Microscope objectives and microscopes

Abstract

Embodiments of the present disclosure provide a microscope objective and a microscope. The microscope objective includes a first lens group, a second lens group, and a third lens group arranged in sequence from the image side to the object side. The first lens group has a negative optical focal length, at least for correcting coma. The first lens group includes a first cemented lens, and the first cemented lens includes a first lens and a second lens that are cemented together. The second lens group has a positive optical focal length, at least for correcting astigmatism, field curvature, and distortion. The second lens group includes a second cemented lens, a third cemented lens, and a fourth cemented lens. The second cemented lens includes a third lens and a fourth lens, the third cemented lens includes a fifth lens and a sixth lens, and the fourth cemented lens includes a seventh lens and an eighth lens. The third lens group has a positive optical focal length, at least for correcting spherical aberration. The third lens group includes a ninth lens, a fifth cemented lens, and a twelfth lens, and the fifth cemented lens includes a tenth lens and an eleventh lens that are cemented together.

Description

Technical Field

[0001] The embodiments of the present disclosure generally relate to the field of optical imaging technology, and more particularly to a microscope objective and a microscope. Background Art

[0002] With the application of compound semiconductor quantity detection and life science fluorescence detection in scenarios such as defect diversity, product type complexity, weak light emission and high detection efficiency, higher requirements are placed on microscope objectives. In order to meet these application requirements of microscope objectives, microscope objectives need to have a longer working distance and a larger field of view. The long working distance not only provides sufficient operating space, but also facilitates the observation of samples with thicker thickness. The large field of view can significantly increase the imaging field of the microscope objective. For samples of fixed area, a larger imaging range means more light flux and fewer detection times, thereby improving the overall detection efficiency. In some conventional microscope objectives, it is difficult to achieve both a long working distance and a large field of view at the same time, which limits the improvement of detection efficiency. Summary of the invention

[0003] An object of the embodiments of the present disclosure is to provide a microscope objective and a microscope to at least partially solve the above-mentioned problems and other potential problems.

[0004] In a first aspect of the present disclosure, a microscope objective lens is provided. The microscope objective lens comprises: a first lens group, a second lens group and a third lens group arranged in sequence along an optical axis from the image side to the object side; the first lens group has a negative optical focal length and is at least used to correct coma, the first lens group comprises a first cemented lens, and the first cemented lens comprises a first lens and a second lens cemented to each other; the second lens group has a positive optical focal length and is at least used to correct astigmatism, field curvature and distortion, the second lens group comprises a second cemented lens, a third cemented lens and a fourth cemented lens arranged in sequence from the image side to the object side, the second cemented lens comprises a third lens and a fourth lens cemented to each other, the third cemented lens comprises a fifth lens and a sixth lens cemented to each other, and the fourth cemented lens comprises a seventh lens and an eighth lens cemented to each other; the third lens group has a positive optical focal length and is at least used to correct spherical aberration, the third lens group comprises a ninth lens, a fifth cemented lens and a twelfth lens arranged in sequence from the image side to the object side, and the fifth cemented lens comprises a tenth lens and an eleventh lens cemented to each other.

[0005] In some embodiments, the first lens group is also used to correct axial chromatic aberration within a predetermined working band, and the second lens group is also used to correct vertical chromatic aberration within a predetermined working band, so that the microscope objective can achieve apochromatic imaging within the predetermined working band, and the predetermined working band includes 385nm-700nm.

[0006] In some embodiments, the refraction angle of light passing through each lens surface in the microscope objective is below 20°, and the angular deviation of the light relative to the optical axis is less than 3°, and the field curvature inside the microscope objective is within the focal depth range to achieve flat-field microscopic imaging.

[0007] In some embodiments, the microscope objective further includes: a pupil surface arranged on the image side of the first lens group along the optical axis, and a distance between the pupil surface and the vertex of the first lens group is in a range of 1 mm to 10 mm.

[0008] In some embodiments, the diameter of the pupil surface is 20 mm.

[0009] In some embodiments, the image side surface and the object side surface of the first lens are concave; the image side surface and the object side surface of the second lens are convex; the image side surface of the third lens is convex, and the object side surface of the third lens is concave; the image side surface and the object side surface of the fourth lens are convex; the image side surface and the object side surface of the fifth lens are convex; the image side surface of the sixth lens is concave, and the object side surface of the sixth lens is convex; the image side surface and the object side surface of the seventh lens are convex; the image side surface and the object side surface of the eighth lens are concave; the image side surface and the object side surface of the ninth lens are convex; the image side surface of the tenth lens is convex, and the object side surface of the tenth lens is concave; the image side surface of the eleventh lens is convex, and the object side surface of the eleventh lens is concave; the image side surface of the twelfth lens is convex, and the object side surface of the twelfth lens is concave.

[0010] In some embodiments, the distance between the object-side surface of the second lens and the image-side surface of the third lens is in the range of 12.0 mm to 17.0 mm; the distance between the object-side surface of the fourth lens and the image-side surface of the fifth lens is in the range of 0.1 mm to 0.5 mm; the distance between the object-side surface of the sixth lens and the image-side surface of the seventh lens is in the range of 1.0 mm to 1.5 mm; the distance between the object-side surface of the eighth lens and the image-side surface of the ninth lens is in the range of 1.0 mm to 1.5 mm; the distance between the object-side surface of the ninth lens and the image-side surface of the tenth lens is in the range of 0.1 mm to 0.5 mm; the distance between the object-side surface of the eleventh lens and the image-side surface of the twelfth lens is in the range of 0.1 mm to 0.5 mm; and the distance between the vertex of the object-side surface of the twelfth lens and the object plane is in the range of 10.0 mm to 20.0 mm.

[0011] In some embodiments, the first lens has negative optical power, and the focal length of the first lens is in the range of -65 mm to -60 mm; the second lens has positive optical power, and the focal length of the second lens is in the range of 65 mm to 70 mm; the third lens has negative optical power, and the focal length of the third lens is in the range of -250 mm to -245 mm; the fourth lens has positive optical power, and the focal length of the fourth lens is in the range of 283 mm to 288 mm; the fifth lens has positive optical power, and the focal length of the fifth lens is in the range of 1850 mm to 1855 mm; the sixth lens has negative optical power, and the focal length of the sixth lens is in the range of -112 mm to -107 mm. The seventh lens has positive power, and the focal length of the seventh lens is in the range of 60 mm to 65 mm; the eighth lens has negative power, and the focal length of the eighth lens is in the range of -92 mm to -87 mm; the ninth lens has positive power, and the focal length of the ninth lens is in the range of 75 mm to 80 mm; the tenth lens has positive power, and the focal length of the tenth lens is in the range of 63 mm to 68 mm; the eleventh lens has negative power, and the focal length of the eleventh lens is in the range of -50 mm to -45 mm; the twelfth lens has negative power, and the focal length of the twelfth lens is in the range of -48 mm to -43 mm.

[0012] In some embodiments, the difference in Abbe numbers between two lenses of any one of the first cemented lens, the second cemented lens, the third cemented lens, the fourth cemented lens, and the fifth cemented lens is in the range of 5 to 65.

[0013] In some embodiments, the focal lengths of the first lens group, the second lens group, and the third lens group satisfy:

[0014] 14.0<|f1 / f|<14.5, 2.2<|f2 / f|<2.7, 2.1<|f3 / f|<2.6;

[0015] Among them, f is the total focal length of the microscope objective, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, and f3 is the focal length of the third lens group.

[0016] In some embodiments, the first lens group has negative spherical aberration, positive coma, positive astigmatism, negative field curvature and negative distortion; the second lens group has negative spherical aberration, negative coma, negative astigmatism, positive field curvature and positive distortion; the third lens group has positive spherical aberration, negative coma, positive astigmatism, negative field curvature and negative distortion.

[0017] In some embodiments, the first lens group has negative vertical chromatic aberration and negative axial chromatic aberration, the second lens group has positive vertical chromatic aberration and positive axial chromatic aberration, and the third lens group has negative vertical chromatic aberration and positive axial chromatic aberration.

[0018] In some embodiments, the material of the first lens is crown glass, the material of the second lens is flint glass, the material of the third lens is flint glass, the material of the fourth lens is crown glass, the material of the fifth lens is crown glass, the material of the sixth lens is flint glass, the material of the seventh lens is flint glass, the material of the eighth lens is flint glass, the material of the ninth lens is crown glass, the material of the tenth lens is flint glass, the material of the eleventh lens is crown glass, and the material of the twelfth lens is crown glass.

[0019] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, and the twelfth lens are standard spherical lenses.

[0020] In a second aspect of the present disclosure, a microscope is provided, comprising the microscope objective according to the first aspect of the present disclosure.

[0021] In an embodiment of the present disclosure, the microscope objective lens includes a first lens group, a second lens group, and a third lens group arranged in sequence along the optical axis from the image side to the object side. The first lens group has negative optical power and is at least used to correct coma. The first lens group includes a first cemented lens, and the first cemented lens includes a first lens and a second lens cemented to each other. The second lens group has positive optical power and is at least used to correct astigmatism, field curvature, and distortion. The second lens group includes a second cemented lens, a third cemented lens, and a fourth cemented lens arranged in sequence from the image side to the object side. The second cemented lens includes a third lens and a fourth lens cemented to each other, the third cemented lens includes a fifth lens and a sixth lens cemented to each other, and the fourth cemented lens includes a seventh lens and an eighth lens cemented to each other. The third lens group has positive optical power and is at least used to correct spherical aberration. The third lens group includes a ninth lens, a fifth cemented lens, and a twelfth lens arranged in sequence from the image side to the object side, and the fifth cemented lens includes a tenth lens and an eleventh lens cemented to each other.

[0022] With this arrangement, the microscope objective adopts a "negative-positive-positive" three-lens group structure. Through the reasonable distribution of optical power, it can provide a long working distance and effective distance while maintaining a long parfocal length. The microscope objective can allow the illumination light path to have sufficient operating space and support high-resolution imaging at a long working distance. In addition, the first lens group is responsible for correcting coma, the second lens group is responsible for correcting astigmatism, field curvature and distortion, and the third lens group is responsible for correcting spherical aberration. The microscope objective can achieve aberration-free imaging within a larger field of view. The microscope objective adopts a combination of double-cemented lenses and single lenses, which not only eliminates chromatic aberration, but also further corrects field curvature, provides a larger system field of view, and controls field curvature within the depth of field. A larger imaging field of view can be obtained within the same acquisition time, reducing the number of image acquisitions, thereby effectively improving the light flux and work efficiency of the microscope objective.

[0023] It should be understood that the content described in this content section is not intended to limit the key features or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, wherein:

[0025] Figure 1 A schematic diagram of the optical structure of a microscope objective lens according to an embodiment of the present disclosure is shown;

[0026] Figure 2 shows a modulation transfer function graph of an embodiment of the present disclosure;

[0027] Figure 3 A field curvature diagram of a microscope objective lens according to an embodiment of the present disclosure is shown;

[0028] Figure 4 shows a distortion diagram of a microscope objective lens according to an embodiment of the present disclosure;

[0029] Figure 5 shows a 0 pupil color focal shift diagram of a microscope objective lens according to an embodiment of the present disclosure;

[0030] Figure 6 shows a 0.707 pupil color focal shift diagram of a microscope objective lens of an embodiment of the present disclosure;

[0031] Figure 7 1 pupil color focal shift diagram of the microscope objective lens of the embodiment of the present disclosure is shown;

[0032] Figure 8 A diagram showing axial chromatic aberration of a microscope objective lens according to an embodiment of the present disclosure;

[0033] Fig. 9 shows an on-axis field wavefront diagram of a microscope objective lens according to an embodiment of the present disclosure;

[0034] Fig.10 The maximum Y-field wavefront diagram of the microscope objective of an embodiment of the present disclosure is shown.

[0035] Description of reference numerals:

[0036] 100, pupil plane; 200, object plane;

[0037] G1, first lens group; G2, second lens group; G3, third lens group;

[0038] C1, first cemented lens; C2, second cemented lens; C3, third cemented lens; C4, fourth cemented lens; C5, fifth cemented lens;

[0039] L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; L5, fifth lens; L6, sixth lens; L7, seventh lens; L8, eighth lens; L9, ninth lens; L10, tenth lens; L11, eleventh lens; L12, twelfth lens. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0041] As used herein, the term "including" and its variations mean open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc. may refer to different or the same objects.

[0042] As mentioned above, in order to adapt to the application requirements of microscope objective lenses, microscope objective lenses need to have a long working distance and a large field of view. Long working distance not only provides sufficient operating space, but also facilitates the observation of samples with thicker thickness. A large field of view can significantly increase the imaging field of the microscope objective lens. For samples of a fixed area, a larger imaging range means more light flux and fewer detection times, thereby improving the overall detection efficiency. In some conventional microscope objective lenses, it is difficult to achieve both a long working distance and a large field of view at the same time, which limits the improvement of detection efficiency.

[0043] Embodiments of the present disclosure provide a microscope objective and a microscope. The microscope objective includes a first lens group, a second lens group, and a third lens group arranged in sequence along the optical axis from the image side to the object side. The first lens group has negative optical power and is at least used to correct coma. The first lens group includes a first cemented lens, and the first cemented lens includes a first lens and a second lens cemented to each other. The second lens group has positive optical power and is at least used to correct astigmatism, field curvature, and distortion. The second lens group includes a second cemented lens, a third cemented lens, and a fourth cemented lens arranged in sequence from the image side to the object side. The second cemented lens includes a third lens and a fourth lens cemented to each other, the third cemented lens includes a fifth lens and a sixth lens cemented to each other, and the fourth cemented lens includes a seventh lens and an eighth lens cemented to each other. The third lens group has positive optical power and is at least used to correct spherical aberration. The third lens group includes a ninth lens, a fifth cemented lens, and a twelfth lens arranged in sequence from the image side to the object side, and the fifth cemented lens includes a tenth lens and an eleventh lens cemented to each other.

[0044] In this way, the microscope objective adopts a "negative-positive-positive" three-lens group structure, which can provide a longer working distance and effective distance while maintaining a longer parfocal length through the reasonable distribution of optical power. The microscope objective can allow the illumination light path to have sufficient maneuverability and support high-resolution imaging at a long working distance, which is suitable for applications that require fine observation and measurement. In addition, the first lens group is responsible for correcting coma, the second lens group is responsible for correcting astigmatism, field curvature and distortion, and the third lens group is responsible for correcting spherical aberration. The microscope objective can achieve aberration-free imaging within a larger field of view. The microscope objective adopts a combination of double-cemented lenses and single lenses, which not only eliminates chromatic aberration, but also further corrects field curvature, provides a larger system field of view, and controls field curvature within the depth of field. A larger imaging field of view can be obtained within the same acquisition time, reducing the number of image acquisitions, thereby effectively improving the light flux and work efficiency of the microscope objective. The following will be combined with Figure 1 To describe the principles of the present disclosure in detail.

[0045] like Figure 1As shown, the microscope objective adopts a "negative-positive-positive" three-lens group structure. From the image side (close to the image sensor or the observer's eyes) to the object side (close to the sample), the first lens group G1, the second lens group G2 and the third lens group G3 are arranged in sequence. In this way, in the microscope objective, a longer working distance and effective operating space can be provided through the reasonable distribution of optical power, and a certain parfocal length is maintained to ensure that the illumination optical path has sufficient operability space and supports high-resolution imaging at a long working distance.

[0046] As an example, microscope objectives can be used in situations where fine observation and measurement are required, such as compound semiconductor testing and fluorescence imaging in life science research.

[0047] like Figure 1 As shown, the first lens group G1 is located closest to the image side, and it has negative optical power, which can be used to correct coma. The first lens group G1 includes a first cemented lens C1. The first cemented lens C1 includes a first lens L1 and a second lens L2 that are cemented to each other. The double cemented lens not only helps to reduce chromatic aberration, but also can effectively control the light path, so that the microscope objective can reduce the influence of coma without affecting the overall magnification. In this way, the clarity of the image edge can be guaranteed, and the resolution of the imaging can be improved.

[0048] The second lens group G2 has positive optical power, which can be used to correct astigmatism, field curvature and distortion. The second lens group G2 includes a second cemented lens C2, a third cemented lens C3 and a fourth cemented lens C4 arranged in sequence from the image side to the object side. The second cemented lens C2 includes a third lens L3 and a fourth lens L4 cemented to each other, the third cemented lens C3 includes a fifth lens L5 and a sixth lens L6 cemented to each other, and the fourth cemented lens C4 includes a seventh lens L7 and an eighth lens L8 cemented to each other. In the second lens group G2, the cemented lens can optimize the chromatic aberration correction capability, and can effectively deal with problems such as astigmatism, field curvature and distortion. In the microscope objective, correcting the field curvature can maintain the consistency and uniformity of image quality within the entire field of view. In addition, the structure of the second lens group G2 can not only maintain high resolution, but also achieve a larger field of view coverage, thereby improving imaging efficiency and reducing the number of acquisitions.

[0049] The third lens group G3 has positive optical power and can correct spherical aberration. The third lens group G3 includes a ninth lens L9, a fifth cemented lens C5 and a twelfth lens L12. The fifth cemented lens C5 includes a tenth lens L10 and an eleventh lens L11 that are cemented to each other. By using a combination of a single lens and a cemented lens, the third lens group G3 can further optimize the optical performance, not only to deal with spherical aberration, but also to eliminate chromatic aberration and correct field curvature. The microscope objective can provide a larger system field of view and control the field curvature within the depth of field. In this way, the microscope objective can obtain a larger imaging field of view within the same acquisition time, which can reduce the number of image acquisitions, thereby effectively improving the light flux and work efficiency of the microscope objective. In addition, the third lens group G3 can also manage light of different wavelengths to ensure image quality consistency in multi-wavelength imaging applications.

[0050] In this way, microscope objectives can provide high-quality, aberration-free, complete imaging over a large field of view, making them suitable for complex application requirements in fields such as compound semiconductor inspection and life science research.

[0051] Specifically, the long working distance of the microscope objective can provide ample space for easy operation and observation of thick samples. As an example, the microscope objective can provide a working distance of 16.928mm and an effective distance of 40mm through a reasonable distribution of optical power, while maintaining a parfocal distance of 95mm.

[0052] Secondly, the microscope objective can provide a large field of view coverage, which can obtain a larger imaging area within the same acquisition time, reduce the number of acquisitions, and improve work efficiency. As an example, the microscope objective can eliminate chromatic aberration and correct field curvature through the combination of a double-cemented lens and a single lens, and has a system field of view of 30mm. The microscope objective can correct the system field curvature to within the depth of field, obtain a larger imaging field of view at the same acquisition time, reduce the number of image acquisitions, and effectively improve the light flux of the microscope objective.

[0053] Furthermore, the microscope objective can correct aberrations. Through reasonable lens combination and optical power distribution, effective correction of coma, astigmatism, field curvature, distortion and spherical aberration can be achieved to ensure image quality and resolution. In addition, the microscope objective uses cemented lenses to eliminate chromatic aberration between different wavelengths of light, improving the applicability of multi-wavelength imaging. The optimized lens configuration increases the system's light flux, allowing clear images to be obtained even in low light conditions.

[0054] In some embodiments, the first lens group G1 is also used to correct axial chromatic aberration within a predetermined working band, and the second lens group G2 is also used to correct vertical axis chromatic aberration within the predetermined working band. As an example, the predetermined working band includes at least a band range of 385nm to 700nm. The first lens group G1 uses negative optical power to reduce the focus difference of light of different wavelengths, and the second lens group G2 optimizes the light path to reduce the color edge effect, ensuring high resolution and color accuracy throughout the band. In this way, without using an aspherical lens, a chromatic aberration correction effect can be achieved within the band range of 385nm to 700nm, so that under the three aperture conditions of 0 pupil, 0.707 pupil, and 1 pupil, the full-band axial chromatic aberration is controlled within 1 / 4 focal depth (2.352μm), which can improve imaging.

[0055] In addition, the microscope objective exhibits smaller aberrations in the near-infrared band greater than 700nm, which can further expand its application range and make it suitable for a variety of precision detection and scientific research tasks.

[0056] In some embodiments, in the microscope objective, the refraction angle of light passing through each lens surface is controlled to be less than 20°, while ensuring that the angle deviation of the light relative to the optical axis is less than 3°. In this way, the change of the light path can be limited and the generation of aberrations can be reduced. In addition, the field curvature inside the microscope objective is accurately corrected within the focal depth range, so that the imaging plane in the entire field of view is close to an ideal flat state, thereby achieving flat-field microscopic imaging.

[0057] In some embodiments, Figure 1 As shown, the microscope objective further includes a pupil plane 100. The pupil plane 100 is arranged on the image side of the first lens group G1 along the optical axis, and the distance between the pupil plane 100 and the vertex of the first lens group G1 is maintained in the range of 1 mm to 10 mm. As an example, the distance between the entrance pupil position and the vertex of the first lens L1 of the first lens group G1 is 8 mm, which is close to the flange surface of the microscope objective. By setting the position of the pupil plane 100 before the vertex of the first lens group G1, a differential interference contrast prism (DIC) can be added in the middle of the optical system so that the coherence plane of the differential interference contrast prism coincides with the pupil plane 100, thereby realizing the DIC imaging function. The differential interference contrast prism can enhance the contrast of sample details, especially for transparent or translucent, unstained samples, providing a pseudo three-dimensional image effect, thereby improving the visibility and resolution of the internal structure of cells and tissues.

[0058] In some embodiments, in the microscope objective, the diameter of the pupil plane 100 is 20 mm. By adopting a front entrance pupil method with an entrance pupil diameter of 20 mm, the microscope objective can achieve high-throughput light transmission with a numerical aperture of 0.25. In this way, under the same field of view conditions, the optical system can obtain a faster exposure time and significantly improve the detection efficiency. Compared with the common 5x microscope objective on the market, the microscope objective of the embodiment of the present disclosure can increase the numerical aperture to 0.25, enhance the light collection capability, and thus achieve more efficient imaging performance and higher resolution.

[0059] In some embodiments, Figure 1 As shown, the image side surface and the object side surface of the first lens L1 are concave surfaces. The image side surface and the object side surface of the second lens L2 are convex surfaces. The image side surface of the third lens L3 is convex, and the object side surface of the third lens L3 is concave. The image side surface and the object side surface of the fourth lens L4 are convex surfaces. The image side surface and the object side surface of the fifth lens L5 are convex surfaces. The image side surface of the sixth lens L6 is concave, and the object side surface of the sixth lens L6 is convex. The image side surface and the object side surface of the seventh lens L7 are convex surfaces. The image side surface and the object side surface of the eighth lens L8 are concave surfaces. The image side surface and the object side surface of the ninth lens L9 are convex surfaces. The image side surface of the tenth lens L10 is convex, and the object side surface of the tenth lens L10 is concave. The image side surface of the eleventh lens L11 is convex, and the object side surface of the eleventh lens L11 is concave. The image side surface of the twelfth lens L12 is convex, and the object side surface of the twelfth lens L12 is concave.

[0060] In this way, the first lens L1 adopts a biconcave structure, and then transitions to multiple biconvex lenses (such as the second lens L2, the fourth lens L4, the fifth lens L5, and the seventh lens L7). Multiple biconvex lenses can converge light, ensure sufficient light flux, and help maintain the high resolution of the system. Between these biconvex lenses, lenses with single-sided convex and single-sided concave surfaces (such as the third lens L3, the sixth lens L6, the tenth lens L10, the eleventh lens L11, and the twelfth lens L12) are inserted accordingly, which can control the light path and help correct various aberrations such as spherical aberration and field curvature while maintaining good chromatic aberration. The biconcave structure of the eighth lens L8 can balance the optical properties of the entire optical system, such as the optical properties of processing marginal light.

[0061] In some embodiments, a distance between the object-side surface of the second lens L2 and the image-side surface of the third lens L3 is in a range of 12.0 mm to 17.0 mm. A distance between the object-side surface of the fourth lens L4 and the image-side surface of the fifth lens L5 is in a range of 0.1 mm to 0.5 mm. A distance between the object-side surface of the sixth lens L6 and the image-side surface of the seventh lens L7 is in a range of 1.0 mm to 1.5 mm. A distance between the object-side surface of the eighth lens L8 and the image-side surface of the ninth lens L9 is in a range of 1.0 mm to 1.5 mm. A distance between the object-side surface of the ninth lens L9 and the image-side surface of the tenth lens L10 is in a range of 0.1 mm to 0.5 mm. A distance between the object-side surface of the eleventh lens L11 and the image-side surface of the twelfth lens L12 is in a range of 0.1 mm to 0.5 mm. A distance between the vertex of the object-side surface of the twelfth lens L12 and the object plane 200 is in a range of 10.0 mm to 20.0 mm. With this arrangement, by adjusting the distance between lenses, the microscope objective can not only optimize the light path and reduce aberrations, but also make the optical system more compact and efficient.

[0062] In some embodiments, the first lens L1 has negative power, and the focal length of the first lens L1 is in the range of -65 mm to -60 mm. The second lens L2 has positive power, and the focal length of the second lens L2 is in the range of 65 mm to 70 mm. The third lens L3 has negative power, and the focal length of the third lens L3 is in the range of -250 mm to -245 mm. The fourth lens L4 has positive power, and the focal length of the fourth lens L4 is in the range of 283 mm to 288 mm. The fifth lens L5 has positive power, and the focal length of the fifth lens L5 is in the range of 1850 mm to 1855 mm. The sixth lens L6 has negative power, and the focal length of the sixth lens L6 is in the range of -112 mm to -107 mm. The seventh lens L7 has positive power, and the focal length of the seventh lens L7 is in the range of 60 mm to 65 mm. The eighth lens L8 has negative power, and the focal length of the eighth lens L8 is in the range of -92 mm to -87 mm. The ninth lens L9 has positive power, and the focal length of the ninth lens L9 is in the range of 75 mm to 80 mm. The tenth lens L10 has positive power, and the focal length of the tenth lens L10 is in the range of 63 mm to 68 mm. The eleventh lens L11 has negative power, and the focal length of the eleventh lens L11 is in the range of -50 mm to -45 mm. The twelfth lens L12 has negative power, and the focal length of the twelfth lens L12 is in the range of -48 mm to -43 mm.

[0063] In this way, negative and positive power lenses complement each other, maintaining the total magnification of the system while reducing common aberrations such as coma, spherical aberration, astigmatism, and chromatic aberration. In addition, microscope objectives use a combination of lenses with different focal lengths to optimize the light path. Short focal length negative power lenses can adjust the light at close ranges, while long focal length positive power lenses are responsible for converging light at long distances. In this way, the optical system can provide high-quality imaging effects over a wide range of wavelengths.

[0064] In some embodiments, the difference in Abbe number between two constituent lenses of any one of the first cemented lens C1, the second cemented lens C2, the third cemented lens C3, the fourth cemented lens C4, and the fifth cemented lens C5 is in the range of 5 to 65. In this way, a larger difference in Abbe number helps correct chromatic aberration, ensuring that light of different wavelengths can converge at the same focal point, thereby improving imaging quality. Without introducing complex components, an excellent chromatic aberration correction effect can be achieved, ensuring high resolution and color accuracy in the visible to near-infrared band.

[0065] In some embodiments, the focal lengths of the first lens group G1, the second lens group G2, and the third lens group G3 satisfy:

[0066] 14.0<|f1 / f|<14.5, 2.2<|f2 / f|<2.7, 2.1<|f3 / f|<2.6;

[0067] Among them, f is the total focal length of the microscope objective lens, f1 is the focal length of the first lens group G1, f2 is the focal length of the second lens group G2, and f3 is the focal length of the third lens group G3.

[0068] In some embodiments, the first lens group G1 has negative spherical aberration, positive coma, positive astigmatism, negative field curvature and negative distortion, which can provide a preliminary basis for aberration correction for subsequent lens groups. The second lens group G2 has negative spherical aberration, negative coma, negative astigmatism, positive field curvature and positive distortion, which can offset some aberrations in the first lens group G1 and further optimize the light path. The third lens group G3 has positive spherical aberration, negative coma, positive astigmatism, negative field curvature and negative distortion, which can continue to correct the residual aberrations of the first two groups. In this way, the aberrations between the lens groups offset and complement each other, so that the microscope objective can provide high resolution and flat imaging effects in the entire working band.

[0069] In some embodiments, the first lens group G1 has negative vertical axis chromatic aberration and negative axial chromatic aberration, the second lens group G2 has positive vertical axis chromatic aberration and positive axial chromatic aberration, and the third lens group G3 has negative vertical axis chromatic aberration and positive axial chromatic aberration. In this complementary manner, the chromatic aberrations between the lens groups offset and complement each other, so that the microscope objective lens can provide high-resolution, aberration-free and perfect imaging effects in the entire working band.

[0070] In some embodiments, the material of the first lens L1 is crown glass, the material of the second lens L2 is flint glass, the material of the third lens L3 is flint glass, the material of the fourth lens L4 is crown glass, the material of the fifth lens L5 is crown glass, the material of the sixth lens L6 is flint glass, the material of the seventh lens L7 is flint glass, the material of the eighth lens L8 is flint glass, the material of the ninth lens L9 is crown glass, the material of the tenth lens L10 is flint glass, the material of the eleventh lens L11 is crown glass, and the material of the twelfth lens L12 is crown glass. In this way, by applying the crown glass and flint glass combination to each lens, the microscope objective can achieve chromatic aberration correction, and can also perform light management and aberration control.

[0071] In some embodiments, 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, the ninth lens L9, the tenth lens L10, the eleventh lens L11 and the twelfth lens L12 are standard spherical lenses. In this way, the manufacturing process of standard spherical lenses is mature, which can ensure high quality and consistency, and can reduce manufacturing costs. In addition, spherical lenses can provide excellent light convergence capabilities, maintain high resolution and contrast, and ensure image clarity and detail performance. Through the combination of spherical lenses and material selection, aberration problems such as chromatic aberration and spherical aberration can be effectively corrected, thereby improving imaging quality.

[0072] In a second aspect of the present disclosure, a microscope is provided. The microscope includes any one of the above-mentioned microscope objective lenses. In the microscope objective lens of the microscope, a "negative-positive-positive" three-lens group structure is adopted, and through the reasonable distribution of optical power, a longer working distance and effective distance can be provided, while maintaining a longer parfocal length. The microscope objective lens can make the illumination light path have enough operability space and support high-resolution imaging at a long working distance, which is suitable for applications requiring fine observation and measurement. In addition, the first lens group G1 is responsible for correcting coma, the second lens group G2 is responsible for correcting astigmatism, field curvature and distortion, and the third lens group G3 is responsible for correcting spherical aberration. The microscope objective lens can achieve perfect imaging without aberration within a larger field of view. The microscope objective lens adopts a combination of double-cemented lenses and single lenses, which not only eliminates chromatic aberration, but also further corrects field curvature, provides a larger system field of view number, and controls field curvature within the depth of field. A larger imaging field of view can be obtained within the same acquisition time, reducing the number of image acquisitions, thereby effectively improving the luminous flux and work efficiency of the microscope objective lens.

[0073] The following uses the optical parameter values ​​shown in Table 1 and Figures 2 to 10 The experimental data are exemplified to describe the principle of the present disclosure in detail.

[0074] Table 1:

[0075]

[0076] S1 refers to the surface of the aperture at the pupil plane;

[0077] S2 refers to the image side surface of the first prism L1;

[0078] S3 refers to the object side surface of the first prism L1;

[0079] S4 refers to the object side surface of the second prism L2;

[0080] S5 refers to the image side surface of the third prism L3;

[0081] S6 refers to the object side surface of the third prism L3;

[0082] S7 refers to the object side surface of the fourth prism L4;

[0083] S8 refers to the image side surface of the fifth prism L5;

[0084] S9 refers to the object side surface of the fifth prism L5;

[0085] S10 refers to the object side surface of the sixth prism L6;

[0086] S11 refers to the image side surface of the seventh prism L7;

[0087] S12 refers to the object side surface of the seventh prism L7;

[0088] S13 refers to the object side surface of the eighth prism L8;

[0089] S14 refers to the image side surface of the ninth prism L9;

[0090] S15 refers to the object side surface of the ninth prism L9;

[0091] S16 refers to the image side surface of the tenth prism L10;

[0092] S17 refers to the object side surface of the tenth prism L10;

[0093] S18 refers to the object side surface of the eleventh prism L11;

[0094] S19 refers to the image side surface of the twelfth prism L12;

[0095] S20 refers to the object-side surface of the twelfth prism L12.

[0096] In the embodiment of the present disclosure, the working distance is 16.928 mm, the numerical aperture is 0.25, the field of view is 30 mm, the working band is 385 nm to 700 nm, the parfocal distance is 95 mm, the effective focal length is 40 mm, and the overall magnification is 5 times when used with a tube lens with a focal length of 200 mm.

[0097] In the embodiment of the present disclosure, the focal depth δ of the optical system of the microscope objective is 9.408um, and the depth of field σ obj It is 4.704um and the resolution σ is 1.43um.

[0098] Figure 2 : is a full-field full-band modulation transfer function curve diagram of the embodiment of the present disclosure, the horizontal axis is the spatial frequency, the unit is lp / mm; the vertical axis is the modulus of the optical transfer function. Figure 2 As shown, the modulation transfer function curve of the embodiment of the present disclosure is close to the diffraction limit, and the optical transfer function modulus is greater than 0.28 at 500lp / mm, and the imaging quality is good.

[0099] Figure 3 : is a field curvature diagram of an embodiment of the present disclosure, the horizontal axis is the defocus amount, the unit is micrometer; the vertical axis is the field angle, the unit is degree. Figure 3 As shown, the meridional field curvature value of the embodiment of the present disclosure is slightly larger than the sagittal field curvature. The meridional field curvature is 4.2um, which is within the depth of field 4.704um and smaller than the focal depth 9.408um. It is a flat-field objective lens.

[0100] Figure 4 : is a distortion diagram of an embodiment of the present disclosure, the horizontal axis is the distortion percentage, the unit is %; the vertical axis is the field of view, the unit is degree. Figure 4As shown, the maximum distortion of the embodiment of the present disclosure is about 0.2%, the distortion amount is small, and the distortion is effectively corrected.

[0101] Figure 5 : is a color focus shift diagram of the zero pupil full band of the embodiment of the present disclosure, the horizontal axis is the focus shift amount, the unit is micrometer; the vertical axis is the wavelength, the unit is micrometer. Figure 5 As shown, the maximum focal shift change of the 0 pupil in the embodiment of the present disclosure is 2.3390 um, and within the 1 / 4 focal depth of 2.352 um, the 0 pupil can achieve perfect imaging.

[0102] Figure 6 0.707 pupil full band color focus shift diagram of the embodiment of the present disclosure, the horizontal axis is the focus shift amount, the unit is micron; the vertical axis is the wavelength, the unit is micron. Figure 6 As shown, the maximum focal shift variation of the 0.707 pupil in the embodiment of the present disclosure is 1.8850 um. Within the 1 / 4 focal depth of 2.352 um, the 0.707 pupil can achieve perfect imaging.

[0103] Figure 7 : is a color focus shift diagram of a pupil in the full band of an embodiment of the present disclosure, the horizontal axis is the focus shift amount, in micrometers; the vertical axis is the wavelength, in micrometers. Figure 7 As shown, the maximum focal shift variation of one pupil in the embodiment of the present disclosure is 2.3174um, and within the 1 / 4 focal depth of 2.352um, one pupil can achieve perfect imaging.

[0104] Figure 8 : is a full-field axial chromatic aberration curve diagram of an embodiment of the present disclosure, the horizontal axis is the axial chromatic aberration change, in micrometers; the vertical axis is the normalized pupil coordinate. Figure 8 As shown, axial chromatic aberration is well corrected and is an apochromatic objective.

[0105] Fig. 9 is an on-axis field of view wavefront diagram of an embodiment of the present disclosure, such as Fig. 9 As shown, the peak-to-valley value (PV value) of the on-axis field of view of the embodiment of the present disclosure is 0.1278λ, and the root mean square value (RMS) is 0.0461λ.

[0106] Fig.10 is the maximum Y field of view wavefront diagram of the embodiment of the present disclosure, Fig.10 As shown, the peak-to-valley value of the maximum Y field of view of the embodiment of the present disclosure is 0.3277λ, and the root mean square value is 0.081λ.

[0107] It can be seen from this that the embodiments of the present disclosure can provide a long working distance, high numerical aperture, large field of view, wide band, plan-field apochromat, 5x microscope objective lens, which has an ultra-long working distance of more than 16 mm, a high numerical aperture of 0.25, a field of view number of 30 mm, and a wide band of 385 nm to 700 nm. While improving the objective lens detection light flux, it can also achieve plan-field apochromat correction with low field curvature, low distortion, and low axial chromatic aberration.

[0108] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A microscope objective lens, characterized in that: include: A first lens group (G1), a second lens group (G2) and a third lens group (G3) are arranged in sequence along the optical axis from the image side to the object side, wherein the focal lengths of the first lens group (G1), the second lens group (G2) and the third lens group (G3) satisfy: 14.0<|f1 / f|<14.5, 2.2<|f2 / f|<2.7, 2.1<|f3 / f|<2.6; wherein f is the total focal length of the microscope objective, f1 is the focal length of the first lens group (G1), f2 is the focal length of the second lens group (G2), f3 is the focal length of the third lens group (G3), and the number of lenses having optical power in the microscope objective is 12; The first lens group (G1) has negative optical power and is used at least to correct coma, and the first lens group (G1) includes a first cemented lens (C1), and the first cemented lens (C1) includes a first lens (L1) and a second lens (L2) cemented to each other; The second lens group (G2) has positive optical power and is at least used to correct astigmatism, field curvature and distortion. The second lens group (G2) includes a second cemented lens (C2), a third cemented lens (C3) and a fourth cemented lens (C4) arranged in sequence from the image side to the object side. The second cemented lens (C2) includes a third lens (L3) and a fourth lens (L4) cemented to each other. The third cemented lens (C3) includes a fifth lens (L5) and a sixth lens (L6) cemented to each other. The fourth cemented lens (C4) includes a seventh lens (L7) and an eighth lens (L8) cemented to each other. The third lens group (G3) has positive refractive power and is used at least to correct spherical aberration. The third lens group (G3) includes a ninth lens (L9), a fifth cemented lens (C5) and a twelfth lens (L12) arranged in sequence from the image side to the object side. The fifth cemented lens (C5) includes a tenth lens (L10) and an eleventh lens (L11) cemented to each other. The first lens (L1) has negative focal power, the second lens (L2) has positive focal power, the third lens (L3) has negative focal power, the fourth lens (L4) has positive focal power, the fifth lens (L5) has positive focal power, the sixth lens (L6) has negative focal power, the seventh lens (L7) has positive focal power, the eighth lens (L8) has negative focal power, the ninth lens (L9) has positive focal power, the tenth lens (L10) has positive focal power, the eleventh lens (L11) has negative focal power, and the twelfth lens (L12) has negative focal power.

2. The microscope objective lens according to claim 1, wherein the first lens group (G1) is also used to correct axial chromatic aberration within a predetermined working band, and the second lens group (G2) is also used to correct vertical chromatic aberration within the predetermined working band, so that the microscope objective lens can achieve apochromatic imaging within the predetermined working band, and the predetermined working band includes 385nm-700nm.

3. The microscope objective lens according to claim 1, wherein the refraction angle of the light passing through each lens surface in the microscope objective lens is less than 20°, and the angular deviation of the light relative to the optical axis is less than 3°, and the field curvature inside the microscope objective lens is within the focal depth range to achieve flat-field microscopic imaging.

4. The microscope objective lens according to claim 1, further comprising: A pupil surface (100) is arranged on the image side of the first lens group (G1) along the optical axis, and a distance between the pupil surface (100) and the vertex of the first lens group (G1) is in a range of 1 mm to 10 mm.

5. The microscope objective according to claim 4, wherein the diameter of the pupil surface (100) is 20 mm.

6. The microscope objective according to any one of claims 1 to 5, wherein the image-side surface and the object-side surface of the first lens (L1) are concave surfaces; The image side surface and the object side surface of the second lens (L2) are convex surfaces; The image side surface of the third lens (L3) is a convex surface, and the object side surface of the third lens (L3) is a concave surface; The image-side surface and the object-side surface of the fourth lens (L4) are convex surfaces; The image-side surface and the object-side surface of the fifth lens (L5) are convex surfaces; The image side surface of the sixth lens (L6) is a concave surface, and the object side surface of the sixth lens (L6) is a convex surface; The image-side surface and the object-side surface of the seventh lens (L7) are convex surfaces; The image-side surface and the object-side surface of the eighth lens (L8) are concave surfaces; The image side surface and the object side surface of the ninth lens (L9) are convex surfaces; The image side surface of the tenth lens (L10) is a convex surface, and the object side surface of the tenth lens (L10) is a concave surface; The image side surface of the eleventh lens (L11) is a convex surface, and the object side surface of the eleventh lens (L11) is a concave surface; The image side surface of the twelfth lens (L12) is a convex surface, and the object side surface of the twelfth lens (L12) is a concave surface.

7. The microscope objective according to claim 6, wherein the distance between the object side surface of the second lens (L2) and the image side surface of the third lens (L3) is in the range of 12.0 mm to 17.0 mm; The distance between the object side surface of the fourth lens (L4) and the image side surface of the fifth lens (L5) is in the range of 0.1 mm to 0.5 mm; The distance between the object side surface of the sixth lens (L6) and the image side surface of the seventh lens (L7) is in the range of 1.0 mm to 1.5 mm; The distance between the object side surface of the eighth lens (L8) and the image side surface of the ninth lens (L9) is in the range of 1.0 mm to 1.5 mm; The distance between the object side surface of the ninth lens (L9) and the image side surface of the tenth lens (L10) is in the range of 0.1 mm to 0.5 mm; The distance between the object side surface of the eleventh lens (L11) and the image side surface of the twelfth lens (L12) is in the range of 0.1 mm to 0.5 mm; The distance between the vertex of the object-side surface of the twelfth lens (L12) and the object plane (200) is in the range of 10.0 mm to 20.0 mm.

8. The microscope objective according to any one of claims 1 to 5, wherein the focal length of the first lens (L1) is in the range of -65 mm to -60 mm; The focal length of the second lens (L2) is in the range of 65 mm to 70 mm; The focal length of the third lens (L3) is in the range of -250 mm to -245 mm; The focal length of the fourth lens (L4) is in the range of 283 mm to 288 mm; The focal length of the fifth lens (L5) is in the range of 1850 mm to 1855 mm; The focal length of the sixth lens (L6) is in the range of -112 mm to -107 mm; The focal length of the seventh lens (L7) is in the range of 60 mm to 65 mm; The focal length of the eighth lens (L8) is in the range of -92 mm to -87 mm; The focal length of the ninth lens (L9) is in the range of 75 mm to 80 mm; The focal length of the tenth lens (L10) is in the range of 63 mm to 68 mm; The focal length of the eleventh lens (L11) is in the range of -50 mm to -45 mm; The focal length of the twelfth lens (L12) is in the range of -48 mm to -43 mm.

9. The microscope objective according to any one of claims 1 to 5, wherein the difference in Abbe number between two lenses of any one of the first cemented lens (C1), the second cemented lens (C2), the third cemented lens (C3), the fourth cemented lens (C4) and the fifth cemented lens (C5) is in the range of 5 to 65.

10. The microscope objective according to any one of claims 1 to 5, wherein the first lens group (G1) has negative spherical aberration, positive coma, positive astigmatism, negative field curvature and negative distortion; The second lens group (G2) has negative spherical aberration, negative coma, negative astigmatism, positive field curvature and positive distortion; The third lens group (G3) has positive spherical aberration, negative coma, positive astigmatism, negative field curvature and negative distortion.

11. The microscope objective according to any one of claims 1 to 5, wherein the first lens group (G1) has negative vertical axis chromatic aberration and negative axial chromatic aberration, the second lens group (G2) has positive vertical axis chromatic aberration and positive axial chromatic aberration, and the third lens group (G3) has negative vertical axis chromatic aberration and positive axial chromatic aberration.

12. The microscope objective according to any one of claims 1 to 5, wherein the material of the first lens (L1) is crown glass, the material of the second lens (L2) is flint glass, the material of the third lens (L3) is flint glass, the material of the fourth lens (L4) is crown glass, the material of the fifth lens (L5) is crown glass, the material of the sixth lens (L6) is flint glass, the material of the seventh lens (L7) is flint glass, the material of the eighth lens (L8) is flint glass, the material of the ninth lens (L9) is crown glass, the material of the tenth lens (L10) is flint glass, the material of the eleventh lens (L11) is crown glass, and the material of the twelfth lens (L12) is crown glass.

13. The microscope objective according to any one of claims 1 to 5, wherein 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), the ninth lens (L9), the tenth lens (L10), the eleventh lens (L11) and the twelfth lens (L12) are standard spherical lenses.

14. A microscope, characterized in that: include: A microscope objective according to any one of claims 1 to 13.

Images