Operating microscope objective lens with variable focal length

Abstract

The invention discloses a variable-focus operating microscope objective lens which comprises a first lens group and a second lens group which are sequentially arranged in the direction away from an observed object. The first lens group has negative focal power and comprises a first lens and a second lens; the first lens is a positive lens and is provided with a first concave spherical surface and a first convex spherical surface; the first concave spherical surface is concave towards an observed object, and the first convex spherical surface is convex towards 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 meets the following relational expression: 0.93 lt; f1 / F2lt; 1.08). On the premise that the magnification requirement is met, a larger working distance range can be provided, the application range is expanded, the use requirements of more departments of a hospital are met, and the imaging quality can be improved.

Description

Technical Field

[0001] The present invention relates to a variable focal length surgical microscope objective lens. Background Art

[0002] As an important part of a surgical microscope, the surgical microscope objective lens directly affects the forming effect. The distance between the surgical microscope objective lens (the spherical vertex of the frontmost lens of the objective lens) and the object to be observed is called the working distance. When the surgical microscope is used in different departments, the requirements for the working distance vary greatly. For example, the working distance required for hand surgery is 200 - 300 mm; for ENT and neurosurgery, it is 200 - 500 mm; for spinal surgery, it is 500 - 600 mm; for an exoscope, a working distance of 650 mm is appropriate. Among them, a larger working distance range can provide doctors with a sufficiently large operating space and accommodate various surgical instruments, improving the success rate of surgery. However, in order to meet the requirements of magnification, the working distance range is relatively narrow, resulting in a relatively limited scope of application and being unable to meet industry requirements. Moreover, it also affects the imaging quality. Summary of the Invention

[0003] In order to overcome the deficiencies of the prior art, 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 on the premise of meeting the magnification requirements, expand its scope of application, meet the usage requirements of more departments in the hospital, and also improve the imaging quality.

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

[0005] A variable focal length surgical microscope objective lens includes a first lens group and a second lens group arranged in sequence along the direction away from the object to be observed; the first lens group has a negative optical power and includes 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 object to be observed, and the first convex spherical surface protrudes towards the second lens group; the second lens is a negative lens, the second lens group has a positive optical power and includes 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, 0.8 mm < d < 27 mm, 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.

[0006] The second lens has a second concave spherical surface and a third concave spherical surface, the second concave spherical surface is concave towards the object to be observed, and the third concave spherical surface is concave towards 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 attached to 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 observed object, and the third convex spherical surface is convex toward a side of the third lens away from the observed object.

[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, WD=200mm-750mm.

[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. On the basis of adopting a first lens group and a second lens group, the first lens group and the second lens group are reasonably set, and the focal length ratio of the first lens group to the second lens group is reasonably set. Under the premise of meeting the magnification requirement, a larger working distance range is provided, and its application scope is expanded to meet the use requirements of more departments of the hospital for the working distance of the surgical microscope; moreover, the imaging quality is excellent and the cost is lower; in addition, the processability of each lens is good, and the whole machine is easy to assemble and adjust. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the variable focal length surgical microscope objective lens of the present invention;

[0018] Figure 2 is a schematic structural diagram of the first mirror group;

[0019] Figure 3 is a schematic structural diagram of the second mirror group;

[0020] Figure 4 is a schematic diagram of the structure of the regulating device;

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

[0022] Next, in combination with the accompanying drawings and the specific implementation manners, the present invention will be further described. It should be noted that, on the premise of no conflict, any combination of the following-described embodiments or technical features can form a new embodiment.

[0023] As Figure 1-4 shown, a variable focal length surgical microscope objective lens includes a first lens group 10 and a second lens group 40 arranged in sequence along the direction away from the observed object; the first lens group 10 has a negative optical power and includes a first lens 20 and a second lens 30; the first lens 20 is a positive lens, and the first lens 20 has a first concave spherical surface 21 and a first convex spherical surface 22; the first concave spherical surface 21 is concave towards the observed object, and the first convex spherical surface 22 protrudes towards the second lens group 40; the second lens 30 is a negative lens, the second lens group 40 has a 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 between the first lens group 10 and the second lens group 40 is d, 0.8mm < d < 27mm, the focal length of the first lens group 10 is F1, the focal length of the second lens group 40 is F2, and the focal length ratio of the first lens group 10 to the second lens group 40 satisfies the following relational expression: 0.93 < |F1 / F2| < 1.08. When in use, if F1 is -110mm, according to

[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 light beam after passing through the objective lens of the variable-focal-length surgical microscope, passes through a continuously variable-magnification telephoto optical system, and then forms a first magnified image of the observed object by the binocular tube optical system. This image is exactly at the front focal plane of the eyepiece. After the eyepiece magnifies it for a second time, it 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. On the basis of adopting 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 set as a positive lens, and is provided with a first concave spherical surface 21 and a first convex spherical surface 22, so that the first concave spherical surface 21 is concave toward the observed object, and the first convex spherical surface 22 is convex toward the second lens group 40; and the second lens group 40 is set to have positive focal power, adopt a third lens 50 with positive focal power and a positive cementing unit 60 with positive focal power, and at the same time, 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 on the premise of meeting the magnification requirement, thereby expanding its application scope and meeting the use requirements of more departments in the hospital for the working distance of the surgical microscope; and the imaging quality can also 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, 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, so as to improve the excellent imaging quality and lower the manufacturing cost.

[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. On the basis of adopting the above structure and by reasonably arranging the second lens 30, a larger working distance range can be further provided and the cost can be reduced.

[0028] The radius of the second concave spherical surface 31 is the same as the radius 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 points of the third concave spherical surface 32 and 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 excellent imaging quality and lower the manufacturing cost.

[0030] Preferably, -120 mm < F1 < -101 mm. By reasonably setting the focal length of the first lens group 10, a larger working distance range can be further provided.

[0031] The third lens 50 has a second convex spherical surface 51 and a third convex spherical surface 52, and the radius of the second convex spherical surface 51 is greater than the radius of the third convex spherical surface 52. The second convex spherical surface 51 protrudes towards the observed object, and the third convex spherical surface 52 protrudes towards the side of the third lens 50 away from the observed object. By adopting the above structure for the third lens 50, the imaging quality can be improved while being convenient for manufacturing and reducing the cost.

[0032] The focal length of the third lens 50 is F3, and 125 mm < F3 < 170 mm. By reasonably setting the focal length of the third lens 50, a larger working distance range can be further provided.

[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 points of the second convex spherical surface 51 and the third convex spherical surface 52 is 6.63 - 6.77 mm. The diameter of the third lens 50 is 48 mm, so as to improve the excellent imaging quality and lower the manufacturing cost.

[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 relational expression: 3.3 < F4 / F3 < 3.8. By reasonably setting the focal length ratio of the positive cemented unit 60 to the third lens 50, a larger working distance range can be further provided.

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

[0036] The fourth lens 70 has a fourth convex spherical surface 71 and a fifth convex spherical surface 72, and the radius of the fourth convex spherical surface 71 is greater than the radius of the fifth convex spherical surface 72. The fourth convex spherical surface 71 protrudes towards the observed object, and the fifth convex spherical surface 72 protrudes towards the side of the fourth lens 70 away from the observed object. By adopting the above structure for the fourth lens 70, the imaging quality can be improved while being convenient for manufacturing and reducing the cost.

[0037] In this embodiment, the radius of the fourth convex spherical surface 71 is 3031.83mm, 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 63.02mm, 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 7.4-7.6mm, 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 48mm, in order to improve the image 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, and 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 to be observed, and the sixth convex spherical surface 82 is convex toward the side of the fifth lens 80 away from the object to be observed. By adopting the above structure for the fifth lens 80, the imaging quality can be improved, and the manufacturing is convenient and the cost can be reduced.

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

[0040] Specifically, the third lens 50 is located between the first lens group 10 and the positive bonding unit 60, the third convex spherical surface 52 faces the positive bonding unit 60, the fifth convex spherical surface 72 of the fourth lens 70 has the same radius as the fourth concave spherical surface 81, and the fifth convex spherical surface 72 of the fourth lens 70 is bonded to the fourth concave spherical surface 81. The fifth convex spherical surface 72 of the fourth lens 70 is bonded to the fourth concave spherical surface 81 by optical glue, so as to facilitate 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, so as to improve the image quality and lower the manufacturing cost.

[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 the working distance range.

[0043] Preferably, the variable focal length surgical microscope objective lens also includes an adjusting device 90, which includes a mounting seat 91, a screw rod 92, a screw nut 93, and a driving device 94; the first lens group 10 is slidably matched with the mounting seat 91 and connected to the screw nut 93; the screw rod 92 is horizontally arranged and rotatably mounted on the mounting seat 91, and the screw nut 93 is matched and sleeved on the screw rod 92, and the driving device 94 is used to drive the screw rod 92 to rotate. When in use, when the driving device 94 drives the screw rod 92 to rotate in the forward direction, the screw nut 93 can be prompted to move forward to drive the first lens group 10 to move in a direction close to the second lens group 40; when the driving device 94 drives the screw rod 92 to rotate in the reverse direction, the screw nut 93 can be prompted to move backward to drive the first lens group 10 to move in a direction 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 includes a motor, and the output shaft of the motor is connected to the screw rod 92, so as to facilitate the connection.

[0045] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A variable focal length surgical microscope objective lens, characterized in that: It includes a first lens group and a second lens group arranged in sequence along a direction away from the object to be observed; the first lens group has a negative optical power and includes 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 object to be observed, 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 includes 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 focal length ratio of the first lens group to the second lens group satisfies the following relationship: 0.93 < |F1 / F2| < 1.

08.

2. The variable focal length surgical microscope objective lens according to claim 1, characterized in that: The second lens has a second concave spherical surface and a third concave spherical surface, the second concave spherical surface is concave towards the object to be observed, 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, characterized in that: The radius of the second concave spherical surface is the same as that of the first convex spherical surface, and the second concave spherical surface is attached to the first convex spherical surface.

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

5. The variable focal length surgical microscope objective lens according to claim 1, characterized in that: 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 that of the third convex spherical surface.

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

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

8. The variable focal length surgical microscope objective lens according to claim 7, characterized in that: 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.

9. The variable focal length surgical microscope objective lens according to claim 1, characterized in that: The positive cemented unit includes a fourth lens with a positive optical power and a fifth lens with a negative optical power.

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

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