A deep ultraviolet microscope optical system with large numerical aperture and long working distance

Abstract

A deep ultraviolet microscope optical system with a large numerical aperture and a long working distance relates to the field of optical imaging technology. In order to solve the technical problem in the prior art that the existing tube lens design is often difficult to perfectly match with the objective lens with a high numerical aperture, which limits the high-end microscope optical system, the technical solution provided by the present invention is: a deep ultraviolet microscope optical module with a large numerical aperture and a long working distance, the module comprising: a tube lens optical system and an objective lens optical system arranged coaxially; the tube lens optical system comprises a first lens group and a second lens group; the objective lens optical system comprises a third internal reflection lens group, a fourth lens group, a fifth lens group and a sixth internal reflection lens group. The system also comprises an image plane and an object plane arranged coaxially with the module. It is suitable for application in the design of microscope optical systems.

Description

Technical Field

[0001] The invention relates to the technical field of optical imaging, and in particular to a deep ultraviolet microscope optical system with a large numerical aperture and a long working distance. Background Art

[0002] Semiconductor chip processing is the cornerstone of modern electronic product manufacturing. The process includes multiple complex steps such as lithography, oxidation, ion implantation, etching and chemical mechanical polishing. Each step requires precise control to ensure that the final product can meet strict performance standards. Among them, lithography is a key step in chip processing, which transfers the design pattern to the silicon wafer. In this process, a high-resolution optical system is crucial because it directly affects the fineness and accuracy of the final pattern. As chip technology develops towards smaller processes (such as 7nm, 5nm and below), traditional visible light microscopes can no longer meet these precision requirements. Ultraviolet microscope optical systems have become an important tool to meet industry needs because of their shorter wavelengths, especially deep ultraviolet (generally referring to wavelengths between 200-300 nanometers) can achieve higher resolution, while deep ultraviolet light sources have relatively low energy efficiency, and usually use non-parallel light paths to reduce the number of lenses, thereby improving the transmittance of the system.

[0003] The deep ultraviolet microscope optical system with large numerical aperture and long working distance consists of two parts: the objective lens and the tube lens. The objective lens is the core component of the whole system, and its imaging performance directly affects the quality of sample information obtained by the microscope. With the continuous advancement of microscopic imaging technology, the objective lens is also facing higher requirements in terms of field of view and image quality. The design of the objective lens must not only have a large numerical aperture, but also maintain excellent imaging performance in the deep ultraviolet spectrum.

[0004] The tube lens is responsible for focusing the corrected beam of the objective lens onto the sensor. Compared with the objective lens, the tube lens has a lower demand for aberration correction, and its main goal is to achieve convenient and efficient imaging. However, most tube lenses on the market have fixed magnifications, which limits the user's flexible application of multiple magnifications and fields of view in actual operations. In addition, the current design of tube lenses is often difficult to perfectly match with high numerical aperture objectives, which further restricts the development of high-end microscopic optical systems.

[0005] Therefore, current technology urgently needs to develop a new type of microscopic optical system that can integrate large numerical aperture, deep ultraviolet wide spectrum characteristics, as well as multiple magnification and multi-field functions. Such a system will better meet the needs of users, especially in the field of high-end microscopic imaging applications, and promote the further development of microscopic optics. Summary of the invention

[0006] In order to solve the technical problem that the existing tube lens design is often difficult to perfectly match with the objective lens with high numerical aperture, which limits the high-end microscopic optical system, the technical solution provided by the present invention is as follows:

[0007] A deep ultraviolet microscope optical module with large numerical aperture and long working distance, the module comprising:

[0008] A tube lens optical system and an objective lens optical system arranged coaxially;

[0009] The tube lens optical system includes a first lens group and a second lens group;

[0010] The objective optical system comprises a third lens group, a fourth lens group, a fifth lens group and a sixth internally reflective lens group;

[0011] Among them, 0 <f A / f<30;-30 <f B / f<0;180 <f C / f<210;-10 <f D / f<20;-30 <f E / f<0;-20 <f F / f<10;

[0012] f is the focal length of the entire microscope optical module, f A is the focal length of the first lens group, f B is the focal length of the second lens group, f C is the focal length of the third lens group, f D is the focal length of the fourth lens group, f E is the focal length of the fifth lens group, f F is the focal length of the sixth internal reflection lens group.

[0013] Furthermore, a preferred embodiment is provided, wherein the first lens group, the second lens group, the third lens group, the fourth lens group, the fifth lens group and the sixth internally reflective lens group are arranged in sequence.

[0014] Further, a preferred embodiment is provided, wherein the first lens group includes five lenses arranged coaxially;

[0015] satisfy:

[0016] -25mm <f1<-5mm;90mm<f2<110mm;-140mm<f3<-120mm;130mm<f4<150mm;-160mm<f5<-140mm;

[0017] Among them, f1, f2, f3, f4 and f5 are the focal lengths of the five lenses respectively.

[0018] Further, a preferred embodiment is provided, wherein the second lens group includes three lenses arranged coaxially;

[0019] satisfy:

[0020] 250mm <f6<270mm;-170mm<f7<-150mm;210mm<f8<230mm;

[0021] Among them, f6, f7 and f8 are the focal lengths of the three lenses respectively.

[0022] Further, a preferred embodiment is provided, wherein the third lens group includes three lenses arranged coaxially;

[0023] satisfy:

[0024] 60mm <f9<80mm;-70mm<f 10 <-50mm; 130mm <f 11 <150mm;

[0025] Among them, f9, f 10 and f 11 are the focal lengths of the three lenses respectively.

[0026] Further, a preferred embodiment is provided, wherein the fourth lens group includes two lenses arranged coaxially;

[0027] satisfy:

[0028] 40mm <f 12 <60mm; -120mm <f 13 <-100mm;

[0029] Among them, f 12 and f 13 are the focal lengths of the two lenses respectively.

[0030] Further, a preferred embodiment is provided, wherein the fifth lens group includes five lenses arranged coaxially;

[0031] satisfy:

[0032] 20mm <f 14 <40mm; -50mm <f 15 <-30mm; 10mm <f 16 <30mm; 70mm <f 17 <90mm; 0mm <f 18 <20mm;

[0033] Among them, f 14 、f 15 、f 16 、f17 and f 18 are the focal lengths of the five lenses respectively.

[0034] Further, a preferred embodiment is provided, wherein the sixth internally reflective lens group comprises three lenses arranged coaxially;

[0035] satisfy:

[0036] 150mm <f 20 <170mm;

[0037] Among them, f 20 is the focal length of one of the lenses.

[0038] Based on the same inventive concept, the present invention also provides a deep ultraviolet microscope optical system with large numerical aperture and long working distance, the system comprising the module, and an image plane and an object plane coaxially arranged with the module.

[0039] Based on the same inventive concept, the present invention also provides a method for designing a deep ultraviolet microscope optical module with a large numerical aperture and a long working distance, which is used to design the module, comprising:

[0040] Steps for collecting design parameters of the microscope optical system;

[0041] The step of generating an initial configuration of the optical system according to the design parameters of the microscopic optical system;

[0042] Based on the initial parameters of the initial configuration of the optical system, the step of obtaining the focal length and the radius of curvature of each lens group by an optical simulation algorithm;

[0043] The step of outputting the focal length and curvature radius of each lens group in an editable file format.

[0044] Compared with the prior art, the technical solution provided by the present invention is beneficial in that:

[0045] By grouping the tube lens optical system and the objective lens optical system and adopting a combination of multiple lens groups, the numerical aperture of the microscope optical system is effectively improved while maintaining the characteristics of a long working distance. Compared with the existing system that only uses a single lens group, this design significantly improves the imaging resolution and optical performance, especially in deep ultraviolet band applications.

[0046] The first lens group is designed as a zoom group, and the focal length range is controlled within a specific ratio, which can achieve the stability of the optical performance of the microscope system at different magnifications. This zoom group design enables the system to maintain a high numerical aperture when adjusting the magnification, and has higher flexibility and imaging clarity compared to traditional fixed magnification optical systems.

[0047] The third lens group effectively reduces aberrations, especially chromatic aberration and spherical aberration, in the deep ultraviolet band, ensuring the consistency of imaging quality. Through the synergy of this lens group and other lens groups, the system still maintains good beam focusing ability at high numerical aperture, which is of great significance in high-resolution microscopic observation.

[0048] The introduction of the fifth lens group optimizes the spatial distribution of the light beam and adjusts the refraction angle of the light path, enabling the entire system to achieve clear imaging within a wider working distance range. Compared with existing short-working-distance microscopy optical systems, this design effectively expands the system's applicable scenarios, especially for complex experimental environments that require long-distance observation.

[0049] The focal length parameters of the sixth internal reflection lens group are designed within a specific range, further compensating for astigmatism and nonlinear errors in the optical path. This feature significantly improves the overall imaging stability of the system, making its optical performance in the deep ultraviolet band better than existing similar systems, meeting the needs of high-precision imaging.

[0050] It is suitable for use in the design of microscopic optical systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of the optical structure of a deep ultraviolet microscope optical system with a large numerical aperture and a long working distance;

[0052] Figure 2 It is a schematic diagram of the optical structure of the tube mirror optical system;

[0053] Figure 3 It is a schematic diagram of the optical structure of the objective optical system;

[0054] Figure 4 is a schematic diagram of the reflection surface of the sixth internally reflecting lens group;

[0055] Figure 5 It is the optical path diagram of the microscope system at different magnifications;

[0056] Figure 6 This is a graph of the field curvature of the microscope optical system at 250x magnification;

[0057] Figure 7 This is a diagram of the axial chromatic aberration of the microscope optical system at 250x magnification;

[0058] Figure 8 This is a graph of the field curvature of the microscope optical system at 150x magnification;

[0059] Fig. 9 This is a diagram of axial chromatic aberration of the microscope optical system at 150x magnification;

[0060] Fig.10This is a graph of the field curvature of the microscope optical system at 50x magnification;

[0061] Fig.11 This is a diagram of the axial chromatic aberration of the microscope optical system at 50x magnification;

[0062] Among them, A is the first lens group, B is the second lens group, C is the third lens group, D is the fourth lens group, E is the fifth lens group, F is the sixth internal reflection lens group, 1 is the first lens, 2 is the second lens, 3 is the third lens, 4 is the fourth lens, 5 is the fifth lens, 6 is the sixth lens, 7 is the seventh lens, 8 is the eighth lens, 9 is the ninth lens, 10 is the tenth lens, 11 is the eleventh lens, 12 is the twelfth lens, 13 is the thirteenth lens, 14 is the fourteenth lens, 15 is the fifteenth lens, 16 is the sixteenth lens, 17 is the seventeenth lens, 18 is the eighteenth lens, 19 is the nineteenth reflector, 20 is the twentieth lens, and 21 is the twenty-first internal reflection lens. DETAILED DESCRIPTION

[0063] In order to make the advantages and benefits of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention is now further described in detail in conjunction with the accompanying drawings, specifically:

[0064] Embodiment 1: This embodiment provides a deep ultraviolet microscope optical module with large numerical aperture and long working distance, and the module includes:

[0065] A tube lens optical system and an objective lens optical system arranged coaxially;

[0066] The tube lens optical system includes a first lens group A and a second lens group B;

[0067] The objective optical system comprises a third lens group C, a fourth lens group D, a fifth lens group E and a sixth internally reflective lens group F;

[0068] Among them, 0 <f A / f<30;-30 <f B / f<0;180 <f C / f<210;-10 <f D / f<20;-30 <f E / f<0;-20 <f F / f<10;

[0069] f is the focal length of the entire microscope optical module, f A is the focal length of the first lens group A, f B is the focal length of the second lens group B, f C is the focal length of the third lens group C, f D is the focal length of the fourth lens group D, f Eis the focal length of the fifth lens group E, f F is the focal length of the sixth internal reflection lens group F.

[0070] Embodiment 2. This embodiment is a further limitation of a deep ultraviolet large numerical aperture and long working distance microscope optical module provided in embodiment 1. The first lens group A, the second lens group B, the third lens group C, the fourth lens group D, the fifth lens group E and the sixth internal reflection lens group F are arranged in sequence.

[0071] Embodiment 3: This embodiment further defines a deep ultraviolet microscope optical module with large numerical aperture and long working distance provided in embodiment 1, wherein the first lens group A includes five lenses arranged coaxially;

[0072] satisfy:

[0073] -25mm <f1<-5mm;90mm<f2<110mm;-140mm<f3<-120mm;130mm<f4<150mm;-160mm<f5<-140mm;

[0074] Among them, f1, f2, f3, f4 and f5 are the focal lengths of the five lenses respectively.

[0075] Embodiment 4: This embodiment further defines a deep ultraviolet microscope optical module with large numerical aperture and long working distance provided in embodiment 1, wherein the second lens group B includes three lenses arranged coaxially;

[0076] satisfy:

[0077] 250mm <f6<270mm;-170mm<f7<-150mm;210mm<f8<230mm;

[0078] Among them, f6, f7 and f8 are the focal lengths of the three lenses respectively.

[0079] Embodiment 5: This embodiment further defines a deep ultraviolet microscope optical module with large numerical aperture and long working distance provided in embodiment 1, wherein the third lens group C includes three lenses arranged coaxially;

[0080] satisfy:

[0081] 60mm <f9<80mm;-70mm<f 10 <-50mm; 130mm <f 11 <150mm;

[0082] Among them, f9, f 10 and f 11 are the focal lengths of the three lenses respectively.

[0083] Embodiment 6: This embodiment further defines a deep ultraviolet microscope optical module with large numerical aperture and long working distance provided in embodiment 1, wherein the fourth lens group D includes two lenses arranged coaxially;

[0084] satisfy:

[0085] 40mm <f 12 <60mm; -120mm <f 13 <-100mm;

[0086] Among them, f 12 and f 13 are the focal lengths of the two lenses respectively.

[0087] Embodiment 7: This embodiment further defines a deep ultraviolet microscope optical module with large numerical aperture and long working distance provided in embodiment 1, wherein the fifth lens group E includes five lenses arranged coaxially;

[0088] satisfy:

[0089] 20mm <f 14 <40mm; -50mm <f 15 <-30mm; 10mm <f 16 <30mm; 70mm <f 17 <90mm; 0mm <f 18 <20mm;

[0090] Among them, f 14 、f 15 、f 16 、f 17 and f 18 are the focal lengths of the five lenses respectively.

[0091] Embodiment 8: This embodiment further defines a deep ultraviolet microscope optical module with large numerical aperture and long working distance provided in embodiment 1, wherein the sixth internal reflection lens group F includes three lenses arranged coaxially;

[0092] satisfy:

[0093] 150mm <f 20 <170mm;

[0094] Among them, f 20 is the focal length of one of the lenses.

[0095] Embodiment 9: This embodiment provides a deep ultraviolet microscope optical system with large numerical aperture and long working distance, the system includes the module provided in embodiment 1, and an image plane and an object plane coaxially arranged with the module.

[0096] Embodiment 10: This embodiment provides a method for designing a deep ultraviolet microscope optical module with a large numerical aperture and a long working distance, which is used to design the module provided in embodiment 1, including:

[0097] Steps for collecting design parameters of the microscope optical system;

[0098] The step of generating an initial configuration of the optical system according to the design parameters of the microscopic optical system;

[0099] Based on the initial parameters of the initial configuration of the optical system, the step of obtaining the focal length and the radius of curvature of each lens group by an optical simulation algorithm;

[0100] The step of outputting the focal length and curvature radius of each lens group in an editable file format.

[0101] Specifically, the layout is:

[0102] Step 1: Overall construction and component arrangement of the optical system

[0103] The object plane constructs the overall framework of the microscopic optical system and clarifies the relative positions and functional relationships of each part. Detailed description: The microscopic optical system arranges the following components in sequence along the optical axis:

[0104] Image plane: It is the imaging output end of the system, used to receive and record the image information after the optical system focuses.

[0105] Tube lens optical system I: includes the first lens group A and the second lens group B, which are used to preliminarily adjust the optical path, control the magnification, and achieve collimation of the optical path.

[0106] Objective optical system II: includes the third lens group C, the fourth lens group D, the fifth lens group E and the sixth internal reflection lens group F, which are used to further adjust the light beam, optimize aberrations and achieve precise focusing at high numerical aperture.

[0107] Object plane: Serves as the optical input of the system and receives reflected or transmitted light from the sample.

[0108] Output of the first step: The component composition and overall layout of the microscope optical system are clarified, laying the foundation for subsequent optical design and optimization.

[0109] Step 2: Design of the tube lens optical system

[0110] The object plane optimizes the design parameters of the tube lens optical system to achieve preliminary adjustment of magnification and optical path.

[0111] Detailed description:

[0112] The tube lens optical system I consists of the following parts:

[0113] The first lens group A is designed as a zoom group, which is used to adjust the magnification of the system while ensuring the stability of optical performance.

[0114] The second lens group B: as an optical path collimating unit, by adjusting the position and parameters of the second lens group, the initial aberration in the optical path can be corrected to ensure that the light beam has a uniform beam distribution when entering the objective optical system.

[0115] The second step output: complete the initial modulation and collimation of the light beam, creating conditions for further optimization of the objective optical system.

[0116] Step 3: Fine adjustment of the objective optical system

[0117] The multi-group lens structure designed in the object plane optimizes the imaging performance in high numerical aperture and deep ultraviolet bands.

[0118] Detailed description:

[0119] Objective optical system II includes the following parts:

[0120] The third lens group C: The lens group can effectively reduce spherical aberration and chromatic aberration, and improve the imaging quality of the system in the deep ultraviolet band.

[0121] The fourth lens group D is a relay lens group used to balance the distribution of the light beam and further optimize the aberration.

[0122] Fifth lens group E: This lens group optimizes the spatial distribution of the light beam to ensure high-resolution imaging effects.

[0123] The sixth internally reflecting lens group F: As the final focusing unit, this lens group achieves high-precision light beam focusing while further reducing aberrations.

[0124] Output of the third step: The objective optical system achieves the coordinated optimization of high numerical aperture and long working distance, providing ideal optical performance for deep ultraviolet microscopy imaging.

[0125] Step 4: System integration and debugging

[0126] The object plane integrates and tunes the various optical systems to achieve the final imaging performance.

[0127] Detailed description:

[0128] During the integration process, the tube optical system I and the objective optical system II are coaxially arranged along the optical axis, and the position, angle and focal length of the lens group are precisely adjusted to ensure that the system can stably provide high numerical aperture imaging in the deep ultraviolet band. Through experimental verification, the parameters of each lens group are optimized to achieve the following performance:

[0129] The numerical aperture of the system remains high to meet high resolution requirements.

[0130] At longer working distances, the system is able to maintain low aberration and high imaging quality.

[0131] Final output: A complete microscope optical system that can achieve high resolution, low aberration and stable imaging performance in the deep ultraviolet band and meet the application requirements of long working distance.

[0132] Implementation Method XI: Combination Figure 1-11 This embodiment is described in detail by using specific examples to further describe the technical solution provided above. Specifically:

[0133] The microscope optical system is coaxially arranged in sequence by an image plane, a tube lens optical system, an objective lens optical system and an object plane;

[0134] The tube lens optical system comprises a first lens group A and a second lens group B;

[0135] The objective optical system comprises a third lens group C, a fourth lens group D, a fifth lens group E and a sixth internal reflection lens group F;

[0136] The first lens group A, the second lens group B, the third lens group C, the fourth lens group D, the fifth lens group E and the sixth internally reflective lens group F are coaxially arranged in sequence;

[0137] The first lens group A is a zoom group;

[0138] 0 <f A / f<30;-30 <f B / f<0;180 <f C / f<210;-10 <f D / f<20;-30 <f E / f<0;-20 <f F / f<10;

[0139] Where, f is the focal length of the entire microscope optical system, f A is the focal length of the first internal reflective lens group A, f B is the focal length of the second lens group B, f C is the focal length of the third lens group C, f D is the focal length of the fourth lens group D, f E is the focal length of the fifth lens group E, f F is the focal length of the sixth internal reflection lens group F.

[0140] In the prior art, since the tube lenses of existing microscope optical systems are mostly of constant magnification, it is not only difficult to meet the user's needs for multiple magnifications and multiple fields of view, but also difficult to match microscope objective lenses with high numerical apertures.

[0141] In this embodiment, if Figure 1 As shown, the image plane, the tube lens optical system, the objective lens optical system and the object plane are coaxially arranged in sequence on the same plane;

[0142] The tube lens optical system is composed of a first lens group A and a second lens group B;

[0143] The objective optical system consists of a third lens group C, a fourth lens group D, a fifth lens group E and a sixth internal reflection lens group F;

[0144] Among them, the first lens group A is a zoom group. When the first lens group A moves along the axial direction, the magnification of the microscope optical system changes accordingly, and the range of change is 50 times to 250 times. The zoom stroke is short and the curve is smooth.

[0145] The ratio of the focal length of the second lens group B to the focal length of the entire microscope optical system is set to be greater than -30 and less than 0;

[0146] The ratio of the focal length of the third lens group C to the focal length of the entire microscope optical system is set to be greater than 180 and less than 210, so as to ensure that the emitted light is parallel light;

[0147] The ratio of the focal length of the fourth lens group D to the focal length of the entire microscope optical system is set to be greater than -10 and less than 20, so as to provide a larger focal power and deflect light;

[0148] The ratio of the focal length of the fifth lens group E to the focal length of the entire microscope optical system is set to be greater than -30 and less than 0, so as to provide a larger focal power and deflect light;

[0149] The ratio of the focal length of the sixth internal reflective lens group F to the focal length of the entire microscope optical system is set to be greater than -20 and less than 10, so as to eliminate the chromatic aberration introduced by the wide spectrum;

[0150] Therefore, the magnification of the tube lens optical system described in this embodiment can achieve multiple magnifications through the axial movement of the first lens group A, which solves the technical problem that the existing tube lenses are mostly of constant magnification, which not only cannot meet the user's needs for multiple magnifications and multiple fields of view, but also cannot match microscope objectives with high numerical apertures.

[0151] The first lens group A includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4 and a fifth lens 5;

[0152] The first lens group A comprises a first lens 1, a second lens 2, a third lens 3, a fourth lens 4 and a fifth lens 5 which are coaxially arranged in sequence;

[0153] The image side surface of the first lens 1 is convex, and the object side surface is convex;

[0154] The image side surface of the second lens 2 is concave, and the object side surface is convex;

[0155] The image side surface of the third lens 3 is a concave surface, and the object side surface is a concave surface;

[0156] The image side surface of the fourth lens 4 is convex, and the object side surface is convex;

[0157] The image side surface of the fifth lens 5 is concave, and the object side surface is convex;

[0158] The optical power of the second lens 2 and the fourth lens 4 are both positive;

[0159] The optical power of the first lens 1, the third lens 3 and the fifth lens 5 are all negative;

[0160] -25mm <f1<-5mm;90mm<f2<110mm;-140mm<f3<-120mm;130mm<f4<150mm;-160mm<f5<-140mm;

[0161] Among them, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens.

[0162] like Figure 2 As shown, the image side surface S1 of the first lens 1 is convex, and the object side surface is S2 convex, and the range of the curvature radius is -90mm <r1<-80mm、50mm<r2<60mm;

[0163] The image side surface S3 of the second lens 2 is concave, and the object side surface S4 is convex, and the range of its curvature radius is -940mm <r3<-930mm、-50mm<r4<-40mm;

[0164] The image side surface S5 of the third lens 3 is concave, and the object side surface is concave S6, and the range of the curvature radius is -60mm <r5<-50mm、70mm<r6<80mm;

[0165] The image side surface S7 of the fourth lens 4 is convex, and the object side surface is convex S8, and the range of the curvature radius is 50mm. <r7<60mm、-70mm<r8<-60mm;

[0166] The image side surface S9 of the fifth lens 5 is concave, and the object side surface S10 is convex, and the range of the curvature radius is -70mm <r9<-60mm、-230mm<r 10 <-220mm;

[0167] The image plane is 430 mm to 2468 mm away from the first lens 1, the first lens 1 is 1 mm to 2 mm away from the second lens 2, the second lens 2 is 1 mm to 2 mm away from the third lens 3, the third lens 3 is 3 mm to 4 mm away from the fourth lens 4, the fourth lens 4 is 0.1 mm to 0.5 mm away from the fifth lens 5, and the fifth lens 5 is 150 mm to 65 mm away from the sixth lens 6, so that the first lens group A is a variable magnification group.

[0168] The focal length of the first lens 1 is set to be greater than -25 mm and less than -5 mm;

[0169] The focal length of the second lens 2 is set to be greater than 90 mm and less than 110 mm;

[0170] The focal length of the third lens 3 is set to be greater than -140 mm and less than -120 mm;

[0171] The focal length of the fourth lens 4 is set to be greater than 130 mm and less than 150 mm;

[0172] The focal length of the fifth lens 5 is set to be larger than -160 mm and smaller than -140 mm.

[0173] The second lens group B includes a sixth lens 6, a seventh lens 7 and an eighth lens 8;

[0174] The image side surface of the sixth lens 6 is concave, and the object side surface is convex;

[0175] The image side surface of the seventh lens 7 is convex, and the object side surface is concave;

[0176] The image side surface of the eighth lens 8 is convex, and the object side surface is convex;

[0177] The refractive powers of the sixth lens 6 and the eighth lens 8 are both positive;

[0178] The seventh lens has a negative optical power;

[0179] 250mm <f6<270mm;-170mm<f7<-150mm;210mm<f8<230mm;

[0180] Among them, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

[0181] In this embodiment, the sixth lens 6, the seventh lens 7 and the eighth lens 8 in the second lens group B are coaxially arranged in sequence on the same plane;

[0182] like Figure 2As shown, the image side surface S11 of the sixth lens 6 is a concave surface, and the object side surface S12 is a convex surface, and the range of the curvature radius is -100 mm. <r 11 <-90mm, -70mm <r 12 <-60mm;

[0183] The image side surface S13 of the seventh lens 7 is convex, and the object side surface S14 is concave, and the range of the curvature radius is 190 mm. <r 13 <200mm、50mm <r 14 <60mm;

[0184] The image side surface S15 of the eighth lens 8 is convex, and the object side surface S16 is concave, and the range of the curvature radius is 190 mm. <r 15 <200mm、50mm <r 16 <60mm;

[0185] The sixth lens 6 and the seventh lens 7 are 6 mm to 8 mm apart, the seventh lens 7 and the eighth lens 8 are 1 mm to 2 mm apart, and the eighth lens 8 and the ninth lens 9 are 90 mm to 100 mm apart;

[0186] The focal length of the sixth lens 6 is set to be greater than 250 mm and less than 270 mm;

[0187] The focal length of the seventh lens 7 is set to be greater than -170 mm and less than -150 mm;

[0188] The focal length of the eighth lens 8 is set to be greater than 210 mm and less than 230 mm;

[0189] The second lens group B can effectively reduce the spherical aberration of the microscope optical system.

[0190] The third lens group C includes a ninth lens 9, a tenth lens 10 and an eleventh lens 11;

[0191] The ninth lens 9, the tenth lens 10 and the eleventh lens 11 are coaxially arranged in sequence;

[0192] The image side surface of the ninth lens 9 is convex, and the object side surface is concave;

[0193] The image side surface of the tenth lens 10 is a concave surface, and the object side surface is a convex surface;

[0194] The image side surface of the eleventh lens 11 is convex, and the object side surface is convex;

[0195] The ninth lens 9 and the eleventh lens 11 have positive refractive powers;

[0196] The tenth lens 10 has a negative optical power;

[0197] 60mm <f9<80mm;-70mm<f 10 <-50mm; 130mm <f 11 <150mm;

[0198] Among them, f9 is the focal length of the ninth lens, f 10 is the focal length of the tenth lens, f 11 is the focal length of the eleventh lens;

[0199] like Figure 2 As shown, the image side surface S17 of the ninth lens 9 is a convex surface, and the object side surface S18 is a convex surface, and the range of the curvature radius is 30 mm. <r 17 <40mm, 15mm <r 18 <25mm;

[0200] The image side surface S19 of the tenth lens 10 is a concave surface, and the object side surface S20 is a convex surface, and the range of the curvature radius is -30 mm. <r 19 <-20mm, -60mm <r 20 <-50mm;

[0201] The image side surface S21 of the eleventh lens 11 is a convex surface, and the object side surface S22 is a convex surface, and the range of the curvature radius is 60 mm. <r 21 <70mm, -120mm <r 22 <-110mm;

[0202] The ninth lens 9 and the tenth lens 10 are 1 mm to 10 mm apart, the tenth lens 10 and the eleventh lens 11 are 0 mm to 5 mm apart, and the eleventh lens 11 and the twelfth lens 12 are 1 mm to 10 mm apart;

[0203] The focal length of the ninth lens 9 is set to be greater than 60 mm and less than 80 mm;

[0204] The focal length of the tenth lens 10 is set to be greater than -70 mm and less than -50 mm;

[0205] The focal length of the eleventh lens 11 is set to be greater than 130 mm and less than 150 mm;

[0206] The third lens group C can ensure that the emitted light is parallel light, thereby reducing the spherical aberration of the microscope optical system.

[0207] The fourth lens group D includes a twelfth lens 12 and a thirteenth lens 13;

[0208] The image side surface of the twelfth lens 12 is convex, and the object side surface is convex;

[0209] The image side surface of the thirteenth lens 13 is a concave surface, and the object side surface is a convex surface;

[0210] The optical power of the twelfth lens 12 is positive;

[0211] The refractive power of the thirteenth lens 13 is negative;

[0212] 40mm <f 12 <60mm; -120mm <f 13 <-100mm;

[0213] Among them, f 12 is the focal length of the twelfth lens, f 13 is the focal length of the thirteenth lens;

[0214] In this embodiment, the twelfth lens 12 and the thirteenth lens 13 in the fourth lens group D are coaxially arranged on the same plane in sequence;

[0215] like Figure 2 As shown, the image side surface S23 of the twelfth lens 12 is a convex surface, and the object side surface S24 is a convex surface, and the range of the curvature radius is 10 mm. <r 23 <20mm, -300mm <r 24 <-290mm;

[0216] The image side surface S25 of the thirteenth lens 13 is a concave surface, and the object side surface S26 is a convex surface, and the range of the curvature radius is -60 mm. <r 25 <-50mm, -130mm <r 26 <-120mm;

[0217] The distance between the twelfth lens 12 and the thirteenth lens 13 is 1 mm to 4 mm, and the distance between the thirteenth lens 13 and the fourteenth lens 14 is 1 mm to 5 mm;

[0218] The focal length of the twelfth lens 12 is set to be greater than 40 mm and less than 60 mm;

[0219] The focal length of the thirteenth lens 13 is set to be greater than -120 mm and less than -100 mm;

[0220] The twelfth lens 12 and the thirteenth lens 13 in the fourth lens group D have relatively large positive refractive power, and can reduce the aperture of light.

[0221] The fifth lens group E includes a fourteenth lens 14, a fifteenth lens 15, a sixteenth lens 16, a seventeenth lens 17 and an eighteenth lens 18;

[0222] The fourteenth lens 14, the fifteenth lens 15, the sixteenth lens 16, the seventeenth lens 17 and the eighteenth lens 18 are coaxially arranged in sequence;

[0223] The image side surface of the fourteenth lens 14 is convex, and the object side surface is convex;

[0224] The image side surface of the fifteenth lens 15 is a concave surface, and the object side surface is a concave surface;

[0225] The image side surface of the sixteenth lens 16 is convex, and the object side surface is convex;

[0226] The image side surface of the seventeenth lens 17 is convex, and the object side surface is concave;

[0227] The image side surface of the eighteenth lens 18 is convex, and the object side surface is convex;

[0228] The optical power of the fourteenth lens 14, the sixteenth lens 16, the seventeenth lens 17 and the eighteenth lens 18 are all positive;

[0229] The refractive power of the fifteenth lens 15 is negative;

[0230] 20mm <f 14 <40mm; -50mm <f 15 <-30mm; 10mm <f 16 <30mm; 70mm <f 17 <90mm; 0mm <f 18 <20mm;

[0231] Among them, f 14 is the focal length of the fourteenth lens, f 15 is the focal length of the sixteenth lens, f 16 is the focal length of the sixteenth lens, f 17 is the focal length of the seventeenth lens, f 18 is the focal length of the eighteenth lens.

[0232] In this embodiment, the fourteenth lens 14, the fifteenth lens 15, the sixteenth lens 16, the seventeenth lens 17 and the eighteenth lens 18 in the fifth lens group E are coaxially arranged in sequence on the same plane;

[0233] like Figure 2 As shown, the image side surface S27 of the fourteenth lens 14 is a convex surface, and the object side surface S28 is a convex surface, and the range of the curvature radius is 110 mm. <r 27 <120mm, -40mm <r 28 <-30mm;

[0234] The image side surface S29 of the fifteenth lens 15 is a concave surface, and the object side surface S30 is a concave surface, and the range of the curvature radius is -20 mm. <r 29 <-10mm, 30mm <r 30 <40mm;

[0235] The image side surface S31 of the sixteenth lens 16 is a convex surface, and the object side surface S32 is a convex surface, and the range of the curvature radius is 0 mm. <r 31 <10mm, -40mm <r 32 <-30mm;

[0236] The image side surface S33 of the seventeenth lens 17 is a convex surface, and the object side surface S34 is a concave surface, and the range of the curvature radius is 30 mm. <r 33 <40mm, 1mm <r 34 <10mm;

[0237] The image side surface S35 of the eighteenth lens 18 is a convex surface, and the object side surface S36 is a convex surface, and the range of the curvature radius is 0 mm. <r 35 <10mm, -100mm <r 36 <-90mm;

[0238] The fourteenth lens 14 and the fifteenth lens 15 are 0mm to 1mm apart, the fifteenth lens 15 and the sixteenth lens 16 are 0mm to 0.5mm apart, the sixteenth lens 16 and the seventeenth lens 17 are 0mm to 0.5mm apart, the seventeenth lens 17 and the eighteenth lens 18 are 0mm to 0.5mm apart, and the eighteenth lens 18 and the nineteenth lens 19 are 10mm to 20mm apart;

[0239] The focal length of the fourteenth lens 14 is set to be greater than 20 mm and less than 40 mm;

[0240] The focal length of the fifteenth lens 15 is set to be greater than -50 mm and less than -30 mm;

[0241] The focal length of the sixteenth lens 16 is set to be greater than 10 mm and less than 30 mm;

[0242] The focal length of the seventeenth lens 17 is set to be greater than 70 mm and less than 90 mm;

[0243] The focal length of the eighteenth lens 18 is set to be greater than 0 mm and less than 20 mm;

[0244] The fifth lens group E has a relatively large positive focal power and can reduce the clear aperture.

[0245] The sixth internal reflection lens group F comprises a nineteenth reflection mirror 19, a twentieth lens 20 and a twenty-first internal reflection lens 21;

[0246] The nineteenth reflector 19, the twentieth lens 20 and the twenty-first internal reflector 21 are coaxially arranged in sequence;

[0247] The image side surface of the nineteenth reflector 19 is convex, and the object side surface is concave;

[0248] The image side surface of the twentieth lens 20 is convex, and the object side surface is concave;

[0249] The image side surface of the twenty-first internally reflective lens 21 is a convex surface, and the object side surface is a flat surface;

[0250] The twentieth lens 20 has a positive optical power;

[0251] 150mm <f 20 <170mm;

[0252] Among them, f 20 The focal length of the 20th lens;

[0253] The nineteenth reflector 19, the twentieth lens 20 and the twenty-first internal reflector 21 are coaxially arranged in sequence;

[0254] like Figure 2 As shown, the image side surface of the nineteenth reflecting lens 19 is a convex surface, and the object side surface S37 is a concave surface, and the range of the curvature radius is 50 mm. <r 37 <60mm;

[0255] The image side surface S38 of the twentieth lens 20 is a convex surface, and the object side surface S39 is a concave surface, and the range of the curvature radius is 70 mm. <r 38 <80mm, 50mm <r 39 <60mm;

[0256] The image side surface S40 of the twenty-first internal reflective lens 21 is a convex surface, and the object side surface is a flat surface, and the range of its curvature radius is 450 mm. <r 40 <460mm;

[0257] like Figure 4 As shown, the X region of the object side S37 of the nineteenth reflector 19 is provided with a reflection region, and the Y region of the image side S40 of the twenty-first internal reflection lens 21 is provided with a reflection region, and the light passes through the X and Y regions and is reflected inside the lens.

[0258] The object-side surface S41 of the twenty-first internal reflective lens 21 is a flat surface.

[0259] Therefore, when natural light passes through the folding-reflective structure with an inner reflective surface, the negative lens with positive focal length has opposite optical characteristics. The nineteenth reflector 19 and the twenty-first inner reflective lens 21 form an achromatic lens group to eliminate the axial chromatic aberration introduced by the wide spectrum.

[0260] The nineteenth reflector 19 and the twentieth lens 20 are 5 mm to 10 mm apart;

[0261] The twentieth lens 20 and the twenty-first internally reflective lens 21 are 15 mm to 20 mm apart;

[0262] The twenty-first internal reflective lens 21 is 2.0 mm away from the object plane;

[0263] The deep ultraviolet large numerical aperture long working distance microscopic optical system achieves a long working distance of 2.0 mm by adopting a composite lens design, a non-parallel optical path design and setting a larger numerical aperture. Table 1 shows the optical parameters of the lens:

[0264]

[0265]

[0266] Among them, t1 and t2 are the variable distances of the first lens group A of the tube lens, the range of the variable distance of t1 is 430mm~2468mm, and the range of the variable distance of t2 is 150mm~65mm. Figure 5 As shown, when the first lens group A moves along the axial direction, the overall magnification of the microscope optical system will change, and the range of change is about 50 times to 250 times.

[0267] When t1=2468mm, t2=65mm, the overall magnification of the microscope optical system is 250 times. Figure 6 As shown, the black line is the field curvature of the microscope optical system of the present invention, the abscissa is the field curvature, the unit is micrometer, the ordinate is the object field, the unit is angle, wherein the field curvature performances of 220nm-meridian, 220nm-sagittal, 350nm-meridian, 350nm-sagittal, 500nm-meridian and 500nm-sagittal are far inferior to the field curvature performance of the present invention, and the field curvature aberration of the present invention is basically corrected; Figure 7 As shown, the black line is the axial chromatic aberration of the microscope optical system described in the present invention, the abscissa is the axial chromatic aberration, the ordinate is the normalized radius, and the difference in axial chromatic aberration in the three bands of 220nm, 350nm and 500nm is much smaller than the focal depth of the microscope optical system described in the present invention, meeting the requirement of apochromatism.

[0268] When t1=1320mm, t2=85mm, the overall magnification of the microscope optical system is 150 times. Figure 8 As shown, the black line is the field curvature of the microscope optical system of the present invention, the abscissa is the field curvature, the unit is micrometer, the ordinate is the object field, the unit is angle, wherein the field curvature performances of 220nm-meridian, 220nm-sagittal, 350nm-meridian, 350nm-sagittal, 500nm-meridian and 500nm-sagittal are far inferior to the field curvature performance of the present invention, and the field curvature aberration of the present invention is basically corrected; Fig. 9As shown, the black line is the axial chromatic aberration of the microscope optical system described in the present invention, the abscissa is the axial chromatic aberration, the ordinate is the normalized radius, and the difference in axial chromatic aberration in the three bands of 220nm, 350nm and 500nm is much smaller than the focal depth of the microscope optical system described in the present invention, meeting the requirement of apochromatism.

[0269] When t1=430mm, t2=65mm, the overall magnification of the microscope optical system is 50 times. Fig.10 As shown, the black line is the field curvature of the microscope optical system of the present invention, the abscissa is the field curvature, the unit is micrometer, the ordinate is the object field, the unit is angle, wherein the field curvature performances of 220nm-meridian, 220nm-sagittal, 350nm-meridian, 350nm-sagittal, 500nm-meridian and 500nm-sagittal are far inferior to the field curvature performance of the present invention, and the field curvature aberration of the present invention is basically corrected; Fig.11 As shown, the black line is the axial chromatic aberration of the microscope optical system described in the present invention, the abscissa is the axial chromatic aberration, the ordinate is the normalized radius, and the difference in axial chromatic aberration in the three bands of 220nm, 350nm and 500nm is much smaller than the focal depth of the microscope optical system described in the present invention, meeting the requirement of apochromatism.

[0270] In summary, a deep ultraviolet large numerical aperture and long working distance microscope optical system has a wavelength band of 220nm~500nm, a numerical aperture of 0.7, a focal length of 9.33mm, and a back working distance of 2.0mm. A non-parallel optical path design is adopted in the design process to reduce the use of lenses, which can meet the user's needs for large numerical aperture and deep ultraviolet wide spectrum microscope optics.

[0271] The technical solution provided by the present invention is further described in detail above through several specific implementation modes in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific implementation modes described above are not intended to be used as limitations on the present invention. Any reasonable modification and improvement of the present invention, combination of implementation modes and equivalent substitution within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A deep ultraviolet microscope optical module with large numerical aperture and long working distance, characterized in that: The modules include: A tube lens optical system and an objective lens optical system arranged coaxially; The tube lens optical system includes a first lens group and a second lens group; The objective optical system comprises a third lens group, a fourth lens group, a fifth lens group and a sixth internally reflective lens group; Among them, 0 <f A / f<30;-30 <f B / f<0;180 <f C / f<210;-10 <f D / f<20;-30 <f E / f<0;-20 <f F / f<10; f is the focal length of the entire microscope optical module, f A is the focal length of the first lens group, f B is the focal length of the second lens group, f C is the focal length of the third lens group, f D is the focal length of the fourth lens group, f E is the focal length of the fifth lens group, f F is the focal length of the sixth internally reflective lens group; the first lens group includes five lenses arranged coaxially; satisfy: -25mm <f1 <-5mm;90mm<f2 <110mm;-140mm<f3 <-120mm;130mm<f4 <150mm;-160mm<f5<-140mm; Wherein, f1, f2, f3, f4 and f5 are focal lengths of five lenses respectively; the second lens group includes three lenses arranged coaxially; satisfy: 250mm <f6<270mm;-170mm<f7<-150mm;210mm<f8<230mm; Wherein, f6, f7 and f8 are focal lengths of three lenses respectively; the third lens group comprises three lenses arranged coaxially; satisfy: 60mm<f9<80mm;-70mm<f 10 <-50mm;130mm<f 11 <150mm; Among them, f9, f 10 and f 11 are focal lengths of the three lenses respectively; the fourth lens group includes two lenses arranged coaxially; satisfy: 40mm<f 12 <60mm;-120mm<f 13 <-100mm; Among them, f 12 and f 13 are the focal lengths of the two lenses respectively; the fifth lens group comprises five lenses arranged coaxially; satisfy: 20mm<f 14 <40mm;-50mm<f 15 <-30mm;10mm<f 16 <30mm;70mm<f 17 <90mm;0mm<f 18 <20mm; Among them, f 14 、f 15 、f 16 、f 17 and f 18 are the focal lengths of the five lenses respectively; the sixth internal reflection lens group comprises three lenses arranged coaxially; satisfy: 150mm<f 20 <170mm; Among them, f 20 is the focal length of one of the lenses.

2. A deep ultraviolet large numerical aperture long working distance microscope optical module according to claim 1, characterized in that: The first lens group, the second lens group, the third lens group, the fourth lens group, the fifth lens group and the sixth internal reflection lens group are arranged in sequence.

3. A deep ultraviolet microscope optical system with large numerical aperture and long working distance, characterized in that: The system comprises the module of claim 1, and an image plane and an object plane coaxially arranged with the module.

4. A method for designing a deep ultraviolet microscope optical module with large numerical aperture and long working distance, characterized in that: A module for designing the module according to claim 1, comprising: Steps for collecting design parameters of the microscope optical system; The step of generating an initial configuration of the optical system according to the design parameters of the microscopic optical system; Based on the initial parameters of the initial configuration of the optical system, the step of obtaining the focal length and the radius of curvature of each lens group by an optical simulation algorithm; The step of outputting the focal length and curvature radius of each lens group in an editable file format.

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