Microobjective and optical detection equipment

Abstract

The invention provides a microscope objective and optical detection equipment, and belongs to the technical field of optical imaging. The microscope objective comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens which are sequentially arranged from the image side to the object side. The first lens is a first biconvex lens, the second lens is a first positive meniscus lens, the third lens is a first negative meniscus lens, the fourth lens is a first biconcave lens, the fifth lens is a first triplet lens, and the sixth lens is a second biconvex lens. The seventh lens is a second triplet lens, and the eighth lens is a doublet lens and is used for correcting spherical aberration, coma aberration, astigmatism and chromatic aberration of the microscope objective; the ninth lens is a third biconvex lens. Compared with a conventional 8X microscope objective product, the microscope objective provided by the invention has the advantages that the resolution is remarkably improved, the field of view is increased by nearly four times, the test precision and apochromatic design are improved, and a switching light source can be ensured not to be out of focus.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular to a microscope objective lens and optical detection equipment. Background Art

[0002] Biological microscopes are one of the indispensable tools in life science research, and optical performance is a key factor affecting the imaging quality of microscopes. Important parameters for measuring the optical performance of objective lenses include numerical aperture (NA), working distance (WD) and chromatic aberration (CA). Numerical aperture refers to the tangent value of the half angle of the maximum allowable incident light on the front focal plane of the objective lens. The larger the numerical aperture, the higher the resolution of the imaging and the clearer the image. The working distance refers to the distance from the front surface of the objective lens to the sample plane. The longer the working distance, the thicker the sample can be accommodated, and a variety of different imaging modes can also be performed, such as reflection, fluorescence and confocal. Chromatic aberration refers to the different focal lengths of light of different wavelengths after passing through the lens, resulting in color deviation in the image.

[0003] With the rapid development of life science research, cryogenic microscopy has become an important branch of life science research. Conventional microscope objectives have a small numerical aperture and low resolution, which cannot meet the needs of high-resolution scenes. Summary of the invention

[0004] In view of this, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a microscope objective and an optical detection device.

[0005] In a first aspect, the present invention provides a microscope objective lens, characterized in that it comprises: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence from the image side to the object side; Among them, the first lens is a first biconvex lens, which is used to increase the angle of light collection of the microscope objective lens; the second lens is a first positive meniscus lens, which is used to expand the focal length of the microscope objective lens; the third lens is a first negative meniscus lens, which is used to reduce the spherical aberration of the microscope objective lens; the fourth lens is a first biconcave lens, which is used to correct the field curvature of the microscope objective lens; the fifth lens is a first triplet lens, which is used to perform a primary correction on the spherical aberration, coma, astigmatism and chromatic aberration of the microscope objective lens; the sixth lens is a second biconvex lens; the seventh lens is a second triplet lens, which is used to perform a secondary correction on the spherical aberration, coma, astigmatism and chromatic aberration of the microscope objective lens; the eighth lens is a doublet lens, which is used to correct the spherical aberration, coma, astigmatism and chromatic aberration of the microscope objective lens; and the ninth lens is a third biconvex lens.

[0006] In some embodiments, the fifth lens includes a fourth biconvex lens, a second biconcave lens, and a fifth biconvex lens sequentially arranged along the light transmission direction.

[0007] In some embodiments, the seventh lens includes a first meniscus lens, a second meniscus lens, and a sixth biconvex lens sequentially arranged along the light transmission direction.

[0008] In some embodiments, the aperture of the first lens is larger than the aperture of the sixth lens, and the aperture of the sixth lens is larger than the aperture of the ninth lens.

[0009] In some embodiments, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is f7, the focal length of the eighth lens is f8, and the focal length of the ninth lens is f9; Among them, 175mm≤f1≤185mm, 70mm≤f2≤75mm, -40mm≤f3≤-35mm, -20mm≤f4≤-10mm, 110mm≤f5≤115mm, 50mm≤f6≤55mm, 85mm≤f7≤90mm, -115mm≤f8≤-110mm, and 35mm≤f9≤40mm.

[0010] In some embodiments, the focal length f1 of the first lens is 180 mm, the focal length f2 of the second lens is 72.8 mm, the focal length f3 of the third lens is -39.65 mm, the focal length f4 of the fourth lens is -15.52 mm, the focal length f5 of the fifth lens is 111.66 mm, the focal length f6 of the sixth lens is 51.03 mm, the focal length f7 of the seventh lens is 87.63 mm, the focal length f8 of the eighth lens is -113.33 mm, and the focal length f9 of the ninth lens is 37.83 mm.

[0011] In some embodiments, the aperture of the microscope objective lens is 0.45, and the resolution of the microscope objective lens is 0.75 μm.

[0012] In some embodiments, the working distance of the microscope objective lens is 19 mm, and the maximum size of an object that can be photographed by the microscope objective lens is 5 mm.

[0013] In some embodiments, the second lens has a first image end surface and a first object end surface, the first image end surface is convex, and the first object end surface is concave; The first image end surface faces the first lens, and the first object end surface faces the third lens.

[0014] In a second aspect, the present invention provides an optical detection device, comprising the microscope objective lens.

[0015] The embodiments of the present invention have the following advantages: compared with conventional 8X microscope objective products, the numerical aperture of the microscope objective provided by the present invention is increased by nearly 1 times, and the resolution is significantly improved, the field of view is increased by nearly 4 times, and the equipment efficiency is improved. In addition, the microscope objective provided by the present application is an object-side telecentric system, which not only improves the test accuracy and achromatic design, but also can ensure that the switching light source does not defocus.

[0016] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic structural diagram of a viewing angle of a microscope objective lens provided by some embodiments of the present invention is shown; Figure 2 shows the MTF curve of the object-side alignment plane of the microscope objective provided by some embodiments of the present invention; Figure 3 shows the field curvature curves of the microscope objective lenses provided by some embodiments of the present invention; Figure 4 shows the distortion curves of the microscope objective lenses provided by some embodiments of the present invention; Figure 5 shows chromatic aberration curves of microscope objective lenses provided by some embodiments of the present invention; Figure 6 The graph shows the defocus performance curve of the microscope objective lens provided by some embodiments of the present invention.

[0019] Description of main component symbols: 100 - first lens; 200 - second lens; 300 - third lens; 400 - fourth lens; 500 - fifth lens; 600 - sixth lens; 700 - seventh lens; 800 - eighth lens; 900 - ninth lens. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0021] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[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 this application belongs. The terms used herein in the specification of the template are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0025] like Figure 1 As shown, some embodiments of the present invention provide a microscope objective lens, which is mainly used for the needs of high-resolution scenes and reduces parallax.

[0026] The microscope objective lens includes a first lens 100, a second lens 200, a third lens 300, a fourth lens 400, a fifth lens 500, a sixth lens 600, a seventh lens 700, an eighth lens 800 and a ninth lens 900 which are arranged in sequence from the image side to the object side.

[0027] The first lens 100 is a first biconvex lens, so as to increase the angle of light collected by the microscope objective lens through the first biconvex lens. It is understandable that by increasing the aperture of the first lens 100, the first lens 100 can collect more light, thereby effectively improving the resolution.

[0028] The second lens 200 is a first positive meniscus lens, which is used to expand the focal length of the microscope objective lens. It can be understood that the first positive meniscus lens has a positive focal length, which is used to minimize or correct the spherical aberration introduced by the first lens 100 through the first positive meniscus lens, and to increase the working distance of the microscope objective lens and the numerical aperture of the system.

[0029] The third lens 300 is a first negative meniscus lens, which is used to reduce the spherical aberration of the microscope objective lens. It should be noted that in this embodiment, the third lens 300 has a negative focal length, so as to further reduce the spherical aberration through the third lens 300 and improve the imaging quality and resolution of the microscope objective lens.

[0030] The fourth lens 400 is a first biconcave lens, and the fourth lens 400 is used to adjust the entry mode and refraction direction of light, thereby correcting the field curvature of the microscope objective lens to ensure the quality and clarity of imaging.

[0031] The fifth lens 500 is a first triplet lens, which is used to correct the spherical aberration, coma, astigmatism and chromatic aberration of the microscope objective lens, so as to improve the accuracy of observation and measurement of the microscope objective lens and improve the imaging quality.

[0032] It should be noted that coma is an imaging error of the optical system. When a monochromatic conical light beam emitted by an off-axis object point outside the main axis to the optical system is refracted, if it cannot form a clear point on the ideal plane, but forms a comet-shaped light spot with a bright tail, this phenomenon is called coma.

[0033] The sixth lens 600 is a second biconvex lens, wherein the aperture of the sixth lens 600 is smaller than the aperture of the first lens 100 , so that the sixth lens 600 converges the light passing through the fifth lens 500 to adjust the angle of the light entering the seventh lens 700 .

[0034] The seventh lens 700 is a second triplet lens, which is used to perform secondary correction on the spherical aberration, coma, astigmatism and chromatic aberration of the microscope objective lens, so as to further improve the accuracy of observation and measurement of the microscope objective lens, and improve the imaging quality and resolution.

[0035] The eighth lens 800 is a doublet lens, which is used to correct the spherical aberration, coma, distortion, astigmatism and chromatic aberration of the microscope objective lens, so as to improve the imaging quality and enhance the performance and resolution of the microscope objective lens.

[0036] The ninth lens 900 is a third biconvex lens, and the aperture of the ninth lens 900 is smaller than the aperture of the sixth lens 600, so as to increase the working distance of the microscope objective lens, so as to converge the light passing through the eighth lens 800 to the surface of the object through the ninth lens 900, so as to improve the resolution and quality of the microscope objective lens imaging. The microscope objective lens provided by the present invention can make the numerical aperture of the microscope objective lens not greater than 0.45, the resolution reaches 0.75μm, the working distance is 19mm, and the maximum size of the photographable object is 5mm, which can meet the needs of high-resolution scenes.

[0037] Specifically, compared with conventional 8X microscope objective products, the microscope objective provided by the present invention has a numerical aperture increased by nearly 1 times, and the resolution is significantly improved, the field of view is increased by nearly 4 times, and the equipment efficiency is improved. In addition, the microscope objective provided by the present application is an object-side telecentric system, which not only improves the test accuracy and achromatic design, but also can ensure that the switching light source does not defocus.

[0038] like Figure 1 As shown, in this embodiment, the aperture of the first lens 100 is larger than the aperture of the sixth lens 600 , and the aperture of the sixth lens 600 is larger than the aperture of the ninth lens 900 .

[0039] It is understandable that by increasing the aperture of the first lens 100 to increase the angle at which the microscope collects light, more light can be gathered, thereby improving the clarity and resolution of the microscope imaging. By adjusting the aperture of the sixth lens 600, it is ensured that the sixth lens 600 can adjust the angle of the light passing through the fifth lens 500, so that the light passing through the sixth lens 600 can reach a preset angle. By adjusting the aperture of the ninth lens 900, it is ensured that the light passing through the eighth lens 800 can be completely gathered to the surface of the object to be measured, thereby improving the resolution and imaging quality of the microscope imaging.

[0040] like Figure 1 As shown, in this embodiment, the fifth lens 500 includes a fourth biconvex lens, a second biconcave lens and a fifth biconvex lens arranged in sequence along the light transmission direction. The fifth lens 500 is formed by sequentially gluing the fourth biconvex lens, the second biconcave lens and the fifth biconvex lens together to improve the spherical aberration, coma, astigmatism and chromatic aberration of the microscope objective lens, so as to improve the imaging quality and resolution.

[0041] like Figure 1As shown, in this embodiment, the seventh lens 700 includes a first meniscus lens, a second meniscus lens and a sixth biconvex lens arranged in sequence along the light transmission direction. The fifth lens 500 is formed by sequentially gluing the first meniscus lens, the second meniscus lens and the sixth biconvex lens together to further improve the spherical aberration, coma, astigmatism and chromatic aberration of the microscope objective lens, so as to further improve the imaging quality and resolution.

[0042] like Figure 1 As shown, in this embodiment, the second lens 200 has a first image end surface and a first object end surface, the first image end surface is convex, the first object end surface is concave, the first image end surface faces the first lens 100, and the first object end surface faces the third lens 300.

[0043] Specifically, the curvature of the first image end surface is greater than the curvature of the first object end surface. It is understandable that the second lens 200 has a positive focal length, so that the spherical aberration is reduced by the second lens 200, thereby improving the imaging quality and resolution of the microscope objective.

[0044] It should be noted that an object-space telecentric system is an optical system in which the system's aperture diaphragm is imaged at infinity by the lens in front of it, resulting in the chief ray being parallel to the optical axis. The characteristic of this system is that when the object moves forward and backward in the optical system, the image point position does not change but becomes blurred. The object-space telecentric system is designed so that the entrance pupil is located at an infinite distance in the object space. This means that no matter where the object is located, the chief ray always remains parallel to the optical axis, thereby eliminating the magnification changes caused by changes in the object's position. ‌Object-space telecentric lenses can provide more accurate measurements because the movement of the object does not affect the imaging magnification. Object-space telecentricity is achieved by placing the system's aperture diaphragm at the focal point of the front group. This design ensures that the field of view does not change no matter where the object plane is located because the chief ray defining the field of view is exactly parallel to the optical axis. ‌

[0045] In some embodiments, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is f7, the focal length of the eighth lens is f8, and the focal length of the ninth lens is f9; Among them, 175mm≤f1≤185mm, 70mm≤f2≤75mm, -40mm≤f3≤-35mm, -20mm≤f4≤-10mm, 110mm≤f5≤115mm, 50mm≤f6≤55mm, 85mm≤f7≤90mm, -115mm≤f8≤-110mm, and 35mm≤f9≤40mm.

[0046] In some embodiments, the focal length f1 of the first lens is 180 mm, the focal length f2 of the second lens is 72.8 mm, the focal length f3 of the third lens is -39.65 mm, the focal length f4 of the fourth lens is -15.52 mm, the focal length f5 of the fifth lens is 111.66 mm, the focal length f6 of the sixth lens is 51.03 mm, the focal length f7 of the seventh lens is 87.63 mm, the focal length f8 of the eighth lens is -113.33 mm, and the focal length f9 of the ninth lens is 37.83 mm.

[0047] It can be understood that by adjusting the focal length of each lens to a preset value, the real image formed by the object can be clearer. By adjusting the focal length, the light can be better focused on the imaging plane, thereby improving the quality of imaging and the resolution of the microscope objective.

[0048] Table 1 In this embodiment, the specific lens data of each lens is shown in Table 1. The numerical aperture NA of the microscope objective is 0.45, the resolution is 0.75μm, the maximum size of the sensor supporting the tube lens is φ40mm, the maximum size of the photographable object is 5mm, and the working distance is 19mm.

[0049] Specifically, it can be seen from Table 1 that the curvature radius of the first lens away from the second lens is 178.1244mm, and the curvature radius of the first lens toward the second lens is -235.2618mm; the curvature radius of the second lens away from the third lens is 17.92245mm, and the curvature radius of the second lens toward the third lens is 21.09706mm; the curvature radius of the third lens away from the fourth lens is 20.20472mm, and the curvature radius of the third lens toward the fourth lens is 11.85005mm; the curvature radius of the fourth lens away from the fifth lens is -24.51475 The curvature radius of the fourth lens facing the fifth lens is 24.51475mm; the curvature radius of the fourth biconvex lens away from the sixth lens is 135.672mm, and the curvature radius of the fourth biconvex lens facing the sixth lens is 135.672mm; the curvature radius of the second biconcave lens away from the seventh lens is -70.50576mm, and the curvature radius of the second biconcave lens facing the seventh lens is -70.50576mm; the curvature radius of the fifth biconvex lens away from the seventh lens is 27.17807mm, and the curvature radius of the fifth biconvex lens facing the seventh lens is -46.15 917mm; the curvature radius of the sixth lens away from the seventh lens is 71.45399mm, and the curvature radius of the sixth lens facing the seventh lens is -48.92983mm; the curvature radius of the first meniscus lens away from the eighth lens is 55.24421mm, and the curvature radius of the first meniscus lens facing the eighth lens is 55.24421mm; the curvature radius of the second meniscus lens away from the eighth lens is 164.9008mm, and the curvature radius of the second meniscus lens facing the eighth lens is 164.9008mm; the curvature radius of the sixth biconvex lens away from the eighth lens is 31.0 234mm, the curvature radius of the sixth biconvex lens toward the eighth lens is -36.10152mm; the curvature radius of the eighth lens away from the ninth lens is 42.67011mm, and the curvature radius of the eighth lens toward the ninth lens is 42.67011mm; the curvature radius of the ninth lens toward the tenth lens is -35.59159mm, and the curvature radius of the ninth lens away from the tenth lens is 92.71067mm; the curvature radius of the tenth lens toward the ninth lens is 32.9986mm, and the curvature radius of the tenth lens away from the ninth lens is -231.1449mm.

[0050] It can be understood that by adjusting the radius of curvature of each lens to a preset value to ensure that the light is correctly focused, the imaging quality and resolution are improved, so that the numerical aperture of the microscope objective is not greater than 0.45, the resolution reaches 0.75μm, the working distance is 19mm, and the maximum size of the photographable object is 5mm, thereby meeting the needs of high-resolution scenes.

[0051] Figure 2 The figure shows the MTF curve of the object side near field plane of the microscope objective. It can be seen from the figure that the resolution: 900 lp / mm>20%, reaching the diffraction limit.

[0052] Figure 3 This is a field curvature diagram of the microscope objective of the present invention. From the distribution of the field curvature, it can be seen that the field curvature of the microscope objective optical system is controlled within ±1 μm, that is, the field curvature is less than 1 μm, so that the central resolution of the microscope objective optical system is optimal.

[0053] Figure 4 This is a distortion diagram of the microscope objective optical system of the present invention. From the distribution of the distortion, it can be seen that the distortion of each object side half field point is less than 0.2%, so that the center resolution of the microscope objective optical system is optimal.

[0054] Figure 5 This is a chromatic aberration diagram of the microscope objective optical system of the present invention. It can be seen from the diagram that the chromatic aberration of the microscope objective optical system is controlled within 0.5um, so that the center resolution of the microscope objective optical system is optimal.

[0055] Figure 6 This is a defocus performance diagram of the microscope objective optical system of the present invention. It can be seen from the diagram that the defocus performance of the microscope objective optical system is controlled within 3um, so that the center resolution of the microscope objective optical system is optimal.

[0056] Based on the same inventive concept, the present invention further provides an automatic optical detection device, which includes the microscope objective lens as described in any of the above embodiments, which will not be described in detail herein.

[0057] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limiting, and thus other examples of the exemplary embodiments may have different values.

[0058] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0059] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. 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.

Claims

1. A microscope objective lens, It is characterized in that include: A first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens are sequentially arranged from the image side to the object side; Among them, the first lens is a first biconvex lens, which is used to increase the angle of light collection of the microscope objective lens; the second lens is a first positive meniscus lens, which is used to expand the focal length of the microscope objective lens; the third lens is a first negative meniscus lens, which is used to reduce the spherical aberration of the microscope objective lens; the fourth lens is a first biconcave lens, which is used to correct the field curvature of the microscope objective lens; the fifth lens is a first triplet lens, which is used to perform a primary correction on the spherical aberration, coma, astigmatism and chromatic aberration of the microscope objective lens; the sixth lens is a second biconvex lens; the seventh lens is a second triplet lens, which is used to perform a secondary correction on the spherical aberration, coma, astigmatism and chromatic aberration of the microscope objective lens; the eighth lens is a doublet lens, which is used to correct the spherical aberration, coma, astigmatism and chromatic aberration of the microscope objective lens; and the ninth lens is a third biconvex lens.

2. The microscope objective lens according to claim 1, It is characterized in that The fifth lens includes a fourth biconvex lens, a second biconcave lens and a fifth biconvex lens sequentially arranged along the light transmission direction.

3. The microscope objective lens according to claim 1, It is characterized in that The seventh lens includes a first meniscus lens, a second meniscus lens and a sixth biconvex lens arranged in sequence along the light transmission direction.

4. The microscope objective lens according to claim 1, It is characterized in that The aperture of the first lens is larger than that of the sixth lens, and the aperture of the sixth lens is larger than that of the ninth lens.

5. The microscope objective lens according to claim 1, It is characterized in that The focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is f7, the focal length of the eighth lens is f8, and the focal length of the ninth lens is f9; Among them, 175mm≤f1≤185mm, 70mm≤f2≤75mm, -40mm≤f3≤-35mm, -20mm≤f4≤-10mm, 110mm≤f5≤115mm, 50mm≤f6≤55mm, 85mm≤f7≤90mm, -115mm≤f8≤-110mm, and 35mm≤f9≤40mm.

6. The microscope objective lens according to claim 5, It is characterized in that The focal length f1 of the first lens is 180 mm, the focal length f2 of the second lens is 72.8 mm, the focal length f3 of the third lens is -39.65 mm, the focal length f4 of the fourth lens is -15.52 mm, the focal length f5 of the fifth lens is 111.66 mm, the focal length f6 of the sixth lens is 51.03 mm, the focal length f7 of the seventh lens is 87.63 mm, the focal length f8 of the eighth lens is -113.33 mm, and the focal length f9 of the ninth lens is 37.83 mm.

7. The microscope objective according to any one of claims 1 to 6, It is characterized in that The aperture of the microscope objective lens is 0.45, and the resolution of the microscope objective lens is 0.75 μm.

8. The microscope objective lens according to claim 7, It is characterized in that The working distance of the microscope objective lens is 19 mm, and the maximum size of the object that can be photographed by the microscope objective lens is 5 mm.

9. The microscope objective according to any one of claims 1 to 6, It is characterized in that The second lens has a first image end surface and a first object end surface, the first image end surface is a convex surface, and the first object end surface is a concave surface; The first image end surface faces the first lens, and the first object end surface faces the third lens.

10. An optical detection device, It is characterized in that The microscope objective lens comprises the microscope objective lens as claimed in any one of claims 1 to 9.

Images