Optical system, surgical microscope and adjustment method

Abstract

The application provides an optical system, a surgical microscope and an adjusting method, and the optical system comprises: an objective lens group; a continuous zoom lens group arranged on an image side of the objective lens group; the objective lens group comprises: a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence on an optical axis from an object side, the first lens and the fifth lens both have negative refractive powers, the second lens, the third lens and the fourth lens all have positive refractive powers, the first lens and the second lens are cemented to form a first cemented lens, the object side surface of the first cemented lens is a concave surface, and the image side surface is a convex surface, the third lens is a double-convex lens, the fourth lens and the fifth lens are cemented to form a second cemented lens, the object side surface of the second cemented lens is a convex surface, and the image side surface is a concave surface; and the objective lens group satisfies the following relationship: through the application, low aberration and high resolution imaging are realized.

Description

Technical Field

[0001] This invention relates to the field of microscope optical systems technology, and more particularly to an optical system, a surgical microscope, and an adjustment method. Background Technology

[0002] Surgical microscopes are the core equipment in modern microsurgery, and their working distance and zoom range are key indicators that determine the freedom and adaptability of surgical operations. A sufficiently long working distance provides surgeons with ample operating space and avoids collisions between surgical instruments and the microscope body; while a wide continuous zoom range enables seamless switching from macroscopic surgical field positioning to microscopic tissue structure observation, meeting the needs of different surgical stages.

[0003] Currently, mainstream technologies in commercial surgical microscopes, such as those from brands like Zeiss and Leica, generally limit their working distance to 200-600mm and their zoom range to 190-500mm. Existing technologies, constrained by the physical limitations of their optical structures, struggle to significantly expand both working distance and zoom range while maintaining high image quality. For example, Chinese utility model patent application number 202020174155.8 discloses a zoom objective system composed of three sets of cemented doublet lenses, but its explicitly stated continuous zoom range is only 200-450mm. A short proximal working distance (e.g., 200mm) easily interferes with the surgeon's instrument manipulation, limiting its application in confined spaces or surgeries requiring high degrees of freedom. Furthermore, the limited zoom range restricts the microscope's adaptability to different depth-of-field and magnification requirements.

[0004] Due to limitations in working distance and zoom range, during surgery, when the distance between the target area and the objective lens changes, the surgeon or assistant needs to frequently adjust the focus and working distance, either manually or electrically. This frequent intervention not only disrupts the flow of the surgery and reduces efficiency, but may also introduce potential risks due to improper or delayed adjustments.

[0005] Existing technologies, in pursuing large working distances or large zoom ratios, often struggle to simultaneously achieve high resolution, low aberrations, and stereoscopic imaging quality across the entire field of view. This can lead to issues such as blurred or distorted image edges, or reduced brightness, at extreme working distances or magnifications, affecting the doctor's accurate judgment.

[0006] Therefore, existing surgical microscopes face insurmountable technical obstacles in achieving a combination of ultra-large working distance, ultra-large zoom range, and high imaging quality.

[0007] It should be noted that the above description of the background technology is only for the purpose of providing a clear and complete explanation of the technical solutions of the present invention and facilitating understanding by those skilled in the art. It should not be assumed that the above technical solutions are known to those skilled in the art simply because they have been described in the background section of the present invention. Summary of the Invention

[0008] The purpose of this invention is to solve the problem that existing surgical microscopes cannot simultaneously achieve ultra-large working distance, ultra-large zoom range, and high imaging quality.

[0009] To achieve the above objectives, the present invention provides an optical system comprising:

[0010] The objective lens assembly is used to receive light rays from the object surface and form parallel light rays for emission.

[0011] A continuous zoom lens group is positioned on the image side of the objective lens group to receive the parallel light and perform zoom imaging;

[0012] The objective lens assembly includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the object side. The first lens and the fifth lens both have negative optical power, while the second lens, the third lens, and the fourth lens all have positive optical power. The first lens and the second lens are cemented together to form a first cemented lens, wherein the object-side surface of the first cemented lens is concave and the image-side surface is convex. The third lens is a biconvex lens. The fourth lens and the fifth lens are cemented together to form a second cemented lens, wherein the object-side surface of the second cemented lens is convex and the image-side surface is concave.

[0013] The objective lens group satisfies the following relationship:

[0014]

[0015]

[0016] Wherein, F refers to the focal length of the objective lens group, and f 12 This refers to the focal length of the first cemented lens, f. 345 It refers to the combined focal length of the third lens and the second cemented lens, M refers to the distance between the image-side surface of the second lens and the object-side surface of the third lens, WD refers to the working distance of the optical system, and v2 refers to the image distance between the third lens and the second cemented lens.

[0017] As a further improvement of the present invention, the continuous zoom lens group includes: a third cemented lens with positive optical power, a fourth cemented lens with negative optical power, an aperture stop, a fifth cemented lens with negative optical power, and a sixth cemented lens with positive optical power, arranged sequentially along the optical axis from the object side. The object-side surface of the third cemented lens is convex and the image-side surface is concave; the object-side surface of the fourth cemented lens is concave and the image-side surface is convex; the object-side surface of the fifth cemented lens is concave and the image-side surface is convex; and the object-side surface of the sixth cemented lens is convex and the image-side surface is concave.

[0018] As a further improvement of the present invention

[0019] The third cemented lens includes: a sixth lens with positive optical power and a seventh lens with negative optical power arranged sequentially along the optical axis from the object side, wherein the object-side surface of the sixth lens is convex and the image-side surface is concave, and both the object-side surface and the image-side surface of the seventh lens are convex.

[0020] The fourth cemented lens includes: an eighth lens with negative optical power and a ninth lens with positive optical power arranged sequentially along the optical axis from the object side. The object-side surface of the eighth lens is concave and the image-side surface is convex. The object-side surface and the image-side surface of the ninth lens are both concave.

[0021] The fifth cemented lens includes: a tenth lens with positive optical power and an eleventh lens with negative optical power arranged sequentially along the optical axis from the object side. The object-side surface and the image-side surface of the tenth lens are both concave, and the object-side surface of the eleventh lens is convex and the image-side surface is concave.

[0022] The sixth cemented lens includes a twelfth lens with positive optical power and a thirteenth lens with positive optical power arranged sequentially along the optical axis from the object side. The object-side surface and the image-side surface of the twelfth lens are both convex, and the object-side surface of the thirteenth lens is concave and the image-side surface is convex.

[0023] As a further improvement of the present invention, the optical system includes a continuous zoom lens group, the optical axis of which is offset from the optical axis of the objective lens group.

[0024] As a further improvement of the present invention, the optical system includes two continuously zoom lens groups, and the two optical axes of the two continuously zoom lens groups are symmetrically arranged from the optical axis of the objective lens group.

[0025] As a further improvement of the present invention

[0026] The Abbe number V1 of the first lens and the Abbe number V2 of the second lens satisfy 28 < |V1-V2| < 33;

[0027] The Abbe number V3 of the third lens satisfies 70 < V3;

[0028] The Abbe number V4 of the fourth lens and the Abbe number V5 of the fifth lens satisfy 28 < |V4 - V5| < 29.

[0029] As a further improvement of the present invention

[0030] The refractive index n1 of the first lens satisfies 1.7 < n1 < 1.9;

[0031] The refractive index n1 of the first lens and the refractive index n2 of the second lens satisfy 0.15 < |n1-n2| < 0.25;

[0032] The refractive index n3 of the third lens satisfies 1.5 < n3;

[0033] The refractive index n4 of the fourth lens satisfies 1.85 < n4;

[0034] The refractive index n4 of the fourth lens and the refractive index n5 of the fifth lens satisfy 0.28 < |n4 - n5| < 0.3.

[0035] As a further improvement of the present invention, the diameter of the objective lens group is larger than the diameter of any lens in the continuous zoom lens group.

[0036] Based on the same inventive concept, the present invention also discloses a surgical microscope, comprising: an optical system as described in any of the foregoing inventions.

[0037] Based on the same inventive concept, this invention also discloses an adjustment method for adjusting an optical system as described in any of the foregoing inventions, the adjustment method comprising:

[0038] The focal length of the objective lens system is adjusted by changing the distance between the image-side surface of the second lens and the object-side surface of the third lens, thereby adapting to different working distance requirements of the optical system.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] In this invention, the optical system includes an objective lens group and a continuous zoom lens group. The objective lens group receives light from the object surface and forms parallel light rays for emission; the continuous zoom lens group is disposed on the image side of the objective lens group and is used to receive parallel light and perform zoom imaging. The objective lens group includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the object side. The first lens and the fifth lens both have negative optical power, while the second lens, the third lens, and the fourth lens all have positive optical power. The first lens and the second lens are cemented together to form a first cemented lens, the object-side surface of which is concave and the image-side surface of which is convex. The third lens is a biconvex lens. The fourth lens and the fifth lens are cemented together to form a second cemented lens, the object-side surface of which is convex and the image-side surface of which is concave. The design employs a large-range zoom and variable working distance objective lens group, consisting of five traditional glass lenses from the first to the fifth lens. By adjusting the distance between the image-side surface of the second lens and the object-side surface of the third lens, a large working distance of 301-1000mm is achieved. That is, it can achieve a large working distance of 301-1000mm and a zoom range of 415-1024.2205mm to adapt to some special surgical scenarios. At the same time, in conjunction with the continuous zoom lens group, low aberration and high-resolution imaging can be achieved throughout the entire focal length range and the entire working distance range. Attached Figure Description

[0041] Figure 1 This is the cross-sectional structure of the objective lens assembly shown in this invention;

[0042] Figure 2 This is the cross-sectional structure of the continuous zoom lens assembly shown in this invention;

[0043] Figure 3 This is a cross-sectional structure of an optical system in one embodiment;

[0044] Figure 4 This is a cross-sectional structure of the optical system in another embodiment;

[0045] Figure 5 The cross-sectional structure of the optical system shown in Example 1;

[0046] Figure 6 The cross-sectional structure of the optical system shown in Example 2;

[0047] Figure 7 The cross-sectional structure of the optical system shown in Example 3;

[0048] Figure 8 The cross-sectional structure of the optical system shown in Example 4;

[0049] Figure 9 The cross-sectional structure of the optical system shown in Example 5;

[0050] Figure 10 The MTF curve of the optical system shown in Example 1 is plotted in the central field of view;

[0051] Figure 11 The MTF curve of the optical system shown in Example 1 at a field of view of 1.0 degrees is shown.

[0052] Figure 12 The MTF curve of the optical system shown in Example 1 at a field of view of 2.2 degrees is shown below.

[0053] Figure 13 The MTF curve of the optical system shown in Example 2 is shown in the central field of view.

[0054] Figure 14 The MTF curve of the optical system shown in Example 2 at a field of view of 1.0 degrees is shown below.

[0055] Figure 15 The MTF curve of the optical system shown in Example 2 at a field of view of 2.2 degrees is shown below.

[0056] Figure 16 The MTF curve of the optical system shown in Example 3 is shown in the central field of view.

[0057] Figure 17 The MTF curve of the optical system shown in Example 3 at a field of view of 1.0 degrees is shown.

[0058] Figure 18 The MTF curve of the optical system shown in Example 3 at a field of view of 2.2 degrees is shown.

[0059] Figure 19 The MTF curve of the optical system shown in Example 4 is shown in the central field of view.

[0060] Figure 20 The MTF curve of the optical system shown in Example 4 at a field of view of 1.0 degrees is shown below.

[0061] Figure 21 The MTF curve of the optical system shown in Example 4 at a field of view of 2.2 degrees is shown below.

[0062] Figure 22 The MTF curve of the optical system shown in Example 5 is shown in the central field of view.

[0063] Figure 23 The MTF curve of the optical system shown in Example 5 at a field of view of 1.0 degrees is shown.

[0064] Figure 24MTF curve graph of the optical system shown in Embodiment 5 at a field angle of 2.2 degrees;

[0065] Figure 25 Seidel diagram of the optical system shown in Embodiment 1;

[0066] Figure 26 Seidel diagram of the optical system shown in Embodiment 2;

[0067] Figure 27 Seidel diagram of the optical system shown in Embodiment 3;

[0068] Figure 28 Seidel diagram of the optical system shown in Embodiment 4;

[0069] Figure 29 Seidel diagram of the optical system shown in Embodiment 5;

[0070] Figure 30 Simulation imaging diagram of the optical system shown in Embodiment 1;

[0071] Figure 31 Simulation imaging diagram of the optical system shown in Embodiment 2;

[0072] Figure 32 Simulation imaging diagram of the optical system shown in Embodiment 3;

[0073] Figure 33 Simulation imaging diagram of the optical system shown in Embodiment 4;

[0074] Figure 34 Simulation imaging diagram of the optical system shown in Embodiment 5;

[0075] Figure 35 Curve graph of the variation relationship among WD, M, and F. Detailed implementation manners

[0076] The present invention will be described in detail below in conjunction with the various implementation manners shown in the accompanying drawings. However, it should be noted that these implementation manners are not limitations on the present invention, and any equivalent transformation or substitution in terms of function, method, or structure made by those of ordinary skill in the art based on these implementation manners shall fall within the protection scope of the present invention.

[0077] It should be noted that in the present invention, the "object side" refers to the side of the optical system 100 close to the object plane, that is, the side where light enters the optical system 100; the "image side" refers to the side of the optical system 100 close to the image plane, that is, the side where light exits the optical system 100.

[0078] Refer Figures 1 to 25As shown, this invention illustrates a specific embodiment of an optical system 100. The optical system 100 is installed in a surgical microscope (not shown) used for observing an object (e.g., living or ex vivo biological tissue). Specifically, it is configured at the observation end of the surgical microscope to capture optical information of the observed object during surgery and transmit this optical information to subsequent imaging components (e.g., an image processing and display system, not shown in this invention), thereby providing the surgeon with a clear surgical field image.

[0079] Specifically, participants Figures 1 to 4 As shown, the optical system 100 includes an objective lens group 10 and a continuous zoom lens group 20. The objective lens group 10 is used to receive light from the object surface and form parallel light rays for emission; the continuous zoom lens group 20 is disposed on the image side of the objective lens group 10 and is used to receive parallel light rays and perform zoom imaging. The objective lens group 10 includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, and a fifth lens 15 arranged sequentially along the optical axis (i.e., optical axis 31) from the object side. The first lens 11 and the fifth lens 15 both have negative optical power, and the second lens 12, the third lens 13, and the fourth lens 14 all have positive optical power. The first lens 11 and the second lens 12 are cemented together to form a first cemented lens 101, the object-side surface S1 of the first cemented lens 101 being concave and the image-side surface S3 being convex. The third lens 13 is a biconvex lens, that is, both the object-side surface S4 and the image-side surface S5 of the third lens 13 are convex. The fourth lens 14 and the fifth lens 15 are cemented together to form a second cemented mirror 102. The object-side surface S6 of the second cemented mirror 102 is convex, and the image-side surface S8 is concave.

[0080] In this invention, the objective lens assembly 100 satisfies the following relationship:

[0081]

[0082] F refers to the focal length of objective lens group 10. 12 This refers to the focal length of the first cemented lens 101, f. 345 The focal length of the third lens 13 and the cemented lens 102 is defined as follows: M refers to the distance between the image-side surface S3 of the second lens 12 and the object-side surface S4 of the third lens 13; WD refers to the working distance of the optical system 100; and v2 refers to the image distance between the third lens 13 and the cemented lens 102. Thus, a relationship is established between the distance M between the image-side surface S3 of the second lens 12 and the object-side surface S4 of the third lens 13 (which can also be understood as the zoom interval), the focal length F of the objective lens group 10, and the working distance WD of the optical system 100, to achieve a large working distance variation.

[0083] Based on this, the present invention also discloses an adjustment method for adjusting the aforementioned optical system 100. Specifically, the adjustment method includes: adjusting the distance M between the image-side surface S3 of the second lens 12 and the object-side surface S4 of the third lens 13 to adjust the focal length F of the objective lens group 10, thereby using different working distance requirements of the optical system 100.

[0084] It should be noted that the optical system 100 disclosed in this invention adopts a design scheme of a large-range zoom and variable working distance objective lens group, which consists of five conventional glass lenses from the first lens 11 to the fifth lens 15. By adjusting the distance M between the image-side surface S3 of the second lens 12 and the object-side surface S4 of the third lens 13, a large working distance of 301-1000mm is achieved. That is, a zoom range of 415-1024.2205mm can be achieved to adapt to some special surgical scenarios. At the same time, in conjunction with the continuous zoom lens group 20, low aberration and high resolution imaging can be achieved throughout the entire focal length range and the entire working distance range. In summary, the focal length F of the objective lens group 10 in this invention satisfies 415mm≤F≤1024.2205mm, the distance M between the image-side surface S3 of the second lens 12 and the object-side surface S4 of the third lens 13 satisfies 0.5141mm≤M≤39.2874mm, and the working distance WD of the optical system 100 satisfies 301mm≤WD≤1000mm.

[0085] Furthermore, the image-side surface S2 of the first lens 11 is convex, and the object-side surface S2 of the second lens 12 is concave. The first lens 11 and its image-side surface S2, as well as the object-side surface S2 of the second lens 12, are bonded together to form a first bonding surface S2. The image-side surface S7 of the fourth lens 14 is concave, and the object-side surface S7 of the fifth lens 15 is convex. The image-side surface S7 of the fourth lens 14 and the object-side surface S7 of the fifth lens 15 are bonded together to form a second bonding surface S7.

[0086] In one embodiment, the Abbe number V1 of the first lens 11 and the Abbe number V2 of the second lens 12 satisfy 28 < |V1-V2| < 33; the Abbe number V3 of the third lens 13 satisfies 70 < V3; and the Abbe number V4 of the fourth lens 14 and the Abbe number V5 of the fifth lens 15 satisfy 28 < |V4-V5| < 29.

[0087] It should be noted that the first lens 11 and the second lens 12 employ a combination of low-dispersion and high-dispersion materials to correct spherical aberration and coma. A larger difference in Abbe number indicates a greater difference in the dispersive capabilities of the two materials. Chromatic aberration correction can be achieved with a smaller optical power (i.e., a "flatter" lens curvature), which helps to simultaneously control other monochromatic aberrations (such as spherical aberration and coma). The third lens 13 uses an ultra-low-dispersion material, i.e., 70 < V3, to further correct the second-order spectrum. The fourth lens 14 and the fifth lens 15 also employ a combination of low-dispersion and high-dispersion materials to compensate for the on-axis and transverse chromatic aberration generated by the first lens 11 and the second lens 12.

[0088] In one embodiment, the refractive index n1 of the first lens 11 satisfies 1.7 < n1 < 1.9; the refractive index n1 of the first lens 11 and the refractive index n2 of the second lens 12 satisfy 0.15 < |n1-n2| < 0.25; the refractive index n3 of the third lens 13 satisfies 1.5 < n3; the refractive index n4 of the fourth lens 14 satisfies 1.85 < n4; and the refractive index n4 of the fourth lens 14 and the refractive index n5 of the fifth lens 15 satisfy 0.28 < |n4-n5| < 0.3.

[0089] It should be noted that the first lens 11 is made of a high refractive index material, which can provide strong refractive power and control spherical aberration. The refractive index constraint of the second lens 12 is set to achieve the correction of monochromatic aberration. The refractive index constraint of the third lens 13 can achieve the correction of second-order spectral chromatic aberration. The combined refractive index constraint of the fourth lens 14 and the fifth lens 15 can achieve the correction of field curvature and astigmatism.

[0090] In one implementation, the reference Figures 2 to 4 As shown, the continuous zoom lens group 20 includes: a third cemented lens 201 with positive optical power, a fourth cemented lens 202 with negative optical power, an aperture stop 25, a fifth cemented lens 203 with negative optical power, and a sixth cemented lens 204 with positive optical power, arranged sequentially along the optical axis (i.e., optical axis 32) from the object side. The object-side surface S9 of the third cemented lens 201 is convex and the image-side surface S11 is concave; the object-side surface S12 of the fourth cemented lens 202 is concave and the image-side surface S14 is convex; the object-side surface S16 of the fifth cemented lens 203 is concave and the image-side surface S18 is convex; and the object-side surface S19 of the sixth cemented lens 204 is convex and the image-side surface S21 is concave.

[0091] Furthermore, participants Figure 2As shown, the third cemented lens 201 includes a sixth lens 21 with positive optical power and a seventh lens 22 with negative optical power, arranged sequentially along the optical axis (i.e., optical axis 32) from the object side. The object-side surface S9 of the sixth lens 21 is convex, and the image-side surface S10 is concave. The object-side surface S10 and the image-side surface S11 of the seventh lens 22 are both convex, and the image-side surface S10 of the sixth lens 21 and the object-side surface S10 of the seventh lens 22 are cemented together to form a third cemented surface S10. The fourth cemented lens 202 includes an eighth lens 23 with negative optical power and a ninth lens 24 with positive optical power, arranged sequentially along the optical axis (i.e., optical axis 32) from the object side. The object-side surface S12 of the eighth lens 23 is concave, and the image-side surface S13 is convex. Both the object-side surface S13 and the image-side surface S14 of the ninth lens 24 are concave. The image-side surface S13 of the eighth lens 23 and the object-side surface S13 of the ninth lens 24 are cemented together to form a fourth cemented surface S13. The fifth cemented lens 203 includes a tenth lens 26 with positive optical power and an eleventh lens 27 with negative optical power, arranged sequentially along the optical axis (i.e., optical axis 32) from the object side. Both the object-side surface S16 and the image-side surface S17 of the tenth lens 26 are concave. The object-side surface S17 of the eleventh lens 27 is convex, and the image-side surface S18 is concave. The image-side surface S17 of the tenth lens 26 and the object-side surface S17 of the eleventh lens 27 are cemented together to form a fifth cemented surface S17. The sixth cemented lens 204 includes a twelfth lens 28 and a thirteenth lens 29, both having positive optical power, arranged sequentially along the optical axis (i.e., optical axis 32) from the object side. The object-side surface S19 and the image-side surface S20 of the twelfth lens 28 are both convex, while the object-side surface S20 of the thirteenth lens 29 is concave and the image-side surface S21 is convex. The image-side surface S20 of the twelfth lens 28 and the object-side surface S20 of the thirteenth lens 29 are cemented together to form the sixth cemented surface S20.

[0092] Specific embodiments of the objective lens group 10 and the continuous zoom lens group 20 included in the optical system 100. In one embodiment, see... Figure 3 As shown, the optical system 100' includes only one continuous zoom lens group 20', whose optical axis 32' and the optical axis 31 of the objective lens group 10 are offset to ultimately form a two-dimensional planar image. In another embodiment, refer to Figure 4 As shown, the optical system 100” includes two continuous zoom lens groups 20 (i.e., continuous zoom lens group 20” and continuous zoom lens group 20”'), and the optical axes 32 of the two continuous zoom lens groups 20 (i.e., optical axis 32” and optical axis 32”') are symmetrically arranged from the optical axis 31 of the objective lens group 10.

[0093] In one embodiment, the diameter of the objective lens group 10 is larger than the diameter of any one lens in the continuous zoom lens group 20, so as to be applied to binocular vision imaging. The diameter of the objective lens group 10 is larger than the sum of the binocular lenses and the interpupillary distance, and the large aperture of the objective lens group 10 is beneficial to obtaining a large amount of incident light, with good light collection performance, and can improve the theoretical limit resolution.

[0094] The following describes the numerical examples of the optical system 100 of the present invention.

[0095] [Example 1]

[0096] As shown Figure 5 The optical system 100a is sequentially arranged from the object side through the objective lens group 10a (including the first lens 11 with negative focal power, the second lens 12 with positive focal power, the third lens 13 with positive focal power, the fourth lens 14 with positive focal power, and the fifth lens 15 with negative focal power) and the continuous zoom lens group 20a (including the sixth lens 21 with positive focal power, the seventh lens 22 with negative focal power, the eighth lens 23 with negative focal power, the ninth lens 24 with positive focal power, the tenth lens 26 with positive focal power, the eleventh lens 27 with negative focal power, the twelfth lens 28 with positive focal power, and the thirteenth lens 29 with positive focal power). The optical axis 31 of the objective lens group 10a and the optical axis 32 of the continuous zoom lens group 20a are arranged offset.

[0097] Table 1 shows the basic parameter table of the surfaces included in the optical system 100a of Example 1, including the object surface S0, the surface S15 of the aperture 25, the idealized virtual surface S22, and the image surface S23, which includes the surface serial number, surface type, radius of curvature, thickness, refractive index number, and diameter. The ideal virtual surface S22 refers to an idealized virtual surface.

[0098] In the column of surface serial number in the basic parameter table, S0 corresponds to the object surface, S1 - S14 correspond to the surfaces of the first lens 11 to the ninth lens 24 from the side closest to the object to the side closest to the image in sequence, S15 corresponds to the surface of the aperture 25, S16 - S21 correspond to the surfaces of the tenth lens 26 to the thirteenth lens 29 from the side closest to the object to the side closest to the image in sequence, S22 corresponds to the idealized virtual surface, and S23 corresponds to the image surface.

[0099] The column of surface type indicates the surface type corresponding to the surface of the current surface serial number, including the standard surface and the paraxial surface.

[0100] The column of radius of curvature indicates the radius of curvature corresponding to the surface of the current surface serial number (unit: millimeter, mm), and the sign of the radius of curvature is positive when the surface forms a convex shape towards the object side and negative when it forms a convex shape towards the image side.

[0101] The thickness column indicates the distance (in millimeters, mm) between the current face number and the next face number, specifically the distance between the vertices of the two faces (i.e., the intersection of the face and the principal optical axis).

[0102] The refractive index column indicates the refractive index of each lens, and it should be filled in at the corresponding surface number of the object-side surface of that lens.

[0103] The Abbe number column represents the dispersion coefficient of each lens material, and it is filled in at the corresponding surface number of the object surface of the lens.

[0104] The diameter column indicates the diameter (unit: millimeters, mm) of the face with the current face number.

[0105] The working distance of the optical system 100a shown in Example 1 is 301 mm. "Millimeter" (abbreviated "mm") is used as the unit of length for the values ​​in Table 1, but it is only one column and can be used by scaling up or down proportionally; therefore, other appropriate units may also be used. Table 1 also shows values ​​rounded to a specified number of decimal places.

[0106]

[0107]

[0108] As shown in Table 1, the thickness interval of surface number S3 can be adjusted according to the working distance, with an adjustment range of 0.4939mm-39.287mm. The thickness intervals of surface numbers S11, S14, and S18 can be adjusted according to the zoom requirements. Among them, the total optical length of the continuous zoom lens group 20a is 67.023mm.

[0109] Figures 10 to 12 The MTF curves of Example 1 are shown at the center field of view, at a field of view angle of 1.0 degrees, and at a field of view angle of 2.2 degrees. Figures 10 to 12 The ideal MTF curve is also shown for comparison. Figures 10 to 12 In the diagram, the solid black line and the dashed black line represent the MTF curves of optical system 100a under ideal conditions in the meridional and sagittal directions, respectively. Furthermore, under ideal conditions, the MTF curves in the meridional and sagittal directions coincide. Therefore... Figures 10 to 12 The black solid lines and black dashed lines contained herein overlap, and only the black solid lines are shown. The blue solid lines and blue dashed lines represent the MTF curves of optical system 100a in the meridional and sagittal directions at the central field of view, respectively. The green solid lines and green dashed lines represent the MTF curves of optical system 100a in the meridional and sagittal directions at a 1.0-degree field of view, respectively. The red solid lines and red dashed lines represent the MTF curves of optical system 100a in the meridional and sagittal directions at a 2.2-degree field of view, respectively.

[0110] Specifically, with a working distance of 301 mm, the average value of the MTF0.5 in the meridional direction of the optical system 100a under multiple fields of view reached 38.73 lp / mm, the average value of the MTF0.2 in the meridional direction under multiple fields of view reached 67 lp / mm, the average value of the MTF0.5 in the sagittal direction under multiple fields of view approached the diffraction limit, that is, reached 60 lp / mm, and the average value of the MTF0.2 in the sagittal direction under multiple fields of view approached the diffraction limit, that is, reached 104 lp / mm.

[0111] Unless otherwise specified, the above-described methods of illustrating the optical system 100a of Embodiment 1, the symbols, meanings, and methods of recording various data are also applicable to the optical systems 100b-100e of Embodiments 2-5.

[0112] [Example 2]

[0113] like Figure 6 As shown, the optical system 100b is formed by the objective lens group 10b (comprising a first lens 11 with negative optical power, a second lens 12 with positive optical power, a third lens 13 with positive optical power, a fourth lens 14 with positive optical power, and a fifth lens 15 with negative optical power) and the continuous zoom lens group 20a (comprising a sixth lens 21 with positive optical power, a seventh lens 22 with negative optical power, an eighth lens 23 with negative optical power, a ninth lens 24 with positive optical power, a tenth lens 26 with positive optical power, an eleventh lens 27 with negative optical power, a twelfth lens 28 with positive optical power, and a thirteenth lens 29 with positive optical power) arranged sequentially from the object side. The optical axis 31 of the objective lens group 10b and the optical axis 32 of the continuous zoom lens group 20a are offset.

[0114] The difference between optical system 100b and optical system 100a is that the working distance of optical system 100a is 301mm, while the working distance of optical system 100b is 400mm, and the distance M between the image-side surface S3 of the second lens 12 and the object-side surface S4 of the third lens 13 is different. All other parameters are the same, and the parameter table will not be shown here. For details, please refer to the previous description.

[0115] Figures 13 to 15 The MTF curves of Example 2 are shown at the center field of view, at a field of view angle of 1.0 degrees, and at a field of view angle of 2.2 degrees. Figures 13 to 15 The ideal MTF curve is also shown for comparison. Figures 13 to 15 In the diagram, the solid black line and the dashed black line represent the MTF curves of optical system 100b under ideal conditions in the meridional and sagittal directions, respectively. Furthermore, under ideal conditions, the MTF curves in the meridional and sagittal directions coincide. Figures 13 to 15The black solid lines and black dashed lines contained herein overlap, and only the black solid lines are shown. The blue solid lines and blue dashed lines represent the MTF curves of the optical system 100b in the meridional and sagittal directions at the central field of view, respectively. The green solid lines and green dashed lines represent the MTF curves of the optical system 100b in the meridional and sagittal directions at a 1.0-degree field of view, respectively. The red solid lines and red dashed lines represent the MTF curves of the optical system 100b in the meridional and sagittal directions at a 2.2-degree field of view, respectively.

[0116] Specifically, with a working distance of 400 mm, the average value of the 100b optical system's meridional MTF0.5 in multiple fields of view reached 44 lp / mm, the average value of the meridional MTF0.2 in multiple fields of view reached 79 lp / mm, the average value of the sagittal MTF0.5 in multiple fields of view approached the diffraction limit, reaching 61 lp / mm, and the average value of the sagittal MTF0.2 in multiple fields of view approached the diffraction limit, reaching 104 lp / mm.

[0117] [Example 3]

[0118] like Figure 7 As shown, the optical system 100c is formed by the objective lens group 10c (including a first lens 11 with negative optical power, a second lens 12 with positive optical power, a third lens 13 with positive optical power, a fourth lens 14 with positive optical power, and a fifth lens 15 with negative optical power) and the continuous zoom lens group 20a (including a sixth lens 21 with positive optical power, a seventh lens 22 with negative optical power, an eighth lens 23 with negative optical power, a ninth lens 24 with positive optical power, a tenth lens 26 with positive optical power, an eleventh lens 27 with negative optical power, a twelfth lens 28 with positive optical power, and a thirteenth lens 29 with positive optical power) arranged sequentially from the object side. The optical axis 31 of the objective lens group 10c and the optical axis 32 of the continuous zoom lens group 20a are offset.

[0119] The difference between optical system 100c and optical system 100a is that the working distance of optical system 100a is 301mm, while the working distance of optical system 100c is 600mm, and the distance M between the image-side surface S3 of the second lens 12 and the object-side surface S4 of the third lens 13 is different. All other parameters are the same, and the parameter table will not be shown here. For details, please refer to the previous description.

[0120] Figures 16 to 18 The MTF curves of Example 3 are shown at the center field of view, at a field of view angle of 1.0 degrees, and at a field of view angle of 2.2 degrees. Figures 16 to 18 The ideal MTF curve is also shown for comparison. Figures 16 to 18In the diagram, the solid black line and the dashed black line represent the MTF curves of the optical system 100c under ideal conditions in the meridional and sagittal directions, respectively. Furthermore, under ideal conditions, the MTF curves in the meridional and sagittal directions coincide. Therefore... Figures 16 to 18 The black solid lines and black dashed lines contained herein overlap, and only the black solid lines are shown. The blue solid lines and blue dashed lines represent the MTF curves of the optical system 100c in the meridional and sagittal directions at the central field of view, respectively. The green solid lines and green dashed lines represent the MTF curves of the optical system 100c in the meridional and sagittal directions at a 1.0-degree field of view, respectively. The red solid lines and red dashed lines represent the MTF curves of the optical system 100c in the meridional and sagittal directions at a 2.2-degree field of view, respectively.

[0121] Specifically, with a working distance of 600 mm, the average value of the optical system's MTF0.5 in the meridional direction under multiple fields of view reached 52 lp / mm, the average value of the MTF0.2 in the meridional direction under multiple fields of view reached 93 lp / mm, the average value of the MTF0.5 in the sagittal direction under multiple fields of view approached the diffraction limit, reaching 60 lp / mm, and the average value of the MTF0.2 in the sagittal direction under multiple fields of view approached the diffraction limit, reaching 105 lp / mm.

[0122] [Example 4]

[0123] like Figure 8 As shown, the optical system 100d is formed by the objective lens group 10d (comprising a first lens 11 with negative optical power, a second lens 12 with positive optical power, a third lens 13 with positive optical power, a fourth lens 14 with positive optical power, and a fifth lens 15 with negative optical power) and the continuous zoom lens group 20a (comprising a sixth lens 21 with positive optical power, a seventh lens 22 with negative optical power, an eighth lens 23 with negative optical power, a ninth lens 24 with positive optical power, a tenth lens 26 with positive optical power, an eleventh lens 27 with negative optical power, a twelfth lens 28 with positive optical power, and a thirteenth lens 29 with positive optical power) arranged sequentially from the object side. The optical axis 31 of the objective lens group 10d and the optical axis 32 of the continuous zoom lens group 20a are offset.

[0124] The difference between optical system 100d and optical system 100a is that the working distance of optical system 100a is 301mm, while the working distance of optical system 100d is 800mm, and the distance M between the image-side surface S3 of the second lens 12 and the object-side surface S4 of the third lens 13 is different. All other parameters are the same, and the parameter table will not be shown here. For details, please refer to the previous description.

[0125] Figures 19 to 21The MTF curves of Example 4 are shown at the center field of view, at a field of view angle of 1.0 degrees, and at a field of view angle of 2.2 degrees. Figures 19 to 21 The ideal MTF curve is also shown for comparison. Figures 19 to 21 In the diagram, the solid black line and the dashed black line represent the MTF curves of the optical system 100d under ideal conditions in the meridional and sagittal directions, respectively. Furthermore, under ideal conditions, the MTF curves in the meridional and sagittal directions coincide. Figures 19 to 21 The black solid lines and black dashed lines contained herein overlap, and only the black solid lines are shown. The blue solid lines and blue dashed lines represent the MTF curves of the optical system 100d in the meridional and sagittal directions at the central field of view, respectively. The green solid lines and green dashed lines represent the MTF curves of the optical system 100d in the meridional and sagittal directions at a 1.0-degree field of view, respectively. The red solid lines and red dashed lines represent the MTF curves of the optical system 100d in the meridional and sagittal directions at a 2.2-degree field of view, respectively.

[0126] Specifically, at a working distance of 800 mm, the average value of the optical system's MTF0.5 in the 100d meridional direction under multiple fields of view is close to the diffraction limit, reaching 55 lp / mm; the average value of the MTF0.2 in the meridional direction under multiple fields of view is close to the diffraction limit, reaching 98 lp / mm; the average value of the MTF0.5 in the sagittal direction under multiple fields of view is close to the diffraction limit, reaching 61 lp / mm; and the average value of the MTF0.2 in the sagittal direction under multiple fields of view is close to the diffraction limit, reaching 105 lp / mm.

[0127] [Example 5]

[0128] like Figure 9 As shown, the optical system 100e is formed by the objective lens group 10e (comprising a first lens 11 with negative optical power, a second lens 12 with positive optical power, a third lens 13 with positive optical power, a fourth lens 14 with positive optical power, and a fifth lens 15 with negative optical power) and the continuous zoom lens group 20a (comprising a sixth lens 21 with positive optical power, a seventh lens 22 with negative optical power, an eighth lens 23 with negative optical power, a ninth lens 24 with positive optical power, a tenth lens 26 with positive optical power, an eleventh lens 27 with negative optical power, a twelfth lens 28 with positive optical power, and a thirteenth lens 29 with positive optical power) arranged sequentially from the object side. The optical axis 31 of the objective lens group 10e and the optical axis 32 of the continuous zoom lens group 20a are offset.

[0129] The difference between the optical system 100e and the optical system 100a lies in that: the working distance of the optical system 100a is 301 mm, while the working distance of the optical system 100e is 1000 mm and the distance M between the image-side surface S3 of the second lens 12 and the object-side surface S4 of the third lens 13 is different, and other parameters are the same. The parameter table is not shown here, and specific details can be referred to the previous description.

[0130] Figures 22 to 24 The MTF curves of Example 5 at the central field of view, at a field angle of 1.0 degree, and at a field angle of 2.2 degrees are respectively shown, and Figures 22 to 24 the MTF curve under ideal conditions is also shown in the figure for comparison. In Figures 22 to 24 the figure, the solid black line and the dashed black line respectively refer to the MTF curves of the optical system 100e in the meridional direction and the sagittal direction under ideal conditions, and the MTF curves in the meridional direction and the sagittal direction coincide under ideal conditions. Therefore Figures 22 to 24 the solid black line and the dashed black line included in the figure coincide, and only the solid black line can be shown. The solid blue line and the dashed blue line respectively refer to the MTF curves of the optical system 100e in the meridional direction and the sagittal direction at the central field of view. The solid green line and the dashed green line respectively refer to the MTF curves of the optical system 100e in the meridional direction and the sagittal direction at a field angle of 1.0 degree. The solid red line and the dashed red line respectively refer to the MTF curves of the optical system 100e in the meridional direction and the sagittal direction at a field angle of 2.2 degrees.

[0131] Specifically, when the working distance is 1000 mm, the average value of MTF0.5 in the meridional direction of the optical system 100e at multiple fields of view is close to the diffraction limit, reaching 57 lp / mm. The average value of MTF0.2 in the meridional direction at multiple fields of view is close to the diffraction limit, reaching 100 lp / mm. The average value of MTF0.5 in the sagittal direction at multiple fields of view approaches the diffraction limit, that is, it reaches 61 lp / mm. The average value of MTF0.2 in the sagittal direction at multiple fields of view approaches the diffraction limit, that is, it reaches 105 lp / mm.

[0132] In summary, it can be seen that in the above Examples 1-5, by adjusting the working distance WD, the distance M between the image-side surface S3 of the second lens 12 and the object-side surface S4 of the third lens 13 and the focal length F of the objective lens group 10 are further adjusted. Refer Figure 35 to the figure shown, the present invention shows the curve graph of the change relationship among WD, M, and F. At the same time, the specific adjustment values among WD, M, and F are shown in Table 2 below.

[0133] 39.2874 415.0394 301 28.0724 501.2771 400 20.0789 588.4209 500 14.1465 675.5821 600 9.5697 762.7490 700 5.9318 849.9141 800 2.9708 937.0725 900 0.5141 1024.2205 1000

[0134] Table 2

[0135] Refer Figures 10 to 24As shown, in an ideal situation, the coincidence of the MTF curves in the meridian direction and the sagittal direction can achieve the best imaging effect and the lower the distortion rate. In actual tests, the closer the ordinates corresponding to the same abscissa are, the closer the MTF curves in the meridian direction and the sagittal direction are; at the same time, from the perspective of actual imaging, the closer the ordinates corresponding to the same abscissa in the test situation are to the ordinates corresponding to the same abscissa in the ideal situation, the better the imaging efficiency, the image tends to be real, and the distortion rate of the image is lower.

[0136] Refer to Figures 25 to 29 as shown, Figures 25 to 29 which respectively show the spherical aberration, coma, astigmatism, field curvature, distortion, longitudinal chromatic aberration, and lateral chromatic aberration of the optical system 100 corresponding to Embodiment 1 to Embodiment 5. From Figures 25 to 29 it can be seen that for the optical system 100 disclosed in the present invention, at working distances of 301 mm, 400 mm, 600 mm, 800 mm, and 1000 mm, various aberrations of the image plane are far less than 0.005 mm (the grid lines are equally spaced at 0.005 mm).

[0137] Refer to Figures 30 to 34 as shown, Figures 30 to 34 which respectively show the simulated imaging diagrams of the optical system 100 corresponding to Embodiment 1 to Embodiment 5. From Figures 30 to 34 it can be seen that for the optical system 100 disclosed in the present invention, at working distances of 301 mm, 400 mm, 600 mm, 800 mm, and 1000 mm, both the center of the field of view and the edge of the field of view can ensure good imaging quality.

[0138] Based on the same inventive concept, the present invention also discloses a surgical microscope (not shown). The surgical microscope includes: the optical system 100 disclosed above. For the structure of the optical system 100, reference can be made to the foregoing description, and details are not repeated herein.

[0139] In summary, the optical system 100 disclosed in the present invention can meet the requirements of different working distances, and can reduce the problem of prolonging the surgical time caused by replacing the objective lens group 10; the objective lens group 10 realizes a working distance range of 301 - 1000 mm and a focal length change range of 415 - 1024.2205 mm to adapt to special microscopic imaging scenarios, such as when the horizontal height of the operating table cannot be adjusted, so this requirement can be achieved through the working distance of the surgical microscope; it maintains high numerical MTF, low aberration, and high-resolution imaging at each working distance, and has good optical performance.

[0140] The series of detailed descriptions listed above are only specific descriptions of the feasible implementation manners of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent implementation manners or changes made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

[0141] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0142] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An optical system, characterized in that, The optical system includes: The objective lens assembly is used to receive light rays from the object surface and form parallel light rays for emission. A continuous zoom lens group is positioned on the image side of the objective lens group to receive the parallel light and perform zoom imaging; The objective lens assembly includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the object side. The first lens and the fifth lens both have negative optical power, while the second lens, the third lens, and the fourth lens all have positive optical power. The first lens and the second lens are cemented together to form a first cemented lens, wherein the object-side surface of the first cemented lens is concave and the image-side surface is convex. The third lens is a biconvex lens. The fourth lens and the fifth lens are cemented together to form a second cemented lens, wherein the object-side surface of the second cemented lens is convex and the image-side surface is concave. The continuous zoom lens group includes: a third cemented lens with positive optical power, a fourth cemented lens with negative optical power, an aperture stop, a fifth cemented lens with negative optical power, and a sixth cemented lens with positive optical power, arranged sequentially along the optical axis from the object side. The third cemented lens includes a sixth lens with positive optical power and a seventh lens with negative optical power, arranged sequentially along the optical axis from the object side. The fourth cemented lens includes an eighth lens with negative optical power and a ninth lens with positive optical power, arranged sequentially along the optical axis from the object side. The fifth cemented lens includes a tenth lens with positive optical power and an eleventh lens with negative optical power, arranged sequentially along the optical axis from the object side. The sixth cemented lens includes a twelfth lens with positive optical power and a thirteenth lens with positive optical power, arranged sequentially along the optical axis from the object side. The objective lens assembly satisfies the following relationship: ； ； Wherein, F refers to the focal length of the objective lens group, and f 12 This refers to the focal length of the first cemented lens, f. 345 It refers to the combined focal length of the third lens and the second cemented lens, M refers to the distance between the image-side surface of the second lens and the object-side surface of the third lens, WD refers to the working distance of the optical system, and v2 refers to the image distance between the third lens and the second cemented lens.

2. The optical system according to claim 1, characterized in that, The third cemented mirror has a convex object-side surface and a concave image-side surface; the fourth cemented mirror has a concave object-side surface and a convex image-side surface; the fifth cemented mirror has a concave object-side surface and a convex image-side surface; and the sixth cemented mirror has a convex object-side surface and a concave image-side surface.

3. The optical system according to claim 2, characterized in that, The object-side surface of the sixth lens is convex and the image-side surface is concave, while both the object-side and image-side surfaces of the seventh lens are convex. The object-side surface of the eighth lens is concave and the image-side surface is convex, while both the object-side surface and the image-side surface of the ninth lens are concave. The object-side surface and image-side surface of the tenth lens are both concave, while the object-side surface of the eleventh lens is convex and the image-side surface is concave. The object-side surface and image-side surface of the twelfth lens are both convex, while the object-side surface of the thirteenth lens is concave and the image-side surface is convex.

4. The optical system according to claim 1, characterized in that, The optical system includes a continuous zoom lens group, the optical axis of which is offset from the optical axis of the objective lens group.

5. The optical system according to claim 1, characterized in that, The optical system includes two continuous zoom lens groups, and the two optical axes of the two continuous zoom lens groups are symmetrically arranged from the optical axis of the objective lens group.

6. The optical system according to claim 1, characterized in that, The Abbe number V1 of the first lens and the Abbe number V2 of the second lens satisfy... ; The Abbe number V3 of the third lens satisfies ; The Abbe number V4 of the fourth lens and the Abbe number V5 of the fifth lens satisfy the following conditions: .

7. The optical system according to claim 1, characterized in that, The refractive index n1 of the first lens satisfies ; The refractive index n1 of the first lens and the refractive index n2 of the second lens satisfy the following conditions: ; The refractive index n3 of the third lens satisfies ; The refractive index n4 of the fourth lens satisfies ; The refractive index n4 of the fourth lens and the refractive index n5 of the fifth lens satisfy the following conditions: .

8. The optical system according to claim 1, characterized in that, The diameter of the objective lens group is larger than the diameter of any single lens in the continuous zoom lens group.

9. A surgical microscope, characterized in that, include: The optical system as described in any one of claims 1 to 8.

10. An adjustment method, characterized in that, The adjustment method for adjusting the optical system as described in any one of claims 1 to 8 includes: The focal length of the objective lens group is adjusted by adjusting the distance between the image-side surface of the second lens and the object-side surface of the third lens, thereby adapting to different working distance requirements of the optical system.

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