical microscope objective lens according to claim 2, wherein: The radius of the second concave spherical surface is the same as the radius of the first convex spherical surface, and the second concave spherical surface is fitted together with the first convex spherical surface.

4. The variable focal length surgical microscope objective lens according to any one of claims 1 to 3, wherein: -120mm < F1 < -101mm.

5. The variable focal length surgical microscope objective lens according to claim 1, wherein: The third lens has a second convex spherical surface and a third convex spherical surface, and the radius of the second convex spherical surface is greater than the radius of the third convex spherical surface.

6. The variable focal length surgical microscope objective lens according to claim 5, wherein: The second convex spherical surface bulges towards the observed object, and the third convex spherical surface bulges towards the side of the third lens away from the observed object.

7. The variable focal length surgical microscope objective lens according to claim 6, wherein: The focal length of the third lens is F3, 125mm < F3 < 170mm.

8. The variable focal length surgical microscope objective lens according to claim 1, wherein: The working distance between the first lens group and the observed object is WD, WD = 200mm to 750mm.

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