Wide-spectrum super-long working distance microscope objective and image capturing device thereof

Abstract

The invention relates to a wide-spectrum super-long working distance microscope objective and an image capturing device thereof in the technical field of optical imaging. The microscope objective sequentially comprises a first lens group, a second lens group, a diaphragm and a third lens group from an image side to an object side, wherein the first lens group, the second lens group, the diaphragm and the third lens group have the same optical axis and meet 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, and f1, f2 and f3 are the focal lengths of the three lens groups respectively. The first lens group has negative focal power and sequentially comprises a first lens which is a meniscus lens with negative focal power and a second lens which is a biconcave lens with negative focal power from the image side to the object side along the optical axis. The focal length of the first lens ranges from-40 mm to-30 mm. The focal length of the second lens is-20mm to-10mm, and the object side surface of the first lens is glued with the image side surface of the second lens. The ultra-long working distance is guaranteed, meanwhile, the view field is flat, machining and detection are easy, the imaging quality is good, and the defect that in the prior art, a high-imaging-quality microscope objective cannot achieve the ultra-long working distance at the same time is overcome.

Description

Technical Field

[0001] The invention relates to a microscope objective lens in the technical field of optical imaging, 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 the diversified application scenarios of microscopic inspection expand, higher requirements are placed on the operability of microscope objective lenses, that is, the demand for ultra-long working distances. Ultra-long working distance microscope objective lenses can provide more space between the microscope objective lens and the observed sample, making it compatible with the rest of the inspection system components and easy to focus, reducing the risk of damaging the observed sample. Therefore, further increasing the working distance of the microscope objective lens and ensuring the imaging quality, thereby improving the operability of its application, is of great significance for microscopic inspection.

[0003] The ultra-long working distance objective lens model 378-802-6 in the M Plan Apo series of Japan's Mitutoyo has a wavelength range of 436-656nm, a magnification of 5 times, and a working distance of only 34mm. Another example is the long working distance objective lens model MY5X-822 of the American Sorebo Company, which has a wavelength range of 480-1800nm, a magnification of 5 times, and a working distance of 37.5mm. Existing products and technologies cannot meet the needs of sample observation 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. The purpose is to solve the defect that the microscope objective lens with high imaging quality in the prior art cannot realize an ultra-long working distance.

[0005] The present invention is implemented by the following technical scheme: a wide spectrum ultra-long working distance microscope objective lens, which includes a first lens group, a second lens group, an aperture and a third lens group with the same optical axis from the image side to the object side. The microscope objective lens satisfies: 1.7≤|f1 / f|≤2.2; 3.4≤|f2 / f|≤3.9; 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, the second lens group and the third lens group respectively. Among them, the first lens group has negative optical focal 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 focal power, and 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 double concave lens with negative optical focal power, and its focal length is -20mm to -10mm, and 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 glued 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 of the above solution, 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; the object side surface of the fourth lens is cemented to the image side surface of the fifth lens.

[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 of the above scheme, 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-planar lens with positive optical power. Further, the object side surface of the sixth lens is glued to the image side surface of the seventh lens, the object side surface of the eighth lens is glued 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 to 0.5 mm.

[0011] Further, 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 a plane.

[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; 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 comprises a lens and an image sensor for capturing images through the lens; wherein the lens comprises any of the above-mentioned microscope objective lenses.

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

[0015] (1) Lens group 1 uses heavy flint glass and lanthanum crown glass to glue, making the glass structure more stable. Lanthanum crown glass has good optical transmittance, making the glass have better light transmittance, while heavy flint glass has good 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, the first lens group designed by the present invention is adopted, and the microscope objective lens of the present invention can increase the working distance of the objective lens, and the working distance can reach 150mm, which greatly improves the operability and versatility when using the microscope objective lens, making the compatibility of the optical path construction stronger, and can be widely used in the production and processing of precision machinery, so that the microscope objective lens of the present invention is successfully designed as 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 groups of double-cemented lens groups and triple-cemented lens groups (the first lens group is a double-cemented lens group; the second lens group is a triple-cemented lens group, and the third lens group includes two groups of double-cemented lens groups from the image side to the object side in sequence), and performs chromatic aberration correction to ensure accurate color reproduction without introducing special glass CaF2 or binary diffraction elements. Lens group 2 uses heavy lanthanum flint, heavy flint glass, and heavy lanthanum flint glass triple-cemented. The heavy lanthanum flint glass helps to reduce the dispersion in the long-wave 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-wave 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 reason why fluorine crown glass and lanthanum crown glass are used in large quantities in lens group 3 is that the third lens group bears most of the optical power of the microscope objective lens. These selected glasses have higher refractive index than ordinary crown glass and lower dispersion than flint glass. Reasonable selection and matching can effectively improve the imaging quality of the optical system, making the image quality of the microscope objective lens excellent.

[0017] (3) On the basis of reasonable optical focal length distribution, combined with a specific combination of multiple groups of double-cemented lens groups and triple-cemented 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, thereby solving the defect that the prior art 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 present invention is a schematic diagram of the optical structure of a wide-spectrum ultra-long working distance microscope objective 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 be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work 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 those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related 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 introduced in an embodiment of the present invention. The microscope objective lens can be applied to an imaging device, and the imaging device may include a lens and an image sensor that captures images through the lens, wherein the lens can use the microscope objective lens. The microscope objective lens includes a first lens group G1, a second lens group G2, an aperture STO, and a third lens group G3 having the same optical axis from the image side IMA to the object side OBJ.

[0026] The microscope objective lens satisfies: (1) 1.7≤|f1 / f|≤2.2; (2) 3.4≤|f2 / f|≤3.9; (3) 2.5≤|f3 / f|≤3. In the formula, 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 optical focal lengths of the first lens group G1, the second lens group G2, and the third lens group G3 cooperate with each other to ensure smooth propagation of the overall light of 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 a first lens L1 and a second lens L2 in sequence from the image side IMA to the object side OBJ along the same optical axis. The object side surface of the first lens L1 and the image side surface of the second lens L2 are cemented. The first lens L1 is a meniscus lens with negative optical power, and its focal length is -40mm to -30mm. The material can be 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 double concave lens with negative optical power, and its focal length is -20mm to -10mm. The material is 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, 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 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, and the working distance can reach 150 mm, which greatly improves the operability and versatility when using the microscope objective lens, makes the compatibility of the optical path construction stronger, and can be widely used in the production and processing of precision machinery, so that 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 flattening the field and correcting the secondary spectrum. The second lens group G2 has negative optical power and includes a third lens L3, a fourth lens L4, and a fifth lens L5 in sequence from the image side IMA to the object side OBJ along the same optical axis. The air gap between the object side surface S3 of the second lens L2 and the image side surface S4 of the third lens L3 is 51.3-51.8 mm; the object side surface S5 of the third lens L3 is cemented with the image side surface of the fourth lens L4; the object side surface S6 of the fourth lens L4 is cemented with the image side surface of the fifth lens L5.

[0030] The third lens L3 is a double concave lens with negative focal power, with a focal length of -30mm to -20mm, and 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 double convex lens with positive focal power, with a focal length of 20mm to 30mm, and 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 double concave lens with negative focal power, with a focal length of -80mm to -70mm, and 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 bear most of the optical power and has positive optical power. It includes a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, and a twelfth lens L12 in sequence from the image side IMA to the object side OBJ along the same optical axis.

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

[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 test.

[0035] The microscope objective lens of the present invention adopts a specific combination of multiple groups of doublet lens groups and triplet lens groups (the first lens group G1 is a doublet lens group; the second lens group G2 is a triplet lens group, and the third lens group G3 includes two groups of doublet lens groups 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, which adopts a reverse design. The incident complex 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 cooperates with the tube lens to form a parallel light beam in the middle light path, and different filters and spectroscopes can be added according to needs to expand the use. On the basis of reasonable optical focal length distribution, combined with a specific combination of multiple groups of double-cemented lens groups and triple-cemented 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 detection, and excellent imaging quality. The present invention solves the defect that the prior art cannot achieve a high-imaging 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 number FN is 1.5 mm, the working band 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 5 times.

[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 of each wavelength in each field of view in 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 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 : 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 550nm and 600nm of the present invention is less than 4μm, which meets the achromatic condition. Figure 5 is a distortion curve diagram of this embodiment, wherein 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-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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 only expresses one implementation of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention application. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention application shall be based on the attached 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; Among them, the first lens group has negative optical power, and includes a first lens made of heavy flint glass and a second lens made of lanthanum crown glass 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, whose focal length is -40mm to -30mm, and the image side surface is concave, and the object side surface is convex; the second lens is a double concave lens with negative optical power, whose focal length is -20mm to -10mm, the image side surface is concave, and the object side surface is concave; the object side surface of the first lens and the image side surface of the second lens are glued together.

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 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.

4. The wide spectrum ultra-long working distance microscope objective lens according to claim 1, characterized in that: 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 glued to the image side surface of the fourth lens; the object side surface of the fourth lens is glued to the image side surface of the fifth lens; 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 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.

6. The wide spectrum ultra-long working distance microscope objective lens according to claim 1, characterized in that: 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; 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 glued to the image side surface of the seventh lens, the object side surface of the eighth lens is glued 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 to 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 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 a plane.

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 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; 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.

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 as claimed in any one of claims 1 to 9.

Images