A wide spectrum ultra-long working distance microscope objective lens and imaging device thereof

Abstract

The present invention relates to a wide-spectrum, ultra-long-working-distance microscope objective lens and an imaging device thereof in the field of optical imaging technology. The microscope objective lens comprises, from the image side to the object side, a first lens group, a second lens group, an aperture, and a third lens group having the same optical axis, and satisfies the following conditions: 1.7≤|f1 / f|≤2.2; 3.4≤|f2 / f|≤3.9; 2.5≤|f3 / f|≤3. f is the total focal length of the microscope objective lens, and f1, f2, and f3 are the focal lengths of the three lens groups, respectively. The first lens group has a negative optical focal length, and comprises, from the image side to the object side, a first lens, which is a meniscus lens with a negative optical focal length, and a second lens, which is a biconcave lens with a negative optical focal length, in sequence along the optical axis. The focal length of the first lens is 40 mm to 30 mm; the focal length of the second lens is 20 mm to 10 mm, and the object side surface of the first lens and the image side surface of the second lens are glued together. The present invention ensures an ultra-long working distance while having a flat field of view, is easy to process and detect, and has excellent imaging quality, thus solving the defect that high-imaging-quality microscope objective lenses in the prior art cannot simultaneously achieve an ultra-long working distance.

Description

Technical Field

[0001] The present invention relates to a microscope objective lens in the field of optical imaging technology, in particular to a microscope objective lens with a wide spectrum and an ultra-long working distance, and an imaging device using the microscope objective lens. Background Art

[0002] As microscopic inspection expands into more diverse application scenarios, higher requirements are placed on the operability of microscope objectives, specifically the need for ultra-long working distances. Ultra-long working distance microscope objectives provide greater space between the microscope and the sample being observed, enabling compatibility with other components of the inspection system and facilitating focusing, thereby reducing the risk of damaging the sample. Therefore, further increasing the working distance of microscope objectives while ensuring image quality, thereby enhancing their operability, is of paramount importance for microscopic inspection.

[0003] The ultra-long working distance objective lens model 378-802-6 from Japan's Mitutoyo M Plan Apo series has a wavelength range of 436-656nm, a magnification of 5x, and a working distance of only 34mm. Another example is the long working distance objective lens model MY5X-822 from the US company Sorebo, which has a wavelength range of 480-1800nm, a magnification of 5x, and a working distance of 37.5mm. Existing products and technologies cannot meet the requirements for observing samples in extreme environments. Summary of the Invention

[0004] The present invention provides a wide-spectrum ultra-long working distance microscope objective lens and an imaging device using the microscope objective lens. The microscope objective lens of the present invention is a wide-spectrum ultra-long working distance microscope objective lens with a numerical aperture of 0.15 and a magnification of 5 times. Its purpose is to solve the defect that the existing microscope objective lens with high imaging quality cannot achieve an ultra-long working distance.

[0005] The present invention is implemented using the following technical solution: a wide-spectrum, ultra-long working distance microscope objective lens, comprising, from the image side to the object side, a first lens group, a second lens group, an aperture, and a third lens group, all having the same optical axis. The microscope objective lens satisfies the following conditions: 1.7 ≤ |f1 / f| ≤ 2.2; 3.4 ≤ |f2 / f| ≤ 3.9; and 2.5 ≤ |f3 / f| ≤ 3. In the formulas, f is the total focal length of the microscope objective lens, and f1, f2, and f3 are the focal lengths of the first, second, and third lens groups, respectively. Among them, the first lens group has negative optical power and includes a first lens and a second lens in sequence from the image side to the object side along the optical axis; the first lens is a meniscus lens with negative optical power, its focal length is -40mm to -30mm, and its image side surface is concave and its object side surface is convex; the second lens is a biconcave lens with negative optical power, its focal length is -20mm to -10mm, its image side surface is concave and its object side surface is concave; the object side surface of the first lens and the image side surface of the second lens are cemented together.

[0006] As a further improvement of the above solution, the first lens group is a doublet lens group; the second lens group is a triplet lens group; and the third lens group includes two doublet lens groups in sequence from the image side to the object side.

[0007] As a further improvement of the above solution, the air gap between the first lens group and the second lens group is within a range of 51.3 to 51.8 mm; the air gap between the second lens group and the third lens group is within a range of 26.9 to 27.4 mm.

[0008] As a further improvement to the above solution, the second lens group has negative optical power and, from the image side to the object side along the optical axis, includes, in order: a third lens element that is a biconcave lens with negative optical power; a fourth lens element that is a biconvex lens with positive optical power; and a fifth lens element that is a biconcave lens with negative optical power. The object-side surface of the third lens element is cemented to the image-side surface of the fourth lens element; and the object-side surface of the fourth lens element is cemented to the image-side surface of the fifth lens element.

[0009] Furthermore, the focal length of the third lens is -30mm to -20mm, the image side surface is concave, and the object side surface is concave; the focal length of the fourth lens is 20mm to 30mm, the image side surface is convex, and the object side surface is convex; the focal length of the fifth lens is -80mm to -70mm, the image side surface is concave, and the object side surface is concave.

[0010] As a further improvement to the above solution, the third lens group has positive optical power and includes, from the image side to the object side along the optical axis, a sixth lens group that is a biconcave lens with negative optical power, a seventh lens group that is a biconvex lens with positive optical power, an eighth lens group that is a biconcave lens with negative optical power, a ninth lens group that is a biconvex lens with positive optical power, a tenth lens group that is a biconvex lens with positive optical power, an eleventh lens group that is a biconvex lens with positive optical power, and a twelfth lens group that is a convex-plano lens with positive optical power. Furthermore, the object-side surface of the sixth lens group is cemented to the image-side surface of the seventh lens group, the object-side surface of the eighth lens group is cemented to the image-side surface of the ninth lens group, and the air gap between the object-side surface of the seventh lens group and the image-side surface of the eighth lens group is within 0.1 to 0.5 mm.

[0011] Furthermore, the focal length of the sixth lens is -60mm to -50mm, the image side surface is concave, and the object side surface is concave; the focal length of the seventh lens is 30mm to 40mm, the image side surface is convex, and the object side surface is convex; the focal length of the eighth lens is -30mm to -20mm, the image side surface is concave, and the object side surface is concave; the focal length of the ninth lens is 70mm to 80mm, the image side surface is convex, and the object side surface is convex; the focal length of the tenth lens is 120mm to 130mm, the image side surface is convex, and the object side surface is convex; the focal length of the eleventh lens is 80mm to 90mm, the image side surface is convex, and the object side surface is convex; the focal length of the twelfth lens is 260mm to 270mm, the image side surface is convex, and the object side surface is flat.

[0012] Furthermore, the air gap between the object-side surface of the ninth lens and the image-side surface of the tenth lens is 0.1 to 0.5 mm; the air gap between the object-side surface of the tenth lens and the image-side surface of the eleventh lens is 0.1 to 0.5 mm; and the air gap between the object-side surface of the eleventh lens and the image-side surface of the twelfth lens is 0.1 to 0.5 mm.

[0013] The present invention also provides an imaging device, which includes a lens and an image sensor for capturing images through the lens; wherein the lens includes any of the above-mentioned microscope objective lenses.

[0014] Compared with the existing technology, the wide spectrum and ultra-long working distance microscope objective lens provided by the present invention has the following advantages:

[0015] (1) Lens group 1 uses heavy flint glass and lanthanum crown glass to glue together, making the glass structure more stable. Lanthanum crown glass has good optical transmittance, making the glass have better light transmittance, while heavy flint glass performs well in thermal stability, which can make the glass combination safer when used in a high-temperature environment and improve the overall optical effect. Through reasonable optical focal length distribution (1.7≤|f1 / f|≤2.2; 3.4≤|f2 / f|≤3.9; 2.5≤|f3 / f|≤3), under this condition, using the first lens group designed by the present invention, the microscope objective lens of the present invention can increase the objective lens working distance, and the working distance can reach 150mm, greatly improving the operability and versatility when using the microscope objective lens, making the optical path construction more compatible, and can be widely used in the production and processing of precision machinery, thereby successfully designing the microscope objective lens of the present invention into a wide spectrum ultra-long working distance microscope objective lens with NA=0.15.

[0016] (2) The microscope objective lens of the present invention adopts a specific combination of multiple doublets and triplet lens groups (the first lens group is a doublet lens group; the second lens group is a triplet lens group; the third lens group includes two doublet lens groups in sequence from the image side to the object side), and performs chromatic aberration correction to ensure accurate color reproduction without introducing special glass CaF2 or binary diffraction elements. Lens group 2 uses a triplet of heavy lanthanum flint, heavy flint glass, and heavy lanthanum flint glass. The heavy lanthanum flint glass helps to reduce the dispersion in the long wavelength band and control the chromatic aberration in the red and yellow areas; the heavy flint glass compensates for the higher dispersion characteristics in the short wavelength band (such as blue and purple), ensuring that the entire spectrum remains consistent in the image. Through reasonable combination, the overall spectral performance of the system is optimized, so that the optical performance in the entire spectral range tends to be balanced, avoiding serious chromatic aberration or image distortion in specific bands. The large amount of fluorine crown glass and lanthanum crown glass used in lens group 3 is because the third lens group bears most of the optical power of the microscope objective lens. These selected glasses all have a higher refractive index than ordinary crown glass and lower dispersion than flint glass. Proper selection and combination effectively improves the imaging quality of the optical system, resulting in excellent image quality from the microscope objective.

[0017] (3) On the basis of reasonable optical focal length distribution, combined with a specific combination of multiple groups of doublets and triplet lenses, the microscope objective lens of the present invention can ensure an ultra-long working distance while having a flat field of view, easy processing and inspection, and excellent imaging quality, thereby solving the defect that the existing technology cannot achieve a microscope objective lens with high imaging quality at an ultra-long working distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure is a schematic diagram of the optical structure of a wide-spectrum ultra-long working distance microscope objective lens provided by an embodiment of the present invention.

[0019] Figure 2 yes Figure 1 Modulation transfer function graph of a microscope objective.

[0020] Figure 3 yes Figure 1 Spot diagram of a microscope objective.

[0021] Figure 4 yes Figure 1 Axial chromatic aberration curve of a microscope objective.

[0022] Figure 5 yes Figure 1 Distortion diagram of a microscope objective. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] See also Figure 1 , which is a schematic diagram of the structure of a wide-spectrum, ultra-long working distance microscope objective lens described in an embodiment of the present invention. The microscope objective lens can be used in an imaging device, which may include a lens and an image sensor that captures images through the lens. The lens can employ the microscope objective lens. The microscope objective lens comprises, from the image side IMA to the object side OBJ, a first lens group G1, a second lens group G2, an aperture STO, and a third lens group G3, all having the same optical axis.

[0026] The microscope objective lens satisfies the following conditions: (1) 1.7 ≤ |f1 / f| ≤ 2.2; (2) 3.4 ≤ |f2 / f| ≤ 3.9; and (3) 2.5 ≤ |f3 / f| ≤ 3. Where f is the total focal length of the microscope objective lens, and f1, f2, and f3 are the focal lengths of the first lens group G1, the second lens group G2, and the third lens group G3, respectively. The focal powers of the first lens group G1, the second lens group G2, and the third lens group G3 cooperate with each other to ensure smooth light propagation throughout the system.

[0027] The first lens group G1 of this embodiment is used to increase the working distance of the objective lens. The first lens group G1 has negative optical power and includes, in sequence from the image side IMA to the object side OBJ along the same optical axis, a first lens L1 and a second lens L2. The object-side surface of the first lens L1 and the image-side surface of the second lens L2 are cemented together. The first lens L1 is a meniscus lens with negative optical power, having a focal length of -40 mm to -30 mm, and can be made of environmentally friendly heavy flint glass. The image-side surface S1 of the first lens L1 is concave, and the object-side surface S2 of the first lens L1 is convex. The second lens L2 is a biconcave lens with negative optical power, having a focal length of -20 mm to -10 mm, and is made of environmentally friendly lanthanum crown glass. The image-side surface of the second lens L2 (because the object-side surface of the first lens L1 and the image-side surface of the second lens L2 are cemented together, the image-side surface of the second lens L2, i.e., the object-side surface S2) is concave, and the object-side surface S3 of the second lens L2 is concave.

[0028] The microscope objective lens of this embodiment has a reasonable optical power distribution (1.7≤|f1 / f|≤2.2; 3.4≤|f2 / f|≤3.9; 2.5≤|f3 / f|≤3). Under this condition, the first lens group G1 can increase the working distance of the microscope objective lens of the present invention to 150 mm, greatly improving the operability and versatility of the microscope objective lens, making the optical path construction more compatible, and can be widely used in the production and processing of precision machinery. As a result, the microscope objective lens of the present invention is successfully designed as a wide-spectrum, ultra-long-working-distance microscope objective lens with a numerical aperture NA = 0.15.

[0029] The second lens group G2 is used for field flattening and secondary spectrum correction. It has negative optical power and, along the same optical axis, includes, in order from the image side (IMA) to the object side (OBJ), the third lens L3, the fourth lens L4, and the fifth lens L5. The air spacing between the object-side surface (S3) of the second lens L2 and the image-side surface (S4) of the third lens L3 is 51.3 to 51.8 mm; the object-side surface (S5) of the third lens L3 is cemented to the image-side surface of the fourth lens L4; and the object-side surface (S6) of the fourth lens L4 is cemented to the image-side surface of the fifth lens L5.

[0030] The third lens L3 is a biconcave lens with negative focal power, with a focal length of -30mm to -20mm. It is made of environmentally friendly heavy lanthanum flint glass. The image-side surface S4 of the third lens L3 is concave, and the object-side surface S5 of the third lens L3 is concave. The fourth lens L4 is a biconvex lens with positive focal power, with a focal length of 20mm to 30mm. It is made of environmentally friendly heavy lanthanum flint glass. The image-side surface S5 of the fourth lens L4 is convex, and the object-side surface S6 of the fourth lens L4 is convex. The fifth lens L5 is a biconcave lens with negative focal power, with a focal length of -80mm to -70mm. It is made of environmentally friendly heavy lanthanum flint glass. The image-side surface S6 of the fifth lens L5 is concave, and the object-side surface S7 of the fifth lens L5 is concave.

[0031] The third lens group G3 is used to take on most of the optical power and has positive optical power. It includes, from the image side IMA to the object side OBJ along the same optical axis, 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.

[0032] The air gap between the object-side surface S7 of the fifth lens L5 and the image-side surface S8 of the sixth lens L6 is 26.9-27.4 mm; the object-side surface S9 of the sixth lens L6 is cemented with the image-side surface of the seventh lens L7; the air gap between the object-side surface S10 of the seventh lens L7 and the image-side surface S11 of the eighth lens L8 is 0.1-0.5 mm; the object-side surface S12 of the eighth lens L8 is cemented with the image-side surface of the ninth lens L9; the air gap between the object-side surface S13 of the ninth lens L9 and the image-side surface S14 of the tenth lens L10 is 0.1-0.5 mm; the air gap between the object-side surface S15 of the tenth lens L10 and the image-side surface S16 of the eleventh lens L11 is 0.1-0.5 mm; and the air gap between the object-side surface S17 of the eleventh lens L11 and the image-side surface S18 of the twelfth lens L12 is 0.1-0.5 mm.

[0033] The sixth lens element L6 is a biconcave lens with negative focal power, with a focal length of -60mm to -50mm. It is made of environmentally friendly heavy lanthanum flint glass. The image-side surface S8 of the sixth lens element L6 is concave, and the object-side surface S9 of the sixth lens element L6 is concave. The seventh lens element L7 is a biconvex lens with positive focal power, with a focal length of 30mm to 40mm. It is made of environmentally friendly fluorine crown glass. The image-side surface S10 of the seventh lens element L7 is convex, and the object-side surface S10 of the seventh lens element L7 is convex. The eighth lens element L8 is a biconcave lens with negative focal power, with a focal length of -30mm to -20mm. It is made of environmentally friendly lanthanum crown glass. The image-side surface S11 of the eighth lens element L8 is concave, and the object-side surface S12 of the eighth lens element L8 is concave. The ninth lens element, L9, is a positive biconvex lens with a focal length of 70mm to 80mm. It is made of environmentally friendly fluor-crown glass. Its image-side surface is convex, and its object-side surface, S13, is convex. The tenth lens element, L10, is a positive biconvex lens with a focal length of 120mm to 130mm. It is made of environmentally friendly fluor-crown glass. Its image-side surface, S14, is convex, and its object-side surface, S15, is convex. The eleventh lens element, L11, is a positive biconvex lens with a focal length of 80mm to 90mm. It is made of environmentally friendly heavy phosphorus crown glass. Its image-side surface, S16, is convex, and its object-side surface, S17, is convex. The twelfth lens L12 is a convex-plano lens with positive refractive power and a focal length of 260 mm to 270 mm. The material of the lens is environmentally friendly lanthanum crown glass. The image-side surface S18 of the twelfth lens L12 is convex, and the object-side surface S19 of the twelfth lens L12 is flat.

[0034] 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 all spherical lenses, which are easy to process and inspect.

[0035] The microscope objective lens of the present invention adopts a specific combination of multiple doublets and triplets (the first lens group G1 is a doublet; the second lens group G2 is a triplet; the third lens group G3 includes two doublets in sequence from the image side IMA to the object side OBJ), and performs chromatic aberration correction to ensure accurate color reproduction without introducing special glass CaF2 or binary diffraction elements.

[0036] The present invention is an infinite conjugate imaging system that adopts a reverse design. The incident polychromatic light beam emitted by the object plane OBJ passes through the third lens group G3, the aperture STO, the second lens group G2 and the first lens group G1 in sequence, and then emerges as a parallel light beam, which is then converged by the tube lens to form an image. The microscope objective lens is combined with the tube lens to form a parallel light beam in the middle optical path. Different filters and components such as spectroscopes can be added as needed to expand the use. On the basis of reasonable optical focal length distribution, combined with a specific combination of multiple groups of doublets and triplet lens groups, the microscope objective lens of the present invention can ensure an ultra-long working distance while having a flat field of view, easy processing and inspection, and excellent imaging quality. The present invention solves the defect that the existing technology cannot achieve a high-quality microscope objective lens with an ultra-long working distance.

[0037] In this embodiment, the microscope objective lens is simulated using the optical parameters shown in Table 1.

[0038] Table 1 Specific optical parameters of microscope objective

[0039]

[0040] In the embodiment, the focal length f1 of the first lens group G1 is -38 mm, the focal length f2 of the second lens group G2 is -72 mm, and the focal length f3 of the third lens group G3 is 60 mm. The working distance WD is 150 mm, the field of view FN is 1.5 mm, the operating wavelength is 500 nm to 600 nm, the numerical aperture NA is 0.15, the effective focal length f is 20 mm, and the magnification is 5x.

[0041] like Figure 2 As shown, the transfer function image in the embodiment of the present invention represents the resolution capability at different line pairs in the meridian plane and sagittal plane for each wavelength in each field of view of the optical system. The horizontal axis represents the number of resolvable line pairs, and the vertical axis represents the contrast. The higher the contrast, the better the imaging quality. It can be seen from the figure that the transfer function of the present invention is close to the diffraction limit and has excellent imaging quality.

[0042] Please combine Figure 3 、 Figure 4 、 Figure 5 , Figure 3 This is the spot diagram of this embodiment, which directly reflects the optical performance. Figure 3 It can be seen that the diffuse spots of the full field of view of the present invention are mostly within the Airy disk, and have excellent imaging quality. Figure 4 This is the full-field axial aberration curve of this embodiment, the horizontal axis is the normalized entrance pupil diameter, and the vertical axis represents the lateral aberration, the unit is micrometer. Figure 4 It can be seen that the maximum focal shift between 550 nm and 600 nm of the present invention is less than 4 μm, which meets the achromatic condition. Figure 5 This is the distortion curve of this embodiment, where the horizontal axis is the distortion ratio in %, and the vertical axis is the field of view in degrees. Figure 5 It can be seen that the maximum distortion of the present invention is 0.44%, and the distortion is effectively corrected.

[0043] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0044] The above-described embodiment merely represents one embodiment of the present invention. While the description is relatively specific and detailed, it should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, and such modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A wide spectrum ultra-long working distance microscope objective lens, comprising, from the image side to the object side, a first lens group, a second lens group, a stop, and a third lens group having the same optical axis; characterized in that: The microscope objective lens satisfies: 1.7≤|f1 / f|≤2.2; 3.4≤|f2 / f|≤3.9; 2.5≤|f3 / f|≤3; Wherein, f is the total focal length of the microscope objective lens, f1, f2, and f3 are the focal lengths of the first lens group, the second lens group, and the third lens group, respectively; The first lens group has negative optical power and includes, from the image side to the object side along the optical axis, a first lens made of heavy flint glass and a second lens made of lanthanum crown glass. The first lens is a meniscus lens with negative optical power, having a focal length of -40 mm to -30 mm, with a concave image-side surface and a convex object-side surface. The second lens is a biconcave lens with negative optical power, having a focal length of -20 mm to -10 mm, with a concave image-side surface and a concave object-side surface. The object-side surface of the first lens and the image-side surface of the second lens are cemented together. The second lens group has negative optical power and includes, from the image side to the object side along the optical axis, a third lens which is a biconcave lens with negative optical power, a fourth lens which is a biconvex lens with positive optical power, and a fifth lens which is a biconcave lens with negative optical power; the object-side surface of the third lens is cemented to the image-side surface of the fourth lens; and the object-side surface of the fourth lens is cemented to the image-side surface of the fifth lens. The third lens group has positive optical power and includes, from the image side to the object side along the optical axis, a sixth lens which is a biconcave lens with negative optical power, a seventh lens which is a biconvex lens with positive optical power, an eighth lens which is a biconcave lens with negative optical power, a ninth lens which is a biconvex lens with positive optical power, a tenth lens which is a biconvex lens with positive optical power, an eleventh lens which is a biconvex lens with positive optical power, and a twelfth lens which is a convex-plano lens with positive optical power.

2. The wide spectrum ultra-long working distance microscope objective lens according to claim 1, characterized in that: The first lens group is a doublet lens group; the second lens group is a triplet lens group; and the third lens group includes two doublet lens groups in sequence from the image side to the object side.

3. The wide spectrum ultra-long working distance microscope objective lens according to claim 1, characterized in that: The air gap between the first lens group and the second lens group is within 51.3-51.8 mm; the air gap between the second lens group and the third lens group is within 26.9-27.4 mm.

4. The wide spectrum ultra-long working distance microscope objective lens according to claim 1, characterized in that: The third lens and the fifth lens are both made of heavy lanthanum flint glass, and the fourth lens is made of heavy flint glass.

5. The wide spectrum ultra-long working distance microscope objective lens according to claim 4, characterized in that: The focal length of the third lens is -30mm~-20mm, the image side surface is concave, and the object side surface is concave; the focal length of the fourth lens is 20mm~30mm, the image side surface is convex, and the object side surface is convex; the focal length of the fifth lens is -80mm~-70mm, the image side surface is concave, and the object side surface is concave.

6. The wide spectrum ultra-long working distance microscope objective lens according to claim 1, characterized in that: The sixth lens is made of heavy lanthanum flint glass, the seventh lens, the ninth lens and the tenth lens are all made of fluorine crown glass, the eighth lens and the twelfth lens are all made of lanthanum crown glass, and the eleventh lens is made of heavy phosphorus crown glass.

7. The wide spectrum ultra-long working distance microscope objective lens according to claim 6, characterized in that: The object-side surface of the sixth lens is cemented to the image-side surface of the seventh lens, the object-side surface of the eighth lens is cemented to the image-side surface of the ninth lens, and the air gap between the object-side surface of the seventh lens and the image-side surface of the eighth lens is within 0.1-0.5 mm.

8. The wide spectrum ultra-long working distance microscope objective lens according to claim 6, characterized in that: The focal length of the sixth lens is -60mm~-50mm, the image side surface is concave, and the object side surface is concave; the focal length of the seventh lens is 30mm~40mm, the image side surface is convex, and the object side surface is convex; the focal length of the eighth lens is -30mm~-20mm, the image side surface is concave, and the object side surface is concave; the focal length of the ninth lens is 70mm~80mm, the image side surface is convex, and the object side surface is convex; the focal length of the tenth lens is 120mm~130mm, the image side surface is convex, and the object side surface is convex; the focal length of the eleventh lens is 80mm~90mm, the image side surface is convex, and the object side surface is convex; the focal length of the twelfth lens is 260mm~270mm, the image side surface is convex, and the object side surface is flat.

9. The wide spectrum ultra-long working distance microscope objective lens according to claim 8, characterized in that: The air gap between the object-side surface of the ninth lens and the image-side surface of the tenth lens is 0.1-0.5 mm; the air gap between the object-side surface of the tenth lens and the image-side surface of the eleventh lens is 0.1-0.5 mm; and the air gap between the object-side surface of the eleventh lens and the image-side surface of the twelfth lens is 0.1-0.5 mm.

10. An imaging device comprising a lens and an image sensor for capturing images through the lens; characterized in that: The lens comprises the microscope objective lens according to any one of claims 1 to 9.

Images