Microscope objective

Abstract

The present application relates to the field of optical lens, disclose a kind of microscope objective, the microscope objective sequentially includes from object side to image side: first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens and ninth lens;And satisfy the following relationship: 0.19≤WD / TTL≤0.36;4.00≤NA*f≤8.00;7.00≤f678 / f9≤16.00;-10.00≤(R17+R18) / (R17-R18)≤-1.50.The microscope objective of the present application has good imaging quality of optical performance, while meeting the requirements of wider working waveband and higher magnification.

Description

[Technical Field]

[0001] This invention relates to the field of optical lenses, and in particular to a microscope objective lens suitable for industrial microscopes. [Background Technology]

[0002] Microscope objectives can perform specific imaging functions using a certain field of view, focal length, and relative aperture. However, due to the limitations of optical imaging principles, these optical parameters are interdependent. Microscope objectives need to possess the characteristic of high resolution due to a large numerical aperture. However, the higher the magnification of a microscope objective and the larger its numerical aperture, the more significant the impact of thickness and refractive index changes on the microscope's imaging quality. It is usually difficult to simultaneously achieve high imaging quality and high magnification. Furthermore, with the development of technology and the increasing diversity of user needs, the requirements for system imaging quality are constantly improving, and nine-element lens structures are gradually appearing in lens designs. There is an urgent need for microscope objectives with good optical performance, a wide operating wavelength, and high magnification. [Summary of the Invention]

[0003] To address the aforementioned problems, the present invention aims to provide a microscope objective that can achieve good imaging quality while meeting the requirements of a wide operating wavelength and high magnification.

[0004] To solve the above-mentioned technical problems, embodiments of the present invention provide a microscope objective lens, which comprises, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens.

[0005] The distance from the object side of the first lens to the observed object is WD, the total optical length of the microscope objective is TTL, the object-side numerical aperture of the microscope objective is NA, the focal length of the microscope objective is f, the equivalent focal lengths of the sixth, seventh, and eighth lenses are f678, the focal length of the ninth lens is f9, the radius of curvature of the object side of the ninth lens is R17, and the radius of curvature of the image side of the ninth lens is R18, satisfying the following relationship:

[0006] 0.19≤WD / TTL≤0.36;

[0007] 4.00≤NA×f≤8.00;

[0008] 7.00≤f678 / f9≤16.00;

[0009] -10.00≤(R17+R18) / (R17-R18)≤-1.50.

[0010] Preferably, the refractive index of the second lens is n2, and it satisfies the following relationship:

[0011] n2≥2.00.

[0012] Preferably, the focal length of the third lens is f3, and it satisfies the following relationship:

[0013] 3.00≤f3 / f≤6.00.

[0014] Preferably, the first lens has negative refractive power, the object side of the first lens is concave near the axis, and the image side of the first lens is concave near the axis.

[0015] The focal length of the first lens is f1, the radius of curvature of the object-side surface of the first lens is R1, the radius of curvature of the image-side surface of the first lens is R2, and the axial thickness of the first lens is d1, and the following relationship is satisfied:

[0016] -2.20≤f1 / f≤-0.70;

[0017] -0.42≤(R1+R2) / (R1-R2)≤-0.16;

[0018] 0.01≤d1 / TTL≤0.02.

[0019] Preferably, the second lens has positive refractive power, and the object-side surface of the second lens is convex at the paraxial position;

[0020] The second lens has a focal length of f2, a radius of curvature of R3 on the object side, a radius of curvature of R4 on the image side, and an axial thickness of d3, and satisfies the following relationship:

[0021] 1.58 ≤ f² / f ≤ 11.25;

[0022] -1.85≤(R3+R4) / (R3-R4)≤-0.49;

[0023] 0.01≤d3 / TTL≤0.05.

[0024] Preferably, the third lens has positive refractive power, the object-side surface of the third lens is concave near the axis, and the image-side surface of the third lens is convex near the axis.

[0025] The object-side radius of curvature of the third lens is R5, the image-side radius of curvature of the third lens is R6, and the axial thickness of the third lens is d5, satisfying the following relationship:

[0026] 4.50≤(R5+R6) / (R5-R6)≤34.00;

[0027] 0.15≤d5 / TTL≤0.17.

[0028] Preferably, the fourth lens has negative refractive power, and the image-side surface of the fourth lens is concave at the paraxial position;

[0029] The fourth lens has a focal length of f4 and an on-axis thickness of d7, and satisfies the following relationship:

[0030] -54.00≤f4 / f≤-2.68;

[0031] 0.02≤d7 / TTL≤0.15.

[0032] Preferably, the fifth lens has positive refractive power, the object side of the fifth lens is convex at the paraxial position, and the image side of the fifth lens is convex at the paraxial position.

[0033] The fifth lens has a focal length of f5, a radius of curvature of R9 on the object side, a radius of curvature of R10 on the image side, and an axial thickness of d9, and satisfies the following relationship:

[0034] 1.80≤f5 / f≤9.03;

[0035] -0.13≤(R9+R10) / (R9-R10)≤0.09;

[0036] 0.05≤d9 / TTL≤0.07.

[0037] Preferably, the sixth lens has positive refractive power, the object-side surface of the sixth lens is convex at the paraxial position, and the image-side surface of the sixth lens is convex at the paraxial position.

[0038] The sixth lens has a focal length of f6, a radius of curvature of R11 on the object side, a radius of curvature of R12 on the image side, and an axial thickness of d11, and satisfies the following relationship:

[0039] 2.07≤f6 / f≤8.00;

[0040] -0.39≤(R11+R12) / (R11-R12)≤-0.14;

[0041] 0.07≤d11 / TTL≤0.12.

[0042] Preferably, the seventh lens has negative refractive power, the object-side surface of the seventh lens is concave at the paraxial position, and the image-side surface of the seventh lens is concave at the paraxial position.

[0043] The seventh lens has a focal length of f7, a radius of curvature of R13 on the object side, a radius of curvature of R14 on the image side, and an axial thickness of d13, and satisfies the following relationship:

[0044] -2.09≤f7 / f≤-1.09;

[0045] 0.11≤(R13+R14) / (R13-R14)≤0.38;

[0046] 0.01≤d13 / TTL≤0.02.

[0047] Preferably, the object-side surface of the eighth lens is convex at the paraxial position, and the image-side surface of the eighth lens is convex at the paraxial position.

[0048] The eighth lens has a focal length of f8, a central radius of curvature of R15 on the object side, a central radius of curvature of R16 on the image side, and an axial thickness of d15, and satisfies the following relationship:

[0049] -9.96≤f8 / f≤2.36;

[0050] -0.55≤(R15+R16) / (R15-R16)≤-0.31;

[0051] 0.02≤d15 / TTL≤0.07.

[0052] Preferably, the ninth lens has positive refractive power, the object side of the ninth lens is convex at the paraxial position, and the image side of the ninth lens is concave at the paraxial position.

[0053] The ninth lens has a focal length of f9, and the eighth lens has an on-axis thickness of d17, satisfying the following relationship:

[0054] 1.77≤f9 / f≤2.31;

[0055] 0.06≤d17 / TTL≤0.13.

[0056] Preferably, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are all made of glass.

[0057] The beneficial effects of the present invention are as follows: the microscope objective lens according to the present invention has good optical performance in terms of imaging quality, while meeting the requirements of a wide working wavelength and high magnification, and is especially suitable for industrial microscopes. [Attached Image Description]

[0058] Figure 1 This is a schematic diagram of the microscope objective lens according to the first embodiment of the present invention;

[0059] Figure 2 yes Figure 1 A schematic diagram of axial aberrations of the microscope objective lens shown.

[0060] Figure 3 yes Figure 1 The diagram shows the chromatic aberration at magnification of the microscope objective lens.

[0061] Figure 4 yes Figure 1 A schematic diagram of the field curvature and distortion of the microscope objective lens shown.

[0062] Figure 5 This is a schematic diagram of the structure of the microscope objective lens according to the second embodiment of the present invention;

[0063] Figure 6 yes Figure 5 A schematic diagram of axial aberrations of the microscope objective lens shown.

[0064] Figure 7 yes Figure 5 The diagram shows the chromatic aberration at magnification of the microscope objective lens.

[0065] Figure 8 yes Figure 5 A schematic diagram of the field curvature and distortion of the microscope objective lens shown.

[0066] Figure 9 This is a schematic diagram of the microscope objective lens according to the third embodiment of the present invention;

[0067] Figure 10 yes Figure 9 A schematic diagram of axial aberrations of the microscope objective lens shown.

[0068] Figure 11 yes Figure 9 The diagram shows the chromatic aberration at magnification of the microscope objective lens.

[0069] Figure 12 yes Figure 9 The diagram shows the field curvature and distortion of the microscope objective.

Detailed Implementation Methods

[0070] To make the objectives, technical solutions, and advantages of this invention clearer, the various embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this invention to facilitate a better understanding of the invention. However, the technical solutions claimed in this invention can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0071] (First Implementation)

[0072] Referring to the accompanying drawings, the present invention provides a microscope objective lens 10. Figure 1 The image shows a microscope objective 10 according to a first embodiment of the present invention. The microscope objective 10 includes nine lenses. Specifically, the microscope objective 10, from the object side to the image side, includes, in sequence: a first lens L1, a second lens L2, an aperture S1, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9. An optical filter or other optical element may be disposed between the ninth lens L9 and the image plane S1.

[0073] The distance from the object side of the first lens L1 to the observed object is defined as WD, and the total optical length of the microscope objective is defined as TTL. 0.19≤WD / TTL≤0.36 specifies the ratio of the distance WD from the object side of the first lens L1 to the observed object to the total optical length TTL. Within the range of the condition, an appropriate distance between the microscope objective 10 and the observed object can be guaranteed, so that the microscope objective 10 has good operability. At the same time, it allows for reasonable space to configure the lens of the microscope objective 10 to correct aberrations.

[0074] The numerical aperture of the microscope objective 10 is defined as NA, and the focal length of the microscope objective 10 is defined as f. 4.00≤NA*f≤8.00 specifies the range of the product of the numerical aperture NA and the focal length f. Within the range of the condition, the magnification of the microscope objective 10 can be maintained, and a wider field of view can be obtained.

[0075] The equivalent focal lengths of the sixth lens L6, the seventh lens L7, and the eighth lens L8 are defined as f678, and the focal length of the ninth lens L9 is defined as f9. 7.00≤f678 / f9≤16.00 defines the ratio of the focal length of the second lens group on the object side, i.e., the equivalent focal length f678 of the sixth lens L6, the seventh lens L7, and the eighth lens L8, to the focal length f9 of the ninth lens. By reasonably allocating the optical focal length of the microscope objective 10, light can propagate smoothly, resulting in better imaging quality and lower sensitivity for the microscope objective 10.

[0076] The radius of curvature of the object side of the ninth lens L9 is defined as R17, and the radius of curvature of the image side of the ninth lens is defined as R18. -10.00≤(R17+R18) / (R17-R18)≤-1.50 defines the shape of the ninth lens L9, which can effectively control the degree of light deviation entering the microscope objective 10 and effectively reduce chromatic aberration, making the chromatic aberration |LC|≤1.0μm.

[0077] When the distance from the object side of the first lens L1 of the microscope objective 10 to the observed object, the total optical length, the object-side numerical aperture, the focal length of the microscope objective, the focal length of the related lens, the radius of curvature of the object side of the related lens, and the radius of curvature of the image side of the microscope objective 10 satisfy the above-mentioned relationship, the microscope objective 10 can have good optical performance, a wide working band, and a high magnification, so that the magnification reaches 10 or above.

[0078] The refractive index of the second lens L2 is defined as n2, and satisfies the following relationship: n2≥2.00. This specifies the refractive index of the second lens L2 of the microscope objective 10. The front lens of the microscope objective 10 is preferably made of a high refractive index material, which is beneficial to reducing the aperture of the front lens and improving the imaging quality of the microscope objective 10.

[0079] The focal length of the third lens L3 is defined as f3, satisfying the following relationship: 3.00 ≤ f3 / f ≤ 6.00. This defines the ratio of the focal length f3 of the third lens L3 to the focal length f of the microscope objective 10. Within this condition, the degree of refraction of light entering the first lens group on the image side can be effectively controlled, and the distortion of the microscope objective 10 can be effectively controlled, ensuring that the distortion |Distortion| ≤ 0.7%, thus guaranteeing that the image remains undistorted under a large field of view. In this embodiment, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, and the ninth lens L9 are all made of glass.

[0080] In this embodiment, the object-side surface of the first lens L1 is concave near the axis, and the image-side surface is also concave near the axis, thus the first lens L1 has negative refractive power. In other optional embodiments, the object-side surface and image-side surface of the first lens L1 can also be configured with other concave and convex distributions, and the first lens L1 can also have positive refractive power.

[0081] The focal length of the first lens L1 is f1, and it satisfies the following relationship: -2.20≤f1 / f≤-0.70. Through the reasonable allocation of optical power, the system has better imaging quality and lower sensitivity.

[0082] The radius of curvature of the object side of the first lens L1 is R1, and the radius of curvature of the image side of the first lens L1 is defined as R2, and the following relationship is satisfied: -0.42≤(R1+R2) / (R1-R2)≤-0.16. By reasonably controlling the shape of the first lens, the first lens can effectively correct the spherical aberration of the system.

[0083] The on-axis thickness of the first lens L1 is d1, and it satisfies the following relationship: 0.01≤d1 / TTL≤0.02, which is beneficial for controlling the lens thickness and the total length of the lens.

[0084] In this embodiment, the object-side surface of the second lens L2 is convex near the axis, and the image-side surface is concave near the axis, thus the second lens L2 has positive refractive power. In other optional embodiments, the object-side and image-side surfaces of the second lens L2 can also be configured with other concave and convex distributions, and the second lens L2 can also have negative refractive power.

[0085] The focal length of the second lens L2 is f2, and it satisfies the following relationship: 1.58≤f2 / f≤11.25. Through the reasonable allocation of optical power, the system has better imaging quality and lower sensitivity.

[0086] The radius of curvature of the object side of the second lens L2 is R3, and the radius of curvature of the image side of the second lens L2 is R4, and they satisfy the following relationship: -1.85≤(R3+R4) / (R3-R4)≤-0.49, which defines the shape of the second lens L2. Within the range specified by the condition, the degree of refraction of light passing through the lens can be mitigated, and aberrations can be effectively reduced.

[0087] The on-axis thickness of the second lens L2 is d3, and it satisfies the following relationship: 0.01≤d3 / TTL≤0.05, which is beneficial for controlling the lens thickness and the total length of the lens.

[0088] In this embodiment, the object-side surface of the third lens L3 is concave near the axis, and the image-side surface is convex near the axis, thus the third lens L3 has positive refractive power. In other optional embodiments, the object-side and image-side surfaces of the third lens L3 can also be configured with other concave and convex distributions, and the third lens L3 can also have negative refractive power.

[0089] The object-side radius of curvature of the third lens L3 is R5, and the image-side radius of curvature of the third lens L3 is R6, and the following relationship is satisfied: 4.50≤(R5+R6) / (R5-R6)≤34.00, which specifies the shape of the third lens L3. Within the range specified by the condition, the degree of light deflection after passing through the lens can be mitigated, and aberrations can be effectively reduced.

[0090] The on-axis thickness of the third lens L3 is d5, and it satisfies the following relationship: 0.15≤d5 / TTL≤0.17, which is beneficial for controlling the lens thickness and the total length of the lens.

[0091] In this embodiment, the object-side surface of the fourth lens L4 is convex near the axis, and the image-side surface is concave near the axis, thus the fourth lens L4 has negative refractive power. In other optional embodiments, the object-side and image-side surfaces of the fourth lens L4 can also be configured with other concave and convex distributions, and the fourth lens L4 can also have positive refractive power.

[0092] The focal length of the fourth lens L4 is f4, and it satisfies the following relationship: -54.00≤f4 / f≤-2.68, which specifies the ratio of the focal length f4 of the fourth lens L4 to the focal length f of the system. Within the range of the condition, it helps to improve the performance of the optical system.

[0093] The on-axis thickness of the fourth lens L4 is d7, and it satisfies the following relationship: 0.02≤d7 / TTL≤0.15, which is beneficial for controlling the lens thickness and the total length of the lens.

[0094] In this embodiment, the object-side surface of the fifth lens L5 is convex near the axis, and the image-side surface is also convex near the axis, thus the fifth lens L5 has positive refractive power. In other optional embodiments, the object-side surface and image-side surface of the fifth lens L5 can also be configured with other concave and convex distributions, and the fifth lens L5 can also have negative refractive power.

[0095] The focal length of the fifth lens L5 is f5, and it satisfies the following relationship: 1.80≤f5 / f≤9.03. This specifies the ratio of the focal length f5 of the fifth lens L5 to the focal length f of the system, which helps to improve the performance of the optical system within the range of the condition.

[0096] The radius of curvature of the object side of the fifth lens L5 is R9, and the radius of curvature of the image side of the fifth lens L5 is R10, and the following relationship is satisfied: -0.13≤(R9+R10) / (R9-R10)≤0.09. This specifies the shape of the fifth lens L5. Within the range specified by the condition, the degree of refraction of light passing through the lens can be mitigated, and aberrations can be effectively reduced.

[0097] The on-axis thickness of the fifth lens L5 is d9, and it satisfies the following relationship: 0.05≤d9 / TTL≤0.07, which is beneficial for controlling the lens thickness and the overall length of the lens.

[0098] In this embodiment, the object-side surface of the sixth lens L6 is convex near the axis, and the image-side surface is also convex near the axis, thus the sixth lens L6 has positive refractive power. In other optional embodiments, the object-side surface and image-side surface of the sixth lens L6 can also be configured with other concave and convex distributions, and the sixth lens L6 can also have negative refractive power.

[0099] The focal length of the sixth lens L6 is f6, and it satisfies the following relationship: 2.07≤f6 / f≤8.00. This specifies the ratio of the focal length f6 of the sixth lens L6 to the focal length f of the system. Within the range of the condition, this helps to improve the performance of the optical system.

[0100] The radius of curvature of the object side of the sixth lens L6 is R11, and the radius of curvature of the image side of the sixth lens L6 is R12, and they satisfy the following relationship: -0.39≤(R11+R12) / (R11-R12)≤-0.14. This specifies the shape of the sixth lens L6. Within the range specified by the condition, it can mitigate the degree of light deflection after passing through the lens and effectively reduce aberrations.

[0101] The on-axis thickness of the sixth lens L6 is d11, and it satisfies the following relationship: 0.07≤d11 / TTL≤0.12, which is beneficial for controlling the lens thickness and the total length of the lens.

[0102] In this embodiment, the object-side surface of the seventh lens L7 is concave near the axis, and the image-side surface is also concave near the axis, thus the seventh lens L7 has negative refractive power. In other optional embodiments, the object-side and image-side surfaces of the seventh lens L7 can also be configured with other concave and convex distributions, and the seventh lens L7 can also have positive refractive power.

[0103] The focal length of the seventh lens L7 is f7, and it satisfies the following relationship: -2.09≤f7 / f≤-1.09. This specifies the ratio of the focal length f7 of the seventh lens L7 to the focal length f of the system. Within the range of the condition, this helps to improve the performance of the optical system.

[0104] The radius of curvature of the object side of the seventh lens L7 is R13, and the radius of curvature of the image side of the seventh lens L7 is R14, satisfying the following relationship: 0.11≤(R13+R14) / (R13-R14)≤0.38. This specifies the shape of the seventh lens L7. Within the range specified by the condition, it can mitigate the degree of light refraction after passing through the lens, effectively reducing aberrations.

[0105] The on-axis thickness of the seventh lens L7 is d13, and it satisfies the following relationship: 0.01≤d13 / TTL≤0.02, which is beneficial for controlling the lens thickness and the total length of the lens.

[0106] In this embodiment, the object-side surface of the eighth lens L8 is convex near the axis, and the image-side surface is concave near the axis, thus the eighth lens L8 has positive refractive power. In other optional embodiments, the object-side and image-side surfaces of the eighth lens L8 can also be configured with other concave and convex distributions, and the eighth lens L8 can also have negative refractive power.

[0107] The focal length of the eighth lens L8 is f8, and it satisfies the following relationship: -9.96≤f8 / f≤2.36. This specifies the ratio of the focal length f8 of the eighth lens L8 to the focal length f of the system. Within the range of the condition, this helps to improve the performance of the optical system.

[0108] The central radius of curvature of the object-side surface of the eighth lens L8 is R15, and the central radius of curvature of the image-side surface of the seventh lens is R16, satisfying the following relationship: -0.55≤(R15+R16) / (R15-R16)≤-0.31. This specifies the shape of the eighth lens L8. Within the range specified by the condition, it can mitigate the degree of light refraction through the lens, effectively reducing aberrations.

[0109] The on-axis thickness of the eighth lens L8 is d15, and it satisfies the following relationship: 0.02≤d15 / TTL≤0.07, which is beneficial for controlling the lens thickness and the total length of the lens.

[0110] In this embodiment, the object-side surface of the ninth lens L9 is convex near the axis, and the image-side surface is concave near the axis, thus the ninth lens L9 has positive refractive power. In other optional embodiments, the object-side and image-side surfaces of the ninth lens L9 can also be configured with other concave and convex distributions, and the ninth lens L9 can also have negative refractive power.

[0111] The focal length of the ninth lens L9 is f9, and it satisfies the following relationship: 1.77≤f9 / f≤2.31. This specifies the ratio of the focal length f9 of the ninth lens L9 to the focal length f of the system. Within the range of the condition, this helps to improve the performance of the optical system.

[0112] The on-axis thickness of the ninth lens L9 is d17, and it satisfies the following relationship: 0.06≤d17 / TTL≤0.13, which is beneficial for controlling the lens thickness and the overall length of the lens.

[0113] In this embodiment, the microscope objective and the tube lens are used together, and the focal length of the tube lens is 200.00 mm.

[0114] The microscope objective lens 10 of the present invention will be described below with examples. The symbols used in each example are shown below. The units for focal length, on-axis distance, radius of curvature, and on-axis thickness are mm.

[0115] TTL: Optical Length (axial distance from the object surface of the first lens L1 to the imaging surface), in mm;

[0116] Preferably, the object-side and / or image-side surfaces of the lens may also be provided with inflection points and / or stagnation points to meet the requirements of high-quality imaging. Specific possible implementation schemes are described below.

[0117] Table 1 shows the design data of the microscope objective 10 according to the first embodiment of the present invention.

[0118] Table 1

[0119]

[0120]

[0121] The meanings of each symbol are as follows.

[0122] S1: Aperture;

[0123] R: Radius of curvature of the optical surface; for lenses, it is the central radius of curvature.

[0124] R1: The radius of curvature of the object-side surface of the first lens L1;

[0125] R2: The radius of curvature of the image-side surface of the first lens L1;

[0126] R3: The radius of curvature of the object-side surface of the second lens L2;

[0127] R4: Radius of curvature of the image-side surface of the second lens L2;

[0128] R5: The radius of curvature of the object-side surface of the third lens L3;

[0129] R6: Radius of curvature of the image-side surface of the third lens L3;

[0130] R7: The radius of curvature of the object-side surface of the fourth lens L4;

[0131] R8: Radius of curvature of the image-side surface of the fourth lens L4;

[0132] R9: The radius of curvature of the object-side surface of the fifth lens L5;

[0133] R10: Radius of curvature of the image-side surface of the fifth lens L5;

[0134] R11: The radius of curvature of the object-side surface of the sixth lens L6;

[0135] R12: Radius of curvature of the image-side surface of the sixth lens L6;

[0136] R13: The radius of curvature of the object-side surface of the seventh lens L7;

[0137] R14: Radius of curvature of the image-side surface of the seventh lens L7;

[0138] R15: The radius of curvature of the object-side surface of the eighth lens L8;

[0139] R16: Radius of curvature of the image-side surface of the eighth lens L8;

[0140] R17: Radius of curvature of the object-side surface of the ninth lens L9;

[0141] R18: Radius of curvature of the image-side surface of the ninth lens L9;

[0142] d: The axial thickness of the lens and the axial distance between lenses;

[0143] d0: The on-axis distance from aperture S1 to the object-side surface of the first lens L1;

[0144] d1: On-axis thickness of the first lens L1;

[0145] d2: On-axis distance from the image-side surface of the first lens L1 to the object-side surface of the second lens L2; ​​d3: On-axis thickness of the second lens L2;

[0146] d4: The axial distance from the image-side surface of the second lens L2 to the object-side surface of the third lens L3;

[0147] d5: On-axis thickness of the third lens L3;

[0148] d6: The on-axis distance from the image-side surface of the third lens L3 to the object-side surface of the fourth lens L4;

[0149] d7: On-axis thickness of the fourth lens L4;

[0150] d8: The on-axis distance from the image-side surface of the fourth lens L4 to the object-side surface of the fifth lens L5;

[0151] d9: On-axis thickness of the fifth lens L5;

[0152] d10: The axial distance from the image-side surface of the fifth lens L5 to the object-side surface of the sixth lens L6;

[0153] d11: On-axis thickness of the sixth lens L6;

[0154] d12: The axial distance from the image-side surface of the sixth lens L6 to the object-side surface of the seventh lens L7;

[0155] d13: On-axis thickness of the seventh lens L7;

[0156] d14: The axial distance from the image-side surface of the seventh lens L7 to the object-side surface of the eighth lens L8;

[0157] d15: On-axis thickness of the eighth lens L8;

[0158] d16: The on-axis distance from the image-side surface of the eighth lens L8 to the object-side surface of the ninth lens L9;

[0159] d17: On-axis thickness of the ninth lens L9;

[0160] d18: The axial distance from the image-side surface of the ninth lens L9 to the object-side surface of the optical filter;

[0161] nd: Refractive index of the d-line;

[0162] nd1: The refractive index of the d-line of the first lens L1;

[0163] nd2: The refractive index of the d-line of the second lens L2;

[0164] nd3: The refractive index of the d-line of the third lens L3;

[0165] nd4: The refractive index of the d-line of the fourth lens L4;

[0166] nd5: The refractive index of the d-line of the fifth lens L5;

[0167] nd6: The refractive index of the d-line of the sixth lens L6;

[0168] nd7: The refractive index of the d-line of the seventh lens L7;

[0169] nd8: The refractive index of the d-line of the eighth lens L8;

[0170] nd9: The refractive index of the d-line of the ninth lens L9;

[0171] vd: Abbe number;

[0172] v1: Abbe number of the first lens L1;

[0173] v2: Abbe number of the second lens L2;

[0174] v3: Abbe number of the third lens L3;

[0175] v4: Abbe number of the fourth lens L4;

[0176] v5: Abbe number of the fifth lens L5;

[0177] v6: Abbe number of the sixth lens L6;

[0178] v7: Abbe number of the seventh lens L7;

[0179] v8: Abbe number of the eighth lens L8;

[0180] v9: Abbe number of the ninth lens L9.

[0181] Figure 2 , Figure 3 Axial aberration and magnification chromatic aberration are shown respectively after light with wavelengths of 700nm, 656nm, 588nm, 520nm, 486nm and 435nm passes through the microscope objective lens 10 of the first embodiment. Figure 4 This shows a schematic diagram of the field curvature and distortion of light with a wavelength of 656 nm after passing through the microscope objective lens 10 of the first embodiment. Figure 4 The field curvature S is the field curvature in the sagittal direction, and T is the field curvature in the meridional direction.

[0182] Table 4, which appears later, shows the values ​​corresponding to the various numerical values ​​and the parameters specified in the conditional expressions for each of Examples 1, 2, and 3.

[0183] As shown in Table 4, the first embodiment satisfies all the conditional expressions.

[0184] In this embodiment, the microscope objective lens has an entrance pupil diameter of 12.6 mm, a full field-of-view image height of 1.5 mm, a diagonal field of view of 8.62°, an object-side numerical aperture (NA) of 0.30, a magnification of 10x, and a working wavelength range of 486 nm to 700 nm, exhibiting excellent optical performance.

[0185] (Second Implementation)

[0186] The second implementation method is basically the same as the first implementation method, and the symbols have the same meanings as the first implementation method. Only the differences are listed below.

[0187] In this embodiment, the image-side surface of the second lens L2 is convex at the paraxial position, and the eighth lens L8 has negative refractive power.

[0188] Table 2 shows the design data of the microscope objective 20 according to the second embodiment of the present invention.

[0189] Table 2

[0190]

[0191] Figure 6 , Figure 7 Axial aberration and magnification chromatic aberration are shown respectively after light with wavelengths of 700nm, 656nm, 588nm, 520nm, 486nm and 435nm passes through the microscope objective lens 20 of the second embodiment. Figure 8 This shows a schematic diagram of the field curvature and distortion of light with a wavelength of 656 nm after passing through the microscope objective lens 20 of the second embodiment. Figure 8 The field curvature S is the field curvature in the sagittal direction, and T is the field curvature in the meridional direction.

[0192] Table 4, which appears later, shows the values ​​corresponding to the various numerical values ​​and the parameters specified in the conditional expressions for each of Examples 1, 2, and 3.

[0193] As shown in Table 4, the second embodiment satisfies all the conditional expressions.

[0194] In this embodiment, the microscope objective lens has an entrance pupil diameter of 8 mm, a full field-of-view image height of 1.5 mm, a diagonal field of view of 8.22°, an object-side numerical aperture (NA) of 0.19, a magnification of 10x, and a working wavelength range of 486 nm to 700 nm, exhibiting excellent optical performance.

[0195] (Third Implementation)

[0196] The third implementation method is basically the same as the first implementation method, and the symbols have the same meanings as the first implementation method. Only the differences are listed below.

[0197] In this embodiment, the object-side surface of the fourth lens L4 is concave near the axis, and the eighth lens L8 has negative refractive power.

[0198] Table 3 shows the design data of the microscope objective 30 according to the third embodiment of the present invention.

[0199] Table 3

[0200]

[0201] Figure 10 , Figure 11 Axial aberration and magnification chromatic aberration are shown respectively after light with wavelengths of 700nm, 656nm, 588nm, 520nm, 486nm and 435nm passes through the microscope objective lens 30 of the third embodiment. Figure 12 This illustrates the field curvature and distortion of light with a wavelength of 656 nm after passing through the microscope objective 30 of the third embodiment. Figure 12 The field curvature S is the field curvature in the sagittal direction, and T is the field curvature in the meridional direction.

[0202] Table 4, which appears later, shows the values ​​corresponding to the various numerical values ​​and the parameters specified in the conditional expressions for each of Examples 1, 2, and 3.

[0203] As shown in Table 4, the third embodiment satisfies all the conditional expressions.

[0204] In this embodiment, the microscope objective lens has an entrance pupil diameter of 16 mm, a full field-of-view image height of 1.5 mm, a diagonal field of view of 8.22°, an object-side numerical aperture (NA) of 0.38, a magnification of 10x, and a working wavelength range of 486 nm to 700 nm, exhibiting excellent optical performance.

[0205] Table 4

[0206] WD / TTL 0.28 0.19 0.36 NA*f 6.00 8.00 4.00 f678 / f9 11.91 7.00 16.00 (R17+R18) / (R17-R18) -2.72 -10.00 -1.50 f 20.014 21.015 21.000 f1 -14.925 -35.050 -45.848 f2 31.801 54.393 235.905 f3 80.693 126.016 62.991 f4 -53.682 -1128.356 -106.686 f5 36.134 150.002 189.526 f6 41.556 90.717 167.028 f7 -21.861 -43.885 -42.395 f8 47.211 -117.019 -209.094 f9 42.661 48.460 37.328 f12 507.914 -19.442 -16.096 NA 0.30 0.19 0.38

[0207] Where f12 is the combined focal length of the first lens and the second lens.

[0208] The above description is merely an embodiment of the present invention. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements all fall within the protection scope of the present invention.

Claims

1. A microscope objective, characterized in that The microscope has nine lenses, and the microscope objectives, from the object side to the image side, include the following lenses in sequence: first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, and ninth lens. The first lens has negative refractive power, and its object-side surface is concave paraxially, as is its image-side surface. The second lens has positive refractive power, and its object-side surface is convex paraxially. The third lens has positive refractive power, and its object-side surface is concave paraxially, as is its image-side surface. The fourth lens has negative refractive power, and its image-side surface is concave paraxially. The fifth lens has positive refractive power, and its object-side surface is convex paraxially. The image-side surface of the sixth lens is convex at the paraxial direction; the object-side surface of the sixth lens is convex at the paraxial direction, and the image-side surface of the sixth lens is convex at the paraxial direction; the seventh lens has negative refractive power, the object-side surface of the seventh lens is concave at the paraxial direction, and the image-side surface of the seventh lens is concave at the paraxial direction; the object-side surface of the eighth lens is convex at the paraxial direction, and the image-side surface of the eighth lens is convex at the paraxial direction; the ninth lens has positive refractive power, the object-side surface of the ninth lens is convex at the paraxial direction, and the image-side surface of the ninth lens is concave at the paraxial direction; The distance from the object side of the first lens to the observed object is WD, the total optical length of the microscope objective is TTL, the object-side numerical aperture of the microscope objective is NA, the focal length of the microscope objective is f, the equivalent focal lengths of the sixth, seventh, and eighth lenses are f678, the focal length of the ninth lens is f9, the radius of curvature of the object side of the ninth lens is R17, and the radius of curvature of the image side of the ninth lens is R18, satisfying the following relationship: 0.19≤WD / TTL≤0.36; 4.00≤NA×f≤8.00; 7.00≤f678 / f9≤16.00; -10.00≤(R17+R18) / (R17-R18)≤-1.

50.

2. The microscope objective according to claim 1, characterized in that The refractive index of the second lens is n2, and it satisfies the following relationship: n2≥2.00。 3. The microscope objective according to claim 1, characterized in that The focal length of the third lens is f3, and it satisfies the following relationship: 3.00≤f3 / f≤6.

00.

4. The microscope objective according to claim 1, characterized in that The focal length of the first lens is f1, the radius of curvature of the object-side surface of the first lens is R1, the radius of curvature of the image-side surface of the first lens is R2, and the axial thickness of the first lens is d1, and the following relationship is satisfied: -2.20≤f1 / f≤-0.70; -0.42≤(R1+R2) / (R1-R2)≤-0.16; 0.01≤d1 / TTL≤0.

02.

5. The microscope objective according to claim 1, characterized in that The second lens has a focal length of f2, a radius of curvature of R3 on the object side, a radius of curvature of R4 on the image side, and an axial thickness of d3, and satisfies the following relationship: 1.58 ≤ f² / f ≤ 11.25; -1.85≤(R3+R4) / (R3-R4)≤-0.49; 0.01≤d3 / TTL≤0.

05.

6. The microscope objective according to claim 1, characterized in that The object-side radius of curvature of the third lens is R5, the image-side radius of curvature of the third lens is R6, and the axial thickness of the third lens is d5, satisfying the following relationship: 4.50≤(R5+R6) / (R5-R6)≤34.00; 0.15≤d5 / TTL≤0.

17.

7. The microscope objective according to claim 1, characterized in that The fourth lens has a focal length of f4 and an on-axis thickness of d7, and satisfies the following relationship: -54.00≤f4 / f≤-2.68; 0.02≤d7 / TTL≤0.

15.

8. The microscope objective according to claim 1, characterized in that The fifth lens has a focal length of f5, a radius of curvature of R9 on the object side, a radius of curvature of R10 on the image side, and an axial thickness of d9, and satisfies the following relationship: 1.80≤f5 / f≤9.03; -0.13≤(R9+R10) / (R9-R10)≤0.09; 0.05≤d9 / TTL≤0.

07.

9. The microscope objective according to claim 1, characterized in that, The sixth lens has a focal length of f6, a radius of curvature of R11 on the object side, a radius of curvature of R12 on the image side, and an axial thickness of d11, and satisfies the following relationship: 2.07≤f6 / f≤8.00; -0.39≤(R11+R12) / (R11-R12)≤-0.14; 0.07≤d11 / TTL≤0.

12.

10. The microscope objective according to claim 1, characterized in that, The seventh lens has a focal length of f7, a radius of curvature of R13 on the object side, a radius of curvature of R14 on the image side, and an axial thickness of d13, and satisfies the following relationship: -2.09≤f7 / f≤-1.09; 0.11≤(R13+R14) / (R13-R14)≤0.38; 0.01≤d13 / TTL≤0.

02.

11. The microscope objective according to claim 1, characterized in that, The eighth lens has a focal length of f8, a central radius of curvature of R15 on the object side, a central radius of curvature of R16 on the image side, and an axial thickness of d15, and satisfies the following relationship: -9.96≤f8 / f≤2.36; -0.55≤(R15+R16) / (R15-R16)≤-0.31; 0.02≤d15 / TTL≤0.

07.

12. The microscope objective according to claim 1, characterized in that, The ninth lens has a focal length of f9, and the eighth lens has an on-axis thickness of d17, satisfying the following relationship: 1.77≤f9 / f≤2.31; 0.06≤d17 / TTL≤0.

13.

13. The microscope objective according to claim 1, characterized in that, The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are all made of glass.

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